Double block and bleed valves
Double block and bleed valves
(OP)
Hi People,
Please could you let me know your opinions or experience on the following task?
I want to install a 12" class 600 Double Block and Bleed system on a natural gas pipeline at the plant inlet. This line is going to be commissioned in 10 months. I want to know what valves type to use as main isolating valves?
Rgds,
Marcell
Please could you let me know your opinions or experience on the following task?
I want to install a 12" class 600 Double Block and Bleed system on a natural gas pipeline at the plant inlet. This line is going to be commissioned in 10 months. I want to know what valves type to use as main isolating valves?
Rgds,
Marcell





RE: Double block and bleed valves
There are several existing threads with more info on double block and bleed setups. Use the search feature to find them if you want more backgound.
jt
RE: Double block and bleed valves
Why gate valves and not ball valves?
RE: Double block and bleed valves
We typically just install an orbit valve at the inlet, or if there is some special sfety issue a Pow r seal or equal true slab gate valve.
RE: Double block and bleed valves
RE: Double block and bleed valves
http://virtualpipeline.spaces.msn.com
RE: Double block and bleed valves
Gate or ball, whatever works for you. I'm used to seeing gate valves in most services, especially on lines over 8" or so.
jt
RE: Double block and bleed valves
http://virtualpipeline.spaces.msn.com
RE: Double block and bleed valves
Depends on your perspective... Emergency block valves maybe (typically motor operated and controlled from the control house), but most of the double block and bleeds I've dealt with are not critical to an emergency shutdown of a refinery unit, just for ordinary isolation purposes. Then again, in the refining world you can hardly spit without hitting a valve. I imagine its a bit different on the pipeline side...
jt
RE: Double block and bleed valves
http://virtualpipeline.spaces.msn.com
RE: Double block and bleed valves
RE: Double block and bleed valves
Dcasto,
Please note the company is not prepared to pay for a WKM gate as the price is 3 times more than a ball. I have seen ball valves as DBB in many gas plants and refineries and am going to convince them using ball valves. Any suggestions, please let me know!
Rgds Marcell
RE: Double block and bleed valves
Remember, if you want economy, you will pay for it.
RE: Double block and bleed valves
RE: Double block and bleed valves
Thanks for your supports.
Please note this DB&B is going to isolate a flowline from the plant inlet and must be piggable. So, I think the option of using gate valve drops out (except WKM Gate valve).
Another option is to use a ball valve with proper trunion mounted ball and trim material. I mean if I use peek as seat insert (whicj is a hard material) and heat treat the 316 SS ball with ENP Overlay in order to increase the hardness of the ball, I think I should be fine.
Any comments is appreciated.
If you are agree with what I suggested, could you help me with some supporting documents, articles?
Regards,
Marcell
RE: Double block and bleed valves