Abstract: An automatic cylinder profiling gage system comprises a measuring head adapted to fit into a cylinder and including a number of transducers associated therewith, each transducer generating a positional signal corresponding to the distance from the head to the interior wall. The gage further includes a processor adapted to receive the signals, compare them with stored data indicative of the profile of an ideal cylinder so as to determine deviation therefrom. The system is further adapted to provide a visual display of data relating to cylinder profile. The gage system may further include calibration means as well as particular computer programs for processing information generated thereby to provide statistical or other information.

Abstract: A gas furnace employs an exhaust flue damper driven by an electric motor equipped with position indicating switches. A gas flow detector switch supported in the gas line has a vertical passage and a valve member gravity biased into a rest position in which it blocks gas flow through the passage. Fuel flow through the line creates a differential pressure on the valve, raising it above the rest position. Circuitry interconnecting the damper drive and position indicating switches and the gas flow switch with the furnace thermostat and the gas line control valve, positions the damper in a closed position when there is no gas flow to the furnace and in an open position otherwise and prevents energization of the gas flow valve when the damper is closed.