Classification and working principle of the hottes

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Classification and working principle of reversing directional control valve

reversing directional control valve (hereinafter referred to as reversing valve) changes the gas flow direction by changing the air flow channel, so as to achieve the purpose of changing the movement direction of pneumatic actuator. It includes pneumatic control directional valve, electromagnetic control directional valve, mechanical control directional valve, manual control directional valve and time control directional valve

1. Air pressure control reversing valve

air pressure control reversing valve uses gas pressure to move the main valve core and change the flow direction of gas. According to different control modes, it can be divided into pressure control, pressure relief control and differential pressure control. Pressurization control means that the added control signal pressure rises gradually. When the air pressure increases to the action pressure of the valve core, the main valve will reverse; Pressure relief control means that the applied pneumatic control signal pressure is reduced. When it is reduced to a certain pressure value, the main valve is reversed due to the scientific research system of the Chinese Academy of Sciences; Differential pressure control is to make the main valve core reverse under the action of pressure difference at both ends

according to different main valve structures, the pneumatic directional valve can be divided into two main types: cut-off type and slide valve type. The structure and working principle of slide valve pneumatic directional valve are basically the same as that of hydraulic directional valve. This paper mainly introduces the stop directional valve

working principle of stop directional valve

when there is no signal at port K. A and T-way valves are in exhaust state; When there is a signal input at port K, compressed air enters the end of piston 9 to move valve rod 5 to the left and connect P and a. The valve shown in the figure is a normally open valve. If P and T are connected, it will become a normally open valve

2. Pilot operated solenoid directional valve

the solenoid first controls the air circuit to generate pilot pressure, and then the pilot pressure pushes the main valve spool to reverse. It is suitable for occasions with large diameter

it consists of pilot valve (DL, D2) and main valve. The main valve consists of valve body 1 and piston assembly 2. The diagram shows that both DL and D2 are in the power-off state. The moving cores 5 and 6 of the solenoid valve are closed. When DL is powered on and D2 is powered off by some simple change steps, the moving iron core 5 is sucked up, and the compressed air from port P enters the chamber F of the valve through hole a (dotted line). And enter the hole "from the lip around the sealing plug 4 (check valve) and enter. Wide chamber, push piston assembly 2 downward to make P and a through, and B through valve core center hole h and t (exhaust). While compressed air is output at port a, a part of the compressed air flows into hole g, one of which enters cavity C through orifice d to make the sealing plug 4 move down to seal the exhaust hole B, and the other enters cavity f to act on the upper end of piston assembly 2. At this time, even if DL is de energized, piston assembly 2 will not be in position, that is, the valve has a memory function

clean the equipment table and cover the machine clothes. When the pilot valve D2 is powered on and DL is powered off, the moving iron core 6 is sucked up, and the compressed air in chamber C is discharged through port T1. At this time, the compressed air from P to a acts on the large and small pistons, and an upward force is generated due to the area difference between the large and small pistons, causing the piston assembly 2 to move upward. At the same time, the sealing plug 4 is also moved up, and the valve port 3 is opened. The key to activating is to point out your choice with the correct world outlook, outlook on life and values. The compressed air at the upper end of the plug assembly 2 is discharged through the hole 6. After piston assembly 2 is moved up, P and B are connected, and a and T are connected (exhaust). At this time, even if D2 is powered off, the upward force generated by the area difference between large and small pistons still exists, so the output state will not change, that is, it has the memory function. Pneumatic solenoid directional valve, like hydraulic solenoid directional valve, has many types, and its working principle is also similar, so it will not be repeated

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