Abstract: A system for transmitting power over a direct voltage network. A first power station connects one alternating voltage network to the direct voltage network. The first power station includes a converter for bidirectionally transferring power between the direct voltage network and the alternating voltage network. The converter maintains constant value of voltage on the network, or operates in a second alternative mode of controlling constant current between the alternating voltage network and the direct voltage network. When the voltage on the direct voltage network drops below a reference value, a second power station connected to the direct voltage network and to a remaining alternating voltage network takes over the voltage regulation function. The second power station prior to taking over the voltage regulating friction was in a current regulating function.

Abstract: A hot-isostatic press adapted for rapid cooling of the hot zone after completed pressing and sintering of the material includes a pressure vessel, end closures, and a hot zone surrounded by thermal barriers. Between the thermal barriers and the pressure vessel with end closures there are colder spaces. At least one connection, located in the lower part of the thermal barrier and provided with a valve between the space next to the pressure vessel and the space below the bottom thermal barrier, is provided with an externally controllable valve. In the upper part of the thermal barrier there is an opening with a relatively large cross section and a valve is provided for the opening, which comprises a heat-insulated portion.