Single Double block and Bleed Valves - Energy Efficient??
Single Double block and Bleed Valves - Energy Efficient??
(OP)
Can a single double block and bleed valve be considered to be energy efficient?
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Single Double block and Bleed Valves - Energy Efficient??
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RE: Single Double block and Bleed Valves - Energy Efficient??
Can you be a little more specific what your concern is?
RE: Single Double block and Bleed Valves - Energy Efficient??
RE: Single Double block and Bleed Valves - Energy Efficient??
RE: Single Double block and Bleed Valves - Energy Efficient??
Given the years of safety history behind the adoption of the double block and bleed safety isolation, I suggest that you abandon your present course of enquiry.
I saw plant down for several days due to an issue that would not have arisen had the original double block system been left in place. Energy savings would not replace the three days lost revenue in 100 years. The cost of parts not installed was, well, negligible.
And on the fourth day, there was a new face in place of the man responsible for the mess.
Bill
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"Why not the best?"
Jimmy Carter
RE: Single Double block and Bleed Valves - Energy Efficient??
The DB&Bs I've seen are two interlocked ball valves with an intervening bleed valve all in a single body small enough to sit in place of a traditional single isolating valve. The isolating valves are sufficiently separate to give you effective two valve isolation.
By retrofitting them in HP air systems, we're now able to achieve both elements of a two-valve isolation scheme at a single location (which is great, because it restricts the amount of the system which has to be taken out of service, and the amount of pipework which gets depressurised and will inevitably leak when subsequently repressurised).
You minimise the risk of having the kind of experience WAROSS had by fitting DB&B's at all the locations previously fitted with single isolation valves. This buys you flexibility at the expense of significant capital outlay. For us, with a complex ringmain system with numerous branches, distributed consumers, storage and supplies and a requirement for damage tolerance and reconfigurability, it really makes sense. I can see simpler systems where you really don't need that flexibility and where the up-front cost of all that extra valvery is never going to be justified.
A.