The inlet pressure reducing valve controls the flow of the medium by controlling the opening of the opening and closing parts in the valve body, reduces the pressure of the medium, and adjusts the opening of the opening and closing part with the help of the pressure behind the valve, so that the pressure behind the valve is kept within a certain range. For example, the valve pressure relief valve for the international famous brand flagship product of the United States Walker WORK, the pressure relief valve by using the media division, mainly divided into water valve, gas valve, steam valve, oil valve; structure division, can be divided into imported piston valve and import diaphragm valve, the first of the two kinds of valve were compared and the difference between the:

1. Imported piston type pressure relief valve

The piston type pressure relief valve combines two valves, guide valves and main valves. The design of the guide valve is similar to that of the direct acting pressure relief valve. The exhaust pressure from the guide valve acts on the piston to enable the piston to open the main valve. If the main valve is large and can not be opened directly, the design will open the main valve with the pressure of the entrance.

The work of the piston type pressure relief valve is controlled by the pressure after the valve. When the pressure sensor detects the increase of the valve pressure indication, the opening of the relief valve decreases. When the pressure of the relief valve is detected, the opening of the relief valve increases, so as to meet the control requirements.

The piston pressure reducing valve must have a certain degree of pressure ratio higher than the system value. Even at the maximum or minimum flow rate, it should be able to respond to positive or reaction control signals. These valves should be selected for the range of useful control, that is, 20% to 80% of the maximum flow. Normally a type or characteristic of an equal ratio. These types of valves themselves have better flow characteristics and flow ranges required for proportional control.

Spring piston pressure relief valve is mainly composed of adjusting spring, diaphragm, piston, valve seat, valve disc and other parts. It is a replacement product of spring film type decompression. The pressure drive valve of the downstream is sensed directly by the piston, and the valve opening is controlled to complete the function of reducing pressure and stabilizing pressure. In the cold and hot water supply system of urban building and high rise building, this product can replace conventional water pipe and save equipment. It can also play the role of pressure reducing and stabilizing in the usual hot and cold water pipe network.

The piston type pressure relief valve is mainly used in gas and steam pipes.

2. Imported film pressure relief valve

The membrane pressure relief valve is suitable for water and non corrosive liquid lines of 0~90 degrees centigrade at working temperature. In the hot and cold water supply and the fire water supply system in the high-rise building, the conventional partition water pipe can be replaced to simplify and save the system equipment and reduce the cost of the project.

In this type of pressure relief valve, the double diaphragm is replaced by the piston in the inner guide pressure relief valve. Increase the area of the diaphragm to open a larger main valve, and in the same pipe size, its capacity than a larger valve piston guide. In addition, the diaphragm is more sensitive to pressure change, and the accuracy can reach +/-1%. Higher accuracy is due to the positioning of the downstream sensing line (the outside of the valve), where the location of the gas or liquid is less turbulent. The pressure relief valve is very flexible, and can use different types of pilot valves (such as pressure valves, temperature valves, air loading valves, solenoid valves, or several valves).

For example, the diaphragm pressure relief valve of Walker WORK in the United States mainly consists of adjusting spring, diaphragm, piston, valve seat, valve disc and other parts. The diaphragm is used to direct the downstream pressure drive valve to control the valve opening to complete the pressure reducing and stabilizing function.

In the cold and hot water supply system of urban building and high rise building, the spring film pressure relief valve can replace the conventional zoning water pipe and save the equipment.

It can also play the role of pressure reducing and stabilizing in the usual hot and cold water pipe network.

The spring film pressure relief valve has smooth pressure regulating and stable pressure, which is suitable for water and non corrosive liquid medium.