A hand-held inflation device comprising: a first housing (10) in which a motor (11) is mounted; a second housing (20) in which a compression means (21) for generating compressed air is mounted; the second housing (20) is rotatably mounted to the first housing (10) such that the second housing (20) is foldable relative to the first housing (10) between a folded position and an extended position; coupling means (22) for coupling the motor (11) to the compression means (21) in at least one position between the folded position and the extended position, such that the motor (10) is capable of driving the compression means (21).

A rotary piston and cylinder device (1) comprising a rotor (2), a stator and a shutter disc (3), the rotor comprising a piston (5) which extends from the rotor into the cylinder space, the rotor and the stator together defining the cylinder space, the shutter disc passing through the cylinder space and forming a partition therein, and the disc comprising a slot (32a) which allows passage of the piston therethrough, and a surface of the rotor and a surface of the stator opposing each other forming a close-running surface pair, and at least one of the surfaces comprising an abradable coating (10) which is provided with a plurality of recess formations, and the recess formations are discontinuous from each other.

A rotary piston and cylinder device (1) comprising a rotor (2), a stator and a shutter disc (3), the rotor comprising a piston (5) which extends from the rotor into the cylinder space, the rotor and the stator together defining the cylinder space, the shutter disc passing through the cylinder space and forming a partition therein, and the disc comprising a slot (32a) which allows passage of the piston therethrough, and a surface of the rotor and a surface of the stator opposing each other forming a close-running surface pair, and at least one of the surfaces comprising an abradable coating (10) which is provided with a plurality of recess formations, and the recess formations are discontinuous from each other.

A rotor mechanism for use in moving fluid. The rotor mechanism has six rotor units spherically arranged, with at least one rotor unit including a port through it's body. Each rotor has the form of a truncated cone with two symmetric spiral recesses provided on the lateral surface of the rotor which acts to cooperate with the adjacent rotors. Rotation of at least one rotor unit causes rotation of adjacent rotor units which thereby moves fluid without compression between the outside of the mechanism and the port via a central substantially spherical free space cavity formed by the cooperation of inner surfaces of the rotor units. The rotor mechanism is fully submersible.

A rotor mechanism for use in moving fluid. The rotor mechanism has six rotor units spherically arranged, with at least one rotor unit including a port through it's body. Each rotor has the form of a truncated cone with two symmetric spiral recesses provided on the lateral surface of the rotor which acts to cooperate with the adjacent rotors. Rotation of at least one rotor unit causes rotation of adjacent rotor units which thereby moves fluid without compression between the outside of the mechanism and the port via a central substantially spherical free space cavity formed by the cooperation of inner surfaces of the rotor units. The rotor mechanism is fully submersible.

A rotor for a rotary piston and cylinder device (1), wherein at least part of an outer surface (30) of the rotor (22) is a substantially frusto-conical shaped surface.

A rotor for a rotary piston and cylinder device (1), wherein at least part of an outer surface (30) of the rotor (22) is a substantially frusto-conical shaped surface.

A fluid moving apparatus includes an electric motor having a rotor and a stator and a fluid displacement member. The rotor rotates relative to the stator on a common axis to generate a rotational output. The rotational output is provided to the fluid displacement member to power the fluid displacement member to one of move linearly along and rotate about the common axis. The stator includes one or more coils configured to power rotation of the rotor. The one or more coils extend circumferentially around and can be coaxial on the common axis.

A fluid moving apparatus includes an electric motor having a rotor and a stator and a fluid displacement member. The rotor rotates relative to the stator on a common axis to generate a rotational output. The rotational output is provided to the fluid displacement member to power the fluid displacement member to one of move linearly along and rotate about the common axis. The stator includes one or more coils configured to power rotation of the rotor. The one or more coils extend circumferentially around and can be coaxial on the common axis.

A screw compressor includes a screw rotor, a plurality of gate rotors, a casing with a cylindrical wall, and an adjustment mechanism to adjust a pressure of a fluid in the casing. A plurality of compression chambers are formed inside the cylindrical wall by the screw rotor and the gates. The plurality of compression chambers include a first compression chamber in which the fluid introduced into the casing with a suction pressure is compressed to a pressure higher than the suction pressure, and a second compression chamber to which the fluid compressed in the first compression chamber is sent via an intermediate pressure space. The adjustment mechanism adjusts an intermediate pressure, which is a pressure of the fluid in the intermediate pressure space, in a two-stage operation in which the fluid is compressed in the first compression chamber and the second compression chamber.