Low cracking pressure check valve 5

[donf]

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

 

[gerhardl]

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

 

[donf]

Gerhardl,

Many thanks (and a star).

I would still welcome other suggestions.

Regards,

Donf

 

[Compositepro]

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.

 

[gerhardl]

.. 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.

 

[moltenmetal]

http://www.circle-seal.com/products/check_valves/100/index.html

These check valves actually work.

 

[iainuts]

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

 

[ApC2Kp]

donf,

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

http://www.checkall.com

http://www.checkvalves.com

 

[donf]

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

 

[unclesyd]

You might want to look at the check valves by Hy-Grade.
I would look at the "T" series.

http://www.hy-grade.com/html/products.html

 

[scalvert]

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.

http://www-dft-valves.com

 

[donf]

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

 

[JimCasey]

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