Abstract: A solenoid operated directional valve with a valve body provided with a bore that has axially spaced annuli, a mounted surface with ports arranged in a pattern of standard configuration, and ducts extending from the ports to the annuli to provide passageways for flow of fluid, and a spool mounted for movement axially in said bore for controlling flow of fluid through said passageways, the passageways being formed in a unique manner in said body so that a minimum pressure drop occurs in the fluid flowing through each passageway.

Abstract: Apparatus for venting a sealed holding tank of a portable toilet to equalize the atmosphere and tank pressures before opening and closing the inlet port of the holding tank, said holding tank including a valve assembly for opening and closing the inlet port of the tank, and a vent port means in the tank associated with the valve assembly so that when the valve assembly is moved toward its open position, the vent means will be opened immediately prior to opening of the inlet port and when the valve assembly is moved toward its closed position, the vent port will be closed immediately after closing of the inlet port.