Ball valve with Male Thread

[rjain1848]

Hello,
I want to use forged ball valve for drain and vent application. Valve is of DN15 & DN20, I am planing to to have Male thread connection by that it can directly get assembled on Threaded Half coupling CL3000. I am worried about ease of availability and the orientation of the valve handle. Can any one suggest me what will be difficulties if I go with Male threaded end connection of the valve.

 

[racookpe1978]

How will you isolate the system, and remove and replace the valve later, if you have to unscrew the valve itself from the pipe with a threaded connection of uncertain final length and final orientation? A threaded connection NEVER screws back together twice at the same length!

 

[LittleInch]

I think you've answered your own question.

"I am worried about ease of availability and the orientation of the valve handle"

That is one of the draw backs of such a system - you can't guarantee how many turns it is going to take to get to pressure tightness. You can never undo it but might not be able to turn it enough to get access.



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

 

[racookpe1978]

What I have had to repair (cut out and reweld) is a threaded pipe stub - where the opposite end is run into a socket welded fitting. That socket weld fitting must be cut out and rewelded if the threaded joint is ever loosened or taken apart, or has to be tightened. The other side of the socket weld joint fitting can be a flange, an elbow, a union (sometimes works - not often), a reducer or a coupling. The looseness of the SW fitting allows limited adjustment of the threaded pipe length, and the rotation of the SW joint lets you make up the threaded connection, then adjust the rotation of the pipe so the instrument or valve points the right way for the actuator or display.

 

[mk3223]

If the level handle is an issue, consider a T-handle or handwheel operation types of ball valve.

 

[zdas04]

Some reason you can't put a hammer union or railroad union upstream of the valve? Then you can make everything up on the bench as tight as your gorilla's are able and then orient the operator however you want.


[bold]David Simpson, PE[/bold]
MuleShoe Engineering

In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. Galileo Galilei, Italian Physicist

 

[rjain1848]

Thanks for the comments, My requirement is to make compact drain assembly from the main Header pipe.
We tried 3 piece socket weld valve with prewelded spool of 100 mm to avoid sealing damage due to weld heat. But the complete assembly is goes more than 200mm and its consuming to much place. Have a look on attachment Which is in my mind. Regarding removal I can remove it by just rotating valve through the threads.
Or is there any other way to get assembly more compact.

 

[bcd]

You can disassemble the 3-piece valve to weld the ends and then reassemble.

 

[mk3223]

It may depend on the process piping design requirement if the threaded connection is allowed in the system. If not, to use a socket valve with a nipple extension which will facilitate the field installation.
If limited by the space, disassemble the 3-piece ball valve to weld the end and then reassemble can be a good option as BCD stated above.

 

[JezFullham]

You can probably get the valve with a butterfly handle.

 

[LittleInch]

I often think this issue about damaging the seals is a bit of an exaggeration.

Sure you need to look at it, but if you open the valve and either wrap the valve in something wet and / or fill the valve to just below the seal location with a damp plug equal to the bore then reduce the heat input to a minimum ( stop welding after one pass - do it in bursts), then you shouldn't get to a situation where you run into trouble.

Or submerge the valve in water open, close the ball (trapping the water) then drain off either end and weld. If it gets really hot then you will see steam coming out the end seal....

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