Patent Publication Number: US-2010116814-A1

Title: Heating Process that Keeps a Heating Apparatus at a Constant Temperature by the Power Supply of a Portable Battery

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a heating process and, more particularly, to a heating process for a heating apparatus. 
     2. Description of the Related Art 
     A conventional heating apparatus in accordance with the prior art shown in  FIG. 5  comprises a control plate  12  mounted between a portable battery  11  and a heating module  13 . The control plate  12  is provided with at least one resistor  121  connected with the portable battery  11  and a transistor  122  connected with the heating module  13 . Thus, the portable battery  11  supplies an electric power to the heating module  13  so as to increase the temperature of the heating module  13 . However, the voltage of the portable battery  11  is decreased gradually when the discharging time of the portable battery  11  is increased, so that the current of the portable battery  11  is decreased gradually, and the temperature of the heating module  13  is decreased gradually (the resistance of the heating module  13  is fixed). Thus, the temperature of the heating module  13  cannot be kept at a constant value when the power supply of the conventional heating apparatus is supplied by a portable miniature battery. 
     Another conventional heating apparatus in accordance with the prior art shown in  FIG. 6  comprises a temperature controller  22  mounted between a portable battery  21  and a heating module  23 . The temperature controller  22  is provided with a control IC (integrated circuit)  221  connected between the portable battery  21  and the heating module  23 . Thus, the portable battery  21  supplies an electric power to the heating module  23  so as to increase the temperature of the heating module  23 . In practice, the control IC  221  of the temperature controller  22  can control the on/off percentage (or frequency) of the duty cycle of the portable battery  21 . In such a manner, when the on percentage of the duty cycle of the portable battery  21  is increased, the current of the portable battery  21  is increased, and the temperature of the heating module  23  is increased, and when the off percentage of the duty cycle of the portable battery  21  is decreased, the current of the portable battery  21  is decreased, and the temperature of the heating module  23  is decreased. Thus, the control IC  221  of the temperature controller  22  can control the on/off percentage (or frequency) of the duty cycle of the portable battery  21  to control the temperature of the heating module  23  in multiple steps. However, the voltage of the portable battery  21  is decreased gradually when the discharging time is increased, so that the current of the portable battery  21  is decreased gradually, and the temperature of the heating module  23  is decreased gradually (the resistance of the heating module  23  is fixed). Thus, the temperature of the heating module  23  cannot be kept at a constant value when the power supply of the conventional heating apparatus is supplied by a portable miniature battery. 
     BRIEF SUMMARY OF THE INVENTION 
     In accordance with the present invention, there is provided a heating process for a heating apparatus. The heating apparatus includes a portable battery, a controller connected to the portable battery, and a heating module connected to the controller by two connecting wires. The heating process includes providing a preset temperature and providing a software program in the controller. The software program of the controller previously detects a voltage variation of the portable battery to change an on/off percentage of a duty cycle of the portable battery and to regulate an output current of the portable battery according to the preset temperature and the detected voltage variation of the portable battery, so that the input current of the heating module is kept at a constant value, and the temperature of the heating module of the heating apparatus is kept at a constant value of the preset temperature at any time. The software program of the controller decreases the on percentage of the duty cycle of the portable battery and increases the off percentage of the duty cycle of the portable battery when the voltage of the portable battery is grater than a working voltage of the portable battery so as to decrease the output current of the portable battery. The software program of the controller increases the on percentage of the duty cycle of the portable battery and decreases the off percentage of the duty cycle of the portable battery when the voltage of the portable battery is smaller than the working voltage of the portable battery so as to increase the output current of the portable battery. 
     The primary objective of the present invention is to provide a heating process that keeps a heating apparatus at a constant temperature by the power supply of a portable battery. 
     Another objective of the present invention is to provide a heating process, wherein the controller previously detects the voltage variation of the portable battery to randomly change the on/off percentage of the duty cycle of the portable battery and to regulate (decrease or increase) the output current of the portable battery according to the detected voltage variation of the portable battery, so that the input current of the heating module is kept at a constant value, and the temperature of the heating module of the heating apparatus is kept at a constant value (the preset temperature) at any time even if the voltage of the portable battery is changed at any time. 
     Further benefits and advantages of the present invention will become apparent after a careful reading of the detailed description with appropriate reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) 
         FIG. 1  is a block diagram of a heating apparatus in accordance with the preferred embodiment of the present invention. 
         FIG. 2  is a circuit layout of a controller of the heating apparatus as shown in  FIG. 1 . 
         FIG. 3  is a discharging profile of a portable battery of the heating apparatus as shown in  FIG. 1 . 
         FIG. 4  is a profile of an on/off action of a duty cycle of the portable battery of the heating apparatus as shown in  FIG. 1 . 
         FIG. 5  is a block diagram of a conventional heating apparatus in accordance with the prior art. 
         FIG. 6  is a block diagram of another conventional heating apparatus in accordance with the prior art. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     First of all, when the power supply of a heating apparatus is supplied by an AC (alternating current) power supply or a steady-state DC (direct current) power supply, the voltage of the power supply is constant at any time, so that the current of the power supply is constant, and the temperature of the heating apparatus is constant at any time. Thus, the heating apparatus is kept at the state of a constant temperature to function as a thermostat so as to keep the temperature at a constant value. On the contrary, when the power supply of the heating apparatus is supplied by a portable miniature battery (such as a lithium battery), the voltage of the battery is decreased gradually when the discharging time is increased, so that the current of the battery is decreased gradually, and the temperature of the heating apparatus is decreased gradually. Thus, the heating apparatus cannot be kept at the state of a constant temperature when the power supply of the conventional heating apparatus is supplied by a portable miniature battery. 
     Therefore, a heating process in accordance with the preferred embodiment of the present invention is used to keep a heating apparatus at a constant temperature by the power supply of a portable miniature battery (such as a lithium battery). 
     Referring to the drawings and initially to  FIG. 1 , a heating apparatus in accordance with the preferred embodiment of the present invention comprises a portable battery  31 , a controller  3  connected to the portable battery  31 , and a heating module  33  connected to the controller  3  by two connecting wires  32 . The controller  3  is provided with a software program that previously detects the voltage variation of the portable battery  31  to control an on/off percentage (or frequency) of a duty cycle of the portable battery  31 . Thus, the temperature is preset when the portable battery  31  is started. Then, the controller  3  previously detects the voltage variation of the portable battery  31  to change the on/off percentage of the duty cycle of the portable battery  31  and to regulate the output current of the portable battery  31  according to the preset temperature and the detected voltage variation of the portable battery  31 , so that the input current of the heating module  33  is kept at a constant value, and the temperature of the heating module  33  of the heating apparatus is kept at a constant value (the preset temperature) at any time. 
     In practice, referring to  FIG. 2  with reference to  FIG. 1 , the controller  3  is provided with a control IC (integrated circuit)  34 . The seventh leg  345  of the control IC  34  is connected to a resistor  341  that is used for a low voltage detection of the portable battery  31 . When the current of the portable battery  31  passes through the resistor  341 , the voltage of the portable battery  31  is regulated by the resistor  341 . Thus, when the voltage of the portable battery  31  is greater than a preset value (5.6V), the voltage of the portable battery  31  is regulated by the resistor  341  to the working voltage (ranged between 2.8V and 2.3V) of the control IC  34  even if the voltage of the portable battery  31  is disposed at a saturated value (8.4V). If not so, the control IC  34  will stop operating automatically. On the contrary, when the voltage of the portable battery  31  is lower than the preset value (5.6V), the voltage of the portable battery  31  cannot be regulated by the resistor  341  to the working voltage (ranged between 2.8V and 2.3V) of the control IC  34 , so that the control IC  34  will stop operating. 
     After the low voltage detection of the portable battery  31  is accomplished, the fourth leg  344  of the control IC  34  is connected to an impulse IC  342  which is provided with a transistor  3421  that is operated to control the on/off percentage of the duty cycle of the portable battery  31 . In such a manner, the temperature is preset when the portable battery  31  is started. Then, the control IC  34  of the controller  3  automatically detects the voltage variation of the portable battery  31 . Then, the transistor  3421  of the impulse IC  342  is driven by the fourth leg  344  of the control IC  34  to change the on/off percentage of the duty cycle of the portable battery  31  and to regulate the output current of the portable battery  31  according to the detected voltage variation of the portable battery  31 , so that the input current of the heating module  33  is kept at a constant value, and the temperature of the heating module  33  of the heating apparatus is kept at a constant value (the preset temperature) at any time. At the same time, the control IC  34  is connected to an indication unit  343  which is used to indicate the on/off percentage of the duty cycle of the portable battery  31 . 
     In the preferred embodiment of the present invention, the indication unit  343  is designed to indicate the on/off percentage of a four-step temperature. The indication unit  343  includes a first LED (light emitting diode)  3431  to indicate the on/off percentage (the on action of the output current is 25% and the off action of the output current is 75%) under the maximum temperature, a second LED  3432  to indicate the on/off percentage (the on action of the output current is 50% and the off action of the output current is 50%) under the higher temperature, a third LED  3433  to indicate the on/off percentage (the on action of the output current is 75% and the off action of the output current is 25%) under the lower temperature, and a fourth LED  3434  to indicate the on/off percentage (the on action of the output current is 100% and the off action of the output current is 0%) under the minimum temperature. For example, if the lower temperature is chosen, the third LED  3433  of the indication unit  343  is lighted. At this time, the third LED  3433  of the indication unit  343  is connected to the sixteenth leg  346  of the control IC  34  so that the on action of the output current is 75% and the off action of the output current is 25%. Thus, when the voltage of the portable battery  31  is steady, the on action of the output current is 75% and the off action of the output current is 25%. 
     At this time, the seventh leg  345  of the control IC  34  can detect the voltage variation of the portable battery  31  to randomly change the on/off percentage of the duty cycle of the portable battery  31  and to regulate the output current of the portable battery  31  according to the detected voltage variation of the portable battery  31 , so that the input current of the heating module  33  is kept at a constant value, and the temperature of the heating module  33  of the heating apparatus is kept at a constant value at any time even if the voltage of the portable battery  31  is changed at any time. 
     Referring to  FIG. 3  with reference to  FIGS. 1 and 2 , the output voltage (or current) of the portable battery  31  is decreased gradually when the discharging time is increased. The working voltage of the portable battery  31  is 3.7V, the saturated voltage of the portable battery  31  is 4.2V (greater than the working voltage), and the protection voltage of the portable battery  31  is 2.8V so that when the voltage of the portable battery  31  is lower than 2.8V, the controller  3  and the portable battery  31  stop working. Thus, when two portable batteries  31  are connected serially, the working voltage of the two portable batteries  31  is 7.4V, the saturated voltage of the two portable batteries  31  is 8.4V, and the protection voltage of the two portable batteries  31  is 5.6V. 
     As shown in  FIG. 3 , the output (or discharging) voltage of the portable battery  31  has the maximum value (8.4V) when the portable battery  31  is disposed at the saturated state, and is then decreased gradually when the discharging time is increased. In addition, the output current of the portable battery  31  is kept constant for a period of time at the working voltage (7.2V to 7.6V), and is then decreased rapidly to the protection voltage (5.6V), and the controller  3  and the portable battery  31  stop working at the protection voltage (5.6V). Thus, the output current of the portable battery  31  is decreased successively when the voltage of the portable battery  31  is decreased, so that the temperature is also decreased successively and cannot be kept at the preset value. 
     Referring to  FIG. 4  with reference to  FIGS. 1-3 , the output current of the portable battery  31  is controlled by actions of the on/off percentage of the duty cycle of the portable battery  31 . In the preferred embodiment of the present invention, the actions of the on/off percentage of the duty cycle of the portable battery  31  are performed by four steps. In the first step of the maximum temperature, the on action of the output current is 25% and the off action of the output current is 75%. In the second step of the higher temperature, the on action of the output current is 50% and the off action of the output current is 50%. In the third step of the lower temperature, the on action of the output current is 75% and the off action of the output current is 25%. In the fourth step of the minimum temperature, the on action of the output current is 100% and the off action of the output current is 0%. The controller  3  is provided with a software program that previously detects the voltage variation of the portable battery  31  to control the on/off percentage of the duty cycle of the portable battery  31 . 
     In such a manner, when the voltage of the portable battery  31  is greater than the working voltage, the percentage of the on action of the output current is decreased, and the percentage of the off action of the output current is increased to decrease the output current of the portable battery  31  so as to keep the temperature of the heating module  33  of the heating apparatus at a constant value, and when the voltage of the portable battery  31  is lower than the working voltage, the percentage of the on action of the output current is increased, and the percentage of the off action of the output current is decreased to increase the output current of the portable battery  31  so as to keep the temperature of the heating module  33  of the heating apparatus at a constant value (the preset temperature). 
     Thus, the controller  3  previously detects the voltage variation of the portable battery  31  to randomly change the on/off percentage of the duty cycle of the portable battery  31  and to regulate (decrease or increase) the output current of the portable battery  31  according to the detected voltage variation of the portable battery  31 , so that the input current of the heating module  33  is kept at a constant value, and the temperature of the heating module  33  of the heating apparatus is kept at a constant value (the preset temperature) at any time even if the voltage of the portable battery  31  is changed at any time. 
     In other word, when the portable battery  31  is disposed at the saturated state, the voltage of the portable battery  31  has the maximum value, the output current of the portable battery  31  has the maximum value, so that the temperature of the heating module  33  has the maximum value. Similarly, when the voltage of the portable battery  31  has the minimum value, the output current of the portable battery  31  has the minimum value, so that the temperature of the heating module  33  has the minimum value. In such a manner, when the portable battery  31  has a higher voltage (greater than the working voltage) and higher output current (that is, the heating module  33  has a higher temperature), the on action of the duty cycle of the portable battery  31  has a lower percentage, and the off action of the duty cycle of the portable battery  31  has a higher percentage. On the contrary, when the portable battery  31  has a lower voltage (smaller than the working voltage) and lower output current (that is, the heating module  33  has a lower temperature) during a period of time, the on action of the duty cycle of the portable battery  31  has a higher percentage, and the off action of the duty cycle of the portable battery  31  has a lower percentage. Thus, the controller  3  previously detects the voltage variation of the portable battery  31  to randomly change the on/off percentage of the duty cycle of the portable battery  31  and to regulate (decrease or increase) the output current of the portable battery  31  according to the detected voltage variation of the portable battery  31 , so that the input current of the heating module  33  is kept at a constant value, and the temperature of the heating module  33  is kept at a constant value (the preset temperature) at any time even if the voltage of the portable battery  31  is changed at any time. 
     An example is used to illustrate the variation of the voltage, current and power when using the heating process of the present invention. 
     In the preferred embodiment of the present invention, assuming 1) the load of the heating module  33  is 0.45 A (ampere), 2) the content of the portable battery  31  is 2200 mAh (millimeter ampere hour), 3) the working voltage of the portable battery  31  is 7.4V (volt) when two batteries are connected serially, 4) the resistance of the heating module  33  is 16.44Ω (ohm), and 5) the preset temperature is 50° C. (centigrade), the relation of the voltage (V), power (P), current (I) and resistance (R) is listed as follows according the formulas of P=I*V and I=V/R. 
     
       
         
           
               
               
               
               
               
             
               
                   
                   
               
               
                   
                 V 
                 P 
                 I 
                 R 
               
               
                   
                   
               
             
            
               
                   
                 8.4 
                 4.4 W 
                 0.525 A 
                 16.44 Ω 
               
               
                   
                 8.3 
                 4.3 W 
                 0.519 A 
                 16.44 Ω 
               
               
                   
                 . 
                 . 
                 . 
                 . 
               
               
                   
                 7.5 
                 3.42 W  
                 0.456 A 
                 16.44 Ω 
               
               
                   
                 7.4 
                 3.3 W 
                  0.45 A 
                 16.44 Ω 
               
               
                   
                 7.3 
                 3.2 W 
                 0.444 A 
                 16.44 Ω 
               
               
                   
                 . 
                 . 
                 . 
                 . 
               
               
                   
                 5.6 
                 1.9 W 
                  0.34 A 
                 16.44 Ω 
               
               
                   
                   
               
            
           
         
       
     
     Then, the on/off percentage of the duty cycle of the portable battery  31  is changed according to the voltage variation of the portable battery  31  and is listed in the following table. 
     
       
         
           
               
               
               
             
               
                   
               
               
                 V 
                 on 
                 off 
               
               
                   
               
             
            
               
                 8.4 V 
                 400/1000 
                 600/1000 
               
               
                 8.3 V 
                 435/1000 
                 565/1000 
               
               
                 . 
                 . 
                 . 
               
               
                 7.5 V 
                 715/1000 
                 285/1000 
               
               
                 7.4 V 
                 750/1000 
                 250/1000 
               
               
                 7.3 V 
                 785/1000 
                 215/1000 
               
               
                 . 
                 . 
                 . 
               
               
                 5.7 V 
                 960/1000 
                  40/1000 
               
               
                 5.6 V 
                 995/1000 
                  5/1000 
               
               
                   
               
            
           
         
       
     
     Thus, in the above table, the duty cycle of the portable battery  31  is 1000 times/second. For example, when the voltage of the portable battery  31  reaches 7.4V (the working voltage), the on action of the output current is 75% (750/1000) and the off action of the output current is 25% (250/1000). 
     Accordingly, the controller  3  previously detects the voltage variation of the portable battery  31  to randomly change the on/off percentage of the duty cycle of the portable battery  31  and to regulate (decrease or increase) the output current of the portable battery  31  according to the detected voltage variation of the portable battery  31 , so that the input current of the heating module  33  is kept at a constant value, and the temperature of the heating module  33  of the heating apparatus is kept at a constant value (the preset temperature) at any time even if the voltage of the portable battery  31  is changed at any time. 
     Although the invention has been explained in relation to its preferred embodiment(s) as mentioned above, it is to be understood that many other possible modifications and variations can be made without departing from the scope of the present invention. It is, therefore, contemplated that the appended claim or claims will cover such modifications and variations that fall within the true scope of the invention.