Stock material or miscellaneous articles – Structurally defined web or sheet – Longitudinal or transverse tubular cavity or cell
Reexamination Certificate
1999-11-29
2001-01-16
Copenheaver, Blaine (Department: 1771)
Stock material or miscellaneous articles
Structurally defined web or sheet
Longitudinal or transverse tubular cavity or cell
C428S920000, C428S921000, C428S131000, C428S137000, C428S138000, C442S381000, C442S391000, C442S414000, C062S136000
Reexamination Certificate
active
06174588
ABSTRACT:
The invention relates to a flexible heat and fire protective web of the type presented in the preamble portion of the attached claim
1
.
BACKGROUND
Fire inhibiting structures, in particular fire inhibiting carpets which can be laid over existing conventional oil retaining structures are know. These fire resistant carpets and other fire resistant materials are often made of ceramic fiber materials or woven materials which can withstand high temperature. The materials are often combined with metals which have good heat conducting properties.
A disadvantage concerning materials which contains metals, is that they have a tendency to oxidize/corrode when sea water is present, and their structure changes and weakens when heated.
There are exit barriers which contain both solid and air filled flexible emergency buoy-ancies. Fire restraining barriers containing solid emergency buoyancies can not be coiled in or payed out from a reel. This makes handling difficult and demands a lot of extra work, which constitutes a danger for the barriers. Barriers with flexible floating chambers have little freeboard and spare buoyancy, and therefore there is a chance that they might go down under water during normal tug speed.
The barriers available today are expensive and heavy, and are made up of materials with limited life during a fire, where temperatures in the fire may vary between 800-1300° C. The fire barriers generally have a low buoyancy/weight ratio compared to normal barriers. This causes them to float heavily in the sea, and have poor wave following properties, ans this creates weather-dependent use in open waters. In addition the materials are rigid, and not very flexible, which results in a worsening of the sea-properties.
OBJECT
The object of the invention is to provide a fire and heat protective web which eases or overcomes the disadvantages of known fire protective devices and extinguishing methods.
THE INVENTION
The object is accomplished with a flexible heat and fire projective web according to the characterising portion of claim
1
, and a use of the same according to claim
6
. Further advantageous features are given in the dependent claims.
The invention relates to a fire and heat protective, usually flexible, web, which is characterised by comprising, in a cross section of the web from the heat exposed side:
a selected first support layer consisting of a steam permeable, compact and tear resistant textile web,
one or more liquid conducting layers of a liquid permeable and airy textile material,
a selected second support layer consisting of a steam permeable, compact and tear resistant textile web, and
a conduit mounted at least in the upper part of the fire protective web, for supply of fluid to the fluid conducting weblayer, and to disperse the fluid evenly in the longiudinal extent of the web, whereby the different layers are tightly connected surface-to-surface by means of seams, adhesive means, point fixing or similar.
Although the invention in the following description is, for simplicity, described with special reference to use concerning oil barriers at sea, it should be obvious to a person skilled in the art that the fire protective web can be used for other applications, as will be demonstrated in the following further detailed description.
The fire and heat protective effect resulting from the web according to the invention, arises as a result of a combination between active and passive cooling, in the form of a fluid which flows through the porous and fluid permeable textile material. Before and during use of the web according to the invention, water or another nonflammable fluid is added, through a perforated water tube. Fluids which have boiling points similar to sea water, or are adjusted to the textiles' resistance to heat, can be used.
Temperature control of the web according to the invention, both inside and on it's surfaces, takes place according to the following principle: When a fluid boils, the temperature in the fluid adjusts to it's boiling point, and thereby automatically limits the maximal temperature in the web. The temperature and the evaporation from the surface of the water, stays constant during boiling, and is therefore independent of the temperature of the fire or source of heat. The maximum temperature in the wet fire protective web is therefore 100° C., if the fluid used is water. The minimum amount of water needed to keep the temperature below the boiling temperature, is equal to the amount which evaporates from the web. By increasing the waterflow, further cooling will be achieved.
The term “fluid permeable and airy textile material”, used about the fluid conducting layer, means any textile material, comprising synthetic and/or natural fibres which shows a high capacity to absorb water and a high waterflow capacity, e.g. woven, non-woven and needle cloth of e.g. cotton.
For cloth materials with relatively low inherent strength, e.g. non-woven cloth, it is preferred to combine it with a support layer on one, or preferably both sides. The selected support layer will, in addition to a protective and supporting function, also serve to keep the cooling fluid which flows in the fluid conducting layer, better in its place, and also makes the cooling fluid available to the heat exposed side of the web.
The support layer may comprise materials which correspond to the fluid conducting layer, but it will have a denser structure with higher resistance to tearing, and a lower capacity for flow of fluid. The support layer still shows a capacity to exchange steam between the surroundings and the fluid conducting layer.
In the simplest embodiment, the web includes, an extended horizontal conduit, e.g. in the form of a perforated and flexible tube, at the upper end of the web, to provide an even supply of cooling fluid along substantially the whole length of the web. In cases where the web is very large, or very intense heat exchange is expected, it could be conceivable to provide horizontally conduits, generally parallel with each other, extending downwards in the web, to replace cooling fluid which has evaporated at the upper side of the web.
At the least heat exposed side of the web, may be mounted a block layer with steamblocking and eventually heat leading qualities, e.g. a plastic film like PVC, or flexible metal-foils, e.g. aluminium, so that eventually absorbed heat can be spread out if needed. Such a block layer will prevent eventually evaporation of fluid on the cool side, and also prevent draining of cooling fluid from the fluid conducting layer, and in this way, even more cooling fluid available to the heat exposed side of the web.
A typical thickness of the web according to the invention will be about 2-4 mm, which gives a dry weight of about 300-400 g/m
2
and a wet weight of about 1000-3000 g/m
2
. Thickness, layer construction, and implementation of conduits will of course have to be adjusted to the intended use, and will vary from very simple constructions for some applications, to more complicated constructions for larger applications.
The method for mutual fastening of the different web layers in the web according to the invention, is not essential, but the different layers should be surface-to-surface with each other, to make sure that the whole web gets moistened by the supplied cooling fluid. Consequently, the different web layers can be fastened to each other by e.g. a stable adhesive means, point fixing or by seams. When fastening with seams, the seams must be established generally parallel and vertical considering the web's position during use, so that there will be established vertical channels supplying the flow and spread of water in an even way in and over the web according to the invention. Tests have proven that an advantageous distance between the seams is about 5-10 cm.
The ratio between active and natural flow of water varies according to the choice of textiles and cloth materials. Tests have proven that a web according to the invention with active cooling can receive about 240 times more water per time
Copenheaver Blaine
Nawrocki, Rooney & Sivertson P.A.
Pratt Christopher C.
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