please tell me the difference between Double block and bleed valve and Double isolation and bleed valve. where and for what application these two valves are used?
Re: DBB Valve vs Double isolation and bleed valve
8 years 1 month ago #6308
Thank you received: 14
The "Double Block and Bleedâ€ is normally used at some point where you need to shut off a line temporarily for some task. You also want this operation to be absolutely safe. So, you install two valves with a short flanged spool piece between the valves. In the spool piece you install a Bleed (a vent valve for gas services or a drain valve for liquid service). To operate this you shut off both line valves and open the Bleed valve.