WO2016125313A1

WO2016125313A1 - Purge-liquid circulation device for blood pump, and auxiliary artificial heart system

Info

Publication number: WO2016125313A1
Application number: PCT/JP2015/053443
Authority: WO
Inventors: 妃咲木下; 智哉北野
Original assignee: 株式会社サンメディカル技術研究所
Priority date: 2015-02-06
Filing date: 2015-02-06
Publication date: 2016-08-11
Also published as: JPWO2016125313A1; JP6343821B2

Abstract

The present invention provides a purge-liquid circulation device for a blood pump, wherein sealing performance of a sliding device is improved in comparison to conventional blood pumps. The purge-liquid circulation device (200) for a blood pump is provided with: a sliding device (1) which is used while a first sliding surface of a fixed-side sliding member and a second sliding surface of a rotation-side sliding member are in a state of facing each other, and the respective outer peripheral sides of the fixed-side sliding member and the rotation-side sliding member are in a state of being in contact with blood; a purge-liquid circulation unit (210) which causes a purge liquid to circulate to the fixed-side sliding member and the rotation-side sliding member; and a purge-liquid circulation path (420) which is configured so as to allow the purge liquid to circulate. The purge-liquid circulation unit (210) is provided with: a purge-liquid circulation pump (212) for applying a motive force to the purge liquid; and a flow-rate adjustment valve (214) capable of adjusting the flow rate of the purge liquid when the purge liquid, having passed along the respective inner peripheral sides of the fixed-side sliding member and the rotation-side sliding member, is returned to a purge-liquid storage unit.

Description

Purge solution circulating device for blood pump and auxiliary artificial heart system

The present invention relates to a purge fluid circulation device for a blood pump for circulating a purge fluid having a function of maintaining lubrication performance, cooling performance and sealing performance inside the blood pump, and an auxiliary artificial device using the purge fluid circulation device for the blood pump. Relates to the kidney system.

2. Description of the Related Art Conventionally, blood pumps having functions such as lubrication, cooling, and maintenance of sealing performance inside blood pumps by circulating a liquid made of water, physiological saline, or the like inside a blood pump used in an auxiliary artificial heart system are known. (For example, refer to Patent Document 1). The “auxiliary artificial heart system” is a medical device used for patients with severe heart failure, and refers to a system that supplements a part of the function of the heart in order to maintain the life of the patient. Moreover, the liquid which consists of the water which circulates through the inside of a blood pump, physiological saline, etc. may be called a cool seal liquid or a purge liquid. In this specification, it will be expressed as “purge liquid”.

FIG. 8 is a cross-sectional view of a conventional blood pump 900. FIG. 8A is a cross-sectional view of blood pump 900, and FIG. 8B is an enlarged view of the range indicated by symbol A in FIG. 8A.

A conventional blood pump 900 includes a sliding device 901 as shown in FIG. The sliding device 901 includes a stationary sliding member 912 having an annular first sliding surface 914 and a rotating sliding member 922 having an annular second sliding surface 924, and the first sliding surface 914 is provided. And the second sliding surface 924 are opposed to each other, and the outer peripheral sides of the stationary-side sliding member 912 and the rotating-side sliding member 922 are in contact with blood. This sliding device 901 is also a component of a mechanical seal.

The conventional blood pump 900 includes a fixed unit 910, a rotating unit 920, a rotation driving device 930, and a purge fluid circulation path 940 in the blood pump 900 in addition to the sliding device 901. The purge fluid circulation path 940 in the blood pump 900 is referred to as “blood pump purge fluid circulation path 940”.
The fixed-side sliding member 912 is also a member that constitutes the fixed portion 910.
The rotation side sliding member 922 is also a member that constitutes the rotation unit 920.
The rotating unit 920 includes an impeller 926 and a rotating shaft 928 in addition to the rotating side sliding member 922.

The blood pump purge fluid circulation path 940 is a path for circulating the purge liquid in the blood pump 900. The blood pump purge fluid circulation path 940 includes a purge fluid inlet 942, a purge fluid supply chamber 944, a purge fluid passage chamber 946, and a purge fluid outlet 948.
The purge liquid passage chamber 946 is located on each inner peripheral side of the fixed side sliding member 912 and the rotation side sliding member 922 in the sliding device 901.

The blood pump 900 configured in this way is a blood pump that is used while allowing purge liquid to pass through the inner peripheral sides of the stationary sliding member 912 and the rotating sliding member 922 in the sliding device 901. Although not explicitly described in Patent Document 1, the auxiliary artificial heart system is provided with a purge liquid circulating device for circulating the purge liquid, and the purge liquid is circulated by the purge liquid circulating device. ing.

The purge fluid circulation device (referred to as a conventional purge fluid circulation device) has a purge fluid circulation unit used outside the user's body, and a tube (feed-side tube) between the purge fluid circulation unit and the blood pump 900. And the purge solution through the return side tube). Specifically, although not shown in the drawings, the purge liquid stored in the purge liquid storage section (also referred to as a reservoir) provided in the purge liquid circulation unit is pumped out by the purge liquid circulation pump and slides. The purge liquid is circulated in such a manner that after passing through the respective inner peripheral sides of the fixed-side sliding member 912 and the rotation-side sliding member 922 in the apparatus 901, it is returned to the reservoir and sent out again by the purge liquid circulation pump. Further, since the blood may be mixed into the purge liquid when the purge liquid passes through the blood pump, the purge liquid circulation unit is also provided with a filter for removing blood mixed in the purge liquid. .

JP 2013-85913 A

By the way, in the technical field of blood pumps, there is a demand for higher operational stability. Here, the operational stability is to stabilize power consumption necessary for the operation of the blood pump 900 and to stabilize the rotation of the rotating unit 920.
In order to further increase the operational stability, firstly, the lubrication performance of the sliding device 901 is increased, and secondly, the sealing performance of the sliding device 901 is increased. The sealing performance is also referred to as sealing performance or leakage performance, and is performance that suppresses blood on the outer peripheral side of the sliding device 901 from entering (leaking) the inner peripheral side of the sliding device 901. Say.

Here, as a factor of lowering the operational stability, it is difficult to supply the purge liquid between the first sliding surface 914 and the second sliding surface 924, or the first sliding surface and the second sliding due to wear. The coefficient of friction increases due to the change in the shape of the surface, or a specific component (mainly plasma protein) in the blood accumulates between the first sliding surface 914 and the second sliding surface 924. Is mentioned. In order to suppress the occurrence of these factors and further increase the operational stability, it is important to increase the lubrication performance of the sliding device 901 and the sealing performance of the sliding device 901.

In order to increase the lubrication performance of the sliding device 901 and to increase the sealing performance of the sliding device 901, the sliding device 901 has a fixed sliding member 912 and a rotating sliding member 922 on each inner peripheral side. It is important to set the pressure of the existing purge liquid to an appropriate pressure and supply the purge liquid between the first sliding surface 914 and the second sliding surface 924 in a stable state. This is because when the pressure of the purge liquid in the sliding device 901 is low, blood enters between the first sliding surface 914 and the second sliding surface 924, and further, the fixed-side sliding member 912 in the sliding device 901. This is because there may be a case where the rotation side sliding member 922 enters the inner peripheral side.
Note that increasing the lubrication performance of the sliding device 901 and increasing the sealing performance of the sliding device 901 are abbreviated as “increasing the lubrication performance and sealing performance of the sliding device 901”.

By the way, as described above, the purge liquid stored in the reservoir is circulated by being sent out by the purge liquid circulation pump, passing through the blood pump, and then returning to the reservoir. Since the sliding device 901 is generally at a substantially intermediate position between the feed side tube and the return side tube, each inner periphery of the fixed side sliding member 912 and the rotation side sliding member 922 in the sliding device 901 is provided. The pressure of the purge liquid existing on the side is approximately an average value of the pressure of the purge liquid in the vicinity of the outlet in the purge liquid circulation unit and the pressure of the purge liquid in the reservoir (this is atmospheric pressure, which is 0 KPa).
Note that “the pressure of the purge liquid existing on each inner peripheral side of the fixed side sliding member 912 and the rotation side sliding member 922 in the sliding device 901” is referred to as “the pressure of the purge liquid in the sliding device 901”. Abbreviated.

Here, the pressure of the purge liquid in the vicinity of the outlet in the purge liquid circulation unit can be set in a range of 10 KPa to 100 KPa, depending on the performance of the purge liquid circulation pump. In this case, the pressure of the purge liquid in the moving device 901 is 15 KPa. Note that the pressure of the purge liquid in the vicinity of the outlet in the purge liquid circulation unit (in this case, 30 KPa) is relative to the pressure of the purge liquid in the reservoir as atmospheric pressure and the pressure in the reservoir as a reference (0 KPa). Pressure.

As described above, the pressure of the purge liquid in the sliding device 901 is almost ½ of the pressure of the purge liquid near the outlet of the purge liquid circulation unit. However, if the human blood pressure (the average blood pressure in the systole and the diastole) is 100 mmHg (13 KPa), the pressure of the purge liquid in the sliding device 901 is about 15 KPa in many cases. Since the pressure of the purge fluid is superior to the blood pressure, the purge fluid overcomes the blood resistance and is supplied between the first sliding surface 914 and the second sliding surface 924.

However, in some cases, the blood pressure may exceed the pressure of the purge solution. In such a case, the purge solution is difficult to be supplied between the first sliding surface 914 and the second sliding surface 924. Therefore, there is a problem that the lubrication performance and sealing performance of the sliding device are lowered.

The present invention has been made in view of the above circumstances, and by setting the pressure of the purge liquid in the sliding device to an appropriate pressure, the lubricating performance and sealing performance of the sliding device can be improved as compared with the conventional purge liquid circulating device. An object of the present invention is to provide a purge fluid circulating device for a blood pump that can be made high. It is another object of the present invention to provide an auxiliary artificial heart system including the blood pump purge fluid circulation device of the present invention.

[1] A purge solution circulating apparatus for a blood pump according to the present invention is provided inside a blood pump embedded in a user's body, and has a fixed-side sliding member having an annular first sliding surface and an annular second slide. A rotation-side sliding member having a moving surface, wherein the first sliding surface and the second sliding surface are opposed to each other, and the fixed-side sliding member and the rotation-side sliding member A sliding device that is used in a state where each outer peripheral side of the blood pump is in contact with blood, and a purge solution having a function of maintaining the lubrication performance, cooling performance, and sealing performance inside the blood pump, and the fixed-side sliding member and A purge liquid circulation unit that circulates through each inner peripheral side of the rotation side sliding member, and the purge liquid circulation from the purge liquid circulation unit through each inner peripheral side of the fixed side sliding member and the rotation side sliding member. Purge fluid circulation configured to return to the unit A purge fluid circulation device for a blood pump comprising a path, wherein the purge fluid circulation unit is unidirectional to a purge fluid reservoir that stores the purge fluid and a purge fluid that is stored in the purge fluid reservoir. A purge liquid circulation pump that provides a moving force of the purge liquid, and a purge liquid reservoir that is provided in the vicinity of the purge liquid inlet of the purge liquid reservoir and passes through the inner peripheral sides of the fixed-side sliding member and the rotating-side sliding member. And a flow rate adjusting valve capable of adjusting the flow rate of the purge liquid when returning to the section.

According to the purge solution circulating apparatus for a blood pump of the present invention, in addition to the purge solution circulation pump, there is a flow rate adjustment valve capable of adjusting the flow rate of the purge solution when returning to the purge solution storage part. Thus, by controlling at least one of the purge liquid circulation pump and the flow rate adjustment valve, the pressure of the purge liquid existing on each inner peripheral side of the fixed side sliding member and the rotation side sliding member is set to an appropriate pressure (for example, The pressure is surely higher than the pressure of blood existing on the outer peripheral surface of the sliding device.

It should be noted that “the pressure of the purge liquid existing on each inner peripheral side of the fixed side sliding member and the rotation side sliding member” is also abbreviated as “the pressure of the purge liquid in the sliding device” here. Further, in this specification, controlling the purge liquid circulation pump means controlling the amount of purge liquid delivered per unit time by controlling the number of revolutions of the purge liquid circulation pump. Further, controlling the flow rate adjusting valve means controlling the opening of the flow rate adjusting valve (the flow rate of the purge liquid flowing through the flow rate adjusting valve).

As described above, according to the purge fluid circulation device of the blood pump of the present invention, by controlling at least one of the purge fluid circulation pump and the flow rate adjusting valve, the pressure of the purge fluid in the sliding device is set to an appropriate pressure (for example, The pressure is surely higher than the blood pressure existing on the outer peripheral surface of the sliding device. Therefore, the purge liquid can be forcibly supplied between the first sliding surface of the fixed-side sliding member and the second sliding surface of the rotating-side sliding member. A lubricating film can be stably formed between the sliding surface and the second sliding surface of the rotating side sliding member. Thereby, blood can be prevented from entering the inner peripheral side of the sliding device, and the lubrication performance and sealing performance of the sliding device can be made higher than those of the conventional purge liquid circulating device.

[2] In the purge solution circulating apparatus for the blood pump of the present invention, the first sliding surface and the second sliding surface in contact with each other are formed by the fixed sliding member and the rotating sliding member. When the pressure of the purge liquid at the non-contact state due to the pressure of the purge liquid existing on each inner peripheral side is the divergence pressure of the purge liquid, each of the fixed side sliding member and the rotation side sliding member Purge liquid circulation having a function of controlling at least one of the purge liquid circulation pump and the flow rate adjusting valve so that the pressure of the purge liquid existing on the circumferential side is slightly lower than the pressure of the purge liquid divergence It is preferable to further include a unit controller.

Thereby, the pressure of the purge liquid in the sliding device can be set to a value slightly lower than the detachment pressure of the purge liquid. In this way, by setting the pressure of the purge liquid in the sliding device to a value slightly lower than the detachment pressure of the purge liquid, the pressure of the purge liquid in the sliding device is compared with the case where the purge liquid is simply circulated. And higher values. Accordingly, the purge liquid can be forcibly supplied between the first sliding surface of the fixed-side sliding member and the second sliding surface of the rotating-side sliding member. A lubricating film can be stably formed between the sliding surface and the second sliding surface of the rotating side sliding member. Thereby, blood can be prevented from entering the inner peripheral side of the sliding device.

[3] In the purge solution circulating apparatus for a blood pump according to the present invention, the purge solution circulation unit controller keeps the flow rate adjusting valve closed and the purge solution circulation pump continues to send the purge solution at a constant flow rate. The pressure of the purge liquid when the increase of the pressure of the purge liquid existing on each inner peripheral side of the fixed side sliding member and the rotation side sliding member stops and the pressure of the purge liquid starts to rapidly decrease It is preferable to further have a function of measuring as the dissociation pressure.

This makes it possible to measure the dissociation pressure of the purge solution. That is, when the purge fluid circulation pump continues to feed the purge fluid at a constant flow rate with the flow rate adjusting valve closed, the pressure of the purge fluid in the sliding device increases. When the first sliding surface of the stationary sliding member and the second sliding surface of the rotating sliding member are brought into a non-contact state (dissociated state) from the contact state due to the pressure of the purge liquid, The increase in the pressure of the purge liquid stops and the pressure of the purge liquid starts to decrease rapidly. The pressure at this time (the pressure when the pressure of the purge liquid in the sliding device stops increasing and the pressure of the purge liquid starts to drop rapidly) can be measured as the “displacement pressure of the purge liquid”.

[4] In the purge solution circulating apparatus for the blood pump of the present invention, the pressure slightly lower than the divergence pressure of the purge solution is preferably in the range of 85% to 95% of the divergence pressure.

By setting the pressure slightly lower than the purge liquid separation pressure in such a range, the pressure of the purge liquid in the sliding device is set to an appropriate pressure (for example, the pressure of blood existing on the outer peripheral surface of the sliding device). Higher pressure). Note that the pressure slightly lower than the divergence pressure of the purge liquid is more preferably about 90% in the range of 85% to 95%.

[5] In the purge solution circulating apparatus for a blood pump according to the present invention, the purge solution circulation unit is provided on the downstream side of the purge solution circulation pump, and is included in the purge solution circulating through the purge solution circulation path. A filter for removing unnecessary substances, a first pressure detection unit for detecting the pressure of the purge liquid in the vicinity of the purge liquid inlet of the filter, and a second pressure detection unit for detecting the pressure of the purge liquid in the vicinity of the purge liquid outlet of the filter And a third pressure detector for detecting the pressure of the purge liquid in the vicinity of the purge liquid inlet of the flow rate adjusting valve.

By providing a filter as a component of the purge fluid circulation unit, unnecessary substances such as blood and bacteria contained in the circulating purge fluid can be removed. Further, the clogging of the filter can be detected by providing the first pressure detection unit as a component of the purge liquid circulation unit.

The second pressure detector as a component of the purge liquid circulation unit detects the pressure of the purge liquid in the vicinity of the purge liquid outlet of the filter. The second pressure detector is in the vicinity of the purge liquid outlet of the filter. The pressure of the purge liquid can be detected as the outlet side pressure of the purge liquid circulation unit. For this reason, the filter outlet side pressure detected by the second pressure detector can be referred to as “the outlet side pressure of the purge liquid circulation unit”. Further, by providing the second pressure detection unit, the purge fluid circulation path (connecting tube connecting the purge fluid circulation unit and the blood pump) existing between the purge fluid circulation unit and the blood pump is bent or twisted. It is also possible to detect stenosis due to.

Also, by providing the third pressure detector as a component of the purge fluid circulation unit, the pressure of the purge fluid flowing into the flow rate adjustment valve can be detected. In the state where the purge liquid is circulating, the pressure of the purge liquid in the sliding device is determined based on the pressure detected by the third pressure detector and the pressure detected by the second pressure detector. You can know what the pressure is. In addition, since the third pressure detection unit detects the pressure of the purge liquid in the vicinity of the purge liquid inlet of the flow rate adjustment valve, the valve inlet side pressure detected by the third pressure detection unit is “purge liquid circulation unit”. It can be said that "the inlet side pressure".

[6] In the purge solution circulating apparatus for a blood pump of the present invention, it is preferable that at least one of the fixed-side sliding member and the rotating-side sliding member is made of silicon carbide.

Silicon carbide (SiC) is a material excellent in hardness, durability and biocompatibility, and can be used safely in blood. For this reason, by adopting the configuration as described above, it is possible to increase the hardness and durability of the fixed-side sliding member and the rotating-side sliding member, and to suppress the influence caused by elastic deformation of the sliding surface. It becomes possible.

It is preferable that both the fixed-side sliding member and the rotating-side sliding member are sliding members made of silicon carbide, but one of the fixed-side sliding member and the rotating-side sliding member is made of silicon carbide, and the other is A sliding member made of carbon is also preferable. Carbon is a relatively soft material suitable for use with silicon carbide, has excellent biocompatibility, and can be used safely in blood.

In addition, the sliding member made of silicon carbide may have been subjected to a “familiarization treatment” which is a treatment for forming a hydrate of silicon oxide on the sliding surface before being assembled as a sliding device. preferable. With such a configuration, the sliding surface of the sliding member made of silicon carbide has “highly hydrophilic silicon oxide hydrate” by a tribochemical reaction. For this reason, it becomes difficult for blood to adhere to the sliding surface, and as a result, sliding resistance when used in blood can be reduced as compared with a sliding device that is not subjected to the “familiar treatment”.

“Family processing” refers to a process of applying friction to the sliding surface while increasing the load according to a predetermined procedure. For example, the conforming process increases the load by a predetermined value (for example, 50 N) after applying friction to the sliding surface until the rate of change of the friction coefficient is within a predetermined value (for example, 5%) at a constant load. Can be performed. The familiar process is performed in water, for example. The maximum load applied during the conforming process is preferably larger than the load applied when the sliding device is actually used, and more preferably 10 times or more of the load.

[7] In the purge solution circulating apparatus of the blood pump of the present invention, it is preferable that anti-thrombotic treatment is performed on each outer periphery of the stationary side sliding member and the rotating side sliding member.

By adopting such a configuration, it is possible to suppress thrombus generation and blood adhesion on the outer circumferences of the stationary-side sliding member and the rotating-side sliding member.
Examples of the antithrombotic treatment include coating treatment with MPC (2-methacryloyloxyethyl phosphorylcholine) polymer.

[8] The auxiliary artificial heart system of the present invention includes a blood pump implanted in the body, an artificial blood vessel for connecting the blood pump and the blood flow of the heart, and a blood pump control for driving and controlling the blood pump. An auxiliary artificial heart system comprising a device and a blood pump purge fluid circulation device for circulating a purge fluid inside the blood pump, wherein the blood pump purge fluid circulation device comprises the above [1] to [7]. ] The purge solution circulating device for a blood pump according to any one of the above.

According to the auxiliary artificial heart system of the present invention, since the purge fluid circulating device for the blood pump of the present invention described in any one of [1] to [7] is provided, any of [1] to [7] described above. This has the same effect as the purge solution circulating apparatus for the blood pump of the present invention. Thereby, the auxiliary artificial heart system of the present invention becomes a reliable auxiliary artificial heart system.

It is a figure shown in order to demonstrate the auxiliary artificial heart system 100 which concerns on embodiment. It is sectional drawing of the blood pump 110 used for the auxiliary artificial heart system 100 shown in FIG. It is a figure shown in order to demonstrate the sliding apparatus 1 used for the blood pump shown in FIG. It is a figure shown in order to demonstrate the purge liquid circulation apparatus 200 of the blood pump which concerns on embodiment. The pressure change when the purge fluid circulation pump 212 is operated so that the purge fluid is sent at a low flow rate (the flow rate is constant) in a state where the flow rate adjustment valve 214 is closed (a state where the opening degree is zero) is schematically illustrated. FIG. It is a figure which shows typically the mode of the pressure of the purge liquid in the sliding apparatus. FIG. 4 is a diagram schematically showing a relationship between purge liquid and blood between a first sliding surface and a second sliding surface. It is sectional drawing of the conventional blood pump 900. FIG.

Hereinafter, the purge solution circulating device and the auxiliary artificial heart system of the blood pump of the present invention will be described based on the embodiments shown in the drawings. Each figure is a schematic diagram, and the size and the like of each component do not necessarily accurately reflect the actual one.

FIG. 1 is a diagram for explaining an auxiliary artificial heart system 100 according to an embodiment.
FIG. 2 is a cross-sectional view of blood pump 110 used in assistive artificial heart system 100 shown in FIG.
FIG. 3 is a view for explaining the sliding device 1 used in the blood pump shown in FIG. 3A is a perspective view of the sliding device 1 and its vicinity, and FIG. 3B is a cross-sectional view of the sliding device 1 and its vicinity.
FIG. 4 is a view for explaining the purge solution circulating apparatus 200 of the blood pump according to the embodiment.

As shown in FIG. 1, an auxiliary artificial heart system 100 according to the embodiment includes a blood pump 110 (see FIG. 2 for details) implanted in the body, and an artificial for connecting the blood pump 110 and the blood flow of the heart. The

blood vessels

120 and 130, a portable auxiliary artificial heart system main body 300, and a connection cable 400 for connecting the blood pump 110 and the portable auxiliary artificial heart system main body 300 are provided.

In the auxiliary artificial heart system 100 according to the embodiment configured as described above, the sliding device 1 (see FIG. 3 for details) provided in the blood pump 110 and the auxiliary artificial heart system main body 300. Connected to a purge fluid circulation unit 210 (see FIG. 4 for details) housed in the body, and a purge fluid circulation unit controller 220 (see FIG. 4) housed in the auxiliary artificial heart system main body 300. The purge fluid circulation tube 410 (see FIG. 4), which is one of the components of the cable 400, is used for the purge fluid circulation device of the blood pump of the present invention (here, the purge fluid circulation device 200 of the blood pump according to the embodiment). Is configured).

The auxiliary artificial heart system main body 300 also stores a blood pump control device for driving and controlling the blood pump 110, although not shown. A control signal line (not shown) for the blood pump control device to drive and control the blood pump 110 is included in the connection cable 400.

As shown in FIG. 2, the blood pump 110 includes a fixed portion 10, a rotating portion 20, a rotation driving device 30, and a blood pump chamber 32. The blood pump 110 configured as described above is disposed in purge liquid passage chambers 46 (described later) located on the inner peripheral sides of the stationary sliding member 12 and the rotating sliding member 22 in the sliding device 1. This pump is used while passing the purge liquid.

The fixed portion 10 includes a cylindrical fixed-side sliding member 12 (so-called seat ring).
The rotating unit 20 includes a rotating side sliding member 22 (so-called seal ring), an impeller 26 and a rotating shaft 28. The impeller 26 applies a moving force to the blood. The rotation shaft 28 is connected to the rotation drive device 30, and when used, the rotation drive device 30 applies a rotational force to rotate the entire rotation unit 20.

The fixed sliding member 12 and the rotating sliding member 22 constitute the sliding device 1. The sliding device 1 is one of the components constituting a mechanical seal in the blood pump. The sliding device 1 is also one of the components of the purge solution circulating device 200 of the blood pump according to the embodiment. The sliding device 1 will be described in detail later. In addition, although illustration, a display of a code | symbol, and detailed description are abbreviate | omitted, a mechanical seal is predetermined in the direction in alignment with the rotating shaft a (refer FIG. 3) of the rotation side sliding member 22 besides the sliding apparatus 1. FIG. It includes components necessary for the mechanical seal, such as a load applying mechanism (for example, using a magnet) that applies the above load, and a cushion ring disposed between the rotation-side sliding member 22 and the impeller 26.

The rotation drive device 30 includes a rotation motor and applies a rotational force to the impeller 26. The blood pump chamber 32 is a place where blood is given a moving force by the impeller 26.

The blood pump 110 is provided with a path 40 (referred to as a blood pump purge liquid circulation path 40) through which the purge liquid circulates. The purge fluid circulation path 40 in the blood pump allows purge fluid to pass through the blood pump 110 in the order of the purge fluid inlet chamber 42, the purge fluid supply chamber 44, and the purge fluid passage chamber 46, and is discharged from the purge fluid outlet 48.

The purge liquid has a function of maintaining lubrication, cooling, and sealing performance in the blood pump 110. Specifically, the function of performing lubrication and cooling between the rotating shaft 28 and the fixed portion 10, the first sliding surface 14 of the fixed-side sliding member 12 and the second sliding surface 24 of the rotating-side sliding member 22. A function of suppressing blood from entering through a gap between the first sliding surface 14 and the second sliding surface 24.

Next, the sliding device 1 will be described.
As shown in FIG. 3, the sliding device 1 includes a stationary sliding member 12 having an annular first sliding surface 14 and a rotating sliding member 22 having an annular second sliding surface 24. . The sliding device 1 is in a state where the first sliding surface 14 and the second sliding surface 24 are opposed to each other, and the outer peripheral sides of the stationary-side sliding member 12 and the rotating-side sliding member 22 are in contact with blood. It is a sliding device used in the state made to do. The sliding device 1 is one of the components of the blood pump 110, but is also a component of the purge solution circulating device 200 of the blood pump according to the embodiment.

The sliding device 1 is in contact with the first sliding surface 14 and the second sliding surface 24 when not in use. In the purge liquid circulation device 200 according to the embodiment, the first sliding surface 14 and the second sliding surface 24 in the sliding device 1 have the same inner diameter and outer diameter in design. Yes. For this reason, the 1st sliding surface 14 and the 2nd sliding surface 24 contact in the whole surface (refer FIG.3 (b) and FIG.3 (c)).

Here, when not in use, the first sliding surface 14 and the second sliding surface 24 are configured so as to rotate with the fixed-side sliding member 12 using a load applying mechanism of a mechanical seal. This can be realized by applying a load to the side sliding member 22. The magnitude of the load depends on the areas of the first sliding surface 14 and the second sliding surface 24, but can be, for example, 10 KPa to 200 KPa.

The sliding device 1 is a sliding device to be used in a state where a predetermined load is applied between the fixed sliding member 12 and the rotating sliding member 22 in the direction along the rotation axis a of the rotating sliding member 22. A moving device (a sliding device having a so-called thrust bearing structure).

In use, the sliding device 1 allows the purge liquid to pass through the inner peripheral sides of the stationary-side sliding member 12 and the rotating-side sliding member 22, that is, the purge liquid passage chamber 46 (see FIG. 2). use.

The fixed side sliding member 12 is made of silicon carbide, and the rotation side sliding member 22 is made of carbon.
Anti-thrombotic treatment is performed on the outer peripheries of the stationary-side sliding member 12 and the rotating-side sliding member 22. An example of the antithrombotic treatment is a coating treatment with MPC (2-methacryloyloxyethyl phosphorylcholine) polymer.

Next, the purge solution circulating apparatus 200 for the blood pump according to the embodiment will be described. The blood pump purge fluid circulation device 200 (hereinafter, “blood pump” may be abbreviated as “purge fluid circulation device 200”) is provided in the blood pump 110 as shown in FIG. And a purge fluid circulation unit 210 that circulates the purge fluid in the blood pump 110, and a purge fluid circulation unit controller 220 that controls the purge fluid circulation unit 210.

The purge fluid circulation unit controller 220 mainly controls the purge fluid circulation pump 212 and the flow rate adjustment valve 214 provided in the purge fluid circulation unit 210, and is packaged on a circuit board (not shown), for example. It is mounted as an electronic circuit.

In the purge fluid circulation device 200 configured as described above, most of the components of the purge fluid circulation device 200 are accommodated in a portable artificial heart system main body 300 (see FIG. 1). The purge fluid circulation unit 210 of the purge fluid circulation device 200 is connected to the purge fluid circulation path 40 in the blood pump in the blood pump 110 via a flexible connection cable 400 (see FIG. 1). Yes. As described above, the connection cable 400 includes the purge solution circulation tube 410 for circulating the purge solution and the control signal line (not shown) from the blood pump control device (not shown). ing.

The purge fluid circulation tube 410 includes a feed-side tube 411 for sending the purge fluid delivered from the purge fluid circulation unit 210 to the blood pump 110, and the purge fluid circulated through the purge fluid circulation path 40 in the blood pump. The return side tube 412 is connected to the purge liquid inlet 42 (see FIG. 2), and the return side tube 412 is connected to the purge liquid outlet 48 (see FIG. 2). ing.

The purge fluid circulation unit 210 is detachably stored in the auxiliary artificial heart system main body 300. For this reason, the purge liquid circulation unit 210 can be replaced as necessary.

As shown in FIG. 4, the purge liquid circulation unit 210 includes a purge liquid storage unit (hereinafter referred to as a reservoir) 211 that stores the purge liquid, and a moving force in one direction against the purge liquid stored in the reservoir 211. A purge liquid circulation pump (for example, a diaphragm pump) 212 that circulates the purge liquid by providing the liquid and unnecessary substances such as blood and bacteria included in the circulated purge liquid provided on the downstream side of the purge liquid circulation pump 212 The flow rate adjusting valve 214 capable of setting the pressure of the purge liquid in the sliding device 1 to a predetermined pressure by adjusting the flow rate of the purge liquid returning to the reservoir 211, and the purge liquid inlet of the filter 213 A first pressure detector 215 for detecting the pressure of the purge liquid in the vicinity, and a purge liquid outlet of the filter 213 A second pressure detector 216 that detects the pressure of the purge liquid in the vicinity as the outlet side pressure of the purge liquid circulation unit, and the pressure of the purge liquid in the vicinity of the purge liquid inlet of the flow rate adjustment valve 214 as the inlet side pressure of the purge liquid circulation unit And a third pressure detector 217 for detection.

The purge liquid circulation pump 212 is a pump capable of sending the purge liquid per unit time with an arbitrary delivery quantity within a predetermined range by controlling the rotation speed.
The flow rate adjusting valve 214 can adjust the flow rate of the purge liquid by adjusting the opening degree of the valve. Therefore, for example, “decreasing (or increasing) the flow rate of the purge liquid in the flow rate adjusting valve 214” may be expressed as “decreasing (or increasing) the opening degree of the flow rate adjusting valve 214”. is there.

A purge liquid circulation path (referred to as an in-unit purge liquid circulation path) inside the purge liquid circulation unit 210 includes an in-unit feed-side circulation path 218 that passes from the reservoir 211 through the purge liquid circulation pump 212 and the filter 213, and a flow rate. There is an in-unit return-side circulation path 219 that enters the reservoir 211 through the regulating valve 214. The in-unit feed-side circulation path 218 is connected to the feed-side tube 411 of the purge liquid circulation tube 410, and the in-unit return-side circulation path 219 is connected to the return-side tube 412 of the purge liquid circulation tube 410.

Here, the in-unit feed side circulation path 218 and the in-unit return side circulation path 219 in the purge liquid circulation unit 210, the purge liquid circulation path 40 in the blood pump (see FIG. 2), and the feed of the purge liquid circulation tube 410 are sent. The entire purge liquid circulation path 420 including the side tube 411 and the return side tube 412 is referred to as a “purge liquid circulation path 420”. Therefore, in this specification, when it is simply expressed as “purge liquid circulation path 420”, it indicates the whole.

The first pressure detector 215 detects the pressure of the purge liquid in the vicinity of the purge liquid inlet of the filter 213 (referred to as filter inlet side pressure P1). The second pressure detector 216 detects the pressure of the purge liquid in the vicinity of the purge liquid outlet of the filter 213 (referred to as filter outlet side pressure P2). The third pressure detector 217 detects the pressure of the purge liquid in the vicinity of the purge liquid inlet of the flow rate adjustment valve 214 (referred to as valve inlet side pressure P3).

The second pressure detection unit 216 detects the pressure of the purge liquid in the vicinity of the purge liquid outlet of the filter 213 as the outlet side pressure of the purge liquid circulation unit 210. For this reason, the filter outlet side pressure P2 detected by the second pressure detector 216 can be referred to as “the outlet side pressure of the purge liquid circulation unit 210”.

Further, the third pressure detector 217 detects the pressure of the purge liquid in the vicinity of the purge liquid inlet of the flow rate adjustment valve 214 as the inlet side pressure of the purge liquid circulation unit 210. For this reason, the valve inlet side pressure P3 detected by the third pressure detector 217 can be said to be “the inlet side pressure of the purge liquid circulation unit 210”.

The filter inlet side pressure P1 detected by the first pressure detection unit 215, the filter outlet side pressure detected by the second pressure detection unit 216 (the outlet side pressure of the purge fluid circulation unit 210) P2, and the third pressure detection unit 217 detected The valve inlet side pressure (inlet side pressure of the purge fluid circulation unit 210) P3 is given to the purge fluid circulation unit controller 220, respectively.

The first pressure detection unit 215 detects clogging of the filter 213, and the second pressure detection unit 216 has a function of detecting the outlet side pressure of the purge liquid circulation unit 210. The second pressure detection unit 216 also has a function of detecting stenosis due to bending or twisting of the connection tube 411 existing between the purge fluid circulation unit 210 and the blood pump 110.

The detection of clogging of the filter 213 and the detection of constriction due to bending or twisting of the connection tube 411 are performed by the purge liquid circulation unit control unit 220 using the filter inlet side pressure P1 detected by the first pressure detection unit 215 and the second pressure. This can be performed by monitoring the filter outlet side pressure (the outlet side pressure of the purge liquid circulation unit 210) P2 detected by the pressure detector 216. That is, as a result of detecting the filter inlet side pressure P1 and the filter outlet side pressure, the purge liquid circulation unit control unit 220 generates an alarm when the filter inlet side pressure P1 is equal to or higher than a predetermined value and An alarm is also generated when the side pressure P2 is greater than or equal to a predetermined value.

Note that examples of the alarm include turning on a lamp and generating an alarm sound from an alarm sound generation unit. In addition, the lamp lights up colors corresponding to the filter inlet side pressure P1 and the filter outlet side pressure P2, respectively, and the alarm sound generates sounds corresponding to the filter inlet side pressure P1 and the filter outlet side pressure P2, respectively. Is possible. Such a lamp and an alarm sound generating unit are provided at predetermined positions of the auxiliary artificial system main body 300 (see FIG. 1), although not shown.

By the way, when the purge liquid is circulated normally without clogging in the filter 213 and without being bent or twisted in the purge liquid circulation tube 410, the pressure on the filter outlet side (the outlet side of the purge liquid circulation unit 210) It is assumed that the pressure P2 can be set in the range of 10 KPa to 100 KPa. Note that, as described above, the filter outlet side pressure P2 can be said to be the outlet side pressure of the purge liquid circulation unit 210, and therefore the filter outlet side pressure P2 indicates the outlet side pressure of the purge liquid circulation unit 210.

Note that the pressure P2 on the outlet side of the filter can be set to a value larger than 100 KPa by using a higher-capacity purge liquid circulation pump, but the purge liquid circulation is considered in consideration of practicality such as cost and size. It is necessary to select a pump. As a result of selecting the purge fluid circulation pump in consideration of such points, the purge fluid circulation pump 212 employed in the purge fluid circulation device 200 of the blood pump according to the embodiment has a filter outlet side pressure P2 of 10 KPa to 100 KPa. A range can be set.

Note that the pressure of the purge liquid at the filter outlet side pressure P2 is 10 KPa to 100 KPa relative to the case where the pressure of the purge liquid in the reservoir 211 is the atmospheric pressure and the pressure in the reservoir 211 is the reference (0 KPa). Pressure. The same applies to the pressure of the purge liquid at other positions.

Here, in order to set the filter outlet side pressure P2 to a predetermined pressure (for example, 30 KPa), the purge liquid circulation unit controller 220 is based on the filter outlet side pressure P2 detected by the second pressure detector 216. This is made possible by controlling the purge liquid circulation pump 212. That is, the purge liquid circulation unit controller 220 monitors the filter outlet side pressure P2, and controls the purge liquid circulation pump 212 so that the filter outlet side pressure P2 becomes a predetermined pressure. Thereby, the filter outlet side pressure P2 can be set to a predetermined pressure (for example, 30 KPa).

By the way, the pressure of the purge liquid existing on each inner peripheral side of the stationary sliding member 12 and the rotating sliding member 22 in the sliding device 1 (this pressure is also referred to as “sliding device 1 The pressure of the purge liquid in the above is abbreviated as “the pressure of the purge liquid” in FIG. 2), because the sliding device 1 is at a substantially intermediate position between the feed side tube 411 and the return side tube 412. Almost average value. In other words, the sliding device 1 is provided at a position where the pressure of the purge liquid in the sliding device 1 is approximately an average value of the filter outlet side pressure P2 and the valve inlet side pressure P3. For this reason, the pressure of the purge liquid in the sliding device 1 is approximately an average value of the filter outlet side pressure P2 and the valve inlet side pressure P3.

Therefore, if the opening degree of the flow rate adjusting valve 214 is fully open, the valve inlet side pressure P3 of the flow rate adjusting valve 214 is substantially equal to the pressure of the purge liquid (0 KPa) in the reservoir 211. It becomes approximately 1/2 of the side pressure P2. For example, when the filter outlet side pressure P2 is 30 KPa, the pressure of the purge liquid in the sliding device 1 is approximately 15 KPa.

In order to further improve the lubrication performance and the sealing performance in the sliding device 1, it is preferable to increase the pressure of the purge liquid in the sliding device 1. Therefore, in the purge fluid circulation device 200 of the blood pump according to the embodiment, the pressure of the purge fluid in the sliding device 1 is set to a value slightly lower than the purge fluid detachment pressure (see below).

In this specification, the divergence pressure of the purge liquid means that the first sliding surface 14 of the fixed-side sliding member 12 and the second sliding surface 24 of the rotating-side sliding member 22 are in sliding contact with each other. The pressure of the purge liquid in the sliding device 1 when the non-contact state (disengaged state) is caused by the pressure of the purge liquid in the apparatus 1.

That is, the first sliding surface 14 of the fixed side sliding member 12 and the second sliding surface 24 of the rotating side sliding member 22 are brought into contact with the first sliding surface 14 and the second sliding surface 24. A pressing force is applied to cause the first sliding surface 14 and the second sliding surface 24 to be in contact with each other with a relatively strong force.

The pressing force for bringing the first sliding surface 14 and the second sliding surface 24 into contact works between the fixed-side sliding member 12 and the rotating-side sliding member 22 by a mechanical seal load applying mechanism. A load (pressing force by a magnet) and a pressing force by blood pressure can be mentioned, and a pressing force by a variable element is added to the sum of these pressing forces. Examples of the fluctuation factors include the effects of wear on the first sliding surface 14 and the second sliding surface 24, plasma proteins in blood, and the like.

As described above, even when the first sliding surface 14 and the second sliding surface 24 are in contact with each other with a relatively strong force, the first sliding surface 14 and the second sliding surface 24 are in contact with each other when the pressure of the purge liquid in the sliding device 1 is increased. The first sliding surface 14 of the fixed-side sliding member 12 and the second sliding surface 24 of the rotating-side sliding member 22 that are in a non-contact state due to the pressure of the purge liquid in the sliding device 1 ( Divergence state).

That is, when the pressure of the purge liquid in the sliding device 1 is increased, the load (between the fixed-side sliding member 12 and the rotating-side sliding member 22 (preferably, the pressure of the purge liquid in the sliding device 1) The total value of the pressing force by the magnet), the pressing force by the blood pressure, and the pressing force by the variable element is zero. At this time, the 1st sliding surface 14 and the 2nd sliding surface 24 will be in a non-contact state (separated state). The pressure of the purge liquid in the sliding device 1 at this time is referred to as “purge liquid separation pressure”. The purge pressure of the purge liquid is denoted by “Ps”. The dissociation pressure Ps of the purge liquid can be measured as follows. In the following description, “the divergence pressure of the purge solution” may be simply expressed as “the divergence pressure”.

FIG. 5 shows a change in pressure when the purge liquid circulation pump 212 is operated so as to send the purge liquid at a low flow rate (constant flow rate) with the flow rate adjustment valve 214 closed (the opening degree is zero). FIG. In FIG. 5, the horizontal axis indicates time, and the vertical axis indicates the pressure of the purge liquid in the sliding device 1.

In FIG. 5, when measuring the divergence pressure Ps, sliding is performed by sending the purge liquid at a low flow rate (constant) with the flow rate adjustment valve 214 closed (a state in which the opening degree is zero). The case where the operation of decreasing the pressure when the pressure of the purge liquid in the apparatus 1 rises and the pressure in the sliding apparatus 1 reaches the divergence pressure is repeated a plurality of times is shown.

When measuring the divergence pressure, first, the flow rate adjustment valve 214 is closed (opening is zero). In this state, if the purge liquid is continuously fed at a low flow rate (the flow rate is constant), the pressure of the purge liquid in the sliding device 1 increases in the process of continuously feeding the purge liquid. Thereafter, when the first sliding surface 14 of the stationary sliding member 12 in contact and the second sliding surface 24 of the rotating sliding member 22 are in a non-contact state (dissociated state), the stationary sliding is performed. The purge liquid leaks to the blood side existing on the outer peripheral side of the member 12 and the rotation-side sliding member 22, and the increase of the pressure of the purge liquid in the sliding device 1 stops and the pressure of the purge liquid starts to decrease rapidly. .

The pressure at this time (pressure when the pressure of the purge liquid in the sliding device 1 stops increasing and the pressure of the purge liquid starts to rapidly decrease) can be measured as the “separation pressure Ps”. Whether or not the pressure increase has stopped can be determined by monitoring the valve inlet side pressure P3 detected by the third pressure detector 217. Note that the pressure when the pressure of the purge liquid in the sliding device 1 stops increasing and the pressure of the purge liquid starts to rapidly decrease is “Pmax”, and the Pmax is the separation pressure Ps.

In measuring the separation pressure Ps, as shown in FIG. 5, the operation of increasing the pressure of the purge liquid in the sliding device 1 (the operation of gradually increasing the purge liquid pressure in the sliding device 1 to reach the separation). ) Is repeated a plurality of times, the pressure acquired each time (the pressure Pmax when the pressure of the purge liquid begins to drop rapidly) may be slightly different. In that case, the average of the pressures acquired every time (the pressure Pmax when the pressure of the purge liquid starts to drop rapidly) may be taken.

When the separation pressure Ps is measured as described above, the pressure of the purge liquid in the sliding device 1 is slightly lower than the separation pressure Ps (this pressure is referred to as “Ps ′”). In addition, at least one of the purge liquid circulation pump 212 and the flow rate adjustment valve 214 is controlled. Here, controlling the purge fluid circulation pump 212 means controlling the number of revolutions of the purge fluid circulation pump 212 as described above, and controlling the flow rate adjusting valve 214 means that the flow rate is adjusted. This means that the opening degree of the adjusting valve 214 is controlled.

Note that the pressure Ps ′ slightly lower than the divergence pressure Ps is preferably a pressure in the range of 85% to 95% of the divergence pressure Ps, and more preferably about 90% of the range. For example, when the pressure Ps ′ slightly lower than the divergence pressure Ps is 90% of the divergence pressure Ps, and the divergence pressure Ps is 28 KPa as described above, the pressure Ps ′ slightly lower than the divergence pressure Ps is It becomes approximately 25 KPa.

In the purge liquid circulation device 200 according to the embodiment, measuring the divergence pressure Ps and making the pressure of the purge liquid in the sliding device 1 become a pressure Ps ′ slightly lower than the divergence pressure Ps is: It is assumed that the purge liquid circulation unit control unit 220 automatically performs the operation.

Thus, when the purge liquid circulation unit controller 220 automatically measures the divergence pressure Ps and makes the pressure Ps ′ slightly lower than the measured divergence pressure Ps, the purge pressure The rotational speed of the purge liquid circulation pump 212 can be controlled by the control signal from the liquid circulation unit controller 220, and the opening degree of the flow rate adjustment valve 214 can be controlled.

Here, the control performed by the purge liquid circulation unit controller 220 will be described. First, the case where the deviation pressure Ps is measured will be described. When measuring the divergence pressure Ps, the purge liquid circulation knit control unit 220 controls the purge liquid circulation pump 212 so that the purge liquid circulation pump 212 is constant at a low rotation, and the flow rate adjustment valve 214 is controlled with a valve. Control to close (opening degree is zero).

Then, the valve inlet side pressure P3 detected by the third pressure detector 217 is monitored, the valve inlet side when the increase of the valve inlet side pressure P3 stops and the valve inlet side pressure P3 starts to decrease rapidly. The pressure P3 (“Pmax” in FIG. 5) is measured. The valve inlet side pressure P3 (Pmax) when the valve inlet side pressure P3 starts to drop rapidly is the pressure of the purge liquid in the sliding device 1 at this time, and this is defined as the separation pressure Ps. By doing in this way, deviation pressure Ps can be measured automatically.

When measuring the detachment pressure Ps, the purge liquid circulation pump 212 is configured to send the purge liquid at a constant flow rate with the flow rate adjustment valve 214 closed as described above. In the path 420, the pressure of the purge liquid is the same between the second pressure detection unit 216, the sliding device 1, and the third pressure detection unit 217. Therefore, the divergence pressure can be measured by detecting either the second pressure detection unit 216 or the third pressure detection unit 217.

Further, when setting the pressure Ps ′ slightly lower than the divergence pressure Ps, the purge liquid circulation unit controller 220 is configured so that the purge liquid pressure in the sliding device 1 is At least one of the purge liquid circulation pump 212 and the flow rate adjustment valve 214 is controlled so that the pressure Ps ′ is slightly lower than the deviation pressure Ps. That is, the purge liquid circulation unit controller 220 monitors the valve inlet side pressure P3 detected by the third pressure detector 217, and purges the valve inlet side pressure P3 so as to become a predetermined pressure based on the monitoring result. At least one of the liquid circulation pump 212 and the flow rate adjustment valve 214 is controlled.

Specifically, when the pressure Ps ′ that is slightly lower than the deviation pressure Ps is set to 25 KPa, the purge liquid circulation unit control unit 220 sets the target 25 KPa in the state in which the purge liquid is circulating. The value is set in the purge liquid circulation unit controller 220 as a value. As a result, the purge liquid circulation unit controller 220 controls at least one of the purge liquid circulation pump 212 and the flow rate adjustment valve 214 so that the pressure of the purge liquid in the sliding device 1 is 25 KPa.

At this time, the valve inlet side pressure P3 displayed on the third pressure detecting unit 217 is not the value of the pressure of the purge liquid in the sliding device 1 when the purge liquid circulates. Is also a low value. Accordingly, in order to temporarily set the pressure of the purge liquid in the sliding device 1 to 25 KPa, what value should be set for the valve inlet side pressure P3 is obtained, and the valve inlet side pressure P3 is set to the obtained value. Thus, at least one of the purge liquid circulation pump 212 and the flow rate adjustment valve 214 is controlled.

Specifically, when the pressure of the purge liquid in the sliding device 1 is to be set to 25 KPa, if the filter outlet pressure P2 detected by the second pressure detector 216 is 30 KPa, the third pressure detection The valve inlet side pressure P3 displayed in the part 217 may be 20 KPa. Therefore, in this case, the flow rate adjustment valve 214 may be controlled so that the valve inlet side pressure P3 becomes 20 KPa.

In this case, the filter outlet pressure P2 is kept constant at 30 KPa, and the valve inlet side pressure P3 is controlled so that the pressure of the purge liquid in the sliding device 1 is slightly lower than the separation pressure Ps. However, by controlling both the filter outlet pressure P2 and the valve inlet side pressure P3, the pressure of the purge liquid in the sliding device 1 is set to a pressure Ps ′ slightly lower than the deviation pressure Ps. May be.

By performing such control by the purge liquid circulation unit controller 220, the pressure of the purge liquid in the sliding device 1 can be set to a pressure Ps' that is slightly lower than the deviation pressure Ps.

FIG. 6 is a diagram schematically showing the state of the pressure of the purge liquid in the sliding device 1. By setting the pressure Ps ′ slightly lower than the divergence pressure Ps as a target value in the purge liquid circulation unit controller 220, the purge liquid pressure in the sliding device 1 is set to the target value in the purge liquid circulation unit controller 220. Thus, at least one of the purge liquid circulation pump 212 and the flow rate adjustment valve 214 is controlled. As a result, the pressure of the purge liquid in the sliding device 1 can be maintained at a pressure Ps' that is slightly lower than the deviation pressure Ps, as shown in FIG.

Thus, when the pressure of the purge liquid in the sliding device 1 is a pressure Ps ′ that is slightly lower than the detachment pressure Ps, when the rotation-side sliding member 22 is rotating, The purge liquid is forced to enter between the sliding surface 14 and the second sliding surface 24. At this time, the blood tends to enter between the first sliding surface 14 and the second sliding surface 24, but the purge liquid forcibly enters between the first sliding surface 14 and the second sliding surface 24. This makes it difficult for blood to enter between the first sliding surface 14 and the second sliding surface 24, so that the blood does not enter each of the fixed-side sliding member 12 and the rotating-side sliding member 22 in the sliding device 1. It can be reliably prevented from entering the inner peripheral side.

That is, since the pressure of the purge liquid in the sliding device 1 is a pressure Ps ′ slightly lower than the separation pressure Ps, the pressure of the purge liquid in the sliding device 1 is changed to an appropriate pressure (for example, sliding The pressure can be set higher than the pressure of blood existing on the outer peripheral surface of the device 1. For this reason, the purge liquid can be forcibly supplied between the first sliding surface 14 of the fixed-side sliding member 12 and the second sliding surface 24 of the rotating-side sliding member 22. A lubricating film can be stably formed between the first sliding surface 14 of the member 12 and the second sliding surface 24 of the rotation-side sliding member 22. As a result, blood can be prevented from entering the inner peripheral side of the sliding device 1, and the lubrication performance and sealing performance of the sliding device can be made higher than those of the conventional purge liquid circulating device.

FIG. 7 is a diagram schematically showing the relationship between the purge liquid and blood between the first sliding surface 14 and the second sliding surface 24.

FIG. 7A shows a case where at least one of the purge liquid circulation pump 212 and the flow rate adjustment valve 214 is controlled so that the pressure of the purge liquid in the sliding device 1 becomes a pressure Ps ′ slightly lower than the deviation pressure Ps. It is a figure which shows the relationship between the purge liquid and the blood between the 1st sliding surface 14 and the 2nd sliding surface 24. FIG.

FIG. 7B shows the first sliding surface 14 and the first sliding surface 14 when the purge liquid circulation pump 212 delivers the purge liquid at a constant pressure (30 KPa) and the flow rate adjustment valve 214 is fully opened. It is a figure which shows the relationship between the purge liquid and the blood between 2 sliding surfaces. When the purge liquid circulation pump 212 is sending out the purge liquid at 30 KPa, the pressure of the purge liquid in the sliding device 1 is about 15 KPa as described above, and therefore is a pressure lower than the pressure Ps ′. ing.

7 (a) and 7 (b), the purge solution is shown in light gray and the blood is shown in black. 7A and 7B show the relationship between the purge liquid and blood on the first sliding surface 14, and the second sliding surface 24 is not shown. Actually, there is a second sliding surface 24 facing the first sliding surface 14. 7 (a) and 7 (b) show the relationship between the purge liquid and blood on the first sliding surface 14, and therefore other components (the first sliding surface 14) ( For example, the rotation shaft 28 and the like are not shown.

As shown in FIG. 7A, at least one of the purge liquid circulation pump 212 and the flow rate adjustment valve 214 is set so that the pressure of the purge liquid in the sliding device 1 becomes a pressure Ps ′ slightly lower than the deviation pressure Ps. When controlled, the pressure of the purge liquid in the sliding device 1 becomes such a pressure that the purge liquid forcibly enters between the first sliding surface 14 and the second sliding surface 24.

Therefore, the space between the first sliding surface 14 and the second sliding surface 24 is almost occupied by the purge liquid. In this state, even if blood tries to enter between the first sliding surface 14 and the second sliding surface 24, the purge is forced to enter between the first sliding surface 14 and the second sliding surface 24. Due to the pressure of the liquid, it can enter only a small portion near the outer periphery of the first sliding surface 14 and the second sliding surface 24. Thereby, blood can be reliably prevented from entering the inner peripheral side of the sliding device 1.

On the other hand, in FIG. 7B, the pressure of the purge liquid in the sliding device 1 is not so high compared to the case of FIG. Sometimes it comes in.

By the way, as shown in FIG. 7A, after a part of the purge liquid passes between the first sliding surface 14 and the second sliding surface 24, the fixed-side sliding member 12 and the rotation-side sliding member are moved. Although it may reach the outer peripheral side of the moving member 22 and enter the blood, as described above, since the purge solution is made of water, physiological saline, or the like, there is no particular problem even if it enters the blood. .

As described above, according to the purge liquid circulation apparatus 200 according to the embodiment, the pressure of the purge liquid in the sliding apparatus 1 is slightly lower than the divergence pressure Ps. The pressure of the purge liquid in the device 1 can be set to an appropriate pressure (for example, a pressure that is surely higher than the pressure of blood existing on the outer peripheral surface of the sliding device 1). For this reason, the purge liquid can be forcibly supplied between the first sliding surface 14 of the fixed-side sliding member 12 and the second sliding surface 24 of the rotating-side sliding member 22. A lubricating film can be stably formed between the first sliding surface 14 of the member 12 and the second sliding surface 24 of the rotation-side sliding member 22. As a result, blood can be prevented from entering the inner peripheral side of the sliding device 1, and the lubrication performance and sealing performance of the sliding device can be made higher than those of the conventional purge liquid circulating device.

As mentioned above, although this invention was demonstrated based on said embodiment, this invention is not limited to said embodiment. The present invention can be implemented in various modes without departing from the spirit thereof, and for example, the following modifications are possible.

(1) The control method for setting the pressure of the purge liquid in the sliding device 1 to be a pressure Ps ′ slightly lower than the deviation pressure Ps is the control method described in the above embodiment, that is, the pressure Ps ′. Is set as a target value in the purge liquid circulation unit control unit 220. In the purge liquid circulation unit control unit 220, the purge liquid circulation pump 212 and the flow rate adjustment are performed so that the pressure of the purge liquid in the sliding device 1 becomes the target value. The control method is not limited to controlling at least one of the valves 214, and the following control method may be employed.

That is, the rotational speed of the purge liquid circulation pump and the opening degree of the flow rate adjustment valve 214 are acquired so that the pressure of the purge liquid in the sliding device 1 becomes a pressure Ps ′ slightly lower than the deviation pressure Ps. At least one of the number of revolutions of the purge liquid circulation pump and the opening of the valve is set in the purge liquid circulation unit controller 220.

Accordingly, the purge liquid circulation unit controller 220 adjusts the purge liquid circulation pump and the flow rate based on at least one of the rotation speed of the purge liquid circulation pump and the opening of the valve set in the purge liquid circulation unit controller 220. At least one of the valves 214 is controlled. Even with such control, the pressure of the purge liquid in the sliding device 1 can be set to a pressure Ps' that is slightly lower than the deviation pressure Ps. For example, when the divergence pressure Ps is updated for some reason, the rotational speed of the purge fluid circulation pump and the valve opening are set so that the pressure Ps ′ is slightly lower than the updated divergence pressure Ps. Just set it again.

(2) In the above embodiment, the case where the measurement of the divergence pressure Ps and the setting of the pressure Ps ′ slightly lower than the divergence pressure is automatically performed by the purge liquid circulation unit control unit 220 has been described. The measurement of Ps and the setting of the pressure Ps ′ slightly lower than the divergence pressure can be manually adjusted by the operator while monitoring the third pressure detector 217. .

(3) In the above embodiment, as control for setting the filter outlet side pressure P2 to a predetermined pressure (for example, 30 KPa), the purge liquid circulation unit controller 220 monitors the filter outlet side pressure P2. However, although the purge liquid circulation pump 212 is controlled, the present invention is not limited to this. For example, the number of revolutions of the purge liquid circulation pump 212 necessary for the filter outlet side pressure P2 to become a predetermined pressure (for example, 30 KPa) is set in the purge liquid circulation unit control unit 220, and the purge liquid circulation unit control unit 220 is set. The purge liquid circulation pump 212 may be controlled so that the purge liquid supply pump 212 operates at a set rotation speed.

(4) The number, material, shape, position, size, and the like of the constituent elements described in the above embodiment are merely examples, and can be changed within a range not impairing the effects of the present invention.

(5) In the sliding device 1 in the above-described embodiment, the silicon carbide sliding members (fixed-side sliding member and rotating-side sliding member) are made of silicon oxide water before being assembled as a sliding device. A “familiarizing process” that is a process of forming a Japanese product on the sliding surface may be performed. With such a configuration, the sliding surface of the sliding member made of silicon carbide has “a highly hydrophilic silicon oxide hydrate” by a tribochemical reaction. For this reason, blood becomes difficult to adhere to the sliding surface, and as a result, sliding resistance when used in an aqueous liquid containing blood is reduced compared to a sliding device that does not perform the “familiarization treatment”. Is possible.

(6) In the above embodiment, the purge fluid circulation device in the blood pump has been described. However, the present invention is not limited to the technical field of the blood pump used in the auxiliary artificial heart system. The present invention can also be applied to the technical field of pumps that handle aqueous liquids (blood component-containing liquids) in which components (blood cell components, plasma proteins, etc.) are dispersed.

(7) In the above embodiment, the divergence pressure is slid by continuously feeding the purge liquid at a low flow rate (with a constant flow rate) in a state where the flow rate adjustment valve 214 is closed (a state where the opening degree is zero). Although it was calculated | required as a pressure when the raise of the pressure of the purge liquid in the apparatus 1 stops and the pressure of the said purge liquid begins to fall rapidly, a deviation pressure is not restricted to calculating | requiring in this way. It can also be determined by the method.

First, the filter outlet pressure P2 is set to a predetermined pressure (for example, 30 KPa), and the purge liquid is circulated with the opening of the flow rate adjustment valve 214 fully opened. In this state, when the valve opening of the flow rate adjustment valve 214 is gradually reduced, the pressure of the purge liquid in the sliding device 1 increases. Thereafter, when the first sliding surface 14 of the fixed-side sliding member 12 in contact and the two sliding surfaces 24 of the rotating-side sliding member 22 are in a non-contact state (dissociated state), in the sliding device 1 The increase in the pressure of the purge liquid stops and the pressure of the purge liquid starts to decrease rapidly. The pressure at this time (pressure when the pressure of the purge liquid in the sliding device 1 stops increasing and the pressure of the purge liquid starts to rapidly decrease) is defined as “Pmax”.

Here, in the state where the purge liquid is circulating, the pressure of the purge liquid in the sliding device 1 is approximately an average value of the valve inlet side pressure P3 and the filter outlet side pressure P2. For example, it is assumed that the valve inlet side pressure P3 (P3 = Pmax) when the pressure of the purge liquid in the sliding device 1 stops increasing is 26 KPa. The divergence pressure Ps at this time can be obtained as (30 kPa + 26 kPa) / 2 = 28 kPa.

(8) The method as shown in (7) above can measure the divergence pressure without stopping the circulation of the purge solution. Therefore, the divergence pressure can be measured even after the blood pump 110 is implanted in the body. It becomes. Thus, the divergence pressure Ps can be periodically performed, for example, once a day at a predetermined time, or can be performed at the timing when an alarm for notifying some abnormality is generated. Here, for example, some abnormality can be exemplified when the power consumption suddenly increases. Further, since the measured divergence pressure may be different depending on the situation at that time, it can be constantly updated to the latest divergence pressure.

DESCRIPTION OF SYMBOLS 1 ... Sliding device, 10 ... Fixed part, 12 ... Fixed side sliding member, 14 ... 1st sliding surface, 20 ... Rotating part, 22 ... Rotating side sliding Member 24 ... second sliding surface 26 ... impeller 28 ... rotating shaft 30 ... rotation drive device 32 ... blood pump chamber 40 ... purge solution in blood pump Circulation path, 100 ... assisting artificial heart system, 110 ... blood pump, 120, 130 ... artificial blood vessel, 200 ... purge fluid circulation device of blood pump, 210 ... purge fluid circulation unit, 211 ... Purge fluid reservoir (reservoir), 212 ... Purge fluid circulation pump, 213 ... Filter, 214 ... Flow rate adjusting valve, 215 ... First pressure detector, 216 ... Second Pressure detection unit, 217... Third pressure detection unit, 218. In-unit feed-side circulation path, 219... In-unit return-side circulation path, 220... Purge liquid circulation unit controller, 400... Connection cable, 410. Side tube, 412 ... Return side tube, 420 ... Purge solution circulation path

Claims

A fixed-side sliding member having an annular first sliding surface and a rotating-side sliding member having an annular second sliding surface provided inside a blood pump embedded in a user's body, A slide used in a state where the first sliding surface and the second sliding surface are opposed to each other and each outer peripheral side of the fixed-side sliding member and the rotating-side sliding member is in contact with blood. A moving device;
A purge fluid circulation unit that circulates a purge fluid having a function of maintaining lubrication performance, cooling performance, and sealing performance inside the blood pump through each inner peripheral side of the fixed-side sliding member and the rotating-side sliding member;
A purge liquid circulation path configured to return from the purge liquid circulation unit to the purge liquid circulation unit through the inner peripheral sides of the fixed side sliding member and the rotation side sliding member;
A purge fluid circulation device for a blood pump comprising:
The purge liquid circulation unit includes:
A purge liquid reservoir for storing the purge liquid;
A purge liquid circulation pump that applies a unidirectional movement force to the purge liquid stored in the purge liquid storage section;
Adjusting the flow rate of the purge liquid provided near the purge liquid inlet of the purge liquid storage section and returning to the purge liquid storage section through the inner peripheral sides of the fixed side sliding member and the rotation side sliding member A flow control valve capable of
A purge fluid circulation device for a blood pump, comprising:
The purge solution circulating apparatus for a blood pump according to claim 1,
The first sliding surface and the second sliding surface that are in contact with each other are brought into a non-contact state by the pressure of the purge liquid existing on each inner peripheral side of the fixed side sliding member and the rotation side sliding member. When the pressure of the purge liquid is the divergence pressure of the purge liquid,
The purge fluid circulation pump and the purge fluid circulation pump so that the pressure of the purge fluid existing on each inner peripheral side of the stationary sliding member and the rotating sliding member is slightly lower than the divergence pressure of the purge fluid. A purge fluid circulation apparatus for a blood pump, further comprising a purge fluid circulation unit controller having a function of controlling at least one of the flow rate adjustment valves.
The purge solution circulating apparatus for a blood pump according to claim 2,
The purge fluid circulation unit controller
The purge that exists on each inner peripheral side of the fixed-side sliding member and the rotating-side sliding member in the process in which the purge fluid circulation pump continues to feed the purge fluid at a constant flow rate with the flow rate adjusting valve closed. A purge fluid circulation device for a blood pump, further comprising a function of measuring the pressure of the purge fluid when the rise of the fluid pressure stops and the pressure of the purge fluid begins to rapidly decrease as the divergence pressure.
The purge solution circulating apparatus for a blood pump according to claim 2 or 3,
The purge liquid circulating apparatus for a blood pump, wherein the pressure slightly lower than the divergence pressure of the purge liquid is a pressure in a range of 85% to 95% of the divergence pressure.
The purge solution circulating device for a blood pump according to any one of claims 1 to 4,
The purge liquid circulation unit includes:
A filter provided on the downstream side of the purge liquid circulation pump for removing unnecessary substances contained in the purge liquid circulating in the purge liquid circulation path;
A first pressure detector for detecting the pressure of the purge liquid in the vicinity of the purge liquid inlet of the filter;
A second pressure detector for detecting the pressure of the purge liquid in the vicinity of the purge liquid outlet of the filter;
A third pressure detector for detecting the pressure of the purge liquid in the vicinity of the purge liquid inlet of the flow rate adjusting valve;
A purge fluid circulation device for a blood pump, further comprising:
The purge solution circulating apparatus for a blood pump according to any one of claims 1 to 5,
The purge solution circulating apparatus for a blood pump, wherein at least one of the fixed-side sliding member and the rotating-side sliding member is made of silicon carbide.
The purge solution circulating apparatus for a blood pump according to any one of claims 1 to 6,
An antithrombotic treatment is applied to each outer periphery of the stationary side sliding member and the rotating side sliding member, and the purge solution circulating apparatus for a blood pump is characterized in that:
A blood pump embedded in the body, an artificial blood vessel for connecting the blood pump and the blood flow of the heart, a blood pump control device for driving and controlling the blood pump, and a purge liquid circulating in the blood pump An auxiliary artificial heart system comprising a blood pump purge fluid circulation device for
The auxiliary artificial heart system according to any one of claims 1 to 7, wherein the purge solution circulating device of the blood pump is the purge solution circulating device of the blood pump.