Can a Roots blower use an outlet valve to regulate flow?
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This post was last edited by chenwelse on 2011-6-15 17:18. The three-blade Roots blower in our factory (LSR250WD) does not have a bypass valve. Some people say that the flow rate can be adjusted using the outlet valve, while others claim that since it is a positive-displacement blower, the outlet valve cannot be used for flow control; a bypass valve is necessary for that purpose. May I ask: which one is correct? Or do they each have their own range of operation? Also, is it better to install the outlet check valve on a vertical pipe or on a horizontal pipe? Why?
Reply to 1# chenwelse: If the medium flowing through this Roots blower is a toxic gas, a recirculation circuit must be installed; if it’s air, then an exhaust system along with a silencer can be used. For check valves, it’s best to install them horizontally! At least mine is horizontal! ! Hehe
This post was last edited by chenwelse on 2011-6-15 23:42. Thank you for the answer. The medium is nitrogen. How could the designers fail to include a bypass/? Why was the valve installed on a horizontal pipe last time?/
Rotary vane blowers are positive displacement fans; the flow rate cannot be adjusted using an outlet valve, and it can only be controlled through a bypass or return circuit； Except where special requirements dictate installation in vertical pipes, check valves are generally installed in horizontal pipes.
Rotary vane blowers are primarily used to transport flammable, explosive, toxic, and valuable industrial gases. It belongs to the positive-displacement – rotary type. We transport gas, and there is a bypass.
This fan must not have its outlet adjusted; the outlet must be left fully open
A Roots blower is a positive-displacement pump, and its outlet must be fully open. To adjust the flow rate, it is possible to do so only by using the inlet valve or the recirculation valve; I think it’s better to install the outlet check valve in a vertical position. Due to the pulsations in the medium at the outlet of the Roots blower, the pressure is not stable; the outlet check valve is installed vertically, allowing its valve core to fall back naturally, thereby improving efficiency. The above are my personal opinions; please point out any shortcomings.
The correct procedure is: 1. Fully open the outlet valve； 2. Add bypasses and silencers to regulate flow through the bypasses ； 3. Check valves work better on horizontal pipes ；
It belongs to the category of positive displacement pumps; the outlet must be fully open. Flow rate can be adjusted using bypass circuits or return paths, or by installing an inverter on the motor. Whether it is installed horizontally or vertically depends on the type of check valve.
Whether it is installed horizontally or vertically depends on the type of check valve.
Thank you all; I now understand the issue with the bypass – it must be installed. The issue with the check valve needs to be discussed further.