GB910914A - Pour point apparatus and process for using same - Google Patents

Abstract

910,914. Determining pour points. ESSO RESEARCH & ENGINEERING CO. Feb. 10, 1961 [March 8, 1960], No. 5022/61. Class 97 (3). [Also in Group XL (b)] An arrangement for determining the pour point of oils, i.e. the minimum temperature at which the oil is mobile, comprises a container for the oil and rotatably mounted near its top on a rigid and stationary horizontal pivot axis so as to be capable of rotating in a vertical plane, a light source positioned to permit a beam to strike the surface of the oil within the container, a photo-electric sensing element positioned to change its electrical signal output upon angular movement of the oil surface with respect to the container, whilst the oil is mobile, a temperature sensing means immersed in the oil within the container, and means for periodically and partially swinging the container about the horizontal pivot. The arrangement includes means for gradually reducing the temperature of the oil to a value at which it is no longer mobile, so that during the rocking motion there is no change in the electrical signal from the photoelectric sensing element. As shown in Fig. 1, the oil 5 is in a container 2 mounted in a casing pivoted at 4, and carrying an arm 12 engaged between a biasing spring 16 and an eccentric cam 15 rotated at one revolution per minute. The container has a closure member 3 carrying a thermocouple member 7 and formed with channels for a light source 8 and a photo-cell 11. Normally, i.e with the container in the position shown, no light from the source 8 reaches the photo-cell 11, but with the oil in liquid form, the rocking of the container changes the relative position of the surface 6 so that some light is reflected to the cell, until with the oil temperature sufficiently reduced, the oil surface remains invariable with respect to the container and no light reaches the cell. In the circuit arrangement, Fig. 3, with contacts 18, 19 closed, a capacitor 22 is charged and provides anode voltage for a thyratron 23. If the cell 11 receives light reflected from the oil surface, a valve 28, operating as a cathode follower, controls a valve 29 to apply positive voltage to render the thyratron 23 conducting to effect discharge of the capacitor 22. If no light reaches the cell 11, the thyratron remains non-conducting, and the closure of contacts 18, 20 effects discharge of the capacitor 22 through relay 30 which operates, locks up over actuated contacts 31 and 32 and over contacts 34, 35 actuates a control circuit 36 to hold a recorder 37 at its last reading which is the pour point of the oil sample. Other dispositions of the light source in relation to the oil surface and the photo-cell are described in connection with the diagrammatic arrangements of Fig. 2 (A, B, D, E, F, G) (not shown), the arrangement of Fig. 2C (not shown) being regarded as similar to the embodiment of Fig. 1. Two of the diagrammatic arrangements, Fig. 2 (F, G), may be used to detect the cloud point in addition to the pour point for the sample of oil in the container.