First, the characteristics and working principle of the piston flow regulating valve
Piston type flow regulating valves are different from butterfly valves and gate valves that are only used for line shut-off. Piston valves are valves that can meet various special adjustment requirements. The adjustment function is realized by an axial movement similar to a piston-like cylinder in the valve chamber, and its stroke is consistent with the direction of water flow in the tube. The water flows from the axial arc into the outer casing, and the flow passage in the piston valve is axisymmetric, and no turbulence occurs when the fluid flows. The change in the flow area is achieved by a linear motion of the piston along the axial direction of the pipe. Regardless of the position of the piston, the flow section in the valve chamber is annular, and the shaft is contracted at the outlet to achieve optimal cavitation prevention, thereby avoiding cavitation caused by throttling to the valve body and the pipe. damage.

Second, the application of piston flow control valve
There are four types of outlet adjustment components:

1. S-type, the closed guide member has a slotted sleeve. It is suitable for the occasions of controlling flow, adjusting the high pressure difference and sufficient back pressure. Its regulation is matched with the fluid state, which can achieve better results.

2, E-type, with a straightening of the curve and a sudden enlargement of the cross section along the downstream end of the end seat, thereby eliminating cavitation damage. It is suitable for the occasions of controlled flow, high pressure difference and large back pressure, while the straightening and straightening of the cross section can reduce the cavitation effect.

3, F type, has a short diffusing tube at the outlet of the valve body, suitable for adjustment and opening and closing occasions, and plays a switching role. The head loss is very small when opening and closing, and the resistance is small when fully opened.

4, LH or SZ type, the pilot part of the piston closed in the valve cavity is equipped with a porous ring net with anti-cavitation, suitable for adjustment, anti-cavitation, high pressure difference, small back pressure (at the entrance of the reservoir), Its control flow regulation characteristics and operating conditions require the best match, thus achieving the elimination of cavitation effects.

5. Piston valve can be used as bleed valve and explosion-proof pipe valve in water diversion. When stored, piston valve LH type and E type can be used as liquid level or pressure regulating valve. In the water delivery piston valve LH type and S type can be used. Used as a flow regulating valve, E type, LH type or SZ type can be used as a purge valve or a filling pipe. In sewage, water treatment, the piston valve can be used as a pump start protection valve, or equipped with special regulating outlet parts. It can be used in the water treatment plant's flow regulating valve. The E-type piston valve can also be used as a sewage treatment plant gas volume regulating valve. In the water supply, the piston valve uses different outlet parts according to the liquid working condition, and is used as a pressure/flow regulating valve, for example. Pipe network pressure balance.

Third, the characteristics of the piston flow control valve
The piston valve body is designed as a whole, with high flow capacity, and the opening degree is linear with the flow rate, which can effectively avoid cavitation and vibration. The inner casing has a streamlined guide rib connected to the outer casing, and the stainless steel piston is reliably guided to slide to prevent tilting or poor running. The end face upstream of the inner casing is spherical, causing the water flow to form a gradual process, and the piston is operated by a crank link mounted in the casing. The piston valve is double-sealed with metal to metal and metal and rubber to achieve two-way bubble-level sealing. Therefore, the sealing system has a long service life and is tightly closed.

Due to the special structure of the piston valve, depending on the operating conditions, the over-water characteristic of the valve can be adjusted by the type of the outlet part of the downstream outlet of the valve (the outlet part can be replaced), so as to meet the requirements of different working conditions and achieve the best. The effect of the flow.