JP2001153054A - Liquid discharge pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent inflow of the outside air into a pump compartment in a liquid discharge pump. SOLUTION: A pump body has an elastically deformable pump member 12, an inflow side storing hole 16 and outflow side storing hole 17 opened respectively to a pump compartment 15 are formed in a pump body, the inflow side storing part 16 is in communication with an inlet port 18 and the outflow side storing hole 17 is in communication with an outlet port 19. An inflow side check valve 23 to allow a flow heading for the pump compartment 15 from the inlet port 18 and to block a reverse flow is assembled in from the pump compartment 15 side in the inflow side storing hole 16, and an outflow side check valve 24 to allow a flow heading for the outlet port 19 from the pump compartment 15 and to block a reverse flow is assembled in from the pump compartment 15 side in the outflow side storing hole 17.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid discharge pump adapted to supply a fixed amount of liquid such as a chemical.

[0002]

2. Description of the Related Art In the manufacturing process of electronic parts such as semiconductors, a liquid discharge pump is used to supply a chemical solution, a solution, a cleaning liquid, and the like. As such a liquid discharge pump, such as a bellows and a diaphragm are used. Some have an elastically deformable pump member. As a pump in which the pump member is elastically deformed in the axial direction, for example, a pump disclosed in Japanese Utility Model Laid-Open Publication No. 57-28186 has been developed, and as a pump in which the pump member is elastically deformed in the radial direction, For example, one disclosed in Japanese Patent Laid-Open No. 10-61558 has been developed.

In a liquid discharge pump in which a pump member such as a bellows or a diaphragm is elastically deformed in the axial direction, the pump member expands and contracts by a drive shaft which reciprocates in the axial direction. The shaft is driven by a motor via a lead screw. When the pump member is contracted by the drive shaft, the volume of the pump chamber expands, and the liquid in the container provided outside flows into the pump chamber. When the pump member expands, the volume of the pump chamber contracts and the pump chamber is contracted. Is supplied to a discharge member such as a nozzle.

On the other hand, in a liquid discharge pump using a flexible tube which is elastically deformable in a radial direction as a pump member, a large-diameter bellows portion and a small-diameter bellows portion having different diameters are provided outside the flexible tube. By disposing a bellows having the same and changing the volume inside the bellows, the volume in the flexible tube is expanded and contracted through an incompressible medium filled between the flexible tube and the bellows. To operate the pump.

In such a liquid discharge pump, the liquid in a container provided outside is sucked and a fixed amount of liquid is supplied to a discharge member such as a nozzle provided outside. A check valve or check that allows a flow in one direction and blocks a flow in the opposite direction in each of the inflow-side flow path that communicates with the chamber and the outflow-side flow path that communicates with the pump chamber and the discharge member. In some cases, a valve is provided, and as a check valve, there is a type in which a flow path is closed by its own weight.

[0006]

The check valve is composed of a ball, a valve seat portion in contact with the ball to open and close the flow path, and a plurality of parts such as a guide portion for movably accommodating the ball. The components constituting the stop valve are incorporated in the valve block, and the valve block is attached to the pump body using a screw member. As described above, when the valve block and the pump main body are formed as separate components, the valve block and the pump main body are mounted so as to be in close contact with each other at the contact surface.

When the pump performs a suction operation, a negative pressure is generated in the pump chamber and the inflow-side flow path, so that an O-ring or packing or the like is used to improve the sealing property of the contact surface between the pump body and the valve block. Although the sealing material is arranged on the contact surface, if the sealing property is insufficient, outside air flows into the pump chamber from there, and bubbles enter the pump chamber. Even when the pump performs a discharging operation, outside air may flow in when a negative pressure is generated by the flow of the liquid.

It is not preferable that outside air be mixed into the liquid supplied as described above. In particular, if minute bubbles are mixed in the discharged liquid such as a resist liquid, the production yield of the semiconductor wafer is reduced. In such a case, it is necessary to minimize the inflow of outside air into the pump.

An object of the present invention is to prevent outside air from flowing into a liquid discharge pump.

[0010]

A liquid discharge pump according to the present invention includes a pump body having an elastically deformable pump member, and a pump chamber formed by the pump member, and an opening in the pump body in the pump body. An inflow-side accommodation hole that is formed to communicate with the inlet port, an outflow-side accommodation hole that is formed in the pump body so as to open to the pump chamber, and that communicates with the outlet port. A check valve on the inflow side that is incorporated from the pump chamber side and that allows a flow from the inlet port toward the pump chamber and blocks the flow in the opposite direction, and is incorporated into the outflow side receiving hole from the pump chamber side, And a check valve on the outflow side for allowing a flow from the pump chamber toward the outlet port and preventing a flow in the reverse direction.

In the liquid discharge pump according to the present invention, the pump body is formed by a pump housing having a cylindrical hole, and the pump member is formed by a bellows which expands and contracts when driven by a reciprocating member which reciprocates in an axial direction. Is done. Further, in the liquid discharge pump of the present invention, the pump body is formed by an inflow side block in which the inflow side accommodation hole is formed, an outflow side block in which the outflow side accommodation hole is formed, and a connecting member that connects these. The pump member is a flexible tube having both ends fixed to the inflow-side block and the outflow-side block, and elastically deformed in the radial direction by an external pressure. Each of the check valves has a valve seat that contacts the ball, a guide that movably accommodates the ball, and a fixing member that fixes the valve seat and the guide. The fixing members are fixed to the respective pump main bodies by press-fitting, engaging or screwing into the housing holes.

[0012]

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

FIG. 1 is a sectional view showing a liquid discharge pump according to an embodiment of the present invention. The liquid pump has a pump housing 11 as a pump body, and the pump housing 11 has a cylindrical cylinder. A hole 11a is formed, a bottom wall surface 11b is provided on the front end side, and the rear end side is open.

An elastically deformable pump member 12 is incorporated in the cylinder hole 11a.
Is a bellows type, a reciprocating part 12a at the tip and a ring part 12b fixed to the rear end opening of the pump housing 11.
And a bellows portion 12c between them. The reciprocating portion 12a at the distal end reciprocates in a substantially horizontal direction.
Is a pump chamber 15 whose volume expands and contracts.

A connection plate 13 is fixed to the rear end face of the pump housing 11, and the pump housing 11 is connected to a drive unit (not shown) via the connection plate 13.

A driving shaft 14 as a reciprocating member fixed to the reciprocating portion 12a extends through the connection plate 13 in a substantially horizontal direction to the driving portion. As with the pump described in the publication, a ball screw driven by a motor is screwed to the drive shaft, and the drive shaft 14 reciprocates in the axial direction by driving the motor. Thereby, when the drive shaft 14 is moved forward and the bellows portion 12c expands, the pump chamber 15
The volume of the pump chamber 15 expands when the volume of the pump chamber 15 contracts and the drive shaft 14 is moved backward to contract the bellows portion 12c. However, the reciprocating motion of the drive shaft 14 may be performed by another driving means such as a pneumatic cylinder.

An inflow-side accommodation hole 16 is formed in the lower part of the pump housing 11 so as to open to the pump chamber 15, and an outflow-side accommodation hole 17 is formed in the upper part to open to the pump chamber 15. The holes 16 and 17 face each other.

An inlet port 1 is provided at the bottom of the inflow side receiving hole 16.
8 communicate with the outlet port 1 at the bottom of the outlet side receiving hole 17.
9, the inlet port 18 is connected to a tank or container T containing the liquid by an inflow-side channel 21, and the outlet port 19 is a nozzle for discharging the liquid by an outflow-side channel 22. Is connected to the liquid ejection member N.

An inlet port 18 is provided in the inflow side receiving hole 16.
An inflow check or check valve 23 for allowing the flow from the pump chamber 15 toward the pump chamber 15 and preventing the flow in the opposite direction is incorporated, and the flow from the pump chamber 15 to the outlet port is allowed in the outlet side receiving hole 17. An outflow check valve 24 for preventing reverse flow is incorporated.

Each of the check valves 23 and 24 has a valve seat 25 formed with a communication hole communicating with a port, a ball 26 for opening and closing the communication hole of the valve seat 25, and a ball 26 for opening and closing. And a fixing member 28 for fixing these to the receiving holes 16 and 17.

FIG. 2A is an exploded perspective view showing members constituting the check valve 23, and FIG. 2B is an exploded perspective view showing members constituting the check valve 24. Each component has a different positional relationship between the two check valves 23 and 24, but the same components are used.

That is, each of the valve seat portions 25 is provided with annular engaging projections 31 and 32 on both upper and lower surfaces, and the guide portions 27 are provided.
As shown in FIG. 1, an annular engagement groove 33 is provided on one end surface, an annular engagement protrusion 34 is provided on the other end surface, and an annular engagement groove 35 is provided on the fixing member 28. 2 (B). Each accommodation hole 16,1
As shown in FIG. 1, an annular engagement groove 36 is provided on the bottom surface of the fixing member 7, and an engagement groove 38 with which the fixing portion 37 of the fixing member 28 engages is provided on the inner peripheral surface. Therefore, in order to incorporate the check valve 23 into the inflow-side receiving hole 16, first, before the pump member 12 is incorporated into the pump housing 11, the valve seat 25 is first engaged with the engagement projection 31 through the engagement groove 36.
And the receiving hole 16 from the pump chamber 15 side.
And the ball 26, the guide portion 27
After the fixing, the fixing member 28 is connected to the pump housing 1.
Fix to 1.

Similarly, in order to incorporate the check valve 24 into the outflow-side accommodation hole 17, first, the guide portion 27 is incorporated into the accommodation hole 17 from the pump chamber 15 side to accommodate the engagement projection 34 of the guide portion 27. The ball 2 is engaged with the engagement groove of the hole 17 and the ball 2
After assembling with 6 and the valve seat 25, the fixing member 28 is fixed to the pump housing 11.

The pump housing 11, the pump member 12, and the respective check valves 23 and 24 are made of a fluororesin in consideration of the corrosiveness of these liquids because the liquid supplied by the pump is a chemical such as a resist liquid. Of polytetrafluoroethylene (PTFE). However, depending on the type of liquid to be supplied, another resin or a metal may be used.

Each of the check valves 23 and 24 is provided with pump holes 16 and 17 for accommodating the check valves 23 and 24, respectively, without attaching a valve block for accommodating the check valves to the pump housing. Housing 11
Since the airtightness of the check valve is increased, the airtightness of the check valve is improved, and the outside air can be prevented from flowing into the pump chamber 15 from the check valve portion during the pump operation.

FIG. 3 is a sectional view showing a liquid discharge pump according to another embodiment of the present invention. In FIG. 3, the same reference numerals are used for members common to the members constituting the above-described embodiment. Is attached.

This liquid discharge pump has a lower inflow side block 41a and an upper outflow side block 41b, and a flexible tube 42 as a pump member is provided in the inflow side block 41a and the outflow side block 41b. Mounted at both ends. This liquid discharge pump is disclosed in
As in the case described in JP-A-10-62558, the pump has a flexible tube 42 as a pump member, and the inside of the flexible tube 42 is a pump chamber 15.

An inlet port 18 is formed in the lower inflow side block 41a, and an outlet port 19 is formed in the upper outflow side block 41b. The inflow side block 41a and the outflow side block 41b are connected by a connecting member 43. A pump housing as the pump body 41 is formed by these and the connecting member 43.

A bellows 44 that is elastically deformable in the axial direction is disposed outside the flexible tube 42. The bellows 44 includes a lower fixed disk 45 fixed to the inflow side block 41a, a central operating disk 46,
It has a large-diameter bellows portion 47 between them, and further has a fixed disk 48 at the other end fixed to the outflow-side block 41b and a small-diameter bellows portion 49 between the fixed disk 48 and the working disk 46. are doing.

The space between the flexible tube 42 and the bellows 44 is a driving chamber 51 in which an incompressible medium 52 such as a liquid is sealed. Therefore, the bellows 44 is moved to the working disk 4 in the central portion thereof.
When it is elastically deformed in the axial direction at 6, the overall length of the bellows 44 does not change, and the volume inside the large bellows portion 47 and the small bellows portion 49 changes. This allows
The flexible tube 42 is pressurized in the radial direction, that is, in the lateral direction via the incompressible medium 52 to expand and contract, and the flexible tube 42 performs a pump operation.

The flexible tube 42, the bellows 44 and the respective pump main body 41 are made of P
Manufactured by TFE.

A reciprocating member 53 is attached to the working disk 46, and a ball screw is screwed to the reciprocating member 53 in the same manner as described in the above-mentioned publication. Thereby, the pump operation is performed by driving the ball screw by the motor to reciprocate the working disk 46.

An inflow side receiving hole 16 is formed in the lower inflow side block 41a, and an outflow side receiving hole 17 is formed in the upper outflow side block 41b.
17 has a check valve 2 shown in FIG.
3, 24 are incorporated. Therefore, when assembling this liquid discharge pump, each of the receiving holes 16,
After the members constituting the check valves 23 and 24 are assembled into the block 17, the flexible tubes 42 are fitted at both ends between the inflow side blocks 41a and the outflow side blocks 41b, and the bellows 44 are connected. Will be attached.

As described above, each check valve 23, 24
A valve block for accommodating each of them is provided with an inflow side block 41a and an outflow side block 4
1b, the check valves 23, 2
The housing holes 16 and 17 for housing the pump housing 11 are
Since the check valve is formed integrally with the inlet block and the outlet block, the airtightness of the check valve is improved, and the outside air can be prevented from flowing into the pump chamber 15 from the check valve portion during the pump operation.

The present invention is not limited to the above-described embodiment, and it goes without saying that various changes can be made without departing from the scope of the invention.

For example, the check valves 23 and 24 described above
It has a fixing member 28 and a fixing portion 37 provided on the fixing member 28.
Is engaged with an engagement groove 38 provided on the pump body side to fix other members constituting the check valve in the respective accommodation holes 16 and 17. Female threads may be formed in 41a and 41b, and the fastening portion 37 may be screw-coupled with the fastening portion 37 as a male screw, or the fixing member 28 may be press-fitted and fixed.

[0037]

According to the present invention, in the liquid discharge pump having the check valves on the inflow side and the outflow side, the respective check valves are incorporated into the receiving holes formed in the member constituting the pump body. Therefore, there is no contact surface extending to the outside at the check valve portion, and the airtightness of the check valve portion is improved. This prevents outside air from flowing into the pump and prevents bubbles from entering the liquid in the pump.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a liquid discharge pump according to an embodiment of the present invention.

FIG. 2A is an exploded perspective view showing members constituting a check valve on the inflow side, and FIG. 2B is an exploded perspective view showing members constituting a check valve on the outflow side. is there.

FIG. 3 is a sectional view showing a liquid discharge pump according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Pump housing 11a Cylinder hole 11b Bottom wall surface 12 Pump member 12a Reciprocating part 12b Ring part 12c Bellows part 14 Drive shaft 15 Pump chamber 16 Inflow side accommodation hole 17 Outflow side accommodation hole 18 Inlet port 19 Outlet port 21 Inlet side flow path 22 Outflow side flow path 23, 24 Check valve 25 Valve seat 26 Ball 27 Guide part 28 Fixing member 41 Pump housing 41a Inflow side block 41b Outflow side block 42 Flexible tube 43 Connecting member 44 Bellows 45 Fixed disk 46 Working disk 47 Large-diameter bellows 48 Fixed disk 49 Small-diameter bellows 52 Incompressible medium

Claims (5)

[Claims] A pump body having an elastically deformable pump member, and a pump chamber formed by the pump member; and a pump body formed in the pump body so as to open to the pump chamber;
An inflow-side receiving hole communicating with the inlet port, and formed in the pump body so as to open to the pump chamber;
An outlet-side receiving hole communicating with the outlet port; and an inlet-side reverse which is incorporated into the inlet-side receiving hole from the pump chamber side and allows a flow from the inlet port toward the pump chamber and prevents a flow in the opposite direction. A stop valve, which is incorporated in the outflow-side housing hole from the pump chamber side, and has an outflow-side check valve that allows a flow from the pump chamber toward the outlet port and blocks a flow in the reverse direction. Liquid discharge pump. 2. The liquid discharge pump according to claim 1, wherein the pump body is formed by a pump housing having a cylindrical hole, and the pump member is driven by a reciprocating member that reciprocates in an axial direction to expand and contract. A liquid discharge pump characterized by being formed by a bellows. 3. The liquid discharge pump according to claim 1, wherein the pump body is connected to an inflow-side block having the inflow-side accommodation hole and an outflow-side block having the outflow-side accommodation hole. Formed by the member,
A liquid discharge pump, wherein the pump member is a flexible tube having both ends fixed to the inflow-side block and the outflow-side block and elastically deformed in a radial direction by a pressure from the outside. 4. The liquid discharge pump according to claim 1, wherein each of the check valves is a valve seat that contacts a ball and a guide that movably accommodates the ball. And a fixing member for fixing the valve seat portion and the guide portion. 5. The liquid discharge pump according to claim 4, wherein the fixing member is fixed to the respective pump main bodies by press-fitting, engaging, or screwing into the housing holes.