[0001] The invention relates to a heating unit for a cooking hob comprising at least two
spaced-apart heat sources, each of which is formed by at least one infra-red heating
lamp for heating substantially circular areas of the hob surface.
[0002] Such a heating unit for a cooking hob is known from French Patent No. 2.138.464.
This hob comprises a glass ceramic cooking top and two heat sources. One source is
formed by two concentric quartz glass tubes, the other by three concentric quartz
glass tubes.
[0003] The object of the invention is to enable the user to make more effective use of the
cooking hob, i.e. to have the possibility of using different types of pans and effect
heating of each pan in an energy-saving manner.
[0004] According to the invention the heating unit is characterized in that an intermediate
heat source is disposed between the two spaced-apart heat sources, which intermediate
heat source is formed by at least one infra-red heating lamp of a rectilinear type.
On such a cooking hob not only the conventional circular pans of different diameter
can be used, but also rectangular or oblong pans, either on an oblong area heated
by the straight intermediate infra-red heating lamp or on a combination of one or
two circular areas and the oblong area.
[0005] In one embodiment of the heating unit the one or more rectilinear lamps are arranged
substantially perpendicular to a line interconnecting the centres of the two circular
heating areas.
[0006] By way of example, a particular embodirent of the invention will now be described
with reference to the accompanying drawing, the single figure of which shows a perspective
view, partly in sections of a cooking hob having a heating unit according to the invention.
[0007] In the figure, the reference numeral 1 indicates a glass ceramic cooking top rigid
with a perimetral metal frame 2 which abuts on to the wooden worktop 3 of a kitchen
unit 4. Below the cooking top 1 there is a heating unit comprising two spaced-apart
heat sources 5, 6 which in this example are identical and are each constituted by
three infrared lamps 7 of open circular ring form, disposed so as to be substantially
concentric with one another for heating substantially circular areas of the top, and
a third heat source 8 between the two preceding sources.
[0008] The third heat source is constituted by a single infrared lamp 9 of a rectilinear
type which is substantially perpendicular to the straight line passing through the
centres of the two groups of circular lamps 7. It is also possible to have more than
one intermediate infra-red heating lamp of the rectilinear type.
[0009] The various lamps have moulded ceramic end-caps 10 from which insulated conductors
(not shown) emerge for feeding the electrical energy.
[0010] Each of the heat sources 5, 6 is controlled by its own multi- position electrical
rotary switch which enables the relevant lamps to be fed in various series and/or
parallel combinations or individually. Alternatively, the power of each of the heat
sources 5, 6 can be regulated by devices for modifying the sinusoidal wave of the
supply voltage, commonly known as choppers or light dimmers.
[0011] The intermediate heat source 8 can be controlled in a manner analogous to that indicated,
especially where the lamps are more than one in number, or by means of a simple mechanically
retained pushbutton, i.e. such that on being pressed it connects the lamp, and on
being again pressed it disconnects it.
[0012] If a cooking utensil with an oblong base is to be heated, such as a fish pan, indicated
by dashed and dotted lines and by A in the figure, the three heat sources 5, 6 and
8 are fed, and if required their heating power is regulated by one or more of the
aforesaid regulator members. Alternatively, use can be made of only the intermediate
heat source if only a small oblong cooking utensil is used.
[0013] As described, a circular area of the cooking top can be heated by circular infra-red
heating lamps. It is also possible to use a heating source of three or four infra-red
heating lamps of the rectilinear type which are disposed parallel to each other. When
the outer lamps are shorter than the inner lamp or lamps a substantially circular
heating area will be obtained.
1. A heating unit for a cooking hob comprising at least two spaced-apart sources,
each of which is formed by at least one infra- red heating lamp for heating substantially
circular areas of the hob surface, characterized in that an intermediate heat source
is disposed between the two spaced-apart heat sources, which intermediate heat source
is formed by at least one infra-red heating lamp of a rectilinear type.
2. A heating unit as claimed in Claim 1, characterized in that the one or more rectilinear
lamps are arranged substantially perpendicular to a line interconnecting the centres
of the two circular heating areas.
3. A cooking hob having a glass ceramic cooking top, characterized in that at least
one heating unit according to any previous claim is disposed beneath the top.
