Flanged ends RF with FF 1

[CADOM]

Dear All,
Do you have any experience with flanged piping ends RF connected to flanged valve ends FF?
I want to connect a wafer check valve (FF ends) to a piping with RF ends.
Is it suitable?
Do you recommend a special rubber gasket/seal in between?
Is there any norm (i.e. ASME) to look at for such exotic connection?
Thanks for your prompt support.

 

[LittleInch]

Normally you want to connect RF to RF and FF to FF. An RF to FF risks breaking or cracking the FF flange due to excess bending moment.

You need therefore to buy an FF flange or machine off the raised face.

FF flanges usually use a full face EPDM gasket or similar.

This is not an "exotic" connection. It is very common especially for cast orion or ductile iron components.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[bcd]

This is a wafer check valve, meaning there is no flange on the valve end. You do not need to worry about the valve. You need to worry about the pipe flange. What material is the pipe flange? If it is a low ductility material such as cast iron, then the valve should also have a flat face. If it is a ductile material such as steel, then you are ok.

Gasket material and size should be what is used on a raised face flange.

 

[LittleInch]

If the wafer check is between two flanges then I agree, but the OP is written strangely - "I want to connect a wafer check valve (FF ends) to a piping with RF ends"

"Connect" implies bolting it to the end of pipe?

"insert" implies in between two RF flanges

A drawing or sketch would help...

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[bcd]

Agree with you LittleInch. Description in the original post is not clear.

A "wafer check valve" is a valve that does not have flanged ends. It is sandwiched between flanges. The ends of wafer check valves are normally designed to mate against raised face flanges. My presumption is that the original post is mixed-up in their understanding and description of the problem.

Anyway, best if they just contact the valve manufacturer for some advice.

 

[CADOM]

Sorry for my poor English, in fact it is to sandwich a wafer check valve between two piping flanges.
The wafer check valve is flat face without any flange while the two piping flanges are raised face.
The wafer check valve is Nickel Aluminum Bronze ASTM B148 but I do not know what is the material of the main pipe.
Is it more clear for you?

 

[LittleInch]

Yes, much better.

Then bcd is correct.

This is perfectly normal. Just use whatever flange material you are comfortable with for a RF flange when you sandwich the valve between the flanges together using longer bolts than normal. The wafer check doesn't care what flange is squeezing it. Think of it like a simple plate of metal. There are no bending forces on the valve.

Many water systems use FF flanges in cast iron or DI so this way they can make one check valve which suits both RF and FF flanges when inserted in between them.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Nick_Gray_88]

BCD is definitely correct there then.
Didn’t you request an IOM from the manufacturer? Wondering what manufacturer it comes from…
A typical recommendation for some systems is if you want a FF wafer dual-plate check to take a lugged valve manufactured from bar so the gasket is compressed between two like flanges and seals effectively.
RF flanges have smaller gaskets because there are high-stresses in the gasket caused by the Bending moments of the RF section whereas FF flanges are low-stress wide sealing face flanges intended for softer materials I.e. bronzes. Both a moot point as B148 C95800 takes both due to the Nickel content in the material making it stronger than other bronzes and brasses.

 

[gerhardl]

Agree with all previous posts.

But the question in my mind is as simple as asking what the wafer valve is fabricated for (producers answer).

This could be from no gasket/gasket as gasket is intergrated as soft material extended over the valve connecting side, to standard gaskets suited to the counterflanges, taking fluid, temperature, pressure cost and service life into consideration.