Lesson #3: Comparison of Digital, Chemical and Mechanical temperature monitors
Digital Temperature Monitors: these devices are typically single use or multiple use units. The advantages are high accuracy and the ability to have a full time history information and graph when the capability of downloading information is provided. A time history graph provides temperature information (Y-axis) over the recording time period (X-axis). The drawbacks are higher costs and reliance on battery power.
The following is an example of a typical digital temperature/humidity monitor and a time history graph providing temperature/humidity information:
Chemical Temperature Indicators: these units are mostly single use devices, with average accuracy. Some chemical monitors can be permanently affected by temperature exposure, while others are reversible. Advantages are very low cost and size, while disadvantages include low accuracy and limited temperature ranges.
The following is a sample of a typical chemical indicator:
Mechanical Temperature Monitors: these devices were the only means of obtaining a shipment’s time history graph before digital monitors became available, but nowadays these units are mostly obsolete in the pharmaceutical industry because of their low accuracy and readout resolution; additionally because of the technology’s limitations, temperature data can be affected by shock during transit. Advantages are relative low cost and elemental time history graph which does not require a computer.
The following is a sample of a typical mechanical temperature monitor and time history chart:
