Hose & pipe fittings for tools

[heraldcoupe]

Does anyone have experience with pipe and fittings for vacuum applications? I am putting together a vacuum chamber, for de-gassing the liquids I use in making parts, and I need to plumb the pump into the chamber. The chamber itself is a pretty ancient piece of kit for testing aviation instrumentation, and I don't know what the unions are. The pump is new, and though I don't have a spec on the unions, it shouldn't be difficult to identify.

Ideally I'd like to find a one-stop shop where I can buy all the necessary plumbing, but online searching is like looking for a needle in a haystack!

Long shot I know, but if you don't ask......

Cheers,
Bill.

[Bob Bowling]

Depends on the degree of vacuum you are using. All the labs I have ever worked in with bench vacuum were done in standard copper tube with soldered joints. Flexible hoses were thick walled rubber pressure tubing - about 1/4" internal diameter. This amount of vacuum would allow water to boil at room temperature so ought to be about 30mmHg - will that be enough to de-gas your liquids?

[piman]

Hello Bill,

I use RS Components for lots of these sort of odd bits and pieces. They do stock a good range of hydraulic and pneumatic fittings, pipe etc. I gues that pneumatic nylon pipe would do the job?

http://uk.rs-online.com/web/home.html

Alec

[heraldcoupe]

I'm looking at 29.1 inches of mercury, which is the theoretical maximum of my pump. I'm going for rigid lines as far as possible.
I regualry deal with RS bu stupidly never thought of them for this application, thanks!

Cheers,
Bill.

[Clive]

or how about mocal? OK, usually pressure stuff but do they do air brakes and stuff??

[PeterBoltryk]

I've been degassing epoxy resin in a vacuum chamber this week at work.  RS do fittings and copper tube, but I've found a company like Johnson valves (http://www.johnsonvalves.co.uk, no connection) or Pipe Center (sic, also no connection) here in Southampton to be cheaper. (and not sure that RS do 1/4" tube?).  It's worth shopping around becuase these fittings seem to me to be rather expensive.

The fittings I used were Wade compression fittings, for 1/4" O/D copper tube.  Your vacuum chamber could of course use metric tube instead.  If you're trying to fit to existing fittings etc, make sure you check the tube size - 6mm and 1/4" are pretty close but the fittings won't work.. :)   On the other hand, Wade engrave their fittings with the tube diameter, so if your chamber has these then you ought to be able to identify which sytem you need to buy.  

For drawing the epoxy into the mould we use some disposable silicone tube, which allowed you to use a simple clamp to control flow. (e.g. http://www.coleparmer.co.uk/catalog/product_view.asp?sku=0683310).