megalomania
June 7th, 2003, 09:32 PM
10fingers
Frequent Poster
Posts: 411
From: USA
Registered: SEP 2000
posted 04-27-2001 09:14 AM
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I have a vacuum pump that uses oil. It is a special type of oil and costs $15.00 per liter. I am trying to find a less expensive substitute.
Does anyone know if you could use automatic transmisson fluid, synthetic motor oil etc. It would have to be something that does not harm rubber seals, is a good lubricant and has a low vapor pressure.
wantsomfet
Frequent Poster
Posts: 236
From: EU
Registered: JAN 2001
posted 04-27-2001 11:26 AM
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I think it has to be this special oil. It has to have specific properties that normal oil etc. doesn't have.
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for best catfood visit:
catfood.tsx.org
c0deblue
Frequent Poster
Posts: 229
From:
Registered: JAN 2001
posted 04-27-2001 08:18 PM
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Wantsomfet is right - it is a special oil. You might do better from a refrigeration supplier (depending on your application), but don't fool around with something that could easily mean an even more expensive pump rebuild. A reasonable grade of oil for the refrigeration trade can be had for $6.50 a quart: http://www.airsource.com/cgi-bin/SoftCart.exe/scstore/p-13203.html?E+scstore
The greatest loss of oil occurs when pumping down from atmospheric pressure, when large quantities of oil are blown out through the exhaust port. Filter/mufflers do a fair job of recovering a lot of this, or you can use a column packed with stainless steel scouring pads. Mounted vertically, this will catch almost all the escaping oil and drain it back into the pump.
For ordinary work or as a roughing pump, a charge of inexpensive pump oil will do fine and last quite a while. However, if you're pumping from a contaminated atmosphere or using the unit as a backing pump in a diffusion system you should use a higher grade of oil and change it regularly.
BTW, if you think $15 a litre is bad, wait 'til you contaminate your $200+ diffusion fluid with an inferior product - that'll *really* make you cry. Been there, done that
Anthony
Moderator
Posts: 2306
From: England
Registered: SEP 2000
posted 04-27-2001 08:24 PM
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My pump was empty of oil when I went to use it and it ran fine (I was surprised to find it had no oil). Lacking hydraulic or pump oil I put a load of Dot5 fork oil in.
Seems to work and I've had it pumping for about 45mins continuous so far without any signs of trouble.
10fingers
Frequent Poster
Posts: 411
From: USA
Registered: SEP 2000
posted 04-27-2001 11:48 PM
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No, I don't want to use an inferior oil. I had heard awhile back that there is an oil that is used for something else but is cheaper and of the exact same composition as vacuum pump oil.
Frequent Poster
Posts: 411
From: USA
Registered: SEP 2000
posted 04-27-2001 09:14 AM
--------------------------------------------------------------------------------
I have a vacuum pump that uses oil. It is a special type of oil and costs $15.00 per liter. I am trying to find a less expensive substitute.
Does anyone know if you could use automatic transmisson fluid, synthetic motor oil etc. It would have to be something that does not harm rubber seals, is a good lubricant and has a low vapor pressure.
wantsomfet
Frequent Poster
Posts: 236
From: EU
Registered: JAN 2001
posted 04-27-2001 11:26 AM
--------------------------------------------------------------------------------
I think it has to be this special oil. It has to have specific properties that normal oil etc. doesn't have.
------------------
for best catfood visit:
catfood.tsx.org
c0deblue
Frequent Poster
Posts: 229
From:
Registered: JAN 2001
posted 04-27-2001 08:18 PM
--------------------------------------------------------------------------------
Wantsomfet is right - it is a special oil. You might do better from a refrigeration supplier (depending on your application), but don't fool around with something that could easily mean an even more expensive pump rebuild. A reasonable grade of oil for the refrigeration trade can be had for $6.50 a quart: http://www.airsource.com/cgi-bin/SoftCart.exe/scstore/p-13203.html?E+scstore
The greatest loss of oil occurs when pumping down from atmospheric pressure, when large quantities of oil are blown out through the exhaust port. Filter/mufflers do a fair job of recovering a lot of this, or you can use a column packed with stainless steel scouring pads. Mounted vertically, this will catch almost all the escaping oil and drain it back into the pump.
For ordinary work or as a roughing pump, a charge of inexpensive pump oil will do fine and last quite a while. However, if you're pumping from a contaminated atmosphere or using the unit as a backing pump in a diffusion system you should use a higher grade of oil and change it regularly.
BTW, if you think $15 a litre is bad, wait 'til you contaminate your $200+ diffusion fluid with an inferior product - that'll *really* make you cry. Been there, done that
Anthony
Moderator
Posts: 2306
From: England
Registered: SEP 2000
posted 04-27-2001 08:24 PM
--------------------------------------------------------------------------------
My pump was empty of oil when I went to use it and it ran fine (I was surprised to find it had no oil). Lacking hydraulic or pump oil I put a load of Dot5 fork oil in.
Seems to work and I've had it pumping for about 45mins continuous so far without any signs of trouble.
10fingers
Frequent Poster
Posts: 411
From: USA
Registered: SEP 2000
posted 04-27-2001 11:48 PM
--------------------------------------------------------------------------------
No, I don't want to use an inferior oil. I had heard awhile back that there is an oil that is used for something else but is cheaper and of the exact same composition as vacuum pump oil.