Abstract:
A heating device for an electric water heater, especially a heating device that can effectively recover waste heat, the device includes a secondary water box provided on one of the top and the bottom sides of a flat type main water box, the secondary water box is communicated with the main water box to guide water of the secondary water box into the main water box; the main and the secondary water boxes are provided therebetween with a laminate electric heating board of which the top and the bottom sides are clung respectively to the secondary water box and the main water box, an effect of preheating the water in the secondary water box is obtained to thereby effectively use the waste heat for saving energy source, and heating efficiency can be increased.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a heating device for an electric water heater, and especially to a heating device having a main water box and a secondary water box, also having an electric heating board for synchronically heating the main water box and the secondary water box. 
         [0003]    2. Description of the Prior Art 
         [0004]    In the present time, conventional electric water heaters include heat storing type water heaters and immediately heating type heaters; a heat storing type water heater mainly is used to store water in a main water box of a water heater, and uses a spiral-pipe type electric heating tube stored therein with tungsten wires to conduct heating; a conventional electric water heater has the following defects: the capacity of its main water box is limited, its speed of heating is slow, and thereby it is hard to sustainingly supply hot water for using of multiple people, and it needs to be sustainingly supplied with electric power to keep the temperature of water, hence it is electric power consumptive and can hardly have its heating efficiency increased. 
         [0005]    While an immediately heating type heater is installed at a hot water outlet port in a bathroom, in its structure, the electric heating tube stored therein with tungsten wires is installed in a heating cylinder of the heater, the heating cylinder is only a little larger than the electric heating tube, in order to form between the inner wall of the heating cylinder and the outside wall of the electric heating tube a narrow space for flowing through of water, for the benefit of reducing the time required for heating water to get a desired temperature, thereby to sustainingly supplying hot water for multiple people; however, such heater has the following defects: the capacity of the narrow space is limited, and the path for heating is short, if it needs to have water gotten its desired temperature, the flowing speed of water must be reduced, thereby hot water supplying becomes slow, and the efficient of heating is hard to be increased too. 
         [0006]    And more, when the electric heating tube heats the heating cylinder: after the water in the heating cylinder is heated, heat can be conducted to the outside area of the heating cylinder, and heat is scattered after the outside area of the heating cylinder touches cool air; namely, the energy source consumed during heating of the electric heating tube is not yet fully used, it results scattering of waste heat, this is not environmental conservative. 
         [0007]    Further, as to the mode of allocation of the above conventional electric heating tube (especially the spiral-pipe type electric heating tube which is dipped in water), after long period using, the surface of the electric heating tube will be adsorbed with water filth, so that the efficiency of heating and heat conducting of the electric heating tube become inferior, this in turn increases the electricity consumption and thus is not environmental conservative. 
         [0008]    In view of these, the inventor provides the present invention based on his experience of years in production electric water heaters and completes it with ingenious thought, delicate repeated thinking and testing for overcoming the above mentioned problems. 
       SUMMARY OF THE INVENTION 
       [0009]    The primary object of the present invention is to provide a heating device which can effectively recover wasting heat to overcome the above mentioned problems in the prior art including: the conventional electric water heater is hard to have its efficient of heating increased, hot water supplying becomes slow, the surface of the electric heating tube dipped in water is subject to having water filth to make the efficiency of heating and heat conducting of the electric heating tube become inferior; thereby electricity consumption amount can be reduced, and the hot water supplying amount can be increased. 
         [0010]    For achieving the above object, the electric water heater of the present invention includes: 
         [0011]    a main water box at least having a heat conducting surface, and having on its two ends respectively a water inlet port and a hot water supplying port; 
         [0012]    a secondary water box provided on one of the top and the bottom sides of the main water box, having a heat receiving surface, a water intake port and a water discharging port, the water discharging port is communicated with the water inlet port to guide the water of the secondary water box into the main water box; and 
         [0013]    an electric heating board provided between the main water box and the secondary water box, the top and the bottom sides of the electric heating board are clung respectively to a heat receiving surface of the secondary water box and a heat conducting surface of main water box, when one of the top and the bottom sides of the electric heating board heats the water in the main water box, the remaining heat induced on the other of the top and the bottom sides is conducted via the heat receiving surface to the secondary water box; the main water box, the electric heating board and the secondary water box are piled to form an integral unit. 
         [0014]    From the above stated, the water intake port of the secondary water box can be connected to an outside water source such as tap water to have the tap water flowed through the water intake port, the secondary water box, the water discharging port and the water inlet port and gotten into the main water box; in this period, the tap water is heated by the electric heating board for the first time heating in the secondary water box, then is heated by the electric heating board for the second time heating in the main water box, and is discharged through the water supplying port for use of a user. 
         [0015]    Thereby, the electric heating board is not dipped in water to get rid of the problem of adsorption of water filth to affect the efficiency of heating and heat conducting of the electric heating tube; and when one of the top and the bottom sides of the electric heating board gets heat energy to heat the water in the main water box, the heat created on the other one of the top and the bottom sides of the electric heating board can synchronically preheat the water in the secondary water box to thereby fully use the energy source consumed during heating of the electric heating boards, hence heating efficiency of the electric water heater on the water flow can be increased under the condition that the water flow is maintained at a normal flowing speed, and energy source can be saved to thereby meet the requirement of environmental conservation. 
         [0016]    In addition to the above stated, another electric water heater of the present invention includes: 
         [0017]    a main water box having a first heat conducting surface and a second heat conducting surface on the top and the bottom sides of it respectively, and having on its two ends respectively a water inlet port and a hot water supplying port; 
         [0018]    a first secondary water box provided on a bottom side of the main water box, having a first heat receiving surface, and having on its two ends respectively a first water intake port and a first water discharging port; 
         [0019]    a second secondary water box provided on a top side of the main water box, having a second heat receiving surface, and having on its two ends respectively a second water intake port and a second water discharging port, the first water discharging port is communicated with the second water intake port, while the second water discharging port is communicated with the water inlet port to guide the water of the first secondary water box into the main water box; 
         [0020]    a first electric heating board provided between the main water box and the first secondary water box, the top and the bottom sides of it are clung respectively to the first heat receiving surface of the first secondary water box and the first heat conducting surface of the main water box, when the topside of the first electric heating board heats the water in the main water box via the first heat conducting surface, the remaining heat induced on the bottom side is conducted via the first heat receiving surface to the first secondary water box; and 
         [0021]    a second electric heating board provided between the main water box and the second secondary water box, the top and the bottom sides of it are clung respectively to the second heat receiving surface of the second secondary water box and the second heat conducting surface of the main water box, when the bottom side of the second electric heating board heats the water in the main water box via the second heat receiving surface, the remaining heat induced on the top side is conducted via the second heat receiving surface to the second secondary water box; the first secondary water box, the first electric heating board, the main water box, the second electric heating board and the second secondary water box are piled to form an integral unit. 
         [0022]    From the above stated, the first water intake port of the first secondary water box can be connected to an outside water source such as tap water to have the tap water flowed through the first water intake port, the first secondary water box, the first water discharging port, the second water intake port, the second secondary water box, the second water discharging port and the water inlet port, and gotten into the main water box. 
         [0023]    In this period, the tap water is heated by the first electric heating board for the first time heating in the first secondary water box, then is heated by the second electric heating board for the second time heating in the second secondary water box, thereafter is heated simultaneously by the first and second electric heating boards for the third time heating in the main water box, and is discharged through the water supplying port for use of the user. 
         [0024]    Thereby, the first and second electric heating boards are not dipped in water to get rid of the problem of adsorption of water filth to affect the efficiency of heating and heat conducting; and when the heat energy created on the top side and the bottom side respectively of the first and second electric heating boards heats the water in the main water box, the heat energy created on the bottom side and the top side respectively of the first and second electric heating boards can synchronically preheat the water in the first and second secondary water boxes to thereby fully use the energy source consumed during heating of the first and second electric heating boards by the first and second electric heating boards, hence heating efficiency of the electric water heater on the water flow can be increased under the condition that the water flow is maintained at a normal flowing speed, and energy source can be saved to thereby meet the requirement of environmental conservation. 
         [0025]    The present invention is further described about its particular mode of practicing as below: 
         [0026]    The main water box is provided therein with a reciprocating revolving water channel communicated in-between the water inlet port and the hot water supplying port; in this way, water flow passing the water channel flows tortuously and thus is uniformly heated, and thereby increases the time for contacting and absorbing heat energy. 
         [0027]    The main water box has therein a plurality of parallelly spaced and alternately arranged heat conducting boards, hence the water channel is formed among the heat conducting boards; the heat conducting boards can be made of high heat conducting metals; otherwise, the heat conducting boards can be sealed and stored therein with materials for super conductors. 
         [0028]    The electric heating boards can be made of micro crystal glass material, alternately, they can be made of the materials of steel or aluminum; the electric heating boards are provided thereon each with a reciprocating revolving electric heating element. 
         [0029]    The volumes of the secondary water boxes are both smaller than that of the main water box, and the secondary water boxes are provided with laminate water channels communicated in-between the intake port and the water discharging port. 
         [0030]    In compared with the prior art, the design that the electric heating boards of the present invention each is provided on the top and the bottom sides of it with a main water box and a (two) secondary water boxe(s) can get rid of the problem induced by dipping of the electric heating boards in water to affect the efficiency of heating and heat conducting, and can effectively use wasting heat created by the electric heating boards to thereby save the energy source, and further can largely increase the path and area for heating of water, hence the heating efficiency of water can be increased under the condition that the water flow is maintained at a normal flowing speed without descending, thus an effect that energy source is saved can be obtained. 
         [0031]    The present invention will be adequately and definitely apparent after reading the detailed description of the preferred embodiments thereof in reference to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0032]      FIG. 1  is a perspective view of a preferred embodiment of the present invention; 
           [0033]      FIG. 2  is a perspective view showing the analytic details of the embodiment of  FIG. 1 ; 
           [0034]      FIG. 3  is an analytic perspective view showing a main water box in  FIG. 1 ; 
           [0035]      FIG. 4  is a front view of  FIG. 1 , 
           [0036]      FIG. 5  is a top view of  FIG. 4 ; 
           [0037]      FIG. 6  is a right side view of  FIG. 4 ; 
           [0038]      FIG. 7  is a left side view of  FIG. 4 ; 
           [0039]      FIG. 8  is a sectional view taken from the sectional line A-A in  FIG. 4 ; 
           [0040]      FIG. 9  is a sectional view taken from the sectional line B-B in  FIG. 4 ; 
           [0041]      FIG. 10  is a sectional view taken from the sectional line C-C in  FIG. 4 ; 
           [0042]      FIG. 11  is a top view of an electric heating board in  FIG. 2 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0043]    Referring to  FIG. 1  showing a perspective view of a preferred embodiment of the present invention, and simultaneously referring to  FIGS. 2 to 7  in order to specify the heating device for an electric water heater of the present invention, the heating device for an electric water heater includes a flat type main water box  5 , a laminate first secondary water box  1 , a laminate second secondary water box  2 , a laminate first electric heating board  3  and a laminate second electric heating board  4 . 
         [0044]    Wherein: the main water box  5  is in a rectangular shape, it has respectively on its top and bottom sides a heat conducting surface  53  facing to the lower direction, and a heat conducting surface  54  facing to the upper direction, and it has on its two ends respectively a water inlet port  51  and a hot water supplying port  52 ; the main water box  5  is provided therein with a reciprocating revolving water channel  50  (as shown in  FIG. 9 ) communicated in-between the water inlet port  51  and the hot water supplying port  52 ; the water channel  50  is located between the first electric heating board  53  and the second electric heating board  54 . 
         [0045]    The first secondary water box  1  is in a rectangular shape and is provided on a bottom side of the main water box  5  near the first electric heating board  53 , the first secondary water box  1  is provided on its top area with a first heat receiving surface  13  facing to the upper direction, and has on its two ends respectively a first water intake port  11  and a first water discharging port  12 ; the volume in the first secondary water box  1  is smaller than that of the inner space of the main water box  5 , and the internal of the first secondary water box  1  is formed to have a laminate water channel  10  (as shown in  FIG. 10 ) communicated in-between the first intake port  11  and the first water discharging port  12 , the water channel  10  is located at the bottom of the first heat receiving surface  13  of the first secondary water box  1 . 
         [0046]    The second secondary water box  2  is in a rectangular shape and is provided on a top side of the main water box  5  near the second electric heating board  54 , the second secondary water box  2  is provided on its bottom area with a second heat receiving surface  23  facing to the lower direction, and has on its two ends respectively a second water intake port  21  and a second water discharging port  22 ; the volume in the second secondary water box  2  is smaller than that of the inner space of the main water box  5 , and the internal of the second secondary water box  2  is formed to have a laminate water channel  20  (as shown in  FIG. 8 ) communicated in-between the second intake port  21  and the second water discharging port  22 , the water channel  20  is located at the top of the second heat receiving surface  23  of the second secondary water box  2 . 
         [0047]    The first water discharging port  12  and the second intake port  21  are mutually communicated via a water tube (not shown), the second water discharging port  22  and the water inlet port  51  are mutually communicated via another water tube (not shown), thereby water in the first secondary water box  1  can be guided through the second secondary water box  2  to enter the main water box  5 . 
         [0048]    The first electric heating board  3  is in a rectangular shape and is provided between the main water box  5  and the first secondary water box  1 , its top and bottom sides are clung respectively to the first heat receiving surface  13  of the first secondary water box  1  and the first heat conducting surface  53  of the main water box  5 , the first electric heating board  3  thus can synchronically heat the water in the first secondary water box  1  and the main water box  5 . 
         [0049]    The second electric heating board  4  is in a rectangular shape and is provided between the main water box  5  and the second secondary water box  2 , its top and bottom sides are clung respectively to the second heat receiving surface  23  of the second secondary water box  2  and the second heat conducting surface  54  of the main water box  5 , the second electric heating board  4  thus can synchronically heat the water in the second secondary water box  2  and the main water box  5 ; the first secondary water box  1 , the first electric heating board  3 , the main water box  5 , the second electric heating board  4  and the second secondary water box  2  are piled to form an integral unit. 
         [0050]    From the above stated, the first water intake port  11  of the first secondary water box  1  can be connected to an outside water source such as tap water to have the tap water flowed through the first water intake port  11 , the first secondary water box  1 , the first water discharging port  12 , the second water intake port  21 , the second secondary water box  2 , the second water discharging port  22  and the water inlet port  51 , and gotten into the main water box S. 
         [0051]    In this period, when the top side of the first electric heating board  3  heats the water in the main water box  5  via the first heat conducting surface  53 , the remaining heat induced on the bottom side is conducted via the first heat receiving surface  13  to the first secondary water box  1 ; and when the bottom side of the second electric heating board  4  heats the water in the main water box  5  via the second heat conducting surface  54 , the remaining heat induced on the top side is conducted via the second heat receiving surface  23  to the second secondary water box  2 . 
         [0052]    Thereby, the tap water is heated by the first electric heating board  3  for the first time heating in the first secondary water box  1 , then is heated by the second electric heating board  4  for the second time heating in the second secondary water box  2 , thereafter is heated simultaneously by the first and second electric heating boards  3 ,  4  for the third time heating in the main water box  5 , and is discharged through the water supplying port  52  for use of the user. 
         [0053]    One thing is worth mentioning, the laminate water channels  10 ,  20  of the first and the second secondary water boxes  1 ,  2  can increase the path and area for heating of water; and the first and second electric heating boards  3 ,  4  can directly heat the water channels  10 ,  20  in a fully covering mode through the first heat receiving surface  13  and the second heat receiving surface  23  to increase the heat exchanging efficiency of the first and second electric heating boards  3 ,  4 . 
         [0054]    And more, the reciprocating revolving water channel  50  of the main water box  5  can make the water flow proceed tortuously and thus be uniformly heated, and thereby increase the time for contacting and absorbing heat energy; and the first and second electric heating boards  3 ,  4  can together directly heat the water channel  50  in a fully covering mode through the first heat conducting surface  53  and the second heat conducting surface  54  to increase the heat exchanging efficiency of the first and second electric heating boards  3 ,  4 . 
         [0055]    And further, the first and the second secondary water boxes  1 ,  2 , the first and second electric heating boards  3 ,  4  and the main water box  5  are piled to form an integral unit; and the first and second electric heating boards  3 ,  4  are sandwiched in the integral unit, so that the heat energy of the first and second electric heating boards  3 ,  4  can be adequately used to prevent waste by scattering of the heat outwards; meantime the main water box  5  can get the function of heat preservation to thereby increase the heat exchanging efficiency of the first and second electric heating boards  3 ,  4 . 
         [0056]    Hence the first and second electric heating boards  3 ,  4  are not dipped in water to get rid of the problem of adsorption of water filth to affect the efficiency of heating and heat conducting; and when the top side and the bottom side respectively of the first and second electric heating boards  3 ,  4  get heat energy to heat the water in the main water box  5 , the remaining heat created on the bottom side and the top side respectively of the first and second electric heating boards  3 ,  4  can synchronically preheat the water in the first and second secondary water boxes  1 ,  2  to thereby fully use the energy source consumed during heating of the first and second electric heating boards  3 , 4 , hence the problems resided in the conventional water heaters stated in “Description of the Prior Art” that the efficient of heating is hard to be increased, hot water supplying becomes slow, the energy source consumed during heating of the electric heating tube is not fully used, and the surface of the electric heating tube dipped in water is subject to having water filth to make the efficiency of heating and heat conducting of the electric heating tube become inferior—can be overcome; hence heating efficiency of the electric water heater on the tap flow and the amount of water applying can be increased under the condition that the tap water flow is maintained at a normal flowing speed, and energy source can be saved to thereby meet the requirement of environmental conservation. 
         [0057]    The following is description about another particular mode of practicing of the present invention as below: 
         [0058]    In practicing, the above mentioned main water box  5  is provided therein with a plurality of parallelly spaced and alternately arranged heat conducting boards  55 , hence the water channel  50  is formed among the heat conducting boards  55 ; the heat conducting boards  55  can be made of high heat conducting metals; otherwise, the heat conducting boards  55  can be sealed and stored therein with materials for super conductors to thereby increase the heat exchanging efficiency of the first and second electric heating boards  3 ,  4 . 
         [0059]    And in practicing, the electric heating boards  3 ,  4  can be made of micro crystal glass material; alternately, they can be made of the materials of steel or aluminum; the electric heating boards  3 ,  4  are provided thereon each with a reciprocating revolving electric heating element  31  ( 41 ) as shown in  FIG. 11 , the electric heating elements  31 ,  41  practically can be made by using tungsten wires or electric heating tubes sealed therein with tungsten wires, to thereby increase the heat exchanging efficiency of the first and second electric heating boards  3 ,  4 . 
         [0060]    In addition to these, the present invention can also use a single electric heating board and a single secondary water box, for example, in the embodiment, there are a first secondary water box  1 , a first electric heating board  3  and the main water box  5 ; alternately, it can use a second secondary water box  2 , a second electric heating board  4  and the main water box  5 . The structural composition and the mode of practicing are similar to the above detailedly stated embodiment. 
         [0061]    In compared with the prior art, the design that the first and second electric heating boards  3 ,  4  of the present invention each is provided with a first and a second secondary water box  1  ( 2 ) and a main water box  5  can get rid of the problem induced by dipping of the electric heating boards in water to affect the efficiency of heating and heat conducting, and can effectively use wasting heat created by the first and the second electric heating board  3 ,  4  to thereby save the energy source, and further can largely increase the path and area for heating of water, hence the heating efficiency of water can be increased under the condition that the water flow is maintained at a normal flowing speed without descending. 
         [0062]    Accordingly, the description and the drawings given are only for illustrating the embodiment of the present invention, and not for giving any limitation to the scope of the present invention; it will be apparent to those skilled in this art that various equivalent modifications or changes without departing from the spirit of this invention shall also fall within the scope of the appended claims.