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Oil from the Exhaust Port of Pump


If you are involved in vacuum filtration, have large air leaks, or just exhibiting these problems, this is not unusual.  In filtration or drying it is possible that a large portion of what you are drying off your samples is ending up in the pump. Then you have two problems.  Contamination of the pump and generally rising oil levels inside the pump from the condensed material, solvent, or water.

Contamination In Pump

1. You are contaminating your pump with your wash material or what is drying of the filtered product. Some simple solutions are as follows.

a. Change the oil frequently to eliminate contaminate.

      1. Use a separatory funnel or transparent funnel with a spigot on the bottom to recycle the good oil.  HyVac oils have very good demulsibility and depending on vacuum pressure desired you may find you can recycle your contaminated oil.  This is basically resolved through trying it out.  We are attempting to decant off the bad oil or contaminates and retain the good.  Sometimes if it is feasible adding heat to the mix can increase the yields.

b. Install a cold trap to remove condensable vapors from air stream.

Oil coming from exhaust port

2. You are operating at high pressures (not full vacuum) and are having high gas flows and oil mist (smoke), pump gurgling and might be making a real fine oil mess all around the pump.  Depending on the pump buy generally oil sealed pumps have very tight tolerances to make them achieve high vacuum numbers.  If you really don't need those vacuum numbers and are quite happy with 27" Hg and the system is leaking all over the place then you pump will misbehave some.  This is normal, nature of the beast.  There are some thing you might try to help alleviate this problem...

a. Raise exhaust port using standard pipe fittings or quick disconnect vacuum fittings.

b. Install a coalescing exhaust filter to stop oil from exiting pump.  HyVac exhaust filters are designed to stop oil mist which requires to a minor degree a special filter.  Not any old off the shelf filter will do it.  Our oil filters are rated at like 99.9% or something like that.

c. Clean up your pump and confirm that the oil mess was from exhaust port and not a leak from the pumps shaft seal, O-rings or the housing gaskets.

3. Sometimes with a wet vacuum system enough condensable vapors come across go into the pump and then turn back into a liquid in the pump oil which then increases the overall liquid level in the oil sump of the pump.  There is an airspace in these pump, but if we fill this up with other liquid, along with the original oil, then the next time you go to start the pump, it sucks in a large gulp of air but the air has no where to go and ends up pushing the oil and extra liquid right out the exhaust port of the pump as the intake of air displaces this volume.


11/27/2005 ęCopyright HyVac Products, Inc. All Right Reserved
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