Document 5Ledjm4oqOb40bdD3MJnxJdQz

frluUL^cJ? UdoQ Cl--e ap of water-Jieketed eiftola showing wheel and ratehet for direetlan teao Jot Into molt. Koto that molten stream La split and blown Into eolleet* lac ehamher on rlfht Making a Finer liock Wool WaakeAa Lime and Stone Co. installs new cupula, and improves method of rock wool manufacture and preparation of bats ock wool manufacture has been out. Along with improved plant prac R more or leas in an evolutionary tice, the quality of the product has stage for the past two years atbeen continuously perfected. Waukesha, Wls., where the Waukesha The first attempt to make rock wool lime and Stone Co. built a plant in from limestone and other materials 1939. Out of two years' experience in the proportioning of raw materials available locally was an experiment. Compressed air was used to fiberize and in the melting and blowing of the wool in a local grey-iron foundry, wool, there has been developed a more which uses limestone produced by the efficient plant than the original lay company as flux. These experiments proved conclu sively that a good grade of rock wool could be manufactured from the ma terials at hand. Then the plant was built In 1939 and recently changes were Incorporated which have per fected the process. As built in 1939, the plant was typical of many others in operation. It had a vertical cupola, a blowing Roek wofl manafaHarliiif plaat, abowlas Mew eipola In the eenter with skip backet to eletate wheelbarrow load* of materials wklrk are welched oa scale Im tke foreground. Induced draft faa si) be seen to the left SEPTEMBER. .. Ull S3 MTC 017201 bucket. When all the ingredients are dumped, a cable hoist raises the skip to dump into the cupola through a chute near the top. Proportions of the feed material are such to approach an approximate analysis of 40 per cent SiO... 20 percent A1_,03, 20 per cent CaO and 20 percent MgO. Coke for the fire is a 4-in. special cupola lump, of high volatility and low in ash. It is also desirable to have sized feed materials that are free from fines, to facilitate the draft and to prevent segregation which would Geaeral view of rock wool plant. Storage tall4tng on left for finished wool lead to uneven draft conditions and irregular melting. Limestone is a uni chamber and a continuous conveyor equipped with cutting knives, to pro duce loose wool and granular wool and to make insulation bats. A new pre-fabricated steel building was erected for the purpose. This plant as built had developed^ capacity up to 11 tons of rock wool in 24 hr. The cupola was made from a 48-in. diameter boiler shell lined with ordinary fire brick, with cooling water sprayed constantly over the from 230 lb. an hour to 180 or 190 lb. A stoker to be installed is expected to reduce the coal required by an additional 25 percent. Another important saving has been made by pre-heating the blast air for combustion within the cupola. About 1200 c.f.m. of air is forced through the melting zone within the cupola by the Bailey fan. which has a capacity of 2000 c.f.m. formly sized 3-in. product from the commercial crushed stone plant. Slag is obtained in large chunks which are broken down by lifting them with a crane and dropping them to shatter. Average size used in the mix is 6-in. Quartzite is also of uniform size with out fines. These materials are mixed fairly well in handling and in the process of dumping into the cupola. Temperatures of the melt at dis charge from the cupola for blowing outside of the shell around the melt ing zone. Alternate layers of raw ma terials and coke were fed into the top of the cupola by a skip bucket and an air blast to support combustion was introduced through ports by a 30-in. Bailey centrifugal fan into the melting zone. A 75-hp. hand-fired boiler devel oped steam under high pressures to blow the wool into a collecting cham ber through nozzles of V-shaped sec tion. Capacities up to 12 tons in 24 hr. were arrived at by splitting the molten stream from the cupola into two separate streams, with steam from two separate nozzles fiberizing the material as it was blown into the collecting chamber. At the start, ca pacity was only five tons a day. I.pft: Fred C. Wolf. vlo*prenldei< and itenerai nperlnteaient Riffkt' riaroncr Wolf, hla on, aapfrlnlendenl of Ihr plant Redare Fael Caaramptlea By Plant Improvements In its entirety, the plant has not been changed much since it was built. However, the cupola has been re placed by a new one of like size that is water-jacketed, and in connection with the new cupola certain impor tant economies have been realized. This cupola consists of an unlined inner shell, fabricated of %-ln. fire box steel, with an outer shell made from Vi-in. boiler plate. Cooling wa ter is circulated between the two shells by one of the quarry pumps at the rate of 20 to 30 g.p.m. In the process of cooling the shell, the circulating water is heated to a maximum of 200 deg. F. and then be comes part of the boiler feed water. By using pre-heated boiler water, the plant coal consumption has been cut Waukesha Lime and Stone Co., principally a producer of crushed limestone, went into the rock wool business as another outlet for crushed stone. Its quarry contains limestone strata of varying chemical composi tion. By selective quarrying, lime stone for rock wool manufacture is gotten out that contains, on an av erage. 53.3 percent CaCO;l, 43.4 per cent MgC03 and 2.4 percent SiO._,. Other raw materials mixed in with this limestone are blast furnace slag for silica and CaCOt. a Portland quartzite for SIO;, and scrap glass when available locally to replace part of the quartzite. The slag averages about 75 percent SiO. and the quartzite 80 to 85 percent. Each material is weighed separately in a wheelbarrow on a Fairbanks scale and is dumped into a skip range from 2800 deg. F. to 3200 deg. F. Heat intensity is varied by adjust ing the volume of air forced through the bed in the cupola. Steam pres sures for blowing range from 85 p.s.i. to 110 p.s.i. to produce the most ideal fiber length and to still hold down the percentage of shot. Splitting the melt into two thinner streams for blowing is also helpful in eliminating shot. Each of the two steam nozzles is adjustable, through a wheel and ratchet, to change its direction up or down or laterally. Having this posi tive means of directing the steam jet into the melt is a detail in operation that has proven invaluable in the flberization process. Shot in the pro duct is very small and is well below permissible amounts by weight. The collecting chamber is very similar to those used in many other 54 ROCK PRODUCTS MTC 017202 Lefti Reiier compressing blanket as ft tarrirM from chamber. Roller height Is adjustable to *rj thickness and density of bats. An additional roller has been Installed sinee this picture was taken to further compress the blanket. Rtylili Showing: one of the rollers resting on wool blanket. Steam rising on the opposite side of conveyor Is from "hot" roller underneath plants, but the arrangement for cut ting bats Is highly perfected. Fibers of wool settle In a loose blanket In side the collecting chamber on a flat steel slat conveyor which is. In effect, a moving floor in the chamber. The chamber measures 16-. x 20-ft. in vertical section and is 60-ft. in length. Wool Is slowly moved out into the cutting and packing room on the con veyor as a continuous operation. The loose wool is compressed into a large blanket of desired thickness and density by adjustable rollers as it is conveyed toward the cutting knives. One of these rollers Is located where the wool emerges from the chamber and It also serves to seal the collect ing chamber. There are also two others at the far end of the conveyor. The conveyor has a variable-speed drive, consisting of a 3-hp. 1750 r.p.m. Allls-Chalmers motor with a 20.000:1 gear reduction. This drive and the up or down adjustment of the compress ing rollers are the means of regulat ing the thickness of the blanket and for changing from one thickness to another. Bats are made in 2- and 3 Vi-in. thicknesses measuring 15- x 24-ln. in size. At the far end of the blanket from the collecting chamber, the metal conveyor transfers to six short con veyors parallel to the length of the main conveyor. Over these belts, seven circular discs on a single shaft turn at a high rate of speed in a vertical plane between the six con veyors to slice off six 15-in. widths of wool. Edges trimmed off are put through a granulator. Granulated wool is sold in bulk. An automatic cross-cut saw of orig inal design is timed according to the movement of the main conveyor to cut the strips of wool into bats 24-in. long. It consists of a 22-in. circular B4 of etB?eyr showlif ali widths of bats coming to the operator* for bosiag. Note WMi-nt saw directly serosa table, ventilator hood In the background, nmd piles of trim, to the right, wblrb are granulated blade connected to the shaft of a 3-hp. reversible motor turning at 1750 r.p.m. A drive shaft is attached to and driven from the motor by chain and gears to support the en tire assembly on parallel gear tracks spanning across the conveyor. Twen ty-four inches of travel of the rock wool conveyor automatically trips an electrical contact and a clutch is en gaged automatically to the drive shaft at the proper motor speed to send the blade across the blanket of wool. Near the end of the gear track, a switch is tripped and the carriage is stopped by a spring bumper. The fol lowing 24-in. of travel of the con veyor sends the saw back in the other direction, with th motor turning in the reverse direction. Bats are packed in cardboard boxes holding 25-sq. ft. of the standard 4-in. bat. Loose wool is made by raising the compression rollers over the conveyor and is packed in cloth bags. About 60 percent of the production of rock wool bats Is made plain, the rest having a paper covering on one side. This paper has one sticking sur face and is threaded from a paper roll between the under side of the bats as they come off the conveyors and a roller which is heated through its length by live steam from within. The heat melts the gummed surface of the paper so that it will adhere to the wool. Loose rock wool is treated with lubricating oil to make It dustless, and various types of chemicals are used as binders. Among them are so lutions with bases of melted resin and creosote. These chemicals are blown Into the mass of fibers as the wool is blown Into the collecting chamber, but from a separate nozzle. SEPTEMBER, 1*41 MTC 017203 55 Fumes from the various chemicals are exhausted from the packing room through a hood over the wool blanket on the conveyor. The hood is con nected by a duct to a 2700 c.f.m. ex haust fan. Falire Improvements Since the original plant was built, a 52- x 82-ft. warehouse has been built, which will accommodate a week's run of the plant. A second roller near the first one over the con veyor has been installed, for further compressing, since the wool when first comparted tends to "spring" J back into its original loose state. | It is planned t- house-in the con- i veyor and to m ke changes to the , conveyor to dry le wool before cut- I ting it and then o cool it, first by a j blast of heated air and then by a j blast of cold air. Fans will force the [ air through the wool blanket on j the conveyor. This is desired in order to maintain a uniform product as shipped in boxes. Otherwise the low est bat in the box becomes com pressed and assumes a thickness that makes it too dense. g. HOW OLD IS YOUR DYNAMITE WHEN YOU USE IT? Waukesha rock wool is sold princi pally in the Milwaukee area and in nearby counties. The bulk of the sales are through insulating contractors. The plant was designed by Fred C. Wolf, vice-president and general su perintendent, and Clarence Wolf, su perintendent. Most of the equipment was built in the company's shops. Rock wool is just one of many pro ducts of the Waukesha Lime and Stone Co. The company has been in business for 36 years and has built its business on a policy of diversification. The products include sand and gravel, crushed stone aggregates: flux stone: paving and rip-rap stone; pulverized stone for agricultural stone and for asphaltic surfacing; "sealcote" stone, chips and screenings; poultry, chicken and canary grit; standard and nonsllp barn lime; terrazzo stone; hand cut random ashler veneer building stone; rubble stone; Io-Cal. a health building cow food which 1s an iodized tube-milled 200-mesh limestone and others. The company is headed by Mrs. M. O. Gillen, president and gen eral manager. Frequently lack of uniformity in blasting ii- Mamed on some alleged "unknown change in rook structure." supposed to have occurred behind ihe quarry face. Actually, in all probability, the REAL reason for the lack of uniformity in the shooting, is OLf) dynamite. Old, or stale, dynamite certainly can be inefhcienl. Moving ex plosives from the manufacturer's plant to his plant magazine, to his field magazine and from there to the t ustomer's magazine, usually means a period of as many as eight months. During this time it may be exposed to changes in temperature, humidity and the like, resulting in lessened strength and efferliyeness. NATIONAL explosives are shipped direct from our plant to the customer FRESH and 100/t efficient, within 12 to 4R hours after receiving the order. IFrite today for more information about Rational Explotim. Take advantage of our rears of practiral experience. NATIONAL POWDER COMPANY ELDRED, PENNSYLVANIA (MrKEAN COl'.VTYl Talc Industry Grsws Sales or talc, pyrophyllite, and ground soapstone reached another new high in 1940, exceeding the peak of 1939, by over 27,000 short tons. The total sales, as reported to the Bureau of Mines, were 281,375 short tons valued at 83.008,320, increases of 11 percent in both quantity and value over 1939. Sales of sill classes in creased in quantity and value, the greatest increase being in the sales of ground products. Eleven states reported sales of talc, pyrophyllite, and ground soapstone 'and a little pinite) in 1940 com pared with 1939. Eight of these states, located in the East, supplied 86 per cent of the sales: Western States ac counted for the remaining 14 percent. All time highs were again established in California, Georgia, North Caro lina, and New York. New York was by far the leading state, with Cali fornia, North Carolina, and Vermont of about equal importance, but each supplying only about a third as much as New York. Five industries -- paint, ceramics, roofing, paper, and rubber--consumed 75 percent of the talc, pyrophyllite, and ground soapstone of domestic origin. The paint industry--the lead ing market for these materials--took only 24 percent of the total sales in 1940 as compared with 27 percent in 1939. The ceramic industry increased its hold on second place, while rubber dropped to fifth place in 1940 after being tied with the roofing and paper industries for third place in 1939. 58 ROCK PRODUCTS MTC 017204