Letdown valve - what is it?
Letdown valve - what is it?
(OP)
I came across mention of a "letdown valve" in a Chem Eng article.
Can someone please tell me the function of a letdown valve?
J.
Can someone please tell me the function of a letdown valve?
J.
J.





RE: Letdown valve - what is it?
For example, a pressure control valve to add 600 psig steam to a 250 psig header to maintain the 250 psig header pressure would commonly be referred to as a let-down valve.
RE: Letdown valve - what is it?
regards
RE: Letdown valve - what is it?
J.
RE: Letdown valve - what is it?
When the turbine is off line, or is not passing enough flow to satisfy the requirements of the lower pressure header, some of the steam is "let down" as opposed to the operation of a "pressure reducing valve", whose function from day one is to reduce pressure from one level to another one.
This is not a cast in concrete definition, but just a connotative use of the term instead of just calling it a pressure reducing valve.
rmw
RE: Letdown valve - what is it?
I'll quote the sentence that sparked my query. It's from an AIChE publication describibg a particular accident at a gas plant.
"..a tag was placed on a faulty letdown valve instructing that a bypass must not be used."
There's nothing extra that explains the valve's purpose or the process fluid. I know that it certainly wasn't steam.
I just wanted to get an understanding of the common meaning of the term.
Thanks all.
J.
RE: Letdown valve - what is it?