Installation of dual isolation valves
Thread Content
Why is the first valve in a common two-valve isolation system a ball valve, and the second one a globe valve? Can’t we use two ball valves? Does a stop valve serve a regulating function?
In common setups, ball valves are used first because they can be opened and closed quickly, serving as a primary means of isolation for valves. Gate valves are used secondly because they provide better sealing when closed, preventing minor leaks and ensuring the safety of the system. Two ball valves will also work, but using globe valves can achieve a better sealing effect. Stop valves are generally not used for regulating flow; they are primarily used to completely shut off or allow fluid to pass through. .
For 2 valves, the one at the front is usually a ball valve, while the one behind it is a throttle globe valve; the main consideration here is preventing internal leakage of the valves. The globe valve allows control over the amount of fluid that is released, which facilitates operation.
The main reason for using a stop valve is that ball valves are too expensive!
Haha, it’s really good indeed
Ball valves are fully open or fully closed, while globe valves can be adjusted between 0-100% open. For all normal discharges, first open the ball valve, then open the stop valve to control the flow rate, which also serves to protect the ball valve. When shutting down the pipeline, close the globe valve first, and then the stop valve.