Inverted Cylinder Engine.— A vertical en gine, in which the cylinder is inverted or placed above the piston rod, connecting rod and crank shaft. It is typical of the manne engines em ployed to drive screw propellers.
Inclined Engine or Inclined Cylinder En gine.— A form of marine engine in which the cylinders are inclined toward each other at an angle of about 120 degrees and make a triangle with the base. They are connected by cranks to a common crank-shaft.
Beam Engine.— An indirect-acting engine in which the piston rod is connected to the con necting rods by means of a lever in the form of a beam. It is more fully described under the term Indirect-Acting Engine.
Oscillating Engine, A marine engine of the direct-acting type, in which the cylinders are suspended upon -hollow trunnions and oscil late thereon, thus allowing the motion of the piston rods to accommodate itself to that of the crank at all parts of the revolution. It occu pies but little space and is peculiarly adapted for paddle-wheel steamers. It survives mainly in toy engines because of its simple con struction.
Trunk Engine.— An engine having a large hollow piston open at one end and called a trunk The connecting rod goes right into the open end of this trunk-piston and is attached directly to the piston-head, so that there is no piston rod. It is used in some forms of gas engines and toy engines.
Corliss Engine.— A very economical type of engine, in which the valves are controlled auto matically from the governor aud the steam sup ply .proportioned to the requirements of the engine at each moment during its working stroke. The valve forms a segment of a circle and turns through an arc of a circle and alter nately covers and uncovers the steam port. It is operated by a rod from a wrist plate, but is disconnected at every stroke of the engine and the supply valve closed instantaneously by means of a dash-pot.
Cornish Engine.—A standard type of pump ing engine, originally of the single-acting type. At the present time it appears in two forms — the beam engine and the direct-acting engine. The valves of a Cornish engine are operated by a special device called a cataract, consisting of a weighted piston which works in a cylinder provided with a large inlet valve and a small discharge valve. The worlcing stroke of the
pump lifts the weighted piston and draws the water into the cylinder through the former, and the return stroke discharges it through the latter and at the same time actuates the valves of the steam cylinder of the pump so as to cause another worlcing stroke.
Marine Engine.— Any form of engine used for propelling a vessel. They are usually of the compound or multiple-expansion type.
Stationary Engine.— An engine on fixed foundations, as distinguished from the locomo tive, portable and marine engines.
Locomotive Engine.— A high pressure steam engine and multitubular boiler complete, mounted on a carriage and provided with suitable wheels to enable it to draw loaded cars upon a permanent way or railway track See LocomarivE.
Portable Engine.— A small engine of the locomotive type, motmted on a carnage which permits of its being moved from place to place for use in connection with work of a temporary character. Portable engines are extensively used for agricultural purposes and for general traction purposes on ordinary highways.
Gas and Oil Engine&—These classes of heat engines are commonly designated as in ternal-combustion engines. See INTERNAL COM BUSTION ENGINE and DIESEL ENGINE.
The Slide-Valve.— The introduction of the slide-valve for operating the ports of a steam engine marked a distinct advance in economy, because it can be made at exactly the right time and also because it admits the hot steam to the cylinder through a port which has just been cooled by the exhaust. As ordinarily con structed the slide-valve is a sliding D-shaped piece in the steam-chest, moving back and forth over the three ports— the two end-ports of the cylinder and the exhaust port in the centre and permitting the steam to pass alternately to either end of the cylinder to push the piston and opening the exhaust for the release of the used steam. There are °laps* at the end of the D whose length determines the instant at which the ports shall begin to open. These laps are known as outside or steam-lap, and inside or exhaust-lap. The slide-valve has also been de veloped for automobile use in the Knight type of engine.