How to stop a vacuum pump
Vol.20 #2, July 1993
Sure you push the stop button ... and, in case of liquid ring vacuum pumps, steam and water comes pouring out of the extruder vent stack: The remaining vacuum in the pipes and vent dome is typically strong enough to pull the sealing liquid (mostly water) upstream into the extruder. As a consequence, the melt freezes immediately and steam leakage can cause a potential for injury.
A bleeding valve installed right at the vent dome can be used to break the vacuum, before the pump is stopped, and the problem of back flushing is prevented.
See also:
- Vent bleed
- Vent plugging
- Vents 1
- Vents 2
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Extrusion Hints