One feature of the lamp that requires special attention is the opening G, through which the vapor from the generator is discharged into the induction tube. This is a very small opening and occasionally becomes stopped or partly closed. When this occurs the lamp fails to receive the necessary amount of gas, and the light is unsatisfactory. In this lamp, the cleaning needle Q is provided for removing the stoppage. The needle is simply screwed into the opening and forces out the obstruction; when it is withdrawn, the opening is left free. A more convenient device for accomplishing the same purpose is described in the portable lamp, Figs. 195 and 196.
Portable Gasoline Lamps.
—The portable form of desk and reading lamps for the use of gasoline is made in a great variety of styles. They are sometimes constructed to feed by gravity, but by far the greater number are operated by the pressure method. The portable lamp must be a complete gas plant, with storage tank for the gasoline, pipe system for conducting the gasoline to the lamp, generator and burner. To give satisfactory results, the lamp must be capable of being lighted with the least degree of trouble and operated with the least amount of care. The immense number of lamps of this kind that are sold shows that they meet all of these requirements and have proven satisfactory in operation. Their greatest attractiveness is their capability of giving a very large amount of light at relatively low cost.
Fig. 195 illustrates a portable gasoline lamp in which a convenient and efficient form of generating mechanism is combined with an attractively proportioned exterior. The lamp works on the principle of the hollow-wire system, the base serving as a storage and pressure tank, the frame of the lamp acting as the tube for supplying the lamp with gasoline, and the canopy containing the generating mechanism.
Fig. 195.—Portable gasoline mantle lamp.
The tank in the base is filled with gasoline at the opening E, which is made air-tight by a screw-plug. The plug also contains an attachment piece for the air pump, which furnishes the pressure to the gasoline. The hollow standard reaches to the bottom of the tank and through it the gasoline is forced to the point marked A, where the gasoline enters the generating mechanism. This part of the lamp, which is entirely concealed by the lamp canopy, is shown in detail in Fig. 196. The reference letters in Fig. 195 apply to the same parts in the detail drawing.
The gasoline enters an asbestos-packed tube F at the point A, and after percolating through the tube, reaches the regulating valve at the point G. The hand-wheel B opens and closes the valve, and thus controls the entrance of the gasoline to the generating tube H, where it is converted into the vapor. The vapor now needs only the addition of air to make it the desired gas for illuminating the mantle.
The vapor from the generating tube escapes at the small hole K, located directly under the mixing chamber M. The supply of air is received through the tube C, provided with a regulator, which is readily accessible from the outside of the lamp. The mixture of gasoline vapor and air is accomplished as in the other lamps described, through the Bunsen tube N. In this case, the Bunsen tube is extended and increased in size to produce a mixing chamber of considerable volume. The mantle is attached to the tip O. The tip, like the one already described, is made of German silver and constructed to produce a flame that will entirely fill the mantle.
This lamp is provided with a special means of keeping the opening K free from accumulations. The opening K, through which the gasoline vapor escapes from the generator, is very small and a slight stoppage will materially interfere with the flow of the vapor and thus impair the illuminating effect of the light. A lever D operates an eccentric which engages the piece P, to which is attached a pin that readily enters an opening K, when the lever is turned. Any accumulation which may lodge in the opening is instantly removed and the needle returned to its place by a turn of the lever D.