Patent GB-642948-A (GB)
Title: A process and apparatus for the cooling of molten lubricating greases
Filed: 1947-05-02
Abstract: <PICT:0642948/III/1> <PICT:0642948/III/2> <PICT:0642948/III/3> <PICT:0642948/III/4> <PICT:0642948/III/5> <PICT:0642948/III/6> In the manufacture of lubricating grease the grease is fed in fluid condition on to a heat conductive moving surface in an amount to form a continuous thin layer on the surface and the grease layer on the surface is passed through a cooling zone while cooling gas is flowed through the zone to solidify the grease, a shearing stress being avoided.  The thickness of the grease layer may be about 0.1 inch to an inch and more particularly about p  0.2-0.4 inch.  As shown, molten grease is fed into a cooling apparatus and distributed uniformly over the surface of a horizontal endless steel belt 19, Figs. 3 and 6, by an inlet conduit 41, header 42 and distributing outlets 43.  An adjustable baffle 44, Figs. 2, 3 and 6, positioned between the outlets 43 and the exhaust stack 38, Fig. 6, of the sheet metal casing 10, Fig. 1, prevents too rapid cooling of the grease immediately after being fed, and permits the grease in hot liquid condition to spread out on the surface of the belt in a uniform layer.  A dam 45 of angular cross-section (Fig. 2), provided with oil-resistant synthetic rubber ends or surfaces where it is in contact with the grease, prevents the grease from flowing off the end of the belt. The belt 19, Fig. 6, is rotated in a clockwise direction and the cooled grease is removed from the belt by a scraper 46, Figs. 5 and 8, and is caught in the hopper 47 from which it is discharged through ports fitted with sliding covers 50 and 51 into either one of the tanks 48, 49 fitted with valves 52, pumps 53 and strainers 54, Fig. 6.  The belt 19 is trained over pulleys 17 and 18, the latter being belt <PICT:0642948/III/7> <PICT:0642948/III/8> <PICT:0642948/III/9> <PICT:0642948/III/10> <PICT:0642948/III/11> driven by a variable speed transmission and motor.  The belt is tensioned by the frame 24 urged by means of a weight 25.  The belt 19 is provided with a pair of strips, preferably of a synthetic rubber, 20 and 21, Fig. 3, which prevent the hot grease flowing off the edges of the belt.  The upper course of the belt is preferably supported on a number of U-shaped steel rods 29, Figs. 1 and 4, carried by the supporting frame members 30 and provided with level-adjusting nuts 31 and 32.  Cooling air is fed into the outlet end of the casing 12 from a pair of blowers 33 and 34, Fig. 6, which direct air along the upper and lower surfaces respectively of the upper run of the belt.  A baffle 35 within the casing directs the flow of air from the blower 33 substantially parallel with the upper run of the belt 19.  Two or more discharges leading into both sides of the casing at the grease outlet end (as at 36 and 37, Fig. 7) are provided from the lower blower.  The air is exhausted from the casing by the stack 38, Fig. 6, directly communicating with the upper portion of the casing at the grease inlet end, and provided with a pair of ducts 39 and 39a, Figs. 1 and 6, communicating with the casing below the upper course of the belt.  The lower course 19a of the belt may be supported on idler pulleys 40, Figs. 6 and 7, or on steel rods in the same manner as the upper course, and may be provided with means for supplying cooling medium through the casing.  In a modified form of the apparatus an intermediate pair of exhaust ducts 55 and 55a, Figs. 9 and 10, are provided at a point 56 located approximately one-third of the length of the casing from the hot end thereof, the casing 57 (corresponding with the casing 10 shown in Fig. 1) being thus divided into a "hot zone" A and a "cold zone" B.  The casing 57 is provided with adjustable baffles 58 and 58a, Figs. 9, 10 and 11, by means of which the relative amounts of air escaping from the casing through the pair of ducts 55 and 55a and the pair 39 and 39a respectively may be controlled.  In this manner the grease may be cooled more slowly during its passage through the "hot zone" A than during its subsequent travel through the "cold zone" B.  The invention is said to be suitable for the manufacture of hydrous and anhydrous sodium soap greases (including those containing crystallization inhibitors such as polymerized higher polyalkylene glycols), and lithium soap greases.  Examples are furnished of the manufacture of such greases. Specification 639,203 is referred to.