Needle valve structure analysis

Needle valve is solid move after pressure does not occur. With a floating ball valve are firmly seat after by media pressure, move the seat occurs, the seal is pressed onto the ball, Needle valve in order to protect the seal. Weekdays with the ball, the lower shaft with bearings, manipulating small torque, useful in high-pressure valve with large diameter. Needle valve characteristic is horizontal, and the flow is upward mobility, so the valve is closed the water pressure on the valve play a significant role in the film is, the higher the pressure the better sealing performance. Needle valve when the valve is working as a plane rotation, need to overcome the friction coefficient between the valves,Instrument needle valve and the impact it's not as big hydraulic valve. But to overcome the friction in the water under the lamination pressure. Was friction between the laminations through practical experiment, several Corfu little force increases.