LR-Cal LDW-H Hydraulic deadweight tester/pressure balance

Description of LR-Cal LDW-H

Proven primary standard

Pressure balances (deadweight tester) are the most accurate devices available on the market for the calibration of electronic or mechanical pressure measuring instruments. The direct measurement of the pressure (p = F/A), as well as the use of high quality materials allow a very small measurement uncertainty in combination with an excellent long-term stability of 5 years (recommendation according to the German Calibration Service (DAkkS). Pressure balances / deadweight tester have been used for years in factory and calibration laboratories of industry, national institutes and research institutes.

Autonomous mode of operation

Due to the integrated pressure generation as well as the purely mechanical measuring principle, the LR-Cal LDW-H deadweight tester is also ideally suited for on-site use, maintenance and service.

Basic principle

Pressure is defined as the quotient of force and area. Accordingly, the heart of the LR-Cal LDW-H pressure balance is a very precisely manufactured piston/cylinder system, which is loaded with mass supports to generate the individual test points.

The mass support is proportional to the target pressure and is achieved by optimally graduated disc weights. These disc weights are manufactured as standard to the standard acceleration of gravity of 9.80665 m/s², but can also be optionally adapted to their specific location of use and also DAkkS-calibrated.

Simple mode of operation

In the sturdy basic unit, even large test volumes can be easily filled and compressed with the integrated pre-pressure pump and 250 ml tank. For further pressure build-up, a very precisely adjustable spindle pump with internal rotating spindle is installed.

As soon as the measuring system is in a floating state, there is a balance of forces between the pressure and the mass supports. Due to the excellent workmanship of the system, this pressure remains stable for several minutes, so that the pressure values for comparative measurement or even more extensive adjustment work can be carried out on the test specimen without any problems.

Two basic unit versions

The LR-Cal LDW-H deadweight tester is available in two versions, both with integrated pressure supply:

• Basic unit, hydraulic – “Standard
  Type LR-Cal LDW-H-S
  up to max. 1,200 bar (16,000 psi)
  Pressure transmission media: mineral oil, optional: sebacate oil, brake fluid, Skydrol or Fomblin oil
• Basic unit, hydraulic – “high pressure
  Type LR-Cal LDW-H
  up to max. 1,400 bar (20,000 psi)
  Pressure transmission media: mineral oil, optional: sebacate oil
  Standardmäßig sind beide Grundgeräte-Ausführungen mit einem Anschluss für das Kolbenzylindersystem mit Außengewinde G 3/4 ausgerüstet. Beim Grundgerät Ausführung “Standard” ist optional eine Schnellspannaufnahme für das Kolbenzylindersystem erhältlich. Diese ermöglicht einen schnellen und sicheren Wechsel des Kolbenzylindersystems ohne Werkzeug.

The test specimen is connected to a quick-connect system without tools. Due to the free-running knurled nut, the test specimens can be aligned as required. A threaded insert with a 1/2″ BSP female thread is included as standard. Further threaded inserts are optionally available, with which all common pressure gauges can be connected.

Special features:

• Total measurement uncertainty up to ±0.006% 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
• Stainless steel mass disks, optional adaptation to local gravitational acceleration of the application site
• Compact dimensions

Applications:

• Primary standard for the measurand pressure, up to max. 1,400 bar (20,000 psi), hydraulic
• 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.

Technical specifications of LR-Cal LDW-H

Single piston pressure ranges:

Double piston pressure ranges:

1) Theoretical starting value; corresponds to the pressure value generated by the piston or the piston and its make-up weights (bei their own weight). To optimise the operating characteristics more weights should be loaded.

2) The smallest pressure change value that can be achieved based on the standard weight set. To reduce this, a set of trim masses is also available. See Accessories.

3) The smallest pressure change value that can be achieved based on the optional fine increment weights. For further reductions, an accessory of class M1 or F1 trimm masses is available.

4) The accuracy from 10% of the measuring range is based on the measured value. In the lower range, the accuracy is 0.03% of reading for single-range piston-cylinder-systems and 0.025% of reading for dual-range piston-cylinder-systems.

5) Measuring uncertainty assuming reference conditions (ambient temperature 20°C, air pressure 1,013 mbar, relative humidity 40%).Corrections mus be made if required.

Accessories for

Photo	Model	Description
	LDW-H-KOFFER-KZS	Transport and storage case for the piston cylinder system
	LDW-FMS-F1	Fine incremental weight set class F1 1 mg bis 50 g
	LDW-FMS-M1	Fine incremental weight set class M1 1 mg bis 50 g
	LDW-ADAPTER-BSP	Set of BSP adapter for test item port to 1/2" + 1/4" + 3/8" + 1/2" BSP
	LDW-ADAPTER-NPT	Set of NPT adapter for test item port to 1/8" + 1/4" + 3/8" + 1/2" NPT
	CPB5000-WA90	90° elbow connector e.g. for connecting pressure gauges with rear pressure connection to the test connection of the deviceLDW-TV-M-1200
	LDW-TV-M-0700	Separator max. 700 bar with membrane. To separate the media of the test specimen and the device
	LDW-TV-M-1200	Separator max. 1,200 bar with membrane To separate the media of the test specimen and the device