final technical u. s. epa: bale coring technology projectinfohouse.p2ric.org/ref/13/12464.pdffinal...

Final Technical Reportto the US EPA:

Bale Coring Technology Project

NIST MEPEnvironmental Program

FINAL TECHNICAL REPORT TO THE US EPA:BALE CORING TECHNOLOGY PROJECT

Assistance ID Number: X825194-01-0

SUBMITTED TO:

Henry Ferland, EPA Project Officer

U.S. EPAU.S. EPA401 M Street SW, Mailcode: 5306W

Washington DC 20460

PREPARED BY:

Michelle Davis, CWC Project Officer

CWCCWCA division of the Pacific NorthWest Economic Region (PNWER)

2200 Alaskan Way, Suite 460Seattle, WA 98121

January 1999

This recycled paper is recyclable

DisclaimerCWC disclaims all warranties to this report, including mechanics, data contained within and all other aspects, whether expressed or implied,without limitation on warranties of merchantability, fitness for a particular purpose, functionality, data integrity, or accuracy of results. This reportwas designed for a wide range of commercial, industrial and institutional facilities and a range of complexity and levels of data input. Carefullyreview the results of this report prior to using them as the basis for decisions or investments.

REPORT NO. MX-98-1

ACKNOWLEDGMENTS

This project was fully funded by the US Environmental Protection Agency (EPA). CWC is a

nonprofit organization providing recycling market development services to both businesses and

governments, including tools and technologies to help manufacturers use recycled materials. CWC

is an affiliate of the national Manufacturing Extension Partnership (MEP) – a program of the US

Commerce Department’s National Institute of Standards and Technology. The MEP is a growing

nationwide network of extension services to help smaller US manufacturers improve their

performance and become more competitive. CWC also acknowledges support from the US

Environmental Protection Agency and other organizations.

The CWC acknowledges Re-Sourcing Associates, Inc. (Kent, Washington) for donating staff time

and facility space to devote to beta-testing of the coring equipment for plastic bales. The CWC

also acknowledges Jefferson Smurfit Recycling Co., (Renton, Washington) for donating staff time

and facility space to devote to beta-testing of the coring equipment for paper bales. Finally, the

CWC expresses sincere gratitude to Dynamark Engineering for design, manufacture, and testing

assistance with the coring equipment, including pro bono hours contributed to the project.

TABLE OF CONTENTS

Page

INTRODUCTION ..............................................................................................................1

PROJECT PLAN AND OBJECTIVES ............................................................................2

CONCEPT DEVELOPMENT...........................................................................................5

EQUIPMENT PROTOTYPE DEVELOPMENT & SAMPLING RESULTS ...............7

SAMPLING PROTOCOLS.............................................................................................19

RESULTS & RECOMMENDATIONS FOR APPLICATION

AND FINALIZING CORING TECHNOLOGY EVALUATION.................................23

REFERENCES..................................................................................................................31

TABLES

Table 1 Chronological Log of Equipment Design Changes and Sample ResultsTable 2 Film Sample Sorting Results (Excluding Fines Weight)Table 3 Chronological Log of Equipment Design Changes and Sample Results

(From Installation at Re-Sourcing Associates to End of Project)Table 4 Number of Samples per Bale for Various Confidence LevelsTable 5 Estimated Cycle Time for One Cored Sample

FIGURES

Figure 1 Saw TypesFigure 2 Sample Coring Pattern for Typical BaleFigure 3 Top-Down View of Coring Equipment

APPENDICES

Appendix 1 Survey (Query of Interest for Beta Test Sites for Bale Coring Technology)Appendix 2 Operating Instructions for Moisture Register ProductAppendix 3 Quality Data Logsheet for Plastic and Paper Bale Cored SamplesAppendix 4 Photos of First Version of EquipmentAppendix 5 Photos of Second Version EquipmentAppendix 6 Photos of SamplesAppendix 7 Example Graphs of Simulated Core Sample Data for OCC

INTRODUCTION

The proposed scope of this CWC project, with grant funding from the United States Environmental

Protection Agency (US EPA), in the amount of $120,000 USD, was to develop, manufacture, and

evaluate a core-sampling technique for cost-effective inspection of baled recycled materials,

including fiber grades, and rigid and film plastics. Core sampling allows extraction of one or

more cylindrical core samples from a bale of material so that a representative sample of the bale,

including material from the bale interior, can be inspected without breaking the bale apart.

Current methods to sample baled recycled paper and plastic for quality inspection involve a labor-

intensive breakdown of the bale for contaminant sorting, moisture detection, or other testing. Some

of the benefits of core sampling, in comparison to breaking a bale for quality control monitoring,

include:

• Bale breakdown is highly labor-intensive and therefore cost-prohibitive.

• The time to sort and weigh a cored sample is only estimated to be 2 to 10% of the time to sort

and weigh an entire bale (depending on type of baled material).

• Bale breakdown requires a large, clean surface area.

• Bale breakdown, especially for highly-compressed bales, introduces safety hazards.

• Bale breakdown requires clean-up and reincorporation of the material into the processing line.

• Analysis of the material is simpler.

• Foreign material stashed in the interior of the bale can be detected.

CWC collaborated with the US EPA, Pacific Testing Laboratories/Professional Service Industries

(PTL), and Dynamark Engineering, to develop the prototype core sampling equipment and evaluate

its performance in the field.

PROJECT PLAN AND OBJECTIVES

Initially, Pacific Testing Laboratories (PTL) was selected as the consultant to design and

manufacture the equipment. Both CWC and PTL parties conducted research on coring

technologies for other purposes -- the two existing coring technologies for baled material and the

survey results. We experimented with a number of different configurations and designs for the

cutting tools orbits, including off-the-shelf hole saws, a high-speed steel bit with scalloped edges,

and carbide-tipped bits for cutting into paper bales.

Figure 1 Saw Types

Connector Pin Connector Pin

Hole Saw Scalloped Bit Carbide-Tipped Bit

The initial objectives for the project were to:

• Design and manufacture the coring equipment;

• Obtain core samples from paper and plastic bales;

• Sort and evaluate those samples for contaminant and moisture levels;

• Correlate cored sample results (contamination levels) to actual full bale sorts, to statistically

compare contaminant levels in the bale vs. cored sample(s) from the same bale; and

• Compare the cost savings of core sampling as a quality control measure to the alternative of

breaking bales for inspection.

The project plan included beta testing at recycling facilities rather than at the higher end user for

the following reasons:

• No paper mills or plastic reprocessors are located proximately to CWC (who must be

involved in much of the troubleshooting, beta testing, and time/labor data).

• Recycling facilities, if they see beneficial opportunity to utilize core sampling, MAY be

interested in this technology given the equipment could eventually be fabricated at a reasonable

price, that is easily cost justifiable based on labor and time savings for quality control in their

facility.

The initial project plan was established as follows:

A. Develop Scope of Project

- Conduct survey of interest

- Complete literature and existing technology research

B. Design/Build or Buy Equipment

- Determine whether to buy or build based on cost, shipping, etc. If build locally:

- Develop equipment specs

- Solicit consultant for design and manufacture through competitive bid

- Manufacture

C. Determine Metric Protocols

- Develop methods to collect contamination and moisture data

- purchase certified scale to weigh sample components

- Develop systems to compile and graph quality and cost data

D. Test the Coring Equipment

- Identify facilities willing to test the equipment on their bales

- Install equipment

- Test by extracting and analyzing samples for contamination and moisture

- Purchase moisture analysis equipment (Oven or moisture meter)

E. Evaluate Productivity and Feasibility for Field Use

- Improved quality control

- Time saved on bale sorting

- Statistical comparison of cored samples vs. bale sorted samples

F. Publish Final Conclusions and Recommendations

Additional detail on various aspects of the project plan follows.

The CWC conducted a survey of recycling facilities and paper mills to ascertain ideas on

feasibility and application of coring equipment. The response rate was extremely low, however, a

few companies were identified that provided valuable information and perspectives. (A copy of

the survey is shown in Appendix 1).

A literature search only uncovered one additional bale coring technology, other than the one that

CWC viewed in operation in Sweden. As much technical and operational information as possible

was gleaned from the manufacturers and users of these two coring systems.

Due to the prohibitive cost of licensing or purchasing off-the-shelf equipment directly from the

manufacturer in Europe, CWC made the decision to build the equipment locally. Basic design

concepts were extracted from the literature search on the two bale coring technologies discovered

in use outside the US and from a few ideas presented in the survey results.

CWC then developed equipment specs and solicited a competitive bid to locate and contract with

a consultant to design and manufacture the equipment.

To facilitate data collection for contamination and moisture levels, the CWC purchased a certified

scale and moisture measurement device (See Appendix 2 for operating instructions for the

moisture meter). A comparison test between the oven-dry method and the moisture meter was

completed on wet paper samples. The test indicated that the moisture meter would provide an

adequate indication of moisture levels compared to the oven-dry method, for moisture levels

below about 20%. The operating instructions noted that the moisture meter is not accurate above

this moisture level.

The CWC also evaluated several software packages for data collection. Two of these options

included MS Excel™ and QI Analyst (produced by a company called SPSS). QI Analyst is

actually a statistical process control software package with the desirable feature of quick and

simple graphing of data. The disadvantage to QI Analyst is that it can only graph one variable (e.g.

% of prohibitives) on each graph. The disadvantage to using Excel is that a graph must be

created/or altered each time new data points are added. Data is transferable between the two

programs, so the final recommendation would be to collect data on logsheets similar to those found

in Appendix 3 and, depending on how data is to be presented, use Excel or QI Analyst according

to objectives for compiling data.

The CWC coordinated with the University of Washington's Industrial Engineering Program to

evaluate the statistical validity of using core sample data to represent an entire bale or lot of bales.

CONCEPT DEVELOPMENT

The initial concept for this project was spurred by a visit to a paper mill in Sweden that currently

uses bale coring technology to sample incoming fiber bales before the bales enter the repulping

process at the mill. At CWC's request, this equipment was temporarily retrofitted with a special

coring tip to test the possibility of coring of rigid plastic bales. Several samples were extracted

and analyzed from a PET bale and from plastic film bales. Several other European paper mills

using this technology have reported improved quality control and significant cost savings.

A smaller, portable bale coring unit is being used in South Africa and elsewhere to test the quality

of recycled fiber bales. This unit was designed and manufactured by the Institut fur Papier

Fabrikation in Germany. It is a very small unit, not really as sophisticated or robust as the unit in

Sweden.

In 1995 and 1996, CWC began working with the Chicago Board of Trade's (CBOT) Recyclables

Exchange, an on-line trading system established for recyclable commodities. The Steering

Committee raised the issue of dispute resolution for material that was sold through the Exchange

system but did not meet certain specifications. The idea of establishing sampling protocols and

testing methods to use in the case of disputes regarding material quality led to the application for

funding of development of bale core sampling.

The advantages to large paper mills that can implement a robust system to take core samples,

include:

• reduced time to obtain representative samples, and evaluate quality control;

• improved accuracy of tests; and

• continuous feedback to suppliers on the quality of delivered materials.

At the mill in Sweden, the equipment cores samples as the bales move along the conveyor toward

pulping operations. Each cored sample is collected, sorted for contaminants and non-specified

fiber grades, and then tested for moisture level in an oven-dry test method. Contamination and

moisture data from each sample is recorded in a database, and compiled in graph form for each

bale supplier. This allows easy and effective tracking of supplier performance and feedback to

suppliers on the quality of the material they provide.

From the reported successes in Sweden, the testimonies of usage of the smaller unit manufactured

in Germany, and the CWC prototype unit, it is evident that bale sampling of fiber and plastic bales

is technically feasible.

EQUIPMENT PROTOTYPE DEVELOPMENT AND SAMPLING RESULTS

The survey that was sent out at the onset of the project, despite a low response rate, provided some

useful information in developing specs for the equipment. A synopsis of the results follows:

Five of the of the nine respondents stated that bale inspection is a burden to theirparticular industry and the availability of a rapid sampling technique would behelpful to: (1) identify and control contaminant levels; and (2) address the issue offiber cost escalation due to high moisture content.

One respondent inspects plastic bales by visual inspection and does not breakapart the bales. The remaining respondents inspect paper bales using severalmethods, including:• Visual inspection -- four sides of bale (except for certain mills that may

require 6-sided visual inspection).• If suspicious material is found in the 4-sided visual inspection, one company

sends the bale to raw material sort line for break, resort, and rebale.• Break bale after weighing; hard sort entire bales (for contaminants).• Moisture probe into bale - bone dry samples (1st pass), if medium to dry,

pass, if > 5%, do oven-dry test.• Open bale inspection.• Pick contaminants from surface.• Require bale weight, density, and size from vendor.

The length of time to perform a typical bale inspection was reported to vary from afew minutes (e.g., with a moisture probe) to several hours to sort out contaminants.It usually takes 15 minutes for a visual inspection of a truckload of bales.

The number of bales inspected per shift, per truckload, per supplier or othercategorization scheme varies.• One respondent only inspects a number of bales as a special case.• A range of bale sampling frequencies were reported for moisture analysis:

from zero, to a range of 1 to 5% of incoming bales.• A range of bale sampling frequencies were reported for contaminant analysis

by sorting: ~0.1% of bales for contaminants (usually, 1 bale persupplier/month), and one outgoing bale per shift.

• One respondent checks all bales visually and another only visually checks 4%of their bales.

• One respondent inspects 1 bale/shift.

Most of the respondents agree on the necessity to report back to suppliers on thequality of their material. This regular feedback helps to keep the quality high andprevents deterioration of the bales.

One respondent suggested it would be important to have a portable coring unit tobe able to sample a number of bales without having to move them around in theplant.

Based on survey results, the technology/literature review, and other research conducted by the

selected contractor (PTL), the features of the first version of the equipment included:

• Portability;

• A 24” ram air cylinder which provided most of the thrust force into the bale (which

necessitated an ancillary air compressor for operation);

• 110 Voltage, Single-Phase power hookup;

• Control panel;

• Removable carbide-tipped bit for paper coring;

• Removable, high-speed-steel tips with scalloped edge for plastic coring;

• A jaw clamping system to hold the bale in place during drilling;

• 1 hp motor to rotate the coring tube and tip as it penetrated into the bale; and

• Air passage cooling tube inside the coring tube, in an attempt to minimize heat generation from

the friction of rotation and thrust into the bale. (Minimizing heat generation is critical,

especially in flammable materials such as bales of cardboard and paper. Furthermore,

excessive heat may cause erroneous moisture readings as some of the moisture evaporates

from the heat).

Certain components of the equipment were subcontracted out from PTL, including the operating

control panel, a jaw clamping system, and the manufacture of coring tips for the various recycled

material types.

The first version of the prototype equipment was completed in August 1997. Photos of this first

unit are shown in Appendix 4. The equipment was installed at a large recycling facility (Smurfit

Recycling Company located in Renton, Washington) that bales a number of recycled paper grades

and other commodities. The facility generates large, very dense bales (in the range of 25 – 30

pounds per cubic foot) of various paper grades.

The operational sequence for using this initial prototype follows:

♦ Equipment set-up (plug in, inspect belts, airline, and components, hook up to air compressor)

♦ Install correct cutter tip

♦ Position bale (may require pallets underneath bale to achieve good sample height)

♦ Position equipment for drilling location (avoiding bale wires)

♦ Secure bale in clamping jaws

♦ Apply wheel brakes

♦ Turn equipment on and drill

♦ Retract coring tube from bale

♦ Release clamping jaws and move equipment away from bale

♦ Use ejection rod from back end of machine to push sample into container (and/or directly intoair-tight sample retention bag)

♦ Label sample with date, bale identification, material grade, depth of penetration (measuredepth of hole in bale), and general quality observations.

♦ Measure moisture of bagged sample with the moisture meter

♦ Sort and weigh sample contents, including contaminant levels

The equipment was able to draw fiber samples, but not to the initial design depth of 24”. This first

test found that the air cooling tube inside the coring tube seriously affected the mobility of the

sample into the coring tube. Therefore, it had to be removed, despite possible heat generation

during drilling. Due to potential fire hazard with coring, a fire protection engineer was consulted

on an in-kind basis for recommendation on fire protection measures. A 5-gallon, multi-purpose

(4A:60B:C) fire extinguisher was purchased and attached to the equipment. The rating was

recommended to cover the danger of internal bale combustion, as well as any electrical fire

potential on an overloaded coring bit.

The thrust and torque were inadequate to core deep enough into the dense fiber bales. The

equipment was power-limited due to the electrical constraints of the 110 Voltage supply at the test

site, which limited the horsepower available to 1 hp electric motor. The facility's amperage was

also limited, which kept causing the circuit breakers to trip. With this limitation, using a

1 hp motor produced a fairly low rpm. Higher rpm and thrust are needed for dense bales such as

the ones produced by Smurfit.

During this phase, PTL was acquired by a larger company, and several of the PTL staff on the

project left the company. The lead engineer started his own company, Dynamark Engineering.

CWC pulled the contract from PTL and signed a new contract with Dynamark to finalize the

project.

Through various modifications and updates based on learnings from each test and samples taken,

the equipment was still unable to penetrate to the depth needed. After many CWC/Dynamark visits

to Smurfit to try small retrofits and upgrades to enhance bale penetration levels, Dynamark

returned the equipment to its own facility to incorporate larger-impact design changes and to

install a higher power motor if possible.

After trying a number of different machine configurations in attempts to optimize between the

advance (thrust) force and rotational speed of the cutter, we found that we could not feasibly

extract core samples from Smurfit’s old corrugated containers (OCC) and paper bales with the

power-limited situation. (Note: The Smurfit facility utilizes a large, single ram baler, and

produces OCC and other fiber grade bales with density of about 25 – 30 pounds per cubic foot

[pcf]. The initial intent was to sample OCC, #8 newsprint, sorted white ledger, and office pack.)

The log of equipment changes and experimentation during this phase are included in Table 1.

Table 1: Chronological Log of Equipment Design Changes and Sample Results

(From Inception of Project through March 1998)

Date Configuration History: Design changes and subsequent findingsBefore9/20/97

2-3/8” core tube diametervarious cutter configurations1 hp motor (1725 rpm capacity)air supply from 15 hp compressorthrust: 416 pounds max (noadvance rate control)89 rpm

Equipment installed at Smurfit.Cutter clogs as it goes a few inches into OCC bale.Cuts easily into rigid plastic bales (up to ~ 6").Removed initial cooling tube apparatus since the compacted balematerial expands as pushed further inside the coring tube. Expansionhinders material from being pushed further into the bale and alsoincreases difficulty in extracting sample from tube.The samples tend to twist with rotation of the coring tube -- andlong, twisted samples rather than small discs were achieved. Thedesired sample would be in the shape of the round discs.

9/20/97 Same configuration Equipment moved to Dynamark facility for modifications: Cutterclogs as it goes a few inches into OCC bale; cuts easily into rigidplastic bale.

9/24/97 2-1/4” cutter hole saw for OCC2-1/4” scalloped tip saw for plastic1 hp motor (1725 rpm capacity)air supply from Smurfit shop airthrust: 416 lb (no rate control)89 rpm

Test at Dynamark: Cores about 12” into plastic film bales. Samplesretained. Disc-shaped samples.Moved equipment back to Smurfit.Occasional trip of facility circuit breakers due to high amperage drawand difficulty getting beyond 4 to 6” into OCC bale. Slow advanceinto bale.

10/1/97 2-1/4” cutter hole saw1 hp motor (1725 rpm capacity)air supply from 15 hp compressorthrust: 416 lb (no rate control)157 rpm

Cutter grinds for ~30 seconds then slowly starts advancing into OCCbale. Occasional trip of fuses and facility circuit breakers.Some fiber gumming on teeth.Slow forward movement.Retention of some sample material inside bale.Installed data tracking software at Smurfit.

10/13/97 2-1/4” cutter hole saw6 hp gas motor (3600 rpm capacity)air supply from SmurfitThrust (uncalculated)2000 rpm

Attempted to increase power supply by installing gas-powered 6 hpmotor. Evaluated on OCC bale. Gas motor allows no control ofthrust into bale. The rotational speed is too high.Potential safety hazard during operation due to high speed; Potentialcombustion source due to high speed heat generation. High speedcaused severe wear to blade tips after only one use. Reinstalledprevious motor configuration.

10/17and10/22/97

1-3/4” diameter & adapter piece1 hp motor (1725 rpm capacity)air supply from Smurfit shop airthrust: 416 lb (no rate control)550 rpm

New smaller hole saw diameter cutter with tapered (2-1/4” down to1-3/4” – 60 degree taper) adapter. Motor still tripping due to highinitial gearing. Gummed teeth due to the small teeth. Hard toremove OCC from the sample tube. Only achieved about 6” depth.Discovered that the tapered surface increases resistant forces withadditional bale penetration.

Date Configuration History: Design changes and subsequent findings

11/12/97 2-1/4” cutter hole saw1 hp electric motor (3450 rpm)air supply from Smurfit550 rpm

Ordered and installed 2 hp motor. Regularly trips facility breakers,so cannot achieve any sufficient depth into bale.

12/2/97 2-1/4” carbide-tip saw (custom)2 hp electric motor (3450 rpm)air supply from Smurfitthrust: 416 lb (no rate control)550 rpm

Installed custom-designed core drill with carbide teeth. Initialpenetration yielded very good cut with no twisting of the sample.Again, tripped circuit breakers too frequently to achieve sufficientcoring depth. Some sample remains inside cored hole of bale.

12/16/97 Same Reduced speed to 500 rpm, added adjustable airflow orifice tocontrol thrust advance. Again, tripped circuit breakers toofrequently to achieve sufficient coring depth.

2/25/98 1-3/8 coring tube(new) 1-1/4” custom, tipped cutter1 hp motor500 rpm

Redesign/reinstall new coring tube assembly: torque problem solved;however, motor tripping at high-speed / high-thrust setting. Charredsample.

3/1/98 1-3/8 coring tube1-1/4” custom, tipped cutter1 hp motor250 rpm

Changed gear ratio & motor to reduce rotational speed. Reducedincidence of motor tripping, but new problem emerges. Since slowerrotational speed and same advance rate, more frictional heatgenerated. Fire produced in bale at drilling site. Coring tubepenetrates approximately 10” and firmly compresses and burns thesample so that sample components were unrecognizable.Cutter head extremely hot – potential burn/ safety hazard.

3/4/98 1-3/8” coring tube1-1/4” custom, tipped cutter1 hp motor500 rpm

Changed motor back and gear configuration back to give 500 rpm.Attempted to change/optimize advance rate. Same results as 3/1/98.Coring tube penetrates approximately 10” and firmly compressesand severely chars sample.Unsure how much sample retained inside bale.

3/18/98 1-3/8” coring tubePrototype 1 ¼” incising cutter1 hp motor500 rpm

Moved to plastic facility; more giving material on which to continuebeta testing the equipment.Effective coring into plastic film bale, however, too much sampledensification and compaction due to heat generation during drilling.Decision made to take equipment back to manufacturing facility andinstall a 3 hp motor, and implement some additional design changesto facilitate better drilling.

At Resourcing Associates, Inc., (RSA) on March 18, (refer to last entry in Table 1 Log), decent

samples were extracted from a number of different grades of polyethylene film bales, ranging in

bale density from 18 to 25 pounds/cubic foot. A composite film sample of two cored samples

from the bale was extracted. The sample depth was fairly shallow however, at about 16”

maximum penetration, and was deemed inadequate for representative sampling.

Moisture was measured with a meter, and the sample was sorted for contamination. Results are

found in Table 2. A small amount of fines, too small to sort, were not included in the

contamination sort data for this sample. From a quick visual inspection, the RSA staff believed the

base was primarily LDPE film. As it turned out from the sorting exercise, the major portion of the

sample was HDPE film! This indicates value in core sampling for quality control.

Photos of the sorted sample also shown in Appendix 5. Unfortunately, the bale was not sorted at

the time the sample was taken to correlate the composite sample with the cored sample.

During one of the sampling sessions at RSA, about 10” into an HDPE film bale, the coring tube

suddenly locked up and would not rotate. The coring tube had to be removed from the bale

manually, by pulling outward, and manually reversing the inbound rotational direction until the

tube was fully out. The problem was caused by a 15-foot long by 6-inch wide piece of upholstery

fabric from inside the bale that had wrapped itself around the coring tube. Thus, another

beneficial use for coring as a quality control method is discovery of internal bale contaminants.

Aside from contamination assessment, however, RSA stated that sampling analysis for resin

content in film bales may be a higher priority use of the equipment than analysis for contamination

or moisture content.

Table 2 – Film Sample Sorting Results (Excluding Fines Weight)

Sample ComponentWeight

Percentage

HDPE 47.5%

LDPE 8.2%Resins

LDPE Foam 4.9%

Rigid Plastics 9.8%

Tape 24.5%Contaminants

Other 4.9%

Moisture 6 %

At this point, RSA and CWC discussed at length the feasibility and practical use for this equipment

at their facility. They expressed a need for a sample that penetrates all the way through the bale,

and that three samples per bale would be required for representative data that would statistically

reflect the bale contents. The current equipment's design penetration depth was only 24". Since

bales typically range from 3 to 4' wide, the design of the equipment would have to be altered to

allow penetration all the way through. (However, at this stage, the longest sample attained was

only ~16". The equipment was unable to even yield a full 24" sample). Further troubleshooting

was necessary to attempt to improve coring efficiency.

RSA also suggested a sampling pattern of three holes penetrating through the entire bale, as shown

in Figure 2. Because the equipment was designed for portability, and because resources were

limited, the height of the core drilling tube in this configuration could only remain constant with

respect to the ground. Drilling at different heights would require a rather expensive elevator lift,

or that the bales be set on pallets or other platforms to achieve different drilling heights. This adds

significantly to the cycle time for obtaining samples.

Figure 2

Sampling Coring Pattern for Typical Bale

Direction of stratification

After the trials (as detailed in Table 1), and discussions with RSA, an equipment remodification

plan was developed to continue testing at RSA’s film plastic warehouse. Since this facility had

the availability of a 208-volt power supply (3-phase, 4-wire configuration), this would allow the

important design change to increase motor horsepower. More horsepower would provide higher

thrust and torque to penetrate the bales and an adequate coring rotational speed. Thus, the

equipment was moved to the Dynamark facility for renovation.

The design change and remodeling was quite extensive. The ram air cylinder was removed and

replaced with a screw-thread advance mechanism. The control system and connectors were

reconfigured for 208 V, 3-phase power. Lastly, the clamping jaws formerly used to hold the bale

in place during coring, were replaced with a simple winch that ties and tightens around the bale to

hold it in place. The coring tube (originally a permanently installed component) was replaced

with a 42”, removable coring tube. The remodeled equipment was moved back to the RSA facility

in July 1998. A sketch of the design is shown in Figure 3.

Figure 3: Top-Down View of Coring EquipmentFigure 3: Top-Down View of Coring Equipment

(Not to Scale)

Operation

♦ Equipment set-up: Install correct cutter tip

♦ Position bale (may require pallets underneath bale to achieve desired sample height)

♦ Position equipment for drilling location (avoid bale wires)

♦ Secure bale (either in forklift, or with cable wench)

♦ Apply brakes

♦ Turn equipment on and drill in

♦ Retract coring tube from bale

♦ Unsecure the bale, release brakes, and move equipment away from bale

♦ Remove coring tube from base plate

♦ Use rod to push sample from coring tube into container (and/or directly into air-tight sampleretention bag)

♦ Label sample with date, bale identification, material grade, depth of penetration (measuredepth of hole in bale), and general quality observations.

♦ Measure and record moisture of sample in bag (using moisture meter)

♦ Sort and weigh sample contents, including contaminants

A chronological account of events and learnings from trials with the second configuration of the

equipment are shown in Table 3.

Table 3: Chronological Log of Equipment Design Changes and Sample Results (From Installation at Re-Sourcing Associates to End of Project)

Date Configuration History: Design changes and subsequent findings7/20/98 1-3/8” coring tube, copper

1-¼” diameter incising cutter3 hp motorAdvance rate = 17”/minuteRotational speed ~ 350 rpm

Sample depth only about 6 – 12”. The core extraction was found to beinadequate because the advance rate of the coring tube into the bale wastoo slow, causing severe compaction and densification of the samples.

Substantial modifications were planned to increase the advance rate toabout 53” per minute, by changing the sprocket sizes.

8/5/98 1-3/8” coring tube, copper1-¼” diameter incising cutter3 hp motorAdvance rate = 54”/minuteRotational speed ~ 350 rpm

This trial, at the increased advance rate, resulted in high heat generationat the point of coring, which still caused the rigid and film plastic todensify and melt.

One trial with the carbide-tipped cutter on the rigid plastic resulted inexcessive fine generation and very rough edges on the cored samplepieces. This determined that the sharp-toothed, carbide tip wasinappropriate for plastic bales.

One sample contained a chunk of metal.

Another next modification of the equipment was planned to reduce therotational speed.

9/9/98 &9/29/98

(Finaltrials fortheproject)

1-3/8” coring tube, copper1-¼” diameter incising cutter3 hp motorAdvance rate = 54”/minuteRotational speed ~ 70 rpm(Machine guards installedaround the open sprockets forsafety)

During these trials, the rotational speed and advance rate appearedappropriate for minimizing sample densification and melting from thefrictional heat generated during penetration.However, the next problem cropped up. This new configuration of theequipment replaced the bale ‘clamping jaws’ with a cable winch tosecure the bale. The cable was inadequate in holding the bale securely inposition during drilling. The bale moved, and, the side of the baleclosest to the coring equipment lifted up off the ground; both of whichcaused the coring tube to contort. In an attempt to alleviate thisproblem, a forklift was used to hold the bale securely in place.The forklift stabilized the bale in place, but then the brakes on thewheeled cart holding the coring equipment assembly were not strongenough to hold the equipment in place. The resistant forces generatedduring drilling pushed the equipment back away from the bale. Wheelchocks were also unable to hold the equipment in place.Due to the inability to stabilize both the bale and the equipment withrespect to each other, the coring tube permanently bent out of alignmentand drilling had to be concluded.

SAMPLING PROTOCOLS

In the recycling industry, establishing acceptable quality procedures that remain cost-effective,

considering the fairly low value of recyclable materials, is a fine balance. For many recyclers, it

has been acceptable to sacrifice truly statistically valid quality control measures, with methods

that are less expensive to implement, but still gather enough data to achieve some level of quality

metrics. For example, due to issues with the small sample population in a given lot of bales (e.g.

~30 per truckload), it may require up to 20 bales to be sampled out of the 30 for adequate

statistical representation. This is obviously uneconomical to achieve, due to the low profit margin

on most recycled feedstocks.

It is believed that core samples of recycled bales would allow a higher level of statistical validity,

while drastically reducing inspection costs associated with breaking and sorting bales.

At recycling plants or end-product manufacturers that receive bales for use in product manufacture,

quality data is often gathered by outside visual inspection, or by breaking and inspecting bales

(which can range from 300 to 3,500 pounds each). Bales are bulky, heavy, difficult to handle,

expand when broken, and the separated material must be replaced back into the feed stream.

Even if a small number bales are opened per shipment, or per day, (or one per month for each

vendor, etc.) the cost can be significantly expensive. Some have explored sampling plans and

inspecting for a portion of the bale only, such as one-fourth of the bale (Dorland & Yin)1. Due to

potential non-homogeneity of bales, with likelihood of concentrations of contaminant(s) in one

section of bale, or contaminants deliberately hidden in the interior center of bale, obtaining a

homogeneous sample is difficult.

Employing a sampling scheme as extracting a portion of the bale (e.g. ¼ of bale), or sampling by

coring, may not provide a representative sample of the entire bale contents. However, if enough

historical data is gathered (e.g. segregated for on specific grades of material, or by supplier, or by

1 Dorland and Yin concluded from experimental and statistical analysis that ~ ¼ (25%) of a baleby weight would be an adequate sample size and that 1/8 of bale as a sample introduced muchmore variability (and less certainty of) information.

shipments to one customer), the possibility of using coring samples to go to a statistical process

control method or reduced sampling plans, might provide adequate data for quality certification of

the material.

Studies with baled paper involving comparisons of various quality control test methods that

maintain bale, indicate that the minimum sample size is a one-quarter contiguous section of a bale.

It is apparent that not only the size of the sample is critical, but also the location of the sampled

material -- representative samples cannot be obtained without sampling interior sections of the

bale.

The following three components are important for developing a suitable sampling protocol for

incoming bales.

• set up inspection lot from each shipment or receipt of shipment and for each grade to be

inspected;

• establish acceptance quality; and

• select sampling plan

Because statistical issues are important and beyond CWC’s expertise area, the CWC utilized the

School of Industrial Engineering at the University of Washington, to assist in developing a template

sampling plan to use in core sampling of bales for this project.

Their conclusions concerning the sampling plan come from the test on a population mean with a

one-tailed test. This formula gave the sampling frequency for a population, given its maximum

allowable and historical mean value. By using the one-tailed test at a 97.5% confidence level, in

conjunction with a proportional ratio of the bale to sample size, they developed a sampling plan

considered to represent the entire population. The plan was based on actual bale weight and

density data from typical paper, OCC, and rigid plastic bales from Jefferson Smurfit Recycling

Company, and typical film plastic bales from RSA.

The basis for their recommended sampling plan follows. The appropriate number of samples to be

drawn is an important factor. The number of samples is dependent on the size of the bales, the

level of contaminant allowable in the bale, the diameter and length of the sample, the level of

statistical confidence required, and the standard deviation in the sample. The equation used to

derive the number of samples is based on the test of hypothesis about a population mean of a one-

tailed test from the following formula:

Z = (A - µ) / ( F - /n)

Where, Z = test statisticµ = estimated (mean) bale contaminateA = allowable bale contaminateF = sample standard deviationn = sample size

To use this formula, a normal distribution of contaminate is assumed. In order to apply this

formula, the equation is rearranged to solve for "n," and includes a population proportion constant,

µ, based on the sample and bale weights. By rearranging the above formula and adding the

proportionality constant, the formula for determining the number of samples to be taken from a bale

of a specified weight is as follows:

N = [(Z*F*D)/(AD - µD)]2/D

where,

D = weight of sample/weight of baleAll other variables remain the same as defined above.

Three sampling plans were formulated taking into consideration various confidence levels: Z

based on 95% confidence (" = 0.05), Z based on 97.5% confidence (" = 0.025), and Z based on

99% confidence (" = 0.01). Table 4 provides the number of samples to be taken out of each bale

for various levels of confidences.

Table 4 Number of Samples per Bale for Various Confidence Levels

% Confidence 95% 97.5% 99%Z Values 1.64 1.96 3.09

CommodityStandard

Deviation (FF)Number of

CoreNumber of

Core SamplesNumber of

Core Samples

Samples (n) (n) (n)ONP 0.4 1 1 3OCC 0.4 1 1 2Mixed Waste Paper 0.4 1 1 3Office Pack 0.4 1 1 3HDPE Bottles 0.4 5 7 16PET Bottles 0.4 6 8 20Plastic Film 0.4 5 7 16

Because the beta testing phase of this project did not yield enough good sample material to test out

the recommended sampling plan from the UW study, and because no comparisons of core sample

data to actual bale content data was completed, this sampling plan was not used or field tested.

An additional task for statistical analysis would be required to establish acceptance quality

criteria for the samples, for each individual grade of baled material evaluated. The acceptance

quality criteria, when established for coring sample analysis, would indicate when to accept or

reject bales based on sample quality. Ultimately, the end product or pulping process will also

stipulate what contaminants and allowable levels are acceptable.

Acceptance quality criteria can also be determined by historical statistics, or by standardized

specifications. For example, in the paper industry, paper recyclers and manufacturers take many

grades and combinations of grades of recycled paper. Contaminants and moisture are the two

primary material quality issues in using recovered paper. The Institute of Scrap Recycling

Industries (ISRI) publishes a standard specification for many grades of recycled paper, which

define prohibitives and outthrows for each grade, and specify that total prohibitives must not

exceed 0.5% by weight, total outthrows must not exceed 2.0%, and the combined total of the two

must not exceed a combined total of 2%.

RESULTS AND RECOMMENDATIONS FOR APPLICATION AND FINALIZING

CORING TECHNOLOGY EVALUATION

This project was essentially more of a research & development project, than a technology

evaluation, as originally scoped. The primary reasons being:

♦ purchase of off-the-shelf coring technology was cost-prohibitive given the funding for this

project, thus, the equipment had to be designed from scratch.

♦ the competitive bid process resulted in a consultant with equipment and mechanical expertise,

but no applicants had any experience in coring technology, thus much experimentation was

required with respect to the coring mechanism.

♦ the portable nature of the equipment (verses an in-line installation) limited the ability to

stabilize the bale with respect to the equipment.

♦ each of the baled materials exhibits different characteristics and different resistant forces,

therefore a configuration that works for one material may not work as well in another material

type.

Despite the R & D nature of the project, the project did accomplish the following:

• determined power requirements necessary to be able to core into recycled bales.

• determined cutter diameter, teeth and blade configuration of the cutting edge to minimize effect

on the extracted sample (to reduce friction or shearing action, that could tear or distort the

outer diameter of the sample).

• optimized different drill bit designs/materials for effective use with the different baled

materials.

• minimized heat generation during the drilling cycle, to avoid moisture evaporation, or

degradation/melting of the outer diameter of the plastics samples.

• developed data collection logs and simple graphing methods for bale coring, and sample

graphs for recording and feedback reporting to suppliers or customers (Appendix 3).

Thus said, the learnings and recommendations from the project are presented below.

Force Considerations for Equipment Design

Bales exhibit significant resistant force during bale penetration, both from torsional and thrust.

The resistant forces during coring will vary with material properties, density or compaction rate of

the bale, advance rate, cutter diameter, speed of revolution, and degree of compaction of the

sample inside the coring tube.

In the case of the rigid PET bale, with the final configuration of the equipment, the estimated,

(worst case) torsional force requirement is 220 foot-pounds, and the estimated, (worst case) thrust

force requirement is 6,700 foot-pounds. This force is significant, and requires more power than a

110 volt, single-phase power supply can provide (such as used in the initial trials with the

equipment). From trials with the final configuration of the equipment, the 208 volt, three-phase

power supply, which supports a 3 horsepower motor, appears to provide adequate strength to

penetrate most bales.

Cutter Design

A number of different cutter tips were tested in the course of this project, including standard hole

saws (available at typical hardware stores). Different baled material properties affect cutting

efficiency and behavior. Different blade types affect the quality of the sample (e.g., smooth edges

on the cored discs, fines generation, etc.). The standard hole saw is not manufactured with a high-

speed steel, and in general, was not durable enough for bale coring application.

In trials throughout this project, we found that the paper and OCC were fairly abrasive materials,

and tended to wear the blade tips quickly. The frictional heat generated during drilling also

contributed to blade wear. Therefore, consulting with a tooling manufacturer (Emerald Tool,

Seattle, Washington) was necessary.

Emerald designed high-speed steel cutter heads, with embedded carbide-tip blades for use on the

paper and OCC bales (refer to Figure 1). The carbide tips were very durable and hard, and

seemed to create a desirable cut into the paper and OCC bales. When tested on plastic bales, the

carbide-tips tended to ‘chew’ up the outer edges of the cored discs, and generated significant fines.

Thus, the plastic responded better to the scalloped-edge cutter, made of high-speed steel, with

three or four rounded peaks around the perimeter of the tip.

Sample Extraction from Bale and Coring Tube

Throughout the project (in all equipment configurations), two problems occurred with respect to

sample extraction. First, the sample material compacted densely into the coring tube, which made

extraction of the sample from inside the tube difficult. This also added significantly to the cycle

time for the sampling process. In some cases, the coring tip had to be removed to get the sample

out of the tube and the bit itself.

Second, upon removal of the coring tube from the bale, sample material often remained in the

cored hole of the bale. This sample material was very hard, if not impossible, to remove from the

bale, due to the small hole and the depth of the hole.

The larger diameter coring tube and bit (2-1/4” diameter as in first configuration) may lend itself

to easier sample extraction from the bale and the coring tube than the 1-3/8” diameter tube and bit

(second configuration). However, the larger diameter tube, the higher the power requirement.

These trials did not attempt to run the combination of the 2-1/4” diameter tube and the 3 hp motor

(208 volt, 3-phase).

Sample Densification, Melting, or Charring from Frictional Heat Generation

Frictional heat generated during coring affected the moisture evaporation rate and the quality of the

sample. Many of the plastic samples in earlier trials densified or severely melted. In some cases,

the plastic film melted into a ‘plug’ resembling an extruded plastic product similar to plastic

lumber!!! This plug typically did not occur until about 10” or deeper into the bale, where the

advance rate would slow some, due to the increasing forces as the tube moves into the bale. In

other cases, the outer edges of the disc-shaped samples would melt together enough that the sample

could not be adequately separated for sorting. This effect was also noted on the plastic samples

from trials with the Sweden equipment. A few of the paper samples were charred around the

edges.

The original idea of an air-cooling mechanism inside the coring tube, which was installed on the

first configuration of the equipment, was good for heat removal, but significantly impaired sample

extraction from the tube. With subsequent trials with different rotational speeds and advance

rates, a variety of results occurred with respect to heat generation on the cored sample.

The final configuration of the equipment, utilizing an advance rate of about 54 inches per minute,

and a rotational speed of about 70 revolutions per minute (rpm), seemed to minimize heat

generation in the plastic bale during coring. This setting was not attempted on paper bales.

Industry Application and Interest

The original project scope entailed beta evaluation of this equipment at local recycling facilities

or material recovery facilities (MRF) instead of using a higher-end user (e.g., paper mill or plastic

reprocessor) as a beta test site. Also, there are no recycled paper mills in proximate distance from

the CWC location.

One viable use in a recycling facility or MRF would be to sample baled material just prior to

shipment, and be able to send the results of the sample analysis to the customer to demonstrate the

material quality level. Note: Alternatively, however, this process may not have added value for

recycling facilities that pull (loose) representative sample(s) from various processing points

and sorting lines to evaluate the material for quality and moisture content. In these cases, core

sampling from a bale may not provide any additional, useful data.

There are mixed opinions about the utility of bale coring technology throughout the industry. Many

recycling and baling facilities are very interested in a system to monitor the incoming and outgoing

material quality, especially if the system boasts a short cycle time to obtain good data, and can

replace a full bale sort inspection method. On the other hand, the small profit margin on

many recycled commodities may not justify the capital expenditure (estimated at about $20,000 for

the portable unit) and the added operational costs to implement bale coring at these types of

facilities.

Most facilities are wired for 110 V, single-phase, while some may have higher volt, higher phase

wiring for large equipment. The power supply requirement (208 V, 3-phase) may limit use of the

coring equipment at recycling or baling facilities, or require a wiring upgrade to be able to install

outlets with higher volt power. Although most recycling facilities have a few or several outlets

wired for 220/3-phase power for their large balers, these outlets may be utilized by the baler or

other large equipment and not readily available for coring equipment.

Some paper mills and large, profitable processors or manufacturers that could install an in-line

bale coring system that extracts samples as the bales move through the processing line, may be

willing to spend the capital for a system that could prevent contaminated material from entering the

manufacturing or pulping process. This would also allow quality control and feedback to their

suppliers. Yet, there is the statistical issue of whether a few core samples from a bale would truly

represent the batch or lot of material. This may be especially true in the case of PET, where one

or two polyvinyl chloride (PVC) bottles in a bale, which could ruin an entire batch of recycled

PET material, could easily be missed by one or two core samples of a bale. Furthermore, special

measures for the sample sort would be required (e.g., UV light) to identify PVC in the PET sample,

since PVC is similar in appearance to clear PET. For example, one PET processor stated that

plastic

Cycle Time for Sample Extraction and Analysis

The cycle time would have to be fairly short for most potential end users to consider implementing

bale coring as a quality control system. The current configuration of the portable equipment

requires the minimum estimated cycle time shown in Table 5 for one cored sample. This estimate

assumes no process interruptions occur, for instance, the incident when the equipment locked up

due to the fabric strip contaminant which had wrapped around the coring tube. In the case of RSA,

who indicates that three separate cored samples at different heights from each sample bale are

required, the overall cycle time with this configuration would likely be a minimum of 45 minutes

per bale to allow for height adjustment between sample extractions.

The additional time to analyze the sample for moisture and content varies greatly. The moisture

meter allows quick readings for moisture levels, while the oven-dry method may require an hour

or so. The time required to sort for sample contents depends on the amount of material in the

sample (e.g., depth of the sample, and whether or not the sample is a composite of several cored

samples), the level of contamination, and the material itself. A cored film plastic sample requires

manual pulling apart of the film, as it tends to stick readily to itself and other constituents. In the

case of the composite film sample sorted at RSA, a fair amount of tape (contaminant) had to be

pulled apart from the film. This sample weighed about 0.3 pounds and took 3 person-hours to sort.

The rigid plastic and paper sortation would not take nearly as much time, likely about 10 to 20

minutes per individual core. Weighing and recording the content levels would require an

additional few minutes.

It is unknown whether this full cycle time, for sampling and analysis, would be acceptable to those

in the industry who want to implement better quality control for baled materials.

Table 5: Estimated Cycle Time for One Cored Sample from a Bale

Operation Time (Minutes)

Equipment set-up: Install correct cutter tip 1.5Position bale (may require pallets underneath bale to achieve goodsample height)

1 – 3

Position equipment for drilling location (avoid bale wires) 1Secure bale (either in forklift, or with cable wench)(Note: previous configuration utilized clamping jaws with estimatedsimilar cycle time)

2 – 4

Apply brakes 1

Turn equipment on and drill in (assumes coring can go in full design depthof 42 inches).

1

Retract coring tube from bale(Note: Previous configuration retracted much quicker with the air ramcylinder rather than the screw feed mechanism).

1

Unsecure the bale and move equipment away from bale 2

Remove coring tube from base 0.5Extract sample from coring tube into tub (and/or directly into air-tightsample retention bag)

1-2

Label sample with date, bale identification, material grade, depth ofpenetration (measure depth of hole in bale), and general qualityobservations.

1

Total Estimated Sample Extraction Time 13 – 18 Minutes

Additional Evaluation Recommendations and Needs

Currently, the equipment is inoperable because during the last trial, the shifting of the bale and

equipment during drilling caused misalignment and subsequent failure of a few components.

Recommended design changes to make this equipment operational include the following:

♦ repair failed components.

♦ reinstall clamping jaws which stabilize the equipment and bale.

OR

♦ design fixed stations for the bale and equipment so that neither will move as a result of

resistant forces generated during drilling.

♦ replace the copper coring tube with a stronger metal, such as stainless steel.

Additional recommended, but optional design changes to reduce cycle time and make this

equipment more functional, include the following:

♦ improve the sample ejection mechanism.

♦ allow for height adjustment of the bale for drilling at different height positions on bale.

♦ increase the diameter of the coring tube to a minimum of 1-3/4”.

When the equipment is fully operable, evaluation of the coring methodology should be monitored

and compared with conventional bale breaking inspection for the following metrics:

• Cost of inspection (labor, materials, etc.).

• Correlation of contaminant levels between sample and entire bale.

• Inspection result documentation (material quality reports from the mill to the suppliers).

Follow-On Research and Development

As a follow-on to this project, the CWC plans to seek additional funding to complete the pilot

testing of the coring technology. This may occur through additional grant funding, (e.g., the Small

Business Innovation Research grant, etc.), or by seeking a manufacturer or fabricator partner

through which the CWC could finalize testing of the technology.

The CWC will produce and publish a fact sheet on the results of the project to date, which will be

available for review on the CWC website at www.cwc.org, and via the EPA and National Institute

for Standards and Technologies’ (NIST) “Source” websites. Future work on this project will

also be documented and posted at the same website locations.

REFERENCES

Dorland, D. & Yin, K. "Application of Acceptance Sampling to Scrap Paper Inspection. "Progress in Paper Recycling. February 1995.

Gottsching, L. & Phan-Tri, D, "Waste Paper Core Driller." (Unknown periodical).

Jackson, P. "Wastepaper Characteristics for Quality Control." TAPPI Press, PaperChem 61 10962; 1990.

APPENDICES

Appendix 1 Survey (Query of Interest for Beta Test Sites for Bale Coring Technology)

Appendix 2 Operating Instructions for Moisture Register Product

Appendix 3 Quality Data Logsheet for Plastic Bale Cored Samples

Appendix 4 Photos of First Version of Equipment

Appendix 5 Photos of Second Version Equipment

Appendix 6 Photos of Samples

Appendix 7 Example Graphs of Simulated Core Sample Data for OCC

APPENDIX 1: Survey

Query of Interest for Beta Test Sites for Bale Coring Technology

Introduction: The Clean Washington Center (CWC) is working on an EPA-funded project to prototype andevaluate a bale sampling system that does not necessitate bale disassembly. The proposed equipment willcore a sample from an intact bale of paper, plastic bottles and/or plastic film, for the purposes ofdetermining moisture and contaminant levels.

We are conducting a preliminary survey of interested participant(s) from the plastic and paper recyclingindustry, who would be willing to beta test this type of equipment at their facility for a period of two to fourmonths. We wish to compare the method of breaking bales for inspection vs. coring bales for inspection.We are interested in comparing costs, and moisture and contamination data between the two methods.

Would you mind answering a few questions?

Name and Title ____________________________ Company _______________________Description of Facility Capabilities _____________________________________________Address __________________________________________________________________Phone _________________________________ Fax _____________________________E-mail address ____________________________

Is bale inspection a burden to your industry? Do you see a need in the plastics industry for expedient balesampling equipment that does not require bale disassembly for inspection? Why or why not?

Do you currently inspect plastic bales? Paper bales?

What inspection procedure(s) do you use? Whole bale? 1/4 bale? etc.

How long does a typical bale inspection take?

Who inspects?

How many bales do you inspect? (% of bales in lot, or # bales/hour, etc.)

What do you do w/ bale material after broken?

How frequently do you discount after bale disassembly?

Any need for reporting back to suppliers on the quality of their material?

Are you interested in testing such a piece of equipment at your facility, at no cost other than labor?

Appendix 2:

OPERATING INSTRUCTIONS FOR MOISTURE REGISTER PRODUCTMODEL DC-2000-BP (Part No. 552296)

INTRODUCTION: The DC-2000-BP instrument measures direct current resistance in baled paper andrelates that measurement to moisture content. The meter employs a specially programmed Micro-Computer Unit to make accurate DC resistance measurements, compute the moisture content, and displaythe results on a direct reading Liquid Crystal Display.

HANDLING: While the instrument will withstand harsh field use, it must still be handled as a preciseelectronic instrument, and be kept clean and dry. Handle the connecting cable carefully; the wires in thiscable must remain well insulated, without punctures or tears.

RANGE: This instrument has been designed and calibrated for testing moisture in paper bales made up ofscrap materials. The output display reads directly in percent moisture content in the range of 5 weightpercent to 25 weight percent. For wet material that is above 25% moisture content, the meter will likelyprovide readings of 24 to 25 weight percent.

ACCURACY: The moisture reading was derived from an average calibration curve made up from severaldifferent types and weights of paper. For this, and other reasons discussed below, a high degree ofaccuracy should not be expected with this instrument. However, paper can easily be graded as normallydry, fairly damp, or definitely wet, merely by the readings of the instrument.

When using this instrument for baled material, the variation of paper stock and bale compaction, as wellas the individual contact between sample and probe, limits the ability to achieve high accuracy. It isrecommended that several readings be taken on each sample bale, and averaged for an overall balemoisture content. The instrument detects interior high-moisture locations within bales that are notapparent on the exterior of the bale.

When using this instrument for bagged samples of baled material, the variation in paper stock and directcontact between sample and probe also limits the ability to achieve high accuracy. Additionally, themoisture of the sample may not be evenly distributed. Thus, an average moisture value should becalculated from at least three readings on each sample.

DIRECTIONS:

1. CONNECT CABLE. Connect and tighten the cable between the instrument and probe. 2. TURN INSTRUMENT ON. Hold the probe so that it does not touch any material. Turn the

instrument ON by pushing the panel-switch up to the on position. When the instrument is turned ON,it performs a self-check with the display showing 5 + 1. If higher readings are displayed, turn theinstrument off, clean and dry the electrode or cable (it may be contaminated or wet). Turn theinstrument ON again and check to ensure the display shows 5 + 1.

2. CALIBRATION: The DC-2000-BP Standard (disk-like object with two screws) is designed to

provide a constant and repeatable load that verifies the operation of the instrument, cable andelectrode probe. Clean and dry the electrode and standard if wet or dirty. Place the DC-2000-BPelectrode probe across the screws as detailed by Figure 1. Ensure that the second part (below theinsulator) makes contact with the second screw. If calibrated properly, the display will read 12.0 +

1.0 %. If other values are displayed, check again. If needed, contact Moisture Register Products forcalibration service.

3. TAKE READINGS. The actual moisture reading occurs across the insulated portion of the probe,

about 1-1/4" from the pointed tip. Thus, ensure this area of the tip is in good contact with the samplematerial.• For bales: Push the electrode straight into the paper bale. If the area is too dense to insert the

probe, try another sample location. Record reading. Several sample locations and readings arerecommended for each bale.

• For bagged samples: Push the electrode into the cored sample in the sample bag. From outsideof the bag, manipulate the sample so there is good contact between the critical area of the probe(1-1/4" from the pointed tip) and the sample. Record reading. Repeat for a minimum total ofthree readings per cored sample, at different locations within the bagged sample. Record theaverage reading for each sample.

4. END TESTING. Turn power OFF to prevent damage to the instrument should the battery discharge

and leak.

MAINTENANCE:• Keep the insulated portion of the probe clean at all times,

as well as the plastic inserts in the connectors of the probe,cable and instrument. Accumulation of dirt on theseinsulators can cause resistance leakage and erroneousresults. Use a quality grade of denatured alcohol toremove dirt and grease from the instrument or electrode.Ensure dry before subsequent use.

• The meter operates from a single 9 Volt battery which willlast over 100 hours. When the battery is ready forreplacement, the display will show a reading of "99". Analkaline, 9 Volt battery is recommended for longest batterylife. To replace the battery, remove the lower half of the instrument enclosure. Unscrew the fourscrews visible on the bottom of the unit. Remove the bottom case, and lift the battery from itscompartment. Remove the connector from the dead battery and snap it on to the replacementbattery. The instrument is protected against reverse battery polarity, but if the battery is accidentallytouched to the connector the wrong way, this will greatly reduce battery life. When replacing thescrews, tighten snugly but do not over-tighten to avoid stripping the screws threads. NOTE: If theDC-2000-BP is to be stored for a long period of time without use, remove the battery.

SERVICE. If other servicing of the DC-2000-BP is required, please contact Moisture Register Productscustomer service at (909) 392-5833 or FAX (909) 392-5838.

SPARE PARTSPart Number Description552077 DC-2000-BP Electrode532876 DC-2000-BP Cordura Nylon Carrying Bag532312-005 9 Volt Battery552296 DC-2000-BP Instructions MRC005566 Cable

Figure 1: Calibration CheckPosition

Standard

Screws

Probe

APPENDIX 3: Quality Data Logsheet for Plastic Bale Cored Samples

Date Bale Total Grade Composite Reduced % of total Cumulative % % % % Time to CommentsID

NumberBale

WeightSampleWeight

SampleWeight

BaleWeight

SampleDepth

(inches)

ResinContaminant

Non-ResinContaminant

Moistureof Sample

Moistureof Bale

Collect/AnalyzeSample

APPENDIX 3: Quality Data Logsheet for Paper Grade Bale Cored Samples

Date Bale Total Grade Composite Reduced % of Total Cumulative % % % % % Time to CommentsID Bale

WeightSampleWeight

SampleWeight

BaleWeight

SampleDepth

(inches)

ProhibitivesContent

OutthrowsContent

Outthrowsand

Prohibitives

Moistureof Sample

Moistureof Bale

Collect/AnalyzeSample

APPENDIX 4: Photos of First Version of Equipment

Cutting Bit Experimentation

Drive System for Coring Tube (2 1/4" tube diameter)

Control Panel Wiring

Control Panel Face

APPENDIX 5: Photo of Second Version Equipment

Screw Feed Mechanism (1 1/4" coring tube diameter)

APPENDIX 6: Photos of Samples

HDPE Film (1¼" diameter)(showing densified core into a "log" rather than individual core discs)

OCC (2 3/8" diameter)PET (~1" diameter)

(from trials with Swedish unit

HDPE Film (1¼" diameter)

APPENDIX 6: Photos of Samples

Mixed Waste Paper Sample OCC Sample (2 3/8" diameter sample) (showing how material was Achieved very clean cut. twisted by shear forces, rather

than cored into disc shapes)

OCC Sample (showing excessive fines generation)

APPENDIX 7: Example Graphs of Simulated Core Sample Data for Old Corrugated Containers (OCC)(USL = Upper Specification Limit)

final technical u. s. epa: bale coring technology projectinfohouse.p2ric.org/ref/13/12464.pdffinal...

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