FR2811057A1 - Inflatable envelope has frame with tube receiving casing and flexible envelope formed of elastic material to define pocket - Google Patents

Abstract

The inflatable envelope has a frame (2) with a tube (2A) receiving a casing (2B) closing the interior of the tube and fixed to it. An envelope proper is made of flexible elastic material formed as a sleeve defining an inflatable pocket (100). The ends of the envelope are fixed to the inner face (2C) of the tube forming the frame and the inner ends of the tube. Claims include a method of use for the inflatable envelope.

Description

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  INFLATABLE DEVICE AND METHOD OF USING THE SAME

  The invention relates to an inflatable device.

  It also relates to a method of using the inflatable device.

  In particular but not exclusively, it is known to use an inflatable device for closing a pipe which, after having been introduced into the pipe to be closed, is inflated so that its side wall is applied with

  a predetermined force on the internal face of the pipe.

  An inflatable device is known (FR-A-2,589,580) comprising: - a frame constituted by a tube inside which is fixed, at a distance from the ends, a flange closing the interior and - fixed on this tube, a flexible elastic envelope delimiting with the tube a

inflatable pocket.

  By introducing air into the inflatable bag, the flexible envelope is pressed onto the internal face of the pipe and then forms, with the flange of the frame, a

plug or shutter.

  The elastic envelope is in the form of a tubular sleeve and the ends of this envelope are fixed by gluing to the external ends of the

armature tube.

  In use, there is a peeling effect at the level of the attachment of the envelope to the tube, in fact during inflation, the forces are exerted on axes substantially perpendicular to the generatrices of the tube and therefore tend to

  gradually tear off the bond formed by the layer of glue.

  To limit this effect, we complete the bonding with a strapping but the results

remain insufficient.

  Another system is known which consists in fixing on the external face of the tube.

  no longer a tubular sleeve but a pocket like a wheel inner tube.

  The fixing of this closed envelope is done at the center of the external face of the tube so as to limit the stresses exerted during the

inflations / deflations.

  Due to this fixing at a central point of the reinforcement, there is a

  "tracking" effect linked to back pressure.

  This effect results in the air chamber taking off.

  The invention aims to propose a new solution.

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  To this end, the invention relates to a device of the aforementioned type comprising: - a frame constituted by a tube inside which is fixed, at a distance from the ends, a flange closing the inside of the tube and - fixed on this tube, an elastic flexible envelope in the form of a sleeve delimiting with the tube an inflatable pocket, this device being characterized in that the ends of the envelope are fixed on

  the internal face of the tube forming the frame.

  The invention also relates to the method of using the device.

  The invention will be better understood with the aid of the description below made by way of

  of nonlimiting example with reference to the attached drawing which schematically represents: - Figure 1: a section of an inflatable device according to the invention, - Figure 2: an inflatable device used as a shutter, - Figure 3: a device used as a piston,

  - Figure 4: a device used as a pressure accumulator.

  Referring to the drawing, we see an inflatable device 1 intended to be

  introduced, for example, into a pipeline.

  Conventionally, this device comprises: - a frame 2 constituted by a tube 2A inside which is fixed, at a distance from the ends, a flange 2B closing the inside of the tube and - fixed on this tube, a flexible envelope 3 made of sleeve shape

  delimiting with the tube an inflatable pocket 100.

  According to a characteristic of this device, the ends 3A of the envelope are fixed on the internal face 2C of the tube forming the frame and in particular on the

internal ends of said tube.

  Advantageously, the developed length of the sleeve 3, in the neutral position, that is to say not inflated, is greater than the length measured between the two extreme points o this sleeve is fixed so that after fixing said ends of the sleeve to the inside of the tube forming the frame, the length L of the external face of the

  sleeve is greater than length 1 of the armature tube.

  The frame can thus move, along the longitudinal axis of the frame, according to

  a stroke which depends on the difference in length specified above.

  More precisely, the length between the two end points is equal to the distance between each end point and the edge of the sleeve closest to this

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  extreme point to which are added twice the thickness of the sleeve and to which is added

  also the external length of the sleeve.

  The pocket therefore protrudes from the two ends of the tube, if the travel is distributed on either side, or only exceeds on one side, if the mounting is a little different. The advantage of this solution results from the disappearance of the peeling effect while

  by being fixed in two separate areas.

  Indeed, the forces exerted locally in the zone of attachment to the tubes are forces parallel to the generator of the tubular envelope of

1 0 the armature.

  Another advantage of this solution is to allow the device to be able to

  make it work like a piston.

  To this end: - the frame 2 is fitted, for example one of the faces of the flange, with an axial rod 6 projecting relative to the size of the device for transmitting the movement of the piston to a distant load, - the piston is placed in a sleeve 7 closed at one end forming, with the rear of the piston a chamber 8 of variable volume, - the bag 100 is inflated so as to press the external face of the sleeve on the internal face of the closed sleeve thus creating a plug or obturator and - for the displacement of the piston, air under pressure is injected into the chamber 8 of variable volume so that, under the action of the pressure, the armature of the piston moves on a stroke equal to the free part of the pocket exceeding

the armature (Figure 3).

  Given the cross section of the piston, a large force can be obtained.

  For example, when the device has the following characteristics: - outside diameter equal to one hundred and eighty millimeters, - end zone or stroke equal to one hundred millimeters, the device is inflated to eighty bars in a pipe of diameter two

hundred millimeters.

  A film of air or liquid at eighty bars of pressure of thickness, ten millimeters on the periphery of the metal frame is therefore created to thus achieve

sealing by obturation.

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  On the other hand, as there is no longer any mechanical restraint in this equilibrium, when an air or liquid back pressure is injected, the shutter piston will advance by a hundred millimeters until the point when the coated fabric comes block on the

metal part.

  There is therefore rapid displacement at the start and we can then increase in power. In this example with a cross-sectional area of two hundred millimeters equal to three hundred and fourteen cm2 and an inflation pressure of the product of eighty bars, one can have in the variable chamber a back pressure at

  seventy five bars while maintaining the seal.

  We therefore develop a thrust on the piston of:

  314 x 75 bars = 23,550 DAN _ 23 tonnes.

  The inflatable device therefore comprises on one of its end faces a

  rod 6 to transmit its displacement.

  The envelope is a textile sheet coated on either side with an elastomer

  rubber, polyurethane etc ...

  Depending on the resistance required, you can either make straight,

  one or more layers, either by filament winding.

  The confection is always made from elastomer or raw plastomer.

  When the product is made, it can be vulcanized by different methods. These areas being made raw and vulcanized allow to have a

good memory effect.

  In addition, these free zones allow unconstrained removal into the

  composite. As a result, the maximum possible expansion is obtained.

  We can use the system differently (Figure 4) for example, to absorb

  significant pressure variations in a chamber closed by the shutter.

  These variations in pressure could, when they are significant, induce

  sufficient force to slide the shutter along the closed tube.

  To avoid this effect, advantageously, the frame 2 of the inflatable device is provided on its rear face opposite to that subjected to the pressure P of the chamber, with surfaces 10 with a high coefficient of friction carried by rods 11 inclined with respect to the longitudinal axis of the armature, in response to the rearward displacement of the inflatable device, open the ax angle of the rods and

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  thus increasing the application of the friction surfaces on the internal wall of the

folder housing said device.

  It is also possible by using friction surfaces of the aforementioned type but mounted according to a reverse diagram, to advance the device in a pipe and therefore increase the stroke of the piston.

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Claims (6)

  1. Inflatable device comprising: - a frame (2) constituted by a tube (2A) inside which is fixed, at a distance from the ends, a flange (2B) closing the inside of the tube and - fixed on this tube, an elastic flexible envelope (3) in the form of a sleeve delimiting with the tube an inflatable pocket (100), this device being CHARACTERIZED in that the ends (3A) of the envelope are fixed on the internal face (2C) of the tube forming the frame and   in particular on the internal ends of said tube.   2. Device according to claim I characterized in that the length (L) of   the outer face of the sleeve is greater than the length (1) of the armature tube.   3. Device according to claim 1 characterized in that it comprises, on   one of its end faces, a rod (6) for transmitting its displacement.   4. Device according to claim I characterized in that the frame (2) of the inflatable device is provided, on its rear face opposite to that subjected to the pressure (P) acting in a chamber, with surfaces (10) to high coefficient of friction carried by rods (11) inclined with respect to the longitudinal axis of the frame, in response to the rearward displacement of the inflatable device open the angle to the rods and thus increase the application of surfaces of   friction on the inner wall of the shirt housing said device.   5. Method of using the inflatable device according to any one of   Claims 1 to 4, characterized in that:   - the armature (2) is fitted with an axial rod (6) projecting from the bulk of the device for transmitting the movement of the piston to a distant load, - the piston is placed in a closed jacket (7) at one end forming, with the rear of the piston a chamber (8) of variable volume, - the pocket (100) is inflated so as to press the external face of the sleeve on the internal face of the closed liner thus creating a plug or shutter and - for the displacement of the piston, air under pressure is injected into the chamber (8) of variable volume so that, under the action of the pressure, the armature of the piston moves over an equal stroke the free part of the pocket protruding from the frame. 7 2811057   6. Method according to claim 4 characterized in that one equips the frame (2) of the inflatable device, on its rear face opposite to that subjected to the pressure (P) exerted in a chamber, surfaces (10) with a high coefficient of friction carried by rods (11) inclined with respect to the longitudinal axis of the frame, in response to the rearward displacement of the inflatable device open the angle a of the rods and thus increase the application friction surfaces on the wall   internal of the folder housing said device.