Solving product performance challenges is just one of the many services we provide our customers.  And in this recent example, we had to think outside-the-box and provide an alternatively shaped molded rubber part to fill the o-ring groove and stop the leak.

The O-Ring Groove Challenge

An engineer at one of our customer’s recently reached out for our help in identifying and solving the cause of an intermittent leak with one of their gas regulators. The issue seemed to occur early in the process when empty tanks were filled. When describing the condition, the customer reported that the o-ring appeared to be “fluttering” during the tank fill/refill process. They rightly determined that until enough pressure built up within the tank, the regulator leaked.  Finding a solution to remediate the issue wasn’t forthcoming. Concern.

They found no defects in workmanship in the o-ring, or any of the regulator valve components, and the existing fluorosilicone standard-size O-Ring Seal met all material compound specifications.  Frustration.

Meanwhile, the ongoing effects of this issue negatively impacted their business in measurable ways.  They were losing profits due to the leak of their raw material (gas). The inconsistent fill times caused delays in production. The uneasiness in management conversations around the issue – in an otherwise rock solid product line – was growing more intense. Ugly.

Our investigation revealed

  • The “fluttering” issue always occurred at the beginning of the fill/refill process.
  • When the tank was full (pressurized), there were no leaks.
  • The regulator functioned properly during the consumption of gas from the tank.
  • However, once the tank was emptied, during subsequent filling the “fluttering” issue reoccurred.

Our Determination

  • The “fluttering” issue indicated an inconsistent or insufficient seal which allowed gas to escape around the o-ring seal.
  • The o-ring moving within its’ groove was the cause of the “fluttering” as reported.
  • The “fluttering” ceased only after enough gas was present in the tank (behind the regulator) to sufficiently pressurize the system.

These facts informed us that the current seal groove design did not provide adequate surface contact between the regulator valve o-ring groove, the o-ring, and the regulator valve body.

One of two things required modification: Either change the dimensions of the regulator’s seal groove or utilize an o-ring with a differently shaped cross-section that provided more surface sealing contact within the existing groove.

Our Solution: Modify O-Ring Shape

We presented our findings, and the customer informed us that a redesign of the regulator was not a viable option due to the significant engineering time, regulatory certification and compliance testing, and retooling costs required.

Locked into the dimensions for the existing regulator valve groove, we determined the best option was not a standard o-ring but a custom molded rubber part with an oval cross-section.  The “oval-ring” design was an all around winner.

  • The new oval shaped “o-ring” remained “seated” during the fill/refill process.
  • This solved the production delays caused by the “fluttering” problem and eliminated the loss of raw material.
  • The oval-ring was manufactured from their existing fluorosilicone material compound, which avoided the recertification costs and production delays for regulatory compliance.
  • And the minimal one-time tooling cost was more than offset by the savings recouped by eliminating the loss of raw materials(gas).

Problem Solved, Leak Sealed, and Solution Delivered.