GB2229939A - Cooking apparatus - Google Patents

Abstract

Cooking apparatus, especially for pressure cooking. A sealable enclosure for food items to be cooked comprises a tray removable from the apparatus and having a sealable lid (30). Means (60) are provided for introducing steam into its enclosure to cause cooking of food items therein. The tray is preferably slidable into and out of the apparatus. <IMAGE>

Description

Title: Cooking Apparatus DESCRIPTION This invention concerns cooking apparatus and, in particular, pressure cooking apparatus.

There is a need for pressure cooking apparatus suitable for use in catering on a medium scale, such as in nursing homes and small hotels.

An object of this invention is to provide cooking apparatus that may be used for pressure cooking.

According to the present invention there is provided cooking apparatus comprising a sealable enclosure for food items to be cooked and means for introducing steam into the enclosure to cause cooking of the food items, the said enclosure comprising a tray removable from the apparatus and having a sealable lid.

The tray is preferably slidable into and out of the apparatus. The tray may, for example, be slidable along a fixed tray guide but is preferably carried by a slidable tray guide which receives the tray.

When a slidable tray guide in used, this preferably has handles to facilitate movement thereof.

The apparatus of the invention is preferably stackable with other such apparatus.

The enclosure of the apparatus of the invention preferably further comprises a lid sealable on the tray, preferably by means of a gasket therebetween.

The lid and tray may be movable together mechanically.

Preferably the lid is movable downwards onto the tray.

It may be useful to have the lid arranged to be moved by a motor such as via a chain drive for rotating screw rods acting on to the lid preferably at or near corners thereof and even intermediate points.

The apparatus of the invention preferably also includes temperature sensing means which may be coupled to steam introduction means, whereby steam is automatically introduced when the temperature in the enclosure falls to a predetermined level. Steam for the apparatus of the invention may be produced in any desired way. The apparatus of the invention may include its own steam generation system or a separate steam generator may be used.

The apparatus of the invention may be used for low pressure and high pressure cooking. Preferably the apparatus will be provided with sensors for detecting whether or not the tray inserted therein is for high or low pressure cooking. Trays for high pressure cooking may be provided with a shaped part to activate a sensor which indicates a high pressure tray, otherwise another sensor is activated indicating a lower pressure tray.

The signal from whichever sensor is activated may then be passed to a safety valve system which includes both low and high pressure safety valves. A valve, typically a solenoid valve may be provided to close off the low pressure safety valve if a high pressure cooking tray is installed in the apparatus of the invention. Otherwise the low pressure safety valve remains on line from an outlet of the enclosure.

The apparatus of the invention preferably has a front closure, correct positioning of which may be required before steam introduction. Preferably the apparatus of the invention has a switch or sensor to detect proper closing of the front closure whereby steam introduction is permitted. The same may apply to the lid of the enclosure again as a safety check.

The invention will now be further described by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a perspective view of an outercasing for a cooking apparatus; Figure 2 is a plan view of a tray and tray guide for the apparatus of Figure 1; Figure 3 is a perspective view of a lid for the tray of Figure 2; Figure 4 is a section on line AA of Figure 3; Figure 5 shows a lid raising and lowering system; Figure 6 is a part section through the apparatus of Figure 1 showing a temperature sensing arrangement; Figure 7 is a front view of one end of a front closure for the apparatus of Figure 1; Figure 8 is a side view showing further detail of the front closure of Figure 7; Figures 9 and 10 show trap switch detail for detecting tray presence; and Figure 11 is a schematic diagram of a safety valve system for the apparatus of Figure 1.

Referring to the accompanying drawings, a cooking apparatus 10 comprises a generally box-like enclosure 12 having a front entry 14. The front entry 14 slidably receives a tray guide 16 (Figure 2) which is three sided having an internal tray supporting lip 18 and a vertical edge 20 which fits in side location of the enclosure 12. The guide 16 has grasping handles 22. The guide carries a tray 24 on its lip 18. The tray may be for high or low pressure cooking and, if high pressure, will be notched at 26 accordingly to match with either of notches 28A of the tray guide. A low pressure tray has no notch but will match with notch 28B. Whichever of notches 25A or B is matched will make a correspondingly positioned trip switch (see Figures 9 and 10) to detect low or high pressure cooking. This concerns a safety valve system to be described later.

A sealed enclosure is formed between the tray 24 and a lid 30 (Figures 3, 4 and 5). The lid 30 has a lower part 32 that sits in the tray 24 and a shelf 36 around the lower part 32 and under which is a compressible gasket 38 for between the tray rim and the shelf 36. The lid has an upper part 40 to which is attached means for moving the lid up and down. That means comprises a series of screw threaded rods 42 three on each side of the lid attached at one end to sprocket wheels 44 and at the other end contacting bearing plates 46 on the shelf 36. The wheels 44 are connected by a chain 46 which is driven by a further sprocket wheel attached to the spindle of an electric motor (not shown). The rods 42 are screw threadedly through a support frame 50 so that the rods move up or down to release or seal the lid.

The support frame 50 also includes studs 52 at each corner for correct location of the lid 30 by cooperation with corresponding holes 54 in the top of the lid. The studs are spring-loaded.

Steam introduction to the enclosure formed by the tray and lid is via a pipeline 60 through the lid. The lid also includes an outlet 62 to a safety valve system (see later).

Turning now to Figure 6 of the accompanying drawings, at the rear of the apparatus is a temperature sensor 70 mounted in a bearing 72 and urged against the tray 24 by means of a spring 74. The temperature sensor 70 is electrically connected to a control system of a steam generator so that steam can be introduced to the tray when the temperature thereof falls to a predetermined level.

The cooking apparatus enclosure 12 has a front closure 80 (see Figures 7 and 8) which is pivotably mounted on a pivot bolt 82 across the lower front part of the enclosure 12. The closure 80 has projecting from one side thereof a stud 83 that is intended to locate in a gap 84 in the front edge of the enclosure 12 and to depress a.plunger 86 that in turn activates a microswitch 88. The microswitch 88 is electrically connected to the steam generation system whereby steam introduction can be prevented unless the front closure 80 is properly closed. In addition, the lid 36 has a depending locking member 89 that holds the front closure in the closed position when the lid is down.

Referring now to Figures 9 and 10, there is shown a trip switch 90 that is used to detect whether the tray is for high or low pressure cooking (see Figure 2). The switch 90 includes a mounting bracket 92 supporting pivotally a bar 94 from which extends normally a rod 96 carrying a bush 98 whose height is adjustable on the rod by means of a grub screw 100.

The bush is positioned to act against a switching member 102 of a microswitch 104.

The microswitch 104 is electrically connected to a solenoid valve 106 (Figure 11) in outlet pipeline 62.

The valve 106 when open brings low pressure safety valve 108 into the line 62 and when closed leaves only high pressure safety valve 110 in the line 62. Two microswitches 104 are provided and their condition when a tray is inserted into the apparatus determines whether or not the solenoid valve is open or closed.

The cooking apparatus of the invention can be table mounted and may be used to cook food items under steam either under low or under high pressure.

Claims (14)

1. Cooking apparatus comprising a sealable enclosure for food items to be cooked and means for introducing steam into the enclosure to cause cooking of the food items, the said enclosure comprising a tray removable from the apparatus and having sealable lid.

2. Apparatus as claimed in claim 1, wherein the tray is slidable into and out of the apparatus.

3. Apparatus as claimed in claim 2, wherein the tray is slidable along a fixed tray guide.

4. Apparatus as claimed in claim 2 wherein the tray is carried by a slidable tray guide which receives the tray.

5. Apparatus as claimed in claim 4, wherein the tray guide has handles to facilitate movement thereof.

6. Apparatus as claimed in any of claims 1 to 5 that is stackable with other such apparatus.

7. Apparatus as claimed in any of the preceding claims, wherein the lid and tray have a sealing gasket therebetween.

8. Apparatus as claimed in any of the preceding claims, wherein the lid is mechanically urgeable into a sealed position.

9. Apparatus as claimed in any of the preceding claims comprising temperature sensing means coupled to steam introduction means, whereby steam is automatically introduced when the temperature in the enclosure falls to a predetermined level.

10. Apparatus as claimed in any of the preceding claims comprising means for detecting whether the tray inserted therein is for high or low pressure cooking.

11. Apparatus as claimed in claim 1O, wherein said detecting means is coupled to a safety valve system which includes both low and high pressure safety valves and a valve to close off the low pressure safety valve if a high pressure cooking tray is installed in the apparatus.

12. Apparatus as claimed in any of the preceding claims comprising a front closure, correct positioning of which is required before steam introduction.

13. Apparatus as claimed in claim 12 having a switch or sensor to detect proper closing of the front closure whereby steam introduction is permitted.

14. Cooking apparatus substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.