Improvements in or relating to beckmann thermometers

摘要

667,790. Thermometers. ELLIOTT, Ltd., H. J. July 4, 1950 [Aug. 16, 1949], No. 21317/49. Class 97 (iii). In a Beckmann thermometer, the reservoir for receiving excess liquid detached from the main column instead of being bent with consecutive U-formations, as is usual, comprises a rectilinear tube 10 in prolongation of the main column 12 and communicating with it through the intermediary of a droplet splint 14. To set the thermometer it is inverted until the desired amount of liquid has passed through the droplet splint 14. It is then turned on its side with the auxiliary reservoir 10 lower than the main reservoir (not shown) and given a sharp tap, whereby the liquid in the reservoir. 10 separates from the droplet splint and runs through a narrowing 15. On return of the thermometer to the upright position the droplet splint empties into the main column and the liquid in the auxiliary reservoir falls and rests on the now empty droplet splint, the cross-section of the orifice therein being so chosen as to support a column of liquid of the desired height. For a mercury column of 1 inch in the auxiliary reservoir, the cross-section of the orifice should be 0.0395-0.0625 sq. mm.; for greater heights the cross-section must be proportionally. decreased. The liquid in the reservoir may be returned to the main column by violent shaking or by centrifugal action. The internal diameter of the auxiliary reservoir is increased where it surrounds the droplet splint, and this enlarged part is provided with a central indentation so that mercury cannot crash against the joint of the droplet splint and the main column. Instead of being formed as shown, the auxiliary reservoir may consist of a tube of large diameter with a top section of small bore; in this case an indentation may be provided in the large diameter portion just below its joint with the top section. The bore of the main column 12 is increased to form a cavity 16 just below the droplet splint. An auxiliary scale 11 is provided behind the reservoir 10.