How to Specify a Cryogenic Valve

cryogenic valve options

Cryogenic valves control the flow of liquid super-cooled gases like nitrogen, hydrogen, argon, oxygen, or helium. The gases must be kept extremely cold to stay liquid, so cryogenic control valves are designed to function while minimizing warming.

Cryogenic valve specifications depend on the cryogen, the system or equipment the valve will be part of, the way the valve will open and close, the pressure and flow rate of the liquid, and any safety or convenience features required.

Is this valve for a liquid helium system?

Because liquid helium boils off (becomes a gas again) at an extremely low temperature, the ideal valve has a stem and support tube designed for low heat conduction resulting in the lowest possible rate of heat leak. Cryocomp’s C3000 valve series is specially designed for liquid helium systems.

Is this valve for a liquid nitrogen, argon, or oxygen system?

A liquid nitrogen flow control valve design can also be used for argon or oxygen. If the valve is to be used for oxygen service, special cleaning is required. Cryocomp’s C2000 and C5000 series valves are ideal for these cryogens.

Does the liquid need to flow straight through the valve?

If so, select either a globe or y-pattern valve. A globe-style valve is a common design, the valve stem is perpendicular to the flow of liquid. A y-pattern valve can be installed in a tighter space since the valve stem is at an angle to the flow.
If the liquid flow must change direction, use a right angle style valve. Here is a list of Cryocomp valves by body style.

What size is the piping?

Valves are sized to match industry-standard piping or tubing. Cryocomp makes valves to fit ½” tube to 2” piping systems.

How will the valve connect with the cryogenic system?

The most common types of connections are pipe or tube weld ends. We can manufacture cryogenic valves with other connections, like MPT or FPT threads, a flare tube and nut, socket weld pipe or tube, or socket weld copper.

Will the valve require actuated operation?

Actuated valves stop or start the flow of liquid, pneumatically actuated valves are powered by compressed air, and solenoid valves are powered with electricity. Actuated valves can be automated.
Manual valves turn the liquid flow on or off with a simple handle turn.

What kind of insulation is needed?

We make cryogenic valves with or without full vacuum jackets. The vacuum space keeps cryogenic liquids from picking up heat from the environment. For cold box applications, we provide a partial vacuum jacket sometimes called a cold box cuff.

Will the valve need a purge port and/or a relief valve?

A purge port allows access to the vacuum space, a relief valve is a safety feature that will open at a pre-determined pressure.

Will your valve require a precision flow rate?

Standard ½” size C2000 and C3000 valves have a flow coefficient of 2.6 for globe style body designs, and 5.7 for right-angle style body designs. Cryocomp can build a valve to your exact liquid flow requirements, with a tolerance of Cv=.500 down to .0003.
Here is the CV Calculation formula and a specific gravity table for cryogenic liquids to use in calculating the flow coefficient.

Does your application require more than a single valve?

Any number of manual or actuated valves can be incorporated into a single manifold. A custom-designed manifold can have bayonet connections, tee or elbow joints, flexible hose, expansion joints, or instrumentation.

We are specialists in cryogenic valves and would be happy to discuss your specific application. Contact us today, at sales@cryocomp.com, or simply fill out the quote request form.