GB498882A - Improvements in and relating to hot air power plant - Google Patents

Abstract

498,882. Hot-air engines and plant. BRUCE, J. S. July 13, 1937, No. 19408. [Class 7 (i)] A hot-air power plant is of the kind in which air is compressed in the power cylinder or cylinders a or in an enginedriven compressor c and is heated in external air-heating apparatus g, and in which the expanded air exhausted from the engine is utilized to support the combustion of the fuel used in the air heater, and to control the temperature of the heating gases. A heat exchanger k provided in the air heater enables the exhaust air from the engine, before being used to support combustion and to control the temperature in the air heater, to be preheated by the waste gases from the air-heating chamber of the apparatus after they have been used to heat the working air. In the form shown, the plant comprises two-stroke double-acting power cylinders a, with chambers b housing mechanically actuated inlet and exhaust valves, and engine-driven compressors comprising lowpressure cylinders c and high-pressure cylinders c<1>, each double-acting, with automatic or mechanically actuated valves. The cylinders c are water-cooled and an intercooler c2 is provided. High-pressure air from cylinders c<1> is led through pipes f and a reservoir f<2> to coils g<2> in the heater g, and thence through a pipe g<4> and branches g<7> to the engine. Exhaust air from the engine is conveyed by branch pipes j to a valve j<2>, which allows part of the air to escape through a pipe j<3> to the atmosphere or to the heating apparatus of a building or ship, while the remainder is led by pipes j<5> through the heat exchanger k and thence through pipes j<6> to the combustion chamber n of the heater. A portion of this air is conveyed by branch pipes j<7> to the oil burners m to provide primary air for combustion. Doors n<2>, n<3> for diverting the hot gases from the chamber n through a pipe n<4> to the atmosphere may be operated by a hand wheel on a vertical shaft serving also to operate a control valve g<5> in the air pipe g4, a fuel-supply valve h<8> for the air heater, and a valve connecting the reservoir f<2> to an independent air compressor for starting purposes. In modifications, (1) the independent compressor cylinders c, c<1> are dispensed with, the air being compressed in the power cylinders, which work on a four-stroke cycle; (2) compressor and power cylinders are arranged in tandem and are provided with piston valves, the power pistons and their valves working with clearance while the compressor pistons and their valves are close-fitting ; the cylinder covers and glands are cooled by exhaust air or other cooling fluid. The Provisional Specification states also that the exhaust air from the engine may be used to heat the combustion air for the hot-air generator.