Inflatable seals

Inflatable seals, Airseal high temperature silicone

Inflatable seals, EPDM

Inflatable seal: EPDM, corner profile

Inflatable seals, FDA, antibacterial

Inflatable seals, round, silicone, blue, VA flap

Inflatable seals, round, natural rubber, red

Inflatable seal: round, EPDM, moulded article, tube connection1

Inflatable seals, round, EPDM fabric reinforcement

Inflatable seals, round, EPDM, FDA, electrically conductive

Inflatable seals, round, made of natural rubber, FDA

Inflatable seals, round, made of silicone, FDA, series function

Inflatable seals, round, FDA, silicone, brass connection

Inflatable seal: HNBR, automotive industry, cable construction

Inflatable seal: air connection valve

Inflatable seal: straight, bulkhead seal

Inflatable seal: straight, NBR

Inflatable seals: Assembly cushion, pneumatic, silicone FDA

Inflatable rectangular seal, FDA, metal support

Inflatable seal: bulkhead seal, high water protection

Inflatable rectangular seal: size comparison to Smart

Inflatable rectangular seal

Inflatable seals made of high-quality elastomers or silicone

AL Gummi produces high-quality inflatable seals in Germany, specially designed to meet your individual requirements. We develop and manufacture customised profile geometries as required. We produce seals in round, stretched or rectangular designs – for special cases also with fabric reinforcement.

Our seals are made of silicone and other common elastomers. We currently have 75 different profiles made of silicone and 25 profiles made of other high-quality elastomers in our standard programme.

Inflatable seals are often used where the possibilities of static seals are exhausted. We offer solutions through the use of different profile geometries and targeted material selection.
For example, inflatable seals are the right choice when a non-contact seal is advantageous in the closing or opening process.

Different terms are used for inflatable seals, depending on the supplier or even the region. The terms pneumatic seal, inflatable hollow chamber seal, expansion seal, roll-out seal, expansion seal, pneumatically activated profile, inflatable seal, airseal, pneuma seal or techmembrane are often used.
All these terms are synonyms for the inflatable seal.

Talk to us about your application.

Inflatable sealin round design

Extruded hollow profiles are cold or hot vulcanised endlessly into rings. In addition, we install a connection piece or a valve for the media inlet.

With this production technology, the possible bending radii depend on the profile cross-section.

For most applications of inflatable seals, ring-shaped or polygonal (corner areas with radius without exception) seals can help.

For special solutions with deviating bending radii, we can also manufacture your seals as moulded articles.

Inflatable seals: Bending radius radial, outside

Inflatable seals: Bending radius radial, inside

Inflatable seals in straight version

For the straight version, we vulcanise end plugs into the hollow profiles. The end plugs usually have a length of 20 to 30 mm. In addition, we install a connection piece or a valve for the media inlet. It is also possible to vulcanise the air connection into the end pieces.

We recommend to secure the two ends mechanically as well. This prevents the seal from being pressed out or pulled out. At the same time, such a measure extends the durability of the seal.

For the optimal design of your seal, please contact our team, which will be happy to help you select a material or the right profile cross-section.

Inflatable seals: Clamping device end part

Inflatable seals: Straight version, connection in the stopper

Inflatable seal: Main illustration S6 straight

Inflatable seal: Main illustration S13 straight

Inflatable seals with corners

We also manufacture inflatable frame seals with rounded or even 90° corners.

Inflatable frame gaskets with mitre joints regularly have high error rates. For this reason, AL Gummi + Kunststofftechnik offers square inflatable gaskets only with shaped pieces.

If uniform expansion throughout is a prerequisite for axial sealing, moulded vulcanised corners can be incorporated into the seal. In this case, the straight side parts made of pre-extruded profile are joined together by directly vulcanising the corners.

In case of radial expansion inwards or outwards, we recommend using polygonal inflatable gaskets. The radii of curvature of the profiles are decisive here. If a tighter rounding of the mould is desired, we can alternatively manufacture inflatable seals with rounded mould corners.

Another frequently used variant is inflatable seals in a U-shape. Our U-shaped seals inflate radially inwards or outwards, or seal axially upwards or downwards.

Our team will be happy to advise you on your special solutions.

Structure and functionof inflatable seals

As a rule, inflatable seals consist of an extruded hollow profile with an air connection. In particularly demanding cases, inflatable seals can also be manufactured as moulded articles. For activation, pressure is applied to the profile, which leads to expansion of the seal in a defined direction.

In addition to their use as seals, inflatable seals can also perform other functions. They can be used to solve problems that occur when lifting and lowering components. Furthermore, inflatable seals can also be used to clamp and grip elements.

So-called air seals are often used as insulators in applications where airtight sealing is mandatory. This will protect the equipment operator from the contents of the isolator, or more commonly, the process within the equipment from external contamination. Air seals are equally suitable for gloveboxes, entrance doors, transfer and filter systems where toxic or sterile components are handled, as well as for heat, chemical, radiation or filter-based sterilisers.

Hollow sectionscan basically be divided into high-pressure and low-pressure profiles

The low-pressure profiles are characterised by the fact that they are pressurised with relatively low pressure (up to 0.8bar). Low-pressure profiles are selected for bridging large distances and, depending on the profile, can overcome a distance of up to 20 mm. The path of the seal is determined by the geometry. Due to the profile, however, only low contact pressures can be realised. Low-pressure profiles are therefore particularly suitable for sealing larger sealing gaps at low pressures or for lifting low loads.

The high-pressure profiles only bridge small distances. However, they can be subjected to higher pressures
(up to 3 bar). They are expanded to a certain height by means of compressed air and return to their original size when the pressure is released. High-pressure or expansion profiles bridge considerably less distance than low-pressure profiles, but they develop higher contact pressures. Due to their usually strong construction, expansion profiles can be used to seal higher counterpressures than low-pressure profiles and are therefore particularly suitable for lifting, clamping or holding loads.

As a general rule, the smaller the sealing gap selected, the shorter the activation time. If the seals are chambered, higher pressures can also be used, depending on the application.

Blowing direction

The blowing direction is important for the optimal effect of the inflatable seal. The best clamping effect is achieved with a profile that seals radially outwards. We distinguish between three cases:

Expansion radially outwards

Expansion radially inwards

Expansion axially upwards or downwards

Profile selection

The choice of profile depends on the operating and installation conditions.
It must be clarified whether small or large sealing gaps are involved or whether high or low contact pressure is used.

In certain cases, for example with high operating pressures and large sealing gaps, we recommend the use of hose seals with fabric inserts.

Download AL profile list

Connectors and valves

We attach connecting pieces or valves mechanically or by vulcanising them to the seal.

We manufacture the air connections mainly from brass or stainless steel, on request in special metals or other alloys.

Different installation types for air connections are:

Position A

Position B

The seals are made of all common elastomers that can withstand a wide range of environmental conditions and extreme temperatures from -60 to +220 °C (even higher temperatures for short periods).

The most common materials we use are silicone and EPDM. However, we also manufacture seals made of NBR, HNBR, CR and NR/ SBR.

The material selection

We produce AirseaL seals for a wide range of industrial applications. The choice of seal and material is determined by criteria such as the individual application, ambient pressure, temperature and medium to be sealed.
After analysing the medium to be sealed, the material is selected.

The following factors must be taken into account here:

Type of gas (air, nitrogen, chlorine, etc.)
Type of liquid (water, solvent, oil, grease, acid, etc.)
Operating temperature (cold or heat resistant)
Other influences (UV, ozone, FDA compliant, electrically conductive etc.)
Pressures and pressure differences between the areas to be sealed

Maintenance methods and cleaning agents must also be considered.
These include: Detergent, soap, benzine etc.

In the pharmaceutical industry, silicone is used in standard applications, but in complex applications, special materials are also used that are designed for a long service life and ensure a lower operating risk. Furthermore, at AL Gummi und Kunststofftechnik we work with a special silicone whose impregnation of silver ions inhibits bacterial growth.
In the pharmaceutical and medical technology sector, the selection of the appropriate seal is a central component of the system design. In particular, further developments in the field of silicone compounds reduce the risk of contamination and make the seal FDA-compliant.

Silicone gaskets can be manufactured in various designs:

with a low-friction surface AL-ROB
with an antibacterial surface AL-BAK
electrically conductive silicone seals AL-LEIT
high temperature resistant silicone gaskets up to +300°C AL-TEMP
highly tear-resistant silicone AL-RES®

Despite all its advantages, the high gas permeability of silicone is a challenge. Today, there are methods to reduce the gas permeability of silicone, while at the same time reducing the absorption of foreign substances, i.e. the risk of cross-contamination. In general, this also increases the service life of the seal. Appropriate pre-treatment of the gasket also achieves a better coefficient of friction, which in turn reduces the risk of the gasket surface sticking to the mating surface.

Based on these specifications, our technical staff can make the appropriate material selection.

Here you can find the overview of materials (PDF).

AL-Gummi Branchenlösungen Pharma und Medizintechnik - OP-Raum

Pharmaceuticals and medical technology

Door and laboratory seals, glove boxes, autoclave doors, clean room seals, heating cabinets, sliding doors, sterilisers

AL-Gummi Branchenlösungen Getränke- und Lebensmittelindustrie - Fließband mit orangenen Flaschen

Beverage and food industry

Wine presses, smokehouses, brewery, cheese dairy

AL-Gummi Industry Solutions Shipping and Hydraulic Steelwork

Navigation and hydraulic steelwork

Cargo hatches, helicopter deck, lift platforms, hatch covers, bulkhead seals

AL-Gummi Branchenlösungen Verkehr und Logistik - Zug der Deutschen Bahn in Bewegung

Transport and logistics

Sliding doors, panelled doors, railway carriage doors, aircraft doors

AL-Gummi Branchenlösungen Anlagen- und Maschinenbau

Plant and mechanical engineering

Filling systems, silos and silo trucks, container seals, drum presses, refrigerated containers, storage containers, material locks, washing systems, robotics accessories, filter system

AL-Gummi Branchenlösungen Dosier-, Schüttgut- und Recyclingindustrie - Körner eines Rohstoffes in Händen

Dosing, bulk solids and recycling industry

Powder and granules, mixing and screening plants, dryers, flaps, valves, screen changing systems

AL-Gummi Branchenlösungen Industrieöfen und Vakuumtechnik - Autoklav

Industrial furnaces and vacuum technology

Vacuum seals, autoclave seals, tempering ovens

Energy and environmental technology

Door and hatch seals, cooling water seals, tank seals

Architecture and construction industry

Flood protection/ door and window seals