H-Seals: The most reliable static metal seal in existence and the first to allow interchangeability with elastomeric O-rings.

Easy to retrofit into existing gland designs, H-Seals are 100% reliable in extreme UHV and UHP conditions (10-13 torr - 20,000 psi), particle free, impermeable to moisture and operate from cryogenic to 500+ºC. H-Seals perform better than c-seals, delta seals or spring seals and have a significantly lower overall cost of integration. They are easy for assemblers to handle in production and cleanroom environments.

 Leak Tight: 10-13 torr - 20,000 psi
 Easy to retrofit
 Seals first time, everytime: 100% Reliable
 Cryo to 500+C

Why Use H-Seals

100% yield: The number one advantage of H-Seals is that they work 100% of the time, all the time. Anyone who has ever used traditional metal o-rings, c-seals or energized seals knows the struggle of working with delicate, highly polished surfaces. Even microscopic scratches can cause leaks and manufacturing yields can be low, often under 50%. This is frustrating for assemblers, time consuming due to rework, and costly.

H-Seals are robust and production ready: H-Seals and H-Glands were designed for the rigors of production. With recessed critical surfaces, both can be slid across flat work surfaces, edge bumped, indelicately handled and misaligned without being damaged. H-Seals do not need to be tightened to precise torque values - operators simply need to tighten by hand-feel until the assembly bottoms. H-Seals fall into place automatically without the need for retainer rings, which is easier for assemblers and speeds production. Because the H-Gland interchangeably accepts o-rings, elastomers can be used for pre-final manufacturing stages or testing, with the H-Seal being inserted at the final manufacturing step. All of these points make H-Seals the easiest to work with metal seals in existence.

Low cost of conversion and integration: With standard sizes based on o-ring dimensions, H-Seals require a small footprint and can be easily integrated into most designs.

Easy to machine gland: The knife edge is single point machined to a 16RA finish with a continuous pass that pushes all burrs to the outside. Lapping, polishing and post machining clean-up is not required. Minor irregularities on the knife edge are absorbed by the H-Seal.

Who Uses H-Seals

Customers typically convert to H-Seals from elastomers for one or more of the following reasons:


The unique H-Gland allows metal H-Seals or elastomeric O-rings to be used interchangeably.

When used with a metal H-Seal, the opposing knife edges penetrate the H-Seal web as the glands are brought together to form a high integrity vacuum seal capable of 10-11 atm-cc/sec-He or 20,000+psi. Tooth penetration into the H-Seal continues until the gland bottoms on the H-Seal flange, which acts as a positive stop and prevents over-tightening.

When used with an O-ring, the elastomeric seal seats on the recessed gland grove as it normally would.

With H-Seals, you gain instant metal seal performance but retain backward compatibility with O-rings allowing your inventory to do double-duty, which saves money and manufacturing complexity.

Interchangeability Benefits you three ways

1. Reduced Inventory
O-Rings are directly interchangeable with H-Seals, which means a single item of inventory can be used for both elastomeric and metal-sealed applications.

2. Increased Manufacturing Efficiency
The H-Seal gland allows you to use elastomeric seals for intermediate or pre-test manufacturing stages, then insert H-Seals for final assembly.

3. Design Conformity
H-Seals conform to standard elastomeric O-Ring dimensions, so there are minimal dimensional adjustments needed.

Engineering & Manufacturing Benefits

1. Self Aligning

Retainer rings not needed which simplifies assembly and saves money.

3. Tolerates Misalignment

H-Seal tolerates significant misalignment without performance loss.


2. Positive Stop

H-Seal provides a positive stop and prevents overtightening.


4. Recessed Surfaces

Critical sealing surfaces on both the H-Gland and H-Seal are recessed and protected from damage. Parts can be placed flat on an assembly table without the tooth being knicked or scratched.

H-Seals: Superior in 8 Significant Ways

Machining The H-Gland and Tooth

H-Seal & Gland Dimensions - English
H-Seal & Gland Dimensions - Metric

To get started, download H-Seal Size & dimensions PDFs.

Machining Notes