The opening and closing member of the stop valve (Globe Valve) is a plug-shaped valve flap having a flat or tapered surface, and the valve flap moves linearly along the center line of the fluid. The movement form of the valve stem (general name: dark rod), also has the lifting rotary rod type, (common name: bright rod) cut-off valve is only suitable for full opening and full closing, and adjustment and throttling are not allowed.
The shut-off valve is a forced-sealed valve, so when the valve is closed, pressure must be applied to the valve flap to force the sealing surface to leak. When the medium enters the valve from below the valve flap, the resistance to be overcome by the operating force is the friction between the stem and the packing and the thrust generated by the pressure of the medium. The force of closing the valve is greater than the force of opening the valve, so the valve stem The diameter of the stem should be large, otherwise the valve stem can be bent. In recent years, after the appearance of the self-sealing valve, the medium flow direction of the shut-off valve is changed into the valve chamber from above the valve flap. At this time, under the action of the medium pressure, the force of closing the valve is small, and the force of opening the valve is large, the valve stem is The diameter can be reduced accordingly. At the same time, this type of valve is also tight under the action of the medium. China's valve "three-way to give" has stipulated that the flow of the stop valve, all from top to bottom. This valve should be installed horizontally
When the shut-off valve is opened, the opening height of the valve flap is 25% to 30% of the nominal diameter, and the flow rate has reached the maximum, indicating that the valve has reached the fully open position. Therefore, the full open position of the shutoff valve should be determined by the stroke of the valve flap.
Denture Storage Box,Denture Holder Box,Clear Denture Box
Hongrui Medical Devices Co., Ltd. , http://www.zzcprtrainingmodel.com