Analysis of the principle, application and characteristics of emergency shut-off valve

The emergency shut-off valve is a new high-tech energy-saving and environmentally friendly product. Fire protection applications in modern buildings are increasing. In the course of use, some problems were also found, some of which were construction problems and some of which were design problems. A good product not only has a hard product quality, but also has the characteristics of convenience, quick operation, and convenient maintenance.

How the emergency shut-off valve works

The emergency shut-off valve is one of the hydraulic control valves. It is composed of main valve, throttle valve, pilot valve, pressure gauge and other pipe fittings. When the inlet pressure of the main valve is lower than the pressure set by the pilot valve, the pilot valve is in the open state at this time, the pressure in the upper chamber of the main valve is equal to the outlet pressure of the main valve, and there is a pressure difference between the inlet and the outlet, and the water flows out through the valve port through the outlet. . When the fire pump starts, or the pressure of the variable frequency pump rises and exceeds the set pressure of the pilot valve, the pressure of the control pipe is increased by the main valve inlet and the pilot valve, and the pressure acting on the spring is increased, and the pressure is pressed downward to drive the spool. Move down to close the pilot valve. At this time, the main valve inlet pressure is continuously replenished to the upper chamber of the main valve cover through the throttle valve. Since the downward pressure of the valve flap is greater than the upward thrust, the main valve is closed. The key point to note is that the inlet pressure is less than the set pressure and the valve is always open. The inlet pressure is greater than the set pressure and the valve is closed. Nowadays, many designers mistakenly think that as long as the emergency shut-off valve is installed, it will be closed, and it is wrong to say nothing.

Why use an emergency shut-off valve

Historically, the fire pipe network and the living pipe are two different water supply systems. The two pump sets supply water separately, and the pump house to the building is supplied by a two-way pipe for a long distance. In this way, the construction work of the two-way pipeline is large, the cost of the pipeline material is doubled, and there is also a lot of inconvenience in identifying a certain pipeline during maintenance. Second, the fire-fighting pipeline is not used for many years, it is easy to rust, the pipe wall and the interface are Corrosion thinning, usually do not have no pressure, and in the event of a fire, sudden pressure in the pipeline increases, it is easy to burst, resulting in the fire system can not supply water. Third, Shanghai advocates that pumps pump directly from the municipal pipe network and no longer set up underground water pools. This saves the cost of pool construction while avoiding secondary pollution of the water source. Keeping the water clean and hygienic and ensuring people's healthy water is the most important one.

Problems in the project

1. When the fire pump is started, all emergency shut-off valves are open.

The third problem is that the drainage system of the pump house, the water discharged from the pressure relief valve should be discharged into the fire pool or sewer, and should not be placed in a narrow open ditch.

2. The choice of installation location. So far, most users have placed the emergency shut-off valve installation location in the well. One user set the emergency shut-off valve under the stairs. I think it is more reasonable to put it under the stairs for easy commissioning and maintenance.

3. The tubing should be rinsed clean before it is activated. During the commissioning process, we found that the emergency shut-off valve could not be closed, and the pressure factor was excluded. It was suspected that there was a small stone in the valve body. After inspection, most of the 12 valves had pebbles, and two of them had the lower cavity of the valve body. full. Therefore, the pipeline should be cleaned before installing the emergency shut-off valve to ensure that all valves work properly.

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Label: Emergency shutdown valve principle, application, feature analysis

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