JPH04116274A - High-pressure pump - Google Patents

Abstract

PURPOSE:To obtain a compact high-pressure pump preventing the pollution of a high-pressure seal by providing an operating air port on one side of an air piston in the reciprocating high-pressure pump having the air piston, a plunger and a water cylinder. CONSTITUTION:When the operating air (a) is guided to an operating air port 5 in the discharge stroke, an air piston 4 is moved to the left, and the air in a space (g) between it and an air flange 15 is exhausted to the outside through an air vent hole 22. A high-voltage seal 11 seals the discharge pressure, a discharge liquid is slightly leaked to an air cylinder 3 side, it is discharged to the outside through the air vent hole 22 together with a leakage drain 21 and the exhaust air, and the infiltration of the liquid into the air cylinder 3 is prevented. Negative pressure is applied to the operating air port 5 in the intake stroke, the air piston 4 is moved to the right, and air is guided to the space (g) via the air vent hole 22. The high-pressure seal 11 seals the intake line pressure, the liquid is rarely leaked, thus the infiltration of the liquid into the air cylinder 3 is prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a high-pressure pump that pressurizes liquid sucked in from a suction port and discharges it from a discharge port, and in particular, the present invention relates to a high-pressure pump that is suitably used as a jet scrubber in semiconductor manufacturing equipment. Regarding.

[Prior Art] FIG. 5 shows an example of a conventional high-pressure pump. In the high-pressure pump, which is generally designated by the symbol IA, a plunger 2 compresses a pump chamber C with working air and discharges liquid within the pump chamber C.

The air piston 4 housed in the air cylinder 3 slides to the left in the figure by the working air a supplied from the working air port 5, and by the working air b supplied from the working air port 6.
It slides to the right. As the air piston 4 slides left and right, the plunger 2 directly connected to the air piston 4 also slides left and right inside the water cylinder 7A.

When the plunger 2 attempts to move leftward due to the working air a being supplied from the working air port 5, the volume of the pump chamber C defined by the water cylinder 7A and the water cylinder head 8 is reduced. At this time, the liquid in the pump chamber C is pressurized to a pressure equal to the ratio of the areas of the air piston 4 and the plunger 2 multiplied by the pressure of the working air a.

When the pressure of the liquid in the pump chamber C increases, the suction side check valve 9 closes, the discharge side check valve 1o opens, and the pump chamber C
The liquid comes to be discharged from the discharge port e. At this time, when the valve of the discharge line is opened, the inside of the pump chamber C is continuously reduced by the amount of liquid that the injection nozzle of the discharge line passes at that pressure, and only discharge is performed. Here, in order to prevent the liquid in the pump chamber C from leaking, a high pressure seal 11 is interposed between the inner surface of the water cylinder 7A and the plunger 2.

On the other hand, in the suction stroke, working air b is supplied from the working air port 6, and the plunger 2 moves rightward. Then, the suction side check valve 9 opens, and the discharge side check valve 1 opens.
0 is closed, liquid is sucked into the pump chamber C through the suction port d, and a suction stroke is performed.

By repeating this operation, the high pressure pump IA
The pump increases the pressure of the low-pressure suction liquid to a predetermined pressure and discharges it. Note that FIG. 5 shows a standby state in which the air piston 4 is in contact with the air flange 12 at the right end and is waiting for a discharge command from a control means (not shown).

[Problems to be Solved by the Invention] However, in the above-described high-pressure pump IA, the working air b must be supplied to the working air port 6 when performing the suction stroke. In the past, the mouth seal 13 interposed between the plunger 2 and the air cylinder 3 was indispensable. This rod seal 13 is lubricated with grease for sliding movement with the plunger 2.

As a result, grease adheres to a portion of the plunger 2, which should be clean. Then, install the rod seal 1 so that the greased part does not reach the high pressure seal 11.
3 and the high pressure seal 11 must be longer than the stroke length of the plunger 2.

In contrast, a high-pressure pump IB shown in FIG. 6, which does not require the rod seal 13, has been proposed.

This pump IB performs a suction stroke by extending a return spring 14 provided in the air cylinder 3B, and the other operations are the same as in FIG. 5. However, since a space is required to provide the return spring 14 within the air cylinder 3B, the high-pressure pump IB itself cannot be made compact.

Nowadays, there is a demand for high-pressure pumps with a large displacement amount (discharge amount per pump) in order to clean the discharged fluid. However, increasing the displacement inevitably increases the size of the pump, which goes against the trend of downsizing equipment.

The present invention has been made in view of the problems of the prior art described above, and an object of the present invention is to provide a compact high-pressure pump that prevents contamination of the high-pressure seal.

[Means for Solving the Problems] According to the present invention, a reciprocating device includes an air piston that slides inside an air cylinder, a plunger that is directly connected to the air piston, and a water cylinder that forms a pump chamber inside. In a dynamic high pressure pump, an operating air port is provided on one side of the air piston.

The operating air port is preferably provided on the side of the air piston facing the plunger, that is, on the side where the air piston is moved during the discharge stroke.

In addition, a bearing is provided on the air cylinder side of the water cylinder to support the plunger, and a leak drain is formed.
It is preferable to form an air vent hole that also serves as a leak drain in the air flange.

Preferably, the actuation air port is configured to be selectively connected to a source of actuation air, a vacuum boat of the vacuum ejector, via a solenoid valve.

[Operation] In the high-pressure pump configured as described above, during the discharge stroke, the solenoid valve is switched to connect the working air source to the working air port. Then, the piston moves to the pump side, and the plunger compresses the pump chamber and discharges. At this time, air in the space between the air piston and the air flange is discharged from the air vent hole. At this time, the high pressure seal seals the discharge pressure, and although a small amount of discharged liquid leaks from the high pressure seal to the air cylinder side, it is discharged to the outside from the leak drain and air vent hole, and there is no risk of it entering the cylinder.

During the suction stroke, the solenoid valve is switched to connect the vacuum boat of the vacuum ejector to the working air port, and to connect the working air source to the pressure boat of the vacuum ejector. This causes negative pressure to act on the operating air port, causing the air piston to return.
Move the plunger in the opposite direction to perform suction.

At this time, air is introduced into the space between the air piston and the air flange through the air vent hole. At this time, the high pressure seal seals the suction line pressure (low pressure), and almost no liquid leaks from the high pressure seal in this state, so there is no risk of liquid entering the air cylinder.

[Example] The present invention will be described in detail below with reference to the drawings.

Note that in FIG. 1, parts corresponding to those in FIG. 5 are given the same reference numerals and redundant explanation will be omitted.

In FIG. 1, the air cylinder 3 of the water cylinder 7
A bearing 20 on which the plunger 2 slides is provided on the side. The bearing 20 is made of synthetic resin such as high-density polyethylene, and also serves as a backup ring for the high-pressure seal 11, and has a one-sided clearance f with the plunger 2 of, for example, about 30 μm. The bearing 20 is
It is designed to be lubricated by liquid leaking from the high-pressure seal 11, and a leak drain 21 is formed in the middle of the bearing 20 to drain the leaked liquid.

Further, the air flange 15 is formed with an air vent hole 22 that also serves as a leak drain for releasing air in the space g between the air piston 4 and the air flange 15 to the outside.

2 to 4 show working air circuit diagrams for operating the high-pressure pump 1. As shown in FIGS.

FIG. 2 shows the state of the high-pressure pump 1 during its discharge stroke.

The working air port 5 is connected to a working air source 24 via a three-position exhaust center type solenoid valve 23 by an air circuit, and a discharge stroke is performed.

In addition, the code|symbol 25 in a figure is a vacuum ejector, and 26 is a silencer.

FIG. 3 shows the state of the high-pressure pump during the suction stroke. The working air is supplied to the working air source 2 via the switched solenoid valve 23.
4 to the pressure boat P of the vacuum ejector 25 by an air circuit L1. The operating air port 5 of the high-pressure pump 1 is connected to the vacuum boat (■) of the vacuum ejector 25 by an air circuit L2 via a solenoid valve 23. Therefore, the inside of the air cylinder 3 becomes negative pressure, and the air piston 4 returns. A suction stroke is performed.

FIG. 4 shows the high-pressure pump 1 in a standby state.

Working air is blocked by a switched solenoid valve 23;
No action is taken. Since working air does not act on the pressure boat P of the vacuum ejector 25, the vacuum boat V is at atmospheric pressure. The operating air port 5 of the high-pressure pump 1 is connected to the vacuum boat V of the vacuum ejector 25 by an air circuit L2 via a switched solenoid valve 23. Therefore, the inside of the air cylinder 3 becomes atmospheric pressure, and the air piston 4 becomes stationary and in a standby state.

Next, the operation will be explained with reference to FIG.

In the discharge stroke, when the working air a is guided to the working air port 5, the air piston 4 moves to the left, and the air in the space g between the air piston 4 and the air flange 15 is exhausted to the outside from the air vent hole 22. Ru.

At this time, the high pressure seal 11 seals the discharge pressure, and a small amount of discharged liquid leaks from the high pressure seal 11 to the air cylinder 3 side, but it is discharged to the outside from the air vent hole 22 together with the leak drain 21 and the exhausted air. There is no risk of liquid entering the air cylinder 3.

During the suction stroke, negative pressure is applied to the operating air port 5,
The air piston 4 moves to the right, and air is introduced into the space g through the air vent hole 22. At this time, the high-pressure seal 11 seals the suction line pressure (low pressure), and liquid hardly leaks from the high-pressure seal 11 in this state, so there is no risk of liquid entering the air cylinder 3. That's not it.

[Effects of the Invention] Since the present invention is configured as described above, it is possible to prevent contamination of conventional high-pressure seals with grease.

Therefore, there is no need to lengthen the plunger, and as a result, the high-pressure pump can be made more compact.

Furthermore, by lengthening the space between the air piston and the air flange and the pump chamber, the displacement of the high-pressure pump can be increased.

[Brief explanation of drawings]

FIG. 1 is a side sectional view showing an embodiment of the present invention; FIGS. 2, 3, and 4 are drawings showing the discharge stroke state, suction stroke state, and extended state of the working air circuit, respectively; FIGS. 5 and 6 are side sectional views showing different conventional high-pressure pumps, respectively. 1...High pressure pump 2...Plunger 3...Air cylinder 4...Air piston 5...Working air port 7...Water cylinder diagram! Diagram

Claims (1)

[Claims] A reciprocating high-pressure pump comprising an air piston that slides inside the air cylinder, a plunger directly connected to the air piston, and a water cylinder that forms a pump chamber inside, the air piston having an operating air port on one side. A high-pressure pump characterized by the following: