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The boiler to be used :
(i) For heating water for use in the Slaughter Houses. (ii) For a Disinfecting Plant.
(iii) For driving an engine of 50-H. P.
In drawing up this Specification I had Kennedy Town in view as the locality of the Destructor. It may also be possible, after the erection of a suitable chamber, to use the heat for cremating human bodies; the question of building a Crematorium has already been broached and with a nominal expenditure the experiment might be tried in connection with the Refuse Destructor.
Of the foregoing proposals D (iii) is the only one needing further remarks.
The Horse Power to be obtained from a boiler heated from a Refuse Destructor will depend upon the heat generated in the cells and upon the position of the boiler so as to best utilize this heat. The calorific properties of Hongkong refuse being an unknown quantity, it is impossible to estimate the size of boiler that should be provided or, indeed, to say whether a boiler should be fixed at all; under these circumstances I recommend that no boiler be purchased in England in the first instance, one can be obtained locally for the purposes of experiment.
The 50-H. P. engine would also wait; but if the necessary heat can be obtained to raise steam to drive it, it might be used to drive a dynamo for the following purposes, viz.:-
(a) To light the Slaughter House and Destructor Works and, if desired, the Infections
Diseases Hospital.
(b) To pump water to the Peak by means of an electric motor, fixed at the Bonham Road
Pumping Station.
The above assumes that no monopoly has been granted to the Electric Light Company to supply electric power to Government buildings.
SITE.
The City extends for some four miles in length, and as all refuse has to be taken to the Destructor, the latter should be in as central a situation as possible and it should also be on the lower levels.
The value of ground in the central portion of the City on the lower levels is so great as to prohibit the erection of a Destructor there, and the alternative appears to be the erection of two Destructors, one at Kennedy Town in the west, the other in the vicinity of Causeway Bay in the east. The alternative possesses the advantage of disposing of the refuse on the outskirts of the City where any risk of nuisance is reduced to a minimum, while by the erection of two Destructors the distance of conveyance after collection will be considerably reduced.
I have previously described the uses to which a Destructor could be put if erected at Kennedy Town, but I venture to suggest that a Disinfector, and a furnace for cremating cattle, would also be useful at the east end of the City, while, if the heat generated be sufficient, the Destructor works there might eventually be utilized for pumping, in connection with the completion of the sewerage scheme for the City when this is carried out, which scheme includes pumping the sewage of the Eastern District out to North Point.
The initial cost, as well as the working expenses for two Destructors, will be greater than for one of equal capacity, but I believe the sanitary advantages will be found to thoroughly justify the addi- tional expenditure.
SCHEMES SUBMITTED.
Messrs. Goddard Massey and Warner.
I propose to deal first with the scheme of Messrs. GODDARD MASSEY AND WARNER.
This firm has had some experience in the East in the erection of a Destructor of two cells at Kurrachi, which is reported by the Municipal Engineer to burn eleven tons per cell per diem, and they consider that to calculate on a basis of nine tons per cell per day will allow a safe margin. Ten cells are therefore provided for the ninety tons.
The type of furnace proposed is that with the outlet flue at the back, behind the drying hearth and close to the feed opening. Provision is made to assist clinkering and to avoid the fire " caking," by the introduction of movable firebars which I have seen working successfully,
The scheme provides for the refuse to be tipped from the carts on to the floor over the cells, from whence it is raked into the charging hopper. This hopper is a simple contrivance for feeding the furnaces by means of which a measured quantity can be shot into them by pulling over a lever.
The fans would have been placed more advantageously if at the other end of the furnaces, for it is obviously a better arrangement that the stronger draught should be at the far end rather than in the middle of the flue; it has possibly been so arranged, however, in consequence of the provision asking for additional cells. The arrangement for regulating the draught to each furnace is worthy of attention; it will tend to counteract the disadvantage and assist in controlling the fires.
Placing the engines and fans, as shown between the furnaces and the boilers, will result in the temperature of the gases being unnecessarily reduced before reaching the latter and thus render them less effective. I have already pointed out the necessity of placing the boilers as close as possible to the furnaces.