Document zo7mxyv1J0408jqXjxYwD92j7

FILE NAME: Trade Publications (TR) DATE: 1941 Feb DOC#: TR045 DOCUMENT DESCRIPTION: Trade Journal Article - Aim Dust Abatement Efforts at Finest Particle Sizes Established 1904 with w hich has b een co m b in ed C em en t Age-, New York, and Concrete E ngineering, C leveland CEMENT MILL EDITION Published m on th ly by CONCRETE PUBLISHING CORP. 4 0 0 W est M adison Street Chicago* Illinois T elep hone CENtral 8 0 2 2 'J o t - FEBRUARY 1941 Volume 49 i\0, 2 CEMENT MILL SECTION LN THE IINTERESTS OF Those engaged in the manufacture of Portland cement and related products. Its pages are devoted to discussion of plant design, management, operation, production, efficiency, chemical research and control, quarry operation, progress and news of the industry. The Cement Mdl Edition also contains all the material published in the Regular Edition, thus providing mill operating offi cials with progressive data on the uses and merchandising of their products and estab lishing for them valuable points of contact with the user of the materials thev produce. Subscription price is $3 00 a year in the United States and its possessions and Mexico. One Dollar additional for postage in all other countries. Current copies, 10 cents each. NORM AN M. STINEM AN E d ito r J. C. W ITT C o n su ltin g Editor Louis B rook m an. Jr., P u blisher L. M oeller, C irculation M anager D . T . Papineau* P ro m o tio n M anager _____ n "Thu Mue Slurry-D rying Heat R ecuperator Saves Fuel and Increases O u tp u t ......-.............................................................................. . . 118 P e n u a n e n te P la n t to P r o d u c e B y -P r o d u c ts ............. 119 E ffect o f T em peratureo n H igh-A lum inaC em ent 120 Free T esting Service for W ar M inerals O ffered bv C alaveras .................................................................................. 120 R eporting and K eeping R ecords o f A bsence D ue to S ic k n e s s ............ 121 W hat H appens D u rin g B u r n in g o f C lin k er? . - .. 122 A im D u st A batem ent E fforts at F in est P articles Sizes .. 123 P ow erful Electric M otor D rives B ig K iln at Perm anente P la n t .................................................................................. 124 C alifornia Portland C elebrates F iftie th A nniversary at C o lto n P la n t ................................................ V ibrations from Quarry B lasts C ause N o D am age to B u i l d i n g s .............................................................. W e ld in g Is K ey to E ffic ie n t P la n t M a in te n a n c e ...................1 2 6 E d ito r ia l D is c u s s io n ................................................................................. 1 2 7 A. 8l*s Ta*lc to r 1941 Statin* th Export Problem How the Industry Vlll Expand Individuals A ffected in D ifferent W ays by S ilica Dust ...128 Production and Shipm ents in 1940 Pass Mark o f 130 M illio n B arrels ......................................................... R e g io n a l S a fe ty C o n fe r e n c e s S c h e d u le d f o r 1 9 4 1 ............. 1 2 9 N a tio n 's Q u a rries P r o v id e M ore E m p l o y m e n t ....................... 1 3 0 M isso u r i P o r tla n d 's F iftie th A n n iv e r s a r y ....................................1 3 0 M ill E q u ip m e n t .........................................................................................1 31 M en a n d M ills........................................................................................ 1 3 2 R epresentatives N ew Y'ork C ity E . M acdonald Bacon 17 W est 4 5 th -- R oom 909 Longacre 3-5260 San Francisco: D on Harway la a M ontgom ery Street Exbrook 6029 Advertisers' Index* P age 9 8 CHARTER MEMBER Associated Business Papers Audit Bureau o f Circulations Indexed In INDUSTRIAL ARTS INDEX Los A ngeles: D on Harway & Co. 3 1 8 W est N inth Street Tucker 9706 Copyright, 1941, by C oncrete P u b lish in g Corp. C O N C R E T E -- Cement Mill Section -- February. 1941 Page 117 124 125 129 Ham o g$r m I? ^ Show ing m echanical details oi recuperator Idruni, u h rre the slutiv prtximitated Iby paddle-> mounted on the r-hatt ot the ^fscrew to tn e v o i This soreu <.unu*\oi >hatt t o t a l s at a f-speed exceeding - d o i.p.m.. with the re- i|<suit that the d u r r \ i' atomized and Lispraved th rough tile hot kiln 'ia^Cb pd-^- int*-slo^lv through the diurn fh e ^ p ra \- ing action pi nje< t? tlie d u n * against the 'hot shell ot the d iu m wlien* the d m o i' p? dried veiv q u u h 1' l`<au?<* <t the heahU heated condition ot tlie 'h ell. The p a d dles mounted hi tin* -halt ot the m reu conveyor for the nu }*<- <p{ pr<'je<.tui`_r the slurrv. now tin- additional p u r pose of knor k !TIC the d n e d d i m \ "tf the .shell. Moisture Not Ail Rem oved On the averait- m-lailali<>n. (lie tom perature of die kdn LM-e- p a ^ in ii lluoutrii If.the drum am! i''m m lir: n n o -tu ie tj.>m the spraved -1111 : \ a ill have 'h o p p e d to about 250 dec 1' 'u tin- iiinr these ea-epass thromrli Ibe - n uixi -et ..I ,,it In.)e~ at the t a r end ot til.- liruin Not all 111o i-1me i- t a 11111 W( 1 lim n tlt*` slurrv --or the tiltei . akr i- it mieht more prop-i K |,e tei med at tin-' -eim-<lr\ stage. \ssum ine a - i-c utmte the tan slurrv ha- a m m -tuie "iiteut -iitiii'w hei (` around >6 ;,i Id pet . i in. the inm -tiue oi the t e m i . l u ake" a 111 l'e .1111mid 111 to 19 per <cttl Tht- "'.ike now leaves the drum, h a w ne the teel ot a titled produot. hut a* (nal 1\ atinan v null cateti, contaminar atminii III to I 9 por cent of nut i-tu i sK.-t Inasmui li a- tlu- lu\tt m u p n a t m stalation i- above tin- dio hai ce end the kiln, tintrap, pm t, d Tin- cotuft ur -,-mI <11 \ dm i-h, nudit mu-t md ot the kiln iniMii' i>f a Millie it ("arti, all. dll [In in--,! r* to ill i\e I ' t II < Mit t.f tlm slurry, there are several reasons why this is not done. Experience has shown that no slurry-drying or slurry-filtering operations should go too far in the mat ter of driving out the moisture. As a matter of fact, 15 per cent is about the lowest allowable limit, if drying is c a r ried to a point where the moisture con tent is less than the limit just named, the dried product acts like cement rock or other kinds of raw materials. Good Performance In contrast, when the semi-drv prod uct still contains from 15 to 19 per cent ol moisture it enters the kiln in a some what puffed condition, due to the action ot the carbon dioxide in the effluent rases. Under this condition the heat in the kiln penetrates the product readilv. and COgas escapes without dilhcultv. and the burning activ ities are aided. A tvpical installation of the heat re cuperator here illustrated is that hooked up with a kiln 210 ft. long and having diameters of 10 ft. and 11 ft. 3 in., located in a Western cement plant. Before the recuperator was installed the kiln turned out a daily production of around 1,650 bbl. of clinker, operating with slurry con taining 11 per cent of moisture. The -auie kiln, after being equipped with this lecuperator and having the moisture content of the product reduced to 19 per cent, had an average dailv production of 1.1125 hhl. fuel consumption, prim to the instal lation. was 1l. f gallons ot oil per barrel. \fter the installation was Hit in opera tion the average was ii.6 calions per barrel. Ickiioit/ei/gmeuf: The heat rccuper.ttoi here described and illustrated is known as the Colum-Lanii recuperator, inanufactined bv T ravlor Eusineering & Manilla turinu Co.. Vllentown. Pennsyl- VH I M . Perm anent Plant to Produce By-Products T'H E new 12.<KH)-barrel-per-day plant of the Perniauente Corporation near Los Altos. Calif., has set what is probably an all-time low in raw-grinding cost, says Oliver Bowles, in a report to the li. S. Bureau of Mines. Grinding is done in two stages, the first consisting of ball mills in closed circuit with Dorr classi fiers. giving a minus to-mesh product. The second stage consists of hall mills in closed circuit with Dorr howl classi fiers. giving a product of which 96 per cent is minus 200-mesh. The power con sumption is said to be 10 to 11 kilowatthours pel barrel of cement. Most cement plants make nothing ex cept cement, or cement and lime, at the most. The Permanente Corporation is pioneering in the field of bv-products. which eventuallv mav include limestone for beet-sugar factories and concrete ag gregate. lime, stone sand, solid carbon dioxide, and potash. The stone for beetsugar use must be chert-free. The chertv limestone is similar in appearance to the pure stone, hut under a fluorescent light thechert assumes such a distinctive color ation that it can be removed bv hand on a licking belt, and in this wav the work is greatlv s 'm / l i 'i H . C O N C R E T E - Cement Mill Section-- February, 1941 Page 119 Aim Dust-Abatement Efforts at Finest Particle Sizes THE Report of the Preventive Engi neering Committee of the Air Hygiene Foundation was presented by Prof. Philip Drinker, of Harvard, Committee Chairman, at the fifth annual meeting of the Foundation, held at Pittsburgh on November 12, 1940. An abstract of the report is given here. The report deals with fumes from welding oper ations as well as with the elimination of fine particles of stone dust.--Editor. DURING the past hcal vear ot the Air Hvgiene Foundation, one fel lowship has been maintained at the Harvard School ot Public Health. The incumbent is Bernaid D. lebbens. who is a candidate for the Dot tut ate ot Sci ence Degree at H at\aid . He has woiked on two problem-, one involvin'.? a tudv of particle -ize in lelation to dli< ods. and the other eoinpi dug a tudv ul the gases and visible Untie evolved in art welding with coated iod-. Study of Particle Size For the studies on particle -i/e and silicosis, dust samples of iinelv-ground flint. 99.3 per cent SiO? were prepated in fractions of 3.3. 1.7. l.O. and O.h microns. As stated in our 19.19 tepoit. the ob ject of Mr. Tebbens work with si/.ed pat tides was to stud' the relationship of size to potency i with respect to silicosis I. It was generallv admitted that the potencv increased as the sue decreased: hut. ro far as we knew, no studies had been made (and certainly none published l which at tempted to answer this question with pathological proof, IVe aie indebted to Dr. R. Z. Schulz, of the Department of Pathology. Harvard Medical School, for his co-operation in this work. Engineers are concerned with particle size in the causation of silicosis, because we. and not the phvsicians. are responsi ble for dust control and tor making esti mates or counts of dust com durations. From the icsults of Tebbens and Schulz, it is evident that methods and apparatus designed to abate dustiness or to esti mate dust roncentrations should be d i rected especiallv against the particles well below land not above I l microti in size. Welding with Coated Rods A part of Mr. Tebbens' fellowship work has been devoted to a study of the nature and quantity of the fumes and gases liberated during arc welding with coated rods. Not all electric welding to day is done with coated rods, hut their use is increasing lapidlv. In the case of alloy steels and ot non-ferrous metal, coated rods are the rule and not the ex ception. In general, the primary pur pose of the coating is to shield both the arc and the hot metal Irani reaction with constituents of the air. Time would riot permit tudving the full list of the coatings used on modern welding rods, or the products they give oR in the arc. ith the help ol welding experts from the General Electric Companv. who supplied all the equipment needed lor this studv. we selected a num ber of representative rods, of which the makers generallv furnished the approxi mate analvses. In tlio-e few cases where aualvses weie not available, it was not difficult to deteimme the essential ingre dients and to cheek them against the products ot combustion in the arc. F.verv effort lias been made not to divulge anv trade or manufacturing secrets regard ing tile exact nature ol the coatings. .1. Lou Carbon Steel Electrodes: -- Seven different electrodes were studied in three sizes, a '32. 1 i- and a / 16 of an inch. The coatings contained the fol lowing: Ferromanganese, the Mu serv ing as a deoxidizer. Various silicates, including asbes tos. with small amounts of free silica. Sodium silicate as binder. Titanium dioxide as an arc stabil izer. Carbohvdrates to furnish a reduc ing atmosphere. 8. Steel Allots and Xon-Ferrous A l l o t s :--The coatings of these rods all contain fluorides, usually carbonates, and some silicates. The coating of rods for welding aluminum contained chlo rides. while one allov rod contained boiates. CEMENT MILsLE Fumes from Coatings In general, all rods and all coatings C gave off a visible fume or smoke in which T the qualitative composition was predict able from the analvses of the rods, in I addition, we looked for any volatile fluorine compounds, as well as carbon 0 monoxide, chlorine or hydrochloric acid, N and especially oxides of nitrogen. Welding was done in a gas chamber equipped with a special exhauster and a hood placed near the welding work. Beads were welded across small metal plates, and the gases and fumes from the arc were drawn into the hood by the exhauster. Samples of gas and of the visible fume were taken from the flue pipe and analyzed. From a considerable eries of such analyses, it was possible to construct a table. Some Rules for Welding In general, ue believe thal modern electric wriding is a safe job, providing that the worker observe* certain rules. He m:t avoid ultra-violet light from ih carc. Hi? >kiu. cspcciallv hand?, face, and neck. must be protected. NXe have no fault to itnd with the conventional ~afetv practice, with regard to the-e items. He should nut weld in confined spaces, like tank?, miles? well ventilated, or unIc?a be is -u p p h e d with an air nui?k. if the (oruentratiun id Wrdldc hunes i? kept within reasonable limit? In mean? ol ap p to p n a te ventilation, there will he no n?k ol pnMmiit<z from \ ( ) > Fhi^ dor> not mean that NOj and visible Imne? aie given wlf m anv constant ratio. Fliev are not. But low concentrations of visible fume-, such as 20 to 2.S iri"Scu.in., preclude anv pos?ibilit\ ol harm i rom breathing ga>eou? impurities. \entilatum requnements f ( Jl ot un healed lank? with lateral exhausts were found to vaiv as follows: t ulUmirtl hood: ij =. `J.'t I widdi *1 1* i It-niuh ` * i %cf.oilv 11 Flanged IhhmK: Ot = 1.9 i widlli i 1 * i Icmitli i " ' i velocityi1 The optimum height of flange is that equal to tank width, and the optimum llauge inclination is the maximum allow able without interfereme with industrial operations. Slot veloeitv or slot width aie unsatisfactoiy criteria of hood performance, file important factoi is the qiuntitv of air handled. The depth ot liquid urface below the dot does not affect greatlv the charac teristic of hood performance, hut mar have an important effect on evaporation and entrainment of liquid. C O N C R E T E -- Cement Mill Section -- February. 1941 Page 123 90 CONCRETE February, 1991 ADVERTISERS' INDEX A cqua-Pruf, Inc. . . .............................. 92 Advance C ast Stone Co......................................................... 67 Aeroil B urner Co., Inc.................................................................. 86 Allan Mfg. 8: W elding1C om pany............................................ 94 American A ggregate Co................................................................ 94 Anchor Concrete Mchy. Co........................................................ 82 Anchor Div. of Consolidated Concrete Machinery ** Corp.............................................-............................... 57-64 IncT Autom atic Spring Coiling Co.................................................... 85 Bassett F oundry C o ............................................................ 57 Besser M anufacturing Co.. . ........................... 57-64 Incl Bismarck H o t e l ............................. 86 Biystone C o rp .............................................................................. 83 Butler Bin Co................................................................................. 31 Calcium Chloride ........ .............................. 71 Celotex Corp.. T h e ................................................................... 79 C. H. & E. Mfg. Co.................................................................... 85 Classified Liners ................... 86 Colorcrete Industries. In c ............................... ...................53 Commercial Shearing & Stam ping Co................................. 37-78 Concrete Equipm ent Co.......................................... 85-95 Concrete Pipe M achinery Co...................... IX Concrete T ran sp o rt M ixer Co...................................................... 78 Consolidated Concrete M achinery C orp.................57-64 lucl. Construction M achinery C om pany........................................... 82 Connell. E. L., Co........................................................................ 86 Doustlas Fir P hm ood A ssn........................................................ 99 Dimn Mfg. Co.. W. E ...................................................................... 43 Flint 8: W alling Mfg. Co.. Inc...................................................... 84 Gclbman. Loui^ .................................... 75 H arbor Plyw ood C orporation.......................................................69 Hauck Mfg. Co.............................. . .............. 86 Haydite C orp.....................................................................................94 Heitzel Steel Form & Iro n Co. ................................................ 30 Hotel Sherm an ............................................................................ 74 Ideal Div. of Consolidated Concrete Mchy Corp. ...........................................................................................57-64 Incl. Jaeger M achine Company. T h e................................................. 19 Johnson Co., C. S...................................................................... 84 Jo ltc re te .......................................................................................... 75 Kent Machine Com pany.................................................. 37-47 Kirk 8c Blum Mfg. Co., T he............. .................................. ...... 92 K oehring Company ..................................................................... 27 K oudelka Supply & Mch. Co..................................................... 86 K ram er Corp., T he....................................................................... 29 L ackey, H . W ................................................................................ 8 6 / L ehigh Portland Cement Co..................................................... ~ 51 L iving-Stone Co............................................. - ............................. 86 Lone S tar Cement C orp................................................. - .......... 25 Mali T ool Co............................ - ..................................... ..... 87 M arquette Cement Mfg. Co.............................................................. M aster Builders Co.. T he .......................................................... 100 M edusa Portland Cement Co...................................................... 32 M epham , Geo. S.. & Corp............................................................ 93 Miles Mfg. C o.. . ..................................... -................................ 67 M ultiplex Concrete Mchy. Co............................................ 44-45 Xobte, T hos. W ............................................................................ 86 O lsen, Eugene F........................... .......................37-41 Incl. P o rtlan d Cement A ssociation............. 81 Price B rothers Company................................................................... Professional S e rv ic e .............................................. 86 Ransom e Concrete Mchy. Co.................................................... 55 Reed Co., R. F............................................................................... 87 Ricketson M ineral Color W o rk ? ................................................86 Roeth Vibrator Company 85 Rycrson. Jos. T., & Son....... ... . ....................... 93 Sasgcn Derrick Co.............. 97 Schaefer. Albert F .......................... ................. . . . 86 Scluvalbe. L E ......................................................................... 37-95 Sm all Co.. T. L............................... 76-77 S p e c ia ltie s .........................................................................................86 Stearns Mfg. Co. . . . . 37-41 Incl Sullivan Co.. The . . . . . ....................... 86 Swenson Pulverizers . . ................................... 98 T am m s Silica Co...............................................................................86 T ym stone S tu d io ....................................................................... 48-49 Universal Div of Consolidated Concrete Mchy. C orp................................................................................ 57-64 Incl. Union Steel Products C o ................................................................98 U niversal Form Clamp Co............................................................ 73 W appat, Fred W ............................................................................ 97 W avlite Company. T h e ............................................................ 67 W illiam s, C. K., Co...................................................................... 93 Spud Up Your Pre-Cast Concrete Joist Production with UNION CHAIR STIRRUPS W rCitoenfiotrraCctolmonplAetcecessorieso f UNION STEEL PRODUCTS CO. 418 N . B o rrlen 8 t . A lbion. M ich. SEE THIS ROLL CRUSHER At the Show in Booth L82 All Steel Construction . . . Dust T ight Roller Bearings . . . Small Diam eter Crushing Rolls SWENSON PULVERIZERS, Cherry Valley, III.