Standard Operating Procedure for Operation and Calibration of Sub Sieve Sizer
To lay down a procedure for Operation and Calibration of Sub Sieve Sizer.
The scope of this procedure is applicable for Operation and Calibration of Sub Sieve Sizer, (Make Fisher Scientific; Model: 95), located in Quality Control laboratory at [company name].
QC Personnel: To Operate, Clean and Calibrate the Sub Sieve Sizer, To Prepare the Calibration Report.
Section Head- QC/ Designee: To Check the Calibration Report.
Head -QC/Designee: To Approve the Calibration Report.
5.1 The voltage required to run the instrument should be about 115V ± 10 %.
5.2 The manometer tubes and pressure regulator standpipe must be filled with distilled or deionized water, and the drying tube should be filled with a desiccant.
5.3 Use Personal Protective Equipment (PPE) wherever applicable while performing the activity.
5.4 Before plugging the unit into an electrical power source, the back panel should be reinserted into its original position.
5.5 Maintenance/Repairs: If the instrument does not comply with the requirement/acceptance criteria, it should be labeled as “UNDER MAINTENANCE”. The instrument should then be repaired/serviced and recalibrated as per the Calibration SOP.
5.7 Always fill the standpipe with the power switch in the “OFF” position to avoid level errors produced by the effect of the air pump.
5.8 Do not use a cotton plug to replace the original stopper.
5.9 Operating Procedure:
5.9.1 FILLING MANOMETER TUBES – R and U.
- Unplug the unit and remove the back panel of the instrument.
- Loosen the wing nut on the metal retaining plate of the manometer level adjusting assembly just enough so that the plate can be swung out of the way; do not remove the wing nut entirely.
- Swing the retaining plate out of the way by rotating it around the axis of the driving roller. Then, slip the tubing from between the rolls.
- Remove the auxiliary filling tube from the clamps holding it to the inside cabinet and insert one end of it into the open end of the rubber tubing that was removed from the roller assembly.
- Using a jet of water, introduce distilled or deionized water through the auxiliary filling tube and into the manometer tubes (R and U) until the water level in the outside manometer (U) rises to the baseline on the calculator chart.
- Pinch off connections until any air trapped in various rubber connections is released, then check all water levels in all tubes.
- The rubber tubing contains two rubber rings which serve as stops for roller mechanism operation; rollers should operate over section between these stops; with auxiliary filling tube still attached, re-insert rubber tubing between rollers on manometer adjustment assembly (X) such that rollers are at point two-thirds of way toward stop nearest end of tube.
- Starting with rollers about two-thirds distance between two stops on rubber tubing and nearer to stop at end of tubing, adjust MANOMETER LEVEL selector until water level in outside manometer on front panel coincides approximately with baseline on calculator chart; turn selector until water level rises above prescribed point, then turn it until water level falls below prescribed point, and finally turn it until water level falls right on prescribed point.
- After corrected level is obtained in outside manometer, properly place back on rollers and tighten wing nut.
- Then turn MANOMETER LEVEL selector clockwise and counterclockwise to make certain latitude of movement mentioned in above point is still prevalent; then reset water level at proper point.
- Drain excess water from auxiliary filling tube; then remove tube from rubber tubing and re-clamp it to side of cabinet.
- Wipe up any water spilled inside cabinet.
5.9.2 FILLING PRESSURE REGULATOR STANDPIPE
- Make certain that sample tube is not attached to front of instrument and power switch is in “OFF” position.
- Remove stopper from glass intake arm extending through top of instrument.
- Pour distilled or deionized water into the intake arm, filling the pressure regulator standpipe until the water level exactly coincides with the water level mark, as viewed through the water level observation window on the front panel.
- Reinsert the stopper into the inlet arm.
5.9.3 FILLING DRYING TUBE:
- The drying tube should be filled with the supplied indicating drying agent, 10 – 20 mesh Drierite, and ensure that the rubber connection hoses are pushed down securely over the serrated tips of both ends of the tube.
- The supplied desiccant is treated with a substance that indicates the state of dryness of the agent, which can be determined by observing the drying tube through the small window in the left side of the cabinet.
- A BLUE colour indicates that the agent is satisfactory. A PINK colour indicates that the agent must be replaced with a fresh stock.
- To replace the desiccant, UNPLUG THE UNIT and remove the back panel. Remove the drying tube from the clamps that hold it in place. Then remove the cap at the top of the tube, pull out the top layer of glass wool, and pour out the agent from the tube, leaving the bottom layer of glass wool intact. Fill the tube with a fresh stock of 10-20 mesh Drierite, pouring it over the bottom layer of glass wool. Finally replace the top layer of glass wool, recap the tube, and re-clamp it to the inside of the cabinet.
5.9.4 ADJUSTMENT OF SAMPLING PACKING ASSEMBLY:
- To check adjustment of sample packing assembly perform following: i. Set two porous plugs (supplied with sample tube), with two filter papers between them, onto brass post ensuring that lower plug touches upper at end of post. ii. Using rack and pinion control, guide rack down onto top porous plug until flat bottom of rack touches top of upper plug; if adjustment is correct, plugs will be held firmly in place and tip of pointer will coincide exactly with baseline on calculator chart. iii. If adjustment is not correct loosen locknut holding lower brass post in its mount, then adjust height of post by screwing it up or down until correct adjustment is achieved; then retighten locknut.
5.9.5 CHECKING MANOMETER LEVEL:
- When tip of pointer coincides exactly with baseline on calculator chart, initial level of liquid miniscus in manometer must coincide exactly with upper edge of curved portion of metal cross bar attached to rack.
- Turn MANOMETER LEVEL selector until desired level is attained; this must be done without sample tube in place to avoid exerting pressure on liquid in tube which would make adjustment inaccurate.
- Once adjustment is made for particular determination do not disturb MANOMETER LEVEL selector until that determination is complete.
- Check manometer level before each successive determination and correct if necessary.
- All water-level measurements are taken with reference to upper edge of curved portion of cross bar and all chart readings with reference to extreme tip of pointer on same cross bar.
- If water evaporates from manometer restore level by adding distilled or deionized water by means of wash bottle; if necessary to replace original stopper replace it with glass wool.
5.9.6 Calibration Procedure:
- Position unit so front and back are accessible without moving it; remove back of unit.
- Locate HIGH calibration valve (leftmost of two calibration valves as viewed from rear of unit); with range control set to 0-2 to 20 micron position carefully adjust High value marked on calibrator tube.
- Allow the readings to stabilize, and then re-adjust if necessary.
- Locate the LOW calibration value (the rightmost of the two calibration valves as viewed from the rear of the unit). With the Range Control set to the 20 to 50 micron position, carefully adjust the LOW calibration valve.
- Allow the readings to stabilize, and then re-adjust if necessary.
- Set the Range Control to the 0.2 to 20 range, allow the reading to stabilize, then verify the calibration. Re-adjust the HIGH calibration valve if necessary.
- Set the Range Control to the 20 to 50 range, allow the reading to stabilize, then verify the calibration. Re-adjust the LOW calibration valve if necessary.
- Repeat the above steps until both settings are satisfactory.
5.9.7 Sample Preparation:
- Position the sample tube vertically on a flat surface and place a filter paper disk centered on the end of the tube.
- Position a porous plug, perforated end down, onto the center of the filter paper disk. Push the plug into the sample tube until it is even with the end of the tube. The filter paper must fold around the edges of the plug as it is pushed into place.
- Weigh out a sample such that its mass in grams is equal to its true density in grams per cm³.
- Invert the sample tube so that the inserted porous plug is at the bottom; using a powder funnel, transfer all of weighed sample into sample tube.
- Position a filter paper disk centered onto top of sample and insert porous plug.
- Position and hold sample tube on top of brass post beneath rack and pinion with lower plug resting on top of brass post; lower rack until bottom of rack contacts upper porous plug.
- Place spacer adjacent to bottom of brass plug to prevent sample tube from contacting post support block during sample compaction; with sample pressure calibrator attached to rack and pinion control, begin compacting sample by applying torque that produces desired compaction force.
- Slide calculator chart to align sample height line with pointer attached to rack; extreme tip of pointer must align with center of line; do not move chart until sample measurement is complete.
- Read porosity value along bottom of chart where it aligns with appropriate pointer; record this value.
- Transfer sample tube to test position with bottom of tube resting on bottom rubber washer.
- Adjust pressure control until bubble rate is 2 to 3 bubbles per second.
- After manometer level stabilizes, adjust rack and pinion control to align upper edge of cross bar with liquid meniscus in manometer.
- Read particle size from chart.
6.0 Acceptance Criteria:
For range control 0.2 to 20 M (High) : 5.80 ± 0.05 Unit
For range control 20 to 50 M (Low): 2.24 ± 0.05 Unit.
- Operation: As and when required.
- Calibration: Quarterly – 5 Days.
8.0 Format for recording:
8.1 Format for “Instrument Usage Logbook”.
8.2 Format for “Instrument Calibration Protocol”.
Model No. :
Make: Fisher Scientific
Date of Calibration:
Next Due Date:
Calibration of SUB – Sieve Sizer using calibration tube:
|Range Control||Porosity||Result of Partial Size||Limits of Partial Size|
|High||0.2 to 20 M||0.75||5.80 ± 0.05 Unit|
|Low||20 to 50 M||0.75||2.24 ± 0.05 Unit|
Remarks: Calibration Satisfactory / Not Satisfactory
|—||Calibrated By||Checked By||Approved By|