Parr Instrument 6200 User Manual
6200
Isoperibol Calorimeter
Operating Instruction Manual
For models produced after October 2010
585M
Table of Contents6200
Preface 4
Scope 4
Related Instructions 4
Purpose 4
Customer Service 4
Explanation of Symbols 5
Safety Information 5
Intended Usage 5
General Specifications 5
Environmental Conditions 6
Provisions for Lifting and Carrying 6
Cleaning & Maintenance 6
Getting Started 6
Chapter 1 7
Concept of Operation 7
Overview 7
Removable Bomb 7
Removable Bucket 7
Dynamic Operation 7
Full Microprocessor Based Process Control 8
Full Microprocessor Based Data Acquisition and Handling 8
Flexible Programming 8
Chapter 2 9
Installation 9
Environmental Conditions 9
Required Consumables, Utilities and Power Requirements 9
Filling the Jacket Reservoir 9
Power Connection 9
Jacket Cooling Water Connection 9
Tap Water Cooling 10
Cooling with the Water Handling System 10
Oxygen Filling Connection 10
Printer and Balance Connections 10
Standardizing the Calorimeter 10
Swagelok Tube Fittings 11
Chapter 3 15
Instrument Description 15
Types of Controls 15
Menu Keys 15
Control Keys 15
Chapter 4 17
Program Installation & Control 17
Software Installation 17
Default Settings 17
Revising Default Settings 17
Chapter 5 21
Operating Instructions 21
Operating the 1108P Oxygen Combustion Vessel 21
Operating the Filling Connection 21
Operating the Calorimeter 21
Samples and Sample Holders 23
Combustion Aids 23
Oxygen Charging Pressure 23
Combustion Capsules 23
Foodstuffs and Cellulosic Materials 24
Coarse Samples 24
Corrosive Samples 24
Explosives and High Energy Fuels 24
Volatile Sample Holders 24
Poor Combustion 25
Chapter 6 27
Corrections & Final Reports 27
Entering Corrections and Obtaining the Final Report 27
Manual Entry 27
Fixed Corrections 27
Chapter 7 29
Reporting Instructions 29
Report Option Section 29
Report Generation 29
Net Heat of Combustion 29
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Table of Contents
Chapter 8 31
File Management 31
Clearing Memory 31
Removable SD Memory 31
Chapter 9 33
Maintenance & Troubleshooting 33
Oxygen Bomb 33
Jacket Temperature Troubleshooting 33
Fuses 33
6200 Calorimeter Error List 33
Appendix A 35
Menu Operating Instructions 35
Calorimeter Operation Menu 35
Temperature vs. Time Plot Screen 35
Temperature Plot Setup 36
Operating Controls Menu 37
Program Information and Control Menu 38
Calibration Data and Controls Menu 39
Thermochemical Calculations Menu 41
Data Entry Controls Menu 43
Reporting Controls Menu 45
Communication Controls Menu 45
File Management 47
Diagnostics Menu 48
Appendix B 49
Calculations 49
Calculating the Heat of Combustion 49
General Calculations 49
Thermochemical Corrections 49
ASTM and ISO Methods Differ 50
Thermochemical Calculation Details 51
Acid and Sulfur Corrections 51
ASTM Treatment for Acid and Sulfur 53
ISO Calculations 53
Spiking Samples 54
Conversion to Other Moisture Bases 54
Conversion to Net Heat of Combustion 54
Appendix C 55
Standardization 55
Standardizing the Calorimeter 55
Standard Materials 55
Automatic Statistical Calculations 55
Appendix D 59
Communications Interfaces 59
Printer Port 59
Balance and Port Input Driver Specifications 59
Mettler 011/012 Balance Interface 59
Sartorius Balance Interface 59
Generic Interface 60
Ethernet Interface 61
Samba Server Feature (Optional) 62
Bar Code Port 70
Network Data Services 70
Appendix E 71
Technical Service 71
Return for Repair 71
Appendix F 73
Parts Lists & Drawings 73
Principal Assemblies in Calorimeter 73
Parts List for A1279DD2 Controller Assembly 73
Parts List for Temperature Control Assembly 73
Parts List for A1284DD2 Stirrer Hub Assembly 74
Parts List for Water Tank Assembly 74
Parts List for Cooling Water Supply 74
Parts List for Oxygen Filling System 74
Part List for 6200 Stirrer Motor and Drive 74
Spare and Installation Parts List* 74
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Parr Instrument Company
Tables
Table 4-1 6200 Factory Default Settings 18
Table B-1 Settings for ISO & BSI Methods 52
Table C-1 Calorimeter Control Limit Values in J/g 56
Table C-2 Calorimeter Control Limit Values in cal/g 57
Table C-3 Calorimeter Control Limit Values in BTU/lb 58
Table D-1 6200 Data File Naming Convention 60
Table D-2 6200 Calorimeter Run Data Template 60
Figures
Figure 2-1 Swagelok Tube Fittings 11
Figure 2-2 6200 Calorimeter Back Panel 12
Figure 2-3 Closed Loop Configuration with 6510 13
Figure 2-4 Open Loop Configuration with Tap Water 13
Figure 2-5 Open Loop Configuration with 1552 14
Figure 5-7 Combustion Capsule with Adhesive Tape Seal 25
Figure F-1 6200 Isoperibol Calorimeter Cutaway Front 75
Figure F-2 6200 Isoperibol Calorimeter Cutaway Rear 76
Figure F-3 A1279DD2 Control Schematic 77
Figure F-4 Oxygen Solenoid Assembly & Fittings 78
Figure F-5 Water Tank Assembly 79
Figure F-6 A1311DD Circulating Pump Assembly 80
Figure F-7 Temperature Control Assembly with Fittings 81
Figure F-8 A1284DD2 Stirrer Hub Assembly 82
Figure F-9 Stirrer Motor Assembly 83
Table of Contents6200
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Preface
Preface
Scope
This manual contains instructions for installing and
operating the Parr 6200 Calorimeter. For ease of use,
the manual is divided into nine chapters.
Concept of Operation
Installation
Instrument Description
Program Installation & Control
Operating Instructions
Corrections & Final Reports
Reporting Instructions
File Management
Maintenance & Troubleshooting
Related Instructions
Additional instructions concerning the installation
and operation of various component parts and peripheral items used with the 6200 Calorimeter have
been included and made a part of these instructions.
No. Description
201M Limited Warranty
418M 1108P Oxygen Combustion Vessel
207M Analytical Methods for Oxygen Bombs
230M Safety in the Operation of Laboratory
and Pressure Vessels
483M Introduction to Bomb Calorimetry
Additional instructions for the printer, cooler, and
water handling systems are found in the respective
package and should be made a part of this book.
Subsections of these chapters are identified in the
Table of Contents.
To assure successful installation and operation, the
user must study all instructions carefully before
starting to use the calorimeter to obtain an understanding of the capabilities of the equipment and the
safety precautions to be observed in the operation.
Note About Nomenclature:
Historically, burning a sample enclosed
in a high pressure oxygen environment is
known as Oxygen Bomb Calorimetry and
the vessel containing the sample is known
as an Oxygen Bomb. The terms bomb and
vessel are used interchangeably.
Note: The unit of heat used in this manual is
the International Table calorie, which is equal
to 4.1868 absolute joules.
Purpose
Heats of combustion, as determined in an oxygen
bomb calorimeter such as the 6200 Isoperibol
Calorimeter, are measured by a substitution procedure in which the heat obtained from the sample is
compared with the heat obtained from a standardizing material. In this test, a representative sample
is burned in a high-pressure oxygen atmosphere
within a metal pressure vessel or “bomb”. The
energy released by the combustion is absorbed
within the calorimeter and the resulting temperature
change is recorded.
Customer Service
Questions concerning the installation or operation of this instrument
can be answered by the Parr Customer Service Department:
1-309-762-7716 • 1-800-872-7720 • Fax: 1-309-762-9453
E-mail: parr@parrinst.com • http://www.parrinst.com
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Parr Instrument Company
6200
Explanation of Symbols
I On Position
O Off Position
~ Alternating Current
Preface
This CAUTION symbol may be present on the Product Instrumentation and literature. If present on the product, the user must consult
the appropriate part of the accompanying product literature for more
information.
ATTENTION, Electrostatic Discharge (ESD) hazards. Observe precautions for handling electrostatic sensitive devices.
Protective Earth (PE) terminal. Provided for connection of the protec-
tive earth (green or green/yellow) supply system conductor.
Chassis Ground. Identifies a connection to the chassis or frame of the
equipment shall be bonded to Protective Earth at the source of supply
in accordance with national and local electrical code requirements.
Earth Ground. Functional earth connection. This connection shall be
bonded to Protective earth at the source of supply in accordance with
national and local electrical code requirements.
Safety Information
To avoid electrical shock, always:
1. Use a properly grounded electrical outlet of
correct voltage and current handling capability.
2. Ensure that the equipment is connected to
electrical service according to local national
electrical codes. Failure to properly connect may
create a fire or shock hazard.
3. For continued protection against possible
hazard, replace fuses with same type and rating
of fuse.
4. Disconnect from the power supply before
maintenance or servicing.
To avoid personal injury:
1. Do not use in the presence of flammable or
combustible materials; fire or explosion may
result. This device contains components which
may ignite such material.
2. Refer servicing to qualified personnel.
Intended Usage
If the instrument is used in a manner not specified
by Parr Instrument Company, the protection provided by the equipment may be impaired.
General Specifications
Electrical Ratings
120VAC, 6.0 Amps. 50/60 Hz
240VAC, 3.0 Amps. 50/60 Hz
Before connecting the calorimeter to an electrical
outlet the user must be certain that the electrical
outlet has an earth ground connection and that the
line, load and other characteristics of the installation
do not exceed the following limits:
Voltage: Fluctuations in the line voltage should not
exceed 10% of the rated nominal voltage shown on
the data plate.
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Preface
Frequency: Calorimeters can be operated from
either a 50 or 60 Hertz power supply without affecting their operation or calibration.
Current: The total current drawn should not exceed
the rating shown on the data plate on the calorimeter by more than 10 percent.
Environmental Conditions
Operating: 15 ºC to 30 ºC; maximum relative humidity of 80% non-condensing. Installation Category II
(over voltage) in accordance with IEC 664. Pollution
degree 2 in accordance with IEC 664.
Altitude Limit: 2,000 meters.
Storage: -25 ºC and 65 ºC; 10% to 85% relative
humidity.
Provisions for Lifting and Carrying
Before moving the instrument, disconnect all connections from the rear of the apparatus. Lift the
instrument by grabbing underneath each corner.
Cleaning & Maintenance
Periodic cleaning may be performed on the exterior
surfaces of the instrument with a lightly dampened
cloth containing mild soap solution. All power
should be disconnected when cleaning the instrument. There are no user serviceable parts inside the
product other than what is specifically called out
and discussed in this manual. Advanced troubleshooting instructions beyond the scope of this
manual can be obtained by calling Parr Instrument
Company in order to determine which part(s) may
be replaced or serviced.
Getting Started
These steps are offered to help the user become
familiar with, install, operate and develop the full
capabilities of the Parr 6200 Calorimeter.
1. Review the Concept of Operations, Chapter 1, to
get an understanding of the overall capabilities
of the calorimeter and microprocessor control.
2. Unpack and install the calorimeter in accordance
with Installation, Chapter 2. This simple, stepwise procedure will acquaint the user with the
various parts of the calorimeter and make it
easier to understand the operating instructions
which follow.
3. Turn the power switch ON (located on the back).
Turn to the Instrument Description, Chapter 3, to
review the touch screen controls.
4. Review the Program Installation and Control,
Chapter 4, to match the factory settings to the intended mode of operation. Any required changes
can be made to the program parameters located
in the Main Menu.
5. Review the Reporting Instructions, Chapter 7, to
become familiar with the manner in which calorimetry corrections are entered. Also discussed
are generating final reports, editing and clearing
memory.
6. Turn to the Menu Operating Instructions, Ap-
pendix A, to review the menu functions used
to modify the program contained in the 6200
Calorimeter. A review of the menus will provide
a good idea of the capabilities and flexibility
designed into this instrument.
7. Review the Calculations, Appendix B. This pro-
vides information about calculations performed
by the 6200 Calorimeter.
8. Review Standardization, Appendix C. This will
serve two important functions. First, it provides
instructions on generating the energy equivalent
factor required to calculate the heat of combustion of unknown samples. Secondly, it will give
the user the opportunity to run tests on a material with a known heat of combustion to become
familiar with the instrument and confirm that the
instrument and operating procedures are producing results with acceptable precision. Most
6200 Calorimeters will have an energy equivalent of approximately 2400 calories per ºC. The
runs for standardization and determinations are
identical, except for the setting of the instrument
to the standardization or determination mode.
9. Review the Communication Interfaces, Appendix
D, for the correct installation of any peripherals
connected to the 6200 Calorimeter.
10. After successful standardization, the 6200 Calorimeter should be ready for testing samples.
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Concept of Operation
Overview
• The 6200 Calorimeter has been designed to
provide the user with:
Concept of Operation
The 1108P Oxygen Combustion Vessel is made of
high-strength, high nickel stainless steel designed
to resist the corrosive acids produced in routine fuel
testing. An alternative 1108PCL vessel is available,
constructed of an alloy containing additional cobalt
and molybdenum to resist the corrosive conditions
produced when burning samples containing chlorinated compounds.
1
• A traditional design calorimeter with removable
oxygen bomb and bucket.
• A moderately priced calorimeter which uses real
time temperature measurements to determine
heat leaks using a controlled calorimeter jacket.
• A high precision calorimeter capable of
exceeding the repeatability and reproducibility
requirements of all international standard test
methods.
• A compact calorimeter requiring minimum
laboratory bench space.
• A modern intuitive graphical user interface for
ease of operation and training.
• A calorimeter with up to date digital hardware,
software and communication capabilities.
• A calorimeter that is cost effective and which can
incorporate a user’s current bombs, buckets, and
accessories.
Removable Bomb
The Model 6200 Calorimeter utilizes the Parr 1108P
Oxygen Combustion Vessel. More than 20,000 of
these reliable 1108 style oxygen combustion vessels have been placed in service on a world wide
basis. This bomb features an automatic inlet check
valve and an adjustable needle valve for controlled
release of residual gasses following combustion.
They are intended for samples ranging from 0.6 to
1.2 grams with a maximum energy release of 8,000
calories per charge.
The Model 6200 can also be equipped with a variety
of special purpose oxygen combustion vessels for
unusual samples and/or applications. The 1104 High
Strength Oxygen Combustion Vessel is designed for
testing explosives and other potentially hazardous
materials. The 1109A Semimicro Oxygen Combustion Vessels can be fitted along with its unique
bucket to test samples ranging from 25 to 200 mg.
Removable Bucket
The A391DD removable bucket has been designed
to hold the bomb, stirrer and thermistor with a minimum volume of water and to provide an effective
circulating system which will bring the calorimeter
to rapid thermal equilibrium both before and after
firing.
Dynamic Operation
In its Dynamic Operating Mode, the calorimeter
uses a sophisticated curve matching technique to
compare the temperature rise with a known thermal curve to extrapolate the final temperature rise
without actually waiting for it to develop. Repeated
testing, and over 20 years of routine use in fuel
laboratories, has demonstrated that this technique
can cut the time required for a test by one-half
without significantly affecting the precision of the
calorimeter.
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1
Concept of Operation
Full Microprocessor Based Process Control
The microprocessor controller in this calorimeter
has been pre-programmed to automatically prompt
the user for all required data and control input and
to:
• Generate all temperature readings in the
calorimeter.
• Monitor jacket as well as bucket temperature.
• Confirm equilibrium conditions.
• Fire the bomb.
• Confirm that ignition has occurred.
• Determine and apply all necessary heat leak
corrections.
• Perform all curve matching and extrapolations
required for dynamic operation.
• Terminate the test when it is complete.
• Monitor the conditions within the calorimeter
and report to the user whenever a sensor or
operating condition is out of normal ranges.
Full Microprocessor Based Data Acquisition and Handling
In addition to its process control functions, the
microprocessor in the calorimeter has been preprogrammed to:
• Collect and store all required test data.
• Apply all required corrections for combustion
characteristics.
Flexible Programming
The fifth generation software built into this calorimeter and accessed through the screen menus permit
the user to customize the operation of the calorimeter to meet a wide variety of operating conditions
including:
• A large selection of printing options.
• Choice of accessories and peripheral equipment.
• Multiple options in regard to handling
thermochemical corrections.
• Choice of ASTM or ISO correction procedures.
• A variety of memory management and reporting
procedures.
• Complete freedom for reagent concentrations
and calculations.
• Unlimited choice of reporting units.
• Automatic bomb usage monitoring and
reporting.
• A choice of Equilibrium or Dynamic test
methods.
• Automatic statistical treatment of calibration
runs.
• Enhanced testing and trouble shooting
procedure.
The 6200 Calorimeter is equipped with one USB
connection for direct communication with its printer
and other peripherals. It is also equipped with an
Ethernet network connection for connections to
laboratory computers.
• Compute and report the heat of combustion for
the sample.
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Installation
Note: Some of the following manual sections contain information in the form of
warnings, cautions and notes that require
special attention. Read and follow these
instructions carefully to avoid personal injury
and damage to the instrument. Only qualified personnel should conduct the installation tasks described in this portion of the
manual.
Environmental Conditions
The 6200 Calorimeter is completely assembled and
given a thorough test before it is shipped from the
factory. If the user follows these instructions, installation of the calorimeter should be completed with
little or no difficulty. If the factory settings are not
disturbed, only minor adjustments will be needed to
adapt the calorimeter to operating conditions in the
user’s laboratory.
This apparatus is to be used indoors. It requires
at least 8 square feet of workspace on a sturdy
bench or table in a well-ventilated area with convenient access to an electric outlet, running water
and a drain. The supply voltage must be within ±
10% of marked nominal voltage on the apparatus.
The supply voltage receptacle must have an earth
ground connection.
Required Consumables, Utilities and Power Requirements
The 6200 Calorimeter System requires availability of
Oxygen, 99.5% purity, 2500 psig maximum.
The power requirements for the subassemblies of
the 6200 Calorimeter are:
Calorimeter
120VAC, 6.0 Amps. 50/60 Hz
240VAC, 3.0 Amps. 50/60 Hz
Installation
Filling the Jacket Reservoir
The water reservoir of the calorimeter must be filled
with approximately 1.4 liters of water (distilled or
de-ionized preferred). This must be done prior to
turning on the heater and the pump. The reservoir is
filled through the tank fill elbow on the back of the
calorimeter. The tank is full once water stands in the
horizontal run of the filling elbow.
Power Connection
Plug the power line into any grounded outlet providing proper voltage that matches the specification
on the nameplate of the calorimeter. The calorimeter will draw approximately 300 watts of power.
Grounding is very important not only as a safety
measure, but also to ensure satisfactory controller
performance. If there is any question about the
reliability of the ground connection through the
power cord, run a separate earth ground wire to the
controller chassis.
Turn the power switch to the on position. After a
short time, the Parr logo will appear on the LCD
display followed by a running description of the
instrument boot sequence. When the boot sequence
is complete, the calorimeter Main Menu is displayed. Go to the Calorimeter Operation page and
turn the heater and pump on. This begins circulating
and heating the calorimeter jacket water. Add water
to the filling elbow at the rear of the instrument as
required in order to keep it full.
Jacket Cooling Water Connection
It becomes necessary to use the jacket cooling water
connection only if the calorimeter operating room
temperature exceeds 24 °C (75 °F).
When required, an external water source is used to
cool the jacket of the 6200 Calorimeter. This is done
in either of the following ways:
1. Tap water is used for cooling and then run to a
drain.
2. Cooling water is re-circulated to the calorimeter
from a Parr 6510 Water Handling System.
2
Printer
100 to 240 VAC, 0.35 Amps 50/60 Hz
Printer Supplies
334C Printer Paper
335C Printer Ribbon
The water that provides the cooling goes through a
heat exchanger and does not mix with the water in
the jacket and its reservoir. There is a very low cooling load and tap water up to a temperature of 27 °C
should be adequate.
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2
Installation
Tap Water Cooling
Connect the tap water supply to the cold water inlet
on the back of the calorimeter using either 1/4”
copper or nylon tubing (HJ0025TB035). A 196VB
metering valve is provided with the calorimeter.
This valve should be installed in this inlet line near
the calorimeter. This valve is used to adjust the flow
of water to the heat exchanger to compensate for
differences in tap water temperatures and water line
pressures. Once the calorimeter is operating at equilibrium, check the jacket temperature that is displayed
on the operating page. If this temperature is cycling
significantly, close down on the metering valve to
reduce the flow of cooling water. If the jacket rises
above its 30 °C set point, open this valve to increase
the cooling. A ow rate of 100 ml/ minute is generally
all that is required.
Connect the cooling water outlet on the back
of the calorimeter to a drain using either nylon
(HJ0025TB035) or copper 1/4” tubing. A shut off
valve in tap water supply line is also a good idea
if the calorimeter will not be used for an extended
period.
Cooling with the Water Handling System
If the calorimeter is to be operated with a Parr Water
Handling System, connect the pump output to the
cooling water inlet and connect the cooling water
outlet to the return connection on the water handling
system. With this installation it is neither necessary
nor desirable to install the 196VB metering valve in
the inlet line. It is a good idea to keep all water line
runs as short as practical to avoid unwanted temperature changes in the water between the source and the
calorimeter.
Oxygen Filling Connection
The 6200 Calorimeter is equipped with an automatic
bomb oxygen filling system. This system consists of
an oxygen pressure regulator with a relief valve that
mounts on an oxygen tank and a controlled solenoid
inside the calorimeter. To install the regulator on the
oxygen supply tank, unscrew the protecting cap from
the oxygen tank and inspect the threads on the tank
outlet to be sure they are clean and in good condition. Place the ball end of the regulator in the outlet
and draw up the union nut tightly, keeping the gages
tilted slightly back from an upright position. Connect
the regulator to the oxygen inlet fitting on the back of
the calorimeter case. This hose should be routed so
that it will not kink or come in contact with any hot
surface. Connect the high-pressure nylon hose with
the push on connector to the oxygen outlet fitting on
the back of the calorimeter.
All connections should be checked for leaks. Any
leaks detected must be corrected before proceeding.
Instructions for operating the filling connection are in
the Operating Instructions chapter.
Adjust the pressure regulator to deliver 450 psi of O2.
Assemble the oxygen bomb without a charge and
attach the filling hose to the bomb inlet valve. Press
the O2 Fill key on the Calorimeter Operation page and
observe the delivery pressure on the 0 – 600 psi gage
while the oxygen is flowing into the bomb. Adjust the
regulator, if needed, to bring the pressure to 450 psi.
If there is any doubt about the setting, release the gas
from the bomb and run a second check.
Printer and Balance Connections
Connect the printer to the calorimeter at this time.
The Parr 1758 Printer is configured and furnished with
a cord to connect directly to the USB port on the back
of the calorimeter.
If a balance is to be attached to the calorimeter it
will be necessary to use a USB hub so that multiple
devices can be connected. Any standard USB hub can
be used.
Standardizing the Calorimeter
The calorimeter must be accurately standardized prior
to actually performing calorimetric tests on sample
materials. Review Appendix C - Standardization, in
order to become familiar with the general procedure
and calculations. The user should configure the
calorimeter at this time to accommodate the desired
sample weight entry mode. The calorimeter can be
placed into standardization mode on the Calorimeter
Operation Page, with the OPERATING MODE key.
If two bombs and buckets are being used with the
calorimeter to maximize sample throughput, the
calorimeter can be configured to prompt for a Bomb
ID at the start of each test. The Bomb ID can also be
selected on the Calorimeter Operations Page, using
the Bomb/EE key. All bomb and bucket combinations
will need to be standardized separately. The end result
of a standardization test is an energy equivalent
value, or the amount of energy required to raise the
temperature of the calorimeter one degree. Repeated
standardization with any given bomb and bucket
combination should yield an energy equivalent value
with a range of 14 calories per degree, centered
around the mean value for all tests using that bomb
and bucket combination. The calorimeter is ready for
testing samples after an energy equivalent value has
been obtained.
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Installation
2
Swagelok Tube Fittings
When Swagelok Tube Fittings are used, the instructions for installation are:
1. Simply insert the tubing into the Swagelok Tube
Fitting. Make sure that the tubing rests firmly
on the shoulder of the fitting and that the nut is
finger-tight.
2. Before tightening the Swagelok nut, scribe the
nut at the 6 o’clock position.
3. While holding the fitting body steady with a
back-up wrench, tighten the nut 1-1/4 turns.
Watch the scribe mark, make one complete
revolution and continue to the 9 o’clock position.
4. For 3/16” and 4mm or smaller tube ttings,
tighten the Swagelok nut 3/4 turns from nger-
tight.
Swagelok tubing connections can be disconnected
and retightened many times. The same reliable leakproof seal can be obtained every time the connection is remade using the simple two-step procedure.
Figure 2-1
Swagelok Tube Fittings
1. Insert the tubing with pre-swaged ferrules into
the fitting body until the front ferrule seats.
2. Tighten the nut by hand. Rotate the nut to the
original position with a wrench. An increase in
resistance will be encountered at the original
position. Then tighten slightly with a wrench.
Smaller tube sizes (up to 3/16” or 4mm) take less
tightening to reach the original position than
larger tube sizes.
The type of tubing and the wall thickness also has
an effect on the amount of tightening required.
Plastic tubing requires a minimal amount of additional tightening while heavy wall metal tubing
may require somewhat more tightening. In general,
the nut only needs to be tightened about 1/8 turn
beyond finger tight where the ferrule seats in order
to obtain a tight seal.
Over tightening the nut should be avoided. Over
tightening the nut causes distortion (flaring) of the
lip of the tube fitting where the ferrule seats. This
in turn causes the threaded portion of the body to
deform. It becomes difficult to tighten the nut by
hand during a subsequent re-tightening when the
fitting body becomes distorted in this manner.
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2
Installation
Figure 2-2
6200 Calorimeter Back Panel
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6200
Line 3
Figure 2-3
Closed Loop Configuration with 6510
O2 Regulator
Line 2
6510 Water
Handling
System
Installation
2
Line 3
Line 1
~27 °C
Figure 2-4
Open Loop Configuration with Tap Water
O2 Regulator
Tap Water
· <27 °C
Line 2
Line 1
Drain
Line 1 & 2 – Maximum length of 10 feet, 1/4” OD, Polyurethane (Part Number HJ0025TB035)
Line 3 – Maximum length of 25 feet, 1/8” OD, Nylon (Part Number HX0012TB024)
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2
Installation
Figure 2-5
Open Loop Configuration with 1552
O2 Regulator
Tap Water
· >27 °C
Line 3
Line 2
Line 1
~27 °C
Line 1 & 2 – Maximum length of 10 feet, 1/4” OD, Polyurethane (Part Number HJ0025TB035)
Line 3 – Maximum length of 25 feet, 1/8” OD, Nylon (Part Number HX0012TB024)
Water
Cooler
Drain
1552
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Instrument Description
Types of Controls
All calorimeter configurations and operations are
handled by a menu-driven system operated from
the bright touch screen display. The settings and
controls are organized into nine main sections or
pages which comprise the MAIN MENU.
Instrument Description
pad or similar screen for entering the required
value. Some keys lead to multiple choices.
Always clear the current value before entering a
new value. Once entered the screen will revert
to the previous menu and the new value will be
displayed in the lower right corner of the key.
4. Data Displays. Most of these keys display values
that have been calculated by the calorimeter
and are informational only. Certain ones can be
overridden by the user entering a desired value
through a sub-menu. The value is displayed in
the lower right corner of the key.
3
Note: Keys with a “double box” in the upper
left hand corner lead to sub-menus.
Menu Keys
The controls that change the data field information
in the menus will be one of the following:
1. Toggles. These data elds contain ON/OFF or
YES/NO choices. Simply touching the key on the
screen toggles the choice to the other option.
The current setting is displayed in the lower
right corner of the key.
2. Option Selection. These data fields contain a list
of options. Touching the key on the screen steps
the user through the available choices. The
current setting is displayed in the lower right
corner of the key.
Note: Some keys will respond with an opportunity for the user to confirm the specified action to minimize accidental disruptions to the program and/or stored data.
Control Keys
There are five control keys which always appear in
the right column of the primary displays. These keys
are unavailable when they are gray instead of white.
1. Escape. This key is used to go up one level in
the menu structure.
2. Main Menu. This key is used to return to the
main menu touch screen from anywhere in the
menu structure.
3. Start. This key is used to start a calorimeter test.
4. Report. This key is used to access the test
results stored in the calorimeter, to enter
thermochemical corrections and to initiate
report on the display, printer or attached
computer.
5. Help. This key is used to access help screens
related to the menu currently displayed on the
touch screen.
6. Abort. This key appears in the start key location
while the test is running. Pressing this key will
abort the test in progress.
3. Value Entry Fields. These data fields are used to
enter data into the calorimeter. Touching the key
on the screen brings up a sub menu with a key
7. This key appears on the main menu only and
is used to prepare the calorimeter for turning off
the power.
www.parrinst.com
15
Notes
16
Parr Instrument Company
6200
chaPter 4
Program Installation & Control
Software Installation
Program Installation & Control
Revising Default Settings
The default parameters of the 6200 Calorimeter can
be changed to guarantee that the 6200 Calorimeter,
when cold restarted, will always be in the desired
configuration before beginning a series of tests.
4
The program in the 6200 Calorimeter can be extensively modified to tailor the unit to a wide variety
of operating conditions, reporting units, laboratory
techniques, available accessories and communication modes.
In addition, the calculations, thermochemical corrections, and reporting modes can be modified to
conform to a number of standard test methods and
procedures.
Numerous provisions are included to permit the
use of other reagent concentrations, techniques,
combustion aids and short cuts appropriate for the
user’s work.
Note: Changes to the program are made by
use of the menu structure described in Appendix A of this manual. Any of these items
can be individually entered at any time to
revise the operating program.
Default Settings
Users who wish to permanently revise their default
settings may do so using the following procedure:
• Establish the operating parameters to be stored
as the user default settings.
• Go to the Program Info and Control Menu, User/
Factory Settings, User Setup ID, and enter the
desired User Setup ID.
• Select Save User Default Settings
To re-load the user default settings, go to the Pro-
gram Info and Control Page, User/Factory Settings,
Re-load User Default Settings, and YES.
Units are pre-programmed with default settings. See
pages 17 and 18 for a listing of the factory default
settings.
These default settings remain in effect until changed
by the user. Should the user ever wish to return
to the factory default settings, go to the Program
Information and Control Menu, then to User/Factory
Settings, and then touch Reload Factory Default
Settings and YES.
Non-volatile memory is provided to retain any and
all operator initiated program changes; even if
power is interrupted or the unit is turned off. If the
unit experiences an intentional or unintentional
“Cold Restart”, the controller will return to its default
settings.
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17
4
Program Installation & Control
6200 Factory Default Settings
Calorimeter Operations
Operating Mode Determination
Bomb Installed/EE 1/2400.0
Heater and Pump OFF
Operating Controls
Method of Operation Dynamic
Reporting Units BTU/lb
Use Spiking Correction OFF
“OTHER” Multiplier 4.1868
Calibrate Touchscreen
LCD Backlight Timeout(s)
LCD Backlight Intensity 70%
Print Error Messages ON
Language English
1200 S
Table 4-1
Calibration Data & Controls
Calibration Run Limit
EE Max Std Deviation 0.0
Heat of Combustion of Standard 6318.4
Bomb Service Interval 500
Control Chart Parameters
Charted Value HOC Standard
Process Sigma 0.1
Temp Rise High Warning 3.3
Temp Rise Low Warning 2.0
Use Bomb 1
10
Bomb 1 Through 4
EE Value 2400.0
Protected EE Value OFF
Spike Controls
Use Spiking OFF
Heat of Combustion of Spike 6318.4
Use Fixed Spike OFF
Weight of Fixed Spike 0.0
Prompt for Spike before Weight OFF
Program Information and Control
Date & Time Settings
Volume Level Adjust 85%
Software and Hardware Info
Settings Protect OFF
User/Factory Settings
Feature Key
Bomb Type Select
User Function Setup
Cold Restart
User/Factory Settings
User Setup ID 62-1108
Reload Factory Default Settings
Reload User Default Settings
Save User Default Settings
Thermochemical Corrections Standardization
Fixed Fuse Correction ON 50
Acid Correction Fixed HNO3 10.0
Fixed Sulfur Correction ON 0.0
Determination
Fixed Fuse Correction ON 50
Acid Correction Fixed HNO3 10.0
Fixed Sulfur Correction OFF 0.0
Net Heat/Dry Factors Net Heat & Dry Disable
Fixed Hydrogen
Fixed Oxygen ON 0.0
Fixed Nitrogen ON 0.0
Calculate Net Heat of Combustion OFF
Fixed Moisture as Determined OFF 0.0
Fixed Moisture as Received OFF 0.0
Dry Calculation OFF
OFF 0.0
18
Parr Instrument Company
6200
Table 4-1 (Continued)
6200 Factory Default Settings
Calculation Factors
Nitric Acid Factor 1.58
Acid Multiplier 0.0709
Sulfur Value is Percent ON
Sulfur Multiplier 0.6238
Fuse Multiplier 1. 0
Use Offset Correction (ISO) OFF
Offset Value 0.0
Data Entry Controls
Prompt for Bomb ID ON
Weight Entry Modes Touch Screen
Acid Entry Mode Touch Screen
Net Heat Entry Modes Touch Screen
Auto Sample ID Controls ON
Sample Weight Warning above 2.0
Spike Weight Entry Mode Touch Screen
Sulfur Entry Mode Touch Screen
Moisture Entry Mode Touch Screen
Auto Preweigh Controls ON
Auto Sample ID Controls
Automatic Sample ID ON
Automatic Sample ID Increment 1
Automatic Sample ID Number 1
Auto Preweigh Controls
Automatic Preweigh ID ON
Automatic Preweigh ID Increment 1
Automatic Preweigh ID Number 1
Program Installation & Control
Communication Controls
Printer Type Parr 1758
Balance Port
Network Interface
Printer Destination Local (USB)
Bar Code Port
Network Data Devices
Balance Port Communications
Balance Type
Balance Port Device
Customize Balance Settings
Balance Port Settings
Number of Data Bits 8
Parity None
Number of Stop Bits 1
Handshaking None
Baud Rate 9600
Data Characters from Balance 8
Data Precision 4
Transfer Timeout (seconds) 10
Balance Handler Strings
Data Logger
Data Logger OFF
Data Log Interval 12s
Data Log Destination Log File and Printer
Select Data Log Items
Data Log Format Text Format
Generic
4
Reporting Controls
Report Width 40
Automatic Reporting ON
Auto Report Destination Printer
Individual Printed Reports OFF
Edit Final Reports OFF
Recalculate Final Reports OFF
Use New EE Values in Recalculation OFF
www.parrinst.com
19
Notes
20
Parr Instrument Company
6200
Operating Instructions
chaPter 5
Operating Instructions
Operating the Calorimeter
All operations required to standardize the 6200
Calorimeter, or test an unknown sample, should
proceed step-wise in the following manner:
5
Operating the 1108P Oxygen Combustion Vessel
Detailed instructions for preparing the sample and
charging the 1108P Oxygen Combustion Vessels are
given in Operating Instructions No. 418M. Follow
these instructions carefully, giving particular attention to the precautions to be observed in charging
and handling the bomb.
Operating the Filling Connection
To fill the bomb, connect the hose to the bomb inlet
valve and push the O2 Fill button on the calorimeter
control panel. The calorimeter will then fill the bomb
to the preset pressure and release the residual
pressure in the connecting hose at the end of the
filling cycle. It will take approximately 60 seconds to
fill the bomb. During this time a countdown timer
on the O2 fill button will display the remaining fill
time. Pushing the O2 key a second time will stop the
flow of oxygen at any time. Once the display returns
to its normal reading, the user can disconnect the
coupling and proceed with the combustion test.
If the charging cycle should be started inadvertently,
it can be stopped immediately by pushing the O2
FILL key a second time.
During extended periods of inactivity, overnight
or longer, close the tank valve to prevent leakage.
When changing oxygen tanks, close the tank valve
and push the O2 FILL key to exhaust the system. Do
not use oil or combustible lubricants on this filling
system or on any devices handling oxygen under
pressure. Keep all threads, fittings, and gaskets clean
and in good condition. Replace the two 394HCJE
O-rings in the slip connector if the connector fails to
maintain a tight seal on the bomb inlet valve.
The recommended filling pressure is 450 psig (3
MPa or 30 bar). This pressure is prescribed by most
of the standard bomb calorimetric test methods.
Higher or lower filling pressures can be used, but
the bomb must never be filled to more than 600
psig (40 atm).
1. Turn on the calorimeter and activate the pump
and heater using Calorimeter Operations. Allow
at least 20 minutes for the calorimeter to warm
up and the jacket temperature to stabilize. Once
the jacket temperature comes within 0.5 °C of 30
°C and stays there for approximately 15 minutes, the calorimeter is ready to begin testing.
The Start key will be available at this time. The
bomb parts should be wetted and then dried in
the manner used at the conclusion of a test. This
serves to wet all sealing parts as well as leaving the bomb with the same amount of residual
water which will exist in all subsequent testing.
2. Prepare the sample weighing the material to 0.1
mg and charge the oxygen bomb as described in
the section entitled Operating the Filling Con-
nection. Using an additional bomb and bucket
can increase the throughput of the 6200 Calorimeter. With this arrangement, the calorimeter can
operate almost continuously since the operator
will be able to empty a bomb and recharge it
while a run is in progress. A bomb and bucket
for the next run will be ready to go into the calorimeter as soon as it is opened. Each bomb and
bucket combination will have to be standardized
separately and the proper energy equivalent for
each set must be used when calculating the heat
of combustion.
3. Fill the calorimeter bucket by first taring the dry
bucket on a solution or trip balance; then add
2000 (+/- 0.5) grams of water. Distilled water is
preferred, but demineralized or tap water containing less than 250 ppm of dissolved solids
is satisfactory. The bucket water temperature
should be approximately 3 to 5 °C below the
jacket temperature. It is not necessary to use
exactly 2000 grams, but the amount selected
must be duplicated within +/- 0.5 gram for each
run. Instead of weighing the bucket, it can be
filled from an automatic pipet, or from any other
volumetric device if the repeatability of the filling
system is within +/- 0.5 ml.
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21
5
Operating Instructions
To speed and simplify the bucket filling process,
and to conserve water and energy, Parr offers
a closed circuit Water Handling System (No.
6510). This provides a water supply, cooled
to the starting temperature and held in an
automatic pipet ready for delivery in the exact
amount needed to fill the bucket. Instructions
for this automatic system are given in Operating
Instruction No. 454M.
4. Set the bucket in the calorimeter. Attach the
lifting handle (421A) to the two holes in the
side of the screw cap and partially lower the
bomb into the water. Handle the bomb carefully
during this operation so that the sample will not
be disturbed. Push the two ignition lead wires
into the terminal sockets on the bomb head.
Orient the wires away from the stirrer shaft
so they do not become tangled in the stirring
mechanism. Lower the bomb completely into
water with its feet spanning the circular boss
in the bottom of the bucket. Remove the lifting
handle and shake any drops of water back into
the bucket and check for gas bubbles.
Note: If bubbles continue to rise from the
bomb after the air in the screw cap has
escaped the test must be stopped and the
bomb not fired until the leak has been corrected.
5. Close the calorimeter cover. This lowers the
stirrer and thermistor probe into the bucket.
Make sure that the bucket thermistor does
not touch the bucket or 1108P when the lid is
lowered.
6. Select determination or standardization as
appropriate on the Calorimeter Operation menu
by toggling the OPERATING MODE key. After
pressing the STA RT key, the calorimeter will
now prompt the operator for Bomb ID number,
sample ID number, sample weight and spike
weight in accordance with the instructions set
into the operating controls page.
the status bar. Just before it fires the bomb, it
will sound a series of short beeps to warn the
user to move away from the calorimeter. Once
the bomb has been fired, the status bar will
display POSTPERIOD. The calorimeter will check
to make certain that a temperature rise occurs
and will then look for the final equilibrium
conditions to be met. If it fails to meet either the
initial or final equilibrium conditions, or if it fails
to detect a temperature rise within the allotted
time, the calorimeter will terminate the test and
advise the user of the error.
8. At the conclusion of the test, the calorimeter will
signal the user.
9. Open the cover and remove the bomb and
bucket. Remove the bomb from the bucket
and open the knurled valve knob on the bomb
head to release the residual gas pressure before
attempting to remove the cap. This release
should proceed slowly over a period of not less
than one minute to avoid entrainment losses.
After all pressure has been released, unscrew
the cap, lift the head out of the cylinder and
examine the interior of the bomb for soot or
other evidence of incomplete combustion. If
such evidence is found, the test will have to be
discarded. Otherwise, wash all interior surfaces
of the bomb, including the head, with a jet of
distilled water and collect the washings in a
beaker.
10. Titrate the bomb washings with a standard
sodium carbonate solution using methyl orange,
red or purple indicator. A 0.0709N sodium
carbonate solution is recommended for this
titration to simplify the calculation. This is
prepared by dissolving 3.76 grams of Na2CO3 in
the water and diluting to one liter. NaOH or KOH
solutions of the same normality may be used.
11. Analyze the bomb washings to determine the
sulfur content of the sample if it exceeds 0.1%.
Methods for determining sulfur are discussed in
Operating Instructions No. 207M.
7. The calorimeter will now take over and conduct
the test. During the time it is establishing the
initial equilibrium, it will display PREPERIOD on
22
Parr Instrument Company
12. At the end of the testing period, turn OFF the
calorimeter at the power switch.
6200
Operating Instructions
5
Samples and Sample Holders
Particle Size and Moisture Content. Solid samples
burn best in an oxygen bomb when reduced to 60
mesh, or smaller, and compressed into a pellet with
a 2811 Parr Pellet Press.
Large particles may not burn completely and small
particles are easily swept out of the capsule by
turbulent gases during rapid combustion.
Note: Particle size is important because it influences the reaction rate. Compression into
a pellet is recommended because the pressure developed during combustion can be
reduced as much as 40% when compared to
the combustion of the material in the powder
form. In addition in giving controlled burn
rates, the pelletizing of samples keeps the
sample in the fuel capsule during combustion.
Materials, such as coal, burn well in the as-received
or air-dry condition, but do not burn completely dry
samples. A certain amount of moisture is desirable
in order to control the burning rate. Moisture content up to 20% can be tolerated in many cases, but
the optimum moisture is best determined by trial
combustions.
If moisture is to be added to retard the combustion
rate, drop water directly into a loose sample or onto
a pellet after the sample has been weighed. Then
let the sample stand for awhile to obtain uniform
distribution.
Also, when benzoic acid is combusted for standardization runs or for combustion aid purposes, it
should be in the form of a pellet to avoid possible
damage to the bomb which might result from rapid
combustion of the loose powder.
Oxygen Charging Pressure
The 6200 Calorimeter has been designed to operate
with an oxygen filling pressure of 30 atm. Significant changes from this value are not recommended.
Combustion Capsules
Non-volatile samples to be tested in Parr oxygen
bombs are weighed and burned in shallow capsules
measuring approximately 1” diameter and 7/16”
deep. These are available in stainless steel, fused
silica, fused quartz, and platinum alloyed with
3-1/2% rhodium.
Stainless steel capsules 43AS are furnished with
each calorimeter. When combusting samples that
contain metal particles such as aluminum or magnesium, the non-metallic fused silica 43A3 capsule
or fused quartz 43A3KQ capsule is required. When
superior corrosion resistance is needed, the platinum rhodium 43A5 capsule is required.
The stainless steel capsules will acquire a dull gray
finish after repeated use in an oxygen bomb due to
the formation of a hard, protective oxide film. This
dull finish not only protects the capsule, but it also
promotes combustion and makes it easier to burn
the last traces of the sample.
Combustion Aids
Some samples may be difficult to ignite or they may
burn so slowly that the particles become chilled
below the ignition point before complete combustion is obtained. In such cases benzoic acid, white oil
or any other combustible material of known purity
can be mixed with the sample. Ethylene glycol,
butyl alcohol or decalin may also be used for this
purpose.
Note: It must be remembered, however, that
a combustion aid adds to the total energy
released in the bomb and the amount of
sample may have to be reduced to compensate for the added charge.
Capsules should be monitored for wear. Do not use
the capsule if the wall or base thickness is less than
0.025”.
New capsules are heated in a muffle furnace at
500 ºC for 24 hours by Parr to develop this protective coating uniformly on all surfaces. This treatment
should be repeated after a capsule has been polished with an abrasive to remove any ash or other
surface deposits. Heating in a muffle is also a good
way to destroy any traces of carbon or combustible
matter which might remain in the capsule from a
previous test.
Note: After heating, place the capsules in
a clean container and handle them only
with forceps when they are removed to be
weighed on an analytical balance.
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23
5
Operating Instructions
Foodstuffs and Cellulosic Materials
Fibrous and fluffy materials generally require one
of three modes of controlling the burn rate. Fibrous
materials do not pelletize readily and generally
require either moisture content or a combustion aid
such as mineral oil to retard the burn rate and avoid
development of high pressures.
Partial drying may be necessary if the moisture content is too high to obtain ignition, but if the sample
is heat sensitive and cannot be dried, a water
soluble combustion aid such as ethylene glycol can
be added to promote ignition.
Coarse Samples
In most cases it may be necessary to burn coarse
samples without size reduction since grinding or
drying may introduce unwanted changes. There
is no objection to this if the coarse sample will
ignite and burn completely. Whole wheat grains
and coarse charcoal chunks are typical of materials
which will burn satisfactorily without grinding and
without additives or a special procedure.
Corrosive Samples
The 1108P Oxygen Combustion Vessel is made of a
corrosion resistant alloy designed to withstand the
corrosive mixture of sulfuric and nitric acids produced in normal fuel testing operations. Samples
containing chlorine and particular samples containing more than 20 mg of chlorine samples with high
sulfur contents will greatly accelerate corrosion of
the bomb. An alternate 1108PCL is available constructed of an alloy selected to specifically resist the
corrosive effects of samples with high chlorine or
chloride.
While no material will offer complete corrosion
resistance to these samples, the 1108PCL offers
significantly enhanced corrosion resistance for this
service.
Explosives and High Energy Fuels
The 1108P and 1108PCL used in the 6200 Calorimeter
have been designed to provide highly automated
testing of routine samples. Materials which release
large volumes of gas which detonate with explosive
force or burn with unusually high energy levels
should not be tested with these bombs. Rather,
they should be tested in a model 1104 High Pressure
Oxygen Combustion Vessel designed specifically for
these types of samples.
Volatile Sample Holders
Volatile samples can be handled in a Parr 43A6
platinum capsule with a spun rim, or in a Parr 43AS
stainless steel capsule which has a sturdy wall with
a flat top rim. These holders can be sealed with a
disc of plastic adhesive tape prepared by stretching
tape across the top of the cup and trimming the
excess with a sharp knife. The seal obtained after
pressing this disc firmly against the rim of the cup
with a flat blade will be adequate for most volatile
samples.
The tape used for this purpose should be free of
chlorine and as low in sulfur as possible. Borden
Mystic Tape, No. M-169-C or 3M Transparent Tape,
No. 610, are recommended for this purpose. The 3M
Transparent Tape can be ordered through Parr, Part
No. 517A.
The weight of the tape disc must be determined
separately and a correction applied for any elements
in the tape which might interfere with the determination. The approximate Heat of Combustion of
the tape is 6300 cal/g. An actual amount should be
determined by running a blank test with tape alone
using a sample weighing 1.0 gram. The compensation for heat of tape may be done through the spike
option; see Spike Controls, Line 2 - Heat of Combustion of Spike.
Note: Tape should always be stored in a
sealed container to minimize changes in its
moisture and solvent content.
24
Parr Instrument Company
6200
Operating Instructions
5
Figure 5-7
Combustion Capsule with Adhesive Tape Seal
Use the following procedure when filling and handling any of these tape-sealed sample holders:
• Weigh the empty cup or capsule; then cover the
top with tape, trim with a knife and press the
trimmed edge firmly against the metal rim. Also
cut and attach a small flag to the disc (see Figure
5-7).
• Puncture the tape at a point below the flag, then
re-weigh the empty cup with its tape cover.
• Add the sample with a hypodermic syringe;
close the opening with the flag and re-weigh the
filled cup.
• Set the cup in the capsule holder and arrange
the auxiliary fuse so that it touches the center of
the tape disc.
• Just before starting the test, prick the disc with
a sharp needle to make a small opening which
is needed to prevent collapse of the disc when
pressure is applied.
• Fill the bomb with the usual oxygen charging
pressure.
• The calorimeter will fire the bomb and complete
the test in the usual manner.
Poor Combustion
Because of the difference in combustion characteristics of the many different materials which
may be burned in an oxygen bomb, it is difficult to
give specific directions which will assure complete
combustions for all samples.
The following fundamental conditions should be
considered when burning samples:
• Some part of the sample must be heated to its
ignition temperature to start the combustion
and, in burning, it must liberate sufficient heat
to support its own combustion regardless of the
chilling effect of the adjacent metal parts.
• The combustion must produce sufficient turbulence within the bomb to bring oxygen into
the fuel cup for burning the last traces of the
sample.
• Loose or powdery condition of the sample which
will permit unburned particles to be ejected during a violent combustion.
• The use of a sample containing coarse particles
which will not burn readily. Coal particles which
are too large to pass a 60 mesh screen may not
burn completely.
• The use of a sample pellet which has been made
too hard or too soft. Either condition can cause
spalling and the ejection of unburned fragments.
• Insufficient space between the combustion cup
and the bottom of the bomb. The bottom of the
cup should always be at least one-half inch above
the bottom of the bomb or above the liquid level
in the bomb to prevent thermal quenching.
• Excessive moisture or non-combustible material
in the sample. If the moisture, ash and other non
combustible material in the sample amounts to
approximately 20% or more of the charge, it may
be difficult to obtain complete combustion. This
condition can be remedied by adding a small
amount of benzoic acid or other combustion aid.
Volatile samples are defined as one with an initial
boiling point below 180 °C per ASTM D-2.
Low volatile samples with a high water content, such
as urine or blood, can be burned in an open capsule
by absorbing the liquid on filter paper pulp or by
adding a combustion aid, such as ethylene glycol.
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25
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