Abstract: A system for periodically flushing accumulated sediment from hot water tanks including a drain valve controlled by an electric actuating means capable of rapid actuation of the valve from its normally closed position to a fully open position. The electric actuating means is electrically connected to a timing means, such as a time clock, for actuating periodic flush cycles. A flush cycle begins when the appropriate signal commands the actuating means to open the valve and ends upon closure of the valve. The invention contemplates that the duration of each flush cycle will depend on the water tank size, and that a series of flush cycles will provide optimized flushing of sediment from the tank.

Abstract: Apparatus for sensing the electrical conductivity of fluid wherein when electrodes of the apparatus are exposed to fluid a voltage is developed on a capacitor which voltage has a magnitude determined by the condition of the electrical conductivity of the fluid to which the electrodes are exposed. A portion of the developed voltage is obtained, such as by means of a voltage divider connected across the capacitor, and this voltage portion is compared by means of a voltage comparator to a reference voltage. When the comparison indicates a predetermined relationship, for example equality, between the developed voltage portion and the reference voltage, a signal is produced which can be utilized to operate a load. In particular, the signal can operate a semiconductor controlled rectifier to complete a discharge path from the capacitor to the load. The load can be an electro explosive device included in a release mechanism for uncoupling a parachute canopy from its load upon landing in water.