Standard Code

Standard Name

JIS B3372

Pressure reducing valve for compressed ai

JIS B8410

Pressure reducing valve for waterways

GB/T 10868-

Technical specifications for temperature and pressure reducing valves in power plants

GB/T 12244

General conditions for pressure reducing valves

GB/T 12245

Test method for pressure reducing valve Xineng

GT/T 12246

Pilot-operated reducing valves 

GB/T 3656

Water pressure reducing valve

GB/T 3656

Marine air pressure reducing valve

ASTM F1370

Pressure reducing valve for marine water supply system

JB/T 53265

Product quality classification of pilot operated pressure reducing valves

AWWA C511

Pressure reducing and backflow prevention valve assembly

Number

Name

Operational principle

1

Direct acting diaphragm pressure reducing valve

As the outlet pressure increases, the film moves upwards, the valve opening decreases, the flow rate increases, and the pressure drop should be increased. The pressure behind the valve decreases, and the outlet pressure decreases. The film moves downwards, the valve opening increases, the flow rate decreases, the pressure drop decreases, and the pressure behind the valve increases. The outlet pressure behind the valve is always maintained at a constant pressure set by the adjusting screw.

2

Direct acting bellows pressure reducing valve

As the outlet pressure increases, the corrugated pipe moves upwards, the valve opening decreases, the flow rate increases, and the pressure drop should be increased. The pressure behind the valve decreases, and the outlet pressure decreases. The corrugated pipe moves downwards, the valve opening increases, the flow rate decreases, the pressure drop decreases, and the pressure behind the valve increases. The outlet pressure behind the valve is always maintained at a constant pressure set by the adjusting screw.

3

Pilot piston pressure reducing valve

Turn the adjustment screw to open the pilot valve disc, and the medium enters the upper part of the piston from the inlet side. As the piston area is larger than the main valve disc area, it drives the piston to move downwards, causing the main valve to open. The pressure balance adjustment spring after the valve changes the opening of the pilot valve, thereby changing the pressure on the piston and controlling the opening of the main valve disc to maintain a constant pressure behind the valve.

4

Pilot diaphragm pressure reducing valve

The working principle is the same as above. The pressure in the membrane cavity is controlled by a bypass regulating valve.

5

Pilot diaphragm pressure reducing valve

When the adjusting spring is in a free state, both the main valve and the pilot valve are closed. When the handwheel is turned clockwise, the pilot valve diaphragm opens the pilot valve downwards, and the medium flows through the pilot valve to the top of the main diaphragm, thereby pushing the main valve open, causing the main valve to flow towards the outlet. At the same time, the medium enters the lower part of the pilot valve diaphragm, and the outlet pressure rises to maintain balance with the adjusted spring force. If the outlet pressure increases, the pilot valve diaphragm moves upwards and the pilot valve opening decreases. At the same time, the flow rate of the medium below the main diaphragm decreases, the pressure decreases, and the outlet pressure decreases to reach a new equilibrium, and vice versa.

6

Combination pressure reducing valve

The pressure reducing valve consists of a main valve, a pilot valve, and a shut-off valve. When the adjusting spring is in a free state, the main valve and pilot valve are in a closed state. Turn the adjustment screw and push the pilot valve open by the medium. At the same time, enter the rubber film chamber of the main valve to maintain balance with the pressure of the adjustment spring. Enter the rubber film chamber of the main valve, so that the rubber film is upward, the main valve opens, and the medium flows towards the outlet (at this time, the shut-off valve opens, maintaining a certain pressure in the chamber). The outlet medium then feeds back to the chamber above the rubber film and the chamber below the pilot valve. When the outlet pressure increases, the diaphragm of the pilot valve moves upward and the opening of the pilot valve decreases, causing a decrease in the medium pressure in the chamber. At the same time, the pressure in the chamber decreases, and the rubber diaphragm of the main valve moves downward. The opening of the main valve decreases, and the outlet pressure decreases, reaching a new balance; The opposite is also true.

7

Lever type pressure reducing valve

At this point, a pressure reducing valve is used to balance the pressure through the weight on the lever. Its operating principle: When the lever is in a free state, the valve disc and valve seat of the double valve seat are in a closed state. Under the action of import pressure, the valve disc is pushed upwards, and pressure is formed at the outlet end. The balance weight on the lever is used to adjust the important transmission to the required outlet pressure. When the outlet pressure exceeds the given pressure, due to the greater force exerted by the medium pressure on the upper valve seat than on the lower valve seat, a certain pressure difference is formed, causing the valve disc to move downwards, reducing the throttling area, and the outlet pressure also decreases, achieving a new balance; The opposite is also true.

8

Pilot bellows pressure reducing valve

The structural principle is the same as that of a pilot piston type pressure reducing valve.