The plastic gate valve uses a plug-shaped valve disc as its opening and closing element. The sealing surface is either flat or conical, and the valve disc moves linearly along the centerline of the valve seat.
This valve features frictionless opening and closing, helping to reduce the impact of friction between sealing surfaces in traditional valves. Its top-entry design allows for direct online inspection and maintenance of the valve installed in the pipeline, facilitating online inspection and maintenance and reducing plant downtime. Its single-seat design eliminates the safety issues caused by abnormal pressure increases in the valve cavity. Employing a low-torque design, the specially designed valve stem requires only a small handle for opening and closing. The valve uses a wedge-shaped sealing structure, relying on the mechanical force provided by the valve stem to press the ball wedge against the valve seat for sealing. This ensures the valve's sealing performance is unaffected by changes in pipeline pressure differentials, providing good sealing performance under various operating conditions. The sealing surface has a self-cleaning structure; when the ball tilts away from the valve seat, the fluid in the pipeline flows uniformly along the ball's sealing surface at 360°, reducing not only the scouring of the valve seat by high-speed fluid but also flushing away accumulated substances on the sealing surface.
Plastic gate valves have two stem movement types: non-rising stem and rising/rotating stem (opening stem). For valves with a diameter of DN50 or less, the stem is made entirely of plastic; for DN65 and above, it is made of plastic-coated steel.
All its flow-through components are made of plastic, offering high corrosion resistance. The materials used are corrosion-resistant plastics such as FRPP, CPVC, UPVC, PPH, and PVDF. RPP plastic gate valves have a longer structural length than gate valves, but also have higher fluid resistance and less reliable sealing over long-term operation.
