Spotlight on GravimetricBlending and Control Systems

Pellets, Powders, Regrind....

If you can extrude or mold it,

we can blend it.

PROCESS CONTROL CORPORATIONAuxiliary Equipment for the Plastics Processing Industry

PPrecise BBlends oof TTwoto EEight IIngredients bby WWeightX Series continuous gravimetric blenders aredesigned to produce precise, homogenousblends by weight, regardless of ingredientbulk density variations. The X Series controlsystem incorporates the latest in micro-processor technology for total automation ofrecipe entry and storage, inventory controland process monitoring. All hardware andsoftware has been developed in-house byProcess Control with an emphasis on relia-bility and ease-of-use. Functions are menu-driven and step the operator through therequired sequences of actions with simpleinstructions.

Superior LLow RRateMetering AAccuracyFor metering ingredients at low rates, the XSeries blender offers unsurpassed weighingresolution and unique feeder designs to guar-antee accurate and consistent feeding. TheProcess Control weighing system uses 20-bitA/D resolution which enables us to detectweight changes of one part per million. Thepatent-pending Tube Hopper has beenshown to improve low-rate feed accuracy byas much as 40% over conventional feederdesigns. We have wide experience with avariety of materials and applications andstand ready to assist you with your ownrequirements.

Benefits oof GGravimetricBlending SSystems• Improved product quality and consistecy• Minimize use of expensive ingredients

for reduced manufacturing cost• Reduce inventory of blended material• Allow faster startups and product

changeovers “on-the-fly”• Provide inventory and production reports

for management• Reduce labor costs through automatic

operation• Reduce scrap or off-spec product• Communicate with other systems for

complete plant level control

Continuous Gravimetric Blender

Integral Loader Support Platform

supports typical loading equipment

without external support.

Steep Wall Hoppers Promote Flow

Materials which do not flow

well, such as regrinds and

flake, can create problems.

With standard feeder

designs, these materials

feed inconsistently and can

even “bridge” causing all

feeding to stop.

To solve these problems,

Process Control utilizes

steep wall hoppers with

enlarged feed openings

when necessary to promote

consistent material flow.

Clear Polycarbonate

Access Doors

allow visual

inspection/cleanout

of hopper contents.

Low-Rate Tube

Hopper

precisely meters

critical additives

at low rates.

Onboard Drive Electronics

use PWM drive system to

precisely control feeder speed

and reduce field wiring.

Large Polycarbonate

Cascade Chamber Door

for easy cleanout.

Precision Ingredient

Hopper Load Cells

accurately measure material

weight loss under real-world

conditions.

Quick-Change

Auger/Metering Units

use variable speed

DC gear motors

with closed-loop

control for precise

ingredient measuring.

Integral Downcomer

maintains supply of blended material for

use by process. Plug-flow design avoids

de-mixing of ingredients.

Onboard Weighing

System digitizes load

cell signals for error free

transmission to central

computer. System designed

to detect changes of 1 part

per million.

Material Cleanout Drains

with manual valves for quick

material cleanout and

changeover.

Cascade Mixing Chamber

thoroughly homogenizes blend

with no moving parts.

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The XU Series continuous gravimetric powderblender offers unsurpassed blend accuracy andblend homogeneity in a wide range of configu-rations to meet the needs of any application byincorporating the PF Series powder feeders. Itallows gravimetric blending of non-freeflowingpowder materials with freeflowing powder andpellet materials at unprecedented metering andmixing accuracy.

The powder feeders allow rates as low as 0.2PPH and as high as 3,000 PPH. Metering augersare available in full pitch or 1/2 pitch configura-tions with helix diameters from 1/4 inch to 2-1/4 inches. The drive system of all blender com-ponents utilizes a PWM drive with a DC gear-motor and encoder for accurate motor speedfeedback. This allows each of the individualfeeders to maintain a constant weight through-put. The weighing system is designed with DSP(digital signal processing) technology (patentpending) to filter out unwanted noise and vibra-tion which can wreak havoc with any feedingsystem, especially at very low feed rates.

Incorporated into the electro-polished stainlesssteel design is a patented round-to-trough feed-ing area which provides more consistent massflow for better metering accuracy. The feeder isdesigned with a steep wall, removable hopperwhich features a dust-tight band clamp for easymounting of hopper extensions and quick disas-sembly for clean out. The bottom trough designis optimized to provide maximum materialexposure to the auger.

The XU Series Continuous Powder Blender isalso available in food grade stainless steel.

The operator enters the desired blend recipe atthe operator station. All ingredients are simul-taneously metered in the correct blend ratios byaugers from individual weighed PF Series pow-der feeders. The ingredients then flow througha cascade chamber which produces the bestblend homogeneity.

Continuous Gravimetric Powder Blender

Universal FrameThe universal frame isavailable in 4 and 6 element configurations.

Stainless Steel WeighHopperThe stainless steel weigh hop-pers are electro-polished andavailable in food grade.

Gear MotorThe gear motor utlizes aPWM drive and encoderfor high accuracy.

Metering AugersAugers are availablein a full pitch or 1/2pitch and up to 2 1/4inch diameter.

Weighing PlatformDual load cells areincorporated into theplatform which is heldby quick clamps .

Cascade ChamberThe cascade chamber isfor mixing all of the ingre-dients.

Feeding AreaThe feeding areais round-to-troughand agitated.

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Material Supply HopperOptional supply hopperswith knife gates are avail-able.

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EExtruder TThroat MMounting

When space is available, the blender with integral down-comer may be bolted directly to the throat. This is the sim-plest installation and provides excellent blend homogeneityand easy cleanout.

Mezzanine MMounting

For applications with an existing mezzanine structureabove, this arrangement offers the benefits of throatmounting. This blender configuration uses a remote down-comer mounted on the extruder throat to capture the grav-ity-fed blend of materials from the mezzanine-mountedblender.

Off-Line MMounting wwith PPressure CConveying

For applications where the blender must be mounted off-line, the pressure conveying system offers the benefits ofextruder throat mounting. As the blend is produced, it isconveyed via pressure continuously to the extruder throat-mounted remote downcomer. This prevents demixing andallows accurate calculation of extruder rate for gravimetricextrusion control applications.

Off-Line MMounting wwith VVacuum CConveying

For applications where there is not enough headroom foreither throat or mezzanine mounting, or were more thanone extruder is to be served by the same blender, off-linemounting is to be used. The blender is mounted on a standwith a vacuum pickup box below it to capture the materialblend. On demand, the blend will be vacuum-conveyed tothe machine(s) being served. Care must be taken to mini-mize the chances for blend separation during this convey-ing.

Extruder Throat Mounting

Mezzanine Mounting

Off-Line Mounting with Pressure Conveying

Off-Line Mounting withVacuum Conveying

Simple InstallationThe X Series has been designed to makeinstallation quick and easy, based on ourexperience with thousands of continuousgravimetric blender projects throughout theworld.

Mechanically, the blender has been designedto mount directly to the throat of the extrud-er, on a mezzanine or on a blender stand. Anintegral loading support platform is includedwhich allows most typical vacuum receiversand/or shutoff valves to be mounted withoutadditional support.

Electrically, field wiring has been kept to anabsolute minimum due to our unique distrib-uted control system. All drive system andweigh system connections are factory wired.The operator station, which houses the cen-tral computer, may be located up to 1000 feetfrom the blender. Wiring between theblender and the operator station consists of afour-wire network and power connections.When standard Process Control vacuumreceivers are used, they are designed to plugright in to the blender.

Superior Blend HomogeneityThe quality of your end product is influencedby many factors, including consistency of theblend being fed to your process. Each ingre-dient in your blend has a purpose and the bestresults are achieved when the blend ratios arehighly consistent in the short term.Continuous blenders achieve superior blendhomogeneity by precisely metering eachingredient simultaneously in the correctratio. The individual material streams arebrought together in a cascade mixer designedto thoroughly homogenize the blend. Theresultant blend is then captured and pre-served all the way to the process. This con-tinuous approach produces more homoge-nous blends than designs which rely onmechanical agitation for mixing.

Continuous Blender Features

Mixing Chamber

• Agitator designed for

waterfall type mixing

to ensure every

batch is mixed

• Engineered for no dead spots and to achieve

a consistent homogenous blend

• The proximity switch controls the mixer outlet gate

to prevent classification of mixture

Integral Loader Support Platform

Supports vacuum receivers without

the need for external support

Pneumatic

Metering Gate

Pulsing v-gate to

achieve dosing accuracy of every

ingredient in each and every batch

Touchscreen

Microprocessor

• Color touchscreen

operator interface

that insures ease of use and quick startups

• Standard ethernet

port for communication

ability and integration

with remote systems

• Ability to show in real time the actual

throughput and the maximum throughput

based on the current recipie running

• Ability to show in real time the target dis-

pense and the actual dispense achieved

• Ability to perform automatic calibration

when a new recipe is entered

• Can be remote mounted

• Ability to perform a test dispense for

metering accuracy verification

Segmented Material

Hopper

• Blenders have

four to eight ele-

ments in individual

fixed hoppers that are

welded together

• Special configurations for

up to 12 ingredients

Clean-

out

Dump

Chute

Fixed inside the

blender behind the

weigh pan for ease of

material change

Air Hose

The attached air hose

and nozzle ease the

cleaning process

Weigh Hopper

• Rests on dual load

cell platform

• Includes integral batch dump valve

• Easily removeable with no tools for cleaning

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The Guardian® Series gravimetric batch blenderwas developed for processors who want the sim-plicity of operation combined with the mostaccurate dispensing and superior blend homo-geneity at a low cost.

The outlet of each of the individual materialhoppers is equipped with a fast acting V-gatevalve. Each of the materials is dispensed sequen-tially into a common weighing hopper in thedesired proportions. The weighed materials arethen released into a separate mixing chamberwhich provides the most consistent homoge-neous blend of any batch type blender.

Process Control engineers have produced a high-ly advanced metering and weighing system thataccurately controls each ingredient of everybatch to the desired amounts and is not averagedover multiple batches as is common in otherbatch blenders in the industry. At the blender’shighest accuracy setting, each ingredient can bedispensed to an accuracy of +/-0.02%.

The metering gates are controlled with one ini-tial dispense cycle and then the balance of therequested weight amount is fine tuned by "shortcycling" the gate. Every batch is exact, batchafter batch. The competition makes up for dis-crepancies on the next batch. Why assume thattheir next batch will correct the previous inaccu-rate batch? Do it right the first time, every time.

In addition to precise batch-to-batch dispensing,the performance of the mixer is just as critical tothe end product. The mixer actually determineshow uniform the blend will be. Process Controlhas spent many years of research and testing indeveloping the most thorough homogeneousmixer in the industry. Inadequate mixing canlead to inconsistent product characteristics suchas color variations or other imperfections.

The mixer section of a Guardian blender isdesigned with total mixing action and NO deadspots. No other blender design comes close tothis. No stratification, no matter how dissimilarthe blended materials are in specific gravity orhow they may vary in composition.

The Guardian® Series blenders have incorporat-ed in the design a built in clean-out system. Witha pull-out drain chute and manual slide-gatecontrols, the blender can be cleaned-out quicklyand easily during product change-overs.

Guardian® Gravimetric Batch Blender

CControl EExtruderOutput bby WWeight

For processors who seek the benefits of bothgravimetric blending and control of extrud-er output by weight, we offer a solution thatcombines both technologies in one integrat-ed, easy-to-use system. In many applica-tions, line speed control is also added forcomplete control of product weight perlength. This feature can be retrofitted tomost existing blenders in the field for bothmono- and coextrusion applications.

Benefits oof GravimetricExtrusion CControl

• Improved Product Quality• Reduced Material Usage• Quicker Startups & Product

Changeovers• Reduced Scrap• Improved Product Repeatability• Accurate Inventory Reporting• Improved Identification of

Off-Spec Product

Part oof aa CCompleteGravitrol® Coextrusion Control SSystem

For coex applications, the PCC Blender ispart of a complete Gravitrol® system forcontrolling product layer ratios and totalline throughput. On a typical coex line, lay-ers which require blending use X Seriesblenders and single-component layers useHG Weigh Hoppers. Both the blenders andweigh hoppers report actual extruder usageback to the central Gravitrol® computer.This information is periodically compared tothe desired layer percentages and adjust-ments are made to the extruder screwspeeds. In addition, line speed can beadjusted for complete control over productweight per length.

Gravitrol® Gravimetric Extrusion Control Systems

Blender OOperation wwithGravimetric EExtrusion CControl

The operator presses RECIPE and enters the desired blendpercentages by weight and the desired extruder rate into theoperator station. When RUN is pressed the blender auto-matically maintains the desired blend percentages by weight.Simultaneously, the blender computer calculates the actualextruder usage rate and periodically adjusts the extruderscrew speed to maintain extruder output to +/-0.5% byweight.

In applications which incorporate line speed control, theoperator also enters desired weight per length as part of therecipe and the computer controls line speed in addition toextruder speed to maintain the desired product weight perlength.

Touchscreen Operator Interface Standard on GuardianIn order to produce a desired blend of materials theoperator presses RECIPE and enters the recipe, whichconsists of the percentage by weight for each ingredient.The recipe may be keyed in directly or recalled from upto 400 stored recipes.

The operator then presses the AUTO button to startblending. Once the blending has started, the computercontinuously monitors the blender operation and cor-rects the individual feeder speeds to maintain thedesired blend ratios.

Operation SStation HHighlights:

• Color touchscreen operator interface that

insures ease of use and quick startups

• Standard ethernet port for communication

ability and integration with remote systems

• Ability to show in real time the actual

throughput and the maximum throughput

based on the current recipie running

• Ability to show in real time the target dis-

pense and the actual dispense achieved

• Ability to perform automatic calibration

when a new recipe is entered

• Can be remote mounted

• Ability to perform a test dispense for

metering accuracy verification

Total Process Computerization

BBlend HHomogeneity iis KKey to PProduct QQualityBlend accuracy is a term commonly used by blendermanufacturers to rate the performance of their sys-tems. Accuracy is an important specification, butit is often stated over a long time period which haslittle relationship to the consistency of the processor end product. Blend homogeneity, which is justshort-term blend accuracy, is much more impor-tant to your product quality. For example, the twoboxes at right are each filled with 80% base mate-rial and 20% additive. Even if the blend containedin each box is accurate to 0.10% there is a big dif-ference in the homogeneity. If these two boxeswere fed to side-by-side extruders, significant dif-ferences in the end products would be seen. Themore homogeneous blend will produce the superi-or product and allow you to adjust your recipe forlowest material cost.

Batch BBlenders RRely oon Mechanical AAgitationBatch blenders use mechanical mixers to transformthe layered materials into a usable blend. There aremany different mixer designs and some do a betterjob than others of homogenizing the materials. Theresulting blend consistency is highly dependent onmany factors – the mixer design, the blend ratios, theshapes and densities of the materials, and mix time.When mixed, smaller, denser materials tend to settletowards the bottom through the larger, lighter mate-rials. For less critical applications or applicationswhich run the same blend recipe and materials day-to-day, batch blenders can be a cost-effective alter-native.

Continuous BBlenders OOfferImproved CConsistencyWith a continuous blender, each component is simul-taneously metered by weight in the desired blendratios. The individual material streams are combinedin a cascade mixing section, which homogenizes theblend and directs it to the process. Below the cascademixer, the resultant blend is typically stored in a plug-flow hopper which preserves the blend consistency allthe way to the process. At no time is mechanical agi-tation relied on, so superior blend homogeneity isachieved across a wide range of materials and ratios.

Comparing Continuous and Batch Blending

Continuous BBlender OOperation

Materials are kept in separate weigh hoppers,each mounted on a load cell which measures theweight of the hopper and its contents. Target meteringrates are determined for each material based on therecipe and the current blender total rate. Asthe mate-rials are simultaneously metered by auger into thecascade mixing chamber, the actual metering rateof each ingredient is frequently calculated from theweight loss of the hoppers. These actual rates are com-pared to the target rates and the speeds of the augers areadjusted to correct for any variation, maintaining anaccurate blend. The materials simultaneously flowthrough the cascade chamber, thoroughly homogenizingthe blend. The resultant blend is then captured in aplug-flow hopper designed to preserve the blend allthe way to the extruder throat (or other process).

Batch BBlender OOperation

Materials are kept in separate material hoppers above a central batch weigh hopper. c c T h emetering gates are controlled with one initial dis-pense cycle and then the balance of the request-ed weight amount is fine tuned by "short cycling" thegate. At this point, the materials are dropped into amixer which agitates the material for a fixed timeperiod, homogenizing the blend. At the end of themix cycle, the blend is available for the process.

Homogenous

Non-Homogenous

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Complementary Systems for Gravimetric Blenders

CContinuous GGravimetric BBlendersRequire PProper SSizing oofLoading SSystemWith a continuous blender, it is very important thatmaterial be delivered in a timely manner to theingredient hoppers. Process Control takes theguesswork out of this selection by providing a com-plete guaranteed system based on your usage andconveying distances. Our sophisticated computermodels and experience with a wide array of real-world applications assures you of a vacuum convey-ing system that meets your requirements.

Blender LLoading iis FFullyAutomatedThe blender ingredient hoppers call for material asrequired and a control system directs the operationof the pump and vacuum receivers to ensure thatmaterials are loaded to the proper stations at theproper times. Standard PCC receivers utilize prox-imity switches mounted in a location that willdeliver the optimum refill size. The receivers filluntil the specified volume is reached, eliminatingthe need for setting fill times. Loading by vol-ume is more precise than loading by time andmaximizes the output of the loading system.

Continuous GGravimetricBlenders AAlert OOperators TToLoading PProblemsWhen a loading system problem occurs, earlywarning can avoid costly line shutdown. Withthe X Series Blenders, the first notification of aproblem is typically a “SMALL REFILL” alarmwhich tells the operator that for some reason thelast refill was smaller than normal. Then, if theproblem is not corrected before the next refill, theoperator will get a “RUNNING OUT OF MATE-RIAL” alarm. If the problem is not resolved, thethird and final notification will be a “HOPPEREMPTY” alarm. In this case, the blender can beprogrammed to either shutdown until the problemis corrected or to remove the empty hopper fromthe recipe and make an off-spec blend in order tokeep the line running.

Vacuum RReceiversProcess Control Vacuum Receivers come ina range of sizes and designs for handlingpellets, regrinds or granular materials. Ourvacuum receivers are designed to bemounted at any point where resin deliveryis needed.

VacuumPower UUnitsOur Vacuum Power Units offerdependable and economical perform-ance for a wide variety of conveyingrates, distances and materials. Typicalapplications include in-plant distribu-tion systems and machine/blenderloading.

Each system is carefully sized using Process Control’s computersimulation to meet your conveying specifications.

Inventory MManagerThe Gravimetric InventoryManagement System will accu-rately weigh re-pelletized materialsprior to being re-processed orstored as inventory. The systemcan also be used to verify deliveredresins before entering them intoinventory. The GravimetricInventory Management Systemcan provide totals for a given pro-duction shift, a complete produc-tion run or an overall runningtotal

of material. It runs automatically with little or no operatorintervention logging shift weight totals.

AccuDispenseAccuDispense…an economical, single dose,gravimetric dispensing system.AccuDispense is a v ersatile product thatcan be used in not only the plastics industry,but also for pharmaceutical, chemical, andfood applications. With precision metering,this system delivers a pre-selected weight offree flowing material, such as powdered,flaked, granular and pelletized ingredients,directly to the process. AccuDispense isused when it is necessary to obtain pre-weighed doses of materialthat do not need to be blended, but require an accurate dispense.

Remote MManagerRemote Manager is acontrol/monitoring unitthat can be used toremotely communicatewith the X-Series line ofcontinuous gravimetricblenders, the GuardianSeries line of gravimetric batch blenders andthe Gravitrol extrusion and linespeed controlsystems. Management of processing machineryrequires continuous monitoring and control ofthe plant machinery to ensure process ltabilityand minimize downtimes. Remote Managerprovides powerful, realtime control and moni-toring of Process Control equipment to helpmeet these needs.

PCCWeb® WWeb BBasedEquipment CControl SSystemPCCWeb® is a system that enablesyou to monitor and control ProcessControl’s Guardian® series gravimet-ric batch blenders, X-Series continu-ous gravimetric blenders and/orGravitrol® extrusion and linespeedcontrol systems with a computerequipped with any standard webbrowser. Each of the Process Controlmini-op operator control panelscomes supplied with an embeddedweb server and a built-in Ethernet port. Using the Ethernet port, each of themini-ops can be connected into an internal network hub and then accessedby any computer within the network using a different address for each. Allof the screens have been pre-designed by Process Control software engi-neers and are used with any Internet web browser. There is no additionalwork required by users other than creating the link.

Director™Sequencing Control PPanelThe Director™ Sequencing Panel providesautomatic control for your complete vacu-um conveying system. The sequencingpanel controls the vacuum pump and vac-uum receivers to select which receiver isbeing loaded and the duration of the load.

Ethernet IIP/OOPC SServerThe EtherNet/IP OPC Server has been developed to assist inthe integration of Process Control blenders and Gravitrol sys-tems with customers PC based HMI and SCADA systems.The OPC Server allows anyOPC Client applications such asTrend Manager, MaterialManager, RSView, andMatrikon’s OPC Explorer tocommunicate with any ofProcess Control's blenders andGravitrol systems with anEthernet port.

Trend MManagerTrend Manager has been devel-oped to assist in tracking andplotting production data to bet-ter serve our customer's needs.Trend Manager can track theaccuracy of blend percentages,

layer distribution ratios, and overall line stability. By plotting andtracking information, the accuracy and consistency of blend per-centages can be easily and quickly verified. Additionally, totalmachine throughput data can be charted to verify overall line sta-bility on a mono-layer line and layer distributions on a co-extru-sion line to assure a good, consistent finished product.

Material MManagerMaterial Manager is adata collection tool thatanalyzes the materialusage of a blending sys-tem over time. It canaccurately track thematerial usage of eachcomponent on a blender used on a production line.Tracking material usage allows the system to report onhow much and which type of material was used on eachjob, shift, blender, and recipe. This system of recordingmaterial usage will provide processors with a betterunderstanding of the costs incurred in processing anorder.

Proper Loading is Key

...experience it at PCC!

Spotlight on Innovation

PROCESSCONTROLCORPORATION

WORLDHEADQUARTERS6875 Mimms DriveAtlanta, GA 30340USA

TEL 770.449.8810FAX 770.449.5445

PROCESSCONTROL GmbHIndustriestrasse 15D-63633 BirsteinGERMANY

TEL +49 0 60 54-91 29 0FAX +49 0 60 54-91 29 99

GUANGZHOUATLANTA PROCESSCONTROL EQUIPMENTCOMPANY, LIMITEDGuangZhouGuangDong ProvinceCHINA

TEL +86 20 62206502FAX +86 20 62206520

Innovations inscrap reclaim, blending,

feeding, turnkey materialhandling systems, and

gravimetric extrusion control...