JP2003049778A - Liquid feeder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid feeder that can quantitatively discharge a trace quantity of liquid with more accuracy by using a pressure sensor with high corrosion resistance, responsiveness and heat resistance. SOLUTION: The liquid feeder 50 changes the volume of a pump chamber 55 by driving a diaphragm 52 to suction a chemical from an input port 81 and discharge the chemical to an output port 82. A wall surface of the pump chamber 55 is partly formed by a sensor surface 72 of the pressure sensor 70, and the sensor surface 72 is provided with a fluorine resin 71 by thermo- compression bonding. The pressure sensor 70 measures a back pressure generated by, for example, an orifice arranged outside the output port 82, and passes feedback to a controller 64. According to the measured value, the controller 64 controls a solenoid-operated proportioning valve 65 for driving the diaphragm 52.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid supply device capable of stably and quantitatively discharging a minute amount of chemical liquid.

[0002]

2. Description of the Related Art In a semiconductor manufacturing process, a very small amount of chemical solution such as resist solution is required to be discharged. Therefore, a liquid supply device for quantitatively discharging such a minute amount of chemical liquid has been conventionally proposed, and the present applicant proposes the liquid supply device 100 shown in FIG. 7 in Japanese Patent Laid-Open No. 11-343978. is doing.

In the liquid supply apparatus 100, the diaphragm 10 is adjusted by adjusting the pressure in the pressurizing chamber 112 of the diaphragm pump 101 with the electronic regulator 129.
3 is deformed, and the chemical liquid filled in the pump chamber 111 is discharged from the output port 114 to the discharge pipe 124. The discharge pipe 124 is provided with a pressure sensor 125, an output valve 126, and an orifice 127 in this order from the output port 114 side, and since the flow rate of passage is limited by the orifice 127, the chemical liquid in the upstream flow path of the orifice 127 is restricted. Is back pressured. This pressure is measured by the pressure sensor 125,
Since the signal is fed back to the controller 131, the controller 131 controls the electronic regulator 129 so that it becomes a target set pressure. by this,
A small amount of chemical solution is dispensed.

In the liquid supply apparatus 100 as described above, generally, a corrosive chemical liquid is circulated, and therefore, all the liquid contact parts in the flow path are required to have corrosion resistance to the chemical liquid. this is,
Diaphragm pump 101, supply pipe 122, discharge pipe 12
The same applies to the pressure sensor 125 as well as 4 and the like. That is, the pressure sensor 1 in which the metal sensor surface is exposed
At 25, the sensor surface is corroded. Then, the pressure sensor 125 is deteriorated, and the metal is mixed in the chemical liquid, which changes the property of the chemical liquid and cannot be used.

Therefore, the PTF of fluororesin has hitherto been used.
A pressure sensor 125 in which E (tetrafluoroethylene resin) is adhered to the liquid contact portion is used. Although PTFE is a substance having high corrosion resistance, it also has high non-adhesiveness that makes it difficult for substances to stick together. Therefore, the surface of the pressure sensor 1 is treated with a chemical etching method so that the pressure sensor 1 can be easily bonded.
It became possible to adhere to the wetted part of 25.
As a result, the pressure sensor 125 having high corrosion resistance was obtained, and by using this pressure sensor 125, the liquid supply device 100 capable of discharging a minute amount of the chemical liquid was obtained.

[0006]

However, as a result of close examination in recent years with further progress in semiconductor manufacturing technology, the present inventors have found that the liquid supply device 100 has a slight error in the output amount. did. That is, as shown in FIG. 9, the liquid pressure output from the conventional liquid supply apparatus 100 stabilizes at a target value about 40 seconds after the start of output, and is 0.5 at 1.5 seconds after the start of pressurization. % F. S. There was some error. In the precise semiconductor manufacturing process,
Even such an error is not preferable because it may cause a decrease in product yield.

Then, when the cause was further investigated,
The inventors have discovered that the pressure sensor 125 has a problem. In the conventional pressure sensor 125, the sensor surface and PT
An adhesive agent was present between the FE film and the adhesive agent, and the responsiveness of the pressure sensor 125 was lowered. FIG. 8 is a graph showing the response of the conventional pressure sensor 125. Figure 8
As shown in FIG.
After 9 seconds, 99.5% F. S. And 1 after about 40 seconds
It is 00%.

Further, the present inventors have also found that the pressure sensor 125 of this type is deteriorated by heat due to heat change of the adhesive. This pressure sensor 125
FIG. 10 shows the result of examining the state of deterioration under various temperature environments. As shown in FIG. 10, by changing the temperature environment, the output result of the pressure sensor 125 greatly changes, and after adding about 65 ° C., the performance is not changed even after being left at 25 ° C. overnight. You can see that it is not returning.

That is, PT is formed by using the chemical etching method.
The pressure sensor 125 in which FE is adhered to the sensor surface has excellent corrosion resistance, but on the other hand, there is room for further improvement in responsiveness, and there is a further problem of thermal deterioration. Therefore, the liquid supply apparatus 10 using this pressure sensor 125
In the case of 0, there is a problem that it may not be suitable for the future semiconductor manufacturing process which becomes more precise.

On the other hand, thermocompression bonding is known as another method for adhering a fluororesin to a substrate.

The present invention has been made to solve the above problems, and more accurately and quantitatively discharges a small amount of liquid by using a pressure sensor having high corrosion resistance, responsiveness, and heat resistance. It is an object of the present invention to provide a liquid supply device that enables the above.

[0012]

In the liquid supply apparatus of the present invention, a part of the pump chamber is formed by a volume variable member, and the volume of the pump chamber is changed by driving the volume variable member to suck or discharge the liquid. A pump, an orifice provided in a discharge passage on the liquid discharge side communicating with the pump chamber of the pump, a pressure detection unit for measuring the liquid pressure in the discharge passage on the upstream side of the orifice, In a liquid supply device comprising a drive means for driving a volume variable member and a control means for controlling the drive means based on a measurement value by the pressure detection means, a fluorine resin is heated on a sensor surface of the pressure detection means. It is characterized by being crimped.

Therefore, according to the present invention, since the volume of the pump chamber is changed by the volume varying member driven by the drive means, the liquid can be discharged from the pump chamber to the discharge passage. Further, since the discharge flow passage is provided with an orifice and the flow rate of the passage is limited, a back pressure is applied to the flow passage on the upstream side of the orifice, and the pressure is measured by the pressure detection means. Further, based on the measurement value measured by the pressure detection means, the control means controls the drive means to drive the volume variable member. Therefore, the liquid pressure in the upstream flow path of the orifice is maintained constant and the flow rate of the liquid passing through the orifice is always constant, so that a very small amount of liquid is accurately and quantitatively discharged from this liquid supply device.

Further, according to the present invention, since the fluororesin is thermocompression-bonded to the sensor surface of the pressure detecting means, no adhesive agent is interposed between the sensor surface and the fluororesin. Therefore, since there is no decrease in responsiveness or thermal deterioration due to the adhesive, the pressure detecting means has further improved responsiveness and high durability. As a result, the pressure of the liquid in the flow passage on the upstream side of the orifice can be measured with higher responsiveness.
Accurate measurement is possible even if the environment changes. Therefore, the target pressure can be maintained with higher responsiveness, and the flow rate of the liquid passing through the orifice can be kept constant with higher responsiveness. Therefore, a very small amount of liquid can be more accurately quantified from the liquid supply device. Is ejected.

In the liquid supply device of the present invention, a part of the pump chamber is formed by a variable volume member, and the volume of the pump chamber is changed by driving the variable volume member to suck or discharge the liquid. An output valve that opens and closes a liquid discharge side flow path that communicates with the pump chamber of the pump, an input valve that opens and closes a liquid suction side flow path that communicates with the pump chamber of the pump, and a discharge side flow path are provided. Based on the measured value by the output port, the fluororesin is thermocompression-bonded to the sensor surface, the pressure detecting means for measuring the liquid pressure in the pump chamber, the driving means for driving the variable volume member, and the pressure detecting means. The control means for controlling the driving means is integrally configured.

Therefore, according to the present invention, since the volume of the pump chamber is changed by driving the variable volume member, by opening and closing the input valve and the output valve accordingly,
Liquid can be sucked or discharged into the pump chamber. Then, the pressure in the upstream flow passage from the output port of the discharge side flow passage is measured by the pressure detecting means. Further, based on the measurement value measured by the pressure detection means, the control means controls the drive means to drive the volume variable member. for that reason,
Since the liquid pressure in the upstream flow passage of the output port is maintained constant and the flow rate passing through the output port is always constant, a very small amount of liquid is accurately and quantitatively discharged from this liquid supply device.

Further, according to the present invention, since it is integrally formed, it is compact, and handling such as mounting and dismounting is easy. Further, since the pressure detecting means measures the liquid pressure in the pump chamber, a joint or a pipe for connecting the pump chamber and the pressure detecting means becomes unnecessary, and the amount of the liquid whose pressure is measured becomes small. Therefore, the change in pressure appears more quickly, and the pressure detection means enables measurement with better responsiveness. Therefore, the flow rate of the liquid passing through the output port can be made constant with even higher responsiveness, so that a very small amount of liquid is more accurately and quantitatively discharged from the liquid supply device.

Further, the liquid supply apparatus of the present invention is defined in claim 2.
In the liquid supply device according to the item (1), the variable volume member of the pump is a linear piston driven by a piston rod, and the sensor surface of the pressure detection unit is a part of a wall surface of the pump chamber. And the axis of the piston rod is substantially orthogonal to the center of the sensor surface.

Therefore, according to the present invention, since the sensor surface of the pressure detecting means forms a part of the wall surface of the pump chamber, the liquid pressure in the pump chamber is directly applied to the sensor surface. Therefore, the liquid pressure in the pump chamber can be measured with good responsiveness by the pressure detecting means. Further, since the variable volume member is driven by the linear piston, the change in the liquid pressure in the pump chamber due to the change in the volume in the pump chamber is first transmitted in the axial direction of the piston rod. Since the axis of the piston rod is substantially orthogonal to the center of the sensor surface, the change in liquid pressure in the pump chamber is transmitted in a direction substantially orthogonal to the most sensitive center of the sensor surface. Therefore, the responsiveness of the pressure detecting means is improved, and the flow rate of the liquid passing through the output port can be made constant with even better responsiveness.
A very small amount of liquid is more accurately and quantitatively discharged from this liquid supply device.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION (First Embodiment) A first embodiment of the liquid supply apparatus of the present invention will be described in detail below with reference to the drawings. FIG. 1 shows a block diagram of a liquid supply apparatus according to a first embodiment of the present invention. The liquid supply apparatus 1 has a diaphragm pump 20 as a main part, and discharges a liquid (for example, a chemical solution in a semiconductor manufacturing process) supplied to the diaphragm pump 20 in a fixed amount.

As shown in FIG. 1, the diaphragm pump 2
0 indicates that the space formed in the body 2 is the diaphragm 3
Is divided into two chambers, a pump chamber 11 for filling the chemical liquid and a pressurizing chamber 12 for supplying air as a working fluid. The body 2 is provided with an input port 13 for supplying a chemical liquid and an output port 14 for discharging the filled chemical liquid, which penetrate the pump chamber 11. A supply / exhaust port 15 for supplying / exhausting air is formed in the body 2 and penetrates into the pressurizing chamber 12. Here, the diaphragm 3 corresponds to the variable volume member according to claim 1.

Further, the diaphragm pump 20 is provided with a fluid portion formed by the pump chamber 11 and the pressurizing chamber 12 in the body 2 as described above, and is provided with a support portion for stably operating the diaphragm 3. ing. In the support portion, a piston rod 5 vertically fixed to a central position of the diaphragm 3 via a fixing plate 4 penetrates a linear guide 6 such as a bush loaded in the body 2 to drive the diaphragm 3 in a well-balanced manner. Is configured. An O-ring 7 is fitted in the penetrating portion of the body 2 penetrated by the piston rod 5 so as to make the interior of the pressurizing chamber 12 airtight. A disk 8 is fixed to the tip of the piston rod 5 penetrating the linear guide 6, and the piston rod 5 is urged to the right in the figure by a spring 9 in contact with the disk 8. Further, a marker 10 projecting from the body 2 is fixed on the extension of the piston rod 5, and the displacement of the diaphragm 3 can be measured by a position detection sensor 21 that measures the position of the marker 10 using a differential transformer. Is configured.

In the liquid supply apparatus 1, a supply pipe 22 is connected to the input port 13 of the diaphragm pump 20 and is connected to a chemical liquid supply source (not shown). And
An electromagnetic input valve 23 is provided in the middle of the supply pipe 22 so as to control the inflow of the chemical liquid from the chemical liquid supply source to the diaphragm pump 20. On the other hand, a discharge pipe 24 is connected to the output port 14 of the diaphragm pump 20 and is connected to a chamber device (not shown). The discharge pipe 24 is provided with a pressure sensor 25, an electromagnetic output valve 26, and an orifice 27 in this order from the diaphragm pump 20 to the discharge side. The liquid supply apparatus 1 quantitatively discharges a very small amount of chemical liquid of 1 cc or less per minute, and the diameter of the orifice 27 is also extremely small, for example, 20 μm. Therefore, the flow of the chemical liquid is restricted by the orifice 27, and thereby the back pressure in the discharge pipe 24 is measured by the pressure sensor 25.

A supply / exhaust pipe 28 is connected to the supply / exhaust port 15 of the diaphragm pump 20 and is connected to an electronic regulator 29. This electronic regulator 29
Is for adjusting the air pressure in the pressurizing chamber 12 of the diaphragm pump 20. In addition, the input valve 23,
Output valve 26, pressure sensor 25, electronic regulator 2
A controller 31 is electrically connected to 9 and the position detection sensor 21. The controller 31 is provided with a program for feedback-controlling the electronic regulator 29 so as to open and close the input valve 23 and the output valve 26 at a predetermined timing and to quantitatively discharge the chemical liquid based on the signal from the pressure sensor 25. It is a thing. Here, the electronic regulator 29 corresponds to the driving means described in claim 1, and the controller 31 corresponds to the control means described in claim 1.

Here, as the liquid circulated in the liquid supply apparatus 1, for example, a corrosive liquid such as a chemical liquid in a semiconductor manufacturing process is assumed. Therefore, all the parts that come into contact with the liquid are made of a corrosion-resistant material such as fluororesin. That is, the inner wall of the pump chamber 11 of the diaphragm pump 20, the diaphragm 3, the supply pipe 22, the discharge pipe 2
4, the liquid contact portion of the input valve 23 and the output valve 26, the orifice 27, and the liquid contact portion of the pressure sensor 25. The components other than the pressure sensor 25 may be made of fluororesin, for example, the diaphragm 3
The supply pipe 22, the discharge pipe 24, etc. are made of PTFE. Further, the liquid contact portions of the input valve 23 and the output valve 26 are formed by the method of bonding PTFE with an adhesive by the chemical etching method described in the section of the prior art.

On the other hand, fluororesin is thermocompression bonded to the sensor surface of the pressure sensor 25, which is the liquid contact portion. As shown in the partial cross-sectional view of FIG. 2, the pressure sensor 25 has a sensor unit 41 for measuring pressure, to which a pressure transmitter 42 for converting the measured pressure value into a signal is fixed. A cable 43 for transmitting the signal to the controller 31 is connected. And, the sensor cover 44 that covers all of them has
Openings are provided on both sides, and the opening 44 on one end side is formed.
A sensor section 41 is fixed to p, and a cable 43 held by a grommet 45 is projected and fixed to the opening 44q on the other end side.

Further, the sensor portion 41 has a sensor surface portion 46 having a sensor surface for sensing pressure, and a sensor cover 44.
A peripheral edge portion 47 for being attached to the O-ring 48
The structure is fixed via. Then, the peripheral edge portion 47 is arranged so as to project from the opening portion 44p on the one end side of the sensor cover 44. The fluororesin 49 is thermocompression-bonded to the liquid contacting portion between the sensor surface portion 46 and the peripheral edge portion 47 of the sensor portion 41 arranged in this way. That is,
PFA (or FEP) and PTFE are overlapped and brought into close contact with the liquid contact portion, and heat and pressure are applied, so that the fluororesin 49 (here, PTFE) is adhered.

The liquid supply apparatus 1 thus constructed is
It is operated under the control of the controller 31. When the chemical liquid is discharged from the pump chamber 11 filled with the chemical liquid, the input valve 23 is closed and the output valve 26 is opened, and air is supplied to the pressurizing chamber 12 by the electronic regulator 29.
The diaphragm 3 is pushed by the air pressure and moves in a direction to reduce the volume of the pump chamber 11. Therefore, the chemical liquid in the pump chamber 11 is discharged from the output port 14 to the discharge pipe 24. Since the orifice 27 is provided in the middle of the discharge pipe 24 to limit the flow rate, a back pressure is applied to the flow path between the orifice 27 and the pump chamber 11 on the upstream side. Then, the pressure inside the flow passage on the upstream side of the orifice 27 is measured by the pressure sensor 25 and fed back to the controller 31, so the controller 31 controls the electronic regulator 29 to maintain the inside of the flow passage at the target pressure. Therefore, since the fluid pressure applied to the orifice 27 is always constant, a minute amount of the chemical liquid can be discharged in a fixed amount.

After the discharge is completed, next, the controller 3
1, the output valve 26 is closed, the input valve 23 is opened, the air in the pressurizing chamber 12 is discharged from the air supply / exhaust port 15, and the diaphragm 3 is moved to the right in the figure by the urging force of the spring 9. The volume of the pump chamber 11 is increased.
As a result, the chemical liquid is supplied from the chemical liquid supply source to the input port 13 via the supply pipe 22 and the pump chamber 11 is filled with the liquid, so that the chemical liquid reduced by the discharge is replenished.

The performance of the pressure sensor 25 used in the liquid supply apparatus 1 will be compared with that of the pressure sensor 125 in which a fluororesin is adhered with an adhesive as described in the section of the prior art to explain the difference. First, the responsiveness of the pressure sensor 25 is as shown in FIG.
sec 100%, and about 99.5% F.S. S. Has become. The conventional pressure sensor 125 is 100% F.S. S. It can be seen that the responsiveness is extremely good as compared with the case where it took 40 seconds to reach. Further, regarding the thermal deterioration, the result of the same experiment as shown in FIG. 10 is shown in FIG. Figure 4
As shown in, even if there is a deviation in the measured value due to environmental changes, it is almost restored by leaving it at 25 ° C. overnight. Therefore, it can be seen that this pressure sensor 25 has very good responsiveness as compared with the conventional pressure sensor 125 and hardly undergoes thermal deterioration.

The pressure of the liquid discharged from the liquid supply apparatus 1 using the pressure sensor 25 was examined by an experiment, and as shown in FIG. 5, the target pressure was almost reached 1.5 seconds after the start of pressurization. , Then stable. As shown in FIG. 9, in the conventional liquid supply apparatus 100, the liquid supply apparatus 1 has very good responsiveness as compared with the case where it took 40 seconds to stabilize the target value. Recognize. Therefore, since the liquid supply apparatus 1 can discharge the target discharge amount from 1.5 seconds after the start of operation, a very small amount of the chemical liquid can be discharged very accurately in a fixed amount.

As described above, according to the liquid supply apparatus 1 of the first embodiment, since all the parts that come into contact with the chemical solution are made of PTFE, which has a high corrosion resistance, they are eroded by the chemical solution, It does not melt into and change its properties. Further, since the pressure sensor 25 can measure the pressure with good responsiveness, the change in the back pressure of the orifice 27 can be measured with good responsiveness and is fed back by the controller 31. Therefore, the back pressure of the orifice 27 can be constantly maintained at a constant pressure, and thus the flow rate of the chemical liquid discharged from the orifice 27 can be kept constant.
Further, since the pressure sensor 25 is not thermally deteriorated, it is possible to stably discharge a fixed amount of the chemical liquid without being affected by a change in environment. As a result, the liquid supply device 1 accurately discharges a minute amount of the liquid medicine.

(Second Embodiment) A second embodiment of the liquid supply apparatus of the present invention will be described in detail below with reference to the drawings. FIG. 6 shows a second embodiment of the present invention.
FIG. 3 is a cross-sectional view of the liquid supply device of the embodiment. This liquid supply device 50 is an integrated part of the liquid supply device 1 of the first embodiment except for the orifice 27, and supplies a fixed amount of liquid (for example, a chemical solution in a semiconductor manufacturing process). It is designed to be discharged.

As shown in FIG. 6, the pump portion 51 of the liquid supply device 50 has substantially the same structure as the diaphragm pump 20 of the first embodiment. In the fluid portion of the pump portion 51, the diaphragm 52 is a body 53 made of PTFE.
A pump chamber 55 that is sandwiched and fixed by the cover 54 and filled with liquid by the diaphragm 52 and the body 53; and a pressurizing chamber 56 that supplies air, which is a working fluid, by the diaphragm 52 and the cover 54. ,
Each is formed.

Further, the support portion of the pump portion 51 is arranged such that a piston rod 58 vertically fixed to a central position of the diaphragm 52 via a fixing portion 57 penetrates the cover 54 and is movable in the axial direction. There is. Further, a disc 59 is fixed to the center of the piston rod 58, and the disc 59 is fixed.
By the spring 60 abutting on the piston rod 5
8 and diaphragm 52 are urged to the left in the figure.
A marker 61 is fixed to the other end of the piston rod 58,
Around the marker 61, a position detection sensor 62 that detects the position of the marker 61 is provided.

The support portion of the pump portion 51 is a cover 54.
It is housed in a case 63 that is fixed to the inside of the case 63. In addition, inside the case 63, a controller 64 that controls the liquid supply device 50, an electromagnetic proportional valve 65 that adjusts the air pressure supplied to the pressurizing chamber 56, and ON / OFF the flow paths of operating air to the input valve 83 and the output valve 84, respectively.
A solenoid valve (not shown) or the like is incorporated and integrally configured. An input terminal 66 for inputting a signal to the controller 64 projects on the outer surface of the case 63, and an air input port 67 for connecting to an air source (not shown) and inputting operating air is opened.

A pump chamber 55 of the pump portion 51 is formed in the body 53 and a pressure sensor 70 is fixed. The pressure sensor 70 has the same configuration as the pressure sensor 25 (see FIG. 2) of the first embodiment,
The sensor surface 72 to which the fluororesin 71 is thermocompression bonded forms a part of the wall surface of the pump chamber 55. The pressure sensor 70 is arranged to face the fixed portion 57 of the diaphragm 52 so that the extension line of the central axis of the piston rod 58 is substantially orthogonal to the substantially center of the sensor surface 72. Further, the pressure sensor 70 is provided with a wiring 73 for transmitting the measured pressure value to the controller 64, and is connected to the controller 64.

Further, as shown in FIG. 6, the body 53 has an input port 81 connected to a chemical liquid supply source (not shown), an output port 82 connected to a chamber device (not shown), and a chemical liquid from the input port 81. An input valve 83 for turning on / off the input and an output valve 84 for turning on / off the discharge of the chemical liquid to the output port 82 are fixed. Then, the communication passages 85, 86, 87, 88 formed in the body 53
Are communicated with each other. That is, the input port 81 communicates with the pump chamber 55 through the communication passage 85, the input valve 83, and the communication passage 86, and the pump chamber 55
Are communicated with the output port 82 via the communication passage 87, the output valve 84, and the communication passage 88. An orifice (not shown) is attached to the outside of the output port 82 to limit the discharge flow rate of the chemical liquid. Here, the input port 81, the output port 82,
The liquid contact portions of the input valve 83 and the output valve 84 are made of PTFE or are made by adhering PTFE.

An operation in which a very small amount of the chemical liquid is quantitatively discharged by the liquid supply device 50 having the above-described structure will be described. FIG. 6 shows a state where the air pressure in the pressurizing chamber 56 is reduced and the urging force of the spring 60 causes the piston rod 58 and the diaphragm 52 to be at the leftmost position in the drawing. Therefore, the pump chamber 55 has the maximum capacity and is filled with the chemical liquid. When the discharge is instructed, the controller 64 drives the electromagnetic proportional valve 65 to supply the operating air input from the air input port 67 to the pressurizing chamber 56, so that the pressurizing chamber 56 is pressurized. The diaphragm 52 is moved rightward in the figure to reduce the volume of the pump chamber 55. Further, the input valve 83 is closed and the output valve 84 is opened, and the chemical liquid pushed out from the pump chamber 55 by the diaphragm 52 is output to the output port 82 via the output valve 84.

At this time, an orifice (not shown) or the like is attached to the outside of the output port 82 to limit the output flow rate and apply back pressure. This back pressure is measured by the pressure sensor 70, and the measured value is fed back to the controller 64. The controller 64 controls the electromagnetic proportional valve 6 so that the back pressure fed back becomes a predetermined constant pressure.
Control 5 Therefore, since the pressure of the chemical liquid applied to the output port 82 is always a predetermined constant pressure, a minute amount of the chemical liquid is discharged in a fixed amount. At this time, the sensor surface 72 of the pressure sensor 70
Since the fluororesin 71 is thermocompression bonded to, the responsiveness is good and the thermal deterioration does not occur. When the discharge is completed, the output valve 84 is closed and the input valve 83 is opened, and the pressurizing chamber 5
By depressurizing the air of 6, the volume of the pump chamber 55 is increased, and the pump chamber 55 is filled with the chemical liquid from the chemical liquid supply source.

As described above, according to the liquid supply apparatus 50 of the second embodiment, since all the parts which come into contact with the chemical liquid are made of PTFE having a high corrosion resistance, they are eroded by the chemical liquid or the chemical liquid is eroded. It does not melt into and change its properties. Further, since the fluororesin 71 is thermocompression bonded to the sensor surface 72 of the pressure sensor 70, the pressure is detected with good responsiveness without the influence of the adhesive. Further, since the pressure sensor 70 is not deteriorated by heat, it is possible to stably discharge a fixed amount of the chemical liquid without being affected by a change in environment. In addition, the flow passage volume from the output port 82 to the pump chamber 55 is small, and the sensor surface 72 of the pressure sensor 70 is small.
Since it constitutes a part of the inner wall of the pump chamber 55, the amount of the drug solution whose pressure is to be measured is small, and the response can be measured with good response. Further, since the axis of the piston rod 58 is substantially orthogonal to the center of the sensor surface 72, the change in the pressure inside the pump chamber 55 due to the movement of the piston rod 58 can be more sensitively measured by the sensor surface 72. As a result, the liquid supply device 50 accurately discharges a minute amount of the liquid medicine.

The present invention is not limited to the above-mentioned embodiment, and various modifications can be made without departing from the spirit of the invention. (1) In the first and second embodiments, the diaphragm has been described as the variable volume member, but a bellows, a bellows, a piston or the like may be used instead. (2) Further, in the first and second embodiments, the fluid pressure of the working fluid by air is used as the driving force to drive the diaphragm, but the stepping motor is used as the driving means without using the fluid. It may be one. (3) Further, in the first and second embodiments, the differential transformer is used as the position detection sensor for the displacement measurement of the diaphragm, but a potentiometer, a laser displacement meter or the like may be used. (4) Further, in the second embodiment, the air-driven ones are used as the input valve and the output valve, but other driving force such as an electromagnetic valve may be used.

[0043]

According to the configuration of the invention described in claim 1,
Since the fluororesin is thermocompression-bonded to the sensor surface of the pressure detecting means, the response is good and there is no thermal deterioration. Therefore, according to the configuration of the present invention, the liquid pressure on the upstream side of the orifice is maintained constant. As a result, it is possible to accurately discharge a minute amount of the liquid medicine output from the liquid supply device.

According to the second aspect of the invention, since the fluororesin is thermocompression-bonded to the sensor surface of the pressure detecting means, the response is good and no thermal deterioration occurs. Therefore, according to the configuration of the present invention, the liquid pressure on the upstream side of the output port is maintained constant. As a result, it is possible to accurately discharge a minute amount of the liquid medicine output from the liquid supply device. Furthermore, since it is integrally configured, it is compact and easy to handle. Further, since the pressure detecting means measures the liquid pressure in the pump chamber, it is possible to detect the pressure with a better responsiveness. Therefore, it is possible to more accurately discharge a fixed amount.

According to the structure of the invention described in claim 3, in addition to the effect of the invention of claim 2, the axis of the piston rod for driving the volume variable member for changing the volume of the pump chamber is substantially the sensor surface. Since it is substantially orthogonal to the center, the responsiveness of the pressure detecting means is further improved. Therefore, it is possible to more accurately discharge a fixed amount.

[0046]

[Brief description of drawings]

FIG. 1 is a block diagram showing a liquid supply device according to a first embodiment.

FIG. 2 is a partial cross-sectional view showing a pressure sensor.

FIG. 3 is a graph showing the response of the pressure sensor.

FIG. 4 is a graph showing the thermal variability of the pressure sensor.

FIG. 5 is a graph showing the response of the liquid supply device.

FIG. 6 is a cross-sectional view showing a liquid supply device according to a second embodiment.

FIG. 7 is a block diagram showing a conventional liquid supply device.

FIG. 8 is a graph showing the response of a conventional pressure sensor.

FIG. 9 is a graph showing the response of a conventional liquid supply device.

FIG. 10 is a graph showing the thermal variability of a conventional pressure sensor.

[Explanation of symbols]

1 Liquid supply device 3 diaphragm (variable volume member) 11 pump room 20 diaphragm pump 25 Pressure sensor (pressure detection means) 27 Orifice 29 Electronic regulator (driving means) 31 controller (control means) 46 Sensor surface 49 Fluorine resin 50 Liquid supply device 51 Pump section 52 Diaphragm (variable volume member) 55 Pump room 58 Piston rod 64 controller (control means) 65 Electromagnetic proportional valve (driving means) 70 Pressure sensor (pressure detection means) 71 Fluororesin 72 Sensor surface 82 Output port 83 Input valve 84 Output valve

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiroshi Kagohashi             850, Horinouchi Town, Kasugai City, Aichi Prefecture             Hardy Co., Ltd. Kasugai Office F term (reference) 3H075 AA09 BB04 BB14 BB30 CC11                       CC30 CC32 CC36 DA05 DB01                       DB42 DB48 DB49 EE08 EE12                 3H077 AA08 CC02 DD01 DD14 EE01                       EE05 EE15 EE34 FF03 FF22                       FF45 FF55 FF57                 4F042 AA07 AB00 BA06 BA11 CB02                       CB03 CB10 CB11                 5F046 JA01 JA27

Claims (3)

[Claims] 1. A pump that forms a part of a pump chamber with a variable volume member, and that drives the variable volume member to change the volume in the pump chamber to suck or discharge liquid, and is connected to the pump chamber of the pump. An orifice provided in the discharge flow passage on the liquid discharge side, a pressure detection means for measuring the liquid pressure in the discharge flow passage upstream of the orifice, a drive means for driving the volume variable member, and the pressure A liquid supply apparatus comprising: a control unit that controls the drive unit based on a measurement value of the detection unit, wherein a fluororesin is thermocompression-bonded to the sensor surface of the pressure detection unit. 2. A pump which forms a part of a pump chamber with a variable volume member, and which drives the variable volume member to change the volume of the pump chamber to suck or discharge liquid, and is connected to the pump chamber of the pump. An output valve that opens and closes the liquid discharge side flow path, an input valve that opens and closes the liquid suction side flow path that communicates with the pump chamber of the pump, an output port provided in the discharge side flow path, and a sensor surface Fluororesin is thermocompression bonded, pressure detection means for measuring the liquid pressure in the pump chamber, drive means for driving the volume variable member, and control means for controlling the drive means based on the measurement value by the pressure detection means. A liquid supply device comprising: 3. The variable volume member of the pump is driven by a linear piston by a piston rod, and the sensor surface of the pressure detecting means forms a part of a wall surface of the pump chamber, The liquid supply apparatus according to claim 2, wherein an axis of the piston rod is substantially orthogonal to a center of the sensor surface.