LR-Cal deadweight tester / pressure balances are compact and powerful primary standars with excellent running characteristics, based on the physical principle of Pressure = Force / Area.
The direct measurement of the pressure (p = F/A), as well as the use of high-quality materials enable this small measurement uncertainty, in conjunction with an excellent long-term stability (recommended cycle of 5 years in accordance with the German Calibration Service DKD/DAkkS).
Through the selection of a dual-range piston-cylinder system (hydraulic model LR-Cal LDW-H only) with automatic measuring range switching, this measurement uncertainty can be ensured, even with a single measuring system, over a large pressure range.
Mass pieces placed on the top of a piston-cylinder system are the source of a precisely defined force. By producing a certain pressure (counter pressure) inside the deadweight tester / pressure balance by using e.g. the integrated hand pump, an equilibrium is achieved. In the state of equilibrium the pressure is high enouph, that the mass pieces, incl. the free-running piston of the piston-cylinder system, are floating, which will lead to a very accurate pressure at the test port.
The resource needed in this case is a pressure supply, but only for pneumatic applications >10 bar or a vacuum source for negative pressure versions.
Benefit: Large measuring range coverage is possible, long recalibration intervals and stand-alone operation.
LR-CAL Deadweight Tester / Pressure Balances
hydraulic, compact design, operated with oil
Ranges from 1...120 bar to 10...1,200 bar
resp. from 10...1,600 psi to 100...16,000 psi
Accuracy ±0.025% of measured value
or ±0.05% of measured value
hydraulisch, several operating fluids,
Ranges from 1...120 bar to 1...1,400 bar
resp. from 10...1,600 psi to 10...20,000 psi
Accuracy up to ±0.006% of measured value
or up to ±0.015% of measured value
Ranges from 0.03...2 bar to 0.4...100 bar
resp. from 0.435...30 psi to 5.8...1,500 psi
Vaccum -0.03...-1 bar / -0.435...-14 psi
Accuracy ±0,008% of measured value
or ±0.015% of measured value
High-Pressure, hydraulic, oil operated
Ranges from 25...2,500 bar to 25...5,000 bar
resp. from 350...40,000 psi to 350...70,000 psi
Accuracy ±0.020% of measured value
or ±0.025% of measured value
Dual piston range 1...2,600 bar up to ±0.007% of m.v.
Why pressure calibration using a deadweight tester?
♦Deadweight tester are primary standard for pressure measurement.
♦ Deadweight tester are the most accurate instruments for pressure measurements with an excellent long term stability.
♦The long term stability is ensured, as the masses do not change their origial weight (except at mechanical damages).
♦The total uncertainty is calculated based on the measured value (and not of the full scale value). For this reason, with just one piston-cylinder-system a wide pressure range can be realised with same great measurement accuracy and uncertainty.
♦Another advantage is, that no power supply is needed. Deadweight testers are strictly mechanical systems.
♦ Pneumatic deadweight testers with ranges up to 10 bar & hydraulic dead Weight tester do not need any external pressure supply.