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Hydraulic deadweight Tester for calibrating pressure measuring instruments
Deadweight testers are accepted as the most accurate method for the calibration of electronic or mechanical pressure measuring devices. LR-Cal LDW series of deadweight testers, which are available in the ranges from 10 bar up to 1400 bar.
The direct measurement of pressure (according to its definition as a quotient of force and area) ensures high accuracies and long term stability. These testers are used extensively in calibration laboratories in industry, standards institutes and research facilities.
The LR-Cal LDW series is ideally suited to on-site use as well as for service and maintenance purposes. The customised assembly allows the setup of a complete, compact system consisting of a universal basement and the measuring systems (piston/cylinder units). The high-quality piston/cylinder units are manufactured from tungsten carbide which is known for its small temperature co-efficiency. Fast and uncomplicated changes of the measuring range are possible using a flat spanner.
In order to generate the individual test points, the piston/cylinder system is weighted with mass loads which are also calibrated and specially adapted to the required application. The basement is fitted with the corresponding system, depending on the measuring range of the device under test. The pressure is set via an integrated pump or, if an external pressure supply is available, via control valves (pneumatic models).
For fine adjustment, an adjustable volume with a precision spindle is available. The weight applied is proportional to the desired pressure and provided by using optimally graduated weights. As soon as the measuring system reaches equilibrium, there is a balance of forces between pressure and wheel weights. Due to the excellent quality of the system, this pressure remains stable over several minutes, so that, for instance, adjustments of the device under test can be carried out without any problems.
For users who require a digital pressure display for connection to the Deadweight Tester, Instrotech can supply the Keller Leo2 that offers accuracies of 0.1%. An intrinsically safe version is available.