Document KJxdVyE2ZnxVbLNOg0QL2aXYN

CofVmtM, Onto Ttit (Mg field of stock-dust measurement ore being introduced. Fig. 1 pictures the operation of the Smokescope, as pre sented by J P Strange of the Mine Safety Appliances Co before the spring meet ing of American Society of Mechanical Engineers in Columbus, Ohio. It is aimed at removing criticisms to the Ringelmann method of measuring stack density, A reference-standard film disk H is viewed against the background next to the stack. Both smoke end reference film get light from the aame source. Then o lens in (he instrument projects o virtual image of the reference standard to a focal distance equivalent to that o( the stack. Then the eye can make ol truly realistic comparison. This system limks the field of vision to the stack area and eliminates stray light. Light from the area next to the stock passes through the reference film disk H, in the barrel B, to front-surface mir ror . This mirror, together with the lens F, platfea an image of the reference film on the image mirror, where you can compare it with the smoke as you see it through the apertures. The four densities corresponding to Ringelmann numbers 1-4 appear on (ho Imago mirror. Stack-Dust Loading. Fig. 3 Is a special Stack-duit loodlngs, bated on the Bituminous Coot Rossor&l table, below. It designed os a guide for boiler operate^' tasting arrangement developed by H C Bellman and his staff in the Smoke Regulation Dept of Columbus, Ohio. Oust lu Stack Gaos by Stoker Type, Buraluj Rata They estimate it takea a crow of two to three men two days to run a set of tests Grahi of dull per co ft got, 500 F; 12V CO, leering boDtr they can use In araoko-control work. The POWIB-PLANT STACK and connecting breeching usually hove no locllltio* for proper sampling and letting of stack gases Banting rota Ib/tq ft/hr Underfeed, chela end troveffeg-greta stoker Spread* sfeksr 20 re 25 25 re 30 30 re 15 35 re 40 0r 40 0.1 S to 0.21 0.2 te 0.4 0.4 to 07 07 te 1.3, 0.5 te M U te Note: To convert the above values to poeads of dust per 1000 lb of got adjusted to 12% COi multiply by ).. Ufc ettirwM, MOM t*t0 --I >. I Chort permitt o Hold opprotsol of stock loading for smoke-control purposes *' and translates results os*being within or either side of the ollowabte limits charts, Fig. 4, permit them to translate field data from the test setup directly to usable results right on the job. The usable results Bellman seeks are whether sn individual stack-emission role lies within or without the ordinance allowance, namely 0.85 lb per 1000 lb of due gas. fn fact, a reasonable mar gin of 0.15 lb, or roughly 17.59b, is per mitted so that If a stack tests out at 0.B5 lb per 1000 Ih of gas or under It's Field Testing of Stack-Dust Emission! Needs Simplifying approved; between 0.85 and 1.0 lb per 1000 lb, It's approved based on duplicate tests; over 1.0 lb per 1000 lb, and U'a disapproved. The only flaw Bellman finds is that few plants have reasonably long, straight runs of duct so vitol to Determining just when a plant stock goes beyond allowable air-pollution ordinances is a tough job for enforcement as well as plant men. Here are some of the latest field aids employed around the country for combatting this problem In recckt years, air-pollution con trol has been getting unusual attention in a largo percentage of our industrial arena. Along with it baa come legisla tion frequently spalling out allowable limits for smoka emission, either in den sity to the cyo or In actual stack-dust loading. But, unfortunately, the ac cepted methods of measuring these dis charges do not lend themselves to sim ple, indisputable checks that plant oper ators or enforcement agents can run. As o direct, practical result of this measuring weakness, air-pollution con- trol suffers. You'll find enforetnrt1 ordinances vary oil over the lot in lM way they identify a stack offense. Sea* employ the long used Ringelmann chtrt to deeide density, and let It go at thsi; others refer to the ASME Power Ted Code for dust loading. The Ringelmann chart, for exAtnph . has been shot full of holes because tb0*j] are so many outside influences thst betfi on Us readings. For example, the b*eM ground against which the stack is COD'! pared, the lighting variations, the ^ server's position, whether the d#J - bright or dull, the more than likely difImnees in light intensity on the chart i* contrasted with that at the stack---all eootribute to the doubts about the value e( the Ringelmann. ' The ASMS Power Test Cede, designed primarily for performance end occepability.tests of dust collectors, proves a ?*ry trying method of field testing for allowable stack-dust loading. .Many directly involved in smoke-con,ltol work hove been pushing to uneover seitsbte ye* cosily applied atock-meosur- leg devices. Along with these individual efforts there is a well-integrated testcode activity, sponsored by the ASTM Committee D-22 and numbering some 60 technical experts. Out of their ef forts may very well come the truly scien tific moans of properly evaluating stack discharge. Possibly (hey may even be able to convince the public as well as the enforcement agent that visible slack emission is no true measure of on indi vidual stack's contribution to a city's dust-fall problem. Density Meaiuromonts. fn the mean time, though, new developments in the accurate dust-load sampling. -Down In Louisville, Ky.f J C Marks, assistant chief, and R W Bourne, chief engineer of Jefferson County Air-Pol lution Control District, have worked up the chart In Fig. 2, bated on the table (facing page) from Bituminous Coal Research publication, Aid le Industry, 500*320. T1iis chart's soto objective 1s to acquaint the plant-operating man with the amount of dust he is sending out his stock under various firing rales, and how these amounts compare with the ordi nance recommendation, Fig. 2, ((no D. The rest is up to the operator. ENGINEERING AND MANAGEMENT SECTION w"il *UCUSt 1953 ENGINEERING AND MANAGEMENT SECTION 77