A cryocooler includes a second-stage cooling stage, a second cylinder which includes the second-stage cooling stage on a terminal of the second-stage cylinder, a second-stage displacer which includes a magnetic regenerator material and is accommodated in the second-stage cylinder so as to be able to reciprocate in the second-stage cylinder, and a tubular magnetic shield which is installed on the second-stage cooling stage and extends along the second-stage cylinder outside the second-stage cylinder. The magnetic shield is formed of a normal conductor and a product of an electrical conductivity in a temperature range of 10 K (Kelvin) or less and a thickness of the tubular magnetic shield is 60 MS (Mega-Siemens) to 1980 MS.

A cryocooler includes an attachment flange including a refrigerant gas introduction port through which refrigerant gas is introduced into a recondensing chamber from an ambient temperature environment, and attachable to the recondensing chamber, and a cooling stage that is disposed inside the recondensing chamber when the attachment flange is attached to the recondensing chamber. The refrigerant gas introduction port is perpendicularly or obliquely oriented with respect to an axial direction of the cryocooler so that a refrigerant gas flow exiting the refrigerant gas introduction port deviates from the cooling stage.

A linear compressor according to the present disclosure may include a cylinder provided with at least one groove, a piston reciprocating within the cylinder, a motor configured to provide a driving force to move the piston within the cylinder, an inverter configured to perform a switching operation to transmit electric power to the motor, and a controller configured to receive temperature information from the electronic device and control the inverter to preheat the motor based on the received temperature information.

A cryocooler includes a motion conversion mechanism that converts rotating motion output by a motor into linear reciprocating motion of a displacer and includes a first component and a second component slidably connected to each other, a measuring instrument that is connected to the motor to output time-series data indicating power consumption of the motor or a current flowing through the motor, and a processing unit that detects abrasion of a sliding surface between a first component and a second component of the motion conversion mechanism on the basis of section data including an intake start timing or an exhaust start timing in the time-series data.

A method and apparatus for detecting the displacement amplitude of an armature of a linear motor or alternator that is drivingly coupled to a load or prime mover. The method and apparatus require only three inputs all derived from the input terminals of the linear motor or alternator: (1) the voltage measured across the linear motor terminals; (2) the current consumed by the linear motor; and (3) the phase between the voltage and current. The three inputs are sensed at the terminals of the linear motor or alternator and used to perform mathematical calculations in the microcomputer of a control system or controller. The mathematical calculations are based on equivalent circuits that are modifications of the equivalent circuit for the linear motor or alternator. The detected displacement amplitude can be used by a controller to limit the displacement amplitude of the armature to prevent collisions.

A method for increasing working gas flow rate through gas bearings of a free piston, gamma configured Stirling heat pump to avoid failure of the gas bearings while maintaining thermal cooling power. The Stirling heat pump lifts heat from a storage chamber and has pistons that are driven in reciprocation at an operating frequency by linear electric motors. A temperature control maintains a steady state storage chamber temperature by sensing storage chamber temperature and modulating piston amplitude. The invention comprises (a) driving the pistons with linear electric motors that are driven by a variable frequency, AC power source; (b) sensing the pistons' amplitude of reciprocation; and (c) if the sensed piston amplitude is less than a selected piston activation amplitude, increasing the frequency of the AC power source to increase the Stirling heat pump's operating frequency. That decreases thermal cooling power which causes the temperature control to increase piston amplitude.

A cryocooler is disclosed. The cryocooler may include a magnetic spring, a regenerator/displacer, a working fluid, and a cold finger configured to contain the working fluid in a closed system, and to contain the regenerator/displacer that is configured to travel linearly within the cold finger. The magnetic spring may provide a force to cause the regenerator/displacer to return to a center position during thermal cycle operation of the cryocooler. Additional systems and related methods are also provided.

A method and apparatus for detecting the displacement amplitude of an armature of a linear motor or alternator that is drivingly coupled to a load or prime mover. The method and apparatus require only three inputs all derived from the input terminals of the linear motor or alternator: (1) the voltage measured across the linear motor terminals; (2) the current consumed by the linear motor; and (3) the phase between the voltage and current. The three inputs are sensed at the terminals of the linear motor or alternator and used to perform mathematical calculations in the microcomputer of a control system or controller. The mathematical calculations are based on equivalent circuits that are modifications of the equivalent circuit for the linear motor or alternator. The detected displacement amplitude can be used by a controller to limit the displacement amplitude of the armature to prevent collisions.

A tubular reactor which acts as a combustor and heat exchanger is disclosed. Such reactor supplants a system with a combustor having a heat exchanger arranged around the combustor. The combined system includes a diffuser having an inlet for a fuel-and-air mixture and a plurality of holes defined in its surface through which the fuel-and-air mixture exits the diffuser and a plurality of tubes. First linear portions along the length of each tube are mutually parallel with a centerline of the first portions of the tubes displaced from the diffuser by a predetermined distance. Centerlines of the linear portions of adjacent tubes are displaced from each other by a predetermined gap. The fuel and air combust in the proximity of the first portion of the tubes for effective heat transfer to gases traveling through the tubes. Such a tubular reactor can be employed within a thermal-compression heat pump.

Provided is a linear compressor. The linear compressor includes a shell, a compressor body disposed in the shell, and a first support device coupled to a front portion of the compressor body in an axial direction to support the compressor body. The first support device may be disposed between an inner circumferential surface of the shell and the compressor body to support the compressor body in a radial direction.