Reparing Gate Valves without Dismantling Pipe Assembly and Butterfly Fast Shut-off
Reparing Gate Valves without Dismantling Pipe Assembly and Butterfly Fast Shut-off
(OP)
For large chilled-water pipes, dia 200-350mm, what type of isolating valves would you use?
I am aware of the differences between butterfly and gate valves; namely the price, size and weight, but I am concerned that butterfly valves shut-off too quickly (I read that for large valves the last 20% of the quarter turn controls 80% of the flow) so there is a higher chance for a water hammer.
Also, I am aware that gate valves can be repaired without removing it from the pipeline but I am not sure if this means that some repairs can be done without draining the system. If the system still has to be drained, what advantage is there for being able to repair a gate valve with disconnecting from the pipe?
Thanks in advance to all that share information.
I am aware of the differences between butterfly and gate valves; namely the price, size and weight, but I am concerned that butterfly valves shut-off too quickly (I read that for large valves the last 20% of the quarter turn controls 80% of the flow) so there is a higher chance for a water hammer.
Also, I am aware that gate valves can be repaired without removing it from the pipeline but I am not sure if this means that some repairs can be done without draining the system. If the system still has to be drained, what advantage is there for being able to repair a gate valve with disconnecting from the pipe?
Thanks in advance to all that share information.





RE: Reparing Gate Valves without Dismantling Pipe Assembly and Butterfly Fast Shut-off
RE: Reparing Gate Valves without Dismantling Pipe Assembly and Butterfly Fast Shut-off
RE: Reparing Gate Valves without Dismantling Pipe Assembly and Butterfly Fast Shut-off
RE: Reparing Gate Valves without Dismantling Pipe Assembly and Butterfly Fast Shut-off
RE: Reparing Gate Valves without Dismantling Pipe Assembly and Butterfly Fast Shut-off
Other advantages of a modern gate valve over a butterfly valve include the inherent design reliability / durability characteristics of the valve, larger seating surface for greater forgiveness, as well as improved energy consumption. The pumping costs of a butterfly valve, dependent on the assigned flow coefficient of the valves, can be as much as 10X greater. As for throttling, the vast majority of valve applications are simple open and close service. So unless the application is for a modulating service there is no disadvantage ever for a gate valve.