A throttle valve restricts fluid passage to control pressure, temperature, or flow rate within a system. Unlike on/off isolation valves, these are built with internal trim that can withstand high velocity and continuous partial opening without excessive wear. Globe and control valves are typical examples, engineered to profile the flow stream and minimize damage from cavitation or wire drawing.
Pinch back that throttle valve on the discharge line so we don't deadhead the pump while we bring the system up to pressure.
Using a standard isolation valve to throttle flow is a common rookie mistake that leads to rapid seat erosion and permanent leaking.
Also heard as
- throttling valve
Do not mix it up with
- Gate valve: Gate valves are for strict on/off isolation and will suffer severe seat damage if used as a throttle valve.
Related terms
Control valve
A power-operated valve that modulates flow on a controller signal to hold pressure, level, flow or temperature at setpoint.
Globe valve
A linear-motion valve that throttles well because its disc moves straight onto a seat across an S-shaped flow path.
Throttle
To hold a valve partly open on purpose to restrict and regulate flow or pressure.
Wire drawing
Erosion of thin grooves across a valve seat by a high-velocity jet leaking through a tiny gap.
Pinch back
To close a valve partway to cut flow or pressure, without shutting it.