CN117651807A

CN117651807A - Liquid supply device

Info

Publication number: CN117651807A
Application number: CN202280048246.9A
Authority: CN
Inventors: 矢岛丈夫; 村冈裕之
Original assignee: Koganei Corp
Current assignee: Koganei Corp
Priority date: 2021-07-30
Filing date: 2022-07-11
Publication date: 2024-03-05
Also published as: WO2023008169A1; KR20240036558A; JP2023020185A; JP2023134856A; JP7369321B2; JP2023133587A; JP7357179B2

Abstract

A liquid supply device for expanding a tubular film (15) as a first flexible member to inject liquid into a pump chamber (16), contracting the tubular film (15) to discharge the liquid in the pump chamber (16) to the outside, comprising: a medium housing case (28) provided with a bellows (31) as a second flexible member that separates a medium housing chamber (32) and an air chamber (33) that communicate with the pump housing chamber (17); a drive mechanism (27) provided with a lever (44 a); an electric motor (46) as a driving means for reciprocating the rod (44 a) in the axial direction; and a pressure adjustment mechanism (60) that reduces the pressure of the air chamber (33) when the bellows (31) is contracted and the tubular film (15) is expanded via the liquid medium (M).

Description

Liquid supply device

Technical Field

The present invention relates to a liquid supply device for supplying a liquid to an object to be coated.

Background

In the field of semiconductor integrated circuit devices, liquid crystal panels, and the like, liquid supply devices are used to supply a liquid such as a photoresist liquid to an object to be coated, and in the case of manufacturing a secondary battery using an electrolyte, the liquid supply devices are used to supply the electrolyte to the inside of a battery container.

As described in patent document 1, such a liquid supply device includes: a pump housing in which a tubular film is incorporated as a flexible member that is elastically deformable in the radial direction; and a bellows housing in which a bellows is incorporated as a flexible member that is stretchable in the axial direction. The primary side port of the pump chamber in the tubular film is connected to the liquid tank, and the secondary side port of the pump chamber is connected to the liquid discharge portion. The pump housing chamber in the pump housing communicates with the medium housing chamber in the bellows housing, is filled with a liquid medium composed of a non-compressible liquid, expands and contracts the pump chamber via the liquid medium by the bellows, and the liquid in the liquid tank is discharged from the liquid discharge portion.

Prior art literature

Patent literature

Patent document 1: japanese patent application laid-open No. 2012-162269

Disclosure of Invention

Technical problem to be solved by the invention

As described in patent document 1, in a liquid supply device that includes a tubular membrane incorporated in a pump housing and a bellows incorporated in a bellows housing, and that pumps the tubular membrane through a liquid medium by a telescopic operation of the bellows, the bellows contracts when liquid is sucked into a pump chamber in the tube. Thereby, the liquid medium in the pump housing chamber of the pump housing is sucked into the medium housing chamber in the bellows case, and the tubular film is radially expanded. On the other hand, the bellows is extended when the liquid sucked into the pump chamber is discharged to the liquid discharge portion. Thereby, the liquid medium in the medium housing chamber in the bellows housing is supplied into the pump housing chamber of the pump housing, and the tubular film is contracted. In this way, in the liquid supply device including the two flexible members, the pump operation is performed by the two flexible members.

When the bellows is extended to contract the tubular film via the liquid medium, a positive pressure is applied to the outer surface of the bellows portion by the liquid medium when the liquid is discharged from the pump chamber. On the other hand, the volume of the inside of the bellows increases, and the inner surface of the bellows becomes a negative pressure state. If the pressure difference between the positive pressure on the outer surface and the negative pressure on the inner surface of the bellows exceeds a predetermined value, the bellows deforms in a direction in which the outer diameter of the bellows decreases. On the other hand, when the bellows is contracted to expand the tubular film through the liquid medium, the outer surface of the bellows is brought into a negative pressure state at the time of injecting the liquid into the pump chamber. On the other hand, the volume of the inside of the bellows decreases, thereby applying positive pressure to the inner surface of the bellows. If the pressure difference between the negative pressure on the outer surface and the positive pressure on the inner surface of the bellows exceeds a predetermined value, the bellows deforms in a direction in which the outer diameter of the bellows increases.

Therefore, it is considered that when the tubular film is contracted to discharge the liquid from the pump chamber to the outside, the discharge amount corresponding to the expansion stroke of the bellows is different from the set value, and when the tubular film is expanded to inject the liquid into the pump chamber, the suction amount corresponding to the contraction stroke of the bellows is different from the set value. In this way, if the effective diameters in the radial direction of the bellows portion are different between when the bellows is extended and when the bellows is contracted, the liquid cannot be ejected from the pump chamber toward the liquid ejection port with high accuracy, and the ejection accuracy of the liquid is lowered.

When the bellows is contracted to inject the liquid into the pump chamber, if the outer surface of the bellows is at a lower pressure than the inner surface, there is a concern that air in the air chamber inside the bellows may permeate the bellows of the resin material and be mixed into the liquid medium. If air is mixed into the liquid medium, the ejection accuracy of the liquid from the pump chamber is lowered. Such a decrease in ejection accuracy may occur in a liquid supply device that performs a pumping operation using a bellows or a diaphragm as a flexible member that separates a pump chamber from an air chamber.

The invention aims to inhibit the pressure difference between the inside and the outside of a flexible member from increasing and improve the liquid ejection accuracy in a liquid supply device which performs pump operation through the flexible member.

Technical scheme for solving technical problems

A liquid supply device according to one aspect of the present invention includes a first flexible member disposed in a pump housing and separating a pump chamber and a pump housing chamber, the liquid supply device including: a medium housing case having a second flexible member that partitions a medium housing chamber and an air chamber that communicate with the pump housing chamber; a liquid medium filled in the pump housing chamber and the medium housing chamber; a driving member that reciprocates a lever attached to the second flexible member in a discharge direction in which the liquid medium is supplied from the medium accommodating chamber to the pump accommodating chamber and in an injection direction in which the liquid medium is returned from the pump accommodating chamber to the medium accommodating chamber; and a pressure adjustment mechanism that reduces the pressure of the air chamber when the rod is driven in the injection direction and the volume of the air chamber is reduced.

Another aspect of the present invention provides a liquid supply device including a flexible member disposed in a pump housing and separating a pump chamber and an air chamber, the liquid supply device including: a driving member that reciprocates a rod attached to the flexible member in a discharge direction in which the liquid in the pump chamber is discharged to the outside and in an injection direction in which the liquid is injected into the pump chamber; and a pressure adjustment mechanism that reduces the pressure of the air chamber when the rod is moved in the injection direction and the volume of the air chamber is reduced.

Effects of the invention

In a liquid supply device that performs a pumping operation by first and second flexible members, when a volume of a pump chamber is increased by the first flexible member to inject liquid into the pump chamber, a pressure of a medium accommodating chamber in contact with an outer surface of the second flexible member is reduced. On the other hand, the pressure in the air chamber that is brought into contact with the inner surface of the second flexible member by the pressure adjustment mechanism decreases in accordance with the pressure in the medium housing chamber or the contraction of the second flexible member. Accordingly, the pressure difference between the medium accommodating chamber and the air chamber is reduced, so that the air in the air chamber can be prevented from being mixed into the medium driving chamber through the second flexible member, and the excessive deformation in the direction in which the volume of the air chamber is increased can be prevented, and the pump characteristic can be maintained with high accuracy over a long period of time.

In a liquid supply device that performs a pumping operation by a flexible member that separates a pump chamber and an air chamber, when the volume of the pump chamber is increased to pump liquid into the pump chamber, the pressure of the pump chamber is reduced with respect to the air chamber, but the pressure of the air chamber is reduced in accordance with the pump chamber by a pressure adjustment mechanism. In this way, since the pressure difference between the pump chamber and the air chamber is small, the air in the air chamber can be prevented from penetrating the flexible member and mixing into the medium driving chamber, and excessive deformation in the direction in which the volume of the air chamber increases can be prevented, so that the pump characteristics can be maintained with high accuracy over a long period of time.

Drawings

Fig. 1 is a sectional view showing a liquid supply device according to an embodiment, and shows a state in which a tubular film as a first flexible member is radially expanded to inject liquid into a pump chamber.

Fig. 2 is a sectional view showing the liquid supply device in a state in which the tubular film is contracted in the radial direction and liquid is discharged from the pump chamber to the outside.

Fig. 3 is an enlarged sectional view showing the pressure regulating piston shown in fig. 1 and 2.

Fig. 4 is a cross-sectional view showing a liquid supply device according to another embodiment.

Fig. 5 is an air pressure circuit diagram of the air pressure control device shown in fig. 4.

Fig. 6 is a cross-sectional view showing a liquid supply device according to another embodiment.

Fig. 7 is a sectional view showing a liquid supply device according to still another embodiment.

Fig. 8 is an air pressure circuit diagram of the pressure adjusting mechanism in the liquid supply device shown in fig. 6 and 7.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The liquid supply device 10a shown in fig. 1 to 3 includes a pump 11 and a pump driving unit 12. The pump 11 has a pump housing 14 formed with a housing hole 13 penetrating in the longitudinal direction, and a tubular film 15 as a first flexible member is disposed in the pump housing 14. The tubular film 15 is a flexible pump member formed of a resin material such as a fluororesin and elastically deformed in the radial direction. The tubular membrane 15 is partitioned into an inner pump chamber 16 and an outer pump housing chamber 17. The inflow-side joint 18 is provided at one end portion of the pump housing 14, and the outflow-side joint 19 is provided at the other end portion of the pump housing 14.

When the inflow-side joint 18 is connected to the liquid tank 22 via the inflow-side pipe 21 and the outflow-side joint 19 is connected to the liquid discharge portion 24 via the outflow-side pipe 23, the liquid L in the liquid tank 22 can be discharged from the liquid discharge portion 24. The liquid discharged from the liquid discharge unit 24 is supplied to an object to be coated, not shown. When the tubular film 15 is radially expanded to increase the volume of the pump chamber 16, the liquid L in the liquid tank 22 is injected into the pump chamber 16, and when the tubular film 15 is radially contracted to decrease the volume of the pump chamber 16, the liquid L in the pump chamber 16 is discharged to the outside toward the liquid discharge portion 24.

The check valve 25 is provided in the inflow side pipe 21. The check valve 25 allows the liquid L in the liquid tank 22 to flow toward the pump chamber 16 through the inflow side pipe 21 when the volume of the pump chamber 16 is increased, and prevents the liquid in the inflow side pipe 21 from flowing backward toward the liquid tank 22 when the volume of the pump chamber 16 is reduced. The check valve 26 is provided in the outflow pipe 23. The check valve 26 allows the liquid L in the pump chamber 16 to flow toward the liquid discharge portion 24 through the outflow side pipe 23 when the volume of the pump chamber 16 is reduced, and prevents the liquid L in the outflow side pipe 23 from flowing backward toward the pump chamber 16 when the volume of the pump chamber 16 is increased. Instead of the check valves 25 and 26, electromagnetic-operated and air-pressure-operated opening/closing valves may be provided in the inflow piping 21 and the outflow piping 23, and the operation of the opening/closing valves may be controlled in accordance with the pump operation of the tubular membrane 15 for expansion and contraction.

The pump drive unit 12 has a medium housing case 28. The bellows 31 as the second flexible member is mounted to the medium housing case 28, and the bellows 31 has a bellows portion 31a, an end plate portion 31b provided at one end portion of the bellows 31, and an annular base end portion 31c provided at the other end portion, and is integrally formed of a resin material such as a fluororesin. The bellows 31a is elastically deformable in the axial direction.

The bellows 31 separates an outer medium housing chamber 32 and an inner air chamber 33. The bellows 31 is a flexible partition member that is expandable and contractible in the axial direction as a whole. The medium housing chamber 32 communicates with the pump housing chamber 17 through a communication hole 34 formed in the pump housing 14 and the medium housing case 28. The pump housing chamber 17 and the medium housing chamber 32 are filled with a liquid medium M made of a liquid, and the liquid medium M is movable between the pump housing chamber 17 and the medium housing chamber 32 via the communication hole 34. In addition, the pump 11 may be separated from the pump driving unit 12 without being attached thereto. In this case, a medium pipe for guiding the liquid medium M is connected between the pump 11 and the medium housing case 28.

A cylinder 36 having an end plate 35 is attached to the medium housing case 28, and the base end 31c of the bellows 31 is sandwiched between the end plate 35 and the medium housing case 28. The cylinder 36 is provided with a drive mechanism 27 including a rod 44 and an electric motor 46, and the rod 44 is reciprocated by the drive mechanism 27. A connecting plate 37 is attached to the open end of the cylinder 36, and a support plate 39 to which a bearing 38 is attached to the connecting plate 37 via a side plate 41. A rod 44 is disposed so as to pass through a through hole 42 formed in the end plate 35 and a through hole 43 formed in the connecting plate 37 and to be reciprocally movable in the axial direction, and a male screw portion 45 provided at the tip end of the rod 44 is screwed to the end plate portion 31b of the bellows 31.

In order to reciprocate the rod 44 in the axial direction, the electric motor 46 is attached to the support plate 39 via a pedestal 47, and a main shaft 48 of the electric motor 46 is coupled to a feed screw shaft 51 via a coupling 49. The base end of the feed screw shaft 51 is rotatably supported by the bearing 38, and the tip end of the feed screw shaft 51 protrudes into a receiving hole 52 formed in the rod 44. The inner diameter of the housing hole 52 is larger than the outer diameter of the feed screw shaft 51. The feed screw shaft 51 is a ball screw, and a nut 53 is screwed to the feed screw shaft 51 via a ball. The nut 53 is attached to a bracket 54, and the bracket 54 is fixed to the base end portion of the rod 44. The guide rod 55 axially penetrates the bracket 54, and one end portion of the guide rod 55 is fixed to the connecting plate 37 and the other end portion is fixed to the support plate 39. The holder 54 is guided by the guide rod 55 to move in the axial direction without rotating. In fig. 1 and 2, only one guide rod 55 is shown, but a plurality of guide rods 55 are provided in the driving mechanism 27.

When the electric motor 46 as a driving means is driven, the feed screw shaft 51 moves the rod 44 in the axial direction via the nut 53 and the bracket 54. Thereby, the bellows 31 expands and contracts in the axial direction. Fig. 1 shows a state in which the tubular film 15 is radially expanded, and in this state, when the feed screw shaft 51 is rotated in one direction by the electric motor 46, the rod 44 moves in a direction in which the bellows 31 is elongated, and the bellows 31 is elongated. When the bellows 31 is extended, as shown in fig. 2, the end plate portion 31b reduces the volume of the medium accommodating chamber 32, and the liquid medium M in the medium accommodating chamber 32 flows into the pump accommodating chamber 17. When the liquid medium M flows into the pump housing chamber 17, the tubular film 15 radially contracts, and the liquid L that has been sucked into the pump chamber 16 from the liquid tank 22 is ejected toward the external liquid ejecting portion 24. At this time, the liquid in the pump chamber 16 is prevented from flowing backward to the inflow side pipe 21 by the check valve 25.

On the other hand, as shown in fig. 2, when the feed screw shaft 51 is rotated in the opposite direction to the above direction by the electric motor 46 in a state where the tubular film 15 is contracted in the radial direction, the rod 44 moves in a direction to contract the bellows 31 in the axial direction, and the bellows 31 is contracted. When the bellows 31 is contracted, as shown in fig. 1, the volume of the medium accommodating chamber 32 increases, and the liquid medium M in the pump accommodating chamber 17 flows into the medium accommodating chamber 32. When the liquid medium M in the pump housing chamber 17 flows into the medium housing chamber 32, the tubular film 15 expands in the radial direction, and the liquid L is sucked from the liquid tank 22 into the pump chamber 16. At this time, the liquid in the outflow pipe 23 is prevented from flowing backward toward the pump chamber 16 by the check valve 26.

In this way, the lever 44 is reciprocated by the electric motor 46 as a driving means in the discharge direction of supplying the liquid medium M from the medium accommodating chamber 32 to the pump accommodating chamber 17 and in the suction direction of returning the liquid medium M from the pump accommodating chamber 17 to the medium accommodating chamber 32. When the tubular film 15 is radially expanded, the liquid L in the liquid tank 22 is sucked into the pump chamber 16, and when the tubular film 15 is radially contracted, the liquid L in the pump chamber 16 is discharged to the outside.

When the bellows 31 is contracted in the axial direction and the tubular film 15 is expanded in the radial direction via the liquid medium M, the outer surface of the bellows 31a becomes a lower pressure than the inner surface when the liquid L is sucked from the liquid tank 22 into the pump chamber 16. Therefore, when the bellows 31 is contracted in the axial direction, the bellows 31 may be slightly deformed in the radial direction so that the average effective diameter of the bellows portion 31a becomes larger. If the average effective diameter of the bellows portion 31a is changed in a direction in which it becomes larger, a predetermined amount of liquid cannot be injected into the pump chamber 16, and the accuracy of liquid ejection from the pump chamber 16 may be lowered. If the outer surface of the bellows portion 31a is at a lower pressure than the inner surface, the gas in the air chamber 33 may permeate the resin bellows 31 and be mixed into the liquid medium M. If outside air is mixed into the liquid medium M, the accuracy of liquid ejection from the pump chamber 16 is lowered.

On the other hand, by expanding the bellows 31 in the axial direction and contracting the tubular film 15 via the liquid medium M, when the liquid L is discharged from the pump chamber 16 into the outflow-side piping 23, the pressure of the liquid medium M is applied to the outer surface of the bellows portion 31a of the bellows 31. Therefore, when the bellows 31 is elongated in the axial direction, it is considered that the bellows 31a may be slightly deformed in the radial direction so as to reduce the average effective diameter of the bellows. If the average effective diameter of the bellows portion 31a is reduced, the accuracy of liquid ejection from the pump chamber 16 may be lowered. Even if the pressure of the outer surface of the bellows 31a is higher than that of the inner surface, the liquid medium M composed of the liquid does not leak into the air chamber 33 through the bellows 31.

The pressure regulating piston 56 is disposed in the cylinder 36, and the pressure regulating piston 56 is attached to the rod 44 and reciprocates in synchronization with the bellows 31. A pressure adjusting chamber 57 partitioned by the end plate 35 and the pressure adjusting piston 56 is formed inside the cylinder 36. The communication hole 58 is formed in the end plate 35 of the cylinder 36, and the air chamber 33 communicates with the pressure adjustment chamber 57 through the communication hole 58. The outer diameter of the pressure regulating piston 56 is set to a diameter larger than the average effective diameter of the bellows portion 31a of the bellows 31. The pressure regulating piston 56 constitutes the pressure regulating mechanism 60, and when the bellows 31 is contracted in the axial direction by the rod 44 and the tubular film 15 is expanded in the radial direction via the liquid medium M, the diameter of the pressure regulating piston 56 is larger than the average effective diameter of the bellows portion 31a, and therefore, the air in the air chamber 33 is sucked into the pressure regulating chamber 57.

Thereby, the pressure in the air chamber 33 decreases with the movement of the lever 44. As a result, the pressure difference between the air chamber 33 and the medium housing chamber 32 becomes small, so that the air in the air chamber 33 can be prevented from penetrating the bellows 31 and mixing into the medium housing chamber 32, and the pump characteristic can be maintained with high accuracy over a long period of time. When the bellows 31 is contracted, the bellows portion 31a is prevented from being deformed in a direction in which the average effective diameter increases in the radial direction, and the amount of the liquid L injected into the pump chamber 16 can be set with high accuracy.

When the bellows 31 is extended by the rod 44 and the tubular film 15 is contracted in the radial direction via the liquid medium M by the pressure adjusting mechanism 60 including the pressure adjusting piston 56, air in the pressure adjusting chamber 57 having a larger diameter than the air chamber 33 is supplied into the air chamber 33, and the pressure in the air chamber 33 increases with the movement of the rod 44.

Accordingly, when the bellows 31 is extended, deformation of the bellows portion 31a in the direction in which the average effective diameter becomes smaller is suppressed, and the discharge amount of the liquid L discharged from the pump chamber 16 to the outside can be set with high accuracy.

By changing the rotation direction of the electric motor 46 in the forward rotation direction and the reverse rotation direction, the tubular film 15 can perform a pumping operation. The rotational direction and rotational speed of the electric motor 46 are controlled by a drive signal from a control unit, not shown. The control unit stores data of the number of rotations in both the forward and reverse directions in advance in the memory in accordance with the expansion/contraction stroke of the bellows 31.

Fig. 3 is an enlarged sectional view showing the pressure regulating piston 56 shown in fig. 1 and 2. The pressure regulating piston 56 is provided with a negative pressure release valve 61 and a positive pressure release valve 62.

The negative pressure relief valve 61 includes a cylindrical body 64a formed with an outside air introduction hole 63a, a valve seat 65a provided on the cylindrical body 64a, and a valve shaft 68a provided with a valve member 66a and supported by a valve shaft guide 67a, and a fixing sleeve 69a is mounted between the valve seat 65a and the valve shaft guide 67 a. A spring member 70a that applies a spring force to the valve member 66a in a direction to close the outside air introduction hole 63a is fitted between the valve member 66a and the valve shaft guide 67 a. When the pressure of the pressure adjusting chamber 57 is lower than the allowable negative pressure determined according to the spring constant or the like of the spring member 70a, in other words, when the negative pressure value becomes large, the valve member 66a is separated from the valve seat 65a to open the outside air introduction hole 63a. The pressure adjustment chamber 57 communicates with the outside of the drive mechanism 27, and outside air is supplied to the pressure adjustment chamber 57. As a result, when the bellows 31 is contracted in the axial direction and the tubular film 15 is expanded in the radial direction, the differential pressure between the pressure in the air chamber 33 and the medium accommodating chamber 32 can be suppressed to an excessive magnitude that deforms the bellows portion 31a of the bellows 31.

The positive pressure relief valve 62 includes a cylindrical body 64b in which the air discharge hole 63b is formed, a valve seat 65b provided in the cylindrical body 64b, and a valve shaft 68b provided with a valve member 66b and supported by a valve shaft guide 67b, and a fixing sleeve 69b is mounted between the valve seat 65b and the valve shaft guide 67 b. A spring member 70b that applies a spring force to the valve member 66b in a direction to close the air discharge hole 63b is fitted between the valve member 66b and the valve shaft guide 67 b. When the pressure in the pressure adjustment chamber 57 is higher than the allowable positive pressure determined by the spring constant of the spring member 70b or the like, the valve member 66b is separated from the valve seat 65b, and the air in the pressure adjustment chamber 57 is discharged to the outside of the pump driving unit 12 through the air discharge hole 63 b. As a result, when the bellows 31 is axially extended and the tubular film 15 is radially contracted, the differential pressure between the pressure in the air chamber 33 and the pressure in the medium accommodating chamber 32 is suppressed to an excessive positive pressure differential pressure that deforms the bellows portion 31a of the bellows 31.

As described above, the negative pressure relief valve 61 and the positive pressure relief valve 62 are common in the constituent members, while the valve shafts 68a and 68b are opposite to each other. In addition, if the rod 44 and the pressure regulating piston 56 can be moved synchronously, the rod 44 and the pressure regulating piston 56 may be moved by different electric motors. When the bellows 31 is axially expanded and contracted, if the pressure in the air chamber 33 and the differential pressure in the medium accommodating chamber 32 are not excessively large enough to deform the bellows portion 31a of the bellows 31, the pressure-adjusting piston 56 may not be provided with the negative pressure relief valve 61 and the positive pressure relief valve 62.

Fig. 4 is a cross-sectional view showing a liquid supply device 10b according to another embodiment, and in fig. 4, members common to those constituting the liquid supply device 10a are denoted by the same reference numerals, and redundant description thereof is omitted.

As in the case shown in fig. 1 and 2, the pump 11 includes a pump housing 14 having a housing hole 13 formed therein, and a tubular film 15 made of a resin material such as a fluororesin and elastically deformable in the radial direction is disposed as a first flexible member in the pump housing 14. The inflow-side joint 18 is provided at one end portion of the pump housing 14, and the outflow-side joint 19 is provided at the other end portion of the pump housing 14. In fig. 4, the inflow pipe 21 connected to the inflow joint 18, the outflow pipe 23 connected to the outflow joint 19, and the like are omitted.

The pump driving unit 12 has a medium housing case 28 attached to the pump 11, and a bellows 31 is mounted as a second flexible member in the medium housing case 28. The bellows 31 has a bellows portion 31a, an end plate portion 31b provided at one end portion of the bellows 31, and an annular base end portion 31c provided at the other end portion, and is integrally formed of a resin material that is stretchable in the axial direction, such as a fluororesin.

The bellows 31 separates an outer medium housing chamber 32 and an inner air chamber 33. The medium housing chamber 32 communicates with the pump housing chamber 17 through a communication hole 34 formed in the pump housing 14 and the medium housing case 28. The pump housing chamber 17 and the medium housing chamber 32 are filled with a liquid medium M composed of a liquid.

The end plate 71 is fixed to the opening-side end portion of the medium housing case 28, and the base end portion 31c of the bellows 31 is sandwiched between the end plate 71 and the medium housing case 28. A rod 44 is mounted so as to pass through a through hole 72 formed in the end plate 71 and to be movable in an axial direction, and a male screw portion 45 provided at a distal end of the rod 44 is screwed to the end plate portion 31b. The support plate 73 is coupled to the end plate 71 by a coupling rod 74, and the feed screw shaft 51 is rotatably supported by the support plate 73 via a bearing 75. The nut 53 screwed to the feed screw shaft 51 via the balls is fixed to the bracket 54, and the bracket 54 is fixed to the rod 44.

One end of the guide rod 55 is fixed to the end plate 71, and the other end of the guide rod 55 is fixed to the support plate 73. The guide rod 55 axially penetrates a bracket 54 fixed to the rod 44, and the bracket 54 is guided by the guide rod 55 by rotation of the feed screw shaft 51 and moves in the axial direction without rotation.

The electric motor 46 for rotating the feed screw shaft 51 is mounted on a base plate 76 mounted on a support plate 73, and a belt 79 is suspended between a pulley 77 fixed to the driving side of the main shaft 48 of the electric motor 46 and a pulley 78 fixed to the driven side of the lever 44. The drive mechanism 27 having the belt 79 is housed in a housing 81 mounted to the pump 11.

The rod 44 and the through hole 72 of the end plate 71 are sealed by a sealing member 82, and the air chamber 33 is a sealed space. When the inside of the medium accommodating chamber 32 is negative, the negative pressure is supplied to the air chamber 33 by the pressure adjusting mechanism 60 in accordance with the pressure in the medium accommodating chamber 32. The pressure adjustment mechanism 60 is formed by an air pressure control mechanism 83, and fig. 5 shows an air pressure circuit diagram of an air pressure control device constituting the air pressure control mechanism 83.

As shown in fig. 4 and 5, the air pressure control mechanism 83 includes a vacuum ejector 84. The vacuum ejector 84 is known to include an air supply port 85, a diffuser 86 that ejects compressed air supplied from the air supply port 85, and an air discharge port 87, and the suction port 88 is provided in the vacuum ejector 84 in communication with the diffuser 86. When compressed air is supplied from the air supply port 85 toward the diffuser 86, the suction port 88 is set to negative pressure by the air passing through the diffuser 86 toward the air discharge port 87. The suction port 88 communicates with a suction hole 89 formed in the end plate 71 through a flow path 90.

The pressure of the compressed air supplied to the air supply port 85 is regulated by the regulator 91. The regulator 91 is an external pilot operation type, and the pressure of the compressed air discharged from the input port 93 of the regulator 91 to the discharge port 94 is regulated by the pressure supplied to the pilot air port 92. As shown in fig. 5, an air supply passage 96 is connected to the compressed air supply source 95, and the air supply passage 96 is connected to the input port 93. The air supply passage 96 is provided with an on-off valve 97. The regulator 91 may be an internal pilot operation type, a direct-acting type, or an electric air conditioner in which the pressure is set by an electric signal as an operation handle or the like instead of the external pilot operation type.

In the liquid supply device 10b shown in fig. 4, the tubular film 15 is radially expanded through the liquid medium M by contracting the bellows 31 in the axial direction, so that the medium accommodating chamber 32 becomes negative pressure when the liquid L is injected from the liquid tank 22 into the pump chamber 16. At this time, the on-off valve 97 is opened, and the compressed air supplied from the compressed air supply source 95 is discharged to the air supply port 85 of the vacuum ejector 84. Therefore, the suction port 88 is vacuum, in other words, negative pressure is generated, and the air chamber 33 communicating with the suction port 88 through the flow path 90 is set to negative pressure in accordance with the pressure of the medium housing chamber 32. Further, the negative pressure generated by the vacuum ejector 84 by adjusting the pressure supplied from the regulator 91 may be adjusted to a value that does not deform when the bellows 31 extends, and the lever 44 may be reciprocated to contract the bellows 31 while maintaining the open/close valve 97 in an open state.

This can suppress the possibility that air in the air chamber 33 is mixed into the medium housing chamber 32 through the bellows 31, and can maintain the pump characteristic with high accuracy over a long period of time. When the bellows 31 is contracted, the bellows portion 31a is prevented from being deformed in the direction in which the average effective diameter increases in the radial direction, and the amount of the liquid L injected into the pump chamber 16 can be set with high accuracy.

The opening and closing operation of the opening and closing valve 97 is controlled in accordance with the forward rotation and the reverse rotation of the electric motor 46 by a control signal from a control unit, not shown.

In the liquid supply device shown in fig. 4, the power transmission mechanism having the belt 79 is provided between the main shaft 48 of the electric motor 46 and the feed screw shaft 51, but the electric motor 46 may be arranged so that the main shaft 48 and the feed screw shaft 51 are coaxial as in the liquid supply devices shown in fig. 1 and 2. In the liquid supply device shown in fig. 1 and 2, the main shaft 48 of the electric motor 46 may be connected to the feed screw shaft 51 via a power transmission mechanism.

Fig. 6 is a cross-sectional view showing a liquid supply device 10c according to another embodiment. The liquid supply device 10c includes a pump 11 having a tubular film 15 as a first flexible member, similar to the liquid supply devices 10a and 10b described above. The medium housing case 28 has a side wall 28b integrally provided with a top wall 28a, and an end plate 28c is attached to an opening end of the medium housing case 28. The medium housing case 28 is provided with a diaphragm 29 as a second flexible member that divides the inside into a medium housing chamber 32 and an air chamber 33, and the medium housing chamber 32 communicates with the pump housing chamber 17 through a communication hole 34.

The diaphragm 29 has an annular base portion 29a fixed between the side wall 28b and the end plate 28c, a central connecting portion 29b connected to the rod 44, and an elastically deformable portion 29c therebetween, and is integrally formed of a resin material such as a fluororesin, as in the bellows 31 described above. The rod 44 is reciprocally moved in the axial direction by the driving mechanism 27, and is reciprocally movable in the discharge direction in which the liquid medium M is supplied from the medium accommodating chamber 32 to the pump accommodating chamber 17 and in the injection direction in which the liquid medium M is returned from the pump accommodating chamber 17 to the medium accommodating chamber 32. As the driving mechanism, the rotation of the electric motor 46 may be converted into the linear reciprocating motion of the rod 44 as described above, or the rod 44 may be linearly reciprocated by the pressure of the fluid as in the case of an air pressure cylinder or the like.

In this way, the lever 44 is moved by the driving mechanism 27 in the ejection direction in which the liquid medium M is supplied from the medium accommodating chamber 32 to the pump accommodating chamber 17 and in the injection direction in which the liquid medium M is returned from the pump accommodating chamber 17 to the medium accommodating chamber 32. When the rod 44 moves in the filling direction to fill the pump chamber 16 with the liquid L from the liquid tank 22, the outer surface of the diaphragm 29 becomes a lower pressure than the inner surface. Therefore, as with the bellows 31 described above, the elastically deforming portion 29c is excessively deformed in the axial direction, and there is a concern that the liquid ejection accuracy from the pump chamber 16 is lowered. If the outer surface of the elastic deformation portion 29c is at a lower pressure than the inner surface, the gas in the air chamber 33 may permeate the resin material diaphragm 29 and be mixed into the liquid medium M having a high negative pressure. If outside air is mixed into the liquid medium M, the accuracy of liquid ejection from the pump chamber 16 may be lowered.

In order to prevent the liquid ejection accuracy from being lowered, the pressure adjusting mechanism 60 is connected to the suction hole 89 communicating with the air chamber 33 through the flow path 90 in order to lower the pressure of the air chamber 33 when the rod 44 is moved in the injection direction to reduce the volume of the air chamber 33. As the pressure adjustment mechanism 60, an air pressure control mechanism 83 shown in fig. 5 can be applied.

Fig. 7 is a cross-sectional view showing a liquid supply apparatus 10d according to still another embodiment. The pump housing 14a of the liquid supply device 10d forming the pump 11 has an inflow-side joint 18 and an outflow-side joint 19 provided at one end, and an end plate 14b is provided at the other end. A bellows 31 having the same structure as the bellows 31 shown in fig. 1 is provided as a flexible member in the pump housing 14 a. The bellows 31 as a flexible member has a bellows portion 31a, an end plate portion 31b provided at one end portion of the bellows 31, and an annular base end portion 31c provided at the other end portion, and is integrally formed of a resin material such as a fluororesin. The bellows 31a is elastically deformable in the axial direction, and the bellows 31 is a flexible pump member that expands and contracts in the axial direction as a whole. The pump housing 14a is provided with the pump chamber 16 and the air chamber 33, which are partitioned into the outer pump chamber 16 and the inner air chamber 33 by the bellows 31.

A rod 44a is attached to the end plate 31b, and the rod 44a is reciprocated in the axial direction by the drive mechanism 27. The rod 44a is reciprocatingly movable in a discharge direction for discharging the liquid in the pump chamber 16 to the outside and in a filling direction for filling the liquid into the pump chamber 16.

In this way, in the liquid supply device 10d of the system in which the bellows 31 as a flexible member incorporated in the pump housing 14 is directly expanded and contracted by the rod 44a, when the rod 44a is extended in the injection direction to inject the liquid L from the liquid tank 22 into the pump chamber 16, the outer surface of the bellows 31a of the bellows 31 is at a lower pressure than the inner surface. Therefore, when the bellows 31 is contracted in the axial direction, the bellows 31a may be slightly deformed in the radial direction so as to increase the average effective diameter of the bellows portion 31a, and the accuracy of liquid discharge from the pump chamber 16 may be lowered. If the outer surface of the bellows 31a is at a lower pressure than the inner surface, the gas in the air chamber 33 may permeate the resin bellows 31 and be mixed into the liquid medium M having a high negative pressure. If outside air is mixed into the liquid medium M, the accuracy of liquid ejection from the pump chamber 16 may be lowered.

Therefore, in order to prevent the liquid ejection accuracy from being lowered, the pressure adjusting mechanism 60 is connected to the suction hole 89 communicating with the air chamber 33 through the flow path 90 in order to lower the pressure of the air chamber 33 when the rod 44a is moved in the injection direction and the volume of the air chamber 33 is reduced. As the pressure adjustment mechanism 60, an air pressure control mechanism 83 shown in fig. 5 can be applied.

Fig. 8 is a diagram showing an air pressure circuit of the air pressure control mechanism 83 which is an example of the pressure adjustment mechanism 60 in the liquid supply device shown in fig. 6 and 7.

The air pressure control mechanism 83 has a vacuum tank 102 connected to a vacuum pump 101. The vacuum tank 102 stores a predetermined amount of negative pressure air, and functions as a buffer tank when the pressure varies. The vacuum flow path 103 connected to the vacuum tank 102 is provided with an on-off valve 97 and a regulator 104, and the flow path 90 connected to the output port of the regulator 104 is connected to the suction holes 89 of the liquid supply devices 10c and 10 d. Therefore, when the volume of the air chamber 33 is reduced to reduce the pressure of the air chamber 33, the on-off valve 97 opens the vacuum flow path 103 to supply negative pressure air to the air chamber 33.

The air pressure control means 83 of this embodiment can be applied as the air pressure control means 83 of the liquid supply device 10b shown in fig. 4.

The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit and scope thereof. For example, in the liquid supply devices 10a and 10b in which the reciprocating movement of the rod 44 increases or decreases the volume of the pump chamber 16 via the liquid medium M, the bellows 31 shown in fig. 7 or the diaphragm 29 shown in fig. 6 may be applied as the first flexible member instead of the tubular film 15. In addition, as the second flexible member, the diaphragm 29 shown in fig. 6 may be applied instead of the bellows 31.

Industrial applicability

The liquid supply device is used to supply a liquid to an object to be coated, for example, as in the case of supplying a photoresist liquid to the surface of a substrate or supplying an electrolyte liquid to a battery container.

Claims

1. A liquid supply device including a first flexible member disposed in a pump housing and separating a pump chamber and a pump housing chamber, the liquid supply device including:

a medium housing case having a second flexible member that partitions a medium housing chamber and an air chamber that communicate with the pump housing chamber;

a liquid medium filled in the pump housing chamber and the medium housing chamber;

a driving member that reciprocates a lever attached to the second flexible member in a discharge direction in which the liquid medium is supplied from the medium accommodating chamber to the pump accommodating chamber and in an injection direction in which the liquid medium is returned from the pump accommodating chamber to the medium accommodating chamber; and

and a pressure adjustment mechanism that reduces the pressure of the air chamber when the rod is driven in the injection direction and the volume of the air chamber is reduced.

2. The liquid supply apparatus according to claim 1, wherein,

the pressure adjustment mechanism has: a cylinder body having a pressure adjustment chamber communicating with the air chamber; and a pressure regulating piston which is housed in the cylinder body so as to be movable in an axial direction in a reciprocating manner,

the pressure regulating piston sucks air in the air chamber to the pressure regulating chamber when the rod is driven in the injection direction to reduce the volume of the air chamber, and supplies air in the pressure regulating chamber to the air chamber when the rod is driven in the discharge direction to increase the volume of the air chamber.

3. The liquid supply apparatus according to claim 2, wherein,

a positive pressure release valve is provided in the pressure regulating piston, the positive pressure release valve discharging air in the pressure regulating chamber to the outside when the pressure in the pressure regulating chamber is higher than the allowable positive pressure,

the pressure-adjusting piston is provided with a negative pressure release valve that supplies air into the pressure-adjusting chamber when the pressure in the pressure-adjusting chamber is lower than the allowable negative pressure.

4. A liquid supply apparatus according to claim 2 or 3, wherein,

the pressure regulating piston is provided to the rod, and the second flexible member is reciprocated by the rod in synchronization with the pressure regulating piston.

5. The liquid supply apparatus according to claim 1, wherein,

the pressure adjustment mechanism is a vacuum ejector, and the vacuum ejector includes: an air supply port in communication with an air supply source; a diffuser injecting compressed air supplied from the air supply port; and a suction port communicating with the diffuser and communicating with the air chamber.

6. The liquid supply apparatus according to claim 5, wherein,

an opening/closing valve is provided in an air supply passage between the air supply port and a supply source of compressed air, and the opening/closing valve opens the air supply passage when the rod is moved in the injection direction to return the liquid medium from the pump housing chamber to the medium housing chamber.

7. The liquid supply apparatus according to claim 5, wherein,

the liquid supply device includes: an opening/closing valve provided in an air supply passage between the air supply port and a supply source of compressed air, and a regulator provided between the opening/closing valve and the air supply port and regulating a pressure of the compressed air supplied to the air supply port, wherein the lever is reciprocally moved in a state in which the opening/closing valve opens the air supply passage.

8. The liquid supply apparatus according to claim 1, wherein,

the pressure adjustment mechanism is a vacuum pump having a vacuum flow path communicating with the air chamber.

9. The liquid supply apparatus according to claim 8, wherein,

an opening/closing valve is provided in the vacuum flow path, and the opening/closing valve opens the vacuum flow path when the rod is moved in the injection direction to return the liquid medium from the pump housing chamber to the medium housing chamber.

10. The liquid supply apparatus according to any one of claims 1 to 9, wherein,

the first flexible member is a tubular film that is elastically deformable in the radial direction and is provided with the pump chamber on the inside and the pump housing chamber on the outside, a bellows that is elastically deformable in the axial direction and is provided with the pump chamber on the inside and the pump housing chamber on the outside, or a diaphragm that is elastically deformable in the axial direction and is provided with the pump chamber on the outside and the pump housing chamber on the inside.

11. The liquid supply apparatus according to any one of claims 1 to 10, wherein,

the second flexible member is a bellows which is elastically deformable in the axial direction and is provided with the air chamber on the inside and the medium accommodating chamber on the outside, or a diaphragm which is elastically deformable in the axial direction and is provided with the medium accommodating chamber on the outside and the air chamber on the inside.

12. A liquid supply device including a flexible member disposed in a pump housing and separating a pump chamber and an air chamber, the liquid supply device including:

a driving member that reciprocates a rod attached to the flexible member in a discharge direction in which the liquid in the pump chamber is discharged to the outside and in an injection direction in which the liquid is injected into the pump chamber; and

and a pressure adjustment mechanism that reduces the pressure of the air chamber when the rod is moved in the injection direction and the volume of the air chamber is reduced.

13. The liquid supply apparatus according to claim 12, wherein,

the flexible member is a bellows that is elastically deformable in the axial direction and has the pump chamber on the outside and the air chamber on the inside, or a diaphragm that is elastically deformable in the axial direction and has the pump chamber on the outside and the air chamber on the inside.