Abstract: A constant illumination level control system for continuously adjusting the evel of artificial illumination in an area of controlled lighting to complement available natural illumination. A photocell sensor in combination with an input amplifier generates a voltage representative of the illumination level in the area of controlled lighting. This illumination level voltage is compared by a comparator with a reference voltage, a non-zero difference voltage output from the comparator being indicative of a change in the illumination level from a desired, preset level. The output from the comparator is applied to a solid state dimmer circuit which, by controlling the gating of a triac, regulates the electrical energy input to the artificial lighting system. In response to a non-zero difference voltage output from the comparator, the solid state dimmer circuit, in combination with the triac, adjusts the artificial illumination output to reestablish the desired, preset level of total illumination.

Abstract: A commutating or distributing valve for timing and distributing high prese seawater to a number of individual pistons in a multi-piston hydraulic motor using seawater under pressure as a motivating fluid.