Valves Used in the Chemical Process
Jan 08, 2024
In the chemical industry, valves play a crucial role in controlling the flow of various substances. These valves are designed to withstand harsh chemicals, high temperatures, and extreme pressures. They ensure safety and efficiency in chemical processes by regulating the movement of liquids, gases, and vapors. Valves used in the chemical process include gate valves, globe valves, ball valves, plug valves, plunger valves, butterfly valves and check valves.
Gate valves
Gate valves are widely used in the chemical process industry due to their ability to control the flow of fluids and gases. These valves are designed with a gate-like disc that moves up and down to open or close the valve. The gate is usually made from metal, such as stainless steel or cast iron, which makes it durable and resistant to corrosion. One of the main advantages of gate valves is their ability to provide a good seal when closed. This is crucial in chemical processes where leakage can lead to hazardous situations or contamination. Gate valves also offer low-pressure drop, meaning that they do not restrict the flow of fluid significantly when fully open. Gate valves are commonly used in applications where on-off control is required, such as isolating sections of pipelines or shutting down equipment for maintenance. They are particularly suitable for handling abrasive fluids or slurries since the gate can scrape away any solid particles that may be present.
The fluid does not change the flow direction when flowing through the gate valve. When the gate valve is fully opened, the resistance coefficient is almost the smallest among all valves, and the applicable diameter, pressure and temperature ranges are very wide. Compared with globe valves of the same diameter, its installation size is small, so it is the most commonly used type in chemical production equipment. Gate valves are divided into rising stem gate valves and non rising stem gate valves. The rising stem gate valve is particularly good when used for alternating changing of two or more sets of the same equipment. Its rising stem can indicate the opening and closing of the valve. When the gate valve is half-open, the valve core is prone to vibration, which is only suitable for fully open or fully closed conditions, and not suitable for occasions where flow needs to be adjusted. The gate valve body has grooves, so it is not suitable for fluids containing solid particles. In recent years, gate valves with blowing ports can be used in this situation.
Globe valves
Globe valves are commonly used in the chemical process. These valves have a spherical body with an internal baffle that controls flow by raising or lowering a disc. Globe valves are ideal for applications requiring precise control over fluid flow rates. They are often used in systems where throttling or isolation is necessary. The sealing performance of globe valves is reliable and it is also suitable for adjusting flow. It is usually installed at the pump outlet and upstream of the regulating valve bypass flow meter where the flow needs to be adjusted. The fluid changes flow direction when flowing through the valve core, resulting in a great pressure drop. At the same time, solid matter is easily deposited on the valve seat, so it is not suitable for suspensions. Compared with gate valves of the same diameter, the globe valve is bigger, thus limiting its maximum diameters. Compared with ordinary straight-way valves, Y-type globe valves and angle globe valves have smaller pressure drops, and angle valves also have the function of changing the flow direction. The needle valve is also a type of globe valve. Its valve core is tapered and can be used for adjusting small flow or as a sampling valve.
Plug valves, plunger valves and ball valves
Plug valves, plunger valves, and ball valves are commonly used in the chemical process industry due to their ability to control the flow of fluids. These types of valves play a crucial role in ensuring the safe and efficient operation of chemical plants.
Plug valves are designed with a cylindrical or conical plug that can be rotated within the valve body to control the flow. They are known for their tight shut-off capabilities, making them ideal for applications where leakage prevention is critical. Plug valves are commonly used in processes involving corrosive chemicals or high-pressure systems.
Plunger valves, on the other hand, consist of a piston-like plunger that moves back and forth within a cylinder to regulate fluid flow. They are often used in applications requiring precise control over small flow rates. Plunger valves are particularly suitable for measuring liquids or gases accurately, making them essential in industries such as pharmaceuticals or food processing.
Ball valves used in chemical processes consist of a rotating ball with a hole through its center that allows or restricts fluid flow. They can handle high-pressure applications. Ball valves operate by rotating a ball-shaped disc within the valve body to open or close the flow path. They offer excellent sealing properties and low-pressure drops, making them versatile for various chemical processes. Ball valves are widely used in applications where quick shut-off is required or when dealing with abrasive fluids.
The functions of the three valves are similar, and they are all valves that can be opened and closed quickly. The valve core has transverse openings, allowing liquid to pass through directly with a small pressure drop, making it suitable for suspensions or viscous liquids. The valve core can be designed with an L-shaped or T-shaped channel to become a three-way or four-way valve. The appearance of these valves is regular and it is easy to make jacket valves for situations where heat preservation is required. These types of valves can be easily made into pneumatic or electric valves for remote control. The difference between the three valves is that the working pressure of plunger valves, and ball valves is slightly higher.
Butterfly valves
Butterfly valves have a certain adjustment function, especially suitable for large flow adjustment. Their operating temperatures are limited by the sealing material. Butterfly valves are widely used in the chemical process industry due to their versatility and efficiency. These valves are designed to regulate the flow of fluids, gases, or slurries by using a disc that rotates on a shaft. The disc is positioned perpendicular to the flow direction when fully open and parallel when closed. One of the main advantages of butterfly valves is their compact design, which allows for easy installation and maintenance. They also have a low-pressure drop compared to other types of valves, making them ideal for applications where energy efficiency is crucial. In the chemical process industry, butterfly valves are commonly used for controlling the flow of corrosive or toxic chemicals. The valve's disc can be made from various materials such as stainless steel or lined with special coatings to resist corrosion. This ensures that the valve can withstand harsh chemical environments without compromising its functionality. Furthermore, butterfly valves offer excellent throttling capabilities, allowing precise control over fluid flow rates. This is essential in chemical processes where accurate dosing or mixing of chemicals is required.
Check valves
Check valves are essential components used in the chemical process industry to regulate the flow of fluids and prevent backflow. These valves play a crucial role in maintaining the integrity and efficiency of chemical processes. One of the primary functions of check valves is to prevent reverse flow or backflow. In chemical processes, it is vital to ensure that fluids flow in one direction only, as backflow can lead to contamination, equipment damage, and even accidents. Check valves are designed with a mechanism that allows fluid to flow freely in one direction while preventing any reverse flow. Another important aspect of check valves is their ability to provide tight shut-off when needed. In certain situations, it becomes necessary to stop the flow of fluids completely. Check valves are designed with sealing mechanisms that ensure a tight shut-off when required, preventing any leakage or loss of fluid. Furthermore, check valves also help in reducing pressure fluctuations within a system. They act as pressure relief devices by allowing excess pressure to be released from the system when it exceeds a certain limit. This helps in maintaining optimal operating conditions and prevents damage to equipment due to excessive pressure.
A check valve is a valve used to prevent the reverse flow of fluid. It is generally used to prevent contamination, temperature rise or mechanical damage caused by fluid backflow. There are three commonly used check valves, namely swing check valves, lifting check valves and ball check valves. The swing check valve has a larger diameter than the other two valves and can be installed on horizontal or vertical pipes. When installed on vertical pipes, the fluid should flow from bottom to top. The lifting check valve and ball check valve have smaller diameters and can only be installed on horizontal pipelines. The check valve can only be used to prevent sudden backflow but has poor sealing performance. Therefore, other measures should be taken for materials that are strictly prohibited from mixing. When the inlet of the centrifugal pump is in the suction state, the bottom valve installed at the end of the inlet pipe to keep the liquid in the pump is also a check valve. When the container is open, the bottom valve can be equipped with a strainer.
Diaphragm valves and pinch valves
Diaphragm valves are specifically designed to handle corrosive and abrasive fluids, making them ideal for use in chemical plants. Pinch valves are widely employed in various applications, including controlling the flow of corrosive chemicals, slurries, and abrasive materials.
When these two valves are used, the fluid only contacts the diaphragm or hose without touching other parts of the valve body. They are especially suitable for corrosive fluids or viscous liquids, suspensions, etc. However, their use is limited by the material of the diaphragm or hose.
Gate valves
Gate valves are widely used in the chemical process industry due to their ability to control the flow of fluids and gases. These valves are designed with a gate-like disc that moves up and down to open or close the valve. The gate is usually made from metal, such as stainless steel or cast iron, which makes it durable and resistant to corrosion. One of the main advantages of gate valves is their ability to provide a good seal when closed. This is crucial in chemical processes where leakage can lead to hazardous situations or contamination. Gate valves also offer low-pressure drop, meaning that they do not restrict the flow of fluid significantly when fully open. Gate valves are commonly used in applications where on-off control is required, such as isolating sections of pipelines or shutting down equipment for maintenance. They are particularly suitable for handling abrasive fluids or slurries since the gate can scrape away any solid particles that may be present.
The fluid does not change the flow direction when flowing through the gate valve. When the gate valve is fully opened, the resistance coefficient is almost the smallest among all valves, and the applicable diameter, pressure and temperature ranges are very wide. Compared with globe valves of the same diameter, its installation size is small, so it is the most commonly used type in chemical production equipment. Gate valves are divided into rising stem gate valves and non rising stem gate valves. The rising stem gate valve is particularly good when used for alternating changing of two or more sets of the same equipment. Its rising stem can indicate the opening and closing of the valve. When the gate valve is half-open, the valve core is prone to vibration, which is only suitable for fully open or fully closed conditions, and not suitable for occasions where flow needs to be adjusted. The gate valve body has grooves, so it is not suitable for fluids containing solid particles. In recent years, gate valves with blowing ports can be used in this situation.
Globe valves
Globe valves are commonly used in the chemical process. These valves have a spherical body with an internal baffle that controls flow by raising or lowering a disc. Globe valves are ideal for applications requiring precise control over fluid flow rates. They are often used in systems where throttling or isolation is necessary. The sealing performance of globe valves is reliable and it is also suitable for adjusting flow. It is usually installed at the pump outlet and upstream of the regulating valve bypass flow meter where the flow needs to be adjusted. The fluid changes flow direction when flowing through the valve core, resulting in a great pressure drop. At the same time, solid matter is easily deposited on the valve seat, so it is not suitable for suspensions. Compared with gate valves of the same diameter, the globe valve is bigger, thus limiting its maximum diameters. Compared with ordinary straight-way valves, Y-type globe valves and angle globe valves have smaller pressure drops, and angle valves also have the function of changing the flow direction. The needle valve is also a type of globe valve. Its valve core is tapered and can be used for adjusting small flow or as a sampling valve.
Plug valves, plunger valves and ball valves
Plug valves, plunger valves, and ball valves are commonly used in the chemical process industry due to their ability to control the flow of fluids. These types of valves play a crucial role in ensuring the safe and efficient operation of chemical plants.
Plug valves are designed with a cylindrical or conical plug that can be rotated within the valve body to control the flow. They are known for their tight shut-off capabilities, making them ideal for applications where leakage prevention is critical. Plug valves are commonly used in processes involving corrosive chemicals or high-pressure systems.
Plunger valves, on the other hand, consist of a piston-like plunger that moves back and forth within a cylinder to regulate fluid flow. They are often used in applications requiring precise control over small flow rates. Plunger valves are particularly suitable for measuring liquids or gases accurately, making them essential in industries such as pharmaceuticals or food processing.
Ball valves used in chemical processes consist of a rotating ball with a hole through its center that allows or restricts fluid flow. They can handle high-pressure applications. Ball valves operate by rotating a ball-shaped disc within the valve body to open or close the flow path. They offer excellent sealing properties and low-pressure drops, making them versatile for various chemical processes. Ball valves are widely used in applications where quick shut-off is required or when dealing with abrasive fluids.
The functions of the three valves are similar, and they are all valves that can be opened and closed quickly. The valve core has transverse openings, allowing liquid to pass through directly with a small pressure drop, making it suitable for suspensions or viscous liquids. The valve core can be designed with an L-shaped or T-shaped channel to become a three-way or four-way valve. The appearance of these valves is regular and it is easy to make jacket valves for situations where heat preservation is required. These types of valves can be easily made into pneumatic or electric valves for remote control. The difference between the three valves is that the working pressure of plunger valves, and ball valves is slightly higher.
Butterfly valves
Butterfly valves have a certain adjustment function, especially suitable for large flow adjustment. Their operating temperatures are limited by the sealing material. Butterfly valves are widely used in the chemical process industry due to their versatility and efficiency. These valves are designed to regulate the flow of fluids, gases, or slurries by using a disc that rotates on a shaft. The disc is positioned perpendicular to the flow direction when fully open and parallel when closed. One of the main advantages of butterfly valves is their compact design, which allows for easy installation and maintenance. They also have a low-pressure drop compared to other types of valves, making them ideal for applications where energy efficiency is crucial. In the chemical process industry, butterfly valves are commonly used for controlling the flow of corrosive or toxic chemicals. The valve's disc can be made from various materials such as stainless steel or lined with special coatings to resist corrosion. This ensures that the valve can withstand harsh chemical environments without compromising its functionality. Furthermore, butterfly valves offer excellent throttling capabilities, allowing precise control over fluid flow rates. This is essential in chemical processes where accurate dosing or mixing of chemicals is required.
Check valves
Check valves are essential components used in the chemical process industry to regulate the flow of fluids and prevent backflow. These valves play a crucial role in maintaining the integrity and efficiency of chemical processes. One of the primary functions of check valves is to prevent reverse flow or backflow. In chemical processes, it is vital to ensure that fluids flow in one direction only, as backflow can lead to contamination, equipment damage, and even accidents. Check valves are designed with a mechanism that allows fluid to flow freely in one direction while preventing any reverse flow. Another important aspect of check valves is their ability to provide tight shut-off when needed. In certain situations, it becomes necessary to stop the flow of fluids completely. Check valves are designed with sealing mechanisms that ensure a tight shut-off when required, preventing any leakage or loss of fluid. Furthermore, check valves also help in reducing pressure fluctuations within a system. They act as pressure relief devices by allowing excess pressure to be released from the system when it exceeds a certain limit. This helps in maintaining optimal operating conditions and prevents damage to equipment due to excessive pressure.
A check valve is a valve used to prevent the reverse flow of fluid. It is generally used to prevent contamination, temperature rise or mechanical damage caused by fluid backflow. There are three commonly used check valves, namely swing check valves, lifting check valves and ball check valves. The swing check valve has a larger diameter than the other two valves and can be installed on horizontal or vertical pipes. When installed on vertical pipes, the fluid should flow from bottom to top. The lifting check valve and ball check valve have smaller diameters and can only be installed on horizontal pipelines. The check valve can only be used to prevent sudden backflow but has poor sealing performance. Therefore, other measures should be taken for materials that are strictly prohibited from mixing. When the inlet of the centrifugal pump is in the suction state, the bottom valve installed at the end of the inlet pipe to keep the liquid in the pump is also a check valve. When the container is open, the bottom valve can be equipped with a strainer.
Diaphragm valves and pinch valves
Diaphragm valves are specifically designed to handle corrosive and abrasive fluids, making them ideal for use in chemical plants. Pinch valves are widely employed in various applications, including controlling the flow of corrosive chemicals, slurries, and abrasive materials.
When these two valves are used, the fluid only contacts the diaphragm or hose without touching other parts of the valve body. They are especially suitable for corrosive fluids or viscous liquids, suspensions, etc. However, their use is limited by the material of the diaphragm or hose.
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