GB2038156A - Bakers oven - Google Patents

Abstract

A bakers oven has slits 10,12 etc. in the oven side wall 5 through which hot air is passed into the oven chamber 2, a curtain member 17 capable of covering the slits to prevent the passage of air through the slit, at least one cam member, e.g. comprising a bolt 18 and a roller 20, secured to the curtain member 17 and projecting from the curtain through a slot in the wall 5 into the path of the tray 21 being inserted into the chamber, whereby the action of passing the tray 21 into the chamber 2 engages the cam member to uncover the slit. <IMAGE>

Description

SPECIFICATION Improvements in or relating to ovens This invention has reference to ovens and has particular but not exclusive reference to ovens used primarily for baking loaves of bread but which may also be used for baking smaller items, for example, rolls, buns etc.

Ovens for baking bread may take many forms and this is referred to in the specification of our patent No. 1530361. Such ovens are usually batch ovens which may be gas or oil fired or may be electrically heated and which are usually located within the premises of a baker's shop and constructed of brick work or metal but often are inefficient in relation to the amount of heat wasted in baking the loaves. On the other hand bread ovens may be of the so-called industrial oven conveyor type which bakes a large number of loaves which have to be transported from the oven site to the shops.

In the specification of our Patent No. 1530361, there is described an oven suitable for use for baking bread and is in the form of a batch oven or for use as an industrial oven and which comprises at least one oven chamber with supports capable of locating a plurality of trays which receive a bread mix, an exit part on the roof of the chamber and a hollow wall at each side of the chamber, the hollow walls having a plurality of slits through which air is passed into the oven chamber; air circulating means to circulate the air from the exit port through the hollow wall to direct the air through the slits in the hollow wall; a means for heating the air in the oven as it is being circulated, wherein the slits in the side wall are so located relative to the position of the trays that the air directed through the slits heats the underside of the trays and passes over the top of the bread to heat but not inpinge upon the bread mix.

In such specification there is described a mechanism for temporarily supporting an auxilliary tray if the oven is required to be used for baking smaller items than loaves of bread, for example, rolls, buns etc.

It is an object of the present invention to provide an improved construction of oven.

It is another object of the present invention to provide an improved oven which may be utilized not only for the baking of bread but also for smaller items such as rolls or buns.

According to the present invention, a bread baking oven has a chamber with a hollow wall at one side through which hot air is conveyed, at least one slit in the said side wall through which hot air is passed into the chamber, a curtain member capable of covering the slit to prevent the passage of air through the slit, a cam member secured to the curtain member and projecting from the curtain through a slot in the wall into the path of the tray being inserted into the chamber whereby the action of passing the tray into the chamber engages the cam member to move the curtain to uncover the slit.

An oven in accordance with the invention will now be described by way of example with reference to the accompanying drawings wherein: Fig 1. is a front view of the oven with the doors removed, Figs 2 and 3 are views of part of the oven, and, Fig 4. is a perspective view of a tray for use in the oven.

An oven 1 according to the invention which is of the kind described in Patent Specification No.

1530361, consists of two chambers 2, separated by an isolating dividing wall 3 and each having an outer wall 4, a plurality of doors are fitted to the front of the oven and each door pivots downwardly. A supporting frameword 5 which forms part of the side wall consists of eight supporting pillars extending from the front to the rear of the oven and each pillar has a plurality of flanged bracket supports 6 secured to it.

These flanged supports extend outwardly in a horizontal direction from the framework and are located longitudinally along the sides of the chambers 2, which flanged supports provide a support for the trays 21 inserted into the oven.

The trays 21 are of a size which can be inserted into the oven to slide on the bracket supports 6 on the complementary brackets on opposite sides of the chambers and at the same height These trays, sometimes referred to as base sheets, are suitable for receiving a plurality of portions of dough mixture for bread baking. These dough portions have been proved so that the dough mixture has been allowed to rise prior to the baking in the oven described.

The outer side walls 4 of each chamber also have insulating wall parts 4a whereby a hollow part is formed within the wall between the insulating wall part4a and the metal framework 5 of the chamber.

Likewise the upper ceiling chambers consist of a metal ceiling parts 5a spaced from the upper insulating roof part 4b, so that a hollow part is formed between the outer insulation and metal ceiling part 5a.

This hollow part is in communication with the hollow part between the insulating wall and frame work 5.

An aperture 8 is formed centrally of each chamber and air circulating means 9 is disposed at the exit of this aperture to draw air out of the chambers and propel it into the hollow part between the insulation and metal ceiling part. This hollow part constitutes a plenum chamber.

The air circulating means 9 propels air derived from the centre part of the oven into metal ducts which direct air to the hollow parts at the sides of the chambers. A plurality of horizontally arranged longitudinal slits 10 is formed in the side metal walls of the chambers and these slits, which extend from the front to the rear of the chambers are formed immediately underneath the respective support bracket supports 6 on which the trays 21 are supported in the oven. The slits 10 are permanently open and are located relative to the position of the trays on the bracket supports so that the air ducted through the slits impinges on the undersides of the trays to heat these undersides and passes over the tops of the loaves of bread but without impinging on the bread or the bread mix,therebythe bread is unlikely to become burnt.

A plurality of eiectric heating elements 15 are arranged within the hollow centre walls of the ovenbetween the side walls and the insulating walls.

These heating elements 15 extend in a substantially horizontally direction and extend the full depth down the oven from the top thereof. Additional heating elements are provided in the upper part of the dividing walls and can also be provided in the hollow parts of the outer side walls. These elements serve to heat the air being forced in circulation around the oven. An extractor mechanism is fitted above the oven.

A probe is fitted into the plenum chamber of the oven and this probe is connected into an electric control ci rcuit to control the supply of electricity to the heating elements and thereby to control the temperature of the oven.

The control circuit (not shown) includes a setting mechanism whereby the temperature of the oven can be controlled. Of course if different kinds of bread are being baked in the two chambers the temperature of the two chambers of the oven may be set at different temperatures.

The bracket supports 6 which hold the trays 21 are spaced apart at a distance such that the trays can be accommodated so as to carry fully baked loaves of bread which are adequately spaced from the brackets and trays next above the loaves. A space is required between each bracket at the top of the leaves of bread underneath them so that the air can circulate through the slits in the side walls of the oven above the loaves without actually impinging on the loaves enabling the loaves to be given an even colour all over and reducing the risk of having the loaves burnt.

Doors are fitted to the front of the oven. A door is fitted for each pair of brackets to receive two trays and corresponds to the position of respective oven chambers. Each door is pivoted about a hinge and so arranged that when a door is in the open position it extends horizontally away from the front face of the oven with its outer surface in line with the upper surface of the bracket support. This allows a tray to be brought out of the oven and supported partly on the bracket and partly on the door in a horizontal position when being withdrawn. Although the bracket supports band trays 21 are normally disposed a sufficient distance apart suitable for bread making the oven may be adapted for use in baking rolls or like small items. In order to make use of the space available it is desirable to utilize the space between adjacent trays.

To enable this to be effected, and as shown in Figs 2 and 3 an additional set of slits are provided in the wall of the framework 5 and an additional set of slits 13 are provided in the framework 5 in the centre wall of the oven. The slits 12, 13 are additional to the slits 10 in the oven which are utilized for baking loaves of bread. Heated air likewise passed into the oven chambers 14 through the slits 12 and 13 into the oven chamber 14. Brackets 15, 16 constitute the upper and lower sides of the slits 12,13 and also serve to direct the heated air into the oven chamber 14.

On the rear of the wall 11 outside the oven chamber and normally so located as to cover the slit 10 is a curtain member 17. This curtain member is supported buy a pair of bolts 18 which pass-thrnugh the curtain member 17 and also pass through a slot 19 in the wall, one bolt 18 is located nearthe front of the oven and the other belt 18 is located towards the rear of the oven. Eadh slot 19 is extended in the vertical direction so that the bolt 18 is movable in a substantially vertical direction within the slot.

Rotatably mounted on the bolt 18 within the oven chamber 14 is a roller 20. This roller 20 is positioned close to the wall 11. A tray 21 is slidable on the pair of upper brackets 15 at the opposite sides of the oven chamber 14 which constitute the upper sides of the slits 12, 13. The tray 21 has a flange 22 at one side, and as shown in Fig 4 the forward end of the flange is inclined. As the tray slides on the bracket 15 abovetheslit 10 into the oven chamberthe leading inclined end 23 of the flange 22 engages the roller 20 on the belt 18 near the front part of the oven to raise the bolt in the slot 19 and also to raise the front end of the curtain to uncover the front end of the slit 10 in the outer wall 11.

Further movement of the tray into the oven causes the leading inclined end 23 of the flange 22 to engage the roller rotatably secured in the belt near the rear of the oven which causes the bar 18 to ride up in the vertical slot near the rearofthe oven to cause the rear end of the curtain to be raised to uncover the rear end of the slit 10 in the outer wall 11.

When the tray 21 is fully inserted into the oven the rollers will have fully ridden up the inclined end of the flange to cause the curtain to be fully raised to cover the slots 19 to permit an additional flow of heated air to flow overthe rolls or buns to be baked on the additional tray 21 inserted into the oven chamber. The heated air will continue to be circulated through the oven chamber to bake the contents on the tray underneath the additional tray and the contents on the tray above the additional tray which may hold a tray full of bread or a tray load of rolls, with a further additional tray located in a similar location directly above it.

In the embodiment described there is no curtain masking arrangement associated with the slit 13 on the righthand side of Fig. 1. It is found adequate to control the flow of heated air by having a single curtain masking arrangement (as shown on the left hand side of Fig 2) for each additional tray inserted between adjacent bread baking trays already in use in the oven. However, in certain circumstances it may be desirable to have a similar curtain masking arrangement on the right hand side of Fig. 1 as on the lefthand side.

The dough sometimes to be baked into rolls may either be loaded directly onto the tray 21 with the inclined end flange 22 or separate tins bearing dough mixture may be loaded onto the trays 21, already in position. The trays 21 are provided with downwardly extending flanges 24 at their rear edges to facilitate withdrawal of the trays from the oven.

Claims (6)

1. A bread baking oven having a chamber with a hollow wall at one side through which hot air is conveyed, at least one slit in the said side wall through which hot air is passed into the chamber, a curtain member capable of covering the slit to prevent the passage of air through the slit, a cam member secured to the curtain and projecting from the curtain through a slot in the wall into the path of a tray being inserted into the chamber whereby the action of passing the tray into the chamber engages the cam member to move the curtain to increase the slot.

2. A bread baking oven according to claim 1 having a plurality of permanently open slots extending longitudinally of the oven and a plurality of curtain covered slots having a curtain member and a cam member, the open slots being arranged alternatively one above the other with the curtain covered slots.

3. A bread baking oven according to claim 1 wherein each curtain member carries a cam member one near the front of the oven and one towards the rear of the oven.

4. A bread baking oven according to any one of the preceeding claims wherein each cam member constitutes a bolt secured to the curtain member on one side of the oven wall with a roller carried by the bolt, which passes through the wall, on the other side of the oven wall and engaged by the tray.

5. A bread baking oven according to any one of the preceeding claims wherein the tray has a flange at one side thereof and the flange has an inclined surface to raise the cam member.

6. A bread baking oven constructed and arranged substantially as herein described with reference to the accompanying drawings.