GB2253687A - An incinerator - Google Patents

Abstract

An offal incinerator comprises a refractory brick lined body (1) with a chimney (3) connected to the body (1) at one end and vent means at the other end. A gas burner (33) is located at the same end of the incinerator as the chimney (3) and a fan (35) may blow air or oxygen into the body (1) to assist burning of offal. Hot air circulates within the body and passes over a stainless steel baffle (40) before passing up the chimney (3). The baffle (40) is at red heat due to the burning, and contact between the baffle and the hot air causes secondary burning of the hot air which destroys smoke particles. Remaining smoke particles are destroyed in afterburner (72). After the offal has been partially burnt, the gas burner (33) may be switched off while the fan (35) continues to operate. The offal may continue to burn long after the gas burner (33) has ceased to operate. <IMAGE>

Description

AN INCINERATOR This invention relates to an incinerator adapted to dispose of offal and animal waste. It will be understood that the term offal may be used in this specification to mean any form of animal remains such as organs, raw meat, bones and whole or partial carcasses as well as any form of waste normally referred to as offal.

In livestock farming it is expected that in the normal course of events a number of animals will die of accidental causes, sickness or old age or for other unknown reasons. Generally these animals die on farm land and the farmer needs to dispose of the carcasses.

Historically knacker's yards, abattoirs and hunt's kennels have been willing to collect carcasses from local farms, pig units and poultry units. The hunt's kennels have in the past used as much meat off the carcasses as they needed to feed hounds kept and bred by the kennels. Excess meat, carcasses and meat or offal unsuitable for feeding to the hounds was traditionally sold on for a small fee to renderers who would render the offal into pet and animal food.

When an outbreak of bovine sponge form encephalitis (BSE) occurred concern was expressed firstly about using animal derived protein in livestock feedstuffs and secondly about the possibility of transfer of a BSE-like disease to pets through use of BSE contaminated offal in pet foods. Consequently renderers were no longer willing to pay for general offal as they could not safely render this offal into pet-food. Initially, however, the renderers continued to take offal and dispose of it, making a small charge for the service. At first this was simply a few pounds per ton of offal but has now risen to about 90.00 per ton. As an average hunt's kennels may have to dispose of about twelve tons of offal per month this represents a considerable cost in respect of a previously profitable activity.

Alternative means of disposal of offal have been considered. Burial is a possibility but the quantities involved pose some problems and also it may create an environmental hazard.

Another form of disposal considered is burning or incineration. Whilst this does adequately dispose of the offal problems have been encountered with incinerators producing large quantities of smoke and an odour which may be offensive to people living in the locality of the incinerator.

One known form of incinerator for burning offal has a cross section of approximately 3' by 3' and a height of about 7'. A heat source or flame is provided in a lower region of the incinerator and it is loaded with offal through an opening near the top. As the offal burns it settles downwards creating space for more offal to be added. However, this arrangement creates a lot of smoke and odour. Also because of the height of opening through which the offal is loaded carcasses have to be cut up in order to be lifted up and put into the incinerator. This can be inconvenient if large numbers of carcasses need to be disposed of.

According to a first aspect the invention consists in offal incinerator comprising a body, a chimney connected to the body at one end and provided with vent means at an other end, and means for burning offal placed in the body, the incinerator being so constructed and arranged that substantially no smoke particles escape from the vent means when the incinerator is being operated at its normal operating temperature.

It is envisaged that an incinerator in accordance with the invention may release some smoke and/or water vapour whilst it is warming up but that substantially no visible emissions will occur in normal operation at running temperatures. It will also be appreciated that the addition of a large amount of wet offal may temporarily cause some water vapour to be vented.

An advantage of such an incinerator is that it can be installed and used in an establishment without causing offense to people living adjacent to the establishment.

In a preferred embodiment the incinerator may be longitudinally arranged and comprise a longitudinally extending body, with burning means located at one end of the body and the chimney located at the same end of the incinerator.

The body may have a polygonal transverse cross section, preferably that of a generally regular polygon, and most preferably that of a hexagon.

Preferably the body is at least partially lined with a refractory material, to reduce heat radiated from the body.

Advantageously the body is lined at least partially with refractory bricks. Those may be loosely arranged in the body. Substantially the lower half of the body is preferably lined with refractory material, such as bricks. The upper half of the body may also be lined and may be lined with an insulating material such as ceramic fibre wool. The insulating material may be fixed to the upper half of the body or it may be held in place by any suitable means, for example heat resistant stainless steel cladding.

An advantage of loosely arranged bricks is that expansion and contraction of a metal body with temperature does not crack or otherwise destroy the lining.

Alternatively the body may be substantially fully lined with refractory material. A full refractory lining may provide greater retention of heat within the body and improve efficiency of the incinerator.

In use offal may be placed in the body of the incinerator and the burning means may be operative to burn the offal. Offal placed adjacent the burning means burns first, offal placed further away from the burning means being burnt more slowly. Hot air may circulate within the body before passing up the chimney and out of the vent means.

Preferably the vent means allows the hot air to be vented into the atmosphere.

Advantageously heating means may be provided in the incinerator such that secondary burning of the hot air occurs before the hot air escapes through the vent means.

An advantage of facilitating secondary burning is that substantially all smoke particles carried in the hot air are burnt off.

In one embodiment heating means may be provided in the body.

Preferably the heating means may comprise a baffle located in the body between the burning means and an opening leading into the chimney. The baffle may deflect hot air and flames rising from the burning means away from the opening and along the body. The baffle may be heated in the process and may reach a very high temperature.

Advantageously the baffle may also act as a guide over which the hot air must pass to enter the opening into the chimney. In passing over the baffle the hot air may be subjected to secondary burning so removing smoke particles.

Preferably the baffle is dimensioned such that complete secondary burning occurs before the hot air passes through the opening into the chimney. The dimensions of the baffle may have to be adjusted depending on the rate of flow of hot air over the baffle and on the amount of smoke particles produced from the type of offal normally burnt. The rate of flow of air may be dependent on factors such as the size of the opening, the height of the chimney and the bore of the chimney.

In one embodiment the baffle may be adapted to be supported on first and second depending supporting means, the supporting means and the baffle defining an enclosed passage through which hot air has to pass before reaching the opening into the chimney.

The supporting means may also have other functions.

Preferably the baffle may be made of stainless steel.

In another embodiment the baffle may comprise a tunnel, or box-like member, defining a pathway for air. The tunnel may comprise a separate element which is secured to the body, preferably inside the body.

Alternative heating means may be used to provide secondary burning. For example secondary heating means could be provided in the chimney itself.

Preferably the secondary heating means comprises one or more inwardly projecting members fixed to the inner surface of the chimney. The secondary heating means may be located in the lower section of the chimney. Preferably there are at least two inwardly projecting members and inwardly projecting ends of the members are joined to one another within the chimney.

The members may divide the chimney into axially extending sections.

Advantageously the burning means comprises an oil or gas burner which may produce a flame to burn offal contained in the body.

The burning means may be mounted such that the direction of the flame may be adjusted vertically and/or angularly.

Mounting means may comprise a plate having angular adjusting means. The plate may also be vertically slidable.

A fan adapted to blow air and/or oxygen into the incinerator may be provided to maintain conditions suitable for combustion of the offal.

In a preferred form a fan may be adapted to continue to blow air and/or oxygen into the incinerator after the flame has been switched off. By maintaining a supply of air and/or oxygen into the incinerator the offal may continue to burn long after the flame burning has ceased simply because of the temperature reached, provided there is sufficient oxygen available.

This may be particularly advantageous in that it may reduce the consumption of oil/gas since the flame is not essential to maintain combustion.

The burner may be modified such that it incorporates a fan which can continue to operate for a number of hours after the flame has been switched off so maintaining combustion conditions in the body of the incinerator. Combustion may continue even after the fan has been switched off if a sufficient amount of air can enter the body through the chimney and through the non-operating fan.

Preferably the chimney may be arranged to facilitate the draw of hot air and dispersal thereof.

The height of the chimney and bore thereof may be varied to provide an adequate draw and to ensure that the hot air is vented at a sufficiently high level relative to surrounding buildings to reduce odours collecting in the vicinity of the incinerator.

Advantageously a closable aperture may be provided mid-way along the body.

Preferably the aperture may be positioned and dimensioned such that whole carcasses may be readily introduced into the body through the aperture.

The aperture may be provided with a removable closure. In one embodiment this may comprise a lid hinged to the body.

According to a second aspect the invention consists in an offal incinerator comprising a longitudinally extending body having at least a partial lining of a refractory material, burning means adapted to burn offal placed in the body located at one end of the body, a chimney connected to an opening in the body located adjacent the same end, and secondary heating means adapted to provide secondary burning of smoke particles.

According to a third aspect the invention consists in an offal incinerator adapted to heat a supply of fluid, the incinerator comprising a body, burning means adapted to burn offal placed in the body, a chimney connected to the body and a fluid container arranged so that when the incinerator is in use heat is transmitted from the incinerator to fluid in the container.

An incinerator adapted to heat a supply of fluid, preferably water, may be advantageous in a number of ways. Heated water may be piped to a desired point to provide a hot water supply for example in adjacent buildings. Alternatively the heated water may be used in a heating system and may be circulated around a closed circuit supplying radiators. Alternatively the heated water may be used to supply both hot water and a heating system.

Heat transmitting means may be provided adapted to transmit heat radiated from the body of the incinerator. Alternatively the heat transmitting means may be adapted to transmit heat from the interior of the incinerator.

Preferably the heat transmitting means may be adjusted to vary the amount of heat transmitted depending on the temperature attained by the incinerator and the demand for hot water.

In one embodiment the fluid container comprises a tank provided with an inlet and an outlet, the tank being heated by a radiative external surface of the body.

Preferably the tank may be adjustably mounted on the body such that in a first position an inner face of the tank abuts the external surface of the body. The tank may be infinitely adjusted between the first position and a second position in which the inner face is separated by a gap sufficiently large that negligible heating of the fluid in the tank occurs.

In one embodiment the tank may be hinged to the tank along a longitudinal side of the tank. An adjusting means may be provided on a second longitudinal side in order to vary the gap.

Embodiments of the invention will now be described by way of example only with reference to the accompanying drawings in which: Figure 1 is a schematic side view of an incinerator in accordance with the invention; Figure 2 is a transverse cross-section along the line B-B in Figure 1, Figure 3 is a longitudinal cross-section of the incinerator shown in Figure 2 along the line A-A; Figures 4 and 5 respectively show a transverse and longitudinal cross section of an alternative incinerator; and Figure 6 is a transverse cross-section of the chimney shown in Figure 3 along the line c-c.

As can be seen in Figure 3 the incinerator of the first embodiment comprises a body 1, a burning means, generally indicated at 2, and a chimney 3. The body 1 comprises a longitudinally extending barrel 4 and end support portions 5 and 6. The barrel 4 has an upper planar surface 7 from which the chimney extends and inclined side surfaces 8,9 on either side. Curved side surfaces 10 connect the inclined side surfaces to a rounded base 11. The barrel 4 is formed from a unitary piece of 10mum mild steel plate shaped to the desired form. The end support portions are also made of mild steel plate. The gauge of steel used can be varied depending on the desired strength.

The body has a lining 12 of loosely packed firebricks 13. The lining 12 covers the base 11 and extends up the curved side surfaces 10 substantially as far as the inclined side surfaces 8,9. The lining 12 also extends up each end support portion 5,6. The lining assists retention of heat within the incinerator, increasing the efficiency and reducing heat out-put from the incinerator. As the firebricks are loosely stacked and are not bound together expansion and contraction of the mild steel barrel and end portions does not damage the lining. The body may be fully lined with firebricks 13 covering the upper planar surface 7 and the inclined side surfaces 8, 9 in addition to the base 11, curved side surfaces 10 and end supporting portions 5,6.

An aperture 14, through which offal 15 can be loaded into the body, is located substantially mid-way along the barrel 4. The aperture has substantially parallel fore and rear edges 16,17 respectively, which each extend from a longitudinal line 18 extending substantially mid-way across the upper planar surface transversely across the planar surface 7 and a substantial distance down one inclined surface 8. An upper edge 19 of the aperture extends substantially along the longitudinal line 18. A lower edge 20 extends substantially along an intersection 21 between the inclined surface 8 and the curved surface 10.

A lid 22 adapted to removably close the aperture is hinged at 23 to the upper planar surface 7 adjacent the longitudinal mid-line 18. The lid comprises an upper portion 24 and a lower inclined portion 25. The lid is dimensioned so that the upper and lower portions overlie a periphery of the aperture 14 sealing the body of the incinerator. The lid is provided with a handle 26 by which the lid may be moved between an open and a closed position. The handle 26 is thermally insulated from the lid. The aperture 14, is dimensioned so that carcasses of calves, pigs and sheep may be readily inserted into the body 1 of the incinerator without it being necessary to reduce the carcass into smaller portions. Should it be desired regularly to incinerate larger carcasses the aperture may be made larger without affecting the performance of the incinerator.

One end support portion 5 adjacent the chimney has a vertically orientated rectangular slot 27 and a corresponding opening 28 is provided in the firebrick lining. An adjustable cover plate 29 is movably located over the slot or an exterior face 30 of the end support portion. The plate 29 can be slidably moved up and down relative to the slot and fixed in a desired position. The plate can also be moved angularly relative to the end support portion 5 by a screw adjuster 31 co-operating with a lower portion of the cover plate. The screw adjuster varies a gap between the lower portion of the cover plate and the end support portion, so varying the angle of the plate and of a nozzle 32 welded to the plate. The nozzle 32 projects through the slot 27 and corresponding opening 28 in the firebrick lining. An oil burner 33 is attached to the cover plate by bolts 34 welded to the plate.

The burner 33 incorporates a fan (schematically indicated at 35) which blows air through the passage and into the body so ensuring that there is an adequate supply of oxygen in the body for combustion of the offal to occur. The fan operates continuously while the burner is producing a flame. Once the flame is switched off the fan continues to operate for a number of hours, typically two hours.

While the flame is being produced the temperature in the incinerator is raised to about 800-10000C.

After burning for a number of hours the flame can be switched off and combustion of the offal continues provided a sufficient supply of oxygen is maintained by the fan blowing air into the body. Once the fan is switched off air continues to be drawn through the fan and also some fresh air may be drawn down the chimney so enabling further combustion to occur for a period of time.

Steel strengthening angles 36,37 extend longitudinally along the body. Each angle comprises a depending portion 38 welded to the upper planar surface along one edge and provided with a transversely extending flange 39 along a second edge. A first angle 36 extends along substantially the mid-line 18 of the body while a second angle 37 extends along a join between the upper planar surface and the inclined side surface, the flanges of each angle projecting towards each other. A baffle 40 extending from an interior face 41 of the end support position is supported between and welded to the flanges, defining a tunnel through which hot air must pass to enter a second opening 42 in the upper planar surface communicating with the chimney.A section of the flange of the first angle 36 remote from the chimney is cut away to facilitate positioning of the baffle on the flanges during construction of the incinerator.

The baffle 40 comprises a sheet of stainless steel and extends longitudinally into the body 1 from the interior face 41. A substantially horizontal portion 43 of the baffle is aligned between the opening 28 and the second opening 42. Hot air and smoke rising from the flame is deflected by the horizontal portion 43 away from the second opening 42 and along the body.

Rising hot air from the flames and burning offal heats the baffle to red heat. As the hot air and smoke passes over the red hot baffle secondary burning occurs destroying smoke particles. Dimensions of the baffle such as length and width are selected so that complete secondary burning occurs of smoke particles produced by the type of offal normally loaded. It has been found that the baffle may be dimensioned such that complete secondary burning occurs when skinned carcasses are burnt. However, if whole carcasses of say sheep are loaded the wool thereon may produce so much more smoke than usual that complete secondary burning does not occur. Complete secondary burning could be obtained by adjusting the dimensions of the baffle. These dimensions may vary depending upon a bore 43 and height of the chimney.The chimney comprises two sections of metal pipe 44,45 each section having a flange 46 at each end. A lower flange of a lower section 44 of pipe is bolted or welded to the upper planar surface. An upper flange is fixed to a lower flange of an upper section 45 whilst vent means 47 are secured to an upper flange of the upper section.

Secondary heating means are located within the chimney in the lower section 44. The secondary heating means comprises four planar stainless steel members 70.

The four members 70 are joined together at a common edge 71 to form an afterburner 72 which is cross-shaped in cross-section. The afterburner 72 is fixed into the lower section 44 by joining an outer edge 73 of each member to an inside face 74 of the lower section 44 of the chimney. The afterburner 72 divides the chimney into four axially extending ducts 75. When the incinerator is in use hot air rising up the chimney heats the afterburner 75 which glows to red heat. Smoke and hot air pass through the ducts 75 formed by two adjacent members 70 and part of the inside face 74 of the lower section 44. The heat emitted by the glowing afterburner 72 burns off smoke particles in the hot air. The secondary heating means provides further and substantially complete burning of the smoke to produce smoke free exhaust.Alternatively the baffle 40 may be omitted altogether, and secondary burning of the smoke particles may be performed wholly by the secondary heating means.

In this embodiment the bore b of the chimney is 8"(20cm) and the chimney is 15'(5m) high and the baffle is 12"(30cm) wide and 30"(75cm) long. The body 1 is approximately 5' (1.6m)long, 4' (1.3m) wide and the upper planar surface is about 4'(1.3m) above the ground. A clearance of about 2"(5cm) exists below the base 11.

It has been found that in operation the incinerator described can dispose of approximately 3 tons of offal in about 25 hours. This does not represent continuous use but rather use spread over a week with incineration being carried out on about three, alternate, days of the week. On each day the incinerator has the flame operating for 5 to 6 hours and the fan operating for a further 2 hours. Clearly the potential capacity is much greater and would require only continuous use rather than a larger size incinerator.

Ash may be removed from the incinerator on a weekly basis or at more frequent intervals if a greater tonnage of offal is being incinerated.

The ideal length of the body is controlled by the power of the burner since if the body is too long offal furthest away from the flame does not fully heat up and burn completely. If a larger capacity incinerator is desired the capacity may be increased increasing the size of the body circumferentially rather than longitudinally.

As can be seen in Figures 1 and 2 a tank 48 is mounted on the inclined side surface 9, opposite the aperture. The tank is mounted on hinges 49 along a first longitudinal side 50. A screw adjuster 51 is centrally located along a second longitudinal side 52 and is adapted to vary a gap g between an inner face 53 of the tank and a radiative external surface of the body comprising the inclined side surface 9. In a first position the inner face abuts the inclined side surface 9 and heat is relatively efficiently transferred from the incinerator to fluid in the tank.

Adjusting the screw adjuster infinitely varies the gap moving the inner face towards or away from the inclined side surface. In a second position the gap g is sufficiently large for only a negligible amount of heat to be transferred from the external surface to fluid in the tank.

The tank is located on the inclined side surface 9 adjacent the chimney and the burner, this being a particularly hot region of the surface.

The tank is also provided with an inlet 54 and an outlet 55. Water enters the tank through the inlet 54 is heated and exists through the outlet 55. Hot water from the tank can be used simply to supply a hot water tap or may be used in a heating system. In the latter case, a closed circuit with suitable conventional circulating pumps is required.

Alternative means of varying the amount of heat transferred to the tank can be envisaged.

Figures 4 and 5 schematically show an incinerator which is similar to that of Figures 1 to 3, apart from the differences which are described below.

The incinerator has a hexagonal body 1'. This makes it easier and cheaper to make than if it had a curved body. Moreover, we were surprised to find that it was also possible to make successive incinerators to closer tolerances so that the shape of the incinerator was more reproducable. We were also surprised by that fact that having a substantially exactly reproducable incinerator body meant that we could better predict and control the operation of the manufactured incinerators - there was less variation in performance between hexagonal incinerators than cylindrical ones.

The multi-facetal body 1' could be made from a separate sheets secured together at their edges, or a sheet could be bent to form two or more facets of the body. A single sheet may be bent to form the body.

The lower half of the body 1' is lined with refractory bricks 13'. The upper half of the body 1' is lined with an insulating fibre 60 such as a ceramic fibre wool. The fibre 60 may be prone to damage. In order to prevent contact with carcasses from damaging the fibre 60 or to prevent it from picking up ash and other combustion products, stainless steel sheets 61 may be provided to cover it. The sheets 61 may also serve to hold the fibre 60 in place.

The baffle means of the incinerator comprises a four sided box-section tunnel 62 having an inlet 63 for air, an outlet 64 opening to a chimney 3', and a closed end 65. The tunnel is a separate component secured (for example bolted) to the inside of the body 1'. The tunnel is about 12 inches wide, 6 inches deep and extends for about 30 inches.

A water heater 66 is provided inside of the body 1', instead of outside of it, and has inlet and outlet pipes 67 passing through an end wall of the body. The water boiler is about 12 inches long, 7 inches deep and 5 inches wide.

A rough guide to the size of the incinerator is that the body is about 3 feet tall, 5 feet long, 4 feet wide, has a door about 32 inches long and 14 inches on its sloping facet and 12 inches on the upper facet (as seen in Figure 4), and the chimney has a seven foot height.

Claims (23)

1. An offal incinerator comprising a body, a chimney connected to the body at one end and provided with vent means at another end, and burning means for burning offal placed in the body, the incinerator being so constructed and arranged that substantially no smoke particles escape from the vent means when the incinerator is being operated at its normal operating temperature.

2. An incinerator according to claim 1 in which the body is at least partially lined with a refractory material, to reduce heat radiated from the body.

3. An incinerator according to claim 1 in which the body is substantially fully lined with refractory material.

4. An incinerator according to any preceding claim in which the upper half of the body is lined with insulating material.

5. An incinerator according to any preceding claim in which hot air circulates within the body before passing up the chimney and out of the vent means.

6 An incinerator according to claim 5 in which heating means are provided in the incinerator such that secondary burning of the hot air occurs before the hot air escapes through the vent means.

7. An incinerator according to claim 6 in which the heating means comprises a baffle located in the body between the burning means and an opening leading into the chimney.

8. An incinerator according to claim 7 in which the baffle is heated as it deflects hot air and flames.

9. An incinerator according to claim 7 or claim 8 in which the baffle acts as a guide over which the hot air must pass to enter the opening into the chimney.

10. An incinerator according to any one of claims 7 to 9 in which the baffle is dimensioned such that complete secondary burning of the hot air occurs before the hot air passes through the opening into the chimney.

11. An incinerator according to any one of claims 7 to 10 in which the baffle is adapted to be supported on first and second depending supporting means, the supporting means and the baffle defining an enclosed passage through which hot air has to pass before reaching the opening into the chimney.

12. An incinerator according to any preceding claim in which secondary heating means are provided in the chimney to provide secondary burning of the hot air.

13. An incinerator according to any preceding claim in which the burning means is mounted such that the direction of the flame may be adjusted vertically and/or angularly.

14. An incinerator according to any preceding claim in which a fan adapted to blow air and/or oxygen into the incinerator is provided to maintain conditions suitable for combustion of the offal.

15. An incinerator according to claim 14 in which the fan is adapted to continue to blow air and/or oxygen into the incinerator after the flame has been switched off so maintaining combustion conditions in the body of the incinerator.

16. An incinerator according to any preceding claim in which a closable aperture is provided mid-way along the body.

17. An incinerator according to claim 16 in which the aperture is positioned and dimensioned such that whole carcasses may be readily introduced into the body through the aperture.

18. An offal incinerator adapted to heat a supply of fluid, the incinerator comprising a body, burning means adapted to burn offal placed in the body, a chimney connected to the body and a fluid container arranged so that when the incinerator is in use heat is transmitted from the incinerator to fluid in the container.

19. An incinerator according to claim 18 in which heat transmitting means is provided adapted to transmit heat radiated from the body of the incinerator.

20. An incinerator according to claim 19 in which the heat transmitting means is adapted to transmit heat from the interior of the incinerator.

21. An incinerator according to claim 19 or claim 20 in which the heat transmitting means is adjustable to vary the amount of heat transmitted depending on the temperature attained by the incinerator and the demand for hot fluid.

22. An incinerator substantially as described and illustrated herein with reference to Figures 1, 2, 3 and 6 of the accompanying drawings.

23. An alternative incinerator substantially as described and illustrated herein with reference to Figures 4 and 5 of the accompanying drawings.