What is special about ammonia service Globe valves? 1

[stiffler]

Guys,

I am looking at 25mm (1") manual globe valves for use on ammonia.

I have to find 40 or so of these valves for a new build project but I don't know where to start. My client mentioned 2 bolt Ammonia flanges - I have no idea what these are.

Temperature will be ambient, pressure will be <50 bar.

Does anyone know where I can start my enquiries for these beasts?

Also does anyone know what dead man valves are in relation to Globe valves?

Cheers!!

 

[donf]

Stiffler,

I spent some time many years ago in the industrial ammonia refrigeration industy. Two bolt, and four bolt (in larger sizes) tongue and groove type flanges were all we used. A couple of advantages were: contained gasket (blow-out proof) and reduced gasket contact area. As I remember, they performed well. At the time, Vogt and Henry were suppliers.

As I said, it's been many years ago (~40), so it's possible that another type of flanged connection is preferred today.

Also - as info - for NPT connections, we used Expando as the thread sealant.

My understanding of the "deadman" concept is that it relies on an operator (person) to maintain the valve in one position (open or closed), and when released, returns to the other position (closed or open). Common with ball and certain gate valves, but I've not run across a globe valve design. Perhaps your client is referring to a control valve that "fails" (on loss of power or control) in a predetermined position.

donf

 

[stiffler]

Thanks Donf,

I will try these 2 companies, I guess they will be able to advise on what exact infomation I need to get from the client.

The dead-man-handle thing confuses me still. These valves are all manual so it's not fail-close from a signal, as you say, it must be some kind if spring return handle but i don't see how these would work on a linear valve. I wil lkeep investigating but any further help will be appreciated!

Thanks

 

[MechEngNCPE]

I would call flow-tec, they are a good valve manufacturer and would be glad to point you in the right direction.