Butterfly Valve for Ansi 150 A351-CF8 A182-F304 RF Teflon FR Wafer Wheel Gear (Throttle Service)

[eepc]

Hi guys,

Now I am trying to verify/check the vendor drawings related to the butterfly valve mentioned in the topic.
The vendor says the valve supplied for this item is totally the same for the ones with the definition Butterfly Valve for Ansi 150 A351-CF8 A182-F304 RF Teflon FR Wafer Wheel Gear. I think it does not mean anything to them to write throttling service.

When we asked what is the difference between normal butterfly valve and butterfly valve(throttling service) they replied,
- Which we offer is the same as normal valves. When the valve is open , the disc is rotated a quarter turn so that it allows an almost unrestricted passage of the fluid. The valve may also be opened incrementally to throttle flow.
Pls kindly let us know if this is different from your thinking.....

When I examine API 609 (Butterfly Valvesouble Flanged, Lug- and Wafer-Type)it says regarding throttling;

4.8.1 Levers, gear operators, handwheel, and automatic actuators shall be equipped with provisions to prevent movement
of the disc from the desired set position during normal operating conditions. Normal operating conditions include
throttling service when specified by the purchaser.

You can find attached the BOM for valve and the drawings sent by the vendor for throttling services..

What shall I do , approve the drawings or comment on something?

Please help me

http://files.engineering.com/getfil...68d1-47ca-9dd1-0862e52dff36&file=IMG_5635.JPG

http://files.engineering.com/getfil...8798-4472-bfbc-0dc1438d8974&file=IMG_5636.JPG

http://files.engineering.com/getfil...6aa9-46cd-9495-c769614d3e41&file=IMG_5638.JPG

 

[gerhardl]

Time and again you meet specifications, both from purchaser and vendor's side, that tells you everything, except what you need to supply the correct product ! I think this is the case here!

Your job is to ensure that the recommended product actually can perform under the actual, given, applications.

In my experience problems will often arise when descriptions seems detailed, but are based on experience and use of a given brand, and then a new brand is proposed. The description can be far off, lacking the necessary constructional, operational, fluid, flow and pipeline details that are necessary to check the actual performance from a different brand.

For BF valves throttling will be critical if throttled below a given opening, which will vary with small details in the valve geometry. Small openings combined with high flow might give turbulence, cavitation or other problems. In addition any gear operator will have to be of a construction able to support a stable valve position under any forces given by the application.

If the datasheet and technical details is not enough, try to get direct: put down in writing a detailed functional and performance description. Send and ask supplier: please confirm that your product is constructed for (full performance description) and that the factory's guarantee is valid in full for this application.