JP2007278148A - Fixed volume type electromagnetic pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnetic pump capable of reducing dead space in a pump chamber as much as possible and providing fixed delivery quantity by preventing reverse flow of fluid due to influence of back pressure. <P>SOLUTION: In the pump chamber, a top surface of a valve element of a delivery valve forming a surface thereof and a pump chamber side surface of a valve seat are made flush with each other. A bottom surface of the valve element forming another surface of the pump chamber and a pump chamber side surface of the valve seat are made flush with each other. Consequently, dead space of the pump chamber is reduced. Although fluid pressurized in the pump chamber is made flow out to an outer apparatus from a plunger drive space, a reverse flow prevention valve preventing reverse flow is provided in the delivery passage connected to the plunger drive space. Consequently, influence of back pressure is eliminated and fixed delivery quantity is maintained. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an in-line type electromagnetic pump, and more particularly to an electromagnetic pump capable of stably supplying a constant capacity.

  In the electromagnetic pump, the plunger is reciprocated by a pulse current applied to the solenoid, whereby the pressure in the pump chamber fluctuates, and the pump action is performed by the cooperation of the pair of check valves. The liquid to be transferred in such an electromagnetic pump is petroleum, chemicals, etc., and is sent out smoothly due to its incompressibility. However, when air is mixed, it is because of the compressibility of the air. There has been a problem that an air lock (vapor lock), which is a phenomenon in which a predetermined negative pressure or positive pressure does not occur in the pump chamber and the pair of check valves do not operate, occurs.

  Therefore, as a countermeasure, it has been proposed to deal with it by reducing the dead space in the pump chamber (a value obtained by subtracting the liquid discharge amount from the volume of the pump chamber) as much as possible. That is, by increasing the compression ratio, an inconvenience due to mixed air is to be solved.

Patent Document 1 is proposed based on such a technical idea. For this purpose, a small-sized intake valve body 18 which is attached to the downstream end portion of the discharge plunger 11 and engages with the intake valve seat 17, and the back of the intake valve body of the intake valve cylinder 19 which houses the small intake valve body 18 are opposed. A discharge valve seat 49 provided at the downstream end of the cylinder 15 to which the discharge plunger 11 reciprocates is provided with a suction valve body and a plurality of small projections 48 that support and form a fluid when opened. A discharge valve body 20 is attached to the main body. Thereby, the volumetric efficiency is increased and the air lock by the dissolved air is prevented.
JP-A-11-218076

  However, even in the positive displacement electromagnetic pump shown in Patent Document 1, the valve cylinder port 47 and the suction valve chamber 46 connected to the pump chamber 50 are dead spaces. Leaving the possibility of happening.

  In addition, if there is pressure from an external device (pressurized back pressure) in the discharge passage, backflow into the plunger drive space or pump chamber occurs through the discharge passage, and the discharge amount is not uniform and the discharge amount is There is a risk that the discharge amount becomes zero in the worst case.

  In view of this, an object of the present invention is to reduce the dead space in the pump chamber as much as possible by renewing the structure and arrangement of not only the intake valve but also the discharge valve in order to prevent air lock caused by air dissolved in the fluid.

  Then, this invention makes it a subject to prevent a fluid flowing backward from the influence of the back pressure from an external apparatus, and to continue constant discharge amount.

  A constant displacement electromagnetic pump according to the present invention includes a cylinder provided between a suction passage and a discharge passage, a piston reciprocating in the cylinder, a discharge valve provided in the piston, and a discharge valve. An electromagnetic pump having a suction valve provided on the upstream side, a plunger and a coil for reciprocating the piston, and performing a pump action by changing a volume of a pump chamber composed of the suction valve, the discharge valve, and the cylinder The discharge valve is composed of a valve body and a valve seat, the top surface of the valve body is flush with the side of the pump chamber of the valve seat, and the suction valve is upstream of the discharge valve, It consists of a valve body and a valve seat, and is made to be flush with the bottom surface of the valve body and the surface of the valve seat on the pump chamber side.

  As a result, both the piston side and the non-piston side constituting the pump chamber are flush with each other, contributing to the reduction of dead space and bringing the piston stroke (top dead center position) closer to the intake valve. Can do.

  The present invention also provides a cylinder provided between the suction passage and the discharge passage, a piston reciprocating in the cylinder, a discharge valve provided in the piston, and an upstream side of the discharge valve. An electromagnetic pump including a suction valve, a plunger for reciprocating the piston, and a coil, and performing a pump action by changing a volume of a pump chamber configured by the suction valve, the discharge valve, and the cylinder. Comprises a valve body and a valve seat so that the top surface of the valve body is flush with the side of the pump chamber of the valve seat, and the suction valve is upstream of the discharge valve, The plunger is flush with the bottom surface of the valve body and the surface of the valve seat on the pump chamber side, and the plunger is disposed in the plunger drive space formed on the downstream side of the discharge valve. When the coil is not energized, the return sp And the downstream end thereof is seated on the valve seat, and the upstream end thereof is opposed to the right magnetic cylinder with a predetermined distance and is attracted when the coil is excited. The upstream end of the plunger is in contact with the right magnetic cylinder so as to make a constant stroke, and the backflow prevention valve is provided in the direction opposite to the fluid flow direction in the discharge passage communicating with the drive space of the plunger. (Claim 2).

  As a result, the upstream end and the downstream end of the plunger are in contact with the fixed side to be regulated, and the fixed stroke is transmitted to the piston. Then, since the backflow prevention valve is provided in the discharge passage, the pressure in the plunger drive space drops due to the movement of the piston at the beginning of the ascent process (due to the time lag of opening the discharge valve). Is closed to prevent backflow. That is, back pressure (pressure from an external device) is not applied to the discharge valve. If back pressure is applied, the opening time of the discharge valve is delayed or remains closed, and pumping cannot be performed.

  Then, when the piston rises and the pressure in the pump chamber rises and a pressure difference from the plunger drive space is generated, the discharge valve opens and the fluid flows out into the plunger drive space. At the same time, the pressure in the space rises, the backflow prevention valve is opened due to the pressure difference, and the fluid flows out to the external device.

  If the pressure inside the plunger drive space decreases and becomes equal to the back pressure after the top dead center is passed and the lowering process is performed, the check valve is closed. Since it is important to close the backflow prevention valve early in order to prevent backflow, and therefore it can be adjusted by the seat diameter (seat hole) of the valve seat and the spring load, the pressure loss in this portion is small. The constant discharge amount is maintained by such a configuration action.

  A stop valve is provided at the downstream end of the plunger (Claim 3), and the cushion function and the internal liquid are prevented from flowing out when the pump is stopped.

  Since the cylinder is made of polyetheretherketone (Claim 4), it is possible to reduce elution of ions in the transferred liquid.

  As described above, according to the first aspect of the present invention, both the piston side and the non-piston side of the pump chamber are flush with each other, contributing to the reduction of the dead space of the pump chamber, thereby increasing the compression ratio. . Further, the discharge valve at the tip of the piston is also flush and the suction valve is also flush, so that the tip of the piston can be brought as close as possible to the suction valve, and the volumetric efficiency can be improved.

  According to the invention of claim 2, the plunger is reciprocated by a constant stroke with the upstream end and the downstream end coming into contact with the fixed side, and this movement is transmitted to the piston to output a constant capacity. And by having a backflow prevention valve, it can be made not to receive the influence of the pressure (back pressure) which the external apparatus provided downstream from a discharge passage has. In other words, the backflow prevention valve is opened and closed by the pressure difference between the plunger drive space pressure and the external device, so that backflow is prevented and the opening of the discharge valve is not affected, and the desired capacity (constant discharge amount) can be maintained. it can.

  According to the invention of claim 3, it is preferable to provide a shut-off valve at the downstream end of the plunger, thereby preventing contact vibration and noise, and preventing the internal fluid from flowing out when the pump is stopped. Yes.

  According to a fourth aspect of the present invention, the cylinder is preferably manufactured from polyether ether ketone (PEEK), ion elution can be minimized in the liquid, and the cylinder can be used for transferring a fluid such as a fuel cell. Can do.

  Embodiments of the present invention will be described below with reference to the drawings.

  1 and 2, a constant displacement electromagnetic pump 1 is shown, and a coil 3 to which a pulse current is applied is provided in a case 2 made of a magnetic material such as iron. The coil 3 is made of a resin bobbin 4. A guide pipe 6 made of a non-magnetic material is inserted into a through hole formed by winding an electric wire around the bobbin 4.

  A right magnetic pole cylinder 8 made of a magnetic material is connected to the right side of the guide pipe 6 in FIG. 1, and a left magnetic pole cylinder 9 made of a magnetic material is connected to the left side, and a drive space 10 for the plunger 41 described below is formed inside. . A suction joint 14 having a suction passage 13 is screwed into the right opening of the right magnetic pole cylinder 8.

  The right magnetic pole cylinder 8 has a large-diameter hole 16 formed in the axial direction at the center thereof and a valve hole 17 connected to the large-diameter hole 16, and the valve hole 17 communicates with the suction passage 13. The valve hole 17 serves as a valve seat 22 of the suction valve 20 described below.

  The suction valve 20 is a conical valve and includes a valve body 21 and a valve seat 22. The valve body 21 has a bottom surface 21a facing the pump chamber 35, a rod 21b fixed to the top, and a spring receiving member mounted on the rod 21b. 21c is attached. The valve body 21 is seated on the valve seat 22 by a spring 24 interposed between the spring receiver 21 c and the valve seat 22.

  The valve seat 22 is formed in the right magnetic pole cylinder 8 having the valve hole 17 in the center, and has a conical surface (valve hole) such that the pump chamber side is wide and the anti-pump chamber side is narrow so that the valve body 21 is seated. It has become. When the valve element 21 is seated on the valve seat 22, the bottom surface 21 a thereof is flush with the surface 22 a of the valve seat 22 on the pump chamber side.

  The cylinder 26 is a cylindrical member made of polyetheretherketone (PEEK) with little ion elution, and is fitted into a large-diameter hole 16 formed in the right magnetic pole cylinder 8, and its tip is the large-diameter hole 16. The suction valve 20 is inserted into the suction valve 20.

  The piston 27 is made of a nonmagnetic material, and is a cylindrical body having a through hole 28 in the axial direction at the center. The piston 27 is slidably inserted into the cylinder 26 and is driven by a reciprocating movement of a plunger 41 described below. A discharge valve 29 is fixed to the tip which is the right end of the piston 27.

  The discharge valve 29 includes a valve body 30 and a valve seat 31, and the valve body 30 is seated on the valve seat 31 by a spring 33 whose top surface 30b faces the pump chamber 35 and is pressed from the bottom surface 30a. .

  The valve seat 31 is fixed to the tip of the piston 27, has a valve hole 32, and has a conical surface in which the pump chamber side is narrow and the anti-pump chamber side is wide so that the valve body 30 is seated. When the valve body 30 is seated on the valve seat 31, the top surface 30b is flush with the surface 31a of the valve seat 31 on the pump chamber side.

  The pump chamber 35 includes a cylinder 26, a valve body 21 and a valve seat 22 of the suction valve 20 on the distal end side, and a valve body 30 and a valve seat 31 of a discharge valve 29 fixed to the distal end of the piston 27. The bottom surface 21a of the valve body 21 of the valve 20 and the surface 22a of the valve seat 22 on the pump chamber side are flush with each other, and the top surface 30b of the valve body 30 of the discharge valve 29 and the surface 31a of the valve seat 31 on the pump chamber side are also. Further, since the piston 27 becomes flush, the piston 27 can be brought as close as possible to the suction valve 20 side, and the dead space of the pump chamber 35 can be reduced as much as possible.

  A retainer 38 and a cushion 39 are attached to the left end of the cylinder 26 in the drawing to restrict the rightward movement of the plunger 41 described below and prevent noise and vibration. The cushion 39 is made of elastic rubber, which prevents ions from eluting into the fluid being transferred.

  The plunger 41 is made of a magnetic material, and is arranged in the plunger drive space 10 so as to be pressed against the non-cylinder side by a return spring 42 provided between the plunger 26 and the left end thereof. The plunger 41 has a through hole 43 formed therein, and the piston 27 is fitted using the through hole 43. Accordingly, the reciprocating motion of the plunger 41 is transmitted to the piston 27, and the fluid from the pump chamber 35 is caused to flow through the through hole 28 and the through hole 43 of the piston 27 to reach the plunger drive space 10. A closing valve 44 is disposed at the left end (downstream end) of the plunger 41. When the coil 3 is not energized, the closing valve 44 is seated on a valve seat 46 having a valve hole 45 to close the valve hole 45. . The stop valve 44 and the valve seat 46 restrict the movement of the plunger 41 toward the non-piston side, and prevent the fluid from flowing out from the driving space 10 of the plunger or conversely when the pump is stopped.

  When the coil 3 is energized and energized, the plunger 41 is displaced toward the cylinder against the return spring 42, and its right end (upstream end) reaches the cushion 39. That is, the stroke A is displaced. When the coil 3 is de-energized, it is returned by the force of the return spring 42, and the closing valve 44 at the left end is seated on the valve seat 46.

  As described above, the plunger drive space 10 is composed of the guide pipe 6, the left magnetic pole cylinder 9, the right magnetic pole cylinder 8, and the cylinder 26, located on the downstream side of the discharge valve 29, and disposed inside the plunger 41. The formed through-hole 43 is opened, and the discharge fluid is introduced through the through-hole. The plunger drive space 10 communicates with a discharge passage 49 described below via a valve seat 46 having a seat hole 45 formed at the left end of the left magnetic pole cylinder 9.

  The discharge passage 49 is formed in the discharge joint 50, and a backflow prevention valve 51 urged by a spring 52 is provided inside the discharge joint 50 so as to oppose the fluid flow direction. The discharge passage 49 overlaps the valve seat 46 and is provided with a seat hole 57. It is seated on the valve seat 53 that it has. The backflow prevention valve 51 prevents backflow of the plunger to the drive space 10 when the closing valve 44 is opened. The backflow prevention valve 51 allows a fluid flow in the forward direction and opens and closes due to a pressure difference with the plunger drive space 10. That is, since the pressure in the plunger drive space 10 decreases at the beginning of the ascending process from the bottom dead center to the top dead center of the piston 27, the back pressure enters the chamber and applies pressure to the discharge valve 29. In the worst case, the valve 29 cannot be opened, but in this case, the backflow prevention valve 51 is closed to prevent the back pressure from flowing in. In order to prevent the pressure from rising, the opening of the discharge valve 29 acts reliably and the pumping action is performed reliably. 54 and 55 are magnetic plates, and 56 is a mounting plate.

  Also, during the descending process from the top dead center to the bottom dead center of the piston 27, the backflow prevention valve 51 is quickly closed so that the back pressure is not applied to the discharge valve 29. This is also preferable. For this reason, the valve closing speed can be increased by increasing the seat diameter of the valve seats 46 and 53 and increasing the spring constant of the spring 52. The valve opening pressure in the forward direction of the check valve 51 can be adjusted by the seat diameter of the valve seats 46 and 53 and the load of the spring 52, and the pressure loss at this portion is small.

  In the above-described configuration, when a pulse current of, for example, 5 Hz is passed through the coil 3, when the coil 3 is energized when it is turned on, the right magnetic pole cylinder 8, the left magnetic pole cylinder 9, and the plunger 41 are magnetized, and the plunger 41 is applied to the return spring 42. It moves against the right, and its right end abuts against a cushion 39 provided on the cylinder 26, and the rightward movement is stopped. The movement of the plunger 41 is transmitted to the piston 27, the piston 27 is driven to the right, and the pump chamber 35 is reduced from the state shown in FIG. 2 to no dead space. As a result, the pressure in the pump chamber 35 rises, and the discharge valve 29 is opened from the pressure difference, and fluid is discharged from the plunger drive space 10 and the discharge passage 49 to the outside. In this way, the compression ratio increases and the volumetric efficiency is high, so that it is possible to avoid the inconvenience of dissolved air.

  When the pulse current is turned off, the right magnetic pole cylinder 8, the left magnetic pole cylinder 9, and the plunger 41 are demagnetized, and the plunger 41 is moved to the left by the return spring 42, and the stop valve 44 contacts the valve seat 46 and is stopped. The At that time, the volume in the pump chamber 35 increases. As a result, the pressure in the pump chamber 35 decreases, and the suction valve 20 is opened from the pressure difference to suck in fluid. In this embodiment, the volume of the suction passage 13 is reduced as much as possible to prevent the dissolved air from accumulating in the suction passage.

  Then, when the pulse current is turned on again, the plunger 41 and the piston 27 are moved to the right and the pressurizing action is started. Such an action is repeated and a pump action is performed. However, since it is moved left and right with a predetermined stroke A, a constant volume is discharged. Therefore, if it is 5HZ, the discharge amount per second, which is obtained by multiplying the bottom area of the pump chamber 35 by the stroke dimension A and 5 times, is discharged. And the discharge amount can be changed linearly by changing the frequency of the pulse current to the coil 3. In this embodiment, the constant volume can be discharged without change within a range of about ± 3% until the back pressure is about 300 Kpa.

It is sectional drawing which shows the Example of this invention. It is an enlarged view of the principal part same as the above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Constant displacement type electromagnetic pump 2 Case 3 Coil 6 Guide pipe 10 Plunger drive space 13 Suction passage 14 Suction joint 20 Suction valve 21 Valve body 21a Bottom surface 21b Rod 22 Valve seat 22a Pump chamber side surface 26 Cylinder 27 Piston 29 Discharge valve 30 Valve body 30a Bottom surface 30b Top surface 31 Valve seat
31a Pump chamber side surface 35 Pump chamber 39 Cushion 41 Plunger 42 Return spring 44 Stop valve 46 Valve seat 49 Discharge passage 50 Discharge joint 51 Backflow prevention valve

Claims (4)

A cylinder provided between the suction passage and the discharge passage, a piston reciprocating in the cylinder, a discharge valve provided in the piston, and a suction valve provided upstream of the discharge valve; In an electromagnetic pump comprising a plunger for reciprocating the piston and a coil, and performing a pump action by changing a volume of a pump chamber constituted by the suction valve, the discharge valve, and the cylinder,
The discharge valve includes a valve body and a valve seat, the top surface of the valve body is flush with the side of the pump chamber of the valve seat, and the suction valve is upstream of the discharge valve, A constant displacement electromagnetic pump comprising a body and a valve seat, and being flush with a bottom surface of the valve body and a surface of the valve seat on the pump chamber side. A cylinder provided between the suction passage and the discharge passage, a piston reciprocating in the cylinder, a discharge valve provided in the piston, and a suction valve provided upstream of the discharge valve; In an electromagnetic pump comprising a plunger for reciprocating the piston and a coil, and performing a pump action by changing a volume of a pump chamber constituted by the suction valve, the discharge valve, and the cylinder,
The discharge valve includes a valve body and a valve seat so that a top surface of the valve body is flush with a side surface of the pump chamber of the valve seat, and the suction valve is upstream of the discharge valve, A body and a valve seat, so that the bottom surface of the valve body and the surface of the valve seat on the pump chamber side are flush with each other,
The plunger is arranged in a driving space of the plunger formed on the downstream side of the discharge valve, and is configured to be pressed by a return spring when the coil is not excited and to have its downstream end seated on the valve seat. In addition, the upstream end of the coil faces the right magnetic cylinder with a predetermined distance, and when the coil is excited, it is attracted and moved so that the upstream end contacts the right magnetic cylinder and makes a constant stroke. West,
A constant displacement electromagnetic pump, wherein a backflow prevention valve is provided in a discharge passage communicating with a drive space of the plunger in a direction opposite to a fluid flow direction.   The constant displacement electromagnetic pump according to claim 1 or 2, wherein a stop valve is provided at a downstream end of the plunger. 4. The constant displacement electromagnetic pump according to claim 1, wherein the cylinder is made of polyether ether ketone (PEEK).

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