Technology

The advanced production technology employed at our manufacturing plants allows us to supply more than just high quality gas mixtures in non-refillable canisters. Our customers need to know with certainty that our products are legislatively compliant, and deliver accuracy, stability, and reliability for a range of critical applications. To deliver these objectives Air Products utilize a number of technologies and advanced production methods, and draw on over 40 years of research and development experience in the field of gas mixture production.

Canister Design

The canisters used are very carefully chosen to suit the gases they will contain. The materials used, surface finish, internal preparation and special internal coatings, combine to ensure that our non-refillable cylinders support accurately certified and stable gas mixtures. These steps are vital, because even trace amounts of moisture or other impurities absorbed from the canister surface can seriously alter the composition of many gas mixtures. For non-refillables this is especially important as the ratio of internal surface area to gas content is very high.

Metallurgy is one of many key factors that affect mixture reliability in non-refillables. Air Products has exhaustively researched into the optimum materials for ensuring the long term stability of such gas mixtures in canisters, even those incorporating highly reactive components like hydrogen sulphide. Some metal alloys adversely affect mixture stability and reliability. Air Products technology leaders understand the science of metallurgy and its effect on gas mixture composition. We are confident our cylinder coating technology and methods are the best in the world.

All Air Products canisters comply fully with all appropriate European legislation. Our larger 34L, 58L, and 110L canisters comply with EN 12205, ISO11118 and are marked accordingly with the π mark.

Our smallest non-refillable canister is classed as an aerosol. 10L aerosol canisters supplied by Air Products are compliant with 75/324/EEC as referenced in ADR 2011, section 6.2.6.4.

Valve Design

The stainless steel ‘C10’ valves used on our 34L, 58L, and 110L canisters are of a patented design which physically prevents the canisters from being refilled. A method of physically preventing the refill of canisters is an important part of legislative compliance. It is a requirement of EN 12205 that non-refillable canisters feature a non-refillable valve in accordance with EN 13340. The π mark on the canisters shows that they meet the provisions of the transportable pressure equipment directive (TPED).

Production Technology

Generally, calibration gas mixtures in non-refillables are manufactured gravimetrically in refillable cylinders, which involves the addition of gases by mass using highly accurate weigh scales that are traceable to international standards. We then use dedicated high integrity filling panels to decant these mixtures into the lightweight non-refillable canisters. All aspects of gas mixture production are coordinated at our fully integrated Speciality Gases manufacturing plant in the UK, and it means we have absolute control of mixture production from start to finish.

Each and every mixture type incorporating a reactive gas An example of a reactive component is hydrogen sulphide used extensively in industrial hygiene for validating gas detection equipment. component undergoes analytical verification by statistical batch analysis. We do this many times between the initial fill and the dispatch date, because mixture stability and reliability is of paramount importance to our customers.

The range of mixtures and component types offered in non-refillables is varied. Many require specific treatment methods and we use our
state-of-the-art filling equipment to allow us to achieve these. This includes industrial ovens designed to recreate and accelerate extreme usage conditions. Subsequently we verify the stability of our canisters analytically over time. Only then can we prove that the mixtures are stable and can be released to our customers.