“The cover of this week’s Part shows a graving dock being filled with water through sluices in the caisson which forms the gate. The dock is situated at the western end of King George V Dock, in the Port of London, and the graving dock is 750 long. The Port of London Authority supplied the photograph from which the cover was made.”
The story of how engineers at last succeeded in linking East and West with a steel highway across the largest stretch of unbroken land in the world. The article is by C Hamilton Ellis and is concluded from part 15. It is the fifth article in the series on Railway Engineers at Work.
Many of the coral islands in the Pacific and Indian Oceans contain valuable deposits of phosphate. On Christmas Island, Nauru and Ocean Island engineers have built special plant which facilitates the speedy loading of ships in difficult conditions. There are more natural resources on these islands than is generally known, and engineers have evolved various types of plant to acquire and ship these natural deposits. This chapter tells how phosphates and other natural deposits are extracted and shipped from the Pacific island of Nauru, Ocean Island and Christmas Island. The greatest difficulty the engineers had to overcome was how to load the ships with the phosphates acquired from the islands. These coral islands have no natural harbours and are very exposed, having only a slight elevation above the level of the ocean. Nauru, for instance, is surrounded by a reef about 400 feet wide, which is dry at low tide and covered at high water to a depth of about six feet.
Building the Yenisei Bridge
“BRIDGING THE RIVER YENISEI was one of the biggest tasks in the building of the second subsection of the Mid-Siberian line. Professor L. D. Proskouriakov was responsible for the bridge, which has six spans, each 474 feet long, of steel girders. The bridge is at Krasnoyarsk, where the Yenisei is normally 2,800 feet wide. Lack of materials delayed the work for some time, and when masonry piers were set up in winter they had to be protected from the cold by wooden sheaths until the concrete and mortar had set.”
Road and rail communications in Denmark are interrupted by numerous straits and other waterways which have to be bridged or ferried. The Little Belt Bridge and the Storstrom Bridge are recent examples of the surmounting of difficulties in crossing arms of the sea. In this chapter C Hamilton Ellis describes the building of some of the largest bridges in Denmark. Denmark comprises a peninsula and numerous islands divided by sounds and other waterways, and bridges are vital links in the country’s communications. A strait known as the Storstrom is bridged by a structure which has a headway of more than 85 feet in the central spans. The Storstrom Bridge was only recently completed by a British firm of engineers, and is undoubtedly one of the most imposing bridges in Europe. A vital link in the main road and rail route between Copenhagen and Jutland is the bridge across the waterway known as the Little Belt. One of the interesting features of this bridge is that unconventional methods were used in all the underwater foundations for the piers. The chapter is concluded in part 17 and is the fifth article in the series Linking the World’s Highways.
A Steamer Being Loaded With Phosphate
“CALM WEATHER AND LOW TIDE at Nauru. A steamer is being loaded with phosphate in her forward and after holds by the two pivoted cantilever arms in which belt conveyors are installed. On either side are the lattice towers to which the cantilever loading arms are firmly secured in a strong wind. At high tide the foreshore is covered by water.”
The Lancashire cotton industry owes it existence mainly to the engineers who evolved the ingenious machines that carry out the complicated operations of spinning and weaving formerly done by hand. This chapter is by David Masters and in addition to describing the cotton mills of to-day, it shows how that great industry was built up on the works and inventions of Arkwright, Hargreaves, and other early engineers. The first of these engineers was born as early as 1704. His name was John Kay, and in 1733 he patented what is called the fly shuttle. This invention enabled the weavers’ output to be doubled, but the invention brought Kay no good. The weavers themselves were of the opinion that, because the fly shuttle enabled them to produce the same amount of work in half the time, there would be sufficient work only for half the number of weavers. They gathered together and wrecked Kay’s weaving shed and everything in his house. The weavers and cotton workers at first were the main opponents of the introduction of machinery, and James Hargreaves, the inventor of the spinning jenny and the carding machine, met with no better treatment. Samuel Crompton was another engineer who contributed to the advance of the cotton industry. For long he worked secretly to try to make a machine that would overcome the difficulties involved by the continual breaking of the thread in the process of spinning. After five years he produced a machine called a mule, which obviated such breakages. Finally, Richard Arkwright made his contribution to the industry, and, when Edmund Cartwright had supplied steam power to the weaving process, the Lancashire cotton industry was fully equipped for the enormous advance it made in the next hundred years.
“A TRACK GAUGE OF 5 FEET and a generous constructional or loading gauge make possible the building of exceptionally tall locomotives in Russia. A Russian engine may be built to a height of 17 feet from rail-level to chimney top. The 2-6-2 locomotive at the head of the train illustrated has a peculiarly Russian characteristic. This is a railed-in gallery extending from either side of the cab round the smokebox. The 5-feet track gauge is peculiar to Russia and to some bordering countries formerly Russian. Through running from other countries is therefore impossible, but within the Soviet Union enormously long through train journeys are possible.”
“CONSTRUCTION TRAIN, drawn by two wood-burning locomotives, with a trainload of materials for the laying of the Trans-Siberian Railway. The train is crossing over one of the early types of bridge used for spanning smaller waterways. In the Mid-Siberian section of line alone 574 bridges had to be built.”
“AUTOMATIC LOOMS are among the most amazing machines in industry. They stop if a thread breaks, and the shuttle is automatically recharged with a full cop, or reel, from the wheel-shaped magazine seen to the right of each loom. The shuttle, too is automatically threaded.
The Storstrom Bridge
“DECK CANTILEVER SPANS of the Storstrom Bridge consist, alternatively, of anchor arms fixed to the tops of the piers and suspended spans between them. The suspended spans are supported on cantilever arms 29 ft 2 in long, projecting from the anchor spans. The anchor spans are 189 ft 7 in long and the suspended spans 145 ft 10 in long.”
“THE THREE CENTRAL SPANS of the Storstrom Bridge allow sufficient headway for the passage of shipping. To build these spans wooden trestles were erected between the piers. A 500-tons floating crane lifted the floor girders into position, resting them alternately on the trestles and on the piers. When the floor girders were in position the arch girders and hangers were built in to support them.”
Manufacture of a Rotor Shaft
WITH one exception our previous examples of engineering practice have been concerned with what engineers produce, but the phrase "engineering practice" covers also the way in which they carry out their work. The photograph reproduced below, which was taken in the Heaton Works of C. A. Parsons and Co, Limited, shows a stage in the construction of a turbine
rotor shaft, that is, of the heavy shaft on which are mounted the blade-carrying disks.
These shafts, which have to spin round at high speeds, are subject to heavy stresses when working, and at every stage of their manufacture have to be minutely examined and subjected to numerous tests. The forging is first carefully heat-treated to remove any internal stresses set up in the steel during its passage through the press. Next, pieces are cut from it; some to be pulled apart and others bent almost double to determine lf the metal is of the required strength.
Then, when the forging has been turned in the lathe, the surface is gone over with prepared paper and what are called "sulphur-prints" are taken from it. These show up any defects in the structure of the metal and, if any non-metallic inclusions are found, they are carefully removed and the place is afterwards scrutinized through a lens. The outside of the shaft having been found satisfactory, the condition of the metal of the interior has to be investigated.
A hole is bored right through the centre of the shaft by a trepanning tool which removes a cylindrical core. This core also is sulphur-printed and examined. Test pieces are taken from it, not because it is to be used, but to find out if the forging is reasonably uniform all the way through. The task of examining the inside surface of the hole is next carried out with an instrument called a "Borescope", made by Sir Howard Grubb, Parsons and Company.
A tube about 32 in long and fitted with little rollers, so that it can be easily moved, is inserted in the hole in the shaft. One end of the tube is fitted with a powerful electric lamp, a total-reflection prism and a lens. An inspector examines the magnified image through a telescope, pulling the inner tube by stages along the hole till the whole length, in a strip about ¾ in wide has been scrutinized. The shaft is then turned round on its supports and another strip is examined, the operation being repeated until the whole surface of the hole has been gone
The forging is next subjected to magnetic and electrical tests. In the magnetic test the shaft is turned into a huge magnet by passing a current through coils suitably wound through it. The external surface is then sprayed with kerosene carrying finely-divided iron. If there are any
cracks, even if so fine as to be invisible, the powdered iron gathers thickly on the edges of the cracks and defines them. In the electric test a current is passed through the shaft and the difference of potential along its length is measured. If there is only a small drop in potential the forging may be considered sound. A final test, carried out when the disks are in place, consists of spinning the shaft round by motor at a speed of 20 to 25 per cent above its normal running speed. This test is performed in a strong chamber resembling a bomb-proof shelter, without anyone being present. Measurements and examination are made afterwards.
“FROM STORAGE BIN TO SHIP the phosphate is handled at Nauru entirely by a system of belt conveyors, as shown in the illustration above and in the diagrams below. Phosphate can be loaded at the rate of 1,000 tons an hour. The ship ties up at buoys in deep water and is ready, with steam up, to move away from the dangerous coral reef at a moment's notice if a storm should arise.”
Roving Frames in a
“ROVING FRAMES effect the last stage in the combining and drawing out of the weak strands of cotton before they go on to be spun into a strong yarn either on the mule or on the ring-frame spinning machine. The hairpin-shaped parts on the spindles in front revolve at a high speed and twist the strands as they wind them on to bobbins.”
From Storage Bin to Ship
“THE LOADING PLANT AT NAURU is shown in elevation in the diagram above and in plan in the diagram below. To the left is the conveyor belt which feeds the storage bin from the drying plant. Phosphates from the bin are carried by a gantry conveyor and emptied into a compensating hopper, a circular structure built at the end of the reinforced concrete jetty. Two gantry conveyors fed from the hopper feed the conveyor belts in the swinging cantilever arms which project out over deep water. Extending booms and telescopic delivery spouts ensure that loading can be carried on, however deep in the water the ship may be. The cantilever arms will swing so that any of the ship’s holds can be filled. In a gale the arms can be swung right round and moored to the lattice towers.”
The Little Belt Bridge
“FROM THE MASONRY PIERS of the Little Belt Bridge the spans were cantilevered out, each section being built out until it met its neighbour. The Little Belt Bridge spans a sound known as the Little Belt, between the island of Fünen and the peninsula of Jutland, Denmark. The main piers of the bridge are 47 ft 1 in wide and are built on specially designed caissons. The bridge contains about 50,000 tons of steel and 3,955,258 cubic feet of concrete.”