Bray lined butterfly valves

[pohj]

Has any one out there, had any experience with Bray Series 23 PTFE line Butterfly valves in NaOH or KOH service.
I have a concern with bray stem and disk design.

 

[valvesarefun]

What is your concern about the disc and stem design?

 

[pohj]

Bray’s stem and disk design is a three part system, consisting of an upper stem, disk and lower stem. The upper stem and the disk are pressed together during assembly. It’s not clear how the lower stem is connected; I can only assume that the lower stem is pressed in as well. Both lower and upper stem are sealed from the contents of the valve by a Bray’s patented / design “Seal Capsule”.

My concern is with Bray’s “Seal Capsule”. Bray is the only manufacture quoting that has this type seal design. With Amri, Durco and Xomox lined butterfly valves, we are see a consistent design of a one piece stem and disk with an energized stem seal design. The energized sealing systems, uses either bell washer or springs with a Viton “O” rings, etc.

We are in a major plant conversion project, and are preparing to purchase 600 lined butterfly valves of various sizes (3 to 18”). Bray valves are an initially cheaper valve but I’m concern that Bray’s seal system would leak NaOH or KOH through the stem creating a maintenance and safety issues.

 

[valvesarefun]

Pohj,

We manufacture TFE lined butterfly valves and make use of the same system employed by the other manufacturers you mentioned (Amri, Durco and Xomox). It is a good sealing system and has been proven to work well over the years under many different conditions.

The implementation of the "seal capsule" is most likely more about marketing than it is about really and truly making any sort of improvement. Many other manufacturers are now marketing this type of valve, and Bray is trying to set their valve apart from the rest by saying they have this fancy stem seal design.

That said, I honestly cant see any reason why the "seal capsule" wouldnt work well. Essentially it is the same principle (an elastomer energized by a metallic spring) it just has a different appearance to it.

You could always ask them to preform some sort of test to prove their design is either comprable or superior to that of other manufacturers. Alternately, I am sure they did testing during the design phase. You could always ask for the test results. If Bray is not willing to show/prove that their valve is as good or better than the others, I would reccomend sticking with what you know works.

Best Regards,

VRF