Chemistry
Page 47
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as an ally of
Efficient Transport
FOR the paper that he read at the annual conference of the Scottish Road Passenger Transport Association, at Pitlochry, last week, Mr. E. R L. Fitzpayne, B.Sc., M.I.E.E., MI.Mech.E., general manager of Glasgow Corporation transport department, chose the rather unusual subject
of "Chemistry in Transport." .
The major work of the transport department's laboratory, said Mr. Fitzpayne, was the routine examination of coal, oil fuel, water, reclaimed lubricating oil, turbine, engine, and gear oils in service, bearing metals, aluminium alloys, corroded metals, flue and exhaust gases and so on. .
With the exception of one garage, at which there were 15 buses, the corporation's entire fleet of oilers, was running, he said, on a straight mineral oil, without any form of additive. The 15 vehicles were operating on heavy-duty lubricants containing antoxidant and detergent, and the engines so far examined appeared to be in rather cleaner condition than normal. But a longer period of test would be necessary, he said, before any definite conclusions could be reached.
Misleading Success
He mentioned this because, on a former test, with a certain brand of solvent-refined oil, the early indications of the condition of the sump oil from samples drawn, were very favourable, but later there was a spate of sticking piston rings.
Sampling difficulties prevented any great reliance from being placed on analyses of sump oil, said Mr. Fitzpayne, and the type and efficiency of oil filters greatly affected the results obtained. Experiments carried out on four engines showed that at the end of 4,000 miles' running, the free carbon and carbonaceous content of the four oils ranged from 1 to 2 per cent., but at the end of a further 4,000 miles. these figures had fallen to 0.5 and I per cent. respectively. The most reasonable explanation. said the speaker, was that finely divided carbon passed through a relatively clean filter, but the filter gradually clogged and the carbonaceous matter responsible for the clogging, to some extent trapped the finely divided carbon.
Oil Reclaimed
The 550 vehicles comprising the fleet used 40,000 gallons of engine oil every year, said Mr. Fitzpayne, and sumps were drained every 7,500 miles. The used oil was reclaimed in a StreamLine filter and returned to service.
The total quantity reclaimed every year was 6,000 gallons, and its viscosity was only a little lower than that of the original oil. A new scheme in connection with sump draining and oil replacement was, however, already well advanced, Under it, the filters would be removed from the engines, and the oil withdrawn from the sump by suction every night, or perhaps at longer periods.
The oil thus drawn off would be passed through a central oil-cleaning plant, so that all engines would, at alt times, be running on clean lubricant, free from moisture, sludee and abrasive particles. Improved crankshaft and bearing life and other advantages were logical expectations. In effect, an attempt would be made to adopt for bus engines the standard practice employed in the case of turbines and marine oil engines.
A way in which the laboratory was particularly useful was in sorting out extravagant claims made by oil, paint and brake-facing salesmen, said the speaker. The position of additives in the lubricating oil trade, he said, was more or less akin to that of synthetic resins in the varnish and paint industry. I4e mentioned that chloronaphthaxanthite, an organic compound, having a 15 per cent. sulphur and 33 per cent. chlorine content, was being used as an extreme-pressure additive in gear oils to give a high film-strength, such as was necessary in the case of the hypoid gear.
Lubricants for Flubs
The most suitable lubricant for roller-bearing hubs on buses had been found to be a hybrid grease containing both sodium and calcium soap, and having a medium consistency. The melting point was about 300 degrees F.
Mr. Fitzpaync mentioned that the oil fuel now used in the corporation's buses was a shale-oil product, and although differing slightly from the equivalent petroleum fraction, the differences were not sufficient to affect the running of the fleet.
Referring to the cleaning of the corporation's vehicles. Mr. Fitzpayne said that he thought it was essentially a woman's job. Experiments had been going on for some years with mechanical washing plants and the sneaker held the belief that Glasgow Corporation was the first British undertaking to develop the system.
New machines which it was proposed to install, were to be equipped with settling tanks, and would employ a cleanser instead of straight water, as at present. It was also hoped to develop a conveyor-belt system. so that buses could pass through the wash at a uniform speed.
The speaker dealt at some length with the technicalities of paints and varnishes, in the course of which he referred to accelerated weathering tests. These could be carried out in the laboratory by submitting sped men panels to the fading and ageing action of a hiehly actinic carbon-arc lamp, to be followed by the action of sulphur dioxide gas and steam in a suitable glass container.
Green Paint Turns Blue
Sulphur dioxide, which was a corrosive and reducing agent, had the effect of giving a bluish tint to green paint, an action which was most notable in industrial areas, as the sulphur dioxide in the atmosphere was a product of the combustion of coal.
Touching on paint removers. the speaker said that methylene chloride was probably the most efficient, and that care should be exercised when using some of the cheaper forms of paint remover, because of their indents ambit ity.
Mr. Fitzpayne revealed many interesting facts concerning the characteristic green uniforms worn by the transport personnel. The department, he said. employed a staff of tailors, and there were two technical assistants with expert knowledge of cloth structure and quality, in the clothing department. All linings, trimmings and waterproof materials were tested for conformity to specification, and a nide range of woollen and worsted cloths was examined for all departments in the corporation.
Cloth Tests Tensile strength and elongation test; were carried out in a certified Goodbrand machine, the samples being 6=,; ins. square. The speaker said that the bulk deliveries of cloth to the clothing department averaged about 50.000 yds. per annum. Referring to the Road Transport Executive, Mr. Fitzpayne said that it might follow the example of the Post Office and issue a standard uniform, and rnight even standardize the colour of vehicles, The Glasgow transport laboratory, he said, was sufficiently well equipped to meet all the more important requirements of a transport undertaking. Amongst other items. it contained Soxhlet estraction apparatus. a Ubbelohde mening-point instrument for greases. a nitromeler. a comparator with standard colour discs to facilitate the rapid determination of itilmonia, nitrites, dissolved oxygen and so on. There was, in addition. a Conradson apparatus to determine coke residue in lubricating oils. and a bomb calorimeter providing an accurate means for obtaining the heat value :aid sulphur content of fuels.