Pay attention to the installation and maintenance of control valves

Installation and maintenance of control valves

Hydraulic control valves mainly use the self pressure inside the pipeline to control the movement of the main valve disc through the pressure difference between the upper and lower control chambers. Then, they automatically ensure the safe operation of the pipeline network through bypass pipelines and various types of guide valves. They are widely used in construction, fire protection, water plants, heating, steel, electric, petroleum, chemical and other system pipelines. The pipeline network has a slow opening function, which can solve the problem of traditional manual valve and pump opening with slow closing function. The closing time can be manually adjusted, and the automatic closing can be achieved to eliminate water hammer. It has good sealing performance, and after closing, it can achieve sensitive and reliable dripping without leakage. There is no need for manual operation to prevent loss of control. Throughout the operation of the pipeline network, it works automatically. Epoxy is used inside and outside the valve and all corrosive parts. The detachable valve seat structure with resin powder coating is clever, Easy maintenance and replacement (without the need to dismantle the entire valve), it can be installed vertically or horizontally in the pipeline, and its reliability is not limited. Like other valves, hydraulic control valves still have many functions that need to be understood and developed, such as the development of small-diameter flow control valves, rubber requirements for various hydraulic control valves, spring life, etc., in order to better apply them to engineering. Hydraulic control valves should be installed horizontally. When installed horizontally, the valve cover should be facing upwards. There should be drainage facilities after the pressure reducing valve of the fire water supply system. When the automatic sprinkler fire extinguishing system needs to reduce pressure, the pressure reducing valve should be set in front of the alarm valve (along the direction of water flow), and the pressure reducing valve set together with a single alarm valve can be used without equipment; The pressure reducing valve installed in conjunction with multiple alarm valves should be a factory used pressure reducing valve. The pressure reducing valve used for hot water supply projects should be a hot water type pressure reducing valve.

Hydraulic control valve is a valve for water pressure control, which consists of a main valve and its accompanying pipes, guide valves, needle valves, ball valves, and pressure gauges. According to different usage purposes, functions, and locations, it can be evolved into remote control float valves, pressure reducing valves, slow closing check valves, flow control valves, pressure relief valves, hydraulic electric control valves, etc.

Installation and maintenance of hydraulic control valves

Hydraulic control valves are divided into diaphragm type and piston type, with the same working principle. They are both powered by the upstream and downstream pressure difference ¡÷ P, controlled by a pilot valve to enable hydraulic differential operation of the diaphragm (piston), fully regulated by hydraulic automatic control. The pressure value acting on the bottom of the valve disc and below 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 chamber above the diaphragm (piston) cannot be discharged to the atmosphere or downstream low-pressure area, the pressure value acting above 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 value in the control chamber above the diaphragm (piston) is between the inlet pressure and the outlet pressure, the main valve disc is in a regulating state, and its regulating position depends on the joint control action of the needle valve and the adjustable pilot valve in the conduit system. Adjustable pilot valves can open or close their own small valve ports according to the downstream outlet pressure, thereby changing the pressure value of the control chamber above the diaphragm (piston) and controlling the adjustment position of the square valve disc.

Repair and maintenance of hydraulic control valves

Hydraulic control valve is a type of valve body that uses water to self lubricate, without the need for additional oil lubrication. If the components inside the main valve are damaged, please follow the following instructions for disassembly.

(Note: The commonly consumed damaged products inside the internal valve are the diaphragm and O-ring, with very little damage to other internal components.)

Close the gate valves at the front and rear ends of the main valve first.

Loosen the piping joint screws on the main valve cover, release the pressure inside the valve, and remove all screws, including the necessary copper pipe nuts in the control pipeline.

Remove the valve cover and spring, and take off the shaft core, diaphragm, piston, etc., without damaging the diaphragm.

After removing the above items, check whether the diaphragm and O-ring are damaged; If there is no damage, please do not separate or dispute its internal parts

If damage is found on the diaphragm or O-ring, remove it and replace it with a new diaphragm or O-ring. Thoroughly inspect the valve seat, shaft core, and other components inside the main valve for any damage. If any other debris is found inside the main valve, clean it out and assemble the replaced parts in reverse order to install the main valve. Be careful not to block the valve.