The Scientific Testing of Materials.
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The North British Rubber Co., Ltd., Establishes a Fine New Range 0
Laboratories.
In keeping with the continual extension of its factory, the North British Rubber Co., Ltd., has recently found it necessary to build and equip a new laboratory and experimental department in order to cope with the ever-increasing demand for the scientific control of its varied manufactures. It may be mentioned that this is the third laboratory that this company has found it necessary to install within the past 10 years, which fact accounts largely for the uni formity of its products. Everything which enters into the manufacture of North-British goods is carefully checked against standard samples and specifications for supply. Fabrics, chemicals and crude rubber all have to pass specified standard tests of quality before being accepted for delivery to the works. Such other commodities as lubricating oils, fuels, etc., are carefully watched, as well as all other necessary supplies which are as important to the smooth running of the factory as is the quality of the ingredients to be employed in the output.
The laboratory has been installed in a self-contained building, which is electrically lighted, and is supplied with electric power from its own installation, which installation also supplies current to the motors by which the testing machines, mills, etc., in the experimental department are driven, and also those for operating the stirrers, etc., in the physical and chemical laboratories. The necessary power is derived from a suction-gas engine and two dynamos —one of high and one of low voltage.
The work is divided into several departments:Research chemical laboratory ; routine chemical laboratory ; physical laboratory ; electrical laboratory; experimental department ; and the mechanical laboratory.
In the research chemical laboratory— a well-lighted and fully-equipped room, any class of chemical work can be undertaken, from the examination, for chemical purity, of factory supplies, to intricate research work, necessitating the most elaborate apparatus ; investigations of the most varied character are always to be found in process here. Where goods are intended for chemical uses, their utility is thoroughly tested before they are placed on the market, in order to ensure that they be the best possible production for the purpose required. When the finished article is to answer to a chemical specifi
cation—a very usual condition in rubber goods manufacture, samples of the finished goods are submitted for test in the laboratory before being sent out—a guarantee that the supplies are fully up to the spew
fication called for. All standard goods are likewise periodically tested as a check on the factory operations.
In the routine laboratory, the daily routine consists of tests of supplies to the factory, comprising crude rubber, chemicals, etc., in order to ensure absolute uniformity in the finished products. The North British Rubber Co. recognizes that it is of little value to examine for fault after goods are manufactured and fall short of requirements; the management prefer to have the materials tested first, eliminating any that do not fully fill the bill before they ever enter into the manufacturing stage. By this means the quality of North-British goods is fully maintained, and the reliability of the products are assured before ever leaving the factory.
In the physical laboratory, a visitor may see in operation the control of the specific gravity of finished goods—an essential point in " mechanical " goods manufacture. The demands on this laboratory have been largely increased during the last few years, owing to the great strides made in aeronautics The North British Rubber Co., Ltd., did pioneer work in the making of rubber balloon and aeroplane fabrics, and their great success can only be attributed to their scientific manufacture and control. Much thought and experiment were expended on the work in respect to testing as well as manufacture, and, as a result, the physical figures given in the lists can absolutely be relied upon. Every piece of balloon fabric manufactured is tested for hydrogen leakage in a most complete apparatus, designed in the laboratory; a portion of this equipment can be seen in one of the accompanying illustrations. In this apparatus, the hydrogen that escapes from a sample of the cloth during a definite period is collected and weighed, and thereafter the leakage rate calculated. and the fabric passed, if up to the standard set for these goods. It will readily be understood that such delicate work requires delicate instruments, and the ix-ell-equipped balance room "contains the balances
employed, each of which will weigh 1-10,000th part of a gramme.
Aeroplane fabrics are likewise tested for moisture absorption—a most particular factor in aeroplane building—to guard against the changes in a dry or humid atmosphere.
The most-interesting feature in the electrical laboratory is the installation of high-tension resistance apparatus for testing the dialectric strength of the various products manufactured by the company for use in connection with the electrical industry. Here can be seen in operation resistance tests on rubber gloves and vulcanite goods, of which the North British Rubber Co. makes large quantities, all of these products being guaranteed to withstand the voltage specified. The apparatus is capable of applying a test up to 20,000 volts, the current being generated, as previously stated, in the works power house, specially for the department. It might be mentioned, in connection with this work, that great care has to be exercised in carrying out these tests, for iliese high-voltage currents are not without their element of danger. This is readily understood when we remember that the average " pressure" employed in, say, house lighting, is about 200 volts, whereas, in the N.-B. electrical laboratory, the " pressure " is 20,000 volts. The operator is equipped with insulating clothes of heavy rubber, boots, and gloves, the machine itself. being specially insulated ; as a further precaution, the current cannot be switched on to the sample while the operator is handling the machine, the controlling switches being placed some distance away, and well guarded. It is recognized that too much care cannot be given to carrying out work of this nature.
The experimental department serves a double purpose : it is a model factory, so to speak, comprising, on a small scale, mixers, grinders, calentlers, hydrau1 lc presses, and heaters, sufficient to carry out any of the factory processes or operations on a small scale. ln this department trial compounds are put through and finished samples are turned out ready for examination before being passed to the factory ; also, this department is constantly employed by all sections of the factory for trial runs of the regular standard products for the purpose of investigating different methods of handling, such as milling or vulcanizing, in order, if possible, further to improve the methods and practice in the factory. In the mechanical laboratory arc testing machines for testing the tensile stress on all fabrics before t hey are delivered to the factory, from the lightest sheetings to the heaviest belting ducks. Nothing is allowed through unless samples fully come up to the company's specification, thus ensuring for the fabric side, as well as for the rubber, that everything is up to standard. In another part of the department is a specially-constructed dynamometer, which will give practically every possible test on a rubber sample, mcluding the ascertainment of tensile and compres:ion stresses, etc., perforation resistances, and cantilever tests for hard rubber. The machine is so arranged that these tests can be carried out over any desired range of temperature, the results being all automatically recorded, leaving no chance of error from faulty readings. The standard curves for the respective qualities of rubber are carefully filed, and samples are taken periodically from the factory and tested and compared with the standard curves to ensure that the manufacture is keeping up to quality. All new qualities are likewise thoroughly examined before they are adopted, and nothing is allowed to reach the factory unless it gives figures at least equal to the demands that will be put upon it. -The accompanying views give our readers some idea of the equipment in this up-to-date company's factory-the largest in the British Empire. With such scientific control over supplies and processes, little hesitation can be felt that the very best materials are used, and that the final products are the most suitable any rubber manufacturer can offer for their respective requirements. Nothing is left to chance or rule of thumb, but everything is carefully reasoned out and manufactured on well-defined lines from the raw materials to the finished article.