Abstract:
A fire prevention sprinkler system that has a warming jacket through which a warming medium, preferably water, is circulated, at a temperature sufficient to prevent freezing of those portions of the sprinkler system that contain water or another freezable liquid at times when the sprinklers are not actually spraying water to control or extinguish a fire. The warming medium is preferably heated by radiant heating, and circulation is preferably initiated by a thermostatic control whenever the temperature in the protected premises drops below a predetermined value.

Description:
RELATED APPLICATION 
       [0001]    This application claims benefit under 35 U.S.C. §119(e) of provisional A.N. 61/563,118, filed Nov. 23, 2011, the entire contents of which are incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    This disclosure relates generally to fire prevention sprinkler systems, and more particularly to a fire prevention sprinkler system that can prevent freezing of the system even during cold weather. It further relates to a fluid-distribution system to supply a fluid to a system of fire-prevention sprinklers to prevent freezing thereof. 
         [0004]    2. Description of Related Art 
         [0005]    Freezing weather is a danger to fire prevention sprinklers, as to other plumbing systems, if water is present in the sprinklers or associated piping and is allowed to freeze. When the sprinklers and associated piping are located in premises that are kept above freezing temperature at all times, this is not a problem. 
         [0006]    Where the sprinklers must provide protection for unheated premises, such as some warehouses, loading docks, concealed spaces, or attics, it is not economical to heat the premises just to protect the sprinkler system. One common approach to solving that problem is to retain the water in a portion of the piping system that is in a heated area, and to maintain the sprinklers themselves dry except when in actual operation applying water. These “dry” sprinklers are expensive, and the water in the system piping must remain above freezing temperatures. 
         [0007]    Another method for sprinkler protection in freezing conditions is to use a dry pipe sprinkler system. This system uses an air compressor or nitrogen to fill the sprinkler system piping. The sprinklers must be of the dry type. When a sprinkler operates, a control valve opens and allows water to flow into the piping system and discharge from the now-open sprinkler or sprinklers. There is a time delay in providing water application to the fire, which must be determined and taken into account to provide proper fire protection. Such a system requires special installation to prevent trapping of water in the piping system and the equipment, and dry sprinklers are very expensive in comparison to a standard wet pipe sprinkler system. 
         [0008]    Another method is to fill the sprinkler system piping with a mixture of water and an antifreeze solution. Recent studies have shown, however, that high percentages of antifreeze can cause actually be dangerous to occupants in the fire area. This is also a relatively expensive method of providing freeze protection due to the cost of materials, and inspection and maintenance requirements. 
         [0009]    All of these methods are impractical for certain types of premises, and they each add a significant cost to provide freeze protection to a fire sprinkler system. 
       SUMMARY 
       [0010]    It is desired to provide a fire prevention sprinkler piping system that can prevent freezing even when used at low temperatures. It is also desired to provide a fluid-distribution system that can distribute a heated fluid to a fire prevention sprinkler system to prevent freezing. 
         [0011]    Some embodiments disclosed herein may utilize an active heat source or generator to provide heat to warm the warming medium fluid. In particular, some embodiments may utilize a radiant heating system to heat the warming medium. 
         [0012]    Other sources of heat to warm the medium can be used, examples including water heaters, geo-thermal devices, boilers, and other heat transfer equipment. 
         [0013]    A passive heating system may be used in some embodiments. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING FIGURES 
         [0014]      FIG. 1  is a diagram illustrating schematically the arrangement of elements in one embodiment. 
           [0015]      FIGS. 2A and 2B  illustrate schematically two alternative arrangements that may be used in the embodiment of  FIG. 1 . 
           [0016]      FIG. 3  is a diagram illustrating schematically the arrangement of elements in another embodiment. 
           [0017]      FIG. 4  is a diagram further illustrating the arrangement of elements in the embodiment of  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0018]    As shown in  FIG. 1 , a number of fire prevention sprinklers  12  are installed at various locations in the premises to be protected against fire. In addition to the normal fire sprinkler piping  14  (not illustrated in  FIG. 1 ) that serves to deliver water (or another fire-extinguishing medium) to the sprinklers  12 , a line (“warming medium path”)  16  is provided that distributes a warming medium, preferably water from a water supply  10 , along or through the fire sprinkler piping and to each of the fire sprinklers  12 . In this embodiment the warming medium path  16  is structured as a warming jacket for the fire sprinkler piping  14 , that is, it is located adjacent to and thermally coupled to, and may at least partially surround the circumference of, that piping  14  (see  FIG. 2A ). A heat source  18  heats the warming medium  20  to an appropriate temperature, and a pump  22  serves to deliver the warmed medium to the sprinklers  12  via the warming medium path  16 . The warming medium  20  is returned to its source via a return line  24 . 
         [0019]    Preferably, a thermostatic control  26  is located in the protected premises, and is coupled to actuate the heat source  18  and pump  22  as needed. It is particularly contemplated to actuate the pump  22  and heat source  18  to cause them to heat and distribute the warming medium  20  whenever the temperature in the premises falls to a certain level. For example, that level may be 50° F. (10° C.). In the illustrated example, when the temperature in the premises is measured as being below that value, the heat source  18  and pump  22  are actuated, and the warming medium  20 —in this case, water—is heated to a higher temperature, such as 60° F. (about 15° C.), and circulated through the system to maintain the sprinklers  12  above freezing temperature. 
         [0020]    The circulated warming medium  20  also warms the pipes  14  that supply water to the sprinklers  12 , to ensure that those pipes  14  also do not freeze. 
         [0021]    The thermostatic control  26  may utilize a thermometer  28  or equivalent device (see  FIG. 2B ) in the protected premises to measure the air temperature there, and to provide an electrical or other signal via wiring  30  or other means whenever the air temperature falls below the set level (50° F. or 10° C. in the above example). Alternatively, the thermometer  28  may provide periodic or continuous signals indicating the present air temperature, in which case the thermostatic control  26  may determine when the air temperature is below the set level. 
         [0022]    In another approach, illustrated in  FIG. 2A , the thermometer  28  or equivalent device may measure the temperature of the water or other fire extinguishing fluid  36  at one or more points in the sprinkler system, and transmit an electrical or other signal when the temperature of that water or other extinguishing fluid falls below a set temperature (it should be noted that the arrows in  FIG. 2A  do not necessarily indicate the direction of flow of either fluid, and should not be understood as meaning that both fluids are in motion at one time). 
         [0023]    A higher or lower value for the premises temperature can be used to determine when the system is to be activated, and could in principle be any desired temperature that is sufficiently above 40° F. (about 4° C.) to provide certainty that the sprinklers  12  and the pipes  14  that supply them will not freeze. Similarly, the temperature to which the warming medium  20  is heated need not be 60° F., although it is believed that this temperature is a favorable one in terms of ensuring that the sprinkler system will not freeze, while not requiring excessive energy or cost to heat the medium beyond what is necessary. 
         [0024]    As mentioned, radiant heating is preferred as the active heat source  18 , but other heat sources may be used instead, including water heaters, geo-thermal devices, boilers, and other types of known heat transfer equipment. 
         [0025]    As an alternative to an active heat source, it is also contemplated to use a passive system for providing heat to the warming medium. In such a system, illustrated in  FIG. 3 , a number of fire prevention sprinklers  12  are installed at various locations in the unheated portion of the premises to be protected against fire, and a line is provided as a warming medium path  16  to distribute the warming medium  20 , preferably water, along or through the fire sprinkler piping  14  and to each of the fire sprinklers  12  as in the embodiment of  FIG. 1 . This warming medium path  16  is arranged to pass at point  38  into a heated portion of the premises, to be warmed there, and then passes at  40  back into the unheated portion of the premises and circulates the warming medium  20  to the sprinklers  12 . The warming medium path  16  in the unheated portion may be made of cross-linked polyethylene (“PEX”) as one suitable material, although other materials may be used instead. 
         [0026]      FIG. 4  illustrates another portion of the embodiment of  FIG. 3 . The warming medium path passes from the unheated premises (which may for example be the attic of a residence, or an unheated portion of other types of premises), and is formed as a spiral  32  through which the warming medium  20  circulates before passing through a circulating pump  22  back into the unheated portion of the premises shown in  FIG. 3 . The spiral or helix  32  may be positioned surrounding a portion of the piping of the heating system or the hot-water supply system of the premises, as two examples. 
         [0027]    The domestic water supply may be the source of water to be used as the warming medium, via check valve  34 ; this is also the case with the embodiment of  FIG. 1 . 
         [0028]    While various example embodiments of the present invention have been described above, it should be understood that they have been presented by way of example, and not limitation. It will be apparent to persons skilled in the relevant art(s) that various changes in form and detail can be made therein. Thus, the present invention should not be limited by any of the above described example embodiments, but should be defined only in accordance with the following claims and their equivalents. 
         [0029]    Further, the purpose of the accompanying Abstract is to enable the U.S. Patent and Trademark Office and the public generally, and especially the scientists, engineers and practitioners in the art who are not familiar with patent or legal terms or phraseology, to determine quickly from a cursory inspection the nature and essence of the technical disclosure provided herein. The Abstract is not intended to be limiting as to the scope of the example embodiments presented herein in any way.