Service requirements Ask the following questions • Should the valve merely start and stop the flow • Should it regulate (throttle) flow within a preset flow range limit • Should it provide a combination of two functions above • How much through valve leakage can the system tolerate Gate valves will provide tight shutoff but should not be used to regulate flow. Many inexpensive control valves will provide throttling but may not provide shut-tight, e.g., butterfly valves can provide excellent flow control, but may not be bubble tight. It is often not possible to achieve operational needs with a single, standard, off-the-shelf valve. A custom-built valve, or two standard valves in series, may often be required to obtain the desired results.
