Description of the Process of Manufacturing Coal Gas, for the Lighting of Streets Houses, and Public Buildings / With Elevations, Sections, and Plans of the Most Improved Sorts of Apparatus Now Employed at the Gas Works in London and the Principal Provincial Towns of Great Britain; Accompanied With Comparative Estimates, Exhibiting the Most Economical Mode of Procuring This Species of Light

by Friedrich Christian Accum

Between the inlet pipe which conveys the gas into the governor, and the outlet pipe which conveys the gas into the mains, is fixed horizontally a partition plate, having a circular aperture in the centre. This plate is seen between the letters x, T.

Through this orifice passes a perpendicular axis P, which is fixed at the top in the centre of the regulator or interior floating vessel u, x, y, z.

The interior extremity of the axis P, is furnished with a cone, having its base downwards, and projecting beyond the pipe a, x, into the short cylinder G, H. The base of this cone slightly exceeds the diameter of the orifice x, T, so as to close up entirely, when the regulator is raised to its greatest height in the outer vessel A, B, C, D. But when the floating vessel u, x, y, z, descends in the outer vessel A, B, C, the vertex of the adjusting cone P, is just entering the aperture.

The regulator is conical, and its form is in exact proportion to the loss of the weight of water which it displaces; so that the gas conveyed into it always retains an invariable density at whatever height the regulator may be immersed in the water in the outer vessel. If the outer vessel be filled with water up to the top of the central branch pipe, the interior vessel will float, and the water will stand in the outer vessel at the same height as in the inside of the regulator; hence the density of the gas within will be the same as the outer air. But the density of the gas in the regulator may be increased at pleasure by applying a weight to the top of the regulator, the water will then stand higher on the outside of the regulator than within, and this adjustment will remain uniform, because the quantity of matter of the regulator is in the ratio of its specific gravity or loss of weight as it becomes immersed in the water.

Let us suppose that the pipe above the partition plate be connected with a main, and that the outlet pipe below the partition plate be connected with a gas holder supplying gas into the machine; it will be evident that if the density of the gas in the inlet pipe becomes by any means increased, a greater quantity of gas must pass betwixt the sides of the adjusting cone and the aperture in the partition plate, the consequence of which will be that the floating regulator will rise, and therefore contract the area of the partition plate. And if, on the contrary, the gas in the inlet pipe decreases in density the regulator will descend, so that whatever density the gas may at any time assume in the gas holders or mains, its density in the floating vessel u, x, y, z, will remain uniform, and consequently the velocity of the gas passing into the mains will be regular.

For when the aperture of the partition plate would admit more gas than what is necessary for the density of the gas in the mains, the floating regulator rises, and by that means raises the adjusting cone to diminish the aperture in the partition plate, and when, on the contrary, the aperture does not allow a sufficient quantity of gas to come from the gas holders, the gas passes out of the regulator into the mains, and in so doing the regulator descends, and consequently the adjusting cone increases the opening to admit the requisite gas into the mains.

The further application of this machine, for regulating the height of the gas flames issuing from burners or lamps of different kinds will be shewn hereafter.

Gas Holder with Governor or Regulating Guage at the Gas Works Chester.

Fig. 7, [plate VI.], exhibits a perpendicular section of the gas holder at Chester. A, A, are wooden beams or pillars fixed into sockets or shafts constructed on the outside of the brick-work, and descending as seen in the design to the depth of the tank. There are four of these pillars, three only are seen in the section. B, B, are round iron guide rods rendered steady by stays at the upper extremity of the rods.

To the upper and lower edges of the gas holder are fastened eye bolts, C, C, through which the guide rods, B, B, are inserted, so that the gas holder must move steadily and firmly. D, E, are the inlet and outlet pipes which convey the gas into and out of the gas holder.