GB2180630A - Cremators - Google Patents

Abstract

A cremator 10 comprising primary and secondary combustion chambers 12,13 each provided with a respective burner 21,22 and air jets 16,20 is constructed so as to be operated under positive pressure for any desired period of time without leakage therefrom of combustion products. In the preferred embodiment, to provide for the airtight seal of the combustion chambers 12,13 and all other flueways the cremator 10 is lined internally with high quality refractory brick 36, which is covered with an insulating layer (37, Figures 2,3) which in turn is encased in fully welded steel cladding (38). The top of the combustion chamber 12 has mild steel top plates 40 over a stack bonded ceramic fibre roof 41 and at the bottom of the secondary combustion chamber 13 there is a fully welded mild steel base plate 39. The charge door 23 is provided with a strip (47, Figure 4) which is resiliently deformable, when the door is closed, by a rigid flange (45) on the chamber 12. <IMAGE>

Description

SPECIFICATION Cremators This invention concerns cremators.

It concerns more particularly the improvement of cremators ofthetype comprising a combustion chamber for receiving a coffin for burning, burner means projecting into the combustion chamber, the combustion chamber having a primary combustion chamber and below this a secondary combustion chamber, and air jets for supplying air both to the primary and the secondary chambers of the combustion chamber.

The latter type of cremator normally operates underwhatone mightterm a 'negative pressure wherein a draught is created by control of the opening and closing of a damper in a flue connecting with the combustion chamber and possibly having a chimney stack and perhaps also a venturi between the flue and the combustion chamber, so as to ensure suction on and thereby an outflow of the products of combustion, such as waste gasses, from the combustion chamber. In fact air would tend to be drawn into the combustion chamber of the cremator from the surrounding atmosphere through any potential leakage passages.This is particularly importantfrom the point of view of not allowing the build up of combustion products in the combustion chamberto the extentthatthey begin to leakfromthe combustion chamber, and the cremator itself, to atmosphere thereby possibly creating great distress to crematoria visitors not to mention a health hazard to cremator operators. The suction on the combustion chamber must be high enough to guard against leakage.

The disadvantages with this type of cremator are that the air pressure in the combustion chamber has to beverycarefully monitored and controlled, and hence so does the supply ofairto the combustion chamberand possiblyalsothe bottom airchamber, and to create sufficient through draught, the flue and any associated chimney, has to be fairly high.

It is an object of the present invention to provide a cremator in which the aforementioned disadvantages are wholly or substantially wholly obviated.

With this object in view the present invention provides a cremator substantially of the type as aforementioned and in which its combustion chamber can be used and maintained in use for any desired period of time under a positive pressure without leakage therefrom of products of combustion.

The term positive pressure as used herein before is to be taken to mean thatwhen the cremator is being operated, with its combustion chamber charged with a coffin which is being burnt, the suction on the combustion chamber need only be minimal to ensure a well regulated outflow of the products of combustion therefrom so thatthere may be pressure on the in teriorsurfacesofthecombustion chamber.

The invention will be described further, by way of example, with reference to the accompanying drawingsinwhich:- Figure lisa sectionai elevation of a preferred embodiment of the cremator of the present invention; Figure2 is a cross-section on the line A-A of Figure 1.

Figure3 is a cross-section on the line B-B of Figure 1;and Figure 4 is a detailed part cross-sectional view of a door sealing arrangement of the cremator of Figures 1 to3.

Referring to Figures 1 to 3, the preferred embodi ment of the cremator is denoted generally therein by the reference numeral 10.

The cremator 10 comprises a primary combustion chamber 12 for receiving a coffin 11 for burning and below chamber 12 is a secondary combustion chamber 13, on either side of which chamber 13 lie tertiary combustion zones 14. Below the chamber 13 and the zones 14 are respective fly ash clean out doors 15.

The primary combustion chamber 12 has roof air jets 16 (only one of which is shown for supplying air to the primary combustion chamber 12. Hearth 17 for the coffin 11 also has ai r jets 27 (Figu re 3)for su pply- ing airto the chamber 12. The hearth 17 has a bridge wall 32 serving as an end stop forthe coffin 11.

The secondary combustion chamber 13 is supplied with air by means ofairsupplyfan 18 and duct 19 (both shown in outline only) through openings 20 in the end wall ofthecremator 10.

There is a medium or high velocity burner 21 for the primary combustion chamber 12 and a sec ondary burner 22 for the secondary combustion chamber 13. The burner 21 and the burner 22 are both situated in the end wall of the cremator 10opposite charge door 23, and one above the other.

Between the primary and secondary combustion chamber 12 and 13 there is an interconnecting flue 24. Awaste gas port 25 from the chamber 12 atthe top of the flue 24 and a refractory bullseye 26 atthe bottom of the flue 24 ensures intimate contact be- tween secondary air, combustion products for the primarycombustionchamber 12andsecondary burner gases.

At the same end of the cremator as the flue 24 are vertical flueways 28 (Figure 2), one on each side of the flue 24.

Two spaced-apart dividing walls 29,30 define between them the secondary combustion chamber 13 and serve also to separate it from the respectivetertiary combustion zones 14. One corresponding end of each wall 29,30 is provided with chequerwork openings 31 providing flueways for gasses passing be tween the secondarycombustion chamber 13 and the tertiary combustion zones 14.

Below the primary combustion chamber 12 a small distance beyond the charge door 23 is a sump 33 into which fully cremated remains can be raked for collection in a receptacle 34 belowthe sump 33. The cremated remains sump33 has a sealing cover35.

Since the cremator 10 of the present invention is intended to be operated under positive pressure without leakage of e.g. smoke into the surrounding atmosphere, measures have been taken to ensure good airtight seal of the combustion chambers 12, 13.

The measures taken are briefly asfollows:-the primary and secondary combustion chambers 12, 13 are lined internally with a high quaiity refractory brick 36; the refractory brick 36 is covered externally with a low conductivity insulation layer 37; overthe layer 37 is steel casing clad 38, shown in dot-dash outline in Figures 2 and 3,which is fully welded mild steel plate to provide an airtight seal; a mild steel base plate 39 fully welded; mild steel top plates 40; underneath the top plates 40 a stack bonded ceramic fibre roof 41 forthe primary combustion chamber 12; and a ceramicfibre lined waste gas flue collection box 42 and flue 43.

Afurthermeasureistheairtightsealing of the cremator's charge door 23 with the open end ofthe primary combustion chamber 12. To fulfill this measure a sealing arrangement is provided said sealing arrangement being shown in Figure4 and being thus; around the edges 44 of the open end of the primary combustion chamber 12 is a continuous rigid flange or strip 45 projecting outwardly in the direction of the charge door 23. On the inside surface 46 ofthe charge door 23, around the edges of said door, is a continuous resiliently deformable strip 47.When the door 23 is closed it is locked against the open end of the primary combustion chamber 12 by means of respective levers 48 (one each side of the door 23) and its associated linkage 49 such that the rigid flange or strip 45 is forced into the deformable strip 47. resiliently deforming the same and providing a good airtight seal.

With this provision of the latter said sealing arran gement and further good sealing ofthe combustion chambers 12, 13 the cremator can be operated under positive pressure as aforesaid without any leakage of e.g. smoke into the surrounding atmosphere.

The operation ofthe cremator under positive pressure provides for a more intense cremation with savings in fuel consumption and cremation time. Furthe rmore,the degreeto which the combustion process has to be monitored by an operative is a lot less than with conventional cremators.

In addition, as the cremator of the present inven- tion does not have to ensure that there is a high suction on the combustion chambers 12, 13 by the crea tion of athrough draught,theflue 43 can be made much shorter and without any need for the connection of a stack thereto.

Conventional cremators are designed and intended to be operated with their combustion chamber substantially under continuous negative pressure.

The cremator of the present invention is designed to operate with its combustion chambersubstantially under positive pressure.

Claims (4)

1. A cremator comprising a primary combustion chamber for receiving a coffin for burning, having a burner protruding to said chamber, and disposed below the primary combustion chamber a secondary combustion chamber, also fitted with a burner, and airjets for supplying air both to the primary and sec ondarychambers of the crematorcharacterised in that the crematorcan be used and maintained in use for any desired period oftime under a positive pressure without leakage therefrom of products of combustion.

2. A cremator as claimed in claim 1 wherein to achieve an airtight seal the primary and secondary combustion chambers are lined internally with a high quality refractory brick; the refractory brick is covered externally with a low conductivity insulation layer; overthe layer is a steel casing clad; there is a mild steel base plate; there are mild steel top plates; the top and the base plates are fully welded to side plates and to the steel cladding to prevent leakage; underneath the top plates a stack bonded ceramic fibre roofforthe primary combustion chamber; and a ceramic fibre lined waste gas flue collection box and flue.

3. A cremator as claimed in claim 2 wherein the cremator charge door is provided with a sealing arrangement comprising a continuous rigid flange arranged around the edges ofthe open end. of the primary combustion chamber and projecting outwardly in the direction of the charge door, and on the inside surface of the charge door, around the edges of the door, is a continuous resiliently deforrnable strip suchthatthe rigid flange orstrip isforced into the deformable strip resiliently deforming the same and providing an airtight seal, when the charge door is closed.

4. A cremator substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.