1. Structural characteristics
Hydraulic control valves are generally divided into diaphragm type and piston type. They work in the same principle. They are composed of a main valve (Fig. 1.2) and its external needle valve, guide valve, conduit and pressure gauge. With different purposes, functions and places of use, it has evolved into remote control floating ball valve, pressure relief valve, slow-closing check valve, flow control valve, pressure relief/holding valve, hydraulic electric control valve, water level valve, pump control valve, emergency shut-off valve, etc.
2. Action Principle
Hydraulic control valves are powered by the pressure difference between upstream and downstream (P), which can be adjusted automatically, so that the main valve disc can be fully opened or closed at the same time, or in a state of regulation.
Fully closed state: When the water pressure at the inlet end of the main valve enters the valve body and control room respectively, and the ball valve outside the main valve closes at the same time, the main valve is in full closed state.
Full-open state: When the external ball valve of the main valve is fully open, when the water pressure in the control room is all discharged into the atmosphere or downstream low pressure zone, the main valve is fully open.
Floating state: adjust the opening of the ball valve outside the main valve to balance the flow of water through the needle valve and the ball valve. At this time, the main valve is in a floating state.