O-ring seal

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Introduction
Seal Master Corporation is an industry leader in custom engineered, fully molded, fabric-reinforced inflatable seals and bags designed for demanding, regulated and industrial applications. This guide provides an overview of critical factors that impact inflatable seal design including geometry, seal configurations, application geometry, air connections, retaining systems, control devices, environmental considerations, and construction/materials.

Geometry
Seal Master inflatable seals operate and inflate in three principal directions: axial (normal to the mounting plane), radial-in, and radial-out. Each direction has performance parameters such as inflation height (stroke) and allowable centerline bend radius. These performance parameters are influenced by the cross-section geometry of the seal.

Typical Inflatable Seal Configurations
There are many cross-section configurations developed to meet a wide range of industrial, research, and military requirements. Profiles are selected for their performance in particular inflation directions and are further differentiated by retention method.

Common Retention / Configuration Types

• Snap-In Type: Dovetail-style base that snaps into a matching retainer groove. Quick installation and replacement; retainer provides support and protection.
• Bond-In Type: Installed into a straight-wall groove and bonded into place; useful where a bonded mounting is preferred.
• Encapsulated Type: Seal captured by bar stock or specially formed channel; an inflatable tube actuates a solid rubber shoe to the striking surface.
• Fasten Type: Uses metal fasteners (bars, pins, clips) which can be tack welded or screwed to the mounting surface.
• Recessed Groove Type: Typically used with smaller diameters in radial modes and held by tension/force; studs can be used for larger diameters.
• Drop-In Type: Designed to be dropped into a groove or gap and retained by gravity and geometry without additional hold-down devices.

Define Your Application Geometry
Two major considerations determine the seal profile: geometry and environment. Defining geometry includes available mounting space, required stroke, how the seal will be placed, and mechanical function. A sketch or drawing of the application is highly useful to determine appropriate profile and mounting approach.

Typical Air Connections
Air connections are integrally molded into Seal Master inflatable seals, providing high strength and construction integrity. Base-location and access for the air feed should be considered during design.

Inflatable Seal Retaining System
Proper installation is essential. A retainer must hold the seal in place, allow free inflation/deflation, and protect the seal from damage. Seal Master can provide metal or elastomeric retainers in strip or circular form. Alternatively, seals can be retained via machined grooves in the application.

Control Devices
Some applications require controlled or cycled operation. Control solutions can include control boxes, valves, regulators, gauges, alarms and compressors. Seal Master can provide control devices for applications that require them; such devices are used, for example, to operate seals in emergency rescue vehicles or other process-critical systems.

Application Environmental Considerations
Environmental conditions drive selection of elastomer compounds and fabric reinforcement. Conditions to record include temperature range, chemical exposure, abrasion, UV exposure, ozone, and other mechanical stresses. Material selection is made collaboratively between the customer and Seal Master engineers based on application needs.

Construction & Materials
Seal Master inflatable seals are custom built, fabric-reinforced and fully molded rather than simple extrusions. Multiple combinations of elastomers and reinforcement fabrics are used to meet geometry and environmental challenges. Typical elastomers and fabrics used are listed below.

Typical Elastomers Used

• Butyl
• Chloroprene
• Epichlorohydrin
• Ethylene-Propylene
• Fluorinated Hydrocarbon (Viton®)
• Natural Rubber
• Nitrile (Buna N)
• Polyurethane
• Silicone
• Styrene-Butadiene (Buna S)

Typical Reinforcement Fabrics

• Dacron
• Kevlar®
• Nomex®
• Nylon

Custom Inflatable Seals
Seal Master produces custom engineered inflatable seals; thousands of unique profiles have been developed to meet varied requirements. The specific profile, materials and retaining method are determined by the application performance requirements.

Technical characteristics / Specifications

• Manufacturer: Seal Master Corporation
• Product type: Fabric-reinforced, fully molded inflatable seals and bags
• Typical inflation directions: axial, radial-in, radial-out
• Retention options: Snap-In, Bond-In, Encapsulated, Fasten, Recessed Groove, Drop-In
• Air connections: integrally molded into the seal
• Control devices: valves, regulators, gauges, alarms, compressors (available when required)
• Typical elastomers: Butyl, Chloroprene, Epichlorohydrin, EPM, Viton®, Natural Rubber, Nitrile, Polyurethane, Silicone, SBR
• Typical fabrics: Dacron, Kevlar®, Nomex®, Nylon
• Customization: profiles are custom engineered to application geometry and environment; thousands of unique configurations exist
• Main representative image: https://www.sealmaster.com/wp-content/uploads/2020/05/inflatable-seals-101-featured-img.jpg