A cryogenic fluid pump includes a drive assembly and a pumping assembly. The drive assembly includes a cylinder. The cylinder includes an annular dump channel formed in and extending about an interior wall of the cylinder. A piston is reciprocatable within the cylinder between a first and second position. A hydraulic pressure chamber is defined by the cylinder and the piston. The piston includes an axial spill passage in communication with the pressure chamber and a transverse spill passage in communication with the axial spill passage. The transverse spill passage includes a piston dump port which is sealed to the cylinder in the first position and in the second position unsealed to the cylinder to permit fluid exit from the pressure chamber. The second position includes an over travel state and the dump area of the piston dump port when unsealed to the cylinder increases as the piston advances.

A device and method for treating a wound of a patient with negative pressure is provided. The device comprises a heat-assisted pump system. The pump system can be powered in part by heat derived from the patient. The pump system may be configured to be highly planar, light weight, and portable. The pump system may comprise a Stirling engine or a thermal acoustic engine.

A device and method for treating a wound of a patient with negative pressure is provided. The device comprises a heat-assisted pump system. The pump system can be powered in part by heat derived from the patient. The pump system may be configured to be highly planar, light weight, and portable. The pump system may comprise a Stirling engine or a thermal acoustic engine.

An air motor (10) that has opposing chambers (16, 17) to which compressed air is alternatively delivered to drive the motor (10). The motor (10) has a primary valve (52) that governs deli very of the compressed air to the chambers (16, 17) so at least part of the compressed air is transferred to the other chamber to aid in driving the pistons (18).

An air motor (10) that has opposing chambers (16, 17) to which compressed air is alternatively delivered to drive the motor (10). The motor (10) has a primary valve (52) that governs deli very of the compressed air to the chambers (16, 17) so at least part of the compressed air is transferred to the other chamber to aid in driving the pistons (18).

An engine can include at least one piston, a block, a fluid delivery system, and an output shaft. The block can define at least one cylinder. The piston can be received in the cylinder. The piston can be operable to reciprocally move rectilinearly while positioned in the cylinder. The fluid delivery system can be operable to communicate air and combustible fuel to the cylinder. The piston can be operable to compress the air and combustible fuel. The output shaft can be driven in motion by the piston and extend beyond the block to a distal end. The output shaft is limited to rectilinear movement.

An engine can include at least one piston, a block, a fluid delivery system, and an output shaft. The block can define at least one cylinder. The piston can be received in the cylinder. The piston can be operable to reciprocally move rectilinearly while positioned in the cylinder. The fluid delivery system can be operable to communicate air and combustible fuel to the cylinder. The piston can be operable to compress the air and combustible fuel. The output shaft can be driven in motion by the piston and extend beyond the block to a distal end. The output shaft is limited to rectilinear movement.

Disclosed herein is an apparatus for extracting thermal energy from thermal expansion of a working medium in the apparatus. The apparatus includes a thermal expander, a compressor for compressing the working medium after the expansion, and a force modulation unit connecting the thermal expander to the compressor. The force modulation unit consists of two conversion gears that are connected by a lever system. The lever system can be dynamically controlled so that the non-constant force from thermal expansion is modulated into a substantially constant output force of the apparatus.

An arrangement includes a combustion-free reciprocating engine having a cylinder closed by a cylinder head and a negative pressure chamber.

A piston is coupled to a crankshaft via a connecting rod. The connecting rod and the crankshaft are integrated in a crankcase of the reciprocating engine.

The cylinder head has an inlet valve and an outlet valve. The vacuum chamber is connectable to a working chamber of the cylinder via the outlet valve, to generate a negative pressure in the working chamber, and to the atmosphere (A) surrounding the reciprocating engine via the inlet valve to generate ambient pressure in the working chamber.

A valve control controls the intake and the exhaust valves such that the piston is moved back and forth by alternately applying ambient pressure and negative pressure

There is always a substantially constant pressure, in a region of the piston facing away from the cylinder head.

An arrangement includes a combustion-free reciprocating engine having a cylinder closed by a cylinder head and a negative pressure chamber.

A piston is coupled to a crankshaft via a connecting rod. The connecting rod and the crankshaft are integrated in a crankcase of the reciprocating engine.

The cylinder head has an inlet valve and an outlet valve. The vacuum chamber is connectable to a working chamber of the cylinder via the outlet valve, to generate a negative pressure in the working chamber, and to the atmosphere (A) surrounding the reciprocating engine via the inlet valve to generate ambient pressure in the working chamber.

A valve control controls the intake and the exhaust valves such that the piston is moved back and forth by alternately applying ambient pressure and negative pressure

There is always a substantially constant pressure, in a region of the piston facing away from the cylinder head.