Calibration of Viscometer, Purpose :
Calibration of Viscometer, The purpose of this SOP is to describe the operation, calibration and cleaning of viscometer (Model: Brookfield LVDV-II+Pro) used for the measurement of viscosity in the quality control laboratory at XX Pharmaceuticals Ltd.
Calibration of Viscometer, Scope :
This procedure is applicable to the Brookfield viscometer, installed in the quality control laboratory of XX Pharmaceuticals Limited.
Definitions/Abbreviation:
[][]Standard Operating Procedure (SOP): A written authorized procedure, which gives instructions for performing operations.
[][]Viscosity: Viscosity is measure of fluid’s resistance to flow.
[][]FSR: Full Scale Viscosity Range.
[][]cP: Centipoise
Responsibilities:
The roles and responsibility is as follows:
Officer/Executive/Sr. Executive, Quality Control
[][]To ensure that this procedure is followed.
[][]To maintain the records properly as per SOP.
Manager, Quality Control
[][]To ensure that this procedure is kept up to date.
[][]To confirm that the SOP is technically sound and reflects the required working practices.
[][]Arrange training on the SOP to all concerned personnel.
[][]To ensure implementation of the SOP after training.
[][]Schedule calibration of the instrument at the defined intervals.
Head of Quality Assurance
[][]Approval of the SOP.
[][]To ensure overall implementation of this SOP.
Procedure:
Precaution(s):
[][]To measure high viscosity, choose a small spindle or select slow speed.
[][]Remove spindle before cleaning.
[][]Prior to operation check the labeling of the viscometer. The label is adjusted using the two leveling screws on the base. Adjust so that the bubble label on the top of the instrument within the circle.
[][]Viscosity measurements should be accepted within the equivalent % of Torque Range from 10% to 100% for any combination of spindle/speed rotation.
[][]Viscosity measurements should be taken under laminar flow conditions, not under turbulent flow conditions.
Calibration procedure:
[][]Switch on the power from its main and power on the viscometer.
[][]Transfer the viscosity standard fluid (Standard Fluid 10, Standard Fluid 500 & Standard Fluid 5000) into 600 ml beaker.
[][]Immerse the beaker along with the spindle into water bath for 1 hour at set temperature 25.0°C.
[][]After 1 hour, check the temperature of the viscosity standard fluid with an accurate thermometer.
[][]Lower the DV-II+ into measurement position of the guard leg.
[][]Attach the spindle to the viscometer. In case of disk – shaped spindle, avoid trapping air bubbles beneath the disk by first immersing the spindle to an angle and then connecting to it to the viscometer.
[][]Measure the viscosity reading normally at 25.0°C ± 0.1°C, must rotate the spindle at least five times before readings are taken.
[][]The viscosity reading should be equal the cP value on the fluid standard to within the combined accuracies of the viscometer & viscosity standard i.e. ± (1% of full scale viscosity range + 1% viscosity Standard Fluid stated value at 25ºC).
[][]Calculate the Full scale viscosity is determined from following equation:
[][]Full scale viscosity [cP] = TK * SMC * 10000/ RPM
Where,
TK = spring torque constant of viscometer (for LVDV-II +Pro model TK value is 0.09373 )
SMC = spindle multiplier constant for spindle [SMC value for the four spindle LV1 (entry code: 61), LV2 (entry code: 62), LV3 (entry code: 63), LV4 (entry code: 64) and LV5 (entry code: 65) are respectively 6.4, 32, 128, 640 and 1280.]
[][]RPM: Rotation per minute Compile the result & take approval for the calibration information sheet (Annexure-I).
[][]Carry out the test once in a year.
[][]Affix the label “CALIBRATED” on the instrument if all test results are satisfactory.
[][]If the equipment found out of calibration limit affix “UNDER Maintenance” label and inform the respective Supplier.
Operating procedure:
[][]Check the machine is clean & calibrated.
[][]Make the switch ON of the viscometer.
[][]Let the machine initialize for 10 minutes before performing Auto zero.
[][]Attach the spindle with the lower shaft of the viscometer.
[][]Set the spindle no. by pressing SELECT SPINDLE button.
[][]Set speed by pressing SET SPEED button.
[][]Select the data parameters by pressing SELECT DISPLAY button.
[][]Insert and center spindle in the test materials until the fluid’s level is at the immersion groove on the spindle‘s shaft.
[][]Press the motor ON/OFF/ESCAPE key and turn the motor ‘OFF’ when changing a spindle or changing samples.
Cleaning procedure:
[][]After completion of the testing switch ‘OFF’ the instrument and switch ‘OFF’ the mains.
[][]Remove the spindle from the instrument.
[][]Clean the spindle with respective solvent in which solution of sample is prepared.
[][]Clean the spindle with methanol.
[][]Wipe it with tissue paper.
[][]Place the clean spindle at its respective place in the box.
Annexure:
Annexure-I: Calibration Information Sheet for Digital Viscometer
Annexure-II: Calculation Sheet for Viscometer Calibration
Annexure-III: Range for LV Spindle cP (m PaºS )