[TheForge] Fwd: fridge compressor? GONE OT A BIT... :)

[Andy Vida]

"David E. Smucker" wrote:
> 
> While I think that most fridge compressors are too small to supply much air
> for many shop uses -- they do make very good vacuum pumps.  Very useful for
> "woodworkers" using vacuum bags for clamping veneer etc.  Never know what a
> blacksmith my want to use vacuum for.  Now Air Conditioning compressors
> could be of a much larger size.  Still you don't find many scrap AC
> compressors -- while there always seems to be a lot of scrap fridge
> compressors.

	A few years ago I bought up the tool collection from a guy
	named Bill Miller.  Bill was a very cool gentleman (his
	wife Sylvia was also a sweetheart) that used to work for
	RCA as an engineer.  One of the things I got from him was
	a backer pump that RCA Switzerland no longer needed, which
	he had taken home with him many years ago.  Backer pumps 
	are used in the inital evacuation of prototype TV tubes.
	Super high vacuum was attainable, but there was an even
	higher vacuum pump he gave me that had no moving parts.
	I never used it, but I think he called it an "oil immersion
	pump".  It is attached to the tube along with the backer.
	When the backer goes as far as it can, then the immersion
	pump, which is filled with heated oil, is allowed to
	cool.  According to Bill, the vacuum is so high that
	they can literally count the free atoms left in the tube
	and that it's a pretty low number.  I always thought
	that was so cool.