Speaking at the last meeting of the Gaslight and Coke Company, Mr. George Livesey said many things with a view to inspire confidence of the future in the minds of timid gas proprietors. Among others he mentioned the advances now being made by invention in regard to improved appliances for developing the illuminating power of coal gas, with especial reference to a new burner just patented by Mr. Grimston. Mr. Livesey passed a very high encomium upon the burner, and this expression of opinion by such an authority is sufficient to arouse deep interest in the apparatus in question. It is therefore with much pleasure that we present our readers with the following early account of Mr. Grimston's burner, for which we are indebted to the inventor and Mr. George Bower, of St. Neots, in whose manufactory the burners are now being made in all sizes. It should be premised, to save disappointment, that the invention is yet so fresh that its ultimate capabilities are unknown. The accompanying illustration, therefore, represents the bare skeleton of one of the first models; and the actual performance of only the very earliest burner, made in great part by Mr. Grimston himself, has been fully tested.
Before proceeding to describe the invention, a brief history may be interesting of how it happened that Mr. Grimston, an electric lighting engineer, became a gas burner maker. The story will undoubtedly help to explain the reasons for many of the characteristics of the new burner.
IMPROVED GAS BURNER. FIG. 1.--Sectional Elevation.
It appears, then, that Mr. Grimston, who was connected with the electrical engineering establishment of Siemens Bros. & Co., Limited, was some months ago shown the construction and working of the Siemens regenerative gas burner, which is now sufficiently well known to render a description unnecessary here. In common with most spectators of this very ingeniously and philosophically designed appliance, Mr. Grimston was struck with its bulk and the superficial clumsiness of the arrangement whereby the air and gas supply are heated in it by the products of combustion. These lamps have, of course, materially improved of late; but when Mr. Grimston first saw them, perhaps 18 months ago, they certainly could not be called neat and compact in design. He at once grasped the idea embodied in these lamps, and set about constructing an arrangement which should be based on a similar principle, but at the same time avoid the inconveniences complained of. It is not too much to say that he has succeeded in both these aims, and the burner which now bears his name strikes the observer at once by the brilliant light which it produces by the simplest and most obvious means.
We may now describe, by reference to the accompanying illustrations, how Mr. Grimston produces the regenerative effect which is likewise the central idea of the Siemens burner.
IMPROVED GAS BURNER. FIG. 2.--Section through A B.
The light is simply that produced by an arrangement of a kind of Argand burner turned upside down. The central gas-pipe, a (Figs. 1 and 3), is connected to a distributing chamber, whence the annular cluster of brass tubes, a', a, (Figs. 1 and 2), are prolonged downward, forming the burner. The burner is inclosed in an iron or brass annular casing, b, b, which forms the main framework of the apparatus. The annular space which it affords is the outlet chimney or flue for the products of combustion of the burner beneath, and is crossed by a number of thin brass tubes, c, c, which lead from the outer air into the inner space containing the burner tubes, a', a', already described. The upper openings of the annular body, b, are shown at e, e (Fig. 3), which communicate direct with the chimney proper, e', e'. The burner is lighted by opening the hinged glass cover, d, which fits practically air-tight on the bottom of the body, so that the air needed to support combustion must all pass through the tubes, c, c, the outer ends of which are protected by the casing, k, k.
IMPROVED GAS BURNER. FIG. 3.--Section through C D.
When the gas is lighted at the burner, and the glass closed, the burner begins to act at once, although some minutes are necessarily required to elapse before its full brilliancy is gained. The cold air passes in through the tubes provided for it, and when these are heated to the fullest extent on their outside, by the hot fumes from the burner, they so readily part with their heat to the air that a temperature of 1,000° to 1,200° Fahr. is easily obtained in the air when it arrives inside, and commences in turn to heat the burner-tubes. The air-tubes are placed so as to intercept the hot gases as completely as possible; and also, of course, obtain heat by conduction from the sides of the annular body. It is evident that the number and dimensions of these tubes might be increased so as to abstract almost all the heat from the escaping fumes, but for the limitations imposed, first, by a consideration of the actual quantity of air required to support combustion, and, secondly, by the obligation to let sufficient ascensional power remain in the gases which are left to pass out through the upper chimney. If the gases are cooled too much, they will either fall back into the lamp and extinguish the flame, or will be removable only by the draught of a long chimney.
It will probably be the aim of the inventor to balance these requirements, and so to produce burners with very short or longer chimneys, according as appearance is to be consulted or the highest possible effect produced. The burner is a ring of brass tubes of considerable diameter, in proportion to the quantity of gas consumed, and thus provides for the delivery of gas expanded by heat. In connection with this device an explanation may be found of the failure of the British Association Committee on Gas Burners to find any advantage from previously heating the air and gas consumed. The Committee did not make the necessary provision for the increased bulk of the combustible and its air supply, caused by their heightened temperature; and the same quantity of gas measured cold (at the meter) could only be driven through the ordinary small burner holes at a velocity destructive of good results. Herr Frederick Siemens perceived this in his early experiments, and not only increased the orifices of his burners, but provided for the closer contact of the more rarefied gas and air by the use of notched deflectors, which are now an essential part of his apparatus.