# Chuanfan Mechanical and Electrical Equipment (Kunshan) Co., Ltd

FAQ

FAQ

Air flow calculation

### Air flow(Q):(a.k.a. volume flow rate) the flow rate through the Cross-sectional area of pipe, the formula is: Q=60VA     Q (Air flow)=m3/min     V (Air velocity)=m/sec     A (Cross-sectional area)=m2

Common Conversion formula for pressure

### 1Pa=0.102mmAq1mbar=10.197mmAq1mmHg=13.6mmAq1psi=703mmAq1Torr=133.3pa1Torr=13.3 mmAq1Torr=1.333mbar

Common Conversion formula for air flow

### 1m3/min(CMM)=1000 l/min = 35.31 ft3/min(CFM)

Common Terms explanation

Pressure

### (1) Static pressure(Ps): The pressure of a fluid exerts on a surface at rest. It is resulted by gravity and impeller in blower and fan, which can be measured directly. Usually expressed in units with kgf/m2 or mmaq. (2) Velocity pressure(Pv): (a.k.a. Dynamic Pressure) The pressure of a fluid in motion. Usually expressed in units with kgf/m2 or mmaq.(3) total pressure: The sum of Static pressure plus Velocity pressure. Usually expressed in units with kgf/m2 or mmaq. The total pressure is a fixed value for blower and fan, it is not changed when reducing the diameter of pipe.

Air pressure and temperature

### Density of air changes with variances in temperature. If other conditions are fixed, the air pressure has to be adjusted by the following formula when variances in temperature:P= P'(273+t/293) (mmAq)Same reason, when variances in density of air:P=P'(1.2/γ) (mmAq)The P', t, andγare measured pressure, temperature, and density of air.

Air pressure and velocity

### Pressure is proportional to the velocity.Pv=γ×(V2 / 2g)Pv: Velocity pressure(mmAq)              γ: proportion of air(kg/m3)g: Acceleration of gravity(m/s2)=9.8       V: velocity(m/s)

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Contact Details
Manager Chen：13328058678