SOP FOR OPERATION AND CALIBRATION OF VISCOMETER

1. OBJECTIVE:

1. To lay down the procedure for Operation and Calibration of Viscometer.

2. SCOPE: 

1. This procedure is applicable for the Operation & Calibration of Viscometer 

3. RESPONSIBILITY: 

1. Quality Control Officer / Executive are responsible to follow procedure as per the procedure mentioned in this SOP. 

2. QC Head is responsible for implementation and compliance of the procedure as per this SOP.

4. ABBREVIATIONS

1. SOP    :    Standard Operating Procedure

2. QC    :    Quality Control

3. cP        :    centipoises 

4. mPs    :    Millipascal second

5. FSR    :    Full scale reading

5. PROCEDURE: 

1. Procedure For Operation

1. Ensure that the working bench and instrument is clean.

2. Ensure that the viscometer is leveled. The level is adjusted using the two leveling screws on the base. Adjust so that the bubble level on the top of the viscometer is centered within the circle.   

3. Level of the viscometer shall be checked periodically during operation.

4. Remove the white shipping cap which secures lower coupling nut.

5. Switch on the power and allow to warm up for about 10 minutes before auto zeroing.

6. Remove the spindle and press any key, auto zero in started.

7. Cp/mps 0.0 temp, off RPM, torque % 0.0 is displayed.

8. Place the spindle by screwing onto the lower shaft. The spindles have left hand thread. 

9. Slightly lift the screw upward and screw the spindle. 

10. Speed Selection: Press up and down keys to select the speed. Press the set speed key after the desired speed is achieved.

11. Display Selection: Press select display key to select viscosity (Cp/mPa.s), shear stress (SS) in dynes/cm2 or newtons/m2 and shear rate (SR) in 1/sec. After selection press the select display key again.

12. Measurement of viscosity: 

1. Mount the guardleg on the viscometer and insert into the container.

2. Insert the spindle in the test material until the fluids level in at the point of immersion groove on the spindle shaft. Precaution is necessary to avoid air bubble trapping on the lower surface of spindle surface.

3. Lift the shaft slightly up and screw the spindle which is having left hand thread.

4. Ensure that the viscometer is in level and spindle is immersed in the liquid at the specified depth before operation.

5. Selection of the spindle and speed:

6. Viscosity range is inversely proportional to the size of the spindle.

7. Viscosity range is inversely proportional to the rotational speed.

8. For high viscosity, choose a small spindle and slow speed.

2. Procedure For Calibration

1. Operate the instrument as per the operation procedure.

2. Place the viscosity standard fluid on the water bath.

3. The viscosity standard fluid should be kept on the bath till the temperature reach to 25°C±2°C. Stir the fluid periodically, prior to taking readings.

4. After one hour check the temperature of the fluid with an accurate thermometer.

5. Take the reading of actual viscosity at 25°C±1°C. And also take the readings for % torque, maximum range of cP i e FSR, Minimum cP, spindle type. The viscosity readings should be within the combined accuracies of the viscometer and the viscosity standard.

6. Record the observations in the Monthly Calibration of Viscometer Record (Annexure I).

7. The accuracy of the viscometer is ±5% of the full scale range of the meter for the given fluid at specified temperature and with the operating spindle.

8. The accuracy of the standard fluid is ±5% of the certified viscosity of the fluid.

9. If the instrument is out of calibration, tag the instrument with the following label. And inform to the service engineer for rectification.

10. Calibrate the instrument after rectification.

11. Frequency: Quarterly.