A welding system and a method of control. The welding system may include a weld gun that may have an induction coil and a guide sleeve. The induction coil may heat a welding electrode in the weld gun. The guide sleeve may inhibit the welding electrode from engaging the induction coil.

A powder bed fusion apparatus includes a build platform movable in a build sleeve, the build platform for supporting a bed of metal powder, a powder layer formation device for forming layers of metal powder to form the bed, a scanner for directing an energy beam to selected regions of each layer to consolidate the metal powder and a radio-wave generator arranged to surround the metal powder and generate radio waves to heat the metal powder that forms the bed.

A powder bed fusion apparatus includes a build platform movable in a build sleeve, the build platform for supporting a bed of metal powder, a powder layer formation device for forming layers of metal powder to form the bed, a scanner for directing an energy beam to selected regions of each layer to consolidate the metal powder and a radio-wave generator arranged to surround the metal powder and generate radio waves to heat the metal powder that forms the bed.

A plastic tube sealing device includes a clamp which has a pair of jaws that can move relative to each other for inserting and crimping a plastic tube, the jaws containing high-frequency (HF) jaw electrodes, and includes an electrical HF power supply circuit including an HF generator and the HF jaw electrodes. The plastic tube sealing device further includes an impedance control device (9) for acting towards maintaining an impedance of the HF power supply circuit constant during a respective welding operation by correspondingly controlling the variable impedance HF resonant circuit. For this purpose, the HF generator includes a variable impedance HF resonant circuit with a capacitor unit and a coil unit, and includes the jaw electrodes, wherein the inductance of the coil unit and/or the ohmic resistance of the HF resonant circuit is/are variably adjustable and/or wherein the capacitance of the capacitor unit is variably adjustable and the capacitor unit has an electrically controllable capacitance diode or at least one movable capacitance-altering capacitor electrode arranged in the clamp.

A plastic tube sealing device includes a clamp which has a pair of jaws that can move relative to each other for inserting and crimping a plastic tube, the jaws containing high-frequency (HF) jaw electrodes, and includes an electrical HF power supply circuit including an HF generator and the HF jaw electrodes. The plastic tube sealing device further includes an impedance control device (9) for acting towards maintaining an impedance of the HF power supply circuit constant during a respective welding operation by correspondingly controlling the variable impedance HF resonant circuit. For this purpose, the HF generator includes a variable impedance HF resonant circuit with a capacitor unit and a coil unit, and includes the jaw electrodes, wherein the inductance of the coil unit and/or the ohmic resistance of the HF resonant circuit is/are variably adjustable and/or wherein the capacitance of the capacitor unit is variably adjustable and the capacitor unit has an electrically controllable capacitance diode or at least one movable capacitance-altering capacitor electrode arranged in the clamp.

A thawing method for a thawing device includes: generating a radio frequency signal; acquiring the radio frequency signal; an upper electrode plate and a lower electrode plate of the thawing chamber generating, according to the radio frequency signal, radio frequency waves having a corresponding frequency in a thawing chamber and thawing an object to be processed, obtaining voltages and currents of the incident wave signal and reflected wave signal, and determining a thawing progress of the object to be processed.

A thawing method for a thawing device includes: generating a radio frequency signal; acquiring the radio frequency signal; an upper electrode plate and a lower electrode plate of the thawing chamber generating, according to the radio frequency signal, radio frequency waves having a corresponding frequency in a thawing chamber and thawing an object to be processed, obtaining voltages and currents of the incident wave signal and reflected wave signal, and determining a thawing progress of the object to be processed.

An apparatus and method for electromagnetic heating of a hydrocarbon formation. The method involves providing electrical power to at least one electromagnetic wave generator for generating high frequency alternating current; using the electromagnetic wave generator to generate high frequency alternating current; using at least one pipe to define at least one of at least two transmission line conductors; coupling the transmission line conductors to the electromagnetic wave generator; and applying the high frequency alternating current to excite the transmission line conductors. The excitation of the transmission line conductors can propagate an electromagnetic wave within the hydrocarbon formation. In some embodiments, the method further comprises determining that a hydrocarbon formation between the transmission line conductors is at least substantially desiccated; and applying a radiofrequency electromagnetic current to excite the transmission line conductors. The radiofrequency electromagnetic current radiates to a hydrocarbon formation surrounding the transmission line conductors.

An apparatus and method for electromagnetic heating of a hydrocarbon formation. The method involves providing electrical power to at least one electromagnetic wave generator for generating high frequency alternating current; using the electromagnetic wave generator to generate high frequency alternating current; using at least one pipe to define at least one of at least two transmission line conductors; coupling the transmission line conductors to the electromagnetic wave generator; and applying the high frequency alternating current to excite the transmission line conductors. The excitation of the transmission line conductors can propagate an electromagnetic wave within the hydrocarbon formation. In some embodiments, the method further comprises determining that a hydrocarbon formation between the transmission line conductors is at least substantially desiccated; and applying a radiofrequency electromagnetic current to excite the transmission line conductors. The radiofrequency electromagnetic current radiates to a hydrocarbon formation surrounding the transmission line conductors.

A control circuitry (11) comprises an adjustable capacitor (C1), and a bias source (111) configured to apply a bias voltage (V2) to said adjustable capacitor (C1) to adjust a capacitance value of the adjustable capacitor (C1). Such a control circuitry may for example be part of a sealing device (1) to seal a medical tubing (2), the sealing device (1) comprising a receptacle (100) to receive said medical tubing (2), the receptacle (100) comprising an electrode arrangement for causing a heat action on the tubing (2).