JP5186608B1 - Liquid reciprocating pump - Google Patents

Abstract

To provide a reciprocating pump for liquid that can reduce pulsation and can reduce installation space and cost.
A liquid reciprocating pump includes a drive unit and a pump unit. The pump unit 5 includes a first check valve 53 connected to the suction port, a first bellows 54 connected to the first check valve 53, a second check valve 55 connected to the first bellows 54, and a second check valve 55. A second bellows 56 that is connected to the check valve 55 and communicates with the discharge port and has the same effective sectional area as the first bellows 54 is provided. The drive unit 2 extends the first check valve 53 in the first direction in which the first bellows 54 is compressed and the second direction in which the first check valve 53 extends, and the second check valve 55 extends in the first bellows 54. And a second drive unit that compresses the second bellows 56 and a second drive unit that compresses the first bellows 54 and advances and retracts the second bellows 56 in a second direction.
[Selection] Figure 4

Description

  The present invention relates to a pump that discharges liquid, and more particularly, to a reciprocating pump for liquid with a check valve that discharges liquid while reducing pulsation.

As a positive displacement pump, a plunger pump, a piston pump, a bellows pump, a diaphragm pump, and the like are known.
Since such a reciprocating pump measures the volume of the liquid to be discharged, the discharge accuracy can be improved. On the other hand, since the liquid suction operation and the liquid discharge operation are alternately performed, the liquid is intermittently discharged.

  For example, the bellows pump of Patent Document 1 is provided with a bellows and two check valves disposed at the fluid inlet and the fluid outlet of the bellows, and the bellows is reciprocated (expanded / contracted) to downstream or upstream The check valves are alternately operated, and the liquid suction operation and the discharge operation are repeated. For this reason, although the bellows pump of patent document 1 is suitable for the use which discharges a fixed quantity of liquid intermittently, it cannot discharge a fixed quantity of liquid continuously, ie, without pulsation.

  On the other hand, as in the pump of Patent Document 2, two pumps are arranged in parallel, two channels are provided, and those channels (pumps) are switched to reduce pulsation. Yes.

Japanese Patent No. 3867770 Japanese Patent No. 4585415

  As described above, the bellows pump disclosed in Patent Document 1 alternately performs the liquid suction operation and the liquid discharge operation, and therefore cannot be used for applications in which pulsation occurs and a constant amount of liquid needs to be continuously supplied. There was a problem. This problem is not limited to the bellows pump, and is a problem common to reciprocating pumps such as a plunger pump, a piston pump, and a diaphragm pump that alternately perform a liquid suction operation and a discharge operation.

In addition, since the pump of Patent Document 2 needs to be provided with two systems of pumps, the space is expanded and the liquid is liable to stay in the back, so that the liquid easily changes in quality over time, such as an adhesive. There was a problem that could not be used for discharge.
Furthermore, the pump system cannot be switched instantaneously, and a buffering period is generated at the time of switching. Therefore, it is difficult to make the liquid suction and discharge speed constant, and pulsation is likely to occur.
The problem when these two systems of pumps are provided is a problem common to reciprocating pumps such as a plunger pump, a piston pump, and a diaphragm pump, as well as a bellows pump.

  An object of the present invention is to provide a liquid reciprocating pump that can reduce pulsation, suppress liquid stagnation, and reduce installation space.

The reciprocating pump for liquid according to the present invention is provided between a suction port member in which a liquid suction port is formed, a discharge port member in which a liquid discharge port is formed, and the suction port member and the discharge port member, A pump unit that sucks liquid from the suction port and discharges the liquid from the discharge port; and a drive unit that drives the pump unit, the pump unit including a first check valve communicated with the suction port; A second check valve disposed on the outlet side with respect to the first check valve; a first flow path forming device that forms a first flow path between the first check valve and the second check valve; And a second flow path forming device that forms a second flow path between the check valve and the discharge port member, and the driving unit moves the first check valve toward the discharge port member in a first direction. And move in the second direction approaching the inlet member side. A first drive unit; and a second drive unit configured to move the second check valve in a first direction approaching the discharge port member side and a second direction approaching the suction port member side, the first flow The channel forming device and the second channel forming device have the same effective cross-sectional area of each channel, and expand and contract in the direction of each channel with the movement of the first check valve and the second check valve. The volume of the passage is configured to be changeable, and the first drive unit and the second drive unit have the second check valve opened, and the first check valve is closed at a constant speed in the first direction. The first step of moving and reducing the volume of the flow path from the first flow path to the second flow path to discharge the liquid in the flow path from the discharge port and the first check valve opened The second check valve is closed and moved at the same speed in the first direction to reduce the volume of the second flow path. A second step of alternately discharging the liquid in the second flow path from the discharge port and sucking the liquid into the first flow path from the suction port via the first check valve, The moving speed and the moving amount of the first check valve in the first direction in the first step are the same as the moving speed and the moving amount of the second check valve in the first direction in the second step. Then, the second check valve is moved to a position at the start of constant-velocity movement of the second check valve in the first direction in the second step, and in the second step, the first check valve is moved, In the first step, the first check valve moves to a position at the start of movement at a constant speed in the first direction.
At this time, in the first step, the first driving unit and the second driving unit move the second check valve in the second direction after moving the second check valve in the first direction at a lower speed than the first check valve. Moving, further moving in the first direction at a lower speed than the first check valve, moving to a position at the start of constant-speed movement of the second check valve in the first direction in the second step, In the second step, the first check valve moves in the first direction at a lower speed than the second check valve, then moves in the second direction, and further moves at a lower speed than the second check valve. It is preferable to move in one direction and move to a position at the start of constant speed movement of the first check valve in the first direction in the first step.

According to the present invention, the first check valve, the first flow path forming device, the second check valve, the second flow path forming device, and the discharge port member are connected in series from the suction port member to the first check valve. Liquid can be sucked and discharged by advancing and retracting the first check valve and the second check valve by the drive unit and the second drive unit.
Specifically, in the first step, the first driving unit and the second driving unit open the second check valve and close the first check valve at a constant speed in the first direction. Moving. When the closed first check valve is moved in the first direction at a constant speed (constant speed), the first flow path forming device is reduced at a constant speed. For this reason, the volume of the channel from the first channel formed by the first channel forming device to the second channel formed by the second channel forming device via the second check valve decreases at a constant speed. To do. Accordingly, the liquid in the first flow path and the second flow path is discharged through the discharge port. For this reason, when the first check valve moves at a constant speed, a constant liquid is continuously discharged from the discharge port without pulsation.
In addition, as a 1st and 2nd flow-path formation apparatus, a bellows, a diaphragm, a piston and a cylinder, a plunger, a plunger barrel, etc. can be utilized.

  In the second step, the first drive unit and the second drive unit move at a constant speed in the first direction with the first check valve opened and the second check valve closed. When the second check valve in the closed state is moved at a constant speed (constant speed) in the first direction, the first flow path forming device is extended at a constant speed, and the volume in the first flow path is increased at a constant speed. The second flow path forming device is reduced at a constant speed, and the volume in the second flow path is reduced at a constant speed. For this reason, the liquid in the second flow path is discharged from the discharge port. At this time, the moving speed and moving amount of the second check valve in the first direction are the same as the moving speed and moving amount of the first check valve in the first direction in the first step, and the first flow path and Since the effective cross-sectional area of the second flow path is the same, when the second check valve moves at the same speed, the same amount of liquid as in the first step is continuously discharged from the discharge port without pulsation. Therefore, by repeating the first step and the second step, a constant amount of liquid can be continuously discharged from the discharge port without pulsation.

  Further, since the second check valve moves at a constant speed in the first direction and the volume of the first flow path increases at a constant speed, the first check valve is opened from the suction port to the inside of the first flow path. Liquid is inhaled. Since the liquid suction is performed in conjunction with the movement of the second check valve in the first direction, the same amount of liquid as the liquid discharged from the discharge port is sucked from the suction port. That is, the liquid suction and discharge are realized in the same amount and in the same direction, that is, in the same flow. Therefore, switching between the first step and the second step can be performed smoothly with almost no pulsation.

In addition, since the first check valve and the second check valve are opened and closed by the pressure difference between the upstream side and the downstream side of each check valve, the relative movement of the first check valve and the second check valve in the first direction is performed. Faster speed closes, slower speed opens.
Therefore, in the first step, the second check valve is moved in the second direction, or when moving in the first direction, the second check valve is moved at a speed lower than the moving speed of the first check valve. Can be kept open.
Similarly, in the second step, the first check valve is moved in the second direction, or when moving in the first direction, the first check valve is moved at a speed lower than the movement speed of the second check valve. The valve can be kept open.
For this reason, of the first check valve and the second check valve, the movement speed in the first direction of one check valve that is closed is decreased, and the movement speed in the first direction of the other check valve is increased. If the speed is reversed, the open / close state of the check valve can be smoothly switched at that time without a time lag. Therefore, there is no buffer period when the check valve is switched, and the pulsation is suppressed at this point as well, and a constant amount of liquid can be continuously discharged.

Therefore, according to the reciprocating pump for liquid of the present invention, since a constant amount of liquid can be continuously discharged, pulsation can be reduced. In addition, by connecting two check valves and two flow path forming devices in series and controlling the movement of each check valve, continuous discharge without pulsation can be realized. Installation space and cost can be reduced as compared with the arrangement that eliminates pulsation.
In addition, since the liquid flows through the two flow path forming apparatuses, the liquid staying in the pump portion is small, and the air can be hardly accumulated. Therefore, it is possible to provide a pump that is suitable for discharging liquid that deteriorates over time or liquid that needs to prevent air from entering. In addition, in the pump part, the liquid contact part that comes into contact with the liquid is each flow path forming device and check valve, and since the structure of the liquid contact part is simple, maintenance work such as cleaning of the pump part can be easily performed. Can do.

  In the liquid reciprocating pump according to the present invention, the first check valve includes two check valves, an upstream first check valve and a downstream first check valve, and the second check valve includes an upstream second check valve. The check valve and the downstream second check valve are composed of two check valves, the downstream first check valve is disposed in the first flow path, and the downstream second check valve is the second flow valve. It is preferable to arrange in the road.

Since the first check valve and the second check valve are composed of double check valves each having two check valves on the upstream side (primary side) and the downstream side (secondary side), the opening / closing operation by the check valve is more reliably performed. It can be carried out.
Moreover, since the downstream first check valve and the downstream second check valve are arranged in each flow path formed by each flow path forming device, an increase in size of the pump unit can be prevented. Furthermore, if each check valve is arranged in the flow path, the volume of each flow path can be reduced, and the self-priming ability of the pump unit can be improved.

  In the liquid reciprocating pump of the present invention, the first flow path forming device includes a first bellows coupled to the first check valve and the second check valve, and the second flow path forming device includes Preferably, the second bellows is connected to the second check valve and the discharge port member, and the first bellows and the second bellows have the same effective cross-sectional area of the flow path.

Since the bellows is used as each flow path forming device, when the check valve reciprocates, it can be smoothly expanded and contracted in conjunction with the movement. For this reason, in the pump of the present invention in which the check valve reciprocates, the discharge accuracy can be improved, and the influence of the mechanical accuracy of the drive unit can be reduced.
Moreover, since the liquid flows through the bellows, the liquid can be very little retained. Furthermore, if a bellows is used, the structure of the pump part, in particular, the structure of the liquid contact part can be simplified, and maintenance of the pump part can be easily performed.

  In the reciprocating pump for liquid according to the present invention, the first flow path forming device includes a first piston connected to the first check valve, a second piston connected to the second check valve, and the first piston inserted. The second flow path forming device is connected to the second check valve, to the discharge port member, and the second piston is connected to the discharge port member. And a second cylinder to be inserted, wherein the first piston includes a flow path in the first piston that communicates with the first check valve and the first cylinder, and the second piston includes the second cylinder. A flow path in the second piston communicating with the check valve and the second cylinder is provided, and the effective cross-sectional areas of the first cylinder and the second cylinder are the same.

If a piston and a cylinder are used as each flow path forming device, when the check valve reciprocates, the piston inserted into the cylinder can be moved back and forth smoothly in conjunction with the movement of the check valve. For this reason, in the pump of the present invention in which the check valve reciprocates, the discharge accuracy can be improved, and the influence of the mechanical accuracy of the drive unit can be reduced.
Furthermore, since pistons and cylinders are often cheaper than bellows, the liquid reciprocating pump of the present invention can be realized at low cost.

In the liquid reciprocating pump according to the present invention, it is preferable that the suction port member and the first check valve are connected by a suction port side flow path forming device.
For example, as the inlet side channel forming device, the same devices as the first and second channel forming devices such as bellows, diaphragm, piston and cylinder, plunger and plunger barrel can be used.

If the suction port member and the first check valve are connected by the suction side channel forming device, the movement of the first check valve can be absorbed by the expansion and contraction of the suction port side channel forming device. For this reason, the suction port member can be fixed so as not to move, and the connection between the liquid supply line such as a liquid tank and the suction port member can be easily performed.
Further, if the effective cross-sectional area of the flow path formed by the suction side flow path forming device is the same as that of the first flow path and the second flow path, the liquid suction speed becomes the same as the discharge speed, The flow can be made smooth.

The liquid reciprocating pump according to the present invention includes a container for storing the liquid, and the suction port member is a suction pipe having one end side inserted into the container and the other end side fixed to the first check valve. It is preferable to be configured.
With this configuration, when the suction port member moves together with the first check valve, the liquid suction operation can be continued if the opening on one end side of the suction pipe moves in the liquid of the container. it can. In this case, although it is necessary to provide a container, there exists an advantage which can make an inlet side flow-path formation apparatus unnecessary.

  In the liquid reciprocating pump according to the present invention, the first drive unit includes a first drive arm to which the first check valve is fixed, a first drive shaft to which the first drive arm is fixed, and the first drive arm. A first cam arm fixed to the drive shaft; a first cam follower rotatably held by the first cam arm; a cam having a cam surface against which the first cam follower is in contact; and a rotational drive for rotating the cam. The second drive unit is fixed to the second drive shaft, a second drive shaft to which the second drive arm is fixed, and a second drive shaft to which the second check arm is fixed. A second cam arm, a second cam follower rotatably held by the second cam arm, a cam having a cam surface against which the second cam follower abuts, and a rotational drive source for rotating the cam. For example, each cam follower is preferably 180 ° phase is brought into contact with different positions relative to the cam surface.

According to the present invention, the cam surface of the cam is provided with a cam surface that moves at a constant speed in the first direction in an angle range of 180 °, and both ends of the cam surface are connected in the remaining 180 ° angle range. By providing the cam surface with a uniform acceleration or a cycloid curve, the first step and the second step can be reliably and easily realized.
For example, when a cam surface other than the constant speed cam surface is used as the constant acceleration cam surface, in the first step, the second check valve is moved in the first direction at a constant acceleration, and then in the second direction. In the second step, the first check valve is moved in the first direction at a uniform acceleration, and then moved in the second direction at a uniform acceleration. What is necessary is just to set so that it may move in the 1st direction with equal acceleration.
In addition, the liquid reciprocating pump can be reduced in size by providing only one rotational drive source such as a stepping motor or servo motor, the cam rotated by this rotational drive source, each cam arm, drive shaft, cam follower, etc. -The weight can be reduced, and the cost can be reduced as compared with the case of using a control motor and a ball screw.

It is a side view which shows the reciprocating pump for liquids of 1st Embodiment of this invention. It is a top view which shows the reciprocating pump for liquids of the said embodiment. It is a front view which shows the reciprocating pump for liquids of the said embodiment. It is sectional drawing which shows the reciprocating pump for liquids of the said embodiment. It is sectional drawing along the BB line of FIG. It is sectional drawing along CC line of FIG. It is a figure explaining the detail of a check valve. It is a cam diagram of the cam surface of a cam. It is a figure explaining operation | movement of the reciprocating pump for liquids of the said embodiment. FIG. 10 is a diagram for explaining operation subsequent to FIG. 9. It is sectional drawing which shows the reciprocating pump for liquids of 2nd Embodiment of this invention. It is sectional drawing which shows the reciprocating pump for liquids of 3rd Embodiment of this invention. It is sectional drawing which shows the reciprocating pump for liquids of 4th Embodiment of this invention.

[First Embodiment]
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a first embodiment of the invention will be described with reference to the drawings.
As shown in FIG. 1, the liquid reciprocating pump 1 includes a drive unit 2 and a pump unit 5 that incorporate a drive mechanism.

[Configuration of drive unit]
As shown in FIGS. 2 and 3, the drive unit 2 includes a box-shaped housing 3. In the housing 3, as shown in FIGS. 4 to 6, a motor 15, a cam 20, and two Drive shafts 31, 32 and the like are incorporated. 4 is a cross-sectional view taken along the line AA indicated by the alternate long and short dash line in FIG. 5 and 6 are cross-sectional views taken along the BB line and CC line indicated by the alternate long and short dash line in FIG.

[Case]
The housing 3 includes a frame 10, a rear cover 11, and left and right side covers 12. As shown in FIG. 4, the frame 10 is configured by bending a metal plate into a substantially U shape, and includes a bottom surface portion 101, a front surface portion 102, and a top surface portion 103.
Both side surfaces of the side cover 12 are also bent, and the front part 102 and the rear cover 11 are screwed to the bent both end surfaces, so that the frame 10, the rear cover 11, and the side cover 12 are configured. The body 3 is assembled in a box shape. Further, a handle 13 is fixed to the upper surface portion 103 as shown in FIG.

[motor]
Four motor support rods 16 that support the motor 15 are erected on the bottom surface portion 101. The motor 15 is supported by abutting and fixing the upper surface of the motor support rod 16 to the lower surface of the flange of the motor 15.
The rear cover 11 is provided with a connector 17 for connecting a signal line for controlling the motor 15 to the controller, and a power line (not shown) for supplying power to the motor 15.

  As the motor 15, a control motor such as a stepping motor or a servo motor is used. A gear coupling 18 is fixed to the output shaft 151 of the motor 15, and external teeth of the gear coupling 18 mesh with internal teeth formed on the central shaft of the cam 20. For this reason, the output shaft of the motor 15 rotates integrally with the cam 20 via the gear coupling 18.

[cam]
The cam 20 is an end surface cam (solid cam) having a cam surface 21 formed on the end surface, and the cam surface 21 has a cam shape according to a predetermined cam diagram. That is, the cam 20 has a through hole in which the inner teeth are formed in the central shaft portion, and a cam surface 21 is formed in a ring shape around the through hole. The shape of the cam surface 21 will be described later.

  The cam 20 is rotatably supported by a ball bearing 22. The ball bearing 22 is supported by four bearing support rods 23 fixed to the upper surface portion 103.

[Drive shaft]
In the housing 3, a first drive shaft 31 and a second drive shaft 32 configured by cylindrical pipes are arranged so as to be movable in the vertical direction.
That is, a cylindrical lower guide 105 is fixed to the bottom surface portion 101. The lower guide 105 is guided such that the lower end portions of the drive shafts 31 and 32 are slidable in the vertical direction.
Further, a hole is formed in the upper surface portion 103, and the upper end portions of the drive shafts 31 and 32 protrude above the upper surface portion 103 through the holes. An upper guide 106 is screwed to the upper surface portion 103 to guide the upper end portions of the drive shafts 31 and 32 so as to be slidable in the vertical direction.

[Cam arm]
A first cam arm 33 and a second cam arm 34 are fixed to the drive shafts 31 and 32, respectively. As shown in FIG. 5, the cam arms 33 and 34 include wide body portions 331 and 341 and arm portions 332 and 342 narrower than the body portions 331 and 341.
The main body portions 331 and 341 are formed with through holes 333 and 343, split grooves 334 and 344 communicating with the through holes 333 and 343, and holes orthogonal to the split grooves 334 and 344, and bolts 335 are formed in the holes. Is screwed.
The camshafts 33 and 34 are fixed to the drive shafts 31 and 32 by inserting the drive shafts 31 and 32 into the through holes 333 and 343 and cleaving the split grooves 334 and 344 with the bolts 335.

A roller-shaped first cam follower 336 and a second cam follower 346 are rotatably supported on the arm portions 332 and 342.
Further, as shown in FIG. 4, a pair of cylindrical spring seats 337 are inserted through the drive shafts 31 and 32. Between the pair of spring seats 337, a return spring 338 made of a coil spring inserted through the drive shafts 31 and 32 is disposed.
The spring seat 337 is in contact with the lower surface of the upper surface portion 103 and the upper surfaces of the cam arms 33 and 34. Therefore, the cam arms 33 and 34 are biased downward by the return spring 338.
Therefore, the cam followers 336 and 346 are always in contact with the cam surface 21 of the cam 20, and the cam arms 33 and 34 move up and down as the cam followers 336 and 346 follow the cam surface 21. The drive shafts 31 and 32 move up and down in conjunction with the up and down movement of the cam arms 33 and 34.

[Drive arm]
A first drive arm 36 and a second drive arm 37 are attached to the drive shafts 31 and 32 so as to be spaced apart from each other by a predetermined distance. For this reason, the first drive arm 36, the second drive arm 37, the first cam arm 33, and the second cam arm 34 are attached to the drive shafts 31 and 32 in this order from the lower side.

[First drive arm]
As shown in FIG. 6, the first drive arm 36 includes a main body 361 and an arm 362 having a smaller thickness than the main body 361.
The main body 361 is formed with a planar circular through hole 363, a split groove 364 communicating with the through hole 363, and a planar rectangular concave groove 365 opened on the side surface. Further, a through hole 366 that penetrates the split groove 364 is formed on the side surface of the main body 361.

  The first drive shaft 31 is inserted into the through hole 363, and a bolt 367 is inserted into the through hole 366 and screwed into a screw formed in the through hole 366 to tighten the split groove 364, thereby The first drive arm 36 is fixed to the first drive shaft 31 and moves up and down in conjunction with the vertical movement of the first drive shaft 31.

On the other hand, an anti-rotation block 368 is fitted in the concave groove 365. That is, the detent block 368 has an intermediate width dimension (a dimension perpendicular to the opening direction of the groove 365) that is the same as the width dimension of the groove 365, and the width dimension of the flange portions at the upper and lower ends is a groove. It is larger than 365. Therefore, the rotation prevention block 368 is fitted to the first drive arm 36 so as not to rotate.
The anti-rotation block 368 is formed with a through hole 3681 penetrating in the vertical direction. The second drive shaft 32 is inserted through the through hole 3681.
Therefore, when the first drive arm 36 moves up and down together with the first drive shaft 31, the detent block 368 can slide up and down with respect to the second drive shaft 32.

The arm part 362 is disposed so as to protrude from the pump part 5 described later, and a semicircular groove part 3621 is formed on the end face thereof.
A driving arm set block 369 is fixed to the end surface of the arm portion 362 with two bolts 370. A semicircular groove 3691 is formed on the end surface of the drive arm set block 369 facing the arm 362. Accordingly, a circular groove constituted by the groove part 3621 and the groove part 3691 is formed between the arm part 362 and the drive arm set block 369.

[Second drive arm]
Similar to the first drive arm 36, the second drive arm 37 includes a main body portion 371 and an arm portion 372 having a smaller thickness than the main body portion 371.
The main body 371 is formed with a planar circular through hole (not shown) like the main body 361, a split groove (not shown) communicating with the through hole, and a flat rectangular concave groove 375 opened on the side surface. ing. Further, a through hole (not shown) that penetrates the split groove is formed on the side surface of the main body 371. The concave groove 375 is fitted with a detent block 378 having a through hole 3781.

Here, the main body portion 361 of the first drive arm 36 and the main body portion 371 of the second drive arm 37 are disposed such that the planar positions of the through hole 363 and the concave grooves 365 and 375 are opposite. That is, the first drive arm 36 and the second drive arm 37 are composed of the same parts, but are arranged with the front and back reversed at the time of assembly.
For this reason, in the second drive arm 37, the first drive shaft 31 is inserted into the through hole 3781 of the detent block 378, and the second drive shaft 32 is inserted into and fixed to the through hole communicating with the dividing groove. .
Accordingly, the second drive arm 37 moves up and down in conjunction with the vertical movement of the second drive shaft 32, and the first drive arm 36 slides relative to the second drive shaft 32.

The arm portion 372 of the second drive arm 37 is also disposed so as to protrude from the pump portion 5, and a semicircular groove portion is formed on the end surface thereof.
A drive arm set block 379 is fixed to the end face of the arm portion 372 with two bolts 380. A semicircular groove is formed on the end surface of the drive arm set block 379 facing the arm 372. Accordingly, a circular groove is also formed between the arm portion 372 and the drive arm set block 379.

[Moving the drive arm]
Accordingly, the first drive arm 36 moves up and down together with the first cam arm 33 and the first drive shaft 31, and the second drive arm 37 moves up and down together with the second cam arm 34 and the second drive shaft 32.
Further, the first cam follower 336 of the first cam arm 33 and the second cam follower 346 of the second cam arm 34 are arranged at point-symmetric positions with the rotation axis of the cam 20 in between. For this reason, the cam followers 336 and 346 are in contact with the cam surface 21 at a position different by 180 degrees, and the movement operation is the same with a phase shift of 180 degrees.

In the drive unit 2 described above, the first drive shaft 31, the first cam arm 33, the first cam follower 336, the cam 20 having the cam surface 21, and the motor 15 that rotates the cam 20 constitute a first drive unit.
The second drive shaft 32, the second cam arm 34, the second cam follower 346, the cam 20 having the cam surface 21, and the motor 15 that rotates the cam 20 constitute a second drive unit.

[Configuration of pump section]
Next, the configuration of the pump unit 5 will be described.
The pump unit 5 is provided outside the front surface portion 102 of the housing 3 and is sequentially provided with a suction port member 51, a suction bellows 52, a first check valve 53, and a first bellows 54 provided from the bottom to the top. The second check valve 55, the second bellows 56, and the discharge port member 57 are mainly provided.

[Suction port member]
The suction port member 51 includes a suction port side port case 510, and a suction port joint 511 and a port block 513 communicating with the suction port joint 511 are incorporated in the suction port side port case 510.
The inlet joint 511 has a through hole 512, and a female screw is formed in the through hole 512. The liquid supply tube is connected to the inlet joint 511 by screwing a male screw formed on a joint (not shown) of the liquid supply tube to the female screw.
The port block 513 is formed by bending a flow path 514 communicating with the through hole 512 by 90 degrees.

As shown in FIGS. 1 to 3, the suction port side port case 510 is attached to the front surface portion 102 of the housing 3 by two bolts 515.
A flange nut 516 having a flat rectangular plate shape and having an internal thread formed therein is fixed to the upper surface of the suction port side port case 510 by screws (not shown) that are screwed into the suction port side port case 510. Yes.

[Discharge port member]
The discharge port side port case 570, the discharge port joint 571, and the port block 573 constituting the discharge port member 57 are composed of the same components as the suction port side port case 510, the suction port joint 511, and the port block 513.
For this reason, the discharge port side port case 570 of the discharge port member 57 incorporates a discharge port joint 571 and a port block 573 communicating with the discharge port joint 571, similarly to the suction port side port case 510.
The discharge port joint 571 is formed with a through hole 572, and a female screw is formed in the through hole 572. The liquid discharge tube is connected to the discharge port joint 571 by screwing a male screw formed on a joint (not shown) of the liquid discharge tube to the female screw.
The port block 573 is formed by bending a flow path 574 communicating with the through hole 572 by 90 degrees.

As shown in FIGS. 1 to 3, the discharge port side port case 570 is attached to the front surface portion 102 of the housing 3 by two bolts 575.
Further, a flange nut 576 having a flat rectangular plate shape and having a female screw formed therein is fixed to the lower surface of the discharge port side port case 570 by a screw (not shown) screwed into the discharge port side port case 570. Yes.

Accordingly, the suction port member 51 and the discharge port member 57 are fixed to the housing 3 and do not move up and down.
Further, a connecting plate 58 is fixed to the suction port side port case 510 and the discharge port side port case 570, and a front cover 59 that covers the suction port bellows 52 to the second bellows 56 is attached thereto. Yes.

[First check valve]
The first check valve 53 is sandwiched between an arm portion 362 of the first drive arm 36 and a drive arm set block 369 fixed to the arm portion 362.
As shown in FIG. 7, the first check valve 53 includes a check valve case 531, a valve seat 532, a ball guide block 533, a ball 534, a ring member 535, and cap nuts 536 and 537. . As will be described later, since the first check valve 53 and the second check valve 55 are the same component, the number of the second check valve 55 is also described in FIG.

The check valve case 531 is formed of a cylindrical pipe, and the thickness of the upper and lower end portions is larger than the thickness of the intermediate portion. A groove is formed on the outer periphery of the thick portion at the upper and lower ends, and a ring member 535 such as a stop ring is fitted in the groove.
Therefore, after inserting the cap nuts 536 and 537 into the outer periphery of the lower end side and the upper end side of the check valve case 531, the ring nut 535 is fitted into the groove of the check valve case 531 so that the cap nuts 536 and 537 are inserted. It is prevented from coming off.

  The valve seat 532 is formed with a communication hole 5321 that communicates with the inlet bellows 52. The upper and lower openings of the communication hole 5321 are tapered surfaces 5322. As shown in FIG. 7A, when the ball 534 contacts the tapered surface 5322, the communication hole 5321 is closed, that is, a first check is performed. The valve 53 can be closed.

  The ball guide block 533 is formed with a guide groove 5331 for guiding the ball 534 and three communication grooves 5332 formed on the outer peripheral side of the guide groove 5331. Accordingly, as shown in FIG. 7B, when the ball 534 moves upward along the guide groove 5331 and moves away from the tapered surface 5322, the communication groove 5332 is connected to the inlet bellows 52 via the communication hole 5321. It communicates with the internal space. That is, the first check valve 53 is opened.

The first check valve 53 is fixed to the first drive arm 36 by the drive arm set block 369. That is, as described above, the circular groove formed between the drive arm set block 369 and the arm portion 362 is brought into contact with the thin portion of the check valve case 531 so as to sandwich the check valve case 531.
Accordingly, when the first drive arm 36 moves up and down, the first check valve 53 also moves up and down together.

[Second check valve]
The second check valve 55 is sandwiched between an arm portion 372 of the second drive arm 37 and a drive arm set block 379 fixed to the arm portion 372.
As shown in FIG. 4, the second check valve 55 includes a check valve case 551, a valve seat 552, a ball guide block 553, a ball 554, a ring member 555, and cap nuts 556 and 557. Since the structure of the second check valve 55 is the same as that of the first check valve 53, description thereof is omitted. For example, the valve seat 552 has a communication hole 5521 and a tapered surface 5522, and the ball guide block 553 has a guide groove 5531 and a communication groove 5532.

The first check valve 53 and the second check valve 55 are gravity check valves that are closed when the balls 534 and 554 move downward. The first check valve 53 and the second check valve 55 are set so that liquid flows from the suction port member 51 to the discharge port member 57.
Accordingly, the pressure applied to the balls 534 and 554 by the liquid below the first check valve 53 and the second check valve 55, that is, the suction side, and the pressure applied to the balls 534 and 554 by the liquid on the upper side, that is, the discharge side, When it is larger than the total value of the applied gravity, the pressure difference causes the balls 534 and 554 to move upward to open the check valve.
On the other hand, in other cases, the balls 534 and 554 move downward to come into contact with the valve seat 532 and the check valve is closed.

[Bellows for inlet]
The suction port bellows 52 is disposed between the port block 513 and the first check valve 53. The suction port bellows 52 constitutes the suction port side flow path forming apparatus of the present invention.
The suction port bellows 52 includes a flange portion 521 on the lower end side and a flange portion 522 on the upper end side. Male threads are formed on the outer circumferences of the flange portions 521 and 522.

  The flange portion 521 on the lower end side is screwed into the flange nut 516, and the lower end surface of the flange portion 521 contacts the upper surface of the port block 513. As a result, there is no gap between the flange portion 521 and the port block 513, and the internal space of the inlet bellows 52 is communicated with the flow path 514.

  The upper flange portion 522 is screwed into the cap nut 523, and the upper surface of the flange portion 522 contacts the lower surface of the valve seat 532. As a result, there is no gap between the flange portion 522 and the valve seat 532, and the internal space of the inlet bellows 52 is communicated with the communication hole 5321 of the valve seat 532.

[First bellows]
The first bellows 54 is disposed between the first check valve 53 and the second check valve 55. This first bellows 54 constitutes the first flow path forming device of the present invention. The first bellows 54 includes flange portions 541 and 542 at the lower end portion and the upper end portion, similarly to the suction port bellows 52.
The expansion / contraction amount of the first bellows 54 is set to be twice the expansion / contraction amount of the inlet bellows 52. Specifically, the length of the bellows portion of the first bellows 54 is set to be twice that of the inlet bellows 52.

A cap nut 536 is engaged with the ring member 535 on the upper side of the first check valve 53. The first bellows 54 is attached by screwing a male screw formed on the outer periphery of the flange portion 541 into the cap nut 536.
A male screw is also formed on the outer periphery of the flange portion 542 on the upper end side of the first bellows 54, and a cap nut 556 is screwed together.
Accordingly, the lower end surface of the first bellows 54 is in close contact with the upper surface of the ball guide block 533 of the first check valve 53 without any gap, and the internal space of the first bellows 54 communicates with the communication groove 5332.
Further, the upper end surface of the first bellows 54 is in close contact with the lower surface of the valve seat 552 of the second check valve 55 without a gap, and the internal space of the first bellows 54 communicates with the communication hole 5521 of the valve seat 552.

[Second bellows]
The second bellows 56 is disposed between the second check valve 55 and the discharge port side port case 570. This second bellows 56 constitutes the second flow path forming device of the present invention. The second bellows 56 is provided with flange portions 561 and 562 at the lower end portion and the upper end portion similarly to the bellows 52 for the inlet, and male screws are formed on the outer circumferences of the flange portions 561 and 562.
The expansion / contraction amount of the second bellows 56 is set to be the same as the expansion / contraction amount of the inlet bellows 52, that is, ½ of the first bellows 54. Specifically, the length of the bellows portion of the second bellows 56 is set to be the same as that of the suction port bellows 52.

The second bellows 56 is connected to the second check valve 55 by screwing a flange portion 561 on the lower end side into the cap nut 557.
The second bellows 56 is coupled to the discharge port member 57 by screwing the flange portion 562 on the upper end side into a flange nut 576 fixed to the discharge port member 57.
Accordingly, the lower end surface of the second bellows 56 is in close contact with the upper surface of the ball guide block 553 of the second check valve 55 without a gap, and the internal space of the second bellows 56 communicates with the communication groove 5532.
Further, the upper end surface of the second bellows 56 is in close contact with the lower surface of the port block 573 without any gap, and the internal space of the second bellows 56 communicates with the flow path 574 of the port block 573.

  In the present embodiment, at least the first bellows 54 and the second bellows 56 must have the same cross-sectional area (effective area). Thereby, the amount of change in the volume from the closed check valve (the first check valve 53 or the second check valve 55) to the discharge port member 57 can be proportional to the amount of movement of the closed check valve, The liquid discharge amount can also be made proportional. Further, the cross-sectional area of the suction bellows 52 is preferably set to be the same as that of the first bellows 54 and the second bellows 56. Thereby, the suction speed of the liquid can be made the same as the discharge speed, and the flow of the liquid can be made smooth.

[Cam surface of cam]
As described above, the cam 20 is constituted by an end face cam (solid cam) having a cam face 21 formed on the end face, and the cam face 21 has a cam shape corresponding to the cam diagram shown in FIG. That is, the cam 20 has a through hole formed in the central shaft portion, and a cam surface 21 formed in a ring shape around the through hole.
The y-axis of the cam diagram shown in FIG. 8 indicates the displacement of the cam 20 in the axial direction, that is, the displacement of the drive shafts 31 and 32 in the axial direction. On the other hand, the x-axis represents the rotation angle of the cam 20, that is, the relative rotation angle of the cam surface 21 with respect to the cam followers 336 and 346. In the cam diagram, the movement locus of the center position (rotation axis) of the cam followers 336 and 346 is also described.

Since the two cam followers 336 and 346 are disposed at positions different from the cam surface 21 by 180 degrees, the phase of the cam surface 21 is also shifted by 180 degrees.
In the cam diagrams shown in FIGS. 8A and 8B , when X = 0 °, Y = 0 (intermediate point between the top dead center and the bottom dead center), and the upper part is represented by plus and the lower part is represented by minus.
For the cam follower 336 shown in FIG. 8 (A), the cam surface 21 of the rotational angle of the cam 20 from 0 ° to 90 °, for example, is represented by y = 4 (x-67.5) 2 /10125-1.8 Is a quadratic curve. For this reason, the cam follower 336 moves with a uniform acceleration motion downward until 67.5 ° and moves with a uniform acceleration motion upward from 67.5 ° to 90 °.
The cam surface 21 from 90 ° to 270 ° is, for example, a straight line represented by y = 1.6 (x−180) / 90. For this reason, the cam follower 336 moves at a constant speed upward.
Furthermore, the cam surface 21 from 270 ° to 360 °, for example, a quadratic curve expressed by y = -4 (x-292.5) 2 /10125+1.8. For this reason, the cam follower 336 moves with a constant acceleration motion upward until 292.5 °, and moves downward with a constant acceleration motion from 292.5 ° to 360 °.

With respect to the cam follower 346 shown in FIG. 8B, the cam surface 21 in which the rotation angle of the cam 20 is 0 ° to 90 ° is, for example, a straight line represented by y = 1.6x / 90. For this reason, the cam follower 346 moves at a constant speed upward.
The cam surface 21 to 180 ° from 90 °, for example, a quadratic curve expressed by y = -4 (x-112.5) 2 /10125+1.8. Therefore, the cam follower 346 moves upward with a uniform acceleration motion up to 112.5 °, and moves downward with a uniform acceleration motion from 112.5 ° to 180 °.
Furthermore, the cam surface 21 from 180 ° to 270 °, for example, a quadratic curve expressed by y = 4 (x-247.5) 2 /10125-1.8. For this reason, the cam follower 346 moves downward with a constant acceleration motion up to 247.5 °, and moves upward with a constant acceleration motion from 247.5 ° to 270 °.
Further, the cam surface 21 from 270 ° to 360 ° is, for example, a straight line represented by y = 1.6 (x−360) / 90. For this reason, the cam follower 346 moves at a constant speed upward.

When the cam followers 336 and 346 move up and down, the first check valve 53 and the second check are passed through the cam arms 33 and 34, the drive shafts 31 and 32, the drive arms 36 and 37, and the drive arm set blocks 369 and 379, respectively. The valve 55 moves up and down.
Accordingly, the first check valve 53 rises by an upward uniform acceleration motion while rotating 22.5 ° from the bottom dead center, and further moves at a constant velocity while rotating 180 ° at the upward speed at that time. Next, the first check valve 53 reaches the top dead center by an upward uniform acceleration motion while rotating 22.5 °. When the first check valve 53 moves 67.5 ° from the top dead center at the same acceleration, the first check valve 53 reaches the maximum downward speed (three times the constant speed movement). Further, the first check valve 53 moves 67.5 ° with the same downward acceleration and returns to the bottom dead center. The second check valve 55 moves 180 degrees out of phase with the first check valve 53.
Since the cam surface 21 is represented by the above cam diagram, it is possible to eliminate the speed difference when switching between the constant acceleration motion and the constant velocity motion, and the constant acceleration motion and the constant velocity motion of each check valve 53, 55 can be eliminated. Switching can be performed smoothly.

  Here, the first check valve 53 and the second check valve 55 are gravity-type check valves, and the one having a relatively high upward speed is closed and the other is open. That is, as shown in the cam diagram, the check valve that is moving at a constant speed is closed. As the closed check valve moves upward, the liquid is discharged from the discharge port member 57. Therefore, when the movement amount of the closed check valve that performs the action of discharging the liquid is synthesized, a straight line having a constant inclination (constant velocity motion) is obtained as shown in FIG. The discharge amount of the liquid is proportional to the movement amount of the check valve, that is, the movement of the drive shafts 31 and 32. In this embodiment, as shown in FIG. 8C, the check valve in the closed state moves from 0 ° to 360 ° at a constant speed by the operation of the two check valves. Proportional liquid velocity, that is, discharge amount is obtained.

Next, the operation of the present embodiment will be described with reference to FIGS.
[Discharge preparation]
When the pump unit 5 is driven by the drive unit 2 because the dead space of the first flow path or the second flow path of the liquid reciprocating pump 1 exceeds a range of the self-priming capacity of the pump unit 5 In order to prepare for liquid discharge, the liquid is pumped from the suction port member 51.
In this case, the check valves 53 and 55 are released by pressure-feeding liquid from the suction port member 51 so that the balls 534 and 554 move upward. Therefore, each liquid flows through the flow path of the pump unit 5, that is, the suction port member 51, the suction port bellows 52, the first check valve 53, the first bellows 54, the second check valve 55, the second bellows 56, and the discharge port. Sequentially supplied to the member 57. The discharge preparation is completed by filling the flow path of the pump unit 5 with the liquid.
In addition, if the dead space of a 1st flow path or a 2nd flow path is small, and is in the range of the self-priming capability of the pump part 5, it is not necessary to pump the said liquid.

[Discharge operation]
When the cam 20 is rotated by the motor 15, the liquid is continuously discharged without pulsation at a discharge amount proportional to the rotation angle of the cam 20, as described below.
That is, when the rotation angle of the cam 20 is from 0 ° to 67.5 °, the first check valve 53 moves upward at a constant speed, and the second check valve 55 moves downward at a constant acceleration. For this reason, the first check valve 53 having a fast upward movement speed is closed, and the second check valve 55 is opened. Therefore, the liquid is discharged from the discharge port member 57 in proportion to the upward movement amount of the first check valve 53, that is, the rotation angle of the cam 20.
Further, when the first check valve 53 moves upward, the suction port bellows 52 extends and the inside becomes negative pressure, so that liquid is sucked into the suction port bellows 52 from the suction port member 51.

When the rotation angle of the cam 20 is 67.5 ° to 90 °, the first check valve 53 continues to move upward at a constant speed, and the second check valve 55 moves upward at a constant acceleration. In this section, since the moving speed of the first check valve 53 is faster than that of the second check valve 55, the first check valve 53 is closed and the second check valve 55 is kept open.
For this reason, from the discharge port member 57, the liquid discharge proportional to the upward movement amount of the first check valve 53, that is, the rotation angle of the cam 20, continues, and the suction port member 51 enters the suction port bellows 52. Liquid inhalation will continue.

When the rotation angle of the cam 20 is 90 ° to 112.5 °, the second check valve 55 moves upward at a constant speed, and the first check valve 53 moves upward at a constant acceleration. In this section, since the moving speed of the second check valve 55 is faster than that of the first check valve 53, the second check valve 55 is closed and the first check valve 53 is opened.
Therefore, the liquid is discharged from the discharge port member 57 in proportion to the upward movement amount of the second check valve 55, that is, the rotation angle of the cam 20.
Further, since the second check valve 55 moves upward, the first bellows 54 extends and the inside becomes negative pressure, so that the inside of the first bellows 54 passes through the first check valve 53 opened from the inlet bellows 52. Liquid is inhaled. Further, the liquid suction from the suction port member 51 into the suction port bellows 52 is continued.

When the rotation angle of the cam 20 is 112.5 ° to 247.5 °, the second check valve 55 continues to move upward at a constant speed, and the first check valve 53 moves downward at a constant acceleration. For this reason, the 1st check valve 53 opens and the 2nd check valve 55 maintains a closed state.
For this reason, liquid discharge that is proportional to the upward movement amount of the second check valve 55, that is, the rotation angle of the cam 20, continues from the discharge port member 57, and the suction port bellows 52, the first Liquid inhalation into the bellows 54 is also continued.

When the rotation angle of the cam 20 is 247.5 ° to 270 °, the second check valve 55 continues to move upward at a constant speed, and the first check valve 53 moves upward at a constant acceleration. In this section, since the moving speed of the second check valve 55 is faster than that of the first check valve 53, the first check valve 53 is opened and the second check valve 55 is kept closed.
For this reason, the discharge port 57 continues to discharge the liquid in proportion to the upward movement amount of the second check valve 55, that is, the rotation angle of the cam 20, and the suction port member 51 enters the suction port bellows 52. Liquid inhalation will continue.

When the rotation angle of the cam 20 is from 270 ° to 292.5 °, the first check valve 53 moves upward at a constant speed, and the second check valve 55 moves upward at a constant acceleration. For this reason, the first check valve 53 having a fast upward movement speed is closed, and the second check valve 55 is opened. Therefore, the liquid is discharged from the discharge port member 57 in proportion to the upward movement amount of the first check valve 53, that is, the rotation angle of the cam 20.
Further, the first check valve 53 moves upward, so that the suction bellows 52 extends and the inside becomes negative pressure, so that liquid suction from the suction port member 51 into the suction bellows 52 is continued. .

When the rotation angle of the cam 20 is from 292.5 ° to 360 °, the first check valve 53 continues to move at a constant speed upward, and the second check valve 55 moves downward at a constant acceleration. For this reason, the first check valve 53 is closed and the second check valve 55 is kept open.
For this reason, from the discharge port member 57, the liquid discharge proportional to the upward movement amount of the first check valve 53, that is, the rotation angle of the cam 20, continues, and the suction port member 51 enters the suction port bellows 52. Liquid inhalation will continue.

By repeating the above operation, the suction of the liquid from the suction port member 51 and the discharge of the liquid from the discharge port member 57 are continuously performed, and the continuous discharge of the liquid without pulsation can be realized.
In the liquid reciprocating pump 1, since the discharge amount for each rotation angle of the cam 20 is constant, the liquid discharge amount can be controlled in proportion to the rotation angle of the cam 20. Therefore, the discharge amount per unit time can also be controlled by adjusting the rotation speed of the cam 20.

According to this embodiment, there are the following effects.
(1) The first check valve 53, the first bellows 54, the second check valve 55, and the second bellows 56 are provided, the effective cross-sectional areas of the first bellows 54 and the second bellows 56 are the same, and the first check One of the valve 53 and the second check valve 55 is closed, the other is opened, and the amount of upward movement of the closed check valves 53, 55 is constant at a constant speed.
For this reason, when the first check valve 53 is opened and the second check valve 55 is closed, the liquid inside the second bellows 56 is discharged from the discharge port member 57 by the upward movement of the second check valve 55. In addition, the same amount of liquid as the discharge amount can be sucked into the first bellows 54 via the suction port member 51, the suction port bellows 52, and the first check valve 53.
Similarly, when the first check valve 53 is closed and the second check valve 55 is open, the first check valve 53 communicates via the second check valve 55 by the upward movement of the first check valve 53 and The liquid in the second bellows 56 can be discharged from the discharge port member 57, and the same amount of liquid can be sucked into the suction port bellows 52 from the suction port member 51.
Therefore, the flow on the suction side can be the same as that on the discharge side, and a constant amount of liquid without pulsation can be continuously discharged from the discharge port member 57 in proportion to the amount of movement of the closed check valves 53 and 55. it can.

(2) A first check valve compared to a conventional liquid reciprocating pump that enables two pumps to be arranged in parallel and alternately switching the liquid discharge for each one, thereby enabling discharge without pulsation. 53, the first bellows 54, the second check valve 55, and the second bellows 56 may be connected in series, so that the liquid reciprocating pump 1 can be made compact. Therefore, it is particularly suitable as a pump that continuously discharges a very small amount of liquid.

(3) The liquid flows in one direction from the suction port member 51 to the suction port bellows 52, the first check valve 53, the first bellows 54, the second check valve 55, the second bellows 56, and the discharge port member 57. In particular, since the liquid flows through the bellows 52, 54, and 56, the amount of liquid that stays in the liquid supply path is small, and air does not easily accumulate.
In addition, the suction port member 51 is disposed on the lower end side of the liquid reciprocating pump 1 and the discharge port member 57 is disposed on the upper end side, so that the liquid flows through the bellows 52, 54, and 56 from the bottom to the top. Therefore, even if bubbles or the like are mixed, it can be easily discharged from the discharge port member 57.
For this reason, since it is possible to prevent air from being mixed into the discharge liquid and to suppress the liquid staying in the flow path, the liquid reciprocating pump 1 can be used for discharging various types of liquid.

(4) Since the suction port member 51 and the first check valve 53 are connected by the suction port bellows 52, even if the first check valve 53 moves up and down, the displacement of the suction port bellows 52 is reduced. Can be absorbed by stretching. For this reason, the inlet member 51 can be fixed. Therefore, it can be used in the same manner as a general pump having a fixed suction port.
Similarly, the discharge port member 57 and the second check valve 55 are connected by the second bellows 56, and the displacement of the second check valve 55 can be absorbed by the expansion and contraction of the second bellows 56. Can be fixed. Therefore, it can be used in the same manner as a general pump having a fixed discharge port.

(5) The liquid discharge amount is set by the upward movement amount of the closed check valves 53 and 55, and the upward movement of the closed check valves 53 and 55 is proportional to the rotation angle of the cam 20. Due to the constant velocity motion, a liquid velocity proportional to the rotation of the cam 20 can be obtained. For this reason, the discharge amount per fixed time can be easily adjusted by the rotational speed of the cam 20.

(6) Since the check valves 53 and 55 are moved in conjunction with the cam arms 33 and 34 and the drive shafts 31 and 32 that are moved up and down by the cam 20, the cam followers 336 and 346 are arranged on the rotation axis of the cam 20. The operation of the check valves 53 and 55 can be realized reliably and easily with a phase difference of 180 ° only by placing them at 180 ° positions. Therefore, the liquid reciprocating pump 1 with high operation reliability can be realized at low cost.

(7) Since the liquid flows from the lower part to the upper part of the pump unit 5, gravity check valves can be used as the check valves 53 and 55. For this reason, the reliability of operation | movement of a check valve can also be improved, and cost can also be reduced compared with the check valve with a spring.

(8) By using the bellows 52, 54, and 56, the liquid portion structure in contact with the liquid can be simplified, and maintenance of the bellows unit can be facilitated. For this reason, the liquid reciprocating pump 1 can be used for discharging various types of liquids.

[Second Embodiment]
As shown in FIG. 11, the liquid reciprocating pump 1 </ b> A of the second embodiment includes a tank 70 in which liquid is stored, and a liquid suction pipe 71 having one end inserted into the tank 70 is used as an inlet member. The liquid suction pipe 71 is fixed to the first check valve 53. Since other configurations are the same, description thereof is omitted.
In this liquid reciprocating pump 1A, even if the liquid suction pipe 71 moves up and down integrally with the first check valve 53, if the lower end is located in the liquid in the tank 70, the liquid is sucked and discharged. can do.

Further, as shown in FIG. 11, the volume of the ball guide block 533A of the first check valve 53 is increased. The length of the ball guide block 533A is set so that the ball guide block 533A and the second check valve 55 do not come into contact with each other by the movement of the first check valve 53 and the second check valve 55 by the cam 20. Good.
In this case, the dead space of the first bellows 54 disposed between the check valves 53 and 55 can be reduced, and the liquid self-priming ability can be improved.

[Third Embodiment]
As shown in FIG. 12, the liquid reciprocating pump 1B according to the third embodiment is characterized in that a piston and a cylinder are used as the first flow path forming device, the second flow path forming device, and the suction flow path forming device. This is different from the liquid reciprocating pump 1 of the first embodiment. Since other configurations are the same, description thereof is omitted.
The first flow path forming device includes a first piston 545 connected to the first check valve 53 and a first cylinder 546 connected to the second check valve 55 and into which the first piston 545 is inserted. Composed.
The second flow path forming device includes a second piston 565 connected to the second check valve 55 and a second cylinder 567 connected to the discharge port member 57 and into which the second piston 565 is inserted. Is done.
The suction port-side flow path forming device includes a piston 525 coupled to the suction port member 51 and a cylinder 526 coupled to the first check valve 53 and into which the piston 525 is inserted.

The first piston 545 includes a first in-piston channel 5451 communicating with the first check valve 53 and the first cylinder 546. The first in-piston channel 5451 and the first cylinder 546 constitute a first channel.
The second piston 565 includes a second piston flow path 5651 communicating with the second check valve 55 and the second cylinder 567. The second piston flow path 5651 and the second cylinder 567 constitute a second flow path.
Further, the effective sectional areas of the first cylinder 546 and the second cylinder 567 are set to be the same.
The piston 525 includes an in-piston channel 5251 communicating with the channel 514 and the cylinder 526. The effective sectional area of the cylinder 526 is set to be the same as that of the cylinders 546 and 566.

  Also in the liquid reciprocating pump 1B, when the first check valve 53 and the second check valve 55 move up and down, the pistons 525, 545, and 565 move back and forth in the cylinders 526, 546, and 566, respectively. As a result, the volumes of the first flow path and the second flow path fluctuate, and a certain amount of liquid is continuously discharged as in the first embodiment.

  In the liquid reciprocating pump 1B of the third embodiment, pistons 525, 545, 565 and cylinders 526, 546, 566 are used as the first flow path forming device, the second flow path forming device, and the suction port flow path forming device. Therefore, the cost can be reduced as compared with the first embodiment using the bellows 52, 54, and 56.

[Fourth Embodiment]
As shown in FIG. 13, the liquid reciprocating pump 1C of the fourth embodiment is a liquid reciprocating pump of the first embodiment in that the first check valve 61 and the second check valve 65 are composed of double check valves. 1 and different. Since other configurations are the same, description thereof is omitted.

The first check valve 61 includes a check valve case 611, an upstream first check valve 62, and a downstream first check valve 63.
The upstream first check valve 62 includes a valve seat 622, a ball guide block 623, and a ball 624.
The downstream first check valve 63 includes a valve seat 632, a ball guide block 633, and a ball 634.
When the balls 624 and 634 come into contact with the valve seats 622 and 632, the first check valve 61 is closed. When the balls 624 and 634 move away from the valve seats 622 and 632, the first check valve 61 is opened, and the liquid flows through the communication holes of the valve seats 622 and 632 and the communication grooves of the ball guide blocks 623 and 633.

Similarly, the second check valve 65 includes a check valve case 651, an upstream second check valve 66, and a downstream second check valve 67.
The upstream second check valve 66 includes a valve seat 662, a ball guide block 663, and a ball 664.
The downstream second check valve 67 includes a valve seat 672, a ball guide block 673, and a ball 674.
When the balls 664 and 674 come into contact with the valve seats 662 and 672, the second check valve 65 is closed. When the balls 664 and 674 move away from the valve seats 662 and 672, the second check valve 65 is opened, and liquid flows through the communication holes of the valve seats 662 and 672 and the communication grooves of the ball guide blocks 663 and 673.

The fourth embodiment has the same operational effects as the first embodiment.
In addition, since the first check valve 61 and the second check valve 65 are each composed of a double check valve having two check valves, the opening and closing operation by the check valves 61 and 65 can be performed more reliably.
Moreover, since the downstream first check valve 63 and the downstream second check valve 67 are disposed in the first bellows 54 and the second bellows 56, the pump unit 5 can be prevented from being enlarged. Furthermore, if each check valve 61 and 65 is arrange | positioned in a flow path, the volume of each flow path can be made small and the self-priming capability of the pump part 5 can be improved.

In addition, this invention is not limited to the structure of the said Example, The deformation | transformation of the range which can achieve the objective of this invention is included in this invention.
For example, in the liquid reciprocating pump 1 according to the first embodiment, the suction port bellows 52 is disposed between the suction port member 51 and the first check valve 53, but instead of the suction port bellows 52, it is flexible. A sex tube may be used. This also applies to the liquid reciprocating pumps 1B and 1C.
That is, a member that can connect the fixed inlet member 51 and the first check valves 53 and 61 that move up and down may be used.

  As the check valves 53, 55, 61, and 65, a spring-loaded, reed valve type or the like may be used in addition to the gravity type ball valve as in the above embodiments. Further, when a gravity-type or spring-loaded ball valve is used, a double-layered valve may be used as in the fourth embodiment.

  In the above-described embodiment, the liquid is allowed to flow from below to above, but conversely, the liquid may be allowed to flow from above to below. In this case, since a gravity check valve cannot be used, a check valve with a spring may be used.

In the first, second, and fourth embodiments, instead of the inlet bellows 52, the first bellows 54, and the second bellows 56, a diaphragm may be used. Further, as in the third embodiment, a piston and a cylinder may be used, or a plunger and a plunger barrel may be used.
Further, the cam is not limited to the three-dimensional cam as in the above-described embodiment, and for example, two cams may be used. Further, the portion of the cam surface 21 other than the constant velocity motion is not limited to the constant acceleration cam of the above embodiment, and may be a cam surface of a cycloid curve.

  DESCRIPTION OF SYMBOLS 1,1A, 1B, 1C ... Reciprocating pump for liquids, 2 ... Drive part, 5 ... Pump part, 15 ... Motor, 20 ... Cam, 21 ... Cam surface, 31, 32 ... Drive shaft, 33, 34 ... Cam arm, 36: First drive arm, 37: Second drive arm, 52: Bellow for inlet, 53, 61: First check valve, 54: First bellow, 55, 65: Second check valve, 56: Second bellows , 70 ... Tank, 71 ... Liquid suction pipe, 511 ... Suction port member, 571 ... Discharge port member.

Claims (8)

A suction port member in which a liquid suction port is formed and a discharge port member in which a liquid discharge port is formed;
A pump unit provided between the suction port member and the discharge port member for sucking the liquid from the suction port and discharging the liquid from the discharge port;
A drive unit for driving the pump unit,
The pump part is
A first check valve communicated with the inlet;
A second check valve disposed on the outlet side with respect to the first check valve;
A first flow path forming device that forms a first flow path between the first check valve and the second check valve;
A second flow path forming device that forms a second flow path between the second check valve and the discharge port member,
The drive unit is
A first drive section for moving the first check valve in a first direction approaching the discharge port member side and a second direction approaching the suction port member side;
A second drive unit that moves the second check valve in a first direction approaching the discharge port member side and a second direction approaching the suction port member side;
The first flow path forming device and the second flow path forming device have the same effective cross-sectional area of each flow path, and expand and contract in the direction of each flow path as the first check valve and the second check valve move. The volume of each flow path can be changed,
The first driving unit and the second driving unit are
The second check valve is opened, and the first check valve is closed and moved in the first direction at a constant speed to reduce the volume of the flow path from the first flow path to the second flow path. A first step of discharging the liquid in the flow path from the discharge port;
The first check valve is opened, the second check valve is closed, and the first check valve is moved at a constant speed in the first direction to reduce the volume of the second flow path so that the liquid in the second flow path is reduced. Alternately repeating a second step of discharging from the discharge port and sucking liquid into the first flow path from the suction port via the first check valve,
The moving speed and moving amount of the first check valve in the first step in the first direction are the same as the moving speed and moving amount of the second check valve in the second step in the first direction ,
In the first step, the second check valve is moved to a position at the start of constant-velocity movement in the first direction of the second check valve in the second step,
In the second step, the first check valve is moved to a position at which the first check valve in the first step starts moving at a constant speed in the first direction in the first step. .   The reciprocating pump for liquid according to claim 1,
  The first driving unit and the second driving unit are
  In the first step, the second check valve moves in the first direction at a lower speed than the first check valve, then moves in the second direction, and further moves at a lower speed than the first check valve. Move in one direction, move to a position at the start of constant speed movement in the first direction of the second check valve in the second step,
  In the second step, the first check valve moves in the first direction at a lower speed than the second check valve, then moves in the second direction, and further moves at a lower speed than the second check valve. Move in one direction and move to a position at the start of constant-velocity movement in the first direction of the first check valve in the first step
  A reciprocating pump for liquid characterized by the above. In the reciprocating pump for liquid according to claim 1 or 2 ,
The first check valve is composed of two check valves, an upstream first check valve and a downstream first check valve,
The second check valve is composed of two check valves, an upstream second check valve and a downstream second check valve,
The downstream first check valve is disposed in the first flow path;
The downstream second check valve is disposed in the second flow path. A reciprocating pump for liquid, wherein In the liquid reciprocating pump according to any one of claims 1 to 3 ,
The first flow path forming device includes a first bellows connected to the first check valve and the second check valve,
The second flow path forming device includes a second bellows connected to the second check valve and the discharge port member,
The first bellows and the second bellows have the same effective cross-sectional area of the flow path. In the liquid reciprocating pump according to any one of claims 1 to 3 ,
The first flow path forming device includes a first piston connected to the first check valve, and a first cylinder connected to the second check valve and into which the first piston is inserted. And
The second flow path forming device includes a second piston connected to the second check valve, and a second cylinder connected to the discharge port member and into which the second piston is inserted. ,
The first piston includes a first piston flow path communicating with the first check valve and the first cylinder;
The second piston includes a second piston flow path communicating with the second check valve and the second cylinder,
The effective cross-sectional area of the said 1st cylinder and the said 2nd cylinder is the same. The reciprocating pump for liquids characterized by the above-mentioned. In the reciprocating pump for liquid according to any one of claims 1 to 5 ,
A reciprocating pump for liquid, wherein the suction port member and the first check valve are connected by a suction side flow path forming device. In the reciprocating pump for liquid according to any one of claims 1 to 5 ,
A container in which the liquid is stored;
A reciprocating pump for liquid, wherein the suction port member is constituted by a suction pipe having one end inserted into the container and the other end fixed to the first check valve. In the liquid reciprocating pump according to any one of claims 1 to 7 ,
The first driving unit includes:
A first drive arm to which the first check valve is fixed;
A first drive shaft to which the first drive arm is fixed;
A first cam arm fixed to the first drive shaft;
A first cam follower rotatably held by the first cam arm;
A cam having a cam surface against which the first cam follower abuts;
A rotational drive source for rotating the cam,
The second driving unit includes:
A second drive arm to which the second check valve is fixed;
A second drive shaft to which the second drive arm is fixed;
A second cam arm fixed to the second drive shaft;
A second cam follower rotatably held by the second cam arm;
A cam having a cam surface against which the second cam follower abuts;
A rotational drive source for rotating the cam,
Each of the cam followers is in contact with a position having a phase difference of 180 ° with respect to the cam surface.

Images