Refrigeration Instrumentation


  • Good monitoring of refrigeration performance should always be insisted upon.
  • There are a variety of portable instruments available for measuring temperature, air velocity and relative humidity.
  • A thermograph is a clockwork-driven chart recorder, which can record for temperatures a period up to 7 days over a range of –15° to 40°C.
  • A thermohydrograph that can measure temperature (range of –15° to 40°C) and RH (range of 10 – 100% HR ± 3% RH) is also available.
  • ‘Spear” thermometers may be inserted into carcasses and cuts.
  • These consist of either an ordinary mercury thermometer encased in a stainless steel sheath or a bimetallic strip connected to a recording dial.
  • Both types have pointed ends for ease of insertion but are slow in operation and easily damaged.
  • More elaborate electronic and thermistor probe thermometers give more accurate results and are more durable.
  • Instruments, which can record temperature on charts, may be obtained and a thermoanemometer (records temperature and air velocity) is available.
  • Various types of hygrometers and wet-and-dry bulb indicators are manufactured to measure RH, but are slow and liable to damage and contamination of the hygrometric material.
  • A thermohygrograph or a Wet-and-dry indicating psychrometer (range 0-90°C or –10-80°C) gives more accurate measurements.
  • Different types of velometers (anemometers) are available to measure air velocity.
  • The more elaborate are combined with thermometers and are usually more accurate and reliable.
Last modified: Monday, 6 September 2010, 11:28 AM