Abstract:
A fire sprinkler including a generally tubular body having inlet and outlet ends is disclosed. The body defines a fluid flow passage extending between the inlet and the outlet such that the outlet is in fluid flow communication with the inlet. A magnetized member is disposed within the fluid flow passage and is movable between a first position wherein fluid flow communication between the outlet and the inlet is blocked and a second position wherein fluid flow communication between the outlet and the inlet is open. A temperature sensitive magnetic member is coupled to the body and has sufficient magnetic properties to attract the magnetized member below a predetermined temperature, thereby maintaining the magnetized member in the first position. The temperature sensitive magnetic member loses a sufficient percentage of its magnetic properties at and above the predetermined temperature, thereby allowing the magnetized member to move to the second position.

Description:
This application is the U.S. national phase application of PCT International Application No. PCT/US2008/001491, filed Feb. 5, 2008, which claims priority to U.S. Patent Application No. 60/900,585, filed Feb. 9, 2007, the contents of such applications being incorporated by reference herein in their entirety. 
     BACKGROUND OF THE INVENTION 
     Fire sprinklers are widely used in all kinds of buildings, including hotels, hospitals, shopping malls, and schools. Current fire sprinklers incorporate a plastic tube filled with a liquid that seals a passage in the sprinkler, precluding water flow from a pressurized water supply line through the sprinkler. When the plastic tube heats up, such as in the event of a fire, the liquid within the tube boils and generates a high vapor pressure, breaking the plastic tube and allowing fluid flow through the sprinkler. Once the tube is broken, the only way to stop water from spraying from the sprinkler is to cut off the water supply to the sprinkler, such as by closing a valve upstream of the sprinkler. Even if a fire is quickly extinguished, continued operation of water sprinklers may continue to damage the space in which the fire erupted. 
     U.S. Pat. No. 4,590,999 discloses embodiments of a magnetically operated fire sprinkler with a sealing device that loses its magnetism at a predetermined high temperature, opening the sprinkler and allowing water flow therethrough. The sealing device, however, loses a substantial amount of its magnetism upon returning to ambient temperature or, even without a high temperature event, over time, which may lead to leaks or may require replacement of the magnets after a fire event. 
     There exists a need to develop a water sprinkler and/or valve that operates in response to high temperatures generated by a fire, yet automatically shuts off water flow in response to a lower temperature, such as after the fire is extinguished, which operates magnetically and which comprises a magnetic switch which is permanently operable such that the parts of which do not need to be periodically replaced. 
     SUMMARY OF THE INVENTION 
     Briefly, an embodiment of the present invention provides a fire sprinkler. The fire sprinkler includes a generally tubular body having an inlet end and an outlet end. The body defines a fluid flow passage extending therethrough between the inlet end and the outlet end such that outlet end is in fluid flow communication with inlet end. A magnetized member is disposed within fluid flow passage and is movable between a first position wherein fluid flow communication between the outlet end and the inlet end is blocked and a second position wherein fluid flow communication the inlet end is blocked and a second position wherein fluid flow communication between the outlet end and the inlet end is open. A temperature sensitive magnetic member is coupled to the body and has sufficient magnetic properties to attract the magnetized member below a predetermined temperature, thereby maintaining the magnetized member in the first position. The temperature sensitive magnetic member loses a sufficient percentage of its magnetic properties at and above the predetermined temperature, thereby allowing the magnetized member to move to the second position. 
     Further, an alternative embodiment of the present invention provides a temperature-operated valve comprising a body having an inlet end and an outlet end. The body defines a fluid flow passage extending therethrough between the inlet end and the outlet end such that outlet end is in fluid flow communication with inlet end. A magnetized member is disposed within fluid flow passage and movable between a first position wherein fluid flow communication between the outlet end and the inlet end is blocked and a second position wherein fluid flow communication between the outlet end and the inlet end is open. A temperature sensitive magnetic member is coupled to the body and has sufficient magnetic properties to attract the magnetized member below a predetermined temperature, thereby maintaining the magnetized member in the first position. The temperature sensitive magnetic member loses a sufficient percentage of its magnetic properties at and above the predetermined temperature, thereby allowing the magnetized member to move to the second position. 
     Also, another embodiment of the present invention provides a method of operating a fire sprinkler comprising a magnetized member operatively disposed within a fluid flow path. The method comprises the steps of maintaining the magnetized member in a closed position, sealing the fluid flow path; heating the fire sprinkler to a predetermined temperature; releasing the magnetized member, opening the fluid flow path; cooling the fire sprinkler below the predetermined temperature; and retaining the magnetized member in the closed position, resealing the fluid flow path. 
     Additionally, another embodiment of the present invention provides a method of operating a valve. The valve has a body defining a fluid flow passage, a magnetized member disposed within the fluid flow passage, and a temperature sensitive magnetic member operatively couplable to the magnet. The method comprises the steps of magnetically attracting the magnetized member to a first position by the temperature sensitive magnetic member, thereby precluding fluid flow through the fluid flow passage; heating the temperature sensitive magnetic member to a predetermined temperature, thereby reducing magnetic attraction between the magnetized member and the temperature sensitive magnetic member; and moving the magnetized member to a second position, thereby allowing fluid flow through the fluid flow passage. 
     A further embodiment of the present invention provides a method of producing an alloy having a Curie temperature of about 66 degrees Celsius. The method comprises the steps of heating a combination of about 74 percent nickel and about 26% copper by weight to about 1500 degrees Celsius in the presence of an inert gas, forming an alloy and annealing the alloy at a temperature of between about 935 degrees Celsius and about 1100 degrees Celsius for at least 48 hours. 
     Also, an alternative embodiment of the present invention provides a fire sprinkler comprising a body having an inlet end, an outlet end, a fluid flow passage extending between the inlet end and the outlet end and a magnetized member disposed within the fluid flow passage, wherein the magnetized member is movable to operate the fire sprinkler between an open position and a closed position. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated herein and constitute part the specification, illustrate presently desired embodiments of the invention, and, together with the general description given above and the detailed description given below, serve to explain features of the invention. In the drawings: 
         FIG. 1  is an exploded perspective view and assembled perspective view of a fire sprinkler according to an exemplary embodiment of the present invention; 
         FIG. 2  is a side profile view, in section, of the fire sprinkler of  FIG. 1 , with the sprinkler in a closed position; 
         FIG. 3  is a side profile view, in section, of the fire sprinkler of  FIG. 1 , with the sprinkler in a open position; 
         FIG. 4  is a graph showing magnetization percent vs. temperature for a magnetic alloy according to the present invention; 
         FIG. 5  is a side profile view, in section, of a fire sprinkler according to an alternative exemplary embodiment of the present invention, with the sprinkler in the closed position; and 
         FIG. 6  is a side profile view, in section, of the fire sprinkler of  FIG. 5 , with the sprinkler in the open position. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Certain terminology is used in the following description for convenience only and is not limiting. The word “upstream” is used to define a direction closer to the inlet end of the fire sprinkler according to the present invention, and the word “downstream” is used to define a direction closer to the outlet end of the fire sprinkler according to the present invention. The word “magnetized” is used herein to describe an object that produces or possesses a magnetic field with sufficient strength to attract a magnetic object. As used herein, the word “magnetic” describes an object that does not produce a magnetic field with sufficient strength to attract another magnetic object, but may be attracted to a magnetized object. The terminology includes words specifically mentioned, derivatives thereof and words of similar import. The exemplary embodiments illustrated below are not intended to be exhaustive or to limit the invention to the precise form disclosed. These embodiments are chosen and described to best explain the principle of the invention and its application in practical use and to enable others skilled in the art to best utilize the invention. 
     The present invention provides a novel fire sprinkler and/or valve that automatically operates and secures itself, and is reusable. Further, the present invention provides a novel material that has temperature sensitive magnetic properties and is used to operate valve and/or the fire sprinkler in which the valve is included between a closed and open position. Additionally, the present invention provides a method for manufacturing the novel material. 
     While the operation of the invention is described with respect to a fire sprinkler, those skilled in the art will appreciate that the principles of operation discussed herein are equally applicable to any liquid flow valve having the structure described below. 
     Referring specifically to  FIGS. 1-3 , an exemplary embodiment of a fire sprinkler  100  according to the present invention is shown. Fire sprinkler  100  includes a generally tubular body  110  having an inlet end  112 , an outlet end  114 . Body  110  defines a fluid flow passage  116  extending through body  110  between inlet end  112  and outlet end  114  such that outlet end  114  is in fluid communication with inlet end  112 . Body  110  may be constructed from brass. Inlet end  112  may include a threaded connection  118  for threadably securing fire sprinkler  100  to an upstream water supply line, such as a fire sprinkler system (not shown). Inlet end  112  includes a necked down portion  113  that reduces the diameter of fluid flow passage  116  relative to the diameter of fluid flow passage  116  at outlet end  114 . Outlet end  114  includes internal threads  119 . 
     A valve plunger  120  is slidably disposed within fluid flow passage  116 . Valve plunger  120  includes an upstream sealing end  122  and a downstream end  124 . Upstream end  122  may be hemispherical or dome shaped and serves to seal fluid flow passage  116  at necked down portion  113  when fire sprinkler  100  is in a closed position. Valve plunger  120  further includes a plurality of exterior channels  126  extending between upstream sealing end  122  and downstream end  124 . Channels  126  allow flow of water  102  past valve plunger  120  when upstream sealing end  122  is disposed away from necked down portion  113  in order to allow flow of water  102  from inlet end  112 , past valve plunger  120 , and toward outlet end  114 . Valve plunger  120  may be constructed from brass, with upstream sealing end  122  being constructed from rubber or other suitable sealing material. 
     A magnetized member, such as a magnet  130 , is disposed within fluid flow passage  116  downstream of valve plunger  120 . Magnet  130  engages downstream end  124  of valve plunger  120  and longitudinally translates valve plunger  120  within fluid flow passage  116  to open or close fire sprinkler  100 . In the embodiment shown in  FIGS. 1-3 , magnet  130  is generally spherical, although those skilled in the art will recognize that magnet  130  may be other shapes that allow fluid flow around or through magnet  130  within fluid flow passage  116  when fire sprinkler  100  is in an open, or operating, position. Magnet  130  may be constructed from a Neodymium-Iron-Boron (NeFeBo) alloy with a nickel surface coating. The NeFeBo alloy was chosen for its strong and stable magnetism, which does not significantly lose its magnetic properties at relatively high (66 to 150 degrees Celsius) temperatures. Alternatively, magnet  130  may be constructed from any other suitable magnetized material with similar properties. 
     While separate magnet  130  and plunger  120  are disclosed, those skilled in the art will recognize that valve plunger  120  may be constructed from a magnetized material and magnet  130  may be omitted from fire sprinkler  100  in its entirety. 
     A thermally responsive magnetic member forms a sealing ring  140 . Sealing ring  140  includes a central opening  142  that is sized to allow sealing ring  140  to be disposed over threaded connection  118  and seat on body  110 . Sealing ring  140  is located exteriorly of body  110  and is exposed to external ambient temperature. 
     Sealing ring  140  may be constructed from a nickel-copper (NiCu) alloy that includes about 74% of nickel and about 26% of copper by weight. The alloy may be formed by cutting the nickel and copper into small pieces and melting the cut nickel and copper in a furnace at a temperature of at least about 1500° Celsius under an inert gas, such as argon. The melted nickel and copper is mixed together to form an alloy in a desired shape, such as a ring. The alloy is allowed to cool and is then annealed between about 935° Celsius and about 1100° Celsius for at least about 48 hours. 
     The alloy produced from this process has a Curie temperature of about 66° Celsius. The alloy exhibits magnetic properties at temperatures below about 66° Celsius and loses its magnetic properties rapidly at temperatures above about 66° Celsius, as shown in the graph of  FIG. 4 . As may be seen in  FIG. 4 , the annealing process provides the alloy with a sharp magnetic transition at a temperature between about 60° Celsius and about 70° Celsius. As shown in  FIG. 4 , a temperature of 66° Celsius corresponds to a magnetization percentage of approximately 28% for the disclosed alloy. Those skilled in the art, however, will recognize that any other material or alloy that has a magnetization curve similar to the curve shown in  FIG. 4  and that has a magnetization of about 26% or lower at about 66° Celsius or in the range of about 60 degrees Celsius to about 70 degrees Celsius may be used. 
     Referring back to  FIGS. 1-3 , an adjuster  150  is threadably coupled to outlet end  114  of body  110 . Adjuster  150  includes threads  152  that threadably couple to threads  119  inside fluid flow passage  116  proximate to outlet end  114  of body. Threads  152 ,  119  allow adjuster  150  to adjust the location of magnet  130  within fluid flow passage  116  to regulate flow of water  102  through passage  116  when fire sprinkler  100  is in operation. Adjuster  150  may be constructed from brass. 
     Adjuster  150  further includes an upstream end  154  on which magnet  130  is seated when fire sprinkler  100  is in an open condition and an outlet end  156  which discharges water  102  from fire sprinkler  100  when fire sprinkler  100  is in operation. A plurality of adjuster through-passages  158  extend through adjuster  150  between upstream end  154  and outlet end  156 . Adjuster through-passages  158  allow water to exit fluid flow passage  116  for discharge from fire sprinkler  100 . Adjuster through-passages  158  are shaped and spaced to provide a spray of water exiting fire sprinkler  100 . Adjuster  150  adjusts the position of magnet  130  within the fluid flow passage  116  and also holds magnet  130  within fire sprinkler  100  during an operational event, such as a fire. 
     In use, fire sprinkler  100  is coupled to a sprinkler system (not shown), such as by threading threaded connector  118  of body  110  into the sprinkler system such that inlet end  112  is in fluid flow communication with pressurized water  102  within the sprinkler system. Magnet  130  is magnetically attracted to sealing ring  140  due to magnetic properties of sealing ring  140  at ambient room temperature. Magnet  130  urges valve plunger  120  upward in fluid flow passage  116  such that upstream sealing end  122  of valve plunger  120  seals necked down portion  113 , precluding fluid flow through fluid flow passage  116 . 
     When sealing ring  140  is heated to a temperature of about 66° Celsius, such as for example, during a fire event, sealing ring  140  rapidly loses a sufficient percentage of its magnetic property, losing its attraction to magnet  130 . Magnet  130  falls due to gravity and/or upstream water pressure onto upstream end  154  of adjuster  150 , allowing valve plunger  122  to also fall, moving upstream sealing end  122  of valve plunger  120  away from necked down portion  113 . This movement allows pressurized water  102  from the sprinkler system to flow through inlet end  112  and through fluid flow passage  116 . In addition to gravity pulling valve plunger  120  downward within fluid flow passage  116 , the force of the pressurized water  102  against upstream sealing end  122  also forces valve plunger  120  away from necked down portion  113 . The pressurized water  102  flows through channels  126  between valve plunger  120  and inlet end  112 , around magnet  130  and into adjuster through-passages  158 , where the water  102  is discharged from fire sprinkler  100 . 
     When sealing ring  140  cools to a temperature below about 66° Celsius, sealing ring  140  regains its magnetic properties, attracting magnet  130  upward, which forces valve plunger  120  against necked down portion  113 , resealing fluid flow passage  116  and stopping the flow of water  102  from the sprinkler system through fire sprinkler  100 . In order for fire sprinkler  100  to close during operation, the magnetic attraction between magnet  130  and sealing ring  140  must overcome both the weight of magnet  130  and the force of water  102  against magnet  130  as water  102  flows through fluid flow passage  116 . 
     An alternative embodiment of a fire sprinkler  200  is shown in  FIGS. 5 and 6 . Fire sprinkler  200  is similar to fire sprinkler  100 , except that fire sprinkler  200  utilizes a magnet  230  that is generally disc shaped. Magnet  230  may include through passages  232  that allow fluid to flow from an upstream end of magnet  230 , through magnet  230 , to a downstream end of magnet  230 . An adjuster  250  includes and upstream end  254  that includes a plurality of raised nubs  255  on which magnet  230  sits when fire sprinkler  200  is in an open or discharge condition. Nubs  255  allow fluid flowing from the downstream end  236  of magnet  230  to flow between magnet  230  and adjuster  250 , and through adjuster through passages  258  for discharge from fire sprinkler  200 . 
     Fire sprinklers  100 ,  200  each disclose a magnet  130 ,  230 , respectively, disposed within fluid flow passage  116  and sealing ring  140  disposed outside of fluid flow passage  116 . Magnets  130 ,  230  are each disposed within fluid flow passage  116  in order to allow water  102  to flow over magnets  130 ,  230 , during operation of fire sprinklers  100 ,  200  in order to cool magnets  130 ,  230 . Excessive heating of magnets  130 ,  230  may cause magnets  130 ,  140  to lose at least some of their magnetization over time, resulting in loss of magnetic attraction between magnets  130 ,  230  and sealing ring  140 , allowing leakage of water  102  from fire sprinklers  100 ,  200  in non-fire events. 
     Although the invention is illustrated and described herein with reference to specific embodiments, the invention is not intended to be limited to the details shown. Rather, various modifications may be made in the details within the scope and range of equivalents of the claims and without departing from the invention.