Improvements in calculating devices for solving equations between a number of variables such as calculating the consumption of gas

摘要

211,669. Forshaw, A. Jan. 26, 1923. Slide-rules more particularly intended for solving prublems in connection with gas lighting involving such data as pressure, rate of consumption, specific gravity and size of jet, comprises three coaxial discs A, B, D, the disc D being disposed between discs A and B and having a projection 1 passing through an arcuate slot in disc B and provided with an enlargement extending beyond its periphery. Disc A bears a scale of pressures and has three reading apertures to enable one or other of three concentric scales of jet dimensions on disc D to be read. Disc B is provided with a scale of consumption in cubic feet per hour and also a scale of specific gravities with which co-operates an index mark G on the enlargement. A loose arm 3 enables the disc D to be set relatively to the consumption scale on disc B for conditions involving orifice coefficients other than that for which the scales are constructed.