The working principle and movement mode of the gate valve
Addtime：2022-11-30 From： View：493
Introduction:
A gate valve is a type of valve that has a gate plate as its opening and closing component. The movement direction of the gate plate is perpendicular to the flow direction of the fluid. Therefore, a gate valve can only be operated in full open or full closed positions, and cannot be used for regulation or throttling. The gate valve achieves sealing by the contact between the valve seat and the gate plate. Usually, the sealing surfaces are welded with metal materials to enhance wear resistance, such as 1Cr13, STL6, stainless steel, etc. The gate plate can be either rigid or elastic. Depending on the type of gate plate, gate valves are classified as rigid gate valves and elastic gate valves.
Working principle:
The opening and closing element of a gate valve is the gate plate. The movement direction of the gate plate is perpendicular to the flow direction. The gate valve can only be fully opened or fully closed, and cannot be used for regulation or throttling. The gate plate has two sealing surfaces. The most common type of gate valve has two sealing surfaces forming a wedge shape. The wedge angle varies depending on the valve parameters and is usually 5°, or 2°52' when the medium temperature is not high. The gate plate of the wedge gate valve can be made as a single piece, called a rigid gate plate; or it can be made as a gate plate that can undergo slight deformation to improve its processability and compensate for the deviation of the sealing surface angle during processing. This type of gate plate is called an elastic gate plate. When the gate valve is closed, the sealing surfaces can rely solely on the medium pressure to seal, that is, the sealing surfaces are pressed against the other side of the valve seat by the gate plate's sealing surface under the medium pressure to ensure the sealing of the sealing surfaces. This is called self-sealing. Most gate valves use forced sealing, that is, when the valve is closed, an external force is used to forcibly press the gate plate against the valve seat to ensure the sealing of the sealing surfaces. The gate plate of the gate valve moves linearly along the valve stem, called a lift stem gate valve, or a visible stem gate valve. Usually, there are trapezoidal threads on the lift stem, which convert the rotational motion into linear motion through the nut at the top of the valve and the guide groove on the valve body, that is, converting the operating torque into operating thrust. When opening the valve, when the gate plate is lifted to a height equal to the valve diameter, the fluid passage is completely unobstructed. However, during operation, this position cannot be monitored. In actual use, the top point of the valve stem is used as a mark, that is, the position where it cannot be opened further, as its fully open position. To consider the locking phenomenon caused by temperature changes, usually when it reaches the top position, it is rotated back by 1/2 to 1 turn as the fully open valve position. Therefore, the fully open position of the valve is determined by the position of the gate plate, that is, the travel. Some gate valves have the valve stem nut on the gate plate, and the handwheel rotates to drive the valve stem to rotate, thereby lifting the gate plate. This type of valve is called a rotating stem gate valve or a concealed stem gate valve.
Exercise methods:
When a gate valve is closed, the sealing surface can rely solely on the medium pressure to achieve sealing. That is, the sealing surface of the gate plate is pressed against the valve seat on the other side by the medium pressure to ensure the sealing of the sealing surface. This is called self-sealing. Most gate valves adopt forced sealing, that is, when the valve is closed, an external force is used to forcibly press the gate plate against the valve seat to ensure the sealing performance of the sealing surface.
The gate valve has its gate plate moving in a straight line along with the valve stem, and is also called a "visible stem gate valve". Usually, there are trapezoidal threads on the lifting rod, which convert the rotational motion into a linear motion through the nut at the top of the valve and the guide groove on the valve body, thereby converting the operating torque into the operating thrust. When opening the valve, when the gate plate is raised to a height equal to 1:1 of the valve diameter, the fluid passage is completely unobstructed. However, during operation, this position cannot be monitored. In actual use, the top point of the valve stem is used as a reference, that is, the position where it cannot be opened further, as its fully open position. To consider the phenomenon of locking due to temperature changes, usually when the valve stem reaches the top position, it is rotated back by 1/2 to 1 turn as the fully open valve position. Therefore, the fully open position of the valve is determined by the position of the gate plate (i.e., the stroke > ). Some gate valves have the valve stem nut on the gate plate, and the handwheel rotates to drive the valve stem to rotate, thereby lifting the gate plate. This type of valve is called a "rotating rod gate valve" or "hidden stem gate valve".
A gate valve is a type of valve that has a gate plate as its opening and closing component. The movement direction of the gate plate is perpendicular to the flow direction of the fluid. Therefore, a gate valve can only be operated in full open or full closed positions, and cannot be used for regulation or throttling. The gate valve achieves sealing by the contact between the valve seat and the gate plate. Usually, the sealing surfaces are welded with metal materials to enhance wear resistance, such as 1Cr13, STL6, stainless steel, etc. The gate plate can be either rigid or elastic. Depending on the type of gate plate, gate valves are classified as rigid gate valves and elastic gate valves.
Working principle:
The opening and closing element of a gate valve is the gate plate. The movement direction of the gate plate is perpendicular to the flow direction. The gate valve can only be fully opened or fully closed, and cannot be used for regulation or throttling. The gate plate has two sealing surfaces. The most common type of gate valve has two sealing surfaces forming a wedge shape. The wedge angle varies depending on the valve parameters and is usually 5°, or 2°52' when the medium temperature is not high. The gate plate of the wedge gate valve can be made as a single piece, called a rigid gate plate; or it can be made as a gate plate that can undergo slight deformation to improve its processability and compensate for the deviation of the sealing surface angle during processing. This type of gate plate is called an elastic gate plate. When the gate valve is closed, the sealing surfaces can rely solely on the medium pressure to seal, that is, the sealing surfaces are pressed against the other side of the valve seat by the gate plate's sealing surface under the medium pressure to ensure the sealing of the sealing surfaces. This is called self-sealing. Most gate valves use forced sealing, that is, when the valve is closed, an external force is used to forcibly press the gate plate against the valve seat to ensure the sealing of the sealing surfaces. The gate plate of the gate valve moves linearly along the valve stem, called a lift stem gate valve, or a visible stem gate valve. Usually, there are trapezoidal threads on the lift stem, which convert the rotational motion into linear motion through the nut at the top of the valve and the guide groove on the valve body, that is, converting the operating torque into operating thrust. When opening the valve, when the gate plate is lifted to a height equal to the valve diameter, the fluid passage is completely unobstructed. However, during operation, this position cannot be monitored. In actual use, the top point of the valve stem is used as a mark, that is, the position where it cannot be opened further, as its fully open position. To consider the locking phenomenon caused by temperature changes, usually when it reaches the top position, it is rotated back by 1/2 to 1 turn as the fully open valve position. Therefore, the fully open position of the valve is determined by the position of the gate plate, that is, the travel. Some gate valves have the valve stem nut on the gate plate, and the handwheel rotates to drive the valve stem to rotate, thereby lifting the gate plate. This type of valve is called a rotating stem gate valve or a concealed stem gate valve.
Exercise methods:
When a gate valve is closed, the sealing surface can rely solely on the medium pressure to achieve sealing. That is, the sealing surface of the gate plate is pressed against the valve seat on the other side by the medium pressure to ensure the sealing of the sealing surface. This is called self-sealing. Most gate valves adopt forced sealing, that is, when the valve is closed, an external force is used to forcibly press the gate plate against the valve seat to ensure the sealing performance of the sealing surface.
The gate valve has its gate plate moving in a straight line along with the valve stem, and is also called a "visible stem gate valve". Usually, there are trapezoidal threads on the lifting rod, which convert the rotational motion into a linear motion through the nut at the top of the valve and the guide groove on the valve body, thereby converting the operating torque into the operating thrust. When opening the valve, when the gate plate is raised to a height equal to 1:1 of the valve diameter, the fluid passage is completely unobstructed. However, during operation, this position cannot be monitored. In actual use, the top point of the valve stem is used as a reference, that is, the position where it cannot be opened further, as its fully open position. To consider the phenomenon of locking due to temperature changes, usually when the valve stem reaches the top position, it is rotated back by 1/2 to 1 turn as the fully open valve position. Therefore, the fully open position of the valve is determined by the position of the gate plate (i.e., the stroke > ). Some gate valves have the valve stem nut on the gate plate, and the handwheel rotates to drive the valve stem to rotate, thereby lifting the gate plate. This type of valve is called a "rotating rod gate valve" or "hidden stem gate valve".