Document 44VX08X6MXyrBbNmMpJ629q0V

20 V. I I Manufacturing ond Management, July IQ. 1956 Dust Hazard in Industry Details Given of Department of Health Survey of Dusty Trades . . . Problems of Dust Control ... Examples of Dust Collection Equipment Available : j An Editoriol Stoff Article NHALATION of large quantities of dust has long Victorian Survey ' I' lhdaiast.tilrsofbii-neeencshmee,aonninlfthiranuaedtgrvicuyoeo.sndgtunbocsieEstofseeflh,flndeoascrrautstmsoscturhfasduhialiadeasvdadneu,ndasgrpbetoeeaptrehfraottneiorucrtiunchmmdlleaeaearsditllnyhtebho.y.mdotsvoat.EhenerfypSferietnecihnvtsvesdeteuarnoalslax-tlst"tuthrhanyaAgdatieeedsrnsuteuhisnretdvieivsVsyiuiscapiotreoesnrrecviareiosio.nfiouttlnshyeo"hifeVSaDicilirttdh.oaDrchia.taSnLzd.aH'TCrdeJ.yaTinlhthtohsmDeeaveespi1r,naadsrlhtumd'osuwetrsneitatdy,l countries, including England, U.SA and Australia An extensive x-ray survey of 4,000 Melbourne have introduced regulations aimed at dust suppres workers disclosed 856 cases of silicosis and asbestosis, sion, especially in mines and foundries. which are serious lung diseases. Many workers are being slowly incapacitated by dust without realising Types of Dusts . it Others, complaining of shortness of breath, tired ness, or a cough, had not suspected the cause. -Types of dusts encountered in industry include toxic and non-toxic dusts, explosive dusts, son-harmful nuisance dusts, and dust arising from the powdered form of products and by-products being manufactured. - Workers exposed to harmful dust include miners, moulders, potters, brick and tile makers, furnace bricklayers, mineral earth operatives, masons and quanymen, boiler makers, welders and metal polishers. I 1 Toxic dusts are produced from poisonous material, for example lead, but there are several non-toxic . dusts in a finely divided state, which are also injurious - to health although the material from which the dust is derived is sot in itself harmful. Examples are silica and asbestos. * -. < Dusts that are explosive when present in air in certain 'proportions include carbonaceous materials such as coal and grain and also many metallic dusts such as those from aluminium and titanium. Incidence of Dust Victims The number of known dust victims in Victoria, f before the Health Department survey, was 522, I including 343 miners. The investigation brought the | number up to L100, inclusive of 565 miners. *j Silicosis has long been recognised as an occupa- 4 tional disease in mining, but its extent in Australian 2 industry was not realised prior to the survey. d . This article discusses problems arising from the presence of harmful- dusts associated with many industries. Jt is generally assumed that the main -danger to health comes from dust particles which Asbestosis was diagnosed in a third of the asbestos '] workers tested. Of 260 x-rayed, the health of 50 was j definitely impaired and 40 others showed early effects of the disease. * ;* J are less than five, microns in dia. (a micron (p)=ooe- More than 20 workers have become ill in die past thousandth part of a millimetre). __ few months after inhaling vanadium dust, mainlv /This means that dangerous dust is invisible to the through cleaning oil "burning furnaces, although naked eye. It can be detected and estimated by protected by masks and protective clothing. suitable instruments, involving the use of micro scopical methods of size ranging and counting. A . Harmful Dusts and their Effects -- ' '. method of studying the behavior of resoirable dust has been evolved by the Inspector of Factories in Silica .~ ." ; . England, employing intense illumination and . Prolonged breathing of dust containing silica icinematography. \ , particles causes silicosis. . l i f t I Vrcnufcctwnog end AAc,'o;*"'e-r. July 10. 195c 2: '*'-V ' ' .'' '" '* *. 1 Fig. 1 TkU' ess* Is e typical USeafic altar 24 yan Is a alaarel arisdls? votkfc. - Fig. 2 (ri^ht)--A prevad oskaatctlc--<ssfinsad by lha praaasca si eabastecic bodiaa la tba sputum. . ` The abundance of silica in the earth's crust and the large number of people engaged in occupations involving the inhalation cf dust containing free silica, make silicosis the most important of diseases classified under the general Reading of pneumoconiosis. Silica particles, once in the lung, set up a chemical action. Nodules of connective tissue are formed which eventually greatly interfere with the elasticity of the lungs. Tuberculosis and silicosis are closely associated, especially in quartz miners. X*ray is the principle means of diaenosing silicosis, although the radiological picture dees not necessarily give a definite finding in all cases. Shortness of breath is one of the most common sym***oms of silicosis. The disease takes from about five twenty years to gain a grip, according to intensity of exposure. Apart from removal from the hazard, change to an open-air life, and physiotherapy to improve lung capacity, there is no known treatment for silicosis. i *.: that the condition' is set up by the mechanical intrusion of asbestos fibres into * the substance of the lungs. People prone to the disease are those handling asbestos in its raw state or processing it to make lagging materials; also operatives sawing and cutting any finished product containing asbestos such as brake. linings; asbestos sheeting and various insulating materials. Dismantling old dry lagging is a hazar dous occupation. Once established, asbestosis constitutes a grave threat to life and health. Symptoms are shortness of breathy tightness and pain in the chest, together with loss ofj energy and tiredness. Some patients show marked improvement after a course of physiotherapy. Stringent regulations aimed at controlling the hazard'of asbestos dust have been framed in Victoria, and when these come into force, it is hoped that the incidence of asbestosis will steadily drop. Vanadium . _ .* * Surveys made by the- Division of Industrial Hygiene, Victorian Department of Health, prove that silicosis is a prevalent and serious disease in Victoria; resulting in incapacity or diminishing efficiency. Steps have been taken to eliminate siliceous dust, but much remains to be Gone in "effectively controlling* industrial hazardsjassodaTSc-with the dusty trades. Vanadium is a new*dusrbazard. Vanadium remains in residual'heavy oilT after more volatile fractions, such as petrol; paraffin and diesel oil have been distilled. It is a constituent of the exhausts of gas turbines using heavy residual oils. Operatives clean ing oil-fired boilers or relining combustion chambers are exposed to .vanadium dust. ' A chest x-ray of a typical sufferer from silicosis- is shown m Fig. 1, and from asoestosis in Fig. 2. Asbestos - Asbestosis is a disease caused by the inhalation of asbestos dust (magnesium silicate). It is believed Symptoms - of vanadium dust' poisoning include- imtation of the mucous membrane, digestive disturb ance, nervous troubles and even blindness. . Precautions against vanadium poisoning comprise efficient ventilation and hygiene, and use of respira tory apparatus, special overalls and goggles. Vr? I' -. ~............ 22 Mcmjfoct<jfi<'>G and Management, July 10. 1956 * *( r k- V :' W<* a'_*' -* Other Dusts Talc, used in rubber factories, cotton dust, sugar cane dust, . and .coal dust can cause fibrositis in the lungs'. . . --. Iron dust can produce a radiological effect similar to silicosis but with little or no symptoms. - Most lead poisoning is caused by the inhalation of lead dust They are-- Hood to suck in dust laden air; . Hose to suck away dust laden air; Filter to clean dust laden air; . Pan to induce air movement; `Motor to drive the fan. . Protective Equipment * Industrial equipment available for protection against dust includes gas masks and respirators of various kinds. Filter respirators are used for protec tion against silica dust and toxic dusts. Distant breathing hoods are commonly used by sand blasters. ' However, it is generally conceded that collection of dust at source and so preventing its dissemination is the best method of combating the dust problem. In machine shops, dust collection may be made either by general room ventilation or by hoods adjacent to the work bench or by collection at source. A comparison of the rate of fall of spherical particles of different sizes shows the inefficiency of the first two methods. _ A particle of 0.5 micron size has a termina] velocity of .001 cm. per sec. in still air while a particle of 10 micron size increases die rate to 0.3 cm.* per sec, and the rate of a 20 micron particle rises to IS cm. per sec- ' __ . * Therefore, small harmful particles dispersed in -normal air currents encountered in factories or foundries, may well remain in suspension for very long periods, with harmful results to operators. If these particles are collected at source, such a condition cannot occur. .- Dust Extraction Fundamentals Dust extraction equipment can be resolved into the series connected components shown in Fig. 3. Flf. 4 --' Suzisc* tfp* Doatuctor LYHY cowL with - Alternatively, the vacuum source to induce air movement may be an air-driven eductor, as used in t the Dustuctor system, described later. } Factors influencing the choice of dust extraction dements include-- *` Hood. .Location as near to zone of dust generation as working space permits. Shaped to "eaten heavier particles at some point on natural trajectories. To capture finely dispersed particles, air entering the hood must sweep past the dust 2one at a speed sufficient to deflect them in and lower the concentra tion of contaminant to a pathologically safe level. ifocturing end Mcnc^e^e-t, Jwty !Q, 1956 23 *. Length chosen to comoly with space ements. Inside diameter such that flow proan air velocity more than sufficient to transust collected a*t the hood, to the filter. Hose withstand dust abrasion of inside surface, which i be smooth to minimise friction losses. er. There are five main types of filters; 1. a (gravity, baffles, cyclones); 2. Mechanical ns, bags, etc.); 3. Viscous; A. Washers; S. rostatic. . , oice of filter is influenced by the nature and nt of generated dust. The system employs a low volume high velocity air stream. Instead of using a large flow of air' vaguely, suction is concentrated at selected points, resulting in a substantial economy of air. . After entraining dust in the air stream, it is neces sary to filter and separate it from the air stream by means of suitable collectors. Dust collection units are mainly small portable or semi-portable units comprising a high efficiency cyclone or cyclones followed by a high grade doth filter. The cyclones are responsible for collecting and depositing into a container over 95 p.c. of the dust and form a primary separation unit ensuring minimum dust passing to the cloth filter. This filter is of a specially chosen material giving little back pressure, while cleaning *nd replacement are easily effected. The vacuum source may be either a built-in airdriven eductor or separately electrically driven fan or vacuum pump. Fie. 8 'Cowl el & fruftetor L.V. H.V. twfae* erisd*7. Efficiency These collectors are all capable of filtering the dust laden air to a high degree of efficiency. .. The standard demanded by Mining Health Authori-. ties in England requires that sot more, than .300; particles per c.c. of air, of size range 0.5 to 5 micron'-; be dispersed to the atmosphere after filtration. The filter units used in the Dustuctor system meet this requirement. Dustuctor System * Dust collection methods include the Dustuctor tem, made in England, and distributed in Australia Holman Bros. (Aust.) Tty. Ltd. In the Dustuctor system, dust from power tools entrained in a high velocity air stream virtually at e point of generation, by means of specially signed cowls, sleeves or extraction rings. Fie* ---Oo*wot Wwiae Wiw flo* ult dlMl to 4ui ooQ*c- Applications Successful applications of the Dustuctor system to portable power tools include surface grinders as used on castings, radial grinders, portable abrasive wheels, and swing frame grinders (see Figs. 4 and 5). Fettiing Chisel Sleeve The Dustuctor fettling chisel sleeve, which is made of rubber, offers a simple and effective means of collecting fine and dangerous dust created at tire edge of a fettling chisel, used in foundries for cleaning and de-scaling castings, or similar operations. The dust is drawn up through two ducts in the sleeve, either- side of the cutting edge of the chisel and led away through a light | in. plastic~hose for safe disposal These ''ducts -should be kegt about 1 in. from the cutting edge and thTubber may be-cut back-as-the chisel shortens during'its working life. _ ~ -- , The sleeve fr`firmly "positioned by an annular ring ground in the octagonal chisel which coincides with a -ring in the sleeve itself. The sleeve is convenient to use andjts-shock absorbing qualities are"a comfort to the operator.** . ,,. *'. . A vacuum "of 5 is. of mercury is' required at which depression the sleeve passes a volume of &S cuiF of air per minute. The sleeve, which is illustrated in Fig. 6, is designed for use with dust collection units described above. --  tj - .* H * JJ :i 24 Monufocturing od Monogement, July 10. 1956 Hollow Chisels '?' - . * .. downward in the rear compartment. The air is then drawn upward, this chance of direction removing all In another method of dust'control for 'fettling but the finest particles of dust. chisels, used experimentally in England, local exhaust ventilation is applied through,a hollow chisel, and the dust extracted through the pneumatic hammer. Exhaust air can be provided by an eductor or rotary exhauster. , The fine dust is arrested on the.outside of 21 filter bags, suspended from a frame in the front compart ment, and providing a total filter surface of approx. 265 sq. ft. The filter bags may be agitated by means of a lever on the side of the unit, thus allowing dust . This method is similar to a successful dust-control to fall into a tray for removal. system in mines, in which dust is extracted through The "Power" dust extractor system has been applied '* hollow drill and taken away through the pneumatic successfully in the manufacturer's own machine shop hammer itself. not only to surface grinders, but to lathes and milling A hollow chisel has been used for fettling rough machines when used for^msRSJJfning cast iron. Hoods, castings and cinematograph films show that the dust specially designed to suit the individual machines, was brought under control. are used for dust collection at source. "Power* Dust Extractor The "Power" dust extractor, an internal view of which is shown in Fig. 7, is manufactured by Pauer fic Co. Pty. Ltd., North Melbourne, Victoria, and was designed for use with stationary surface grinders and similar applications. Under the action of a centrifugal exhaust fan, powered by a i h.p. 2,900 r.p.m. totally enclosed motor, dust is drawn from the point of generation by means of a specialty designed hood. Dust-laden air .is conveyed throuen special rubber suction hose, 2 in. inside dia., to Hie top of the unit and drawn Fig. 7--lnUraal ri*w st Power dust extractor thowisq robber raettes bsM. ezbaset Sob. and filter begs. Doily News Sheet Under the bright colored banner of "Today's AJ?.M. News" Melbourne mill manager, Mr. Hugh Rogers, is producing a daily news page which is proving extremely popular at the mul..., . . The page contains up to six short paragraphs about mill and company activities. ; ` . - \ The headed sheet on which it is fordigraphed is in a different bright color for each day of the week, so that it will not be confused with other notices and to make it easy to see. . ' Ten Ways of Saving Office Space * 1. Microfilm storage records. 2. Use five-drawer filing cabinets. 3. Use functional equipment. 4. Standardise size of offices. 5. Provide standard aisle space. 6. Arrange office to suit the work flow. 7. Use movabJe'partitions. 8. Beduce the number of partitions between departments. - 9. Provide centralised reception space. * 10. Provide a centralised cpmpany library. ! THE GOAL "The primary qoal of any industry must be to make a better and better product for more and more people at a lower and lower cost, and still retain a tor profit"--Mr. Walter W. KiUough, president Melbourne Division,. Australian Institute of Manage ment __ . *