wood pellet machine for wood pellet production line

1, QPF-F50-type pneumatic balance valve, also known as the main pressure reducing valve, used in the pneumatic circuit, the compressed air pressure to adjust the value of the pressure set point is almost constant.

2, the valve is pressure regulating - overflow combination valve. When the outlet pressure is lower than the set pressure, it acts as a pressure regulating valve to increase the pressure to the set pressure. When the outlet pressure is higher than the set pressure, the relief valve acts as a relief valve to reduce the outlet pressure to the set pressure. In order to ensure that the export pressure has always been 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 work at the same time instead of the pressure regulating valve and the relief valve. Compared with the pressure regulating valve and the relief valve provided separately in the pneumatic system, the system simplifies, Compact structure. At the same time, the pressure difference between the pressure regulating valve and the relief valve is also eliminated to ensure that the air pressure in the system can be more accurately regulated and stabilized at the required set pressure value.

4, The valve belongs to the pneumatic pressure relief relief valve with outlet pressure feedback. It is normally closed when no pilot signal is input. When the pilot air compressed air into the B cavity, the valve began to work. The level of the output pressure is controlled by the pressure entering the pilot port CP and the outlet pressure is set by adjusting its pressure. The compressed air entering the control chamber B from port CP pushes the piston together with the spool above it to move axially upwards to overcome the force of the spring 7 and compress it. After the relief valve port (ie, the upper end face) of the valve core 6 is completely contacted with the bottom surface of the valve cover 3, the output and overflow passages are blocked. Pistons continue to move up, the spool will move the valve cover upward along the axial direction, and the valve cover compression spring, the pressure regulator port is opened, the input chamber communicates with the output chamber, compressed air into the cavity through the pressure regulator port into the output Cavity, OUT port output. Compressed air from the output chamber enters the A and C chambers via the 2 gas lines 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 lower side of the piston force is greater than the upper side, the piston moves up, pushing the bonnet 3 up, so that the pressure regulating valve port increased by the pressure regulator valve into the output chamber compression Air flow increases, the pressure of the output chamber will rise. When the pressure in the output chamber reaches the set value, the force on the upper and lower sides of the piston is in equilibrium, the piston stops moving up and the opening of the pressure regulating valve remains unchanged. Output pressure and flow of compressed air output remain stable.

6, when the output pressure is higher than the set pressure, the force on the piston side is greater than the underside, the valve cover and the piston together move down, so that the pressure regulating valve port opening decreases, the pressure regulating valve port into the output chamber When the gas flow rate decreases, the pressure of the gas in the output chamber decreases. If the pressure in the output chamber is still higher than the set value at this time, the piston will continue to move down until the pressure regulator port is fully closed. At this time, the force of the spring 1 on the valve cover no longer acts on the piston through the valve spool, but the rubber cushion on the bottom of the valve cover tightly presses 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 is equal to the set pressure value, the piston stops moving. Pressure is set at this time in the pressure relief valve port and relief valve port closed at the same time, the valve is in static equilibrium outlet pressure.

7, if the output pressure is still higher than the set pressure value, the piston continues to move down, the relief valve port that is the upper end of the valve core and the bottom surface of the valve cover 3 from the output chamber and the overflow chamber is connected, the output cavity gas Relief valve port through the EX port discharge. With the pressure drop in the output chamber, the pressure in chamber C will also decrease at the same time. The pressure on the lower side of the piston is higher than the upper side, so that the piston B and the valve core move up along the axial direction gradually to close the opening of the small relief valve port. When the output pressure reaches the set value, the relief valve mouth and bonnet fully fit the bottom, the output chamber and the overflow chamber between the channel is cut off, overflow stop. At this point, the relief valve port and pressure relief valve port closed at the same time, the valve is stopped in the gas flow static equilibrium. As the pressure on the upper and lower sides of the bonnet is in equilibrium with each other, no matter the pressure in the inlet (IN) fluctuates, the balance of the pressure in the valve can not be affected. Therefore, the outlet pressure can be ensured to be stable at all times. Set value, so that the valve has a good pressure characteristics.