Abstract:
A gas hot air gun includes a main body, an ignition device, a switch set and a safety switch. The main body includes a blower, a nozzle, a barrel and a handle. A heating chamber and a mixing chamber are on the inner front of the barrel. A gas can is inside the handle. One end of the nozzle is connected to the gas can. The switch set includes a power switch, with the safety switch closing power of the battery set or gas flow of the gas can under some pre-set conditions. Users press the power switch and have gas spray out from the nozzle into the heating chamber to generate heat. The blower sends hot air in the heating chamber out of the main body. A metal slice regulating the direction of air and a catalyst for avoiding flame extending out of the nozzle area are inside the heating chamber.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     I. Field of the Invention  
         [0002]     This invention relates generally to a hot air gun and, more specifically, to a gas hot air gun that offers smaller physical size for users to carry around, complete burn of gas to reduce carbon mono-oxide and faster cooling down the whole set after application to prevent users from danger of burn, a safety switch closes power or gas flow under some pre-set conditions for safety purpose.  
         [0003]     II. Description of the Prior Art  
         [0004]     Heretofore, it is known that the “Internal structure of a hot air gun” of Taiwan listed pattern no. 286505 comprises of a main body  1 , a handle  2  and a power supply  3 ; the main body  1  connects to the handle with a hinge  11 ; the main body further comprises a motor  14 , a fan  15  is on the motor axis  141  of the motor  14 , a fan blade  16  in on the front of the fan  15 , a burning chamber  161  is beneath the fan blade  16 , an ignition tube  17  interlinks to the burning chamber  161  a temperature control switch  18  and a control rod  19  are installed inside the ignition tube  17 ; a power supply  3  and gas are inside the handle  2 , a flow control knob  23  is on top of the handle  2 , a flame nozzle  24  is on the front of the flow control knob  23 , the flame nozzle  24  is ignited inside the burning chamber  161  beneath the fan blade  16 , a press button  25  and switch  26  are installed on the handle to ignite gas and turn the motor  14  on.  
         [0005]     Many drawbacks exist on the known gas hot air gun, the flame burn the gas in the burning chamber  161  beneath the fan blade  16  after the gas is ignited, hot air is flown out by the fan blade  16  of the fan  15 ; however the flame inside the burning chamber  161  is blown out easily to burn users, such is not very safe, the temperature control switch  18  reduces the gas quantity after the temperature is high, when temperature is low the gas quantity is increased to have larger flame, such design introduces not complete burning of gas, the air injected might contain large quantity of carbon mono-oxide, it is very dangerous for users to apply the equipment in a sealed environment.  
       SUMMARY OF THE INVENTION  
       [0006]     It is therefore a primary object of the invention to provide a gas hot air gun that improves the known hot air guns often have the flame blown out easily to burn users, such is not very safe; the temperature sensor reduces the amount of gas when the temperature is too high and increases the amount of gas when the temperature is too low to make larger flame, such design introduces not complete burning of gas, the air injected might contain large quantity of carbon mono-oxide.  
         [0007]     In order to achieve the objective set forth, a gas hot air gun in accordance with the present invention comprises a main body, an ignition device, a switch set and a safety switch; the main body further comprises of a blower and a nozzle, the main body has a barrel and a handle as appearance; a heating chamber and a mixing chamber are on the inner front of the barrel, a battery set and a gas can are inside the handle, one end of the nozzle is connected to the gas can, the switch set further comprises of a power switch and an ignition switch, the safety switch connects to the switch set electrically, the safety switch closes power of the battery set or gas flow of the gas can under some pre-set conditions; users press the power switch and have gas spray out from the nozzle into the heating chamber to generate heat, the blower sends out hot air in the heating chamber out of the main body; a metal slice to regulate the direction of air and a catalyst to avoid flame out of the nozzle area are inside the heating chamber. The present invention is small in size and easy for users to carry.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]     The accomplishment of the above-mentioned object of the present invention will become apparent from the following description and its accompanying drawings which disclose illustrative an embodiment of the present invention, and are as follows:  
         [0009]      FIG. 1  is a perspective view of the present invention;  
         [0010]      FIG. 2  is an assembly view of the present invention;  
         [0011]      FIG. 3  is a cross-sectional view of the present invention;  
         [0012]      FIG. 4  is an application view of the present invention;  
         [0013]      FIG. 5  is a cross-sectional view of a further embodiment of the present invention;  
         [0014]      FIG. 6  is another cross-sectional view of a further embodiment of the present invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0015]     Referring to  FIG. 1  to  FIG. 6 , the present invention comprises a main body  10 , an air blower  20 , an ignition device  30 , a nozzle  40 , a switch set  50  and a safety switch  60 ; the main body  10  further consists of a barrel  11  and a handle  12 , a heating chamber  111  is inside the barrel  11 , a gas can  122  is inside the handle  12 , users can press the switch set  50  to start the safety switch  60  and have the gas of the gas can  122  spray out from the nozzle  40  into the heating chamber  111 , the ignition device  30  ignites the gas inside the heating chamber  111  to generate heat source, the air blower  20  blows the hot air inside the heating chamber  111  externally to the main body  10 .  
         [0016]     The main body  10  comprises of a barrel  11 , a handle  12 , an intake  13  and a exhalation hole  14 ; a heating chamber  111  and a mixing chamber  112  are on the inner front of the barrel  11 , a daisy shape metal slice  113  and a catalyst  114  are inside the heating chamber  111 , the metal slice  113  is installed inside the heating chamber  111  near the front side of the barrel  11 , the catalyst  114  is installed near the end of the barrel  11 ; a burning chamber  115  is inside the metal slice  113 , the mixing chamber  112  in installed on the barrel  11  that is opposite to the location of the heating chamber  111 ; a shrink  116  near the metal slice  113  is formed on one end of the mixing chamber  112 , the shrink  116  is interlinked to the burning chamber  115  of the metal slice  113 ; several air inhalation holes  117  are around the mixing chamber  112 , a passages  118  is between the metal slice  113  and the barrel  11 ; a tube shape metal net  119  to control the mixing air flow is installed between the burning chamber  115  of the metal slice  113  and the shrink  116  of the mixing chamber  112 , a thicker metal net  120  with smaller net holes near the exhalation hole  14  is on one side of the metal net  119 . The handle  12  is connected to and beneath the barrel  11 , a first container  123  and a second container  124  are inside the handle  12 , a battery set  121  and a gas can  122  are inside the first and the second container  123 ,  124  respectively, the gas can  122  contains burnable fluid, usually is liquid gas; a movable cover  125  is on the bottom of the handle  12  to cover the first and the second container  123 ,  124 . The intake  13  is installed on the end of the barrel  11  for air to flow into the barrel  11 ; several protective grids  131  are on the intake  13  to prevent users from inserting their fingers in. The exhalation hole  14  is on the front of the barrel  11  to expel air from the barrel  11 .  
         [0017]     The air blower  20  in installed internally on the end of the barrel  11  to draw air from the intake  13  into the barrel  11 , a DC motor is applied in this application, the blower  20  further comprises a motor  21 , a fan blade  22  and a temperature sensor  23 ; the motor  21  locates near one side of the exhalation hole  14 , the fan blade  22  is installed on the motor  21  and near one side of the intake  13  to be driven by the motor  21 ; the temperature sensor  23  is installed around the barrel  11  near the heating chamber  111 , the temperature sensor  23  controls the motor  20 , after end of application and when the temperature of the heating chamber  111  below certain temperature, the temperature sensor  23  stops the motor  21  from turning.  
         [0018]     The ignition device  30  is installed inside the metal slice  113  of the heating chamber  111  to ignite the mixed gas in the heating chamber  111 ; the ignition device  30  is installed inside the burning chamber  115  of the metal slice  113  in this application.  
         [0019]     The nozzle  40  is installed inside the barrel  11  of the main body  10  and located between the blower  20  and the mixing chamber  112 ; one end of the nozzle  40  is connected to the gas can  122 .  
         [0020]     The switch set  50  is installed inside the handle  12  of the main body  10  near the barrel  11 ; the switch set  50  further comprises of a power switch  51 , a control rod  52 , an ignition switch  53  and a regulation valve  54 ; the control rod  52  controls open and close of the gas can  122 , the ignition switch  53  connects to the ignition device  30  with electrical wires; the regulation valve  53  is installed on the gas can  122  to control the gas flow amount of the gas can  122 .  
         [0021]     The safety switch  60  connects to the power switch  51 , the safety switch  60  also connects to the motor  21 , the temperature sensor  23  of the blower  20 , the battery set  121  on the handle  12  and the control rod  52  of the switch set  50 , all these components are controlled by the safety switch  60  to turn on and off.  
         [0022]     Referring to  FIG. 4 , when the power switch  51  is pressed on, the safety switch  60  is activated, the safety switch  60  turns on the control rod  52  to open the gas can  122 , the gas sprays out from the nozzle  40 ; at the same time, the safety switch  60  activates the blower  20  blow air from the intake  13  into the mixing chamber  112  to mix the gas and the air blown in; when the mix gas passes the shrink  116 , with the shrinking diameter of the shrink  116 , the mixed gas is compressed, the mixed air spays out the shrink  116  at a faster speed, the high speed injected mixed air entering the burning chamber  115  of the metal slice  113  flows to the tube shape metal net  119  that guides the flow direction of the mixed gas (referring to  FIG. 5 ), with the two blocks by the thicker metal net  120  on the front of the tube shape metal net  119  and the tube shape metal net  119  itself, since the net holes of the thicker metal net  120  is smaller, the mixed gas is blocked effectively to have most of the mixed gas spays out in all directions. When the ignition switch  53  is pressed, the ignition device  30  ignites the mixed gas and generates flame, the flame expands several tongue of flames from the burning chamber  115  to surround the metal slice  113  and have the temperature of the metal slice  113  rise gradually that forms the first burning; with the better heat exchange rate of the metal slice  113 , when the air flow sent by the blower  20  passes through the passage  118  of the metal slice  113 , air flow can bring the heat on the metal slice  113  to generate hot air; when the hot air passes through the catalyst  114 , the catalyst  114  burns the small quantity left-over gas to reduce the quantity of carbon mono-oxide (CO) that forms the second burning; after two times of burning, the air temperature is higher, the air is safer, the catalyst  114  avoids the burning flame in the metal slice  113  from coming out of the exhalation hole  14 .  
         [0023]     The mixed gas needs to have a good ratio of fresh air and gas to be properly burnt, when oxygen contained is too low in the mixed gas, the inhalation holes  117  around the burning chamber  115  offers fresh air; the diameter of the shrink  116  of the mixing chamber shrinks  112  gradually, fresh air is sucked in, mixed with gas and enters the burning chamber  115  to be burnt stably; the quantity of gas can also be controlled by the regulation valve  54 ; since the metal slice  113  inside the heating chamber  111  has very good heat conductivity, the temperature of the metal slice  113  is lifted rapidly after the ignition inside the burning chamber  115 ; if the gas in the heating chamber  111  is not burnt properly, the toxic carbon mono-oxide is generated and is harmful to human body; in order to achieve complete burning, the catalyst  114  can achieve such purpose, the catalyst  114  reacts with the burning gas and generates non-toxic carbon di-oxide, the catalyst  114  can also prevent the flame from coming out of the exhalation hole  14 .  
         [0024]     When following situations happen, the safety switch  60  elaborates the proper function; when power switch  51  is on without flame or gas burning stops, the temperature sensor  23  installed on the barrel  11  near the heating chamber  111  detects the temperature did not reach the expected temperature, the safety switch  60  stops all the signals to make the motor  21  stop, the control rod  52  break away to stop the gas. At normal operation, when the temperature sensor  23  detects abnormal high temperature, the safety switch  60  have the control rod  52  stop the gas and have the motor  21  turn on to blow air until temperature drop and then stop. When temperature sensor  23  detects the temperature remain high after the power switch  51  is off, the safety switch  60  have the nozzle  40  stop spraying gas and turn on the blower  20 , the blower  20  keeps blowing fresh air to cool the temperature of the heating chamber  111 , the metal slice  113  absorbs the cold fresh air to lower the temperature of the heating chamber with the good heat conductivity, when the temperature sensor  23  detects the temperature of the heating chamber  111  reach low temperature, the blower  20  is turned off; such design makes the present invention easier to carry without the danger of burn.  
         [0025]     Referring to  FIG. 6 , when the safety switch  60  detects the battery set  121  in low battery condition or gas can  122  has insufficient gas to introduce the burning temperature drop, the safety switch  60  blocks all the signals to stop all operations; either battery set  121  or gas can  122  is out, new battery set  121  or gas can  122  can be replaced; the replacement is very convenient, users only need to lift the movable cover  125  and take the battery set  121  or gas can  122  out from the first or the second container  123 ,  124  respectively and do the replacement; the gas can  122  can be re-fill type can; the present invention applies gas to generate high temperature to avoid the troublesome of power cord and reduce the space, users are very convenient to carry the present invention around.  
         [0026]     While a preferred embodiment of the invention has been shown and described in detail, it will be readily understood and appreciated that numerous omissions, changes and additions may be made without departing from the spirit and scope of the invention.