Temperature measurements happen across all types of industries, be it process industry or manufacturing industry, aeronautical, pharmaceuticals, or any industry for that matter. Take Pharmaceuticals for example, the raw materials for a medicine are combined in right ratio, under the right temperature and humidity settings, and through the right process we end up with a medicine. During the process, say if the temperature was off by a degree Celsius or two, seemingly a small error in the temperature setting could result in a harmful product that may very well not be a medicine. And hence the importance of temperature calibrators.
Basics of Temperature calibration
Temperature calibration is done to determine if the temperature measuring devices used in a process are showing accurate readings. The calibration is done in an environment with stable temperature and bringing in the temperature measuring device that is under test to see if it showing correct readings. The readings are compared against a calibrated measuring device that is also placed within the test environment. Hence for a successful calibration of a temperature device, all you need is a stable temperature source, a calibrated measuring device and the device under test (DUT). The temperature source is of two types, an electrically simulated source or a physical source of heat. Dry block calibrators are to do with calibrations done in a larger scale using the physical source of heat like a dry well or a temperature bath.
Dry block temperature calibrators
Dry block temperature calibrators, also called as dry well calibrators, come with metal inserts that have holes drilled in them for inserting temperature sensors. These holes are of different sizes and the metal insert can be removed outside as well. In this setup, the temperature sensors are in close proximity with the metal which is in close proximity with the temperature source. These calibrators provide very accurate and reliable results and most preferred for temperature calibrations.
Nagman has a wide range of high quality dry block temperature calibrators that can be used in various situations or needs like low temperature, medium temperature, high and very high temperature. There are also dual dry block calibrators available that is equipped to calibrate instruments for both lower and higher temperature levels.
Calibration using Temperature baths
Temperature baths are a temperature source that uses stirred liquid to maintain a stable temperature for calibrations. Temperature baths are known to provide an excellent thermal contact, stability and uniformity which is very important for a temperature sensor calibration. Due to their size, they can be used to calibrate in larger batches compared to a dry block calibrator. The baths are of various sizes from a standard temperature bath to micro baths. They can be both stationary as well as portable depending on the tank size. Nagman also hosts some great calibrators that uses oil bath and liquid bath.
Factors to consider before choosing a temperature calibrator
- The temperature range- This is the best place to start when you want to decide the type of calibrator to go for. What is the temperature range of the device that is under test? You can only choose the calibrator that cover the required temperature range.
- The batch size- how many temperature sensors need to be calibrated at a time? It is but commonsense to use temperature baths for larger batches. But if you need to calibrate small batch of temperature sensors, you can go with dry well calibrator.
- Type of sensor- Depending of the size, shape and type of sensor, you can choose the right kind of calibrator. Usually thermocouples and straight probes can be calibrated using dry block calibrator. For tougher shapes and sizes of temperature sensors, it is better to go for baths.
- Location of calibration- Another important factor to consider for choosing a calibrator. For calibration in sites or field, dry block calibrators and portable baths can be used because they are portable and heavy duty. In case of calibration in labs, larger temperature baths can be used.
- Level of accuracy required- Of course calibration in itself is done to determine the accuracy of a temperature device. However, during calibration, the highest level of accuracy required can be decided before choosing a calibration device. For very high accuracy, temperature baths work well but dry block calibrators provide adequate accuracy required for most applications.
Features of dry block temperature calibrators
- Dry block calibrators can be used to calibrate temperature devices with really wide range of temperature. There are calibrators that can be used for -40 deg Celsius to 100 deg Celsius or more. You can also find Dual dry block calibrators that can calibrate temperature range of -100 deg Celsius to 350 deg Celsius.
- In a dry block calibrator, anywhere between 10 to 40 sensors can be calibrated at a time. However, over loading if the sensors in a dry block is not recommended. Even so, if not for a dry block calibrator not more than 2- 3 sensors can be calibrated at a time.
- Dry block calibrators are also very heavy duty portable, bench top models that can be used for rugged field calibrations as well as in house calibrations. It is always safe to have a model of calibrator that can be carried out into the site for quick calibrations in the site.
- Since they are portable, dry block temperature calibrators come with digital displays which means that the results are highly accurate and reliable. This accuracy level can also be increased using an external reference called platinum resistance thermometer (PRT).