Loma Products & Services > Temperature Measurement > Guide to Microwave Temperature Measurement
This revolutionary technology was initially used in the field of astrophysics, measuring the minute amounts of microwave energy emitted by stars and planets. The technology was then adapted for medical diagnostics, measuring ‘hot spots’ in tissue. It was highly successful due to its passive, non-invasive technology, inherent safe nature, simplicity and speed.
Anything that can absorb radiation also emits radiation. To measure this Celsius employs advanced microwave radiometry technology. This is the measurement of the wavelength component of natural thermal radiation emitted by all organic objects.
This thermal radiation is generated by the random motion of molecules. The Celsius receiver detects these thermal signatures which can be in the thousands depending on the product. It then takes these readings and computes the average temperature shown providing the desired equilibrium temperature.
To obtain a reading the product is simply placed inside a cavity, a door is closed, which provides an RF seal to stop any external interference. The microwave signals that are emitted buy the food are measured by the cavity antenna, these are extremely small, about 100 nano watts (100x10-9 watts).
In the receiver the signals are amplified by special microwave amplifiers with exceptionally good signal to noise ratios. With this method all temperature variations within the product are measured and processed. This is done with a greater accuracy then probes or infrared in far less time and with no human error.
Food products typically contain a variety of different components, which are subject to numerous external temperature influences throughout the process. This leads to temperature variations, whose gradient will vary from product to product. Any area of the product that falls out of these safe temperature parameters can effect the safety of the product and can influence its overall (equilibrium) temperature.
In summary
- Any temperature tool that takes only one area or point of the product is liable to miss these hot and cold spots.
- Additionally any temperature measurement tool that relies on human skill to place the probe consistently in the same place or take multiple measurements to check all temperature variations is a limitation.
- Any time consuming technique from temperature measurement tests and/or penetrative measurements will unnaturally effect the end result.
Limitations of thermal probes and infrared surface measurement
Despite the limitations thermal probes present this was the only traditional method available to manufacturers to ‘measure’ product temperature. This process though has associated costs both in terms of product wastage, high consumable costs and (along with limited infrared surface temperature measurement) the potential for over chilling, freezing and cooking of products as a result of manufacturers not having an accurate reading of product temperature.
