JPH1047234A - Quantitative delivery pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a quantitative delivery pump which is compact and has agreeable air vent. SOLUTION: A quantitative delivery pump has a pump housing 11 in which a pump chamber 10 with bellows 16, a connecting path 17a and communicating path 15a for guiding liquid in a liquid storing tank 8 to the pump chamber 10 and a communicating path 15b and connecting path 17b for guiding the liquid in the pump chamber 10 to a liquid delivery part 9 are mounted. Diaphragms 13a, 13b disposed between the connecting path 17a and 17b and the communicating path 15a and 15b for switching between them are mounted in the pump housing 11 and valves 21a, 21b in which its valve chambers 19a, 19b are formed in the pump body 11 are included. A valve housing 22 in which pilot parts 20a, 20b for driving the diaphragms 13a, 13b are disposed is also included in the pump and the valves 21a, 21b and the pump chamber 10 are unitarily arranged by mounting this valve housing 22 and the pump housing 11 unitarily.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixed-rate discharge pump, and more particularly, to a technique which is effective when applied to a fixed-rate discharge pump using an operate valve during a suction / discharge operation.

[0002]

2. Description of the Related Art Conventionally, a fixed-rate discharge pump has been widely used for supplying a predetermined amount of a chemical solution, a solution, a cleaning solution, or the like to an apparatus for manufacturing electronic parts such as semiconductors.

[0003] As this fixed-rate discharge pump, a bellows pump that obtains a suction pressure and a discharge pressure by expanding and contracting a bellows is widely used. In this case, the expansion and contraction of the bellows is generally controlled by a motor and air pressure. For example, in the liquid ejection apparatus disclosed in Japanese Patent Application Laid-Open No. 7-310838, the expansion and contraction of the bellows is performed by a combination of a motor and a ball screw. Also, JP-A-62-2334.
In the bellows pump of Japanese Patent No. 85 and the double-acting pump of Japanese Patent Application Laid-Open No. 3-78583, two bellows are alternately expanded and contracted by air pressure to suck and discharge liquid.

On the other hand, in this type of fixed-rate discharge pump, a check valve is disposed before and after the pump chamber for sucking and discharging liquid, and a so-called self-weight check valve is usually used as the check valve. Is often done. However, when the tip end position of the nozzle on the discharge side is lower than the liquid storage tank on the suction side, the liquid naturally flows out of the liquid storage tank due to the siphon principle in the self-weight check valve. When it is desired to return the liquid to the storage tank side, the self-weight check valve cannot be used.

Therefore, in such a case, air operated valves (hereinafter simply referred to as valves) 51 and 52 as shown in FIG.
The forcible opening and closing of the valve prevents the natural outflow of liquid and allows the liquid to flow back to the storage tank.

Here, the structure and operation of the fixed-rate discharge pump 50 shown in FIG. 4 will be briefly described. The fixed-rate discharge pump 50 comprises a pump body 54, valves 51 and 52, and connection tubes 62 and 63 connecting these. The valves 51 and 52 control opening and closing of the inflow-side flow path 55 and the discharge-side flow path 56. In this case, the valves 51, 5
Reference numeral 2 denotes a so-called diaphragm valve for operating the diaphragm 57 by the air cylinder 58, and both have the same structure. A pump chamber 53 is formed in the pump body 54, and a bellows 59 is disposed therein. The suction pressure and the discharge pressure are obtained in the pump chamber 53 by moving the bellows 59 forward and backward.

[0007] A fixed-rate discharge pump 5 having such a configuration.
In the case of 0, when sucking the liquid from the liquid storage tank (not shown), first, the air cylinder 58 of the valve 51 is operated to retract the piston 60 and pull up the diaphragm 57. Thereby, the valve 51 is opened, and the pump chamber 53 and the liquid storage tank are communicated. The valve 52 is kept closed by the urging force of the spring 61. Then, in this state, the bellows 59 is retracted. As a result, a suction pressure is generated in the pump chamber 53, and the liquid in the liquid storage tank flows into the pump chamber 53 via the inflow side flow path 55 and the connection tube 62. When a predetermined amount of liquid flows into the pump chamber 53, the bellows 59 is stopped and the piston 60 is advanced to close the valve 51. FIG. 4 shows this state.

When the pump chamber 53 is filled, the valve 52 is opened. At this time, the valve 51 is kept closed. Then, the bellows 59 is advanced in a direction opposite to the above. As a result, a discharge pressure is generated in the pump chamber 53, and the liquid therein is supplied to a liquid discharge nozzle (not shown) via the connection tube 63 and the discharge-side flow path 56. Thereafter, the valve 52 is closed, thereby completing one suction / discharge operation.

As described above, this type of conventional fixed-rate discharge pump 50 comprises a pump body 54 and two valves 51 and 52. By controlling the opening and closing of the valves 51 and 52, a predetermined amount of a chemical solution or the like is manufactured in a semiconductor. It is supplied to equipment.

[0010]

However, in such a conventional fixed-rate discharge pump, the pump main body and the valve are separately provided, and a tube and a joint for connecting the pump and the valve are required. For this reason, there has been a problem that the system is complicated and the number of parts is large, and the reliability tends to be low. In addition, since there are many components, the liquid contact portion increases accordingly, and there is also a problem that a large amount of liquid stays and dust is generated.

On the other hand, as can be seen from FIG.
In Nos. 1 and 52, since the diaphragm 57 operates in the vertical direction, bubbles in the liquid tend to accumulate upward in the valve, and there is also a problem that bubble removal is poor.

An object of the present invention is to provide a fixed-volume discharge pump which is compact and has good bubble removal.

The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0014]

SUMMARY OF THE INVENTION Among the inventions disclosed in the present application, the outline of a representative one will be briefly described.
It is as follows.

That is, the fixed-rate discharge pump according to the present invention is provided with a reciprocating member which moves forward and backward in the axial direction, and a pump chamber which generates suction pressure and discharge pressure by the reciprocating movement of the reciprocating member; A pump housing is first provided with a first flow path for guiding the liquid to the pump chamber and a second flow path for guiding the liquid in the pump chamber to the liquid discharge unit.
A first valve device is provided in the pump housing, the valve body being provided in the first flow passage and opening and closing the first flow passage, and the valve chamber is formed in the pump housing. And a second valve device in which a valve body for opening and closing the second flow path is provided in the pump housing and a valve chamber thereof is formed in the pump housing. Further, it has a valve housing provided with a pilot portion for driving each valve element of the first valve device and the second valve device, respectively. By providing this valve housing integrally with the pump housing, the first
The valve device and the second valve device are provided integrally with the pump chamber.

In this case, the first flow path is connected to the center of the first valve device and extends from the upper part of the valve chamber of the first valve device to the lower part of the pump chamber. May be connected from the upper part to the center of the second valve device and may be connected to the liquid discharge part from the upper part of the valve chamber of the second valve device. It is also characterized by flowing horizontally or upwards.

Further, the reciprocating member may be a bellows which operates in the same direction as the operation direction of the valve element, and the valve element may be a diaphragm.

[0018]

Embodiments of the present invention will be described below in detail with reference to the drawings. 1 to 3 are cross-sectional views showing a configuration of a fixed-rate discharge pump according to one embodiment of the present invention. 1 is a cross-sectional view showing the overall configuration, FIG. 2 is an enlarged cross-sectional view of a main part in FIG. 1, and FIG. 3 is a partial cross-sectional view along the line AA in FIG. The metering discharge pump of the present invention,
The pump body and the operating valve are integrated to reduce the size of the liquid-contacting part and reduce the amount of liquid contact, and also to improve the bubble removal by stabilizing the flow direction of the liquid.

As shown in FIG. 1, the fixed-rate discharge pump includes a pump chamber 10 and an air operated diaphragm valve (hereinafter abbreviated as a valve) 21a (first valve device), 21b.
(Second valve device) Pump section 1 in which valve chambers 19a and 19b are formed, and pilot section 2 of valves 21a and 21b
It comprises a valve section 2 in which Oa and 20b are arranged, and a drive section 3 in which a drive system such as a motor 31 is housed. Then, the valve housing 22 of the valve unit 2, the pump housing 11 of the pump unit 1, and the housing 32 of the drive unit 3 are connected to each other by using fastening members (not shown) such as bolts arranged in the left-right direction in FIG. By fastening, it is assembled as a fixed-rate discharge pump. In the following description, the suffix a of the reference numeral indicates a member on the inflow side, and b indicates a member on the discharge side.

Here, the pump housing 1 of the pump section 1
As shown in FIGS. 1 and 2, a pump chamber 10 in which the drive unit 3 side is sealed by a bellows fixing ring 18 is formed in 1, and a bellows formed integrally with the bellows fixing ring 18 is formed therein. A bellows 16 (reciprocating member) is housed. Further, the bellows 16 has its tip end 16 h fixed to a drive shaft 33 extending from the drive unit 3 side. Therefore, by moving the drive shaft 33 forward and backward, the bellows 16 expands and contracts in the pump chamber 10. As a result, suction pressure and discharge pressure are generated.

Further, diaphragm mounting portions 12a and 12b are formed on the side surface of the pump housing 11 on the valve portion 2 side, and the diaphragms 13a and 13b constituting the valve bodies of the valves 21a and 21b are fixed thereto. It is attached by rings 14a, 14b. In this case, the diaphragm fixing rings 14a, 14b are connected to the diaphragms 13a, 13b together with the valve bodies 27a, 27b.
And the diaphragm mounting portion 12a,
12b are attached in an integrated state. The pump housing 11, the bellows fixing ring 18, the bellows 16, the diaphragm 1
3a, 13b, etc. are made of polytetrafluoroethylene (PT) which is a fluororesin in consideration of corrosion resistance due to a chemical solution or solution.
It is formed of a synthetic resin such as FE).

On the other hand, communication paths 15a (first flow path) and 15b (second flow path) are provided between the pump chamber 10 and the diaphragm mounting portions 12a and 12b, respectively. Further, connection paths 17a (first flow path) and 17b (second flow path) are also provided between the diaphragm mounting portion 12a and the inflow side flow path 4 and between the diaphragm mounting portion 12b and the discharge side flow path 5, respectively. Is provided. The inflow-side flow path 4 is connected to the liquid storage tank 8, and the discharge-side flow path 5 is connected to the liquid discharge unit 9.

In this case, the connection path 17a is connected to the center of the diaphragm mounting portion 12a, that is, to the center of the valve 21a. The communication passage 15a is located above the diaphragm mounting portion 12a, that is, the valve chamber 1 of the valve 21a.
It exits from the upper part of 9a and is connected to the lower part of the pump chamber 10. Further, the communication path 15b exits from the upper part of the pump chamber 10 and is connected to the center of the valve 21b. The connection path 17b exits from the upper part of the valve chamber 19b of the valve 21b and is connected to the discharge side flow path 5b.
It is connected to the. As described above, the fixed-rate discharge pump is configured such that the sucked liquid always flows upward without turning the flow direction in the valve chambers 19a and 19b. Therefore, the valve chambers 19a, 19b
As compared with the conventional fixed-rate discharge pump in which the flow direction of the liquid is turned up and down inside, there is no stagnation of bubbles, and the bubble removal property is improved.

Next, in the valve housing 22 of the valve section 2,
As shown in FIGS. 1 and 2, two cylinder holes 23
a and 23b are formed therein, and the valves 21a and 2b are provided therein.
1b are configured as pilot sections 20a and 20b.
That is, the pistons 24a, 24b and the guide washers 28a,
28b are accommodated, and the cylinder holes 23a, 23
b and the guide washers 28a and 28b define cylinder chambers 25a and 25b. And the piston 24
A and 24b are driven in the left and right directions in the cylinder chambers 25a and 25b while being guided by guide washers 28a and 28b. Springs 26a and 26b are provided in the cylinder chambers 25a and 25b, respectively.
a and 24b are constantly urged toward the pump unit 1 side. Accordingly, the pistons 24a and 24b are in the cylinder chamber 2 during the steady state.
It stops at the right end side of 5a, 25b and moves to the left side in the figure when air is introduced. As can be seen from FIG. 3, the supply and discharge of air to and from the cylinder chamber 25b are performed as follows.
The operation is performed through the supply / exhaust passage 29b and the exhaust port 30b, and the same applies to the cylinder chamber 25a.

Further, valve bodies 27a, 27b formed integrally with the diaphragms 13a, 13b are attached to the distal ends of the pistons 24a, 24b, whereby the diaphragms 13a, 13b are driven in the left-right direction in FIG. . Therefore, when air is not introduced into the cylinder chambers 25a, 25b, the diaphragms 13a, 13b
Is connected to the connection passage 17a and the communication passage 15b together with the valve bodies 27a and 27b by the elastic force of the springs 26a and 26b.
To close these channels. On the other hand, when air is introduced into the cylinder chambers 25a and 25b, the pistons 24a and 24b are retracted to the left in the drawing, and the diaphragms 13a and 13b are connected to the connection path 17a and the communication path 1a.
These flow paths are opened by separating from the opening 5b.

In the constant-rate discharge pump of the present invention, the operating axes of the diaphragms 13a and 13b are set in the same direction as that of the bellows 16 (horizontal direction in the figure). For this reason, the direction in which the diaphragms 13a and 13b are fixed together with the diaphragm fixing rings 14a and 14b,
The direction in which 6 is fixed together with the bellows fixing ring 18 is the same direction. Therefore, when the pump housing 11 and the valve housing 22 are fastened together,
Tightening can be performed using common fastening parts, and the pump structure can be simplified.

Further, in the fixed-rate discharge pump according to the present invention, since the liquid-contacting portion is formed in the pump housing which must be formed of a corrosion-resistant material, the material of the valve housing 22 is particularly considered to be corrosion-resistant. do not have to. For this reason, in the present embodiment, the valve housing 22 and the like are formed of a synthetic resin such as vinyl chloride in view of the fact that it is lightweight and easy to manufacture. However, the piston 24
Light metals such as aluminum may be adopted for the a and 24b and the guide washers 28a and 28b in consideration of durability and aging.

On the other hand, the housing 32 of the drive unit 3
A drive system device such as 1 is provided, and is fastened to the pump housing 11 via a connection plate 7 having a wear ring 6 that slides on a drive shaft 33 as shown in FIG. Here, the drive unit 3 includes a drive shaft 33 connected to the bellows 16, a ball screw nut 34 fixed to the drive shaft 33, a ball screw 35 screwed with the nut, and a motor 31 for rotating the ball screw 35. And a configuration including In this case, the ball screw 35 is driven by a belt by the motor 31, and both are connected by pulleys 36 and 37 and a belt 38. Also, the ball screw 35
Is connected to the pulley 37 while being supported by the bearing 39. Further, the drive shaft 33 includes a guide shaft 41
Via a guide bush 42.

As described above, in the driving section 3, the ball screw 35 is rotated by the rotation of the motor 31, so that the driving shaft 33 is moved forward and backward in the left and right direction in the drawing while being guided by the guide shaft 41. It has become. Then, the bellows 16 expands and contracts, and suction / discharge pressure is generated in the pump chamber 10. Note that an encoder 43 is attached to the motor 31 so that the rotation angle and the number of rotations thereof can be accurately measured. Also,
The position of the drive shaft 33 can also be detected by the sensor 44. In the present application, the rotation of the motor means a forward / reverse operation of the motor including a displacement of 360 degrees or more.

Next, a description will be given of the operation in the case of supplying a liquid in the fixed-rate discharge pump having such a configuration.

The liquid suction / discharge operation itself of the fixed-rate discharge pump is basically the same as the operation described in the example of the conventional fixed-rate discharge pump. However, in the fixed-rate discharge pump, the flow direction of the liquid does not reverse up and down, and the flow path length is short.

First, when sucking the liquid from the liquid storage tank 8, first, the valve 21a is operated to operate the piston 24a.
Is retracted, and the diaphragm 13a is separated from the opening of the connection path 17a. As a result, the valve 21a is opened, and the pump chamber 10 and the liquid storage tank 8 communicate with each other. The valve 21b is kept closed by the urging force of the spring 26b. Then, in this state, the bellows 16 is retracted. That is, the motor 31 is operated to rotate the ball screw 35, and the drive shaft 33 is moved backward. As a result, a suction pressure is generated in the pump chamber 10, and the liquid in the liquid storage tank 8 flows into the inflow-side flow path 4, the connection path 17a, and the communication path 15a.
Flows into the pump chamber 10 via And pump room 1
When a predetermined amount of liquid flows into the valve 0, the movement of the bellows 16 is stopped, and the piston 24a is advanced so that the diaphragm 13a is pressed against the opening of the connection path 17a, and the valve 21 is closed.
Close a. FIG. 1 shows this state.

On the other hand, when the pump chamber 10 is filled, the valve 21b is opened by the same operation as described above. At this time, the valve 21a is maintained in the closed state. Then, the motor 31 is reversed and the bellows 16
To move forward. As a result, a discharge pressure is generated in the pump chamber 10, and the liquid therein is supplied to the liquid discharge unit 9 via the communication path 15b, the connection path 17b, and the discharge-side flow path 5. Thereafter, the valve 21b is closed, whereby one suction / discharge operation is completed.

Here, looking at the flow of the liquid in a series of suction / discharge operations, first, the liquid enters the connection path 17a from the inflow side flow path 4 and bends at right angles to the center of the valve 21a. In the valve 21a, the flow turns upward, and flows upward again from the upper part in the communication path 15a to bend upward and reach the pump chamber 10. Next, the liquid is discharged horizontally from the pump chamber 10 into the communication passage 15b and enters the center of the valve 21b. Then, the flow is turned upward at the valve 21b,
After flowing in the connection path 17b in the horizontal direction again from the upper part, it turns upward and reaches the discharge side flow path 5. That is, in the fixed-rate discharge pump, the liquid always flows upward or horizontally, and there is no place where the flow turns up and down. For this reason, there is no inflection point at which bubbles in the liquid stay, and there is a characteristic that bubbles are very good.

Although the invention made by the inventor has been specifically described based on the embodiment, the invention is not limited to the embodiment and can be variously modified without departing from the gist of the invention. Needless to say,

For example, in the above-described embodiment, an example of the electric pump for driving the bellows 16 by the motor 31 has been described. However, it goes without saying that the present invention can be applied to an air-driven pump for driving the bellows by air pressure. No. Note that, as the motor 31, various motors such as a servo motor, a stepping motor, and an ultrasonic motor can be adopted.

In the above description, the case where the invention made by the present inventor is mainly applied to a bellows pump as a field of use has been described. However, the present invention is not limited to this. Applicable.

[0038]

Advantageous effects obtained by typical ones of the inventions disclosed in the present application will be briefly described.
It is as follows.

(1) Since the pump body and the operating valve are integrally formed, there is an effect that the whole fixed-rate discharge pump can be formed compact. As a result, the materials, pipes, joints, etc. constituting the device can be saved, and the number of parts is reduced, so that the maintenance of the device is facilitated and the product reliability is improved. In particular, since the number of connection parts by the joints is reduced, the possibility of occurrence of liquid leakage and the like is reduced.

(2) Since the number of parts is reduced and the number of parts joining surfaces is also reduced, there is an effect that there is little liquid stagnation and dust generation is reduced.

(3) Since the liquid contact portion is configured to be retained in the pump housing, the design and material selection in consideration of corrosion resistance can be suppressed to the minimum, and the cost in terms of material can be reduced. .

(4) Since the operation direction of the diaphragm and the operation direction of the bellows are the same, there is an effect that both seals can be achieved by tightening in the same direction. Therefore, a separate tightening mechanism and operation are not required, and the apparatus structure is simplified, and the number of assembling steps can be reduced.

(5) Since the liquid always flows upward or in the horizontal direction, and there is no point where the flow turns up and down, there is no inflection point where bubbles in the liquid stay, and the effect of good bubble removal is obtained. is there.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an overall configuration of a fixed-rate discharge pump according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a main part of FIG.

FIG. 3 is a partial sectional view taken along line AA of FIG. 2;

FIG. 4 is a cross-sectional view showing the overall configuration of a conventional fixed-rate discharge pump.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Pump part 2 Valve part 3 Drive part 4 Inflow side flow path 5 Discharge side flow path 6 Wear ring 7 Connection plate 8 Liquid storage tank 9 Liquid discharge part 10 Pump room 11 Pump housing 12a Diaphragm mounting part 12b Diaphragm mounting part 13a Diaphragm ( 13b Diaphragm (valve element) 14a Diaphragm fixing ring 14b Diaphragm fixing ring 15a Communication path (first flow path) 15b Communication path (second flow path) 16 Bellows (reciprocating member) 16h Tip 17a Connection path (first) 1 flow path) 17b connection path (second flow path) 18 bellows fixing ring 19a valve chamber 19b valve chamber 20a pilot section 20b pilot section 21a air operated diaphragm valve (first valve device) 21b air operated diaphragm valve (second valve) Valve device) 22 valve housing Group 23a Cylinder hole 23b Cylinder hole 24a Piston 24b Piston 25a Cylinder chamber 25b Cylinder chamber 26a Spring 26b Spring 27a Valve body 27b Valve body 28a Guide washer 28b Guide washer 29b Supply / exhaust passage 30b Exhaust port 31 Motor 32 Chassis 33 Drive Screw nut 35 Ball screw 36 Pulley 37 Pulley 38 Belt 39 Bearing 41 Guide shaft 42 Guide bush 43 Encoder 44 Sensor 50 Metering discharge pump 51 Air operated valve 52 Air operated valve 53 Pump chamber 54 Pump body 55 Inlet side flow path 56 Discharge Side flow path 57 Diaphragm 58 Air cylinder 59 Bellows 60 Piston 61 Spring 62 Connection tube 63 Connection tube

Claims (4)

[Claims] A pump chamber for generating a suction pressure and a discharge pressure by the reciprocating movement of the reciprocating member; and guiding the liquid in the liquid storage tank to the pump chamber. A pump housing provided with a first flow path and a second flow path for guiding the liquid in the pump chamber to a liquid discharge unit; and a valve disposed in the first flow path for opening and closing the first flow path. A first valve device having a body provided in the pump housing and a valve chamber formed in the pump housing; and a valve body disposed in the second flow passage for opening and closing the second flow passage. And a valve housing having a valve chamber formed in the pump housing and a pilot portion for driving each of the valve bodies of the first and second valve devices. And the said, By providing the housing integrally with the pump housing, dispensing pump, characterized in that it disposed the first valve device and the second valve device integrally with the pump chamber. 2. The fixed-rate discharge pump according to claim 1, wherein the first flow path is connected to a center of the first valve device and extends from an upper portion of a valve chamber of the first valve device. Reaching the lower part of the pump chamber, the second flow path is connected from the upper part of the pump chamber to the center of the second valve device and connected to the liquid discharge part from the upper part of the valve chamber of the second valve device, A fixed-rate discharge pump characterized in that liquid sucked into the fixed-rate discharge pump always flows in a horizontal direction or an upward direction. 3. The fixed-rate discharge pump according to claim 1, wherein the reciprocating member is a bellows that operates in the same direction as the operation direction of the valve element. 4. The fixed-rate discharge pump according to claim 1, wherein the valve body is a diaphragm.