Technical Field

The invention relates to fire monitors for projecting water long distances for extinguishing fires. In particular, although not exclusively, the invention relates to fire monitors to be mounted on fire-fighting vessels for use in extinguishing fires on oil-rig platforms.

Background Art

Fire monitors currently in use comprise a water conduit,, inlet means connected to the water conduit, and an outlet nozzle connected to the water conduit. Maximum jet throw in fire monitors of this construction is dependent on good inlet conditions to the outlet nozzle and so it is advantageous that flow into the nozzle is free of swirl and of low turbulence level. The water conduit may therefore be provided with flow straightening vanes. However, the inlet means normally comprise bends in two planes in the form of a "ram's horn" inlet. These bends cause swirl which should be dissipated by. the straightening vanes, but in practice insufficient space is available for straightening out the flow after the bends and for reducing turbulence levels. The result is poor performance in terms of jet throw. Difficulty is therefore encountered when attempting to scale up existing designs in order to obtain the long distance water jet throw that has now become necessary.

Disclosure of the Invention It is therefore an object of the present invention to provide a fire monitor capable of much longer water jet throw than hitherto possible.

According to the invention, there is provided a fire monitor, for projecting water, comprising a water conduit having at least two co- axially arranged tubular parts; inlet means and a coaxially extending outl-et nozzle connected to the radially innermost and radially outermost tubular parts of the water conduit; and flow deflectors at

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axially adjacent ends of each radially adjacent pair of coaxially arranged tubular parts providing semi-toroidal, bends to effect reversal of flow so that water flows along radially adjacent tubular parts in opposite directions.

A ire monitor constructed in this manner is capable of providing a high performance jet. If the monitor is to be used with a variable supply it is preferred that the outlet nozzle be adjustable so that its discharge cross-section can be varied to match the number of supply pumps connected to the fire monitor.

In order to improve the performance of the apparatus, guide vanes may be provided between at least two radially adjacent tubular parts and the guide vanes provided in at least the tubular part connected to the outlet nozzle may be adjustable flow controlling vanes. This allows the characteristics of the jet to be controlled by causing atomization or disruption of the jet. The jet can thus be controlled so as to make use of environmental conditions, such as wind, which may require the jet to atomise at a particular height above sea- level so that the wind carries water droplets on to the platform of an oil-rig or on to escaping oil or gas jets. ϋhe resultant control on the size of water droplets which are deposited cn the fire can be used to protect personnel or apparatus in the zone in vshich the water is deposited. Where structures have become heated as a result of fire, it is important to minimise the impact pressure of the water directed on to these structures in order to prevent damage to equipment.

In one simply constructed form of the apparatus according to the invention, the tubular parts of the water conduit are arranged so that the radially innermost tubular part is connected to the outlet nozzle.

Fire monitors according to the invention may also be easily installed by providing the inlet means with swivel mounting means which allow angular movements of the water conduit about at least two

perpendicular axes for adjustment of the axis of the fluid conduit.

To reduce the flow loss in water flowing through the water conduit, the flow deflectors may include a baffle plate extending between each pair of radially adjacent tubular parts, and an adjacent fairing mounted on the radially inner tubular part of each pair of radially adjacent tubular parts along which the water flows in opposite directions, each baffle plate having an outer peripheral portion which is curved so as to cooperate with the adjacent fairing to provide a curved water path. However, even where swirl and turbulence have been eliminated, or at least greatly reduced, there are occasions, as hereinbefore described, when it is desirable to impose a controlled amount of turbulence to the jet. Thus, in addition to the use of adjustable flow controlling vanes, inlet means may be provided for injecting or inducing fluid into the jet. Where this fluid is air, or some other gas, it may be used to disrupt the jet. In other applications the fluid introduced into the jet may be a foaming agent where this is advantageous in particular fire- fighting situations.

To control the flow of water through the outlet nozzle, a centre body may be mounted within the outlet nozzle. This centre body preferably has a longitudinal axis coincident with the longitudinal axis of the water conduit and a cross-section, perpendicular to its longitudinal axis, which varies at different points along its longitudinal axis. In this case, control means may be provided for varying the longitudinal position of the centre body relative to the outlet nozzle.

In one embodiment of the invention, a further conduit is mounted in the innermost tubular part of the water conduit, coaxial with the outlet nozzle; the centre body is hollow and is communicatively connected to the further conduit; a branch pipe extends between the inlet means and the further conduit; and control means are provided for controlling the flow of water through the branch pipe. This water flows out of the centre body into the water flowing through the

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outlet nozzle from the water conduit and therefore modifies this flow. The centre body is preferably formed with at least one outwardly directed aperture and flow of water from each such aperture atomises the water flowing through the outlet nozzle from the water conduit.

Four embodiments of the invention are hereinafter described, by way of example, with reference to the accompanying drawings in which like parts have been assigned the same reference numerals.

Brief Description of the Drawings Figure 1 is an end elevation of a fire monitor according to the invention;

Figure 2 is a sectional plan view of part of the apparatus shown in Figure 1;

Figure 3 is a side elevation of the apparatus shown in Figure 1;

Figure 4 is a schematic sectional side elevation of a second fire monitor embodying the present invention;

Figure 5 is a schematic side elevation of a third fire monitor embodying the invention; and

Figure 6 is an end elevation of part of a still further eπibodiment of the invention, similar to that shown in Figure 5-

Best Modes for Carrying Out the Invention

As shown in Figures 1_ 2 and 3, a fire monitor 1 is provided with inlet means 6 comprising a vertical supply pipe 25 and a swivel 14 for horizontal adjustment of a water-jet issuing from the apparatus. Two branches 24 extend from the pipe 25 into opposite sides of an outer tubular part 4 forming a water conduit 4 and 5 and are provided with swivels 13 for vertical adjustment of the jet issuing from the apparatus.

Water entering the outer tubular part 4 flows axially along the water conduit 4 and 5 past flow straightening vanes 10 and then passes around a semi-toroidal bend into an inner tubular part 5 forming the water conduit 4 and 5 before flowing through outlet nozzle 7- The reversal of flow is effected by flow deflectors comprising a baffle plate 8, which closes the rear end of the outer tubular part 4 _. and fairings 9 which are mounted on the axially adjacent end of the inner tubular part 5 of the water conduit 4 and 5. As shown, the baffle plate 8 has an outer peripheral portion 12 which is curv-ed so as to cooperate with the fairing 9 so as to reduce swirl and turbulence.

In addition to the elongation of the flow path of water through the conduit 4 and 5 by means of the compact arrangement provided by the invention, turbulence and swirl in water fed to the outlet nozzle 7 are reduced to a very low level. Further reduction in swirl and turbulence is also obtained by the use of adjustable vanes 11 which are mounted in the innermost tubular part 5 of the water conduit 4 and 5- The adjustable vanes 11 can also be used to impart a controlled amount of swirl and turbulence to the jet issuing from the outlet nozzle 7 in order to control the characteristics of the jet.

In the fire monitor 2 shown in Figure 4 _S a further conduit 20, which is mounted in the innermost tubular part 5 of the water conduit 4 and 5 and supported at bearing 28 and control station 19, is communicatively connected to a hollow centre body 18 for controlling the size of the flow cross-section of the outlet nozzle 7 •

The further conduit 20 is also connected to the inlet means 6 by means of a branch -pipe 21 which is provided with a control valve 22 for varying the flow of water through outwardly directed outlet openings 23 in the centre body 18 so as to vary the characteristics of the water jet issuing from the outlet nozzle 7.

This flow may also be varied by control means 19 which can be operated to vary the longitudinal position of the centre body 18 relative to the outlet nozzle 7 _. as a result of non-uniform cross-

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section of the centre body 18.

As schematically shown, the fire monitors 1 and 2 may also be provided with additive fluid inlet means 26 for injecting or inducing liquid or gas into the water passing through the water conduit 4 and 5- Depending on the design of the inlet means 26 and its location relative to the nozzle 7. this additive fluid can be used to disrupt the jet.

In the fire monitor 3 shown in Figure 5 _. the vertical supply pipe 25 is connected to a ball-and-socket joint 15 by a flange connection 29 for use in swivelling the apparatus so as to control the direction of the jet issuing from the outlet nozzle 7 •

The fire monitor 3 shown in Figure 5 πiay be modified as shown in Figure 6. Here, the inlet means comprise a vertical supply pipe 25 provided with a swivel 16 for horizontal adjustment of the apparatus about a vertical axis. The pipe 25 has two horizontally extending inlet branches 27 which are provided with swivels 17 to allow the fire monitor to be adjusted about a horizontal axis.