Performance requirements for throttle valve
　　The range of flow regulation is large and the change of flow pressure difference is smooth;
　　The internal leakage is small, and if there is an external leakage, the external leakage should also be small;

　　Small adjusting torque and sensitive action.
　　There is no difference between the external structure of throttle valve and globe valve, but the shape of their opening and closing parts is different. Most of the opening and closing parts of the throttle valve are cone-shaped and streamlined, through which the flow and pressure can be adjusted by changing the cross-sectional area of the channel. The throttle valve is used to reduce the medium pressure in case of large pressure drop.
　　The flow velocity of the medium between the throttle disc and the valve seat is very high, which causes the surface of these parts to be damaged quickly - the so-called cavitation phenomenon. In order to minimize the impact of cavitation, the valve disc is made of cavitation resistant material (alloy steel) and made into streamline cone with sharp angle of 140-180, which can also make the valve disc have a larger opening height. Throttling under small gap is generally not recommended.