Any advantage to having FF flanges on a CS pump?
Any advantage to having FF flanges on a CS pump?
(OP)
I am specifying some pumps for the third train of a plant using the second train pump datsheets as a guide.
For some reason, the engineer for the second stage pumps specified flat faced flanges for a pump out of carbon steel. Piping is also carbon steel. The pump is a little 5 hp Moyno progressive cavity pumping a oil/water mixture. 4" suction and discharge.
Personally, I would have gone with raised faced. Is there any advantage to the flat faced design?
For some reason, the engineer for the second stage pumps specified flat faced flanges for a pump out of carbon steel. Piping is also carbon steel. The pump is a little 5 hp Moyno progressive cavity pumping a oil/water mixture. 4" suction and discharge.
Personally, I would have gone with raised faced. Is there any advantage to the flat faced design?





RE: Any advantage to having FF flanges on a CS pump?
Raised face for Raised face
and
Flat face for Flat face
Now, having said this there will always be the exception. You have not given any infor mation that points to a possible exception so stick with the "Rule"
RE: Any advantage to having FF flanges on a CS pump?
Is there any advantage to using FF with a carbon steel pump and carbon steel FF mating flange?
RE: Any advantage to having FF flanges on a CS pump?
We have some blowers that we purchase with FF flanges. But they have rubber boot expansion joints bolted directly to each flange. The particular expansion joints used are desgined to bolt up to full faces, not raised faces.
Johnny Pellin
RE: Any advantage to having FF flanges on a CS pump?
RE: Any advantage to having FF flanges on a CS pump?
RE: Any advantage to having FF flanges on a CS pump?
RE: Any advantage to having FF flanges on a CS pump?
Using two FF steel flanges has no advantage. In fact, it could reduce the pressure in the face of the gasket (depending in the type of gasket used), thus being more susceptible to leaks.
RE: Any advantage to having FF flanges on a CS pump?
RE: Any advantage to having FF flanges on a CS pump?
You have not stated any of your pressure conditions, but in small piping like 4" at least if the pressures are not very high I'm not sure I see any real performance disadvantage of flat-faced flanges, either.
RE: Any advantage to having FF flanges on a CS pump?
This is covered in the ANSI B16.5 Appendices and repeated in a variety of detail levels by the gasket and in certain cases, the bolt manufacturers. There is also considerable train on the topic in the B & PV section of Eng Tips.
RE: Any advantage to having FF flanges on a CS pump?
Old British standards used to specify flat face flanges, but these have long been superseded by the common PN or ANSI specifications, due to the raised face simply being more reliable and better at sealing.
Not sure if it helps. but hope so !!
RE: Any advantage to having FF flanges on a CS pump?
RE: Any advantage to having FF flanges on a CS pump?