JP4987798B2 - Heating equipment - Google Patents

Description

  The present invention relates to a heating device such as an electric pot, a humidifier, and a rice cooker.

  This type of heating device includes a container that accommodates an object to be heated, and a heater is disposed as a heating unit in the container to heat the object to be heated via the container. Specifically, in an electric pot, water is accommodated as an object to be heated in a container, and the heater is operated to boil the water and keep it at a predetermined temperature. In the humidifier, water is accommodated as an object to be heated inside the container, and the heater is operated to boil the water and supply the steam to the room to humidify the room. In a rice cooker, rice and water are housed as objects to be heated inside a detachable container (pot), and the water is boiled by setting the container in the housing part (container) of the main body and operating the heater. Cook rice.

In this heating apparatus, one in which two or more heaters are connected in parallel is provided. Specifically, in this heating device, both ends of the nichrome wire of each heater are connected to a common electrode, and a switching circuit is provided between the common electrode and a power source. Then, the microcomputer is configured to detect the presence or absence of disconnection of each heater by comparing the combined resistance of the nichrome wire in a normal state with the combined resistance of one or a plurality of disconnected wires.
Japanese Patent Laid-Open No. 11-149973

  However, in the heating device described in Patent Document 1, since it is necessary to detect the combined resistance of the heater by a microcomputer, it is necessary to make a significant design change in the control board itself as well as the microcomputer control program. Moreover, in this patent document 1, even if some heaters are disconnected, the heating control is continued with other heaters, but in this case, a heating time longer than normal (when no disconnection) is required. Therefore, the area around the non-disconnected heater is abnormally heated. As a result, the surrounding resin parts may be melted.

  The present invention has been made in view of the conventional problems, and it is possible to detect the disconnection of the heater with the existing configuration without changing the design of the control board, and it is possible to reliably generate a further problem in the disconnection occurrence state. It is an object of the present invention to provide a heating device that can be prevented.

In order to solve the above-described problem, the heating device of the present invention includes two or more heaters connected in parallel to a container that accommodates an object to be heated, and a temperature detection unit that detects the temperature of the object to be heated via the container. In the heating apparatus that heats the object to be heated by controlling the heater based on the temperature detected by the temperature detecting means, the temperature detecting means detects when the heater is energized in a disconnected state. A determination value is set in advance based on a temperature increase gradient according to a value and a temperature increase gradient based on a detection value of the temperature detecting means when the heater is energized in a state where any of the heaters is disconnected, and heating operation by the heater Sometimes, it is configured to execute a disconnection determination step of determining that any heater is disconnected depending on whether or not the determination value is exceeded within a predetermined time.

  Here, “a state in which all the heaters are energized” refers to a heating device in which a boiling heater that is operated at the time of boiling processing and a thermal insulation heater that is operated at the time of thermal insulation processing are distinguished, such as an electric pot. , All boiling heaters or all warming heaters are contemplated.

  According to this heating apparatus, since the presence or absence of the disconnection of the heater is determined based on the detection value of the existing temperature detection means and the predetermined determination value, it is not necessary to change the design of the control board. Therefore, it can be realized inexpensively and easily.

And the heating apparatus of 1st invention is made to complete | finish this disconnection determination process, if the temperature detected by the said temperature detection means falls at the time of execution of the said disconnection determination process. Therefore, for example, when the user performs water addition in a plurality of times, it is possible to prevent erroneous determination that the heater is disconnected.

In the heating device according to the second aspect of the present invention, the disconnection determining step is started after a predetermined delay time from the execution of the heating operation by the heater, and the temperature detection means measures the temperature during the delay time measurement. When a drop in the level is detected, the measurement time is cleared and the measurement is performed again. Therefore, for example, when the user performs water addition in a plurality of times, the presence or absence of disconnection can be reliably detected in the disconnection determination step.

In these heating devices, a non-volatile storage means for storing the abnormality determination result in the disconnection determination step is provided, and if the abnormality determination is more than a predetermined number of times, the heating operation by the heater is not executable. Is preferred. In this way, since the heating operation is not performed even for a short time, it is possible to reliably prevent further abnormality from occurring.

  In the heating apparatus according to the present invention, since the presence or absence of a break in the heater is determined based on the detection value of the existing temperature detection means and the predetermined determination value, it is not necessary to change the design of the control board. If it is determined that the heater is disconnected, the heating operation is stopped, so that it is possible to prevent problems such as melting of surrounding resin parts.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows an electric pot that is a heating device according to an embodiment of the present invention. In this electric pot, a container 22 for containing water to be heated is disposed inside the outer package 10, and the water in the container 22 is heated by a plurality of boiling heaters 35, 44, and the hot water supply pump 26 is turned on. By operating it, hot water is discharged from the discharge part 30 through the pumping pipe 28.

  The exterior body 10 includes a cylindrical body 11, a shoulder body 17 attached to an upper portion of the body 11, and a lid body 21 attached to the shoulder body 17 so as to be opened and closed.

  The body 11 is provided with a nose portion 12 projecting outward on the front surface, and a discharge opening portion 13 opened downward near the tip. Further, the lower end opening of the body 11 is closed by the lower plate 14. Further, a rectangular opening 15 is provided on the front side of the body 11, and a transparent window member 16 capable of seeing through the inside is disposed in the opening 15.

  The shoulder body 17 has a lower end shape that coincides with the upper end opening of the body 11, and a hinge connection portion 18 for attaching the lid body 21 so as to be detachable and rotatable is provided on the back side thereof. The shoulder body 17 has a shape in which a portion located above the nose portion 12 is curved downward toward the tip, and an operation panel portion 19 is provided at that portion. On the back side of the operation panel portion 19, a lid disposing portion 20 that is recessed downward is provided, and an opening (not shown) that exposes the inside of the container 22 is provided in the lid disposing portion 20. .

  The lid body 21 has the same shape as the lid arrangement portion 20 of the shoulder body 17 and is pivotally attached to the hinge connection portion 18 so as to seal the upper end opening of the container 22 so as to be opened and closed. The lid body 21 is provided with an operation member (not shown) that is locked to the shoulder body 17 so as not to be opened and is unlocked by an opening operation.

  The container 22 is made of metal (stainless steel (SUS436L)) including a cylindrical container body 23 attached to the opening of the shoulder body 17 and a container bottom body 24 that closes the lower end opening of the container body 23. It is. The container bottom body 24 is provided with a connection hole 25 for connecting a hot water supply pump 26. The hot water supply pump 26 is connected to a pumping pipe 28 located behind the window member 16 via a joint member 27 having a substantially L shape. And the valve set 29 for preventing the water leakage at the time of a fall is connected to the upper end of this pumping pipe 28, and the discharge part 30 arrange | positioned in the discharge opening part 13 is provided in this valve set 29. . Further, the container 22 is provided with a heater mounting portion 31 that is recessed upward toward the inside of the container 22 at a position excluding the connection hole 25 in the container bottom body 24, and further has a circular shape at the center of the heater mounting portion 31. Thus, a sensor arrangement portion 32 that is recessed upward is provided.

  A bottom heater unit 34 for boiling and keeping the water stored in the container 22 is disposed on the heater mounting portion 31 of the container 22 so as not to be detached by the covering member 33. In the container 22 of this embodiment, a body heater unit 43 is disposed at the lower end of the container body 23 that is the outer peripheral portion.

  As shown in FIG. 2, the bottom heater unit 34 includes a bottom boiling heater 35, a bottom heat retaining heater 36, an insulating plate 39 that insulates between the heaters 35 and 36, and both ends, and a heater in which these are stacked inside. And a cover 40. The bottom boiling heater 35 is operated (energized) during the boiling process, and can output 905 W, for example. The bottom heat retaining heater 36 is operated during the heat retaining process, and can output 65 W, for example. The heaters 35 and 36 are obtained by winding a nichrome wire 38 around a mica plate 37 having a through hole 37a in the center. The insulating plate 39 is a mica plate having a through hole 39a at the center. The heater cover 40 is made of metal (aluminum) and serves as a heat radiating plate that averages the heat generated by the internal heaters 35 and 36 and supplies the heat to the container bottom 24, and has a shape slightly smaller than the heater mounting portion 31. A base plate portion 41 is formed, and three bent plate portions 42a, 42b, and 42c that are substantially the same shape as the base plate portion 41 by bending are provided.

  As shown in FIG. 3, the body heater unit 43 includes a body boiling heater 44 having a rectangular (band) shape, a holding frame 47 having a C shape in plan view, and a protective member 51 that protects the body boiling heater 44. It has. The body boiling heater 44 is operated at the time of boiling processing, and can output 295 W so as to be 1200 W together with the bottom boiling heater 35, for example. The body boiling heater 44 is obtained by winding a nichrome wire 46 so as to form a spiral with respect to a mica plate 45 having a plate shape. The holding frame 47 is made of metal (aluminum) and serves as a heat radiating plate, and has a substantially C-shaped cross section including an inner surface portion 48, an outer surface upper frame portion 49, and an outer surface lower frame portion 50. The protection member 51 is made of metal (iron) and has a diameter slightly smaller than the outer shape of the container body 23. At both ends of the protective member 51, tightened portions 52 that protrude outward are provided. The to-be-tightened portion 52 is used to fasten the body boiling heater 44 and the holding frame 47 located on the inner side to the container body 23 by being tightened with a fastening bracket (not shown). The protective member 51 is provided with an exposure hole 53 that exposes the connecting portion 46a of the body boiling heater 44 located inside.

  In the electric pot, as shown in FIG. 1, a thermistor 54 that is a temperature detecting means for detecting the water temperature inside through the container 22 passes through the bottom heater unit 34 and contacts the sensor arrangement portion 32. It is arranged to do. Further, a bottom heat shielding member 55 is disposed between the container 22 and the bottom of the exterior body 10 so as to cover the bottom of the container 22 so as to block heat of the bottom heater unit 34 with respect to the control board case 56. It is composed. Further, between the container 22 and the side portion of the exterior body 10, a body heat shield member 57 is disposed so as to cover the container body 23, and the heat of the body heater unit 43 with respect to a nearby resin product such as the pumping pipe 28. Is configured to shut off.

  The operation panel unit 19 formed on the upper outer surface of the nose unit 12 includes a plurality of switches 59, 60, 62, 63 and a plurality of display units 65-69, as shown in FIG. It is mounted on an operation board 58 located on the back of the operation panel unit 19. The operation board 58 is connected to a control board 70 described later.

  Specifically, a hot water supply switch 59 for operating the hot water supply pump 26 is provided in the center of the operation panel unit 19. A lock release switch 60 for permitting the operation of the hot water supply pump 26 is provided on the right side of the hot water supply switch 59. A heat retention selection switch 62 is provided below the hot water supply switch 59 to select the heat retention temperature as 90 ° C., 80 ° C., or off (no heat retention). Furthermore, a reboiling switch 63 for reboiling water in the container 22 is provided on the left side of the hot water supply switch 59. The lock release switch 60 of the present embodiment also serves as a discharge amount selection switch for selecting whether to supply hot water with a normal discharge amount or with a drip discharge amount smaller than normal. Specifically, the hot water supply process can be performed by operating the hot water supply switch 59 with a normal discharge amount by the first operation. Further, by the second operation, hot water supply processing can be performed with the drip discharge amount while maintaining the hot water supply possible state. Thereafter, the normal and the drip are sequentially changed for each operation.

  In addition, a drip display portion 65 is provided above the lock release switch 60 to indicate that the drip discharge amount is selected. Further, a 90 ° C. display unit 66 indicating that the 90 ° C. heat retention is selected is provided on the left side of the heat retention selection switch 62, and 80 ° C. indicating that the 80 ° C. heat retention is selected in the lower part thereof. A display unit 67 is provided. Furthermore, a cut-off display section 68 is provided on the right side of the heat retention selection switch 62 to indicate that the heat retention cut is selected. A re-boiling display unit 69 indicating that the re-boiling process is being executed is provided above the re-boiling switch 63. In addition, each of these display parts 65-69 are comprised by LED.

  In the electric pot, a control board 70 including a power supply unit is disposed in a control board case 56, and a microcomputer 71 which is a control means mounted on the control board 70 is used in accordance with a program stored in advance in a ROM 72 which is a storage means. A boiling process, a reboiling process, and a heat retention process are performed. And in this embodiment, it is set as the structure which performs the disconnection judgment process which detects the presence or absence of disconnection of the boiling heaters 35 and 44 at the time of a boiling process.

  Specifically, the boiling process is executed when the user connects a power cord to a commercial power source or when the user detects a temperature drop of 10 ° C. or more by adding water during the heat retaining process. . In this boiling process, the boiling heaters 35 and 44 connected in parallel via the relay 73 serving as switching means are operated to heat the water in the container 22, and the hot water temperature reaches a preset heating off temperature (98 ° C.). Rises, the boiling heaters 35 and 44 are turned off. Note that when the heating off temperature is 100 ° C., there is a situation where it cannot be detected due to the difference in altitude at the place of use, and there is a possibility that bump boiling may occur due to the residual heat of the boiling heaters 35, 44. is doing.

  The reboiling process is executed when the user operates the reboiling switch 63 of the operation panel unit 19. In this re-boiling process, as in the boiling process, the boiling heaters 35 and 44 are operated to heat the water in the container 22, and when the hot water temperature rises to a preset heating-off temperature, the boiling heaters 35 and 44 are turned on. It is to turn off.

  The heat retention process is subsequently performed when the boiling process or the reboiling process is completed. In this warming process, the bottom warming heater 36 is on / off controlled based on the temperature detected by the thermistor 54 so that the warming temperature set by the user by operating the warming selection switch 62 is maintained.

  In the disconnection determination step, the presence or absence of disconnection of the bottom boiling heater 35 and the trunk boiling heater 44 having different rated powers connected in parallel via the relay 73 is determined based on the temperature detected by the thermistor 54. Specifically, in the ROM 72, the temperature rise gradient of the detected temperature detected by the thermistor 54 in a state where all the boiling heaters 35, 44 are energized (non-disconnected state), and predetermined boiling heaters 35, 44 are intended. The determination value Th is set (stored) in advance on the basis of the temperature rise gradient of the detected temperature detected by the thermistor 54 in the state of being disconnected (disconnected state). Then, after the heating (boiling) operation by the boiling heaters 35 and 44 is started, the temperature is detected by the thermistor 54 with a predetermined delay time, and the boiling heaters 35 and 44 are determined depending on whether or not the determination value Th is exceeded within the predetermined time. It is configured to determine whether or not is disconnected.

  Here, a method for setting the determination value Th will be described in detail. First, the conditions for performing the boiling process are, as described above, when power is turned on and when a temperature drop of 10 ° C. or more occurs due to the addition of water. The time required for adding water has an error depending on the user, and the value detected by the thermistor 54 also decreases with a delay. Therefore, the determination (detection) start by the thermistor 54 is started after a predetermined delay time (for example, 5 seconds) has elapsed after the heating by the boiling heaters 35 and 44 is started. In addition, if one of the boiling heaters 35 and 44 is disconnected, performing a heating operation for a long time may affect the surrounding resin parts, so the determination time (abnormality detection time) is as short as possible (for example, 10 seconds). Furthermore, the temperature increase gradient based on the detection value of the thermistor 54 varies depending on the power supply environment in which the boiling process is performed and the indoor environment as well as the amount of water stored in the container 22. Therefore, the judgment value Th is raised under conditions where the boiling heaters 35 and 44 are in a normal undisconnected state and the rate of increase in the water temperature is the worst (for example, an input voltage of 90%, an indoor temperature of 5 ° C., a full amount of water (1500 ml)) Conditions with the best rate of increase in water temperature (for example, input voltage 110%, indoor temperature 30 ° C., water volume) at a possible temperature and in a state where any of the boiling heaters 35, 44 (for example, the bottom boiling heater 35) is disconnected. The temperature is set to a temperature at which the temperature cannot be raised with a small amount (400 ml) (3 ° C. in this embodiment).

  In the boiling process, when a temperature increase equal to or higher than the determination value Th is detected within the determination time, it is determined that neither of the boiling heaters 35 and 44 is in a normal state, and the boiling process is continued. If no temperature rise equal to or greater than the determination value Th is detected within the determination time, it is determined that one of the boiling heaters 35, 44 is in an abnormal state, the boiling process is stopped, and an abnormality notification step is performed. Execute. In addition, the abnormality alerting | reporting process of this embodiment combines the 90 degreeC display part 66, the 80 degreeC display part 67, the cut-off display part 68, and the reboiling display part 69 among the existing display parts 65-69, and is 90 degreeC. The display unit 66, the 80 ° C. display unit 67, the cut-off display unit 68, and the reboiling display unit 69 are configured to blink alternately.

  When disconnection of any of the boiling heaters 35 and 44 is detected in the disconnection determination step, the abnormality determination result is stored in the EEPROM 74 which is a nonvolatile storage means. If the abnormality determination is made a predetermined number of times (two times in the present embodiment) at the start of the boiling process (when power is turned on), all the heating operations, that is, the boiling process, the reboiling process, and the heat retaining process are performed. Infeasible.

  Furthermore, the user's work of adding water may be performed in multiple steps. For example, when the electric pot is installed in a place away from the sink and when water is carried into the container 22 having a small capacity, water is added during the abnormality determination process, and the water temperature does not rise ( May fall). Therefore, when the detection value by the thermistor 54 is reduced (for example, 1 ° C.) during the abnormality determination process, the disconnection determination process is terminated.

  Next, the control by the microcomputer 71 will be specifically described.

  First, when the user turns on the power by connecting the power cord to the commercial power source, as shown in FIG. 5, the microcomputer 71 reads the EEPROM 74 in step S1, and the abnormality determination number n is 2 (times). Detect whether or not there is. If the abnormality determination number n is not 2, the process proceeds to step S2. If the abnormality determination number n is 2, the process proceeds to step S12.

  In step S2, by outputting a signal to turn on the relay 73, the bottom boiling heater 35 and the trunk boiling heater 44 are turned on, and then in step S3, the delay timer (5 seconds) is reset and started. In step S4, the process waits until the delay timer counts up. When the delay timer counts up, the process proceeds to step S5.

  In step S5, after performing a disconnection determination step described later, it is detected whether or not a flag f indicating whether or not it is determined in step S6 that it is disconnected is 1 (0). If f is 0 (non-disconnection determination), the process proceeds to step S7. If f is 1 (disconnection determination), the process proceeds to step S10.

  In step S7, the process waits until the thermistor 54 detects that the liquid in the container 22 has been heated to the boiling temperature (98 ° C.). When the temperature is raised to the boiling temperature, the process proceeds to step S8. Next, in step S8, after performing the heat retention process according to the heat retention setting selected by the user, in step S9, the thermistor 54 detects whether or not the water temperature in the container 22 has been lowered to the heating start temperature at which the boiling process is performed. . If a temperature drop to the heating start temperature is detected, the process returns to step S1, and if a temperature drop to the heating start temperature is not detected, the process returns to step S8.

  On the other hand, in step S10, a signal is output so as to turn off the relay 73, thereby turning off the boiling heaters 35 and 44. Then, in step S11, 1 is added to the abnormality determination number n of the EEPROM 74. Thereafter, in step S12, the abnormality notification process is executed by the display units 66 to 69, and all the controls are finished. If the abnormality determination number n is 2 in step S1 immediately after the power is turned on, the abnormality notification is performed as it is without operating (turning on) the boiling heaters 35 and 44 by proceeding to step S12. Execute the process and finish.

  Next, the disconnection determination process in step S5 will be specifically described.

  In this disconnection determination step, as shown in FIG. 6, the microcomputer 71 detects the initial water temperature T0 in the container 22 by the thermistor 54 in step S5-1, and then in step S5-2, an abnormality detection timer (60 seconds). ) Is reset and started.

  Next, in step S5-3, the thermistor 54 again detects the water temperature Tn in the container 22, and then in step S5-4, the water temperature is equal to or higher than the set temperature (1 ° C.) compared with the water temperature Tn-1 detected immediately before. Determine whether it has fallen or not. If the water temperature has not dropped below the set temperature, the process proceeds to step S5-5. If the water temperature has dropped below the set temperature, the process proceeds to step S5-9.

  In step S5-5, it is detected whether or not the abnormality detection timer has counted up. If the abnormality detection timer has counted up, the process proceeds to step S5-6, and if not counted up, the process returns to step S5-3.

  In step S5-6, it is detected whether or not the temperature difference between the water temperature Tn detected last and the comparison reference temperature T0 detected first is equal to or greater than the determination value Th. If the temperature difference is less than the determination value (Tn−T0 <Th), it is determined that one of the boiling heaters 35, 44 is disconnected, and the process proceeds to step S5-7, where the disconnection determination flag f is set. Enter 1 and return. If the temperature difference is equal to or greater than the determination value (Tn−T0 ≧ Th), it is determined that neither of the boiling heaters 35 and 44 is disconnected, the process proceeds to step S5-8, and the disconnection determination flag f is set to 0. Enter and return.

  On the other hand, if it is detected in step S5-4 that the water temperature in the container 22 has decreased, the abnormality detection timer is stopped in step S5-9, and the process proceeds to step S5-8. Thus, when returning to the main flow, the normal boiling process is continued.

  As described above, in the electric pot of the present embodiment, since the presence or absence of disconnection of the boiling heaters 35 and 44 is determined based on the detection value of the existing thermistor 54 and the preset determination value Th, No design changes are required. Therefore, it can be realized inexpensively and easily. And this structure is the state where the boiling heater 35 with high rated power is disconnected in the state where the bottom boiling heater 35 and the trunk boiling heater 44 with different rated power are applied as in this embodiment. The state can be detected reliably.

  In addition, when it is determined that any of the boiling heaters 35 and 44 is disconnected in the disconnection determination step, the heating operation by the boiling heaters 35 and 44 is stopped, and thus heating is continued in an abnormal state. It is possible to prevent problems such as melting of surrounding resin parts. Moreover, since the abnormal state is displayed on the display units 66 to 69, the user can be surely notified of the abnormal state. In addition, when the abnormality determination is more than a predetermined number of times, the heating operation (boiling process) by the boiling heaters 35 and 44 cannot be performed, so that further abnormality due to the heating operation occurring even in a short time. It can be surely prevented.

  Furthermore, in the case of an electric pot, the boiling process is executed by the user adding water, and immediately after that, the temperature detected by the thermistor 54 is lowered, so that an accurate abnormality determination cannot be made. However, in the present embodiment, since the disconnection determination step is executed after a predetermined delay time, it is possible to reliably detect the presence or absence of disconnection. In addition, when the user adds water several times, the water temperature does not rise, so there is a possibility that it is determined that the boiling heaters 35 and 44 are disconnected even though they are not disconnected. . However, in this embodiment, when the temperature detected by the thermistor 54 is reduced during the disconnection determination process, the disconnection determination process is terminated, and thus erroneous determination can be prevented.

  In addition, the heating apparatus of this invention is not limited to the structure of the said embodiment, A various change is possible.

  For example, in the above-described embodiment, when the temperature detected by the thermistor 54 is reduced during the disconnection determination process, the disconnection determination process itself is terminated (step S5-9), but the process returns to step S5-1 and decreases. It is good also as a structure which restarts a disconnection judgment process by making temperature into comparison reference temperature T0. In this way, the delay time for adjusting the start time of the disconnection determination process in steps S3 and S4 is not necessary.

  In the above embodiment, the disconnection determination step (step S5) is executed when the preset delay time has elapsed (step S4). However, the thermistor 54 performs hot water measurement while the delay time is being measured (step S4). When the temperature is detected and a decrease in the detected temperature (for example, 1 ° C.) is detected, the measurement time may be cleared and the delay time may be measured again (return to step S3). In this way, even when the user adds water several times during the measurement of the delay time, the presence or absence of disconnection can be reliably detected in the disconnection determination step.

  Furthermore, in the said embodiment, when the disconnection of the boiling heaters 35 and 44 was detected, it was set as the structure which alert | reports to a user using the existing display parts 66-69, However, You may provide a dedicated display part.

  And in the said embodiment, although the abnormality judgment of the boiling heaters 35 and 44 was mentioned taking the example of the electric pot, any heating apparatus which attaches a heater to the container 22, such as a humidifier or a rice cooker, can be applied. Yes, similar actions and effects can be obtained.

It is sectional drawing which shows the electric pot which is a heating apparatus which concerns on embodiment of this invention. It is a disassembled perspective view which shows the heater arrange | positioned at the bottom of a container. It is a disassembled perspective view which shows the heater arrange | positioned at the side part of a container. It is a block diagram which shows the structure of the electric pot containing an operation panel part. It is a flowchart which shows the control by a microcomputer. It is a flowchart which shows the disconnection judgment process of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Exterior body 11 ... Body 17 ... Shoulder body 21 ... Cover body 22 ... Container 34 ... Bottom heater unit 35 ... Bottom boiling heater 36 ... Bottom heat retention heater 43 ... Body heater unit 44 ... Body boiling heater 54 ... Thermistor (temperature detection means) )
71: Microcomputer (control means)
74 ... EEPROM (storage means)

Claims (4)

Two or more heaters connected in parallel and a temperature detection means for detecting the temperature of the object to be heated via the container are disposed in a container for storing the object to be heated, and based on the detected temperature of the temperature detection means. In the heating device that controls the heater and heats the object to be heated,
According to the temperature rise gradient based on the detected value of the temperature detecting means when the heater is energized in a non-disconnected state, and the detected value of the temperature detecting means when the heater is energized in a state where either is disconnected Based on the temperature rise gradient, set a judgment value in advance,
During the heating operation by the heater, a disconnection determination step is performed to determine that any of the heaters is disconnected depending on whether the determination value is exceeded within a predetermined time ,
A heating device characterized in that the disconnection determination step is terminated when the temperature detected by the temperature detecting means decreases during the disconnection determination step . The heating apparatus according to claim 1, wherein the disconnection determination step is started after a predetermined delay time from the execution of the heating operation by the heater. Two or more heaters connected in parallel and a temperature detection means for detecting the temperature of the object to be heated via the container are disposed in a container for storing the object to be heated, and based on the detected temperature of the temperature detection means. In the heating device that controls the heater and heats the object to be heated,
According to the temperature rise gradient based on the detected value of the temperature detecting means when the heater is energized in a non-disconnected state, and the detected value of the temperature detecting means when the heater is energized in a state where either is disconnected Based on the temperature rise gradient, set a judgment value in advance,
During the heating operation by the heater, a disconnection determination step is performed to determine that any of the heaters is disconnected depending on whether the determination value is exceeded within a predetermined time ,
The disconnection determination step is started after a predetermined delay time from the execution of the heating operation by the heater, and the measurement time is cleared when the temperature detecting means detects a temperature drop during the delay time measurement. Heating equipment characterized in that measurement is performed again . Claim is disposed a non-volatile memory means for storing an abnormality determination result of the disconnection determination process, abnormality determination in the case of a predetermined number of times or more, characterized in that the infeasible heating operation by the heater The heating apparatus according to any one of claims 1 to 3 .

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