Cut-off valve is divided into three categories: straight-through cut-off valve, right-angle-type cut-off valve and DC-type oblique cut-off valve.
The most obvious advantage is: in the opening and closing process, because the disc in the valve body seals between the friction than the valve smaller, and thus wear-resistant. The opening height is generally only 1/4 of the diameter of the seat channel, so it is much smaller than the gate valve. Usually there is only one sealing surface on the valve body and disc, so the manufacturing process is better and convenient for maintenance.
The selection principle of the cut-off valve is:
1. High-temperature, high-pressure medium pipe or device should choose the cut-off valve. such as thermal power plants, nuclear power plants, petrochemical systems, high temperature, high-pressure pipe on the road.
2. Tube on the road with lax requirements for convection resistance. Where there is little consideration of pressure loss.
3. Small valve can choose needle valve, instrument valve, sampling valve, pressure gauge valve and so on.
4. There is flow regulation or pressure regulation, but the adjustment accuracy is not high, and the pipe diameter is relatively small, such as the nominal path ≤50mm pipe, it is advisable to choose.
5. The small chemical fertilizer and the big chemical fertilizer in the synthesis industrial production should choose the nominal pressure PN160 nominal pressure 16MPa or PN320 nominal pressure 32MPa high pressure angle stop valve or the high pressure angle type globe valve.
6. Alumina Bayer process in the production of silicon removal workshop, easy to coking of the pipeline, the choice of valve body separate type, seat can be removed, cemented carbide sealing pair of DC-type cut-off valve or DC-type cut-off valve.
7. In the city construction water supply, the heating project, the nominal circulation small pipeline, may choose the cut-off valve, the balance valve or the plunger valve, if the nominal path is smaller than the 150mm Tube road.