Staged combustion apparatus is disclosed for generating repetitive explosions. The apparatus includes a first chamber in which a gas under pressure is ignited by an ignition source, such as a spark plug, and a second chamber in which gas under pressure is ignited by gas discharging from the first chamber. The second chamber includes a discharge outlet and a dump valve is provided responsive to the gas pressures in the two chambers for permitting the discharge of gas under pressure from the second chamber when it is ignited. The gas discharge, for example, may be conducted about the tooth of a ripper plow to aid in earth fracture.
Rosser B. Melton, Jr.;John W. Colburn, Jr.;Charles D. Wood, III