GB2260078A - Apparatus suitable far fighting oil well fires - Google Patents

Abstract

Fire fighting apparatus suitable for extinguishing oil well fires comprises a heat resistant chamber (1) open ended at its intended upper and lower ends, said chamber (1) incorporating a cooling jacket (2) and means for the supply of non-combustible cooling fluid (5) through said jacket. The cooling fluid (5) is adapted to be ejected from spaced nozzles (3) disposed about the interior surface of the chamber (1) and directed generally towards the axis thereof to cool and/or smother combustion in said chamber (1). Chamber (1) may also be adapted to receive a supply of gas e.g. nitrogen, carbon dioxide. <IMAGE>

Description

FIRE FIGHTING APPARATUS.

The present invention relates to a fire fighting apparatus of the type utilised to deal with high temperature chemical fires, of which the most common are oil fires.

The technology for fighting oil fires currently provides a single piece cylinder of a heat resistant material disposed at the end of a gantry, which cylinder is disposed over a flame at a well head, while being subjected to external cooling by one or more cooling jets of water. Often a smothering gas such as nitrogen or carbon dioxide is supplied to the cylinder to deprive the fire of oxygen.

Whereas such an arrangement can be made to work on occasions. there are a number of disadvantages inherent therein. In the first place it is difficult to deliver an adequate supply of cooling water to the exterior of the cylinder, which thus tends to overheat. Further in many instances water is a scarce commodity and the use of the single piece cylinder predicates the wastage of large quantities of water for cooling purposes. Further in exposed sites high winds can deflect the cooling jets of water and make it difficult to cool it evenly, particularly while the cylinder is being moved into position. This problem has been partially addresses in DD-83947 which reveals a single piece chamber for extinguishing oil fires with a side entrance for water.This device is heavy and requires large volumes of water.

Furthermore the effect of extinguishing a fire with an arrangement of the prior art necessarily means that large amounts of oil under pressure flow on to the ground and are not only wasted, but can significantly increase the hazards of re-ignition. This problem has been addressed in US-A-3554290 with oil pollution of the sea-ways in mind. In this disclosure a hood is placed over a marine well head to extinguish an oil fire and to collect the oil. The hood is of a massive construction and of course water supply is not a problem.

In Oil and Gas Journal, 22nd April 1991, volume 33, pages 6 and 7; there is described the concept of placing a large upwardly convergent open topped tube over a source of combustion and collecting any unburied oil from the sides of the tube; the oil being caused to rlm don the sides of the tube in use to a collection point.

Accordingly, it is an object to the present invention to provide means whereby cooling liquid such as water is retained in and cools a combustion chamber and is directed towards the point of combustion.

It is a second object of the present invention to direct a high pressure supply of cooling liquid towards the point of combustion from all directions without wasting water.

It is a third object of the present invention to provide a light heat-resistant structure by incorporating a cooling jacket with the simultaneous cooling of the point of combustion by means of high pressure cooling liquid such as water.

It is a fourth object of the present invention to provide a fire fighting apparatus comprising a combustion chamber including means for the collection of waste oil products and means for transporting them to storage.

The foregoing objects of the invention may be achieved by arranging that a cooling fluid such as water is ejected from spaced nozzles disposed about a cooling jacket in a direction and at a pressure such that the cooling fluid is directed towards the point of a combustion in the chamber, thereby to cool and/or smother the combustion in said chamber.

Accordingly the present invention provides a fire fighting apparatus which comprises a heat resistant chamber open ended at its intended upper and lower ends, said chamber incorporating means for the supply of a non-combustible cooling fluid to said jacket; characterised in that the cooling fluid passes through a cooling jacket before being ejected from spaced nozzles disposed about the interior surface of the chamber and directed generally towards the axis thereof; thereby to cool and/or smother combustion in said chamber.The nozzles may be spaced about the chamber at or adjacent the upper edge thereof and be so constructed and arranged that the direction of ejection of the cooling fluid from the nozzles is generally perpendicular to the axis of the chamber, + 45U. In another form of the invention the angle of ejection of the cooling fluid of at least some of the nozzles is such as to play downwardly on to the interior face of the chamber, or directly towards the seat of combustion.

Generally the cooling fluid supplied to the cooling jacket is water, optionally with other additives such as surfactants or boiling point enhancers. Preferably the flow of the cooling fluid in the cooling jacket is upwards and at a high pressure, for example 10.5 to 21 kg/cm (150 - 300 psi).

In a further form of the apparatus the chamber is adapted to receive a supply of a non-combustible oxygen supplanting gas; for example, nitrogen or carbon dioxide. This is generally supplied to the inferior portion of the chamber in use.

In one form of the present invention the chamber may be a right cylinder, but in the second form the chamber is generally frusto-conical. The lower edge of the chamber may provided with one or more radially disposed apertures so that with the chamber resting upon the ground, about a well head for example, unburned chemical feed stocks such as oil will flow out of the radial aperture from the chamber for collection, or to waste.

The chamber may be provided, at a position inferior to said nozzles, with a downwardly directed generally frusto-conically shaped element adapted to urge sunburned liquids towards the interior walls of the chamber. Said frusto-conically shaped element may be entire, or may be provided with a plurality of small spaced apertures to allow gas to flow therethrough. Intermediate the upper and lower end of the chamber may be located an annular channel section associated with means for transferring a collected liquid to the exterior. Alternatively a baffle construction may be utilised.

It will be appreciated that a chamber, having been instrumental in extinguishing a fire in accordance with the present invention, may be left in sitar to collect oil from a well head. In this connection it will be noted that with the nozzles correctly orientated to supply a stream of high pressure cooling liquid downwardly and inwardly into the chamber, and with the frustocone in site, a chemical or oil fire can be rapidly contained. With the high pressure liquid flow continuing, the liquid from the spaced nozzles will tend to force the oil or other chemical feed stock rising through the chamber towards the interior walls thereof. whereupon it will cool as it flows into the annular channel for disposal.

In a further aspect of the invention there is provided a method of fire fighting which method comprises locating a heat resistant chamber over a point of combustion and cooling the same as hereinbefore set forth;; characterised by providing a cooling jacket to said chamber, passing cooling fluid through said jacket, and subsequently directing said cooling fluid generally towards the axis of the chamber thereby to cool and/or smother combustion in said chamber. Preferably the flow of cooling fluid in the jacket and the flow of combustion gases into the chamber are co-current. The cooling fluid, preferably water with or without additives. is preferably ejected from the upper edge of the chamber at an angle perpendicular to the angle axis of the chamber + 45".

The foregoing description has been directed mainly to an apparatus for fighting oil fires. It will be appreciated that any chemical feed stock from which a high temperature flame emanates from a defined source can be extinguished using the present apparatus. Further within the bocly of the specification reference has been made to a cylinder. This is a term of art utilised to define a generally tube shaped solid material with heat resistant qualities. Plainly such a "cylinder" may have a shape other than that of right a cylinder, including non-regular tubular or channel shaped sections.

The present invention will now be described by way of illustration only, with reference to the accompanying drawings.

Figure 1 shows a vertical elevation in part cross-section of a first embodiment: Figure 2 shows a vertical elevation in part cross-section of a second embodiment, Figure 3 shows a vertical elevation in part cross-section of a third embodiment, and Figure 3.1 and 3.2. each show a vertical elevation in cross-section of a upper part of the third embodiment with baffles replacing the cone.

With reference specifically to Figure 1 there is provided, generally in the form of a right cylinder, a chamber (1) formed of stainless steel or other material having a softening point above 1500 C. The chamber (1) is provided on its interior face with a cooling jacket (2), the gap between the exterior wall of the chamber and the interior wall of the cooling jacket being about 20 mm.

Spaced regularly about the uppermost face of the chamber (1), and operatively connected to the cooling jacket (2) are a plurality of regularly spaced nozzles (3).

The nozzles (3) are adapted to be adjustable to provide a jet of high pressure cooling liquid directed inwardly and generally towards the axis of the chamber (1).

The chamber (1) is supported by means of lugs (7) by a gantry (6) in accordance with arrangements known in the art.

Cooling liquid, which is generally water with additives such as a surfactant or other material adapted to increase its boiling point and to reduce fluid friction with metal surfaces, is supplied to the lower portion of the cooling jacket (2) by means of a cooling water input line (4). Similarly a gas input line (5) supplies carbon dioxide or any other inert gas to the interior of the chamber (1) in known fashion. In use the gantry (6) is operated so as to position the chamber (1) over the a burning well head while cooling water is supplied from pipe (4) to the jacket (2) to reduce the heating effect in so far as it is possible.Cooling water flows out of the nozzles (3) towards the point of combustion. and hence by adjusting the relative height of the chamber (1) the flame may be extinguished by application thereto of the cooling water from the nozzles (3).

With the device in sitit carbon dioxide is pumped along input line (5) so as to further reduce the oxygen content within the chamber (1) thereby to assist in smothering combustion. The device is kept ilz situ for a period after the combustion has been extinguished in order to cool the damaged well head sufficiently to prevent re-ignition; the well head may then be capped.

With reference to Figure 2 the alrrtngemeat of Figure 1 is repeated with the exception that chamber (1) and the cooling jacket (2) are extended and formed as a frustocone rather than a right cylinder. The intended lower edge of the chamber (1) is provided with a radial outlet (S) for oil or other waste products.

It follows that the gantry (6) may be utilised to place the chamber over a burning well head when this is on a suitable surface such as the p-ound. The effect of this is that despite the aperture (8), the amount of oxygen reaching the interior of the chamber is reduced. The reduced diameter of the upper edge of the chamber (1) further reduces oxygen availability. The nozzles work in exactly the same way as described in Figure 1. Combustion may thus be extinguished by operating analogously.

Subsequently, the chamber (1) is left in site on the go'wound over the well head until such time as the well head has sufficiently cooled to prevent re-ignitioll: the device will not fill with oil under pressure from the well head because of the outlet (8).

With reference to Figure 3 the arrangement of Figure 1 is substantially repeated with the exception that the length of the chamber, in this case a right cylinder.

is extended somewhat and adapted to accommodate an intermediate annular channel (9) disposed generally in the lower portion of the chamber (1) and fixed to the interior wall thereof. It will be appreciated that oil running down the internal wall of the chamber (1) will form as a reservoir in the intermediate annular channel from which it may be pumped via exit port (10) and pUlllp and line assembly (11) to a storage facility.

The annular channel (9) forms at its central portion a flame annulus (12) which is adapted to contain the flame emanating from the well-head. Disposed above the intermediate annular channel, and in opposition thereto below the ring of nozzles (3), is an annular cone support (13) extending perpendicular to the axis of the clamber (1) and inwardly of its interior face. Depending from the inner periphery of the cone support (13) is a downwardly and inwardly directed frusto cone portion (14) to define an anangement adapted to catch as much unburned oil and combustion products as possible while still allowing the flame to pass therethrough without significant impendance.

In an alternative embodiment the arrangement of Figure 3 maybe used without the cone portion (14) or the annulas support (13) if desired.

In Figures 3.1 and 3.2 there are shown two alternative forms of the invention.

In Figure 3.1 a single baffle (15) is supported at an angle to the horizontal accross the chamber (1) by means of support (13). The baffle is not entire so that it deflects unburnt oil, but allows combustion products to escape.

Figure 3.2 shows a double baffle system with baffles (16) and (17) disposed across the chamber (1) and generally downwardly directed, preferably at different angles to allow a generally centrally disposed aperture (1) for combustion products.

Again the purpose of these baffles is to direct oil outwardly towards the wall of the chamber while allowing combustion products to escape.

In use, at least some of the nozzles (3) are directed downwardly and inwardly preferably so as to converge at the point of combustion of the oil at the wellhead. Simultaneously carbon dioxide is pumped via inlet (5)into the portion of the chamber (1) below the intermediate annular channel (9), and if desired intermediate the annular channel (9) and the cone (14) as well. The effect of the high pressure cooling liquid from the nozzles (3) is first to extinguish combustion and subsequently to urge the unburied oil to the interior wall of the chamber; whereupon said oil flows down into the annular channel (9) and to the exterior via port (10) and pump (11).

It will be appreciated that height, width, and diameter and the size and shape of the cooling jacket may all be adjusted to suit individual requirements.

By utilization of an apparatus in accordance to the present invention it has been found that oil fires particularly can be extinguished with relative facility and the waste oil remaining unburnt after the fire has been extinguished can be collected and sent to storage.

The invention therefore provides a method of fire fighting as hereinbefore set forth and an apparatus for effecting the same. The invention also provides a method of fire fighting which incorporates a method for collecting unburned oil or other chemical feedstock utilizing the same apparatus.

Claims (20)

1. A fire fighting apparatus which comprises a heat resistant chamber open ended at its intended upper and lower ends, said chamber incorporating a cooling jacket and means for the supply of non-combustible cooling fluid through said jacket, characterised in that the cooling fluid is adapted to be ejected from spaced nozzles disposed about the interior surface of the chamber and directed generally towards the axis thereof thereby to cool and/or smootlle combustion in said chamber.

2. An apparatus according to Claim 1 characterised in that the nozzles are spaced about the chamber at or adjacent the upper edge thereof, and that the direction of ejection of at least some of the nozzles is perpendicular to the axis of the chamber + 45".

3. An apparatus according to either of Claims 1 or 2 characterised in that the fluid for the cooling jacket comprises water, and that the flow of said water in the cooling jacket is upward at high pressure.

4. An apparatus according to any proceeding Claim characterised in that the chamber is also adapted to receive a supply of a non-combustible oxygen supplanting gas.

5. An apparatus according to any of Claims 1 to 4 characterised in tliat the chamber is a right cylinder.

6. An apparatus according to any of Claims 1 to 4 characterised in that the chamber is generally frusto-conical.

7. An apparatus according to any preceding Claim characterised in that the lower edge of the chamber is provided with a radially disposed aperture.

8. An apparatus according to any of Claims 1 to 6 characterised in that the chamber is provided at a position inferior to the nozzles with a downwardly directed generally frusto-conical element adapted in use to urge an unburnt liquid towards the interior walls of the chamber.

9. An apparatus according to any of Claims 1 to 6 characterized in that the chamber is provided at a position inferior to the nozzles with at least one downwardly directed baffle adapted in use to urge unburnt liquid toward tulle interior wall of the chamber.

10. An apparatus according to Claim 8 or 9 characterised in that intermediate the upper and lower end of the chamber is located an annular channel section, said annular channel being associated with means for transferring said collected liquid to the exterior.

11. An apparatus according to any of Claims 4 to 10 characterised in that it is adapted to be utilised on oil fires; wherein the cooling fluid is water with additives adapted to increase the boiling point thereof; and that the combustible gas is selected from carbon dioxide and nitrogen.

12. An apparatus according to any of Claims 1 - 11 characterised in that at least some of the nozzles are adapted to direct cooling liquid against the interior wall of the chamber in use.

13. A method of fire fighting which comprises locating a heat resistant chamber over a point of combustion, and cooling said chamber; characterised by the provision of a cooling jacket to said chamber, passing cooling fluid through said jacket, and subsequently directing said cooling fluid generally towards the axis of the chamber thereby to cool and/or smother combustion in said chamber.

14. A method according to Claim 13 characterised in that the flow of cooling fluid in said jacket and the flow of combustion gasses in the chamber are co-current.

15. A method according to either of Claims 13 or 14 characterised in that the cooling fluid is ejected from said cooling jacket at a pressure of between 10 and 20 Kg/cm2 at or adjacent the upper edge of the chamber, and at an angle perpendicular to the axis of the chamber + 45'.

16. A method according to Claim 15 characterised in that a portion of the cooling fluid is also downwardly directed against the internal face of the chamber to assist in washing sunburned feedstock therefrom.

17. A method according to any of Claims 13 to 16 including the further step of collecting sunburned liquid feedstock in a receiver channel within the chamber and transporting it to the exterior.

18. A method according to any of Claims 13 to 17 utilized to fight oil fires and chalacterised in that the cooling fluid is a liquid including water and in that the secondary gas is applied to the chamber to supplant oxygen.

19. An apparatus substantially as hereinbefore set forth, with reference to and/or as illustrated in, Figures 1 to 3.2 of the accompanying drawings.

20. A method substantially as hereinbefore set forth, with reference to and/or as illustrated in, Figures 1 to 3.2 of the accompanying drawings.