How to Supply Hot Water with Hydraulic Control Valve?

Hydraulic control valve is a valve used to control water pressure. Hydraulic control valve consists of a main valve and its attached conduit, pilot valve, needle valve, ball valve and pressure gauge. According to different purposes, functions and places of use, the hydraulic control valve can be evolved into pressure reducing valve, check valve, flow control valve, pressure relief valve, etc.

Working Principle of Hydraulic Control Valve

The hydraulic control valve is a valve which uses the medium pressure of the pipeline as the power to open, close and adjust. The pilot valve acts with the change of liquid level and pressure of medium. Because there are many kinds of pilot valves, they can be used individually or in several combinations, thus enabling the main valve to achieve the functions of independent and composite adjustment of water level, water pressure and flow rate. However, the body of main valve is similar to the shut-off valve, and when the valve is fully open, its pressure loss is much greater than that of other valves.

The hydraulic control valves can be divided into two types: diaphragm type and piston type. Their working principle is the same. They are powered by the pressure difference between upstream and downstream. The hydraulic differential operation of diaphragm (piston) is controlled by pilot valve, which is fully regulated by hydraulic automatically, so that the main valve is fully opened or closed or in the regulating state. When the pressure water entering the control room above the diaphragm (piston) is discharged to the atmosphere or the downstream low-pressure area, the pressure value acting on the bottom of the valve disc and under the diaphragm is greater than the pressure value above, so the main valve disc is pushed to the fully open position. When the pressure water entering the control room above the diaphragm (piston) cannot be discharged to the atmosphere or the downstream low-pressure area, the pressure value acting on the diaphragm (piston) is greater than the pressure value below, so the main valve disc will be pressed to the fully closed position. When the pressure in the control room above the diaphragm (piston) is between inlet and outlet pressures, the disc of main valve is in an adjustable state depending on the combined control of the needle valve and the adjustable pilot valve in the conduit system. An adjustable pilot valve can open or close its own small port through the outlet pressure downstream and as it changes, thereby changing the pressure in the control chamber above the diaphragm (piston) and controlling the regulating position of the square valve disc.

How Hydraulic Control Valve Supply Hot Water

If the hot water supply project is constructed by dry pipe circulation mode (semi-circulation mode), the setting requirement of pressure relief valve should be the same as that of cold water project. If the standpipe circulation mode (full circulation mode) is used to construct the hot water supply project, the pressure relief valve should be set up to prevent the hot water circulation from damaging the pressure relief valve, and the pressure of the return water pipes in each zone should be balanced at the junction point.