LR-Cal LDW-H User manual

Operating Instructions
Betriebsanleitung
LR-Cal LDW-H
Deadweight Tester /Pressure Balance GB
Deadweight Tester / Pressure Balance LR-Cal LDW-H
Druckwaage /Kolbenmanometer D

Deadweight Tester /PressureBalanceGB
LR-CalLDW-H
Operating InstructionsLR-CalLDW-H
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Information
Thissymbol provides y o u withinformation, notes and tips.
Warning!
Thissymbol warns you against actions that can cause injury to people or
damage to the instrument.
Operating Instructions LR-Cal LDW-HPage 4 -36GB
Betriebsanleitung LR-Cal LDW-H Seite 37 -71D

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Contents
1. General ................................................................................................... 5
1.1 General Instructions ............................................................................................................................... 5
1.2 Safety Instructions ..................................................................................................................... 6
2. Product Description ................................................................................................... 7
2.1 General Product Information ................................................................................................................ 7
2.2 Basic principle of the Pressure Balance ........................................................................................... 8
2.3 Environmental factors ............................................................................................................................ 9
2.3.1 Local fluctuations in gravity-value ........................................................................................ 9
2.3.2 Temperature (Piston/Cylinder) ....................................................................................................... 10
2.3.3 Ambient conditions ........................................................................................................................... 10
2.3.4 How the cross-sectional area responds to pressure ............................................................... 11
2.4 Arrangement of control elements ..................................................................................................... 11
2.4.1 Standard hydraulic base .................................................................................................................. 12
2.4.2 High-pressure hydraulic base ........................................................................................................ 13
3. Commissioning and Operation ................................................................................................. 14
3.1 Preparation .............................................................................................................................................. 14
3.1.1 Setting up the Device ........................................................................................................................ 14
3.1.2 Hydraulic pressure mediums used ............................................................................................... 14
3.1.3 Installing the piston-cylinder system ........................................................................................... 15
3.1.3.1 Connection for piston-cylinder system wit h G3/4 B(male) thread ................................... 16
3.1.3.2 Connection for piston-cylinder system wit h optional quick connector .......................... 17
3.1.3 Connecting the device under test ................................................................................................. 18
3.1.4 Venting the System ............................................................................................................... 18
3.2 Operation ............................................................................................................................................... 19
3.2.1 Procedure for single-range piston-cylinder system 1,600 psi or 120 bar ....................... 19
3.2.1.1 Mass loading .................................................................................................................................... 19
3.2.1.2 Approaching the pressure value ...................................................................................... 19
3.2.1.3 Pressure stable ............................................................................................................................... 19
3.2.2 Procedure for single-range piston-cylinder system 4,000 psi or 300 bar ....................... 20
3.2.2.1 Mass load ............................................................................................................................ 20
3.2.2.2 Approaching the pressure value ...................................................................................... 20
3.2.2.3 Pressure stable ............................................................................................................................... 20
3.2.3 Procedure for all dual-range piston-cylinder systems ............................................................ 21
3.2.3.1 Mass load ............................................................................................................................ 21
3.2.3.2 Approaching the pressure value ...................................................................................... 21
3.2.3.3 Pressure stable ............................................................................................................................... 21
3.2.4 Next pressure level ............................................................................................................................ 22
3.2.5 Releasing pressure ............................................................................................................... 22
3.3 Disassembly ........................................................................................................................................... 23
4. Troubleshooting measures ................................................................................................. 24
5. Maintenance and Care ................................................................................................. 25
5.1 Cleaning .................................................................................................................................... 25
5.1.1 Piston-cylinder system ......................................................................................................... 25
5.1.1.1 Procedure for single-range piston-cylinder system 1,600 psi or 120 bar .................... 26
5.1.1.2 Procedure for single-range piston-cylinder system 4,000 psi or 300 bar .................... 27
5.1.1.3 Procedure for all dual-range piston-cylinder systems ......................................................... 28
5.1.2 Weight Set ............................................................................................................................................ 29
5.2 Consumable Parts ................................................................................................................................. 29

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5.3 Changing the hydraulic pressure medium ............................................................................ 29
5.3.1 Removing hydraulic pressure medium ........................................................................................ 29
5.3.2 Filling in of hydraulic pressure medium ............................................................................. 29
5.3.3 Venting of the System (after Complete Filling only) ................................................................. 30
5.4 Recalibration .......................................................................................................................................... 30
6. Specifications ................................................................................................. 31
7. Tables of masses ................................................................................................. 34
8. Accessories ................................................................................................................................ 36

Deadweight Tester /PressureBalanceGB
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1. General .
1.1 General Instructions .
In the following chapters detailed information on the LR-Cal LDW-H pressure balance (deadweight
tester) and its proper use can be found.
Should y o u require further information, or should there be problems wh ic h are not dealt within detail in
the operating instructions, please contact the address below:
DRUCK & TEMPERATUR Leitenberger GmbH
Bahnhofstr. 33
D-72138 Kirchentellinsfurt
Tel: +49- (0) 7121 –909 20-0
Fax: [phone]
E-Mail: [e-mail]
www.lr-cal.net
If nothing to the contrary is agreed, the pressure balance is calibrated in compliance with the currently
valid body of international regulations and can be referred directly to a national standard.
The warranty period for the pressure balance is 24 months according to the general terms of supply of
ZVEI.
The guarantee is void if the appliance is put to improper use or if the operating instructions are not
observed or if an attempt is madeto open the appliance or to release attachment parts or the tubing.
Wealso point out that the content of these operating instructions neither forms part of an earlier or
existing agreement, assurance or legal relationship nor is meant to change these. All obligations of
DRUCK &TEMPERATUR Leitenberger GmbH result from the respective sales contract and the
general business terms o f DRUCK &TEMPERATUR Leitenberger GmbH.
LR-Cal is atrade markDRUCK &TEMPERATUR Leitenberger GmbH.
Names of companies or products mentioned in this handbook are registered trade
marksof the manufacturer.
The devices described in this manual represent the latest state of the art in terms of theirdesign,
dimension and materials. Wereserve the right to makechanges to or replace materials without any
obligation to give immediate notification.
Duplication of this manual in whole or in part is prohibited.
©2015 Copyright DRUCK &TEMPERATUR Leitenberger GmbH. All rights reserved.

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1.2 Safety Instructions .
Read these operating instructions carefully prior to operating
the LR-Cal LDW-H deadweight tester. Its trouble-free operation and reliability
cannot be guaranteed unless thesafety advise given in this manual is followed
whenusing the device.
1. Thesystem mustonly be operated bytrained and authorised personnel who understand the
manual and can work according to it.
2. Trouble-free operation and reliability of the device can only be guaranteed so long as the
conditions stated under "Setting up the device" are taken into consideration.
3. TheLR-Cal LDW-H always has to be handled with the care required for any precision instrument
(protect from humidity, impacts and extreme temperatures). Thedevice, the piston-cylinder-system
and the mass-set mustbe handled with care (don't throw, hit, etc.) and protected from
contamination. By no meansapply any force to the operating elements of the LR-Cal LDW-H.
4. If the device is moved from acold to a warm environment, y o u should therefore ensure the device
temperature has adjusted to the ambient temperature before operational use.
5. If the equipment is damaged and operates no longer safely, then it should be taken out of service
and securely marked in such away so that it is not used until repaired.
Operator safety maybe at risk if:
There is visible damage to the device
The device is not working as specified
The device has been stored under unsuitable conditions for anextended period of time.
If there is any doubt, please return the device to the manufacturer for repair or servicing.
6. Customers mustnot attempt to alter or repair the device themselves. If the instrument is opened or
attachment parts or the tubing are released, its trouble-free operation and reliability is impaired and
mayendanger the operator. Please return the device to the manufacturer for any repair or
maintenance work.
7. Theremustbe used only the original sealings in the device.
8. Any procedure not included in the following instructions or outside of the manual mustnot be
attempted.

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2. Product Description .
2.1 General Product Information .
Application
Pressure balances are the mostaccurate instruments for the calibration of electronic or mechanical
pressure measuring instruments. The direct measurement of pressure, according to its definition as a
quotient of force and area, and the use of high-quality materials result in small uncertainties of
measurement and an excellent long-term stability of five years.
For these reasons pressure balances have already been used in calibration laboratories of industry,
national institutes and research labs for manyyears. Due to the integrated pressure generation and
the purely mechanical measuring principle the LR-Cal LDW-H is also ideally suitedfor on-site use as
well as service and maintenance purposes.
Piston-cylinder measuring system
Pressure is defined as a quotient of force and area. Correspondingly, the core of the LR-Cal LDW-H is
avery precisely manufactured piston/cylinder system. Thepiston and cylinder are manufactured from
hardened steel and tungsten carbide, respectively, and are very well protected in asolid stainless
steel/hardened tool steel housing against impacts or contamination from outside.
As a standard the connection of the piston-cylinder system is a G3/4 female thread. Aquick connector
is available as an option. This enables the piston-cylinder system to be changed quickly and safely
without any tools.
The piston-cylinder systemsof the LR-Cal LDW-H are available in two fundamentally different
designs, depending on measuring range.
■Single-range piston-cylindersystems (for measuring ranges 120 bar and 300 bar or 1,600 psi and
4,000 psi respectively), type LR-Cal LDW-H-EKZ.
■Dual-range piston-cylinder systems (for measuring ranges 700 bar, 1,200 bar and 1,400 bar or
10.000 psi, 16.000 psi und 20.000 psi respectively), typeLR-Cal LDW-H-DKZ.
The accuracy is 0.015 % as a standard (optional also to 0.008 or 0.006 %) of reading.
The dual-range piston-cylinder system offers two measuring ranges in one housing wit h automatic
measuring range switching from low-pressure to high-pressure pistons. This provides the user with an
extremely flexible measuring instrument that can coverawide measuring range wi th high accuracy,
with only one piston-cylinder unit and one set of weight s . Additionally two test points can automatically
be achieved bythe operator loading the masses only once (low pressure –high pressure area
utilisation).
The entire construction design of the piston-cylinder unit and the very precise manufacturing of the
piston and the cylinder stand for excellent operating characteristics with along free rotation time and
low fall rates and for avery high long term stability. Therefore the recommended re-calibration interval
is 5y e a r s depending on the conditions of usage.

Deadweight Tester /PressureBalanceGB
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Functioning
Depending on the measuring range of the device under test y o u can fit the instrument basement wi t h
the corresponding system.In order to generate the individual test points, the piston-cylinder system is
loaded with masses.Theweight applied is proportional to the desired pressure and provided by using
optimally graduated weights. These weights are manufactured to standard gravity (9.80665 m/s²)
although they canbe adjusted for customers specific location/gravity value.
The integrated priming pump and the 250 mltank enable large test volumes to be easily filled and
pressurised. For further pressure increases and fine adjustment, avery precisely-controllable spindle
pump is fitted, which is self-contained with in the pump body when in use.
As soon as the measuring systemreaches equilibrium, there is a balance of forces between the
pressure and massload applied.
The excellent quality of the systemensures 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 device under test.
dual-range piston-cylinder system
LR-Cal LDW-H-DKZ
Pressure p
Low-pressure piston
=High-pressure cylinder
single-range piston-cylinder system
LR-Cal LDW-H-EKZ
Pressure p
Force F
Cross-sectional
area A
High-pressure piston
Force F

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2.2 Basic principle of the Pressure Balance .
Their operating principle is based on the physical definition of pressure, the quotient of force and area.
Area
Force
essure Pr
Thekeyelement of the pressure balance is a precision-manufactured piston/cylinder system wi t h a
precisely measured cross-sectional area.
Toapply a pressure charge to the system, the piston is placed under a load with (calibrated) weig ht
pieces.
Each massfrom the set of weights is identified byanominal weight, whic h generates a pressure value
in the system (assuming standard reference conditions). Each weight has a number and in the
calibration certificate describing the massvalue to each weight with its resultant pressure value. The
weights are chosen according to the desired pressure value.
After that, the integrated spindle pump increases the pressure until the weights are in a floating state.
2.3 Environmental factors .
The piston pressure gauge is calibrated to standard reference conditions when it leaves the factory
(depending on customer specifications).
If there are significant deviations between the application conditions and the defined reference
conditions, appropriate corrections mustbe made.
Following are the mainfactors that enter into play and mustbe considered.
Y o u c a n download afree o f charge MS E x c e l sheet for making recommended correction
calculations: https://www.druck-temperatur.de/images/software/dwt-corrections.zip
2.3.1 Local fluctuations in gravity-value .
The local force of gravitation is subject to major fluctuations caused bygeographical variation.
The value maydiffer from o n e place on earth to another by as muchas 0.5 %. Since this value has a
direct effect on the measurement, it is essential that it be taken into consideration.
The weight pieces can even be adjusted during manufacturing to match the location where they will be
used. Another option, especially if the device will be used at multiple locations, is to perform a
calibration to the standard gravity,
"Standard-g = 9.80665 m/s
2".
Then acorrection mustbe performed for each measurement according to the formula below:
gdardS sitenApplicatiog
pressureTrue 

 tan valueNominal
Example:
Local gravity set during manufacturing: 9.806650 m/s2
Locale gravity at application site: 9.811053 m/s2
Nominal pressure: 100 bar
Truepressure:
barbar
gg
pp
dardS
Local 0449.100
80665.9 81105.9
100
tan
Nominal 
Without the correction, measurements would differ from the nominal applied pressure by 0.05%.

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2.3.2 Temperature (Piston/Cylinder) .
The effective cross-sectional area of the piston-cylinder system is influenced by temperature.
The effect depends on the material used and is described by the temperature coefficient (TK).
In the event of deviations from standard reference conditions (typically 20°C), the following formula
mustbe used to makeacorrection:
  
TKtt
pressureTrue
ferenceAppl 

Re
11
valueNominal
Example:
Reference temperature: 20°C
Temperature during use: 23°C
TK: 0.0022%
 
 
barbarpressureTrue 99340.99
2.2202311
100 5

 
Without the correction, measurements would differ from the nominal applied pressure by 0.007%.
2.3.3 Ambient conditions .
The effects of ambient conditions
air pressure
room temperature
relative humidity
should always be taken into consideration if the highest level of accuracy is required.
Fluctuations in ambient conditions change air density.
The air density affects the pressure through the buoyancy of the weights:







 densityWeight
densityAir
Weight 1weightNominal
The air density is typically1.2 kg/m3
The density of the weights (non-magnetic steel) is 7900 kg/m3
Afluctuation of 5% in the relative humidity causes an additional uncertainty in the measurement of
about 0.001%.