WO1989006329A1

WO1989006329A1 - Method and device for excess temperature protection, substantially fire protection of an elongated hollow object conducting an easily inflammable fluid

Info

Publication number: WO1989006329A1
Application number: PCT/NO1989/000005
Authority: WO
Inventors: Clas T. Jacobsen
Original assignee: Norsk Safetech A/S
Priority date: 1988-01-11
Filing date: 1989-01-11
Publication date: 1989-07-13
Also published as: AU2924689A; NO880093D0; NO880093L

Abstract

In connection with fire protection of a longitudinal hollow object conducting an easily inflammable fluid, for example a gasoline pipe, there is according to the invention suggested a combination of materials resulting in a co-operating fire protection and closing of the fluid conducting object, namely in that for the longitudinal hollow object (1) there is used a material which can be compressed upon the influence of moderate pressure, that outside the fluid conducting object (1) there is provided a fire and flame protecting material (2) which under the influence of high temperatures expands at a considerable degree, and that outside the heat expanding fire protecting material (2) there is provided a cover (3) which during a fire controls the expansion of the fire and flame protecting material (2) in the direction towards the inner hollow object (1) for simultaneous fire protection and closing thereof.

Description

METHOD AND DEVICE FOR EXCESS TEMPERATURE PROTECTION, SUBSTANTIALLY FIRE PROTECTION OF AN ELONGATED HOLLOW OBJECT CONDUCTING AN EASILY INFLAMMABLE FLUID.

Field of the invention

The present invention relates generally to excess tempera¬ ture protection of hollow fluid conducting objects.

More specifically, the present invention relates to a method for protecting an elongated hollow object conducting an easily inflammable fluid.

The invention also relates to such fire protected objects.

Prior art

In connection with for example propulsion motors in land- borne, seaborne and airborne vessels, especially vessels carrying gasoline motors, it is of greatest importance that the conduit conducting fuel from the gasoline tank to the motor, is well protected against fire, such that the gaso¬ line supply system remains as a protected system as long as possible after the occurrence of a fire on the vessel.

As requirement to be met by the gasoline pipe or the gasoline house which is to be mounted between the gaso¬ line tank and the gasoline intake of the motor of a car, is that the conduit itself should be bendable or flexible, so that it can easily be mounted along the framework of the vehicle, said conduit also being so effectively in¬ sulated against fire that the driver and possible pass¬ engers will have time to escape from the car in case of fire.

Within the car industry there is worked out certain directions giving an indication of how long a gasoline pipe should resist a fire, but this period of time varies depending of the classification of the vehicle. For example, it is a question of 90 seconds in connection with certain types of vehicles and certain fire approaches whereas for other vehicles the time period could be 5 minutes or longer depending on the possibilities of escape. In airborne planes the possibility of escape is small, and the gasoline pipe should here be safe¬ guarded against fire to a far larger degree than in a land based vessel.

From Norwegian patent application 87.1253 it is known how substantially pipe- or hose-shaped fire protected objects, especially in connection with the supply of fuel from a source to a consumption apparatus, for example a propulsion motor in a vessel, should resist high temperatures and the influence of flames in case of fire in the motor orthe vessel. Further, said Norwegian patent applicaton discloses that the fire protected object should be flexible, or at least bend- able, such that the mounting thereof could take place without bending the conduit by means of special appa¬ ratus. Further, the object is to be manufactured from relatively inexpensive material, for example in running lengths which are to be delivered finished fire pro¬ tected to the place of installation.

In said patent application, there is suggested a solution which is to the fact that around a substantially bend- able plastic pipe there is applied a first layer of an insulation having a relatively low heating conduct¬ ance in the lower temperature range (approximately 100 — 300°C) , and that around the first layer of insulation there is applied a second layer of fire resistant- material which at higher temperatures (approximately 300-900°C) renders a fire resistant effect. In the same application there is given an example that as a first insulation layer there can be used a foamed fire re¬ sistant material which at higher temperatures renders a fire resistant effect, the second layer of the insula¬ tion being a non-foamed layer of fire resistant material which at higher temperatures renders a stable ceramic fire protecting phase. By this combination of foamed and non-foamed fire resistant material, it is achieved that the foamed inner layer constitutes a relatively good heat barrier in the lower temperature range, i.e. in the range of approximately 100-300°C, such that the outer layer then, in case of a fire will be rapidly heated to higher temperatures, i.e. at approximately 300-900°C and higher, for thereby more rapidly to be converted to its cell- shaped ceramic stucture, forming an especially good - fire protecting cover.

Further, in the same application it is disclosed that such a transport conduit for for example fuel, should be mounted inside a rigid shell, and between the layers of insulation and the rigid shell there may be provided a layer of woven glass fiber or fabrics which can burn away under the influence of high temperature, the fabrics at the same time allowing the insulating material to swell to twice its volume during a fire. The insulating material can then reach its fully foamed ceramic con¬ dition without changing the physical outer dimensions of the encapsulated pipe.

Discussion of the invention

The object of the present invention is to give instruc¬ tions for substantially pipe- or hose-shaped fire pro¬ tected objects which not only resolves the problems dis- cussed in the above mentioned patent application, but which also in a simple and safe manner can interrupt the supply of a fluid, for example fuel from a source to a consumption apparatus in case a fire should occur. Generally,the problems are solved by the features stated in patent claims 1 and 6.

In a method for protecting especially an elongated hollow object conducting an easily inflammable fluid, the problem is solved according to the invention in that a) for the elongated hollow object there is used a material which is compressible under the influence of moderate pressure, that b) outside the elongated hollow object there is provided a fire and flame protecting material which ex¬ pands under the influence of abnormally high temperatures., and that c) outside the fire protecting, heat expandable ma- terial there is provided a material which under the in¬ fluence of heat controls the expansion of the fire and flame protecting material in a direction towards the inner hollow object for the closing thereof.

As an elongated hollow object there may appropriately be used a chemicals resistant, compressable plastic materi¬ al, there at the same time being used a fire and flame pro¬ tecting heat expandable material which under the influ- ence of heat expands 1 1/2-4 times on a volume basis, whereas as an outer cover there is used a heat resistant thin metal, for example steel. However, it is to be understood that the swelling material alone can be used as a fluid carrier. Further, it is to be understood that the outer cover can be a pipe-shaped metal, for example a braided bandage being shaped as a winding of metal, ceramic fibres, heat resistant glass etc., having sturdy mechanical properties during fire.

Appropriately, the fire protecting mat-rial may be a so-called plastic/ceramic-material comprising 60-100 parts of weight of a ther o plast, 50-450 parts of weight of aluminum hydroxide and 150-600 parts of weight of calsium carbonate and/or calsium-magnesiu carbonate. The fire resistant material can comprise any type of thermo plast, and can for example comprise ethylen- vinylacetate, and due to production technical reasons there bay be included an elasticizer, a lubricant agent, and a colouring agent and possibly anti- oxidant agents.

Depending on the dimensions to be used, the fire protect¬ ing material can be given different foaming degrees, all of which is adapted to the dimensions of the fluid conducting inner tube and the type of fluid to be transported.

By varying the blowing or foaming agent, the temperature of the initiating swelling may be regulated, for example in the range 150°C-250°C, either by using said aluminum hydroxide as a foaming agent, or by the inclusion/re¬ placement of 5-10 weight % further blowing agent, for example azodicarbonamide ("Genitron") .

Further, the composition of the fire resistant material can be varied within suitable ranges, for example re¬ lating to when the various transfer phases of the ma¬ terial should occur during a fire.

The fire resistant material can for example during the influence of temperatures larger than 90°C be subject¬ ed to softening process, whereas at temperatures be¬ tween for example 200-300°C the material is to be sub¬ jected to a swelling, for example in the range 1 1/2-4 times on a volume basis, and during this swelling phase water should be expelled. The combined expelling of water and the swelling of the material will then at the same time prevent that the fluid in the hollow elongated object obtains such high temperature that a firing of the fluid can take place, whereas this temperature range results in an effective closing of the fluid path as such. In other words, there are given instructions for a self-closing fluid supply pipe, which just in case of a fire will automatically close any further supply of easily inflammable fluid, and thereby prevents the danger of explosion and the risk of further spreading of the fire. At temperatures larger than for example 300°C, the poly¬ mer in the fire resistant material will be subjected to pyrolysis, and in the temperature range 300-600°C organic residual materials will be developed. When the tempera¬ ture of the material exceeds 800-900°C, there will be formed a relatively sturdy cellular ceramic, which will have fire retardent qualities up to 1500°C.

Since there as a possible corrosion protecting thin in¬ ner pipe is used a compressible plastic, this will upon expansion of the outer fire protecting material soften and melt, and the material will at higher temperatures be pressed together and burned away together with the polymer in the fire resistant material, for thereby be¬ ing replaced by a ceramic, swelled non-burnable plug.

Thus, the material will constitute a good thermal con¬ ductor in its original state, whereas at temperatures above 200°C, due to the expelled water, and due to its swelling, will provide a good thermal insulation, whilst at the same time it closes the inner hollow object for further transport of fluid therethrough. In its cellu¬ lar ceramic condition, the material renders good mecha- nical stability, the material also acting as a flame barrier without expelling poisonous smoke or gas.

Thus, the fire resistant material will be converted from having approximately thermo plastic properties at room temperatures, at which the thermal conductivi¬ ty is approximately 0.7w/mc, and to a cellular cera¬ mic having a thermal conductivity of approximately 0,07w/mc.

It is to be understood that the expanding effect of the fire resistant material can also be initiated by an inner raise of temperature, for example from an "over-heated" fluid. This involves a self-closing effect not only in connection with easily inflammable fluid, but also for other types of fluid which shall have its fundamental flowing interrupted at higher temperatur¬ es. This property can be utilized in connection with plants, wherein an elevated temperature of the fluid may represent a pre-warning of fire.

Brief discussion of the drawings

The invention will in the following be further described with reference to the drawings depicting an example of an embodiment of the invention.

Figure 1 illustrates an example of a self-closing device according to the invention, at normal conditions and open inner fluid path.

Figure 2 illustrates the device under the influence of a fire, the inner fluid path being closed.

Figure 3 illustrates the device after the influence of a fire, wherein the inner fluid path is replaced by a ceramic plug.

Description of embodiment In the Figures, especially in Figure 1, the reference numeral 1 designates an inner pipe or a hose manufac¬ tures from plastic, for example nylon. It is to be un¬ derstood that the inner pipe 1 of course can be manu¬ factured from other types of plastic, for example glas fibre reinforced epoxy or polyester. The inner pipe can for example be adapted for the transport of a suitable fluid, for example an easily inflammable fluid, for example a gasoline pipe provided between a source of gasoline and a gasoline driven motor, for example a vessel.

The dimension of the inner, chemicals resistant pipe 1 can for example be 5-6 mm inner diameter, and a wall thickness of 0,5 mm. Around the pipe 1 there is provided a fire and flame protecting material 2, which expands under the influ¬ ence of abnormally high temperatures. The wall thick¬ ness of the fire and flame protecting material can for example be 3 mm, and the material 2 shall in a tempera¬ ture range of 200-300°C be subjected to an expansion leading to a volume expansion of up to 1,5-4 times the original volume.

Outside the fire and flame protecting material 2, there is provided an outer cover 3 of a material hav¬ ing sturdy mechanical properties, for example steel, glass or ceramic having a wall thickness of approxima¬ tely 1 mm. This outer cover 3 is consequently made of a material which under the influence of heat controls the fire and flame protecting material 2 upon the expansion thereof, in a direction towards the inner pipe 1 for the closing of said pipe 1.

It is to be understood that the outer cover 3 which embraces the flame and fire protected inner object can be constructed as various embodiments, such that the total composed structure can have properties ranging from stiffto flexible, all in dependence of the intended field of application of the compound structure.

Further, it is to be understood that the fire and flame protecting material can be of any type, pro¬ vided it at abnormally high temperatures expands in the prescribed manner, i.e. such that it forces the inside pipe to close itself for the through flowing of fluid, as this is sought illustrated in Figure 2.

An example of such a fire and flame protecting materi¬ al can be of the type comprising 60-100 parts of weight of a thermo plastic material, 50-450 parts of weight of aluminum hydroxide and 150-600 parts of weight of calcium carbonate and/or calcium magnesium carbonate. The fire resistant material will then under the influence of temperatures larger than 90°C be subjected to a soften¬ ing process, whereas at temperatures of more than 200°C c it will be subjected to swelling, at the same time as water is repelled. The material is thus a good thermal conductor in its original state, whereas at temperatures above 200°C it will, due to the expelling of water and due to its swelling, constitute a good thermal insula- 0 tion, and at the same time it will force the inside tu- - be to close itself. By a suitable ratio between the components included in this so-called plast/ceramic- material, the swelling in the temperature range of 200- 300°C may be in the range of 1,5-4 on a volume basis. 5

At temperatures larger than 300°C, the polymer will be subjected to pyrolysis, and at higher temperatures or¬ ganic residual materials will be developed, whereas upon exceeding temperatures in the range of 800-900°C 0 there will develop a relatively sturdy cellular cera¬ mic, which will have fire retardent qualities up to 1500°C

After the influence of a fire, the inner pipe 1 will 5 thus not only be closed, but just disappear together with the polymer in the fire resistant material 2, which according to Figure 3 has converted to a ceramic, irreversible plug filling the complete inside of the outer cover 3, and which replaces all of the original 0 inner pipe 1.

Consequently, the present invention gives instructions for fire protection of an elongated hollow object, where¬ in is achived not only a self-closing function alone, 5 but a combined self-closing and fire and flame protect¬ ing effect of the elongated hollow object, which is especially favourable in connection with for example gasoline pipes etc. A self-sealing gasoline pipe which is designed from a pipe- shaped wall material expanding at fire temperatures and being forced to expand inwardly and thereby closing the hole in the pipe, can be constructed in several manners, but must also contain an inner layer of sufficient me¬ chanical strength for forcing the expanding material in¬ wardly and rendering the pipe a good enough axial sturdi- ness when the inner parts are softened. It is often favourable to use a further layer inside the expanding material. This layer must have the necessary resistance to chemicals and have a mechanical sturdyness at moderate temperatures. The material of this inner pipe shall upon expansion in the intermediate layer be so soft that it can be compressed.

Examples of material selection:

Outer layer = Braid of metal or glass fiber. Wall thickness d = approximately 0,2-1mm, for example provided as bandage of glass fiber tape,

Expanding intermediate layer: FAVUSEAL NKX 6277

Thickness 2-4 mm, as regards the inner dimen¬ sion of the hole in the inner pipe

Inner pipe: Nylon

Thickness 0,5-2 mm

Claims

P a t e n t c l a i m s

1. Method for automatic closing of an elongated hollow ob¬ ject at elevated temperature, c h a r a c t e r i z e d i n that there is used an inner elongated object of a material which expands under the influence of abnormally high temperatures, as well as an outer substantially non- expanding material which controls the heat influenced expansion of the inner material for the closing thereof.

2. Method for fire protection of an elongated hollow object conducting easily inflammable fluid, c h a r a c ¬ t e r i z e d i n that a) for the elongated hollow object (1) there is used a material which is compressible under the influ¬ ence of moderate pressure, that b) outside the elongated hollow object there is provided a fire and flame protecting material (2) which expands under the influence of abnormally high tempe¬ ratures, and that c) outside the fire protecting, heat expandable material (2) there is provided a material (3) which un¬ der the influence of heat controls the expansion of the fire and flame protecting material (2) in a direction towards the hollow object (1) for the closing thereof.

3. Method as claimed in claim 1 or 2, c h a r a c t e ¬ r i z e d i n that as expanding material there is used a plastic/ceramic-material which after expansion forms a permanent, irreversible ceramic plug without fluid passage.

4. Method as claimad in claim 2, c h a r a c t e - r i z e d i n that as elongated hollow object (1) there is used a chemicals resistant compressible plastics, and that as fire and flame protecting heat expandable material (2) , there is used a material which upon the influence og heat expands 1,5-4 times on a volume basis.

5. Method as claimed in claim 2 or 4, c h a r c t e - r i z e d i n that there is used an inner hollow object of chemicals resistant, compressible material having an inner diameter 5-6 mm and a wall thickness 0,5 mm, and outside the pipe there is used a flame and fire protecting expandable material having a wall thick¬ ness of approximately 3 mm, and that there is used an outer cover of a substantially non-expandable material, for example metal, ceramic fibre, heat retardent glas, etc. having a wall thickness of approximately 1 mm.

6. Device for automatic closing of an elongated hollow object at elevated temperature, c h a r a c t e r i z e d i n that the object is made of a material which under the influence of abnormally high temperatures expands to a larger degree than the hollow space, as well as an outer substantially non-expanding material which con¬ trols the expansion of the expanding hollow object to self-closing.

7. Device in a fire protected object, substantially an elongated hollow object conducting an easily inflam¬ mable fluid, c h a r a c t e r i z e d b y the following combina¬ tion: a) an elongated hollow object (1) of a material which can be compressed under the influence of moderate pressure, b) a fire and flame protecting material (2) which is provided outside the elongated hollow object (1), and which under the influence of abnormally high temperatures ex¬ pands, and c) an outer material (3) which upon the influence of heat controls the expansion of the fire and flame pro¬ tecting material in a direction towards the inner hollow object (1) for the closing thereof.

8. Device as claimed in claim 6 or 7, c h a r a c t e ¬ r i z e d i n that the device after the influence of abnormally high temperatures comprises an irreversible, permanent ceramic plug with no possibility of fluid pass¬ age.

9. Device as claimed in claim 7, c h a r a c t e ¬ r i z e d i n that the hollow object (2) is a chemi¬ cals resistant, compressible plastic, and that the fire and flame protecting heat expanding material (2) has- a degree of expansion of 1,5-4 times on a volume basis.

10. Device as claimed in claim 7 or 9, c h a r a c t e ¬ r i z e d i n that the inner object has an inner dia¬ meter of size range 5-6 mm and a wall thickness of approxi¬ mately 0,5 mm, that heat expanding material (2) has a wall thickness of approximately 3 mm, and that the outer cover (3) has a wall thickness of approximately 1 mm, the outer material constituting a braided or whole metal cover, which allows for a flexible or sturdy mounting, the inwardly directed control of the expansion of the fire and flame protecting material upon fire being main¬ tained, possibly that the outer material comprises cera¬ ic fibres, heat retardent glass, etc.