● The axisymmetric annular channel in line with the flow characteristics has strong flow capacity.

● Solve cavitation problem.

● The medium passing through the valve will form bubbles in the area where the pressure changes and drops. In a stable state, the bubble will burst, and the surrounding water molecules will quickly come to supplement and form an impact. If it breaks on the valve wall and forms an impact force on the valve wall, it will gnaw through the valve wall. This phenomenon is called cavitation. There are two ways to solve cavitation problem in piston type regulating valve.

● a. Fan blade ring: the fan blade ring is composed of evenly distributed guide vanes, which divides the upstream medium flow into multiple small streams, and makes spiral flow under the guidance of the fan blade ring. The medium flow is forced to change the direction of flow, and the bubbles generated are limited in the center of the pipe. The rupture of the unstable bubble is not on the wall of the pipe and valve, so cavitation damage is not produced.

● b. Squirrel cage: the squirrel cage is a cylinder with holes extending from the front of the piston. The holes are symmetrical and evenly distributed. The shape and number of holes depend on the working conditions. When the medium flow passes through the cylindrical squirrel cage orifice, it is divided into several streams of high-speed fluid and ejects to the center of the cage along the radial direction. Therefore, the cavitation is limited in the center of the cage, so the valve and pipeline will not be damaged by cavitation. When the downstream pressure is less than two thirds of the upstream, the design adopts the squirrel cage.

● It has linear adjustment characteristics. The opening of the piston valve is linear with the flow rate, and the adjustment accuracy is high. The flow / pressure deviation is less than ± 5% in the process of adjustment.

● Low noise and low vibration under working conditions. According to the site pressure and flow conditions of customized design, so that the valve will not be in the limit opening operation, so the operating conditions of low noise and vibration.

● Control pressure fluctuation and avoid water hammer. The valve is closed quickly and then slowly, so as to avoid the sudden change of flow and pressure in the process of adjustment and not cause water hammer.

● The opening and closing torque is small. The opening and closing part of the valve is the piston. When the valve is closed, the piston moves in a straight line on the guide rail, which is not subject to the "blind plate force" of the medium, and the opening and closing torque is very small.

● Good sealing performance. The double seal of metal to metal and metal to rubber is adopted to ensure zero leakage.