Butterfly Valve Bi-directional valve installation

[BRIS]

We have a twin 1600mm ductile iron water pipeline that can flow in either direction. Pressure is 11 bar. The pipeline is 100 km long with butterfly isolation valves at 5km intervals

The butterfly valves are installed on flanged spigots cast into the valve chamber wall with a flange adaptor on the downstream (normal direction of flow) side of the valve. In the normal direction of flow the closed valve body is therefore in tension.

If flow is in the opposite direction and the valve is closed the valve body will be in compression.

Is this arrangement (i.e closed valve body in compression) acceptable ?

 

[LittleInch]

On the basis that no one else has offered an opinion, I would have thought that this is OK as the valve is subject to tension and comnpression normally. The sealing capability will be determined by the valve supplier as to whether it has a preferred direction of flow or is bi-directional.

For interest, what exactly do you mean by the donwstream flange being a "flange adaptor". Is this the cause of your concern by not being strong in axial force capacity? A diagram, drawing or sketch would be most useful.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[BRIS]

I mean that one side of the valve is directly bolted to a flanged pipe that is cast into the concrete while the other side is a spigot socket joint that can neither take compression or tension. Therefore when the valve is closed in the reverse flow direction the valve body is in compression rather than in tension.

I do not have any concerns at all with this arrangement but I have got myself in the middle of an argument between the client and his design engineer.

 

[LittleInch]

As it stands with the info provided, I really can't see any problem with this unless the valve is only uni directional, but compression is less of an issue than tension so there it is. I suppose it's hard to prove a negative.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[cvg]

if the spigot socket joint is made properly, it can certainly resist force such that the force in the valve body is transferred through the joint into the pipeline downstream. so whats the problem with that?