Dealing with pressure 22 January 2019

By Gail Friedberg, vice-president, ZAGO Manufacturing Company

Engineers are often unclear about the utility of self-sealing fasteners versus ordinary screws, nuts and bolts. Why use a more expensive sealing fastener when a standard fastener or a non-grooved fastener with an O-ring or washer will do? The reason – pressure.

Pressure is everywhere. Even at sea level atmospheric pressure is equal to 14.70 pounds per square inch or 1.03 kilos per centimetre. Inside equipment, particularly hydraulic and pneumatic equipment, pressure rises quickly after activation. Similarly, as an aeroplane rises in the air, outside pressure increases; and as a robot dives below the surface of the sea, pressure increases precipitously. Standard fasteners simply cannot withstand this pressure. Leaks of gases and liquids are sure to follow, leading to equipment failure and environmental degradation. A mechanism is necessary to counteract this pressure.

The best possible mechanism to prevent leaks due to pressure, and the infiltration or egression of liquids and gasses, is a fastener with an O-ring and a groove. Using a simple O-ring or washer to seal, without a groove calculated to relieve pressure, will inevitably lead to equipment failure. However, a accurately engineered groove will absorb the pressure within and outside of equipment that is applied to the O-ring forcing the O-ring to spread and penetrate any open space where leaks might occur.

The demand for sealing fasteners has never been greater. As equipment becomes more expensive and sophisticated, the need to keep it contaminant free is critical. Also, as environmental concerns grow, the need for an environmentally sustainable solution to equipment failure is paramount.

ZAGO self-sealing fasteners are sustainable in the broadest sense of the word. They are conflict mineral free, ROHS and REACH compliant, as well as compliant with California proposition 65. They are the ideal solution for long-term industrial and mechanical sustainability and ideal for sealing electrical enclosures and equipment subjected to the elements. At ZAGO, we are the acknowledged leader in the manufacture of self-sealing fasteners with over 25 years of problem solving engineering experience.

Claire Aldridge Deputy Editor t: +44 (0) 1727 814 450

Having joined the magazine in 2012, Claire developed her knowledge of the industry through the numerous company visits, exhibitions and conferences she attended both in the UK and abroad.

Claire prides herself on keeping readers well informed and up to date with the latest industry news.