Deadweight Tester / Pressure Balance
Model LR-Cal LDW-HK
Hydraulic, max. 1200 bar (16000 psi)
Deadweight Tester (Pressure Balance, Primary Standard for Pressure), hydraulic,
pressure ranges from 1...120 bar to 10...1,200 bar and 10...1,600 psi to 100...16,000 psi.
Accuracy (total uncertainty) ±0.05% or 0.025% of measured value.
Anwendungen:
- Primary standard for defining the pressure scale in a range up to 1,200 bar hydraulic
- Reference instrument for factory and calibration laboratiries 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 0.025% of measured value
- Factory calibration includes traceability to national standard; with UKAS calibration possible as an option
- High long-term stability with recommended recalibration cycle every five years
- Masses manufactured from stainless steel, can be adjusted to local gravity
- Compact dimensions
Description
LR-Cal LDW-HK 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-HK 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-HK 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 UKAS (DAkkS)-calibrated.
Easy operation
The integrated dual-area spindle pump enables rapid filling of the test system and smooth pressure generation up to 1,200 bar. At the same time, the precise adjustable spindle pump also serves for fine pressure adjustment. A control schematic for pressure generation on the instrument base facilitates quick and easy operation.
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.
Compact instrument design
The LR-Cal LDW-HK is also particularly notable for its compact dimensions, which are not altered during operation, since the spindle runs within the pump body.
With its compact dimensions, the exceptionally robust ABS plastic housing and the low weight associated with these, the LR-Cal LDW-HK is also particularly suited to on-site applications.
Piston-cylinder system
LR-Cal LDW-HK Piston-cylinder-system
The piston and cylinder of model LR-Cal LDW-HK Deadweight Tester / Pressure Balance are manufactured from tungsten carbide.
This pairing of materials, in comparison to other 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 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.
| LR-Cal LDW-HK piston-cylinder system with masses, without overhang (bell jar) |
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| LR-Cal LDW-HK piston-cylinder system with masses with overhang (bell jar) |
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The masses are stacked on an overhang (bell jar), which sits on the piston shaft. The construction of the overhang (bell jar) provides a very low centre of gravity for the stacked weights, which minimises both the side thrust on the piston-cylinder system and the friction. For smaller starting pressures, the masses can also be stacked directly onto the piston shaft, without using the overhang (bell jar).
The overall design of the piston-cylinder unit and the very precise manufacturing of both the piston and cylinder, ensures excellent operating characteristics with long free-rotation time and low sink rates.
Thus a high long-germ stability is ensured. Therefore the recommended recalibration interval is 5 years depending on the conditions of usage.
Set of masses
LR-Cal LDW-HK Set of masses
The following tables show, for the respective measuring range, the number of masses within a set of masses, with their resulting nominal pressures.
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.
| Measuring range [bar] |
1...120 Nominal pressure per pc. [bar] |
2,5...300 Nominal pressure per pc. [bar] |
5...700 Nominal pressure per pc. [bar] |
10...1200 Nominal pressure per pc. [bar] |
| Piston and make-up weight | 1 x 1 | 1 x 2.5 | 1 x 5 | 1 x 10 |
|
Piston, overhang (bell jar) |
1 x 20 | 1 x 50 | 1 x 100 | 1 x 200 |
| Masses stackable on overhang (bell jar) |
3 x 20 | 3 x 50 | 4 x 100 | 3 x 200 |
| Masses stackable on piston |
1 x 20 1 x 10 2 x 4 1 x 2 1 x 1 |
1 x 50 1 x 25 2 x 10 1 x 5 1 x 2.5 |
1 x 100 1 x 50 2 x 20 1 x 10 1 x 5 |
1 x 200 1 x 100 2 x 40 1 x 20 1 x 10 |
| Measuring range [psi] |
10...1600 Nominal pressure per pc. [psi] |
25...4000 Nominal pressure per pc. [psi] |
50...10000 Nominal pressure per pc. [psi] |
100...16000 Nominal pressure per pc. [psi] |
| Piston and make-up weight | 1 x 10 | 1 x 25 | 1 x 50 | 1 x 100 |
| Piston, overhang (bell jar) and overhang make-up weight |
1 x 190 | 1 x 475 | 1 x 950 | 1 x 1900 |
| Masses stackable on overhang (bell jar) |
5 x 200 | 5 x 500 | 7 x 1000 | 5 x 2000 |
| Masses stackable on piston |
1 x 200 1 x 100 2 x 40 1 x 20 1 x 10 |
1 x 500 1 x 250 2 x 100 1 x 50 1 x 25 |
1 x 1000 1 x 500 2 x 200 1 x 100 1 x 50 |
1 x 2000 1 x 1000 2 x 400 1 x 200 1 x 100 |
Specification
LR-Cal LDW-HK Specification piston-cylinder system
| Pressure range "bar" 1) | [bar] | 1...120 | 2.5...300 | 5...700 | 10...1,200 |
| Required masses | [kg] | 41 | 50 | 58 | 50 |
| Smallest step 2) standard mass set |
[bar] | 1 | 2,5 | 5 | 10 |
| Nominal cross-sectional area of the piston |
[in²] | 1/16 | 1/40 | 1/80 | 1/160 |
| Pressure range "psi" 1) | [psi] | 10...1,600 | 25...4,000 | 50...10,000 | 100...16,000 |
| Erforderliche Massen | [kg] | 38 | 47 | 58 | 47 |
| Smallest step 2) standard mass set |
[psi] | 10 | 25 | 50 | 100 |
| Nominal cross-sectional area of the piston |
[in²] | 1/16 | 1/40 | 1/80 | 1/160 |
| Accuracy | |||||
| Standard 3) | [% of measured value] |
0,05 | |||
| Option 3) | [% of measured value] |
0,025 | |||
| Pressure transmission medium | Hydraulic fluid based on VG22 mineral oil (0.5 l included in scope of delivery) | ||||
| Material | |||||
| Piston | Tungsten carbide | ||||
| Cylinder | Tungsten carbide | ||||
| Set of masses | Stainless steel, non-magnetic | ||||
| Weight | |||||
| Piston-cylinder system | [kg] | 2.4 | |||
| "bar"-mass set, incl. bell jar | [kg] | 41.5 | 50.5 | 58.5 | 50.5 |
| "psi"-mass set, incl. bell jar | [kg] | 47.5 | 47.5 | 58.5 | 47.5 |
| Optional carrying case for set of masses (2 pcs. required) |
[kg] | 5.8 | |||
| Dimensions | |||||
| Optional carrying case for set of masses (2 pcs. required) |
[mm] | W 400 x D 310 x H 310 | |||
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 accuracy from 10% of the measuring range is based on the measured value. In the lower range, a fixed error based on 10% of the range applies.
4) 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-HK Specification instrument base
| Connection for piston-cylinder system: | 3/4" BSP male | |
| Test item connection: | 1/2" BSP female thread, free-running, incl. adapter set to 1/4" BSP and 3/8" BSP female threads | |
| Wetted parts: | Austenitic stainless steel, high tensile brass, nitrile rubber | |
| Pressure transmission medium: | Hydraulic fluid based on VG22 mineral oil (0.5 l included in scope of delivery) | |
| Reservoir volume: | [cm³] | 170 |
| Weight instrument base: | [kg] | 13.5 |
| Weight optional storage case for the base: | [kg] | 8.5 |
| Permissible operating temperature: | [°C] | 18...28 |
| Dimensions of the base: | [mm] | W 401 x D 397 x H 155 |
LR-Cal LDW-HK Approvals + certificates
- CE-Conformity:
Pressure equipment directive 97/23/EC (Module A) - Factory certificate of calibration traceable to national standard
Optional UKAS (DAkkS) certification
LR-Cal LDW-HK Scope of delivery + Options
Scope of Delivery:
- Base, with adjustable feet
- Dual-area spindle pump for filling, pressure generation and fine adjustment
- Piston connection with 3/4" BSP male thread
- Test item connection with 1/2" BSP female thread, loose union connection
- Adapter set for test item connection, 1/2" BSP male to 1/4" BSP female and to 3/8" BSP female
- Piston-cylinder system with overhang (bell jar)
- Set of masses manufactured to standard gravity (9.80665 m/s²)
- Tool and maintenance set
- Manual in English and German language
- Factory calibration certificate, traceable to national standard
Options:
- System with increased accuracy to 0.025%
- Set of masses manufactured to local gravity
- Storage cases for the base, mass set and the piston-cylinder system
- UKAS calibration certificate
Accessories
LR-Cal LDW-HK Accessories
| Order-Code | Description | Image |
| LDW-FMS-F1 | The weights included in the standard mass set are ideally suited for everyday use. If smaller intermediate values need to be generated, we recommend using a set of trim masses. Set of trim masses, class F1 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, style="line-height: 1.3em;">2 x 20 mg, 1 x 10 mg, 1 x 5 mg, 2 x 2 mg, 1 x 1 mg> |
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| LDW-FMS-M1 | Set of trim masses, 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 |
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| LDW-HK-KOFFER-MS | Set of 2 carrying cases for set of masses | |
| LDW-HK-KOFFER-BM | Storage case for instrument base | |
| LDW-ADAPTER-BSP | "BSP" adapter set for 1/2" BSP male test item connector to 1/8" BSP, 1/4" BSP, 3/8" BSP and 1/2" BSP female |
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| LDW-ADAPTER-NPT | "NPT" adapter set for 1/2" BSP male test item connector to 1/8" NPT, 1/4" NPT, 3/8" NPT and 1/2" NPT female |
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| LDW-ADAPTER-M | "Metric" adapter set for 1/2" BSP male test item connector to M12 x 1.5 and M20 x 1.5 female |
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| LDW-PAS-G12 | Test item connection, 3/4" BSP female to 1/2" BSP female, loose union connection, to use the deadweight tester as pressure comparator with 2 test item connectors |
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| CPB5000-WA90 | 90° angle connection, for test items with back mounting connection |  |
| LDW-TV-M-0700 | Separator, to separate 2 liquid media by a diaphragm, max. 700 bar |  |
| LDW-TV-M-1200 | Separator, to separate 2 liquid media by a diaphragm, max. 1,200 bar |  |
| LDW-HK-R-SET | Sealing set for instrument base | |
| CPB5000-FLUID | Operating fluid (mineral oil based hydraulic oil, 1 litre) | |
| LDW-HK-W-SET | SPARE: tool set consists of open-ended spanner, BSP adapter, replacement seals, pointer removal device and pointer press-on tool |
DOWNLOADs
LR-Cal LDW-HK Datasheet / Operating manual
Excel Sheet
MS Excel sheet to calculate corrections (air density, piston temperature, local gravity) and masses/pressure calculations.
