The present invention relates to a furnace and especially but not exclusively to an electric furnace for the burning or cremation of bodies and or body parts .

Traditionally, furnaces have been gas fired and are typically arranged so that the fuel, in the form of gas, is burnt to provide a working temperature and gas is continuously supplied throughout the combustion procedure.

This known type of furnace is not responsive to the charge being burnt and may therefore be inefficient as well as producing an unnecessarily large quantity of waste gases, some of which may be pollutants, which may be released into the atmosphere.

According to the present invention there is provided a furnace for the incineration of human remains, comprising:

a first chamber adapted to receive a body to be incinerated;

a gas outlet for providing a gas that will support combustion to said first chamber;

gas discharge means for allowing the egress of gas resulting from the incineration of a body from said first chamber;

first chamber heating means for raising the temperature in said first chamber;

a second chamber adapted for the combustion of gas resulting from the incineration of a body;

a first gas inlet, connected to said gas discharge means, for allowing the ingress of gas resulting from the combustion of a body into said second chamber;

a second gas inlet for providing a gas that will support combustion to said second chamber;

second chamber heating means for raising the temperature of gas in said second chamber; and

exhaust means for allowing the egress of gas from said second chamber.

Preferably, there is provided gas transfer means for providing a pressure differential in said furnace so as to cause the flow of gas from said first chamber through said second chamber to said exhaust means.

Preferably, there is provided control means to allow the rate of flow of gas via said gas outlet, said first gas inlet and/or caused by said gas transfer means to be selectively adjusted.

Preferably, there are provided sensors in said first and/or second chambers, said sensors being adapted to sense one or more operating parameters of said first and/or second chambers .

Preferably, said sensors are adapted to provide data relating to said operating parameters to a computer.

Preferably, there is provided a computer adapted to operate said control means in accordance with predetermined instructions and in response to data received from said sensors.

Preferably, said gas transfer means includes a fan adapted to force gas through said exhaust means.

Preferably, there is provided gas mixing means in said second chamber, said gas mixing means being adapted to mix gas resulting from the combustion of a body with gas supporting combustion.

Preferably, said gas mixing means is provided by the configuration of at least part of said second chamber providing a tortuous passage.

Preferably, said gas outlet is provided in the first chamber and is in the form of at least one member upon which the body to be incinerated may rest, said member being provided with at least one aperture at least part of which is, in use, in contact with said body.

Preferably, said first chamber is adapted to receive a small body, wherein said first chamber is adapted to retain a substantial proportion of the cremated remains of said small body, and wherein said retained remains may be subsequently collected.

Preferably, said. furnace is portable.

The present invention also provides a method of operating a furnace.

Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings in which:

Fig. 1 is a schematic vertical cross-sectional view along the length of an embodiment of a furnace in accordance with the present invention;

Fig. 2 is a schematic vertical cross-sectional view across the width of the furnace illustrated in Fig. 1;

Fig. 3a is a side view of a first support bar suitable for use in the embodiment of Figs. 1 and 2;

Fig. 3b is a vertical cross-sectional view of the support bar of Fig. 3a;

Fig. 3c is a side view of a second support bar suitable for use in the embodiment of Figs. 1 and 2;

Fig. 3d is a vertical cross-sectional view of the support bar of Fig. 3c;

Fig. 4 is a schematic cross-sectional view of an alternative embodiment of a furnace in accordance with the present invention; and

Fig. 5 is a schematic cross-sectional view of the furnace illustrated in Fig. 4.

Referring to Figs. 1 and 2 a furnace, suitable for the

cremation of cadavers, comprises a first chamber 5, for accommodating a body such as cadaver to be cremated, and a second chamber 3A, 10A being tortuous in construction and having a first end 3 connected to the first chamber 5 and a second end 10 being adjacent to a flue 7 for expulsion of gases from the furnace. The second chamber is adapted for the burning of the products of the combustion of a body burnt in the first chamber 5.

The first chamber 5 houses a pair of beams 6 upon which a cadaver may be supported. The beams 6 are shown in detail in Figs. 3a, 3b, 3c and 3d and will be described with reference thereto in due course. The first chamber 5 and the first end of the second chamber 3 are connected by a gas outlet 12 from the first chamber connected to a gas inlet 8 in the second chamber allowing the passage of gases from the first chamber 5 to the first end 3 of the second chamber. The second chamber comprises a first portion 3A which runs the length of the first chamber 5 adjacent to and beside the first chamber 5 and separated therefrom by a dividing wall 20. The second chamber also comprises a second portion 10A located above the first chamber 5 and larger in size than said first chamber. The tortuous configuration of the second chamber 3A, 10A is provided by first, second and third baffle plates 4A, 4B, 4C provided in the first portion 3A of the second chamber. A second chamber heating element 2 is provided in the second portion of the second chamber. At the first end 3 of the second chamber adjacent the position of the second chamber gas inlet 8 there is provided a second chamber air inlet 9 through which air from outside the chamber may be brought into the first end of the second chamber 3. The flow of air through the air inlet 9 is controllable by the operation of one

or more flaps 9A, provided therein. The baffle plates 4A, 4B, 4C enhance the mixing of air introduced into the first portion of the second chamber 3A via the air inlet 9 and gases brought into the second chamber 3A, 10A from the first chamber 5 via the second chamber gas inlet 8 and thus enhance the burning of the waste gases from the first chamber 5 in the second portion 10A of the second chamber.

A pressure sensor 11 is provided in the first chamber 5 in order that the pressure in the first chamber 5 can be monitored. Temperature sensors (not shown) are also provided in the first chamber 5 and in the first portion 3A and second portion 10A of the second chamber. The first chamber 5 and second chamber 3A, 10A are, together, housed and defined by walls made from a thermally insulating heat resistant material 1.

Figs. 3a, 3b, 3c and 3d illustrate the construction of the beams located in the first chamber 5 upon which the cadaver or other body to be cremated may be laid. The beams 6 are made from silicon carbide and are provided with air outlets 13 through which air may be fed into the first chamber 5. The beams 6 are both substantially square in cross-section each having substantially vertical side walls 16 and substantially horizontal top walls 21. Each of the beams 6 is provided with a first set of air outlets 14 located in the side walls 16 of the beam and each beam 6 is also provided with a second set of air outlets 15 located at an upper top corner 17 of the beam 6. The outlets 13 of the first set of air outlets 14 are regularly spaced along the side walls of the beams 6 and provide air to the cavity of the first chamber 5. The outlets 13 of the second set of outlets 15 are provided in order to allow air to enter the body resting upon the bars and

are not equidistantly spaced along the bars. Entry of air to the body considerably reduces the combustion time since it allows the combustion from the inside as well as from the outside of the body. As illustrated schematically in Figs . 3a and 3c the first four outlets, together designated by the reference numeral 18, of the second set of outlets 15 are disposed relatively close together and are positioned adjacent to where, in use, the head of a cadaver to be placed in the first chamber 5 will be positioned, since a high intensity of air is required for incineration of this part of the body. Further outlets are designed to be positioned further along the body and the spacing between them is determined according to the amount of air required for incineration of a given body part. For example, the last two outlets, together designated by the reference numeral 19, are most widely spaced and are positioned so as to be adjacent to the legs of the cadaver, which require a lower intensity of air for incineration.

In use, the rate of flow of air through the beams 6 into the first chamber 5, the rate of flow of combustion products from the first chamber 5 to the beginning of the second chamber 3 and the rate of flow of the combustion gases through the second chamber 3A, 10A as well as the temperature of the first and second combustion chambers 5, 3A, 10A are controlled by a computer operated control system. The use of such a computer operated control system in conjunction with the use of electric heating elements (not shown) in the first chamber 5 and an electric heating element 2 in the second portion 10A of the second chamber, enables much more accurately controlled combustion of the body to be cremated and of the combustion gases from that body than has in the past been allowed by gas operated

furnaces .

In use, once a body is placed in the first chamber 5 and the cremation process is begun, combustion gases from the combustion of the body are fed into the beginning of the second chamber 3 where they are introduced to air which is brought into the beginning of the second chamber 3 by the air inlet 9. The combustion gases and air are fed through the tortuous route of the first portion 3A of the second chamber passing the baffle plates 4A, 4B, 4C and during this passage the noxious combustion gases are mixed with the air. The mixture of waste gases and air then enters the second portion 10A of the second chamber where it is burnt before relatively clean exhaust is discharged from the furnace via the flue 7.

In use, the main chamber 5 is maintained at a predetermined pressure which is slightly lower than atmospheric pressure. This negative pressure is maintained by pressure control means in the form of an extractor fan 7A located in the flue 7 which serves to create a pressure differential through the tortuous route of the second chamber 3A, 10A. The operation of the fan 7A is controlled by the computerised control system, and hence control over the pressure in the whole system is obtained. The operation of the fan may be controlled by varying the speed of the fan or by providing adjustable flaps adjacent the fan 7A or the flue 7.

The negative pressure in the first chamber 5 is monitored by the pressure switch 11. The computerised control system controls the pressure by monitoring the pressure and adjusting the operation of the extractor fan 7A as required. The flap 9A of the air inlet 9 is

also operated by the control system in order to ensure that the mixture of air and combustion gases in the second chamber is of the correct proportions to enable substantially maximised combustion of undesirable products of the initial combustion of the body. A flap 9A (rather than say a fan) may be used for controlling the induction of air because of the negative pressure maintained in the furnace. The position of the flap 9A and the air inlet 9 is important, since it is vital to obtain good mixing of the air and combustion products. Clearly, the more air that is introduced through the air outlet 9, the more combustion products may be drawn from the main chamber and effectively burnt in the second chamber.

In use, the fan 7A is set maximum during the charging of the coffin or other products into the first chamber 5 and for a short preset time after the sealing of the furnace. At this point the air supply to the first chamber 5 (through the outlets 13 of the beams 6) and the supply of air to the first portion 3A of the second chamber (via the air inlet 9) are reduced to zero. This ensures maximum intake of air into the first chamber 5 of the furnace through the furnace door (not shown) . This minimises the escape of heat through the furnace door towards the operators charging the furnace and also prevents flashback. The fact that a large amount of air enters the furnace through the open furnace door also provides sufficient oxygen in the second chamber to burn the large quantity of noxious combustion products (in particular carbon monoxide) created by the combustion of the coffin and in particular the varnish thereon.

After the furnace door has been closed and the short preset time has expired the extractor fan 7A and flaps

9A are then adjusted by the control system to preset operating modes . The fan is set to control the pressure in the first chamber 5 (and the second chamber 3A, 10A) and the flap is set to control the input of air into the first portion 3A of the second chamber. By adjustment of the fan 7A and the flap 9A the combustion of the body in the first chamber and of the combustion products in the second chamber may be controlled throughout the process.

The rate of air flow into the first chamber via the beams 6 is also controlled by the control system and air is fed into the first chamber 5 through the beams 6 at a preset level, controlled by the control system. This preset level of air flow is maintained until a 20°C rise in temperature is measured at the beginning of the second chamber 3 or until a 2% drop in oxygen level is detected in the second chamber 3A, 10A. The air flow into chamber 1 is then stopped completely until 35 minutes have elapsed or until a drop in temperature of 30°C at the start of the second combustion chamber 3 is measured. At this point air is reintroduced into the first chamber 5 at a rate which increases in a predetermined manner, starting with a relatively small rate of flow and slowly increasing to a predetermined maximum rate of flow suitable for efficient combustion of the remains of the body.

The rate of flow of air into the first chamber 5 is also controlled in response to readings from the second chamber of the residence time of the combustion gases in said second chamber. It is necessary to control the flow of air into the first chamber 5 in response to this parameter because the greater the flow of air into the first chamber 5 the more combustion products will pass into and through the second chamber 3A, 10A. It

is, however, important that a given residence time of gases in the second chamber 3, 10 is maintained, in order to ensure satisfactory combustion of the gases. For example, the present requirement is for a residence time for the gases in the second chamber of at least two seconds.

In the present embodiment, therefore, if the residence time of the gases in the second combustion chamber is in danger of dropping below two seconds the control system will temporarily halt the rise in rate of flow of air into the first chamber 5 until such time as the sensor informs the computer that it is safe to continue. When the combustion operation is nearing completion and there is both a significant drop in temperature in the first chamber 5 and also the oxygen level in the first chamber 5 has reached a preset point, the rate of air flow into the first combustion chamber will be gradually reduced by the control system. This helps prevent unwanted passage of gas and corresponding heat loss from the furnace.

Before the body is put into the first chamber the temperature in the first chamber is raised by means of electric heating elements (not shown) in said first chamber. During the combustion process the use of the heating elements may be reduced by the control system and the body itself may be used to fuel continuing combustion and to maintain a suitable combustion temperature.

The use of the control system to maintain the desired temperatures and pressures in the first combustion chamber reduces combustion time and also reduces delays between combustion of one charge and the next. The furnace may therefore be in almost constant use. This

may lead to a build up of heat within the furnace, necessitating cooling of the equipment and this is achieved by increasing the flow of air through the first and second chambers . This increase in flow of air may be instigated by the control system in response to temperature readings from within the furnace rising above a given preset level.

In the embodiment of Figs. 1 and 2 the volume of the first chamber may be about 1.4 cubic metres and the temperature of the first chamber 5 upon charging of this chamber is about 500 - 550°C. Mid-process the temperature in the first chamber 5 may reach about 1000°C or more. The volume of the second chamber may be approximately 3.6 cubic metres and the temperature of the second chamber during burning of the combustion products is of a minimum of about 850°C. Between incineration cycles the flue 7 is isolated from the furnace by means of a shutter (not shown) in order to prevent unnecessary heat loss.

An alternative embodiment of the present invention is illustrated in Figs. 4 and 5. This illustrated embodiment is a smaller version of the furnace of Figs. 1 and 2 having a first chamber volume of approximately 0.3 cubic metres and a second chamber volume of approximately 0.7 cubic metres. The structure of the embodiment of Figs. 4 and 5 is similar to the structure of the embodiments of Figs. 1 and 2, although details of the shape and configuration differ. A brief description of the embodiment of Figs. 4 and 5 is therefore provided.

Referring to Figs . 4 and 5 an embodiment of a furnace comprises a first chamber 35, for accommodating a small body such as foetal remains, cadavers of stillborn

children and body parts which need to be disposed of as a result of surgery, to be cremated, and a second chamber 33, 40 being tortuous in construction and having a first end 33 connectable to the first chamber 35 and a second end 40 being adjacent to a flue 37 for expulsion of gases from the furnace. A fan (not shown) is provided in the flue 37 to create negative pressure in the furnace.

The first chamber 35 may house a pair of beams 36 upon which a cadaver may be supported. Illustrative embodiments of suitable beams 36 are shown in detail in Figs. 3a, 3b, 3c and 3d and have been described above. The first chamber 35 and the first end of the second chamber 33 are connected by a gas outlet 42, and a gas inlet 38 allowing the passage of gases from the first chamber 35 to the first end 33 of the second chamber. The second chamber comprises a first portion which runs the length of the first chamber 35 adjacent to and beside the first chamber 35 and separated therefrom by a dividing wall 45. The second chamber also comprises a second portion located above the first chamber 35. The tortuous configuration of the second chamber is provided by first, second and third baffle plates, 34A, 34B, 34C provided in the first portion of the second chamber. Three second chamber electric heating elements 32 are also provided adjacent the second chamber and three first chamber electric heating elements 43 are provided adjacent the first chamber. At the first end 33 of the second chamber, adjacent the position of the second chamber gas inlet 38, there is provided a second chamber air inlet 39, with a flap (not shown) provided therein through which air from outside the chamber may be brought into the first end of the second chamber.

A pressure sensor (not shown) is provided in the first chamber 35 in order that the pressure in the first chamber 35 can be monitored. Temperature sensors (not shown) are also provided in the second chamber. The first chamber and second chamber are, together, housed and defined by walls made from a thermally insulating heat resistant material 31.

The operation of the embodiment of Figs. 4 and 5 is similar to the operation of the embodiment of Figs. 1 and 2 and will therefore not be described in detail. A computerised control system may be an important part of the embodiment.

The embodiment of Figs . 4 and 5 is adapted for the combustion of small bodies such as foetal remains, cadavers of stillborn children and body parts which need to be disposed of as a result of surgery. It is, therefore, less important to supply air through the beams 36 directly into the body being cremated, although supply of air in this way would still expedite the combustion process. Such an embodiment could therefore be provided with air inlets 44 in the furnace well introducing air into the first chamber 35, in addition to, or as replacements of, the air inlets provided in the beams 36.

The embodiment of Figs. 4 and 5 may comprise a portable furnace or incinerator and is particularly suitable for the incineration or cremation of foetal remains, stillborn children and also body parts which may need to be disposed of as a result of surgery. A small furnace as described has considerable advantages over a larger furnace, including greater efficiency for the combustion of small charges and the possibility to ensure that the cremated remains of individual foetal

remains, stillborn children etc may be collected and returned to the family of the deceased. When conventionally sized furnaces are used for such purposes most of the cremated remains are lost due the scale of the cremation process.

The embodiments described above provide efficient clean and rapid furnaces. The supply of air directly into the body expedites the incineration procedure. Furthermore, the supply of relatively cool air, such as air directly from the atmosphere, via the beams 6, 36 prevents overheating of body tissues which is known to cause an imbalance in proteins allowing a shell to form and preventing efficient destruction of the tissue. Using air in this manner also creates vibrations which assist in breaking down tissue.

Modifications and improvements may be incorporated without departing from the scope of the invention, and elements described could be replaced by mechanical equivalents thereof.