GB2446952A

GB2446952A - Scraper blade for a cooking vessel

Info

Publication number: GB2446952A
Application number: GB0803204A
Authority: GB
Inventors: Gerald Stanley Sibbett; David Alan Norris
Original assignee: DC Norris and Co Engineering Ltd
Current assignee: DC Norris and Co Engineering Ltd
Priority date: 2007-02-22
Filing date: 2008-02-21
Publication date: 2008-08-27
Also published as: GB0803204D0; GB0703501D0

Abstract

A scraper blade 6 for a cooking vessel is moulded from plastics material and has metallic particles distributed within it. In the event that pieces of the blade break off during use as the result of wear, the pieces may be detected using a metal detector associated with the line through which food product is fed from the vessel following cooking. Alternatively, magnets may be used to extract the pieces from the food product provided that ferrous particles are used. A scraper blade assembly which comprises a plastic scraper blade and a holder which comprises notches and a hook-shaped securing pin for holding the plastic scraper blade in place.

Description

IMPROVEMENTS IN SCRAPER BLADES FOR COOKING VESSELS

It is known for a flowable food product intended for subsequent re-heating to be cooked in a kettle including a dished cooking vessel arranged within a steam heated jacket. A rotary agitator is provided for circulating the contents of the vessel and causing them to be brought into contact with the hot inner surface of the vessel. Scraper blades carried by the agitator serve to scrape the inner surface of the vessel to prevent solid or semi-solid food product adhering to it and becoming over-cooked. The blades may be manufactured from plastics, nylon or a nylon-type material. The scraper blades may be mounted in a support which allows a limited amount of movement of the blade towards and away from the surface of the vessel. In this way, compensation for wear of the scraper blades may take place. Our patent specification No GB 2 417 193 relates to a system of this type. A problem which arises is that, as the scraper blades wear, small pieces of the blades may break off and enter the food product being cooked. In the case of plastics blades, the presence of such pieces in the cooked food product is difficult if not impossible to detect.

In accordance with the invention, a plastics scraper blade has metallic particles distributed within it. The food product being fed from the vessel may be scanned by a metal detecting system or systems in the line or at the end of the line. Quantities of food product which have become contaminated may be identified in this way and extracted. Alternatively, provided that the particles are of ferrous metal, pieces which break off the blades may be extracted by magnets from the food product after it is discharged from the vessel. The ferrous particles are conveniently introduced into the blades by moulding them from a composition incorporating granules containing stainless steel filaments.

Embodiments of the invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 is a diagrammatic plan view of a cooking kettle in accordance with

patent specification No GB 2 417 193,

Figure 2 is a plan view of a scraper blade similar to that disclosed in the above-mentioned specification but incorporating modifications, Figure 3 is a section taken on the line C-C in Figure 2, Figure 4 shows to an enlarged scale the detail at D in Figure 3, Figure 5 is a perspective view of support member for incorporation into the scraper blade shown in Figures 2 to 4, Figure 6 is a plan view of a blade holder and blade assembly, for use as an alternative to the blade shown in the above-mentioned Figures, Figure 7 is an end view of the assembly shown in Figure 6, and Figure 8 is a section on the line A-A in Figure 6.

Figure 1 of the drawings shows in plan view elements of a cooking kettle of the type disclosed in patent specification No GB 2417 193, to which reference should be made for a better understanding of the background to the present invention. Briefly, the kettle incorporates a cooking vessel 1 having a hemispherical bowl which, in use, is filled with food product. A reversible electric motor is mounted on a superstructure 2 for driving in rotation the shaft 3 of an agitator or stirrer. The vessel has a jacket throug1i which steam may be passed so as to raise the temperature of the surface of the vessel to substantially 180 degrees centigrade. A pneumatic cylinder is mounted on the frame for tilting the superstructure away from the kettle and so lifting the agitator out of the bowl.

An arcuate bar 4 concentric with the inner surface of the bowl is secured at its mid-point to the lower end of the drive shaft. The bar 4 thereby has two limbs of equal length which extend away from the point of connection of the bar with the drive shaft, each limb of the bar extending through an angle exceeding 90 degrees. The drive shaft and agitator may be arranged to rotate continuously in what may be regarded as a forward direction indicated by arrow A in Figure 1, such rotation taking place about an axis arranged at an angle of approximately 30 degrees relative to the vertical. With this arrangement the agitator tends to cause the food product to follow a rising and falling path within the bowl. The motor may also rotate the agitator in the reverse direction, B. Plastics scraper blades 6 fitted to the bar 4 are provided to scrape over the surface of the bowl during rotation of the agitator in the forward direction and prevent food product from adhering to the surface and becoming overheated. Although spaced from one another, the blades cooperate to scrape the entire area of the hemispherical bowl surface covered in food product during each revolution of the agitator in the forward direction.

A single scraper blade 6, similar to that disclosed in the above-mentioned patent specification, but incorporating certain modifications, is shown in Figure 2. The blade is carried by a stirrup welded to the bar 4 and is of a dished or shovel-type shape for guiding scraped-off food product away from the bowl wall. The blade is moulded from plastics, nylon or nylon-type material and is defmed by a bottom wall 32 terminating at its free edge in a scraper tip 34 and by side and end walls, 36 and 38, respectively. The tip 34 extends beyond the side walls 36 and is curved in plan to conform to the curvature of the bowl.

The tip has a chamfer 50 so as to present a sharp edge. Projecting from the side walls are integral, aligned trunnions 40 for reception in openings in the stirrup. Cooperation of the trunnions with the openings allows the scraper blade to pivot between extreme positions, as more particularly described in the above-mentioned specificatioh.

The blade, and in particular the trunnions, are reinforced by a stainless steel support section in the form of a bar 51 moulded into a thickened region 52 between the bottom and end walls of the blade. Welded to the ends of the bar are rectangular blocks 53 which serve to prevent rotation of the blade relative to the bar 51. In the event that portions of the blocks protrude through the material of the blade after moulding, excess material may be removed by machining.

When the agitator is rotated in the forward direction A, as depicted in Figure 1, the pressure of food product against the inner side of the bottom wall of the scraper blade biases the blade so that the tip bears against the inner surface of the bowl. Food product scraped from the surface of the bowl is swirled away from the surface towards the centre of the bowl by the side and end walls of the blade. During rotation in the opposite direction, B, the shape of the blade leads to a tendency for it to lift away from the surface.

Figures 6 to 8 depict an alternative to the blade shown in Figures 2 to 5, in the form of a blade and blade-holder assembly. A stainless steel blade holder 10 is of trapezoidal shape. The first end of the holder, constituted by the shorter of its two parallel edges, is formed with a tubular end piece 12 for receiving a support pin 14 intended to be journalled in a rotary support (not shown).

Adjacent the second, opposite end of the holder, tabs 16 projecting from the sides of the holder are turned over so as to enable a scraper blade 18 to be slotted into place between them. The scraper blade is injection moulded from plastics, nylon or nylon-type material, and avoids metal-to-metal contact taking place between the blade holder and the bowl of the kettle.

The blade is held in place by a securing pin 20 which has hooked ends 22 and 24, the former passing through aligned openings 26 in the blade holder and blade, and the latter being retained in a notch in the outer surface of the end piece 12 of the blade holder. As in the case of the blade shown in Figures 2 to 5, the tip 34 of the blade has a chamfer so as to present a sharp edge.

In manufacturing the scraper blade of each of the embodiments described above, the composition supplied to the injection moulding machine contains metallic particles in the form of filaments. The composition may consist of a mixture of conventional thermoplastic, nylon/plastics granules together with modified thermoplastic, nylon/plastics granules, each of the modified granules having embedded in it one or more stainless steel filaments. When the granules melt during the injection process, the filaments are distributed throughout the molten plastics, nylon or nylon-type material and hence throughout the scraper blade as it is moulded. The concentration of filaments is such that any pieces (or at least any pieces above a predetermined size) of the scraper blade which break off as a result of wear will incorporate one or more filaments and will be detectable by a metal detector arranged at the end of the line through which the food products are fed after the cooking process. A quantity of foodstuff contaminated in this way, having been identified, may be extracted and disposed of. Alternatively the pieces may be attracted out of the food product by means of magnets. In the case where a metal detector is used to identify contaminated quantities of food, the filaments used may be of nonferrous metal.

The modified nylon/plastics granules may be generally elongate in form, each with a diameter of substantially 2 mils and a length of approximately 5 to 6 mils, and through which a stainles steel filament or filaments extend lengthwise of the granule. The filaments may have a diameter of less than 1 mu and a length of approximately 5 to 6 mit, and may be longer than the granules that contain them. The composition used for moulding the scraper blade may include between 6% and 10% by weight of the modified granules, and advantageously 6.6 % by weight of the modified granules in order to achieve a sufficient distribution of the filaments within the scraper blade.

nylon/plastics granules which contain stainless steel or other metallic filaments, provided that the proportion of nylon/plastics to metal is appropriately increased.

In the Claims which follow, nylon and nylon-type materials are intended to fall within the scope of the term "plastics".

Claims

1. A scraper blade for a cooking vessel, the blade being moulded from plastics material and having metallic particles distributed within it.

2. A blade claimed in claim 1, wherein the particles are of ferrous metal in the form of filaments having a diameter of less than 2 mu and a length of approximately 5 to 6 mu.

3. A blade as claimed in claim 2, wherein the filaments have a diameter of less than 1 mu.

4. A composition for use in the injection moulding of scraper blades for a cooking vessel, comprising thermoplastic granules, at least some of which incorporate metalli filaments.

5. A composition as claimed in claim 4, wherein at least the granules which incorporate metallic filaments have a diameter of approximately 2 ml! and a length of approximately 5 to 6 mu.

6. A scraper blade as claimed in any of claims I to 3 or a composition as claimed in claim 4 or claim 5, wherein the filaments are stainless steel filaments.

7. A scraper blade assembly comprising a holder having a support pin at a first of its ends and receptacles at its edges adjacent a second of its ends, the receptacles receiving the edges of a plastics scraper blade, and a securing pin having hook-shaped ends, one of which is engaged with said first end of the holder and the other of which is engaged in aligned openings in the blade and holder adjacent said second end.

8. A scraper blade or assembly substantially as hereinbefore described with reference to and as illustrated in Figures 2 to 5 or Figures 6 to 8 of the accompanying drawings.

9. A composition for injection moulding of a scraper blade substantially as hereinbefore described.