Abstract:
The invention relates to a spray head comprising a holder body ( 3 ′), at least one nozzle ( 2′, 2   c ′) and a cover ( 13 ′) which in a protective position is arranged in front of said nozzle when the spray head is in an inactive mode, the spray head comprising means ( 6′, 10 ′) for providing a displacement of the cover from the protective position to a free position in which the cover keeps clear of the nozzle so that it can spray extinguishing medium when the spray head is in an active mode, the holder body comprising an inlet ( 5 ′) for incoming extinguishing medium. In order for the spray head to be able to be installed and operate in surroundings where it is exposed to dirt and impurities for long periods of time, the spray head is characterized in that the means for providing the displacement of the cover ( 13 ′) comprises a device ( 6 ′) which is displaceable with respect to the spray heat and which by means of fluid pressure is arranged to exert a force on a locking device ( 14′, 17 ′) in the cover ( 13 ′) to make the locking device open and consequently displace the cover to said free position.

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to a spray head comprising a holder body, at least one nozzle and a cover which in a protective position is arranged in front of said nozzle when the spray head is in an inactive mode, the spray head comprising means for providing a displacement of the cover from the protective position to a free position in which the cover keeps clear of the nozzle so that it can spray extinguishing medium when the spray head is in an active mode, the holder body comprising an inlet for incoming extinguishing medium. 
     Such spray heads are known for example from U.S. Pat. No. 4,014,388 and U.S. Pat. No. 4,880,063. The cover serves to provide an aesthetically appealing sprinkler of a type which in an inactive mode is concealed in a ceiling, for example. In such concealed sprinklers, the cover mainly serves to keep a deflect plate in a retracted position for aesthetic reasons. 
     In these known sprinklers, the cover falls downwards when the material holding the cover in position melts as it is exposed to heat. Once the cover falls, the heat-activated release means of the sprinkler immediately comes into contact with heat, releasing the sprinkler. 
     In certain surroundings, the spray heads are exposed to dust, deposits and other material that can prevent the supply of extinguishing medium in a fire by clogging the spray head nozzles. Spray heads and sprinklers are installed in order that they operate, when required, up to several years after installation and, consequently, they are naturally exposed to dirt in certain surroundings. A cover in the form of a plate (cf. U.S. Pat. No. 4,014,388 and U.S. Pat. No. 4,880,063, for example) installed in front of the nozzles mainly provides mechanical protection against impacts. Some protection against dirt may be provided, but these known sprinklers are mounted in surroundings where dirt is no problem. In certain surroundings, the amount of dirt and impurities is so high that no spray heads at all have been mounted, the assumption being that they would not operate reliably. This is the case although spray heads are most desirable in some of these applications. As examples may be mentioned open rail cars transporting expensive equipment that may catch fire, for example vehicles. Other applications include painters&#39; workshops and steel plants. 
     Mechanical loads can also make the nozzles of a spray head inoperative. Such mechanical loads may be created by impacts caused by trucks, lorries etc. in industrial halls, garages and on car decks onboard ferries. 
     BRIEF DESCRIPTION OF THE INVENTION 
     The object and idea of the invention is to provide a spray head without said drawbacks and which, therefore, can be used in difficult, typically dirty, surroundings and which has a simple structure. The structure of the sprinkler is typically such that nozzles and other components are simultaneously protected from dirt, dust, deposits and other material which may prevent the spray head from supplying extinguishing medium. 
     For the above purposes, the present invention provides a spray head comprising a holder body, at least one nozzle and a cover which in a protective position is arranged in front of said nozzle when the spray head is in an inactive mode, the spray head comprising means for providing a displacement of the cover from the protective position to a free position in which the cover keeps clear of the nozzle so that it can spray extinguishing medium when the spray head is in an active mode, the holder body comprising an inlet for incoming extinguishing medium, wherein the means for providing the displacement of the cover comprises a device which is displaceable with respect to the spray heat and which is arranged by means of fluid pressure to exert a force on a locking device in the cover to make the locking device open and consequently displace the cover to said free position. 
     In a structurally simple embodiment of the invention, the cover is arranged to place the spray head in the active mode during the displacement. 
     The displaceable device preferably has a projection area which is arranged to exert the force on the locking device under fluid pressure in a pressure chamber. 
     The displaceable device preferably comprises a sleeve-like part which together with the holder body defines the pressure chamber, the sleeve-like part comprising the projection area in the area of the pressure chamber. Such a structure is simple and operatively reliable. 
     The pressure chamber can be in fluid communication with the inlet via a passage when the spray head is in the inactive mode. This being the case, an extinguishing medium pressure in the inlet provides said force against the locking device. This provides an extremely simple way for the spray head to shift to the active mode. Alternatively, according to an extremely advantageous embodiment of the invention, the pressure chamber is in connection with a control line via a passage, so that a fluid pressure in the control line is arranged to provide said force against the locking device. This embodiment is particularly suitable for so-called wet pipe systems in which the pipes are filled with pressurized extinguishing medium, and an extinguishing medium pressure acts in the inlet to the spray head without this pressure as such, i.e. without the pressure in the control line, being able to make the spray heat to shift to the active mode in which it sprays extinguishing medium. 
     When a sleeve-like part is used, it is preferably composed of a cylindrical part comprising a first cylindrical inner surface and a second cylindrical inner surface in the area of the pressure chamber, the first cylindrical inner surface having a larger diameter than the second cylindrical inner surface so that a shoulder forms between said cylindrical inner surfaces, the shoulder defining said projection area as a ring area. Such a cylindrical part is easy to make and easy to attach to the holder body. Furthermore, in this case the sleeve-like part is preferably sealed against the holder part by a first ring seal positioned in the first cylindrical inner surface and a second ring seal positioned in the second cylindrical inner surface in such a manner that the fluid supplied to the pressure chamber cannot flow out of the pressure chamber. 
     When a sleeve-like part is used, it preferably comprises a third cylindrical inner surface arranged to bear tightly against a third ring seal when the sprinkler is displaced to the active mode. This provides extra sealing against leakage; both the first and third ring seals seal against leakage. 
     The cover is preferably fluid-tight and hermetically arranged against the spray head by means of a seal which is preferably composed of the third ring seal. This provides the spray head with effective protection against dirt. The cover preferably comprises a cylindrical groove for the third ring seal, which groove and ring seal hold the cover in place in said protective position. 
     The preferred embodiments of the invention are disclosed in the attached claims  2  to  26 . 
     One of the major advantages of the spray head is that it can be used in applications in which spray heads have not been considered to operate reliably up to now, and have therefore never been installed. In such applications the spray head of the invention is able to operate without problems. The shift of the spray head from the inactive to active mode can be achieved manually or by means of different detection systems very rapidly in different ways by means of fluid pressure. The fluid pressure can be produced for example manually by starting a pump which supplies fluid to the spray head or manually by opening a valve for supplying fluid to the spray head. The fluid pressure can be provided by means of fire detectors (e.g. smoke, heat or flame detectors) which give a signal to activate the equipment. The signal can be given to a pump which starts to supply extinguishing medium to the spray head, or the detector can be arranged to give a signal to a valve which opens so as to supply fluid (extinguishing medium, for example) to the spray head. The sensitive components of the spray head, such as nozzles, are protected against dirt, deposits and mechanical impacts. The structure of the spray head is very simple. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the following the invention will be described with reference to the attached drawing, in which 
     FIG. 1 shows the spray head of the invention in a first, inactive mode, 
     FIG. 2 shows the spray head of FIG. 1 in an intermediate mode, 
     FIG. 3 shows the spray head of FIG. 1 and 2 in an active mode, 
     FIG. 4 shows another, extremely recommendable, embodiment of the spray head of the invention in an inactive mode, and 
     FIG. 5 shows the spray head of FIG. 4 in an active mode. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 shows the spray head of the invention in a first, inactive mode. The spray head comprises a holder body  3  and a nozzle frame  1  fastened thereto by means of a spindle and comprising a number of nozzles  2 . The holder body  3 , in turn, is fastened to a pipeline  4  which supplies extinguishing medium to an inlet  5  in the holder body  3  and further to an upper portion  22  in the nozzle frame. 
     The holder body  3  is enclosed in a cylindrical sleeve  6 . The sleeve  6  is displaceable with respect to the holder body  3 . A pressure chamber  7  is arranged between the sleeve  6  and the holder body  3 . The pressure chamber  7  is formed because the sleeve  6  has a second cylindrical inner surface  8  whose diameter is larger than a first cylindrical inner surface  9  of the sleeve. The passage between the cylindrical surfaces  8  and  9  define a shoulder  10 . The pressure chamber  7  is also defined by a ring groove  11  provided in the holder body  3 . 
     The pressure chamber  7  is in contact with the inlet  5  via a passage which is generally denoted by reference numeral  12 . 
     The sleeve  6  is sealed against the holder body  3  by means of a first ring seal  23  in the first cylindrical inner surface  9  and a second ring seal  24  in the second cylindrical inner surface  8 . The ring seals  23 ,  24  are attached to ring grooves  25  and  26 , respectively, in the holder body  3 . This provides a simple structure. The sleeve  6  has corresponding, but shallow, ring grooves for the ring seals  23 ,  24 , the grooves being provided in the first cylindrical inner surface  9 . 
     The spray head comprises a cup-shaped cover  13  which covers the nozzles  2  and is installed by means of a ring seal  14  against a flange-like part  15  which, in turn, is fastened to the holder body  3 . The flange-like part  15  forms a ring groove  16  for the ring seal  14 . The cover  13  comprises a cylindrical groove  17  for receiving the ring seal  14 . The ring seal  14  is suitably somewhat pressed between the ring groove  16  and the cylindrical groove  17 . The cylindrical groove  17  and the ring seal  14  can be said to provide a locking device which holds the cover  13  in place in a protective position. Because of the ring seal  14 , the cover  13  is not only steadily attached to the spray head, but also the important components of the spray head, such as the nozzles  2 , are protected and hermetically sealed from the surroundings of the spray head. This is important since the spray head is intended to be used in various surroundings in which it is exposed to dirt which with time renders the spray head unusable or causes its operation to become unreliable without said cover  13 . 
     In FIG. 1, the cover  13  is in a protective position. The spray head in FIG. 1 can be placed in an active mode, shown in FIG. 3, by supplying pressurized liquid from the pipeline  4  to the passage  12 . This way a liquid pressure is created against the shoulder  10  (see FIG.  1 ), creating a force which tends to push the sleeve  6  downwards. The magnitude of the force is determined by the product of the liquid pressure and the projecting ring area that the shoulder  10  defines, seen in the longitudinal direction of the holder body (i.e. that of the pipeline  4 ). When the magnitude of the force exceeds the force needed to open the locking device created by the ring seal  14  and the groove  17 , the cover  13  comes off and is displaced by being pressed by the lower edge  21  of the sleeve in the position shown in FIG.  2 . 
     FIGS. 2 and 1 shows that the sleeve  6  comprises a stop  19  which bears on the flange-like part  15 . Consequently, the flange-like part can be called a blocking part  15 . 
     With the cover  13  in the position shown in FIG. 2, it falls from the spray head, is released from the sleeve  6  and is placed in a free position, as is shown in FIG.  3 . This way the spray head is in the active mode and is able to spray extinguishing medium. 
     The sleeve  6  comprises a third cylindrical inner surface  27  which is arranged to bear tightly on the ring seal  14  when the spray head shifts to the active mode. FIG. 2 shows that the ring seal  14  gives additional security against leakage if for some reason the ring seal  23  does not seal tightly. 
     An upper portion  30  in the sleeve  6  is high enough for the ring seal  24  to bear fluid-tightly on the holder body  3 . 
     The nozzle frame  1  and related components are not described here in greater detail, since suitable embodiments can be contemplated by a person skilled in the art. 
     It is feasible that the sleeve-like part  6  (and a passage  12 ) are omitted. In this case, with the pipe  4  pressurized, extinguishing fluid flows to the nozzles  2  of the spray head and to the space  29  between the nozzle frame  1  and the cover  13 . After filling the space  29 , the pressure of the extinguishing fluid makes the cover  13  come off. This kind of structure is very simple. 
     Reference numeral  28  denotes a fastening part for receiving the end of a chain or corresponding elongated element  49  whose other end is fastened near the spray head, for example to a pipeline. The element  49  prevents the cup  13  from being lost when the spray head shifts from the inactive to active mode. 
     FIGS. 4 and 5 show another embodiment of the spray head in passive and active modes, respectively. Like numerals are employed in FIGS. 4 and 5 to designate like components in FIGS. 1 to  3 . The nozzle frame  1 ′ and related components, for example a displaceable spindle  40 ′ loaded by means of a spring  48 ′ and comprising a duct  41 ′ for supplying extinguishing medium from the inlet  47 ′ of the nozzle frame to the nozzles  2 ′,  2 ′ c  can advantageously be of the pressure compensated (pressure balanced) type disclosed in publication WO 96/08291. The spray head does not have to be a pressure compensated spray head. A high pressure possibly acting in the inlet of the conduit leading to the nozzles  2 ′ does not reach the nozzles before the spindle is displaced. Once the spindle is displaced, with a closing part  42 ′ opening, a fluid communication between the inlet of the nozzle frame and the nozzles  2 ′ is opened to allow them to spray extinguishing medium. The embodiment in FIG. 4 differs from that in FIG. 1 in that the spray head can be shifted (provided the pipe  4  contains pressurized extinguishing medium) from the passive (inactive) to active mode by a separate line  45 ′ connected to the pressure chamber  7 ′ via a passage  46 ′ in the holder body  3 ′. Compared with the embodiment in FIG. 1, in certain application this would mean significant advantages which will be discussed below. 
     Accordingly, the pressure balanced spray head shown in FIG. 4 is preliminary activated/activated by means of a fluid pressure in the line  45 ′, called a control line, the fluid not having to be in connection with the extinguishing medium in the pipe  4 . Consequently, the fluid can be a gas. The fluid can also be the same as the extinguishing medium in the pipe  4 , for example water. The fluid in the control line  45 ′ is not in fluid communication with the inlet  5 ′ when the spray head is in the inactive mode. In the active mode of the spray head, the control line  45 ′ is/is not in fluid communication with the inlet, depending on the application. The advantage of the embodiment of FIG. 4 is that a fire extinguishing installation comprising separate or group-activated groups of spray heads can be provided at significantly lower costs than without a control line  45 ′. This is because the dimension of the control line  45 ′ can be significantly smaller than that of the extinguishing medium supply line, and a valve (not shown) for controlling the flow of fluid to the control line can be significantly smaller than a valve which controls the flow of extinguishing medium to the pipe  4 . Furthermore, the cover  13 ′ can be temporally displaced depending on whether the pipe  4  is pressurized or not, i.e. independently of whether or not liquid is supplied to the nozzles. In addition, the spray head can be made to initially spray only when both the line  45 ′ and the pipe  4  are pressurized. In case there is no liquid in the pipe  4 , said preliminary activation is involved, indicating only that the cover  13 ′ comes off. A spray head according to FIG. 4 can be used to construct a fire extinguishing system comprising a plurality of spray heads and a common pressurized extinguishing medium supply line (not shown), to which the pipes  4  of the spray heads are coupled, only the spray heads being released to whose control lines  45 ′ fluid is supplied. 
     As mentioned above, the spray head does not have to be pressure balanced, particularly in a ‘dry pipe’ system, for example, in which extinguishing medium pressure does not initially act in the inlet. Non-pressure balanced spray heads can also be used in wet pipe systems on account of the closing part  42 ′ which prevents the spindle  40 ′ from being pressed downwards by the spring  48 ′ when the spray head is in the passive mode and the cover  13 ′ is on. Once the pressure chamber  7 ′ is pressurized, the cover  13 ′ and the closing part  42 ′, fastened to the cover, are pressed downwards, resulting in the spindle  40 ′ being pressed downwards by the force of the spring  48 ′ and the extinguishing medium pressure, which is directed to the spindle. This way the spindle does not block the inlet  7 ′ and extinguishing medium can flow from the inlet  5 ′ via the conduit  41 ′ to the nozzles  2 ′,  2   c ′. With the spray head in the inactive mode shown in FIG. 4, the closing part  42 ′ is kept in place in the nozzle frame  1 ′ by means of locking means comprising a first locking part  54 ′ and a second locking part  55 ′. The first locking part  54 ′ is locked to the nozzle frame  1 ′ by means of displaceable elements  50 ′, for example metal spheres. The second locking part  55 ′ is fastened to the first locking part  54 ′ by means of an O ring  52 ′ positioned in a cylindrical groove  53 ′ in the second locking part  55 ′ when the spray head is in the inactive mode. The O ring  52 ′ holds the second locking part  55 ′ in place in the first locking part  54 ′, even though the cover  13 ′ is not yet installed. Owing to this, the final installation of the spray head becomes simple; only the cover  13 ′ has to be installed in the same place as the spray head is to be positioned, because the O ring  52 ′ and the locking parts  54 ′,  55 ′ can be (completely) installed at the factory. The second locking part  55 ′ is also fastened to an opening  58 ′ in the cover  13 ′. A pin  28 ′ or, in principle, any locking element can transfer the force from the cover  13 ′ to the second locking part  55 ′ such that it will move along once the cover is displaced. The shape of the second locking part  55 ′ allows a support  57 ′ to be formed against the opening  58 ′ of the cover. 
     The elements  50 ′ are arranged to be displaced in such a position that the first locking part  54 ′ is released from the nozzle frame  1 ′ when the second locking part  55 ′ is displaced with respect to the first locking part. This takes place when the cover  13 ′ is pressed downwards by means of pressure from the control line  45 ′. In this connection the spindle  40 ′ presses the first locking part  55 ′ out of the nozzle frame such that the spray head shifts to the active mode shown in FIG.  5 . 
     The invention has been described above only with reference to examples. It should be noted that the details of the invention may vary in many respects within the scope of the attached claims as compared with the examples. Instead of a sleeve-like part  6 , the use of another type of displaceable device is feasible, for example a piston device which under fluid pressure is displaced and opens the locking device which holds the cover in place.