DIVE LOG DECEMBER 25 ISSUE 415

When Scuba Gear was Australian-Made by Des Williams

THE HUMBLE O-RING STORY To seal, or not to seal, that is the question?

Recently, I got to thinking about the development of the humble O-ring seal, which is such a vital component within the range of diving equipment of today, including demand valves, cameras, and torches. Today most seals used in diving are quality O-rings, which did not begin to make their mark in diving until the early 1950s. Before then, it was a choice between rubber or leather for making an underwater seal. When the standard dress diving helmet was introduced in the 1830s, FLAT profile, leather seals soaked in Neatsfoot oil were used and they remained in use for over 100 years. An Internet search of the history of the humble O-ring reveals that it was not until 1936 that the O-ring was invented by Danish-American Niels Christensen. Commonly associated with wartime innovation, production of the O-ring was ramped up during World War II, when demand for reliable sealing mechanisms surged, and the U.S. government acquired Christensen’s patent to support the war effort.

unusually cold temperatures before launch. Since then, material science, quality tracking, and rigorous testing have transformed how O-rings are produced and used. Today, O-rings support everything from oil fields and hydraulic systems to dental implants, beverage dispensers and diving apparatus. O-rings today are made from a large range of high-performance synthetic materials to handle extreme temperatures, corrosive chemicals, and complex

Siebe Gorman & Robison Helmets

mechanical requirements. They include: Aflas, Neoprene/Chloroprene, Ethylene Propylene, Fluoroelastomer, Fluorosilicone, Nitrile, PTFE, Silicone and Urethane/Polyurethane. But, I digress, so let’s get back to O-ring development in diving. In the early recreational diving years of the 1950s, leather seals were initially used between the demand valve (regulator) and the cylinder pillar valve. This was

The design was elegantly simple - an elastomeric loop with a circular cross-section, compressed between components to create a durable seal. Despite manufacturing processes having become increasingly sophisticated today, the simplicity of the design has stood the test of time. The importance of O-rings became tragically clear in 1986 with the space shuttle Challenger disaster, caused in part by a failed Dupont Viton O-ring that lost flexibility in

18

DIVE LOG Australasia #415 - December‘25

www.divelog.net.au