vac pump

[dai kin]

Hi guys,i am after some advice about a vac pump that i lent to a fellow engineer and when i got it back the oil was very milky!so i changed the oil and it has been on the van for a couple of weeks.Then today i used it to vac out a new install which got down to two torr and held it ok,but the oil is milky again and there was a few drops of water inside the handle(outlet)of the pump!So do you think this was still in the pump or do you think i had (poss still have)moisture in my new install?

[Brian_UK]

Probably still in the pump, the fact that you held a test vacuum discounts that much moisture.

Change the oil, run the pump with the ballast valve open to vac out a cylinder or similar, repeat until the oil clears.

[Karl Hofmann]

My two Robinair vac pumps must be the most pampered vac pumps in the country, I regularly inspect the oil that comes from them and if needed I will change the oil, run them for a while and then change again. It is surprising the difference this makes to the performance..

[Electrocoolman]

Speaking with the JAVAC rep at the show regarding oil, and the grade (viscosity) can make a huge difference to the performance.
Have been using 46 grade but he recommends 100. You dont need special vac pump oil....hydraulic oil is more than suitable....eg shell Tellus.

[Cofreth]

I see some ppl use auto engine oil too. :-)

[Andy]

Hi Guys:)

we are in the process of evacuating a shell and tube brine chiller that has burst it's titanium tubes. We have two pumps running at the moment. A fridge vac pump 2 stage 10 cfm and an industrial single stage 30 cfm pump. The fridge pump needs the oil changed every hour, but the industrial pump will last 4 hours;) It occurs to me that the sump design is important in keeping the oil clean. In general the industrial pump is much better at keeping a good vacumn over a period of time. Fridge vac pump designers should take note. I will be considering buying a Bush in the near future.;)

Kind Regards Andy:)

[Electrocoolman]

Andy,
Busch are good pumps....used alot in Vacuum packing machines. They have a filter (possibly x2) built in.
I know they are high volume, but not sure what ultimate vacuum level is that they can achieve.

Oil change can sometimes be like emptying Brylcream when they haven't been serviced regularly!

[Pooh]

I always changed the oil in my vac pump before I used it and if the oil looked milky afterwards as well which meant that the oil in the pump was always good and my Edwards pump is 10 years old now and still going strong.

Ian

[fridg]

We use inland oil , and during winter will use inland 19 ,
during summer inland 21. On commercial pumps and will pull a vacuum of 9 micron on the pump.

Seals and lubricates well.

http://www.inlandvacuum.com/mechanicalfluids.html

[Andy]

Andy,
Busch are good pumps....used alot in Vacuum packing machines. They have a filter (possibly x2) built in.
I know they are high volume, but not sure what ultimate vacuum level is that they can achieve.

Oil change can sometimes be like emptying Brylcream when they haven't been serviced regularly!

We tested the pump with the valve shut it can obtain 1500 microns:) Good for a single stage pump and fine for an Ammonia system;)
Our two stage JB pumps will obtain 150 microns, eventually:o

Kind Regards Andy:)

[aawood1]

Hi, We use Busch vac. pumps all the time on Ammonia systems, The two vac pumps we use one 3ph. and the other one single phase and they have two filters built in. We change the oil after each pump down/Vac out. Did fit Danfoss 1/2" non-return valves on the outlets after one stoped and sucked the purge water back into the pump. ( we fit a non-return at the connection point as std.) Have seen one of the pumps when I came onto shift looking like a block of ICE as it was pumping liquid !! and the fitter did not understand why I called him a unsafe C***. The vac. pump still worked OK later.
All the best Arthur.