Abstract: Heat transfer fluids which can be used over a broad range of temperatures such as from ?125° C. to +175° C. are disclosed. These transfer fluids consist essentially of a mixture of two either narrowly defined structurally non-identical alkyl- or polyalkyl-benzene components or a mixture of a narrowly defined aromatic alkyl- or polyalkyl-benzene component and an aliphatic hydrocarbons component. The level of the various ingredients is such that the transfer fluids exhibit a cloud point below ?100° C., a vapor pressure at +175° C. below 827 kPa and a viscosity, measured at the cloud point temperature +10° C., below 400 cP.

Abstract: Heat transfer fluids which can be used over a broad range of temperatures such as from 175° C. to ?145° C. are disclosed. The heat transfer fluids consist essentially of a mixture of at least two structurally non-identical cycloalkane-alkyl or -polyalkyl compounds, or a mixture of at least two structurally non-identical aliphatic hydrocarbons, or a mixture of a cycloalkane-alkyl or -polyalkyl compound and an aliphatic hydrocarbon. The individual components are present at levels such as to confer to the fluid composition a cloud point below ?100° C., a vapor pressure at +175° C. below 1300 kPa, and a viscosity, measured at the cloud point temperature +10° C., below 400 cP.

Abstract: A circuit breaker has a set of remotely controllable secondary contacts connected in series with the main contacts which provide overcurrent protection. The secondary contacts are opened and closed by a latching solenoid having a close coil and an open coil which are separately connected to switched terminals of a first switch. A voltage source, which may be ac, dc or pulsed, is connected to the common terminal of the first switch through a rectifier. The first switch is coupled to the plunger of the latching solenoid which opens and closes the set of secondary contacts and enables the coil which operates the set of secondary contacts to the opposite state. Energization of the enabled coil is completed by additional, remotely located switches connected between each coil and ground. A status line connected to one of the switched terminals of the first switch is energized when the associated coil is enabled to indicate the open/close status of the set of secondary contacts.