Centrifugal piston expander

Apparatus for extracting energy from a pressured gas comprising:

• a body rotatable about an axis;
• power means for rotating said body;
• a pair of cylinder elements secured to said rotating body in diametrically opposed positions relative to said rotational axis;
• each said cylinder element defining an elongated fluid pressure chamber;
• a free piston movable longitudinally in each said fluid pressure chamber;
• said cylinder elements being fixed on said rotatable body with the path of movement of each said free piston extending from a position proximate to said axis to a position remote from said axis;
• whereby centrifugal force will move said free pistons to said remote positions;
• each said path of movement being substantially non-radially disposed relatively to said axis of rotation;
• inlet valve means communicating between a source of pressured gas and the remote end of each cylinder element;
• means for opening said inlet valve means only when said free pistons are respectively adjacent said remote positions to receive a charge of pressured gas in the respective fluid pressure chambers;
• thereby moving said free pistons inwardly toward said rotational axis;
• exhaust valve means respectively communicating with said fluid pressure chambers and openable only when said free pistons respectively approach said axis proximate position;
• and means on the radially inner end of each said cylinder element for producing a column of trapped gas for opposing radially inward movement of said free pistons to thereby stop the inward movements of said free pistons.

Apparatus for extracting energy from a pressured gas comprising:

• a body rotatable about an axis;
• power means for rotating said body;
• a plurality of cylinder elements secured to said rotating body in an equi-spaced array around said axis;
• each said cylinder element defining an elongated fluid pressure chamber;
• a free piston movable longitudinally in each said fluid pressure chamber;
• said cylinder elements being fixed on said rotatable body with the path of movement of each said free piston extending from a position proximate to said axis to a position remote from said axis;
• whereby centrifugal force will move said free piston to said remote position;
• each said path of movement being substantially non-radial relative to said axis of rotation;
• inlet valve means communicating between a source of pressured gas and the remote end of each said cylinder element;
• means for opening said inlet valve means only when said free pistons are respectively adjacent said remote positions to receive a charge of pressured gas in the respective fluid pressure chambers, thereby moving said free pistons radially inwardly;
• first exhaust valve means respectively communicating with said fluid pressure chambers and operable only when said free pistons respectively approach said axis proximate position;
• and a third valve means on the radially inner end of each said cylinder element for trapping air between said free piston and said radially inward end of said cylinder to stop the inward movement of said free piston.

The method of operating a centrifugal piston expander to extract heat and mechanical energy from a pressured gas, said expander having at least one elongated cylinder mounted for rotation about an axis and defining an elongated fluid pressure chamber extending from a point remote from the rotational axis to a point proximate to the rotational axis, and a free piston slidably and sealably mounted in the fluid pressure chamber, comprising the steps of:

• (1) rotating the cylinder to move the free piston by centrifugal force to the radially outer end of the fluid pressure chamber;
• (2) introducing a charge of pressured gas in the radially outer end of the fluid pressure chamber, thereby moving the free piston inwardly and rotating said cylinder about said axis to produce an output torque;
• (3) closing a normally open exhaust valve in the inner end of the fluid pressure chamber to provide a trapped volume of air to stop the inward movement of the free piston;
• and
• (4) continuously repeating steps 1-3.