Off valve is shut down parts (disc) moving the valve along the valve seat centerline. According to this mobile form of the valve, the seat through the mouth of the change is directly proportional relationship with the valve stroke. The type of the valve stem to open or close the trip is relatively short, but very reliable cut, due to changes in the valve seat openings and the valve stroke is proportional to the very suitable for flow regulation. Therefore, this type of valve is suitable as a cut or adjust the throttle use. Selection principles are: 1, high temperature, high pressure medium pipe or device should be selected on the cut-off valve. Fire power plants, nuclear power plants, petrochemical system temperature, high pressure pipeline. Pipeline convection resistance to the strict requirements of the pipeline. Consider that the pressure loss is not the place. Three small valves can be selected needle valves, instrument valves, sampling valves, pressure gauge valve. 4, a flow regulator or pressure regulators, but the adjustment less precision, and the pipe diameter is relatively small, such as the nominal pass through the pipeline ≤ 50mm, should use. 5, synthetic industrial production of fertilizers and fertilizer should be selected nominal pressure PN160 nominal pressure 16MPa or PN320 nominal pressure 32MPa high-pressure angle type globe valve or high-pressure angle of the throttle valve. 6 the desilication workshop, in the production of alumina Bayer method easy to coke the pipeline, easy selection of the valve body separate type, the seat can be the place, carbide seal pair of DC type valve or DC throttle. 7, urban construction, water supply, heating engineering, nominal pass through the smaller pipe, can be used to close the balancing valve or piston valve, such as nominal diameter less than 150mm pipeline. The most obvious advantage is: the process of opening and closing the valve between the valve sealing surface friction is smaller than the gate, and therefore wear. The opening height is typically only 1/4 of the diameter of the seat channel, and therefore much smaller than the gate. Usually only one on the valve body and disc sealing surface, and thus manufacturing processes, ease of maintenance. 
 Cut-off valve advantages 
 A simple structure, manufacturing and maintenance more convenient. 
 2, the working stroke is small, open and close a short time. 
 3, good sealing, small friction force between the sealing surface, longer life expectancy. 
 Nominal pressure: PN1.0-25.0Mpa 150Lb-2500Lb The 
 Operating Temperature: -40-600 ° C 
 Nominal diameter: DN 15-600mm 
 Connection type: flanged, threaded, butt welding, socket welding, NPT 
 Material: PVC, ABS, RPP, 304,316,304 L, 316L, WCB, CF3, CF8, CF3M, CF8M, cast steel, ductile iron, forged steel, stainless steel, copper and so on.