This guidance is applicable to temperature sources that make use of solid blocks with regulated temperatures. Calibrators of this kind go by a variety of names, including dry-well calibrators, dry-block calibrators, and temperature-block calibrators, among others. Typically, they are made up of solid blocks of materials like metal or ceramic, a mechanism for controlling the temperature, a control sensor, and some kind of built-in indication of temperature that is contained inside portable packaging. When it comes to the calibration of industrial thermometers, dry-block calibrators are a typical tool of choice.
These calibrators are typically utilized in one of two modes: (1) the direct mode, in which the calibrator serves as the reference that is being calibrated, or (2) the comparison mode, in which the calibrator serves as an isothermal temperature source for comparing thermometers that are being tested to a separate reference thermometer that has been previously calibrated. The degree of inaccuracy associated with these calibrations is directly proportional to which of these two modes is used, in addition to a wide range of thermal parameters associated with the particular dry-block designs.
The degree of inaccuracy associated with these calibrations is directly proportional to which of these two modes is used, in addition to a wide range of thermal parameters associated with the particular dry-block designs.
It is possible, within the bounds of the measurement uncertainty, to create a temperature zone for calibration that is thermally homogeneous, stable, and accurate. It has been determined that various thermal properties of dry-block calibrator blocks need to be categorized and/or quantified in order to determine the unpredictability of measurements and the level of care that must be taken during the calibration process in order to optimize results in an appropriate manner.
Long ago, it was determined that temperature consistency was a characteristic that needed to be described. Axial temperature uniformity, radial temperature uniformity, stem conduction, block loading, hysteresis, and controller accuracy are some of the others. The surrounding temperature, drafts, and power fluctuations are all examples of external influences that might have an effect on the findings. The outcomes of the calibration will be much improved if these qualities are recognized and tested.
Scope
The values expressed using SI units are to be considered the standard and must be adhered to. This standard does not contain any additional units of measurement in its repertoire.
This standard does not claim to address all of the potential safety problems connected with its usage, even if there are any. Prior to using this standard, it is the duty of the user to establish adequate safety, health, and environmental procedures and to evaluate the application of regulatory limits.
This guide is designed for use with dry-block temperature calibrators without the use of fluids or thermal contact-enhancing substances throughout a temperature range of -100 °C to 1700 °C. It is intended for use with temperature calibrators that have a block that is completely dry.
This article provides a description of the fundamental characteristics of dry-block calibrators, which are instruments that are used for the purpose of performing thermometer calibration in either direct or comparative mode. In the comparative mode, an external sensor and an ancillary measurement are used as the reference, whereas in the direct mode, the dry-block calibrator is used as a standalone instrument, and the control sensor and the calibrator display serve as the reference. The direct mode is distinguished from the comparison mode by the term “direct mode.”
This handbook proposes measurement procedures that might maximize the accuracy of a dry-block calibrator in order to acquire the best possible results.
This guide proposes several tests that may be carried out in order to determine uncertainty limits and describes how such limitations can be used in the process of generating uncertainty budgets.
Accessories for dry-block calibrators that are not going to be covered in this section include things like built-in reference thermometers, switch testing circuits, computer communications, and current loops.
It is strongly recommended that liquid-in-glass thermometers not be used in dry-block calibrators. This is due to the fact that combining liquid-in-glass temperatures with a metal block may cause the reading of the thermometer to become corrupted.
Conclusion
In many cases, Dry block calibration can be of intense necessity. Proper instruments and measures should be used. Nagman provides the best Dry-block calibrators that are reliable and can be applied in all probable situations.
