Parker Integral Seal
The Integral Seal is so named because it effectively integrates a stamped or machined metal or molded plastic retainer with a moldedin-place rubber sealing element to create an extremely versatile sealing device.
- Fast assembly.
- No blow out.
- Visually detectable after assembly.
The Integral Seal is so named because it effectively integrates a stamped or machined metal or molded plastic retainer with a molded in-place rubber sealing element to create an extremely versatile sealing device. The Integral Seal is custom designed, versatile and provides similar performance benefits seen with Parker’s Gask-O-Seal.
The Integral Seal lends itself to space constrained applications where overall seal thickness may be of primary concern. Integral Seals can be manufactured in thickness as low as 0.012″. The Integral Seals design also lends itself to high volume manufacturing methods making it a cost competitive option for high volume sealing applications. As shown below, the rubber sealing element is molded, and mechanically and/or chemically, bonded in place to the edge of the retainer.
Integral Seal Design Considerations
Once the seal type is determined the actual design for the Integral Seal can be started. There is a simple step by step method for designing an integral seal for your application. Here are the key points to consider:
1. Metal Thickness
Whenever possible, the metal thickness should be specified as a standard gauge callout with an accompanying standard stock thickness;
i.e., Steel 11 gauge (.120″ stock). This allows Parker to use materials that are readily available from suppliers and are most economical in producing the finished Integral Seal. Capabilities exist to go down to .012″, however, metals with a thickness of less than .090″ should be discussed with the Composite Sealing Systems Division’s engineering department.
2. Dimensional Tolerances
In developing the overall design and establishing tolerances, the noncritical features, such as outline or outside dimensions, should have wide tolerances to reduce manufacturing costs. Bolt holes should have sufficient clearance around the bolts to permit reasonable locating tolerances. However, when the seal groove is located in relation to the bolt holes, the holes should be located within O .014 on small parts (<10 inches).
In order to achieve optimum sealing, it is essential to provide sufficient flange preload and proper bolt size and spacing to create a metal to metal contact between the Integral Seal retainer and the mating parts.
Under all service conditions, such as out-of-flat, system pressure, and rubber strength, the separation between flanges should not exceed .003″ in order to prevent extrusion and damage to the elastomer. The force required to compress the seal is generally between 30 and 150 pounds per linear inch of seal, depending on the rubber durometer, material, and the configuration used. For larger gaps contact the Composite Sealing Systems Division’s engineering department.
4. Surface Roughness
Surface roughness of the Integral Seal retainer itself is not critical to sealing. When a sheet metal retainer is used, the “as received” condition of the metal is satisfactory. On machined surfaces, Parker will maintain a roughness value of 125 micro-inch Ra or better. Callouts for finishes of the Integral Seal retainer with roughness less than 125 Ra can unnecessarily add to the part cost. For mating surfaces that the Integral Seal is to seal against, a 125 Ra or better will provide good sealing surfaces for almost all applications. The only noteable exceptions are seals for gaseous media where diffusion type leakage must be kept to a minimum. For these installations, the mating surface should have a finish of 32 Ra or better.
5. Flatness and Parallelism
In most cases, no particular attention needs to be given to flatness and parallelism requirements. Occasionally the Integral Seal is used between two halves of a device that must be accurately, aligned such as a gear box housing. For this, the mating surfaces must be parallel within close tolerances.
6. Flange Separation
When pressure is applied to a separable joint of any kind (e.g. flanges, lids, covers, etc.) there is a tendency for the mating surfaces to separate or “gap”. This gap can result in extrusion, wear and failure of the seal element. Ascertain whether the existing flanges or covers separate, gap, or bulge during pressurization and/or cycling. This will determine seal cross-section, crown height, style, and re-enforcement required once you know the magnitude.
7. Types of Bond
During the molding-in-place process, the carefully designed seal element is either chemically bonded to and/or mechanically interlocked with the edge of the metal (or plastic) retainer.
- Chemical Bonding – For the sizes equal to or larger than 1″ inside diameter, a chemically bonded retention of the rubber seal element is provided. This bonding takes place during the actual molding-in-place of the rubber via a process called co-vulcanization. This assures excellent adhesion of the seal element.
- Mechanical Interlocking – A unique mechanical type retention of the molded-in-place rubber to the metal retainer is available. During the stamping operation, the inside of the retainer/washer is splined and then coined to provide a series of interlocking openings for the securing of the rubber as it vulcanizes in place.
8. Retrofit with Parker’s Integral Seal
Integral Seals can be adapted to retrofit existing flange designs that already have an O-ring groove or counterbore for complete interchangeability. The retainer thickness can be reduced to as low as .012″ to facilitate retrofitting in previously grooved flanged surfaces
9. Finite Element Analysis (FEA)
The study of elastomer stress and its relationship to seal effectiveness has been dramatically enhanced with the advent of finite element analysis. FEA is a numerical modeling technique used to predict a deformation and stress concentration of a given seal cross section.
Parameters such as cross section geometry and material property data are factored into the modeling equation to produce a stress concentration model of the seal. FEA is effective as a predictor of seal performance only when it is used in conjunction with historical seal and material data and specific performance testing. Please consult the division if FEA is being considered as a tool for seal design.
The retainer permits extremely fast and sure installation. In fact, where volume dictates, the placement of the seal can be fully automated on a completely foolproof basis.
• Bolt retention: The rubber can be molded on the bolt holes for positive pre-assembly gripping and transporting. Retainer fits conveniently over bolts to hold the seal in place during assembly the seal cannot fallout.
• Fast assembly
• No blow out
• Visually detectable after assembly
• Resists extrusion under high pressure and flange separation
There are five Integral Seal types to suit specific customer design requirements. Like the Gask-O-Seal, configurations available to the user are quite varied and are limited only by retainer dimensions and space considerations. It is even possible to segment certain Integral Seal styles using a Parker devised tongue-and-groove arrangement to seal extra large layouts. Consult the division for further details concerning such special applications.
This warranty comprises the sole and entire warranty pertaining to items provided hereunder. seller makes no other warranty, guarantee, or representation of any kind whatsoever. All other warranties, including but not limited to, merchant ability and fitness for purpose, whether expressed, implied, or arising by operation of law, trade usage, or course of dealing are hereby disclaimed. Notwithstanding the foregoing, there are no warranties whatsoever on items built or acquired wholly or partially, to buyer’s designs or specifications.
Limitation of remedy: Seller’s Liability arising from or in any way connected with the items sold or this contract shall be limited exclusively to repair or replacement of the items sold or refund of the purchase price paid by buyer, at seller’s sole option. In no event shall seller be liable for any incidental, consequential or special damages of any kind or nature whatsoever, including but not limited to lost profits arising from or in any way connected with this agreement or items sold hereunder, whether alleged to arise from breach of contract, expressed or implied warranty, or in tort, including without limitation, negligence, failure to warn or strict liability.
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