WO2003001915A1

WO2003001915A1 - Method and apparatus for coating only a selected surface of an object

Info

Publication number: WO2003001915A1
Application number: PCT/GB2002/002996
Authority: WO
Inventors: Peter Bartlett
Original assignee: Advanced Food Technology Ltd.
Priority date: 2001-06-29
Filing date: 2002-06-28
Publication date: 2003-01-09
Also published as: GB0115993D0; GB2376906A

Abstract

Apparatus for buttering a slice of bread is able to apply butter from a non-contact buttering head, in this case in the form of a spinning disc 5, without contaminating the edges, la, 1 b of the slice, by arranging for an acute angle a between the direction of flow of a butter curtain 3 and the plane of the slice 1 as the leading edge 1 a enters the curtain, and an obtuse angle ß between the direction of the butter and the plane of the slice as the trailing edge 1 b leaves the curtain. In the preferred embodiment the slice is inclined downwardly on passing from an in-feed conveyor to a forwarding conveyor at a lower level, to generate the angle a, and virtue of the butter flow is non-vertical with an orientation to ensure that the flow does not contact the trailing edge 1b as the slice 1 leaves the curtain 3.

Description

METHOD AND APPARATUS FOR COATING ONLY A SELECTED SURFACE OF AN OBJECT

The present invention relates to a process for coating only a selected surface of an article, and in particular the invention can be applied to the buttering of bread where butter is required to be placed on a major face of a slice of bread but not on the edges where the bread crust arises.

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. However, current non- contact methods have the disadvantage that not only the exposed bread face but also the crusted edges become covered with the butter so that particularly the front edge of the slice of bread becomes contaminated with the butter.

It is an object of the present invention to provide a method and apparatus for applying coating material only to a selected face, for example the exposed bread face of a bread slice, without inadvertently applying butter to other faces of the article. Accordingly, one aspect of the present invention provides a method of coating only a selected face of an object without applying coating to an adjacent surfaces, comprising creating relative movement between the object and a mass of coating material moving along a path, providing an acute angle between the direction of movement of the moving mass of coating material and the plane of the selected face to be coated, as the article comes into contact with the coating material, and creating an obtuse angle between the direction of movement of the mass of coating material and the plane of the selected face to be coated, as the article leaves the path of the moving coating material.

A second aspect of the present invention provides apparatus for coating only a selected face of a moving article comprising means for generating a flow of coating material along a path in a first direction, means for moving an object to be coated along a second direction transverse to the first direction so that a first end of said selected face of the object enters the path of the coating material before a second end opposite to the first end of the selected face, means for changing said first direction and/or said second direction as an object is fed through the path of the coating material, such that the direction of flow of the coating material as said first end of the selected face enters the flow is an acute angle such that the flow has a component of movement from said second end towards said first end of the selected face, and for altering said orientation as the second end of the selected face passes through said path of the moving coating material so as to provide that the direction of movement of the coating material has a component of movement from said first end towards said second end of the selected " face.

In order that the present invention may more readily be understood the following description is given, only by way of example, with reference to the accompanying drawings in which:-

Figure 1 is a schematic side elevation showing a prior art non-contact buttering apparatus; Figure 2 is a similar view showing a bread slice about to enter the curtain of liquid butter emanating from a spinning disc in apparatus according to the present invention; and

Figure 3 is a view showing the same bread slice of Figure 2 as it leaves the curtain of liquid butter.

As shown in Figure 1, the buttering head is a butter-flinging disc which rotates about a horizontal axis and emits a curtain of liquid butter which passes downwardly between the discharge end of a feed conveyor and the entry end of a forwarding conveyor which takes over the task of moving the bread slice after it has left the feed conveyor.

Figure 1 shows the prior ait arrangement in which a slice of bread 1 moves towards the downwardly moving curtain 3 of liquid butter being spun off a disc 5 rotating about a horizontal axis 7. The bread slice is being advanced by the feed conveyor comprising a belt 9 passing around two rollers one of which, 11, can be seen in Figure 1, and the bread slice passes off the left hand end of the feed conveyor to pass through the butter curtain 3 and onto the forwarding conveyor comprising a belt 13 passing around two rollers one of which, 15, can be seen in Figure 1.

It will be appreciated that as the leading edge la of the slice 1 enters the curtain 3 that leading edge will pick up butter from the curtain 3, and likewise as the trailing edge lb passes through the plane of the curtain it, too, can be contaminated. The intention is that only the upper surface lc should be coated with butter.

One embodiment of the present invention is illustrated in Figure 2 where there are various departures from the conventional apparatus shown in Figure 1. The important aspect of the method of the present invention is, however, that there is an acute angle formed between the direction of movement of the coating material, in this case butter, and the face being coated, in this case the upper face 1 c of the bread slice 1 , as the article enters the moving mass of coating material, namely the curtain 3 of butter. Furthermore, as the article leaves the moving mass of coating material the angle formed between the direction of the coating material and the plane of the face being coated should no longer be acute, but should be obtuse. This re-orientation is achieved in Figure 2 by having the belt 9 of the feed conveyor inclined downwardly at the end near the curtain 3 of butter and also having the rotation axis 7 of the disc inclined to the horizontal but by an angle of inclination which is less than that of the bread slice 1 so that when the bread slice 1 becomes horizontal on arriving on the belt 13 of the forwarding conveyor there is now an obtuse angle formed between the curtain 3 and the trailing edge lb of the bread slice.

The acute angle relevant to the entry of the bread slice into the butter curtain 3 is shown at in Figure 2 and the obtuse angle relevant to the passage of the trailing edge lb through the curtain 3 is shown at β in Figure 3.

Although in the embodiments shown in Figures 2 and 3 the angle of inclination of the bread changes with respect to a static direction of the moving mass of coating material (the butter curtain 3) it is alternatively possible for the direction of the moving mass of coating material to be changed relative to a surface to be coated (the upper face 1 c of the bread slice 1) which remains constant. Equally there could be some combination of these two actions, for example by also tilting the angle of inclination of the rotation axis 7 between Figure 2 and Figure 3, or by similar provisions in any other form of the apparatus.

In terms of the mechanics of the apparatus, the inclination of the belt run supporting the bread slice 1 at the point of entry into the butter curtain 3 is achieved by having an additional roller 19 over which the belt of the feed conveyor 9 passes, but with its upper surface lower than the upper surface of the above mentioned roller 11. Alternatively it would have been possible to add, in the apparatus of Figure 1, a small diameter roller to the right of the roller 11 shown in Figure 1, but at a higher level so that again the run of the conveyor belt 9 approaching the curtain 3 is downwardly inclined.

The achievement of the acute angle β in Figure 3 results from the inclination of the rotation axis 7 relative to a horizontally moving upper run of the belt 13 of the forwarding conveyor. This makes for a simple apparatus in that the forwarding conveyor can be identical to that of the conventional apparatus typified by Figure 1. However, it is equally possible for the angle of inclination of the bread slice to be such that the leading edge 1 a in Figure 3 is higher than the trailing edge, and then the rotation axis 7 could be maintained stationary and the acute angle β still achieved.

The precise means for applying the liquid butter to the spinning disc 5 are not essential to the present invention as these are well known in the art and need not be changed as a result of the modification to provide the non-contact coating apparatus of the present invention.

Claims

1. A method of coating only a selected face of an obj ect without applying coating to an adjacent surfaces, comprising creating relative movement between the object and a mass of coating material moving along a path, providing an acute angle between the direction of movement of the moving mass of coating material and the plane of the selected face to be coated, as the article comes into contact with the coating material, and creating an obtuse angle between the direction of movement of the mass of coating material and the plane of the selected face to be coated, as the article leaves the path of the moving coating material.

2. A method according to claim 1 wherein the change of orientation to provide the acute angle on entry of the object in the path of the coating material and the obtuse angle on leaving the path of the moving mass of coating material is achieved by varying the inclination of the surface to be coated.

3. A method according to claim 1 or claim 2 wherein the change of orientation from the acute angle on entry of the object in the path of the coating material to the obtuse angle on leaving the path of the moving coating material is achieved by altering the orientation of the direction of movement of the coating material along said path.

4. Apparatus for coating only a selected face of a moving article comprising means for generating -a flow of coating material along a path in a first direction, means for moving an object to be coated along a second direction transverse to the first direction so that a first end of said selected face of the object enters the path of the coating material before a second end opposite to the first end of the selected face, means for changing said first direction and/or said second direction as an object is fed through the path of the coating material, such that the direction of flow of the coating material as said first end of the selected face enters the flow is an acute angle such that the flow has a component of movement from said second end towards said first end of the selected face, and for altering said orientation as the second end of the selected face passes through said path of the moving coating material so as to provide that the direction of movement of the coating material has a component of movement from said first end towards said second end of the selected face.

5. Apparatus according to claim 4, wherein said means for generating movement of an object relative to the path of the coating material comprises an in-feed conveyor which advances the article off an end of that in-feed conveyor adjacent the path of the coating material, and a forwarding conveyor which entrains the article having passed through the path of the coating material, said in-feed conveyor being higher than said forwarding conveyor.

6. Apparatus according to claim 5, wherein said in-feed conveyor comprises a belt conveyor having an upper run which supports said object, with a downwardly inclined portion at the end of said upper run adjacent to the path of the coating material.

7. Apparatus according to claim 5 or claim 6, wherein said forwarding conveyor is a the belt conveyor having an upper belt run which is horizontal and is positioned below the plane of the upper run of said in-feed conveyor belt.

8. Apparatus according to any one of claims 4 to 6, wherein said means for generating a flow of coating material comprises a disc for spinning liquid butter to define a curtain of moving butter through which said object passes for coating of said face with butter.

9. Apparatus according to claim 7, wherein said means for generating a flow of coating material comprises a disc for spinning liquid butter to define a curtain of moving butter through which said object passes for coating of said face with butter.

10. Apparatus according to claim 9, wherein said disc rotates about an axis which is inclined to the horizontal such that the plane of the disc defines an angle with the horizontal so as to direct the flow of butter in a direction which is inclined to the vertical.

11. A method of buttering bread, substantially as hereinbefore described with reference to the accompanying drawings.

12. Apparatus for buttering one face of a slice, constructed and adapted to operate substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.