Abstract: An source and load isolating device that will permit a two-wire distribution system to transmit additional signals on the same two wires that were used to supply current to electrical loads. The system simultaneously permits the status of all electrical loads to be individually monitored. Source line isolators (SLI) are used to present a high impedance between the source and line, and line load isolators (LLI) are used to present a high impedance between the line and load thereby isolating both from the two wire distribution system. Isolation timing synchronizers (ITS) coordinate the timing period of the SLI and LLI high/low impedance devices and provide timing signals for the communication or monitoring equipment. During the time the lines are used for a second signal, the electrical load is completely isolated from all other electrical interferences and their status is easily measured.

Abstract: A coolant recirculating system permits water from a municipal source to be circulated continuously in a dry cleaning plant in order to perform necessary cooling and condensing operations. The water is permitted to be dumped from the closed system only upon exceeding a temperature at which its cooling function has reduced efficiency. An additional benefit of the inventive closed circulating coolant loop is that the preheated water may be employed to supply a boiler in the dry cleaning plant and also that the loop water may be utilized in the lavatory facilities of the dry cleaning plant and in the laundry facilities of such dry cleaning plant.