LR-Cal LDW-P deadweight tester / pressure balance
pneumatic, up to 120 bar
Accuracy up to ±0.008% of measured value

LR-Cal LDW-P description

Special features:

• Total measurement uncertainty up to ±0.008% of measured value
• With traceable factory calibration certificate as standard (option: DAkkS calibration certificate)
• Very high long-term stability, recommended recalibration only every 5 years
• Mass disks made of stainless steel, adaptation to local gravitational acceleration of the place of use without extra charge
• Compact dimensions

Applications:

• Primary standard for the measurand pressure, up to max. 120 bar (1,600 psi), pneumatic
• Reference instrument for factory and calibration laboratories for testing, adjusting and calibrating pressure measuring instruments of all types
• Self-sufficient complete system, also suitable for on-site use.

LR-Cal LDW-P piston cylinder system

The pistons and cylinders are made of tungsten carbide. Tungsten carbide has very low coefficients of pressure and temperature expansion compared to other materials, which results in very good linearity of the effective piston cross-sectional area and high accuracy.

Piston and cylinder are very well protected in a solid stainless steel housing against contact, impact or contamination from the outside. At the same time, an overpressure safety device is integrated, which prevents the piston from being pushed out vertically and thus prevents damage to the piston-cylinder system in the event of disk weights being removed under pressure.

The disc weights are stacked on a bell that is placed on the skirt of the piston. The design of the bell ensures a very low center of gravity for the weights placed on top, which minimizes the lateral forces on the piston-cylinder system and friction. For lower starting pressures, a lighter aluminum plate can also be used instead of the bell.

The overall design of the piston-cylinder unit and the precise manufacture of the piston and cylinder ensure extremely low frictional forces, which result in excellent running properties with a high free rotation time and low sink rates. This ensures very high long-term stability. The recommended recalibration cycle is therefore five years depending on the conditions of use.

The connection of the piston-cylinder system is an M30 x 2 external thread as standard. Optionally, a quick-release fastener is available for easy piston (= measuring range) change without tools.

LR-Cal LDW-P specification

LR-Cal LDW-P pressure ranges

Vacuum ranges -1...-0,015 bar and -15...-0,2 PSI are realised with a vacuum adapter. This vacuum ranges are possible with basement version with port for external pressure/vacuum source only. Also a suitable vacuum pump is required.

1) Theorethical starting value. Corresponds to the pressure value generated by the piston or the piston and its make-up weight (by their own weight). To optimize the operating characteristics more masses should be loaded.

2) The smallest pressure range value that can be achieved based on the standard mass set.

3) The smallest pressure change value that can be achieved based on the optional set of fine increment masses, order-code LDW-P-FMS. For further reductions, an accessory of class M1 (order-code LDW-FMS-M1) or class F1 (order-code LDW-FMS-F1) is available.

4) The accuracy is in reference to the measured value, from 10% of the measuring range to compensate for actual area of piston unit. Standard accuracy without any corrections for the actual area down to 0.02% (0.03% of reading below 10% of range). For the range 0.015...1 bar the accuracy below 10% of the range is 0.04% of reading.

LR-Cal LDW-P scope of standard supply

• Instrument base LR-Cal LDW-P
• Priming pump (only at pressure ranges up to 7 bar / 100 psi
• Connection for external pressure supply (only with vacuum and from 25 bar)
• Only vacuum: vacuum adapter
• Spindle pump (pressure generation and fine adjustment)
• Piston mount with male thread M30 x 2
• Quick connector for test specimen, with threaded insert 1/2" BSP female thread, exchangeable
• Piston cylinder system
• Standard set of dimensions in carrying case, manufactured to normal acceleration due to gravity 9.80665 m/s².
• Inspection certificate 3.1 according to DIN EN 10204
• Operating manual DE+EN