An improved apparatus for determining the co-efficient of expansion of solids

摘要

424,017. Linear-dimension gauges. GEORGE, Ltd., W. & J., and BOUGH, F. P., 157, Great Charles Street, Birmingham. Sept. 21, 1933, No. 26038. [Class 106 (ii)] [See also Group XX] To determine the coefficient of expansion of a solid, the specimen bar is clamped between a pair of bars of a material such as " Invar " (Registered Trade Mark), and between the specimen bar and a clamping bar is arranged a roller, movement of which operates an indicator. The specimen 5 is clamped between two bars 6, each provided at one end with a knife edge 6a to engage the specimen. The other end of the specimen rests on a roller 7 resting in turn in a bed 6b fixed to the lower bar 6. The corresponding end of the upper bar is provided with a block 6c having grooved longitudinal edges on the under surface resting on a transverse roller 8 between this bar and the specimen. The roller 8 has at one end a counterweight 8a and at the other end is secured a vertical rod 9 also counterweighted at 9a. The upper end of the rod is provided with a vertical hole to receive a pin 11 on a counterweighted pointer 12, a second pin 13 of which rests in a similar hole in a vertical rod 14 fixed to the clamping bar. The bars 6 and 5 are held together by a clamp 17 and the whole placed on supports 19a in a tank 19 which is double-walled, the space between the walls being filled with powdered cork 20 &c. The tank is closed by a two-part cover with openings to allow passage of bars 9, 14 and thermometers 24. The tank is carried on a strip metal stand 28 and is provided with a plug 21 to allow exit of the heated liquid in the tank. The pointer 12 co-operates with a scale carried on an adjustable stand outside the apparatus.