Pressure reducing valve works and schematic

Pressure relief valve working principle - automatic adjustment

ZJY46H pressure reducing valve is a pressure reducing valve that self-adjusts by using water pressure. The working principle of pressure reducing valve is to keep the pressure and flow of the outlet stable when the inlet pressure and flow rate change. It fully implements self-control, simple commissioning and reliable operation.

When the pipeline flow is 0, the pressure reducing valve is fully closed and the pressure behind the valve is maintained at a low pressure (static pressure can be reduced).

Pressure relief valve works

As shown: when P 1   The pressure relief valve's exit first manifests itself as P   2   ±△P   2   Pass the feedback system outlet pipe to the control valve to make P   t   =P k   ±△P   2   ; Thus L changes accordingly, resulting in ± △ P   e   Changes in pressure catheters lead to P   k   The corresponding change, P   t   With P   k   To achieve a new balance, the overflow area H of the main valve changes accordingly.

Therefore, P 1   Change, while the flow through H does not change. P   2   It is always the original low pressure value. When the flow rate changes, the self-regulating valve works as if it were.
 

1, QPF-F50 pneumatic balancing valve, also known as the main pressure reducing valve, used in the pneumatic circuit, the compressed air pressure value is adjusted so that the set pressure value is nearly constant.

2, the valve is a pressure regulator - overflow combination valve. When the outlet pressure is lower than the set pressure, it acts as a pressure regulator to raise the pressure to the set pressure. When the outlet pressure is higher than the set pressure, it acts as a relief valve, causing the outlet pressure to drop to the set pressure. This ensures that the outlet pressure is always stable at the required set pressure.

3, because the valve has the characteristics of pressure regulating valve and relief valve at the same time, it can replace the pressure regulating valve and relief valve at the same time to work, compared to the pressure system valve and relief valve in the gas system, the system is simplified, Compact structure. At the same time, the set pressure difference between the pressure regulator valve and the relief valve is also eliminated, so that the air pressure in the system can be more accurately adjusted and stabilized at the desired set pressure value.

4. The valve is an air-controlled pressure relief and overflow combination valve with feedback pressure from the ore processing equipment manufacturer. When there is no pilot signal input, it is normally closed. When the pilot air compressed air enters the B chamber, this valve begins to operate. The output pressure is controlled by the air pressure entering the pilot port CP, and the outlet pressure is set by adjusting the pressure. Compressed air entering the control chamber B from the port CP pushes the piston along with the spool on it to move axially upwards, overcoming the force of the spring 7 to compress it. When the relief valve port (ie, the upper end surface) of the spool 6 is completely in contact with the bottom surface of the valve cover 3, the output and overflow passages are cut off. The piston continues to move upwards, the valve plug pushes the valve cover upwards in the axial direction, and the spring on the valve cover is compressed, the pressure regulating valve port is opened, the input chamber communicates with the output chamber, and the compressed air in the input chamber enters the output through the pressure regulating port. The cavity is output via the OUT port. The compressed air in the output chamber enters the A chamber and the C chamber through the two air paths on the valve body. The pressure of the gas in the three chambers is the same.

5. When the output pressure is lower than the set value, the force on the lower side of the piston is greater than the upper side, the piston moves upwards, and the valve cover 3 is moved upwards, so that the pressure regulating valve port is enlarged, and the compression valve port enters the compression of the output chamber. As the flow of air increases, the pressure in the output chamber rises. When the pressure in the output chamber reaches the set value, the forces on the upper and lower sides of the piston are in equilibrium, the piston stops moving upwards, and the opening of the pressure regulating valve port remains unchanged. The pressure and flow rate of the output compressed air at the outlet remain stable.

6, when the output pressure is higher than the set pressure, the upper side of the piston force is greater than the lower side, the bonnet and the piston together to move down, so that the opening of the pressure regulator valve opening, through the pressure regulator valve into the output cavity As the flow of gas decreases, the pressure of the gas in the output chamber drops. If the pressure in the output chamber is still higher than the set value, the piston will continue to move to the magnetic separator manufacturer until the pressure regulator valve port is completely closed. At this time, the force of the spring 1 on the valve cover no longer acts on the piston through the valve plug, but instead, the pad on the bottom of the valve cover presses tightly on the pressure regulating valve port, and the passage between the input chamber and the output chamber is cut off. At this point, if the output pressure equals the set pressure value, the piston stops moving. The set pressure at this time is the outlet pressure at the same time when the pressure regulator valve port and the relief valve port are closed and the valve is in the static equilibrium state.

7, if the output pressure is still higher than the set pressure value, the piston continues to move downwards, the relief valve port, that is, the upper end of the valve core is detached from the bottom surface of the valve cover 3, the output chamber communicates with the overflow chamber, the output chamber gas The relief valve exits through the EX port. As the pressure in the output chamber decreases, the pressure in the C chamber also decreases at the same time, and the pressure at the lower side of the piston is higher than the upper side, so that the piston B and the spool move upward in the axial direction and gradually close the opening of the small relief valve port. When the output pressure reaches the set value, the relief valve port and the bottom of the valve cover completely fit together, and the path between the output chamber and the overflow chamber is cut off and the overflow stops. At this time, the overflow valve port and the pressure regulator valve port are closed at the same time, and the valve is in a static equilibrium state where the gas stops flowing. Since the air pressures on the upper and lower sides of the valve cover are balanced with each other, no matter how the pressure of the air inlet (IN) fluctuates, the pressure balance in the valve cannot be influenced, thus ensuring that the outlet pressure is always stable. The set value makes the valve have good pressure characteristics