Shut-off valve

Also known as the intercept valve, it is a compulsory sealing valve, which is a type of truncated valve.

It is divided into three types: flange connection, wire buckle connection, welding connection. my country’s valve “Three Hua Gives” once stipulated that the flow of the deeper valve is all from top to bottom, so it has directionability during installation. The movement form of the valve stem (universal name: dark rod), with a lifting rotation rod type, can be used to control various types of fluid Flow. Therefore, this type of interceptor valve valve is very suitable for cutting or adjustment and reunification. Because the valve stems of this type of valve are relatively short, and they have a very reliable cutting function, and due to the changes in the valve seat passing of the valve petals, the valve petals are proportional, which is very suitable for regulating traffic.

The designed valve is designed to enter low, the purpose is to make the flow resistance small, saving effort when the valve is opened. At the same time, when the valve is closed, the pads between the valve shell and the valve cover and the fillers around the valve stem are not stressed. It can not cause the service life of the medium pressure and temperature for a long time to reduce the probability of leakage. In addition, it can be replaced or added in the state of the valve closure to facilitate maintenance.

Many people think that the cut -off valve is low, but it is not. Under normal circumstances, the deadline valve is low in high, but there are also some special circumstances that the deadline is high and low:

1. High -voltage intercept valve with diameter greater than 100mm

Due to the poor sealing performance of the large diameter valve, the medium pressure acts above the valve flap under the closure of the valve to increase the sealing of the valve.


2. Two interception valves connected in series on the bypass pipeline.

In order to ensure the strictness of the valve during the maintenance cycle, the valve that is often opened and closed is required to be equipped with two series cut -off valves. For the bypass system, the installation effect of this bypass is: ① Balance the pressure on the front and back valve of the main channel, so that it will be convenient and save effort, reduce the wear of the main pipeline valve; , Control the water flow to control the boiler’s boiler water pressure test. The intercept valve in the direction of the medium flow is one valve and the secondary valve, respectively. The unit and the secondary valve are turned off when the unit runtime is closed. Both are directly contacting the medium. In order to prevent the pads between the two valve housing and the valve cover and the fillers around the valve stems have been affected by the medium and temperature for a long time, and the fillers of the valve can be replaced in the operation process. “”.


3. Boiler exhaust, empty cut -off valve

Boiled exhaust and empty cut -off valve are only used during the boiler starting water. The frequency of opening and closing is small, but often caused work quality loss due to poor sealing. To this end “High advances and low out.”


4. Electromagnetic speed broken valve

The function of the electromagnetic speed broken valve is to quickly close and quickly cut off fuel supply. The structure of the electromagnetic speed broken valve is similar to the structure of the deeper valve. If the electromagnetic speed broken valve also enters the work quality from the lower part and flows out of the upper part, the fuel effect is very powerful at the lower part of the electromagnetic speed broken valve. it. Therefore, if the working quality enters the speed broken valve from the lower part, the torque generated by the heavy hammer is less than the fuel pressure. When the speed break valve moves, the fuel cannot be cut off, so it cannot achieve the expected purpose. If the working quality enters the upper part of the speed broken valve, because once the speed break valve is moved, the pressure after the valve is reduced rapidly, and the force of fuel to act on the lower part of the valve flap is quickly reduced to zero. The force formed by the gravity of leverage.

Generally, it is difficult to close the valve when using a low -voltage and high -pressure state. If you use low in high pressure and high -caliber state, the valve pressure is easily deformed and bent by water pressure for a long time, affecting the safety and sealing of the valve; If you choose high advances and low places, you can make a small point for the diameter of the valve stem, and it will also save some cost for manufacturers and users.