JP6434741B2 - System for reducing pump pulsation - Google Patents

Description

  The present invention relates to a system for reducing pump pulsation, and to a system for reducing pulsation of discharged fluid caused by expansion and contraction of a bellows pump.

  2. Description of the Related Art Conventionally, bellows pumps have been widely used in fields where contamination of impurities is particularly strictly limited when transferring a desired fluid, such as supply of a high-purity chemical solution in the manufacture of semiconductors and liquid crystal display devices, and quantitative injection of pharmaceuticals.

  The bellows pump is generally composed of a bellows, a driving device for expanding and contracting the bellows, and a suction check valve and a discharge check valve connected to the bellows. When the bellows extends through the drive device, fluid flows into the bellows through the suction check valve, and when the bellows contracts, the fluid is discharged from the discharge port through the discharge check valve. It is configured.

  FIG. 4 is a schematic diagram for explaining an outline of a conventional pump system using a bellows pump.

  The conventional pump system 3 includes a liquid process line 300 that is configured around the bellows pump 150 and a device arrangement area 200 that supplies air to the bellows pump 150.

  The device arrangement area 200 includes an intake port 100, an air regulator 110, and an electromagnetic valve 130. Between the intake port 100 and the air regulator 110 and between the air regulator 110 and the electromagnetic valve 130, pipes 11 and 14, respectively. Communicate. Air sucked from the air inlet 100 enters the air regulator 110 via the pipe 11. Next, a predetermined pressure adjustment is performed in the air regulator 110 and supplied to the solenoid valve 130 via the pipe 14. By switching the solenoid valve 130, air is supplied to the liquid process line 300 via the pipe 17 or 19.

  The liquid process line 300 includes a bellows pump 150 and two quick exhaust valves 162 and 164. The pipe 17 communicates with the quick exhaust valve 164, and the pipe 19 communicates with the quick exhaust valve 162.

  The air supplied from the pipe 17 is supplied to the bellows pump 150 (left side in FIG. 4) via the quick exhaust valve 164 and the pipe 21. Along with the supply of air, the bellows provided on the left side in the bellows pump 150 is pressed by air, whereby the left bellows contracts. In the bellows pump 150, since the left and right bellows are connected by, for example, a connecting rod, the bellows positioned on the right side expands as the left bellows contracts. Thereby, the chemical solution in the chemical solution tank flows into the bellows pump 150 (inside the right bellows) via the suction port 152. Next, the electromagnetic valve 130 in the device arrangement area 200 is switched, and the air taken in from the intake port 100 is supplied from the pipe 19 to the bellows pump 150 (the right side in FIG. 4) via the quick exhaust valve 162 and the pipe 23. The With the supply of air, the bellows provided on the right side in the bellows pump 150 is pressed with air, and the right bellows contracts accordingly. Furthermore, the bellows located on the left side expands as the bellows on the right side contracts. Thereby, the chemical solution in the chemical solution tank flows into the bellows pump 150 (in the left bellows) via the suction port 152, and the chemical solution flowing into the right bellows passes through the discharge port 154 to a predetermined liquid supply line ( (Not shown). The pump system 3 enables continuous supply of the chemical liquid by such expansion and contraction of the bellows pump 150 by switching the electromagnetic valve 130.

  In the pump system 3 shown in FIG. 4, the pressure of the chemical liquid discharged from the discharge port 154 of the bellows pump 150 changes with a constant period corresponding to the expansion and contraction of the bellows in the bellows pump 150.

FIG. 5 is a graph showing an example of a change in the discharge pressure (MPa) of the bellows pump in the pump system shown in FIG. As shown in FIG. 5, the discharge pressure of the bellows pump changes to a waveform shape having one cycle with one expansion / contraction of the right bellows or the left bellows of the bellows pump. Here, the waveform shown in FIG. 5 shows a relatively large pressure change per cycle. One of these pressure changes is that it has one large valley (pressure drop) D ₀ per cycle. Furthermore, this pressure change is a gradual drop in pressure appearing at the top of the waveform as shown in FIG. 5, which is expressed as a slope of ΔY ₀ / ΔX ₀ . The larger the trough (D ₀ ) per cycle and the absolute value of the slope (ΔY ₀ / ΔX ₀ ), the more the chemical solution is discharged from the discharge port 154 of the bellows pump with greater “pulsation”.

  In recent years, for example, in the field of semiconductor manufacturing, it has been pointed out that “pulsation” generated when such a chemical solution is supplied affects semiconductor manufacturing. For example, there are problems such as damage to equipment in the liquid piping due to piping vibration due to pulsation, and dust collected by the filter flowing out due to pump pulsation.

  In order to reduce pulsation, it is necessary to improve pressure drop and pressure trough. As for the depression, the air chamber around the bellows is constantly increasing while the bellows is being discharged, and as a result, the air pressure is lower than that at the time of setting. When the bellows starts to move (discharge), the air filling speed is faster than the bellows movement, but then the air is gradually delayed, resulting in a drop in pressure. On the other hand, since the pressure trough occurs when the left and right bellows discharge is switched, the trough becomes deep unless the discharge start on one side and the other side is started as soon as possible.

  In order to reduce the occurrence of such pulsation, conventionally, a pump system 4 in which an accumulator (pressure accumulator) 180 is connected to the downstream side (that is, the discharge port side) of the bellows pump is also widely used in this field. (FIG. 6). In the pump system 4 shown in FIG. 6, the chemical liquid is discharged from the discharge port 154 of the bellows pump 150 through the inflow port 182 of the accumulator 180 and through the discharge port 184 to a predetermined liquid supply line (not shown). The

Here, in the pump system 4 as shown in FIG. 6, the valley (D _A ) per cycle can be suppressed to, for example, a pulsation width of about 50% to 12.5% by the interposition of the accumulator 180. (D _A <D ₀ ) (FIG. 7). However, even in such a system 4, the absolute value of the inclination (ΔY _A / ΔX _A ) per cycle is not smaller than the absolute value of the inclination (ΔY ₀ / ΔX ₀ ), and is still A slight pulsation is observed in the chemical solution discharged from the discharge port 184 of the accumulator 180.

  An object of the present invention is to solve the above-mentioned problems. The purpose of the present invention is to change the discharge pressure of a chemical solution to be discharged in a pump system using a bellows pump. It is an object of the present invention to provide a pump system that improves both of them and enables further reduction of pulsation.

The present invention is a system for reducing pump pulsation comprising an equipment placement area and a liquid process line,
The equipment placement area includes an air inlet, an air regulator and a solenoid valve; and the air inlet, the air regulator and the solenoid valve communicate with each other to supply air sucked from the air inlet, and the liquid process line Is provided with a bellows pump, and communicates to supply air supplied from the solenoid valve into the bellows of the bellows pump,
Here, the system is provided with a buffer tank through which the air sucked from the intake port passes downstream of the air regulator.

  In one embodiment, the buffer tank is provided in the device arrangement area.

  In one embodiment, the buffer tank is provided downstream of the air regulator and upstream of the solenoid valve.

  In one embodiment, a quick exhaust valve communicating with the downstream of the solenoid valve and upstream of the bellows of the bellows pump so as to supply the air supplied from the solenoid valve into the bellows of the bellows pump. Is provided.

  In a further embodiment, the quick exhaust valve is provided in the liquid process system.

  In one embodiment, the chemical solution outlet of the bellows pump communicates with the accumulator.

  According to the present invention, it is possible to further reduce the pulsation of the discharged chemical liquid and supply the chemical liquid to a predetermined liquid supply line. The pump system of the present invention can reduce the occurrence of such pulsation by a simple improvement on the air supply line without requiring any complicated and expensive device.

It is a schematic diagram for demonstrating an example of the pump system of this invention. It is a schematic diagram for demonstrating the other example of the pump system of this invention. It is a graph which shows the change of the discharge pressure at the time of discharging a chemical | medical solution from a bellows pump using the pump system of this invention shown in FIG. 2, Comprising: (a) is this invention at the time of using a 0.78L buffer tank. It is a graph which shows the change of the said discharge pressure in the pump system of this; (b) is a graph which shows the change of the said discharge pressure in the pump system of this invention at the time of using a 1.45L buffer tank; (c) FIG. 4 is a graph showing a change in the discharge pressure in the pump system of the present invention when a 3.5 L buffer tank is used; FIG. 4D is a graph in the pump system of the present invention when a 5.8 L buffer tank is used. It is a graph which shows the change of the said discharge pressure; And (e) is the said discharge in the pump system of this invention at the time of using a 11.3L buffer tank. Is a graph showing the change in force. It is a schematic diagram for demonstrating the outline | summary of the conventional pump system using a bellows pump. It is a graph which shows an example of the change of the discharge pressure at the time of discharging a chemical | medical solution from a bellows pump using the conventional pump system shown in FIG. It is a schematic diagram for demonstrating the outline | summary of the other conventional pump system using a bellows pump. It is a graph which shows an example of the change of the discharge pressure at the time of discharging a chemical | medical solution from a bellows pump using the other conventional pump system shown in FIG.

  Hereinafter, the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic diagram for explaining an example of the pump system of the present invention.

  The pump system 1 of the present invention includes an equipment arrangement area 200 and a liquid process line 300.

  The device arrangement area 200 constituting the pump system 1 of the present invention includes an intake port 100, an air regulator 110, and an electromagnetic valve 130. The intake port 100 and the air regulator 110 are communicated with each other by a pipe 11, and the air sucked from the intake port 100 can be supplied to the air regulator 110 through the pipe 11. In the air regulator 110, a predetermined pressure adjustment is performed on the inflowing air, and the air can be supplied further downstream through a pipe described later.

  In the pump system 1 shown in FIG. 1, a buffer tank 120 is provided downstream of the air regulator 110. In the pump system 1 of the present invention, the buffer tank 120 is also provided in the device arrangement area 200. Further, in the pump system 1 shown in FIG. 1, the buffer tank 120 is provided downstream of the air regulator 110 and between the electromagnetic valve 130, between the air regulator 110 and the buffer tank 120, and between the buffer tank 120 and the electromagnetic valve 130. The valve 130 communicates with pipes 13 and 15, respectively. By having such a configuration, the air sucked from the intake port 100 can be supplied from the air regulator 110 to the electromagnetic valve 130 via the buffer tank 120.

  Here, the buffer tank 120 is provided with a space that is kept airtight with respect to the outside, except for the portions connected to the pipes 13 and 15. The buffer tank 120 is, for example, a box made of a material such as metal or plastic, and the volume of the box changes due to the inflow of air from the pipe 13 and the outflow of air to the pipe 15. No, that is, a form having no stretchability. Alternatively, the buffer tank 120 is made of a material whose inner volume is always kept constant regardless of the inflow of air from the pipe 13 and the outflow of air to the pipe 15.

  Examples of the metal that can constitute the buffer tank 120 include stainless steel and aluminum. Examples of the plastic that can constitute the buffer tank 120 include thermoplastic resins such as (for example, polypropylene, polyethylene, polystyrene, polycarbonate, poly (meth) acrylate, acrylonitrile, butadiene-styrene copolymer (ABS)); PTFE (polytetrafluoroethylene), PFA (tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer), FEP (tetrafluoroethylene / hexafluoropropylene copolymer), ETFE (tetrafluoroethylene / ethylene copolymer), PVDF (Polyvinylidene fluoride), PCTFE (polychlorotrifluoroethylene), ECTFE (chlorotrifluoroethylene / ethylene copolymer), and the like. Tank 120, or may be composed of these materials from the stack.

  As the internal volume of the buffer tank 120, one having a size suitable for those skilled in the art can be selected according to the pump capacity of the bellows pump to be used. For example, when the discharge amount of the bellows pump is 40 liters / minute, the internal volume of the buffer tank 120 is, for example, 0.7 liters to 12 liters, preferably 5 liters or more. That is, the internal volume of the buffer tank 120 is preferably about 1/10 or more of the discharge amount of the bellows pump.

  Next, the air supplied to the electromagnetic valve 130 via the pipe 15 is supplied to the liquid process line 300 provided downstream via the pipe 17 or 19 by switching the electromagnetic valve 130.

  In the pump system 1 of the present invention, the liquid process line 300 includes a bellows pump 150 and two quick exhaust valves 162 and 164. In FIG. 1, the pipe 17 communicates with the quick exhaust valve 164, and the pipe 19 communicates with the quick exhaust valve 162.

  The bellows pump 150 constituting the pump system 1 of the present invention is, for example, a bellows pump in which a suction port 152 and a discharge port 154 are arranged in the center and a pair of bellows is provided at both ends thereof. The size of the bellows pump that can be used in the pump system of the present invention is not particularly limited. In the pump system of the present invention, for example, a bellows pump having a discharge rate of 3 liters / minute to 150 liters / minute, preferably 5 liters / minute to 120 liters / minute can be used.

  In FIG. 1, the air supplied from the pipe 17 is supplied to the bellows pump 150 (left side in FIG. 1) via the quick exhaust valve 164 and the pipe 21. Along with the supply of air, the bellows provided on the left side in the bellows pump 150 is pressed by the supplied air, whereby the left bellows contracts. In the present invention, the bellows pump 150 has left and right bellows connected by, for example, a connecting rod. For this reason, the bellows located on the right side starts to expand as the left bellows contracts. As a result, the air around the bellows provided on the right side is discharged through the pipe 23 and the quick exhaust valve 162, and the chemical solution in the chemical solution tank passes through the suction port 152 in the bellows pump 150 (right bellows). In).

  Next, the electromagnetic valve 130 in the device arrangement area 200 is switched, and the air taken in from the intake port 100 is supplied from the pipe 19 to the bellows pump 150 (the right side in FIG. 1) via the quick exhaust valve 162 and the pipe 23. The With the supply of air, the bellows provided on the right side in the bellows pump 150 is pressed with air, and the right bellows contracts accordingly. Further, as the right bellows contracts, the bellows located on the left side starts to expand. Thereby, the air around the bellows provided on the left side is discharged through the pipe 21 and the quick exhaust valve 164, and the chemical in the chemical tank is in the bellows pump 150 (in the left bellows) through the suction port 152. In addition, the chemical liquid that has previously flowed into the right bellows is supplied to a predetermined liquid supply line (not shown) through the discharge port 154.

  Further, the electromagnetic valve 130 in the device arrangement area 200 is switched, and the air taken in from the intake port 100 is supplied from the pipe 17 to the bellows pump 150 (the left side in FIG. 1) via the quick exhaust valve 164 and the pipe 21. Is done. Along with the supply of air, the bellows provided on the left side in the bellows pump 150 is pressed by air, whereby the left bellows contracts. Further, as the left bellows contracts, the bellows located on the right side starts to expand. Thereby, the air around the bellows provided on the right side is discharged through the pipe 23 and the quick exhaust valve 162, and the chemical liquid in the chemical liquid tank is in the bellows pump 150 (in the right bellows) via the suction port 152. In addition, the chemical liquid that has previously flown into the left bellows as described above is supplied to a predetermined liquid supply line via the discharge port 154.

  The pump system 1 of the present invention enables continuous supply of a chemical solution by expanding and contracting the bellows in the bellows pump 150 by switching the electromagnetic valve 130 as described above. The air that has pressed the left and right bellows as the bellows in the bellows pump 150 contracts is discharged to the outside through the pipes 25 and 27 and the quick exhaust valves 162 and 164, respectively.

  The pump system 1 of the present invention can relieve the pressure change of the air passing through each pipe by the buffer tank 120 provided downstream of the air regulator 110 as described above. As a result, air to the bellows pump 150 provided in the liquid process line 300 can be supplied in a state in which the pressure change is further reduced, and the valley and inclination of the pressure change of the chemical solution per cycle accompanying the expansion and contraction of the bellows. Both can be improved and pulsation can be reduced.

  FIG. 2 is a schematic diagram for explaining another example of the pump system of the present invention.

  In the pump system 2 shown in FIG. 2, in order to reduce the occurrence of pulsation of the chemical liquid discharged from the bellows pump 150, an accumulator (accumulated pressure) is connected to the downstream side of the bellows pump 150 (that is, the discharge port 154 side) via a pipe 31. Except for the point that 180) is provided, the other configuration is the same as that of the pump system 1 of the present invention shown in FIG.

  In the pump system 2 of the present invention, the accumulator 180 temporarily stores the chemical liquid using the pressure of the chemical liquid discharged from the discharge port 154 of the bellows pump 150, and flows out the chemical liquid when the pump is switched to reduce the discharge pressure. This is a device that can further suppress the pressure drop of the discharged chemical. In FIG. 2, in the pump system 2, the chemical liquid is discharged from the discharge port 154 of the bellows pump 150 through the inflow port 182 of the accumulator 180 and through the discharge port 184 to a predetermined liquid supply line (not shown). .

  As described above, the pump system 2 of the present invention uses the buffer tank 120 provided downstream of the air regulator 110 and the accumulator 180 provided downstream of the bellows pump 150 to change the pressure of air passing through each pipe. The pressure change itself of the chemical solution discharged from the bellows pump 150 can be directly reduced. As a result, it is possible to further improve both the valley and inclination of the pressure change of the chemical solution per cycle accompanying the expansion and contraction of the bellows of the bellows pump 150 provided in the liquid process line 300, and further reduce the pulsation. .

  The pump system of the present invention can reduce the pulsation at the time of chemical solution supply that a conventional bellows pump can have. Thereby, for example, it can be used appropriately even in a situation where a high level of fluid transfer is required, such as the manufacture of semiconductors and liquid crystal display devices. Furthermore, for example, in the chemical engineering field, the present invention can be applied to fluid supply to a continuous chemical reaction using a CSTR (Continuous Stirred Tank Reactor) in which fluid pulsation is avoided.

  EXAMPLES Hereinafter, although an Example demonstrates this invention more concretely, this invention is not limited by these Examples.

(Example 1) Measurement of pulsation of bellows pump system (1) A bellows pump system shown in Fig. 2 was constructed using the apparatus described below. The internal capacity of the buffer tank was set to 0.78 liter.
・ Bellows pump (PE-40MA manufactured by Nippon Pillar Industries Co., Ltd.)
・ Accumulator (Nippon Pillar Industries Co., Ltd. (Part No.) PA-40HB)

  The pump system (1) configured as described above sucks water from a tank by connecting a pipe as a fluid instead of a chemical solution, and measures the pressure change of the fluid at the discharge port of the accumulator with a pressure transmitter type pressure gauge. . The obtained result is shown in FIG.

(Examples 2 to 5) Measurement of pulsation of bellows pump systems (2) to (5) The internal capacity of the buffer tank was changed to 1.45 liters, 3.5 liters, 5.8 liters or 11.3 liters. Except for this, bellows pump systems (2) to (5) were constructed in the same manner as in Example 1, and the change in pressure of the fluid at the discharge port of the accumulator was measured. The obtained results are shown in (b) to (e) of FIG.

As shown in FIGS. 3 (a) to 3 (e), a graph obtained by a conventional pump system as shown in FIG. 5 (a system without an accumulator) or a conventional pump system as shown in FIG. It can be seen that the valleys in the waveform per period are significantly shorter than the valleys (D ₀ and D _A ) shown in the graph obtained with the system with the accumulator. In addition, the pressure drop that appears at the top of the waveform per cycle is also gradual. Compared to the absolute values of the slopes (ΔY ₀ / ΔX ₀ and ΔY _A / ΔX _A ) shown in FIG. 5 and FIG. It can be seen that the absolute value is even smaller. Thereby, it turns out that the pulsation is remarkably reduced in the chemical liquid discharged from the discharge port 154 of the bellows pump 150 in the pump systems (1) to (5) of the present invention.

  The pump system of the present invention is useful for transferring a desired fluid, for example, supplying a high-purity chemical solution in manufacturing a semiconductor or a liquid crystal display device, or metering injecting a pharmaceutical product.

DESCRIPTION OF SYMBOLS 1, 2 Pump system 100 Inlet port 110 Air regulator 120 Buffer tank 130 Solenoid valve 150 Bellows pump 152 Inlet port 154 Outlet port 162,164 Quick exhaust valve 180 Accumulator 200 Equipment arrangement area 300 Liquid process line

Claims (6)

A system for reducing pump pulsation comprising an equipment placement area and a liquid process line for supplying a chemical liquid to a liquid supply line ,
The equipment placement area includes an air inlet, an air regulator and a solenoid valve; and the air inlet, the air regulator and the solenoid valve communicate with each other to supply air sucked from the air inlet, and the liquid process line the 1 but with the bellows pump comprising a pair of bellows at both ends, and through switching of the solenoid valve, by supplying air sucked from the intake port to alternately around the bellows of said pair of said bellows pump Communicating so that the pair of bellows can be pressed alternately ,
Here, a buffer tank air sucked from the intake port downstream of the air regulator to pass, and the buffer tank that provided upstream of the bellows pump, system.   The system according to claim 1, wherein the buffer tank is provided in the device arrangement area.   The system according to claim 1, wherein the buffer tank is provided downstream of the air regulator and upstream of the solenoid valve.   A quick exhaust valve is provided downstream of the solenoid valve and upstream of the bellows of the bellows pump so as to communicate the air supplied from the solenoid valve into the bellows of the bellows pump. Item 4. The system according to any one of Items 1 to 3. The system of claim 4, wherein the quick exhaust valve is provided in the liquid process line .   The system according to claim 1, wherein the chemical liquid discharge port of the bellows pump communicates with an accumulator.

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