July 10 - 16, 2011: Issue 14
Due to a lot of interest in the items people collect we will begin a Collector's Corner from the next issue and alternate between the many people who have old or unusual objects with history associated with them. This week we bring you two more objects from Trevor's Museum, a 'Silent Cop' and a Milk Seperator.
(Engineering / Automotive Engineering) Austral informal a small hemispherical traffic marker at an intersection.
Trevor tells us that up until a couple of years ago these silent cops, or traffic domes, were still installed at Brookvale.
They are painted a bright yellow with cat's eyes arund them, that light up when refelcting any source of illumination. Installed in around 1902 on most Sydney roads, they served to aid the flow of traffic at intersections. With the increased use of motorcycles though, they became a hazard, catching the foot pedals as these vehicles turned.
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The centrifugal separator was first manufactured by Gustaf de Laval, making it possible to separate cream from milk faster and more easily, without having to let the milk sit for a time, and risk it turning sour. Possibly because Gustaf de Laval manufactured the first cream separators,many people credit the invention to de Laval. However, many patents appear before his, all of them labelled as 'improvements'. One of the first specifically for cream separation was patented by W. C. L. Lefeldt and C. G. O. Lentsch.
The original centrifugal separators were hand-cranked (as the one on Trevor's Museum is; Circa Approx. 1880). When spun, the heavier milk is pulled outward against the walls of the separator and the cream, which is lighter, collects in the middle. The cream and milk then flow out of separate spouts.