Standard I.L.L. 1800C Furnace General Description A top loading vacuum furnace with full sample visibility (360 degrees in scattering plane, +-20 degrees out of plane) manufactured by AS Scientific Products Limited Radiative Heating: niobium foil element (2 concentric cylinders 0.05mm thick) driven by high current/SCR power supply 8 thermal shields (0.05mm Nb) and a water cooled aluminum outer vacuum can (1.2 mm thick at neutron window) Active Heating/Sample Zone : 4.2 cm diameter X 10 cm length Temperature Range: Ambient to 1500 C (up to 1800 C for intermittent only) Temperature Control: Auto-tuning PID Type (Eurotherm Model 818) with high current SCR power source Temperature Sensors: type W5 thermocouple (tungsten rhenium alloys: Re5% vs. Re26% ) Interlocked alarm system for pressure, water flow, and temperature

NIST technical assistance is required for furnace set-up Contacts:   Dan Dender (301)-975-6225   Bill Clow (301)-975-5493

Furnace Geometry (not to scale)

Safety Issues Will your sample damage the furnace? The furnace must be operated under high vacuum (less than 10-4 Torr) KNOW YOUR SAMPLE! Researchers must verify that their sample will maintain low vapor pressure (<10E-5 Torr) and not react with its surroundings at high temperature. Safety Interlocks The furnace requires high vacuum and sufficient water flow for safe operation.  There are two safety interlock systems, one is for over-temperature and the other is shared by the vacuum gauge and the water-flow switch.  Familiarize yourself with these circuits and verify their operation. Never operate the furnace if any of these interlocks are not functioning. Set Appropriate Current Limits Do not jolt the furnace with high currrent spikes.  Slowly increment the output limit setting and/or ramp your set-point for smooth operation

Sample Preparation Off-Line Testing All samples and holders should be tested off-line in order to ensure that they can survive the maximum temperatures in your experiment without reacting, bursting, etc. If possible, test your sample before arriving at NIST.  A dedicated test-station is under development at NIST CNR. For now, the AS1800C furnace itself may be used outside of the neutron beam areas and with continuous monitoring and safety precautions for off- line tests. Sample Holders The sample probe terminates with a threaded (M8) stud. Since there are currently no standard sample holders for this furnace, researchers must design (NIST assistance is available) holders compatible with our probes. Ventillated (i.e. non-pressure building) crucible-type holders made of niobium or platinum are recommended. Any sealed sample holder must be tested (off-line) at the maximum desired temperature before loading into the furnace to ensure that an over-pressure burst cannot occur on the beam line. Sample Geometry: Note that the beam center is 40.9cm below the top of the sample well, and the probe height is adjustable to accommodate a wide range of sample sizes. Maximum Sample Diameter=4.2 cm Maximum Sample Height = 12 cm (Note: Distance from top of sample well to heater element = 48 cm.   Your probe/sample length must be adjusted so that you DO NOT HIT THE HEATING ELEMENT!)

FURNACE SET-UP Required Connections Cooling water lines The flow direction is important!  The flow interlock (white fixture connected to orange cable) must be connected to the water RETURN Flow sensor cable (orange w/black connector) to the back of power supply Vacuum Hose from rotary pump (bottom of furnace cart) to turbo pump Notation used below: Furnace connection ---- power/control unit connection { braces denote permanent connections that users should not touch } Penning Pressure Gauge (Lemo connector w/locking nut) ---- {Penningvac PM31 controller} Black 8-Pin Turbo Pump ---- {turbo controller} Blue 6-pin sample probe connector ---- Two T/C connectors Thermocouple conectors (2-prong males) plug into the back of the power unit.  Note the color coding for the leads (blue/white on left, red/orange on right) Green Cable bolts onto turbo pump ---- {Power supply ground} High Current Furnace Leads --- {Power supply} AC Power Cords Three 110 AC cords (turbo controller on power unit, rotary pump on the bottom of the furnace cart, and the solenoid valve on the turbo pump) and the main 210 volt cord for the power supply Alarm Reset at Start-Up Press the "Water/Vacuum Fault" button Orange light goes off if water and vacuum are OK Press the "Overtemp Reset" button Flashing AL1 goes off if the temperature reading is OK

Controller Operation (Eurotherm 818) The NIST CNR instrument control program is set-up for remote setpoint changes with proper ramp rates automatically invoked.  Some important front-panel operations are outlined below "SHORT SCROLL" refers to quick presses of the scroll button which toggle the lower display between SP and OP (set point and output) status.  "LONG SCROLL" refers to pressing and holding until the full parameter set {Pr, SP1, SP2, ... , Sbr } begins to cycle.  Note that a flashing dot indicates that a parameter may be changed using the up/down arrow keys. Set Point SHORT SCROLL (if necessary) to SP mode , press arrow keys to change value (hold arrow key to accelerate change) Output Limit LONG SCROLL to the "Hi" parameter, then immediately press the up or down arrow once to display present setting [% full scale] Press up/down arrows as needed to adjust setting Press scroll to accept value (press repeatedly to scroll back to the default display, or wait ~60 seconds) Refer to the table at the right for proper settings.  When heating from room temperature, increase the hi setting gradually (i.e. DO NOT SUDDENLY DUMP MAXIMUM CURRENT INTO THE FURNACE) Tmax [C]  "hi" setting  500  15  700  18  900  23  1100  29  1300  38  1500  50  Displaying & Changing the Ramp Rate LONG SCROLL to "Pr", press arrow to display present value (rate in degrees/hour), press arrow again to adjust, press scroll to accept, continue scrolling until you return to the default display Note: The short scroll parameter "SP" is equivalent to the long scroll parameter "SP1".  When ramp is active, SP/SP1 is the ramp target or endpoint. Otherwise, SP/SP1 is the static setpoint. Activating a Ramp Press RUN/HOLD key until the display indicates RAMP (this changes to "E" when ramp is complete).  The setpoint will jump to the present temperature and immediately begin ramping to the target (SP/SP1).

Over Temperature Alarm There are three keys along the bottom of the alarm unit (down arrow, scroll, and up arrow) and a "secret key" above the middle digit at the top of the display.  View Alarm Setting The scroll key cycles through three fields {temperature unit, AL 1, and present reading}. When AL1 is selected, press the up or down arrow key to view the present alarm setting in the specified temperature unit (default = 1300 celcius) Change Alarm Setting Press center button until degress C is shown Press the secret key (display now reads "ConF") Press scroll again to cycle through the long parameter list (see table below) Use the up/down arrow keys to change the value of AL1 if necessary.  DO NOT CHANGE ANY OTHER PARAMETERS Parameter Default ConF 6023 id 92 AL 1 1300 Hy 1 10 OFSt 0.0 Line 60

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Last Modified: 4-11-2002