Application of hydraulic control valve in building water supply and drainage

The hydraulic control valve is a combination of a main valve and its external needle valve and pilot valve.

The hydraulic control valve is a general term for a series of multi-purpose control and safety valves. Mainly include: 1: remote control float valve; 2: pressure reducing valve; 3: slow closing check valve; 4: pressure relief valve; 5: pressure valve and so on. Their main features are: the use of the medium's own pressure and hydraulic system operation, and automatic control, accurate action, reliable performance, can be widely used in the production and fire water supply system pipeline control and safety.

However, when applying hydraulic control valves in engineering, there are still some misunderstandings, such as the applicable conditions of the valve, the design requirements of the valve, the installation points, etc. To this end, this paper intends to use the CECS standard "Design Rules for the Application of Hydraulic Control Valves" (for review) Based on the manuscript, combined with my experience to explain the above aspects.

1. Key points for design of hydraulic control valve

(1) The hydraulic control valve used in the engineering type is a product that has passed the inspection of the manufacturer and has various complete markings and technical data meeting the requirements.
(2) According to the functional requirements, select the type of valve, and then determine the material of the valve body and sealing part of the valve according to the pipeline medium, temperature, building standards and main requirements of the industry. Commonly used valve body materials are cast iron, copper iron, copper, plastic and so on. Commonly used sealing surfaces and lining materials are copper alloy, plastic, steel, hard alloy, rubber and the like. The body material should match the material of the pipe.
(3) The nominal pressure of the valve is 0.6, 1.0, 1.6, 2.5 and 4.0MPa. The working pressure of the pipeline should be less than the nominal pressure of the valve.
(4) The hydraulic control valve in the project should have sufficient space for management, operation, installation and maintenance, and should meet the requirements of the pipeline for the valve.
(5) When the pipeline is flanged, the flanged hydraulic control valve should be used; when the pipeline is grooved, the grooved hydraulic control valve should be used.
(6) The hydraulic control valve shall be placed on the pipeline in which the medium flows in one direction.
(7) The direction of the arrow on the main valve body of the hydraulic control valve must be consistent with the flow direction of the piping system.
(8) There should be no air blockage or air resistance in the pipe section of the hydraulic control valve. An automatic exhaust valve shall be provided in the gas storage section such as the highest position of the pipe network.
(9) When the valve is installed horizontally, the bonnet and valve stem should face upward. When installing vertically, the bonnet and stem should face outward.
(10) The strength and tightness test should be done before the valve is installed.
(11) The strength and tightness test of the valve shall comply with the following requirements.
A, the strength test pressure of the valve is 1.5 times the nominal pressure;
B. The tightness test pressure of the valve is 1.5 times of the nominal pressure;
C. The test pressure shall remain unchanged for the duration of the test, and there shall be no leakage of the shell packing and the valve sealing surface;
D. The valve test duration is as shown in the above table.

Valve test duration

2, remote control float valve

(1) A liquid level automatic control valve that controls the opening and closing of the main valve by opening and closing the floating ball valve in the control circuit, thereby achieving a valve for setting the liquid level control.

(2) The remote control float group shall consist of the following components (in the direction of water flow)

A, control valve (gate valve or butterfly valve); B, filter; C, remote control float valve.
Note: A. If the medium is clean, the micro filter in the main valve conduit system can be used instead of the pipeline filter.
B. At the installation site, there should be space for removing the filter.
(3) When the water tank (box) of the living, production and fire water supply system has a nominal diameter of 50 mm or more, the remote control float valve should be installed.

(4) The nominal diameter of the remote control float should be the same as the nominal diameter of the pipeline.