The heating surfaces can be regulated to the utmost nicety, and may be raised to very high temperatures without the formation of steam. The system is, therefore, specially applicable for drying-closets and stoves for manufacturing purposes, where great heat is required, and where systems of hot-air flues are not expedient on account of danger from fire or damage by noxious vapours. Any degree of temperature up to 500° F. may be obtained.
In the “Acme” system the ordinary boiler is replaced by a series of specially constructed tubes, bent in tiers one over the other. The fire and heat are induced to travel over the whole surface of the tubes. The temperature of the tubes steadily increases throughout their entire length; hence great economy of fuel is secured. It is manifest that the temperature of the smoke, as it passes into the flue, need only be slightly in excess of the temperature of the return pipes, say about 190° F., whereas in the ordinary boiler, where perfectly free circulation is possible, and the temperature of the water is practically the same throughout, the heat of the flow-pipes governs that of the chimney. As the practical result, it may be said that about 90 per cent. of the calorific power of the fuel consumed is actually taken up and distributed by the heating surfaces of the “Acme” apparatus. This, as against 40 to 70 per cent. in the case of hot water, and steam boilers, or of cast-iron hot water apparatus (low pressure large bore-pipes), is a source of economy. Another notable source of economy is the remarkably small amount of fuel necessary to the effective working of the “Acme” system. The comparison between the two stands as 8 to 1, in consequence of the difference in the weight of the materials used in each system to obtain like results.
Buildings warmed by the “Acme” system are more thoroughly under control than where large pipes are used; the tubes being so small, contain but little water, consequently are more quickly heated, causing much greater rapidity of circulation. The temperature can be easily raised or lowered—automatically if desired—and the heat maintained for any length of time at pleasure. This is an obvious advantage in warming conservatories, as the temperature can be quickly raised when frost suddenly sets in, or lowered without opening the windows when a thaw commences. The heat of the house may be maintained at the requisite temperature without attention during the night, it simply being necessary to make the fire-place large enough to contain sufficient quantity of fuel, as the damper regulates the combustion. Where a moist heat is desired, such can readily be obtained at any given point by placing trays of water upon the pipes, or on a coil of pipes, thus giving the moisture so essential to the health of plants.
It has been supposed that the sediment from the water would soon choke the tubes, but as they are hermetically sealed there is no evaporation, and the same water being heated over and over again there is no deposit, and the remote possibility of incrustation is entirely overcome by using a small quantity of the patent anti-corrosion and non-freezing liquid.
There are no red lead or luting or perishable rubber joints used in connecting the pipes, but a perfectly solid metallic contact is made.
In applying the “Acme” apparatus to dwellings the warming pipes can be placed in any desired position along the skirting, under windows, coiled and covered by ornamental coil cases of various sizes and patterns, or pipes sunk beneath the floor in a channel. In the best rooms the pipes may be covered by iron gratings, of any design, to suit the other decorations of the building, while in servants’ rooms they may be placed in front of the skirting boards on suitable iron stands or brackets.
Fresh air is admitted into each compartment by an opening in the external wall through an iron box fitted with a valve to regulate the supply, and warmed by a surrounding coil of pipe. This can be placed beneath the windows, or when that is not convenient, in any other desired position, and if desired, may be covered with an ornamental iron coil case.
Warm water for bath and bedrooms may be drawn as required by having a cistern attached to the apparatus.
Lighting: Gas. Continued from p. [93].
An exceptionally good governor is that introduced by Joseph Shaw, of Albert Brass Works, Lockwood, Huddersfield, and 41, Hart Street, New Oxford Street, London, W.C. This is illustrated in Fig. 223. A searching trial of this governor was made a few months since, by Thos. Newbigging, Esq., M. Inst. C.E., who reports on it as follows:—