Recalibration Services

Liquid-in-glass thermometers are extremely accurate, stable, economical and easy-to-use temperature indicating devices. Since their introduction 400 years ago, few engineering changes have altered their function. Unlike their electronic or bimetallic counterparts, liquid-in-glass thermometers:

• Have no moving parts 

• Need no outside power sources 

• Require almost no maintenance 

• They rely solely on their unalterable physical properties of the liquid-in-glass materials of the thermometers. 

When the instrument is heated, the liquid expands and rises up the capillary tube. When it is cooled, the liquid contracts and travels down the capillary.  

Along with expansion and contraction of the liquid column, the thermometer's bulb will expand and contract slightly. After repeated uses, even the highest quality liquid-in-glass thermometer may undergo a slight change in bulb volume due to this expansion and contraction. If a change of this type does take place, the indication of the instrument will also change. Recalibration allows the user of the liquid-in-glass standard to maintain accurate, reliable and consistent results when making temperature measurements.

The answer to this single question has many facets. Some of which are: 

• The frequency of usage  

• Temperature ranges being measured  

• Preset parameters of quality control procedures  

• Compliance with federal, state and local governmental agencies  

As a general guideline, once a year is considered acceptable in most manufacturing and laboratory practices, but each organization must set its own policies.

Barnstead/ERTCO Thermometers