JP4013919B2 - Electric pot - Google Patents

Description

  The present invention relates to an electric pot that is used for use by heating the content liquid in an inner container accommodated in a container by heating with a heater.

This type of electric pot is widely used, and many have a centrifugal pump that discharges the content liquid (see, for example, Patent Document 1). As shown in Patent Document 1, the centrifugal pump is arranged in the middle of the content liquid discharge path and below the bottom of the inner container, and sends out the content liquid flowing from the inner container into the pump chamber by centrifugal force and discharges it. Therefore, a small and simple impeller can be used. As a result, the content liquid can be automatically discharged and used by operating the centrifugal pump.
JP 2003-235731 A

  However, since an electric pot is a device that incorporates a heater and performs a heating operation, its function is sometimes impaired by the thermal influence from the heater. For example, if the content liquid cannot be discharged as expected, it may take time or be distrusted, and if the remaining amount of content liquid is below a certain level below the warning level for water supply, While safety is detected by detecting abnormal temperature rises below the detection level, there may be functional failures including the control system of the electric pot and mechanical and physical damage to the hardware such as the fluorine coating layer.

  With regard to these, the present inventors conducted various experiments and repeated research.As a result, defective discharge mainly occurs when the content liquid is discharged immediately after boiling, and also occurs when the content liquid is in a high temperature range. It was proved that the pumping of the contents liquid by the impeller was hindered due to the cavity phenomenon generated in the pump chamber and bubbles caused by cavitation. In addition to the high temperature of the content liquid, this is related to the thermal effect on the pump chamber of the centrifugal pump from the heater that was heated until the content liquid was boiled. It seems to promote the boiling of the liquid content.

  On the other hand, control system malfunctions and hardware-related mechanical and physical damages are handled by conventional heater detection and abnormal temperature rise countermeasures by limiting energization or turning off the heater. However, it did not go down easily, and the temperature overshooted unexpectedly, and it turned out to be damaged.

  In the device described in Patent Document 1, forced cooling by a fan is performed to lower the content liquid once boiled to the heat retention temperature. However, the above problems cannot be solved. Moreover, what has solved the above problems has not yet been provided.

  An object of the present invention is to provide an electric pot capable of avoiding malfunction due to heat.

In order to achieve the above object, the electric pot of the present invention discharges the content liquid in an electric pot that is heated and heated by a heater to heat the content liquid in the inner container accommodated in the container and used for use. One feature is that it is equipped with a centrifugal pump and a cooling fan, and the cooling fan is driven to cool the pump chamber of the centrifugal pump when it is predicted that the centrifugal pump will be driven by a person approaching the electric kettle or hot water supply key. Yes.

In such a configuration, the one specific example of a case where the cooling cooling fan power sale have Driving fan is driven by preceding the centrifugal pump from when a prediction of the centrifugal pump drive, pump chamber of the centrifugal pump and its Since the liquid inside is cooled, the temperature is surely lowered when the centrifugal pump is subsequently driven in connection with the prediction, and the discharge function can be further stabilized by further suppressing the occurrence of cavitation.

The electric pot of the present invention also includes a centrifugal pump that discharges the content liquid, a cooling fan, and an electric pot that heats the content liquid in the inner container accommodated in the container body by using a heater to boil and keep warm. And a preliminary operation means for performing preliminary operation prior to the operation of the centrifugal pump. The operation of the preliminary operation means predicts the centrifugal pump drive and drives the cooling fan to cool the pump chamber of the centrifugal pump. Another feature is to do.

  In such a configuration, the centrifugal pump drive can be predicted with high accuracy by the preliminary operation of the centrifugal pump drive, and the cooling fan is driven after this prediction, and the pump chamber of the centrifugal pump and the content liquid therein are cooled. When the centrifugal pump is subsequently driven in connection with the preliminary operation, the temperature is surely lowered, and the discharge function is further stabilized by further suppressing the occurrence of cavitation, and the probability of driving the predicted centrifugal pump is high. The amount of advance cooling by the cooling fan is not wasted.

  Further objects and features of the present invention will become apparent from the following detailed description. Each feature of the present invention can be employed alone or in combination in various combinations as much as possible.

  According to one characteristic of the electric pot of the present invention, cavitation is suppressed by cooling when the centrifugal pump is driven, the discharge function is stabilized, and the discharge can be performed smoothly with high reliability.

  According to another feature of the electric pot of the present invention, cavitation during driving of the centrifugal pump can be further suppressed by cooling from when the driving of the centrifugal pump is predicted, and the discharge function is further stabilized.

  According to another feature of the electric pot of the present invention, cooling from the time when the centrifugal pump drive is predicted with high accuracy by the preliminary operation further suppresses the occurrence of cavitation when driving the centrifugal pump, and further improves the discharge function. Precise cooling by the cooling fan is less likely to be wasted because the probability of driving the centrifugal pump that is stable and predicted is high.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to FIGS. 1 to 12 for understanding of the present invention. The following description is a specific example of the present invention, and does not limit the scope of the claims.

  This embodiment is an example of an electric pot for home use. As shown in FIG. 1 (a), an overall case is made of a stainless steel single container without a special heat insulating structure. 5 has a container 1 housed as an inner container 3, and uses the heater 11 as a heating source to heat the content liquid to boil and keep warm for use. Stainless steel has sufficient bending rigidity and strength, and has a rust-proofing effect, and since it easily exhibits antibacterial properties by containing Cu or the like, it is suitable for an inner container in an electric pot for eating and drinking. The liquid content is discharged to the outside by a centrifugal pump 12 through a pipe-type discharge passage 13 to supply hot water for use. However, the present invention is not limited to this, and a heating coil for heating by electromagnetic induction can be adopted as a heating source.

  In particular, the electric pot according to the present embodiment includes the fan 14 in the container 1, and cooling of the content liquid through the inner container 3, cooling around the heater 11, and cooling of the centrifugal pump 12 are sometimes performed. We are able to respond accordingly. Cooling of the content liquid through the inner container 3 is effective for quickly lowering the content liquid once boiled for sterilization, removal of chalk, etc. to a predetermined heat retaining temperature, and cooling around the heater 11 is mainly performed. It is effective for ensuring the thermal safety of the control system and the hardware surface when detecting empty cooking or detecting abnormal temperature rise, and cooling the centrifugal pump 12 is effective for suppressing the occurrence of cavitation described above.

  Since the inner container 3 is made of stainless steel and has low thermal conductivity among metals, even the single container having no special heat insulation structure cooperates with the outer case 5 made of synthetic resin to The single container without a special heat insulation structure while ensuring a certain degree of heat retention efficiency is efficient for cooling the content liquid after boiling it using the fan 14, and the content liquid after boiling It is suitable for early use by lowering the temperature to a set or selected heat retention temperature in a short time. However, it is not limited to this.

  The specific structure of the electric pot of the present embodiment will be described. The inner container 3 and the outer case 5 are connected to each other between upper end portions by a synthetic resin shoulder member 15 to constitute the container 1. For this connection, for example, the outer flange at the upper end of the inner container 3 is received from below by a shoulder member 15 fitted to the upper end of the outer case 5 by stamping from above, and the bottom of the inner container 3 and the outer case 5 in this state are received. Can be integrated in a separable manner by connecting them to each other with a metal fitting (not shown) and pulling them together. However, the shoulder member 15 can be forcibly fitted to the outer case 5 and the inner container 3 can be screwed to the shoulder member 15. Moreover, the bottom part of the exterior case 5 can also be made into another member.

  The shoulder member 15 is connected to the inner container 3 and the outer case 5 to form an opening 1a of the container 1 that communicates with the opening 3a of the inner container 3, and a lid 17 is attached to and detached from the rear portion of the shoulder member 15 by a hinge pin 16. The openings 1a and 3a are simultaneously opened and closed by being supported so as to be rotatable. In particular, the metal inner lid 18 provided inside the lid 17 faces the opening 3a, and the seal packing 119 sandwiched between the outer peripheral portions of the lid 17 and the inner lid 18 is closely attached to the entire circumference of the opening 3a. To close. In this state, the steam passage 19 that leads from the steam inlet 19a provided on the inner lid 18 to the steam outlet 19b provided on the upper surface of the lid 17 does not allow the liquid contents that may flow into the lid 17 to flow straight. It is formed with a form and a route that delays reaching the steam outlet 19b by accumulating or detouring in the middle. A falling water stop valve 19c is provided on the steam inlet 19a side of the steam passage 19 to prevent the liquid content from flowing into the steam passage 19 when the container 1 falls.

  Further, when the lid 17 is closed at the front portion of the lid 17, the spring 23 is biased to the locking portion 21 by a hole or the like formed on the side of the container body 1, specifically, a part of the shoulder member 15. Are provided with a lock member 22 that engages and locks the lid 17 in a closed state, and a lock release member 25 that releases the lock by the lock member 22. The unlocking member 25 is pivotally supported by the shaft 24, and when the front end 25a is moved downward by the thumb of the hand, the lock releasing member 25 is rotated counterclockwise around the shaft 24 to retract the locking member 22 against the spring 23, The unlocked lid 17 can be lifted open by releasing the lock of the lid 17 in the closed state and lifting the rear end 25b moved upward at that time with an index finger or the like of the hand.

  Further, the hinge pin 16 is fixed to the lid 17 side, and the stopper 27 is inserted into the U-shaped pin receiver 26 formed on the shoulder member 15 with the front side of the container body 1 open while pushing down against the spring 28. Then, since the open part of the pin receiver 26 is closed by the upward movement return of the stopper 27 by the spring 28 after the insertion, the lid 17 is pivotally supported so that it can be opened and closed. The stopper 27 has an operation piece 27a that protrudes to the rear of the container body 1. When the stopper 27 is moved downward against the spring 28 by the operation piece 27a, the pin receiver 26 is opened. The lid 17 can be removed from the container body 1 with the drawer from the receptacle 26. As a result, the lid 17 can be washed.

  The centrifugal pump 12 is provided at a midway position where the liquid content in the discharge passage 13 flows, and at a midway position below the bottom of the inner container 3, and the content that flows into the centrifugal pump 12 by being driven to rotate. The liquid is sent out toward the discharge port 13a facing the outside of the container 1 of the discharge path 13 to be discharged and used. In the middle of the discharge path 13, a water stop valve 31 at the time of overturning and a water stop valve 32 at the time of forward tilt are provided, and in this example, it further rotates according to the difference in the flow rate of the content liquid sent through the discharge path 13 and detects it. A flow sensor 33 is provided.

  The heater 11 is located in a recess 3b formed by forming an upward convex portion on the bottom surface of the bottom of the inner container 3, and is provided with a spring member 35 provided between the heat shield 34 attached with a metal fitting below the bottom of the inner container 3. Is pressed against the lower surface of the bottom of the inner container 3. The discharge path 13 is connected to the upwardly projecting top surface portion formed by the recess 3b, and the remaining amount is secured so as not to discharge the content liquid below the height of the top surface to prevent emptying. In addition, a temperature sensor 36 is applied to a central recess 3b1 formed at the center of the top surface so as to protrude upward, so that the content liquid temperature is detected. As a result, when the content liquid is lowered to the top surface, the central recess 3b1 of the inner container 3 is exposed from the content liquid prior to other ranges and rapidly rises in temperature. It is possible to determine that the amount has been reduced to a level where it cannot be discharged. This is so-called empty cooking detection. Even in this case, when there is no water supply and the remaining amount decreases, an abnormal temperature rise state is detected, and then the temperature fuse (not shown) is blown and the heater 11 is turned off.

  From the portion of the discharge passage 13 where the water stop valve 31 at the time of overturning and the water stop valve 32 at the time of forward tilting are provided to the discharge port 13a, one discharge port side block 13b is formed. 15 is positioned in a protruding portion 37 that protrudes in a bowl shape toward the front portion of the container body 1, and the discharge port 13 a faces downward at the tip portion position of the protruding portion 37 away from the body portion of the container body 1. An operation panel 38 is provided on the upper surface of the protrusion 37. As shown in FIG. 1B, the operation panel 38 has, for example, a heat retention selection key 41 for selecting a heat retention temperature of 98 ° C., 90 ° C., and 60 ° C. in a rotary manner, and hot water supply for discharging the content liquid by operating the centrifugal pump 12 A key 42, a re-boiling key 48 that boils the liquid being kept warm, a hot water lock operation that prevents hot water supply by operating the hot water supply key 42, and a hot water supply lock key 49 that repeats the operation in a rotary manner, other operation keys Various display units are provided. A control board 40 is provided inside the operation panel 38. The control board 40 includes switches (not shown) that respond to the operation of various keys on the operation panel 38, inputs from these switches, a temperature sensor 36, and a flow sensor 33. In response to the input, the microcomputer 11, which controls the heater 11, the centrifugal pump 12, and the fan 14 via the drivers 43 to 45 shown in FIG. Tools, display lamps, and the like are mounted, and a buzzer 47 that performs external auditory notification is mounted as necessary.

  As shown in FIGS. 1A and 2, the fan 14 is provided below the bottom 50 of the inner container 3 in the container 1, and the air outside the container 1 passes around the inner container 3 through the air inlet 60. After aspiration as indicated by an arrow in a), it is collected under the bottom of the inner container 3 and exhausted from the bottom 51 of the container 1. Such a fan 14 is positioned with the heater 11 below the bottom of the inner container 3 and does not increase the bulkiness around the trunk of the container 1, and therefore, the space between the outer case 5 of the container 1 and the inner container is not increased. The outside air is sucked into the space S as narrow as conventional to facilitate contact with the outer peripheral surface of the inner container 3, and the flow of the sucked outside air 53 to be brought into contact with the fan 14 below the bottom 50 of the inner container 3 is created. Then, the outer surface of the inner container 3 is licked so as to reach under the bottom 50, and the heater 11 and the centrifugal pump 12 are brought into contact with each other. Concentrated suction air 53 is exhausted from the bottom 51 of the body 1 through the fan 14, thereby disturbing the flow of the suction air 53 that licks the outer surface of the inner container 3 and the outer surface of the bottom 3. Therefore, the cooling efficiency for the inner container 3 and the content liquid, the heater 11 and the centrifugal pump is increased. Therefore, it is a simple and inexpensive structure in which only the fan 14 is provided, and the outside air is sucked between the outer case 5 and the inner container 3 that forms the body part of the body 1 and does not increase in particular. They can be cooled by contact with the surface, the heater 11 and the centrifugal pump 12.

  In addition, the air inlet 60 is provided at the lower part of the side surface of the container 1, and it is difficult for water to reach from the opening 1 a of the container 1. Becomes even more difficult. Moreover, since the suction force by the fan 14 extends to the upper part around the inner container 3, the suction outside air 53 from the intake port 60 is easily spread to the extent that a negative pressure can be generated there. The suctioned outside air 53 is made to extend along the outer surface of the inner container 3 to sufficiently contribute to cooling of the content liquid.

  Furthermore, the heater 11 is under the bottom 50 of the inner container 3. A fan 14 is provided under the heater 11, and after sucking air outside the container body 1 from the side surface of the container body 1 around the inner container 3, Collected under the heater 11 and exhausted from the bottom 51 of the vessel 1. Thereby, in addition to the above, since the heater 11 is located below the bottom 50 of the inner container 3 and the cooling fan 14 is below it, the outer surface is licked from the outer peripheral surface of the inner container 3 to the bottom 50. The outside air 53 sucked into the fan 14 is effectively applied to the heater 11 below the inner container 3 immediately before exhausting. That is, the temperature rise of the suction outside air 53 due to the cooling of the heater 11 is not disadvantageous for the cooling of the inner container 3 and the content liquid. Accordingly, the suctioned outside air 53 to the fan 14 that licks the outer surface from the outer peripheral surface of the inner container 3 to the bottom 50 is also efficiently lowered by the heater 11 and the centrifugal pump 12.

  Further, in order to exhaust the sucked outside air 53 from the bottom 51 of the container 1 by the fan 14, a blowing part 56 that blows out the exhaust flow 54 along the stationary surface 55 on which the container 1 is placed from below the bottom 51 of the container 1 is provided. It is provided. Thereby, the exhaust flow 54 from the bottom 51 of the container 1 is smoothly blown out along the stationary surface 55 of the container 1 through the blowing part 56. Therefore, the exhaust from the bottom 51 of the container body 1 can be performed smoothly without any deterioration, and the cooling efficiency does not decrease due to exhaust failure.

  As shown in FIGS. 1 (a), 2 and 4, the blowing portion 56 is formed with an upward convex portion 62 having a downward concave portion 61 on the bottom portion 51 of the container 1 formed by the exterior case 5. Then, the exhaust port 63 is formed in the convex portion 62 and the fan 14 is installed thereon, and the blowout port 64 in a state where the concave portion 61 is opened on both the left and right sides is used as the peripheral wall of the concave portion 61. It is formed as a dent from the lower surface of. As a result, the exhaust flow 54 exhausted from the fan 14 to the lower part of the container 1 is once discharged from the exhaust port 63 into the recess 61 closed to the stationary surface 55 of the container 1 and is guided by the stationary surface 55. Then, the air is smoothly discharged from the air outlet 64 to the left and right along the stationary surface 55 to the outside of the air outlet. In the experiments of the present inventors, the temperature is increased to about 60 ° C. as compared with the case where the fan is provided without exhausting such a recess 61. The cooling time is reduced by several tens of minutes. Moreover, the bottom 51 of the container 1 at the outlet 64 in the left-right direction avoiding the front part with the protrusion 37 as shown in FIG. 3 and the rear part with the power connection port 65 as shown in FIG. Therefore, the exhaust air flow 54 does not reach the user or the power connection port 65.

  In addition, the blow-out port 64 has a concave shape that rises from the stationary surface 55 in the bottom 51 of the container 1, so that a hand is put between the bottom 51 of the stationary body 1 on the stationary surface 55 and the stationary surface 55. Create a gap. Therefore, the container 1 can be lifted from the stationary surface 55 by putting a hand in the gap, or can be used as a handle for carrying it as it is.

  As shown in FIG. 2, the fan 14 is an axial fan having twisted blades 14a around the vertical axis and has a flat shape, as shown in FIG. 1 (a) and FIG. In addition, the drive motor 14b and the bottom 50 of the inner container 3 can be installed vertically lower and are accommodated in a rectangular case 72 to which the drive motor 14b is attached. Installation in the container 1 is performed by attaching the cover 62a integrally formed in the ceiling opening 73 of the convex part 62 provided on the bottom 51 of the exterior case 5 and the opening 73 of the convex part 62 from below. The bottom lid 74 is sandwiched between the bottom lids 74 so that they can be held, and an exhaust port 63 is formed in the bottom lid 74. As shown in FIG. 1A, the bottom lid 74 is formed by fitting a plurality of engaging claws 74a formed on the outer peripheral portion into an engaging hole 62b formed on the peripheral wall of the convex portion 62 from one direction. The screw 75 is screwed to the ceiling portion of the convex portion 62, and the engagement claw 74a is attached by being prevented from coming off from the engagement hole 62b. The bottom cover 74 can be removed from the engagement hole 62b. As a result, the fan 14 is attached at the same time without any other structure or work as the fan 14 is attached to the bottom lid 74 with one screw 75.

  Further, an aluminum layer 71 is provided on the outer surface of the inner container 3, particularly on the outer surface of the lower half portion where contact with the suctioned external air 53 is achieved, as shown in FIGS. The aluminum layer 71 may be an aluminum sheet, tape, foil, or a plated layer. As a result, according to experiments by the present inventors, the cooling time to about 60 ° C. was shortened by about 10 minutes or more compared with the case where the aluminum layer 71 was not provided. However, since the ambient temperature around the inner container 3 is kept relatively high under the influence of the content liquid temperature and the heat from the heater 11 in the absence of the suction outside air 53, the heat retention efficiency is not particularly lowered.

  Hereinafter, some examples of specific cooling control by the microcomputer 46 in the present embodiment will be described with reference to flowcharts as appropriate. First, in the example shown in FIG. 6, the centrifugal pump 12 is driven by operating the hot water supply key 42, but the cooling fan 14 is also driven. Thereby, the centrifugal pump 12 discharges the content liquid while the pump chamber 12a and the content liquid in the pump chamber 12a are cooled by being exposed to the suction outside air 53 of the cooling fan 14, so that the cavitation accompanying the rotation of the impeller 12b is performed. Occurrence is suppressed and the discharge function can be stabilized. In addition, since the suction outside air 53 by the cooling fan 14 also cools the content liquid and the heater 11, the occurrence of cavitation is further increased. However, it goes without saying that the cooling fan 14 may be cooled by sending air only to the centrifugal pump 12. When the hot water supply key 42 is turned off, the centrifugal pump 12 and the cooling fan 14 are turned off, and the discharge of the content liquid and the cooling of the centrifugal pump 12 are stopped. Therefore, it is highly reliable and can be discharged smoothly.

  Although not shown, if the cooling fan 14 is driven when the centrifugal pump 12 is predicted to be driven and the pump chamber 12a of the centrifugal pump 12 is cooled, the centrifugal pump 12 is predicted to be driven. Since the cooling fan 14 is driven from time to time to cool the pump chamber 12a of the centrifugal pump 12 and the liquid content therein, the temperature is surely lowered when the centrifugal pump 12 is subsequently driven in connection with the prediction. Further, the discharge function can be further stabilized by further suppressing the occurrence of cavitation. Here, the driving of the centrifugal pump 12 can be predicted by approaching a person to the electric pot, in particular, the hot water supply key 42, and a premise operation and spare operation for operating the hot water key 42 such as an unlocking operation by the hot water supply lock key 49. Presence of operation can be predicted with high accuracy. Such a preliminary operation includes a case where a discharge amount and a discharge flow rate are set before discharging. Thus, the advance cooling by the cooling fan 14 is less likely to be wasted due to the higher probability of driving the centrifugal pump 12 predicted in this way. The hot water supply lock is automatically performed when a predetermined time elapses after the hot water supply key 42 is operated, without the lock operation by the hot water supply lock key 49. When the hot water supply lock key 49 is operated in the hot water supply lock state, the hot water supply lock is released, and when the hot water supply lock key 49 is operated in the hot water supply lock release state, the hot water supply lock state is established.

  In the example shown in FIG. 7, when the hot water supply lock is released as a preliminary operation during the heat retention control, the cooling fan 14 is driven to cool the centrifugal pump 12 and the like, and is stopped after a predetermined time x has elapsed. . As a result, the centrifugal pump 12 and the like can be cooled before the hot water supply by the hot water supply key 42 is started, and the cooling fan 14 can be used when the predetermined time x elapses regardless of whether the hot water supply operation is performed within the predetermined time x. Since it is stopped, it is possible to avoid the content liquid from being excessively cooled.

  In the example shown in FIG. 8, when there is a hot water supply unlocking as a preliminary operation during the heat retention control, it is determined whether the liquid temperature is 98 ° C. or higher, and the cooling fan 14 is driven only when it is 98 ° C. or higher. 12 etc. are cooled. The driving of the cooling fan 14 is turned off depending on whether the content liquid falls below 98 ° C. or a predetermined time, for example, 20 seconds elapses. If there is a hot water supply operation by the hot water supply key 42 during the elapse of 20 seconds, the centrifugal pump 12 is continuously driven until the operation of the hot water supply key 42 is released, and the centrifugal pump 12 is stopped by releasing the operation of the hot water supply key 42. I have to. In this way, by driving the cooling fan 14 for a predetermined time only when the content liquid is in a high temperature state even when the hot water supply lock is released, it is possible to prevent unnecessary driving of the cooling fan 14 and excessive cooling due thereto.

  In the example shown in FIG. 9, when boiling is detected, a 60-second cavitation timer is started and then the cooling fan 14 is started to cool the centrifugal pump 12 and the like. 14 is turned off to shift to heat insulation control. Further, the cooling fan 14 can be turned off at the time when the content liquid has fallen from the boiling temperature by a certain value or at the time when the temperature has fallen by a certain value. Thereby, it is possible to suppress cavitation in the centrifugal pump 12 from the time of hot water supply immediately after boiling, and it is preferable to drive the cooling fan 14 at high speed, and even if the cooling fan 14 is rotated at high speed until it stops. Alternatively, the rotational speed may be decreased stepwise or gradually along the way. The content liquid temperature for stopping the cooling fan 14 is about 98 ° C., for example.

  According to an experiment conducted by the present inventors, when the cooling fan 14 is not driven to discharge the content liquid for 30 seconds when the remaining time is displayed as “1 minute” in boiling water at 1 L, When driven, there is a difference as shown in Table 1 below. When the cooling fan 14 is not driven to discharge the content liquid for 30 seconds at the time of “boiling notification”, “3 minutes left” When the cooling fan 14 is driven from the time when the remaining time is displayed, there is a difference as shown in Table 1 below with respect to IV.

(単位：ｍｌ)
以上から、ＩとＩＩとではあまり差はなく、ＩＩＩとＩＶとでは平均１００ｍｌの差があり、沸騰前から冷却ファン１４を駆動するのが好適である。

(Unit: ml)
From the above, there is not much difference between I and II, and there is an average difference of 100 ml between III and IV, and it is preferable to drive the cooling fan 14 before boiling.

  In the example shown in FIG. 10, when the detected temperature of the content liquid reaches 96 ° C. in the boiling operation, the content liquid temperature is a constant value while the cooling fan 14 is driven with an output of 1/3, while proceeding to the boiling detection subroutine. For example, at a temperature of 100 ° C. or more, immediately after detecting boiling, the heater 11 is turned off and the cooling fan 14 is fully driven at an output of 3/3 for a predetermined time, for example, 60 seconds. It is trying to shift to control. Thus, if the detected temperature of the content liquid is above a certain level and boiling is detected, cavitation is likely to occur when the centrifugal pump 12 is driven, but from this point on, the detected temperature falls from the boiling temperature by a predetermined value or correspondingly. Since the cooling fan 14 is driven until the time has elapsed to cool the pump chamber 12a of the centrifugal pump 12 and the liquid content therein, the centrifugal pump 12 is driven not only after that but also immediately after the boiling is detected. Even when the pump 12 is driven, the centrifugal pump 12 and the content liquid are cooled in parallel therewith, so that the discharge function can be stabilized by suppressing the occurrence of cavitation. Moreover, since the cooling fan 14 is driven with 1/3 output from when the content liquid temperature exceeds the predetermined value until the boiling is detected, the boiling is detected after the content liquid temperature becomes equal to or higher than the predetermined value. Since the overshoot of the content liquid temperature during the process is suppressed, the generation of high-temperature steam is suppressed, and the time required for the cooling fan 14 to lower the temperature to a predetermined temperature, for example, about 98 ° C. after boiling, is shortened.

  In the example shown in FIG. 11, when empty cooking is detected in the hot water operation, the cooling fan 14 is driven for a predetermined time x to cool at least the heater 11. As a result, if there is an empty cooking detection in the boiling operation in which the heater 11 has a strong output, the temperature of the heater 11 and its surroundings will rise sharply, and the temperature will not drop easily even if the output of the heater 11 is reduced or stopped. When the chute is experienced, the cooling fan 14 is driven to forcibly cool at least around the heater 11 and the temperature is lowered around the heater 11, so that unexpected damage to the control system and hardware can be avoided. . Such control is effective if it is also performed when an abnormal temperature rise in the next stage is detected.

  By simply turning off the heater 11 at the time of detection of empty cooking, the surface temperature of the fluorine coating around the bottom of the inner container 3 rose to a maximum of about 300 ° C. as shown in FIG. As shown in FIG. 12B, the maximum temperature when the fan 14 was fully driven was suppressed to 268 ° C., and the fluorine coating layer could be protected.

  In the boiling detection, if the amount of liquid determined by the rate of temperature rise of the content liquid is not more than a predetermined amount of the rated capacity of the electric pot, for example, not more than 1/2, the microcomputer 46 has a temperature near boiling or boiling. If the cooling fan 14 starts to be driven immediately after it is detected and stops when the content liquid falls from the boiling detection temperature to a predetermined temperature, for example, 98 ° C., cavitation can easily occur if the content liquid is low. .

  In addition, when the cooling fan 14 is in a driving state, when the preliminary operation such as releasing the hot water supply lock is performed, or when the centrifugal pump 12 is driven by the operation of the hot water supply key 42, the rotational speed of the cooling fan 14 is increased. The cooling effect can be enhanced.

  Further, the cooling of the centrifugal pump 12 by the cooling fan 14 can be performed immediately after boiling of the content liquid or when the heat retention selection is 98 ° C.

  Further, the cooling fan 14 is controlled by the temperature inside the body 1 detected by a temperature sensor provided on a circuit board such as the control board 40 in the body 1 or the temperature of an electronic component having a remarkable temperature rise characteristic. It can be driven to cool the centrifugal pump 12, the heater 11, the electronic component, and the like.

  Further, the drive control of the cooling fan 14 is driven by the temperature inside the body 1 detected by a temperature sensor provided on a circuit board such as the control board 40 in the body 1 or the temperature of an electronic component having a remarkable temperature rise characteristic. It is also possible to variously change the number of rotations. Such a change in the number of revolutions can be performed by controlling voltage or current, or by driving or non-driving duty ratio control.

  The present invention can be applied to an electric pot and can avoid malfunction due to heat.

It is the whole sectional view and block diagram of a control circuit which show one example of an electric pot concerning an embodiment of the invention. It is the perspective view seen in the cross section which shows the exterior case and its bottom part structure of the electric pot of FIG. It is an external appearance perspective view of the exterior case of the electric pot of FIG. It is the external appearance perspective view which looked at the bottom part of the exterior case of the electric pot of FIG. 1 upward. It is the perspective view seen from the cross section which shows the inner container and its bottom part of the electric pot of FIG. It is a flowchart which shows the example of pump cooling control by the cooling fan at the time of hot water supply with the electric pot of FIG. It is a partial flowchart which shows the example of pump cooling control by the preliminary | backup operation with respect to the hot water supply with the electric pot of FIG. It is a flowchart which shows the modification with respect to control of FIG. It is a flowchart which shows the example of pump cooling control by the boiling detection in the electric pot of FIG. It is the flowchart which showed the example of pump cooling control by the content liquid temperature more than predetermined value in the electric pot of FIG. 1, and boiling detection. It is a flowchart which shows the example of heater cooling control by the empty cooking detection in the electric pot of FIG. 12 is a time chart showing a comparison of the temperature rise on the surface of the fluorine coating layer at the bottom of the inner container when the cooling fan of FIG. 11 is driven and when it is not.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Container 3 Inner container 5 Exterior case 11 Heater 14 Fan 36 Temperature sensor 38 Operation panel 40 Control board 46 Microcomputer 60 Inlet 63 Outlet 64 Outlet

Claims (2)

In an electric kettle that heats the content liquid in the inner container accommodated in the container with a heater, heats it, and keeps it warm for use.
It is equipped with a centrifugal pump that discharges the content liquid and a cooling fan, and when the centrifugal pump is predicted to be driven by a person approaching an electric pot or hot water key, the cooling fan is driven to cool the pump chamber of the centrifugal pump An electric kettle characterized by. In an electric kettle that heats the content liquid in the inner container accommodated in the container with a heater, heats it, and keeps it warm for use.
A centrifugal pump that discharges the content liquid, a cooling fan, and preliminary operation means that performs preliminary operation prior to that in connection with the drive of the centrifugal pump, and predicting the centrifugal pump drive by the operation of this preliminary operation means, An electric pot characterized by driving a cooling fan to cool a pump chamber of a centrifugal pump.

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