GB190423363A - Improvements in Calculating Apparatus. - Google Patents

Abstract

23,363. Peard, O. L. Oct. 29. Slide rules.-Arrangements of slide rules with logarithmic scales are described for calculating the following quantities:- (1) Loss of heat in waste furnace gases expressed in percentage of normal coal, or British thermal units, from the temperature of and percentage of carbon dioxide in the flue gases ; (2) heat transmitted to water and steam, or thermal efficiency from feedwater temperature and weight of water evaporated per pound of coal burnt; (3) kilowatts from amperes and volts. Fig. 4 shows a section through a circular form in which one datum scale is on the disc A attached to the upper rotatable glass cover E, and the other upon the upper side B of a ring attached to the lower cover E'. Below this ring is the result scale D, which is read against a pointer C upon the central disc. In a modification, all the scales may be read from one side, the scales B, D being upon the same side and the reading-point moving with the scale A. This form may be arranged for a double calculator, as in Fig. 8, where the central disc F turns with the top-plate E and rim J, while the ring G moves with the lower ring J<1>, scales being provided both above and below. Fig. 10 shows a band arrangement for use when one of the datum scales is much shorter than the other, the long scale being placed on a band H, which also carries the result scale and is controlled by a hand-driven pulley G<1> and a tension pulley i, so as to display the quantities through suitable windows, one of which is marked for the second datum scale and the other has the reading-pointer. Alternatively, the long scales may be put on a drum, or upon a rod with the short scale and reading-point upon a slider.