Abstract: A PC board containing electronic components of a normally closed switch is enclosed in a case and connects to a circuit using two wires. Electrically conductive sensor-probe pins extend from the PC board and are positioned for detecting liquids at various levels within drains, drain pans, tanks, reservoirs and pipes of various dimensions. An optional remote probe, having a pair of electrically conductive sensor probe pins, connects to the PC board and is adapted for positioning at a location that is separated from the enclosed case, such as in an auxiliary drain pan of an HVAC system. The normally closed switch is actuated to an open state upon a rising liquid level contacting the tips of the sensor probe pins. Actuation of the switch to the open state changes the status of the circuit from a normally closed circuit condition to an open circuit condition, thereby interrupting operation of a system (e.g. HVAC) on the circuit.

Abstract: A disposable trash container has a lining made of plastic or other material forming a bottom and sides, and an expandable spring loaded frame structure connecting between a base at the bottom of the lining and a top hoop near a closable top opening of the lining. One or more clasps hold the lining and frame structure collapsed flat near the base in a low profile state for packaging. When ready for use, the clasp(s) is operated to release the spring loaded frame structure, thereby causing the trash container to open as the frame structure expands and the top hoop moves upwardly and away from the base. The top opening of the lining may be provided with a drawstring or other means to close the trash container prior to disposal.

Abstract: An alarm device that connects to a circuit using two wires and is actuated when a switch changes the status of the circuit from a normally closed circuit condition to open circuit condition. The alarm device includes a PC board with an electronic buzzer, an electronic signal transmitter and/or a visual indicator, such as a flashing LED, all of which may be enclosed within a case. The circuitry of the alarm device is non-polarized, thereby allowing the two wires to be connected to either terminal connection point in the circuit.

Abstract: A safety switch prevents overflow of condensate that collects in the drain pan of an air-cooling system. The overflow safety switch attaches to the condensate drainage system and is electrically connected to a circuit of the air-cooling system, a power circuit, a control circuit and/or an alarm circuit. The switch includes a tube that extends within the condensate drain pan or any other water conducting point in the condensate drainage system. A reed switch is sealed within the tube and a float containing a magnet is moveably supported on the exterior of the tube. The float ascends or descends in response to the level of the liquid condensate within the drain pan. As the float moves relative to the tube, the magnet causes the reed switch to open, thereby interrupting operation of the air-cooling system and/or actuating the alarm circuit.