Jacketed Plug Valve
Jacketed Plug Valve
Material: Carbon Steel, Stainless Steel
End Type: Flalnged
Suitable Temperature: -29~250℃
What is a jacketed plug valve?
A Jacketed plug valve is a type of valve designed with jackets meant to heat the media being transported to prevent it from crystallizing. These valves use high-temperature steam or oil on the valve body which is used to enhance the heat of the flowing media to keep it at the required state. Some of the media commonly transported through this type of valve are bitumen and liquid sulfur. Jacketed plug valve manufacturers design this valve with a cylindrical or conically shaped plug to control fluid flow. A plug is rotated inside the valve body to help open and close flow of the media. This plug is designed with a hole where fluid flows through when the valve is started. Jacketed plug valves are of simple and compact design and they are relatively cheaper compared to other valves. This valve can be operated manually or automatically.
Components of a jacketed plug valve
Hand lever or handwheel is a component used in manual jacketed plug valves and it is the part where the valve operator applies force to open or close the valve. The handwheel or lever is connected to the valve plug via a shaft component known as the stem.
This is the component used in automatic jacketed plug valves. Its work is to provide the force or torque needed to operate the valve. The actuator is connected to the valve plug through the valve stem.
This is the component used to transmit torque from the handwheel or actuator to the plug. The stem is designed with threads so that when the handwheel/actuator rotates it can as well rotate as it moves vertically upwards or downwards.
This is the part of a jacketed plug valve that is used to start and stop fluid flow. The plug is powered by the valve handwheel or actuator via the stem. The plug is a solid component with a hole or more than one holes at its center. These holes are aligned to the valve ports by rotating the plug through a quarter turn to allow fluid flow.
This is an internal component of a jacketed plug valve placed on the valve body to provide a surface on which the plug rests to prevent fluid leakage when media flow is stopped.
This is an external part of a jacketed plug valve used to house internal parts of the valve. Jacketed plug valve manufacturers produce the valve body using high-strength metallic materials such as carbon steel, stainless steel, and ductile iron among others. The high strength materials ensure the valve body is strong enough against high pressure and high temperature as well as withstand impact from falling objects. The body also contains the valve inlet and outlet ports.
These are components made on the valve body and contain a hot medium to help in heating the media flowing through the valve to maintain the required viscosity.
This is a component used to prevent fluid leakage along the stem.
The gasket is placed between the pipe and the body joint to prevent fluid leakage.
How does a jacketed plug valve work?
Jacketed plug valves operate by turning the handwheel for a quarter turn. This rotation by the handwheel or actuator is transmitted through the stem to the plug. To open the valve, the handwheel or actuator rotates for a quarter turn (90o degrees) in the clockwise direction. This forces the stem to rotate in the same direction as it turns the valve plug. This rotation of the plug forces it to align the plug port to the valve port which then leaves the valve open for fluid flow. The fluid keeps flowing through the jacketed plug valve until when it is closed. To close the valve, the actuator or handwheel rotates in the opposite direction (counterclockwise). This aligns the plug port perpendicular to the fluid flow and thus it blocks any fluid attempting to flow through the valve.
Also, jacketed plug valve manufacturers design this valve for throttling use in which the plug is rotated slightly to make a 45o degree turn. However, when this valve is used for throttling, it results to double pressure drop which reduces efficiency.
Types of jacketed plug valves
Lubricated jacketed plug valves
This is the jacketed plug valve that uses lubricants or sealants to ease operation over a certain range of pressure. A lubricant film is placed between the valve body and the plug to provide a lubricant seal. As such, this valve needs to be lubricated frequently according to the instructions given by the jacketed plug valve manufacturer. The lubricant used should be able to withstand the operating temperature and should not be washed away by the fluid being transported. The lubricant or seal also helps to prevent wear of parts that come into contact as well as prevent corrosion.
Figure: Lubricated jacketed plug valve.
Non-lubricated jacketed plug valve
This is the type of jacketed plug valve that uses a non-metallic elastomeric liner or sleeve in it. The sleeve is inserted into the body cavity. The plug acts as a wedge where it pushes the sleeve on the valve body. Jacketed plug valve manufacturers use this valve to reduce friction between the body and the plug. These valves are advantageous as they need minimal maintenance, unlike the lubricated types. These valves have the advantage of having a tight shut-off and are small in size.
Figure: Non-lubricated jacketed plug valve.
Eccentric jacketed plug valve
This is a jacketed plug valve that is designed to use a half plug. The plug is used in applications that need higher seating force and minimal friction force from the open to the closed position. This design results in improved shut-off capabilities. This valve is meant to control media flow as well as isolate it where necessary.
Figure: Eccentric jacketed plug valve.
Expanding jacketed plug valve
This is a jacketed plug valve designed to use various components that allow the valve to expand mechanically. Jacketed plug valve manufacturers employ mechanisms that turn around the open and closed position and shield seals from the media flow path. During the time of turning, there is no contact between the seals and the body. Slips used in this valve expand onto the seat when the valve is closed eliminating any wear or abrasion on the seals.
Figure: Expanding jacketed plug valve.
Multiport jacketed plug valve
This is a jacketed plug valve that is used in the transportation and diversion of media. Jacketed plug valve manufacturers design this valve to help reduce the cost of buying several shut-off valves since a single multi-port plug valve will complete the work. However, there are cases in which this valve may not shut off media flow completely. As such, a lot of care should be taken when specifying the port arrangement to enhance the right valve operation.
Figure: Multiport jacketed plug valve.
Automatic jacketed plug valves
This is the version of the jacketed plug valve that is operated using actuators. This valve is convenient for use as it does not need a valve operator to provide the torque needed to start and stop. This type of valve is also the solution in case the valve operation needs a lot of torque and frequent operation.
Jacketed plug valve manufacturers design this valve to use three types of actuators which are hydraulic, pneumatic, and electric actuators. The hydraulic actuator uses hydraulic fluid to generate the torque needed to open the valve. This type of actuator is very powerful relative to other valves due to the use of hydraulic fluid which is incompressible. The pneumatic actuator employs compressed air to turn the valve stem to open/close the valve. This type of actuator is suitable for use in applications where high levels of hygiene are demanded since the air to be used can be filtered. The electric actuator uses electrical energy to operate the valve. This type of actuator converts electrical energy to mechanical energy. This mechanical energy is in terms of torque which when applied to the valve stem the valve opens or closes as necessary.
Figure: Automatic jacketed plug valve.
Applications of jacketed plug valve
- Jacketed plug valves are used in food processing industries.
- They are used in fertilizer manufacturing industries.
- These valves are used in the transportation of molten sulfur or liquid sulfur.
- Jacketed plug valves are used in bitumen processing plants.
- They are used in the processing of coal tar.
- Jacketed plug valves are used in other highly viscous media to ensure they are transported at the required viscosity.
Advantages of jacketed plug valves
- These valves are versatile as they are suitable for use in wide areas of industries.
- They are cheaper compared to other valves like gate valves.
- Jacketed plug valves operate faster as they only need a quarter turn of the plug to open or close media flow.
- These valves can be used in both high-pressure and high-temperature applications.
- They are of high strength.
- Jacketed plug valves are of simple and compact design.
- These valves are easy to install and repair.
- Jacketed plug valves are free from fluid leakage.
- These valves have a low resistance to media flow which enhances flow efficiency.
- Jacketed plug valve manufacturers design these valves with few rotating parts which reduces the cost of repair due to low levels of wear.
- These valves can be either manual or automatic.
Disadvantages of jacketed plug valves
- These valves are not best for throttling flow since they reduce flow pressure by great margin.
- Jacketed plug valves need a lot of torque to open/close due to high initial force.
- Large jacketed plug valves cannot be operated manually due to the large amount of torque needed.
Troubleshooting jacketed plug valves
Valve does not open or close
- Obstruction in the valve. Open the valve according to the instructions given by the jacketed plug valve and remove obstructing materials.
- Excess line pressure. Reduce the line pressure.
- Broken stem. Replace the stem.
Leakage through the valve stem
- Worn out or damaged seal. Replace the seal.
- Loose bolts. Tighten the bolts connecting the cover and the valve body to attain the torque stated by the jacketed plug valve manufacturer.
Leakage between the body and pipe connection
- Loose connection. Tighten the connection between the body and the pipe.
- Worn out gasket. Replace the gasket.
Leakage between the plug and seat
- The seal ring is damaged or worn out. Replace the ring.
- The seat is damaged. Replace the seat.
- Excess line pressure. Ensure the valve is used at the recommended fluid pressure.
No heating fluid in the jackets
- Blockage of the jackets. Open the valve and clean off the dirt in the jackets.
Jacketed plug valves are special types of plug valve designed with heating jackets. These heating jackets contain a hot medium used to add heat to the media flowing through the valve to ensure the fluid viscosity remains low to avoid crystallization. Jacketed plug valve manufacturers design these valves to operate either manually or automatically. Jacketed plug valves operate by making a quarter turn on the valve stem. The rotation of the plug helps to align the plug port to the valve ports allowing fluid flow through the valve. To close the valve, the plug port is aligned perpendicular to the valve ports preventing fluid flow through the valve.
Jacketed plug valve manufacturers produce various types of valves such as automatic jacketed plug valves, expanding jacketed plug valves, eccentric jacketed plug valves, multiport jacketed plug valves, lubricated jacketed plug valves, and non-lubricated jacketed plug valves among others. Applications of these valves include food processing, coal tar processing, fertilizer manufacturing, and bitumen processing, and other highly viscous media among others. The advantages of using jacketed plug valves are versatile, fast operation, simple and compact design, easy installation and repair, high strength and zero leakage among others.