Abstract: A machine management system improves flexibility in control of an apparatus and installation of an additional apparatus. A plurality of refrigerators sends operational information to a virtual machine constructor. The virtual machine constructor constructs virtual machines corresponding to the refrigerators using the received information, and holds the virtual machines therein. Each time the virtual machine constructor receives new information from the refrigerators, it updates the virtual machines. Controllers receive and hold virtual machines from the virtual machine constructor. The controllers cause one of the virtual machines to be selected and displayed in response to a user's request.

Abstract: A valve stem driving apparatus comprises a valve stem which has first and second ends, the second end being connected to a valve body. The valve stem is engaged with a stem nut. A distance measuring device is provided in an upper cover for the valve stem and measures a distance between the upper cover and the first end of the valve stem, so that wear rate of the valve stem and/or the stem nut is determined.

Abstract: Method and apparatus for diagnosing abnormality of an oil-filled electric apparatus is disclosed. Presence or absence of abnormality is determined by comparing contents of plural predetermined components contained in gas extracted from the oil of the electric apparatus with respective predetermined reference values. The type of abnormality is determined on the basis of at least one set of two specific components selected from the plural components.

Abstract: In an apparatus for detecting gas components in the oil in an oil-filled device, which comprises a gas-storing chamber being provided at an oil-filled device containing an insulating oil through a gas-permeating material capable of separating gas components from the insulating oil, a gas calibration tube being provided at the gas-storing chamber through a switch valve, and a gas chromatographic device connected to the gas calibration tube through the switch valve, any influence of gas components in a subatmospheric pressure is eliminated and exact concentrations of gas components are detected by providing at least one stirring mixer having at least one throttle perforation in a carrier gas passage for supplying the gas components from the gas calibration tube to the gas chromatographic device at the upstream side of a gas separation column of the gas chromatographic device, or by proving a circulation passage between the gas-storing chamber and the gas calibration tube, a valve capable of being exposed to the