fig1 shows one or more embodiments of a fire - fighting appliance 1 comprising a rotating nozzle unit 2 configured with nozzles 3 extending from a bore formed in the centre portion of the nozzle unit 2 . a tubular element 5 is received in the bore such that an annular space 4 is produced between the tubular element 5 and the bore wall 14 . an axial bearing 7 that is capable of withstanding the separation pressure from the water pressure holds the tubular element 5 in position and closes the annular space 4 such that the water pressure is kept stable within the annular space 4 . a bearing stopper 8 secures the axial bearing 7 in position . a slide bearing 18 positions the tubular element 5 floating in the bore . the tubular element 5 is connected to a source of water . water is passed from the tubular element 5 through openings 20 in the tubular element 5 out into the annular space 4 and to the through nozzles 3 a , 3 b , 3 c from which the water flows in droplet form . the water pressure in the tubular element is used to deliver the water droplets with maximum range . the nozzle area is less than the area of the water supply , which means that any drop in pressure in the water supply will have little impact on the fire - fighting appliance the nozzles 3 are distributed about the exterior of the nozzle unit 2 and two of the sets of nozzles 3 a , 3 c are oriented with their centre axis angled relative to the centre axis of the nozzle unit 2 . when water flows out of the nozzles , this orientation of the nozzles provides a good degree of cover on all sides of the nozzle unit ( forwards , backwards and at the centre portion ), and an efficient dispersion pattern about the surface of the nozzle unit 2 is formed , as shown in fig2 a . in addition , the surfaces are sprayed twice on each revolution of the nozzle unit 2 , as is illustrated in fig2 a , thereby making efficient use of the water . in the one or more embodiments illustrated in the figures , it can be seen that six nozzles are used , each giving a flat disc - shaped dispersion of the water droplets from the individual nozzle . these may be so - called 60 ° nozzles that provide water droplets having a good range . as shown in fig2 a , two nozzles can be positioned at the front portion of the nozzle unit , two at its centre portion and two at its rear portion . this gives a good degree of cover about the exterior surface of the nozzle unit and the water droplets that are passed out of the nozzles form a wall when the nozzle unit is stationary . when the nozzle unit is rotated about the tubular element 5 , the disc - shaped dispersion from the nozzles forms a spherical dispersion pattern and the water droplets are distributed from the nozzle unit in a pulsating action . fig2 b is a front view of the dispersion of the water droplet from the nozzle unit . a motor 25 is connected to the tubular element 5 , for example , in that it is fastened to the tubular element 5 with setting screws . the water pressure in the tubular element 5 is utilised as the driving force for the motor , and an adjusting device in the form of a choke valve 15 is used to regulate the speed of the motor . thus , the motor operates with a conversion ratio between the driving pressure in the water and the output speed of the motor drive shaft 6 . the motor drive shaft 6 is fastened to the nozzle unit 2 , which thus follows the rotational speed of the drive shaft 6 . the nozzle unit 2 is configured with exhaust ducts 11 for discharge of water from the motor . the choke valve 15 is located in the exhaust duct 11 to be able to regulate the size of the passage in the exhaust duct outlet and so determine how much water is to be passed out of the motor 25 . the closing motion of the choke valve 15 into the exhaust duct 11 reduces the speed of the motor 25 and the opening motion of the choke valve out of the exhaust outlet increases the speed of the motor . the choke valve 15 can be screwably secured in the exhaust outlet and is thus configured to be screwed inwards in the exhaust duct in order to make the exhaust outlet smaller , and can be screwed out of the exhaust duct in order to make the exhaust outlet larger . the opening and closing motions are illustrated by double arrow a . seals 10 in the form of o - rings are disposed between an end piece that is fastened to the nozzle unit 2 and the tubular element 5 to prevent water leakage from the bore 4 . the same type of seals 10 are used also to prevent leakage between the exhaust side and the annular space 4 . adjusting devices such as the illustrated choke valve 15 ensure that the rotation of the nozzle unit 2 can be adjusted to a desired speed . use of the motor gives a more stable rotation of the nozzle unit 2 and the rotational speed can be suitably adjusted to a speed at which the water has time to evaporate between the water dosages . the adjusting device can be configured in alternative ways , for example , the speed of rotation of the power unit can be adjusted by regulating the amount of water / water pressure used as input pressure for the power unit . fig1 also shows a plug 30 that is secured between the nozzle unit 2 and the tubular element 5 . the plug 30 transfers any impacts from the nozzle unit 2 to the tubular element . the fire - fighting appliance according to one or more embodiments of the invention thus utilises the water pressure in the tubular element for pressure setting of the water droplets that flow out of the nozzles such that they have kinetic energy with a maximum range , whilst the water pressure is used as a driving force for the motor . the rotation of the nozzle unit 2 is adjusted by regulating the adjusting device ( the choke valve 15 ) such that the water has time to evaporate from a surface of a fire source before the next dosage of water droplets is delivered through the nozzles on the same area of the surface of the fire source in the next round of rotation . the nozzles 3 can be of different design and size in order to vary the size of the droplets that are passed out of the nozzle orifice and the amount of water that is delivered through the nozzles . the number of nozzles can be varied together with their position in the nozzle unit . in the embodiment shown in fig1 and 2 , so - called flat nozzles are used that have an elongate nozzle orifice so that the jet of droplets is thin and broad and exits in a flat fan shape from the individual nozzle orifice . in the example shown in fig1 , the nozzles 3 are shown recessed in the nozzle unit 2 to give better protection against impact etc . during use of the fire - fighting appliance . the shape of the nozzle orifice can be varied and the nozzles can also be provided in the form of replaceable nozzles , for example , in that they are threaded and screwed into the nozzle unit . it may , for example , be desirable to change to nozzles of small size and set the rotational speed of the power unit at a low level if the fire to be extinguished is in a small space . in one or more embodiments , the circumference of the nozzle orifice is configured with a portion where the material is characterised by irregularities . when the water strikes these irregularities , turbulence occurs in the water and water mist is produced along the nozzle wall , whilst larger water droplets are formed which have a longer range in linear flows generated in the centre portion of the nozzle orifice .
a fire - fighting appliance for distributing water droplets includes a rotating nozzle unit configured with nozzles distributed about the periphery of the nozzle unit , and a tubular element that is prepared for connection to a source of water for supply of water to the nozzles . furthermore , the fire - fighting appliance includes a motor that is attached to the tubular element and is driven by the water pressure from the water source . the motor is rotatably connected to the nozzle unit and an adjusting device is provided for controlling the rotational speed of the motor for dispersing water droplets through the nozzles in a pulsating action .