The present invention relates to a spray head having a number of nozzles for spraying liquid fog, said nozzles being positioned in respective housings.

Violent fires, such as oil fires, and, alternatively, relatively small fires, which often are smouldering fires, may occur in, for instance, the engine rooms of ships. To extinguish a violent fire, for example, in a diesel engine, a liquid fog jet with great penetration, i.e. with an ability to penetrate through rising hot air and flue gases down to the actual seat of fire, is at least initially required. The site of a possible violent fire can normally be predicted with a high probability and the required spray heads can be placed at suitable places.

However, a small possibly smouldering fire may break out almost anywhere and the most reliable way to extinguish such a fire is to flood the entire space in question with fine liquid fog, so-called "total flooding".

The object of the invention is to provide for a new spray head which can be used to extinguish both large, violent fires and small fires.

The spray head according to the invention is mainly characterized in that it has at least one nozzle having a relatively large nozzle opening in order to produce a powerful liquid fog jet at a high propellant fluid pressure, several nozzles having a respective considerably smaller nozzle opening in order to produce a fine liquid fog jet, and that said at least one nozzle having a relatively large nozzle opening is arranged to be closed by a spindle loaded with a spring in the direction of the fluid

pressure at a fluid pressure which can be determined in advance.

There are preferably several nozzles having a respective relatively large nozzle opening, for instance three such nozzles located centrally in the spray head, whereas the nozzles having a respective considerably smaller nozzle opening, for instance nine in number, are suitably arranged in the periphery in a circle.

The nozzles having a respective relatively large nozzle opening can be arranged to close at a fluid pressure of, for instance, 70 bar. Consequently, at a lower fluid pressure, the spray head sprays liquid fog only via the nozzles having a respective considerably smaller nozzle opening, whereby additional gas can very well be mixed into the liquid fog, for example in accordance with the disclosure of Finnish Patent Applica¬ tion 941,738 or 941,975.

The invention will be described in greater detail in the following with reference to an embodiment illu- strated in the enclosed drawing.

Figure 1 shows a longitudinal section of a spray head.

Figure 2 shows on a larger scale a longitudinal section of a nozzle, in the open state, having a relative- ly large nozzle opening.

Figure 3 shows, like Figure 2, a nozzle, in the closed state, having a relatively large nozzle opening.

The spray head in Figure 1 comprises a housing provided with a central inlet channel 2 for extinguishing liquid. The inlet channel 2 is via branches 3 in contact with nine nozzles 4 arranged in the periphery in a circle in the enclosed drawing, said nozzles having a housing and a relatively small nozzle opening, for instance 0.5 mm in diameter. A further branch 6 extends from three of the branches 3 to in total three nozzles 7 centrally arranged

in the enclosed drawing, said nozzles having a housing and a relatively large nozzle opening 8, for instance 1.5 mm in diameter.

In preferably each branch 6, i.e. inlet 6, to the nozzles 7 having a relatively large nozzle opening 8, such a spindle is fixed that has a sleeve-like part 9, open at the end adjacent to the inlet 6 and preferably in tightly sliding contact with the inlet 6 wall. Said spindle comprises at least one flow port 10 in the sleeve wall, and a head 11, against which a spring 12 presses or abuts, one end of the spring resting via a filter 13 against the housing of the nozzle 7.

In Figure 2, the fluid pressure in the inlet 6 is so high, for example 200-300 bar, that the spindle with its head 11 compresses the spring 12, causing the shoulder 16 of the head 11 to detach from a corresponding contact surface 17 in the housing of the spray head 1 and extin¬ guishing liquid to flow out via the openings 10, via a circular room 18 between the spindle head 11 and the hous- ing 1, through the filter 13 and between (along) the coils of a helical spring 15 placed around a pin 14 in a helical passage 19 and out through the nozzle opening 8.

In Figure 3, the fluid pressure in the inlet 6 has decreased, for instance to 70 bar, whereby the spring 12 has overcome the fluid pressure and pressed the spindle head 11 tightly against the housing 1 (surfaces 16 and 17), which causes the liquid passage from the channel 6 to the nozzle opening 8 to be closed, liquid flowing only to the nozzles 4 arranged at the periphery in a circle. The nozzles having a respective relatively large nozzle opening can be arranged to close after the fluid pressure has decreased to a given value within the range of, for example, 50 to 90 bar.