Page:The New International Encyclopædia 1st ed. v. 04.djvu/76

* CAIiORIC ENGINE. 54 CALOKIC ENGINE. top of the hot cyliniler. B, and vice versa through heatinj; and cooling clianibers, C and D, contain- ing Stirling regenerators. The arrangement of -■V_J.L. PIO. 4. RIDER CALORIC ENOINIS. I^^ tesfe^^k^^^^^ one of these engines was exhibited at the Paris Exposition of 18.55. This same principle was embodied in an engine patented by the famous engineer Sir William Siemens, in 18(10, but he neglected to put it into practical use. The Siemens engine employed four cylinders, each hot at one end and cold at the other, all con- nected to one shaft, and so arranged that the hot end of one communicated through a regenera- tor with the cold end of the next. The heat was supplied by hot products of combustion from pro- ducer gas in a chamber connected with the hot ends of the cylinders, while the opposite ends were fitted with refrigerating devices. One of the latest forms of compression engines is the Rider, shown by Fig. 4. In this sectional view C is the cold cylinder or compression cylinder, surroimded by the water-jacket, E, and t) is the hot cylinder. The compressed air from the cold cylinder is changed throigh the regenerator, H, to the hot cylinder, where it is expanded by the heat from the grate underneath the evlinder. the pistons was such that the air was compressed in the cool cylinder; passed through the regenera- tor into the hot cylinder, where it was ex])anded ; then transferred to llie cold cylinder through the cooling chamber, and the cycle repeated. From four to six cylinders, each double-acting, were proposed to be combined in a series. A model of 1 Fia. 5. HOT-AIR PHODUCT OF COMBU8TIOX ENGINE. Hot-air engines employing internal combus- tion, like compression engines, form a separate class of this type of motor. At the outiset of their consideration, however, it is im]H>rtaiil to note a somewhat arbitrary distinction between them and the internal combustion motors known as gas-engines. The true gas-engine is limited generally to internal-combu.stiou engines, in which the air, mixed with gas or with oil-vapor, is admitted to the cylinder and ignited after its admission. Liquid or gaseous fuels arc essential in this type of engine. Hot-air internal-combus- tion engines, or, more properly, hot-air products of combustion engines, operate by forcing atmos- pheric air through a closed fire, which may be and generally is a solid fuel lire, and carrying the air and gases of combustion to the engine cylin- der. One form of such air-engines is shown by- Fig. 5. The furnace was i)laeed in a chamber strong enough to withstand the pressure. The compressing pump li forced air Vielow the ash-pit up through the fire, where it was expandcil by heat and by combustion with carbon. Being ad- mitted to the working cylinder against the pis- ton, it was exhausted into the chinmey. The fur- nace had to be charged with fresh fuel tlirough a combination of double doors, U, working on the principle of an airlock. A hot-air product of combustion engine was described by Sir tJeorge Cayley, an Knglishman, in 1807 and 18'2.'j, and again in 1S.37 this inventor ])atented a modifica- tion of the same design and built several engines, none of which gave any marked success. In 1821 Dr. Neil Arnott (q.v.), the celebrated scientist, took u]) the same idea and patented a form of engine in which, to avoid the abrading action of