GB595000A - Improvements in or relating to recording apparatus - Google Patents

Abstract

595,000. Vacuum gauges ; recording- apparatus. RINGROSE, H. T. Sept. 4, 1944, No. 16782. [Classes 106 (ii) and 106 (iv)] An apparatus for recording conditions of vacuum comprises a driven recording disc or chart and a pivotally balanced indicator arm, the pointer of which is brought into contact, with the disc to mark it, at regular intervals of time and synchronously with the creation of the vacuum to be measured, by energizing an electromagnet. The apparatus may be connected to a porous pot in which a vacuum is created periodically by acting on a sample of the atmosphere by heat from an electric filament or by a chemical absorbent in order to detect the presence of certain gases or vapours by the resulting change of pressure. The indicator arm 3 is balanced by means of a counterweight 4 and a hair spring and is connected to a diaphragm 16 by means of adjustable levers. The diaphragm may also be adjusted by a screw 30 to set the zero. The electromagnet operates an arm 9 to bring the point of the indicator arm into contact with an inked ribbon, which may be driven to avoid local wear, and so to mark a clockwork-driven disc 2. Contacts, periodically made and broken by the clockwork motor, energize the filament contained in the porous pot (not shown) and then energize the electromagnet so that the drop in pressure in the porous pot, which is connected by a tube to the diaphragm, is recorded. A capillary tube leading into a vessel containing liquid allows pressure greater than that of the atmosphere to be released. This tube and container may be transparent and have an illuminated scale to afford an additional indication of the vacuum.