NOZZLE The invention relates to a nozzle comprising a hollow nozzle body rotatably mounted about an admission channel, wherein the nozzle body and the admission channel form an inner chamber and an inlet; which nozzle body is equipped with a plurality of orifices arranged around a periphery, the orifices being arranged in pairs and where the orifices in each pair have their axes closest to each other in a mixing area close to the outer surface of the nozzle body; wherein said inner chamber is in fluid communication with said orifices via a plurality of inner channels in said nozzle body and an outer chamber; wherein the inner channels run through the nozzle body in the plane of rotation of the nozzle at an angle relative to the radius of the nozzle body.

A vast number of spray devices are known.

A host of devices for dispersing water by some form of atomisation are known.

NO-B-176748 describes a nozzle for atomising water for fire-fighting purposes, where a ring of nozzle channels is rotatably mounted on a nozzle holder that is designed to lead water from a housing via a channel and holes, to an annular groove at the inlet of the nozzle channels. The ring is designed to rotate when subjected to reaction force from water flowing through the nozzle channels. In its introductory portion, this patent states that in connection with fire fighting it has"been found to be effective to use dispersed water droplets, almost in the form of a mist which blankets the flames. Water mist can be produced by atomising water through nozzles. Extinguishing a fire using water mist requires less water than extinguishing a fire using a water jet."NO-B-176748 thus represents a very early stage in the development of effective fire-fighting means as it does not involve a water mist but merely a dispersion of water having a particle size of about 300-400 u.

NO-C-178819 describes a high-pressure water spray gun for extinguishing fires, made having a cylindrical body for connection to a water hose and a spray head which is rotatable in the body when subjected to the force of water exiting a pair of jet nozzles around the spray head bore. In each pair, the nozzle axes converge and the nozzles lie closest to one another in a mixing area at or just beyond the outer surface of the bore.

At least one nozzle has a non-radial axis. The spray head may be accommodated in a body and can be moved, against the action of a spring, to an exposed working position when subjected to the force of water pressure.

US 4,393, 941 describes a chimney fire snuffer, comprising a cylindrical nozzle housing having an axially extending admission channel and a plurality of radial nozzles along the admission channel. One end of the nozzle housing is made in the form of a nose and the housing has a substantial wall thickness and consequently a relatively heavy weight, thus enabling it to penetrate through material and reach the fire. However, the device described in this patent has not solved the problem of forming a water mist in the proper sense of the word.

Norwegian Patent Application 20005039 describes a nozzle insert that is characterised in that it is equipped with a plurality of channels (301) which run through the nozzle cover in the plane of rotation of the nozzle insert but at an angle relative to the radius of the nozzle cover, where each channel has a blade-shaped opening into an inner chamber.

On the basis of this prior art, there is proposed according to the invention a nozzle as mentioned above, characterised in that a bladed wheel is arranged as a delimitation between the inner chamber and the inlet, which bladed wheel is arranged to rotate together with the nozzle body and in a plane that is essentially parallel to the plane of rotation of the nozzle and essentially perpendicular to the longitudinal axis of the admission channel.

The same effect is obtained with the blade-shaped channel opening that is known from Norwegian Patent Application 20005039 as with the nozzle device described in NO-C- 178819, but at a considerably lower pressure. The nozzle according to the invention employs the same principles as those described in these documents, namely atomisation of water (NO-C-178819) and increase of pressure (NO 20005039), but exhibits an additional increase in pressure because of the bladed wheel.

Additional features of the invention are set forth in the dependent patent claims.

Embodiments of the invention will now be described in more detail with reference to the drawings, wherein: Figure 1 is a sectional view of a simplified nozzle according to one embodiment of the invention.

Figure 2 shows a section taken along the line A-A in Figure 1. For the purpose of illustration only four channels are shown.

Figure 3 shows a section taken along the line B-B in Figure 1. For the purpose of illustration only two pairs of channels are shown.

Figure 4 shows an embodiment of the bladed wheel according to the invention in different sections.

Figure 5 shows speed and force diagrams for a number of blades, and relevant variables.

Figure 6 (to be omitted) Figure 7 shows increase of pressure as a function of the rotational speed for different amounts of water, at the bladed wheel and in the inner chamber of the nozzle.

Figure 8 shows increase of pressure as a function of the rotational speed for different amounts of water, in the outer chamber of the nozzle.

Figure 9 is an exploded view of a second embodiment of the invention, and illustrates an alternative mounting of the nozzle according to the invention.

A first embodiment of the invention will now be described with particular reference to Figures 1-5. A nozzle comprising a hollow nozzle housing 200 with an insert 400 is rotatably mounted about an admission channel 100 with an inlet 120. The nozzle housing and the insert when assembled are fastened to each other and for all practical purposes can, when in use, be regarded as one nozzle body (200,400). The nozzle body and the admission channel together form an inner chamber 210 and an inlet 120, where both the inner chamber and the inlet are in fluid communication with each other. The nozzle body (in this case, the nozzle housing) is equipped with a plurality of groups of orifices 220,225 arranged around its periphery (two pairs are shown in Fig. 3 for the purpose of illustration), wherein the two orifices in each group have their axes closest to one another in a mixing area close to the outer surface of the nozzle housing. The inner chamber 210 is in fluid communication with said orifices via a plurality of inner channels 420 (four channels are shown in Fig. 2 for the purpose of illustration) in said insert 400 and an outer chamber 250; each individual one of the inner channels 420 runs through the insert in the plane of rotation of the nozzle preferably at an angle 6 in

relation to the radius of the insert and the nozzle housing. The angle 0 (see Fig. 2) may be between 20° and 70°, preferably 50°.

Furthermore, a bladed wheel 300 is provided in the nozzle body, the bladed wheel forming a delimitation between the inner channel 210 and the inlet 120. The bladed wheel 300 is arranged so as to be able to rotate together with the nozzle body, normally mounted therein, and in a plane that is substantially parallel to the plane of rotation of the nozzle body and substantially perpendicular to the longitudinal axis of the admission channel 100.

As can be seen from, for instance, Figures 2 and 5, the bladed wheel 300 comprises a plurality of blades 310 arranged at an angle of a + 0 relative to the plane of rotation of the bladed wheel. The sum of a + 0 is between 20° and 70°, preferably 50°.

The nozzle body also comprises an aperture 410 extending from the inner chamber 210 to the atmosphere, and the longitudinal axis of this aperture is substantially but not necessarily parallel to the axis of rotation of the nozzle. The aperture 410 may be a venturi nozzle.

The same effect is achieved with the blade-shaped channel opening known from Norwegian Patent Application 20005039 as with the nozzle device described in NO-C- 178819, but at a substantially lower pressure. The nozzle according to the invention uses the same principles as described in these documents, namely atomisation of water (NO-C-178819) and increase of pressure (NO 20005039), but exhibits an additional increase of pressure because of the bladed wheel which acts as a pressure barrier between the inner chamber 210 and the inlet 120. Tests have shown that the pressure in the inlet, because of the bladed wheel, is maintained at an almost constant level when the nozzle housing-the insert-the bladed wheel rotate about the admission channel. The rotational moment obtained at the nozzle outlet 220,225 is so great that the bladed wheel can reach a rotational speed of more than 2000 rpm, which in turn gives the desired pressure.

Figure 9 shows a second embodiment of the invention, but the main emphasis is on illustrating how the nozzle according to the invention can be mounted in a extinguisher unit. Figure 9 shows the nozzle housing 6 (corresponding to 200), the admission channel 5 (corresponding to 100), the bladed wheel 7 (corresponding to 300), and the insert 8 (corresponding to 400) with inner channels 8a (corresponding to 420).

The nozzle housing and admission channel can be mounted on one of the plunger halves 4. With the aid of a locking ring 3, spring 11 and a second plunger half 2, the nozzle according to the invention can be moved by water pressure and spring force out of and into a protective housing 1. One of the plunger halves 2 has recesses for 0-rings 9 and 10. The nozzle housing 6 does not show the orifices (corresponding to 220,225). The table below shows the relationship between the two embodiments.

List of components First embodiment Second embodiment 100 5 Admission channel 120 Inlet (li uid supply) 200 6 Nozzle housing 210 Inner chamber 220 Outer radial channel (orifice) 225 Outer diagonal channel (orifice) 250 Outer chamber 300 7 Bladed wheel 310 Blades 400 8 Insert 410 Outer axial aperture 420 8a Inner channel