The invention provides a sensing device that can be incorporated in a construction element for a toy construction set to allow new use of construction elements, for instance tracking the construction process. Sensing device comprises a carrier comprising a top surface provided with a series of top coils, a bottom surface with a series of bottom coils at a distance from said top coils, the sensing device further comprising a data processor functionally coupled with a memory for storing a status, said data processor comprises a computer program which controls and reads currents through each of said top and bottom coils and storing them in memory, thereby tracking status for each of said top and bottom coils.

A system and a method for liquefaction of gases which are utilized in their liquid state as refrigerants in applications that require low temperatures, throughout various pressure ranges, from slightly above atmospheric pressures to pressures near the critical point. The system and method are based on closed-cycle cryocoolers and utilize the thermodynamic properties of the gas to achieve optimal liquefaction rates.

Systems and methods disclosed herein relate to a cryogenic refrigeration system which may use a compression based cryocooler or liquid nitrogen pre-cool to cool a medium to 80K, and may in conjunction with a magnetic refrigeration system operating in the sub-80K temperature regime to provide cooling to a medium to temperatures below 80K. In some embodiments, the disclosed system may be useful for cooling on the order of about 3 kg/day to about 300 kg/day of hydrogen gas to liquid form, with higher efficiency than a standard vapor compression based system. This higher efficiency may make the system a more attractive candidate for use in cryogenic cooling applications.

Method for liquefying a gas (12) to be processed comprising at least 50% by volume of methane, comprising the following steps: purification of the gas to be processed, precooling of the purified gas (22) to a temperature less than or equal to 15 C. by heat exchange with a precooling refrigeration cycle (40), liquefaction of the precooled gas (26), in a liquefaction unit (30), into a liquid stream (32), with subcooling less than or equal to 5 C., the liquefaction unit including a Stirling refrigeration cycle (50) distinct from the precooling refrigeration cycle, this cycle using a first refrigerant (42) precooled by a precooling refrigeration cycle (40) distinct from a Stirling cycle, subcooling of the liquid stream, and expansion of the subcooled liquid stream (36) to obtain a liquefied gas (14).

An active gas regenerative refrigerator includes a plurality of compressor-expander units, each having a hermetic cylinder with a drive piston configured to be driven reciprocally therein, and a quantity of working fluid in each end of the cylinder. A piston seal in a central portion of the cylinder prevents passage of the working fluid between ends of the cylinder. Movement of the piston to a first extreme results in radial compression of one of the quantities of working fluid in a cylindrical gap formed between one end of the piston and an inner surface of the cylinder, while the other quantity is expanded in the opposite end of the cylinder. The piston includes a plurality of magnets arranged in pairs, with magnets of each pair positioned with like-poles facing each other. A piston drive is configured to couple with transverse magnetic flux regions formed by the magnets.

A low-temperature device for separating and purifying gas based on a small-sized low-temperature refrigerating machine includes a primary, secondary and quaternary heat exchanger, at least one small-sized low-temperature refrigerating machine, and at least one liquid collecting tank. The small-sized low-temperature refrigerating machine includes a first cold head and a second cold head, the secondary heat exchanger is provided on the first cold head to form a primary cold head heat exchanger, the quaternary heat exchanger is provided on the second cold head to form a secondary cold head heat exchanger, a mixed gas outlet is connected to an inlet of the primary cold head heat exchanger. By using primary and secondary cold heads of the small-sized low-temperature refrigerating machine as cold sources, gases having different condensing temperature are liquefied and solidified separately, and two or more gases can be separated and purified at a lower cost.

An active gas regenerative refrigerator includes a plurality of compressor-expander units, each having a hermetic cylinder with a drive piston configured to be driven reciprocally therein, and a quantity of working fluid in each end of the cylinder. A piston seal in a central portion of the cylinder prevents passage of the working fluid between ends of the cylinder. Movement of the piston to a first extreme results in radial compression of one of the quantities of working fluid in a cylindrical gap formed between one end of the piston and an inner surface of the cylinder, while the other quantity is expanded in the opposite end of the cylinder. The piston includes a plurality of magnets arranged in pairs, with magnets of each pair positioned with like-poles facing each other. A piston drive is configured to couple with transverse magnetic flux regions formed by the magnets.

Process and apparatus for producing pressurized gaseous nitrogen by cryogenic separation of air. The distillation column system includes a high pressure column, a medium pressure column, a main condenser and top condenser both being condenser-evaporators. Compressed and purified feed air is cooled in a heat exchanger and introduced to the distillation system. A gaseous nitrogen stream from the high pressure column is condensed in the main condenser. Bottom liquid of the medium pressure column is evaporated and gaseous nitrogen from the medium pressure column is condensed in the top condenser. Liquid nitrogen from the medium pressure column is pressurized and introduced to the high pressure column. A second gaseous nitrogen stream from the high pressure column is recovered as pressurized gaseous nitrogen product. A portion of the compressed and purified feed air is work-expanded and then warmed in the main heat exchanger.

Disclosed is a small-scale hydrogen liquefaction system using cryocoolers. The system includes: a pre-cooling heat exchanger for pre-cooling gaseous hydrogen using liquid nitrogen; a first cryocooler that primarily cools the gaseous hydrogen, pre-cooled by the pre-cooling heat exchanger; a heat exchanger attached to a cold head of the first-cryocooler; an n-th cryocooler (wherein n is a natural number equal to or greater than two) that is connected in series with the first cryocooler and cools the gaseous hydrogen, primarily cooled by the first cryocooler, to a liquefaction temperature of 20.3 K; a condensation plate arranged to be in contact with the n-th cryocooler to liquefy the gaseous hydrogen, cooled to the temperature of 20.3 K by the n-th cryocooler; and a low-temperature chamber providing an accommodation space to accommodate the pre-cooling heat exchanger, the first cryocooler, and the n-th cryocooler.

A liquefier includes a Dewar having a storage portion and a neck portion extending therefrom. A hermetically isolated liquefaction chamber is disposed within the neck of the Dewar. One or more control components including a temperature and pressure sensor are coupled to a CPU and disposed within the liquefaction chamber for dynamic control of liquefaction conditions. A gas flow control is coupled to the CPU for regulating an input gas flow into the liquefaction chamber. A volume surrounding the liquefaction chamber may be adapted to provide a counter-flow heat exchange. These and other features provide improved liquefaction efficiency among other benefits.