Throttling Valve

throttling
choking: the act of suffocating (someone) by constricting the windpipe; "no evidence that the choking was done by the accused"
(throttler) garroter: someone who kills by strangling
Attack or kill (someone) by choking or strangling them
Modulating control as opposed to ON/OFF control.
Control (an engine or vehicle) with a throttle
Reduce the power of an engine or vehicle by use of the throttle

valve
A cylindrical mechanism in a brass instrument that, when depressed or turned, admits air into different sections of tubing and so extends the range of available notes
A membranous fold in a hollow organ or tubular structure, such as a blood vessel or the digestive tract, that maintains the flow of the contents in one direction by closing in response to any pressure from reverse flow
control consisting of a mechanical device for controlling the flow of a fluid
device in a brass wind instrument for varying the length of the air column to alter the pitch of a tone
A device for controlling the passage of fluid through a pipe or duct, esp. an automatic device allowing movement in one direction only
a structure in a hollow organ (like the heart) with a flap to insure one-way flow of fluid through it