Vacuum system composed of Roots blowers and ejectors
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In a vacuum system formed by connecting the two together, is the fan at stage 1 or is the ejector placed first?
It’s rare to see such a combination; it’s better to have the fan at the front
What is the principle regarding which one comes first? In cases where the fan is located at the front and the ejector at the back, water is used as the power source (the pumping medium).
What I’m considering is the issue of water getting into the fan.
A two-stage Roots pump is at the front, with an ejector connected in series behind it. Rotary vane pumps have good pumping performance at low pressures and a high compression ratio.
We use a combination of rotary vacuum pumps and reciprocating vacuum pumps in series; the rotary vacuum pump is used first to perform vacuum pumping, while the reciprocating pump is used for vacuum pumping last.
A Roots vacuum pump cannot be used alone; it must be used in conjunction with a pre-stage pump. During operation, start the pump ahead first to reduce the pressure to the starting pressure of the Roots pump, and then start the Roots vacuum pump. From the gas flow perspective, the gas flows into the advanced Roots pump first and then into the preceding stage pump. In terms of the operation sequence, the pump at the previous stage is started first, followed by the Roots pump. The primary pump can be a water ring vacuum pump, steam ejector, water jet pump, rotary vane vacuum pump, screw vacuum pump, etc.
The jet pump draws air first; the Roots vacuum pump is started only after reaching -0.092 MPa. The Roots vacuum pump is located right next to the reaction vessel, while the outlet of the ejector pump leads directly to the atmosphere (or other pumps such as reciprocating pumps or screw vacuum pumps can be used). ）