The invention provides a device (11) for switching an electric
heater (12) with at least two heating areas (25, 27, 29), which
can be variably supplied with electric power by at least one power
setter (22) and having control means (19) for the at least one power
setter (22, 23) and with functionally separate switching means (14,
16) for operating the at least one power setter. On operating a
first switching means (14), a heating area (27) associated therewith
can be set by means of a power setter via the control means and
on operating a further switching means (16) a heating area (29)
associated therewith is settable by means of a power setter. Preferably,
precisely one heating area (27, 29) is associated with each switching
means (14, 16). The heating areas can be areally extensive heating
zones or different power levels of a heater.
What is claimed is:
1. A device for switching an electric heater, said electric heater
having at least three spatially extensive and neighboring heating
areas, wherein a basic heating zone of said heater is associated
with at least two additional heating zones, said device comprising:
at least one power setter for variably supplying said heating areas
with electric power;
control means for said at least one power setter; and
functionally separate switching means for the operation of said
at least one power setter via said control means;
wherein precisely one of said heating areas is associated with
one of said switching means via said control means;
wherein the heating area associated with a first one of the switching
means is switched on by means of at least one of said power setters,
during operation of said first switching means; and
wherein the heating area associated with further switching means
is switched on by means of at least one of said power setters, during
operation of said further switching means.
2. The device according to claim 1, wherein on the first operation
of one of said switching means, said control means directly sets
the heating area associated with said switching means.
3. The device according to claim 1, wherein on a subsequent operation
of one of said switching means without any change to the power supply
of the heating areas and/or the operating of one of the switching
means during an interval between the first operation and the subsequent
operation, said control means switches off all of said heating areas.
4. The device according to claim 1, wherein said switching means
and/or heating areas are hierarchically subdivided.
5. The device according to claim 4, wherein said switching means
and/or heating areas are subdivided in levels from low to high.
6. The device according to claim 4, wherein on operating a switching
means of a heating area of a higher level than the presently set
level, said control means sets said level.
7. The device according to claim 6, wherein said control means
set said level and all levels below it.
8. The device according to claim 6, wherein on operating a switching
means of a heating area of a lower level than the instantaneously
set level, said control means reset to said lower level and switch
off levels above it.
9. The device according to claim 1, wherein a hierarchic arrangement
of said heating areas in levels corresponds to the spatial association
of said additional heating zones to said basic heating zone.
10. The device according to claim 9, wherein said levels rise from
low to high with increasing distance from said basic heating zone.
11. The device according to claim 9, wherein said heater has a
basic heating zone located in a circular hotplate of an electric
cooker and said additional heating zones form an enlargement of
the heatable surface area, being adjacent as an extension on one
side and/or substantially surrounding said basic heating zone.
12. The device according to claim 9, wherein a power level supplied
to one of said additional heating zones is adapted to a power supply
of said basic heating zone.
13. The device according to claim 1, wherein with each switching
means are associated indicating or display means, said control means
activating said indicating means of the in each case set heating
14. The device according to claim 1, wherein said switching means
are touch switches with a capacitive basis, said switching means
being fitted under a cover.
15. The device according to claim 1, wherein said control means
have a microprocessor with which is associated a memory for operating
states and/or parameters.
FIELD OF USE AND PRIOR ART
The invention relates to a device for switching an electric heater
having at least two heating areas, which can be variably supplied
with electric power by means of at least one power regulator or
setter, with control means for the at least one power regulator
or setter and with functionally separated switching means for operating
the at least one power regulator or setter by means of the control
means. Preferably such a device is used in electric heating appliances,
particularly for the home.
Devices are known in which there are two switching means for switching
on or off a heater. One of the two switches serves as a so-called
release switch, following the operation of which and within a given
time interval the second switch must be operated. As a result of
the operation of the second switch, the heater is switched on. By
again operating the first switch, the heater can be switched off
again. A similar procedure is proposed for switching on several
heating areas of a heater. One switch is a release switch, whilst
with a second switch it is possible to successively and continuously
switch on the different heating areas.
PROBLEM AND SOLUTION
The problem of the invention is to provide a device permitting
a rapid and simple switching of various heating areas in accordance
with the wishes of a user, which is universally usable, reliable
and simple to manufacture.
This problem is solved by claim 1. If the control means during
the operation of a first switching means set a heating area associated
therewith by means of at least one power setter and on operating
a further switching means can set a heating area associated therewith
by means of at least one power setter, it is possible to directly
set the heating areas without a need for multiple operation. Preferably,
precisely one heating area is associated via the control means with
each switching means. A setting preferably takes place by power
setters, particularly in each case one associated power setter.
In this way it is possible with only a single operation of a switching
means to directly set a desired heating area, which reduces both
effort and possible incorrect operations. Preferably, the control
means sets the heating area on the first operation of a switching
means for said heating area.
According to a further development of the invention, in the case
of a further or second operation of the same switching means, the
control means switch off part of the heating areas, preferably all
the switched on heating areas. Preferably, between the two operations,
there is no intermediate change to the electric power supply to
the heating areas and/or operation of one of the switching means.
If another heating area was set, now the new heating area corresponding
to the operated switching means is set.
The switching means and/or heating areas are preferably hierarchically
subdivided and in particular it is advantageous to have a subdivision
from low to high. Alternatively other subdivisions are possible,
although the aforementioned is preferred.
In one operating procedure, on operating a switching means of a
heating area in a higher step or level than the instantaneously
set step or level, the control means can rise to said step or level.
Levels below it can be switched off, but preferably the control
means also set the levels below it. This means that through an operation
of a specific switching means, its heating area and all the heating
areas below it can be set or switched on.
On operating a switching means of a heating area of a lower level
than the instantaneously set level, the control means can reset
to this lower level. It is also considered advantageous to switch
off levels above it but, in accordance with what was stated hereinbefore,
can also remain set.
In a preferred application of the invention, particularly in the
case of domestic electric heating appliances such as electric cookers,
the heating areas can be spatially or areally extensive heating
zones. In particular, as additional heating zones they are associated
with a basic heating zone of the heater and are preferably adjacent
to the basic heating zone. The basic heating zone can be substantially
surrounded by the additional heating zones, either by each additional
heating zone or several or even all of the latter.
A possible hierarchic arrangement of the heating areas in different
levels can correspond to the spatial association of the additional
heating zones with respect to the basic heating zone. In one possibility
the additional heating zones rise in steps as a function of their
size and preferably an increasing distance from the basic heating
zone is used as a basis for the rise.
In a performance possibility of the invention the heater can have
a basic heating zone arranged in a circular hotplate of an electric
cooker, the additional heating zones forming an enlargement of the
heatable surface, preferably being adjacent on one side as an extension
and/or substantially surrounding the basic heating zone. This is
e.g. possible with an electric cooker having four hotplates, including
a concentrically larger, heatable circular area for particularly
large cooking vessels and laterally facing additional heating zones
for baking devices or the like.
A link between the heating of the heater and the heating areas
can be that a power supplied to at least one of the additional heating
zones is adapted to a power supply to the basic heating zone. Thus,
it is possible in the above case, with a basic heating zone set
to a given cooking power, the additional heating zones can be supplied
with the latter on setting.
As an alternative to additional heating zones, the heating areas
can be different power levels of the heater. The power levels are
in particular arranged in rising manner, preferably from 0 to maximum.
An embodiment of this inventive aspect would e.g. be a heater with
a stepwise adjustable power and a plurality of switching means,
to each of which corresponds a power stage or level. A setting of
the desired power level takes place by operating the particular
switching means and not with a rotary toggle, as e.g. occurs in
known electric cookers.
With each switching means can be associated indicating or display
means, preferably in spatial proximity to the switching means. The
control means can activate the display means of the in each case
set heating area and preferably only the display means of said heating
area. The display means of further, optionally set heating areas
of said heater are preferably not set. The display means are preferably
constituted by an optical display or indicator, e.g. an illuminated
display, preferably with bulbs or in particularly preferred manner
with light emitting diodes.
As switching means are suitable touch switches, preferably having
a capacitive basis. They are preferably installed under a cover,
e.g. a glass ceramic hotplate. Particular preference is given to
contact switches with a spatially extensive, inherently flexible
sensor body, which is shape-variable. Touch switches of this type
are e.g. described in German patent application 197 06 168.0.
The power setters can be constituted by mechanical switches, preferably
electromechanical switches, power relays being e.g. suitable.
The control means can have a microprocessor, which is preferably
connected to a memory for operating states and/or parameters or
contains the same. In this case the switching means supply a signal
initiating a switching process. The microprocessor can take over
further functions. It is also possible to associate with the switching
means further functions, e.g. for a change in the configuration
of the entire device or an electric heating appliance.
These and further features can be gathered from the claims, description
and drawings and the individual features, either singly or in the
form of subcombinations, can be implemented in an embodiment of
the invention and in other fields and can represent advantageous,
protectable constructions for which protection is hereby claimed.
The subdivision of the application into individual sections and
the subtitles in no way limit the general validity of the statements
BRIEF DESCRIPTION OF THE DRAWING
An embodiment of the invention is described hereinafter relative
to the single diagrammatic drawing of a device for switching a heater
with several heating zones by means of a microprocessor connected
to two touch switches.
DETAILED DESCRIPTION OF THE EMBODIMENT
The drawing shows a switching device 11 according to the invention
for switching an electric heating device 12, which can e.g. be a
radiant heater of a glass ceramic hotplate. The switching device
11 has as switching means a touch switch 14 and a further touch
switch 16. With the first touch switch 14 is associated an optical
signal indicator or display 15, whilst a second signal indicator
or display 17 is associated with the second touch switch 16.
The diagrammatically shown heating device 12 has a basic heating
zone 25, a first additional heating zone 27 and a second additional
heating zone 29. In the represented embodiment the additional heating
zones 27, 29 roughly concentrically surround the basic heating zone
25. However, it is also possible to adopt constructions in which
the additional heating zones are laterally linked with a basic heating
zone. Combinations of surrounding and laterally connected additional
heating zones are also possible. The shape of the heating zones
is not restricted to substantially circular constructions.
The first and second touch switches 14 and 16 are connected to
control means in the form of a microprocessor 19, as are the indicators
15 and 17. The microprocessor 19 is also connected to input means
10, which in the represented embodiment set the level of the electric
power supplied to the heating device 12.
The microprocessor 19 is connected to a power regulator or setter
22, which comprises several switching units 23. Each of the two
additional heating zones 27, 29 has its own switching unit 23, with
which it is connected by means of a first additional connection
28 and a second additional connection 30. The basic heating zone
25 is connected by a connection 26 to its own switching unit 23.
The switching units 23 of the power setter 22 can be constructed
in such a way that the same adjustable power level can be supplied
to all the heating zones of the heating device 12. For this purpose
the switching units 23 of the first and second additional heating
zones 27 and 29 are e.g. constructed as simple on/off switches,
whereas the switching unit 23 of the basic heating zone 25 determines
the power level for the complete heating device 12. It can e.g.
be constructed as a timing power control device. It is alternatively
possible to construct all the switching units 23 as such timing
power control devices, so as to be able to in this way individually
set the power level of all the heating zones 25, 27 and 29.
Thus, the drawing shows a heating device 12 with three heating
areas. On removing the basic heating zone 25 and the input means
20, there is a heating device settable by means of the touch switches
14 and 16 and having the two heating zones 27 and 29. The switching
on or off of the heating zones takes place in the above-described
manner. Using separate input means it is possible to determine the
level of the power supply of the in each case set heating zones
27 or 29. In the case of a heating device with e.g. five additional
heating zones there would be five touch switches.
As a function of the heating device 12 the switching units 23 can
be differently constructed, e.g. as electromechanical switches or
power relays. Particularly for induction heaters power electronics
components can be used.
An advantageous functional sequence in an exemplified use in a
hot point of an electric cooker made possible by the invention can
take place in the following way. A certain power level of the basic
heating zone 25 is set by the input means 20. If the size of a cooking
vessel placed on the heating device 12 significantly exceeds the
size of the basic heating zone 25, the additional heating zones
27 and/or 29 are required. If a user operates the first touch switch
14, the first optical signal indicator 15 lights up and the microprocessor
19 actuates the switching unit 23 of the first additional heating
zone 27. By means of the additional connection 28, the latter, like
the basic heating zone 25, is connected to a power supply and have
the same power level. Thus, the heated surface area of the heating
device 12 is considerably increased.
If the once extended heating surface of the heating device 12 is
not large enough for a cooking vessel, by means of the second touch
switch 16 and in the same way using the microprocessor 19 and the
associated switching unit 23 the second additional heating zone
29 can be switched on. Thus, there is a synchronization of all three
heating zones 25, 27 and 29 of the heating device 12. The microprocessor
19 switches on the second optical signal indicator 17 and preferably
switches off again the first optical signal indicator 15.
If, directly and in addition to the basic heating zone 25, the
second touch switch 16 is operated, then the microprocessor 19 sets
the first additional heating zone 27 and second additional heating
zone 29. The second signal indicator 17 lights up. This makes it
clear that by operating in each case one touch switch directly the
associated switching state of the heating device 12 is set, without
it being necessary to approach it in individual operating stages.
If with the two additional heating zones 27 and 29 switched on,
the second touch switch 16 is operated, the microprocessor 19 switches
off both additional heating zones, both signal indicators 15 and
17 go out and only the basic heating zone 25 remains switched on.
However, if from the aforementioned state, the first touch switch
14 is operated, then switching takes place to the state corresponding
to said switch, which means that all the higher additional beating
zones, in this case the additional heating zone 29, are switched
off. The signal indicator 17 goes out and signal indicator 15 lights
up. Renewed operation of the first touch switch 14 also switches
off the first additional heating zone 27.
According to the invention the heating areas can not only be the
above-described heating zones as an extension of a heating device,
but also different power levels, in particular of a single heater.
Much as described hereinbefore, by operating the corresponding switching
means or touch switches a heating or power level can be set in place
of areal heating zones. On conceiving the heating device 12 as a
single heater and the heating zones 25, 27 and 29 e.g. as levels
I, II and III, i.e. rising power levels, the above-described operating
diagram can be directly used, so that no further explanations are