QUANTACHROME INSTRUMENTS MULTIPYCNOMETER Manual page 17

5.5.2. VRa LARGE CALIBRATION (NO SPHERES, LARGE CELL)
5.5.2.1. PERFORM THE STEPS LISTED IN SECTION 5.5.1 (THE PURGE ROUTINE)
WITH THE LARGE SAMPLE CELL IN THE CELL HOLDER.
5.5.2.2. OPEN THE TOGGLE VALVES I AND II AND CLOSE THE GAS IN
TOGGLE VALVE.
5.5.2.3. TURN THE SELECTOR VALVE ON THE FRONT PANEL TO THE CELL
POSITION AND THEN OPEN THE GAS OUT TOGGLE VALVE.
5.5.2.4. TURN THE ZERO ADJUSTMENT KNOB ON THE FRONT PANEL UNTIL A
0.000 PSIG READING IS DISPLAYED ON THE DIGITAL PANEL METER.
5.5.2.5. TURN THE SELECTOR VALVE TO THE REFERENCE POSITION AND
CLOSE THE GAS OUT TOGGLE VALVE.
.
5.5.2.6. OPEN THE GAS IN TOGGLE VALVE AND, WHEN THE DIGITAL PANEL
METER READS 17.0 PSIG, CLOSE THE GAS IN TOGGLE VALVE.
5.5.2.7. VERIFY THAT THE PRESSURE DISPLAYED ON THE DIGITAL PANEL
METER DOES NOT CHANGE DURING A 10-SECOND PERIOD. TAKE THE aP1
PRESSURE READING ON THE DIGITAL PANEL METER AND ENTER THAT
NUMBER ON THE INSTRUMENT CALIBRATION SHEET IN APPENDIX B.2, ITEM
B.2.3., AS aP1.
5.5.2.8. TURN THE SELECTOR VALVE ON THE FRONT PANEL TO THE CELL
POSITION.
5.5.2.9. VERIFY THAT THE NEW PRESSURE DISPLAYED ON THE DIGITAL PANEL
METER DOES NOT CHANGE DURING A 10-SECOND PERIOD. TAKE THE aP2
PRESSURE READING ON THE DIGITAL PANEL METER AND ENTER THAT
NUMBER ON THE INSTRUMENT CALIBRATION SHEET IN APPENDIX B.2, ITEM
B.2.3, AS aP2.
5.5.2.10. CALCULATE THE RATIO aP1/aP2 = aP AND ENTER THIS VALUE AS aP
ON THE INSTRUMENT CALIBRATION SHEET IN APPENDIX B.2, ITEM B.2.3.
5.5.2.11. REPEAT THE STEPS IN SECTIONS 5.5.2.2 TO 5.5.2.11 UNTIL FIVE
CONSECUTIVE aP VALUES FALL WITHIN +/-0.0005 OF EACH OTHER.
NOTE: THE RATIOS CAN BE CALCULATED TO 4 DECIMAL PLACES AND ARE
DIMENSIONLESS, NOT IN PSIG.
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