Dead Weight Tester Available from Vacuum upto 5000 bar Accuracy upto +/- 5000 bar / 70000 pai 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. Operating principle 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.