CN110552877A

CN110552877A - Plunger pump and liquid quantitative discharge device

Info

Publication number: CN110552877A
Application number: CN201910056993.7A
Authority: CN
Inventors: 千叶匡泰; 永井优宽; 高阶豪; 川添拓磨; 木村友亮
Original assignee: NAKA LIQUID CONTROL Co Ltd
Current assignee: NAKA LIQUID CONTROL Co Ltd
Priority date: 2018-05-30
Filing date: 2019-01-21
Publication date: 2019-12-10
Anticipated expiration: 2039-01-21
Also published as: KR20190136910A; KR102216471B1; CN110552877B; JP6392481B1; JP2019206946A

Abstract

The invention provides a plunger pump and a quantitative discharge device which can perform quantitative discharge with high precision. The plunger pump (20) is provided with: a pump body (24) in which a pump chamber (25) is formed; and a plunger that moves forward and backward relative to the pump chamber (25), wherein the pump body (24) is provided with: an introduction path (21) for introducing liquid into the pump chamber (25); a discharge passage (22) for discharging the liquid from the pump chamber (25); and an ejection passage (51) which is provided so as to communicate with the pump chamber (25) on one end side in the advancing/retreating direction of the plunger and which ejects the plunger from the pump chamber (25), wherein the ejection passage (51) has a passage width which allows the plunger to reciprocate and is substantially the same as the outer diameter of the plunger, and an exhaust port (52a) which is opened and closed by the reciprocation of the plunger is provided in a passage wall.

Description

Plunger pump and liquid quantitative discharge device

Technical Field

the present invention relates to a plunger pump and a liquid quantitative discharge device, and more particularly to a plunger pump and a liquid quantitative discharge device that perform quantitative discharge with high accuracy.

Background

Conventionally, there has been proposed a plunger pump including a pump body having a pump chamber formed therein and a plunger that moves forward and backward with respect to the pump chamber (for example, patent document 1). The plunger pump is provided with an introduction path for introducing a liquid into the pump chamber and a discharge path for discharging the liquid from the pump chamber, and a liquid storage container for storing the liquid is connected to the introduction path. When the pump chamber is filled with the liquid, the introduction path is closed, the discharge path is opened, and the plunger is advanced, whereby the liquid corresponding to the volume of the plunger inserted into the pump chamber is discharged from the discharge path of the pump chamber, and a fixed amount of the liquid is discharged. By closing the lead-out passage and opening the introduction passage, the plunger is retreated relative to the pump chamber to suck the liquid from the introduction passage.

In such a plunger pump, when gas (air) is mixed into the pump chamber, pressure is applied to the air when the plunger is moved forward into the pump chamber, and the volume decreases, so that a predetermined amount of liquid cannot be discharged from the pump chamber. In particular, air is often mixed when the liquid storage container connected to the introduction path of the plunger pump is replaced. Since the liquid storage container is temporarily removed at the time of replacement of the liquid storage container, a large amount of air enters the pump chamber from the lead-out passage. After the interior of the plunger pump is cleaned by maintenance or the like, air also enters when the pump chamber is filled with liquid.

In order to discharge the air mixed in the pump chamber, for example, a plunger pump shown in fig. 9 is provided with a discharge passage 3 for communicating the inside and the outside of the pump chamber 2 of the pump body 1. When the plunger pump is operated, the air discharge path 3 is used to perform an air discharge operation before a fixed-amount discharge operation. In the exhaust operation, first, the plug 6 that closes the exhaust path 3 is removed to set the exhaust path 3 in an open state in which it communicates with the outside, and the valve 4a of the liquid lead-out path 4 is set in a closed state. Then, the valve 5a of the introduction passage 5 is opened to introduce liquid from a liquid storage container (not shown) connected to the introduction passage 5 and to lead the liquid out of the gas discharge passage 3 via the pump chamber 2. At this time, the air in the pump chamber 2, the introduction passage 5, and the discharge passage 4 is also discharged from the pump chamber together with the liquid. When the operator visually confirms that air is not mixed into the liquid discharged from the opening of the exhaust passage 3, the introduction of the liquid is stopped, the liquid introduction passage 5 is closed, and the opening outside the exhaust passage 3 is closed by the plug 6.

As described above, when the exhaust operation is completed, the exhaust passage 3 is closed from the outside by the plug 6. However, there are problems as follows: when the plug 6 is closed, air enters the air discharge passage 3, and a predetermined amount of liquid cannot be discharged from the pump chamber, and the accuracy of the discharge of a predetermined amount is deteriorated.

documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2003-139073

disclosure of Invention

The present invention has been made in view of the above problems, and an object thereof is to provide a plunger pump and a liquid quantitative discharge device that perform quantitative discharge with high accuracy.

The present invention provides a plunger pump, which comprises: a pump body having a pump chamber formed therein; and a plunger that moves forward and backward with respect to the pump chamber, the pump body including: an introduction path for introducing liquid into the pump chamber; a discharge passage for discharging the liquid from the pump chamber; and an ejection passage which is provided so as to communicate with the pump chamber at one end side in a forward and backward direction of the plunger and which ejects the plunger from the pump chamber, wherein the ejection passage has a passage width which allows the plunger to reciprocate and is substantially the same as an outer diameter of the plunger, and an exhaust port which is opened and closed by the reciprocation of the plunger is provided in a passage wall.

According to the above configuration, during the air discharging operation, the plunger is moved in the retracting direction to open the air outlet of the retracting passage, thereby closing the lead-out passage and opening the lead-in passage. Then, the liquid is injected from the introduction path, passes through the pump chamber, and is discharged from the discharge port. At this time, the air accumulated in the pump chamber, the introduction passage, and the discharge passage is discharged from the discharge port together with the liquid. When the air is sufficiently discharged from the pump chamber, the plunger is advanced to a position where the exhaust port is closed, and the discharge operation is terminated by closing the discharge passage and the introduction passage.

In the fixed-quantity discharge operation, the plunger is advanced relative to the pump chamber from the position where the exhaust port is closed, with the lead-out passage opened and the lead-in passage closed. Then, the volume of the liquid of the plunger inserted into the pump chamber is led out from the lead-out passage of the pump chamber, and the liquid is discharged quantitatively. When the liquid is discharged, the plunger is retreated from the pump chamber to a position where the exhaust port is closed in a state where the lead-out passage is closed and the lead-in passage is opened. The above-described actions are repeated as many times as necessary.

The outer diameter of the plunger is substantially the same as the passage width of the ejection passage, and the exhaust port is closed by the plunger from the ejection passage side at the end of the exhaust operation. Therefore, air is not mixed into the pump chamber when the exhaust port is closed. Further, even when the air discharge hole communicating with the air discharge port is closed by the plug from the outside and air remains between the air discharge port and the plug, the air discharge port is closed by the plunger from the exit path side, and therefore the remaining air does not affect the quantitative discharge operation. Therefore, the constant-volume discharge can be performed with high accuracy.

In a preferred embodiment, the pump body is provided with the pump chamber having an inner diameter larger than an outer diameter of the plunger and a chamber provided continuously with the one end side of the pump chamber and having an inner diameter larger than the inner diameter of the pump chamber, and an assembly block having the ejection passage and the exhaust port is fitted into the chamber so that the ejection passage communicates with the pump chamber.

In this embodiment, the pump body is provided with an exhaust passage communicating with the chamber, and the assembly block is formed with an exhaust hole having the exhaust port and fitted so as to communicate with the exhaust passage.

In this embodiment, the assembly block may have an outer peripheral passage that circumferentially surrounds the outer peripheral surface, the withdrawal passage and the outer peripheral passage may communicate through the exhaust hole, and the outer peripheral passage may communicate with the exhaust passage.

in this embodiment, the exhaust port and the exhaust hole may be provided in plural numbers in the circumferential direction of the assembly block.

In this embodiment, it is preferable that a tapered portion whose passage width increases toward an end portion is formed at the pump chamber side end portion of the exit passage of the assembly block.

In this embodiment, the exhaust passage may be closed by a plug detachable from the outside of the pump main body.

In this embodiment, a seal member may be provided in the chamber, the seal member being continuous with the assembly block and being slidably fitted in close contact with the plunger.

The invention provides a liquid quantitative discharge device, comprising: the plunger pump; a first valve for opening and closing an introduction path of the plunger pump; a second valve that opens and closes a discharge passage of the plunger pump; a plunger driving mechanism that reciprocates the plunger; and a control device for controlling the reciprocating motion of the plunger and the opening and closing operations of the first valve and the second valve by the plunger driving mechanism, wherein the control device controls the first valve to open the introduction path and controls the second valve to close the introduction path during the air discharging operation, controls the plunger driving mechanism to retreat the plunger from the air outlet of the retreat path to open the air outlet, and controls the first valve to close the introduction path and controls the second valve to open the introduction path during the constant volume discharge operation to control the plunger driving mechanism to advance the plunger toward the pump chamber.

According to the above configuration, during the air discharging operation, the control device controls the first valve to open the introduction passage, controls the second valve to close the discharge passage, and controls the plunger driving mechanism to retract the plunger from the air outlet of the ejection passage, thereby opening the air outlet. Then, the liquid is injected from the introduction path, and is led out from the exhaust port through the pump chamber. At this time, the air accumulated in the pump chamber, the introduction passage, and the discharge passage is discharged from the discharge port together with the liquid. When the air is sufficiently discharged from the pump chamber, the plunger is advanced to a position where the exhaust port is closed, and the discharge passage and the introduction passage are closed, thereby ending the exhaust operation.

In the constant-volume discharge operation, the control device controls the first valve to close the introduction path, controls the second valve to open the discharge path, and controls the plunger driving mechanism to advance the plunger toward the pump chamber. The volume of the liquid of the plunger inserted into the pump chamber is led out from the lead-out passage of the pump chamber, and the liquid is discharged quantitatively. When the liquid is discharged, the second valve is controlled to close the discharge passage, the first valve is controlled to open the introduction passage, and the plunger driving mechanism is controlled to move the plunger backward from the pump chamber to a position where the exhaust port is closed. The above-described actions are repeated as many times as necessary.

The plunger and the outer diameter escape passage have substantially the same passage width, and the exhaust port is closed by the plunger from the escape passage side at the end of the exhaust operation. Therefore, when the exhaust port is closed, air does not enter the pump chamber. Further, even when the air vent hole communicating with the air vent hole is closed by the plug from the outside and air remains between the air vent hole and the plug, the air vent hole is closed by the plunger from the exit path side, and therefore the remaining air does not affect the quantitative discharge operation. Therefore, the constant-volume discharge can be performed with high accuracy.

Effects of the invention

According to the present invention, a constant-volume discharge can be performed with high accuracy.

Drawings

fig. 1 is a sectional view showing an overall configuration of a liquid quantitative discharge device according to an embodiment of the present invention;

Fig. 2 is a cross-sectional view showing a main part of the liquid quantitative discharge device in an enlarged manner;

FIG. 3 is a perspective view of the assembly block;

FIG. 4 is a block diagram showing a circuit configuration of a liquid quantitative discharge device;

FIG. 5 is a flowchart showing a flow of the air discharging operation;

Fig. 6A to 6F are explanatory views of the exhaust operation;

FIG. 7 is a flowchart showing a flow of a quantitative discharge operation;

FIGS. 8A to 8F are explanatory views of a quantitative discharge operation;

FIG. 9 is an explanatory view showing a prior art;

Detailed Description

embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, the advancing and retreating direction of the plunger 23 is referred to as the vertical direction in fig. 1, the advancing direction is referred to as the vertical direction, and the retreating direction is referred to as the vertical direction.

Fig. 1 to 4 show a liquid quantitative discharge device 10 according to an embodiment of the present invention. As shown in fig. 1 and 2, the liquid quantitative discharge device 10 includes: a plunger pump 20, a valve 12 (also referred to as a "first valve") for opening and closing an introduction passage 21 of the plunger pump 20, a valve 13 (also referred to as a "second valve") for opening and closing an introduction passage 22 of the plunger pump 20, a plunger driving mechanism 40 for reciprocating the plunger 23, and a control device 11 (fig. 4) for controlling the reciprocating movement of the plunger 23 and the opening and closing operations of the first valve 12 and the second valve 13 by the plunger driving mechanism 40. The type of liquid to be discharged from the liquid quantitative discharge device 10 is not particularly limited. In addition, the liquid also includes a liquid in a state where a solid is dispersed in the liquid.

The plunger pump 20 includes a pump body 24 having a pump chamber 25 formed therein, and a plunger 23 that moves forward and backward with respect to the pump chamber 25. The pump body 24 includes: a pump chamber 25 having an inner diameter larger than an outer diameter of the plunger 23 inside; an introduction path 21 for introducing liquid into the pump chamber 25; a discharge passage 22 for discharging the liquid from the pump chamber 25 to a position above the introduction passage 21; a chamber 26 which is provided continuously with the pump chamber 25 on one end side of the pump chamber 25 and on the upper side in fig. 1 and has an inner diameter larger than that of the pump chamber 25; and an exhaust passage 27 communicating with the chamber 26. The introduction passage 21, the discharge passage 22, and the exhaust passage 27 are provided in the pump body 24.

The upper end of the chamber 26 is open, and a substantially cylindrical assembly block 50 shown in fig. 3 is fitted through the opening. The assembly block 50 has a hollow portion penetrating from one end to the other end, i.e., vertically in fig. 1, and the hollow portion communicates with the pump chamber 25 to form an escape passage 51 for escaping the plunger 23 from the pump chamber 25. The exit passage 51 has a passage width in which the plunger 23 is reciprocable and is substantially the same as the outer diameter of the plunger 23. An exhaust port 52a is opened in the passage wall of the exit passage 51 at the center in the axial direction. The exhaust port 52a communicates with the exhaust hole 52, and communicates the exit passage 51 with an outer peripheral passage 54, which will be described later, via the exhaust hole 52. The exhaust port 52a is opened and closed by the reciprocating operation of the plunger 23.

In the present embodiment, 4 exhaust holes 52 are provided at equally spaced positions in the circumferential direction. The number of the exhaust holes 52 is not limited to 4, and may be 1, 2, 3, or 5 or more.

Two flange-like projecting members 53 projecting in the radial direction are provided around the circumference of the outer peripheral surface 50a of the assembly block 50. The space between the protruding members 53 constitutes an outer peripheral path 54, and the vent hole 52 is opened in the outer peripheral surface 50a between the protruding members 53, and the exit passage 51 and the outer peripheral path 54 communicate with each other through the opening 52 b. In a state where the assembly block 50 is fitted into the chamber 26, the outer peripheral passage 54 communicates with the exhaust passage 27 of the pump body 24. The air moving from the pump chamber 25 to the exit passage 51 moves from the exit passage 51 to the outer peripheral path 54 through the plurality of air discharge holes 52, and is discharged to the outside from the air discharge path 27 of the pump main body 24 through the outer peripheral path 54.

Flange members 55 in the form of flanges protruding in the radial direction around one circumference are formed at both axial end portions of the outer peripheral surface 50a of the assembly block 50. O-rings 56 for preventing the assembling block 50 from being misaligned and for preventing liquid from leaking from a gap between the assembling block 50 and the inner wall of the chamber 26 are installed in spaces between the flange part 55 and the protrusion part 53, respectively.

the diameter of the protruding member 53 and the flange member 55 is slightly smaller than the inner diameter of the chamber 26, and the assembly block 50 can be inserted into the chamber 26.

a tapered portion 57 is formed at an end portion of the exit passage 51 of the assembly block 50 on the pump chamber 25 side, the passage width of the exit passage 51 increasing toward the end portion, and the inner wall of the exit passage 51 is continuous with the inner wall of the pump chamber 25 via the tapered portion 57. The assembly block 50 is integrally molded of synthetic resin.

A seal member mounting block 28, which is continuous with the assembly block 50 and has a through hole 28c through which the plunger 23 slidably passes, is fitted in the chamber 26 of the pump body 24 above the assembly block 50. An annular seal member 28b into which the plunger 23 is slidably fitted in close contact is fitted into the seal member attachment block 28. The sealing member 28b is, for example, a spring packing, but is not limited thereto, and may be any sealing member 28b capable of preventing liquid from leaking to the outside from between the through hole 28c and the plunger 23. The seal member mounting block 28 has an O-ring 28a for preventing liquid leakage between the seal member mounting block 28b and the inner wall of the chamber 26.

A closing member 29 having a through hole 29a through which the plunger 23 slidably penetrates is attached to the upper side of the seal member attachment block 28 by a screw or the like, not shown, and the opening of the upper end of the chamber 26 of the pump main body 24 is closed by the closing member 29.

The plunger 23 reciprocates through the through hole 29a of the blocking member 29, the through hole 28c of the seal member mounting block 28, and the retreat path 51 of the assembly block 50, and the tip of the plunger 23 moves forward and backward with respect to the pump chamber 25 by the reciprocation.

A plug attachment member 30 having a detachable plug 31 is attached to a portion of the outer peripheral surface of the pump body 24 corresponding to the exhaust passage 27 by attachment means such as screw fastening, not shown. The plug attachment member 30 is formed with a plug attachment hole 32 communicating with the exhaust passage 27, and the exhaust passage 27 is closed by inserting a plug 31 into the plug attachment hole 32 from the outside. An O-ring 30a is provided between the plug attachment member 30 and the outer peripheral surface 50a of the pump body 24.

The first valve 12 is attached to a portion of the outer peripheral surface of the pump body 24 corresponding to the introduction passage 21, and opens and closes the introduction passage 21. The first valve 12 includes a first valve member 12a that opens and closes a passage 12c communicating with the introduction passage 21, and a first valve driving unit 12b (fig. 4) that drives the first valve member 12 a. The first valve 1 is, for example, a needle valve including a needle and an Actuator (not shown) such as a solenoid, but is not limited thereto, and may have any configuration capable of opening and closing the introduction passage 21. Not shown in the figure, the liquid storage container is connected to the inlet of the passage 12c of the first valve 12, and the liquid is introduced from the liquid storage container into the pump chamber 25 through the passage 12c of the first valve 12 and the introduction passage 21 of the pump body 24.

The second valve 13 is attached to a portion of the outer peripheral surface of the pump body 24 corresponding to the lead-out passage 22. The second valve 13 includes a second valve member 13a that opens and closes a passage 13c communicating with the lead-out passage 22, and a second valve driving unit 13b (fig. 4) that drives the second valve member 13 a. The second valve 13 is, for example, a needle valve including a needle and an actuator (not shown) such as a solenoid, but is not limited thereto, and may have any configuration capable of opening and closing the introduction passage 21. Although not shown in the figure, a nozzle portion for ejecting the liquid is connected to an outlet of the passage 13c of the second valve 13.

The plunger drive mechanism 40 includes a plunger drive unit 41 formed of a servo motor and a ball screw mechanism 43 connected to the plunger drive unit 41 via a power transmission mechanism 42. The ball screw mechanism 43 includes a ball screw to which the rotation of the plunger driving unit 41 is transmitted via the power transmission mechanism 42, a bearing to rotatably support the ball screw, a nut member screwed with the ball screw, and the like, and when the ball screw is rotated in any of the forward and reverse directions by the plunger driving unit 41, the plunger 23 and the nut member are integrally reciprocated in the rotational direction thereof.

The power transmission mechanism 42 is a mechanism for transmitting the rotation of the servo motor to the ball screw, and is composed of a first pulley 42a provided on an output shaft of the servo motor, a second pulley 42b provided on the ball screw 43a, and a belt 42c hung between the first pulley 42a and the second pulley 42 b.

As shown in fig. 2, the plunger drive mechanism 40 drives the plunger 23 so that the tip end of the plunger 23 is positioned at any of a home position P1, an exhaust start position P2, and an ejection completion position P3. The home position P1 is a position where the tip of the plunger 23 is positioned at the start and end of the air discharging operation of the liquid quantitative discharge device 10, at the start and end of the quantitative discharge operation, and when the tip of the plunger 23 is positioned at the home position P1, the exhaust port 52a of the ejection passage 51 is closed. In the present embodiment, the home position P1 is set to the same position as the lower end of the assembly block 50, but may be any position capable of closing the exhaust port 52 a.

The exhaust start position P2 is a position at which the exhaust port 52a of the exit passage 51 is opened, and is a position above the exhaust port 52a of the exit passage 51. The discharge completion position P3 is a predetermined position in the pump chamber 25. The discharge completion position P3 is determined according to the type of liquid discharged from the constant-volume liquid discharge device 10, a desired discharge amount, the diameter of the plunger 23, and the like, and is stored in the storage unit of the control device 11 shown in fig. 4 as a predetermined distance L from the home position P1 of the plunger 23 to the discharge completion position P3.

The control device 11 includes a control unit, a storage unit, and an interface unit, which are not shown. The control unit is configured by, for example, a CPU and a memory serving as a work area, and executes a program stored in the storage unit to control the operations of the plunger driving unit 41, the first valve driving unit 12b, and the second valve driving unit 13b, which are servo motors. The storage unit is configured by a storage device such as a flash memory or a nonvolatile memory, and stores a program executed by the control unit. The storage unit stores the number of times of the constant-volume discharge operation, and the distance L by which the plunger 23 is moved from the home position P1 to the discharge completion position P3 during the constant-volume discharge operation. The interface unit includes an input port for receiving a signal, an output port for transmitting a signal, an a/D conversion circuit, and the like, and is used to connect the plunger drive unit 41, the first valve drive unit 12b, the second valve drive unit 13b, and the control device 11. The control device 11 and the plunger driving unit 41, and the first valve driving unit 12b and the second valve driving unit 13b are connected by cables to transmit and receive control signals, but the control device 11, the plunger driving unit 41, the first valve driving unit 12b, and the second valve driving unit 13b may each include a communication unit to transmit and receive control signals wirelessly.

An input device 14, for example, a touch panel or the like, is connected to the control device 11, and an operator can input an instruction to the control device 11 via the input device 14. In addition, when the input device 14 also serves as a display device such as a display, the driving state of the plunger driving unit 41 controlled by the control device 11 and the open/close states of the first valve 12 and the second valve 13 can be displayed.

next, the operation of the liquid quantitative discharge device 10 according to the present embodiment will be described with reference to fig. 5 to 8. The liquid quantitative discharge device 10 is a device that performs a quantitative discharge operation of the liquid, but after the inside of the liquid quantitative discharge device 10 is cleaned by maintenance or the like and after the liquid storage container is replaced, since air is present inside the liquid quantitative discharge device 10, an air discharge operation is performed before the quantitative discharge operation of the liquid.

fig. 5 is a flowchart for explaining the operation of the control device 11 during the exhaust operation, and fig. 6A to 6F are explanatory diagrams showing the position of the plunger 23, the open/close states of the first valve 12 and the second valve 13, and the attachment state of the plug 31. In fig. 6, the liquid quantitative discharge device 10 is shown in a simplified manner for the sake of explanation.

The exhaust action starts with the first valve 12 being open, the second valve 13 being closed, and the plunger 23 being at the home position P1. However, after the inside of the liquid quantitative discharge device 10 is cleaned by maintenance or the like, or after the liquid storage container is replaced, the first valve 12, the second valve 13, and the plunger 23 may not be in the state at the start of the air discharge operation. Therefore, when the operator inputs a command to start the exhaust operation from the input device 14, at ST10 in fig. 5, the controller 11 checks whether or not the first valve 12 is open, the second valve 13 is closed, and the plunger 23 is in the state of the home position P1, and if this state is not achieved, the controller controls the first valve driver 12b to open the first valve 12, controls the second valve driver 13b to close the second valve 13, and controls the plunger driver 41 to move the plunger 23 to the home position P1 (fig. 6A). Next, the operator removes the plug 31 of the plug attachment member 30 (fig. 6B), and inputs a command to the control device 11 to complete the removal of the plug 31 from the input device 14. In ST11, when the control device 11 receives the command to complete the removal of the plug 31, the process proceeds to ST 12. If the command for completion of the removal of the plug 31 is not received, ST11 is repeated until the command is received. Further, a sensor may be attached which detects whether or not the plug 31 is attached to the plug attachment member 30. In this case, when the control device 11 receives a signal indicating that the plug 31 is detached from the plug attachment member 30 from the sensor, the process proceeds to ST 12.

In ST12, the controller 11 drives the plunger driving unit 41 to retract the plunger 23 to the exhaust start position P2 (fig. 6C). Then, the liquid is introduced from the liquid storage container into the pump chamber 25 through the first valve 12, passes through the exit passage 51 of the assembly block 50, flows around the outer peripheral path 54 of the assembly block 50 from the plurality of vent holes 52 provided in the exit passage 51, and is discharged to the outside through the vent passage 27 of the pump body 24 and the plug mounting hole 32 of the plug mounting member 30. At this time, the air is also discharged to the outside together with the liquid. A liquid receiving unit such as a liquid receiving container, not shown, is disposed near the opening of the plug attachment hole 32, and the liquid receiving container receives liquid discharged to the outside. In this case, the other end of the tube is attached to the opening of the plug attachment hole 32, and the liquid discharged to the outside is accommodated in the container through the tube.

When the operator visually confirms that air is not mixed in the liquid discharged from the exhaust passage 27, an instruction to end the exhaust operation is input from the input device 14 to the control device 11. In ST13, when the control device 11 receives the command for ending the air discharging operation, the process proceeds to ST 14. If the command for ending the air discharging operation is not received, the control device 11 repeats ST 13.

In ST14, the control device 11 controls the plunger driving unit 41 to move the plunger 23 to the home position P1 (fig. 6D). The operator mounts the plug 31 of the plug mounting member 30 (fig. 6E), and inputs a command for completion of mounting the plug 31 from the input device 14 to the control device 11. In ST15, when the controller 11 receives the command to complete the attachment of the plug 31, the process proceeds to ST 16. If the command for completion of the installation of the plug 31 is not received, ST15 is repeated until the command is received. Further, a sensor may be attached which detects whether or not the plug 31 is attached to the plug attachment member 30. In this case, when the control device 11 receives a signal indicating that the plug 31 is attached from the plug attachment member 30 from the sensor, the process proceeds to ST 16.

In ST16, the control device 11 drives the first valve driving unit 12b to close the first valve 12 (fig. 6F), and the exhaust operation is completed.

Next, the operation of the controller 11 in the constant-volume liquid discharge operation of the constant-volume liquid discharge device 10 will be described. Fig. 7 is a flowchart for explaining the fixed-quantity discharge operation, and fig. 8A to 8F are explanatory diagrams showing the position of the plunger 23, the open/close states of the first valve 12 (valve member 12a) and the second valve 13 (valve member 13a), and the attachment state of the plug 31 during the fixed-quantity discharge operation. Fig. 8 is a simplified illustration of the liquid quantitative discharge device 10 for the sake of explanation.

In ST31 of fig. 7, the control device 11 confirms that the first valve 12 and the second valve 13 are closed and the plunger 23 is at the home position P1 (fig. 8A). When the first valve 12 and the second valve 13 are not closed and the plunger 23 is not at the home position P1, the controller 11 controls the first valve driver 12b and the second valve driver 13b to close the first valve 12 and the second valve 13 and controls the plunger driver 41 to move the plunger 23 to the home position P1.

In ST32, the control device 11 controls the second valve driving part 13B to open the second valve 13 (fig. 8B). In ST33, the controller 11 moves the plunger 23 forward by a predetermined distance L and moves the distal end of the plunger 23 to the discharge completion position P3 (fig. 8C). The liquid corresponding to the volume of the plunger 23 entering the pump chamber 25 is discharged from the discharge passage 22 through the passage 13c of the second valve 13 from a nozzle portion not shown. In ST34, the control device 11 controls the second valve driving unit 13b to close the second valve 13 (fig. 8D). In ST35, the control device 11 controls the first valve driving unit 12b to open the first valve 12 (fig. 8E). In ST36, the control device 11 controls the plunger driving unit 41 to move the plunger to the home position P1 (fig. 8F). Thereby, the liquid is drawn to the pump chamber 25 through the first valve 12. In ST37, the control device 11 controls the first valve driving unit 12b to close the first valve 12 (fig. 8A). In ST38, the control device 11 determines whether or not the constant-volume discharge operation has been performed a predetermined number of times. If not, the process returns to ST 32. When the predetermined number of times is performed, the constant-volume discharge operation is ended.

According to the above embodiment, even when air enters when the plug 31 is attached and air remains between the plug 31 and the air outlet 52a during the air discharging operation, the air outlet 52 is always closed by the plunger 23 and does not communicate with the pump chamber 25 during the constant-volume discharging operation, and therefore, the remaining air does not affect the discharge amount and constant-volume discharging with high accuracy can be performed.

further, according to the above embodiment, since the assembly block 50 in which the escape passage 51 and the exhaust port 52a are formed is fitted into the pump body 24, the assembly block 50 can be removed at the time of maintenance, and maintenance is easier than in the case where the escape passage 51 and the exhaust port 52a are formed in the pump body 24.

since the air discharge passage 27 and the air discharge hole 52 communicate with each other via the outer peripheral path 54 even if the air discharge hole 52 of the assembly block 50 is not disposed at a position corresponding to the air discharge path 27 of the pump main body 24, the outer peripheral path 54 through which air can pass is formed on the outer peripheral surface 50a of the assembly block 50, and therefore, air can be discharged from the pump main body 24 by moving the air from the exit passage 51 of the assembly block 50 to the air discharge path 27 of the pump main body 24 via the air discharge hole 52 and the outer peripheral path 54.

Since the plurality of exhaust ports 52a are provided in the circumferential direction of the assembly block 50, air is easily discharged from the exit passage 51 of the assembly block 50.

In addition, in the case where the plurality of air discharge passages 27 are directly provided in the pump body 24 without using the assembly block 50, it is necessary to provide the plug attachment member 30 for each air discharge passage 27, and it is necessary to dispose a liquid receiving unit such as a liquid receiving container near each plug attachment member 30 to receive liquid. However, since the valves 12, 13, and the like are provided on the outer peripheral surface of the pump main body 24, there is not sufficient space for disposing a plurality of liquid receiving units. However, in the present embodiment, since the plurality of exhaust ports 52a are provided in the assembly block 50 and the 1 exhaust path 27 is provided in the pump main body 24, the air in the exit path 51 is discharged from the plurality of exhaust ports 52 to the exit path 51 and is discharged to the outside from the exhaust path 27 of the pump main body 24 through the outer peripheral path 54, the air is easily discharged from the exit path 51, and it is not necessary to provide a plurality of liquid receiving units on the outer peripheral surface of the pump main body 24, thereby saving space. Further, since the pump main body 24 is provided with 1 exhaust passage 27, the structure of the pump main body 24 is simpler than the case where a plurality of exhaust passages 27 are provided.

In the exit passage 51 of the assembly block 50, the tapered portion 57 whose passage width increases toward the end portion is formed at the end portion on the pump chamber 25 side, and therefore, it is possible to prevent a step from being generated between the assembly block 50 and the pump chamber 25 and air from being trapped at the step.

Since the exhaust passage 27 of the pump body 24 is closed by the plug 31 detachable from the outside of the pump body 24, the liquid can be prevented from flowing out during the quantitative discharge operation.

While one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the present invention.

Description of the symbols

10 liquid quantitative discharge device

11 control device

12 first valve

13 second valve

20 plunger pump

21 introduction path

22 lead-out path

23 plunger

24 pump body

25 pump chamber

26 chamber

27 exhaust path

28 sealing member

31 bolt

40 plunger driving mechanism

50 assembling block

50a outer peripheral surface

51 exit path

52 exhaust port

52 vent hole

56O-ring

54 peripheral road

57 taper part

Claims

1. A plunger pump is provided with:

a pump body having a pump chamber formed therein; and

A plunger which moves forward and backward relative to the pump chamber,

The pump main body is provided with:

An introduction path for introducing liquid into the pump chamber;

A discharge passage for discharging the liquid from the pump chamber; and

An ejection passage which is provided so as to communicate with the pump chamber on one end side in a forward/backward direction of the plunger and which ejects the plunger from the pump chamber,

The ejection passage has a passage width that enables the plunger to reciprocate and is substantially the same as the outer diameter of the plunger, and an exhaust port that is opened and closed by the reciprocation of the plunger is provided in a passage wall.

2. the plunger pump of claim 1,

The pump main body is provided with:

the pump chamber having an inner diameter larger than an outer diameter of the plunger; and

A chamber provided continuously with the one end side of the pump chamber and having an inner diameter larger than an inner diameter of the pump chamber,

An assembly block having the exit passage and the exhaust port is fitted in the chamber so that the exit passage communicates with the pump chamber.

3. The plunger pump of claim 2,

the pump body is provided with an exhaust passage communicating with the chamber,

The assembly block is formed with an exhaust hole having the exhaust port, and the assembly block is fitted so that the exhaust hole communicates with the exhaust passage.

4. The plunger pump of claim 3,

The assembly block has an outer peripheral passage that circumferentially surrounds the outer peripheral surface, the exit passage is communicated with the outer peripheral passage through the exhaust hole, and the outer peripheral passage is communicated with the exhaust passage.

5. The plunger pump of claim 2,

The exhaust port and the exhaust hole are arranged in a plurality along the circumferential direction of the assembly block.

6. The plunger pump of claim 2,

In the exit passage of the assembly block, a tapered portion is formed at an end portion on the pump chamber side, the tapered portion having a passage width that increases toward the end portion.

7. the plunger pump of claim 2,

The exhaust path is closed by a plug that is detachable from the outside of the pump body.

8. the plunger pump of claim 2,

A seal member is provided in the chamber, the seal member being continuous with the assembly block and slidably fitted in close contact with the plunger.

9. A liquid quantitative discharge device includes:

The plunger pump of any one of claims 1 to 8;

A first valve for opening and closing an introduction path of the plunger pump;

A second valve that opens and closes a discharge passage of the plunger pump;

A plunger driving mechanism that reciprocates the plunger; and

A control device for controlling the reciprocating motion of the plunger and the opening and closing operations of the first valve and the second valve by the plunger driving mechanism,

as far as the control device is concerned,

In the exhaust operation, the first valve is controlled to open the introduction passage, the second valve is controlled to close the discharge passage, and the plunger driving mechanism is controlled to retract the plunger from the exhaust port of the ejection passage to open the exhaust port,

in the fixed-amount discharge operation, the first valve is controlled to close the introduction passage, the second valve is controlled to open the discharge passage, and the plunger driving mechanism is controlled to advance the plunger toward the pump chamber.