Operation and Calibration of Vacuum Oven

1.  Objective

To lay down a procedure for operation and Calibration of vacuum oven. It is used for determination for loss on drying.

• Scope

This SOP is applicable for operation of vacuum oven (Make: LABCO) in Quality Control.  

• Responsibility

QC Chemist / Officer : Follow the procedure and maintain record as applicable.   

• Accountability

Head Quality Control  : System Compliance

• Procedure:  
  • Operation:
    • Ensure that vacuum oven is clean.
    • Check the calibration due date.
    • Ensure that vacuum pump is attached properly.
    • Open the door, place the sample and close the door tightly.
    • Switch ON the mains.
    • Switch ON the oven by pressing the green main indicator switch downwards.
    • Set the temperature on the temperature gauge by pressing Ú or Ù and then press enter key.
    • On the vacuum pump, open the valve and let it attain the required vacuum in mm Hg.
    • After attaining the required vacuum close the valve and off the vacuum pump.
    • Start the heater by pressing red load indicator switch downwards.
    • Control the speed of heating by rotating the regulator knob at desired rate.
    • After completion of work press the red load indicator switch to upward to off the heater.
    • Then release the vacuum by opening the valve.
    • Finally press the green main indicator switch to upward to off the oven.
    • Open the door, remove the sample and close the door.
    • Enter the details in Instrument log.
    • In case any problem exists inform to Engineering Department.
    • Sample placed time in vacuum oven and withdrawn time from vacuum oven and actual temperature shall be recorded on test data sheet.
  • Calibration:
    • Operate the equipment.
    • Set the vacuum at pressure 760mm/30inch.
    • Set the temperature of oven at 60ºC.
    • Insert the calibrated thermometer (110 ºC) from the side hole.
    • Leave the instrument till the desired temperature is obtained.
    • Record the reading of thermometer on annexure I.
    • Similarly raise the temperature to 100 & 105ºC and record the observation on annexure I.
    • Acceptance Criteria: All the observed reading should be within limit of ±1°C.
    • Prepare the calibration tag and affix it with equipment.
    • Attach the old calibration tag with the record and do not throw it.
    • Frequency: 6 months ± 3 days.
    • If the variation is not within the specified tolerance limits:
      • Label the equipment with a tag, “OUT OF CALIBRATION”.
      • Inform the Department Head.
      • Do not use equipment until all errors are rectified. After rectification, again calibrate the equipment & record the observation.
    • Note: Vacuum Gauge & Temperature Controller is calibrated by external Agency at-least once in a six month.
• Annexure (S)           

NA

• Reference (S)

In-house

• Glossary

SOP            :    Standard Operating Procedure

QA              :    Quality Assurance

QC              :    Quality Control

ºC               :    Degree Celsius

mm             :    Millimeter

• Revision History

Rev. No.	Details of changes	Reason for change