As its name suggests, cryogenic valves are designed to be used in very cold applications. They are thus most popularly used by companies that work with Liquefied Natural Gas (LNG) or Compressed Natural Gas (CNG). For instance, the oil and gas industry frequently uses cryogenic temperature ranges starting at -150°C (-238°F). Additionally, some gasses aren't labeled 'cryogenic' because of their temperature, but rather because they require more than a simple pressure increase to compress their volume. Cryogenic valves are built to help transport and store such cryogenic gasses safely and efficiently.
If you are looking for more details, kindly visit our website.
Cryogenic valves are constructed to store such gases safely and also work great during transportation due to their ability to function efficiently in pressure settings as high as 52 bar (750 psi) and temperature as low as -196°C (-320°F).
Working Cryogenic Valves
Cryogenic valves are kept in a natural closed position to keep cryogenic gasses or other medium secure and safely contained. A cryogenic valve is generally designed to react to high pressure which pushes the valve into the open position to allow the gas or other media to flow readily through. Such open flow will continue until the pressure again decreases, at which point it will swing back nd become seal with a special metal seat bubble-tight shutoff to prevent any leaking.
Testing Cryogenic Checkvalve
Why are other valves not suitable?
Cryogenic gases and other media are extremely sensitive. Having it leak in an unwanted place can cause serious and very expensive damages, especially as it is a costly endeavor to transform standard temp gasses into cryogen.
Standard valves are sensitive to the extreme temperatures as they contract and expand at various rates when exposed to hot and freezing conditions, thus causing breaks in the seal and enabling the undesired leakage. It's these heat gains that have long been a problem in the study, transport, and storage of cryogenic gas processing.
Why cryogenic valve has a extended bonnet?
Ethylene, liquid oxygen, liquid hydrogen, liquefied natural gas, liquefied petroleum, and other liquid media the cryogenic valve transfers are flammable and explosive. What is more, they are going to gasify and expand hundreds of times when the temperature rises.
This kind of valve is always equipped with an extended bonnet or namely extended stem. That’s because:
above 8℃.
Hence，the valve body and the pipeline are welded together to reduce the leakage of the cold box as much as possible and ensure the sealing performance of the valve.
Types and differences of Cryogenic valves
Today, we can find various shapes and sizes of cryogenic valves, suitable for working at various pressure ranges. Some of the most common are Ball, Butterfly, Gate, Globe, Check and Relief valves. In addition, they can be manual or automatic, which is indispensable in large systems.
Cryogenic ball valves also include a polytetrafluoroethylene body. Their flow rate is therefore better than that of globe valves. They are also very efficient when a tight seal is required in systems. However, it should be noted that they can easily wear around the seals and the ball itself. Therefore, their application is recommended in systems with unrestricted flow paths.
Cryogenic butterfly valves have a circular disc in the centre, which gives them a shorter length. They are lightweight, economical, simple to operate, and are used in systems that need fast opening and closing actions.
Cryogenic gate valves have a wedge-shaped gate that closes in line with the body mounting. This results in minimal pressure drop, even in its fully open position.
Cryogenic globe valves have a spherical shape and an internal moving disc that rotates at a 90-degree angle to the plane of its body mounting. In this way, they provide effective long-term sealing. However, they are not recommended for use in high flow systems.
Cryogenic relief valves protect against overpressure above a certain value and allow steam to escape if the safety limits are exceeded. In a similar vein, cryogenic check valves maintain pressure and prevent fluids from flowing back.
Remark(s) of the Author...
Cavity relief Ball valve
Years ago, when I was working for Shell, I first heard about a Cavity relief ball valve in cryogenic service. Well what could it be?.
For more information, please visit Xiangyu.
SHELL MESC stipulates a pressure equalizing hole of at least 3 mm in the ball. It states that the ball valve must have an automatic way to relieve overpressure. Cryogenic standard BS 6364 tells us the same.
The use of self-venting ball seats according to EEMUA 182 specifications is another solution. The surplus pressure spews out around the ball seat.
We must always keep in mind that cryogenic gases are very sensitive and leakage can pose a serious risk. In this sense, a cryogenic valve is a guarantee for the proper functioning of the system.
Reference(s) for this page:
www.dvsvalve.com
www.evergreenmidwest.com
valveman.com
www.cam-spa.it
Cryogenic valves can withstand and operate effectively at extremely cold temperatures. They serve in a variety of fields including the petrochemical and aerospace industry, where there is a need to handle fluids at such temperature levels. Although the definition of cryogenic temperature varies according to industry, it is common to see cryogenic valves operate between -40℉ (-40℃) to values below -320℉ (-196℃). In this article, we will review the common uses of cryogenic valves, types, standards, and testing.
Cryogenic valves are mostly found in industrial facilities to harness the benefits of undergoing processes at cryogenic temperatures. Thus, the following sections highlight some of these applications.
In the oil and gas industry, cryogenic valves serve in the control of liquified gasses such as liquid nitrogen, methane, and helium. Because of the ease and safety of non-pressurized storage and transport, these elements cool to cryogenic temperatures, so they remain in the liquid state. As a result, larger volumes can be transported or stored for some time, while the piping system operates at much lower pressure levels. Before cooling these gasses into liquid, it is necessary to remove condensate, moisture, CO2, and H2S to prevent corrosion problems downstream.
From World War II, the field of cryogenics enjoyed accelerated development with its eventual commercialization in 1966 by Ed Busch. Busch increased metal tool design life by up to two to four times via cryogenic tempering rather than heat treatment. As a result, it is common to find cryogenic valves and accompanying equipment in steel production plants today. Another area of use is in the freezing of foods and biotech products such as vaccines.
In the aerospace industry, cryogenic fuels have gained wide acceptance over the years. Liquid hydrogen and liquid oxygen often serve as propellants for space shuttles, either alone or in combination with jet fuel. The presence of cryogenic valves is a must in such systems.
As previous sections highlight, there are a variety of cryogenic applications. Similarly, there are a variety of valve types that can serve in these applications, with each having its own benefits. Thus, it is necessary to select the right type that suits an application. Generally, a basic feature of all cryogenic valves is having a tight shut-off. Cryogenic fluids are sensitive, and any leakage can cause harmful and expensive damage.
The triple-offset butterfly valve is an ideal option for cryogenic service. This is due to its non-friction, metal-to-metal seal that provides bubble-tight shut-off and the long-term integrity of the sealing mechanism. Additionally, they offer quick opening and closing action and are the ideal choice for remote operation. The Durco TX3 butterfly valve provides such an example – with excellent shutoff capabilities, low torque, and reduced wear benefit.
These valves have a spherical shape with a disc that rotates 90° to the plane of its body seat. Therefore, it provides effectiveness for long-term sealing. However, they may not resist erosion for long and are not recommended for systems with high flow rates. Ideally, globes should be provided with a full Stellite valve trim to protect against erosion. Cryogenic fluids tend to lose their lubricity, and the Stellite helps to reduce the wear and tear on the valve.
The most common valves for liquid gas applications are the double-seal ball valves such as the L&T and AMPO Poyam. Generally, they offer better flow characteristics than globe valves. Also, they are very efficient in providing a tight seal. They also incorporate a vapor space of sufficient height that allows gasification in the area below the gland. Consequently, this keeps the gland packing near the ambient temperature as thermal conductivity between the inside and outside of the valve is limited. Yet, due to wear concerns along the seals and the ball, they find preference in applications with an unrestricted flow path.
A typical cryogenic gate valve has a wedge-shaped gate, which opens and closes in line with the mating body seat. As a result, there is minimal pressure drop when in a fully open position. Thus, it provides desirable flow characteristics. For larger valve sizes, gate valves such as the Poyam, L&T, and the smaller forged NEWCO are preferred in place of ball valves, which can be more costly. However, gates are more difficult and expensive to actuate in comparison to butterfly valves, especially as their size increases, so they are not ideal for remote operation. Gates can be prone to wear and tear if they are subject to often repeated opening and closings. An advantage gate valves have is that due to the metal-to-metal sealing surfaces, they are not subject to the cold flow that Teflon seals in ball valves tend to see.
Ideally, gate valves should be provided with a Full Stellite Trim (Stellite on both the seat and the disc) to protect against erosion. Cryogenic fluids tend to lose their lubricity and the Stellite helps to reduce the wear and tear on the valve.
Although some companies have specific requirements for cryogenic valve service, most of these requirements stem from engineering standards such as MSS SP-134, BS 6364, ASME 16.34, and ISO 21011.
The MSS SP-134 is the dominant code in use within North America. It covers requirements for material, design, dimensions, fabrication, pressure testing, and non-destructive examination of cryogenic valves with body/bonnet extensions. Below is a summary of the recommendations of this design code:
This British Standard specifies requirements for the design, manufacture, and testing of valves for cryogenic service. A summary of its requirements is as follows:
The ASME 16.34 contains important specifications covering parts relating to the valve such as flange, threading, and welding end. A few of the details include:
This international standard outlines requirements for the design, manufacture, and testing of valves for the operation of cryogenic fluids. In addition, the specifications cover operation at temperatures from ambient to cryogenic. A summary of its recommendations is as follows:
There are a host of other standards that are useful when dealing with cryogenic valves. Some of these standards and areas of coverage include:
Like every other type of valve, cryogenic valves are subjected to valve testing, according to the type of valve in use. Nevertheless, some of the tests which are always a requirement include:
As its name suggests, cryogenic valves are designed to be used in very cold applications. They are thus most popularly used by companies that work with Liquefied Natural Gas (LNG) or Compressed Natural Gas (CNG). For instance, the oil and gas industry frequently uses cryogenic temperature ranges starting at -150°C (-238°F). Additionally, some gasses aren't labeled 'cryogenic' because of their temperature, but rather because they require more than a simple pressure increase to compress their volume. Cryogenic valves are built to help transport and store such cryogenic gasses safely and efficiently.
Cryogenic valves are constructed to store such gases safely and also work great during transportation due to their ability to function efficiently in pressure settings as high as 52 bar (750 psi) and temperature as low as -196°C (-320°F).
Working Cryogenic Valves
Cryogenic valves are kept in a natural closed position to keep cryogenic gasses or other medium secure and safely contained. A cryogenic valve is generally designed to react to high pressure which pushes the valve into the open position to allow the gas or other media to flow readily through. Such open flow will continue until the pressure again decreases, at which point it will swing back nd become seal with a special metal seat bubble-tight shutoff to prevent any leaking.
Testing Cryogenic Checkvalve
Why are other valves not suitable?
Cryogenic gases and other media are extremely sensitive. Having it leak in an unwanted place can cause serious and very expensive damages, especially as it is a costly endeavor to transform standard temp gasses into cryogen.
Standard valves are sensitive to the extreme temperatures as they contract and expand at various rates when exposed to hot and freezing conditions, thus causing breaks in the seal and enabling the undesired leakage. It's these heat gains that have long been a problem in the study, transport, and storage of cryogenic gas processing.
Why cryogenic valve has a extended bonnet?
Ethylene, liquid oxygen, liquid hydrogen, liquefied natural gas, liquefied petroleum, and other liquid media the cryogenic valve transfers are flammable and explosive. What is more, they are going to gasify and expand hundreds of times when the temperature rises.
This kind of valve is always equipped with an extended bonnet or namely extended stem. That’s because:
above 8℃.
Hence，the valve body and the pipeline are welded together to reduce the leakage of the cold box as much as possible and ensure the sealing performance of the valve.
Types and differences of Cryogenic valves
Today, we can find various shapes and sizes of cryogenic valves, suitable for working at various pressure ranges. Some of the most common are Ball, Butterfly, Gate, Globe, Check and Relief valves. In addition, they can be manual or automatic, which is indispensable in large systems.
Cryogenic ball valves also include a polytetrafluoroethylene body. Their flow rate is therefore better than that of globe valves. They are also very efficient when a tight seal is required in systems. However, it should be noted that they can easily wear around the seals and the ball itself. Therefore, their application is recommended in systems with unrestricted flow paths.
Cryogenic butterfly valves have a circular disc in the centre, which gives them a shorter length. They are lightweight, economical, simple to operate, and are used in systems that need fast opening and closing actions.
Cryogenic gate valves have a wedge-shaped gate that closes in line with the body mounting. This results in minimal pressure drop, even in its fully open position.
Cryogenic globe valves have a spherical shape and an internal moving disc that rotates at a 90-degree angle to the plane of its body mounting. In this way, they provide effective long-term sealing. However, they are not recommended for use in high flow systems.
Cryogenic relief valves protect against overpressure above a certain value and allow steam to escape if the safety limits are exceeded. In a similar vein, cryogenic check valves maintain pressure and prevent fluids from flowing back.
Remark(s) of the Author...
Cavity relief Ball valve
Years ago, when I was working for Shell, I first heard about a Cavity relief ball valve in cryogenic service. Well what could it be?.
SHELL MESC stipulates a pressure equalizing hole of at least 3 mm in the ball. It states that the ball valve must have an automatic way to relieve overpressure. Cryogenic standard BS 6364 tells us the same.
The use of self-venting ball seats according to EEMUA 182 specifications is another solution. The surplus pressure spews out around the ball seat.
We must always keep in mind that cryogenic gases are very sensitive and leakage can pose a serious risk. In this sense, a cryogenic valve is a guarantee for the proper functioning of the system.
Reference(s) for this page:
www.dvsvalve.com
www.evergreenmidwest.com
valveman.com
www.cam-spa.it
Cryogenic valves can withstand and operate effectively at extremely cold temperatures. They serve in a variety of fields including the petrochemical and aerospace industry, where there is a need to handle fluids at such temperature levels. Although the definition of cryogenic temperature varies according to industry, it is common to see cryogenic valves operate between -40℉ (-40℃) to values below -320℉ (-196℃). In this article, we will review the common uses of cryogenic valves, types, standards, and testing.
Cryogenic valves are mostly found in industrial facilities to harness the benefits of undergoing processes at cryogenic temperatures. Thus, the following sections highlight some of these applications.
In the oil and gas industry, cryogenic valves serve in the control of liquified gasses such as liquid nitrogen, methane, and helium. Because of the ease and safety of non-pressurized storage and transport, these elements cool to cryogenic temperatures, so they remain in the liquid state. As a result, larger volumes can be transported or stored for some time, while the piping system operates at much lower pressure levels. Before cooling these gasses into liquid, it is necessary to remove condensate, moisture, CO2, and H2S to prevent corrosion problems downstream.
From World War II, the field of cryogenics enjoyed accelerated development with its eventual commercialization in 1966 by Ed Busch. Busch increased metal tool design life by up to two to four times via cryogenic tempering rather than heat treatment. As a result, it is common to find cryogenic valves and accompanying equipment in steel production plants today. Another area of use is in the freezing of foods and biotech products such as vaccines.
In the aerospace industry, cryogenic fuels have gained wide acceptance over the years. Liquid hydrogen and liquid oxygen often serve as propellants for space shuttles, either alone or in combination with jet fuel. The presence of cryogenic valves is a must in such systems.
As previous sections highlight, there are a variety of cryogenic applications. Similarly, there are a variety of valve types that can serve in these applications, with each having its own benefits. Thus, it is necessary to select the right type that suits an application. Generally, a basic feature of all cryogenic valves is having a tight shut-off. Cryogenic fluids are sensitive, and any leakage can cause harmful and expensive damage.
The triple-offset butterfly valve is an ideal option for cryogenic service. This is due to its non-friction, metal-to-metal seal that provides bubble-tight shut-off and the long-term integrity of the sealing mechanism. Additionally, they offer quick opening and closing action and are the ideal choice for remote operation. The Durco TX3 butterfly valve provides such an example – with excellent shutoff capabilities, low torque, and reduced wear benefit.
These valves have a spherical shape with a disc that rotates 90° to the plane of its body seat. Therefore, it provides effectiveness for long-term sealing. However, they may not resist erosion for long and are not recommended for systems with high flow rates. Ideally, globes should be provided with a full Stellite valve trim to protect against erosion. Cryogenic fluids tend to lose their lubricity, and the Stellite helps to reduce the wear and tear on the valve.
The most common valves for liquid gas applications are the double-seal ball valves such as the L&T and AMPO Poyam. Generally, they offer better flow characteristics than globe valves. Also, they are very efficient in providing a tight seal. They also incorporate a vapor space of sufficient height that allows gasification in the area below the gland. Consequently, this keeps the gland packing near the ambient temperature as thermal conductivity between the inside and outside of the valve is limited. Yet, due to wear concerns along the seals and the ball, they find preference in applications with an unrestricted flow path.
A typical cryogenic gate valve has a wedge-shaped gate, which opens and closes in line with the mating body seat. As a result, there is minimal pressure drop when in a fully open position. Thus, it provides desirable flow characteristics. For larger valve sizes, gate valves such as the Poyam, L&T, and the smaller forged NEWCO are preferred in place of ball valves, which can be more costly. However, gates are more difficult and expensive to actuate in comparison to butterfly valves, especially as their size increases, so they are not ideal for remote operation. Gates can be prone to wear and tear if they are subject to often repeated opening and closings. An advantage gate valves have is that due to the metal-to-metal sealing surfaces, they are not subject to the cold flow that Teflon seals in ball valves tend to see.
Ideally, gate valves should be provided with a Full Stellite Trim (Stellite on both the seat and the disc) to protect against erosion. Cryogenic fluids tend to lose their lubricity and the Stellite helps to reduce the wear and tear on the valve.
Although some companies have specific requirements for cryogenic valve service, most of these requirements stem from engineering standards such as MSS SP-134, BS 6364, ASME 16.34, and ISO 21011.
The MSS SP-134 is the dominant code in use within North America. It covers requirements for material, design, dimensions, fabrication, pressure testing, and non-destructive examination of cryogenic valves with body/bonnet extensions. Below is a summary of the recommendations of this design code:
This British Standard specifies requirements for the design, manufacture, and testing of valves for cryogenic service. A summary of its requirements is as follows:
The ASME 16.34 contains important specifications covering parts relating to the valve such as flange, threading, and welding end. A few of the details include:
This international standard outlines requirements for the design, manufacture, and testing of valves for the operation of cryogenic fluids. In addition, the specifications cover operation at temperatures from ambient to cryogenic. A summary of its recommendations is as follows:
There are a host of other standards that are useful when dealing with cryogenic valves. Some of these standards and areas of coverage include:
Like every other type of valve, cryogenic valves are subjected to valve testing, according to the type of valve in use. Nevertheless, some of the tests which are always a requirement include: