FR2779336A1 - ELECTRIC COOKING APPARATUS, ESPECIALLY A FRYER, COMPRISING A SECURITY DEVICE - Google Patents

Abstract

The invention concerns an electrical cooking appliance comprising, in a housing (1), a metal bowl (2) provided externally on its base with a heating element (5). The invention is characterised in that the appliance comprises a bimetal switch (11) in direct thermal contact with the heating element (5), and mobile in response to an excess of heat produced by the heating element (5) and corresponding to a substantially empty bowl (2), to take up an active position wherein it controls the heating element (5) power supply circuit opening. The invention is applicable to electric deep fryers.

Description

The present invention relates to electric cooking appliances,

  in particular but not exclusively to electric fryers intended for cooking, in a

  oil bath in particular, foods such as fri-

  fish or meat, and comprising, in a housing, a metal tank and a heating element

  externally attached to the bottom of the tank.

  When using such a cooking appliance, for example a fryer, there is always the risk that the user forgets to fill the tank with oil and

  triggers the frying operation, leading quickly

  damage to the tank, such as cracking

  tion of the coating, for example an enamel, which is generally

  also used to facilitate cleaning of the tank and

  which covers this inside and out

  even an inflammation of the fryer due to

  the presence of a film of residual oil on the walls

dull of the tank.

  The object of the invention is in particular to alleviate these in-

  convenient and simple and inexpensive

  an electric cooking appliance of the exposed type

  above, which offers great functional safety-

  in respect of any risk linked to the absence of oil

  or too little oil in the tank.

  According to the invention, the apparatus further comprises a bimetallic strip arranged in direct thermal contact with the element.

  and movable in response to excess heat produced by the heating element during operation-

  the appliance and corresponding to a sensitive tank

  completely empty, to come and occupy an active position in

  which it controls the opening of the supply circuit

  the heating element.

  By excess heat is meant heating of the heating element occurring at a temperature

  of this element which exceeds a predefined maximum temperature

  finished representative of an empty or insufficient oil tank

filled with oil.

  Thus, the bimetallic strip being placed in perfect condition

  tion of heat exchange with the heating element, it is understood that any excessive heating of this element

  causes the bimetallic strip to move in order to cut quickly

  heating when the tank is empty of oil or

  is insufficiently filled with oil, thus providing

  optimal safety for the user. In addition, the bimetallic strip constitutes a temperature-sensitive organ which

  is inherently simple, inexpensive and reliable.

  The characteristics and advantages of the invention

  will emerge from the description which follows,

  by way of nonlimiting example, with reference to the accompanying drawings in which: - Figure 1 is a partial schematic view in

  vertical section of a cooking appliance, such as a fri-

  teuse, in normal operation; and - Figure 2 is a view similar to Figure 1,

for an empty oil tank.

  In the embodiment illustrated in FIG. 1, the electric fryer comprises an external housing 1

  shown here schematically in dashed lines, which

  limits a closed enclosure thanks to a cover (not

  presented), and inside which is placed a metal tank 2, for example of rectangular shape, provided externally on its bottom 4 with an electric heating element 5, suitable for heating the tank and constituted for example by an armored resistance which is attached to the external face 4a of the bottom 4 of the tank by any means of

  suitable fixing, for example by welding.

  In this example, the tank 2 provided with the heating resistor 5 is mounted fixed, in a manner known in

itself, in the housing 1.

  Of course, the tank 2 provided with the heating resistor 5 can also be removably mounted in the

  box 1, without departing from the scope of the invention.

  The tank 2, present in the housing 1, is intended

  to contain an oil bath 7 for cooking by immersion

  sion of food, such as for example fries 8,

  kept in a frying basket 9, as illustrated in the

figure 1.

  Advantageously, the tank 2 is produced by embou-

  weaving a sheet metal plate, for example steel, and is then covered internally and externally with a heat resistant coating, for example enamel, which makes it easier to clean the tank

  and to avoid the adhesion of food on the internal surface

tank.

  The armored heating resistor 5 has for example a triangular cross section, as visible in FIGS. 1 and 2, and is advantageously shaped as

  a coil to promote its thermal contact

  that over the entire length and width of the bottom 4

  of the rectangular tank 2 in this example.

  According to the invention, the electric fryer further comprises a bimetallic strip 11 disposed in direct thermal contact

  with heating resistor 5 and displaceable in re-

  response to excessive heating of the resistor 5

  producing during operation of the fryer and cor-

  responding to a tank 2 substantially empty of oil (Figure 2), so as to come occupy an active position, as illustrated in Figure 2, in which it controls the opening of the electrical supply circuit of the

heating resistor 5.

  In the embodiment shown in the figure

  gure 1, the bimetallic strip 11 has an approximate general shape

  matively rectangular elongated extending flat in

  below the heating resistor 5, in a di-

  section substantially parallel to the width of the tank 2.

  In this example, the bimetallic strip 11 comprises a first ex-

  free end 13, slightly curved upwards, which is in point contact, denoted P in FIG. 1, against a section of the heating resistor 5, and a second end 15 which is pivotally mounted on the body 17 of a switch switch 19 arranged in the electrical supply circuit of the heating resistor 5.

  In this embodiment, the safety switch

  curity 19 is of the normally open type and comprises a movable control button 20, associated with a spring

  reminder 22, the actuation of which is subject to pivot

  bimetal 11 and whose depression closes the con-

  tacts; this switch 19 has electrical connections

  triques 23, 24 intended to be connected to the feed circuit

  electrical indication of the heating resistor 5.

  This direct mounting of the bimetallic strip 11 on the body of the safety switch 19 advantageously allows

  to obtain a safety device which is specific

  compact and space-saving within the fryer. In addition, the bimetallic strip 11 also functions advantageously as a control member for the opening and the

closing the switch 19.

  In normal operation of the fryer, i.e.

  tell when the tank 2 is sufficiently filled with oil,

  and after diving into the oil bath of the basket of fri-

  ture 9 containing the food to be fried, as illustrated in FIG. 1, the bimetallic strip 11 occupies a rest position in which it bears by its free end 13 on the heating resistor 5 and holds down the button 20 of the switch 19 , against the return spring 22, which switch 19 is in the closed state

  and authorizes the passage of current in the supply circuit

  electrical indication of the heating resistor 5. Since the temperature of the resistor 5 remains below a maximum admissible temperature, the bimetallic strip 11 does not

  does not heat up enough to be able to deform.

  If now tank 2 is empty or insufficiently

  filled with oil, as illustrated in figure 2, the temperature

  resistance 5 increases rapidly to exceed

  ser the maximum allowable temperature, then causing by heat exchange an appropriate deformation of the free end 13 of the bimetallic strip 11; as a result of this deformation, the bimetallic strip 11 swings counterclockwise to come to occupy its active position (FIG. 2) in

  which it releases the button 20 of the switch 19, the-

  which button 20 goes back under the action of its return spring 22 and causes the opening of the switch 19,

  thus enabling rapid switching off by heating cycle

  resistance fage 5. As shown in figure 2,

  the free end 13 of the bimetallic strip 11 remains in abutment

  tuel, noted Q in this figure 2, when the bimetallic strip occupies

its active position.

  It will be indicated that in the case of a removable tank carrying the heating resistor 5, the positioning of the tank in the housing 1 causes, by mechanical support of the resistor 5 on the free end 13 of the bimetallic strip 11, a tilting from the bimetallic strip 11 to its rest position, as illustrated in FIG. 1, in which the bimetallic strip allows the electrical supply circuit to be closed

of the heating resistor 5.

Claims (5)

  1. An electric cooking appliance comprising, in a housing (1), a metal tank (2) intended for cooking food, and a heating element (5) brought outwardly on the bottom (4) of the tank (2), characterized in that it further comprises a bimetallic strip (1) disposed in direct thermal contact with the heating element (5), and displaceable in response to an excess of heat produced by the heating element ( 5) during operation of the device and corresponding to a substantially empty tank (2), to come occupy an active position in which it controls the opening of the circuit   power supply to the heating element (5).   2. Apparatus according to claim 1, comprising   a switch (19) arranged in the supply circuit   the electric element of the heating element (5) and having a body (17) provided with a movable control button (20), characterized in that the bimetallic strip (11) is mounted movably by one (15) of its ends on the body (17) of the switch (19) and occupies a rest position for   which the device is in normal operation corresponds to   laying in a sufficiently filled tank (2) and in   which, on the one hand, its free end (13) is app-   then against the heating element (5), and on the other hand,   it controls the button (20) of the switch (19) of ma-   to close the electrical supply circuit of the heating element (5), said bimetallic strip (11) passing from its rest position to its active position in response to the excess heat produced by the heating element ( 5) and controlling, in its active position, the button (20) of   the switch (19) so as to open the supply circuit   electrical indication of the heating element (5).   3. Apparatus according to claim 2, characterized in that the bimetallic strip (11), by its end   (15) opposite its free end (13), is pivotally mounted   both on the body (17) of the switch (19).   4. Apparatus according to claim 2 or 3, characterized in that the free end (13) of the bimetallic strip (11) is shaped so as to remain in abutment against the heating element (5) when the bimetallic strip occupies its active position , the bimetallic strip (11) passing from its rest position to its active position as a result of a deformation which the free end (13) of the bimetallic strip (11) undergoes under the effect of the excess heat produced by the element of heating (5).   5. Apparatus according to any one of the claims previous statements,   characterized in that it is constituted by a fryer.