Types of Valves in Cryogenic Application

For applications involving high pressure, cryogenic valves are indispensable. They offer efficient sealing that abides by stringent testing standards, ensuring that businesses can rely on them without encountering any issues. Manufacturers meticulously design and test these valves, taking into account all necessary safety measures.

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To fulfill your specific needs, opting for the best cryogenic valves from reliable vendors is vital. Dombor, a leading producer of cryogenic valves for over two decades, serves various industries. Reach out to Dombor to discuss your requirements and find the perfect cryogenic solution. Balancing quality and affordability is critical, and Dombor can help your business achieve this equilibrium.

Understanding Cryogenic Valves

Cryogenic valves are specialized components designed to operate efficiently under extreme temperature conditions. These valves are constructed from materials that can withstand temperatures below -101°C, commonly associated with cryogenic substances and fluids.

The operational temperature range for cryogenic valves spans from 37°F to -320°F. Each valve is designed to handle different temperature extremes. Often, these valves feature extended stems to prevent the valve stem seal from touching the cold fluid. This design enhances the valve's ability to provide a bubble-tight cutoff, crucial for preventing leaks of potentially hazardous chemicals.

The Working Mechanism of Cryogenic Valves

Cryogenic valves typically remain closed to securely contain cryogenic gases or other media. They respond to high pressure by opening, allowing the medium to pass through. This open state persists until the pressure drops, at which point the valve closes, providing a bubble-tight seal to prevent any leakage.

External pressure plays a role in the operation of cryogenic valves. Generally kept in a closed state, these valves are designed to respond to increases in pressure by opening, facilitating the flow of the medium. This flow continues until the pressure decreases.

Diverse Designs of Cryogenic Valves

Multiple types of valves are available for various applications, each with its own set of benefits, making it crucial to select the appropriate type for specific needs.

• Pressure Relief Valve: These safety components are used in pneumatic systems to regulate air pressure levels, preventing them from exceeding limits that could damage equipment or endanger personnel. Essential in the LNG sector for overpressure protection, these valves must possess enhanced sealing properties to function effectively at cryogenic temperatures.

• Cryogenic Ball Valve:

Industrial ball valves control the flow of liquids, gases, and vapors by rotating a ball within the valve. These valves feature extended stems and bonnets to keep the cryogenic fluid channel above the stem packing, forming an insulating column that protects against damage from localized freezing.

• Cryogenic Gate Valve: These valves either fully permit or block media flow. With a full port design, they minimize fluid pressure losses and facilitate maintenance operations within pipes. Frequently used in gas liquefaction systems, these valves have an expanded bonnet to excel at extremely low temperatures.

• Cryogenic Butterfly Valve: Known for having a round disc at their core, these valves are shorter and provide quick operation. They are easier to handle, lighter, and more cost-effective, although their sensitivity requires careful handling to prevent seal cracks due to temperature fluctuations.

• Cryogenic Globe Valve: Utilizing a disc closure, these valves can start, stop, or regulate flow, making them ideal for throttling tasks. Best used in small pipework, they offer long-term performance and durability.

Materials Used in Cryogenic Valve Manufacturing

Cryogenic valves are typically constructed from materials like aluminum, stainless steel, brass, Incoloy, bronze, and zirconium, with seals made from graphite or PTFE. The choice of material depends on the temperature range the valve must endure. Inappropriate material choices can lead to severe issues, including cracking and leaks.

Key Components of Cryogenic Valves

The primary components of a cryogenic valve include:

• Body: Houses the moving parts and withstands system pressure. Made from cast or forged steel, following standards such as ASTM A352 LCB/LCB and ASTM A350 LF2/LF3.
• Bonnet: Protects the stuffing box from low temperatures and prevents cold energy loss.
• Actuator: Attached to the disc and stem, it opens and closes the valve.
• Disc: Controls the flow by its position. It can be cast, forged, or fabricated.
• Seat: Critical for leak prevention, made from metal or non-metallic forged rings. Can have single or multiple seats.
• Stem: Ensures efficient operation by keeping the packing above 8°C.
• Valve Trim: Comprises the internal components that contact the medium, made from various materials to handle different conditions.

Standards Governing Cryogenic Valves

Standards such as ASME 16.34, BS, and ISO guide the design, production, and testing of cryogenic valves:

• ASME 16.34: Defines critical criteria for valve components, including closure tests and material selection.
• BS: Outlines design, manufacturing, and testing requirements, including electrical continuity and procedures for valve production and testing.
• ISO: Internationally, this standard sets the requirements for valves used in cryogenic fluid operations, covering both cryogenic and ambient temperature operations.

Applicable Industries for Cryogenic Valves

Cryogenic valves are essential in various industrial settings that utilize low-temperature processes. Some key industries include:

• Oil and Gas: Handling liquified gases like methane and nitrogen for safe storage and transportation, playing a role in power generation.
• Chemical and Petrochemical: Ideal for processing low-temperature substances like liquid oxygen and ethylene.
• Air Separation: Used in separating gases from air through pressure techniques.
• Food and Beverage: Used in processing plants to move products into and out of freezers.
• Healthcare: Found in medical facilities for storing equipment and transferring gases like oxygen.

Why Cryogenic Valves are Crucial in These Applications

Cryogenic valves are vital in handling, storing, and transporting cryogens and high-pressure fluids under extremely low temperatures. These specialized valves must withstand high pressures and extreme temperatures.

They are commonly used in sectors like LNG, petrochemicals, and food processing due to their effectiveness in transporting low-temperature fluids. Proper material selection ensures that these valves can endure chemicals and fluctuating temperatures and pressures.

Given the costs and risks associated with cryogen leakage, it is crucial to insulate valves and piping to mitigate environmental heat gains. The unique properties of cryogenic gases make it essential to use valves that prevent unintended leakage at severe temperatures.

Guidelines for Selecting the Right Cryogenic Valve

Choosing valves for cryogenic applications can be challenging. It involves considering the conditions at factories or on ships, as well as ensuring the valve's performance matches the unique properties of cryogenic fluids. Proper selection ensures equipment protection, operational safety, and plant reliability.

• Material Selection: The valve body must withstand temperature fluctuations without deforming. Stainless steel and aluminum alloys are commonly used based on temperature requirements.
• Safety: Ensure the valve is vented to account for the extreme expansions of liquids.
• Valve Types: Ball valves, butterfly valves, and gate valves are commonly used for their reliability and performance. Selection often depends on specific customer requirements.
• Temperature: Consider valves designed for ultra-low temperatures, especially in sectors like air separation and petrochemicals.
• Maintenance: Ensure valves are assembled in clean chambers and are free from lubricants or contaminants. Proper cleaning and assembly practices are crucial for optimal performance.

Conclusion: The Importance of Choosing Quality Cryogenic Valves

Ensuring the safe and efficient handling of cryogenic liquids requires high-quality cryogenic valves. For businesses interested in enhancing their processes with reliable cryogenic solutions, Dombor offers the expertise and products that balance quality and affordability. For comprehensive support on your cryogenic valve needs, reach out to professionals who can guide you through every step, ensuring smooth operational integration.