Piping material for process vacuum system

[sfxf]

What is the material we typically use for interior and exterior process vacuum piping (NOT cleaning vacuum)? The vacuum pump is rated at 28" Hg, and the piping should be strong enough to handle 28" Hg. negative pressure.

Does anyone know any reference book for process vacuum system design?

Thank you in advance!

 

[TD2K]

What size lines and materials of construction are you talking about?

Most steel piping is capable of withstanding a full vacuum until you get into the larger diameter, thin wall material. There's been some discussion on this site wrt vacuum rating of large, thin wall pipe, a keyword search should turn something up. Now, if you are talking fiberglass or other composites, all bets are off ;-)

 

[sfxf]

TD2K,

Thank you for reply. I am looking at the possibilities of using copper, stainless steel,carbon steel,or galvanize steel. Stainless steel 304 may be overqualified for this non-cleanroom application. I am not sure PVC is strong enough, and it is not good for exterior installation. Copper may be the best option. Any advice?

Thanks.

 

[INBCPE]

sfxf,

I have two favorite books on industrial vacuum systems. The first is called "Process Vacuum Systems" by Ryans. My copy was printed in 1990, has a silver hard cover, and is about 240 pages long. Pretty decent intro to vacuum systems.

The book I miss the most, though, is "Steam Ejectors for the Process Industry" (or something similar) by a man named Robert Powell or Powers. I rue the day I lent my copy out to someone I barely knew (never saw it again). I don't think they print it any more. Fantastic book, and if I ever find it used somewhere, I'd buy it in a heartbeat.

As for the selection of materials of construction, I specify either all-welded carbon steel, or all-welded stainless. The grade of steel I pick depends on the service conditions. I stay away from CPVC and copper. I only saw copper vacuum lines once, in a Merck plant up in Canada. But then again, I spent my career in the chemical processing industry. An engineer from a pharmaceutical lab might always specify copper. I've used various steels and alloys, glass, cast phenolic pipe, graphite blocks impregnated with phenolic resin, Tefzel-lined cast iron, etc. Bottom line is material choice should be driven by conditions of service.

A couple other tricks: make sure the number of flanges are minimized, and eliminate all low points. Also install plug or ball valves whenever you have a branch if you can afford it. The people maintaining the system will love you for it.

INBCPE

 

[TD2K]

INBCPE, might want to bookmark the following link:

http://half.ebay.com/cat/buy/prod.cgi?cpid=3228439&domain_id=1856&meta_id=1

They don't have it right now but it looks like they've had in the past.

 

[quark]

sfxf!

Generally we use schedule 40 steel pipes for that application (mind you, this is without learning any code on it)and never had a problem. (perhaps that may be redundant)

Where the area of evacuation is to be vacuum breaked afterwards, do use stainless steels (steam sterilisation for example). This will help you reduce contamination.

Regards,