Helmet-mounted air system for personal comfort

Abstract

A single lightweight thermoelectric module (TEM) is mounted in a housing in turn mounted centrally atop a helmet to be worn by a worker in a hot atmosphere. The heat abstraction side of the TEM is disposed within the housing, the heat dissipation side dissipates heat to the ambient atmosphere. It has been found that the personal comfort of the worker is surprisingly improved by flowing a very small stream, 3-15 SCFM, of cooled air across only his face if the temperature of the air stream is in the range from about 1° F. to 7° F. cooler than the ambient air. This discovery allowed the air duct carrying cooled air from downstream the heat abstraction side of the TEM to be less than about 1 ft long, presenting substantially insignificant pressure drop of air flowing through the duct. This allows the use of a miniature fan means to blow the air through the housing. Two thermistors sense the temperature of air upstream and downstream, respectively, of the heat abstraction side of the TEM. A manual selection means allows the worker to set the temperature difference of air he wishes to be delivered to his face. Surprisingly, the hotter the ambient, the closer to the maximum temperature difference (set by the worker) is the air delivered to him.

I claim: 
     
       1. A body-mountable apparatus for maintaining personal comfort of a person subjected to heat while wearing a helmet, by flowing cooled ambient air across said person's face only, said apparatus comprising, battery means removably mounted on said body;   a housing mounted on the surface of said helmet, said housing having an intake end for ambient air, and a discharge end for cooled air;   fan means mounted within said housing, adjacent said intake end, and electrically connectable to said battery means for selective on/off operation;   thermoelectric module means mounted through the wall of said housing and electrically connectable to said battery means, said module having a heat dissipation side, and, a heat abstraction side disposed within said housing, said heat abstraction side being in heat-conducting association with air flowing through said housing;   a first thermistor, upstream of said heat abstraction side, in temperature sensing association with air flowing through said intake end of said housing;   a second thermistor, downstream of said heat abstraction side, in temperature sensing association with air flowing to said discharge end;   manual selection means for selecting the temperature of air discharged from said housing;   temperature control means in operative communication with said manual selection means and said first and second thermistor means, and adapted to maintain a predetermined temperature difference between said first and second thermistors by regulating current supplied to said module, wherein such regulation of current is responsive to said manual selection means and the temperatures sensed by said first and second thermistors;   air-duct means attached at its one end to said discharge end of said housing, its other end terminating in front of said person's face to flow cooled air across said face; whereby said person wearing said helmet has untethered mobility.   
     
     
       2. The apparatus of claim 1 wherein said manual selection means is a switch for setting a desired temperature difference in the range from about 1° F. to 7° F. (1° C. to 4° C.) and selectively shuts off operation of said apparatus. 
     
     
       3. The apparatus of claim 2 wherein said switch is mounted directly upon said housing. 
     
     
       4. The apparatus of claim 2 wherein said switch is disposed on the body of said person, but distally disposed relative to said housing. 
     
     
       5. The apparatus of claim 1 including an air-filter demountably disposed on said intake end of said housing to filter incoming air. 
     
     
       6. The apparatus of claim 1 wherein said other end of said duct is provided with a nozzle means to direct said air across said face. 
     
     
       7. The apparatus of claim 1 wherein temperature of cooled air sensed by said second thermistor relative to ambient temperature is lower when said ambient temperature is highest and said desired temperature difference set is maximum. 
     
     
       8. The apparatus of claim 1 wherein said thermoelectric module is a Peltier-effect device and said heat dissipation side includes metallic fin means in open communication with the ambient atmosphere. 
     
     
       9. The apparatus of claim 1 wherein said air-duct means is less than about 1 ft (0.3 meter) long. 
     
     
       10. The apparatus of claim 1 wherein said fan means provides from 3 SCFM to 15 SCFM of air. 
     
     
       11. The apparatus of claim 1 wherein said housing is removably mounted on said helmet. 
     
     
       12. The apparatus of claim 1 wherein said housing is integrally formed on said helmet. 
     
     
       13. The apparatus of claim 1 wherein said battery means provides 9 volts. 
     
     
       14. The apparatus of claim 8 wherein said thermoelectric module is a single module. .Iadd. 
     
     
       15.  Apparatus for maintaining personal comfort of a person subjected to heat by flowing cooled ambient air across the person's face, the apparatus comprising: a power source;   a duct having an intake end for ambient air and a discharge end for cooled air;   fan means mounted within the duct and electrically connectable to the power source for selective on/off operation;   thermoelectric module means mounted through the wall of the duct and electrically connectable to the power source, the module having a heat dissipation side and a heat abstraction side disposed within the duct, the heat abstraction side being in heat-conducting association with air flowing through the duct;   manual selection means for selecting the temperature of air discharged from the duct;   temperature control means in operative communication with the manual selection means and adapted to establish a predetermined temperature of air being discharged through the discharge end of the duct; and   the discharge end of the duct terminating adjacent the person's face to flow cooled air across the face. .Iaddend..Iadd.16. The apparatus of claim   
     
     
        15, wherein the power source is a battery. .Iaddend..Iadd.17.  The apparatus of claim 15, wherein the power source is mounted on the person's body. .Iaddend..Iadd.18. The apparatus of claim 15, wherein the manual selection means is a switch. .Iaddend..Iadd.19. The apparatus of claim 15, further comprising: a first thermistor upstream of the heat abstraction side in temperature sensing association with air flowing through the intake end of the duct;   a second thermistor downstream of the heat abstraction side in temperature sensing association with air flowing to the discharge end; and   the temperature control means being in operative communication with the first and second thermistor means and adapted to maintain a predetermined temperature difference between the first and second thermistors by regulating current supplied to the module, the regulation of current being responsive to the manual selection means and the temperatures sensed by the first and second thermistors. .Iaddend..Iadd.20. Apparatus for maintaining personal comfort of a person subjected to heat while wearing a helmet, by flowing cooled ambient air across the person's face, the apparatus comprising:   a power source;   a housing included as part of the helmet, the housing having an intake end for ambient air and a discharge end for cooled air;   fan means mounted within the housing adjacent the intake end, and electrically connectable to the power source for selective on/off operation;   thermoelectric module means mounted through the wall of the housing and electrically connectable to the power source, the module having a heat dissipation side and a heat abstraction side disposed within the housing, the heat abstraction side being in heat-conducting association with air flowing through the housing;   manual selection means for selecting the temperature of air discharged from the housing;   temperature control means in operative communication with the manual selection means and adapted to establish a predetermined temperature of air discharged from the housing; and   an air duct attached at its one end to the discharge end of the housing and at its other end terminating adjacent the person's face to flow cooled air   
     
     
        across the face. .Iaddend..Iadd.21.  The apparatus of claim 20, wherein 
     
     
        the power source is a battery. .Iaddend..Iadd.22.  The apparatus of claim 20, wherein the power source is mounted to the person's body. .Iaddend..Iadd.23. The apparatus of claim 20, wherein the manual selection means is a switch. .Iaddend..Iadd.24. The apparatus of claim 20, further comprising: a first thermistor upstream of the heat abstraction side in temperature sensing association with air flowing through the intake end of the housing;   a second thermistor downstream of the heat abstraction side in temperature sensing association with air flowing to the discharge end; and   the temperature control means being in operative communication with the first and second thermistors and adapted to maintain a predetermined temperature difference between the first and second thermistors by regulating current supplied to the module, the regulation of current being responsive to the manual selection means and the temperatures sensed by the first and second thermistors. .Iaddend..Iadd.25. Control apparatus for maintaining a predetermined temperature difference between ambient air at a first temperature and ambient air at a second temperature that is cooler than the first temperature, comprising:   a power source;   a duct having an intake end for ambient air and a discharge end for cooled air;   fan means mounted within the duct and electrically connectable to the power source for selective on/off operation;   thermoelectric module means mounted through the wall of the duct and electrically connectable to the power source, the module having a heat dissipation side and a heat abstraction side disposed within the duct, the heat abstraction side being in heat-conducting association with air flowing through the housing;   a first thermistor upstream of the heat abstraction side in temperature-sensing association with air flowing through the intake end of the duct;   a second thermistor downstream of the heat abstraction side in temperature-sensing association with air flowing to the discharge end;   manual selection means for selecting the temperature of air discharged from the duct; and   temperature control means in operative communication with the manual selection means and the first and second thermistors, and adapted to maintain a predetermined temperature difference between the first and second thermistors by regulating current supplied to the module, wherein such regulation of current is responsive to the manual selection means and the temperature sensed by the first and second thermistors.   
     
     
        .Iaddend..Iadd.6.  The apparatus of claim 25, wherein the power source is a battery. .Iaddend..Iadd.27. The apparatus of claim 25, wherein the manual selection means is a switch. .Iaddend..Iadd.28. The apparatus of claim 25, further comprising: a housing within which the duct, fan means, thermoelectric module means, for thermistor, and second thermistor are disposed. .Iaddend..Iadd.29. The apparatus of claim 28, further comprising a helmet adapted to be worn by the person, the housing being included as part of the helmet. .Iaddend..Iadd.30. The apparatus of claim 29, further including an air filter demountably disposed on the intake end of the housing to filter incoming air. .Iaddend..Iadd.31. The apparatus of claim 29, wherein the power source is mounted to the person's body. .Iaddend.