FR2505596A1 - RESIDUAL HEAT DISPLAY DEVICE FOR AN ELECTRIC COOKER - Google Patents

Abstract

A CIRCUIT 1 CONSTITUTES BY A SIGNAL GENERATOR CIRCUIT 2 IS USED, WHICH GENERATES A SIGNAL ASSOCIATED WITH THE TEMPERATURE OF A COOKING STATION, AND A COMPARATOR CIRCUIT 3 CAPABLE OF COMPARING SEVERAL VALUES. THIS COMPARATOR CIRCUIT 3 COMPARES THE TEMPERATURE SIGNAL WITH VARIOUS PREDETERMINED VALUES WHICH CORRESPOND TO CORRESPONDING TEMPERATURE LEVELS AND WHICH CONTROLS THE DISPLAY DEVICE 6 HAS MULTIPLE SEGMENTS AND AT LEAST ONE DIGIT, SO THAT WHEN THE DEVICES ARE CONNECTED AND DISCONNECTED, AT LEAST THREE DIFFERENT TEMPERATURE LEVELS MAY BE REPRESENTED BY DIFFERENT SYMBOLS.

Description

Residual heat display device for a

electric cooker.

  The present invention relates to a display device

  of residual heat for an electrically heated stove

  that, comprising one or more cooking stations provided with heating devices, control and operating devices, comprising one or more display devices with seven segments concerning both the temperature and / or switching status of the cooking stations cooking when the heating devices are connected only the display in two positions of a too high temperature of the cooking stations when the heating devices are switched off, and comprising a circuit for determining the temperature of the

cooking stations.

  Residual heat display devices for electrically heated stoves are known in particular

  for cookers with glass-ceramic hobs.

  This is how the German application DE-OS 25 45 239 describes a

  electronic temperature controller for heating elements

  gloves, such as hotplates, in which is provided

  a keypad to enter the power or temperature levels

  ture desired To display the switching status of the input keypad, a seven-segment display consisting of

  by an array of diodes In the input keyboard mention-

  born, there is also provided a "zero" key by which, after switching off the heating element concerned, the seven-segment display can be coupled to a resistance thermometer by means of a corresponding circuit, the thermometer being in thermal connection with the hob If the temperature

  of the hob protrudes, after switching off the power

  ce, a predetermined value which is for example 450 C, the display with seven segments is then excited so as to produce a warning display Preferably, it is an H

  which should be displayed in this case.

  This device therefore exclusively serves to inform the user

  sator on the fact that the hot plate is always very hot and that a contact would cause burns But it does not allow to know what is actually the level of the

  temperature of the hot plate after the end of the supply

tation in power.

  But like a hot plate of this type which is

  consisting of a mass can be heated to temperatures

  res can exceed 200 WC after cooking or roasting, it is still possible to use the stored heat

in another way.

  It is by taking these circumstances into account that the pre-

  sente invention relates to a residual heat display device for the use of this residual heat In this case should be used to the maximum

  switches already existing in an electric stove.

  In addition, the display of the residual heat must be clearly distinguishable from the display operating when

  the electric stove is in operation.

  According to the invention, this problem is solved by the fact that the circuit provided for determining the temperature of the cooking stations consists of a signal generator circuit.

  and by a comparator circuit capable of performing the comparison

  sound between several values, an electrical signal Associated with the temperature of the cooking stations which can be produced by the signal generator circuit when the heating devices are connected and disconnected, which signal can

  be compared by the comparator circuit to predefined values

  completed corresponding to the temperature levels to be displayed,

  and in that one or more display devices are used

  ge with multiple segments with at least one digit, by means of which at least three different symbols can be represented corresponding to three different temperature levels depending on the temperature of the devices

  heating of the cooking stations which are connected and disconnected

  dear. The circuit which is intended to determine the temperature of the cooking stations is grouped with the device for

  control for heating devices, and a provision

  memory device and a common interface are provided for

  the excitement of multi-segment display devices.

  The memory device contains the predetermined values

  nees intended for the comparator circuit as well as data according to which the control device controls the power sent to the heating devices according to the

  power or temperature level chosen.

  The display of the temperature of the cooking stations, when the heating devices are switched off, corresponds to the display which is associated with the power or temperature level at which the same temperatures can be

  reached when the heating devices are connected.

  Advantageously, the invention provides that for display

  the temperature of the cooking stations when the

  heating elements are switched off, only the transverse segments

  saux of the multi-segment display are used to display the temperature level, the number of cross-sections shown decreasing when

the temperature drops.

  According to an advantageous arrangement, the display devices

  chage operate continuously when the heaters operate in a certain mode, and operate intermittently when the operating state is different. Display devices, when the display devices

  heating are off, can work intermittently

  tent, and between the display of the symbol corresponding to the temperature can be displayed the symbol corresponding to

the state of "cut".

  Finally, the display devices can be switched to different colors depending on the state

  of operation of the heating devices.

  Thanks to these measurements, the display of the temperature

  dual can therefore be set up so that when the heater is switched off, the symbols displayed

  are identical to those of the power level or temperature

  erection chosen when the heating devices are connected. The measures indicated above make it easier to distinguish the display of the residual temperature when the heating devices are switched off, either by using different symbols or by using symbols of

different color.

  The invention will now be described in more detail with

  reference to the attached drawings which represent two examples

  preferred embodiments of residual heat display-

  the according to the invention, as well as the block diagrams associated therewith In the drawings: FIG. 1 represents a preferred embodiment of a residual heat display device using a seven-segment display, FIG. 2 represents another preferred embodiment of a residual heat display using a sixteen segment display, Figure 3 is a block diagram of a circuit for a residual heat display, and Figure 4 is another block diagram a residual heat display circuit, grouped with the control

  power of the heater.

  Usually the power that is sent to a cook-

  electrically controlled by hand for cooking remains connected until the end or shortly before the end of this cooking In modern cookers, and in particular

  those with glass cooking surfaces-

  ceramic, they continue to present in their heated parts a significant thermal capacity, which means that the cooking surface retains a significant amount of residual heat after firing, this amount being generally unused and released into the environment. even for heating tubes which, in particular for those used for radiant heating, store

a large amount of heat.

  Following efforts to save energy, it now seems reasonable to use this heat

  But to do this you need to have information

  precise information on the quantity of heat available, in particular to estimate this quantity of heat, and information on the temperature of the cooking stations, or of the cooking tubes, after cutting the power sent to the respective heating devices. of the

  present invention, the expression "cooking station" includes

  also takes cooking tubes and other devices

  equivalents mounted in an electric stove.

  To display the residual temperature, it is preferable to use an already existing display device which, for an electric stove in operation, displays

  either the set power level or the temperature level

  erasure associated with this power position When a seven-segment display is used, these positions can be for example between 1 and 9 But the digits 1 to 9 can also be used for the display of the residual temperature, the residual temperature of the cooking stations after switching off the heating devices being associated with the individual temperature levels so that they correspond respectively to the individual temperatures which can be reached according to the degrees of

  power when the heaters are connected.

  In Figure 1 is shown a preferred residual heat display, comprising a display device to

  seven segments The seven segment display shown diagrammatically

  in figure la only uses three trans-

  Fig. 1b, c and d show the configurations

  obtained by means of three, two and a transverse segment.

  It is thus possible to display a residual heat

  in four levels In this case, the three temperature levels

  re corresponding to the usual names of "cooking", "reheating" and "keeping warm" are associated with the three temperature levels The fourth level corresponds to "cold" or "unplugged cooking station" and it can be represented for example by a zero or the capital letter

  A represented in figures le or lf.

  In Figure 2 is shown another example of realization

  preferred tion of a residual heat display comprising a display device with sixteen segments FIG. 2 a diagrammatically represents a usual display with sixteen segments With a display of this type, the figures 10 can also be represented very simply to 19, i.e. display more than nine power levels when the heater is connected To achieve this, the right half of the sixteen-segment display is used as a seven-segment display, two vertical line segments that can represent a "1" On

  Figure 2b is shown the number 12 by way of example.

  Thanks to a display device with sixteen segments of this

  type, you can also represent capital letters.

  In the case of a four-level residual heat display as described with reference to Figure 1, the following capital letters may be

  displayed to indicate the temperature levels mentioned-

  born, either: C for "cooking" (figure 2 c) R for "reheating" (figure 2 d) M for "keeping warm" (figure 2 e)

F for "cold" (figure 2 f).

  In the context of the invention, it is also natural-

  It is possible to display the residual heat on more than

  four levels, using other symbols.

  So that the user can distinguish as easily as possible between the display of the power level

  or the temperature of the cooking stations when the

  heaters are plugged in and the heat display

  residual, it is possible to choose a display device

  chage can be switched to two different colors For example, when the heating devices are connected, the color red can be used, and when the devices

  heating are switched off, that is to say when it comes to

  expensive waste heat, you can use the yellow color It is also possible to let the display devices operate in two different types of operation For example and during the operation of the heating devices, the permanent display can be used, and when it comes to displaying the residual heat, it can operate intermittently, i.e.

  In addition, it is possible, while operating

  intermittent display device, alternately display the residual heat and the symbol indicating

  the "cut" This is particularly valid when using

  the same symbols for displaying the temperature or switching levels when the heating devices

  are connected, and for the display of the residual heat.

  FIG. 3 represents a circuit 1 intended to determine the temperature of the cooking stations, in the form of a diagram

  by blocks Circuit 1 is constituted by a general circuit

  signal generator 2 and a comparator circuit 3 capable of

  compare several values.

  The signal generator circuit 2 receives via

  diary of one or more information lines 4 of the informa-

  tion on the thermal state of the cooking stations In the simplest case, a resistance probe thermally coupled to the cooking station is connected to the signal generator circuit 2 This signal generator circuit 2 produces a

  electrical signal associated with the cooking station temperature

  sound, this signal being sent to the comparator circuit 3 via one or more signal lines 5 The comparator circuit 3 compares the signal depending on the temperature of the cooking station with various predetermined values which are associated with the levels of

  selected residual heat, and it controls accordingly

  laying out a display device 6 for display

  various levels of residual heat.

  Circuit 1 according to the invention, which is intended to deter-

  undermining the temperature of the cooking station and which is the simplest consists of a Wheatstone bridge in which a branch is formed for example by a heating conductor used as a temperature probe An electrical signal passing through the diagonal branch of the bridge circuit is sent to the comparator circuit 3 constituted by several Schmitt trigger circuits mounted in parallel and the switching points of which are set to various appropriate values The display device 6 is then constituted, for example, by a display element with seven segments, which is connected at the outputs of the Schmitt trigger circuits via

  a network of diodes so that depending on the temperature

  deletion of the cooking station, three, two or one segment trans-

  versal works If the temperature of the cooking station falls below 450 C for example, the display

  chage 6 is then completely disconnected.

  FIG. 4 represents another circuit 1 presented in the form of a block diagram, this circuit being grouped with the circuit intended for the control of the heating devices 7 of the cooking stations so as to constitute a central unit 8 In this case, circuit 1 is made up of signal generator circuit 2, comparator circuit 3 and

  an interface 9 intended for the excitation of the display device

  In addition, the central unit 8 contains a control device 10 and a memory 11, the control device 10 being connected to an adjustment device 12 which can be operated by hand. By means of the adjustment devices 12, the control device 10 is adjusted to a determined level of power or

  temperature via an input line 13.

  The control device 10 is connected to the memory 11 via first lines of instructions and data 14, the memory 11 containing data usually associated with the power or temperature levels set and concerning the duration of the initial cooking. , the power of the cooking proper, etc. The control device 10 controls the power supply intended for

  heating devices 7 depending on the switching level

  tion set and it is connected to interface 9 for exci-

  tation of the display device 6 via a

first display line 15.

  The signal generator stage 2 receives via

  re from the information lines 4 the data on the state of the temperature of the cooking stations associated with the respective heating devices 7 and it produces an electrical signal corresponding to this temperature, which is sent to the

  comparator circuit 3 via the lines at si-

  gnaux 5 The comparator circuit 3 is connected to the memory 11 via second instruction lines and

  data 16 Comparator circuit 3 compares the associated signal

  linked to the temperature of the cooking station at pre-

  determined which are contained in the memory 11 In addition, the comparator circuit 3 is connected to the interface 9 for the excitation of the display device 6 via a second display line 17 Depending on the number predetermined comparison values and depending on the temperature of the cooking station, the display device 6 is excited by the interface 9 so that the various symbols already described above can be used for displaying the

  various levels of residual heat.

  In the context of the invention, it is also possible to use instead of the central unit 8 a microprocessor with appropriate peripherals, such as a microchip computer

  unique There are systems (eg Texas Instru-

  elements, TMS 1000), which can be connected directly to a screen

  sink used as a control device 12 Others

  entries can be used to receive information about

  the thermal state of the cooking stations To control the sending of power to the heating devices 7, it is necessary to have recourse to an appropriate interface circuit formed for example by relays or thyristors.

  example of fluorescent displays to constitute the arrangement

  display 6, it is possible to carry out direct-

  the initiation by a microprocessor, and when other display elements are used, a usual excitation circuit

may be required.

Claims (7)

  1 residual heat display device for an electrically heated stove, comprising one or more cooking stations provided with heating devices, control and operating devices, comprising one or more display devices with seven segments relating as well the state of temperature and / or switching of the cooking stations when the heating devices are connected that the display in two positions of a temperature too high of the cooking stations when the devices   heating are switched off, and comprising a circuit for determining   mine the temperature of the cooking stations, characterized in that the circuit (1) is constituted by a circuit generating   signals (2) and by a comparator circuit (3) capable of effecting   kill the comparison between several values, an electric signal   plate associated with the temperature of the cooking stations which can be produced by the signal generator circuit (2) when the heating devices (7) are connected and disconnected, which signal can be compared by the comparator circuit (3) to predetermined values corresponding to the temperature levels to be displayed, and in that one or more display devices with multiple segments (6) with at least one digit are used, by means of which at least three different symbols corresponding to three can be represented   different temperature levels depending on the temperature   ture of the heating devices (7) of the cooking stations that are plugged in and unplugged.   2 residual heat display device according to claim 1, characterized in that the circuit (1) intended   to determine the temperature of the cooking stations is grouped   pe with the control device (10) for the devices   heating elements (7), and in that a memory device (11) and a common interface (9) are provided for excitation   multi-segment display devices (6).   3 Residual heat display device according to the   claim 2, characterized in that the metering device   moire (11) contains the predetermined values intended for the comparator circuit (3), as well as data as a function   of which the control device (10) controls the power   this sent to the heating devices (7) depending on the level   of power or temperature chosen.   4 Residual heat display device according to   any one of claims 1 to 3, characterized in that   display of the temperature of the cooking stations,   when the heating devices (7) are switched off, correspond   pond to the display which is associated with the power or temperature level at which the same temperatures can be reached when the heating devices (7) are connected. Residual heat display device according to   any one of claims 1 to 3, characterized in that   only for the display of the temperature of the cooking stations when the heating devices (7) are switched off, only the transverse segments of the segment display device   multiples are used to display the temperature level   rature, the number of transverse segments represented decreases cloudy when the temperature drops.   6 Residual heat display device according to   any one of claims 1 to 5, characterized in that   the display devices (6) operate continuously when the heaters () operate in a certain mode, and operate intermittently when   the operating state is different.   8 Residual heat display device according to   any one of claims 1 to 7, characterized in that   that the display devices (6), when the devices   heating (7) are switched off, operate intermittently   tent, and in that between the display of the symbol corresponding to the temperature can be displayed, the corresponding symbol in the "cut off" state.   9 Residual heat display device according to   any one of claims 1 to 8, characterized in that   that the display devices (6) can be switched to   different colors depending on the operating state-   heating devices (7).