The present invention relates to an arrangement in incine¬ rators. The incinerator to which the invention relates is primarily intended for incinerating waste in situations where total destruction is required. One particular field of application in this regard is the on-site destruction of oil and not-readily combusted material, by which is meant the total destruction by burning of material on the spot in which it is found. Naturally, the incinerator is also capable of burning other material waste, such as domestic refuse, forestry waste, etc..

The incinerator is intended primarily to solve the problem of burning material in such open spaces as those where the formation of soot particles is not desirable and where the risk of accidental fires may be high. The incinerator shall also be readily transportable, while enabling a large quan¬ tity of material to be burned in relation to the size of the incinerator per unit of time.

It has been found extremely difficult to destroy on-site such materials for example as oil-residue agglomerations created by water-carried oil slicks. The transportation of such agglomerations, which often include oil-saturated seaweed and other oil-saturated materials, to central or large incinerator depots is extremely costly. Moreover, such materials are difficult to burn effectively, due to their high water content. The risk of starting unintentio¬ nal fires is also high, when burning oil-wastes on open fires in exposed areas. Associated with those problems is the reluctance to subject the surrounding countryside, coastline, off-shore islands etc. to the effect of environmentally harmful and often troublesome non-com¬ busted or partially burned oil-products and other mate¬ rials. In addition, an on-site incinerator as hereinbe- fore defined must be mobile in the sense that it can be transported readily to and from the various sites.

The present invention solves these problems and fulfils the aforesaid objects.

Accordingly, the invention resides in an arrangement in incinerators of the kind which incorporate an elongated incinerator chest comprising a lower bottom and an upper bottom which is spaced fromthe lower bottom and forms a bed for supporting material to be incinerated,which upper bottom has provided therein apertures through which com- bustion air introduced into the space between the upper and lower bottoms flows this arrangement being charac¬ terized by theprovision of a hood which extends from one long side of the chest up over the chest, in spaced rela¬ tionship with the upper edge of the chest, and down to- wards the opposite long side of the chest, where the hood is provided with an air-slot which faces the upper bottom of the chest and which is intended for the supply of secon¬ dary air of combustion, there being formed between the upper chest-bottom and the hood a space which is open at least between the respective upper edges of the two remaining, mutually opposite sides of the chest and the side edges of the hood.

The invention will now be described in more detail with reference to an embodiment of the invention as shown in the accompanying drawing, where

Figure 1 is a sectional view of one embodiment of an incinerator according to the invention taken on the -line B-B in Figure 2;

Figure 2 is a sectional view taken on the line A-A in

Figure 1; and Figure 3 is a sectional view which corresponds to the view of Figure 1 and which illustrates a further embodiment of an incinerator according to the invention.

In Figure 1 there is shown an incinerator arrangement 1

constructed in accordance with the invention and compris¬ ing an elongated receptacle which has an upper bottom 2 and a lower bottom 3, and which can thus be said to form a fire chest. The upper bottom 2 is lowered in relation to the upper edges of the long sides 4,5 of the chest.

The upper bottom 2 has formed therein a plurality of aper¬ tures 6,7,8,9 through which primary air of combustion is intended to flow. Connected to the interior of the chest is a pipe-connection 10 or like device, through which air required for combustion is delivered to the chest by way of a fan 44. The upper bottom 2 thus serves as a bed for the material to be burned. Such material is shown schema¬ tically in Figures 1 and 2 by a broken line.

The incinerator according to the invention also incorpora¬ tes a hood 11 which extends from one long side 4 of the chest 2, up over the chest in spaced relationship with the upper edge thereof, and down towards the opposite long side 5 of the chest.

The end of the hood 11 spaced from the aforesaid long side 5 of the chest presents an air slot 12 which is directed towards the upper bottom 2 of the chest and which is intended for supplying secondary air of combustion to the combustion process.

Thus, there is formed between the upper bottom 2 of the chest and the hood 11 a space 13, which is open at least in the region between the respective upper edges of the two remaining, mutually opposite sides 14,15 of the chest and the side edges 16,17 of the hood 11. It can thus be said that the "end-walls" are open.

According to one preferred embodiment of the invention, the whole or a part of the hood is double-walled and has twin plates 18,19 which are spaced apart to form a cavity therebetween. This cavity is closed along the side edges 16,17 of the hood and opens at one end thereof into the air slot 12. The other end of the cavity connects with

a pipe-connector 20 or the like, which'is connected to the first-mentioned pipe-connector 10 via a channel 21, or alternatively is connected directly to a fan, not shown, therewith to deliver air to the air slot through the slot-like cavity.

In accordance with a preferred embodiment, the hood is hinged to the upper edge of the said one long side 4 of the chest . as exemplified by the hinge means 22. This enables the hood to be readily lifted, when charging the incinerator with material to be burned therein. In addition, such a hinge arrangement enables adjustments to be made to the opening 23 defined by the free edge 24 of the hood and the upper edge of the other long side 5 of the .chest.

When seen in section, parallel with the side edges 16,17 of the hood, i.e. the section shown in Figure 1, the hood presents preferably a planar upper surface 25 adjoined by outwardly and downwardly extending hood-parts 26,27.

Figure 3 illustrates a further embodiment of an incinerator according to the invention in which the hood, here referen¬ ced 28, is of different construction to the hood shown in Figures 1 and 2. The hood 28 of the Figure 3 embodiment presents an air-slot 29,30 along both its long sides.. Each of the air-slots faces in towards the upper bottom 2 of the chest 1.

In other respects the incinerator 1 is the same as that described with reference to Figures 1 and 2, and hence the various incinerator components are designated with the same references as corresponding components of the first-described embodiment. The hood 28 of the Figure 3 embodiment is preferably also double-walled and is provi¬ ded with a pipe-connector 31 through which air is delivered from a fan 45 to the air-slots 29,30 via the slot-like cavity formed by the double-walls. The hood

28 may be made raisable and lowerable, in order to facilitate charging of material to be burned. The hood of the Figure 3 embodiment also presents a planar upper surface 32 and adjoining downwardly and outwardly sloping hood parts 33,34.

The single arrows drawn in the Figures illustrate the directions of the primary and secondary air flows. The double arrows illustrate the pattern of the smoke gases generated during combustion.

The incinerator is suitably made entirely from sheet metal having a thickness compatible to the size of the incinerator.

The incinerator may, of course, be given any desired size, depending upon the use to which it is put. For example, an incinerator chest having breadth x length x height measurements of 1.8 m x 3.0 m x 0.8 m and a hood

3 of commensurate size will burn about 4 m of water- saturated waste per hour. ^" The incinerator is thus highly effective in relation to its size.

The provision in the hood 11,28 of either one or two air-slots 12; 29,30 which face towards the upper bottom 2 of the incinerator chest results in the creation of powerful turbulence, as shown in the Figures by the double arrows. Naturally, in order to create this turbulence, it is necessary to supply sufficient air through the air slots. Since this turbulence can be readily discerned in operation, it is relatively simple to regulate the inflow of air to achieve desired turbu¬ lence conditions.

The incoming air is preferably divided, so that approxi¬ mately half ot the total amount of air supplied is fed through the upper bottom 2 and half through the air slots 12; 29,30. The turbulence 35; 36,37 created inwardly of

the air slots contains a considerable amount of secon¬ dary air. Due to the powerful turbulence created, this secondary air is mixed with the partially non-combusted hot flue gases rising from the fire hearth, therewith to completely burn all residual non-combusted materials and compounds present in the flue gases, to provide complete combustion.

In addition to the effect caused by the aforesaid turbu- lence, it is impossible for the non-combusted flue gases to be conducted through the apertures 23; 38 _/ 39, without having come into contact with the secondary air injected through the air slots.

In the Figure 1 embodiment the turbulence, or vortex, referenced 40 also contains considerable quantities of oxygen, which is also admixed with the turbulence, or vortex, referenced 41. Consequently, as with the Figure 3 embodiment, flue gases leaving ^' the incinerator chest at its end walls, as illustrated by the arrows 42,43, are substantially fully combusted.

It will be seen that because the hood is double-walled, the secondary air present in the cavity thus formed in the hood is heated prior to leaving through the air slots, by takingheat from the hood walls. The secondary air thus also serves as a coolant, for cooling the hood.

The whole of the incinerator chest, or a part thereof, may be thermally insulated if desired.

Full scale tests have shown that the gases leaving the incinerator contain substantially no combustible matter, i.e. the exit gases are fully combusted. As a result of the overlyinghood, the level of temperature within the incinerator chest is high, and therewith enables not- readily combusted materials, such as water-sodden plant residues, to be incinerated more easily.

The risk of secondary fires is reduced to a minimum, due to the fact that the fire in the incinerator is fully enclosed by the incinerator chest and the hood.

Moreover, as beforementioned, the burning capacity of the incinerator is high in relation to its comparatively small dimensions. This enables the incinerator to be given such small dimensions as to enable it to be transported in a small truck or lorry, or an average size boat, while still providing an incinerator capable of destroying considerable quantities of waste, such as oil and oil- saturated material in coastal areas.

The aforementioned problems are thus fully solved by means of the present invention.

The present invention is not restricted to the afore- described embodiments, and modifications can be made within the scope of the _. following claims.