CN1364061A - Electric heater - Google Patents

Abstract

A method of reducing the power output of a thick film heater to a predetermined fraction of its maximum power is disclosed. The method comprises applying a series of regular periodic bursts of electrical energy to the heater wherein the bursts are sufficiently short that the face of the heater plate opposite the heating track does not reach an equilibrium temperature. Also disclosed is a method of detecting dry switch-on by applying a lower power at the start of heating and determining whether a threshold rate of temperature rise is exceeded. In a method of calibrating a temperature sensor, the resistance at boiling and at another temperature (the latter e.g. being measured during manufacture) are measured and interpolation or extrapolation used. Other methods for estimating volume, reducing power as a given temperature is approached and detecting scale build-up are also disclosed.

Description

Electric heater

The present invention relates to electric heater, particularly be used for the electric heater of heating liquid and the whole bag of tricks of these heaters of control.

In the field of water heating vessels, use the component heater that is printed with thick film that is installed as the opening in the pedestal of closing this container promptly to become more and more general.Such heater comprises the resistance track on the insulating barrier that is printed on the metallic substrates.One of advantage of thick film heater is the ability of their conduction high watt (watt) density and high general power.

; emerging another important characteristic is by the flexibility that can provide any amount of separation to heat this Heater Design person that track gives, and these heating tracks can have different power and can separately use or be used in combination with another.Therefore for example almost always be designed to be used for simply boil water at the kettle and the water pot of European market, the heating vessel that design for the Far East also usually designs and is used for water is simmered for a long time.Therefore the designer of this utensil can be provided for water being heated to a main high power heating track of boiling and being used for simmering one second low-power track of water in maintenance after this.An example of this layout is disclosed in WO97/04694.

Also know in Millennium M2 kettle a temperature that water is remained on below the boiling.This by constant temperature obtain, promptly power up (energise) for this heater short time when following when definite this water temperature has dropped to a threshold value.Because the high heat capacity of water supposes that heat spreads by water with low relatively speed and low conductivity, so although discontinuous power supply, this mode of heating is also given all water one metastable mean temperatures.

, the applicant has realized that the metastable while of most of temperature maintenance at water, and the transient temperature that contacts the water of this heater surfaces also should be considered.When heater outage, and heat is before temperature descends once more when spreading by water body, and this temperature will be climbed to the normal value that it can arrive and this water is heated to boiling.When this had the whole ideal effects that this water remained on approximately stable temperature, the water that is in heater surfaces was standing to produce the part of the noise of not expecting and is boiling.

Have again, have realized that above-described characteristic up to now such heater is got rid of be used to heat have average than the low-heat diffusion rate, promptly have a lower pyroconductivity and suppressing outside other liquid of big viscosity of convection current, milk for example, even the mean power of a plurality of circulations may be relatively low, this milk still can be burnt by the amount temperature of crossing on heater surface.

When first aspect is seen, the invention provides a kind of method of the power of a thick film heater being exported a predetermined portions (fraction) of the peak power that is reduced to it, described heater has a planar substrates of electric insulation at least one face and is used for a resistance heating trace of described insulating surfaces, described method comprises that the electric flux pulse with the series of rules cycle is applied to described heater, and wherein this pulse is enough short so that the surface of the heater plates opposite with this heating track does not reach an equalization temperature.

From another point of view, the invention provides a kind of firing equipment, this firing equipment comprises a thick film heater and an electric controller, this thick film heater has at least in a planar substrates of a side electric insulation and is used for a resistance heating trace on the described insulating surfaces, the electric flux pulse that this electric controller was arranged as the series of rules cycle is applied to described heater, and wherein this pulse is enough short so that the surface of the heater plates relative with this heating track does not reach an equalization temperature.

Therefore it will be appreciated that, according to the present invention, very short energy pulse is applied to this heater so that facing surfaces, the i.e. surface that contacts with the just heated thing of for example liquid, do not reach the chance of an equalization temperature, if promptly power the temperature that it will reach continuously.The output of the mean power of this heater will depend on this pulse duration and at interval ratio between them certainly, promptly known dutycycle (mark-space ratio).By limiting according to the present invention the absolute duration of this pulse, can reduce widely at the maximum temperature of the area of heating surface experience of this thick film heater.For example, this means that the liquid as water can be heated with a power that reduces, do not boil (noise that therefore any essence also do not take place) and the part can not take place, otherwise this part is boiled and will be taken place.It has also developed the possibility that can't stand other liquid of the power density related with the heater of full power operation with given high power density heater heating, for example milk or soup.In fact, this heater can be used for heating solid or the semisolid such as various food etc.

Person of skill in the art will appreciate that the present invention allows a high power density thick film heater to be converted into the heater with lower-wattage density effectively.Because it when reducing size and therefore reducing this heater cost, allows the even heating by this heater continuously, this is than wherein for example providing a layout of separating the low power density track to have advantage.

The maximum duration that the surface far away that prevents this heater is reached the energy pulse of equilibrium will depend on the thickness and the heat conductivity of this insulating barrier and metallic substrates certainly, and depend on the rated power of this heating track.In a preferred embodiment, the duration of this pulse is more preferably less than 200 milliseconds less than 500 milliseconds, is more preferably less than 100 milliseconds.In certain embodiments, utilized only 20 milliseconds pulse.

Here incite somebody to action almost such a case always, this heater provides an alternating current (A.C.) power supply, the preferably integer circulation of this pulse duration.This makes the beginning of this output pulses and end can be arranged on the place that voltage passes zero line.Owing to switched load (this heater almost completely is an ohmic load) under the zero current condition, this has reduced electromagnetic interference.Therefore preferred maximum impulse duration supposition given above operates on 50 hertz of A.C. main power sources (mains supply) of UK, and corresponds respectively to 25,10,5 and 1 circulations.When using another frequency as 60 hertz, these preferred pulse durations should correspondingly revise.

Be used for any suitable device that electrical power switches to this heater can be used at present preferred TRIAC etc.

Effective minimizing of the power density of a thick film heater provided by the invention is useful in many cases.In special preferred embodiment, this heater is bonded in the liquid heating apparatus.In a preferred embodiment, the power of minimizing is used to operate this liquid heating apparatus so that it preferably is heated to boiling with for example water, and does not produce any recognizable noise basically.Certainly can understand, when a liquid was heated to boiling, this boiling produced some noises inevitably.Therefore, the substantial elimination of noise meant with reference to the stage before all the boiling of liquid takes place.

Can recognize that this layout self is that novelty and creationary is arranged, therefore when from wider aspect, the invention provides the method for temperature of the liquid in a kind of rising one liquid heating apparatus, described method comprises with a kind of like this power powers up for this heater, and does not during heating produce recognizable noise in fact.

The present invention also expands to a liquid heating apparatus and this controller itself that has an electric heater and be arranged to a controller of operating this equipment by this way.

Can arrange this equipment so that operation in this way for good and all.Preferably, when needing peace and quiet heating, the user can select this operator scheme, and also can select a higher power mode to heat with acceleration when not considering noise.This stillness mode only may can be preselected before heating beginning.Preferably it also can be during heating selected.Therefore if a user begins to heat liquid in this equipment with higher-wattage, need then to receive calls, he or she can select stillness mode, has finished or reached the water temperature of expectation up to this telephone relation.Also preferably, the selection of this stillness mode also suppresses the sound that have a mind to be produced by this equipment, as when heating is finished, notify " bang ".

In some preferred embodiments, rule of thumb pre-determine for fear of noise and produce the power be applied on this heater.Can use the constant power rank, but preferably design a minimum noise heating schedule, wherein this power rank is adjusted into when maximizing this power when minimizing heat time heating time, minimizes noise.The applicant has realized that the noise that produces changes during the normal heating of for example water.For example have realized that to apply when for the first time to produce noise hardly when power and this equipment warm, noise increases when heat arrives this water, reduces once more when the convection current in this water begins to take place, and increases up to boiling gradually then.Therefore, apply a predetermined power curve according to a method for optimizing, this power curve is determined so that in the generation that minimizes noise, maximizes this power at set point.

This itself is that novelty and creationary is arranged, therefore from the further aspect of the present invention, include the method for the liquid of a kind of heating in electric heating vessel, comprise with predetermined curve and apply the heater of power to this container, described curve is derived so that in the generation that minimizes noise, maximizes this power at any given time.

The present invention also expands to an electric liquid heating apparatus, comprises being arranged to control device and the described control device itself of operating this equipment by this way.

Alternatively or additionally, this equipment comprises the device of the sound level that detection is producing and is applied to power on this heater to avoid producing the device of any recognizable noise according to the sound level adjustment that is detected.Therefore, if expect that this power can be reduced to initial low value with this equipment of noise level operations that reduces, stably increase then up to the noise that produces on the certain threshold level.This power can be reduced once more slightly then.If determine that once more noise on this threshold value, can further reduce this power then.

Because when it keeps operation on a noise rank that reduces, minimize the heating shared time of this liquid, this layout is useful.It also automatically solves during heating process, particularly this liquid during near bulk boiling with the variation in the tendency of the noise that produces.

This method self that reduces noise is useful, therefore when from one side again, the invention provides a kind of method that in the liquid of heating in the one electric liquid heating apparatus, reduces the generation of noise, comprise the rank of electrical measurement noise and regulate the electrical power that is applied on this element according to measured noise rank.

When from more on the one hand the time, the present invention also provides a kind of electric liquid heating apparatus, comprise that induction works as other electroacoustic sound sensing device of noise level of being produced when this equipment is just heating a liquid and regulate the device of the electrical power on the heater that is applied to this equipment according to the noise rank that is detected.

Can use any electric transducer that can detect sound, for example microphone.The liquid that this sensor can be placed on this equipment receives in the cavity volume, but preferably is positioned at " doing " face of this heater.This makes to produce and becomes easy and help to guarantee reliability.

The sound sensor device can detect whole sound levels, but preferably it is arranged to and only detects more among a small circle a frequency.This helps avoid the insecure function that draws from high ambient noise etc.Therefore, this sound sensor device preferably only sensing be lower than 500 hertz frequency substantially, also preferably be higher than 50 hertz.

Disclosed before another useful especially application that reduces the method for power is the detection of the dried energising (dry switch-on) of a liquid heating apparatus.In a preferred embodiment more particularly, the invention provides a kind of method of a thick film electric heater of operation one liquid heating apparatus, comprising: apply a power that reduces according to a first aspect of the invention to this heater; Whether the speed of determining the temperature rising of this heater is higher or lower than a predetermined threshold value, if and the speed that this temperature raises is lower than this threshold rates, increase the power that is applied, if the speed that the temperature that this detected raises is higher than this threshold rates, then interrupt the power supply of this heater.

Therefore it will be appreciated that,, initially apply a for example lower-wattage of half peak power according to this preferred embodiment.If this equipment normally is full of, the speed that the temperature that caused raises will be relatively low and should be lower than the tripping operation of this threshold value to avoid trouble.If this equipment has been switched on power supply to distribute the heat of generation in its inside under without any the situation of liquid, this temperature that is caused raises and will accelerate significantly.This threshold rates is provided with like this, and promptly it is lower than the speed of doing the rising of energising temperature, and this equipment will interrupt supply of electric power like this.

This is not only a kind of effective ways of doing energising that detect, and be saveall inherently, just can not applied total power because if this equipment does energising, it is low significantly that the temperature that this heater, seal, chamber wall etc. reach before cutting off the electricity supply will apply the total power of equal length time such as fruit.

This layout itself is novel in creative, if do not consider to be used to reduce the method for power, and when when seeing on the one hand again, the invention provides a kind of method of a thick film heater of operation one liquid heating apparatus, comprising: apply a power that reduces to this heater; Whether the speed of determining the temperature rising of this heater is higher or lower than a predetermined threshold value, if and the speed that this temperature raises is lower than this threshold rates, increase the power that is applied, if the speed that the temperature that this detected raises is higher than this threshold rates, then interrupt the power supply of this heater.

The present invention also expands to a liquid heating apparatus, has a thick film heater and a controller and this controller itself that can operate this equipment by this way of the opening of closing on the pedestal.

Whether the speed that temperature raises is higher or lower than determining and can being undertaken by the threshold temperature after seeking the predetermined temperature of obtaining or seek at the fixed time in corresponding threshold time of threshold value.Preferably measure an actual value of temperature increase rate.This value can directly compare with this threshold rates then.

In one embodiment, the total power of this heater is rated for 3 kilowatts, but is reduced to 1.5 kilowatts when powering up for the first time.This threshold value is set at 8 ℃ of s ^-1If, promptly the temperature of this heater raise faster than this, suppose that this heater done energising.

Can for example measure the speed that temperature raises a second at a predetermined period.Can measure temperature in addition raises the shared time of a scheduled volume.Although this implements complicated a little, its usefulness is that the maximum temperature that it allows this plate to be reached effectively is restricted to a predetermined value during dried energising.The temperature of the end of the measurement of expression rising speed even can be set to be same as or be lower than the general operation temperature of this heater.Done energising even this means this equipment, this heater can be not overheated yet.

In some preferred embodiments, if two or all be not exceeded in this threshold value of all occasions, only applying under the flat-out situation, can carry out once with the comparison of this threshold rates more than, if but it all is exceeded in any one occasion, then interrupt power.This is useful guaranteeing that this protection system is avoided the deception that this heater last time used the small amount of liquid of leaving over, and this small amount of liquid may temporarily suppress the speed that temperature raises partly.

When having applied total power, more no longer the needing of the threshold rates that raises with temperature carries out.Preferably, compare simultaneously in that this liquid is heated.This more important thing is because providing further backup under the inaccurate situation of any reason low-power measurement, if be allowed to do under boiling, the situation that for example this equipment is set to keep for a long time seething with excitement at this equipment, it will provide protection.

Even in fact have realized that to the measurement of not carrying out temperature increase rate when having applied total power, initially applying a low-power also is useful in detecting dried energising.This is obtained from following understanding, promptly big instantaneous effect often betide initial heating and therefore the speed that raises of temperature may for it, rise and fall too big and can not be as doing a useful indicator of switching in this stage.Yet minimizing the benefit of doing the temperature that reaches during the energising still keeps.

Therefore, when seeing on the one hand again, the invention provides a kind of method of operation one electric heating vessel, comprise: apply the heater of the power that reduces of a predetermined period to this container, whether this after-applied higher-wattage also determines speed that the temperature of this heater raises greater than a predetermined threshold value, and if the speed that raises of this temperature be higher than this threshold rates, interrupt the power supply of this heater, if it is lower than this threshold rates, then continue this liquid of heating.

The present invention also expands to a liquid heating apparatus, comprises being arranged to control device and the described control device itself of operating this equipment by this way.

The higher-wattage of this aspect total power preferably according to the present invention.This is advantageously, be used for determining that one does threshold rates that temperature that whether energising taken place raises and can be arranged on and be suitable for a flat-out rank because it means, and therefore identical value can be used to detect.

In the preferred embodiment in this aspect of the invention, for example 1.5 kilowatts lower-wattage is applied in a predetermined period of time, and 3 seconds for example, before for example applying 3 kilowatts total power, power interrupts a predetermined period automatically, for example 2 seconds then.This equipment is arranged to and determines whether the speed that temperature raises surpasses 6 ℃ of s then ^-1Threshold value.Have, in order to determine whether to allow to do boiling, this threshold value is monitored by the operation of this equipment again.

As mentioned above, preferably measure the actual value of the speed of temperature rising.In order to protect this heater to avoid owing to do overheated that energising causes, simply with this actual value and a threshold rates comparison with definite it be height or low.The applicant further recognizes, the value of the speed that temperature raises can be used to provide the indication of the volume of just heated water.More particularly, this volume can be by considering that power is exported and the specific heat capacity of the liquid of for example water is calculated.Can also be used to carrying out the corrigendum of the thermal loss of the efficient of this heater that can determine by experience and this liquid.

Will recognize that, this notion itself is novel in creative, therefore from another point of view, the invention provides a kind of estimation method of the volume of the liquid by the heated known thermal capacity of an electric liquid heating apparatus, described method comprises: apply power to the heater of described equipment, on a preset time, measure described liquid temperature rising and according to this time, thermal capacity with offer the described volume of energy calculation of total of this heater at described time durations.

The present invention also expands to a liquid heating apparatus, comprises the control device and the described control device itself that are arranged to by aforesaid operations.

It will be appreciated that according to this aspect of the invention, the speed of this fluid temperature raises and is used to calculate this liquid volume.This can use with being used to detect and do the same rate calculated of energising, but preferably carries out a decouples computation, for example through a longer cycle so that return a more accurate number.In a concrete example, use thermometric one average (rolling of upgrading once each second is of making through 5 seconds average) to be used for determining to do the calculating of energising purpose, but the calculating that is used for volume will be through 20 seconds (also being to upgrade each second).

Temperature survey can directly be carried out, and for example contacts this liquid with right sensors.But preferably measure this temperature by this heater indirectly.Be electrically connected with it because it allows sensor to keep dry and be easier to, it is more convenient that this point seems.This sensor even can for example avoid doing the identical of energising with being used to protect this heater.Under the situation of thick film heater, this temperature sensor separates according to whether making things convenient for can be printed in this heater substrate or with it.

Preferably, if the volume that is detected is higher than a predeterminated level, if promptly this equipment is full of by excessive, this equipment is arranged to the power that reduces to be applied to this heater.This is helping to be avoided to have clearly benefit with excessive being full of aspect dangerous that the hot water that is associated spills etc.Preferably give user's one caution signal, if so that it is full of by excessive, he knows and pours out some liquid.

Even have realized that this equipment is not full of by excessive, the volume of knowing liquid also is useful.In a preferred embodiment, if liquid volume in a preset range of maximum magnitude, when this liquid near when boiling, be reduced to the power of this heater.This means if this equipment be full of or near being full of, the situation that it will it be filled such as fruit is seethed with excitement lightlyer.This means approaching lightlyer boiling, and therefore help prevention boiling water when this equipment is relatively expired to spill by mouth of pipe danger.Therefore, the needs of the upper space that has reduced to be used to provide a safety to avoid spilling etc.Because it means that the size of this equipment can reduce for a given liquid capacity, this obviously is useful.This is economical from the viewpoint of material cost not only, and it has strengthened client's attraction of outward appearance and this equipment.

Reducing power the burden of PCU Power Conditioning Unit will be reduced on the higher general operation temperature that interrelates with boiling, this device usually is a solid-state device of TRIAC for example, and the environment temperature that generally in this equipment, experiences of restriction, it for example has the useful hint to the rated value of electronic unit.

In fact, this notion does not rely on the volume according to the detected liquid of the method for describing before, and this volume can pass through any suitable device such as a floating thing, or detected by the weight of measuring it.Therefore, when when seeing on the other hand again, the invention provides a kind of method of operation one electric liquid heating apparatus, comprise: whether the liquid volume that detects in this equipment is higher than a predetermined threshold, be heated at this liquid and apply one first power during first heating period of a medium temperature and apply one second lower-wattage to this liquid be heated to one second heating period of boiling at this liquid during.

The present invention also expands to an electric liquid heating apparatus, comprises being arranged to control device and the described control device itself of operating this equipment by this way.

The reducing and can realize of this power with any mode easily, but preferably realize according to a first aspect of the present invention.This second lower-wattage can be for fixed value and whenever applying that this threshold value volume is exceeded.In addition, can use a slip to reduce so that the amount of this power reduction depends on, for example in proportion to, this closes on specific maximum volume.

Also have realized that by knowing liquid volume in this equipment and the power rating that also is applied to this heater, can estimate that this liquid is heated to one gives the fixed temperature time that (for example boiling) spent by supervision.Therefore, preferably this equipment comprises that estimation will reach the device of a preset temperature with the time of cost.This time preferably is shown to this user, and preferably whole this heating process is promptly as a timer reciprocal.

Be used to estimate the volume that needs heat time heating time estimate can as early a disclosed low-power carry out between the starting period.Same temperature increase rate can be between the normal starting period, or preferably is determined in the later phases of heating, and it advantageously can avoid the mistake that produces from initial instantaneous influence.In fact, this volume can be determined by any suitable replaceable method of for example weight detecting recited above etc.Therefore it will be appreciated that, estimating to reach one, to give the notion of the time of fixed temperature itself be novel in creative, therefore when when seeing on the other hand again, the invention provides the time method that a kind of estimation is heated to the liquid of the known thermal capacity held in the liquid heating apparatus one predetermined temperature, comprise: the volume of estimating liquid in this equipment, determine to be applied to the power quantity of the heater of this equipment, and determine the needed time according to this thermal capacity, volume with the gross energy that applies.

The present invention also expands to a liquid heating apparatus, comprises being arranged to control device and the described control device itself of operating this equipment by this way.

The estimation of this required time can only be carried out once, for example in heating at first.Preferably, during heating upgrade it.When this user can during heating revise power rating, when for example selecting early disclosed " peace and quiet " pattern, this is useful especially.

The above-mentioned each side according to the present invention estimates to calculate the time of giving fixed temperature that reaches from the volume of the liquid this equipment, and in some preferred embodiments, the estimation of this liquid volume is the rate calculations that raises from temperature.Have realized that speed, can direct estimation reach one to the time estimation of fixed temperature with cost by inferring that temperature raises.Therefore from wider aspect, the invention provides the time method that liquid that a kind of estimation held reaches a predetermined temperature in a liquid heating apparatus, comprising: heat this liquid; Measure the speed of temperature rising and infer the described speed of described predetermined temperature.

The present invention also expands to a liquid heating apparatus, comprises being arranged to control device and the described control device itself of operating this equipment by this way.

Only a single for example initial estimation can be carried out once more, but the estimation of preferably when the power of the heater that is applied to this equipment changes, making amendment at least.The time of this estimation preferably is shown to this user with the form of timer reciprocal.

Whichsoever method is used to reach an estimation of giving the time of fixed temperature, and according to another invention disclosed herein, this time is estimated to be used to be set at a set time that power is applied to this heater.More specifically, the present invention includes a kind of operation one electric liquid heating apparatus and be heated to the method for a predetermined temperature with the liquid that will wherein be held, this method comprises: estimation is heated to the time of described temperature with cost with this liquid; Estimate definition one fixing heat time heating time based on described time, and apply the power of described fixedly heat time heating time, after this interrupt or be reduced to the power of this heater.

Although it is comparatively simple that this notion seems, but all religious doctrines before of it and this area are opposite, if promptly the heater in a heating vessel will automatically cut out, this should be by obtaining this liquid what happens via wherein the temperature and the generation measurement and the sensing of gas passively.Then, reach desired temperatures when, when for example seething with excitement, this passive supervision is used to detect.Now suggestion heating one early the stage monitor the certain parameter of this liquid, use these predictions when will reach this temperature, predict that according to this actual fixed should heat time heating time then.Because it means the temperature sensor that need not provide precise results when promoting temperature, has promptly reduced the needed dynamic range of temperature sensor, this is favourable.This can reduce expense in some cases, for example by making scale easier.

This notion can be used in any temperature that liquid just is being heated to, but the most suitable when liquid is heated to boiling.Its reason at first is that the requirement of measuring near the temperature the boiling has increased the essential dynamic range of maximum of sensor, yet the more important thing is, by measuring the temperature of a liquid or by detecting steam, accurately detects generally difficulty/costliness relatively of boiling., according to the present invention who advises above, the needs that detect boiling have been got rid of fully.

Have, the applicant has realized that additional benefits of the present invention is again, estimated boiling time can be prolonged intentionally.This is inevitably measuring under coarse situation, has not only guaranteed the actual generation of boiling, also can make boiling continue a preset time length.In order to provide the effects of the boiling of rolling in several seconds that expectation discovered by the consumer, this may only be the time in several seconds, and particularly at UK, perhaps it may be a more longer time cycle, for example with water sterilization.At least in situation after a while, that the boiling time of prolongation preferably can preset and preferably with a power that reduces, between preferably flat-out 5% and 15%.

Disclosed herein as well is a further invention.

The present invention relates to be used for the controller of electric liquid heating apparatus, be specifically related to be used to measure the method and apparatus of just heated liquid.

Along with among thick film heater and the consumer for the functional appearance of liking that increases of all home appliances expansion, reappear to a certain extent after out in the cold for the former because consideration of cost of the interest of the electronic controller of heating vessel.

One of problem of electronic controller provide a cost effectively, suitable electronic sensor accurately.In the prior art, for the temperature of sensor heaters plate, sensing fluid temperature or protection heater itself are not overheated indirectly, have advised using the additional sensor of printing the track form with a positive temperature resistor coefficient.Unfortunately, it has been found in practice that because in the ink (ink) that uses or the changeability in the printing process itself great changes that in the resistance of these sensor tracks, taken place.In order to overcome this point, required the uneconomic manual scale of each heater.

The discrete electrical heat regulator that utilization has an enough tight tolerance is overcoming this problem, but these are relatively costly.On the contrary, more cheap parts trend towards requiring the scale done with the method for printing track.

Therefore, its purpose is to provide a kind of device that relaxes above-mentioned shortcoming at least in part.

From another aspect, the invention provides the method for scale of heat sensor of temperature that a kind of demarcation is arranged to the substrate of the thick film heater of measuring a liquid heating apparatus, described method comprises: at the resistance of one first temperature place record sensor, the liquid that heats in this equipment arrives boiling, write down the resistance of described sensor, and after this use described two resistance to calculate the temperature of this sensor at each temperature place below boiling by interpolation or extrapolation.

Therefore it will be appreciated that according to this aspect of the invention, the resistance of this sensor is measured at the temperature place of two separation, and the result is used to demarcate the scale of this sensor to provide temperature survey at other temperature place.First temperature can be higher than second temperature (temperature of measuring) when the liquid boiling in the container, for example behind the face of overglazing, when after being heated, carry out first resistance measurement when thick film heater is cooling off.This is specifically applicable to the situation that is printed on the heater bases at this sensor.

This first temperature preferably is lower than second temperature and preferably approximately is room temperature.This means that two reference resistances are measured respectively holding of about working range of this sensor.

In order to demarcate the scale of this sensor, first temperature must be measured certainly independently.Therefore, this can carry out easily at production period.For example can use thermocouple etc.

When being in boiling temperature, measures the liquid in the container second temperature.This temperature also can be measured with independent device, but preferably from container the fact of the actual boiling of liquid is inferred.The a variety of methods that can measure are arranged.For example, can detect the injection of steam or carry out the visual inspection of boiling by the operator.Be more preferably, the speed by variations in temperature does not detect boiling by the temperature of reality to use sensor itself, promptly suppose the exact scale regardless of sensor, when the liquid boiling in the container, the time dependent speed of its resistance will trend towards zero.This has been found appearance in practice.In a concrete preferred embodiment, by with the tangent line of temperature curve to return be extrapolated to about this heating process zero-time with the accounting temperature axle on corresponding intersection point determine to seethe with excitement and the rate of change of accident amount temperature itself.In other words, if the speed that temperature raises is constant always, the suitable initial temperature that then will be elevated to present temperature is monitored.This value will start from the actual initial temperature of this heater and be elevated to final boiling temperature.The threshold value that for example defines 80 ℃ is for seething with excitement at first.

In addition, suppose that container is filled to its heap(ed) capacity and then heater is powered up a time enough to guarantee that the energy of this amount has entered this liquid of heating at least, can infer boiling simply by calculating the required energy that enters this liquid.

The applicant has realized that as aforesaid result the second scale step can be carried out by suitably disposing liquid heating apparatus itself.Though do not realize, this has opened the possibility that the second scale step is for example carried out by the consumer after dispatching from the factory.Produce in the factory and time of calibrated scale because it has minimized, so saved cost, so this is favourable.Have again, it has alleviated otherwise will be in any problem that takes place to cause under the following situation, promptly owing to can the final assembling of liquid heating apparatus after, carry out meticulous demarcation, with the become separation and not matching of a concrete controller of the transducer calibration on the concrete heater.These problems cause probably when this sensor is disposed in a container part that separates, and this control device is disposed in the pedestal of a no electric wire of this equipment.

Therefore, this feature itself is novel in creative, and from second aspect, the invention provides a kind of liquid heating apparatus, comprise: electronic-controlled installation, this electronic-controlled installation comprises a temperature sensor of partly having been demarcated, and described control device is arranged to the liquid in the container is heated to boiling, measures the resistance of described sensor and according to the scale of this sensor of resistance calibration of described measurement when liquid boiling.

In a preferred embodiment, the control device of this equipment is arranged in and carries out this demarcating steps when the consumer uses for the first time.Therefore, if infer boiling from the quantity of input energy, the consumer may be instructed to this equipment is filled to its heap(ed) capacity when using for the first time.Certainly, boil the required amount of energy of all told and also will boil a less quantity.

If this user for the first time or stoped the generation of boiling in the follow-up use, for example closes this equipment or its pedestal from it is removed under the situation of no electric wire utensil, then preferably this equipment reattempts this demarcating steps of execution when next operation.

According to the equipment of method for optimizing and the application of the invention, carry out the second scale step effectively by the user.Therefore, this user must be with not operated this equipment at least once by the sensor of complete scale., will usually have can be with the nominal preassignment temperature relation formula from its temperature relation formula of the measurement carried out in first temperature extrapolation for this sensor.Although this may be inaccurate to a certain extent, it will be enough accurately to guarantee this device security, and promptly sensor in a preferred embodiment can be in its margin of tolerance difference normal running and dried energising/dried boiling.

Preferably measure temperature below the boiling by the interpolation of the resistance measured respectively in first temperature and boiling place.The applicant has realized that the temperature of boiling needn't accurately mate with its theoretical value, and for example water is 100 ℃.For example, residing latitude takes place and will influence its temperature in boiling.Therefore, indicated medium temperature is different from the actual physical value.Because these medium temperatures are selected according to he individual's hobby by the user probably, absolute temperature is not important especially.The more important thing is that at a given latitude, a selected temperature is with relative repeating.

The form of this temperature relation formula, the constant attribute that draws from the resistance of two scale temperature will depend on the type of employed temperature sensor.If for example use the electro-hot regulator of positive temperature coefficient (PTC), this temperature relation formula is the linear relation of approaching following form usually:

R=R ₀+ AT A here is the coefficient of resistance temperature.In this case, therefore the scale temperature is used to set up R ₀Each value with A.

Under the preferable case of negative temperature coefficient electro-hot regulator, this relational expression generally is an exponential relationship formula of following form:

R＝R ₀-e ^-(BT)

Here B is that a constant relevant with so-called beta (bata) value of electro-hot regulator (depends on measured temperature R ₀Exact relationship).

Require to demarcate to determine above-mentioned constant although have been found that available practical electro-hot regulator, the form of their temperature relation formula promptly is respectively linearity and index, also keeps enough degrees of accuracy.

As previously mentioned, can use the heat sensor of the printing track form of suitable responsive to temperature ink.; preferably use the discrete electrical heat regulator that has good thermo-contact with heater now; discrete electrical heat regulator with negative temperature coefficient of resistance preferably is because therefore these variations that have a greater amount level with respect to temperature and resistance provide more accurate result.

Boiling scale step can only be carried out once when for example using for the first time.In a preferred embodiment, the step that the liquid in the equipment is heated to the resistance of boiling and measuring transducer is repeated, and preferably is used to whenever boil liquid at this equipment., according to this feature, no longer time demarcate this sensor and its resistance value and original scale value compared in boiling place.This process will show any increase when the temperature of this sensor during at boiling point of the liquid in the container.These increases usually are to cause that by the scale buildup in the heater (build-up of scale) it means that As time goes on heater will usually trend towards becoming hotter.Very clear, it is unimportant whether the resistance of whether relatively demarcating and measuring or they are converted to corresponding temperature.

Be preferably this difference one threshold value is set, if so that this threshold value is exceeded, this user can for example be warned with audible or observable indication and note this scale buildup, takes remedial action to allow this user, is about to this equipment scale removal.In addition, this equipment preferably is arranged under the situation that this threshold value is exceeded and operates in the mode of revising.This control is not only to power up to heater.But preferably it is arranged to and reduces the power that applied.

This itself is novel in favourable, therefore when when further aspect is seen, the invention provides the method that the incrustation scale of a kind of detection in a liquid heating apparatus gathers, comprise: the temperature of when the liquid boiling in this container, measuring the heater of this equipment, if more described temperature and reference temperature and described temperature reduce to be applied to the power of described heater than the big predetermined threshold of this reference temperature.

The present invention also expands to a liquid heating apparatus, comprises being arranged to electronic-controlled installation and the described control device itself of operating this equipment by this way.

Therefore it will be appreciated that, according to this aspect of the invention,, then reduce the power of heater if detect scale buildup.This is useful, in a preferred embodiment, because it has reduced the maximum temperature that obtained by heater in these cases, therefore avoided fault owing to the overheated heater that causes, and reduced the remainder of this equipment, the temperature that for example control, sealing, chamber wall etc. is experienced.Have again, when scale buildup takes place,, can avoid loaded down with trivial details operation such as the heater protecting mechanism of the self-protection feature of maximum temperature monitor, bimetal regulator or heater itself by reducing the general running temperature of heater.

Can be reduced to the power of heater by any available method.But preferably reduce according to a first aspect of the present invention disclosed herein.This is useful, because it has minimized the transient temperature of heater experience, and has therefore strengthened when detecting incrustation scale by reducing the obtained benefit of power.

Although considering this fact, the time that liquid spent in this equipment of promptly boiling increases gradually and this may be carry out under the situation of enough indications of scale removal, possibility is unnecessary, but preferably needs an audible or observable indication of scale removal to the user.

Threshold value is preferably between 5 ℃ and 10 ℃ preferably less than 10 ℃.

Reducing of power can be a single step-size change, but preferably to depend on, for example in proportion to, the less step-length that the temperature of boiling surpasses the quantity of threshold value is reduced.The constant that proportionality therefore preferably is set is so that from the complete rupturing duty of the maximum difference of threshold value.

Mention indirectly as top because the thermo-lag that produces from the hot material of heater etc., by the temperature of sensor senses can greater than the temperature of liquid itself some.Because not influence of the absolute value of measured temperature then, only be used to boil under the situation of liquid at this equipment, above-mentioned difference is important hardly, unless but to be corrected, it will influence the degree of accuracy that will allow the user to specify the embodiment of a temperature that is lower than the boiling that liquid is heated to.It also will influence the degree of accuracy of any demonstration of Current Temperatures.These will increase the error in the accounting temperature from any systematic error that draws than the more lower boiling influence of high latitude discussed above.

In simple embodiment, can assumed temperature lagging behind be a constant, and therefore moves as negative bias and be applied to by the measured temperature of sensor.Although this is to provide correct relatively result's relatively effectively to suppose, but the applicant has realized that when reaching desired temperatures, by reducing to be applied to the power on the heater, the temperature of institute's sensing has more correctly reflected the temperature of liquid, and have been found that this is than using constant offset can provide more accurate result.

Do not consider to be used for the method for calibration sensor, this notion itself is novel in creative, and when when further aspect is seen, the invention provides the method that a liquid heating apparatus that a kind of use has an electronic-controlled installation is heated to a liquid predetermined temperature, this method comprises: apply the heater of first power to described equipment, determine the time of the temperature of this liquid near preferred temperature, and after this with power reduction to one second lower-wattage that applied up to reaching described desired temperatures.

The present invention also expands to a liquid heating apparatus, comprises being arranged to electronic-controlled installation and the described control device itself of operating this equipment by this way.

Except allowing a desired temperatures accurately obtained, this feature has provided avoids the heater benefit of recognizing of outage suddenly.This point is very significant to the high power heater that trends towards producing a large amount of noises in heating.According to the present invention, heating will stop gradually.

Power what reduce can be the variation of single step-length, but preferably it is reduced with a series of smaller step size, these less step-lengths depend on, for example approximately in proportion to, to the distance of expectation temperature.In other words, the use feedback control loop is controlled the power when approaching preferred temperature.

Be preferably in and determine to apply a skew when fluid temperature approaches desired temperatures,, just directly monitor measured temperature in case power is reduced.

Do not specify the type of heater in the description in front, preferably use plane heater, preferably thick film heater.Because the thick film heater that uses in hot-water bottle or jar has become common, this heater can comprise the metallic substrates that scribbles a glass ceramics insulating barrier on it.In addition, can use other type and the structure of thick film heater.

Method of the present invention and liquid heating apparatus can use such as the pure hardware unit of discreet component or hard wire logic door and realize.In addition, the present invention can use part software to realize at least, for example computer program.Therefore, when when further aspect is seen, the invention provides computer software, special configuration is the above-mentioned method of execution when be encased in data processing equipment.

Have again, the device of recognizing appointment in the equipment of the present invention can be comprised simply that special configuration is to carry out the computer software of above-mentioned method when being encased in data processing equipment.

The present invention also expands to a carrier that comprises such software, when being used to operate the controller of an electric liquid heating apparatus that is used to comprise a digital microprocessor, this carrier combines with described microprocessor, makes described liquid heating apparatus carry out each step of method of the present invention.This carrier can be a physical storage medium, such as rom chip, CD ROM or disk (disk), maybe can be such as the signal of telecommunication on the electric wire, optical signal or from the radio signal of remote-control device.In a preferred embodiment, an Electrically Erasable Read Only Memory that for example provides on a microprocessor (EEPROM) is provided this carrier.

To further recognize, be not that institute of the present invention need therefore from wider aspect, the invention provides computer software by software performing in steps, and this software is installed on the carrier, is used for carrying out at least one step of each step of said method.Similarly, not that all devices of appointment all need to comprise computer software in equipment of the present invention, therefore in general preferable case, it is at least one that comprises in these devices of computer software.

To use example and embodiment to describe particular aspects of the present invention now.Example 1

Only by the mode of example, with reference to accompanying drawing, this example adopts the form of computer simulation of the embodiment of one aspect of the invention, these accompanying drawings are output patterns of the simulation of thick film heater, wherein:

Fig. 1 is the figure of input power curve of 50% known method of mean power that expression will the be applied to heater peak power that is reduced to it;

Fig. 2 is the output power curve on heater plates opposite of input curve of expression corresponding diagram 1 and the figure of corresponding temperature curve;

Fig. 3 is the figure of input power curve of the method according to this invention of the power reduction to 50% that expression will apply;

Fig. 4 is the power output of input of expression corresponding diagram 3 and the figure of temperature curve;

Fig. 5 is the figure similar to Fig. 3 of expression power reduction to 10%; With

Fig. 6 is the figure of expression corresponding to the output of Fig. 5.

Set up a computer model and with simulation various input power states are applied to adding of heater plates bottom The effect of the liquid contact surface of hot orbit. For the purpose of simulating, suppose thick film heater be one not Rust steel square position, 100 millimeters of diameters, thick 0.5 millimeter, 0.0322 kilogram of quality and specific thermal capacitance Amount is 500Jkg^-1K ^-1。

The power density rated value of heating track is set to 60Wcm^-2 The initial temperature setting of plate and liquid It is 100 ℃. For the sake of simplicity, suppose that the temperature of liquid keeps constant, and ignore the thickness that passes plate Thermograde. The convective heat transfer coefficient of supposing liquid is 2Wcm^-1K ^-1。

As shown in Figure 1, with 60Wcm ^-2One second output pulses square wave series be applied to heater, to simulate known heating vessel method of operating.Interval between each pulse also was 1 second, had therefore provided 50% dutycycle.Therefore the R.M.S. of this power rating or the suitable thermal effect that adds are 30Wcm ^-2Fig. 2 represents that the opposite of this plate is the effect of liquid contact surface.Figure line A is with Wcm ^-2The power output of expression, figure line B is the corresponding temperature with ℃ expression.Can be clear that power output and temperature raise during 1/4th sharp at first of a second, it is balanced that each pulse roughly reached in 0.5 second.It will be appreciated that, reach and the temperature that keeps approximately is 130 ℃, and whole 60Wcm ^-2Be wasted at least half pulse.

Fig. 3 represents according to input power state of the present invention.As Fig. 1, this is the square-wave pulse chain of one 50% dutycycle, and amplitude is 60Wcm ^-2And R.M.S. power is 30Wcm ^-2In this example, pulse length only is 0.02 second corresponding to single whole major cycles.As seen from Figure 4, this obviously simple effect of revising is theatrical.The lasting cycle of the weak point of pulse means that power output is (with Wcm ^-2Figure line C for unit) and temperature (℃ to be the figure line D of unit) reach equilibrium value never as being reached in they former situations.Therefore with the 60Wcm of former situation ^-2Compare peak power output and reached 35Wcm ^-2Similarly, compare maximum temperature with 130 ℃ of former situation and only approximately reach 115 ℃.Therefore, although the effect of average in each case heating is identical, i.e. 30Wcm ^-2R.M.S., but in one situation of back, for example milk can not be burnt when heating, and the 60Wcm that in last situation, is experienced ^-2Be enough to it is burnt.

Similarly, the tendency that boil the part that the maximum power density that reduces has reduced to take place on the surface of heater between the period of heating widely, and the therefore corresponding noise that produces that reduced.For example, have been found that power reduction arrive maximum 3 kilowatts 20%, promptly realize surpassing 6 decibels reducing, thereby even in the background in quiet room, also the sound of emission be reduced to inaudible rank.

But Fig. 5 representation class is similar to Fig. 3 has 10% dutycycle, i.e. 6Wcm ^-2R.M.S. input power state.Its effect is illustrated among Fig. 6.It will be appreciated that peak power output and temperature even further be reduced to about 12Wcm respectively ^-2With 107 ℃.

Opposite, if being modified to, the input of the power of Fig. 1 provides identical R.M.S. power, promptly by the interval being increased to 9 seconds, because the equilibrium that impulse duration reaches in a second, peak power output and temperature are with unaffected.

It should be appreciated by those skilled in the art that example described above can make amendment within the scope of the invention in many aspects, and they only provide illustrations.Specifically, these simulations by idealized but also be enough reality with the characteristic feature of proof the present invention above prior art.

Selecting 100 ℃ numeral only is in order to guarantee that this temperature can clearly draw with the numerical scale identical with power output as the initial plate temperature.A more real value may be 80 ℃, and in this case, the temperature of this plate can surpass 100 ℃ in the method for prior art, causes that therefore the part boils, but can not take place in the method according to the invention.

Have again, because other reason, such as with the generation of electromagnetic interference with to the potential problems of the relevant requirement of the excessive influence of household power supply, the ideal value of using during the actual value of using in these examples is not necessarily put into practice.Therefore, with when not setting up balanced notion, those skilled in the art may need suitably to revise employed value at power that reservation applies enough weak points.Example 2

Make a thick film electric heater and positive temperature coefficient (PTC) electro-hot regulator (thermistor) is attached to this heater so that be in the good thermo-contact according to known technology.Whole assembly is allowed to cool to room temperature.Accurately measure the temperature T that it is just experiencing at use one thermocouple ₁The time, use a precision resister measurement mechanism (itself being known) to measure the resistance R of electro-hot regulator ₁Then, heater and sensor unit are mounted in the kettle and are sold a consumer.

When operating for the first time, the control device of this kettle is arranged to and enters calibration mode.The user is instructed to kettle is filled water, and opening power also allows it boil.Then, this control device apply power to this element up to sensing boiling by the resistance of measuring electro-hot regulator.Then, use the speed of this resistance variations to determine the time that the water in the container seethes with excitement.

In case the water boiling is just cut off the power supply heater.Allow to set up after 2 seconds in addition of thermal balance, measure the resistance R of electro-hot regulator by control device ₂Assumed temperature T ₂It is 100 ℃.Following then calculated resistance temperature coefficient:

C _TR＝(R ₂-R ₁)/(T ₂-T ₁)

Now, kettle can normal running with displays temperature in heating and/or during will being heated to a desired temperatures.Current temperature is by T _X=C _TR* (R _X-R ₁)+T ₁Provide, here R _XBe the resistance of current electro-hot regulator.

When this kettle is set to boil water once more, temperature when measuring boiling and and T ₂Promptly 100 ℃ compare.At first this temperature should be near 100 ℃, but when incrusted deposit, the temperature during boiling can raise.If the boiling temperature by electro-hot regulator induction surpasses 105 ℃, on a user display, provide an alert message, and provide this kettle of indication user should be by the warning tones of scale removal.Have again,, the power that is applied on the heater is reduced from its maximum according to the quantity that surpasses 105 ℃ value.If the temperature of heater surpasses 200 ℃, be zero with power reduction.

Those skilled in the art only will recognize that purpose for the purpose of illustration provides above-mentioned example, and many variations are possible within the scope of the invention.For example, two demarcating steps can be carried out in factory.

Have again,, in example, used PTC electro-hot regulator with a linear temperature relational expression for simple purpose.Use the NTC electro-hot regulator that has index temperature relation formula if replace, will need correspondingly to revise algebraic manipulation.

Claims (41)

1. the method for a predetermined portions of a peak power that the output of the power of a thick film heater is reduced to it, described heater has a planar substrates and a resistance heating trace that is applied on the described insulating surfaces of electric insulation at least one face, described method comprises that the electric flux pulse with the series of rules cycle is applied to described heater, to such an extent as to wherein the surface of these pulses heater plates that enough weak point is relative with this heating track does not reach an equalization temperature.

2. the method for claim 1, the duration of wherein said pulse is more preferably less than 200 milliseconds less than 500 milliseconds, is more preferably less than 100 milliseconds.

3. method as claimed in claim 1 or 2, wherein this pulse duration is the integral multiple of A.C. circulation.

4. the method for the thick film electric heater of operation one liquid heating apparatus comprises: apply a power that reduces to this heater according to claim 1,2 or 3 described methods; Determine that speed that the temperature of this heater raises is higher than or is lower than a predetermined threshold value; And if the speed that this temperature raises is lower than this threshold rates, increase the power that is applied, if but the speed that the temperature that this detected raises is higher than this threshold rates, then interrupt the power supply of this heater.

5. the method for the thick film heater of operation one liquid heating apparatus comprises: apply a power that reduces to this heater; Determine that speed that the temperature of this heater raises is higher than or is lower than a predetermined threshold value; And if the speed that this temperature raises is lower than this threshold rates, increase the power that is applied, if but the speed that the temperature that this detected raises is higher than this threshold rates, then interrupt the power supply of this heater.

6. as claim 4 or 5 described methods, comprise that measuring this temperature raises the shared time of a scheduled volume.

7. as claim 4,5 or 6 described methods, comprise and repeat described following steps: determine that speed that this temperature raises is higher than or is lower than a threshold value; And if only this threshold value surpasses described definite both or all, increases the power that is applied,, then interrupt described power if described threshold value has surpassed described definite any one.

8. as the arbitrary described method of claim 4 to 7, comprise making and describedly determine continuously.

9. the method for operation one an electric heating vessel comprises: a power that reduces is applied to heater one predetermined period of this container, and this after-applied higher-wattage also determines whether the speed that the temperature of this heater raises is higher than a predetermined threshold value; And if the speed that this temperature raises is higher than this threshold rates, then interrupt the power of this heater, if it is lower than this threshold rates, continue this liquid of heating.

10. as the arbitrary described method of claim 4 to 9, comprise increasing described power to peak power.

11., comprise that the speed of using described temperature rising is to determine the volume of the liquid in the described heating vessel as the arbitrary described method of claim 4 to 10.

12. an estimation is the method for the volume of the liquid of the known thermal capacity by an electric liquid heating apparatus heating, described method comprises: apply the heater of power to described equipment, on a preset time, measure the rising of the temperature of described liquid, and according to this time, thermal capacity with offer the described volume of energy calculation of total of this heater at described time durations.

13. method as claimed in claim 12 comprises the temperature of measuring described liquid by this heater.

14. as claim 11,12 or 13 described methods, comprise, reduce to be applied to the power of this heater if the volume that is detected is higher than an intended level.

15. as the arbitrary described method of claim 11 to 14, comprise when the approaching boiling of the liquid in the container, reduce to be applied to the power of this heater.

16. the method for operation one an electric liquid heating apparatus, comprise: whether the liquid volume that detects in this equipment is higher than a predetermined threshold, be heated at this liquid and apply one first power during first heating period of a medium temperature and apply one second lower-wattage to this liquid be heated to second heating period of boiling at this liquid during.

17. method as claimed in claim 16 comprises the power that uses claim 1,2 or 3 described methods to reduce this heater.

18., comprise that the liquid of estimating in the container reaches the shared time of a preset temperature as the arbitrary described method of claim 4 to 17.

19. an estimation is heated to the liquid of the known thermal capacity held in the liquid heating apparatus time method of one predetermined temperature, comprise: the volume of estimating liquid in this equipment, determine to be applied to the power quantity of the heater of this equipment, and determine the needed time according to this thermal capacity, volume with the gross energy that applies.

20., comprise and during heating upgrade described estimation as claim 18 or 19 described methods.

21., comprise and use this time to estimate so that a set time that power is applied to this heater to be set as claim 18,19 or 20 described methods.

22. operation one an electric liquid heating apparatus is heated to the method for a predetermined temperature with liquid that will wherein be held, comprising: estimation is heated to the time of described temperature with cost with this liquid; Estimate definition one fixing heat time heating time based on described time, and power is applied described fixedly heat time heating time, after this interrupt or be reduced to the power of this heater.

23. method as claimed in claim 22, wherein said predetermined temperature is corresponding to the boiling of the liquid in this container.

24. the method for heating one liquid, comprise: provide as 1,2 or 3 described thick film heaters to a heating vessel, and, promptly heat the liquid in this container fully and do not produce any recognizable noise with the described heater of such power operation.

25. method as claimed in claim 24 comprises applying a predetermined power curve that this power curve is determined so that in the generation that minimizes noise, maximizes this power at set point.

26. a demarcation is arranged to the method for scale of heat sensor of temperature of the substrate of the thick film heater of measuring a liquid heating apparatus, described method comprises: at the resistance of one first temperature place record sensor, the liquid that heats in this equipment arrives boiling, write down the resistance of described sensor, and after this use described two resistance to calculate the temperature of this sensor at each temperature place below boiling by interpolation or extrapolation.

27. method as claimed in claim 26, wherein said first temperature is lower than this second temperature.

28., comprise that the rate temperature change that uses this sensor detects boiling as claim 26 or 27 described methods.

29. one kind itself is arranged to the liquid heating apparatus of implementing claim 26,27 or 28 method.

30. liquid heating apparatus, comprise: electronic-controlled installation, this electronic-controlled installation comprises a temperature sensor of partly having been demarcated, described control device is arranged to the liquid in the container is heated to boiling, when liquid boiling, measure the resistance of described sensor, and according to the scale of this sensor of resistance calibration of described measurement.

31. as claim 29 or 30 described liquid heating apparatus, wherein one or this control device be arranged in and carry out this demarcating steps when the consumer uses this equipment for the first time.

32. as the arbitrary described method and apparatus of claim 26 to 31, wherein said sensor comprises the electro-hot regulator with negative temperature coefficient of resistance.

33. as claim 26,27 or 28 described methods, comprise repeating step: measure the resistance of described sensor and compare with the measured value of raw sensor in boiling place, so that determine whether between is variant, this difference indication incrustation scale has accumulated on this heater.

34. method as claimed in claim 33 comprises:, reduce to be applied to the power of this heater if this difference is arranged.

35. the method that the incrustation scale of a detection in a liquid heating apparatus gathers, comprise: the temperature of when the liquid boiling in this container, measuring the heater of this equipment, if more described temperature and reference temperature and described temperature reduce to be applied to the power of described heater than the big predetermined threshold of this reference temperature.

36., comprise the power that is reduced to this heater according to claim 1,2 or 3 described methods as claim 34 or 35 described methods.

37., comprise an independently audible or observable indication that needs scale removal to the user as claim 34,35 or 36 described methods.

38. the liquid heating apparatus that a use has an electronic-controlled installation is heated to a liquid method of predetermined temperature, comprise: apply the heater of first power to described equipment, determine the time of the temperature of this liquid near preferred temperature, and after this with power reduction to one second lower-wattage that applied up to reaching described desired temperatures.

39. liquid heating apparatus that is configured to implement as claim 21 to 28 or 32 to 38 arbitrary described methods.

40. electronic controller that is used for a liquid heating apparatus as claimed in claim 39.

41. be specially configured to implementing computer software as claim 21 to 28 or 32 to 38 arbitrary described methods.