GB2321178A

GB2321178A - Removable heating controller for deep fryer

Info

Publication number: GB2321178A
Application number: GB9800525A
Authority: GB
Inventors: Rolan Eden
Original assignee: Kenwood Marks Ltd
Current assignee: Kenwood Marks Ltd
Priority date: 1997-01-18
Filing date: 1998-01-12
Publication date: 1998-07-22
Anticipated expiration: 2018-01-12
Also published as: GB9701039D0; GB9800525D0; GB2321178B

Abstract

An arrangement is described for ensuring that probes for thermostatic control and thermal fusing of an electrical appliance, such as a deep fryer, establish intimate electrical contact with a container forming part of the appliance. The probes 6,7 are elongate, and can slide relative to the container so as to pass beneath a bracket 10 secured to the container 1 and dimensioned so as to provide an interference fit between the probes 6, 7 and the container 1. The invention finds particular application to appliances from which the container is removeable, together with a heating element 2, when the probes 6,7, together with electrical connectors 8,9 for the heating element, can be carried by a removeable connector module 5 and the electrical and thermal contacts can be made and broken by the same movement.

Description

ELECTRICALLY-HEATED APPLIANCE This invention relates to electrically-heated appliances, particularly of the type using a sheathed heating element in which the temperature of the appliance is thermostatically controlled. One specific example of such an appliance is an electric deep fryer primarily for domestic use.

Conventional deep fryers usually comprise a metal container or tank for containing the fat or oil in which food is fried, the tank being heated by an electrical heating element and being permanently-fixed within an outer casing closable by a lid. A wire basket for holding food to be fried is removably placed in the tank. Since the casing contains electrical components, the combined casing and tank cannot be safely immersed in water and is therefore difficult to clean. In order to solve this problem, deep fryers have been proposed in which the tank is removable from the casing and is capable of being immersed in water to facilitate its cleaning. In order to achieve this, all of the electrical components, except possibly the heating element, are fixedly mounted in the outer casing. In a preferred arrangement, the heating element is mounted in thermal contact with the underside of the tank.

Deep fryers are required to operate with the tank and its contents at a temperature set by the user, and the electrical components therefore generally include a thermostat to switch the electrical power on or off as appropriate in order to maintain the desired temperature. A thermal fuse.

can also be provided and is arranged to blow if an excessive temperature is detected. In order that the operating temperature may be accurately monitored, excellent thermal contact of the thermostat needs to be established and maintained with the external surface of the removable tank when it is located in the outer casing.

To obtain good quality food products cooked by the fryer, rapid initial heating of the oil as well as a fast thermal recovery time after the uncooked food is placed in the heated oil are necessary, which dictates the use of a reasonably high-powered heating element. The control of such elements dictates that the thermostat be mounted in good thermal contact with the tank. Even if this is arranged, however, conventional thermostat/thermal fuse mountings do not ensure that adequate protection will be achieved in all circumstances.

It is an object of the present invention to provide a deep fryer or other electrically-heated appliance in which separate or combined probes for the thermostat and the thermal fuse are removably mounted in good thermal contact with the appliance and can be engaged therewith by means of a sliding movement.

According to one aspect of the invention, there is provided an electrically-heated appliance having a container provided with a heating element, elongate probe means for thermostat and thermal fuse devices, for sensing and controlling the operating temperature of the container, and a member for urging said probe means into intimate thermal contact with the container; said probe means being removable from the appliance by lengthwise sliding movement relative thereto and said urging means being arranged to co-operate with the probe means to reestablish said intimate thermal contact when said probe means is replaced in the appliance by length-wise sliding movement in the opposite direction to that used during removal.

Preferably, the probe means comprises separate elongate probe members for the thermal fusing and thermostat functions, although a combined probe can be used if preferred.

Preferably also, the urging member comprises a bracket member secured to the base of the container, the probe or probes suffering an interference fit between the bridge and the base of the container.

According to another aspect of the invention, there is provided a deep fryer comprising an outer casing closable by a lid, a container for containing oil located in said outer casing, a heating element in thermal contact with the container for heating the oil contained therein, elongate probe means, for thermostat and thermal fuse devices, removably mounted in thermal contact with said container for sensing and controlling the temperature thereof, and a bracket member urging said probe means against said container and from which said probes may be withdrawn by length-wise sliding movement thereof relative to the container.

In a preferred arrangement, the container is removable from the outer casing. In this arrangement, the heating element may be permanently mounted on the container, preferably on the underside thereof, and be provided with coeperable electrical connection means for providing power to the heating element when the container is located in the outer casing. The probe or probes for the thermostat device and for the thermal fuse are slid length-wise into the outer casing in such a position as to establish thermal contact with the container when the container is operatively located in the outer casing.

The invention will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 shows a perspective view of the relevant components of a deep fryer in accordance with an embodiment of the invention; and Figure 2 shows an alternative perspective view of the deep fryer.

Referring now to the drawings, a deep fryer comprises a container or tank 1 which is removably located within an outer casing (not shown) and is intended to contain oil for cooking foods. A removable wire basket (not shown) for holding the food is placed in the tank.

A tubular heating element 2, having an appropriate power rating (such as 1kW to 3kW), is mounted in known manner to the underside of the tank, such that the heating element is in good thermal contact with the tank, and can thus heat the oil in the tank when the element is energised. When the removable tank 1 is operatively located in the outer casing, electrical end connections 3, 4 respectively of the heating element 2 co-operate with electrical connections contained in a removeable connector module 5 which is pushed into a recess in the outer casing in order to supply power to the heating element.

The thermostat and thermal fuse, the arrangements for which constitute the principal subject matter of this patent application, comprise (in this example) respective elongate probes 6 and 7 carried by the module 5 and protruding therefrom as shown in the drawings.

It will be seen from the drawings (and in particular from Figure 2) that the electrical connections 3, 4 provided at the ends of the heating element 2 are in the nature of jacks or probes which enter into respective suitably shaped and dimensioned apertures 8 and 9 in the connector module 5 establishing, upon such entry, electrical connection to the power circuitry of the appliance.

The entry of the connections 3, 4 into their respective apertures 8 and 9 involves, as will be readily appreciated, linear sliding movement in the direction of the axes of the apertures 8, 9.

It will be seen that the elongate probes 6 and 7 for the thermostat and the thermal fuse have axes which extend parallel to those of the connections 3, 4 and the apertures 8, 9. This is an important feature of the operational arrangement permitted by this embodiment of the invention, as it enables the probes 6 and 7 to be moved into operational engagement with the underside of the container 1 (to establish intimate thermal contact therewith) by means of the same sliding movement that is used to cause the connectors 3 and 4 to enter the apertures 8 and 9 respectively. This sliding movement is effected length-wise of the probes.

The probes are positioned so that, when the container 1 is placed into its operative position within its outer casing and the connector 5 is slid into place relative thereto to cause the connectors 3, 4 to enter the apertures 8, 9, the probes 6, 7 slide along the underside of the container 1. During this movement, the probes 6, 7 move under a member comprising a bracket 10 which is dimensioned and constructed so as to urge the probes 6, 7 into intimate engagement with the underside of the container 1 so as to ensure excellent thermal contact therewith. In this particular embodiment of the invention it is convenient, though not essential, for such thermal contact to be established near to the central loop 11 of the meandering run of the heating element 2.

The bracket 10 is shown in its position as affixed to the underside of container 1 in Figure 1 (from which the element 2 has been removed for clarity) and separate from the underside of container 1 in figure 2. It may be merely of squared off U-shape and configured to form an interference fit of the probes 6, 7 between the underside of the container 1 and the bracket itself. Alternatively or in addition, however, the major surface of the bracket 11 may be indented, as shown at 12, 13 in Figure 2, or otherwise shaped or configured to provide a resilient urging force to press the probes 6, 7 tightly against the underside of the container 1.

The arrangement described is such as to ensure excellent thermal contact of the probes 6, 7 with the underside of the container 1 by means of the same sliding movement of the connector 5 as is required to establish electrical connection to the heating element 2 and thus provides an efficient and cost-effective solution to the problem of making removable contact between the probes and the container.

The temperature of the oil in the tank 1 is settable by a user-operable control on the outer casing which sets the operating response of the thermostat.

The thermostat is connected in the power supply line to the heating element 2, so that its activation will disconnect the power to the element.

Additionally, the thermal fuse (including probe 7) is arranged to blow in the event of failure of the thermostat.

During normal operation of the fryer, the user-controllable thermostat is set to the temperature required and power is supplied to the heating element 2 to heat up the oil in the tank 1 as quickly as possible. The probe 6 and its associated thermostat directly monitors the temperature of the tank and prevents its temperature from exceeding the chosen operating level.

If the thermal fuse senses, via probe 7, that excessive heating is occurring then the fuse will blow, cutting off the power to prevent potentially hazardous circumstances arising.

It will be appreciated that the use of a separate probe 7 for the thermal fuse, mounted in close thermal contact with the tank 1 and, moreover, removeably so mounted by means of an arrangement which also accommodates the probe 6 for the thermostat provides an efficient and economic arrangement that enables proper control to be exercised over the operation of the appliance. The fact that the close thermal contact between the probes and the tank can be established by the same operation that makes the necessary electrical connections to the heating element 2 is additionally advantageous.

Claims

1. An electrically-heated appliance having a container provided with a heating element, elongate probe means for thermostat and thermal fuse devices, for sensing and controlling the operating temperature of the container, and a member for urging said probe means into intimate thermal contact with the container; said probe means being removeable from the appliance by length-wise sliding movement relative thereto and said urging means being arranged to co-operate with the probe means to re-establish said intimate thermal contact when said probe means is replaced in the appliance by length-wise sliding movement in the opposite direction to that used during removal.

2. An appliance according to Claim 1 wherein the probe means comprises separate elongate probe members for the thermal fusing and thermostat functions.

3. An appliance according to Claim 1 wherein the probe means comprises a combined probe member for both thermal fusing and thermostat functions.

4. An appliance according to any preceding claim wherein the urging member comprises a bracket member secured to the base of the container and providing an interference fit for the probe means between the bracket and the base of the container.

5. An appliance according to any preceding claim wherein the urging member is arranged to provide resilient force urging said probe means against said container.

6. An appliance according to any preceding claim including a remove able connector means carrying said probe means and electrical connections for said heating element.

7. An appliance according to Claim 6 wherein said length-wise movement is effected between said connector and the container and said electrical connections are established during the same movement.

8. An appliance according to any preceding claim wherein said container is removeable from the appliance.

9. An appliance according to any preceding claim wherein the heating element is permanently secured to said container.

10. An appliance according to any preceding claim wherein said heating element is disposed in meandering form on the base of the container and the probe means, when engaged by said urging member, is disposed close to at least one portion of said element.

11. An appliance substantially as described with reference to the accompanying drawings.

12. A deep fryer comprising an outer casing closable by a lid, a container for containing oil located in said outer casing, a heating element in thermal contact with the container for heating the oil contained therein, elongate probe means, for thermostat and thermal fuse devices, removably mounted in thermal contact with said container for sensing and controlling the temperature thereof, and a bracket member urging said probe means against said container and from which said probes may be withdrawn by length-wise sliding movement thereof relative to the container.