Cryogenic Globe Valve

What is a cryogenic globe valve?

A cryogenic globe valve is a type of globe valve which is meant for use in very cold applications. These valves are mostly used by companies that work in compressed natural gas or liquefied natural gas for throttling, opening or closing fluid flow. Cryogenic globe valve manufacturers design these valves in a way that ensures that they can transport and store the cryogenic products efficiently and safely. Some of the cryogenic globe valves are meant to work for very low temperatures such as -250 ^oC and high pressures such as 750 psi. There are also other versions of cryogenic globe valves that can work for both low temperatures and high temperatures of up to 120 ^oC. Such types of cryogenic globe valves working for both low and high temperatures are designed with a wide range of material combinations and end connections that guarantee reliable functions at such temperatures. Cryogenic globe valves manufacturers design these valves with either metallic seats or soft seats. The metallic seats are made of metallic materials such as bronze and steel. The soft seats are made of soft materials such as rubber or plastic. The choice of seat materials depends primary of temperature levels and the type of fluid to be transported through the cryogenic globe valve.

Figure: Cryogenic globe valve.

Components of a cryogenic globe valve 

Handwheel/actuator

This is the component of a cryogenic globe valve where the valve operator applies force to open or close the fluid flow. The handwheel is used for manual cryogenic globe valves. For automatic cryogenic globe valves, there is a valve actuator. The actuator is tasked with determining when to close or open fluid flow as well as providing the force needed to open or close the valve. The actuators that can be used are hydraulic, electric and or pneumatic actuators.

Valve body 

The valve body is the component of a cryogenic globe valve which is used to house internal parts of the valve. The valve body is made of a strong metallic material such as carbon steel, stainless steel, and ductile iron among others. The high-strength metallic materials ensure that the valve body is strong enough for the valve to withstand high pressures associated with fluid flow. 

Bonnet 

This is the component of a cryogenic globe valve that is used to protect the stem and stem packing. The bonnet is placed on top of the valve body and the two are connected using screws, weld or bolts to ensure no fluid leakage through the connection. The bonnet and the body are made of the same metallic material to ensure homogeneity when tightening the connection. 

Stem 

This is the component of a cryogenic globe valve that is used to connect the handwheel or actuator to the disc. The stem is also responsible for transmitting the force needed to open or close the fluid flow. Cryogenic globe valve manufacturer design the stem with threads which help to convert rotary motion into linear motion which is needed by the valve disc to open or close the valve.

Disc 

Cryogenic globe valve manufacturers use the disc for throttling, opening, and closing fluid flow. The disc gets the force to open or close fluid flow from the handwheel or actuator through the valve stem. 

Seats 

This is the part of a cryogenic globe valve where the disc fits so that it can close the fluid flow. The seat provides a uniform, replaceable and stable closing surface. 

Packing 

Packing refers to a sealing material used to cover the valve stem to prevent fluid leakage in the bonnet. The packing is made of different wearable materials such as graphite and PTFE among others. These packing materials wear out after a certain period and thus they need to be replaced to avoid fluid leakage. 

Figure: Components of a cryogenic globe valve.

How does a cryogenic globe valve work? 

A cryogenic globe valve works by using the valve disc to regulate, open, or close the fluid flow. The ability of the disc to work comes from the handwheel or actuator of the valve. The disc is connected to the handwheel so that when the handwheel is rotated the rotational motion is converted to linear motion by the valve stem threads thus making the disc move up or downwards to open or close the fluid flow. To open a cryogenic globe valve, the handwheel is rotated in the anticlockwise direction. This makes the stem rotate in the same direction as it moves upwards. As such, the disc which is connected to the stem moves up allowing space for the fluid to flow through the cryogenic globe valve. To close the valve, the handwheel is rotated in the clockwise direction making the stem rotate as it moves downwards. This makes the disc move down until it completely closes the fluid flow. Cryogenic globe valves are kept closed to help keep the media secure and safe. 

Figure: Working of a cryogenic globe valve.

Types of cryogenic globe valves 

Threaded end cryogenic globe valve 

This is the type of a cryogenic globe valve that is connected to the piping system using threads. Threaded end cryogenic globe valve manufacturers design these valves such that if the valve has male threads the piping system has female threads and vice versa. The threaded connection is used in small-sized cryogenic globe valves. These valves are quick and easy to assemble. However, cryogenic globe valve manufacturers recommend these valves for use in low-pressure and low cost applications. 

Figure: Threaded end cryogenic globe valve.

Flanged end cryogenic globe valves

This is a cryogenic globe valve that has flanges on the inlet and outlet ports. Both the valve and the pipeline have flanges with holes. The two flange sides of the cryogenic globe valve and the pipeline are connected using bolts and nuts. A gasket is also placed between the two flanges to help in enhancing a tight seal free from fluid leakage. Flanged end cryogenic globe valve manufacturers make these valves for use in high-pressure applications. Flanged end cryogenic globe valves are easy to install, assemble and disassemble. However, these valves are heavy relative to the threaded end counterparts because of the bolts and nuts used as well as the flanged ends. 

Figure: Flanged end cryogenic globe valve.

Welded end cryogenic globe valve 

This is a cryogenic globe valve that is connected to the pipeline using welding method. After the valve and the pipeline are welded together, the weld perimeter is tested using a non-destructive test method to ensure that no defect might cause fluid leakage while the valve is in use. This type of valve guarantees reliable connection free from fluid leakage even when the valve is transporting high-pressure fluids. However, welded end cryogenic globe valves cannot be disassembled in case of any malfunction. 

Figure: Welded end cryogenic globe valve.

Manual cryogenic globe valve 

This is a cryogenic globe valve that is operated manually. This is the type of a cryogenic globe valve that has a handwheel where the valve operator applies force to open, regulate or close the fluid flow. Manual cryogenic globe valves are cheaper relative to the automatic type. However, these valves tend to be of safety concern to the valve operator because in case of any leakage or malfunction the operator can be seriously injured. Also, manual cryogenic globe valves are not suitable for use where the valve needs to opened and closed frequently. Cryogenic globe valve manufacturers recommend these valves for use where the valve is not operated too often since they may make the valve operator very tired and thus perform work poorly.

Automatic cryogenic globe valves

This is a cryogenic globe valve that is operated using a valve actuator. The automatic cryogenic globe valve manufacturers design these valves with sensors that help to determine when to open, regulate or close the fluid flow. The actuator is also tasked with providing the torque required to operate the valve. The amount of torque required varies from valve to valve and it depends on the pressure level of the fluid. With an automatic cryogenic globe valve, there is no need for a valve operator. Also, this type of valve helps to reduce health hazards that might occur because of injuries to the valve operator when the valve malfunctions or in case of fluid leakage. However, automatic cryogenic globe valves are more expensive compared to their manual counterparts. 

Applications of cryogenic globe valves 

• Medical industry. 
• Transportation of liquefied natural gas in the petroleum industry. 
• Transportation of compressed gas or air. 
• Separation of air.
• Chemical industries. 
• Research and development industries. 

Advantages of cryogenic globe valves 

• Different industrial applications. 
• These valves operate faster unlike other cryogenic valves such as those with gates. 
• Can be automatic or manual. 
• Free from fluid leakage. 
• They are durable as they can be used for long periods giving value for money.
• These valves can be repaired if they get damaged or a certain component wears out. 
• Suitable for regulating fluid flow. 

Disadvantages of cryogenic globe valves 

• Very sensitive such that in case of leakage they can cause serious hazards and excessive damage. 
• Heavy relative to other valves like ball valve. 
• Not efficient enough as they have a high-pressure loss. 
• More complicated and expensive relative to other valves like gate valve. 

Troubleshooting cryogenic globe valve 

Fluid leakage through the body-pipe connections

• Worn out connection gasket. Replace the gasket. 
• Loose bolts or screw connection. Tighten the connection as per the cryogenic globe valve manufacturer’s instructions. 

Leakage through the stem packing 

• Stem packing is worn out or damaged. Replace the stem packing. 
• Loose packing nut. Tighten the packing nut as per the Cryogenic globe valve manufacturer’s instructions. 

Leakage through the valve body 

• Impact damage. Contact the cryogenic globe valve manufacturer for further details. 

The valve is hard to open or close

• Foreign materials are stuck in the valve. Disassemble the valve according to the instructions given by the cryogenic globe valve manufacturer and remove any foreign materials in the valve. 
• Stem threads are damaged. Replace the stem. 
• The stem is bent. Rectify or replace the stem. 

Summary 

A cryogenic globe valve is a type of valve that is used for very low-temperature applications. Such low temperatures could be as low as -250 ^oC. Cryogenic globe valve manufacturers design these valves for use in throttling, opening, and closing fluid flow. It uses strong metallic materials such as carbon steel, stainless steel, ductile iron, and bronze among others. These materials are used to make the valve body, bonnet, stem, and disc. This helps the valve to remain strong so that it can withstand the high pressure associated with the fluid.

There are various types of cryogenic globe valves which include threaded end cryogenic globe valves, flanged end cryogenic globe valves, welded end cryogenic globe valves, automatic cryogenic globe valves, and manual cryogenic globe valves. Cryogenic globe valves are used in various applications such as medical industry, research and development, liquefied natural gas, compressed gas, chemicals, and air separation among others. Advantages of using cryogenic globe valves are zero leakage, good throttling capabilities, fast operation, automatic or manual operation, durability, and they are versatile. However, cryogenic globe valves are used to control flow of sensitive fluids which in case of any leakage they can cause serious hazards and excess damage. Also, these valves employ a complicated design which makes them not only heavy but also have high-pressure drops.