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# Knowledge of air compressor

1. Air compressor input specific power

Unit input specific power refers to the ratio of the unit's input power to the exhaust volume under the specified exhaust pressure of the air compressor unit: unit input specific.

power = unit input power / exhaust volume.

The unit is: kW / (m3 / min). According to "GB19153 Volumetric Air Compressor Energy Efficiency Limit Values and Energy Efficiency Levels", the specific power of air compressor units at different pressures has different energy efficiency level limits.

2. Air-to-Electric ratio

air-to-electric ratio Each cubic meter of compressed air produced by amount of electricity consumed when the air compressor unit at work, The unit is KW*H/m3.

D = E / G

D = Air-to-electric ratio of air compressor unit (KW * H / m3)

E = Total power consumption of air compressor unit (KW * H)

G = total air supply of the air compressor unit during the measurement period (m3)

The value of gas-electricity ratio under a certain pressure can be obtained by dividing the specific power value under that pressure by 60 Air-to-electric = specific power ÷ 60

3. Calculation of diameter of compressed air pipeline

In principle, the pressure drop of the piping should not exceed 5% of the operating pressure of the air compressor, so when rounding the calculated value according to the standard pipe size table, the larger one should not be smaller.

d-Compressed air pipe diameter (mm);

Q Air compressor nameplate displacement (m3 / min)

P-Air compressor exhaust pressure (gauge pressure) (MPa);

V-Economic velocity of compressed air in the pipeline (m / s).

a)Q<6m3/min时， Vc=0.2Q

b)Q=6-30 m3/min时， Vc=0.15Q

c)Q>30 m3/min时， Vc=0.1Q

4.Air tank size estimation

Vc—the minimum volume of the buffer tank, in cubic meters (m3);

Q outside-gas supply at the inlet of the gas storage tank (m3 / min);

T-The time (min) for the pipe network pressure to drop from P1 to P2;

P1-The pressure of the gas stored in the gas storage tank (MPa);

P2-The minimum pressure (MPa) that the gas in the gas storage tank is allowed to drop.

The estimated results can be rounded according to the volume of the air tank specified in JB / T8867 "Fixed Reciprocating Piston Air Compressor Air Tank": 0.3, 0.5, 1, 2, 3, 4, 5, 6, 8, 10, 12 whole. The following empirical data for the selection of gas storage tanks are provided for reference (Q: gas production capacity of air compressor unit (station), minimum volume of gas storage tanks)

5. When the air displacement of the air compressor is not enough let the pressure cannot be increased. Than the air displacement of the air compressor needs to be increased to determine.

ΔQ-Air compressor displacement m3 / min to be increased;

Q original-the original air compressor displacement m3 / min;

P Real-the target working pressure bar that the system needs to achieve;

P original-the working pressure bar that the original air compressor can reach.

Reference:

http://www.compressor.cn/

https://wenku.baidu.com/view/e1479f20a5e9856a56126085.html

https://wenku.baidu.com/view/876d9a2e453610661ed9f455.html

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Update time：2020-04-27 09:56:32

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