Inflate to seal — deflate to release. A practical guide to inflatable seals: how they work, when to use them instead of compression seals, materials, and design basics.
An inflatable seal is a custom-engineered elastomer seal that uses air or gas pressure to expand against a mating surface, creating an airtight, watertight, or gas-tight barrier. When deflated, the seal fully retracts — allowing repeated access for doors, hatches, chambers, and processing equipment.
Unlike a conventional gasket or O-ring, an inflatable seal supplies its own sealing force. That single difference is why it solves applications where static seals fail: irregular surfaces, variable gaps, and openings that must be sealed and released thousands of times.
Compressed air or gas enters through an inlet valve, expanding the seal outward from its groove or retainer.
The seal presses against the mating surface, conforming to irregularities and bridging gaps that static seals cannot.
Releasing the pressure fully retracts the seal below the sealing surface, giving complete clearance to open the door or hatch.
Clean, dry compressed air is the standard inflation medium; nitrogen is used for inert environments. A common sizing rule: inflation pressure runs about 1.25× to 1.45× the pressure differential across the seal — and where there is no differential, roughly 15 psig (1 bar) is typically sufficient.
The most common question engineers ask. A compression seal needs external clamping force and a consistent gap. An inflatable seal brings its own force and adapts to the gap it finds.
| Inflatable Seal | Compression Seal / Gasket | |
|---|---|---|
| Sealing force | Generated internally by air pressure — no clamping needed | Requires external mechanical clamping or bolting |
| Gap tolerance | Conforms to irregular surfaces and variable gaps | Needs a uniform, tightly-toleranced gap |
| Repeated access | Retracts fully when deflated — ideal for doors and hatches | Opening/closing wears the seal; compression set over time |
| Thermal movement | Accommodates gaps that change with thermal expansion | Gap changes can cause leaks or over-compression |
| Best for | Doors, hatches, autoclaves, clean rooms, processing equipment, variable gaps | Static joints with fixed geometry and clamping available |
Extruded homogeneous rubber profiles bonded into custom shapes — the most versatile and cost-effective option. Operating pressures up to 1–5 bar, any cross-section profile, straight runs, endless loops, or molded corners at any angle. Best for standard gaps, moderate pressures, and cost-sensitive applications.
Fully molded seals with internal fabric reinforcement — Kevlar, fiberglass, nylon, or Dacron — for significantly higher pressure capacity and cycle life. They withstand heavier loads on the seal face and can perform without an enclosed groove or retainer. Best for high pressure, extreme cycle counts, and harsh environments.
See all inflatable seal products and configurations, including bladders, small- and large-diameter seals, and valve options.
Start with the media the seal will contact and the temperature range it must survive — that narrows the elastomer. Then pressure requirements determine whether fabric reinforcement is needed.
| Material | Temp Range | Best For | Avoid |
|---|---|---|---|
| EPDM | –40°F to +300°F | Steam, hot water, ozone, weathering, outdoor exposure | Petroleum oils, fuels, hydrocarbon solvents |
| Silicone | –65°F to +450°F | Extreme temperatures, clean rooms, FDA/food contact, medical | Steam, high-pressure abrasion |
| Neoprene | –40°F to +230°F | General purpose, moderate oil resistance, flame resistance | Strong oxidizers, ketones, chlorinated solvents |
| Nitrile (NBR) | –40°F to +250°F | Petroleum oils, fuels, hydraulic fluids, grease | Ozone, weathering, ketones |
| FKM (Viton) | –15°F to +400°F | Aggressive chemicals, fuels, acids, high temperature | Ketones, low-molecular-weight esters |
| Butyl (IIR) | –40°F to +250°F | Gas impermeability, vacuum sealing, vibration damping | Petroleum oils, hydrocarbon solvents |
Browse the seal profile library to find a cross-section that matches your groove, or send us your dimensions and we will design one.
For the full engineering reference — groove tables, pressure guidelines, mechanical property comparisons — download the Inflatable Seal Design Guide.
An inflatable seal is a custom-engineered elastomer (rubber) seal that uses air or gas pressure to expand against a mating surface, creating an airtight, watertight, or gas-tight barrier. When deflated, the seal fully retracts, allowing repeated access for doors, hatches, chambers, and processing equipment.
Compressed air or gas is introduced through an inlet valve, inflating the seal and causing it to expand against the mating surface. The seal conforms to surface irregularities and bridges variable gaps. Releasing the pressure fully retracts the seal, providing clearance to open the door or hatch.
A compression seal (gasket or O-ring) requires mechanical clamping force to squeeze it against a fixed, uniform gap. An inflatable seal supplies its own sealing force from internal air pressure, so it needs no clamping, tolerates irregular and variable gaps, and retracts completely when deflated. Inflatable seals are the better choice for doors and hatches opened repeatedly, uneven surfaces, and gaps that change with thermal expansion or tolerances.
A common rule of thumb is an inflation pressure of 1.25 to 1.45 times the pressure differential across the seal. With no differential (such as a dust seal on a door), about 15 psig (1 bar) is typically sufficient. Non-reinforced seals generally operate up to 1–5 bar; fabric-reinforced seals handle higher pressures.
Common elastomers include EPDM (steam, hot water, weathering), silicone (extreme temperatures, FDA/food and medical), nitrile (oils and fuels), FKM/Viton (aggressive chemicals and high heat), neoprene (general purpose), and butyl (gas impermeability and vacuum). Fabric reinforcement options include Kevlar, fiberglass, nylon, and Dacron polyester.
Cycle life depends on inflation pressure, deflection per cycle, temperature, chemical exposure, and surface condition. Staying within the rated pressure range, minimizing over-deflection, choosing a compatible compound, and using fabric reinforcement for high-cycle applications all extend service life.