Realization of the unit of torque with torque standard machines
Torque standard machines are the primary national standards for the physical quantity of torque. The unit of torque - the Newtonmeter - is realized in these machines for static use with discrete values in the range from 1 mN·m up to 20 kN·m and in the future up to 1 MN·m.
The metrological foundations of the realization of the torque are investigated, new principles are developed and used in measuring devices.
Development and investigation of calibration machines operating with the comparison method
Two calibration machines (measuring ranges: 0,01 N·m to 20 N·m and 1 N·m to 2 kN·m) are in operation for investigating the influence of the measuring procedure on the uncertainty of measurements using the comparison method.
The application fields range from hand-operated torque tools to torque wrenches and torque transducers.
Traceable calibration of ergometer test stands
According to the Medical Devices Act, foot pedal ergometers are considered as "medical devices with a measurement function". The rotational power provided by the patient is measured as a product of momentary rotation speed and acting torque. The standard to which all calibrated ergometers are finally traced back is operated by the Working Group.
Comparison measurements / calibrations
Intercomparison measurements are carried out with transfer standards in the measuring range from 0,1 N·m up to 20 kN·m (in the extended range up to 50 kN·m). Reference standards from calibration laboratories are compared and their smallest uncertainties of measurement are defined. Reference torque wrenches as well as torque measuring instruments for controlling less accurate calibration facilities are calibrated.
Torque transfer standards and multicomponent transducers
Transfer standards with known metrological properties, especially concerning its short- and long-term stability, are used for the dissemination of the unit of torque; by the help of multicomponent transducers it is possible to measure in calibration machines acting mechanical disturbing components which could influence the calibration of torque transducers.
Co-operation in national and international standardization of calibration methods
The standardization is neccesary to guarantee the uniformity of the testing methods and the comparability and equivalence of measuring results obtained in different machines.
Co-operation in the German Calibration Service (DKD)
During the accreditation of calibration laboratories within the DKD expert opinion is given. Industrial enterprises and material testing institutions get consultation and support with measuring instrumentation within the working group "Torque" of the comittee "Mechanical quantities" of the German Calibration Service.
