JP2022032735A - Multi-stage air compressor - Google Patents

Abstract

To provide a multi-stage air compressor which continues operating without stopping operation even when an intermediate pressure of the multi-stage air compressor becomes a predetermined value or more.SOLUTION: In a multi-stage air compressor, air passages of a low pressure stage compressor body and a high pressure stage compressor body are connected in series, and the low pressure stage compressor body and the high pressure stage compressor body are pipe-connected by first air piping. The multi-stage air compressor comprises a pressure detector connected in the middle of the first air piping, first air release piping branched from the middle of the first air piping, a first air release solenoid valve provided in the first air release piping, and a control device which is inputted with a pressure value detected by pressure detector and controls the first air release solenoid valve. When the pressure detected by the pressure detector becomes a predetermined pressure or more, the control device issues an open command to the first air release solenoid valve to control the first air release solenoid valve so as to discharge a part of compressed air compressed by the low pressure stage compressor body to the outside air.SELECTED DRAWING: Figure 1

Description

The present invention relates to a multi-stage air compressor and relates to prevention of operation stop when the intermediate pressure of the compressor exceeds a predetermined value.

As an air compressor that sucks in air and generates compressed air, a so-called multi-stage compressor that connects the air paths of a plurality of compressor bodies in series is known (hereinafter referred to as "multi-stage air compressor"). In a multi-stage air compressor, the air discharge side of the low-pressure stage compressor body and the air suction side of the high-pressure stage compressor body are connected via an intercooler, and compression is performed in two stages. be. In the multi-stage air compressor, the operation of the compressor is stopped when the intermediate pressure exceeds a predetermined value due to a decrease in the suction capacity of the high-pressure stage compressor body. The reason for stopping the operation of the compressor is to protect machines such as the rotor and bearings of the compressor body, avoid danger, and prevent a decrease in compression efficiency.

Patent Document 1 is a prior art document in the present technical field. Patent Document 1 is described for the purpose of providing a compressor capable of maintaining a discharge pressure in a desired pressure range without lowering the compression efficiency with respect to load fluctuations. However, the description does not take into consideration the case where the intermediate pressure and the discharge temperature of the multi-stage compressor are equal to or higher than the predetermined values. Further, if the discharge pressure is maintained by simply reducing the rotation speed of the motor, the intermediate pressure rises because the compression operation continues, and the intermediate pressure does not fall below the predetermined value.

Japanese Unexamined Patent Publication No. 2006-283649

An object of the present invention is to provide a multi-stage air compressor in which the compressor continues to operate without stopping the operation even when the intermediate pressure of the multi-stage air compressor exceeds a predetermined value.

The present invention is, for example, a multi-stage air compressor in which the air paths of the low-pressure stage compressor main body and the high-pressure stage compressor main body are connected in series, and the low-pressure stage compressor main body and the high-pressure stage compressor main body are A pressure detector connected by a first air pipe and connected in the middle of the first air pipe, a first air discharge pipe branching from the middle of the first air pipe, and a first release. It has a first air release electromagnetic valve provided in the air pipe and a control device for controlling the first air release electromagnetic valve to which the pressure value detected by the pressure detector is input, and the control device is a pressure detector. When the detected pressure becomes equal to or higher than a predetermined value, an opening command is issued to the first air release electromagnetic valve, and a part of the compressed air compressed by the low pressure stage compressor main body is controlled to be discharged to the outside air.

According to the present invention, even when the intermediate pressure of the multi-stage air compressor becomes a predetermined value or more, the compressor can continue the operation without stopping the operation.

It is a system diagram of the multistage air compressor in Example 1. It is a correspondence table of the set upper limit pressure and the valve opening degree in Example 2. It is a system diagram of the multistage air compressor in Example 3. It is a system diagram of the multistage air compressor in Example 4.

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

In this embodiment, an example in which the oil-free screw compressor main body has a two-stage configuration as a multi-stage air compressor will be described.

FIG. 1 is a system diagram of a multi-stage air compressor in this embodiment. In FIG. 1, the multi-stage air compressor 100 has a low-pressure stage compressor main body 101 and a high-pressure stage compressor main body 102.

A filter 103 for filtering ambient air and supplying it to the low-pressure stage compressor main body 101 is attached to the suction flow path of the low-pressure stage compressor main body 101, and a suction port 103A is provided on the downstream side of the filter 103. It is formed.

An intercooler 104 is provided between the discharge side of the low-pressure stage compressor main body 101 and the suction side of the high-pressure stage compressor main body 102, and the intercooler 104 is an air pipe 105 with the low-pressure stage compressor main body 101. The compressor is connected to the high-pressure compressor main body 102 by an air pipe 106. A pressure detector 118 for measuring the pressure of the compressor discharged from the low pressure stage compressor main body 101 is attached in the middle of the air pipe 106. The pressure value detected by the pressure detector 118 is input to the control device 119.

An aftercooler 108 is connected to the downstream of the high-pressure stage compressor main body 102 by an air pipe 109 via a check valve 107.

The first low-pressure stage degassing pipe 110 and the second low-pressure stage degassing pipe 111 are branched from the middle of the air pipe 105 connecting the low-pressure stage compressor main body 101 and the intercooler 104, respectively. The first low-pressure stage degassing pipe 110 is provided with the first low-pressure stage degassing two-way valve 112, and the second low-pressure stage degassing pipe 111 is provided with the second low-pressure stage degassing two-way valve 113. Has been done.

Similarly, from the upstream side of the check valve 107 in the middle of the air pipe 109 connecting the high-pressure stage compressor main body 102 and the aftercooler 108, the first high-pressure stage air exhaust pipe 114 and the second high-pressure stage discharge pipe 114. The air pipe 115 is branched. The first high-pressure stage degassing pipe 114 is provided with the first high-pressure stage degassing two-way valve 116, and the second high-pressure stage degassing pipe 115 is provided with the second high-pressure stage degassing two-way valve 117. Has been done.

The first low-pressure stage degassing two-way valve 112 and the first high-pressure stage degassing two-way valve 116 are air-discharging solenoid valves in which the low-pressure stage compressor main body 101 and the high-pressure stage compressor main body 102 operate during normal operation. Is. On the other hand, the second low-pressure stage degassing two-way valve 113 and the second high-pressure stage degassing two-way valve 117 do not operate during the operation of the multi-stage air compressor 100, and the power source of the multi-stage air compressor 100 is used. It is an air release solenoid valve that operates when the compressor is cut off, and is provided by the low pressure stage compressor main body 101 and the high pressure stage compressor main body 102 to prevent the compressed air from flowing back and being damaged. It is a valve. The first low-pressure stage degassing two-way valve 112, the first high-pressure stage degassing two-way valve 116, the second low-pressure stage degassing two-way valve 113, and the second high-pressure stage degassing two-way valve 117 is controlled by the control device 119.

Further, in order to supply the compressed air cooled by the aftercooler 108 to the user side, the discharge air pipe 120 is provided downstream of the aftercooler 108. A pressure detector 121 for measuring the pressure of the compressed air discharged from the multi-stage air compressor 100 is attached in the middle of the discharged air pipe 120. The pressure value detected by the pressure detector 121 is input to the control device 119.

The operation of the multi-stage air compressor in this embodiment configured in this way will be described below. When the multi-stage air compressor 100 is operated, a pair of rotors each of the low-pressure stage compressor main body 101 and the high-pressure stage compressor main body 102 rotate to compress air as a working gas. The ambient air for compression sucked from the suction port 103A is compressed by the low-pressure stage compressor main body 101, and the pressure rises and the temperature rises.

The high-temperature compressed air compressed by the low-pressure stage compressor main body 101 is guided to the intercooler 104 via the air pipe 105 and cooled by the intercooler 104. The compressed air cooled by the intercooler 104 is guided to the high-pressure stage compressor main body 102 via the air pipe 106, and is further boosted to a predetermined discharge pressure and the temperature rises.

The compressed air that has been boosted by the high-pressure stage compressor main body 102 and whose temperature has risen is guided to the aftercooler 108 via the air pipe 109, cooled by the aftercooler 108, and then supplied to the user side from the discharge air pipe 120. In this case, the control device 119 includes a first low-pressure stage degassing two-way valve 112, a second low-pressure stage degassing two-way valve 113, a first high-pressure stage degassing two-way valve 116, and a second high-pressure stage degassing. The air two-way valve 117 is controlled to be closed.

Subsequently, during no-load operation in which the compressed air consumption on the user side is reduced and it is no longer necessary to supply the compressed air to the user side, the control device 119 opens the first low-pressure stage degassing two-way valve 112 to open the compressed air. Is controlled to be open to the atmosphere. At this time, the control device 119 controls the second low-pressure stage degassing two-way valve 113, the first high-pressure stage degassing two-way valve 116, and the second high-pressure stage degassing two-way valve 117 in a closed state. do.

Further, as in the case of no-load operation, when the multi-stage air compressor 100 starts operation, the control device 119 controls to open the first low-pressure stage degassing two-way valve 112 to open the compressed air to the atmosphere. do. At this time, the control device 119 controls the second low-pressure stage degassing two-way valve 113, the first high-pressure stage degassing two-way valve 116, and the second high-pressure stage degassing two-way valve 117 in a closed state. do.

Next, in the case of an emergency in which the current stops flowing while the multi-stage air compressor 100 is operating and the operation is suddenly stopped, the control device 119 uses the first low-pressure stage degassing two-way valve 112, the first. The high-pressure stage degassing two-way valve 116 of 1 is closed, the second low-pressure stage degassing two-way valve 113 and the second high-pressure stage degassing two-way valve 117 are fully opened, and the low-pressure stage compressor main body 101 and the high-pressure stage are fully opened. It is controlled so that all the compressed air compressed by the compressor body 102 is released to the atmosphere. This makes it possible to prevent the low-pressure stage compressor main body 101 and the high-pressure stage compressor main body 102 from being damaged by the backflow of compressed air.

By the way, in this embodiment, unlike the above operating state, when the multi-stage air compressor is operated, when the intermediate pressure measured by the pressure detector 118 exceeds the set pressure, the multi-stage is conventionally performed. Where the operation of the air compressor is stopped, the operation is continued without stopping. The operation will be described below.

If the pressure detected by the pressure detector 118 exceeds the set upper limit pressure preset in the control device 119, the control device 119 can be used independently of the operation in order to reduce the pressure to the set upper limit pressure or less. An opening command is given to the second low-pressure stage degassing two-way valve 113 so as to open the low-pressure stage degassing two-way valve 113. Then, by opening the second low-pressure stage degassing two-way valve 113, a part of the compressed air is released to the atmosphere without being guided to the high-pressure stage compressor main body 102.

Further, the remaining compressed air is guided to the high-pressure stage compressor main body 102, further boosted to a predetermined discharge pressure and the temperature rises, and the compressed air whose temperature has risen is guided to the aftercooler 108 via the air pipe 109. After being cooled by the aftercooler 108, it is supplied to the user side from the discharge air pipe 120.

In the above embodiment, apart from the first low-pressure stage degassing two-way valve 112 for normal operation and the first high-pressure stage degassing two-way valve 116, the second low-pressure stage degassing two for emergencies. Although the square valve 113 and the second high-pressure stage degassing two-way valve 117 are provided, the first low-pressure stage degassing two-way valve 112, the first high-pressure stage degassing two-way valve 116, and the second low-pressure are provided. The stage degassing two-way valve 113 and the second high-pressure stage degassing two-way valve 117 are also used, one for each discharge side of the low-pressure stage compressor main body 101 and the high-pressure stage compressor main body 102. An air-discharging electromagnetic valve, which is a valve, may be provided.

Further, in the above embodiment, the multi-stage air compressor having a two-stage configuration in which two compressor main bodies are connected has been described, but the present invention is not limited to two stages, and may be three or more stages, and the compressor main body has at least two stages. Applicable for intermediate pressure between.

As described above, according to the present embodiment, even when the intermediate pressure of the multi-stage air compressor becomes a predetermined value or more, a part of the air compressed by the low-pressure stage compressor main body is released from the degassing solenoid valve to the outside air by a predetermined amount. Therefore, the compressor can continue to operate without stopping the operation.

In this embodiment, an example in which the amount of air released by the second low-pressure stage air exhaust two-way valve 113 can be adjusted will be described.

The system diagram of the multi-stage air compressor in this embodiment is the same as that in FIG.

FIG. 2 is a correspondence table between the set upper limit pressure and the valve opening degree, which is input in advance to the control device 119. That is, when the value exceeds the preset upper limit pressure with respect to the detection pressure detected by the pressure detector 118 of the multi-stage air compressor shown in FIG. 1, the control device 119 is shown in FIG. Determine the valve opening according to the correspondence table between the set upper limit pressure and the valve opening shown.

Specifically, when the multi-stage air compressor 100 is in operation, the control device 119 compares the pressure value detected by the input pressure detector 118 with the preset upper limit pressure. When the input pressure value exceeds the set upper limit pressure, the control device 119 determines the valve opening degree according to FIG. 2 in order to make the intermediate pressure equal to or less than the set upper limit pressure. The control device 119 issues an opening command to the second low-pressure stage degassing two-way valve 113 in order to open at the determined valve opening. If the input value does not exceed the set upper limit pressure, the control device 119 ends the process.

As described above, since the amount of air released from the second low-pressure stage air release two-way valve 113 changes according to the pressure detected by the pressure detector 118, unlike the first embodiment, the second low-pressure stage air release The amount of some compressed air released to the atmosphere from the air two-way valve 113 is minimized.

The remaining compressed air is guided to the high-pressure stage compressor main body 102, further boosted to a predetermined discharge pressure and the temperature rises, and the heated compressed air is guided to the aftercooler 108 via the air pipe 109. After being cooled by the aftercooler 108, it is supplied to the user side from the discharge air pipe 120.

As described above, according to the present embodiment, even when the intermediate pressure of the multi-stage air compressor exceeds a predetermined value, a part of the air compressed by the low-pressure stage compressor main body is discharged from the air release solenoid valve to the minimum outside air. Therefore, the compressor can continue to operate without stopping the operation.

FIG. 3 is a system diagram of the multi-stage air compressor in this embodiment. In FIG. 3, the same components as those in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted. In FIG. 3, the difference from FIG. 1 is that the third low-pressure stage degassing pipe 122 branches from the middle of the second low-pressure stage degassing pipe 111, and the third low-pressure stage degassing pipe 122 is connected to the third low-pressure stage degassing pipe 122. The low-pressure stage degassing two-way valve 123 of No. 3 was provided. The third low-pressure stage degassing two-way valve 123 is a degassing solenoid valve that can be used independently of operation, like the second low-pressure stage degassing two-way valve 113.

In this embodiment configured as described above, when the pressure detected by the pressure detector 118 exceeds the set upper limit pressure preset in the control device 119 when the multi-stage air compressor 100 is operated. In order to keep the intermediate pressure below the set upper limit pressure, the control device 119 uses the second low-pressure stage degassing two-way valve 113 and the third when the pressure detected by the pressure detector 118 is 0.3 MPa or more. An open command is given to the low pressure stage degassing two-way valve 123, and when the pressure detected by the pressure detector 118 is 0.2 MPa or more and less than 0.3 MPa, an open command is given to open either one.

The second low pressure stage degassing two-way valve 113 and the third low pressure stage degassing two-way valve 123, or one of them is opened, so that the second low pressure stage degassing two-way valve 113 and the third low pressure are The amount of a part of the compressed air released to the atmosphere from the stepped air release two-way valve 123 or one of them can be adjusted stepwise.

The remaining compressed air is guided to the high-pressure stage compressor main body 102, further boosted to a predetermined discharge pressure and the temperature rises, and the heated compressed air is guided to the aftercooler 108 via the air pipe 109. After being cooled by the aftercooler 108, it is supplied to the user side from the discharge air pipe 120.

As described above, according to the present embodiment, even when the intermediate pressure of the multi-stage air compressor exceeds a predetermined value, a part of the air compressed by the low-pressure stage compressor main body from the degassing solenoid valve is stepwise. Adjustable release to the outside air allows the compressor to continue operating without stopping.

FIG. 4 is a system diagram of the multi-stage air compressor in this embodiment. In FIG. 4, the same components as those in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted. In FIG. 4, the difference from FIG. 1 is that the fourth low-pressure stage air exhaust pipe 124 branches from the middle of the air pipe 106 connecting the intercooler 104 and the high-pressure stage compressor main body 102, and the fourth low-pressure stage compressor body 102 is branched. A fourth low-pressure stage air release two-way valve 125 is provided in the stage air discharge pipe 124. The fourth low-pressure stage degassing two-way valve 125 is a degassing solenoid valve that can be used independently of operation, like the second low-pressure stage degassing two-way valve 113.

In this embodiment configured as described above, when the pressure detected by the pressure detector 118 exceeds the set upper limit pressure preset in the control device 119 when the multi-stage air compressor 100 is operated. , The control device 119 issues an opening command to the fourth low-pressure stage degassing two-way valve 125 in order to open the fourth low-pressure stage degassing two-way valve 125 in order to bring the intermediate pressure to or less than the set upper limit pressure. The compressed air cooled by the intercooler 104 is released to the atmosphere from the fourth low-pressure stage degassing two-way valve 125 due to the opening of the fourth low-pressure stage degassing two-way valve 125. It is released to the air without being guided by the high-pressure compressor main body 102. Unlike the first embodiment, some of the compressed air released to the atmosphere at this time is cooled compressed air, so that it can be safely discharged to the outside.

The remaining compressed air is guided to the high-pressure stage compressor main body 102, further boosted to a predetermined discharge pressure and the temperature rises, and the heated compressed air is guided to the aftercooler 108 via the air pipe 109. After being cooled by the aftercooler 108, it is supplied to the user side from the discharge air pipe 120.

As described above, according to the present embodiment, even when the intermediate pressure of the multi-stage air compressor exceeds a predetermined value, a part of the cooled compressed air is released to the outside air, so that the compressor stops its operation. You can continue to drive without any problems.

Although the examples have been described above, the present invention is not limited to the above-mentioned examples, and includes various modifications. For example, in the above embodiment, the screw compressor has been described as an example, but a compressor such as a scroll type, a reciprocating type, or a rotary type can also be used. Further, each of the above-described embodiments has been described in detail in order to explain the present invention in an easy-to-understand manner, and the present invention is not necessarily limited to the one including all the components described above. Further, it is possible to replace a part of the configuration of a certain embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of a certain embodiment. Further, it is possible to add / delete / replace a part of the configuration of each embodiment with another configuration.

100: Multi-stage air compressor, 101: Low-pressure stage compressor body, 102: High-pressure stage compressor body, 103: Filter, 103A: Suction port, 104: Intercooler, 105: Air piping, 106: Air piping, 107: Reverse Stop valve, 108: Aftercooler, 109: Air piping, 110: First low-pressure stage degassing pipe, 111: Second low-pressure stage degassing pipe, 112: First low-pressure stage degassing two-way valve, 113: 2nd low-pressure stage degassing two-way valve, 114: 1st high-pressure stage degassing pipe, 115: 2nd high-pressure stage degassing pipe, 116: 1st high-pressure stage degassing two-way valve 117: 2nd High-pressure stage degassing two-way valve, 118: Pressure detector, 119: Control device, 120: Discharge air piping, 121: Pressure detector, 122: Third low-pressure stage degassing pipe, 123: Third low-pressure stage Two-way degassing valve, 124: 4th low-pressure stage degassing pipe, 125: 4th low-pressure stage degassing two-way valve

Claims (5)

It is a multi-stage air compressor that connects the air path of the low-pressure stage compressor body and the high-pressure stage compressor body in series.
The low-pressure stage compressor main body and the high-pressure stage compressor main body are connected by a first air pipe.
A pressure detector connected in the middle of the first air pipe,
The first air-discharging pipe that branches from the middle of the first air pipe and
The first solenoid valve provided in the first air exhaust pipe and
The pressure value detected by the pressure detector is input, and the control device for controlling the first air release solenoid valve is provided.
When the pressure detected by the pressure detector exceeds a predetermined value, the control device issues an opening command to the first release solenoid valve, and a part of the compressed air compressed by the low-pressure stage compressor main body. A multi-stage air compressor characterized by releasing the air to the outside air. In the multi-stage air compressor according to claim 1,
The first air exhaust pipe and the second air exhaust pipe branching from the middle of the first air pipe,
It has a second solenoid valve provided in the second exhaust pipe, and has a second solenoid valve.
The control device controls the second solenoid valve during operation, and controls the first solenoid valve when the pressure detected by the pressure detector exceeds a predetermined value regardless of the operation. A multi-stage air compressor characterized by In the multi-stage air compressor according to claim 1,
It has a correspondence table between the set upper limit pressure and the valve opening.
When the pressure detected by the pressure detector exceeds the set upper limit pressure, the control device controls the first degassing solenoid valve with the valve opening according to the corresponding table, and the low pressure stage compression. A multi-stage air compressor characterized by releasing a part of the compressed air compressed by the machine body to the outside air. In the multi-stage air compressor according to claim 2,
The third air exhaust pipe is branched from the middle of the first air exhaust pipe.
It has a third solenoid valve provided in the third exhaust pipe, and has a third solenoid valve.
The control device issues an opening command to the first solenoid valve, the third solenoid valve, or one of the solenoid valves according to the pressure detected by the pressure detector. A multi-stage air compressor characterized by discharging a part of compressed air compressed by the low-pressure stage compressor body to the outside air. It is a multi-stage air compressor that connects the air path of the low-pressure stage compressor body and the high-pressure stage compressor body in series.
An intercooler is provided between the discharge side of the low-pressure stage compressor main body and the suction side of the high-pressure stage compressor main body.
The intercooler is connected to the low-pressure stage compressor main body by a first air pipe, and is connected to the high-pressure stage compressor main body by a second air pipe.
A pressure detector connected in the middle of the second air pipe,
A fourth air-discharging pipe that branches from the middle of the second air pipe,
The fourth solenoid valve provided in the fourth air exhaust pipe and
The pressure value detected by the pressure detector is input, and the control device for controlling the fourth solenoid valve is provided.
When the pressure detected by the pressure detector becomes equal to or higher than a predetermined value, the control device issues an opening command to the fourth solenoid valve, is compressed by the low-pressure stage compressor main body, and is cooled by the intercooler. A multi-stage air compressor characterized by releasing a part of the compressed air to the outside air.

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