Hart Scientific 9115 User manual

9115 Furnace
User Manual
Rev. 761301
HART
SCIENTIFIC

© Copyright,1997 All Rights Reserved
Hart Scientific
799 E. Utah Valley Drive
American Fork, Utah 84003-9775
Telephone: [phone] • Fax: [phone]
Internet: http://www.hartscientific.com

WARNING
To ensure the safety of operating personnel, and to avoid damage to this equipment:
DO NOT operate this unit without a properly grounded, properly polarized power cord.
DO NOT connect this unit to a non-grounded, non-polarized outlet.
DO USE a ground fault interrupt device.
WARNING
HIGH VOLTAGE
is used in the operation of this equipment.
SEVERE INJURY OR DEATH
may result if personnel fail to observe safety precautions.
Before working inside the equipment, turn power off and disconnect power cord.
WARNING
This unit contains ceramic fiber or other refractories, which can result in the following:
May be irritating to skin, eyes, and respiratory tract.
May be harmful if inhaled.
May contain or form cristobalite (crystalline silica) with use at high temperatures (above 1600°F) which can
cause severe respiratory disease.
Possible cancer hazard based on tests with laboratory animals. Animal studies to date are inconclusive.No
human exposure studies with this product have been reported.
Service personnel coming into contact with these materials should take proper precautions when handling
them. Before maintaining this equipment, read the applicable MSDS (Material Safety Data Sheets).
c

WARNING
HIGH TEMPERATURES PRESENT
in this equipment
FIRES AND SEVERE BURNS
may result if personnel fail to observe safety precautions.
WARNING
To ensure the safety of personnel, and to avoid damage to equipment:
DO NOT use this unit for any application other than calibration work.
DO NOT use this unit in environments other than those listed in the user's manual.
Continuous use of this equipment at high temperatures for extended periods of time
requires caution.
Completely unattended high temperature operation is not recommended for
safety reasons.
Components and heater lifetimes can be shortened by continuous high temperature operation.
Follow all safety guidelines listed in the user's manual.
CAUTION
In the unlikely event that the heat pipe should leak:
DO NOT attempt to put out the fire with water or chemical fire extinguishers.
SMOTHER THE FIRE WITH DRY SODA ASH
See the MSDS at the back of this manual.
WARNING
CALIBRATION EQUIPMENT SHOULD ONLY BE USED BY TRAINED PERSONNEL.
d

Table of Contents
1 Introduction ................................9
2 Specifications and Environmental Conditions ............11
2.1 Specifications...................................11
2.2 Environmental Conditions ............................11
2.3 Warranty .....................................11
3 Safety Guidelines ............................13
4 Installation ................................15
4.1 Unpacking ....................................15
4.2 Location .....................................15
4.3 “Dry-out” Period .................................15
4.4 Power.......................................15
4.5 Plumbing .....................................15
4.6 Heat Pipe Installation...............................15
5 Parts and Controls............................17
5.1 Control Panel...................................17
5.1.1 Controller...........................................17
5.1.2 System Fuses ........................................18
5.2 Furnace Core...................................18
5.3 Access Well ...................................18
5.4 Back Panel ....................................18
6 General ..................................21
6.1 Sodium Heat Pipe Information ..........................21
6.1.1 Minimum Temperature and Heat-Up Rate ..........................21
6.1.2 Safety Precautions ......................................21
6.1.3 Life Expectancy .......................................21
7 Controller Operation...........................23
7.1 Well Temperature.................................23
7.2 Temperature Set-point ..............................23
7.2.1 Programmable Set-points ..................................23
7.2.2 Set-point Value........................................23
7.2.3 Temperature Scale Units...................................25
7.3 Scan .......................................25
v

7.3.1 Scan Control .........................................25
7.3.2 Scan Rate ..........................................25
7.4 Ramp and Soak Program ............................25
7.4.1 Program Points........................................25
7.4.2 Number of Program Points..................................25
7.4.3 Editing Program Set-Points .................................26
7.4.4 Program Function Mode ...................................26
7.4.5 Program Control .......................................27
7.5 Secondary Menu .................................27
7.6 Heater Power...................................27
7.7 Proportional Band ................................27
7.8 Controller Configuration .............................28
7.9 Operating Parameters ..............................28
7.9.1 High Limit ..........................................28
7.9.2 Soft Cut-out .........................................28
7.10 Serial Interface Parameters ...........................28
7.10.1 BAUD Rate..........................................29
7.10.2 Sample Period ........................................29
7.10.3 Duplex Mode .........................................29
7.10.4 Linefeed ...........................................29
7.11 Calibration Parameters..............................30
7.11.1 Hard Cut-out .........................................30
7.11.2 DC1 .............................................30
7.11.3 DC2 .............................................30
8 Digital Commmunication Interface ...................31
8.1 Serial Communications..............................31
8.1.1 Wiring ............................................31
8.1.2 Setup.............................................31
8.1.2.1 BAUD Rate.....................................31
8.1.2.2 Sample Period ...................................31
8.1.2.3 Duplex Mode....................................32
8.1.2.4 Linefeed ......................................32
8.1.3 Serial Operation .......................................32
8.2 Interface Commands ...............................32
9 Freeze Point Realization ........................35
9.1 General......................................35
9.2 Installing the Metal Freeze Point Cell.......................35
9.3 How to realize the freezing point of silver ....................35
9.4 Safety Precautions ................................37
10 Maintenance ...............................39
11 Troubleshooting .............................41
vi

11.1 Troubleshooting..................................41
11.1.1 Incorrect Temperature Reading ...............................41
11.1.2 The unit heats slowly.....................................41
11.1.3 If the display flashes any of the following: “err 1–err 5” ...................41
11.1.4 If the display flashes “err 6” .................................41
11.1.5 If the display flashes “err 7 or err 8” .............................41
11.2 Wiring Diagram..................................42
vii
Figures and Tables
Figure 1. Front Control Panel (cover door remove) ...................17
Figure 2. Furnace Core Diagram ............................19
Figure 3. Back Panel ..................................20
Figure 4. Controller Operation Flowchart ........................24
Figure 5. Serial Cable Wiring ..............................31
Table 1.Digital Communications Commands ......................33
Digital Communications Commands continued.....................34
Figure 6. Metal Freeze Point Cell installed in canister .................36
Figure 7. Testing Uniformity ...............................40
Figure 8. Wiring Diagram ................................42

1 Introduction
The Hart Scientific Model 9115 Furnace has a tem-
perature range of 550° C to 1000° C and is designed
for use in achieving Aluminu or Silver Freezing Point
measurements.The Model 9115 may also be used to
make comparison measurements using a specially
designed quartz/graphite equilibration block.
The furnace utilizes a sodium heat pipe to maintain a
uniform temperature over the length of the Metal
Freeze point cell. The temperature controller is pro-
grammable,afeaturethatmaybeconvenientlyusedto
simplify the melting, freeze initiation, and plateau con-
trol.The temperature control and uniformity of the fur-
naceallowstheusertoachieveplateausrangingmany
hours in length.
Note: Many of the illustrations and examples used in
this manual assume the use of the silver point cell.Ei-
ther ofthe cellsindicatedmaybeused withtheappro-
priate set-points.
Model 9115 Manual Rev. 761301 9

10 Manual Rev. 761301 Model 9115

2 Specifications and Environmental
Conditions
2.1 Specifications
Operating Range 550°C to 1000°C
Set-Point Resolution 0.1°C
Display Resolution 0.1°C below1000°C, 1°C
above 1000°C
Heater Power 2500 watts
Exterior Dimensions Height: 33 inches
Width: 24 inches
Front to Back: 16 inches
Power Requirements 230 VAC (±10%), 50/60
Hz, 1 Phase, 12 Amps
Shipping Weight 130 lb.
2.2 Environmental Conditions
Although the instrument has been designed for opti-
mum durability and trouble-free operation, it must be
handled with care.The instrument should not be oper-
ated in an excessively dusty or dirty environment.
Maintenance and cleaning recommendations can be
found in the Maintenance Section of this manual.
The instrument operates safely under the following
conditions:
•temperature range:5 - 50°C (41 - 122°F)
•ambient relative humidity:15 - 50%
•pressure: 75kPa - 106kPa
•mains voltage within ± 10% of nominal
•vibrations in the calibration environment
should be minimized
•altitude does not effect the performance or
safety of the unit
If the unit is operating at temperatures above 600°C,
cooling coils are accessible on the rear of the chassis
to prevent the furnace heat from loading down the
roomairconditioningsystem.(SeeSection4.5Plumb-
ing)
2.3 Warranty
The 9115 Metrology furnace is covered bya1year
warranty that takes effect 10 days after the product is
shipped.Themanufacturerwillprovidepartsandlabor
without charge for repair or replacement of the instru-
ment due to defects in material or workmanship. The
warrantywillnotapplyiftheproducthasnotbeenused
according to the instruction manual or has been tam-
pered with by the user. For service or assistance,
please contact the manufacturer.
Hart Scientific, Inc.
799 East Utah Valley Drive
American Fork, UT 84003-9775
Phone:[phone] Fax:[phone]
E-mail: [e-mail]
Model 9115 Manual Rev. 761301 11

12 Manual Rev. 761301 Model 9115

3 Safety Guidelines
•Operate the instrument in room temperatures
between 5-50°C (41-122°F). Allow sufficient
air circulation by leaving at least 6 inches of
space between the furnace and nearby ob-
jects.Nothing should be placed over the top of
the furnace.The furnace should not be placed
under cabinets or tables. Extreme tempera-
turescanbegeneratedoutthetopofthewell.If
the furnace is equipped with cooling coils, use
coldwatercirculationwhenthefurnaceisused
above 600°C. (For specifics see Section 4.5
Plumbing.)
•The furnace is a precise instrument. Although
it has been designed for optimum durability
and trouble free operation, it must be handled
with care.The instrument should not be oper-
ated in wet, oily, dusty or dirty environments.
Keep the well of the instrument free of any for-
eign matter. Do not operate near flammable
materials.
•TheModel9115Furnaceutilizeshighvoltages
and currents to create high temperatures.
Caution should always be maintained during
installation and use of this instrument to pre-
vent electrical shock and burns.Fire can be a
hazard for any device that produces high tem-
peratures. Proper care and installation must
be maintained.Responsible use of this instru-
ment will result in safe operation.
•Do not use fluids to clean out the well.
•Thefurnace generates extremetemperatures.
Precautionsmustbetakentopreventpersonal
injuryordamagetoobjects.Probesmaybeex-
tremely hot when removed from the furnace.
Cautiously handle probes to prevent personal
injury. Carefully place probes on a heat resis-
tant surface or rack until they are at room tem-
perature. SPRT’s should be placed in an
annealing furnace if removed at temperatures
greater than 500°C.
•UseonlygroundedACmains supplyofthe ap-
propriate voltage to power the instrument.The
furnace requires 12 amps at 230V (±10%),
50/60 Hz.
•Before initial use, after transport, and anytime
the furnace has not been energized for more
than 7 days, the instrument needs to be ener-
gized for a “dry-out” period of 1-2 hours before
it can be assumed to meet all of the safety re-
quirements of the IEC 1010-1.
•The instrument is equipped with operator ac-
cessible system fuses. If a fuse blows, it may
be due to a power surge or failure of a compo-
nent.Replacethefuseonce.Ifthefuseblowsa
second time, it is likely caused by failure of a
component.If this occurs, contact Hart Scien-
tific Customer Service. Always replace the
fuse with one of the same rating, voltage, and
type. Never replace the fuse with one of a
higher current rating.
•If a main supply power fluctuation occurs, im-
mediately turn off the furnace. Power bumps
from brown-outs and black-outs can damage
the instrument. Wait until the power has stabi-
lized before re-energizing the furnace.
•The unit is not equipped with wheels.It is con-
sideredtobepermanentlysetonceithasbeen
installed. If the unit must be moved for some
reason, be sure that the fixed point cell has
beenremovedbefore movingthe furnace.Any
movement of the furnace with the cell inside
can damage the cell.The unit is not designed
tobeliftedorcarried.Ifitmustbepickedup,itis
advisable that two people pick the unit up by
placingtheirhandsundertheunitandcarefully
lifting at the same time. Never move the fur-
nace if it is hot.
•Air circulated through the gap surrounding the
furnace core keeps the chassis cool.DO NOT
SHUT OFF THE FURNACE WHILE AT HIGH
TEMPERATURES. The fan will turn off allow-
ing the chassis to become hot.Alternatively, if
used, the cooling water should remain on until
the furnace is cool.
•Oncethe unithas been takentohigh tempera-
tures (over 800°C), it takes days for the unit to
cool completely.
•CAUTION
In the unlikely event that the heat pipe should
leak, do not attempt to put out the fire with wa-
ter or chemical fire extinguishers.Smother the
fire with dry soda ash in accordance with the
MSDS sheets at the end of this manual.
Model 9115 Manual Rev. 761301 13

14 Manual Rev. 761301 Model 9115

4 Installation
4.1 Unpacking
Verify that the following components are present:
•Furnace
•Radiation Guard (Quartz tube packed sepa-
rately)
•Fixed Point Basket
•Fixed Point Basket Lid
•Fixed Point Basket removal tool
•Sodium Heat Pipe
•Extra Insulation:
•Paper for the fixed point cell
•Small circles for fixed point basket
•Miscellaneousforpackingaroundthefixed
point cell
Unpacking should be done carefully.Several parts are
packed disassembled for safe shipment. Small parts
may be packed in a separate box inside the crate.
Checkcarefullyforallparts.Ifthereisanydamagedue
to shipment, notify your carrier immediately.
4.2 Location
A furnace of this type is typically installed in a calibra-
tion laboratory where temperature conditions are gen-
erallywellcontrolled.Bestresultswillbeobtainedfrom
this type of environment. Avoid the presence of flam-
mable materials near the furnace. Allow 6 or more
inches of air space around the furnace.Adjust the lev-
elers on the bottom of the furnace to level the furnace
and to keep it from rocking.
4.3 “Dry-out” Period
Before initial use, after transport, and any time the in-
strumenthasnotbeenenergizedformorethan7days,
the unit needs to be energized for a “dry-out” period of
1-2 hours before it can be assumed to meet all of the
safety requirements of the IEC 1010-1.
4.4 Power
The 9115 furnace requires approximately 12 amps of
current at a nominal 230 VAC (±10%) 50/60 Hz. The
furnace is supplied with a 14-gauge, 2-conductor plus
ground cable and connector. Since building electrical
installationsmayvary,theconnectorandcablemaybe
removed at the furnace back panel and another used
so long as it is rated for the specified current and volt-
age. (See Figure 3, Back Panel on page 20.)
Be sure that the furnace chassis is always solidly
grounded. A shock hazard may exist if it is not. All
switches are double pole for safety in such hot-hot-
neutral installations and both lines are fused.
4.5 Plumbing
Thecoolingcoilsareaccessiblefromthebackpanelof
the 9115 chassis (See Figure 3, Back Panel on page
20). Water cooling prevents much of the furnace heat
from loading down air conditioning systems. Provide
cold tap water with a valve convenient for operation
near the rear of the furnace. A flow rate of about 0.4
GPM of tap water is required.Pressure should not ex-
ceed60PSIG.Drainthewarmexitwaterintoanappro-
priate sump.
4.6 Heat Pipe Installation
Note: The first heat of the furnace should be done
without the heat pipe to verify operation and to be-
come familiar with the furnace. Remove any pack-
ing material before operating.
Theheatpipeisshipped separatelyinorder to prevent
damage to the heater and delicate fiber ceramic insu-
lation. Re-installation of the temperature control and
cut-out thermocouples as well as the pre-heat well as-
sembly is also required. Follow the instructions care-
fully.Manyofthematerialsarefragile.RefertoFigure2
on page 19.Should the furnace be relocated, the heat
pipe must be removed and reinstalled at the new loca-
tion. See Figure 2 which shows the internal compo-
nents of the furnace core.
1. Remove the top cover of the furnace. Observe the
thermocouples, pre-heat wells and top support block
that were put in place for shipment. Remove them in
preparation for heat pipe installation.The thermocou-
Model 9115 Manual Rev. 761301 15

ples do not need to be electrically disconnected. They
are positioned by a metal retaining plate that is located
with 4 screws.These assemblies must be replaced into
the same locations and position after insertion of the
heat pipe.Remove any packing material that may have
been used for shipment.
2. Locate the heat pipe and the heat pipe installation
tool. Use cotton gloves to handle the heat pipe. Finger
prints will cause corrosion of the Inconel at high tem-
peratures.The installation toolhas ahandle with heavy
gaugewirehookswhichfitintothetabsonthetopofthe
furnace. Remove any packing materials from the heat
pipe.
(Anyfinger oilsmustbe removedwith alcohol bef-
ore installation.) The heat pipe has a protrusion on the
top between the installation tabs which served as a fill-
ing port. This port must be rotated appropriately to fit
the matching notch on the top support block. Note the
orientation of the notch onthe top support blockand be
sure to rotate the heat pipe accordingly. The larger
notches in the top support block are toward the rear of
the furnace.
3.Attachtheinstallationtooltotheheatpipeandlowerit
very carefully into thefurnace.Maintainthe heat pipe in
the center of the well so as to allow the bottom support
block to slide into the cavity at the bottom of the heat
pipe. The fiber-ceramic material is very fragile. The
heater and the support can easily be damaged if care
is not taken during heat pipe installation.
4.Once the heat pipe is in place, Position the top sup-
port block over it.Use the extra 0.25 inch fiber ceramic
blanket material provided to center and firmly locate
the top support. Use a knife to cut this material to the
appropriate size, then slide it into place with the top
support.
5. Using the 4 screws, reinstall the metal retaining
plate over the access well and preheat tubes.
6.Reinstall the thermocouples.They must be inserted
far enough to clear the top cover.They should also be
centeredinthe airspacebetweentheelement andthe
heat pipe. Small pieces of the fiber ceramic material
can be used to fix their positions.
7.Reinstallthetopcover.Locatethecoverovertheball
catches and press down firmly.Verify the alignment of
thepreheatwellaccessholeswiththequartztubesbe-
low.
8. Become familiar with the operation of the furnace
before installing the metal freeze point cell. Use the
program installed in the furnace if desired.
16 Manual Rev. 761301 Model 9115

5 Parts and Controls
The Model 9115 consists of a control panel, furnace
core, and a back panel. Each part and control is de-
scribed below.
5.1 Control Panel
The controls to the furnace are located on panels to
the right of the instrument. The upper portion of the
panel is sloped and contains the controller which is
regularlyusedduringoperationofthefurnace.Agreen
LED on the main display indicates the unit is ener-
gized.Beneath the controller is the power switch.The
system fuses are behind a hinged door under the
power switch.
5.1.1 Controller
The controller has overall control of the furnace. This
slopedpanelislocatedontheupperrightportionofthe
furnace (see Figure 1).The controller itself is a hybrid
analog/digital device utilizing the high stability of ana-
log circuitry with the flexibility of a micro-processor in-
terface and digital controls.
The following controls and indicators are present on
theprimarycontrollerpanel:(1)thedigitalLEDdisplay,
(2) the control buttons, and (3) the power indicator
light.
(1) The digital display shows the set and actual tem-
peratures as well as various other functions, settings
and constants. The temperature can be set in scale
units of either °C or °F.
(2) The control buttons (SET, DOWN, UP, and EXIT)
are used to set the furnace temperature setpoint, ac-
cess and set other operating and calibration parame-
ters.
A brief description of the functions of the buttons fol-
lows:
SET - Used to display the next parameter in a menu
and to store parameters to the displayed value.
DOWN - Usedto decrementthe displayedvalueof pa-
rameters.
UP - Used to increment the displayed value.
EXIT - Used to exit from a menu. jWhen “EXIT” is
pressed any changes made to the displayed value are
ignored.
Model 9115 Manual Rev. 761301 17
SET UPDOWN EXIT
HART
SCIENTIFIC
419.03 C
POWER
9115
FREEZE POINT
FURNACE
O
I
FUSES
15 AMP
Figure 1. Front Control Panel (cover door remove)

(3) TheLEDindicatorletstheuservisuallyseethatthe
unit is energized.
5.1.2 System Fuses
Foreasyaccessbytheuser,thesystemfusesofappro-
priate amperage (15 A) are located behind the door of
the lower panel. See Section 3 Safety Guidelines with
regard to changing the fuses.
5.2 Furnace Core
The furnace core consists of the heater, insulating ma-
terials, heat pipe, heat pipe support blocks, and the
housing with water cooling. Refer to Figure 2 on page
19.
The heater operates on a nominal 230 volts AC and
generates2500wattsofpower.Itisembeddedinafiber
ceramic insulating block. A hollow section through the
center contains the heat pipe.
The heat pipe is a double wall Inconel cylinder contain-
ing sodium. The minimum working temperature of the
Sodium heat pipe is about 500°C. The heat pipe must
be heated slowly (about 1-2 hours) to this temperature.
Thetemperaturemaythenberaisedmorequicklytothe
desired set-point. When the working temperature is
achieved, the sodium circulates throughout the tube
providing a uniform temperature. The heat pipe has a
lifetime of many years.Do not use the heat pipe unnec-
essarily at high temperatures which reduces the life-
time.Refer to the Section 6 for more information.
Caution: In the unlikely event that the heat pipe
should leak, do not attempt to put out the fire with
water or chemical fire extinguishers. Smother the
fire with dry soda ash in accordance with the
MSDS sheets at the end of this manual.
The heat pipe is centered in the heating element and
supported by means of fiber ceramic blocks.One block
fits into the bottom of the heat pipe and a second fits
over the top centering the heat pipe in the heater as-
sembly.Thetopblockalsosupportsthethermocouples.
The heat pipe is shipped separately since its weight
would damage the heater and supports if it were in
place during shipment.
The entire heater and heat pipe assembly are con-
tained and supported by a sheet metal housing.Cop-
per cooling coils are attached to the outside of this
housing. These cooling coils allow some of the heat
lost to be removed from the lab area reducing the lab
heat load. They are accessible on the rear of the fur-
nace chassis (see Figure 3).
Air is circulated through the gap surrounding the fur-
nacecore.This keepsthe chassis cool.Do not shutoff
the furnace while at high temperatures or the fan will
turn off allowing the chassis to become hot. Alterna-
tively, if used, the water cooling could remain on until
the furnace is cool.
5.3 Access Well
Thefurnaceaccesswellisvisibleontopofthefurnace.
The furnace access well is where the freeze point cell
is inserted and removed from the furnace. After a
freeze point cell is inserted into the furnace, a thermal
shunt disk and thermal guard assembly are installed
over it.This provides a block to the heat loss from the
well and provides more temperature uniformity for the
cell.
5.4 Back Panel
The back panel consists of an exhaust fan, a serial
communicationsconnector,a powercord, and cooling
water ports. See Figure 3 on page 20.
1. The exhaust fan allows air circulation around the
electrical components.Be sure to keep this fan free of
foreign objects that could hinder air flow.
2. The serial communication connector is a DB-9
connector for interfacing the furnace to a computer or
terminal with serial RS-232 communications. (See
Section 8 starting on page 31 for details.)
3. The power cord is a non-removable cord of AC
voltage (230 VAC ±10%).
4. Thecooling waterportsare providedforconnect-
ing to cooling water to reduce the heat load.See Sec-
tion 4.5 Plumbing for details.
18 Manual Rev. 761301 Model 9115

Model 9115 Manual Rev. 761301 19
SPRT
Thermal Guard
Assembly
Top Support
Block
Retaining Plate
Top Cover
Cutout Thermocouple
Cooling Coils
Heating Element
Thermal Shunt Disk
Control and Cutout
Thermocouple
Metal Freeze Point Cell
Basket and Cover
Metal Freeze Point Cell
Heat Pipe
Ceramic Fiber
Insulation
Air Gap
(Circulating Air)
Bottom Support
Block
Figure 2. Furnace Core Diagram

20 Manual Rev. 761301 Model 9115
Fan
Communication
(RS-232)
Power Cord
Water Cooling
Connection
Current Voltage
Label
Figure 3. Back Panel

6 General
6.1 Sodium Heat Pipe
Information
6.1.1 Minimum Temperature and Heat-
Up Rate
Theheatpipeshouldnotbeinsertedintoahotfurnace.
The minimum operating temperature is 500°C. The
heat pipe should be installed in a cold furnace and
heated to the minimum operating temperature over a
minimum1 hourperiod.Abovethe minimumoperating
temperature the heat-up rate is not important.
6.1.2 Safety Precautions
The heat pipe was designed for long-term mainte-
nance free operation.It was performance tested at the
factory and in the furnace.
Inthe eventof anaccident whichresults ina rupture of
the heat pipe, the small quantity of sodium may burn.
DO NOT use water or standard fire extinguishers on
sodium fires.(Refer to MSDS) Standard commercially
available materials for extinguishing sodium fires are
dry soda ash (Na2CO3) or powdered graphite.
A con-
tainer of one of these products should be kept in the
laboratory near the furnace in case of an accident.
Mechanical damage to the fill tube may cause in-
leakage of air at low temperatures. This will evidence
itselfbycoldregionsintheheatpipewhenatoperating
temperature. Operation should be discontinued and
HartScientificCustomerServiceshouldbeconsulted.
6.1.3 Life Expectancy
The heat pipe is designed for a minimum of 2 years of
operation at 1040°C. The heat pipe will function for a
short-time(1000 hours)at1100°C. Arecord shouldbe
kept of time of operation at or near the maximum
temperature.
Model 9115 Manual Rev. 761301 21