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Low cracking pressure check valve
5

Low cracking pressure check valve

Low cracking pressure check valve

(OP)
I'm looking for a source for spring loaded check valves with a cracking pressure less than 5" WC (0.18 psi) for nitrogen service. 316SS/PTFE construction will suffice. Temperature is 0 - 40C. Sizes could range from 1/4" tubing to NPS 2 Cl 150 flanged.

So far the lowest CP I've found is 1/3 psi.

Thanks for any help.

Donf

RE: Low cracking pressure check valve

Suggestion:

Below link to a datasheet from a well renowned disc check producer, Flowserve, Gestra (with variation on other product and material qualities from the same producer), could be a possible match to your question and anyway one of the best possible on the market.

Competitors/other suppliers exist.

Note the difference in cracking pressure depending on size, flow and mounting direction.

http://www.gestra.de/pdf/neu/DBL_818698_00_RK26A_en.pdf

 

RE: Low cracking pressure check valve

(OP)
Gerhardl,

Many thanks (and a star).

I would still welcome other suggestions.

Regards,

Donf

RE: Low cracking pressure check valve

Rubber "duck-bill" and diaphragm check valves have very low cracking pressure. Spring loaded valves generally do not have very low cracking pressure because they also have to seal reliably when upside-down or dirty. I've used free-floating ball checks mounted so the weight of the plastic ball sealed the valve.It was a 2" check-valve in a 1/2" line.   

RE: Low cracking pressure check valve

.. comment to Compositepro : I would not go for your suggestion in this case, both because of the low-temperature requirement, and that nitrogen in my opinion should have a more active closure than gravity alone.

In addition a gravity based ball check-valve is slow, and might under circumstances give higher loss under opening or part opening and/or high pressure peaks when closing.

Cleaned gas free of particles is presumed.

RE: Low cracking pressure check valve

Try Generant also.  They have a wide range of valves that meet your specs.  I've found they're also less expensive and you'll get better service than from Circle Seal.
http://www.generant.com/ckvlv.htm

RE: Low cracking pressure check valve

donf,

Take a look at the Checkall poppet types, as low as 1/8 psi cracking pressure, depending on seat material.

 www.checkall.com
 www.checkvalves.com  

RE: Low cracking pressure check valve

(OP)
To all,

Thanks for your advice.

Compositepro - I'm looking into the duckbill type.

Moltenmetal - the 100 series Circle Seal valve is an excellent recommendation - if I can get it in the right material. Although their website lists 316SS, my local contact says it's only available in brass. I will persue at the factory level.

ianinuts and ApC2KP - I am looking at Generant and Checkall as well.

Again, my sincere appreciation for taking your time to help. And I'm still open for suggestions.

donf

RE: Low cracking pressure check valve

Check out the website below.  They make two different Wafer check valves that can be bulit with spring craking pressures as low as .10 psi.

www-dft-valves.com

RE: Low cracking pressure check valve

(OP)
Scalvert,

Thanks for the DFT link. I've had positive experience with both the product and the company, and will be using their valves on some of my applications.

donf

RE: Low cracking pressure check valve

Slightly diverging: the conservation vents offered by Protectoseal, Groth, Varec, etc are really check valves.  They start with a very light aluminum pallet (disc) and only the weight determines the cracking pressure. There are configurations offered with flanged connections on both ends, and the minimum cracking pressure is about 1/2 oz/in2  

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