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The Beaman & Deas Destructor has also recently come into prominence from the large amount of refuse destroyed per cell. The same remarks however apply to this as to the Meldrum above referred to, it being nearly always used for high steaming. In both these cases auxiliary coal firing takes place at the same time as the refuse is being destroyed, and it is well known amongst Municipal Engineers that the results achieved by cells under such circumstances have to be received with a considerable amount of caution.
Next to the Fryer, the Horsfall Cell appears to be in most general use. It has been introduced much more recently than the Fryer and is similar to the latter in that it allows of an economical design of Building, and also like this cell its primary object is to destroy the refuse, steaming being an after consideration. It has not therefore been used to any great extent in connection with Electric Light or Power Stations, although a considerable amount of power is utilized in nearly every case where it has been installed.
At the Powderhall Destructor Works, Edinburgh, it was proved in an action that noxious gases and dust from the existing cells (the Fryer) were emitted in such quantities as to cause a considerable nuisance and upon expert advice the Horsfall Co. were called in to substitute the Horsfall for the Fryer Cells, the ground for complaint being subsequently proved to have been removed by this alteration.
At Bradford, Huddersfield and Blackpool also the Fryer Cells were replaced by the Hors- fall, some of the largest installations of the latter being at Bradford, Brussels, Edinburgh, Hamburg, (the largest Destructor in the world consisting of 36 cells), Hull, Leeds, Sheffield, aud Fulham.
The Warner "Perfectus" Destructor, made by Messrs. GODDARD, MASSEY & WARNER of Nottingham, is somewhat similar to the Fryer in general arrangement. It has achieved a fair success but has not been adopted to the same extent as others previously mentioned. It is now in use at Hornsey, Sheffield, Bournemouth, Madras, Sydney and several sınaller places.
The Heenan & Froude Twin Cell has also been adopted to some extent, over 100 cells of this type having been erected within the past few years. The makers claim an average of over 10 tons per cell destroyed per day. It is to be found in use at Gloucester, Barrow- in-Furness, Northampton, Wakefield, &c.
In addition to the cells above referred to there are numerous others on the market that have been adopted to some slight extent; such as the Willoughby, the Mason, the Stirling, the Garlick and Christenson in India, and there are still other makes in use in America.
Speaking generally there is a great sameness in the results when examined in detail, and each type appears to have accomplished at one place or another quite as successful results as its competitor somewhere else.
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As a matter of fact town refuse varies to a great extent not only between one town and another but between different districts and between different days in the same town. case which came under my personal observation the refuse from two districts of a city could not be burnt by itself. It had to be either mixed with fuel or with the refuse from other districts which was of a much higher calorific value.
It is important however that a Destructor should be first designed to destroy refuse and to do this thoroughly; in fact to ensure that no unburnt refuse should escape among the clinker and no dust should leave the chimney top or cake around it.
Adopting this view, the cells for high steaming power, such as the Meldrum and the Beaman & Deas, may be discarded but it might be considered desirable to invite tenders from the following makers of cells, in addition to the Horsfall Co., under certain conditions and modifications: the Fryer (MANLOVE & ALLIOTT), the Warner Perfectus (GODDARD, MASSEY & WARNER), and the Heenan Twin Cell (Messrs. HEENAN & FROUDE).
The Horsfall type has achieved uniformly good average results and is a thoroughly up- to-date cell, its design being an exceedingly good one. It is claimed that the use of steam jets to produce forced draught has an advantage over simple forced draught in that it produces water gas in passing through the incandescent fuel which materially aids combustion. This is however doubtful in the case of refuse which already contains a considerable amount of moisture to be driven off before burning, as it can hardly be improved by injecting air saturated with moisture. I would therefore suggest that whatever type of cell may be