# News

(1), pressure: the pressure referred to in the compressor industry refers to pressure (P)

Ⅰ, standard atmospheric pressure (ATM)

Ⅱ, working pressure, suction, exhaust pressure, refers to the air compressor suction, exhaust pressure

① The pressure measured with atmospheric pressure as the zero point is called surface pressure P(G).

② The pressure with absolute vacuum as the zero point is called the absolute pressure P(A).

The exhaust pressure usually given on the compressor nameplate is the gauge pressure.

Ⅲ, differential pressure, pressure difference

Ⅳ, loss of pressure: pressure loss

Ⅴ, air compressor, the commonly used pressure unit conversion:

1MPa (MPa) =106Pa (PASCAL)

1bar (bar) =0.1MPa

1atm (standard atmospheric pressure) =1.013bar=0.1013MPa

Usually in the air compressor industry, “kg” refers to “bar”.

(2), nominal flow: nominal flow in China is also known as the displacement or nameplate flow.

Generally speaking, under the required exhaust pressure, the gas volume discharged by the air compressor per unit time is converted to the intake state, which is the volume value of the suction pressure and suction temperature and humidity at the first stage of the intake pipe. Unit time refers to one minute.

That is, the suction volume Q= CM *λ*D3*N=L/D*D3N

L: Length of rotor

D: Diameter of the rotor

N: The shaft speed of the rotor

CM: Coefficient of profile line

Lambda: length to diameter ratio

According to the national standard, the actual exhaust volume of air compressor is ± 5% of the nominal flow.

Reference state: a standard atmospheric pressure, temperature 20℃, humidity is 0℃, this reference state in the United States, Britain, Australia and other English-speaking countries T =15℃. Europe and Japan T =0℃.

Standard condition: one standard atmosphere, temperature 0℃, humidity 0

If converted to base state, the unit is :m3/min (cubic per minute)

If converted to standard state, the unit is :Nm3/min (standard square per minute)

After 1 m/min = 1000 l/min

1 nm after/min after = 1.07 m/min

(3) Oil content of gas:

Ⅰ, per unit volume of compressed air in the oil (including oil, suspended particles and oil steam), the quality of the conversion to off the pressure of 0.1 MPa, temperature is 20 ℃ and relative humidity of 65% the value of the standard atmospheric conditions. Unit :mg/m3 (refers to absolute pair value)

Ⅱ, PPM said a trace substances content in the mixture of symbols, refers to the number in every one million hundreds million (weight than PPMw and volume than PPMv). (referring to the ratio)

Usually we refer to PPM as the weight ratio. (One millionth of a kilogram is a milligram)

1PPMW =1.2mg/m3(Pa =0.1MPa, t=20℃, φ=65%)

(4) Specific power: refers to the power consumed by a certain volume flow of the compressor. It is a kind of index to evaluate the compressor performance under the same gas compression and the same exhaust pressure.

Specific power = shaft power (total input power)/ exhaust (kW/m3·min-1)

Shaft power: The power required to drive the shaft of the compressor.

P axis =√3×U×I× COS φ(9.5)×η(98%) motor ×η drive

(5), electrical and other terms

Ⅰ, power: current per unit time to do the work (P), the unit is W (watt

We usually use kW (kilowatt), but also horsepower (HP)

1 KW HP1HP = 1.34102 = 0.7357 KW

Ⅱ, current: electronic under the action of electric field force, there are rules of move in one direction

When it moves, it forms A current in A amperes.

Ⅲ, voltage: just because have head and water flow, there is also a potential difference,

It is called voltage (U), and the unit is V (volts).

Ⅳ, phase, refers to the wire, three phase four wire: refers to the three phase thread (or wire)

The center line (or zero line), single phase refers to a phase line (or fire line)

Root center line (or zero line)

Ⅴ, frequency: alternating current (ac) to complete the electromotive force of the positive and negative transformation cycles a second number, use (f), according to the unit – Hertz (Hz) of 50 Hz alternating current frequency in our country, abroad is 60 Hz.

Ⅵ, frequency: change the frequency, in air compressor application, by changing the frequency of the power to change the speed of the motor, so as to achieve the purpose of flow adjustment. The flow rate can be adjusted to 0.1bar by frequency conversion, which greatly reduces idle work and achieves the purpose of energy saving.

Ⅶ, controller: there are two main types of controller in industry: instrument type and PL

System, we use PLC controller, is a kind of by

A programmable controller composed of single chip microcomputer and other components.

Ⅷ, straight league: direct connection, in the air compressor industry refers to bind with coupling

Ⅹ, air/water: refers to the cooling way

Ⅺ, noise: unit: dB (A) (+ 3) (dB) unit of sound pressure level

Ⅻ, protection grade: it is said dustproof electric equipment, prevent a foreign body, waterproof, etc

The value of the degree of airtightness is expressed by IPXX

Ⅷ, startup mode: direct start, usually start with star triangle transformation way.

(6) Dew point temperature unit ℃

Wet air under such pressure cooling, make originally contains unsaturated water vapor in the air becomes saturated steam temperature, in other words, when reduced to a certain temperature, the temperature of the air in the air it contains unsaturated water vapor to reach saturation state (namely the steam begins to liquefaction, liquid condenses out), the temperature is the dew point temperature of the gas.

Pressure dew point: refers to the gas with a certain pressure cooled to a certain temperature, the unsaturated water vapor contained in it becomes saturated water vapor precipitation, the temperature is the pressure dew point of the gas

Atmospheric dew point: at standard atmospheric pressure, a gas cools so that its contents are not full

Water vapor becomes saturated water vapor exhales to a temperature

In the air compressor industry, dew point is the degree of dryness of the gas

Post time: Nov-03-2021