MECHANICAL HANDLING OF MATERIALS

Hokitika Guardian, 9 June 1931, Page 2

MECHANICAL HANDLING OF MATERIALS

RECENT TENDENCIES AND DEVELOPMENTS.

The essential mechanical elements ol modern labour-aiding machinery are of groat antiquity, but. thca - widespread application in engineering unit general industry has been almost entirely a development of the last haheentury. The adaptability of electie power and the development of the internal combustion engine have given a great impetus to the use of all mechanical bundling appliances, to which these forms of power can he so readily harnessed. The infinite variety of such appliances will continue‘to multiply as required to keep pace with the everchanging demands oi modern industry. The rationalisation of industry means business on a large scale, tile continuous flow and handling of materials in bulk, and at every stage this affords increased scope for the economic employment oi mechanical appliances. A small business.cannot find the necessary capital dor such appliances, and its limited use of them would make them unrGmunerative, The large business contrives to use such appliances < much more continuously, and the capital charges aro therefore distributed over a larger output. In other words, it is all a question of load factor. A modern flour mill working night and day six days a week nil the year rounc)..must be mechanised., to the, fullest extent, so ‘tha.t front jtbe! l)uik ' discharge‘ of grain 'by' pneiimatic-elftTOtors'from oc’eaii—ship alongside to the distribution of flour to consumers by road, rail and water there shall he a continuous process with the minimum of man-power. From a -power-producing point ofi view, manual labour in this country at 18d an hour is from 100 to 200 times a s expensive as mechanical power, assuming that electricity is available at a cost of Id a unit. The average working effort of a labourer docs not exceed one-tenth of a horse-power. At first sight it would appear from this comparison that thetre is almost unlimited scope for mechanisation and that mail should cease to : ho a hewer of ’wood and a drawer of water, that he should employ his brain-power to d ; - Tert machines rather than exercise his muscular power hr competition with cheap mechanical power. - 'While this is quite true, arid probably- on the whole’desirable, -there are- many fac-tors-to be taken'into consideration. In most mechanical appliances the)capital charges 1 ore inili-h’ ‘ -‘glb'rfter than the cost of power consumed, and in addition there! are maintenance charges, stores, etc., and these charges accrue whether the load factor of the appliance be high or low. 1 have quoted 'tY 'modern flour null as" an exaihlpe of tl high load factor; now consider a largo boating crane for use in a port as at; example of a high load factor. Such a crane may cost £BO,OOO. Capital charges, including depreciation ut 15 per cent, amount to £12,000 per annum, or, say £4O per working day. Operating expenses, including civw, luei, etc., and maintenance costs will add .another £4O per working day tnfoughiout , the year, and, as the number of heavy lifts required is very small, it is obvious that the charges .or the use of such a crane canimt be remunerative.'

There- are some general handling appliances which can be used with a certain amount of flexibility, such as quay cranes, hand and power driven trucks, tractors, barges, etc. These are suitable for all classes of goods and general cargo, and are therefore a sound investment if reasonably continuous use can be assured. 1 have found j that for general dock purposes such appliances can rarely be kept at work I for more than 1,200 hours per annum, and I,o*oo hours per annum is a good performance-. TAiis figure would bmuch reduced if warehouse, and other fixed cranes were included. British poits are much better equipped with appliances of this... class. than most of LuCir. Continental and American com petitors. Indeed, judged from a narrow conception. of direct economic justification many of them would find difficulty in rebutting, a charge of overmechanisation, at least in some of tiieir equipment. The broader view that efficient equipment induces trade, and it is tonnage that brings revenue, must however, be kept in mind. Apart from tnese general appliances special plants .or dealing wiun particular commodities and trades are being constantly devised and brought into more extended use. In the coal trade such plants are found at the colliery, on the railway, and in docks and liarhours. Coal is cleaned, graded, and delivered with the minimum of handling. . Locomotives and tenders are coated automatically,, modern electric power stations fitted with elevators and conveyors lor handling and storing coal and ashes from the moment of reception to the final dumping of the ashes. Pulverised fuel is crushed and dried by machinery and fed to the furnace by pneumatic pressure. Coaling plants for bunkering ships and for freight are available at every modern port for doing the work with speed and efficiency. Similar remarks may be applied to plant for dealing with ore, coke, sand ballast, broken stone, and chemicals. In the grain trade, the exporting ports are equipped with storage silos, elevators, and conveyors for loading ships with the utmost dispatch. Importing countries provide' similar appliances for discharge a»ud tile floating pneumatic elevator is everywhere finding increasing favour. In the imported meat trade, both chi!l-

ed beef and frozen mutton are manhandled as little as possible, and elevators, conveyors, overhead runaways, lifts, lowerers, electric trucks, and automatic scales are being pressed into

service. In the .fruit trade, machinery is in-, creasingly employed for sorting, grading,- packing and delivery. Imported cheese is largely handled hv machinery, arid hogsheads of tobacco are stacked for maturing in bonded warehouses by means of quick, light overhead cranes. In the transport trades generally, these special plants can he applied successfully to hulk cargoes where there is a regular flow of the commodity irom the producer to the consumer.' Storage tor long periods, which interrupts the How, is a disadvantage and often prevents the economic use o. machinery. ’the timber trade is a good illustration of tins point. Soft timber from the Baltic, which is imported in large quantities during the summer months, is stored either under cover or in the open for seasoning, and is distributed in sinal. quantities to meet the day-to-day requirements of consumers. On the average, a timber shed is filled and emptied perhaps once or twice a year, and there.ore the load factor is too low to justify, the use of expensive machinery, which would be idle most of the time.

Road transport by commercial mct-or-vohicles has recently shown remarkable progress, especially for long distances and heavy loads. This heavy and fast traffic demands substantial roads and bridges. Congestion and delays are expensive and therefore road and bridge improvements aie im perative. (Jivu aviation is m its mlan cy, but already for passengers and mail uamc it is p.ayuig an important part in speeding up cdimmumcauons, and no doutn liner classes or goods will be increasingly -truuspoited by air route m thu-.iikuiv. An, inu-ivsung develop-

ment in dry-clocking slops is the piuvis.on of a powLii'-urivcn leauuig-in girder spanning the dry dock winch engages the stem of the snip aim I keeps it plumb over the middle of the ! ktei blocks. 'Jlie bilge keels are at o operated by media meal means, thus saving imn.ii time in the rigging of timber shores from the dry dock altars. Apart from transport, many traues are ueing quietly revolutionised by trie use or automatic appliances. Large, bakeries turning out thousands of foav,-, es an hour o. nian'y different sizes 1 anil shapes are scientifically controlled ‘auu, equipped wild machinery to reduce,, manual handlingLalmost to the vaiiisiiilig point, as also are biscuit factor-, les. .in breweries and Iwine vaults; flic botties are washed, conveyed, labelled. 1 and’ 'dtfiiWfdl "by mnchimjry. Cement,factories, j.nunnjng . night and, .day; * employ punfpi, eb[nveydris, elevau, ors, rotary kilns, sacking appliances, etc., to make tiie whom process as ine;, ehauic-ul as possible, fine beet-sugar industry is also developing its-own special machinery for handling, separating, and washing purposes. In all forms onew works construction and building labour-niding appliances arc used to an ever increasing extent, Progress plans are prepared, plant and materials arrive when required, the time for completion being shortened and ultimate cost reduced. Excavating machinery' in the form of grabs, navvies, anil" land dredgers largely replace hand labour. Concrete mixers and shoots operate in the same' direction. Hoists and cranes place materials where ; required on any part oi the site. In woikshops and ioundries cranes and runaways' are commonplace. Moreover, precision tools machine materials to exact sizes within limit 'gauges and'the fitter is not required to show his skill with the file, scraper, hammer and chisel to the same extent as his father. The fitter’s work is now largely that of assembling, especially in mass-pro-duction workshops, but even in repair work the use of electric, pneumatic and hydraulic tools of a portable character largely reduces hand labour. Containers of all types are being increasingly used in all directions, from the smallest packets, tins, cartons, and bottles to the largest oil tanks for rail and road transport. Large containers for cross-Channel traffic are also showing rapid advancement. In a recent development in the milk trade waxed , paper containers in pint and quart sizes are being used as an alternative to bottles or cans. These containers are filled and sealed with great rapid- j itv, and on hygienic grounds are considered an improvement. The container system in all its forms is a great aid to the employment of automatic handling machinery, as uniformity of size and weight s'mp’ifies the preb’em.

Standardixation is another factor which contributes its quota in facilitating the adoption of handling appliances. Human nature craves for variety, but this craving needs to be controlled, and the specifications of the British Engineering Standards Committee are doing splendid work in this direction.

Many handling appliances have not been 1 mentioned, and in this brief survey it is only possible to enumerate some of the more important. Aerial ropeways, which play such an important part in conveying materials to sites difficult of access, overhead magnet cranes, petrol-electric runabout cranes, transporters, escalators, petrol locomotives, road trolleys for heavy loads, pilers. stackers, shakers, etc. must not be overlooked.

Tn all well-established forms of mechanical ham’limr r;y , ' : "’.''er, British products are unsurpassed for quality. They are robust in design and well fitted for their purpose. Bricks are in many eases higher than these of some competing foreign makes, and. however adequate the explanation of this fact, it is none the less to lie deplored, and should he remedied as soon as possible. Some foreign countries apear to show a greater readiness to

apply machinery in new directions, but it appears clear that the initiative in all sound development must arise from the demands of progressive industry itself rather than from the engineering manufacturer. For economic reasons it is inevitable that rationalisation of industry must proceed and at every stacre and progressively this process will make pew demands on the skill of British engineers in devising appropriate machinery.