How to choose a flushing fluid for welch.

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Filippo_Passeri
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How to choose a flushing fluid for welch.

Post by Filippo_Passeri » Sun Sep 03, 2017 12:42 pm

Recently I have acquired an old Welch (probably 1400) vacuum pump, and I suspect it contains dirty oil. So I need to flush it out, but because of my location, I can't acquire any specialised vacuum flushing fluid, so I need to know what the criteria for choosing a suitable flushing fluid are?

Jerry Biehler
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Re: How to choose a flushing fluid for welch.

Post by Jerry Biehler » Sun Sep 03, 2017 11:30 pm

Just change the oil run it and if it gets dirty again just change the oil again.

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Filippo_Passeri
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Re: How to choose a flushing fluid for welch.

Post by Filippo_Passeri » Tue Sep 05, 2017 8:27 am

Where i live, the rated oil for the pump is not localy available and must be shipped for relativly high prices. So i do not want to waste it for cleaning the pump. I am searching for similar enough oils to clean the pump while not damaging it before the rated oil arrives. But because every oil is different i need to know the most important criterias for choosing the oil for the pump cleaning.

ian_krase
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Re: How to choose a flushing fluid for welch.

Post by ian_krase » Tue Sep 05, 2017 8:53 am

I'm pretty sure that most rotary vane pump oils are pretty similar (esp. if the viscosity ratings are known and are similar).

Also, most vacuum vendors sell imitations of other companys oils.


I just buy the cheap oil from the auto parts store.

(Though my pump is unusual in that the manual calls for a higher viscosity oil than most)

Jerry Biehler
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Re: How to choose a flushing fluid for welch.

Post by Jerry Biehler » Tue Sep 05, 2017 10:20 am

Rotary vacuum pump oil is just well refined clear mineral oil between ISO 40 to 68 weight, its usually food grade too. You ought to be able to find something there. You might try amazon.de, supposedly they are doing free shipping to the Czech Republic on orders above 39 euro.

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Dennis P Brown
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Re: How to choose a flushing fluid for welch.

Post by Dennis P Brown » Wed Sep 06, 2017 1:07 pm

Remember, after flushing a pump with oil, a good bit remains so the flushing oil needs to have very similar vacuum and lubrication properties as the regular oil. Using a very inferior oil could lead to issues. Just kept that in mind.

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