JPH02102638A - Fluid pressure measuring instrument - Google Patents

Abstract

PURPOSE:To execute exact pressure measurement for a long time by joining a press transducer and a pressure dome, engaging a first engaging part and a second engaging part, elastically deforming a part of the pressure dome and pressing the diaphragm of the pressure transducer by the thin film of the pressure dome. CONSTITUTION:A transducer 14 is constituted so that pressure to be operated to a diaphragm 54 can be detected by a piezoelectric transformer to be housed in the internal part of a cylindrical body 50 and an electric signal can be generated. When the force is added to projecting parts 36 and 36 in a lower direction and both the diaphragm 54 and a membrane 34 are engaged in a condition that the membrane 34 of a pressure dome 12 is abutted to the diaphragm 54 of the transducer 14, an outer frame part 20 is deformed by bending. On the other hand, the outer frame part 20 tries to be restored to an original shape and as a result, the membrane 34 is pressurized contact with the diaphragm 54 of the transducer 14 by prescribed pressing force. Consequently, the contact pressure of the membrane 34 and disphragm 54 is held constant. Since this pressing operation is based on the elastic deformation of the whole outer frame part 20, connection can be executed for a long time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fluid pressure measuring device suitable for use in invasive blood pressure measurement lines, etc. When integrated, the outer frame of the pressure dome deforms slightly and applies a pressing force to the fitting area of the pressure transducer, so that the thin film stretched over the pressure dome and the diaphragm of the pressure transducer are The present invention relates to a fluid pressure measuring device that is capable of maintaining a constant contact pressure over a long period of time and also capable of accurately measuring pressure over a long period of time.

[Background of the Invention] In recent years, an invasive blood pressure measurement system that can monitor a patient's blood pressure in real time has been developed and is widely used in actual medical practice. Specifically, for example, if there is a need to continuously monitor a patient's blood pressure during a surgical procedure;
This invasive blood pressure measurement system is used.

In general, this type of invasive blood pressure measurement system uses a catheter inserted into a patient's blood pressure measurement site, a pressure transmission line consisting of a pressure transmission tube, etc., and detects the pressure transmitted via this pressure transmission line. It consists of a pressure measuring device and a monitor device that displays or records the pressure value detected by the pressure measuring device.

Among these, as a pressure measuring device, one in which a pressure dome and a pressure transducer are integrated has been employed. In this case, a cavity partitioned by a thin film is defined within the pressure dome, and the pressure of a liquid such as saline introduced into this cavity presses the diaphragm of the pressure transducer in contact with the thin film.

A pressure transducer converts the pressure experienced by the diaphragm into an electrical signal.

For such pressure measurement devices, the error in the measurement value also depends on the contact pressure between the thin film of the pressure dome and the diaphragm of the pressure transducer, so in order to measure accurate pressure, it is necessary to attach the pressure dome to the pressure transducer. In this case, the contact pressure must be maintained appropriately.

Conventionally, a screw mechanism has been employed to integrate the pressure dome and pressure transducer.

That is, a first screw portion is provided in the main body portion of the pressure dome,
On the other hand, a second screw portion is provided on the pressure transducer side. Then, the first screw portion and the second screw portion are screwed together to integrate the pressure dome and the pressure transducer. However, depending on how the pressure dome is screwed onto the pressure transducer, the contact pressure between the thin film of the pressure dome and the diaphragm of the pressure transducer may not be uniform, and to deal with this, it is necessary to adjust the zero point of the monitor device prior to measurement. was there.

For such a screw-in type, Japanese Patent Application Laid-Open No. 62-211
A type disclosed in Publication No. 043 has been proposed. In this method, an elastic tongue piece is provided on the cylindrical peripheral wall of the pressure dome body, and a groove is formed inside the tongue piece in a circumferential direction, extending outward from the periphery of the pressure receiving surface of the pressure transducer. By guiding the existing protrusion into the groove, the two are integrally engaged.

That is, in this type of joining method, the pressure dome is pressed against the pressure transducer using the elastic deformation of the tongue piece, thereby ensuring contact pressure between the thin film of the pressure dome and the diaphragm of the pressure transducer.

However, since the portion of the tongue pressing against the pressure transducer is small, the elasticity of the tongue deteriorates over time, resulting in a decrease in the contact pressure between the thin film and the diaphragm. It has been pointed out.

[Object of the Invention] The present invention has been made to overcome the above-mentioned disadvantages, and provides a groove portion into which a protrusion provided on the main body of the transducer fits into the inner surface of the cylindrical outer frame of the pressure dome. When the protrusion of the transducer is engaged with the outer frame of the pressure dome side and the two are integrated, elastic deformation is caused in the entire outer frame of the pressure dome, and as a result, the pressure dome An object of the present invention is to provide a fluid pressure measuring device configured to constantly maintain a constant contact pressure between a thin film of a pressure transducer and a diaphragm of a pressure transducer.

Means for Accomplishing the Objects In order to achieve the above objects, the present invention provides a pressure dome for introducing fluid into a cavity inside a body and transmitting the pressure through a thin film sealing the cavity; a pressure transducer comprising a diaphragm for receiving pressure from a thin membrane, and having a first engaging portion integrally with the body of the pressure dome;
On the other hand, a second engaging part is provided on the main body of the pressure transducer, and the pressure transducer and the pressure dome are joined together, and the first engaging part and the second engaging part are engaged to make a part of the pressure dome elastic. It is characterized in that upon deformation, the thin membrane of the pressure dome presses against the diaphragm of the pressure transducer.

[Embodiments] Next, preferred embodiments of the fluid pressure measuring device according to the present invention will be described in detail with reference to the accompanying drawings.

In FIG. 1, reference numeral 10 designates a fluid pressure measuring device according to the invention. This fluid pressure measuring device 1 basically consists of a pressure dome 12 and a pressure transducer 14. FIG. 2 is a longitudinal sectional view of the pressure dome 12. As can be easily understood, the pressure dome 12 includes a cylindrical main body 16 that is open at one end, and a cylindrical outer frame that surrounds the main body 16 and is integrated at connecting parts 18a and 18b. 20.

Extending outwardly from one end of the body portion 16 are tube members 24,25 each defining a passageway 22,23. Main body part 16
Although the pipe members 24 and 25 are integrally molded in this case, it goes without saying that they may be constructed as separate members. passages 22 coaxially formed in the tube members 24 and 25, respectively;
communicates with a cavity 26 defined inside the cylindrical body portion 16. A circumferential groove 28 is defined on the end side of the open portion of the main body portion 16 . That is, it is divided into an inner end surface 30 and an outer end surface 32 with this circumferential groove 28 in between. In this case, the inner end surface 30 and the outer end surface 32 have different heights, and as shown in FIG. 2, when viewed from the main body 16,
The inner end surface 30 is selected to be longer in cross section than the outer end surface 32. A membrane 34 as a thin film is stretched in contact with the inner end surface 30 and welded to the outer end surface 32 so as to completely seal the cavity 26 defined within the cylindrical main body portion 16. In this way, by specifically providing a step between the inner end surface 30 and the outer end surface 32, the flatness of the membrane 34 at the inner end surface 30 is maintained so as not to be loosened or distorted.

The membrane 34 is made of polytetrafluoroethylene and has a thickness of 0.20 mm and has a large number of pores with an average diameter of 0.07 μm in order to provide air removal properties. In this case, the material is not limited to polytetrafluoroethylene, but may be polyethylene, polypropylene, or a copolymer of ethylene and tetrafluoroethylene. Of course, even when such a material is used, a large number of pores with a diameter of 0.07 μm are formed.

On the other hand, the outer frame portion 20 is made of flexible synthetic resin and is molded into the cylindrical shape shown in the figure. A pair of convex portions 36, 36 are formed on the outer surface of the outer frame portion 20 on opposite sides to each other and bulge outward.

1 and 2 show a structure provided inside the protrusion 36, 36 to engage with a protrusion (described later) provided on the transducer 14. That is, a guide groove 40 for guiding the protrusion of the transducer 14.
40 is installed in the vertical direction of the convex portion. This guide groove 4
0.40 for engaging the protrusion and pressing the dome against the transducer, and extending from the region where this slope 844.44 terminates toward the stepped portion 42.42. A flat portion 46.46 is provided, and the ramped portion 44.44 terminates in a detent 47.47 which engages the protrusion.

Next, the transducer 14 will be explained.

In FIG. 1, transducer 14 includes a cylindrical body 50 and a housing body 52 integral with cylindrical body 50. In FIG. A diaphragm 54 that receives pressure is stretched on the upper surface of the cylindrical body 50.
A piezoelectric transducer housed inside the cylindrical body 50 detects the pressure acting on the cylindrical body 50 and generates an electrical signal. The electrical signal is transmitted to the housing-like body 52.
For example, the information is outputted and displayed on a display monitor from a cable 56 extending from the end of the screen. Further, a pair of protrusions 58, 58 are formed at predetermined positions above the side surface of the cylindrical body 50, oriented outward from each other.

The fluid pressure measuring device according to the present invention is basically constructed as described above.Next, its operation and effects will be explained.

The pressure dome 12 is integrally assembled to the pressure transducer 14 in the manner described above.

That is, as shown in FIG. 1, the projections 36.36 provided on the outer frame 20 of the pressure dome 12 and the projections 58.58 provided on the cylindrical body 50 of the pressure transducer 140 are aligned. Then, the protrusion 58.58 is connected to the protrusion 3.
6.36, the pressure dome 12 is placed over the pressure transducer 14 so as to fit into the inner guide groove 40.40. Then, as shown in FIG. 3, the pressure dome 12 is slightly rotated to the right to firmly integrate the two.

In this case, the projection 58.5 of the pressure transducer 14
8 is a convex portion 36.3 of the outer frame portion 20.20 of the pressure dome 12
6, the inclined part 44, the detent 47, and the flat part 46 are moved in this order. More specifically, first, with the diaphragm 54 of the transducer and the membrane 34 of the pressure dome 12 in contact, the protrusion 58.58
comes into contact with the inclined part 44, 44 and as the rotation progresses, the protruding part 5
8.58 presses this inclined portion 44.44 downward, and therefore the convex portion 36.36 and the outer frame 2 integral therewith
0 is in a bent state with a shape that is slightly displaced downward. As the rotation progresses further, the protrusion 58.58 overcomes the detent 47 and reaches the flat part 46.46, and almost simultaneously abuts against the stepped part 42, so rotation stops and the protrusion 58.58 reaches the flat part 46.46. Take a seat. When seated, the protrusions 58,58 naturally press downwardly against the flats 46,46, so that the membrane 34 of the pressure dome 12 is in a constant position against the diaphragm 54 of the transducer, as seen in FIG. This means that they are pressed together by force.

That is, the membrane 34 of the pressure dome 12 (which is the inner end surface of the pressure dome 12 because it is actually in contact with pressure) is in contact with the diaphragm 54 of the transducer 14, and in this state, the convex portion 36. Since the two are engaged by applying force, the outer frame portion 20 is deformed by bending. On the other hand, as a result of trying to restore the outer frame portion 20 to its original shape, the membrane 34 is attached to the pressure transducer 14.
diaphragm 54 with a predetermined pressing force. As a result, the contact pressure between the membrane 34 and the diaphragm 54 is maintained constant. This pressing action is applied to the outer frame portion 20.
It is understood that it is sustainable over a long period of time since it is based on overall elastic deformation.

Therefore, when the fluid pressure measuring device IO is actually incorporated into a visual blood pressure measurement system, physiological saline is introduced into the cavity 26 in the pressure dome 12 from the passage of the tube member 24 and led out from the passage 23 of the tube member 25. The diaphragm 54 of the pressure transducer 14 in contact with the membrane 34 is pressed by the action of the pressure. At this time, membrane 34
Since the contact pressure between the diaphragm 54 and the diaphragm 54 is maintained appropriately, it becomes possible to perform accurate pressure measurements.

[Effects of the Invention] As described above, according to the present invention, when a pressure transducer and a pressure dome are engaged and integrated, the outer frame of the pressure dome is slightly deformed, and the elastic force based on the deformation is reduced. An additional action is applied to maintain an appropriate contact pressure between the diaphragm of the pressure transducer and the membrane of the pressure dome. Therefore, the contact pressure does not change due to long-term use, and therefore, it is possible to avoid the trouble of adjusting the zero point of the measuring device for each measurement, making it possible to measure pressure efficiently and accurately. Effects can be obtained.

Although the present invention has been described above with reference to preferred embodiments, the present invention is not limited to these embodiments.
Of course, various improvements and changes in design are possible without departing from the gist of the present invention.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a pressure dome and a pressure transducer constituting a fluid pressure measuring device according to the present invention, Fig. 2 is a longitudinal sectional view of the pressure dome, and Fig. 3 is a top view of the fluid pressure measuring device. FIG. 4 is a longitudinal cross-sectional view of the pressure dome and pressure transducer integrated. lO...Fluid pressure measuring device 12...Pressure dome 14...Pressure transducer 16...Main body part 20...Outer frame part 26
...Cavity 34...Membrane 36
...Convex portion 40...Guide groove 44...Slope portion 50
... Cylindrical body 52 ... Housing-like body 5
4...Diaphragm 58...Protrusion FIG
,3

Claims (4)

[Claims] (1) The body of the pressure dome consists of a pressure dome that introduces fluid into a cavity inside the main body and transmits the pressure through a thin film that seals the cavity, and a pressure transducer that includes a diaphragm that receives pressure from the thin film. A first engaging portion is provided integrally with the main body of the pressure transducer, and a second engaging portion is provided on the main body of the pressure transducer, and the pressure transducer and the pressure dome are joined to engage the first engaging portion and the second engaging portion. A fluid pressure measuring device characterized in that a thin film of the pressure dome presses a diaphragm of a pressure transducer by engaging the parts of the pressure dome and elastically deforming a part of the pressure dome. (2) In the device according to claim 1, the first engaging portion is provided on the outer frame made of a flexible member that is integral with the main body of the pressure dome, and the second engaging portion is provided on the outer frame of the pressure transducer main body. 1. A fluid pressure measuring device comprising one or more protrusions arranged so as to direct. (3) In the device according to claim 1 or 2, the first engaging portion provided on the outer frame of the pressure dome main body is one or more convex portions provided on the outer frame so as to bulge outward. The pressure transducer is characterized in that the pressure transducer is provided with an inclined part and a flat part to which the protruding part, which is the second engaging part, engages, and a guide groove that guides the protruding part to the inclined part. Fluid pressure measurement device. (4) The fluid pressure measuring device according to claim 2 or 3, wherein the first engaging portion has a detent.