Abstract:
The present invention discloses an all disassembleable electric-heating apparatus comprising a shell, a cover, a reservoir installed inside said shell, an electric heater installed inside said reservoir and immersed in the liquid contents of said reservoir in working mode, and control elements including a control box and thermo-elements; wherein, said thermo-elements include electrical elements, said electrical elements are peripherically electric-insulated and sealed, so as to be immersed in the liquid contents of said reservoir in working mode and be taken out for cleaning after use.

Description:
TECHNICAL FIELD 
   This invention relates to an electric-heating apparatus of which almost all parts can be disassembled and cleaned. 
   BACKGROUND OF THE INVENTION 
   Currently, there exists in the market a so-called all disassembleable electric-heating apparatus, of which almost all parts can be disassembled and cleaned conveniently by the users. For example, there is an all disassembleable electric fryer, including a metal shell, a top cover, an oil reservoir, a basket assembly and electrical elements; wherein, said electrical elements comprise a control box, an electric heater, a thermo-control for regulating the oil temperature and a thermo-limitation for limiting the maximum oil temperature; and wherein, all of the metal shell, the top cover, the reservoir, the basket assembly and control elements can be taken out for cleaning. Since the electric heater with electric-insulating coating needs to be submersed in the oil, in order to control the oil temperature accurately, the thermo-control and the thermo-limitation should also be immersed in the oil and secured with the electric heater, therefore, the thermo-control and the thermo-limitation should have excellent electric resistance. To satisfy the above requirements, the existing all disassembleable electric fryer uses mechanical elements, i.e., the capillary thermo-elements, for regulating the oil temperature. Although the capillary thermo-elements have good electric resistance, they have following shortcomings: first, they are expensive, accounting for around 20% of the total production cost, which greatly affects the competitiveness of the products; secondly, the precision of the mechanical elements is poor, which causes considerable fluctuation of the oil temperature; thirdly, the capillary tube has very small radius and easy to be damaged when cleaning. The electrical thermo-elements, such as thermistors, fuses, etc., are capable of detecting and controlling the temperature, but due to the problem of non-electric insulation, they are not used in the all disassembleable electric-heating apparatus. 
   SUMMARY OF THE INVENTION 
   The main object of the present invention is to provide an all disassembleable electric-heating apparatus, using electrical thermo-elements in stead of expensive mechanical thermo-elements, which satisfies the requirements for electric insulation, lowers the production cost, improves the precision of temperature control, and is more convenient and reliable for the users. 
   According to the present invention, an all disassembleable electric-heating apparatus comprises:
         a shell;   a cover;   a reservoir installed inside said shell;   an electric heater installed inside said reservoir and immersed in the liquid contents of said reservoir in working mode;   control elements including a control box and thermo-elements; wherein, said thermo-elements include electrical elements, said electrical elements are peripherically electric-insulated and sealed, so as to be immersed in the liquid contents of said reservoir in working mode and be taken out for cleaning after use.       

   Said thermo-elements include thermo-controls for regulating the temperature and thermo-limitations for limiting the maximum temperature. 
   Said thermo-control may be a thermistor, said thermistor and the leads thereof are incased in a sealing tube. 
   With the thermistor secured inside the sealing tube, the thermistor can be used in an all disassembleable electric-heating apparatus instead of the capillary thermo-elements, having the same function, therefore, the production cost can be greatly reduced. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an explosive diagram of an all disassembleable electric fryer according to one embodiment of the present invention; 
       FIG. 2  shows the location of the thermo-control and the thermo-limitation according to embodiment 1 of the all disassembleable electric fryer as shown in  FIG. 1 ; 
       FIG. 3  shows the location of the thermo-control and the thermo-limitation according to embodiment 2 of the all disassembleable electric fryer as shown in  FIG. 1 ; 
       FIG. 4  shows alternative locations of the thermo-control and the thermo-limitation according to embodiment 2 of the all disassembleable electric fryer as shown in  FIG. 1 ; 
       FIG. 5  is an enlarged view showing the intra-tube arrangement of the thermo-elements shown in  FIG. 2 ; 
       FIG. 6  is an enlarged view showing an alternative intra-tube arrangement of the thermo-elements shown in  FIG. 2 ; 
       FIG. 7  shows the locations of the thermo-control and the thermo-limitation according to embodiment 3 of the all disassembleable electric fryer as shown in  FIG. 1 ; 
       FIG. 8  shows the locations of the thermo-control and the thermo-limitation according to embodiment 4 of the all disassembleable electric fryer as shown in  FIG. 1 ; 
       FIG. 9   a  is a front view of the tube accommodating the thermo-elements shown in  FIG. 2 ; 
       FIG. 9   b  is a top view of the tube as shown in  FIG. 9   a;    
       FIG. 10  is a schematic diagram of a restorable thermo-limitation; 
       FIG. 11  is the electro-circuit diagram of the all disassembleable electric fryer as shown in  FIG. 1 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The present invention may apply to various all disassembleable electric-heating apparatus, e.g. an all disassembleable electric fryer, a coffee maker, a water heater, an electro-thermal producer, etc. 
   As shown in  FIG. 1 , the all disassembleable electric fryer includes a shell  1 , a top cover  2 , an oil reservoir  3 , a basket assembly  4  and a control component  5 . Said shell  1  has two handles, each located respectively at one of the two opposite sidewalls. The lower edge of all of the four sidewalls of the shell  1  is vertically inturned and forms a narrow rim  11 , on which the whole electric fryer can stand stably. The reservoir  3  is held inside the shell  1 , and the upper edge of the reservoir  3  is bordered with an outturned rim  31  for resting the reservoir  3  over the shell  1  and lifting it up. The control component  5  comprises a control box  51 , an electric heater  6  and thermo-elements  52 , said thermo-elements  52  further include a thermo-control for controlling the oil temperature and a thermo-limitation for limiting the maximum oil temperature. The electric heater  6  with insulating coatings is immersed in the oil in working mode, the leads of which are connected with the control box  51 , while the thermo-elements  52  are also immersed in the oil and secured with the electric heater  6 , the leads of which are also connected with the control box  51 . The basket assembly  4  is equipped with a handle for securing and carrying the basket assembly  4 . The basket  41  of the basket assembly  4  positioned over the electric heater  6  and the thermo-elements  52  is also submersible in the oil, accommodating the food being cooked. When said electric fryer is to be cleaned after use, the user may open the top cover  2 , take out the basket assembly  4 , the control component  5  and the reservoir  3  in turn. All elements, except the control box, can be washed with water. 
   Embodiment 1 
   As shown in  FIG. 2 , the invention is featured with the locations of the thermo-control and the thermo-limitation. 
   In the present embodiment, the thermo-control uses a thermistor  521 , the thermo-limitation uses a fuse  522 , both of the thermistor  521  and the fuse  522  are incased in the same tube  8 , which may be the same stainless steel tube as the housing tube of the electric heater  6 . As shown in  FIG. 9   a , seen from the front, the tube  8  is of “           ” shape, the left upper end of which is connected to the control box  51 , the right lower end of which is sealed, i.e., the outlet of the tube is first narrowed into conical shape, then the end of the conical tube is sealed by welding. In addition, the tube  8  is flatten somewhere along the tube so as to secure the leads inside the tube. As shown in  FIG. 9   b , seen from the top, the tube  8  is bent into “         ” shape. Actually, the shape of the tube  8  is determined according to the locations of the thermo-elements  52 . In the present embodiment, the conical tube  82  of the tube  8  is positioned between the tubes of the electric heater  6 , and is coplanar with the electric heater  6 . The thermo-elements  52  are installed within the end part of the tube  8 , which is secured by a frame  7  with the electric heater  6  immersed in the oil.
   To ensure the electric insulation of the thermo-control and the thermo-limitation, the thermistor  521  and the fuse  522  can be arranged as shown in  FIG. 5 : there are insulating coatings at the peripheries of the thermistor  521 , fuse  522  and the leads, and the thermistor  521  and the fuse  522  are secured inside the tube  8 , either contacting or non-contacting the tube-walls. An alternative arrangement of the thermistor  521  and fuse  522  is shown as  FIG. 6 : the thermistor  521 , the fuse  522  and the leads are first inserted into the fluoride resin tube  9 , which is a heat and electric resistant tube, then the tube  9  enclosed with the thermistor  521  and the fuse  522  is installed inside the tube  8 . 
   As shown in  FIG. 11 , the electro-circuit of the present invention is the same as the prior art, except that the thermo-elements use the electrical elements instead of mechanical elements: the thermistor RT is used to detect the change of the oil temperature. The objective oil temperature is set by two alternative ways: one way is by changing the resistance of the variable resistor VR 19 ; the other way is by switching the 6-way switch so as to select a different resistance R 13 , or R 14 , or R 7 , or R 8 , or R 9 , or R 10 . The single-chip U 1  (e.g., F9444) compares the actual oil temperature detected by the thermistor RT with the objective oil temperature, then controls the RELAY  1  to be connected or disconnected, and to actuate the executor, electric heater (e.g., 1650W). If the actual oil temperature is equal to or greater than the objective oil temperature, the single-chip U 1  controls the RELAY  1  to be disconnected, the electric heater then stops heating; if the actual oil temperature is less than the objective oil temperature, the single-chip U 1  controls the RELAY  1  to be connected, the electric heater then starts heating. 
   When the reservoir  3  is dry-heating, since the thermistor  521  is secured near the electric heater  6 , it will soon sense the heat, and the electro-circuit is disconnected. Thus, the fuse  522  will be protected from being disconnected in case of dry heating. However, when the thermo-control is in short circuit, the fuse will be disconnected due to the gradual increase of the temperature. 
   Embodiment 2 
   As shown in  FIGS. 3 and 4 , the difference of the present embodiment compared with embodiment 1 is: the thermistor  521  and the fuse  522  are installed respectively inside different tubes. The tube  8   a  enclosed with the thermistor  521  remains secured near the electric heater with a frame  7   a , while the fuse  522  is secured inside another tube  8   b . The other ends of the tube  8   a  and  8   b  are connected with the control box  51 . The thermistor  521  and the fuse  522  can be installed at different locations, therefore, the bending shape of the tube  8   a  or  8   b  changes accordingly. 
   Embodiment 3 
   As shown in  FIG. 7 , the difference of the present embodiment compared with embodiment 2 is: a restorable thermo-control is used as the overheat protection element, e.g., the restorable disc-shaped thermo-control  523 . The function of said restorable thermo-control is similar to a fuse, except that, this thermo-control can be restored manually. 
   Its structure is as follows: The restorable disc-shaped thermo-control  523  is coated with an insulating material and is incased in a shell  101 , which is connected with the tube  8   c , the other end of the tube  8   c  is connected with the control box  51 . The two leads  102  of the restorable disc-shaped thermo-control  523  are connected with the internal elements of the control box  51  via the tube  8   c . The restore switch  103  of the restorable disc-shaped thermo-control  523  faces the connection point of the shell  101  and the tube  8   c , the lever  104  passes through the inner chamber of tube  8   c , the end of the lever  104  is positioned above the restore switch  103 , and the head of the lever  104  extends through the connection point of the tube  8   c  and the control box  51 . The temperature regulation process of the thermistor  521  is the same as that in embodiment 1 and 2, except for the temperature limitation: when the restorable thermo-control  523  is actuated due to overheat of the oil temperature or error of the electro-circuit, by pressing the lever  104 , the restore switch  103  can be restored, and thus the restorable disc-shaped thermo-control  523  is reset for continuous work. 
   Embodiment 4 
   In this embodiment, the mechanical capillary thermo-control  524  is used as the thermo-limitation as in the prior art, except that, the electrical element is used as the thermo-control. If a thermistor is used to control the oil temperature, the requirements for the location of the thermo-control is the same as those in embodiment 1, and the actual location can be adjust flexibly.