Screw Conveyors Manual

CONTINENTAL CONVEYOR & MACHINE WORKS LTD.470 St-Alphonse Street EastThetford Mines, Quebec.Canada G6G 3V8Tel. (418) 338-4682Fax: (418) 338-4751www.continentalconveyor,caCONTINENTAL CONVEYOR (ONTARIO) LTD.100 Richmond Blvd.Napanee, Ontario.Canada K7R 383Tel. (613) 354-3318Fax: (613) 354-5789www.continentalconveyor.caCOPYRIGHT CONTINENTAL CONVEYOR. 19863468242627293135363738IntroductionForewordDesign DataSelection ProcedureBearing RecommendationsSpecial Applications and SpecificationsComponent Selection and Layout DataMaterial Input and DischargeScrew FeedersInclined Screw ConveyorsVertical Screw ConveyorsDrive Assemblies and ArrangementSpecial Fabrication Materials40485357636972788284Conveyor ScrewsShaftsHangersTrough EndsEnd BearingsSealsTroughsDischarges and Slide GatesTrough CoversTrough Cover Fasteners86878890929596Installation and MaintenanceAssembly BoltsFlange Bolt PatternsWeights and DimensionsEngineering InformationComponent Code IndexIndexIt is with great pleasure that Continental presents this ScrewConveyor Catalogue and Engineering Manual which covers ourcomplete line of screw conveyors and accessories. The informationcompiled in this manual is the result of many years' experience in thedesign and manufacture of bulk material handling equipment and isthereby your assurance of the best in both equipment andrecommendations.With the help of this manual, the screw conveyor user is givensufficient design information with which to effectuate a sound selectionof both single components and complete screw conveyors alike. AllContinental screw conveyors and components are designed and built inaccordance with the standards established by the industry and aretherefore completely interchangeable with equipment of otherrecognized manufacturers.Continental's production facilities have also kept pace with inherentadvancements in design. Numerous specialty machines have beendesigned and methods have been devised that help assure and controlmanufacturing tolerances, thus providing for interchangeability of parts,greater ease of assembly, smoother operation and longer life.We sincerely hope that you will find this manual complete in detail,easy to use and extremely helpful in fulfilling your screw conveyorrequirements.[~~;I~~~~ i n an ta 1.13FOREWORDThe basic principle of the screw conveyor remains unchanged todayfrom when Archimedes first used an internal type helix to remove waterfrom the hold of a ship. With the technological innovations of the pastcen.tury and a great deal of research in the field, screw (::onveyors havebecome precision pieces of equipment that can move materials eitherhorizontally, on an incline or vertically. They can be used as feeders,distributors, collectors or mixers and can be equipped to either heat orcool while performing the task. With proper covers and gasketing theybecome weatherproof, dust tight and rodent proof. Their compact designallows them to fit easily into restricted areas that would otherwise beunsuitable for most types of bulk material handling equipment. They aresimple to install and support and require very little maintenance. Per foot,they are undoubtedly one of the most economical types of bulk materialhandling equipment available today.41Ci:1 continantaljDESIGN DATAEngineering and LayoutThe following section contains all relevant information and basicengineering data that is required for specifying and designing theimportant features of most screw conveyor installations andapplications. There will, however, be instances when the informationherein will be insufficient with which to effectuate proper design due touncommon variables that may be present. Continental staff andengineers have considerable knowledge in the design of screwconveyors for special applications and will gladly assist you with soundsuggestions and recommendations for your particular problem.Conveyor CapacityThe capacity of a screw coveyor is dependant upon three principlefactors, namely conveyor diameter,. trough loading and speed.By changing one or all of these variables one ultimately varies theamount of material per hour the conveyor will handle. A small diameterconveyor will therefore handle the same amountof material per hour as alarge one by either increasing the speed of the small one or byaugmenting the trough loading. It is important to remember however thatwhen taken to extremes, this can bring about undesireable effects as anoverfull conveyor can become inefficient and one that turns excessivelyfast will subject the components to more rapid wear.When deciding upon trough loading, it should be taken as a generalguide that the less abrasive and more free flowing a material tends to be,the fuller the trough may be. Conversely, the more abrasive and sluggisha material is, the less the trough can be filled to allow it to work efficiently.Therefore, non abrasive, free flowing materials can be conveyed withtrough loadings of 45% while abrasive and sluggish materials requirelower loadings of either 30% or 15%. Exceptions to this rule occur when 8screw conveyors are used as feeders. This is dealt with further on in themanual.6Material AnalysisThe initial step in engineering a screw conveyor is to analyse thematerial being handled and ascertain its physical properties in order thatthey may be thoroughly evaluated and understood prior to proceedingwith the conveyor sizing and selection. These properties are discussed infurther depth below.Lump Size: The minimum diameter of a conveyor screw for a givenapplication is determined by the maximum lump size of the materialbeing handled. For this reason, it is necessary to thoroughly analyse thematerial and determine its maximum lump size and the percentage oflumps to total volume along with the minimum particle size and screenanalysis when possible. With this information, proper conveyor sizingcan be effectuated.Flowability: The flowability of a material greatly affects thehorsepower requirement of the conveyor in question. Flowability isrelated to the angle of repose of a material and therefore, fine free flowingmaterials can be handled at higher trough loadings with lowerhorsepower requirements than coarse, sluggish ones. Please refer to theClassification Code, Table 1 for further information.Abrasiveness: The more abrasive the material being handled, thegreater the wear the conveyor components are subjected to. For thisreason, it is necessary to determine the abrasive quality of the material inquestion prior to sizing the conveyor. Abrasiveness can be determinedby knowing a material's hardness on a Moh's scale and should this not beavailable the material can be compared with another known abrasivematerial.Special Applications: These are additional factors which can affectthe operation of the conveyor and are further discussed in the sectionentitled Special Applications and Specifications appearing on pages 26and 27 inclusive. 'Moisture Content: Material moisture content is also a factor thataffects material flow. Excessively dry or wet products tend to flow easily,however, many develop sluggish characteristics when having a moisturecontent between the two extremes. This is not accounted for in thematerial tables which follow and such materials should therefore bereclassified.Duty Cycle: Machinery design also includes selection of the properequipment for the usage it will receive. A conveyor operating for 2 hoursper day does not require the same heavy construction as one designedfor 24 hour usage. This appliesto material thickness and drive sizes alike.Likewise. shock loads to which the equipment and drive are subjected toare an important consideration. Treatment of these factors are notdescribed in suitable enough depth here. however, as previouslymentioned. our engineering staff will gladly assist you to determine thebest conveyor design.SELECTION PROCEDURE1. Establish Known FactorsThe initial step in engineering a screw conveyor is to analyze thephysical characteristics of the material, the rate at which it is to behandled and the distance over which it is to be conveyed.Screw conveyor capacity is defined in terms of cubic feet per hour.This must be determined in terms of the maximum capacity that is to behandled. This capacity is often stated in terms of tons per hour or poundsper hour. In order to change this to cubic feet per hour one must dividepounds per hour by the density in pounds per cubic foot. In some casesthe material density may vary for the product being handled. Thus, whencalculating the capacity of the conveyor, it becomes necessary toestablish the maximum capacity in pounds per hour and divide this by theminimum density of the material. This will give the required capacity ofthe conveyor in cubic feet per hour.2. Classify Your MaterialMaterials are classified as per the Material Classification Codeappearing in Table 1. It is from this that Material Characteristics, Table 2is compiled. When classifying a material, first look it up in Table 2. If yourmaterial is not listed, it can classified by comparing it with similarmaterials that do appear in Table 2 or by referring to the MaterialClassification Code, Table. 1.TABLE 1 MATERIAL CLASSIFICATION CODEABCDESIZEVery fine. 100 mesh and underFine. -1/8" mesh and underGranular, -1/2" and underLumpy, Containing Lumps over 1/2"Irregular, Stringy, Interlocking, Mats TogetherVery free FlowingFree FlowingAverage FlowabilitySluggish1234FLOWABILITYNon-abrasiveAbrasiveVery Abrasive567ABRASIVENESSFGHJKLMN0pQRSTUVWXyZMISCELLANEOUSCHARACTERISTICS(sometimes morethan one mayapply)Builds Up and HardensGenerates Static ElectricityDecomposes -Deteriorates in StorageFlammabilityBecomes plastic or tends to softenVery dustyAerates and develops fluid characteristicsContains explosive dustStickiness -AdhesionContaminable, affecting use or saleabilityDegradable, affecting use or saleabilityGives off harmful fumes or dustHighly corrosiveMildly corrosiveHygroscopicInterlocks or mats togetherOils or chemical present -which affect rubber productsPacks under pressureVery light and fluffy -may be wind sweptElevated Temperature8TABLE 2MATERIAL CHARACTERISTICS4514-2241-4310-1527-3028-3045-5050-6055-653565457-157-1513-20A35845WYC25815NC35QC35Q835U825827MYA27MY037835E45VE45VC35A17MC35SC25A45FRSA35NTUC35FOTUA35C45Y665566658886666865666666587677776656576666665875655565656.5.6.5.4.9.9.61.41.81.62.01.71.2.81.41.8.81.0.71.31.01.61.0.81.21.02.03.02.53.04.060-1204945-5845-5245-6245-5815100-120308120-4010535-4535-4045-5045-50A35RA25R037RE46XY835C46TY046TC46T046TC45E45RVXY825A35A25036A35XA45RE45TVY835C35C35825N827036825835WC15WC15C25045XA25MXYA45R045U457-1030-4540-5540-55120-180120-1807210-2024-38312836-4880-10575-856835-4036486034-4050-60562.01.51.4.6.62.62.01.62.0.4.4.4.51.82.51.8.8.5.5.81.2.7.6.62.02820201A20201A2A3030302020201A.303A.1A-3A.301A-20202030201A-303030301A-2A-1A-1818302020301A-1A-1A-1A-3030201A-1A-1A-1A-20201A-1820Adipic AcidAlfalfa, MealAlfalfa, PelletsAlfalfa, SeedAlmonds, BrokenAlmonds, Whole ShelledAlum, FineAlum, LumpyAluminaAlumina, FinesAlumina, Sized or BriquetteAluminate Gel (Aluminate Hydroxide)Aluminum Chips, DryAluminum Chips, OilyAluminum HydrateAluminum Ore (See Bauxite)Aluminum OxideAluminum Silicate (Andalusite)Aluminum SulfateAmmonium Chloride, ChrystallineAmmonium NitrateAmmonium SulfateAntimony PowderApple Pomace, DryArsenate of Lead (See Lead Arsenate)Arsenic Oxide (Arsenolite) *Arsenic, PulverizedAsbestos, Rock (Ore)Asbestos, ShreddedAsh, Black GroundAshes, Coal, Dry, -V2"Ashes, Coal, Dry, -3"Ashes, Coal, Wet, -V2"Ashes, Coal, Wet, -3"Ashes, Fly (See Fly Ash)Asphalt, Crushed, -V2BagasseBakelite, FineBaking PowderBaking Soda (Sodium Bicarbonate)Barite (Barium Sulfate), + V2 -3"Barite, PowderBarium CarbonateBark, Wood, RefuseBarley, Fine, GroundBarley, MaltedBarley, MealBarley, WholeBasaltBauxite, Crushed, -3"Bauxite, Dry, GroundBeans, Castor, MealBeans, Castor, Whole ShelledBeans, Navy, DryBeans, Navy, SteepedBentonite, CrudeBentonite, -100 MeshBenzene HexachlorideBicarbonate of Soda (Baking Soda)Blood, Dried 35-45[~;I~~~ ~~~~~~~~]9-1 B-1B-2B-1B--3B-1B-.3B.1B-1B-1B-2B-1B-1B-1 B-1B-1 B-1B-1B-1B-1B-1 B--1C..-1C,1C,1C.1C1C1C2C1C1C1C1C1C1C1C1C1C1C1060-8060-7545-4855-6149-6140-6045-5043-5037-4530-453530-3520-222025-322535-4520-301925-3523-3535-4530-5085-120120-150100-15075-9540-4525-302240-455-1512-1540-501712-15562140-4532-4025454530-3540-4540-4522-4018-2520-251225-3035-404035-4040-5075-9090-11080-120A35P03566565666655665566568886777666666655666666556665666666667781.51.8B25NB35TYC25035LNXY035QVC45T035TC25QC25A45XYE45B25MYC25PQA35PA45XC25PQA35PUYC37037037045TVC36U036036C35SB45HW035HWE35HWB35HWB35JNYC35JYB25PC25YE35E35B35PYB35PB35P045HWC25PQC25B35PUC45HW045HWC25XC45XYC35HWYB35YB45HWB45HWB35HWC45HW045HWA36L036C37.41.01.0.91.0.91.0.5.5.91.51.0.5.6.6.4.41.21.21.31.03.04.04.01.0.7.81.0.7.5.5.7.6.4.5.5.6.4.41.01.01.0.6.9.8.9.5.5.6.61.32.02.12.0Clay, Ceramic, Dry, FinesClay, Dry, LumpyClinker, Cement (See Cement Clinker)Clover SeedCoal, Anthracite (River & Culm)Coal, Anthracite, Sized, -1/2"Coal, Bituminous, MinedCoal, Bituminous, Mined, SizedCoal, Bituminous, Mined, SlackCoal, LigniteCocoa BeansCocoa, NibsCocoa, PowderedCocoanut, ShreddedCaffee, ChaffCoffee, Green BeanCoffee, Ground, DryCoffee, Ground, WetCaffee, Roasted BeanCoffee, SolubleCoke, BreezeCoke, LooseCoke, Petrol, CalcinedCompostConcrete, Pre-Mix DryCopper OreCopper Ore, CrushedCopper Sulphate (Bluestone)Copperas (See Ferrous Sulphate)Copra, Cake, GroundCopra, Cake, LumpyCopra", LumpyCopra, MealCork, Fine GroundCork, GranulatedCorn, CrackedCorn Cabs, GroundCorn Cabs, Whole *Corn Ear *Corn GermCorn GritsCornmealICorn Oil, Cake.Corn SeedCorn ShelledCorn SugarCottonseed, Cake, CrushedCottonseed, Cake, LumpyCottonseed, Dry, DelintedCottonseed, Dry, Not DelintedCottonseed, FlakesCottonseed, HullsCottonseed, Meal, ExpellerCottonseed, Meal, ExtractedCottonseed, Meats, DryCottonseed, Meats, RolledCracklings, CrushedCryolite, DustCryolite, LumpyCullet, Fine1 A-1 8-1 C2D1A-18-1C2A-282A-281A-181 A-1 82A-282D1 A-1 82D18281 A-1 81 A-1 81 A-1 81 A-1 818183D3D3D3A-383D3D3D2A-28-2C1 A-1 8-1 C2A-28-2C2A-28-2C2D1 A-1 8-1 C1 A-1 8-1 C1A-18-1C1A-18-1C2A-282A-281 A-1 8-1 C1A-1 8-1 C1 A-1 81A-181 A-1 8-1 C1 A-1 8-1 C181 A-1 82A-281A-181A-181 A-1 81A-183A-381A-181 A-1 81A-182A-28-2C2D2D3Dr@~1con tinantaiJ11Cui let, LumpCulm, (See Coal, Anthracite)Cupric Sulphate (Copper Sulfate)Detergent (See Soap Detergent)Diatomaceous ~arthDicalcium PhosphateDisodium PhosphateDistiller's Grain, Spent, DryDistiller's Grain, Spent, WetDolomite, CrushedDolomite, LumpyEarth, Loam, Dry, LooseEbonite, CrushedEgg PowderEpsom Salts (Magnesium Sulfate)Feldspar, GroundFeldspar, LumpsFeldspar, PowderFeldspar, ScreeningsFerrous Sulfide, -V2"Ferrous Sulfide, -1 00 MeshFerrous SulphateFish MealFish ScrapFlaxseedFlaxseed Cake (Linseed Cake)Flaxseed Meal (Linseed Meal)Flour, WheatFlue Dust, Basic Oxygen FurnaceFlue Dust, Blast FurnaceFlue Dust, Boiler, DryFluorspar, Fine (Calcium Fluoride)Fluorspar, LumpsFlyashFoundry Sand, Dry (See Sand)Fuller's Earth, CalcinedFuller's Earth, Dry, RawFuller's Earth, Oily, SpentGelatine, GranulatedGelena (See Lead Sulfide)GilsoniteGlass, BatchGlue, GroundGlue, PearlGlue. Veg. PowderedGluten, MealGranite, FineGrape, PomaceGraphite FlakeGraphite FlourGraphite OreGuano Dry *Gypsum, CalcinedGypsum, Calcined, PowderedGypsum, Raw, -1"Hay, Chopped *Hexanedioic Acid (See Adipic Acid)Hominy, DryHops, Spent. DryHops, Spent, Wet1235-433-340-433-3140-120-752503500350C3500450037A37C36A36LMP66668877566666667666.4.4.6.42.02.21.61.0.52.02.02A-281818183D3D201A-1 8-1 C-I--40-456342-56327272240-260200-270180-23030-15030-180240-260302020C25025A35LMPA35PU 181A-18-1C1A-18-1C203D3D2020203D1 A-18-1 C201A-182A-282020201 A-18.6A35RA35RA35R835C36A35PA35LPA35RC47835U835LMA35LMC25HU835036A46MY1.41.41.01.41.41.21.21.7.6.8.62.02.02.01.6-2.012060-654032-4053-566885-9055-958666567766656668788767777665645-5020-3020-3036-4013-153370-85125-1401207080-958050-554017-2213-1513-155-627-3020-4532A35MR 1.0.5.5.4.41.01.52.02.02.42.01.61.51.51.0.91.0.4.9.5.6835C35825C35C45A35037A36C37837036E45E46816836A36835A45825A351A-1B-1C1A-1 B-1C1A-1 B-1 C1A-1B-1C1 A-1 B2A-2B30203030202A-2B202020201B1B1B1BIce, CrushedIce, CubesIce, Flaked *Ice, SheilIlmenite OreIron Ore ConcentrateIron Oxide, MillscaleIron Oxide PigmentIron Pyrites (See Ferrous Sulfide)Iron Sulphate (See Ferrous Sulfate)Iron Sulfide (See Ferrous Su'fide)Iron Vitriol (See Ferrous Sulfate)Kafir (Corn)Kaolin ClayKaolin Clay, TalcKryalith (See Cryolite)LactoseLamp Black (See Carbon Bla:ck)Lead ArsenateLead ArseniteLead CarbonateLeadOre,l/s"Lead Ore, Vi'Lead Oxide (Red Lead), -1 00 Me.shLead Oxide (Red Lead), -200 MeshLead Sulphide, -100 MeshLignite (See Coa,Ugnite)Limanite, Ore, BrownLime, Ground, UnslakedLime, HydratedLime, Hydrated, PulverizedLime, PebbleLimestone, AgriculturalLimestone, CrushedLimestone, DustLindane (See Benzene Hexabhloride)Linseed (See Flaxseed)Litharge (See Lead Oxide)LithoponeMaize (See Milo)Malt, Dry, GroundMalt, Dry, WholeMalt, MealMalt, SproutsMagnesium Chloride (Magnesite) .Manganese Dioxide *Manganese OreManganese OxideManganese SulfateMarble, CrushedMarl, (Clay)Meat, GroundMeat, Scrap (with bone)Mica, FlakesMica, GroundMica, PulverizedMilk, Dried, FlakeMilk, MaltedMilk, PowderedMilk Sugar135555160180NPNPPNRTHQTXHMYMPUYPXPMPX20-36120-12532-3640-45107501504545358-122619-26223519-245915835PUXE46T825815N826836E46T815N835A35P835NYC25MNC35845NYA35C35NYE45HKPWXE451B301A-1 B-1 C1 A-1 B-1 C2020301 A-1 B-1 C1 A-1 B-1 C201A-1B-1C1A-1B-1C1A-1B-1C1A-1 B-1C1 A-1 B-1C1 A-1 B-1 C2A-2B2A-2B675577756665666666.53.0.5.41.5.63.0.4.7.8.5.4.5.6.5.6.41.56050-806260-4515-3015-35-45-8-160B35QSC36T036TVE45E45C45K035QB35P036QC35QC15NQC36B25T67766666765751.01.6-2.02.1-2.51.51.5.6.6.6.7.4.5.61.41A-1B3D3D2A-2B2A-2B1 A-1 B2A-2B1B3D1B1A-1 B-1 C2D2A-2B-75-856090-10030.:354020-30,20-30707551120-1~0768042-484842-48120-13070-8080-902042-4545-4920-2130-778666688757776778866565-2.11.72.0.4.4.61.02.02.21.01.61.21.21.0.51.62.01.72.0.4.4.4.4.4036836837C45Q835PQE45KPQTA45KT837037836C25TUC16NT826NT846XA35MNP846C26A27C27835NY835PC25P835NYC15P2D2D3D1 A-1 81818283D3D2D3D3D3D2D1 A-1 83D3D3D3D1A-18-1C1A-18-1C1A-18-1C1 A-1 8-1 C1 A-1 B-1 CMilk, Whole, PowderedMillscale (Steel)Milo, GroundMilo Maize (Kafir)Molybdenite PowderMonosodium PhosphateMortar, Wet *Mustard SeedNaphthalene. FlakesNiacin (Nicotinic Acid)Oat HullsOatsOats, CrimpedOats, CrushedOats, FlourOats, RolledOleo Margarine (Margarine)Orange Peel, DryOxalic Acid Crystals -Ethane Diacid CrystalsOyster Shells, GroundOyster Shells, WholePaper Pulp (4% or less)Paper Pulp (6% to 15%)Parrafin Cake, -Vi'Peanuts, Clean, in shellPeanut MealPeanuts, Raw, Uncleaned (Unshelled)Peanuts, ShelledPeas, DriedPerlite, ExpandedPhosphate Acid, FertilizerPhosphate, Disodium(See Disodium Phosphate)Phosphate Rock, BrokenPhosphate Rock, PulverizedPhosphate SandPlaster of Paris (See Gypsum)Plumbago (See Graphite)Polyethylene, Resin PelletsPolystyrene BeadsPolyvinyl, Chloride PelletsPolyvinyl, Chloride PowderPotash (Muriate) DryPotash (Muriate) Mine RunPotassium CarbonatePotassium Chloride PelletsPotassium Nitrate, -Vi'Potassium Nitrate, -1/ a"Potassium SulfatePotato FlourPumice, -Vi'Pyrite, PelletsQuartz, -100 MeshQuartz, V2Rice, BranRice, GritsRice, HulledRice, HullsRice, Polished14.6062'2020,4550'232-65-50-23-42-15-3335-4232-505045C35NC45Q045C45815N835Y835N835835C35026835815N837U836TU836TUC36TU836TU6666566666765.61.51.5.8.4.4.5.5.5.5.6.6.4-298565-8545-6070-80110-13090-11090-10090-10010411510-136527-4185-90318045130-18060-6580-9082-8540-5045-5515-3515-2515-505-1520-2540-5055-6520-3572877778888886777678.62.11.71.()1.72.81.72.02.62.02.3.71.0.62.0.61.52.02.42.22.01.6.8.8.6.6.8.6.92.01.0.81.0847837827D37Z827A27845UX836826C36835PA46D37HKQUD37YC37C36836E47TW8468835QC35Q835FQ835QXY825XA45XY836A36Y8368877776666567771A-1 B-1 C1A-1B-1C2A-2B-2C1A-1 B-1 C1A-1 B-1 C1A-1B-1C1 A-1 B-1 C1A-1 B-1 C1 A-1 B2A-2B2D1 A-1 B-1 C1A-1B-1C3D3D3D3D3D3D3D3D3D3D3D1A-1B-1C2D2D2D1B2D3D3D3D2D2D3D2D1 A-1 B-1 C1 A-1 B-1 C1 A-1 B-1 C1A-1B-1C1 A-1 B-1 C1 A-1 B-1 C2D2D2D-A36-20-71-1.075Rice, RoughRosin, -Vi'Rubber, PelletedRubber, Reclaimed, GroundRyeRye BranRye FeedRye MealRye MiddlingsRye, ShortsSafflower, CakeSafflower, MealSafflower SeedSaffron (See Safflower)Sal Ammoniac (Ammonium ()q)(),~36Shaft Mounted Reducers~~~fEssentially very similar to thescrew conveyor drive, this type ofunit requires the use of a thrust bea-ring, drive shaft and seal assembly.As with the screw conveyor drive, itis possible to combine the motormount integrally with the reducerunit, and power is transmittedthrough a V-beltdrive. Such a unit isusually used where special sealingarrangements are required on theconveyor shafts, such as a packedgland seal, or where very high hor-sepower must be transmitted whichis not within the parameters of thescrew conveyor drive.I()C>I Jr~--~()/;-'/~rGearmotor DrivesIntergral gearmotor drives can beused to power conveyors througheither a direct, low speed couplingmounted to the conveyor drive shaft(see illustration) or ttlrough a rollerchain drive. The former is traditionallymounted on a scoop base attached tothe trough end while the latter ismounted directly to the top of theconveyor or on a adaptor base orbase plate beside the conveyor.These units are used in instanceswhere high horsepower is being trans-mitted or when a variable speedgearmotor is used to vary the feedrates of a metering screw.~"'""Q--~~/1~I~~1~~'/./'~l~~~~~~~~~~~~37Other Drives and ConfigurationsNumerous other methods of driving a screw conveyor are availableamong which are variable speed D.C. motors with SCR rectifiers,hydraulic drives or variable pitch sheaves between motor and reducer.Also, when inertia loads are encountered when starting heavily loadedconveyors or when high horsepowers are used on large or longconveyors, fluid couplings should be incorporated in the drivearrangement. We suggest you contact our Engineering Department forspecific suggestions and recommendations regarding such matters.SPECIAL FABRICATION MATERIALSScrew conveyors are normally fabricated of low carbon, hot rolledsteel plate with the exception of the drive, end and coupling shafts whichare of cold rolled bar stock. Certain materials and conditions howeverrequire the use of materials other than mild steel. These materials andtheir advantages are discussed in further depth in the followingparagraphs. Further information and assistance can be obtained fromour Engineering Department for your particular applications.Hard Surfaced Conveyor ScrewsConveyor screws that will be in contact with highly abrasivematerials are often hard surfaced using fusible alloy hard surfacingmaterials or hard facing electrodes. These materials are applied to theflight surface in a width proportional to the conveyor's cross sectionalload. These dimensions are given in Table 13. The dimensions givenpertain to standard application however for extremely abrasiveconditions or higher than normal trough loadings, it may be advisable toharden the full flight face, periphery and even the pipe.l.+f1HELICOID SECTIONALTABLE 1369101214161820241"11/2"11/2'2"2"21/2'21/2'3"3"38Abrasion Resistant SteelIf necessary, conveyor screws and components can be suppliedfabricated of abrasion resistant metals with a surface hardness of up to360 Brinell. This can substantially increase the life of componentssuch as conveyor screws and troughs which are subjected to the greatestwear and therefore substantially increase their useful life.Stainless Steel and Other AlloysMany requirements call for the use of materials other than mild steelto be in contact with the conveyed material due to uncommon variablessuch as corrosion, contamination or elevated temperature. To suit theseconditions fabrication materials such as stainless steel, Monel, Inconeland aluminum alloys may be used to suit the applications.Coating and PlatingConveyor screws and components may also be plated or dipped tosuit numerous requirements and conditions. Hot dip galvanizing, nickleor chrome plating and rubber or Teflon coating are often encountered.High Torque Drive ComponentsCertain applications may arise where the normal horsepower rangeof standard screw conveyor components will be exceeded. For casessuch as these high capacity coupling bolts, shafts and pipes areavailable.[~;~~~~ ~~~~~~~390-- Helicoid DesignationThe letter 'H' indicates screw conveyor with helicoid flighting. The figuresto the left of the letter indicate the nominal outside diameter of the conveyor ininches. The first figure following the letter is twice the diameter of the cou-plings in inches. The last two figures indicate the nominal thickness of flightingat the outer edge in 1/64". Thus 12H408 indicates a 12" diameter helicoidconveyor for 2" couplings with flighting 8/64" or 1/8" thickness at outer edge.Due to the nature of the forming process, the periphery of a helicoid flight isapproximately 1/2 the thickness of the material at the root where it is welded tothe pipe. Because most wear is concentrated on the periphery, helicoid flightsare less suitable for handling abrasive materials than sectional flights.Sectional Designation:The letter'S' indicates screw conveyor with sectional butt welded flighting.The figures to the left of the letter indicate the nominal outside diameter of theconveyor in inches. The first figure following the letter is twice the diameter ofthe couplings in inches. The last two figures indicate the nominal thickness offlighting in 1/,64/'. Thus 12S612 indicates a 12// diameter sectional conveyor for3" couplings with flighting 12/64" or 3/16'/ nominal thickness.Sectional flights, due to the nature of the forming process, maintain a uniformthickness between the root and the periphery. They are thus more suitable forabrasive applications due to the greater thickness of material at the pointsubjected to the greatest wear.1:\\Numerical Designation System for Standard Conveyor ScrewsConveyor screws are supplied with right hand flighting unless ortherwise specified.Conveyor screws are supplied in standard lengths as shown on pages 42 through 46 unlessortherwise specified.Flighting will cover the entire length of the conveyor pipe unless otherwise specified.Conveyor screws are fabricated of carbon steel unless otherwise specified. For informationregarding materials in which conveyor screws may be obtained, see Special FabricationMaterials, page 38.40CONVEYOR SCREWSHelicoid Conveyor Screws:Helicoid flighting is formed by cold rolling special analysis strip into a continuoushelix that produces a work hardened, smoothly finished flight surface. The flighting isthen fastened to the pipe by intermittent welds with steel end lugs at each extremity toreinforce the tips. They may also be continuously welded on either one or both sides ifso required. The pipe has seamless internal collars inserted and plug welded in bothends to accept the shafts. Both helicoid and sectional flighting of the same diameter andshaft size are interchangeable.Sectional Conveyor Screws:Sectional flights are blanked from a steel plate, formed into a helix and then buttwelded together to form a continuous helix on the pipe. The flights are normally fastenedto the pipe by intermittent welds however can be continuously welded on one or bothsides if required. The pipe has seamless internal collars inserted and plug welded in bothends to accept the shafts. Sectional flight conveyor screws can be supplied in specialdiameters, pitches, thicknesses, pipe sizes and shaft diameters as well as in a variety ofmaterials such as stainless steel, Inconel, Monel, copper, brass and other metals.Sectional Flights:Sectional flights are formed from steel plate with a lead slightly longer than theirpitch. This assures a tight grip when mounting them on the pipe. They are available in allstandard sizes and can also be supplied in special diameters, pitches, thicknesses andpipe sizes.Ribbon Flights:Ribbon flights are commonly used to handle sticky or gummy materials whichnormally build up at the pipe of flight junction point. Their open design minimizes thisproblem. They are also used for mixing dry materials in transit as long as the crosssectional load is greater than the face of the flight. The pipe has seamless internal col-lars inserted and plug welded in both ends to accept the shafts. Ribbon flight can besupplied in special diameters. pitches, thicknesses, pipe sizes and shaft diameters aswell as in a variety of materials such as stainless steel, Inconel and Monel.Paddle Conveyor Screws:Paddle conveyor screws are commonly used to mix material in transit when con-veying efficiency is not important. The paddles are bolted through the pipe and areinfinitely adjustable. The pipe has seamless internal collars inserted and plug welded inboth ends to accept the shafts. Paddle screws can be supplied in special diameters,pitches, thicknesses, pipe sizes and shaft diameters as well as in a variety of materialssuch as stainless steel, Inconel and Monel.Cut and Cut & Folded Flights:Notches cut in the periphery of a conveyor screw creates a very effective mixingaction with most materials, particularly at high speeds. By folding over the cut, a moreviolent mixing action is achieved since the material is spilled over itself. The cut flight isalso useful for moving materials which tend to pack while cut and folded flights areuseful in cooling, heating or aerating light substances.Internal Collars, Coupling Bolts and Quick Release Keys:Internal collars are used in all types of conveyor screws to create a close fit be-tween the inside diameter of the pipe and the outside diameter of the shaft. Whenpurchased separately they are not drilled for the coupling bolts as the pipe ends arealways drilled after assembly.Coupling bolts are machined from analysis steel with the thread cut to the properlength so as only the bolt shank is in contact with the coupling shaft and pipe, therebyensuring full torque capacity and minimum wear. Special self-locking nuts are providedto prevent the nut from working loose during operation which can lead to damage anddowntime.Quick release keys allow for the removal of an intermediate section of conveyorwithout dismantling the entire screw conveyor. To remove a section, the intermediatebolts are removed, the key is removed and the entire section simply lifts out while theshafts remains in position in the trough.1@::lcontinantal,1411