Membramatic® Inflatable seals
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MEMBRAMATIC® INFLATABLE SEALS

MEMBRAMATIC® INFLATABLE SEALS Catalogue

PRECISION SEALING SYSTEMS 7 MEMBRAMATIC INFLATABLE SEALS® 4 MAIN FAMILIES OF INFLATABLE SEALS 9 SELECTING AN INFLATABLE SEAL DEFINING THE GEOMETRY & THE DIRECTION OF EXPANSION12 4. CHOOSING & POSITIONING THE INFLATION CONNECTORS

MEMBRAMATIC type D Textile Obturations types Standard connector assembly Specific connectors: VL valve Profile type Seal geometry Obturation types

INTRODUCTION 1. HUTCHINSON GROUP To meet its clients’ needs on land, in the air and at sea, Hutchinson has been designing, developing and manufacturing high-performance solutions for 170 years. PRECISION SEALING STRUCTURAL SEALING FLUID MANAGEMENT ANTI-VIBRATION SYSTEMS TRANSMISSION SYSTEMS Our innovations cover a wide variety of particularly demanding markets: automotive, aeronautics, defence, energy, rail and industry in general. As a world leader in anti-vibration systems, fluid management and sealing solutions, our group stands out for its multi-market and multi-expertise approach, a...

2. PRECISION SEALING SYSTEMS As a leading manufacturer of sealing solutions, Hutchinson - Precision Sealing Systems designs and manufactures static and dynamic sealing solutions, magnetic washers, absolute rotary sensors, foams and composites for its international clients operating in a wide range of industrial sectors. Our range of MEMBRAMATIC® inflatable seals meets the requirements of the most demanding environments such as nuclear, aeronautics & space and defence. We have complete control over the whole process – from development to production – meaning we can provide our clients with...

MEMBRAMATIC® INFLATABLE SEALS 1. APPLICATIONS Inflatable rubber seals provide sealing for installations with moving components, possibly ones on which there is a significant variable range of movement. They mitigate irregularities in the construction process and distortions on the various surfaces of the assembly to be sealed. They address problems associated with tightening components and can be used for clamping, pressing, gripping or handling a given device. Based on a simple, safe and effective technology, they offer numerous advantages over conventional seals. They solve previously...

2. OPERATION Supplying a pressurised fluid, usually a gas inside the seal, activates it and shifts it from the resting position to the operating position. Releasing the pressurised fluid in the seal returns it to the idle position thanks to the elasticity of the elastomer. The seal resumes its original shape. The internal pressure of the fluid contained in the seal results in a contact on the interface to be sealed that creates the watertightness / gas tightness. This pressure must always be higher than the pressure to be sealed (+0.2 to +1 bar, depending on the types of inflatable seals...

SELECTING AN INFLATABLE SEAL An inflatable seal should be chosen when the gap to be sealed is significant or variable. To obtain a satisfactory level of watertightness / gas tightness with an inflatable seal, go through the following steps when selecting the seal. The most appropriate profile should be selected, based on operating and assembly conditions: the gap and the pressure to be sealed. Use the following table to choose from among the various standard profiles in our catalogue. Profile type 2. RUBBER SELECTION The main factors to be taken into account when choosing the material are:...

Basic elastomer Min. & Max admissible temperature for our seals (°C) Textile reinforcement Main properties and applications Cold resistance Demineralised water resistance Aliphatic hydrocarbon & medium aromatic resistance Atmospheric ageing, aliphatic & weak aromatic hydrocarbon resistance Acid & alkalis, hot water resistance Excellent impermeability to air & other gases in general Same as butyl with better temperature resistance Acid and alkalis, hot water, intermediary temperatures & radiation (nuclear use) resistance EPDM – Ethylene propylene Resistance to extreme temperatures (high &...

3. DEFINING THE GEOMETRY & THE DIRECTION OF EXPANSION The geometry of the seal depends on the shape to seal. We have 4 possible scenarios: − Ring seal: C geometry − Closed frame seal: F geometry − Linear seal: L geometry − Open seal with angle(s): U geometry The direction of expansion is defined as below: − External Expansion : E Type − Internal Expansion : I Type − Front axial expansion : F Type E Type direction of expansion I Type direction of expansion F Type direction of expansion In all cases, the radius of curvature that is compatible with the geometry and direction of expansion must...

4. CHOOSING & POSITIONING THE INFLATION CONNECTORS Fluid usually enters the inflatable seal via a metal connector or valve which can be connected to the main supply circuit of the device to be sealed, see p.29. Pressurised fluid can be supplied by various devices such as a general compressed air circuit, compressor, bottle, tank, etc. Supply connectors are made of either brass or stainless steel (special metal connectors may be considered on request). Inflation connectors are attached to the seal either mechanically or by over moulding. The connector is usually mounted in the back of the...

GENERAL RECOMMENDATIONS 1. CALCULATION OF STRUCTURES The structures must be sized taking into account the force applied by the inflatable seals when activated. This force will be evaluated by the formula: F: Force in DaN (decaNewton) over a given length Width of a section of the seal in cm Internal pressure of the seal in bar 2. DEFINING THE GROOVES The groove should be chosen based on the gap to be compensated for and the space available once the profile to be used has been defined. See p.20 to 24. In general, the not inflated seal should be withdrawn relative to the top of the groove. The...

For all supports, we recommend a Ra < 3.2. This value generally provides a good compromise between satisfactory sealing and reasonable cost. Better surface condition will ensure better sealing. 4. DEFINITION OF FASTENINGS The profiles shown here are without heels; unless otherwise stated, they are bonded into the groove. We can provide profiles for mechanical fastening on request. Note: for bonding the seals, see point 2.3, p.18. 5. INFLATION SUPPLY It is advisable to have a permanent inflation pressure for the seal. The pressure must be controlled by a pressure regulator so that pressure...