Deadweight Tester / Pressure Balance
Model LR-Cal LDW-H
Hydraulic, max. 1400 bar (20000 psi)
Deadweight Tester (Pressure Balance, Primary Standard for Pressure), single-piston and double-piston versions, hydraulic, pressure ranges from 1...120 bar to 1...1,400 bar and 10...1,600 psi to 10...20,000 psi.
Accuracy (measurement uncertainty) to ±0.006% or to ±0.015% of measured value.
Applications:
- Primary standard for defining the pressure scale in a range up to 1,400 bar hydraulic
- Reference instrument for calibration laboratories and factory for the testing, adjustment and calibration of pressure measuring instruments
- Complete, stand-alone system, also suitable for on-site use
Special features:
- Total measurement uncertainty to 0.006% of measured value
- Dual-range piston-cylinder system with fully automated changing between ranges
- Factory calibration includes traceability to national standars, as standard. Optional with UKAS or DKD/DAkkS calibration
- High long-term stability with recommended recalibration cycle every 5 years
- Fast and safe replacement of the piston-cylinder system via quick-release system as an option
Description
LR-Cal LDW-H Description
Proven primary pressure standard
Deadweight Tester / Pressure Balances are the most accurate instrument 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 enable a very small measurement uncertainty, in conjunction with an excellent long-term stability of 5 years (recommended in accordance with German Calibration Service DKD/DAkkS).
The deadweight tester / pressure balance has therefore been used for years in factory and calibration laboratories in national institutes, research laboratories and in industry.
Stand-alone operation
Due to its integrated pressure generation and the pure mechanical measuring principle, the model LR-Cal LDW-H is ideal for on-site use for maintenance and service.
Basic principle
Pressure is defined as the quotient of force and area. The core component of the model LR-Cal LDW-H is therefore a very pecisely manufatured piston-cylinder-system, which is loaded with masses in order to generate the individual test points.
The masses applied are proportional to the target pressure and this is achieved through optimally graduated weights. As standard, these masses are manufactured to the standard gravity (9.80665 m/s²), though the can be manufactured to a specific location (gravity) and also DAkkS-calibrated.
Easy operation
In the stable instrument base, the integrated priming pump and the 250 ml tank enable large test volumes to be easily filled and pressurised. For further pressure increases and find adjustment, a very precisely-controllable spindle pump is fitted, which only runs within the pump body.
As soon as the measuring system reaches equilibrium, there is a balance of forces between the pressure and the mass load applied. The excellent quality of the system ensures that this pressure remains stable over several minutes, so that the pressure value for comparative measurements can be read without any problems, or also so that more complex adjustments can be carried out on the item under test.
High-performance instrument range
The LR-Cal LDW-H instrument base is available in 2 variants:
- Standard hydraulic base
Up to max. 1,200 bar / 16,000 psi.
With integrated pressure generation through priming pump and spindle pump.
Standard pressure transmission medium: mineral oil. Optional: sebacate oil, brake fluid, Skydrol or Fomblin oil.
- Hydraulic high-pressure base
Up to max. 1,400 bar / 20,000 psi.
With integrated pressure generation through priming pump and spindle pump.
Pressure transmission medium: mineral oil or sebacate oil
As standard, both instruments bases are fitted with a connection for the piston-cylinder system with 3/4" BSP female thread.
With the 1,200 bar instrument base, a quick-release mechanism is available as an option. This enables the piston-cylinder system to be changed quickly and safely without any tools.
The connection of the test item is made without tools using a quick-connection. Via the freely-rotating knurled nut, the test item can be oriented as required. As standard, a threaded insert with a 1/2" BSP female thread is provided. Other threaded inserts are available to connect the most common pressure measuring instruments.
Piston-cylinder system
LR-Cal LDW-H Piston-cylinder-system
The piston-cylinder systems for the deadweight tester / pressure balance LR-Cal LDW-H are available in two fundamentally different designs, depending on measuring range:
- Single piston-cylinder system
Type LR-Cal LDW-H-EKZ
for measuring ranges 120 bar and 300 bar - Double piston-cylinder system
Type LR-Cal LDW-H-DKZ
for all higher pressure ranges (700 bar, 1,200 bar and 1,400 bar)
High accuracy over a wide measuring range
The dual-range piston-cylinder system LR-Cal LDW-H-DKZ offers two measuring ranges in one housing with automatic measuring range switching from low-pressuzre to high-pressure pistons. This provices the user with an extremely flexible measuring instrument that can cover a wide measuring range with high accuracy, with only one piston-cylinder unit and one set of weights. Additionally two test points can automatically be achieved by the operator loading masses once.
The piston and cylinder are manufactured from hardened steel and tungsten carbide, respectively. This pairing of materials has very low pressure and temperature coefficients of expansion, which results in a very good linearity for the cross-sectional area and a very high accuracy.
Piston and cylinder are very well protected, against contact, impacts or contamination from outside, in a solid stainless-steel/hardened tool steel housing. At the same time, overpressure protection is integrated, which prevents the piston from being forced out vertically and avoids damage to the piston-cylinder system in the event of mass removal under pressure.
The masses are stacked directly onto the piston-cylinder shaft. This makes it easier for the operator to place the masses on and thus enables a lower start value.
The overall design of the piston-cylinder unit and the very precise manufacturing of both the piston and the cylinder, ensure exceptionally low friction force, which results in excellent operating characteristics with long free-rotation time and low sink rates. Thus a high long-term stability is unsured. Therefore the recommended recalibration interval is 5 years depending on the conditions of usage.
| LR-Cal LDW-H-EKZ Single piston-cylinder system for pressure ranges 120 bar and 300 bar |
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| LR-Cal LDW-H-DKZ Double piston-cylinder system for all higher pressure ranges |
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Specification
LR-Cal LDW-H Specification set of masses
The standard mass set is supplied in a wooden case with a foam insert. This includes the masses listed in the tables of masses in the datasheet (see DOWNLOADs), made from non-magnetic stainless steel, and optimised for everyday use. For finer increments and for a higher resolution, as an option, the standard mass sets can be extended by e set of fine increment weights LR-Cal LDW-H-FMS. If even smaller intermediate values need to be generated, using one of the class M1 or F1 trim-masses sets from the accessories is recommended.
Should you not operate the instrument under reference conditions (ambient temperature 20°C, air pressure 1,013 mbar, relative humidity 40%), the relevant corrections must be made.
The masses are manufactured, as standard, to the standard gravity (9.80665 m/s²) although they can be adjusted for any particular location.
The mass sets can be manufactured for the following different pressure units: bar, kg/cm², kPa, MPa or psi and can be used with the same piston-cylinder system.
LR-Cal LDW-H Specification Piston-cylinder-system
Single piston measuring ranges:
| Measuring Range 1) | bar, kg/cm² | 1...120 | 2...300 |
| Required masses | kg | 49.7 | 49.6 |
| Smallest step 2) standard set of masses | bar, kg/cm² | 0.5 | 2.5 |
| Smallest step 3) optional fine increment weights | bar, kg/cm² | 0.02 | 0.05 |
| Nominal cross-sectional area of the piston | cm² | 0.4032 | 0.1613 |
| Measuring Range 1) | psi, lb/in² | 10...1,600 | 30...4,000 |
| Required masses | kg | 45.5 | 45.3 |
| Smallest step 2) standard set of masses | psi, lb/in² | 5 | 20 |
| Smallest step 3) optional fine increment weights | psi, lb/in² | 0.2 | 0.5 |
| Nominal cross-sectional area of the piston | cm² | 0.4032 | 0.1613 |
| Measuring Range 1) | kPa | 100...12,000 | 200...30,000 |
| Required masses | kg | 49.7 | 49.6 |
| Smallest step 2) standard set of masses | kPa | 50 | 250 |
| Smallest step 3) optional fine increment weights | kPa | 2 | 5 |
| Nominal cross-sectional area of the piston | cm² | 0.4032 | 0.1613 |
| Accuracy | |||
| Standard 4) 5) | % of measured value |
0.015 | 0.015 |
| Optional 4) 5) | % of measured value |
0.007 | 0.006 |
| Pressure transmission medium | |||
| Standard | Hydraulic fluid based on mineral oil | ||
| Optional |
Sebacate oil |
||
| Material | |||
| Piston | Steel | Steel | |
| Cylinder | Bronze | Steel | |
| Set of masses | Stainless steel, non-magnetic | ||
| Weights | |||
| Piston-cylinder system | kg | 1 | 0.8 |
| Storage case for piston-cylinder system | kg | 3.1 | 3.1 |
| "bar" standard mass sets (in 2 wooden cases) | kg | 61.3 | 61.2 |
| "psi" standard mass sets (in 2 wooden cases) | kg | 57.1 | 56.9 |
| Optional "bar" fine increment masses | kg | 0.33 | 0.5 |
| Optional "psi" fine increment masses | kg | 0.23 | 0.34 |
| Dimensions | |||
| Carrying case for standard mass sets | mm | W 400 x D 310 x H 310 | |
| Optional storage case for piston-cylinder systems | mm | W 300 x D 265 x H 205 | |
Double piston measuring ranges:
| Measuring Range 1) | bar, kg/cm² | 1...60 / 10...700 |
1...60 / 20...1.200 |
1...60 / 20...1.400 |
| Required masses | kg | 57.4 | 49.2 | 57.4 |
| Smallest step 2) standard set of masses | bar, kg/cm² | 0.5 / 5.0 | 0.5 / 10 | 0.5 / 10 |
| Smallest step 3) optional fine increment masses | bar, kg/cm² | 0.01 / 0.1 | 0.01 / 0.2 | 0.01 / 0.2 |
| Nominal cross-sectional area of the piston | cm² | 0.8065 / 0.0807 | 0.8065 / 0.0403 | 0.8065 / 0.0403 |
| Measuring Range 1) | psi, lb/in² | 10...800 / 100...10,000 | 10...800 / 200...16,000 | 10...800 / 200...20,000 |
| Required masses | kg | 56.4 | 45 | 56.4 |
| Smallest step 2) standard set of masses | psi, lb/in² | 5 / 50 | 5 / 100 | 5 / 100 |
| Smallest step 3) optional fine increment masses | psi, lb/in² | 0.1 / 1 | 0.1 / 2 | 0.1 / 2 |
| Nominal cross-sectional area of the piston | cm² | 0.8065 / 0.0807 | 0.8065 / 0.0403 | 9.8065 / 0.0403 |
| Measuring Range 1) | kPa | 100...6,000 / 1,000...70,000 | 100...6,000 / 2,000...120,000 | 100...6,000 / 2,000...140,000 |
| Required masses | kg | 57.4 | 49.2 | 57.4 |
| Smallest step 2) standard set of masses | kPa | 50 / 500 | 50 / 1,000 | 50 / 1,000 |
| Smallest step 3) optional fine increment masses | kPa | 1 / 10 | 1 / 20 | 1 / 20 |
| Nominal cross-sectional area of the piston | cm² | 0.8065 / 0.0807 | 0.8065 / 0.0403 | 0.8065 / 0.0403 |
| Accuracy | ||||
| Standard 4) 5) | % of measured value |
0.015 | 0.015 | 0.025 |
| Optional 4) 5) | % of measured value |
0.006 | 0.007 | 0.007 |
| Pressure transmission medium | ||||
| Standard | Hydraulic fluid based on mineral oil | |||
| Optional |
|
Sebacate oil Brake fluid Skydrol Fomblin oil |
Sebacate oil Brake fluid Skydrol Fomblin oil |
Sebacate oil |
| Material | ||||
| Piston | Tungsten carbide / steel | Tungsten carbide /steel | Tungsten carbide / steel | |
| Cylinder | Steel / Tungsten carbide | Steel / Tungsten carbide | Steel / tungsten carbide | |
| Set of masses | Stainless steel, non-magnetic | |||
| Weight | ||||
| Piston-cylinder system | kg | 2 | 2 | 2 |
| Storage case for piston-cylinder system (optional) | kg | 3,1 | 3,1 | 3,1 |
| "bar" standard set of masses (in 2 wooden cases) | kg | 69 | 60,8 | 69 |
| "psi" standard set of masses (in 2 wooden cases) | kg | 68 | 56,6 | 68 |
| Optional "bar" fine increment masses | kg | 0,5 | 0,5 | 0,5 |
| Optional "psi" fine increment masses | kg | 0,34 | 0,34 | 0,34 |
| Dimensions | ||||
| Carrying case for standard mass sets | mm | B400 x T310 x H310 | ||
| Optional storage case for piston-cylinder systems | mm | B300 x T265 x H205 | ||
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.
LR-Cal LDW-H Specification basement
| Base version | ||
| Hydraulic, standard, LR-Cal LDW-H-S | up to a max. 1,200 bar / 16,000 psi; with internal pressure generation | |
| Hydraulic, high-pressure, LR-Cal LDW-H-H | up to a max. 1,400 bar / 20,000 psi; with internal pressure generation | |
| Pressure transmission medium | ||
| Standard | Hydraulic fluid based on mineral oil | |
| Optional | Sebacate oil, Brake fluid, Skydrol or Fomblin oil (dependant upon measuring range) | |
| Fluid reservoir | cm³ | 250 |
| Connections | ||
| Connection for piston-cylinder system | 3/4" BSP male; optional: quick-release connector (not for 1,400 bar version) | |
| Test item connector | 1/2" BSP female quick connector as standard, freely rotating, changeable (for other threaded inserts, see accessories) |
|
| Material | ||
| Piping in instrument base | Stainless steel 1.4404, 6 x 2 mm | |
| Weight | ||
| Base"standard", LR-Cal LDW-H-S | kg | 18.0 (19.0 with optional quick-release connector) |
| Base "high-pressure", LR-Cal LDW-H-H | kg | 18.0 |
| Optional storage case for basement | kg | 8.5 |
| Permissible ambient conditions | ||
| Operating temperature | °C | 18...28 |
| Dimensions | ||
| Base (both versions) | mm | W 400 x D 375 x H 265 |
LR-Cal LDW-H Approvals + Certificates
- CE-Conformity:
Pressure equipment directive 97/23/EC (Module A) - Calibration:
factory certificate of calibration, traceable
Optional UKAS-/DAkkS-certification
LR-Cal LDW-H Scope of delivery + Options
Scope of delivery:
- Base with adjustable feet
- Priming pump
- Spindle pump for pressure generation and fine adjustment
- Piston connection with 3/4" BSP male thread
- Quick connector for test items with 1/2" BSP female threaded insert, changeable
- Piston-cylinder system
- Standard mass sets in carrying case
- Set of masses manufactured to standard gravity (9.80665 m/s²)
- Mineral oil bases hydraulic fluid (1.0 litre)
- Manual in Englisch and German language
- Factory calibration certificate, traceable to national standards
Options:
- Other pressure transmission media
- Piston connection with quick-release connector
- System with increased accuracy to 0.006%
- Other pressure units
- Set of masses manufactured to local gravity
- Fine increment weights
- Storage case for the base and the piston-cylinder system
- DAkkS or UKAS calibration certificate
Accessories
LR-Cal LDW-H Accessories
| Order-Code | Description | Image |
| LDW-FMS-F1 |
The weights included in the standard mass set or fine inrement weights are ideally suited for every day use. If smaller intermediate values need to be generated, we recommend using a set of trim masses. Trim mass set, class F1 |
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| LDW-FMS-M1 | Trim mas set, class M1 (1 x 50 g, 2 x 20 g, 1 x 10 g, 1 x 5 g, 2 x 2 g, 1 x 1 g, 1 x 500 mg, 2 x 200 mg, 1 x 100 mg, 1 x 50 mg, 2 x 20 mg, 1 x 10 mg, 1 x 5 mg, 2 x 2 mg, 1 x 1 mg |
|
| CPB5000-ADS | As a standard, the deadweight tester / pressure balance is equipped with a quick connector for connecting the test item. For this purpose, various threaded adapters, which can be easily changed, are available: Adapter set: 1/4" BSP, 3/8" BSP, 1/2" NPT and M20 x1.5 Additionally the sets of adapters include spare O-rings as well as a spanner with SW32 flats and SW14 flats, for changing the adapters. |  |
| CPB5000-ADS-NPT | Adapter set "NPT": 1/8" NPT, 1/4" NPT, 3/8" NPT and 1/2" NPT | |
| LDW-PAS-G12 | Test item connecting piece, 3/4" BSP female to 1/2" BSP female, free-rotating, operation as a comparison test pump is possible (---> base unit with 2 test item connectors) |  |
| CPB5000-WA90 | 90° angle connection, for test items with back mounting connection |  |
| CPB5000-TV-1000 | Separator (without diaphragm), max. 1,000 bar | |
| LDW-TV-M-0700 | Separator (to separate 2 liquid media by diaphragm), max. 700 bar |  |
| LDW-TV-M-1200 | Separator (to separate 2 liquid media by diaphragm), max. 1,200 bar |  |
| CPB5000-R-SET | O-ring set consisting of 5 pcs. 8 x 2 and 5 pcs. 4 x 2.2 (for piston connector and test item connector) |  |
| CPB5000-FLUID | Special operating fluid: hydraulic fluid based on mineral oil | |
| LDW-H-KA | Adapter for mounting piston-cylinder system into a quck-release mechanism | |
| LDW-PAS-G12-CT | Special test-item adapter with quick connect, for the matching to the quick-release system, operation as a comparison test pump possible | |
| LDW-H-E-230 | Motorised piston drive unit for 700 bar, 1,200 bar and 1,400 bar measuring ranges (115...230 VAC, 50/60 Hz) |  |
DOWNLOADs
LR-Cal LDW-H Datasheet / Operating manual
Datasheet LR-Cal LDW-H
Manual LR-Cal LDW-HExcel Sheet
MS Excel sheet to calculate corrections (air density, piston temperature, local gravity) and masses/pressure calculations.
