Pressure relief valve is throttle by opening and closing parts (discs), medium pressure is reduced, and with the direct effect of valve pressure difference, so that the valve pressure to maintain within a certain range of valves, up to 2013, pressure relief valve has been widely used in various industries, suitable for water, gas and other media pipelines and equipment.

Working principle of pressure reducing valve

1. Direct action of membrane pressure reducing valve.

With the increase of the pressure on the outlet side, the film moves upward, the valve opening decreases, the flow rate increases, the pressure drop increases, and the pressure behind the valve decreases; the pressure on the outlet side decreases, the film moves downward, the valve opening increases, the flow rate decreases, the pressure drop decreases, and the pressure behind the valve increases. The outlet pressure of the valve always keeps constant pressure set by setting adjustment screw.

2. Direct action of bellows type pressure reducing valve.

With the increase of outlet pressure, the bellows move upward, the valve opening decreases, the flow velocity increases, the pressure drop increases, and the pressure behind the valve decreases; the outlet pressure decreases, the bellows move downward, the valve opening increases, the flow velocity decreases, the pressure drop decreases, and the pressure behind the valve increases. The outlet pressure of the valve always keeps constant pressure set by setting adjustment screw.

3. The working principle of pilot piston pressure reducing valve.

Turn the adjusting screw, top open the guide valve disc, and the medium enters the piston from the inlet side. As the piston area is larger than the main valve disc area, the piston moves downward to open the main valve. The pressure of the spring is adjusted by the pressure balance after the valve to change the opening of the guide valve, thereby changing the pressure above the piston and controlling the opening of the main valve disc. Keep the pressure behind the valve constant.

4. The working principle of pilot membrane pressure reducing valve.

The piston is retarded by a thin film and the pressure in the upper cavity of the thin film is controlled by a bypass valve.

5. The working principle of pilot membrane pressure reducing valve.

When the regulating spring is in free state, the main valve and the pilot valve are all closed. When the hand wheel is rotated clockwise, the guide valve diaphragm goes down and the guide valve is jacked. The medium passes through the guide valve to the upper part of the diaphragm and pushes the main valve to open. The medium flows to the outlet. The cylinder enters the lower part of the guide valve diaphragm and the outlet pressure rises to keep balance with the spring force. If the outlet pressure increases, the pilot valve diaphragm moves upward, and the opening of the pilot valve decreases. At the same time, the flow rate of the medium under the main diaphragm decreases, the pressure decreases, the opening of the main valve decreases, and the outlet pressure decreases to reach a new balance, and vice versa.

6. The working principle of combined pressure reducing valve.

The pressure reducing valve is composed of the main valve, the guide valve and the globe valve. When the regulating spring is in the free state, the main valve and the guide valve are closed. Turn the adjusting screw, a medium push open the pilot valve, while entering the chamber 1 and adjusting spring pressure balance, into the main valve rubber membrane chamber 2, is the rubber diaphragm upward, the main valve open, the media flow to the outlet (at this time the cut-off valve opens, keep the chamber 2 moving pressure). The outlet medium is fed back to the upper chamber 3 of the rubber film and the lower chamber 4 of the guide valve. When the outlet pressure increases, the diaphragm of the guide valve moves up, the opening of the guide valve decreases, and the medium pressure of the chamber 1 decreases. At the same time, the pressure of the chamber 2 decreases, the rubber film of the main valve moves down, the opening of the main valve decreases, and the outlet pressure decreases to a new balance. And so is perception.

7. The working principle of lever type pressure reducing valve.

This is a pressure reducing valve that balances the pressure through a heavy hammer on the lever. Its operation principle: when the lever is in free state, the valve seat and valve seat of the double seats are closed. Under the action of inlet pressure, the valve disc is pushed upward to form pressure at the outlet, and the weight is adjusted to convey the required outlet pressure through the balance weight on the lever. When the outlet pressure exceeds a given pressure, due to the medium pressure acting on the upper seat than the force acting on the lower seat, resulting in a certain pressure difference, is the disc moving downward, reducing throttle area, outlet pressure is also reduced, to achieve a new balance (and vice versa).

8. The working principle of the pilot bellows type pressure reducing valve.

Turn the adjusting screw, top open the guide valve disc, and the medium enters the piston from the inlet side. As the piston area is larger than the main valve disc area, the piston moves downward to open the main valve. The pressure of the spring is adjusted by the pressure balance after the valve to change the opening of the guide valve, thereby changing the pressure above the piston and controlling the opening of the main valve disc. Keep the pressure behind the valve constant.