Cryogenic Safety Products

Products & Services

Why is safety so important in the dispensing of cryogens?

Dewar Safety Switch

We are proud to introduce the Gas and Liquid Controls Dewar Safety Switch, an essential addition for safety-conscious users of liquid nitrogen Dewars; particularly those in lone working environments.
When the foot switch is depressed, the safety valve opens, to allow normal use of the Dewar valve/tap.  If the operator finds that the Dewar valve freezes, sticks open or finds themselves in difficulty and in need of a quick shut-off, they can simply lift off the foot switch and flow will stop immediately.
The unit comprises of a stainless-steel battery compartment, with a carry handle and hooks to hang from a Dewar, along with a foot-operated floor switch and solenoid valve (specially rated for cryogenic use).
Cryogens have become indispensable in various fields, from scientific research to medical applications and industrial processes. Cryogens such as liquid nitrogen, liquid helium, and argon are stored and dispensed from specialised containers known as Dewars. While these cryogens offer numerous advantages, their handling demands strict safety protocols to protect both personnel and equipment. In this article, we will explore the safe dispensing of cryogens from Dewars, highlighting the essential guidelines and best practices to ensure a secure working environment.
Cryogens are substances that exist at temperatures below -150°C (-238°F) and are stored in a liquid state. The most commonly used cryogens include liquid nitrogen (LN2), liquid helium (LHe), and liquid argon (LAr). These substances are vital in various applications, such as cryopreservation, cryogenic research, and cooling superconducting magnets in medical devices and particle accelerators.
Dewars are specialised containers designed to store and transport cryogens safely. They are typically double-walled and vacuum-insulated to minimise heat transfer and maintain cryogenic temperatures. Dewars come in various sizes, from small, portable containers to large, stationary tanks, depending on the specific application.

Safe Dispensing Practices

Proper Training – One of the most critical aspects of safe cryogen dispensing is ensuring that personnel are well-trained. All individuals handling cryogens should receive comprehensive training on the specific cryogen being used and the equipment involved. Training should cover safety procedures, emergency response protocols, and the properties of cryogens.
Personal Protective Equipment (PPE) – Appropriate PPE is essential when working with cryogens. At a minimum, this includes gloves, safety goggles or a full-face shield, and insulated, closed-toe shoes. Additional protective clothing may be required for specific applications, such as cryogenic aprons, face masks, and cryogenic gloves.
Proper Ventilation – Cryogens release gas as they evaporate, which can displace oxygen and create an asphyxiation hazard in enclosed spaces. Ensure that work areas are well-ventilated to disperse cryogenic gases. Gas detectors can also be employed to monitor oxygen levels.
Equipment Inspection – Regularly inspect Dewars and associated equipment for signs of wear, damage, or leaks. Dewars should be kept in good condition to prevent potential accidents. Leaking cryogens can pose cryogenic burn hazards and reduce efficiency.
Cryogen Handling – When handling cryogens, it’s essential to use dedicated cryogenic gloves to protect against frostbite. Never allow cryogens to come into direct contact with your skin. Always use appropriate tools and equipment to minimize direct contact with cryogenic liquids.
Dispensing Techniques – Utilize proper techniques for dispensing cryogens. This is where the Gas and Liquid Controls foot dispenser is invaluable as sudden releases can lead to rapid gas expansion and potential accidents.
Dewar Labelling – Clearly label Dewars with the type of cryogen they contain and any associated hazards. This helps personnel identify the contents quickly and take appropriate precautions.
Emergency Procedures – Have well-defined emergency procedures in place. Personnel should know how to respond to cryogenic spills, fires, and injuries. Access to emergency eyewash stations, safety showers, and first aid supplies should be readily available.
Storage and Transportation – Store Dewars in well-ventilated, secure locations away from potential sources of ignition. When transporting Dewars, secure them properly to prevent tipping or damage. Use specially designed cryogenic transportation containers when necessary.

Personal Protective Equipment (PPE)

At Gas and Liquid Controls, we can provide all aspects of PPE, including safety gloves, face shields, aprons and personal oxygen depletion monitors.  Please contact us to discuss your requirements.