GB2135635A - Inflatable device for floatable, pneumatically-stabilised life-saving equipment - Google Patents

Abstract

The device comprises a load-carrying ring (5) and a protective tube (6), wherein, on an inlet valve (4) of the load-carrying ring (5), two filter bags (8, 9) are arranged inside one another, the pore volume of which is 800 to 1300 cm<-2> in the case of a pore radius of 0.07 to 0.15 mm and the specific minimum volume of the inner filter bag (8) is 14 dm<3> and of the outer filter bag (9) is 17 dm<3> per kg of carbon dioxide and between the outer filter bag (9) and the load-carrying ring (5), inside or outside of the protective tube (6), there is provided an insulation layer (7) of cold-resistant insulation material, the breadth of which corresponds at least to the breadth of the outer filter bag (9). The protective tube may extend around corners of the equipment and have diffusers of process textile at the ends. <IMAGE>

Description

SPECIFICATION Inflatable device for flotable, pneumaticallystabilised life-saving equipment The present invention is concerned with an inflatable device for flotable, pneumatically stabilised life-saving equipment.

To a preponderant extent, known life-saving equipment is inflated with a mixture of carbon dioxide and nitrogen. Due to physical reasons, in the case of decompression of the filling medium in the interior of the load-carrying ring, a part of the medium solidifies. The temperature of evaporation of carbon dioxide "snow" is about -760C. No coating materials are known which are able to withstand such a degree of coldness.

Internationally, coating materials are used with a resistance to cold of --60 to 570 C. but which would suffer from cold fracture were they to come into direct contact with carbon dioxide "snow" during the inflation procedure. In order to prevent this direct contact between the coating material of the load-carrying ring and carbon dioxide "snow", as a rule tubular-shaped devices are used which, in the region of the inlet valve, extend on both sides up to about one third of the total length of the load-carrying ring. However, the coating materials used with the mentioned cold resistance of about --600C. have the common disadvantages of a limited stability to ozone, oil, ageing and climate.

Further disadvantages of the known equipment include the possibility of the formation of an uncontrolled formation and deposition of carbon dioxide "snow" in the safety tube, as well as the possibility of the deposition of carbon dioxide "snow" outside the safety tube.

The problem which is to be solved by the present invention consists in the construction of a flexible inflation device for flotable, pneumatically stabilised life-saving equipment which can be folded up and, without considerable additional effort in the inflation procedure, reduces the cold action of carbon dioxide "snow", which forms upon decompression of the gas, upon the coating material so that coating materials can be used which have an increased resistance to ozone, oil, ageing and climate.

Thus, according to the present invention, there is provided an inflatable device for flotable, pneumatically-stabilised life-saving equipment comprising a load-carrying ring and a protective tube, wherein, on an inlet valve for the loadcarrying ring, two filter bags are arranged inside one another, the pore volume of which is 800 to 1300 cm-2 in the case of a pore radius of 0.07 to 0.15 mm., and the specific minimum volume of the inner filter bag is 14 dm3 and the outer filter bag is 1 7 dm3 per kg. of carbon dioxide and between the outer filter bag and the load-carrying ring, inside or outside of the protective tube, there is provided an insulation layer of cold-resistant insulation material, the breadth of which corresponds at least to the breadth of the outer filter bag.

Furthermore, diffusers of porous textile material can be provided on the ends of the protective tube.

The carbon dioxide "snow" forming after passing through the inlet valva accumulates in the inner filter bag and the carbon dioxide is decompressed. Carbon dioxide "snow" is also formed in the inner filter bag due to the further decompression of the carbon dioxide. A decompression outside of the outer filter bag is negligible but, in any case, does not result in the further formation of carbon dioxide "snow".

In order to avoid a direct action upon the loadcarrying ring and especially in the corners and dead ends, the protective tube projects over the corners of the float segment. The diffusers are to effect a gradual transmission of the still cold carbon dioxide to the load-carrying ring. The insulation layer is necessary for the insulation of the load-carrying ring against the localised carbon dioxide with an extremely low temperature in the region of the filter bags.

The inflatable device according to the present invention can be produced with a low expense but reduces the action of the coldness of the filling medium in the inflating procedure to such an extent that, for the load-carrying ring, coating materials can be used which have a reduced but sufficient resistance to cold, the resistance of which to oil, ozone, ageing and climate is, however, greater than that of the coating materials hitherto used.

The present invention will now be described in more detail with reference to the accompanying drawings, in which: Fig. 1 illustrates a load-carrying ring of a lifesaving raft with a protective tube, including diffusers; Fig. 2 is a section along the line A-A in Fig. 1; and Fig. 3 is a section along the line B-B in Fig. 1.

Before making the load-bearing ring 5, all the parts of the flexible inflation device are cut to size, the lateral seams of the filter bags 8 and 9 are closed and diffusers 10 are sewn on to both sides of the protection ring 6. Subsequently and in the sequence, inner filter 8, outer filter 9, protective tube 6 and insulation 7 made of fleece material are placed inside one another in a tubular manner in such a way that the openings for the inlet valve are arranged one above the other. Subsequently, the whole flexible inflation device is closed to form a tube by means of a seam.

The filling amount of carbon dioxide for a loadcarrying tube for 25 persons is 4.59 kg. The seam length a is 610 mm. and the seam length b is 710 mm. (see Fig. 3), whereas the side seam in the case of a load-carrying ring diameter of 355 mm.

has a length of 448 mm. For the filter bags 8 and 9, use is made of a filter cloth with a pore radius of 0.1 to 0.12 mm. and a pore volume of 1050 cm -2 Upon activation of the initiation device 1, the filling medium present in the carbon dioxide high pressure flask 2 flows through the tube 3 and the inlet valve 4 into an anti-icing device provided in the load-carrying ring 5. After passing through the inlet valve 4, due to the sudden expansion, a part of the filling medium is deposited as carbon dioxide "snow" in the inner filter 8. A further part of the filling medium passes through the porous material of the filter 8 and the residual amount of carbon dioxide "snow" possibly still formed collects in the outer filter. The gaseous portion of the filling medium flows through the filters 8 and 9 and is passed on in the coating material tube 6 to the diffuser 1 0. The there-emerging filling medium has reached a temperature of about --500C. so that damage to the coating material can no longer occur.

The concentration of cold, highly localised by the filters 8 and 9, is effectively kept away from the coating material of the load-carrying ring 5 by the tubular shaped insulation layer.

Claims (3)

1. Inflatable device for flotable, pneumaticallystabilised life-saving equipment comprising a load-carrying ring and a protective tube, wherein, on an inlet valve for the load-carrying ring, two filter bags are arranged inside one another, the pore volume of which is 800 to 1300 cm-2 in the case of a pore radius of 0.07 to 0.1 5 mm., and the specific minimum volume of the inner filter bag is 14 dm3 and of the outer filter bag is 17 dm3 per kg. of carbon dioxide and between the outer filter bag and the load-carrying ring, inside or outside of the protective tube, there is provided an insulation layer of cold-resistant insulation material, the breadth of which corresponds at least to the breadth of the outer filter bag.

2. Inflatable device according to claim 1, wherein diffusers of porous textile material are fixed to the ends of the protective tube.

3. Inflatable device according to claim 1, substantially as hereinbefore described and exemplified.