Abstract: Radio frequency power for melting, sealing and welding plastic tubing compressed between a pair of manually or automatically actuated electrically conducting jaws of a hand held or fixed base tubing sealer is regulated by a pulse width modulator controlling the duty cycle of applied constant voltage pulses. A predetermined change of impedance of the tubing during compression and melting is detected to regulate the power applied and to ensure a weld of predetermined physical parameters. On completion of the weld, a first timer is reset and a further weld may be made. In the event of impedance mismatch, a second timer inhibits further application of power and resetting of the first timer. The use of the pulse width modulator enhances conservation of power and accommodates portability of the tubing sealer through use of rechargeable batteries as the power source.

Abstract: A process for consolidating a composite material comprising the steps of forming a workpiece including a matrix interspersed with fibers, supporting the workpiece by an electrically conductive support, inductively heating the support and thereby conductively heating the workpiece, and applying pressure to the heated workpiece.

Abstract: Radio frequency power for melting, sealing and welding plastic tubing compressed between a pair of manually or automatically actuated electrically conducting jaws of a hand held or fixed base tubing sealer is regulated by a pulse width modulator controlling the duty cycle of applied constant voltage pulses. A predetermined change of impedance of the tubing during compression and melting is detected to regulate the power applied and to ensure a weld of predetermined physical parameters. On completion of the weld, a first timer is reset and a further weld may be made. In the event of impedance mismatch, a second timer inhibits further application of power and resetting of the first timer. The use of the pulse width modulator enhances conservation of power and accommodates portability of the tubing sealer through use of rechargeable batteries as the power source.

Abstract: A method of maintaining the housing of a reactor pressure vessel having: a reactor pressure vessel into which cooling water is introduced; a cylindrical housing which penetrates an end bracket of the reactor pressure vessel; and a circumferential weld for securing the intermediate portion of the housing to the reactor pressure vessel by welding, the method of maintaining a housing of a reactor pressure vessel comprising the steps of: remaining the cooling water in the reactor pressure vessel; preventing leakage of the cooling water in the reactor pressure vessel through the housing by sealing the housing; making the inside portion of the housing lower than the seal to be a hollow space of a gas atmosphere; heating a heat affected zone due to welding by using a heating device inserted into the hollow space from a lower portion so as to compressive-yield the inner surface of the housing in the heat affected portion upper than the circumferential weld and tensile-yield the outer surface; and cooling heated porti