Double Block And Bleed Valve Arrangement

Please give more info. There are "new" gas train valves that eliminate the old block and bleed set up.

But if you give more info I will help you size the valves. Dont forget the gas pressure, pipe size and total capacity of your burner.

Proposal P& ID had 03 valves ( 02 BLOCK & 01 Bleed ), now detaied engg stage ,Trtying to reduce cost by considering the idea of 01 Valve ( Trunion Ball valve )

Its a new set up

regards

JOSE

I don't completely understand your question. A block and bleed gas train consists of two normally closed gas valves and one normally open valve usually solenoid operated. The two normally closed valves are in series while the N.O. is located between the two N.C. valves and piped to atmosphere outside of the equipment room our building. These valves are controlled by the burner control system not manual ball valves. I am only a service person but I do know that the engineer specs this type of burner to meet certain safety requirements. Factory Mutual etc.

Hello, One of the things I build the most of in my pipe fab. shop is burner management valve train skids for industrial boilers and lime kilns. On larger line size we nearly always use FM approved Maxon brand block and bleed(vent) valves that are made for the particular gas that is being used. On smaller line size pilot systems we use the Red Hat brand FM approved solenoid valves in the same double block and bleed arrangement. The block valves are fail close and the vent valve is fail open to guarantee total shut of in case of power failure. I have never used a single valve set up on the industrial gas trains because of the insurance requirements we have to follow. Be careful to check your fire Marshall codes and your insurance requirements before changing this set up. You might be running your system without insurance coverage if not careful.

pipewelder

Mr. Welder sir,

I agree with you completely no one has installed one valve in a large gas train after sometime in the sixties. The "manifolded" double gas train values have approval for even large installations. Some double valves have a pressure sensor in between them that is a real way to save on vent piping and increase safety. Honeywell and Seimens both have good double valves. Seimens has a built in gas regulator for the closest valve to the burner, they track very good.

Mike