INDUSTRIAL AND ENGINEERING CHEMISTRY Strisorver, E., Chaikoff, J., and Weinman, E., J . Biol, Chem., 192,453-63 (1951).
Stroh, G., U. S.Patent 2,586,882 (Feb. 26, 1952). Suzuki, T., Hagwara, F., and Kubota, NI., Japan. J . Pharm. & Chem., 23, 191-3 (1951). Ibid., pp. 246-7. Swietoslowski, IT., Przemysl Chem., 29, 6,41-3 (1950). Tabor, H., and Hayaiski, O., J . B i d . Chem., 196, 171-5 (1952). Tabor, H., Mehler, A., Hayaiski, O., White, J., Ibid., 196, 1218 (1952).
Thomas, H. C . , J . Chem. Phus., 19,1213 (1951). Thompson, J., Power, 96, 108-9, 220 (May 1952). i372) Tiselius, A., Endeavour, 11, 5-16 (1952). (373) Todes, O., and Bikson, Y., Doklady Aicad. N a u k S.S.S.R., 75, ,
727-30 (1950). (374) Tofima, S., and Kasaka, Y . , J . Electrochem. Soc. ( J a p a n ) , 18, 363-6 (1950). (375) Tonake, U., Japan. Patent 178,608 (April 1949). (376) Topp, N., Science Progr., 39, 640-57 (1951). (377) Topper, Y., and Stetten, D., J . Biol. Chem., 193, 149-55 (1951). (378) Trail, H., T;. S.Patent 2,573,743 (Nov. 6, 1951). (379) Tunitskil, N., and Cherneva, E., J . Phys Chem. (S.S.S.R.), 24, NO. 11, 1350-60 (1950). (380) Tyler, R., Moshe, W., and Westin, M., Sewage and I n d . Wastes, 23,1032-5 (1951). (381) Uezuki, S., Japan. Patent 180,531 (October 1949). (382) Ibid., 173,576 (September 1951). (383) Ulmer, R., and Caro, P., Sugar, 47,46-8 (1952). (384) Ulrich, W., &err. Apoth. Ztg., 6 , 7 7 4 (1952). (388) Underwood, G., and Deatherage, F., Science, 115, 95-6 (Jan. 25, 1952). (386) Vajna, S., Magyar K h .Folioirat, 56, 88-96 (1950). (387) Vajna, S., and Pechler, E., Acta. Chim. Acad. Sei. H u n g . , 1 , 196-206 (1951). (388) Van der Flies, G., Chem. Weekblad, 48, 380-5 (1952).
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Vankataranisknan, K., Kreshnaswary, N., and Romaknishnan, T., I n d i a n J . Med. Research, 39,211-17 (1951). Venkatasabrahanianian, T., and De, S.,Science and Culture (India), 17, 180-1 (1951).
Vermenlen, T., and Hiester, K., IND.ENG.CHEX.,44, 636-51 (1952).
Vines, S., U. S.Patent 2,579,283 (December 1951). Voyles, C., and Orgain, E., N e w Engl. J . Med., 245, 808-11 (1951).
Waldock, K., and Frizzell, L., J . Phys. Ckem., 56, 654-7 (1952).
Wall, F., Ondryein, J., and Pikramenon, M., J . Am. Chem. S O C . 73, , 2821-5 (1951).
Weil, H., Chimica e industvia ( M i l a n ) , 33, 287-94 (1951). ;CVeiss,9.,and Hofmann, U., 2. Naturforsch., 66, 405-9 (1951j. Werner, L., and Perkman, J., J . Am. Chem. SOC.,73, 5215-17 (1951).
Wheaton. R.. and Harrineton. D.. IND.EXG.CHEM.. , 44., 1796800 (1952):
Whittaker, D., and Allen, G., Brit. Patent 666,410 (Feb. 13, 1952).
Whittaker, D., and Allen, G., U.S.Patent 2,588,784 (March 11, 1952).
Wiklander, L., Acta Agr. Scand., 1, 190-202 (1951). Wilkes, F., Corrosion, 8, 1-2 (June 1952). Williams, K., and Bevennue, A , , J . Assoc. Ofic. A g r . Chemists, 34,817-21 (1951).
Wirth, L., Southern P u l p Paper M f r . , 14, 14-18 (Oct. 15,1951). Wood, J., Ferguson, D., and Lawrence, P., J . Am. Med. Assoc., 148, 820-4 (March 1952). Wood, IT,,U. S.Patent 2,600,719 (June 17, 1952). Wyeth, Inc., U. S. Patent 2,584,158 (Feb. 5, 1952). Yamamura, T., and Nomiyana, Y . , Japan. Patent 181,089 (Dec. 7, 1949). Yufera, E., Rea. cienc. apl. ( M a d r i d ) , 5, 216-34 (1951). Zeegers, J., Chem. Weekblad, 48, 356-61 (1952). Zimmermann, RI., Angew. Chem., 64, 107-10 (February 1952). Zinner, H., Chem. Ber., 8 4 , 7 5 0 4 (1951).
RICHARD L. SPEAKER
71 17 NORTH LONGACRE RD., MILWAUKEE 11, WIS.
This year a great deal of literature appeared on the use of belt conveyors for long-distance transmission ofbulk material. There were several new devices to aid handling of material in bins. Production line conveyors began to realize their potential by adopting automatic control and coordination. Textbooks and films show promise of introducing a much-needed technical approach to this subject.
2. The material can be supplied and 3. consumed The operation continuously* continues long enough to offset the high initial cost. 4. The distances traveled are not too great (within 10 miles
T
or so). Special conditions may, of course, justify belts under other circumstances-such as those surrounding the proposed Riverlake belts spanning 103 miles across Ohio.
Belt conveyors are winning economic battles against railroad haulage, trucking, earth movers, and tractor-trailer trains. This trend seems to have received its greatest impetus in solving the problem of aggregate removal for construction of the huge government dams of the last decade-Grand Coulee, Shasta, Hungry Horse, etc. These conveyors, carrying aggregate from gravel supply stations up to 10 miles from the dam site, proved able t o reduce haulage costs spectacularly, After the jobs were completed, the contractors found i t possible to reaell the components of the conveyors for a further tidy profit. NaturaLly, the reason for this popularity is that the particular application is peculiarly well adapted t o the economics of belt conveyor haulage. Belts are most easily justified where: 1. The material is nonfriable and otherwise suitable for handling on belts.
Belts are used extensively in coal mining (WT), in spite of thefact that undesirable degradation in the coal occurs at transfer pointe. Apparently other handling methods available produce equivalent product damage. Improved belt strength would reduce this disadvantage. The maximum possible length of a n individual flight is limited by the tensile strength of cotton fabric in ordinary belting. When this maximum length is reached, the commodity must be transferred to another belt, with consequent possible degradation of the material. The maximum length has been sharply increased in recent years by the introduction of a steel cable fabric in place of the cotton fabric (26). This important development has permitted the installation of a single conveyor extending over 2 miles from a coal washery to a barge loading station at the Wierton Mine near Morgantown, W. Va. (36). It has also permitted a single coal mine belt operating a t 18’ incline to extend to the surface from a depth of 860 feet below ground (26). Because they have negligible stretch, steel cable belts are also being specified where dimensional stability is important.
HE Rise of the Rubber Railroad” is not only the title of a very complete and accurate digest of the economic and engineering aspects of long overland conveyor systems (db), but it also aptly describes the direction and motivation of the belt conveyor industry today. BULK-HANDLING CONVEYORS
January 1953
INDUSTRIAL AND ENGINEERING CHEMISTRY
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COURTESY QOOOYEAR T I R E & RUBBER EO.
Graphic Comparison of World's Highest Coal Belt Lift
Another development recently announced in England (39)insplit tube with low pressure air maintained in the lower half of troduces an entirely new tension principle. It incorporates two the tube separated from the commodity by a permeable sheet. driven steel cables carrying the tensile load, with an ordinary Seepage of air serves to keep the pulverized material fluidized single-ply cotton belt supported between them to support the while it follows a gravity flow. The design has been adapted commodity. One installation successfully operating in Scotland successfully to a self-unloading steamship ( 1 9 ) . is 2361 feet long and incorporates a rise of 572 feet. Designers Another recent development in pneumatic conveying involving claim that lengths up to 3 miles and lifts to 3000 feet are possible. air activation introduces the necessary air volume through a This construction has the additional advantage of replacing primary pressure vessel (43). Blasts of compressed air are incostly belt idlers with simple sheaves for the steel cables, with no jected into the loaded pressure vessel intermittently through a separate support whatsoever for the belt. No installations of cone a t the base. As the air rises through the material, fluidizathis type have thus far been reported in this country. tion occurs, and the mass follows the line of least resistance A further advance toward the goal of longer belts, which is rethrough the pipes in a fluid flow pattern. Materials such as ported to be under development, is the introduction of intermecement have been carried through pipes over 3000 feet long indiate drive stations on the single flight (92). If this development corporating a 3OO-foot rise. The air requirements are claimed t o proves practical, there would appear to be no limit to the possible average less than 1 cubic foot per pound of material. The calength of a single-flight conveyor. pacity of the system is limited by the batching schedule to about For some applications requiring resistance to heat, glass-fiber1000 cubic feet per hour. rubber belts have proved satisfactory (16). This belt has been A full issue of one of the materials handling trade journals has used successfully to carry hot fine chemicals up to 530' F. It is been devoted to a comprehensive discussion of all the problems not recommended for glowing, heavy lumps; nor is it very reof bulk materials handling and some proved solutions (18). sistant t o abrasion. For serviceat temperaturesexceeding500° F., steel or wire mesh belts are usually chosen. A belt turnover system has been developed to overcome probBULK HANDLING IN BINS lems in handling wet, sticky, or freezing materials. The system permits the clean side of the belt to contact return idlers, thus The problem most frequently encountered when using bins for preventing abrasion, corrosion, and buildup on idlers (94). storage of bulk product arises in the failure of the material to disThe well known screw conveyor principle has been used as the charge readily by gravity through the restricted opening. This basis for a new design of problem presents itself with heat exchanger (62). The many types of products. screw blades are hollow, Several d eve1 o p m e n t s and carry the heat exhave been announced in change medium past the connection with the flow of material, as they rotate, bulk materials through bins, producing a very high coefTwo companies have anficient of heat transfer. The nounced improved bin-level screws may be used singly to indicating devices (12, 47). convey material whose temProper discharge from bins perature must be carefully has always been a serioua controlled, or they may be problem, and several types mounted in groups to form of bin-discharging devices a heat exchanger. have been in common use Noise-free, dust-free (Figure 4). High-frequency movement of pulverized vibrators have been very material has been achieved successful in maintaining in a cement plant through movement in dry materials the use of air-activated of relatively high bulk gravity conveyors, utiliEing density. Aerating devices the principle of fluidizing have been able to induce COURTESY STANDARD CONVEYOR CO. AND WAUKESHA MOTOR CO. the solid mass. The mass fluid flow in low-density flows through a horizontally Figu!e I. Conveyors for Packing and Shipping Small Parts bulk materials. However, ~~
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a smoother and more economical flow has resulted (Figure 1). The automatic factory of the future will require the full integration of materials handling equipment with production facilities. That this is not only foreseeable but has actually already been achieved in some instances is the subject of one complete issue of a leading trade magazine ( 1 7 ) . One of the plants discussed is Ford’s new Cleveland engine plant. This plant appears to offer striking evidence of the approaching reality of automatic factories, for in many instances parts are carried through all machining operations without manual attention. More particular studies of individual operations in this plant are made Blsewhere (2-4). The full use of conveyors in a plant producing thousands of varieties of small machine parts would be considered an absurdity by some. Nevertheless, the Elgin plant of Shakeproof Screw ha? not on11 achieved this, but has retained the necessary flexibility in this new plant, where production costs are a fraction of previous costs. Wicks describes in detail the layout provided to accomplish this effcct ( 5 3 ) . h conveyor system planned for straight-line flow often introduces bottlenecks in cross traffic. Iieller ( 3 3 ) describes a number of techniques for safely avoiding this difficulty. Practically all foundries of any size have turned to mechanized handling of sand, molten metal, molds, and castings Winter3 (65)describes the type and function of the various conveyors: in one of General Electric’s plants, and it appears to be typical of the efficient layouts becoming common in this progressive industry.
COURTESY FOOD MACHINERY CORP.
Figure 2.
Automatic Milk Case Stacker
there are many types of materials which do not lend themselves to treatment by either of these methods. Systems involving viscous materials, colloidal dispersions, liquid matrice?, and materials tending to cake or freeze might fall in this class. The development of a large-amplitude pneumatic displacement panel (Figure 5 ) promises to offer a solution in many of these and other cases (23). I n dry material, it establishes interparticle movement by transmitting its displacement throughout the mass. With viscous materials, it exerts an extrusion effect. Caked materials are subjected to the hydraulic force due to the large displacement. Installations have shown that these units can successfully withstand the abrasion of direct contact with the bulk ingredients. A thorough discussion of the comparative merits of vibrators, aerators, and displacement panels, as applied to various types of material, is presented by Davis and Pottberg ( 1 4 ) . A mechanical bin discharger offers still another solution to the problem (48). It would appear t o be the most positive solution of all for breaking up caked material, but a t the same time would obviously be the most expensive and require the most maintenance. The manufacturer of this bin discharger also offers a new bin-closure valve consisting merely of a rubber sleeve which is twisted to close, and thus is nonclogging, even on the lumpiest material (49). PACKAGE CONVEYORS
While rubber railroads and conveyorized subways (45)have provided glamor for the industry, package-handling conveyor systems have prosaically continued to contribute economy and efficiency to modern mass production techniques. Wherever conveyorizing between production operations has been accomplished,
OOURTESY CRESENT TRUCK C O .
Figure 3.
Side-Shifter for Fork Lift Truck
The handling of milk cases through storage and shipping areas has been facilitated by a system developed in a California dairy (20). -4n automatic case stacker feeds cases in stacks of 5 on to chain conveyors set into the floor, arranged in the storage rooms so that cases need not be rehandled, although stacks of 5 may be removed with cargo hook to adjacent dead storage (Figure 2). The use of conveyors and fork trucks in air freight handling at Kelly Air Force Base is ‘described by Campbell. Small items weighing from a few ounces up to 1000 pounds are unloaded from planes via portable poxer conveyors, then palletized inside the
INDUSTRIAL AND ENGINEERING CHEMISTRY
January 1953
warehouse. Larger articles are transferred on fork trucks, or, in rare cases, manually (9). Teamwork between fork lift trucks and conveyors is the key to economical handling of tin plate at the Baltimore plant of a large can company. By installing an automatic lowerator between floors rather than have trucks traverse the freight elevator, unloading time was cut from 30 to 10 minutes per truck (32). An illustrated resume of many proved methods of drum handling is given by Wilcox (54).
91
A new electric industrial truck for use in crowded areas has been announced (7). Another manufacturer announced a side-shifter attachment (Figure 3) which seems especially valuable when used with a short truck in narrow aisles (13). A new towing attachment for heavy-duty fork trucks makes i t possible to use the truck for moving and spotting semitrailer trucks (10).
MONORAILS AND HOISTS w
*
No new products have come to the attention of the author but in this area, as in others, interesting applications have been announced. One system is described incorporating an automatically dispatched carrier for transporting boxes of bobbins between widely spaced buildings in a textile mill (11). The use of overhead monorail and hoist equipment in heavy machinery assembly has been well recognized. Haigh gives a description of one application at the new Caterpillar plant in Peoria (18). FORK TRUCKS
Many novel and useful attachments for fork trucks have been made available over the past few years (40),but one device developed for the textile industry is new this year. Koroskys describes the development and application of a wool-handling attachment which successfully and economically transfers loose wool between blending operations (34). Previous note has not been made of the Traveloader, a gaspowered industrial truck with forks mounted in such a manner as to permit lengthwise carrying of long material. This unit is now available in 5000- to 15,000-pound capacity (36). .4 well-known tractor manufacturer is now in production on a crawler-mounted fork lift said to bring the possibilities of palletized handling to areas heretofore impossible to traverse (5).
COURTESY OEROTOR M I Y CORP.
Figure 5.
Pneumatic Panels Aid Bin Discharge
A comprehensive program for training lift truck operators ie presented by Holm (30). The importance of a n adequate training program is brought out by the example of costs incurred in one company over a 20-month period-a loss due to accidents and damage of 8110,000! PNEUMATIC TUBES
Pneumatic tubes, one of the earliest forms of conveying equipment, are coming into greater favor in industrial plants than ever before. Increasing rates of production have demanded faster processing of paper work. The first installation in this country of an automatic dispatching tube system at Bridgeport Brass is described (16). The system is too new to produce any figures on maintenance costs, and initial costs a t this time are high; but the possibility of serving many stations from a single circuit is a challenging one and should produce much interest in this development. A somewhat simpler and cheaper system allowing automatic dispatch through a single loop is also available, but i t permits only one carrier in the circuit a t a time, which, in the average system, would limit the capacity to about 3 carriers per minute (46). PALLETS AND UNIT LOADS
COURTESY STEPHENS-ADAMSON MFO. CO
Figure 4.
Circular Bin Discharger
Little success is reported in the efforts to secure favorable freight rates for returning pallets, so the emphasis in unit loading has shifted to the possibility of removing this necessity-Le., using nonreturnable pallets or no pallets at all. Since all of these methods also reduce the outboard weight, additional incentive is provided. Expendable fiber pallets have been used successfully to handle strapped, reinforced loads up to 4000 pounds (1). The use of fiber pallets requires not only careful study of all conditions, but in some cases necessitates testing for common carrier approval under the auspices of the Consolidated
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INDUSTRIAL AND ENGINEERING CHEMISTRY
Freight Classification ( 4 1). However, where their use has proved acceptable, notable savings have been achieved. The Pul-pac and clamp-type fork truck attachments, both eliminating the need for conventional pallets, continue to gain popularity but again, the application must be completely studied. Some companies have found it possible, by an ingenious arrangement of stacking pattern and folded fiber interlayers, to form a unit load which can be handled by ordinary fork trucks ( 2 1 ) . A glue applicator is available ( 4 4 ) which can be installed in a conveyor line for applying just the right amount of glue to containers to assist in holding them in unit loads. Savings in materials handling costs have been made a t T e s t inghouse Air Brake since the adoption of unit load principles and other standardization techniques according to Eyler ( 1 5 ) . Hyler explains the general application of unit load principles to a wide range of products (81). The unit load pattern of handling is ideal when fork trucks are available to serve each point where the load must be transferred. Haynes ( g 9 ) suggests that unit loads can still be considered if a pallet dolly is introduced to move the pallets short distances (such a6 inside refrigeration cars) where fork trucks dare not travel. Many products stored on pallets cannot be tiered unless racks are provided. An economical means of achieving a rack effect consists of pipe posts and sockets which attach to pallets to convert them for racking (42). Self-aligning nesting cups and sockets simplify stacking. INCIPIENT T H E O R Y
It is encouraging to note that courses and seminars in materials handling are beginning to appear in trade schools and colleges. This trend is sure to develop some of the theoretical treatment which the subject so sorely needs. Several text and reference books have been announced this year. Stocker (50), Apple ( 6 ) , and Barker (8) provide general elementary texts; Terborgh ( 5 1 ) offers sound criteria for developing an equipment replacement policy; and Mallick and Gaudreau ( 3 7 )offer a n advanced text on plant layout in which the sections on materials handling offer practical instruction for analyzing problems. A thorough education is possible through use of the many films which have been produced by manufacturers on this subject. A complete bibliography of these films is available (58). LITERATURE CITED
(1) Addison-Semmes Corp., Racine, Wis., “How to Save on Han-
dline Costs.” (2) Am. Machinist, 135 (March 17, 1952). (3) Ibid., 134 (April 4, 1952). (4) Ibid., Special R e p t . 312 (June 23, 1952). ( 5 ) American Tractor Corp., Churubusco, Ind., release on fork truck. (6) Apple, James, “Plant Layout and Materials Handling,” New York, K. Y . , Ronald Press, 1951. (7) Automatic Transportation Co., Chicago, Ill., advertising release on truck. (8) Barker, Footlik, Yerham & Carle, “Industrial Materials Handling,” Cleveland, Ohio, Lincoln Extension Institute, Inc. (9) Campbell, I. E., Mech. Eng., 74, 120 (February 1952).
Vol. 45, No. 1
Clark Equipment Co., Battle Creek, Mich,, advertising release on towing attachment. CleGeland Crane Graphic, 8 , 2 (1952).
Convair Corp., 4156 Library Road, Pittsburgh, Pa., bulletin on Bin-Vue. Crescent Truck Go., Lebanon, Pa., release on side-shifter attachment. Davis, E. A,, and Pottberg, Rolfe, Mech. Eng., 74, 245 (March 1952).
1
(29) i30j (31) (32) (33) (34) (35) (36) (37) (38)
Eyler, M i l l an.d Factory, 49, 103 (December 1951). Factory Management and Maintenance, 109 (October 1951). Ibid., 110 (April 1952). Flow, 7, full issue (June 1952). Ibid., 82 (September 1952). Food Machinery and Chemical Corp., Packing Equipment Division, Riverside, Calif., bulletin on case stacker. Footlik, Irving, discussion before Milwaukee meeting of American Materials Handling Society, February 1952. Fortune, 43, 121 (April 1951). Gerotor May Corp., Baltimore, Md., bulletin describing PnueBin. Goodrich Co., B. F., Akron, Ohio, bulletin on turnover belt system, 1952. Goodyear Tire and Rubber Co., Akron, Ohio, bulletin on steel cable belts. Goodyear Tire and Rubber Co., Akron, Ohio, personal communication on glass fiber belts. Goodyear Tire and Rubber Co., Akron, Ohio, bulletin on CoalFlo belting. Haigh, M. W., ?dachinery, 59, 183 (September 1952). Haynes. D. 0.. Modern Materials H a d l i n a (July 1962). Hoim. D. R.. Mech. Ena.. 74. 568 (July 1652). Hyler; J. E., M i l l and &tori, 50 (January 1952). I r o n Age, June 26, 1952. Keller, H. C., Sufety Maintenance and Production, 103 (February 1952). Koroskys, M. J., Teztile WorEd, 102, 124 (June 1952). L i n k Belt News, 19, 1 (March 1952). Lull Mfg. Co., Minneapolis, Minn,, advertising release on Traveloader. Mallick, R. W., and Gaudreau, A. T., “Plant Layout Planning and Practice,” Sew York, John Wiley &. Sons, 1950. Modern Materials Handling, 7, bibliography of movies (January 1952).
(39) (40) (41) (42) (43) (44) (45) (46) (47) (48) (49) (50) (51) (52) (53) (54) (55)
Ibid., 62 (September 1952). I b i d . (October 1952). Modern Packaging (April 1951).
Paltier Corp., Michigan City, Ind., bulletin on rack systems. Robinson Air-Activated Conveyor Systems, 205 South 42nd St., New York, B u l l . 313. Sage Equipment Co., Buffalo, N. Y., advertising release on gluer. Sollenberger, R. C., Am. Engineer (September 1952). Standard Conveyor Co., Sorth St. Paul, Minn., personal communication to the author. Stephens-Adamson Mfg. Co., Aurora, Ill., bulletin on bin level indicator. Ibid., Bull. 250, circular bin discharger. Ibid., bulletin on Twist-ite valve. Stocker, Harry, “Materials Handling,” New York, PrenticeHall, Inc., 1951. Terborgh, Geo., “Dynamic Equipment Policy,” New York, N. Y., McGraw-Hill Book Co., 1951. Western Precipitation Corp., Los Angeles, Calif., bulletin on “Holo-Flite processor.” Wicks, R. M., American Machinist, 95 (November 26, 1951). Wilcox, R. H., M i l l and Factorg, 50, 92 (March 1952). Winters, P. P., Materials Handling Engineering, 3, 93 (September 1952).
