One. Press the adjustment medium parameter selection valve:
In the production process, in order to make the pressure, flow and other parameters of the medium meet the requirements of the process flow, an adjustment mechanism needs to be installed to adjust the above parameters. The main working principle of the adjustment mechanism is to adjust the above parameters by changing the flow area between the valve flap and the valve flap and the valve seat. These valves are collectively referred to as control valves, which are divided into self-driven control valves, such as pressure reducing valves and pressure-regulating valves, driven by the power of the medium itself. They are driven by leading power (such as electricity, compressed air, and hydraulic power). ) It is called his drive control valve, such as electric control valve, pneumatic control valve and hydraulic control valve.
Two. Press the valve to prevent the back flow of media:
The role of this type of valve is to allow only the medium to flow in one direction and prevent the direction of flow. Normally, this type of valve operates automatically. The valve flap is opened by the fluid pressure flowing in one direction. When the fluid flows in the opposite direction, the fluid pressure and the self-closing flap of the valve flap act on the valve seat to shut off the flow. The check valve belongs to this type of valve, which includes a swing check valve and a lift check valve. The swing check valve has a hinge mechanism, and a flap like a door leans against the inclined seat surface. In order to ensure that the valve flap can reach the proper position of the valve seat face each time, the flap is designed in the hinge mechanism so that the valve flap has sufficient swirling space and the valve flap is in true and full contact with the valve seat. The flaps can be made entirely of metal. They can also be inlaid with leather, rubber, or synthetic coverings, depending on the performance requirements. Swing check valves In the fully open condition, the fluid pressure is almost unimpeded, so the pressure drop through the valve is relatively small. The poppet of the lift check valve seats on the valve seat seal surface on the valve body. In addition to the valve flap can be freely raised and lowered, the rest as the stop valve, the fluid pressure to lift the valve flap from the valve seat sealing surface, the media back to cause the valve flap fall back to the valve seat, and cut off the flow. Depending on the conditions of use, the solenoid valve flap can be a full metal structure, or it can be in the form of a rubber gasket or rubber ring embedded in the valve holder. Like the shutoff valve, the passage of fluid through the lift check valve is also narrow, so the pressure drop through the lift check valve is larger than the swing check valve, and the flow of the swing check valve is limited Very little.
Third, according to the medium off the nature of the use of valves:
1. Gate valve: The gate valve is used as a cut-off medium. When it is fully open, the entire flow is through. At this time, the pressure loss of the medium is minimized. Gate valves are generally suitable for applications that do not require frequent opening and closing and that keep the gate fully open or fully closed. Valves manufactured by Shanghai Xingkai Valves are not suitable for use as regulating or throttling. For high-speed flowing media, the gate can cause vibration of the gate in a partially opened condition, and the vibration may damage the sealing surface of the gate and the valve seat, and the throttling will cause the gate to suffer erosion of the medium. From the structural form, the main difference is the form of the sealing element used. According to the form of the sealing element, the gate valve is often divided into several different types, such as: wedge gate valve, parallel gate valve, parallel double gate gate valve, wedge type double brake gate gate and so on. The most common forms are wedge gate valves and parallel gate valves.
2. The valve stem axis is perpendicular to the valve seat sealing surface. Diaphragm valve stem opening or closing stroke is relatively short, and has a very reliable cutting action, making this valve is very suitable as a medium cut off or adjustment and throttling use. When the valve flap is in the open condition, its valve seat and the valve sealing surface no longer contact with each other, and has a very reliable cutting action, so that the valve is very suitable for cutting or adjusting the medium and throttling the use of . Once the shutoff valve is in the open state, there is no more contact between its seat and the sealing surface of the disc, so its mechanical seal wear is less, because most of the seat and disc of the cutoff valve are easier to repair or replace. It is not necessary to remove the entire valve from the pipeline when sealing the components. This is suitable for the welding of valves and pipelines. The direction of the flow of the trap medium through this type of valve changes, so the flow resistance of the stop valve is higher than other valves.
Commonly used stop valves are the following:
1) Angle-type stop valve: In the angle-type stop valve, the fluid only needs to change the direction once, so that the pressure through this valve is smaller than that of the conventional structure.
2) DC type stop valve: In the direct or Y type globe valve, the flow channel of the valve body is in a diagonal line with the main flow channel, so the damage degree of the flow state is smaller than the conventional stop valve, so the pressure loss through the valve is also corresponding. It's small.
3) Piston stop valve: This type of globe valve is a variant of a conventional globe valve. In this valve, the flap and seat are usually designed based on the plunger principle. The valve flap is ground to connect the plunger to the valve stem, and the seal is achieved by two elastic seals that are placed on the plunger. The two resilient seals of the plug valve are separated by a collar and the seal around the plunger is secured by the load applied by the bonnet nut to the valve cap. The elastomeric seal can be replaced and can be made from a variety of materials. The valve is mainly used for opening or closing, but it is equipped with a special type of plunger or special collar and can also be used to regulate the flow.
3. Butterfly valve: The butterfly plate of the butterfly valve is installed in the diameter direction of the pipe. In the cylindrical channel of the butterfly valve body, the disc is rotated around the axis, and the rotation angle is between 0° and 90°. When the rotation is 90°, the valve is in the fully open state. The butterfly valve is simple in structure, small in size and light in weight, and consists of only a few parts. And only need to rotate 90 degrees to open and close quickly, the operation is simple, at the same time the valve has good fluid control characteristics. When the butterfly valve is in the fully open position, the thickness of the butterfly plate is the only resistance when the medium flows through the valve body, so the pressure drop generated by the valve is very small, so it has better flow control characteristics.
The butterfly valve has two types of seals: elastic seal and metal seal.
Elastic sealing valve, sealing ring can be mounted on the valve body or attached around the butterfly plate. Metal seals can accommodate higher operating temperatures, while elastomeric seals have temperature-restricted defects. If the butterfly valve is required to be used as a flow control, the size and type of the valve are mainly chosen correctly. The structural principle of the butterfly valve is particularly suitable for making large-diameter valves. Butterfly valves are widely used not only in general industries such as petroleum, gas, chemical and water treatment, but also in cooling water systems of thermal power plants.
Commonly used butterfly valves have two kinds of clip-on butterfly valves and flange-type butterfly valves.
The clip-on butterfly valve uses a stud bolt to connect the valve between the two pipe flanges. The plunger valve flanged butterfly valve has a flange on the valve. The upper flanges of the valve are connected to the pipe flange by bolts. .
4. Ball valve: Ball valve is evolved from a plug valve. It has the same 90 degree rotation movement, except that the plug body is a sphere with a circular through hole or passage through its axis. That is, when the ball rotates 90 degrees, it should have a spherical surface at the entrance and exit, thus cutting off the flow. The ball valve only needs to be rotated tightly with a 90 degree rotation and a small torque. The completely equal valve body cavity provides a small, straight flow path for the medium. Shanghai Xingye Valve professional thinks that the ball valve is the most suitable for open and closed use directly, but recent developments have designed the ball valve to use it for throttling and controlling flow. The main characteristics of the ball valve are its compact structure, easy operation and maintenance, suitable for general working medium such as water, solvent, acid and natural gas, and also suitable for working medium with poor working conditions such as oxygen, hydrogen peroxide, methane and ethylene. The ball valve body can be integral or modular.
In the production process, in order to make the pressure, flow and other parameters of the medium meet the requirements of the process flow, an adjustment mechanism needs to be installed to adjust the above parameters. The main working principle of the adjustment mechanism is to adjust the above parameters by changing the flow area between the valve flap and the valve flap and the valve seat. These valves are collectively referred to as control valves, which are divided into self-driven control valves, such as pressure reducing valves and pressure-regulating valves, driven by the power of the medium itself. They are driven by leading power (such as electricity, compressed air, and hydraulic power). ) It is called his drive control valve, such as electric control valve, pneumatic control valve and hydraulic control valve.
Two. Press the valve to prevent the back flow of media:
The role of this type of valve is to allow only the medium to flow in one direction and prevent the direction of flow. Normally, this type of valve operates automatically. The valve flap is opened by the fluid pressure flowing in one direction. When the fluid flows in the opposite direction, the fluid pressure and the self-closing flap of the valve flap act on the valve seat to shut off the flow. The check valve belongs to this type of valve, which includes a swing check valve and a lift check valve. The swing check valve has a hinge mechanism, and a flap like a door leans against the inclined seat surface. In order to ensure that the valve flap can reach the proper position of the valve seat face each time, the flap is designed in the hinge mechanism so that the valve flap has sufficient swirling space and the valve flap is in true and full contact with the valve seat. The flaps can be made entirely of metal. They can also be inlaid with leather, rubber, or synthetic coverings, depending on the performance requirements. Swing check valves In the fully open condition, the fluid pressure is almost unimpeded, so the pressure drop through the valve is relatively small. The poppet of the lift check valve seats on the valve seat seal surface on the valve body. In addition to the valve flap can be freely raised and lowered, the rest as the stop valve, the fluid pressure to lift the valve flap from the valve seat sealing surface, the media back to cause the valve flap fall back to the valve seat, and cut off the flow. Depending on the conditions of use, the solenoid valve flap can be a full metal structure, or it can be in the form of a rubber gasket or rubber ring embedded in the valve holder. Like the shutoff valve, the passage of fluid through the lift check valve is also narrow, so the pressure drop through the lift check valve is larger than the swing check valve, and the flow of the swing check valve is limited Very little.
Third, according to the medium off the nature of the use of valves:
1. Gate valve: The gate valve is used as a cut-off medium. When it is fully open, the entire flow is through. At this time, the pressure loss of the medium is minimized. Gate valves are generally suitable for applications that do not require frequent opening and closing and that keep the gate fully open or fully closed. Valves manufactured by Shanghai Xingkai Valves are not suitable for use as regulating or throttling. For high-speed flowing media, the gate can cause vibration of the gate in a partially opened condition, and the vibration may damage the sealing surface of the gate and the valve seat, and the throttling will cause the gate to suffer erosion of the medium. From the structural form, the main difference is the form of the sealing element used. According to the form of the sealing element, the gate valve is often divided into several different types, such as: wedge gate valve, parallel gate valve, parallel double gate gate valve, wedge type double brake gate gate and so on. The most common forms are wedge gate valves and parallel gate valves.
2. The valve stem axis is perpendicular to the valve seat sealing surface. Diaphragm valve stem opening or closing stroke is relatively short, and has a very reliable cutting action, making this valve is very suitable as a medium cut off or adjustment and throttling use. When the valve flap is in the open condition, its valve seat and the valve sealing surface no longer contact with each other, and has a very reliable cutting action, so that the valve is very suitable for cutting or adjusting the medium and throttling the use of . Once the shutoff valve is in the open state, there is no more contact between its seat and the sealing surface of the disc, so its mechanical seal wear is less, because most of the seat and disc of the cutoff valve are easier to repair or replace. It is not necessary to remove the entire valve from the pipeline when sealing the components. This is suitable for the welding of valves and pipelines. The direction of the flow of the trap medium through this type of valve changes, so the flow resistance of the stop valve is higher than other valves.
Commonly used stop valves are the following:
1) Angle-type stop valve: In the angle-type stop valve, the fluid only needs to change the direction once, so that the pressure through this valve is smaller than that of the conventional structure.
2) DC type stop valve: In the direct or Y type globe valve, the flow channel of the valve body is in a diagonal line with the main flow channel, so the damage degree of the flow state is smaller than the conventional stop valve, so the pressure loss through the valve is also corresponding. It's small.
3) Piston stop valve: This type of globe valve is a variant of a conventional globe valve. In this valve, the flap and seat are usually designed based on the plunger principle. The valve flap is ground to connect the plunger to the valve stem, and the seal is achieved by two elastic seals that are placed on the plunger. The two resilient seals of the plug valve are separated by a collar and the seal around the plunger is secured by the load applied by the bonnet nut to the valve cap. The elastomeric seal can be replaced and can be made from a variety of materials. The valve is mainly used for opening or closing, but it is equipped with a special type of plunger or special collar and can also be used to regulate the flow.
3. Butterfly valve: The butterfly plate of the butterfly valve is installed in the diameter direction of the pipe. In the cylindrical channel of the butterfly valve body, the disc is rotated around the axis, and the rotation angle is between 0° and 90°. When the rotation is 90°, the valve is in the fully open state. The butterfly valve is simple in structure, small in size and light in weight, and consists of only a few parts. And only need to rotate 90 degrees to open and close quickly, the operation is simple, at the same time the valve has good fluid control characteristics. When the butterfly valve is in the fully open position, the thickness of the butterfly plate is the only resistance when the medium flows through the valve body, so the pressure drop generated by the valve is very small, so it has better flow control characteristics.
The butterfly valve has two types of seals: elastic seal and metal seal.
Elastic sealing valve, sealing ring can be mounted on the valve body or attached around the butterfly plate. Metal seals can accommodate higher operating temperatures, while elastomeric seals have temperature-restricted defects. If the butterfly valve is required to be used as a flow control, the size and type of the valve are mainly chosen correctly. The structural principle of the butterfly valve is particularly suitable for making large-diameter valves. Butterfly valves are widely used not only in general industries such as petroleum, gas, chemical and water treatment, but also in cooling water systems of thermal power plants.
Commonly used butterfly valves have two kinds of clip-on butterfly valves and flange-type butterfly valves.
The clip-on butterfly valve uses a stud bolt to connect the valve between the two pipe flanges. The plunger valve flanged butterfly valve has a flange on the valve. The upper flanges of the valve are connected to the pipe flange by bolts. .
4. Ball valve: Ball valve is evolved from a plug valve. It has the same 90 degree rotation movement, except that the plug body is a sphere with a circular through hole or passage through its axis. That is, when the ball rotates 90 degrees, it should have a spherical surface at the entrance and exit, thus cutting off the flow. The ball valve only needs to be rotated tightly with a 90 degree rotation and a small torque. The completely equal valve body cavity provides a small, straight flow path for the medium. Shanghai Xingye Valve professional thinks that the ball valve is the most suitable for open and closed use directly, but recent developments have designed the ball valve to use it for throttling and controlling flow. The main characteristics of the ball valve are its compact structure, easy operation and maintenance, suitable for general working medium such as water, solvent, acid and natural gas, and also suitable for working medium with poor working conditions such as oxygen, hydrogen peroxide, methane and ethylene. The ball valve body can be integral or modular.
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