HS Profile, Static Head Seal | Zatkoff

HS Profile, Static Head Seal

HS Profile, Static Head Seal


As mobile equipment OEM’s continue to consider warranty costs, one area of focus has been a review of down time related to cylinder head glands. Two of the most common seal failures on cylinder heads are o-ring back-up blow-out and pinched back-ups. Both failures are common in systems with high eccentricities or large extrusion gaps. To address these situations and to reduce down time HS Profile static head seals are specified to replace the industry-standard o-ring and backup. Incorporating high performance plastics with a stable, symmetrical geometry, dramatically reduces the risks of installation damage and back-up blow-out. Both problems are eliminated with the HS Profile’s one piece urethane design offering improved fit and a stable geometry.

Back-up rings are the most common anti-extrusion devices in dynamic sealing. They provide simple solutions to safely increase system pressure or solve an existing seal extrusion problem. Back-up rings function by positioning a more robust material adjacent to the extrusion gap, taking the seal’s place and providing a barrier against high pressures. Back-ups can be used to offset the reduced pressure rating effects of wear rings or to improve seal life at increased pressures. They can also be used to protect seals against pressure spikes, or to ensure seal performance at higher temperatures.

When to Use Back-Up Rings

  • System operating pressure exceeds the limitations of the seal’s extrusion resistance.
  • Pressure spikes in the system exceed normal operating conditions,risking damage to the seal.
  • The use of wear rings has increased the extrusion gap, reducing the seal’s pressure rating to an unacceptable level.
  • The system temperature is high enough to lower the seal’s extrusion resistance to an unacceptable level.

Standard Materials

  • P4700A90