Multifunctional pump control valve structure and working principle

Multifunctional pump control valve structure and working principle

I. Multifunctional pump control valve introduction

Multifunctional water pump control valve is a new type of hydraulic control valve. A valve can replace the electric butterfly valve, check valve and water hammer eliminator. It can automatically realize the slow opening when the pump starts, and the fast closing and slow closing when the pump stops, without any electric control, other power and manpower, and without hydraulic device.

The main advantages of multi-function water pump control valve are:

No need for operation control. The water pressure difference before and after the valve when the pump starts and stops is used as the control power, and it has the function of automatic opening and closing with the pump starting and stopping.

The opening and closing process of the valve can effectively prevent accidents caused by the surge pressure wave rise. According to field investigations and actual measurements, the peak value of the surge pressure when the pump stops is within 1.3 times the working pressure.

No need for on-site commissioning, applicable to a wide range of working conditions.

Basic maintenance is not required. As a valve instead of more than three valves, the maintenance workload is greatly reduced.

(5) Small resistance loss. Streamlined wide valve body design, resistance loss reduced by more than 50% compared to similar foreign products. For example, in the economic flow of V = 2m/s for DN200 products, the multi-functional water pump control valve has a loss of 0.7m, while similar foreign products have a loss of 1.5m!

Second, the structure and working principle of multifunctional pump control valve

2.1 Structure

The multifunctional water pump control valve structure is shown in Figure 1, composed of the main valve and external accessories. The main valve includes the valve body, the main valve plate, slow closing valve plate, valve stem, valve seat, and diaphragm controller (including the valve cover, diaphragm seat, diaphragm, and diaphragm pressure plate); external attachments include control valves, filters, evacuation valves, and miniature check valves. Among them, the miniature check valve is a special accessory with a flow restriction hole in its check direction. The installation form is shown in Figure 2.

Working principle

Before the pump starts, the pressure of the valve outlet acts on the main valve plate and the valve is in the closed position. At the same time, the upper chamber of the diaphragm controller is connected with the pressure water, and the lower chamber is connected with the low pressure at the valve inlet.

After the pump starts, the valve inlet pressure gradually increases, while the pressure water slowly enters the lower chamber of the diaphragm controller through the connecting pipe at the valve inlet end, realizing the slow opening of the main valve plate, and the opening speed can be adjusted by the control valve.

When the pump stops, the valve inlet pressure drops, when the flow rate is close to zero, the main valve plate closes quickly under its own gravity. As the pressure at the inlet end of the valve decreases, the pressure water at the outlet end of the valve enters the upper chamber of the diaphragm controller through the connecting pipe, and the water in the lower chamber is pressurized back to the inlet end of the valve through the connecting pipe at the inlet end of the valve, and the slow-closing valve plate closes slowly, and the slow-closing time can be adjusted by the control valve. The fast closing of the main valve plate and the slow closing of the slow closing valve plate conforms to the two-stage closing law, which can effectively eliminate water hammer.

Third, several technical issues

Connection pipe component design

The miniature check valve plays a role in ensuring that the valve opening time is longer than the motor start-up time, allowing the motor to start under light load. It also helps prevent water hammer in the pump due to the rapid valve opening speed. The valve opening time can be adjusted by the control valve based on the working pressure at the site. The control valve can control the water flow speed in and out of the upper and lower chambers of the diaphragm controller, thereby adjusting the slow closing time. The diaphragm controller can be repaired when closed, and the valve can be manually operated to open and close during normal pump operation.

The filter ensures the cleanliness of the water in the upper and lower chambers of the diaphragm controller. As the valve's water flow is reciprocating in and out of the opening process, itself has the function of backwashing, so it can also be used in poor media conditions.

3.2 Valve water hammer elimination characteristics

According to the principle of destructive water hammer, the main factors to reduce water hammer pressure rise are two: (1) minimize the water velocity V to near zero before closing the main valve; (2) close the valve for a time t of 5-10 times the water hammer phase u = 2l / (- pressure wave propagation speed, m/s; l - pipeline length, m), the actual pressure H can be limited to a safe range, thus eliminating the hazards of destructive water hammer.