GB2381766A

GB2381766A - Coating apparatus for buttering bread

Info

Publication number: GB2381766A
Application number: GB0127172A
Authority: GB
Inventors: Peter Bartlett
Original assignee: ADVANCED FOOD TECHNOLOGY Ltd
Current assignee: ADVANCED FOOD TECHNOLOGY Ltd
Priority date: 2001-11-12
Filing date: 2001-11-12
Publication date: 2003-05-14
Also published as: CA2505867A1; WO2003041503A1; EP1487276A1; GB0127172D0

Abstract

An apparatus for buttering bread slices 1 includes an applicator roller 2a to which is imparted a thin layer of spreadable butter-like material by means of a feed roller 5 which carries a much thicker layer of spreadable material formed thereon by virtue of a doctor blade 3a which is widely spaced from the feed roller (5), thereby eliminating risk of irregularities in thickness of the layer applied to the slices 1 as a result of the presence of debris trapped between the doctor blade and the feed roller. The rollers 2a,5 may rotate so that their contacting surfaces move in a counter current fashion.

Description

METHOD OF AND APPARATUS FOR COATING AN OBJECT

The present invention relates to a method of coating an object, for example of applying a thin spread of butter or the like to a slice of bread, and also to an apparatus for coating an object.

Traditionally there are two main methods of buttering bread by automated equipment. One known method is contact buttering in which an applicator such as a roller, loaded with softened butter, contacts the bread slice passing under the applicator so as to apply butter to the bread surface. The thickness of the layer of butter on the applicator member, usually the roller, is controlled by a doctor blade defining with the applicator surface a gap having the appropriate thickness for the butter layer. The disadvantage of contact buttering is that crumbs can stick to the applicator member and can then clog the gap between the doctor blade and the applicator member, resulting in inaccurate butter application.

The second known method is non-contact buttering in which butter is sprayed or thrown onto the surface of a slice of bread, either from a nozzle through which the butter is pumped or from a spinning disc. With the spinning disc method, softened butter is pumped onto the disc and the effect of centrifugal force flings the butter off the edge of the disc and onto the slice of bread passing beneath the disc.

It is an object of the present invention to provide a contact coating system which overcomes the problem of debris accumulating in the gap between a doctor blade and an applicator member and then interfering with the uniformity of application of the coating to the member.

According to one aspect of the present invention there is provided a method of applying a coating to a passing object, comprising forming a layer of coating material on a moving applicator member, and transferring the coating material from the applicator member to an object to be coated, wherein the layer applied to the applicator member is formed by a means of a doctor blade which is stationary relative to the applicator member, characterised in that a moving feed member is used to apply a layer of coating material to the applicator member and is loaded with

a layer of coating material by virtue of passing close to said doctor blade; and in that the thickness of the layer applied to the feed member is greater than the thickness of the layer which it applies to the applicator member.

Preferably the object to be coated is a slice of bread and the coating is of butter, margarine or other spread which is held in a reservoir and released on to the feed member in the form of a relatively thick layer which is then transferred in the form of a relatively thin layer on to an applicator member which in turn applies the layer to the object.

A further aspect of the present invention provides apparatus for applying a coating to an object, comprising means defining a path for the object to be coated, a coating member arranged to move closely past said path to contact an object moving along said path, and means, including a doctor blade, for applying coating material to said applicator member, characterised in that the means for applying coating material to the applicator member further includes a feed member mounted for movement past said doctor blade and past the path of movement of the surface of said applicator member, such that the distance between the doctor blade and the feed member at the point of closest approach therebetween is greater than the distance between the feed member and the applicator member at the point of closest approach therebetween.

Preferably the applicator member is a roller which is driven for rotation relative to the path of a passing object to be coated. More preferably the feed member is itself a roller which rotates with its surface moving past the doctor blade so that coating material held back by the doctor blade can be released as a relatively thick layer on to the surface of the feed roller and can then be transferred as a relatively thinner layer on to the applicator roller. Desirably the rate of rotation of the feed roller is variable in order to control the flow rate of coating material to the surface of the applicator roller.

Suitably the feed roller and applicator roller rotate in the same direction so that the surfaces of the feed and applicator rollers at their closest point move in opposition to one another. The object to be coated can move relative to the applicator roller such that the direction of motion is either co-current with the surface

of the applicator roller or counter current therewith, at the point of closest approach.

Advantageously the rate of rotation of the feed roller is less than that of the applicator roller. More advantageously the surface speed of the feed roller is less than that of the applicator roller.

In order that the present invention may more readily be understood the following description is given, merely by way of example, with reference to the accompanying drawing in which: Figure I shows a side elevational partly schematic, view of a conventional bread buttering apparatus in use; and Figure 2 is a corresponding view of a bread buttering apparatus in accordance with the present invention.

Referring now to the drawing, Figure 1 shows a conventional contact buttering system with a bread slice 1 moving leftwardly past a clockwise-rotating applicator roller 2 such that, at the point of closest approach of the bread slice to the applicator roller 2 (the bottom of the circular path of travel of the surface of the applicator roller 2), a coating of butter, margarine or other spreadable material is transferred from the applicator roller to the bread slice 1.

A doctor blade 3 is positioned in the upper portion of the path of travel of the surface of the applicator roller and holds back a reservoir 4 of butter or the like which can gradually pass through the gap between the doctor blade 3 and the applicator roller 4 in the form of a layer on the surface of the roller 2. During the further clockwise rotation of the applicator roller 2 this layer is applied to the bread slice 1, but at the same time any loose crumbs or seeds on the surface of the bread slice 1 will be conveyed further round in the clockwise direction to arrive at the build-up 4 of butter or the like where the seeds will mingle with the butter and will be capable of entering the relatively narrow gap between the doctor blade 3 and the applicator roller 2 and will there result in unevenness of the layer passing between the feed 3 and the roller 2, thereby leading to a less satisfactory layer on the bread slice 1.

In accordance with the present invention, illustrated by way of example in Figure 2, there is an additional feed roller 5 with which the doctor blade 3a

cooperates, and the gap between the doctor blade 3 and the feed roller 5 is greater than that between the doctor blade 3 and the applicator roller 2 in Figure 1 such that a much thicker coating (now shown) is applied to the cylindrical surface of the feed roller 5 of Figure 2 than is applied to the cylindrical surface of the applicator roller 2 in Figure 1.

The relatively thick layer of butter on the feed roller only needs to move slowly round to the point of closest approach between the feed roller 5 and the applicator roller 2a in Figure 2 in order to provide, on the cylindrical surface of the applicator roller 2a, a layer which will have substantially the same thickness as that on the applicator roller 2 of Figure 1.

In the case of the apparatus of Figure 2, where seeds or loose crumbs might be entrained by the applicator roller 2a and pass forward in a clockwise direction they will eventually arrive at the point of closest approach between the applicator roller 2a and the feed roller 5 where the opposing directions of motion of the cylindrical surfaces of the two rollers will transfer the seeds and crumbs from the applicator 2a onto the feed roller 5, to pass in a clockwise direction around the axis of the feed roller 5, but this time to pass cleanly through the gap between the feed roller and the doctor blade 3a, which is much wider than the gap between the applicator roller 2a and the doctor blade 3 in Figure 1. Hence there will be no question of seeds and crumbs building up in the build-up 4 of butter or the like in Figure 2 and causing irregularities in the thickness of the layer 4a on the feed roller 5. Any such crumbs or seeds will simply pass further in the clockwise direction to arrive at the point of closest approach between the feed roller 5 and the applicator roller 2a in Figure 2 where they will be entrained to transfer from the cylindrical surface of the feed roller 5 to the cylindrical surface of the applicator roller 2a and be driven on the surface of the applicator roller to arrive eventually at the passing bread slice 1. They will have substantially no effect on the quality of the butter layer applied to the bread slice 1.

Although the applicator members are described as being in the form of continuously rotating rollers, the rollers could be caused to index in rotation rather than to rotate continuously, and indeed the applicator member need not be in the

form of a roller 2a, nor need the feed member be in the form of a roller 5. Other constructions of feed member and/or applicator member which nevertheless exhibit the difference in the approach distance of the feed member to on the one hand the widely spaced doctor blade 3a and on the other hand the closely spaced applicator member 2a can be evident.

Although the above description refers to applying butter to a slice of bread, the slice can be replaced by any other material requiring application of a coating, for example scones or toast, and likewise the material to be applied as a coating may be any spreadable material normally spread on bread, for example margarine, other spreadable fat, peanut butter or honey.

Claims

1. A method of applying a coating to a passing object, comprising forming a layer of coating material on a moving applicator member, and transferring the coating material from the applicator member to an object to be coated, wherein the layer applied to the applicator member is formed by a means of a doctor blade which is stationary relative to the applicator member, characterised in that a moving feed member is used to apply a layer of coating material to the applicator member and is loaded with a layer of coating material by virtue of passing close to said doctor blade, and in that the thickness of the layer applied to the feed member is greater than the thickness of the layer which it applies to the applicator member.

2. A method according to claim 1 wherein the feed member is a rotating roller whose surface passes the stationary doctor blade, and defines a gap between it and the doctor blade which is greater than the thickness of coating to be applied from the feed roller to the applicator member.

3. A method according to claim I or claim 2, wherein the applicator member is a rotating applicator roller which rotates in a direction such that its cylindrical surface moves closely past the surface of the feed member to entrain from the feed member a layer of coating material which is thinner than the layer carried by the applicator member.

4. A process according to either of claims 2 and 3, wherein the movement of the surface of the applicator member is counter current to that of the feed member and has a magnitude which is greater than the magnitude of the surface speed of the feed member.

5. A method according to any one of the preceding claims, including the step of varying the speed of movement of the applicator member in order to control

step of varying the speed of movement of the applicator member in order to control the rate of application of coating material to the applicator member.

6. A method according to any one of the preceding claims, wherein the object to be coated is a slice of bread in a succession of such slices moving past the applicator member and the coating material is a spreadable coating such as butter or margarine.

7. Apparatus for applying a coating to an object, comprising means defining a path for the object to be coated, a coating member arranged to move closely past said path to contact an object moving along said path, and means, including a doctor blade, for applying coating material to said applicator member, characterised in that the means for applying coating material to the applicator member further includes a feed member mounted for movement past said doctor blade and past the path of movement of the surface of said applicator member, such that the distance between the doctor blade and the feed member at the point of closest approach therebetween is greater than the distance between the feed member and the applicator member at the point of closest approach therebetween.

8. Apparatus according to claim 7, wherein said applicator member is an applicator roller and the path of the object to be coated is tangential to said applicator roller.

9. Apparatus according to claim 7 or claim 8, wherein said feed member is a feed roller which rotates to carry coating material from said doctor blade to the point of closest approach of the feed roller and the applicator member to transfer said coating material to the applicator member.

10. Apparatus according to claims 8 and 9 as taken together, wherein the applicator roller and the feed roller rotate in the same direction so that their surfaces move in counter current fashion at the point of closest approach therebetween.

11. Apparatus according to claim 9 or claim 10, including means for varying the rate of rotation of the feed roller to vary the rate of application of coating material to the applicator roller.

12. A method of coating an object, substantially as hereinbefore described with reference to and as illustrated in Figure 2 of the accompanying drawings.

13. Apparatus for applying a coating to an object, substantially as hereinbefore described with reference to and as illustrated in Figure 2 of the accompanying drawings.