GB661382A - Improvements in or relating to tide models - Google Patents

Abstract

661,382. Electric control systems. ROLFE, J. A. S., and BECKETT, A. H. May 20, 1949. [May 27, 1948] No. 14359. Class 40 (i). [Also in Group XV] In a model for investigating the effect of tides, the water level and rate of flow are independently controlled in accordance with a programme. As shown in Fig. 1, a model of a tidal channel is contained in a tank 1 the level of water in which is controlled by a motordriven valve controlling admission of water from a tank 15 and out-flow to another vessel 17. The rate of flow is controlled by a screw 7 driven by a reversible motor 8. Each motor is controlled by the output of a Wheatstone bridge of which two of the arms are formed by the resistances of liquid between a movable and two fixed electrodes in respective devices for measuring level or flow, the other two arms being formed by the respective resistances of liquid between fixed electrodes 22, Fig. 5, and a movable electrode 24 operated by a moving coil instrument controlled in accordance with the programme. A combined depth and flow meter 10 is shown in Fig. 6. The flow meter comprises a frame with staggered vanes 63 which is deflected by the water flow and moves an electrode 55 between fixed electrodes 54 in a central compartment of the float of the level meter. This float is carried adjustably on a counterweighted beam the position of which determines the position of an electrode 73 between electrodes 72 in another compartment. The programmes are recorded as curves on paper bands such as 40, Fig. 4, each of which co-operate in known manner with an interrupted light beam, a photo-cell 48 energizing an amplifier whose output is series connected to the mirror galvanometer 46, and the moving coil instrument shown in Fig. 5, so that as the band is traversed the light beam follows the curve, and the bridge is unbalanced to energize the appropriate motor, which adjusts the level or flow according to the programme, and rebalances the bridge.