GB1000152A - Improvements in or relating to apparatus for studying rheological behaviour of plastic lubricants - Google Patents

Abstract

1,000,152. Studying plastic lubricants. HOUILLERES DE BASSIN D'AQUITAINE, and G. CUEYE. Nov. 13,1961 [Nov.16, 1960], No. 40556/61. Drawings to Specification. Heading G1N. In an arrangement for studying the behaviour of plastic lubricants one element of a bearing lubricated by calibrated measures of the lubricant under test is driven at a predetermined speed or series of speeds by a D.C. motor the armature current of which is measured by measuring the potential across a shunt as an indication of the drag torque of the bearing. The bearing is housed in a chamber the temperature of which is controlled by air conditioning plant to be held constant at any temperature between -20‹C.to 180‹C. or to follow a programme, and the torques, lubricant temperature and test chamber temperatures are continually sequentially recorded on the same recording tape through a selector switch, the drive of which is synchronised with the tape. The motor is coupled to the bearing via a clutch and drives also a tachometer generator, its speed is regulated by adjustment of the D.C. bias on a thyratron through which the armature current is supplied, the tachometer output being also applied to the thyratron to hold the speed constant. Ward Leonard or variable inductor control may be used. In a servomotor arrangement for controlling the temperature and for providing an indication thereof described with reference to Fig. 14 (not shown), cam operated contacts control the supply of hot or cold air obtained by passing the fan output over heater or a refrigerator. For the programming of temperature, the thermocouple voltage is opposed by a reference voltage corresponding to the desired temperature obtained from a slide wire by a mechanical cam arrangement. The manner of calibration is described and changes of torque with speed and temperature are described with reference to Figs. 19a-19d.