What are the working principles and characteristics of hydraulic control valves?
Add time：2022/5/10 15:27:02 Page views：7006
Hydraulic control valve is a general term for water‑service control valves. They were first manufactured in Israel, the Netherlands, Denmark, the United States, Canada and other countries. The hydraulic control valve series includes float control valves, adjustable pressure reducing valves, slow‑closing check valves, flow control valves, pressure relief / pressure sustaining valves, electric valves, pump control valves, differential pressure balancing valves, quick‑closing valves, constant water‑level valves and other products. They are widely applied in pipeline networks for building, fire‑protection, waterworks, transportation, municipal engineering, iron and steel, electric power, petroleum, chemical industry and other systems.
Working Principle of Hydraulic Control Valves
When pressurized water enters the control chamber above the diaphragm (piston) and is discharged to atmosphere or the low‑pressure downstream area, the pressure acting on the bottom of the valve disc and beneath the diaphragm becomes higher than the pressure above. This pushes the main valve disc to the fully‑open position.
When pressurized water enters the control chamber above the diaphragm (piston) and cannot be discharged to atmosphere or the low‑pressure downstream area, the pressure acting above the diaphragm (piston) becomes higher than the pressure below. This presses the main valve disc to the fully‑closed position.
When the pressure inside the upper control chamber of the diaphragm (piston) lies between the inlet pressure and outlet pressure, the main valve disc stays in regulating status. Its regulating position is determined by the combined control of the needle valve and adjustable pilot valve in the pipeline system.
The adjustable pilot valve opens or closes its own small orifice according to variations of downstream outlet pressure. Thereby it changes the pressure inside the control chamber above the diaphragm (piston) and controls the regulating position of the main valve disc.
Characteristics of Hydraulic Control Valves
The valve body adopts full‑bore and streamlined design, featuring low fluid resistance and large flow capacity.
Both internal and external surfaces of valve body and valve cover are coated with epoxy resin powder to prevent corrosion.
Adopting advanced foreign detachable valve seat technology with ingenious structure for convenient maintenance and replacement (no need to remove the whole valve).
Can be installed vertically or horizontally in pipelines at will without compromising reliability.
Joints between valve body, valve cover and piston cylinder adopt dual‑protection of sealing gaskets and sealing rings.
The piston cylinder is equipped with flow‑guide holes to provide proper damping for smoother and more flexible piston movement.
Full‑stainless‑steel piston cylinder, integrated piston and nitrile rubber sealing rings. This complete assembly greatly extends service life.
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