BROOMAN'S PATENT DRY GAS METER.* [Patent dated November 3, 1845; Specification enrolled May 3, 1846. Communication from abroad.] FIG. 1 is a front elevation, partly in section of this newly invented dry gas meter. Fig. 2 a side view of it, and fig. 3, a top plan. In each of these figures, so much of the external casing as covers the parts represented in it, is supposed to be removed. A is a partition which divides the meter horizontally into two rearly equal compartments, C and C. The area of each compartment is reducible by a certain constant quantity by means of an expandible vessel, D, placed in an inverted position (with its mouth downwards, as it were,) and attached to a ledge, 7, which projects from the sides of the compartment all round a little way above the bottom. Each of these vessels consists of a circular ring, m1, and a circular plate, m2, of larger dian cter than the ring, connected together by a flexible expanding belt, n. I is the inlet-pipe, for admitting the gas from the main into the hood B; and O, the outlet-pipe for conveying it to the burners. E is a valve box, and p1 p2 ps p4, pipes con municating between it and the compartments, C1 C2, cne set of these pipes conveying the gas to the under parts of the compartments where they open into their respective expanding vessels D, and the other set conveying it to the part which is above, or external to the expanding vessels. V and V2 are two sliding valves which command the passages, p1 p2 p3 p4, and are worked in manner following: The upper vessel, D1, is conrected by a vertical link, d, rassed up through the centre of it as shown separately in figure 4, with two horizontal and parallel levers, L3 and L*, one above and the other below the vessel, the former of which is connected to a balanceweight, W, and the latter is connected by means of a vertical spindle, T, carried through a stuffing-box y' (fig. 3) to a compound lever, L', which is connected by its longer arm and a connecting-rod, R2, to a crank, K, and by its short arm to the sliding valve, V2. The under vessel, D2, is in like manner connected with and works the crank K, and the valve, V2, through the medium of the * Manufactured by Messrs Platow and Co., High Holborn. lever, L2, link, Ls, the spindle, T2, (carried through a stuffing-box, y2,) and the lever, L (with weight, W2, attached to it); Z is a screwed shaft, connected with the crank, K, the thread of which acts on the train of wheels of the registering index, X. The gas being admitted into the compartments, C C2, alternately beneath and above, or inside and outside of the two inverted vessels, it Expands these vessels in the one case, and compresses them in the other; and as each vessel, by its expansion, displaces one constant quantity of gas, and each expansion is communicated to the index through the medium of the levers, connecting-rods, &c., before described, the instrument becomes an uncrring register of the quantity of gas consumed. The flexible sides of these vessels do not touch the external case of the meter in any part, so that they are not subject to any wear from friction; and are, under all circumstances, perfectly free and unimpeded in their action. They may be made either of leather or of any other membranous substance sufficiently strong and flexible, or of vulcanized caoutchouc, or of gutta percha either sulphurised or unsulphurised; or of any textile fabric rendered impermeable to gas under all ordinary pressures, by some coating or varnish (such as a solution of gutta percha) not liable to be affected by the gas. But of whatever material they may be composed, they should be without seam or side joint, and this, in the case of leather, may be effected by cutting them out of the solid, or, in the case of gutta percha, by casting them in moulds, or forcing the gutta percha in a plastic state through tubular dies; or, in the case of the textile fabrics, by weaving them after the manner of looped fabrics. The office of the weights, WW2, is to balance the weights of the vessels, D1 and D2, and this they should do exactly. Between the two sliding valves, V1 and V2, a small piece of sponge saturated with oil may be fixed for the purpose of keeping the seats of the valves constantly lubricated. S (fig. 1) is a tube or syphon for drawing off any liquid deposits which might interfere with the action of the meter. When it is opened at bottom for this purpose, by unscrewing |