What is an Inflatable Seal?

An inflatable seal is a fabric-reinforced elastomeric tube custom molded in a concave, convoluted or flat configuration. It is designed to round out with the introduction of an inflation medium to form a tight barrier between a mounting and striking surface. For example, see the cross section illustration below. Position A shows the molded configuration and Position B depicts the inflated configuration.

How Does an Inflatable Seal Work?

Upon introduction of the inflation medium, it quickly expands to the striking surface, effecting a positive seal. When the inflation medium is removed, the seal retracts naturally to the deflated "memorized" configuration. This position provides clearance for free movement of one or both surfaces.

How is and Inflatable Seal Inflated?

The most common inflation medium is regulated air. The specific parameters of the application determine the optimum operating pressure. In some applications, liquid or gel may be used as the inflation medium. Introduction of the inflation medium is through a stem which is usually a flexible hose secured to an integrally molded fitting with a ferrule. A variety of fittings may be attached to the end of the hose.

Why Use an Inflatable Seal? An inflatable seal has several advantages over other sealing methods:

  • It provides a leak-proof closure, yet allows clearance when needed.
  • It simplifies the design of the structure and hardware.
  • It minimizes the need for close machining and/or fabricating tolerances.
  • It is not subject to compression set which negates effectiveness of other seals.

Inflatable Seal Geometry

Inflatable seals can be installed in different planes; radially in, radially out, axially and any combination thereof. They will conform to many different contours. They are made in strips with closed ends or in continuous loops. The bend radii will vary from seal to seal and if a very sharp or mitered corner is necessary, the seal can be molded to the exact configuration.