JPH0585165B2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention provides an electric hot water storage device having a hard circuit for boiling the liquid content and for heating the liquid content at a predetermined temperature below the boiling temperature. It concerns containers.

(Prior Art) Hard circuits directly turn the heater on and off using a temperature-sensitive switch, and have the advantages of being simple, inexpensive, and hard to break down, and are widely used along with soft circuits. In many cases, it has a boiling mode in which the liquid content is boiled, and a heat retention mode in which the content liquid after boiling is heated to a predetermined temperature below the boiling temperature. In the water boiling mode, electricity is supplied to one water heater to heat the liquid at a higher wattage than in the heat retention mode.

(Problems to be Solved by the Invention) In the water boiling mode, the content liquid is heated at a higher W number than in the warming mode, so even water at room temperature can be brought to a boil quickly. However, if the wattage of the water heater is too high, when the temperature of the liquid inside becomes high, the heat from the heater will be difficult to be absorbed by the liquid inside, and the heat will easily escape to the outside, resulting in a large heat loss. In addition, if the heat shielding structure around the outside of the heater is not sufficient, it will be dangerous and cause an increase in weight and cost. Therefore, in reality, the wattage of the water heater is suppressed to such an extent that even if the temperature of the liquid inside rises, the loss of heat to the outside does not increase. Therefore, when boiling water, the temperature of the liquid content does not rise sufficiently and it takes a long time to boil.

The present invention aims to solve the above-mentioned conventional problems by improving the circuit configuration of the water boiling mode.

(Means for Solving the Problems) In order to achieve the above objects, the present invention has the following features:
A second water heater is provided in parallel with the water heater that operates in the water boiling mode of the content liquid heating circuit, and a temperature-sensitive switch is provided in the second water heater to turn off the second water heater at a predetermined temperature before boiling. That is.

In addition, the content liquid heating circuit has a water boiling mode that boils the content liquid, and a heat retention mode that heats the content liquid to maintain it at a predetermined temperature below the boiling temperature, and the predetermined pre-boiling temperature is higher than the heat retention temperature in the heat retention mode. Preferably, the temperature-sensitive switch is provided at a position above the minimum usable liquid level on the wall of the vessel where the heater is provided.

(Function) When the water heater is operated in the water boiling mode, the second water heater parallel to it is also operated at the same time until the temperature sensitive switch senses a predetermined pre-boiling temperature of the content liquid and turns it off. Therefore, until the content reaches a predetermined temperature before boiling, the water heater and the
It is possible to heat the water at a high wattage state with two parallel heaters that do not cause pressure drop, and to quickly raise the water to a predetermined temperature before boiling. When the content liquid reaches a predetermined pre-boiling temperature, the temperature-sensitive switch turns off and cuts off the electricity to the second water boiler heater, so subsequent heating is done by the water heater alone at a low wattage, and the temperature of the content liquid is high. This can prevent the heat of the heater from escaping to the outside.

When the pre-boiling predetermined temperature is higher than the heat retention temperature in the heat retention mode, the content liquid can be raised from the heat retention temperature at high speed even when switching from the heat retention mode to the water boiling mode is performed.

If the temperature-sensitive switch is installed at a position above the minimum usable liquid level on the wall of the vessel where the heater is installed, if the content of the liquid decreases to below the installation position of the temperature-sensitive switch, the heat capacity will be small and the heater will decrease accordingly. However, the parts of the container wall where there is no liquid are not affected by the liquid, and the temperature rises faster than the liquid due to the influence of radiant heat from the heater. Before the predetermined temperature is reached, the temperature-sensitive switch senses the pre-boiling temperature from the vessel wall and turns it off. Therefore, since the content liquid is less able to absorb the heat of the heater due to the weight loss, the high W number heating state can be switched from the high W number heating state to the low W number heating state at an early stage.

(Example) An example of the present invention shown in the drawings will be described. In this embodiment, as shown in FIG. 1, an electric pot is used in a stationary state in which the bottom portion of the container body 1 is rotatably received by a group of protrusions 2a of a resin seat body 2. The container body 1 has a metal exterior body 3, into which a resin shoulder body 4 is fitted from above, and the metal inner container 5 is fitted with the shoulder body 4 from above.
The mouth part is latched. A bottom plate 6 made of resin and having a receiving surface 6a for the projection group 2a is applied to the lower end of the exterior body 3, and a metal ring 7 and the inner container 5 are applied to the bottom plate 6 from below. By connecting the metal fittings 8 and the screws 9, the inner container 5 and the ring 7 are attracted to each other, and the constituent members of the container body 1 are fixed to each other. A resin ring 91 is further applied to the ring 7 from below and fixed with screws 10, and the seat body 2 is rotatably sandwiched and held between the ring 91 and the bottom plate 6, and is integrated with the vessel body 1. I am making it possible to handle it.

The rear part of a resin lid 12 is removably connected to a bearing part 11 formed at the rear part of the shoulder body 4 by a hinge pin 13.
It is opened and closed by rotation around 3. Lid 12
is provided with a metal inner lid 13 that closes the mouth of the inner container 5, and is also provided with a bellows pump 14 that pressurizes the liquid inside. 15 is an operation panel of the pump 14, 16 is an air supply path from the pump 14,
17 is a steam relief passage; 18 is a switching valve for selectively using the air supply passage 16 and the steam relief passage 18 when operating the operation plate 15 and when not operating it; and 19 is a valve hole thereof. 21 is a locking member that locks the lid 12 in the closed state.

A pouring pipe line 22 is connected to the bottom of the inner container 5. The spouting pipe 22 is connected to an inverted U-junction 22a located in a passage cover 23 that rises up from the entire inner container 5 and protrudes from the front part of the shoulder body 4, and the discharge port 22b at the tip thereof is connected to the passage cover 23. It faces above the liquid injection guide 24 provided at the bottom of the. As a result, the spouting conduit 22 guides the content liquid to be extruded by the pressure applied by the pump 14, and the liquid is discharged from the discharge port 22b. The discharged liquid is once exposed to the atmosphere to release pressure and mixed air, and then flows into the liquid injection guide 24 and is injected in a quiet flow.

A recess 5a formed on the bottom surface of the inner container 5
A heater 31 is applied inside. Heater 31
is a donut-shaped mica substrate 3 as shown in Figure 2.
A heat retaining heater 31a, a water boiling heater 31b, and a second water boiling heater 31c used as an auxiliary to the water boiling heater 31b are wound around the water heater 31b, and these are sandwiched between mica plates 33, 33 for insulation, and a donut-shaped aluminum case 34 is installed. It is accommodated in A heat radiating plate 35 made of a thick aluminum plate and a heat shield plate 36 made of a steel plate are successively pressed and held on the back side of the case 34 by a leaf spring 37.
The leaf spring 37 is attached with screws 41 to a metal heat shield plate 39 that is attached to the lower surface of the bottom of the inner container 5 with a metal fitting 38 with a small gap. The heat shield plate 39 uses a screw 41 to connect the temperature fuse 4.
2 is also installed.

A thermostat 43 for boiling water and a thermostat 44 for high-speed water boiling are attached to a stepped surface 5b formed at a height H above the minimum usable liquid level L at the back of the inner container 5 by metal fittings 45. (Figure 2). Further, a thermostat 46 for preventing excessive temperature rise is placed at the center of the lower surface of the bottom of the inner container 5 using the center hole 34a of the case 34. The thermostat 46 is attached to a heat shield plate 39 with metal fittings 47, and a cylindrical partition wall 48 is provided between the thermostat 46 and the heater 31 to prevent direct thermal influence from the heater 31.

As shown in FIG. 3, individual lead wires 31 ₁ to 31 ₃ of each heater 31 a to 31 c and a common lead wire 31 ₄ come out from the heater 31 .
a to 31c, thermostats 43, 44, 46,
A temperature fuse 42 and lamps 49, 50 for keeping warm and boiling water (not shown) provided on the front surface of the container body are connected as shown in FIG. 4 to constitute a liquid heating circuit.

In this circuit diagram, 51 is a steam sensor that detects boiling based on the temperature of steam, 52 is a relay, and 52
A is a relay contact, and 53 is a reboiling switch.
The reboiling switch 53 is located together with the lamps 49 and 50 on the lower back side of the resin panel 55 where the liquid level display window 54 is provided on the front side of the vessel body 1, and its operation button 53a faces the through hole 55a of the panel 55. It is configured to be operated by pressing through a cover sheet 56 on the surface of the panel 55.

A downward facing equipment box 6a is provided on the bottom plate 6, and a wiring terminal 61 is provided in a part of this box 6a. Further, a magnetic plug receiver 62 for connection to a power source is provided at the rear of the seat body 2.

The electric circuit shown in FIG. 4 will be explained. The heat retention heater 31a is used alone in the heat retention mode to heat the liquid content to a predetermined temperature range, for example, from around 86°C to around 92°C, and achieves heat retention in balance with the natural heat dissipation of the liquid content. do. For this reason
I am using something around 25W. Water heater 3
1b and the second water heater 31c are connected in parallel with each other and are used simultaneously in the water boiling mode to generate 800W.
The temperature of the liquid inside is raised rapidly by heating the liquid to a certain degree. However, due to heating at 800W, the heat of the heaters 31b and 31c tends to escape to the outside.For example, if the water boiler heater 31b is used alone when the content temperature reaches about 98℃, the heat of the heaters can escape to the outside. It is designed to heat at around 400W, which makes it difficult to use. Therefore, both the water heater 31b and the second water heater 31c are
The high-speed water boiling thermostat 44, which turns on and off the second water heater 31c independently, is designed to turn off at 98° C. or higher.

On the other hand, the water boiling thermostat 43 turns on when the temperature drops below 40°C due to replenishment of the liquid content, etc., and switches the circuit to a water boiling mode in which both the water boiling heater 31b and the second water boiling heater 31c are energized at the same time. . At this time, the heat-retaining heater 31a is also energized, so the actual heater wattage in the water boiling mode is 825W.

When the thermostat 43 is turned on, the relay 52 is energized via the steam sensor 51, so the relay contact 52a is turned on, self-holding the relay 52, and also turning on the water heater 31b and the second water heater 31.
c. By forming a bypass circuit that conducts electricity to both sides, the circuit remains in the water boiling mode even if the water boiling mode is switched to, the temperature of the liquid content recovers to over 40°C, and the water boiling thermostat 43 is turned off.

In the water boiling mode, the temperature of the liquid content rises at a high speed especially by simultaneous energization of the heaters 31b and 31c.
When the internal solution reaches 98° C., the high-speed water boiling thermostat 44 is turned off and the power supply to the second water boiling heater 31c is cut off. This switches to heating at 425W using only the hot water heater 31b and the heat retention heater 31a, so even if the content liquid becomes difficult to absorb heater heat due to temperature rise, the heat of the heater 31 is halved, so the heater The heat of 31 becomes difficult to escape to the outside, and although the amount of heat is small, the temperature of the content liquid can be raised to boiling in a relatively short time with sufficient thermal efficiency.

When the content liquid boils, the steam temperature at that time turns off the steam sensor 51 located in the middle of the steam release passage 17 and cuts off the power to the relay 52, so the relay contact 52a is turned off and the circuit returns to the heat retention mode.

As a result, the content liquid is heated at 25W only by the heat retention heater 31a, and the heat radiation of the content liquid is greater than the heating, and the temperature of the content liquid decreases, but when the temperature range is reached, there is a balance between heating and heat radiation. can be removed, so the content liquid can be kept within the insulating temperature range.

When the reboiling switch 53 is turned on during the heat retention mode, this also energizes both the boiling heater 31b and the second boiling heater 31c and the relay 52, and the circuit is controlled by the water boiling thermostat 43. Switch to boiling water mode as usual.
At this time, the high-speed water boiling thermostat 44 is turned on because the content liquid is in the heat retention temperature range, and the second water boiling heater 3 is turned on until the content liquid reaches a temperature of about 98°C.
1c works to rapidly raise the temperature of the liquid inside.

FIG. 5 shows a time chart of the above circuit operation in relation to changes in the temperature of the liquid inside.

When the water boiling mode is performed when the content liquid has decreased to near the liquid level L, the heat capacity is small due to the small amount of content liquid, making it difficult to absorb the heat of the heater 31. However, since the high-speed water boiling thermostat 44 is located above the liquid level L by the height H and is in contact with the part of the inner container 5 where there is no solution, it is not easily affected by the temperature of the inner liquid and the radiant heat from the heater 31 is not affected by the temperature of the inner liquid. The temperature rises faster than the content liquid because it is more susceptible to the effects of Therefore, the high-speed water boiling thermostat 44 senses the temperature before the content reaches the pre-boiling temperature of 98°C and turns off the water, stopping the use of the second water boiling heater 31c. Since it is difficult to absorb the heat of the heater 31, the heater 31 can be switched from a high W number heating state to a low W number heating state at an early stage. Therefore, it is possible to prevent the content liquid from decreasing in volume and becoming difficult to absorb the heat from the heater 31, thereby preventing the heat from the heater 31 from escaping to the outside due to high-speed water boiling.

In addition, the thermostat 46 for preventing excessive temperature rise is set at 110℃.
When the temperature rises to an abnormal level, it turns off to prevent further temperature rise, and when the temperature returns to normal, it turns on and returns to normal use. Also temperature fuse 4
2 is for safety by melting when the temperature rises to around 140℃ due to dry cooking etc.

The switching method between the heat retention mode and the water boiling mode is not limited to the above embodiment, and may be performed in various patterns.
A second water heater may be connected in parallel to the water heater used in the water boiling mode, and the second water heater may be turned off independently at a predetermined temperature or higher before boiling.

(Effects of the Invention) According to the present invention, when the water heater is operated in the water boiling mode, the second water heater in parallel with it is also operated at the same time until the temperature sensitive switch senses a predetermined pre-boiling temperature of the content liquid and turns it off. Therefore, until the content reaches the pre-boiling predetermined temperature, the water boiler heater and the second water boiler heater are heated at a high wattage state that does not cause pressure drop in parallel with each other, and then the content is heated at high speed until the pre-boiling predetermined temperature is reached. can be raised,
When the content liquid reaches a predetermined pre-boiling temperature, the temperature-sensitive switch turns off and cuts off the electricity to the second water boiler heater, so subsequent heating is done by the water heater alone at a low wattage, and the temperature of the content liquid is high. This can prevent the heat of the heater from escaping to the outside. Therefore, the time required for boiling can be shortened without causing heat loss and safety problems due to escape of heater heat to the outside.

If the pre-boiling predetermined temperature is higher than the keep-warm temperature in the keep-warm mode, even when the keep-warm mode is switched to the boiling water mode, the content liquid can be raised quickly from the keep-warm temperature, and as described above. You get the same benefits.

If the temperature-sensitive switch is installed at a position above the minimum usable liquid level on the wall of the vessel where the heater is installed, if the content of the liquid decreases to below the installation position of the temperature-sensitive switch, the heat capacity will be small and the heater will decrease accordingly. However, the parts of the container wall where there is no liquid are not affected by the liquid, and the temperature rises faster than the liquid due to the influence of radiant heat from the heater. The temperature-sensitive switch detects the pre-boiling temperature from the container wall and turns it off before the pre-boiling temperature reaches the pre-boil temperature, so it is difficult to absorb the heat from the heater due to the volume of the liquid in the liquid, so high W-number heating is possible at an early stage. It is possible to switch from the low W number heating state to the low W number heating state, which prevents a large amount of heater heat from escaping to the outside due to water boiling at a high W number, as the content liquid decreases and becomes difficult to absorb the heater heat. be able to.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view showing an embodiment of the present invention, Fig. 2 is a rear view of the thermostat mounting part on the back of the inner container, Fig. 3 is a bottom view of the heater, and Fig. 4 is a diagram of the content heating circuit. , FIG. 5 is a diagram showing the relationship between the temperature rise of the content liquid and the time chart of circuit operation. 1... Container body, 5... Inner container, 31... Heater,
31a... Heat retention heater, 31b... Water boiling heater, 31c... Second water boiling heater, 43... Water boiling thermostat, 44... High speed water boiling thermostat, 52... Relay, 52a... Relay contact, 53... ...Reboiling switch, L...minimum usable liquid level.

Claims (1)

[Scope of Claims] 1. A second water heater is provided in parallel with the water heater that operates in the water boiling mode of the content liquid heating circuit, and the second water heater is provided with a temperature-sensitive device that turns off the second water heater at a predetermined temperature before boiling. An electric hot water storage container featuring a working switch. 2 The content liquid heating circuit has a water boiling mode for boiling the content liquid, and a heat retention mode for heating the content liquid to maintain it at a predetermined temperature below the boiling temperature, and the predetermined pre-boiling temperature is higher than the heat retention temperature in the heat retention mode. The electric hot water storage container according to claim 1. 3. The electric hot water storage container according to claim 1 or 2, wherein the temperature-sensitive switch is provided at a position above the lowest usable liquid level on the wall of the container where the heater is provided.