PLASSON seals the deal with a clever tweak
PLASSON took the original O-ring from 1896 and did something simple but clever with it. By placing the O-ring into a special groove machined into the inside of each fitting, the PLASSON O-ring is always in the optimum position for sealing.
This innovative design means the fitting seals water-tight as soon as the pipe passes through the O-ring. With PLASSON compression fittings, you only tighten the nut to prevent the pipe and fitting from moving apart, or blowing out, under pressure. The design also means the O-Ring can’t fall out and be damaged, contaminated or lost during installation.
The O-ring is a donut-shaped ring (technically, a toroid) with a circular cross section made from different elastomers.
PLASSON compression fittings can have Nitrile NBR O-rings or EPDM O-rings, which has a better chemical resistance than NBR, or Vitron seals, which offer better chemical resistance than EPDM.
The name Viton is a trademark and refers to fluorocarbon O-rings, or FKM/FPM for short. This material has an excellent tolerance for high temperatures, resistance to oils, fuels and hydraulic fluids as well as aromatics and solvents.
O-rings seal by mechanical deformation (caused by compression) which creates a barrier to a fluid’s potential leak path between two closely mated surfaces.
Applying fluid pressure pushes the O-ring against the groove wall on the low-pressure side, increasing the sealing force.
At higher pressures, the O-ring deforms to a “D” shape, increasing the contact area further.
How PLASSON engineered a fitting to be “O” so reliable
How PLASSON compression fittings work is a bit of a yarn that starts way back in 1896. Unless you are a trivia junkie, it will probably come as news that one of the most critical precision mechanical components ever developed was patented on May 12, 1896. That was when a Swedish patent for the O-ring was awarded to J.O. Lundberg. Niels A. Christensen was granted a US patent for his O-ring design in 1937.
Like all good ideas, it came to the attention of some pretty big players. The O-ring quickly became the standard seal for hydraulics in the military. The top brass set out the standard sizes and basic design guidelines that remain in use today.
The humble O-ring delivers a reliable seal through compression and that is why PE pipe joiners that seal via O-rings are described as compression fittings.