A method for monitoring and preventing air compressor surge

Abstract

The present invention relates to the measurement of mechanical vibration, specifically a method for monitoring and preventing air compressor surge, which includes installing a vibration sensor on the air compressor body, installing an ammeter on the motor bus of the air compressor, installing an air volume sensor and an electric control valve on the air compressor outlet, and also includes a host computer suitable for running on a computing device and connected to the vibration sensor, the ammeter, the air volume sensor and the electric control valve, and monitoring and preventing air compressor surge according to 11 steps. Compared with the prior art, the present invention performs a comprehensive evaluation through three reference quantities of vibration, current and air volume, which can prevent the occurrence of false alarm surge problems, effectively avoid the high-speed centrifugal air compressor from operating under surge conditions, and protect the air compressor itself and the personal safety of the operator.

Description

Technical Field

[0001] The invention relates to the measurement of mechanical vibration, in particular to a method for monitoring and preventing air compressor surge. Background Art

[0002] When the air compressor is first started, since the air outlet is in a pressure-free state, low-frequency self-vibration will occur under the drive of the motor; after the air compressor is started, the pressure at the air outlet increases accordingly, and the low-frequency self-vibration is eliminated. In order to achieve a higher output air pressure, the air pressure will be increased by gradually closing the valve to reduce the flow rate. However, during the increase process, when the pressure at the air outlet exceeds the surge limit of the air compressor itself, the air compressor will be in a low-frequency and large-scale vibration state, which will endanger the safety of the air compressor itself and the personal safety of the operator. Summary of the invention

[0003] In order to prevent a high-speed centrifugal air compressor from operating under surge conditions and protect the air compressor's own safety and the personal safety of operators, the present invention provides a method for monitoring and preventing air compressor surge. The technical solution adopted is:

[0004] Install vibration sensors on the air compressor support feet, install ammeters on the motor busbars of the air compressor, install air volume sensors and electronically controlled valves at the air compressor outlet, and also include a host computer suitable for running on a computing device and connected to the vibration sensor, ammeter, air volume sensor and electronically controlled valve. Follow the following steps to monitor and prevent air compressor surge:

[0005] S1 presets the vibration limit to the upper computer;

[0006] S2 starts the air compressor, and the air compressor starts working;

[0007] The S3 ammeter monitors the current of the air compressor and transmits the monitoring data to the host computer in real time. The host computer processes the received current data.

[0008] The S4 vibration sensor monitors the vibration of the air compressor and transmits the monitoring data to the host computer in real time. The host computer processes the received vibration data.

[0009] The S5 air volume sensor monitors the air volume of the air compressor and transmits the monitoring data to the host computer in real time. The host computer processes the received air volume data.

[0010] S6 determines whether the current drops, if not, go to S8, if yes, go to S9;

[0011] S7 determines whether the gas output volume drops significantly, if not, go to S8, if yes, go to S10;

[0012] The S8 host computer issues a command to gradually reduce the opening of the electronically controlled valve and continue pressurizing;

[0013] S9 determines whether the current drops suddenly, if not, go to S8, if yes, go to S10;

[0014] S10 determines whether the vibration value exceeds the limit value preset in S1; if not, it goes to S2 to continue monitoring, if yes, it goes to S11;

[0015] The S11 host computer issues a command to gradually increase the opening of the electronically controlled valve until the vibration value is less than the preset limit of S1, and then switches to S2 to continue monitoring.

[0016] Furthermore, the vibration limit value preset in S1 is determined by the following method: before the air compressor leaves the factory, a vibration sensor is installed on the air compressor support foot, a manual valve is installed at the air outlet of the air compressor, and the air compressor is turned on. After the air compressor is operating normally, the opening of the manual valve is gradually reduced manually to artificially make the air compressor enter the surge zone. The vibration frequency corresponding to the moment of entering the surge zone is the vibration limit value.

[0017] Furthermore, a vibration sensor is installed on each leg of the air compressor. When the upper computer determines whether the vibration value exceeds the limit value preset by S1, the vibration value is the average value of the monitoring data transmitted by these vibration sensors.

[0018] Compared with the prior art, the present invention performs a comprehensive evaluation through three reference quantities, namely vibration, current and air volume, which can prevent the problem of false surge alarms, effectively avoid the operation of high-speed centrifugal air compressors under surge conditions, and protect the safety of the air compressor itself and the personal safety of the operators. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0020] The present invention will be further described below in conjunction with the accompanying drawings.

[0021] The inventor found that when the air compressor is in the no-load process, the motor bus current of the air compressor will increase with the speed. During the loading process after the speed stabilizes, the bus current will rise according to the parabolic curve and reach the maximum bus current at a pressure value. After this pressure value, the bus current will decrease. Before the surge point, the bus current will drop sharply and the slope will increase sharply. At the same time, during the continuous increase of the pressure of the air compressor, the air volume at the air outlet will continue to decrease, and the reduction amplitude has a fixed slope, but when the slope fluctuates sharply, the air compressor will enter the surge zone. However, a sharp drop in bus current and / or a sharp fluctuation in slope do not necessarily lead to surge. If the bus current is monitored to see whether it drops sharply or / and whether the slope fluctuates sharply, there will be a problem of false alarm. Therefore, the present invention also introduces a reference quantity of real-time vibration monitoring. Only when the three reference quantities are available at the same time, real-time control is performed, so as to accurately monitor and prevent air compressor surge, so that the air compressor is always in the best working condition.

[0022] The specific method of monitoring and preventing air compressor surge is to install a vibration sensor on each leg of the air compressor, install an ammeter on the motor bus of the air compressor, install an air volume sensor and an electric control valve at the air compressor outlet, and connect the host computer with the vibration sensor, ammeter, air volume sensor and electric control valve. The host computer is suitable for running on a computing device. Follow the steps below to monitor and prevent air compressor surge:

[0023] S1 presets the vibration limit value to the upper computer; the method of preset vibration limit value is: before the air compressor leaves the factory, install a vibration sensor on the air compressor support foot, install a manual valve at the air outlet of the air compressor, turn on the air compressor, and after the air compressor is running normally, manually gradually reduce the opening of the manual valve to artificially make the air compressor enter the surge zone. The vibration frequency corresponding to the moment of entering the surge zone is the vibration limit value.

[0024] S2 starts the air compressor, and the air compressor starts working;

[0025] The S3 ammeter monitors the current of the air compressor and transmits the monitoring data to the host computer in real time. The host computer processes the received current data.

[0026] The S4 vibration sensor monitors the vibration of the air compressor and transmits the monitoring data to the host computer in real time. The host computer processes the received vibration data.

[0027] The S5 air volume sensor monitors the air volume of the air compressor and transmits the monitoring data to the host computer in real time. The host computer processes the received air volume data.

[0028] S6 determines whether the current drops, if not, go to S8, if yes, go to S9;

[0029] S7 determines whether the gas output volume drops significantly, if not, go to S8, if yes, go to S10;

[0030] The S8 host computer issues a command to gradually reduce the opening of the electronically controlled valve and continue pressurizing;

[0031] S9 determines whether the current drops suddenly, if not, go to S8, if yes, go to S10;

[0032] S10 determines whether the vibration value exceeds the limit value preset in S1; if not, it goes to S2 to continue monitoring, if yes, it goes to S11; the vibration value is the average of the monitoring data transmitted by the vibration sensor on each leg;

[0033] The S11 host computer issues a command to gradually increase the opening of the electronically controlled valve until the vibration value is less than the preset limit of S1, and then switches to S2 to continue monitoring.

[0034] Parts not described in detail in this embodiment are prior art or common knowledge in the art.

Claims

1. A method for monitoring and preventing air compressor surge, characterized in that: A vibration sensor is installed on the air compressor body, an ammeter is installed on the motor bus of the air compressor, an air volume sensor and an electric control valve are installed at the air compressor outlet, and a host computer suitable for running on a computing device and connected to the vibration sensor, ammeter, air volume sensor and electric control valve is included to monitor and prevent air compressor surge in accordance with the following steps: S1 presets the vibration limit to the upper computer; S2 starts the air compressor, and the air compressor starts working; The S3 ammeter monitors the current of the air compressor and transmits the monitoring data to the host computer in real time. The host computer processes the received current data. The S4 vibration sensor monitors the vibration of the air compressor and transmits the monitoring data to the host computer in real time. The host computer processes the received vibration data. The S5 air volume sensor monitors the air volume of the air compressor and transmits the monitoring data to the host computer in real time. The host computer processes the received air volume data. S6 determines whether the current drops, if not, go to S8, if yes, go to S9; S7 determines whether the gas output volume drops significantly, if not, go to S8, if yes, go to S10; The S8 host computer issues a command to gradually reduce the opening of the electronically controlled valve and continue pressurizing; S9 determines whether the current drops suddenly, if not, go to S8, if yes, go to S10; S10 determines whether the vibration value exceeds the limit value preset in S1; if not, it goes to S2 to continue monitoring, if yes, it goes to S11; S11 The host computer issues a command to gradually increase the opening of the electronically controlled valve until the vibration value is less than the preset limit of S1, and then switches to S2 to continue monitoring; The preset vibration limit value in S1 is determined by the following method: before the air compressor leaves the factory, a vibration sensor is installed on the air compressor body, a manual valve is installed at the air outlet of the air compressor, the air compressor is turned on, and after the air compressor is running normally, the opening of the manual valve is gradually reduced manually to artificially make the air compressor enter the surge zone. The corresponding vibration frequency when entering the surge zone is the vibration limit value; A vibration sensor is installed on each body of the air compressor. When the host computer determines whether the vibration value exceeds the preset limit of S1, the vibration value is the average of the monitoring data transmitted by these vibration sensors.

Images