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Introduction to selection method of Roots blower?

Source: Roots blower manufacturer Published on: January 13, 2024 Hits:

Introduction to selection method of Roots blower? Flow conversion of Roots blower:

(1) Flow conversion under different conditions.

① Flow conversion under reference state and inlet state. The flow in the process flow is usually based on the reference state (temperature 0C, pressure

Q: (Nm2/min) under the force of 101. 325kPa). QN can be converted into the flow under the actual intake state by the following formula:

　　Qs= QN●273 + ts/273●101.325/101.325+ps (m ³/ min)

Where ts is the inlet air temperature, ℃; Ps is the inlet pressure (gauge pressure), kPa.

The sample flow of Roots blower is usually the flow under the standard suction state (i.e. the air state with 20 ℃, 101.325kPa and 50% relative humidity). Regardless of the influence of humidity, Qn can be converted into the flow under the standard suction state according to the following formula:

　　Qs = 1.07326Qn (m3 /min)

② The flow conversion formula under intake and exhaust conditions is:

　　Qs=Qd●273+ ts/273+td●101 .325 + Pd/101.325+ Ps(m ³ / min)

Where td is the exhaust temperature, ℃; Pd is the exhaust gauge pressure, kPa; Qd is the exhaust flow, m ³/ min。

(2) Flow conversion under different working conditions. The following differences may exist between the actual working condition and the sample working condition: the medium is not air

The gas temperature ≠ 20 ℃, the pressure ratio and rotating speed are inconsistent with the sample values. In case of large difference, flow conversion shall be conducted.

① The theoretical flow at actual speed is:

　　Qth = Qtha●n/na (m ³/ min)

Where, n is the actual speed, r/min; Na is the rotational speed under sample working condition, r/min; Qtha is the theoretical flow rate at the sample speed, m ³/ min。

② The leakage flow under the sample condition is:

　　Qba= Qtha- Q5a(m ³ / min)

Where Q5a is the "actual flow" under the sample working condition, m ³ / min。

③ Leakage flow under actual working condition is:

Qb=273+ts/293 under Qba radical 29/M. ε- 1/ ε a- 1(m3 /min)

Where ts is the actual intake air temperature, ℃; M is the molecular weight of gas, air M=29; ε Is the actual pressure ratio; ε A is

Pressure ratio under sample condition.

④ The actual flow is:

　　Qs=Qth-Qb( m ³ / min);

Example of Roots blower selection:

(1) When the flow is expressed by the value Qn (Nm3/min) under the reference state, the parameters on the product sample cannot be directly quoted.

For example, the air inlet is in the standard suction state, the pressure rise is 49kPa, and the required flow is 7.90Nm3/min. Guarantee the flow