Equipment
Alternatives to Mercury Thermometers
Resistance Temperature Detector (RTD) or Platinum Resistance Thermometer (PRT)
- RTDs, often referred to as PRTs, use a platinum sensor whose electrical resistance increases with temperature.
- PRT probes and readouts can replace mercury-filled thermometers in most cases.
- For high-vibration applications (-100 °C to 150 °C or -148 °F to 302 °F), platinum film sensors on ceramic chips work well.
- For broader temperature ranges or better accuracy, wire-wound PRTs are recommended.
- PRT sensors are typically housed in a metal sheath.
Thermistor
- Thermistors are suitable for temperature measurements from -20 °C to 100 °C (-4 °F to 212 °F).
- They consist of metal oxides with electrical resistance that decreases as temperature increases.
- Glass-coated thermistors offer stability, and they are often mounted in a protective metal sheath.
- Mechanical shocks may damage the glass coating and lead to sensor drift.
Thermocouple
- A thermocouple has two dissimilar metal wires joined to form a measuring junction.
- Thermocouples are best for applications involving shock and vibration.
- They have larger manufacturing tolerances and additional uncertainty in readouts.
- Thermocouples can be insulated with ceramic, fiberglass, or polymer, and can be housed in a metal sheath.
- Suitable for applications where the desired uncertainty is greater than 1 °C (2 °F) and require a mechanically robust or compact sensor.
Organic-Liquid-Filled Thermometers
- Glass thermometers filled with non-hazardous organic liquids are useful within the range of -100 °C to +100 °C (-148 °F to 212 °F).
- Suitable when a desired uncertainty of 0.5 °C (approximately 1 °F) or larger is acceptable.
- Commercially available thermometers use a variety of organic liquids.
- Organic-filled thermometers may experience liquid separation during shipping, extreme temperature use, Careful inspection of the liquid column is necessary under these conditions before use.
Cleaning
CLEANTOOL – Database for alternative cleaning chemicals
Heading 1
Heading 2
Heading 3
This article is a stub. You can help by expanding it. Get Involved!