JPH0683975U - Check valve of oilless compressor controlled by pressure switch - Google Patents

Abstract

(57) [Abstract] [Purpose] To obtain a non-return valve with a good seating property, which is connected to the discharge side of a pressure switch-controlled oilless compressor. [Structure] A fluororubber ball valve that sits on and separates from the tapered seat surface is provided, the spring is not provided, and the valve body is seated on the seat surface only by the back pressure flow. The seat can be operated well both vertically and horizontally. Also, noise generated when the valve body is seated on the seat surface has been eliminated.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present application relates to a check valve of a pressure switch-controlled oilless compressor, which is used by being connected to a discharge side of an oilless compressor body.

[0002]

[Prior art]

 As a compressor operation control method, when the discharge pressure, for example, the pressure of the air tank reaches the specified upper limit pressure, the pressure switch that detects the discharge pressure operates and shuts off the current to the motor that drives the compressor. Then, when the compressed air is used and the discharge pressure reaches the specified lower limit pressure, the pressure switch detects again and supplies the current to the motor that drives the compressor. There is a pressure switch control to restart the compressor. The pressure switch control has the highest energy-saving effect and is widely used as compared with unloader operation control in which no load (non-compression) operation is performed when the upper limit pressure is reached. In the pressure open / close control, when restarting after stopping, in order to reduce the starting load of the motor, discharge air is released to the atmosphere and the discharge side is released to the atmosphere at each stop. In a compressor set that supplies compressed air from the compressor body to the air tank via a connecting pipe, the amount of compressed air released to the atmosphere is the amount of compressed air that has once accumulated in the air tank of the discharge piping system. Since exhausting is very wasteful, a check valve (compressed air from the compressor body side to the air tank side normally passes between the discharge pipe of the compressor body and the air tank A valve that has the function of not passing from the tank side to the compressor side is installed.

In the case of an oil-free reciprocating compressor, the means for releasing to the atmosphere is to connect the inlet of the release pipe to a position between the valve body and the connecting pipe in the check valve, and connect the release pipe to the release pipe. The outlet is connected to a release valve that works in conjunction with the pressure switch.When the pressure switch detects the upper limit pressure, the compressor stops, the release valve opens, and the check valve valve body opens. The compressed air in the connecting pipe and the compressed air remaining in the cylinder chamber are released to the atmosphere from the release valve through the release pipe. Also, in the case of an oil-free scroll compressor, a check valve is also attached to the discharge side of the scroll compressor body and then connected to the air tank. However, compressed air remains between the valve body of the check valve and the main body of the oil-free scroll compressor at the moment when the pressure switch stops working. Since the pressure applied to the discharge center of the fixed / orbiting scroll is higher than that of the compression chamber toward the outer periphery, the pressure applied to the discharge center causes the orbiting scroll to move in the opposite direction to that during compression operation. The force to rotate it works.

Therefore, with this reverse rotation, the compressed air remaining between the check valve and the main body of the oil-free scroll compressor flows from the central portion toward the outer peripheral portion, and is connected to the outer peripheral portion by the suction filter. It is supposed to be released into the atmosphere from. In this way, in the case of the oilless compressor, the one that performs pressure switch control as operation control controls the discharge pressure between the check valve and the oilless compressor every time the pressure switch operates and stops. When the air is released into the atmosphere and restarted, the load on the motor is reduced, so the motor can rotate smoothly without humming.

[0005]

[Problems to be solved by the device]

 The non-return valve connected to the discharge side of these oil-free compressors causes backflow from the air tank when leakage occurs at the time of stop, and even the compressed air in the air tank is released to the atmosphere. Even if the compressed air in the air tank is not used at all, the pressure in the air tank drops, the oilless compressor enters the operating state again, the running cost rises, and the durability decreases due to the extension of the operating time. Was also forced to. Here, in the case of a refueling type compressor, a small amount of lubricating oil is also contained in the discharge air, so this lubricating oil will form an oil film between the valve body and valve seat of the check valve to prevent leakage. However, in the case of a compressor without oil supply, that is, in a system in which no lubricating oil is supplied to the compression chambers of the cylinder chamber and scroll chamber, the reverse connection used on the discharge side of the compressor is used. No oil film can be formed on the valve seat portion of the stop valve, and how to prevent the leakage of the valve seat portion has been a major issue.

Further, in the case of a valve body in which a fixed portion is always in contact with the seat portion of the valve body to the valve seat portion, uneven wear of the valve body occurs, causing a problem of short-term seat leakage. It was Further, when the valve body of the check valve is made of metal, there is a problem that a metallic sound is generated each time the seat is seated. When the valve body in the check valve is a metal ball and has a heavy mass, the check valve generally had to be mounted vertically, and the set could not be mounted freely.

[0007]

[Means for Solving the Problems]

 Therefore, the present proposal was made to solve these problems, and in a check valve that is connected to the discharge side of the oil-free compressor body and is constructed by detachably attaching the body and the cap to each other. The flow path formed in the main body includes an introduction port, a tapered valve seat surface continuous with the introduction port, the tapered valve seat surface, and the maximum opening of the tapered valve seat surface. In the flow passage formed in the cap, an inlet passage is opened on the side of the main body facing the outlet, and an outlet passage is formed continuously with the inlet passage. In addition, when compressed air flows from the main body side to the cap side in the flow path integrated with the main body and the cap, the compressed air separates from the tapered valve seat surface and compressed air is generated. , From the cap side A ball valve that sits on the tapered valve seat surface when flowing toward the body side, and the ball valve is formed of a fluorine-based heat-resistant rubber material, and the ball valve and the tapered valve seat surface described above are used. It is a check valve for an oil-free compressor, which is characterized in that it is provided with a valve support that regulates the opening degree of the.

[0008]

[Action]

 When the oil-free compressor is stopped, the pressure switch operates, and when the motor that drives the compressor is stopped, the check valve installed on the discharge side of the compressor operates from the compressor body to the air tank. The flow of compressed air to the side of the valve stops, and the compressed air between the check valve and the compressor body is discharged to the atmosphere, so that the ball valve that was separated from the valve seat will flow backward from the air tank side. By virtue of the vigorous compressed air, it is pressed against the tapered valve seat side and a reliable seat can be performed. Since this ball valve is spherical, it can rotate, so that the seat portion toward the valve seat side does not always become a constant part, the seating property is good, and no sound is generated when the ball valve seats. . Furthermore, it is heat-resistant and does not distort due to heat even when it comes into contact with hot compressed air. Even if the check valve is oil-free and non-lubricated, good seatability can be maintained for a long period of time.

[0009]

【Example】

 An example of the present invention will be described in detail below. FIG. 1 shows a state in which the check valve 5 of the present invention is connected to the discharge sides 11 and 21 of the oil-free scroll compressor bodies 1 and 2, and the outlet 42 of the check valve 5 is air-cooled. An air tank 9 is connected to the outlet of the air cooler 8.

In FIG. 1, two oil-free scroll compressor bodies 1 and 2 are set, and two motors (not shown) are set to drive the respective body 1 and 2. In this compressor set, depending on the amount of compressed air used, when the amount is large, both main units 1 and 2 are in compression operation, and when the amount is small, only one of main unit 1 or 2 is operating, and when not in use. Has a tandem control in which both the main units 1 and 2 are stopped. Here, in the tandem control, the two main bodies 1 and 2 are periodically replaced and operated, so the problem that only one main body is operated for a long time and the other main body is hardly operated is solved. There is. The check valve 5 used here is, as shown in FIG. 2, an inlet 31 in the main body 3, a tapered valve seat surface 32 continuous to the inlet 31, and a maximum of the valve seat surface 32. It is composed of a flow path formed of a lead-out port 34 continuous with the opening 33, and a cap 4 is detachably attached integrally to the side of the main body facing the lead-out port 34 with a bolt or a screw.

The flow passage formed in the cap 4 has an inlet passage 41 opened on the side facing the outlet 34 of the main body 3, and an outlet passage 42 is formed continuously with the inlet passage 41. In addition, when compressed air flows from the main body 3 side to the cap 4 side in the flow path integrated by the main body 3 and the cap 4, it separates from the tapered valve seat surface 32. When the compressed air tries to flow backward from the cap 4 side to the main body 3 side, a ball valve 6 is attached to the tapered valve seat surface 32 so as to be in close contact with the flow of the flow. The valve 6 and the valve seat 7 that regulates the opening of the tapered sheet surface 32 are provided. A flow path communicating with the valve support 7 is formed. The ball valve 6 is not made of steel balls but is made of fluorine-based heat-resistant rubber balls. The non-return valve in Fig. 2 shows the example installed laterally. The ball valve drawn by the one-dot chain line indicates that the compressed air is not flowing or the compressed air flows from the main body 3 side to the cap 4 side. A state where the compressed air that flows backward from the cap 4 side to the main body 3 side is stopped is shown in the ball valve drawn by the solid line.

Since the check valve of the oil-free compressor of the present invention has the above-described configuration, the pressure in the discharge piping system, for example, the air tank 9 or the discharge piping 10 has a specified upper limit. When the pressure is reached, the pressure switch 11 attached to the discharge piping system works to shut off the current flowing to the motors that drive the oilless compressor bodies 1 and 2, and the oilless compressor bodies 1 and 2 are cut off. Both units stop the compression operation. Here, the compressed air in the oil-free compressor bodies 1 and 2 flows backward through a release valve (not shown) in the case of a reciprocating compressor and to the suction side in the case of a scroll compressor, Each is released into the atmosphere. At the same time, the check valves 5 and 51 both seat the ball valve 6 on the tapered valve seat surface 32 only by the back pressure from the outlet passage 42. Since the ball valve 6 is formed of a fluorine-based heat-resistant rubber ball, it can be brought into close contact with the tapered valve seat surface due to its light weight and elasticity. Therefore, the compressed air in the discharge piping system is retained and the compressed air in the compressor body is released to the atmosphere, so that the load on the motor can be reduced at the time of restart.

In addition, in the scroll compressor, the start-up is performed with a delay of several seconds without starting the two compressors at the same time, so that the start-up current consumption at the time of start-up can be reduced. Has become. Here, when the air consumption decreases, one compressor body 1 is stopped and only the other compressor body 2 is in compression operation. However, when the check valve 51 leaks, the air compressed in the compressor body 2 flows backward from the check valve 51 and causes the orbiting scroll (not shown) to rotate in the compressor body 2 in the reverse direction. While flowing toward the suction side, it is released to the atmosphere through the suction port. Therefore, the flow from the compressor body 2 to the check valve 5, the air cooler 8, and the air tank 9 is reduced, and the pressure of the discharge piping system 10 is reduced without using compressed air, and the lower limit of the pressure switch is reached. The compressor main body 1 which has been stopped due to the pressure is started and the driving power is wasted. However, the waste caused by the leakage due to the check valve of the oil-free compressor is the opposite of that of the present proposal. The stop valve is a rubber ball, has a lighter specific gravity than a metal ball, and can be brought into close contact with the tapered seat surface only by the back pressure flow, so it can be achieved without limiting the mounting direction.

[0014]

[Effect of device]

 A non-return valve that is used by being connected to the discharge piping system of an oil-free compressor, and the valve is a ball valve, the valve seat surface of the ball valve is a tapered surface, and the tapered valve seat surface is Since the ball valve that sits and separates is made of a fluorine-based heat-resistant rubber ball, it can withstand the high temperature of compressed air, and because of the rubber ball, the mass can be lightened and the elastic force of the rubber The seating property on the tapered valve seat surface is improved. In addition, since the ball valve moves while rotating in the passage in the check valve, a certain part of the rubber ball does not always sit on the tapered valve seat surface, and due to the elasticity of the rubber ball, the seat does not move. In addition, even if the ball valve becomes slightly spherical due to heat, the valve seat surface of the other valve is tapered, so that the seat can be favorably maintained for a long period of time.

When the ball valve is pressed by a spring, the pressing force is strong and the ball valve and the valve seat surface are easily damaged, but since the check valve of the present invention does not use a spring, the ball valve, etc. Does not hurt. Furthermore, since the ball valve is made of fluorine-based rubber, it is possible to prevent metallic noise that is generated each time the ball valve is seated on the seat surface, so a quiet operation oilless compressor is possible. can get. In addition, since the rubber ball valve has a light mass, it is configured to sit on the seat surface only with back pressure flow, so the check valve can be installed in any direction, including up, down, left, and right. , It is possible to freely attach the orientation according to the mounting of the set.

[Brief description of drawings]

FIG. 1 is an explanatory diagram in which a check valve of the present invention is connected to a discharge piping system of an oilless compressor.

FIG. 2 is a vertical sectional view of the check valve of the present invention.

[Explanation of symbols]

 3 Body 4 Cap 5, 51 Check valve 6 Ball valve 32 Tapered seat surface

Claims (1)

[Scope of utility model registration request] 1. A non-return valve (5) connected to the discharge side of an oilless compressor body, comprising a body (3) and a cap (4) detachably attached to the body, the body (3) ), The flow path formed in the inlet port (31) and the tapered valve seat surface (32) continuous with the inlet port (31).
And a tapered valve seat surface (32) and an outlet (34) continuous with the maximum opening (33) of the tapered valve seat surface (32), and the cap (4) ), An inlet passage (41) is opened on the side facing the outlet (34) of the main body (3), and an outlet passage (42) is formed continuously with the inlet passage (41). In addition, when the compressed air flows from the main body (3) side to the cap (4) side in the flow path integrated with the main body (3) and the cap (4), the tapered shape is formed. Of the valve seat surface (32) of (1), and when compressed air flows from the side of the cap (4) to the side of the body (3), the ball valve (which sits on the tapered valve seat surface (32) ( 6) and that the ball valve (6) is molded from a fluorine-based heat-resistant rubber material. And a valve support (7) for restricting the opening of the ball valve (6) and the tapered valve seat surface (32). Check valve of a rotary compressor.