CN2251324Y - Ceramic electric cooker - Google Patents

Abstract

The utility model relates to a ceramic electric cooker which is characterized in that an electric cooker body is composed of a metallic inner wall which is in contact with a heating body, an intermediate insulating layer and a casing. A temperature control device is composed of a function setting circuit and a PID temperature control circuit. Therefore, the utility model overcomes the main defects that the cooker body of the existing electric cooker is easy to be broken, a ceramic inner cooker has a high fabricating requirement, etc.

Description

Pottery is by pot for cooking rice

Utility model is about the improvement to ceramic electric cooker, especially to the improvement of electric cooker heating, temperature regulating device.

Ceramic electric cooker, the pot body material because of its uniqueness more and more is subjected to people and welcomes.Yet because the pot heat conductivility is low in the pottery, thermal characteristics is poor, and the electric cooker heating and temperature controlling device mostly adopts the design and the structure of pot electric cooker in the virgin metal again, is example to cook, and is heated to moisture content with high-power direct bottom and dryouies.The high-power direct heating in bottom causes in the pottery the local hard intensity of pot to be heated easily, causes temperature of boiler inhomogeneous and break.For overcoming the deficiency of above-mentioned prior art, prevent from that a pot body part sharply is heated to cause non-uniform temperature and a pot body is broken that the someone proposes to adopt low-power, and (general (200 watts) heating, but prolonged the time of cooking like this is unaccommodated.Chinese patent 89213751 discloses and a kind ofly at first pot has been heated to 90-100 ℃ with high-power in pottery, then changes the ceramic electric cooker that miniwatt is heated to predetermined temperature 102-104 ℃ over to.Yet above-mentioned heating, temperature control still have its deficiency, the heating of single bottom can not overcome pot heat transmissibility difference in the pottery and the deficiency brought, secondly, directly bottom heating, pot bottom flatness in the pottery is had relatively high expectations, require the bottom of a pan and heating board to form and fit tightly, otherwise it is bad that the pot body heat transferring still takes place easily, cause pot interior food half-cooked, reach the temperature non that is directed at because of local heating and cause a pot body to break, bring difficulty for undoubtedly a pot system, yield rate is the end of than.Chinese patent 88214477 proposes at the ceramic electric cooker waist additional electrical gas ket to be installed, and reaches the pot body is evenly heated, but increased manufacture difficulty.Above-mentioned besides ceramic electric cooker function singleness, be not suitable for burning, boiling soups food.Ceramic electric cooker also causes a pot body to break owing to lack the protected by temperature limitation device easily in addition, and lacks timing working control, and this also is its deficiency.Therefore still having is worth improved place.

The purpose of utility model is to overcome the deficiency of above-mentioned prior art, and pot heat characteristic in a kind of suitable pottery is provided, and is simple for production, and bottom of pot body is required relatively the end of than, can cook and can hot plate the multifunctional ceramic electric cooker of soup group food.

Another purpose of utility model be to provide a kind of have the protected by temperature limitation device and or the multifunctional ceramic electric cooker of timing working.

The purpose of utility model realizes, it is main that to improve one be that the electric cooker internal wall pot body is made metallic object with the bottom heater thermo-contact, thereby all sidewalls of pot in can the heat radiation heating ceramic, dwindle because of the heating of single bottom, pot causes slowly owing to heat transfer in the pottery pot bottom and all sidewall temperature difference, the 2nd, adopt the PID temperature-control circuit, realize two sections heating, during promptly in the pottery pot of heating, after reaching predetermined initial temperature controlling point, adopt the gap to be heated to the setting terminal temperature then; The 3rd, set the difference in functionality shelves according to burning food; Promptly preset different terminal temperatures, and heat according to the difference in functionality adjusting play.According to above-mentioned design, the utility model ceramic electric cooker, comprise pot, bottom heater, the temperature element that contacts with the bottom of a pan and temperature control equipment in electric cooker body, the pottery, it is characterized in that said electric cooker body by forming with the metal inner surface of heater thermo-contact, middle heat-insulation layer and shell, said temperature control equipment is made up of function setting circuit and PID temperature-control circuit.

The said temperature element of utility model can be all temps sensor, and as PTC, thermistor, thermopair, diode, electric contact thermometer etc., its function becomes electric signal output with the temperature transition that records, and is made for temperature control signals.A kind of less expensive for adopting diode to make temperature element.

Said function setting circuit main is indication difference in functionality shelves, the 2nd, give temperature-control circuit different control variable, can be the stepping circuit used always for example by step switch, pilot lamp, and peripheral circuit form, also can by button trigger switch, integrated circuit counter, pilot lamp, and peripheral circuit form, be excellent with the integrated circuit counter circuit especially wherein, the significance bit of counter at least should be greater than N+2 (N be function shelves numbers).

Said PID temperature-control circuit is heated to predetermined initial temperature with electric cooker, and controlling and driving clearance control circuit gap is heated to terminal temperature then.A kind of embodiment preferably is for adopting the amplification and the comparator circuit characteristic of operational amplifier, the i.e. temperature survey amplification control circuit of forming by a plurality of operational amplifiers and drive the analog control circuit that the oscillatory circuit, ultimate temperature control circuit, thermal circuit etc. of gap heating are formed by the initial temperature-adjusting circuit that comparator circuit constitutes.

The principle of compositionality of utility model and functional characteristics will cooperate an indefiniteness embodiment to be illustrated.

Fig. 1 is the utility model structural representation.

Fig. 2 is the utility model electrical schematic diagram.

Fig. 3 utility model temperature control block diagram.

Fig. 4 is embodiment temperature control equipment circuit theory diagrams.

Embodiment: the electric cooker body is formed by shell 2, heat-insulation layer 3 with the metal inner lining 4 of heater thermo-contact.Heater (dish) 7 is arranged at pot 1 bottom in the pottery, and there is with it the temperature element (diode) 6 that well contacts interior pot bottom appropriate location, and PID temperature control equipment 5, function setting device 10, pilot lamp 9.Course of work Fig. 2, at first according to burning food setting work shelves, to cook is example, the bottom heat-generating disc begins heating during work, the heat that heat-generating disc produces directly heats the interior pot bottom of pottery of thermo-contact with it on the one hand, simultaneously heat-generating disc passes to heat the pot body metal inner lining of pot in the encirclement pottery of thermo-contact with it, and radiation heating pottery pot body sidewall, makes in the pottery pot bottom and sidewall on every side heat the minimizing temperature difference jointly.Temperature element detection that contacts with the bottom of a pan and drive controlling heating, when heating surpasses setting initial temperature T0, gap heater circuit cut-in operation, slowly heat in the gap, until reaching the setting terminal temperature, disconnects calandria and stop heating, changes the heat insulation work state over to.Heating temperature control principle of work is referring to Fig. 3.

A kind of typical PID temperature-control circuit simulation temperature control circuit as shown in Figure 4, the i.e. temperature survey amplification control circuit of forming by a plurality of operational amplifiers and drive the analog control circuit that the oscillatory circuit, ultimate temperature control circuit, thermal circuit etc. of gap heating are formed by the initial temperature-adjusting circuit that comparator circuit constitutes.Its temperature control principle is that the voltage after thermometric is amplified is sent into each comparer, relatively controls corresponding actions by each comparer impression then.

Referring to Fig. 4, temperature-control circuit mainly adopt two LM324 four-operational amplifiers and MC14017 decade counter (other as eight advance, 16 advance etc. all can) form.MC14017 and peripheral circuit are as function selecting and function indication, button touches membrane switch K2 one termination power positive pole, the other end is connected to MC14017 clock input pin 14 as selecting the signal input by resistance in series R27, press the button switch, 14 pin obtain a high level, counter meter one, Q0 is output as high level, all the other are low level, release button, and 14 pin become low level by resistance R 28 ground connection that are attempted by between 14 pin and the ground; By a pushbutton switch, 14 pin are connected to positive source by R27 and obtain high level again, and output state changes again once, recursion successively, because the counter output pin has only a pin to be high level at every turn, all the other all are low level, can realize that therefore difference in functionality selects.Because this example is only used four kinds of functions (cook soon, cook slowly, Baoshang, pot congee), therefore output pin Q5 is connected to 15 pin clear terminals by a diode D3, when Q4 is high level, again by a pushbutton switch, Q5 becomes high level, and this high level is added to 15 pin clear terminals by D3, makes counter O reset turn back to original state, be that Q0 becomes high level, Q0 is connected to A7.9 by resistance in series R11 and orders about the disconnection heat-generating disc.Four function output pins of MC14017 respectively the diode D by serial connection and resistance R, and divider resistance R29 be connected to A6.10, the square-wave generator control gap of forming according to difference in functionality shelves control A6 is heated to terminal temperature.The effect of diode D is when the MC14017 output pin is low level, plays the reverse bias effect.Pilot lamp L is attempted by between each function output pin and the power ground by resistance in series R31, and playing the merit shelves can indicative function.Each function shelves resistance value is inverse ratio with final design temperature.

The reverse amplification circuit that operational amplifier A 1 is formed constitutes reference voltage source jointly with the reference voltage source voltage stabilizing diode such as the IN44/33A (also can be reference voltage source chip etc.) that are serially connected in ground connection and operational amplifier A 1 positive input 12, utilize the feedback characteristics of operational amplifier to make output terminals A 1.14 obtain a voltage more accurately, make input voltage source for each comparer, can improve the precision of control.Change the adjustable resistance WZ that is connected on A1.13.14 pin two ends that collapses and to adjust output.The A1.13 pin is by resistance in series R37 ground connection.

Differential six circuit of putting that operational amplifier A 2 is formed constitute the thermometric amplifying circuit with the temperature element diode.Link to each other with A2 positive input 3 after resistance R 16, the R17 dividing potential drop, link to each other with A2 reverse input end 2 after temperature element, the biasing resistor R22 dividing potential drop.When temperature raises, the electric current that flows through the temperature element diode increases, thereby the R22 pressure drop increases, input voltage diminishes, because temperature variant input voltage is connected to the backward end of A2, makes that therefore temperature raises, the A2 output voltage also raises, change biasing resistor R22, can change the bias current size, thereby change the input voltage size.

The comparator circuit that operational amplifier A 5 is formed, control break heater type of heating, A5 in-phase end 12 joins with reference voltage after resistance in series R7, R30 dividing potential drop, and inverting input 13 amplifies output by resistance R 2 and thermometric and links to each other.When temperature T＜T0 (initial temperature), U13＜U12, U14 is high level, the heat-generating disc work of control rear end; As temperature T＞T0, U13＞U12, U14 becomes low level, and the square-wave generator work of control rear end changes over to and burns the gap heating slowly.Being serially connected in D18, R5 between A5.12 and A5.14 has eliminated output effectively and has fluctuateed when being overturn.

Comparator circuit that operational amplifier A 6 is formed and the capacitor C 2 that is serially connected between A6 inverting input 9 and ground connection are formed square-wave generator (oscillatory circuit), make output be square wave oscillation, and the control heat-generating disc connects the terminal temperature that the selected function gap is heated to setting.Comparer reverse input end 9 also amplifies output terminals A 2.1 by resistance in series R15, R14, R23 with thermometric and links to each other, and A6.9 also links to each other with reference voltage by D11, and links to each other with the voltage follower output terminal 7 that operational amplifier A 3 is formed by D8.Positive input 10 links to each other with comparer A5 output terminal 14 by forward conduction diode D2, and normal phase input end 10 also links to each other with function selecting output simultaneously, and therefore 10 pin are controlled by function and two level of initial temperature.Voltage follower positive input 5 amplifies output terminal 1 by resistance R 23 and thermometric and links to each other, and reverse input end 6 directly links to each other with output terminal 7, makes to export to follow the variation of input and change.The input end of square-wave generator is controlled by three aspects: a. initial temperature control A5.14, b. function setting shelves, c. measure and amplify output A2.1.The course of work is, cooking bottom temperature＜T0, A5.14 are high level D2 conducting, and making A6.8 is high level, drives to connect heat-generating disc, and R25, D10 instead end partially simultaneously, and the A6.8 high level charges to C2 by R15, and the C2 both end voltage is slowly raise; As cooking bottom temperature continuation rising＞T0, A5.14 sports low level, and D2 instead ends partially, this moment, A6.10 voltage was determined by the function setting shelves, grade output voltage wherein cook soon still greater than A6.9 (all the other third gear voltages then are lower than A6.9), and A6.8 still is a high level, the heat-generating disc heating that works on.Cooking bottom temperature raises, make A6.9 voltage raise when the voltage rising) during A6.10, A6 upset A6.8 becomes low level, control rear end heat-generating disc disconnects, while R25, the D10 conducting, A6.10 voltage step-down (the reduction value is determined by R25), C2 begins discharge by R15, A6.9 voltage descends, and as A6.9 voltage decline＜A6.10, A6 upset A6.8 is high level, connect the rear end heat-generating disc, and by R15 C2 is charged R25 once more, D10 instead ends partially, and A6.10 voltage raises, when C2 charges to A6.9＞A6.10, A6 upset A6.8 is low level and disconnects heat-generating disc, and so continuous repetition the square wave in low high level gap occurs in output terminals A 6.8, thereby drives the work heating of heat-generating disc gap, rear end.Owing to the A6.9 terminal voltage along with temperature raises, and under the effect of A3 voltage follower and bias diode D8 clamper, A6.8 becomes initial voltage that low level (heat-generating disc disconnection) C2 begins to discharge also along with rising like this, and it is elongated flip-flop transition to discharge into A6.The square-wave generator driving connection heat-generating disc time only depends on that the function shelves are different and different, and is irrelevant with the heat-generating disc temperature; The height that depends on the heat-generating disc temperature trip time prolongs with the temperature rising.The reverse input end and the output terminal of operational amplifier A 3 are connected to form voltage follower circuit, make output A3.7 follow input A3.5 and change, and under the clamping action of D8, have guaranteed that the C2 discharge initiation voltage raises and raises along with temperature.The clamping action of D11 has been kept the A6.9 rheobase, prevents that the C2 discharge generation from burning slower and slower, even left alone without help phenomenon.Change C2, R15, R25 value can change square width, and C2 increases, and impulse electricity is slack-off, and square wave is broadened; R15 increases that impulse electricity is slack-off, and square wave broadens, and therefore changes output square wave interval time by changing the big I of R15, C2.R25 and D10 effect also are to be used for changing trip time.Above-mentioned operational amplifier A 6, A3, C2 form gap heating oscillatory circuit jointly.

Operational amplifier A 8 is formed comparator circuit, and reference voltage adds to A8 reverse input end 6 through R38, and temperature voltage signal adds to A8 input end 5 in the same way through R3.After temperature overstep of end point ultimate temperature, the A8 upset, A8.7 is high level, makes the insulation pilot lamp of serial connection bright on the one hand, simultaneously this high level is added to A7 comparer inverting input 9, makes electric cooker change keeping warm mode over to.Be attempted by the fluctuation of D19 when eliminating the A8 upset between A8.5 and 7, and make and change insulation back 7 pin over to and keep high level.

Operational amplifier A 4 is formed comparator circuit, and reverse input end 2 is connected to the thermometric amplifier out by resistance R 2 and experiences temperature signal; Reference voltage adds to in-phase input end 3 by resistance in series R18, R19 and R20 dividing potential drop.Diode D9 is connected to A8.7 and R18 and R19 dividing point, and the effect of D9 is to guarantee to power on the back when neutral gear, and A4.2 voltage is higher than A4.3, guarantees that output A4.1 is a low level, makes A7.8 also be low level, prevents empty the burning.When temperature was higher than the terminal point ultimate temperature, A8.7 was high level, and D9 instead ends partially, made A4 be output as low level, and control disconnects heat-generating disc, and this moment, A4.3 voltage was insulation point control voltage.

The comparator circuit that operational amplifier A 7 is formed, the direct pilot relay duty of output terminal (being the heat-generating disc duty), inverting input 9 is influenced by the Q0 of function setting circuit MC14017 and two signal sources of terminal point ultimate temperature control circuit output, and in-phase input end 10 is influenced by thermal circuit and the output of square-wave generator circuit.During neutral gear, do not have the A8.6＞A8.5 that heats, making A8.7 is low level, and the MC14017 Q0 that powers on is that high level send through R11 and puts A7.9, and making A7.8 is low level, and D5 is anti-to be disconnected by heat-generating disc partially; Work (arbitrary shelves) and the temperature of heating is lower than the terminal point ultimate temperature, and MC14017Q0 is a low level, and A8.7 also is a low level, and A6.8 and A4.1 all keep high level, and institute is so that A7.8 keeps high level, and the D5 forward conduction is connected heat-generating disc.In case after surpassing initial temperature controlling point, because A6.8 output level height checker, thereby upset A7, alternately connect, disconnect heat-generating disc, enter slow heated condition; Enter keeping warm mode, A8.7 is upgraded to high level, and the insulation lamp is bright, high level produces a reset signal and makes the MC14017 zero clearing that links to each other with A8.7, and Q0 is upgraded to high level, and this moment is because temperature is still higher, A4.1 is a low level, makes that A7.8 is a low level, and heat-generating disc is not worked.Along with temperature reduces, A4.2 descends, the A4 upset, A4.1 exports high level, makes A7.10 voltage) A7.9, A7 upset output is high level and connects heat-generating disc; Temperature raises, and makes A4 upset output be low level, and circulation realizes insulation repeatedly.

Enter keeping warm mode (press the button and touch membrane switch K1) separately, reach the terminal point ultimate temperature when being equivalent to heating work, give A8.5 one high level, make output A8.7 be high level, unclamp K1A8.7 still for high level because the self-locking of D19 makes, promptly enter above-mentioned keeping warm mode.

The utility model electric cooker also is provided with overtemperature protection device on heat-generating disc, a kind of more simple and effective protective device is a temperature fuse.

The utility model electric cooker also can be before K2 two ends (Fig. 4) or heat-generating disc power supply the time-controlling arrangement of the amount of establishing timing power supply, make in the time really need cooking and start working automatically, cook rice over a slow fire to reach using electricity wisely and to prevent.

The utility model temperature-control circuit can also be to be realized by pid number circuit and program.Gap heating oscillatory circuit also can adopt the RC oscillatory circuit.The thermometric amplifying circuit can adopt common amplifying circuit.Substituting or the like of temperature element all truely used novel protected scope.

Utility model is owing to adopt the good metal internal wall pot body of heat conduction to heat by bottom heat-generating disc heat auxiliary radiation, thereby overcome single bottom directly burning type effectively and caused that pot bottom and sidewall temperature greatly in the pottery, the defective of easy explosion, also fallen at the end simultaneously requirement, improved yield rate pot bottom flatness in the pottery.Be equipped with two sections different heating modes again, make heating be more suitable for pottery pot characteristic.Difference in functionality shelves (essence is different terminal temperatures) not only can be cooked electric cooker, and can be burnt the group food that stews, and low terminal point ultimate temperature and sidewall auxiliary heating make the stewed band of burning soup food can not produce soup and overflow a pot body.The difference in functionality shelves adopt different heating, help energy savings.That the function stepping circuit that PID simulation temperature-adjusting circuit that a plurality of operational amplifiers are formed and counter are formed has is simple in structure, cost is low, reliable operation.Diode is made temperature element, and is economical and practical, good reliability.Protected by temperature limitation device and work timing device make the electric cooker more perfect functions.

Claims (8)

1, a kind of ceramic electric cooker, comprise pot, bottom heater, the temperature element that contacts with the bottom of a pan and temperature control equipment in electric cooker body, the pottery, it is characterized in that said electric cooker body by forming with the metal inner surface of heater thermo-contact, middle heat-insulation layer and shell, said temperature control equipment is made up of function setting circuit and PID temperature-control circuit.

2, according to the described ceramic electric cooker of claim 1, it is characterized in that temperature survey amplification control circuit that said PID temperature-control circuit is made up of a plurality of operational amplifiers and drive the analog control circuit that the oscillatory circuit, ultimate temperature control circuit, thermal circuit etc. of gap heating are formed by the initial temperature-adjusting circuit that comparator circuit constitutes.

3, according to the described ceramic electric cooker of claim 1, it is characterized in that said function setting circuit is made up of counter and button trigger switch, the significance bit of said counter is greater than N+2.

4,, it is characterized in that said button trigger switch is the membrane type touch-switch according to the described ceramic electric cooker of claim 3.

5,, it is characterized in that said temperature element is a crystal diode according to the described ceramic electric cooker of claim 1.

6,, it is characterized in that said each function shelves resistance value and final design temperature are inverse ratio according to claim 1,2,3,4 or 5 described ceramic electric cookers.

7,, it is characterized in that also being provided with on the said electric cooker work timing device according to the described ceramic electric cooker of claim 6.

8,, it is characterized in that also being provided with on the said electric cooker protected by temperature limitation device according to the described ceramic electric cooker of claim 7.

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