Working principle of the Plastic Gate Valve: the opening and closing part of the gate valve is the gate plate, the direction of motion of the gate plate is perpendicular to the fluid direction, the PVC Gate Valve can only be fully opened and closed, not adjusted and throttling. The gate has two sealing faces, the most commonly used two sealing faces of the mode gate valve form a wedge, wedge angles vary with the valve parameters, usually 5,2 52'when the medium temperature is not high. The gate plate of the wedge gate valve can be made into a whole, called a rigid gate plate, or a trace deformation gate plate to improve the deviation of the sealing surface angle during processing. This gate plate is called an elastic gate plate.When the CPVC Gate Valve is closed, the sealing surface can be sealed only by the medium pressure, that is, the medium pressure presses the gate sealing surface to the valve seat on the other side to ensure the sealing of the sealing surface, which is the self-sealing. Most of the gate valves are using forced sealing, that is, when the valve is closed, to rely on external force to force the gate plate to the valve seat, to ensure the sealing of the sealing surface. The gate plate of the gate valve with the PVC Rod, called the lift lever gate valve, also called the open lever gate valve. Usually there are trapezoidal threads on the lift rod, through the nut at the top of the valve and the guide groove on the valve body, the rotation movement into a straight movement, that is, the operating torque into the operating thrust. When the PVDF Gate Valve is opened, the passage of the fluid is completely unblocked when the gate lifting height is 1:1 times the height of the valve diameter, but this position cannot be monitored during operation. In actual use, the top of the valve stem is used as a sign, that is, the imopen position, as its full open position. In order to consider the temperature change to lock the phenomenon, usually on the open to the vertex position, and then turn back 1 / 2-1 turn, as the position of the fully open valve position.Therefore, the full opening position of the valve is determined according to the position of the gate, namely the stroke. Some gate valve, the valve rod nut is set on the gate plate, the hand wheel rotation to drive the valve rod rotation, and make the gate plate lift, this valve is called the rotary rod gate valve, or called the dark rod gate valve.
Type of gate valve: according to the sealing surface configuration can be divided into wedge gate valve and parallel gate plate gate valve, wedge gate valve can be divided into: single gate plate type, double gate plate type and elastic gate valve; parallel gate plate gate valve can be divided into single gate plate type and double gate plate type. According to the thread position of the valve rod, it can be divided into open rod gate valve and dark rod gate valve.
Advantages of gate valve:
1. Flow resistance is small. The internal medium channel of the valve body is straight through, and the medium flows in a straight line, and the flow resistance is small.
2. Labor and effort can save time when opening and closing. Compared to the stop valve, because whether the direction is open or closed, the gate movement is perpendicular to the direction of the medium flow.
3. Large height, long opening and closing time. The opening and closing stroke of the gate is large, and the drop is made through the screw.
4. Water hammer phenomenon is not easy to produce. The reason is the long closing time.
5. The medium can flow in any direction on both sides and is easy to install. The PPH Gate Valve channels are symmetrical on both sides.
6. The structure length (the distance between the two connecting ends of the frame housing) is small.
7. Simple body, short structure length, good manufacturing technology, and a wide range of application.
8. Compact structure, good rigid valve rigidity, smooth channel, small flow resistance, sealing surface of stainless steel and carbide, long service life, PFA PTFE Lined Valve, reliable seal. Operation is light and flexible.
Disadvantages of gate valve: sealing surface is easy to cause erosion and abrasion, maintenance is more difficult. The external size is larger, open needs a certain space, open and closing time is long. The structure is more complex.