Abstract: An improved electromechanical transducer is provided. In an embodiment, the transducer comprises at least two flux modules, each defining a magnetic circuit having a gap; an armature configured to move along a longitudinal axis passing through the gaps; and a gas containment structure laterally surrounding the armature, wherein: the at least two flux modules are provided outside the gas containment structure; and the armature comprises a reinforcing portion laterally outside of the gaps that is wider in a direction parallel to the flux in the gaps than at least one of the gaps.

Abstract: Stirling cycle machines, including engines and coolers or heat pumps are described.

Abstract: There is disclosed a cold head for a pulse tube cooler, comprising: a regenerator having a first end connectable to a compressor; a pulse tube having a first end and a second end; a heat exchanger connected between a second end of the regenerator and the first end of the pulse tube; and a phase control device connected at the second end of the pulse tube for controlling the flow dynamics in the pulse tube to provide cooling at the heat exchanger, thereby maintaining a negative temperature gradient between the first and second ends of the regenerator, wherein: the pulse tube comprises a wall having a porous portion for allowing a working gas to enter or leave the pulse tube directly through the porous portion, the porous portion being nearer to being parallel than perpendicular to the temperature gradient between the first and second ends of the regenerator.

Abstract: Various arrangements are disclosed based on springs formed from a plurality of individual resilient arms, including a spring having a substantially planar form in an unloaded state and rotational symmetry of at east order two about a symmetry axis perpendicular to the plane of the spring, the spring comprising: an inner hub and an outer hub, the inner hub being radially inward with respect to the outer hub; a plurality of resilient connecting arms each connected at an inner end to the inner hub and at an outer end to the outer hub, the plurality of resilient connecting arms being configured to provide a restoring force parallel to the symmetry axis when the inner and outer hubs are displaced relative to each other along the symmetry axis; wherein the inner hub, the outer hub and each of the plurality of resilient connecting arms are formed as physically separate elements and are connected to each other during assembly to form the spring.

Abstract: An improved electromechanical transducer is provided. In an embodiment, the transducer comprises at least two flux modules, each defining a magnetic circuit having a gap; an armature configured to move along a longitudinal axis passing through the gaps; and a gas containment structure laterally surrounding the armature, wherein: the at least two flux modules are provided outside the gas containment structure; and the armature comprises a reinforcing portion laterally outside of the gaps that is wider in a direction parallel to the flux in the gaps than at least one of the gaps.

Abstract: Stirling cycle machines, including engines and coolers or heat pumps are described.

Abstract: A linear, multi-cylinder Stirling cycle machine comprises a plurality of Stirling cycle units arranged in an open series or closed loop. Each of the units comprises a compression space in fluid communication with an expansion space via a regenerative heat exchange assembly. The compression space and expansion space are in fluid communication with, respectively, a compression piston and an expansion piston, and the separate Stirling cycle units are mechanically coupled together by linear power transmitters, which connect the expansion piston of one unit to the compression unit of the other. The linear power transmitters can be linear transducers such as linear motors or generators. In the open series arrangement the series of Stirling cycle units can have an initiating compressor at one end and a terminating expander at the other end. hi the closed loop arrangement, one of the Stirling cycle units can include an exergy throttle to restrict gas flow rates to control the speed of the machine.

Abstract: Various arrangements are disclosed based on springs formed from a plurality of individual resilient arms, including a spring having a substantially planar form in an unloaded state and rotational symmetry of at least order two about a symmetry axis perpendicular to the plane of the spring, said spring comprising: an inner hub and an outer hub, said inner hub being radially inward with respect to said outer hub; a plurality of resilient connecting arms each connected at an inner end to said inner hub and at an outer end to said outer hub, said plurality of resilient connecting arms being configured to provide a restoring force parallel to said symmetry axis when said inner and outer hubs are displaced relative to each other along said symmetry axis; wherein said inner hub, said outer hub and each of said plurality of resilient connecting arms are formed as physically separate elements and are connected to each other during assembly to form said spring.

Abstract: An improved method and system for removing blockage from hydrocarbon transfer conduits (108). An apparatus and methods for cleaning a hydrocarbon transfer conduit is disclosed whereby a laser head (104) is placed in a hydrocarbon transfer conduit to be cleaned and supplied with a laser beam. The laser head applies the laser beam to an area in the hydrocarbon transfer conduit to be cleaned.

Abstract: An electromagnetic transducer which may be driven as a linear electric motor (which may be a permanent magnet motor or a variable reluctance motor) in which coils disposed around first and second cores are positioned on opposite sides of a longitudinal plane in which the longitudinal axis of the armature lies. The transducer may be arranged to work as a generator.

Abstract: The invention provides for the monitoring and control of a system, such as a linear electro-mechanical transducer, e.g. a linear electric motor, particularly when driven in a reciprocating manner. A dynamic model of the linear motor and its load is used to calculate from the input drive to the motor a predicted response of the motor. The predicted response is compared to a measured response and the model parameters are varied by global optimisation until the two match as closely as desired. The drive may be the voltage input to the electrical motor and the response may be the electrical current in the motor coils. The parameters and variables of the model, after optimisation, can be taken as good estimates of the actual operating parameters and variables of the linear motor. This gives a measurement of such quantities as the stoke and offset of the linear motor. The invention is particularly applicable to the use of linear motors to drive compressors, for instance in Stirling cycle coolers.

Abstract: A linear compressor motor comprising a piston assembly (2) and a cylinder assembly (3) mounted together for relative axial movement along an axis (1) by a pair of spiral springs (16, 17). The piston assembly (2) includes a piston (6) and the cylinder assembly (3) including a cylinder (4), there being a low clearance between the cylinder and the piston to enable a pumping action to be achieved without seals. Mounted on the exterior of the cylinder (4) is a magnet (13) and associated polepiece (14). Forming part of the cylinder assembly (3) is a cylindrical housing (11) in which the cylinder itself is mounted by means of a radially-extending flange (12). The coil for interaction with the magnet is positioned in an annular air gap between the polepiece (14) and the housing (II). The coil is wound on a coil holder (8) which is itself mounted on the piston (6) by way of a radially-extending flange (7).