Temperature is the most commonly measured parameter in most applications. Measuring temperature involves using equipment like data loggers, thermocouples or other simpler thermometers. The ideal solutions for calibrating temperature sensors, depends on the type of sensor.
Generally, there are two types of instrument calibration equipment for temperature sensors: Dry Block and Liquid baths. They are both used in combination with a temperature reference sensor (Ellab Temperature Standard) to provide a stable temperature environment for comparison and defining accuracy. The different advantages and disadvantages for each instrument calibration method, depends on the type of temperature sensor being calibrated.
Dry Block - for shorter calibration cycles
Dry block calibration is easy to handle and works by heating and cooling the block to the required temperature. Dry Blocks typically have shorter calibration cycles, as the heating and cooling process is faster when dealing with heated/cooled air. This method is therefore ideal for quicker processes and faster temperature changes, all while offering a compact and fully mobile working station. As there are no liquids involved, there is no risk of spillage or fire hazards, which is a great advantage when choosing Dry Blocks as your calibration solution. Dry Blocks are especially ideal for long and straightened sensors, and have a temperature range of -100°C to +700°C.
Liquid Baths – calibration for all types of sensors
Liquid baths provide a highly stable environment in the calibration zone and offers a high precision due to the liquid media surrounding the sensors. Temperature baths can be used for all types of sensors, including short and bent sensors. Its flexibility when calibrating sensors, regardless of the shape, is one of the advantages when choosing Liquid Baths as your calibration solution. For optimal use, the liquid needs to be replaced regularly (depending on usage) and quality liquids should be chosen, in order to achieve homogeneity and stability within the calibration zone. The Liquid Baths have a temperature range between 80°C and 300°C.
Pressure instrument calibration
Pressure measurements are also frequently used in various applications, which makes pressure calibration important. If pressure calibrations are required for your process, please have a look at our pressure calibration solution.
Why instrument calibration is important
Calibration is a comparison between two devices, where one device is the instrument that requires calibration and the other is the reference sensor that defines the accuracy. Instrument calibrations are performed to ensure the accuracy of measuring devices, such as thermocouples and/or wireless data loggers, by using a temperature reference sensor, which is a pt100 reference instrument. Every measuring device drifts over time, due to normal wear and therefore require regular calibrations. RTD sensors are more stable than thermocouples and therefore tend to drift less, whereas thermocouples drift more over time. Regardless of drift tendencies, it is important that calibrations are performed to ensure a consistent quality of the manufactured products and confirm that the gathered data through e.g. validation activities, are reliable. When calibrating the sensors, their readings are compared with readings from the temperature reference sensor, while they remain in stable conditions within a liquid bath or dry block.
Necessity of regular calibration
The regularity of the required instrument calibrations depends on the application and environment, as harsher environments cause faster sensor drifts, than a milder environment would. Measuring accuracy also plays an important role when defining the necessity of a calibration. The more precise and specific the measuring parameter is, the more important it is to calibrate. Instrument calibration should always be a regular or planned part of the standard operational procedure (SOP), as it can have a crucial impact on the result if the sensor is not measuring correctly, even at very small deviations. In many manufacturing processes, a small temperature deviation percentage, will have serious consequences in the sterility and quality of the product, ultimately resulting in lost batches and wasted costs.
Even though instrument calibration can seem like a time-consuming part of the manufacturing process, it is important to note that the process cost and time can be reduced, as the result will be more precise and the process more efficient. Therefore, implementing some degree of instrument calibration is highly recommended in any process and industry.