GB1289094A - - Google Patents

Abstract

1289094 Aerating liquids C R BARSBY 1 Dec 1969 [29 Aug 1968] 41296/68 Heading B1C [Also in Divisions B7 and Fl] A method of accelerating a stream of liquid through a pipe, for use in marine water jet propulsion, land-based turbine operation, (see Division Fl), or fire-fighting, comprises injecting a gas under pressure into a section of the pipe at or near its outlet end in a quantity greater than that of the liquid passing through the section, such that the gas mixes with the liquid to form a dispersion of bubbles small compared with the pipe diameter. The apparatus shown comprises a pump 1 and a compressor 6 driven by a common prime mover 9, the pump inlet 2 facing forwardly of the propelled boat and the water pumped being supplied at constant velocity to pipe 3 having a perforated section 4 through which gas from compressor 6 is injected via pipe 7 and chamber 5. The gas may be air or may be combustible, a sparking plug 8 being provided to continuously ignite the combustible gas. Additional gas may be supplied downstream of section 4 to produce large bubbles, Fig. 2 (not shown), and the outlet end of the pipe may be surrounded by a chamber with an outlet nozzle, the chamber being supplied with gas under pressure to induce flow from the pipe outlet. The gas source alternatively may be the exhaust of the prime mover, Fig. 3 (not shown). Reversing of the propulsion thrust may be effected by a U-shaped pipe hinged to the outlet of pipe 3, and movable into or out of communication with the outlet, Fig. 4 (not shown). For fire fighting, pressurised gas, e.g. free of oxygen so as not to support combustion, is supplied to a chamber surrounding a perforated section of hose.