Energy-saving Principle of Gas Supply at Constant Pressure,China Energy-saving Principle of Gas Supply at Constant Pressure,Energy-saving Principle of Gas Supply at Constant Pressure Manufacturer.

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Energy-saving Principle of Gas Supply at Constant Pressure

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Company Profile Tel ：+86 755 86312834 86028065 (direct line) Mobile: +86 136 326 868 69 Fax：+86 755 8602 8412 Tel ：+86 755 86312845 86028065 (direct line) Mobile: +86 130 778 019 09 Fax：+86 755 8602 8412 Tel ：+86-755-86312856 86318602 86318456 (direct line) Mobile: +86 133 169 613 20 /+86 135 100 656 90 Fax：+86-755-8602 8412

Product Description:

As the above-mentioned, flow is the fundamental control object of a gas supply system. The gas supply flow needs to meet the gas consumption flow anytime. In a gas supply system, the pressure in the gas storage pipeline can fully indicate the relationship between the gas supply capacity and the gas consumption demand.

If gas supply flow > gas consumption flow → the pressure inside the gas storage pipeline rises

If gas supply flow gas consumption flow→ the pressure inside the gas storage pipeline drops

If gas supply flow = gas consumption flow → the pressure inside the gas storage pipeline keeps unchanged

Therefore, if the gas pressure in the pipeline is constant, the gas supply capacity just meets the gas consumption demand. This is the purpose of a constant-pressure gas supply system.When an air compressor uses the VVVF (Variable Velocity and Variable Frequency) to make constant-pressure gas supply control, the block diagram of the system is as shown in Figure 18.

Figure 18 Block Diagram of Constant Pressure Gas Supply System

The VVVF system regards the pipeline pressure as a control object. A pressure transmitter at the outlet of the gas storage pipeline converts the pressure of the gas storage tank into electric signals, sends the signals to the PID regulator, compares them with the pressure settings, makes calculation according to the set PID control mode based on the size of the difference, generates a control signal to control the output voltage and inversion frequency of the inverter, adjust the rotation speed of the motor, so that the actual pressure is maintained at the given pressure all the time. In addition, when this solution is used, the inverter can implement soft start of the motor of the air compressor from static to stable rotation speed, avoiding the mechanical impact of large current and start to the air compressor upon startup. In normal conditions, the air compressor operates in the VVVF control mode. Once the inverter fails, the production process does not allow the suspension of the air compressor, so the system is configured with the function of switchover between the power frequency and the variable frequency. In this way, when the inverter fails, the power frequency can directly supply power through the contactor so that the air compressor can operate normally as usual.

The whole control process is follows:

Gas consumption demand ↑-----pipeline pressure ↓ Difference between pressure setting and feedback value ↑----- PID output ↑----- output frequency of inverter ↑----- rotation speed of air compressor motor ↑----- gas supply flow ↑----- stabilization of pipeline pressure

Figure 19 PID Curve of Pressure and Frequency

Please note that the PID of the inverter does not conduct adjustment within the pressure tolerance range, that is, the output frequency keeps unchanged.

Figure 20 Variable Frequency Electric Control of Air Compressor

As shown in Figure 20, "mains supply” and “energy saving” contactors are configured for the circuit of the air compressor motor. Thus, there are two optional operational modes of “mains operations” and “energy-saving operation”: In the mains operation mode, the inverter does not work, and the entire system starts/stops manually and operates at the power frequency according to the original mode; while in the energy-saving operation mode, the air compressor is directly driven by the inverter, and the system automatically adjusts the rotation speed of the air compressor motor according to gas consumption so that the gas storage tank maintains a constant pressure output.

Summary

The introduction of the VVVF technology into the air compressor field is an important subject under the research of air compressor manufacturers in recent years. Major vendors of famous air compressor brands have launched their own variable frequency compressors and have achieved outstanding performance in high-end markets rapidly. However, at present power frequency compressors have found wide application, so there is a tremendous compressor reconstruction market. We sincerely hope that our solution of reconstruction compressors by use of inverters can help system integrators, final users and electrical automation fans, or provides a new consideration.