Abstract: Methods of and apparatus for cleaning coal in which halogenated hydrocarbons are used as parting liquids. Various novel techniques, components, and combinations thereof are employed to maximize efficiency; to minimize costs and adverse environmental impacts; to make it possible to recover coal of a character which has heretofore been economically unrecoverable; to produce a superior product; and to reach other worthwhile goals.

Abstract: A housing, a first elongated generally cylindrical member fixed to the housing and having an open end which is adapted to be in open communication with the interior of the sealed transformer casing; this first member also has at least a portion of its length composed of transparent material for viewing the interior. Means, such as a float, are contained in the first cylindrical member for providing a visual indication of the gas emission levels. Additional means are coupled to and communicate with the first cylindrical member for measuring gas emission levels in the transformer and for measuring variations in the internal pressure of the transformer casing. A second generally cylindrical member is fixed to the housing and has one end adapted to extend into the sealed transformer casing. This second member includes means, such as temperature sensors, for detecting changes in the temperature of the dielectric in the transformer casing.