The History Of Industrial and Manufacturing Processes

Rubber O-rings have long been the standard for liquid and gas seals in industrial applications. While standard O-rings are still an excellent choice for non-dynamic applications, quad-ring seals are often preferred in systems with high levels of linear or rotary force. This guide will explain several benefits of rubber quad-ring seals.

1. Higher Sealing Contact Area

The contact area of any seal determines the quality of the seal and the amount of pressure it can withstand. Quad-rings improve upon O-rings because they allow a much larger contact area for the same amount of material. The lobes of a quad-ring compress so that they are all in contact with the sealing surface.

The high surface area of a quad-ring also allows less compression force to be used to create the seal. 50 durometer O-rings with a diameter of just 0.07 inches can require as much as 14 pounds per linear inch of force.

Since each lobe on a quad-ring is a separate point of contact, quad-rings do not have to be compressed as much as O-rings to seal properly. Lower compression force reduces the rate of wear and tear, so quad-rings can often provide a much longer effective life than O-rings.

2. Less Prone to Spiral Failure

Spiral failure occurs when a rubber seal twists until it can no longer withstand the strain and tears. Spiral failures are common in linear sealing applications, where force is applied along a perpendicular axis to the seal. O-rings are naturally susceptible to spiral failure because of their round shape, which allows them to easily roll along the linear axis within the groove.

Quad-rings are more resistant to spiral failures than O-rings because their wide, square-shaped base makes them less prone to rolling. Furthermore, quad-rings can often be installed in narrower grooves than O-rings, which gives them less space overall to roll around in.

3. Better Lubricant Retention

Proper lubrication is essential to maintain the effective life of any rubber seal. The design of an O-ring is not conducive to retaining lubrication, as the lubricant can easily roll off of the rounded surface of the ring. Both linear and rotary movements of an O-ring can create friction if there is not enough lubricant present.

The four grooves between the lobes of a quad-ring are excellent for locking the lubricant in place. This makes quad-rings a great solution for rotary sealing or seals that are applied to a polished metal surface that can easily lose lubrication. 

4. No Parting Line Interference

The parting line is the small ridge of material that is present on the inner and outer edges of an O-ring. Parting lines occur due to the rubber seal manufacturing process. The parting line forms where the two halves of the mold meet.

Parting lines can be problematic in some sealing applications because they create an irregular surface that can interfere with the seal. When the parting line is compressed unevenly beneath an O-ring, it can leave enough space between the seal and the adjacent surface to allow gas or liquid to seep through.

Unlike O-rings, which have parting lines on each side of their exterior, quad-rings can be manufactured with recessed parting lines. Quad-rings are molded in such a way that the parting lines are recessed in the grooves between the lobes. This way, the lobes create a tight seal on either side of the parting line to prevent unexpected leaks.

With only a minor change in the cross-section of the seal, quad-rings improve upon O-rings in many ways. Keep these tips in mind if you are searching for a dynamic sealing solution so you can find the seal that is best suited for your particular application.

To learn more, contact a company like Rothkopf.