IE45495B1 - Improvements in or relating to ovens - Google Patents

Abstract

1530361 Bakers oven FUNDITOR Ltd 6 April 1977 [14 April 1976] 15198/76 Heading A2A A bakers oven has at least one oven chamber 2 with supports 6 for supporting a plurality of trays containing a bread mix, an exit port 11 at the top of the chamber and hollow walls at each side of the chamber with a plurality of slits 14 through which air is passed into the chamber, air circulating means 12 are disposed at exit 11 to circulate air from the exit through slits 14 in the walls, and heating means 15 heats the air in the oven as it is being circulated; the slits 14 in the side walls are located relative to the position of the trays so that air directed through the slits heats the under side of the trays and passes over the top of the bread to heat but not impinge on the bread mix.

Description

This invention has reference to ovens and has particular but not exclusive reference to ovens used primarily for baking loaves of bread.

Ovens for baking bread may take many forms.

Ususally such ovens are batch ovens which may be gas or oil fired or may be electrically heated. Such batch ovens are usually located within the premises of a bakers shop and are constructed of brickwork or metal but often they are inefficient in relation to the amount of heat wasted in baking the loaves. Furthermore, bread ovens may he 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.

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 is less wasteful of heat than ovens used heretofore through more efficient utilisation of heat resulting from air circulation.

It is also an object of the present invention to provide an oven which can be suitably used as an industrial bakers oven or as an. oven located 48483 within tho promises of a bakers shop.

According to the present invention a bread baking oven comprises at least one oven chamber with supports capable of locating a plurality of trays which receive a bread mix, an exit port on the roof ol' t he t hainber 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 walls to direct the air through the slits in the hollow walls and means for heating the air in the oven as it is being circulated, wherein the slits in the side walls are so located iclalive in lh<> position of the trays that the aii directed through the slits heats the underside of ihe trays and passes over the top of the bread to heat, but not impinge upon the bread mix.

Preferably the heating means comprises electrical heating elements disposed in the hollow walls of the ovens and the air circulating means is disposed adjacent the exit in the roof of the oven.

Conveniently a plurality of doors are mounted in the front of the oven pivoted about their lower ends to he retained in an open horizontal position. 43499 Ovens in accordance vzith the invention will now be described by way of example with reference to the accompanying drawings wherein: Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figures to 11 Figures to l4 is a front view of the oven, is a side view of the oven, is a diagrammatic view of the oven taken from the front of the oven, is a sectional view of the side wall, is a view of the roof of the oven, is a view of the floor of the oven, are detailed views, and, are views of a modified oven.

Referring to Figs. 1 and 2 of the drawings, the oven 1 shown consists of two chambers 2 separated by an isolating dividing wall 3 and each having an outer wall 4, a plurality of doors 23 are fitted to the front of the oven and each door pivots downwardly as is hereafter described. A supporting framework 5 which forms part of the side wall 4 consists of eight (Figs, 3 & 4) supporting pillars extending from the front to the rear of the oven and each pillar has a plurality of flanged bracket es-ass supports ί· secured to it (sue ,il;.> iitt. ' ϊ r ; flanged supports extend outwardly in a iw.rarif.!. direction from the framework 5, aa-l are : i on-;itudiiially along the aid,-- ,.f ii-ι ct..«fib.-, ~ 2 5 and their <.pper surface is shape < :-, r.i.:· : orc a knife edge 6a (fig. '>1 wi.i a pr· · id,·.' ., for trays?inserted into the ovto, ·,: s:·,·.... and as shown in Fig. 10 bracl.pl sup:·-·, -: -1/ may hove a plurality of ball bearing.- i7c r lu in lhe bracket,which bracket is hec«r,. J .-s by 17b to the framework 5.

The trays 7a are of a size which can te irsarisd into the oven to slide on the knile «Ige -uppert* on the complementary brackets on opposite sides cf the chambers and at the same height. These trays. sometimes referred to as base sheets, are stiiable for receiving a plurality of portions of dough mixture for bread baking. These dough portiers have been proved so that tho dough mixture has been allowed to rise prior to baking in the n=—n described.

The outer side walls 4 of each chamber also he/e insulating wall parts 4a whereby a hallow part is formed within the wall 4 between the insula t in-t wall Dart 4a and the metal framework 5 of the chamber. Likewise the upper ceiling chambers 2 consist of a metal ceiling part 9 spaced from ihe upper 48495 insulating roof part 10, so that a hollow part is formed between the outer insulation 10 and metal ceiling part 9- This hollow part is in communication with the hollow part between the insulating wall 4a and framework 5.

An aperture 11 is formed centrally of each chamber 2 and air circulating means 12 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 10 and metal ceiling part 9.

This hollow part constitutes a plenum chamber.

As shown best in Fig. 5» the air circulating means 12 propels air derived from the centre part of the oven into metal ducts 13 which direct air to the hollow IS parts at the sides of the chambers. A plurality of horizontally arranged longitudinal slits l4 is formed in the metal framework 5 of the chanters and these slits which extend from fche front to the rear of tho chambers are formed immediately underneath the respective bracket supports 6 on which the trays are supported in the oven. The slits are located relative to the position of the trays on the bracket supports so that the air ducted through the slits impinges on the under25 sides of the trays to heat these undersides and 4S4SS passes over the tops of the loaves of bread but without impinging on the bread or the bread mix, thereby the bread is unlikely to become burnt. Λ plurality of electric heating elements l.r> are arranged within tho hollow centre walls of These heating elements extend in a substantially horizontal 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 he provided in the hollow parts of the outer side walls 4. These elements serve to heat the air being forced in circulation around the oven. An extractor mechanism 50 is fitted above the oven.

A probe (not shownXis fitted into the plenum chamber of the oven and this probe is connected into an electrical control circuit 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 2, the temperature of the two chambers 2 of the oven may be 48498 set at different temperatures.

In the bottom of each chamber are located a pair of trays 20 (Fig. 6) and each of these trays contains a trough 21 to receive water.

This water is used if necessary when the oven has been operated for some length of time and the air in the oven has become too dry. This serves to prevent weight loss and/or the bread being formed with surface cracks during baking.

In an alternative arrangement when it is required to moisten the bread to give the crust a glazed appearance, the water may be injected into the oven through sprays which are operated for a short period during the initial baking of the bread.

The bracket supports 6 which hold the trays 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. Λ space is required between each bracket at the top of the loaves of bread underneath them so that the air can circulate through the slits 14 in the metal framework 5 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 burned. 4549S The doors 23 (Figs· 1 & 2) are fitted to the front of the oven. A door is fitted f οχ each pair of brackets to receive two trays and corresponds to the position of respective oven chambers. Each door is piloted about a binge 24 and so airanged 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 6 as shown in dotted lines Fig. 7- This allows tray to be brought out of the oven and supported partly on the bracket and partly oti the door in a horizontal position so that,if required, the partly baked loaves can be It gated,for example, by having flour dusted over them. Λ spring 25 is arranged ext opposite sides of each door (Fig. 5) and is mounted between one end of a bracket 2f>, which moves with tiie door ami at the other end to a flange 27 secured lo the body ol the oven. The spring is so arranged that as the door is passed from the open to the closed position the spring passes over its dead centre position so that the door will be urged to either its open or closed position.

Although the brackets are normally disposed a sufficient distance apart suitable for bread making the oven may be adapted for use in baking rolls or like small produce. For this use a plurality of additional steel brackets 28 (Fig. 9) are provided between adjacent brackets 6. These additional brackets pivot from an in-use position, in which they are in a horizontal position to support the trays bearing the dough mixture, and the out'-of-use position, in which the brackets are folded in closely adjacent to the wall of the oven, where they are held in that position by a magnet. 28a.

An additional slit 29 is formed beneath each of the brackets 28. An extension flange 3° is located on the side of the bracket beyond the hinge and the slits 29 are closed by the extension fLange part 3θ of the bracket engaging with a closure part bracket 31, when the bracket is in its out-ofuse position. A tray 7a is supported between complementary brackets at opposite sides of the chamber 2 as shown in chain dotted lines in the 20 righthand chamber 2 (Fig. 3). As shown in Fig.3 of the drawings the brackets on the lefthand side of the Figure are shown in the closed position, whereas, on the righthand side they are shown in the open position with trays 7a supported on some of 2g the brackets.

Referring to Fig. 11 of the drawings there is shown mechanism to feed drops of water into the oven to provide the required water in the oven if it 4S49S becomes too dry. This mechanism includes a copper pipe water inlet 32 ai the lower end of the mechanism which is connected to a control valve 33. At. the outfeed side of the control valve is a tee junction 34 which permits water to be passed to alternate supply pipes , and each of these alternate supply pipes which supplies water to the respective chambers 2 has its own control valve 33. By this means the rate of flow of water to the chambers can be controlled. If desired the valves 33, 33 can be controlled by an electric current acting under the control of humidity measurement means in the chambers 2.

In the modified form of the invention shown in Figs. 12 to 14 there is shown an oven 4o consisting of a single chamber 2 having an outer side wait 4 including a framework 3 spaced from outer insulating walls 4a wheeby a hollow part is formed between the side wall and the insulating wall.

The upper ceiling of the chamber 2 consists of a metal ceiling part 9 spaced from the upper insulating roof 10, so that a hollow part is formed between the ceiling part 9 and the roof 10. This hollow part is in communication with the hollow part between the side wall and the insulating wall. An aperture is formed in the ceiling part 9 and air circulating moans (similar to the air circulating means 12 shown in Fig.3)is 45498 positioned at the exit of this aperture to draw air out of the chamber into the hollow ceiling part. Metal ducts direct this air to the hollow parts at the opposite sides of the chamber and electric heating elements 15 are positioned in the hollow part between the framework 5 and the insulating walls 4a.

A plurality of horizontally arranged slits l4 are provided in the framework 5 of the chamber and extend from the front to rear of the chamber.

The floor of the chamber is formed with four channels 41 extending from the front to the rear Of the chamber 2 and a pair of these channels serve as guideways for a trolley 42. This trolley has wheels 43 which are located in the channels 4l and a framework 44 with supports 45 at the sides of the trolley framework to receive trays 7 oh which bread mixture can be positioned. It is important that the supports are so positioned on the framework of the trolley so that the trays when positioned on these bracket supports are located just above the horizontal slits in the chamber framework, so that the heated air ducted through the sLits passes just beneath the trays to heat the trays and passes over the top of the bread hut does not inpinge upon or come into contact with the bread or the bread mix.

The front of the oven is closed by two pans! doors 46 each having a glass panel 47. The doors are respectively closed by means of a closing handle 48 and a feeler mechanism(nofc shes-jn) for each deer to lock the door, and to serve as a control means for the electric circuits of the oven.

An extractor fan 5θ is fitted above the oven.

The joints in the framework and walls and other parts of the oven are welded together and in view of the hot moist content of the atmosphere of the oven it is necessary to protect these joints. This is achieved by covering the joints with protective compound such as that sold under the Trade Mark ARBOSIL 1081.

Claims (10)

1. A bread baking oven comprising at least one oven chamber with supports capable of locating a plurality of trays xvhich receive 5 a bread mix, an exit port 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 10 port through the hollow wallsto direct the air through the sLits in the hollow walls and means for heating the air in the oven as it is being circulated, wherein the slits in the side walls are so located relative to the position of the trays that the air 15 directed through the slits heats the underside of the trays and passes over the top of the bread to heat but not impinge upon the bread mix.

2. An oven according to claim 1 has a plurality of doors positioned relatively to the position of the 20 trays whereby the opening of one of the doors opens an area between adjacent trays.

3. An oven according to claim 2 wherein each door is mounted at the front of the oven and pivoted about its lower end and capable of being retained in 25 an open longitudinal position. 4. 8495

4. An oven according to claims 2 and 3 wherein each door in its open horizontal position has its upper face in Line with tho upper surface of the tray supports to facilitate withdrawal of the trays from the oven.

5. An oven according to any one of the preceding claims having heating elements disposed in the hollow walls of the oven.

6. An oven according to claim 1 or 5 wherein the air circulating means is disposed adjacent the exit in the roof of the oven.

7. An oven according to any one of the preceding claims having a water supply to prevent the air in the oven becoming too dry.

8. An oven according to claim 7 wherein the water supply comprises a mechanism to feed drops of water to the oven with ap associated valve to control the rate of flow of water to the oven.

9. An oven according to claim 1 wherein the supports are provided on a trolley capable of being moved into and out ol' the oven.

10. An oven according to claim 9 wherein thi' floor of tho oven has a plurality of channeLs which serve as guideways for the trolley.