Abstract: An assembly of a display panel and a mounting base for a plurality of light-emitting elements. The mounting base is adjacent to one side of the display panel, and the display panel has a plurality of light-transmitting apertures, holes or openings representing at least two different fluid flow paths and specific fluid devices, such as valves and fluid containing cylinders. A microprocessor is used to control the operation of voltage sources coupled to the light-emitting elements so that, by selectively actuating a first set of light-emitting elements, a visual representation of a first fluid flow path can be provided to indicate the flow of a first gas from one location to another. Alternately, the assembly can be operated such that a second fluid flow path can be visually represented while the light elements of the first path are deactuated.

Abstract: An assembly for collecting and disposing of waste solvents in a manner to meet safety requirements of municipalities. The assembly includes a waste tank and an open-top container for receiving and supporting the waste tank. The container has a greater internal volume that does the waste tank so that, when the waste tank is in the container, a space surrounds the waste tank. Such space is adapted to receive and trap any leakage or overflow of the solvent from the waste tank during use of the assembly. The waste tank has a first port for receiving waste solvent and a second port for allowing the waste solvent to be pumped out of the waste tank. Liquid level sensors are provided on the waste tank for sensing the solvent therein at different levels. The container has brackets for positioning the waste tank on the bottom of the container, and the container has casters to allow the assembly to be easily shifted from place to place.