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

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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.

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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%.

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2.3.4 How the cross-sectional area responds to pressure .
At higher pressures, the effective cross-sectional surface changes due to the pressure load.
The ratio of the cross-section and prevailing pressure is linear within an initial approximation. It i s
represented by t h e coefficient o f expansion caused by pressure distortion ().
pressureNominal1 pressureNominal 


pressureTrue
Example:
Measuring point: 1000 bar
System with distortion coefficient: 10 –71/bar:
barbarpressureTrue 90.999
10001011 1000
7


Without the correction, measurements would differ from the nominal applied pressure by 0.01%.
2.4 Arrangement of control elements .
The LR-Cal LDW-H instrument bases are available in 2 variants:
Standard hydraulic base LR-Cal LDW-H-S
-up to max1,200 bar /16,000 psi
-with integrated pressure generation through priming pump and spindle pump
-tubing madeof stainless steel (1.4404), 6x2mm
-Standard pressure transmission medium: mineral oil
Optional: Sebacate oil, brake fluid, Skydrol or Fomblin oil
High-pressure hydraulic base LR-Cal LDW-H-H
-up to max1,400 bar /20,000 psi
-with integrated pressure generation through priming pump and spindle pump
-tubing madeof stainless steel (1.4404), 6x2mm
-Pressure transmission medium: mineral oil or Sebacate oil
As a standard both instruments bases are fitted with aconnection for the piston-cylinder system with
G3/4 B(male) thread.
The optional quick connector can be installed as an option allowing aquick and safe change of the
piston-cylinder system without the need for tools (not available for the hydraulic high-pressure
version!).
The connection of the test item is madewithout tools using a quick-connection. Via the freely-rotating
knurled nut, the test item can be oriented as required. As standard, athreaded insert with aG1/2
female thread is provided. Other threaded inserts are available to connect the mostcommon pressure
measuring instruments.

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2.4.1Standard hydraulic base LR-Cal LDW-H-S.
View from above
Front view
Rear view
Interface to the
external piston
temperature sensor
(Option on request!)
Connection for
test specimen
Initial pressure pump
Fixture for
piston/cylinder
system
(optional ConTect
quick connection)
Spirit
level
Screwpress
Outlet
valve
Rotating foot studs
for levelling base
Screwed drain plug
for tank

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2.4.2High-pressure hydraulic base LR-CalLDW-H-H.
View from above
Front view
Rear view
Interface to the
external piston
temperature sensor
(Option on request!)
Connection for
test specimen
Initial pressure pump
Fixture for piston-
cylinder system
G3/4 B(male)
thread
Spirit
level
Screwpress
Outlet
valve
Rotating foot studs
for levelling base
Screwed drain plug
for tank

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3. Commissioning and Operation .
3.1 Preparation .
3.1.1 Setting up the Device .
Set up the pressure balance on asolid surface. If it is not resting on a solid foundation or is
subject to vibrations, measurements and safety could be affected. This should be avoided.
If no temperature control system is present, the device should at least not be placed near aheat
element or window. This will reduce drafts and warm air flows as muchas possible.
The spirit level should be used to level the assembly. At this time, rough levelling can be performed
without the piston-cylinder system.Using the rotating foot studs, position the device so that it is
horizontal. For utmost accuracy, the spirit level should be put on top of the fitted piston and its level
adjusted to the horizontal.
Place the star handle with knobs onto the spindle pump. Ensure that the spring-loaded thrust pad
engages into the star handle bushing.
Werecommend unscrewing the spindle pump completely when y o u start to record measurement
values, (turning anticlockwise) to allow enough swept displacement for measurements. The outlet
valve mustbe opened during this process.
The oil container mayneed to be filled, or refilled (volume 250 ml).For this purpose, the locking
screw with the oil filling symbol on top of the basement mustbe opened. Special oil mustbe used
for refilling (1 litre supplied, or available as accessory). Thesystem mustbe vented before initial
filling, or after a complete oil change. For this purpose, please proceed according to section 5.3.3.
The protection film on the screwed drain plug of the oil container need to be removed before
operating (coverage of the ventilation hole during transportation).
3.1.2 Hydraulic pressure mediums used .
Mineral oil based hydraulic fluid
An hydraulic mineral oil with a viscosity grade VG22 is used as standard.
Certain customers maywish to use the piston unit on other hydraulic fluids. Before
attempting this, the following should be checked:
Pressure medium is compatible with bronze, hardened tool steel tungsten carbide and
with o-rings/composite seals used in the assembly. Special seal kits are available for
certain pressure mediums.
The new pressure medium being used will have inherent physical properties (density,
surface tension) that mayaffect the utmost accuracy of the unit. Units that havebeen
manufactured for a non-standard pressure medium wil l have had its calibrated mass
adjusted for the fluids buoyancy and surface tension components. If the piston unit
has not been specially calibrated, the accuracy of the unit will be reduced, and this
should be taken into account.

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Skydrol 500B
The instrument base is also available for use on Skydrol 500B or any other phosphate ester based fire
resistant liquid. This base is fitted with Ethylene Polypropylene (EP) seals. The operating
characteristics of the piston-cylinder system should be tested on Skydrol. EP seals are not suitable for
mineral oils.
Note that continual immersion of the instrument housing in Skydrol will cause
deterioration. Spillage should be wiped off the housing / cover immediately.
Brake fluids
The instrument base for use on non-petroleum based brake fluids should be ordered fitted with EP
seals and the operating characteristics of the piston-cylinder system should be tested on the liquid.
This liquid is known by the following names:
FMVSS No.116, DOT3 or DOT4, SAE J1703, BS AU 174:Part 2, IS04925.
Other fluids
The instrument base can be used on silicone based fluids, sebacate based fluids, or inert
perfluorinatedpolyethers such as Fluorolube, Fomblin, Halocarbon, whic h are of the viscosity as the
standard mineraloil based hydraulic fluid mentioned above and are chemically inert, being suitable for
contact with metals and with the nitrile seals which are standard on the base.
3.1.3Installing the piston-cylinder system .
The piston-cylinder systemthat is used depends on the device to be tested. You should select a
system with a comparable or higher measuring range.
The connection for the piston-cylinder system in the instrument base is available in 2different
versions:
-Connection for piston-cylinder system with G3/4 B(male) thread (see section 3.1.3.1)
-Connection for piston-cylinder system with optional quick connector, not for the 1,400 bar-version
(see section 3.1.3.2)

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3.1.3.1 Connection for piston-cylinder system with G3/4 B (male)thread .
Before removing the transit plug on the connector for the piston-cylinder
system, make sure the system is not under pressure (open the outlet valve).
The piston-cylinder systemis inserted vertically onto the thread of the piston receptacle, and
tightened byhand. Excess force is not required to achieve an effective seal. An O-ringseal is
already fitted, so no additional sealing material is required.
Ensure that the sealing surface of the piston-cylinder system is clean.
Check the o-ring in the piston stand is correctly seated and for any sign of wear.
Replace, if necessary.
For an exact alignment of the device, the spirit level may be removed from the base plate and
placed on the top of the fitted piston-cylinder system.This wi ll ensure the mostaccurate levelling of
the piston-cylinder system.
Oil collecting tray

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3.1.3.2Connection for piston-cylinder system with optional quick connector .
Before releasing the transit plug in the quick-release mechanism, make sure the
system is not under pressure (open the outlet valve).
Place the piston-cylinder system vertically in the quick connector.
Ensure that the sealing surface of the piston-cylinder system is clean.
Check the o-ring in the quick connector stand is correctly seated and for any
sign of wear. Replace, if necessary.
Turning the butterfly screw about one and ahalf turn clockwise (as far as it will go) is enough to
screw the system in place with an automatic seal (finger-tight).
For an exact alignment of the device, the spirit level may be removed from the base plate and
placed on the top of the fitted piston-cylinder system.This wi ll ensure the mostaccurate levelling of
the piston-cylinder system.
O-ring 4x2.2
(see accessories section 8.)
3.2.
1.
4. Put spirit level on
top of piston

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3.1.3 Connecting the device under test .
Place the device to be calibrated/verified in the quick connector with the knurled nut. It can be
freely positioned. Hand-tightening will suffice for effective sealing.
Tocalibrate instruments with rear/back entry connections, use the 90° angle connection (see
accessories section 8, order-code CPB5000-WA90).
Check the o-ring in the test stand is correctly seated and for any sign of wear.
Replace, if necessary.
Please see to it, that each instrument mounted to the pressure balance must be
clean inside.
The quick connector comes equipped with a G1/2 threaded insert in the standard delivery
package.
Wheny o u are calibrating devices wit h different connection threads, the threaded
inserts can be changed as appropriate (see accessories "Adapter Set"). For short
connection threads an additionalsealing insert (content of the adapter set) can be
mounted onto the existing sealing surface in the knurlednut.
3.1.4 Venting the System .
After installing the piston-cylinder system and the device under test, air maybe trapped in the system.
The system maybe vented before beginning the calibration using the following procedure:
The piston-cylinder systemand the device under test mustbe clamped, and the complete weight
set mustbe loaded on the piston-cylinder system.
Generate a pressure of approximately 50 bar using the priming pump
Increase the pressure with the spindle pump until just below the final value of the measuring range
of the piston-cylinder system,or o f the device under test (the smaller pressure range is the decisive
factor).
Important: The piston-cylinder system must remain in its lower position for this
operation, i.e. not y e t moving into equilibrium.
Open the outlet valve slowly, any trapped air will escape into the tank
This procedure may need to be repeated 1 to 2 times in order to remove all trapped air.
The device is now ready to use.
O-ring 8x2
(see accessories section 8.)
Knurled nut
Threaded insert

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3.2 Operation .
3.2.1 Procedure for single-range piston-cylinder system LR-Cal LDW-H-EKZ 1600 psi or120 bar .
3.2.1.1 Massloading .
Load the piston head wit h masses equivalent to the required pressure calibration point required.
Ensure the masses are correctly located in its respective spigot/recess.
Each masshas the following markings:
-Pressure Value
-Piston Area
-Weight Set number
For high accuracy calibration, an additional marking (letter or letter/number
combination) is marked on the mass.This is to identify masses of similar nominal
pressure values, and thus obtain the actual massvalue (grams) o f said item.
This piston-cylinder unit has a basic head massequivalent to 10 psi. If calibration is required in
another pressure unit, the first massapplied to the piston head should be the make-upmass(small
masswit h ‘+PISTON’ marking).
3.2.1.2 Approaching the pressure value .
The system mustfirst be filled with oil and pre-compressed.
For this the outlet valve mustbe closed.
Operate the priming pump for several strokes. The pressure increases to a maximum o f about 50
bar (depending on the volume o f the connected test specimen).
After that, increase the pressure by turning the built-in spindle pump clockwise.
Just before the generated pressure reaches the actual calibration point, the weights should be
rotated byhand (approx 30-40 RPM) tominimise the effect of friction.Care should be applied wh en
rotating the masses that no un-necessary transverse loads are applied to the piston.
Never rotate the piston-cylinder unit, if the piston is in the lower or upper block
position.
3.2.1.3 Pressure stable .
Continue generating pressure until the system is in astate of equilibrium.
As the pressure calibration point is achieved, the piston will begin to movein an upward direction to
its ‘FLOATING’ position. The‘FLOATING’ (free rotation) position is between 1-7mm above the
cylinder. To confirm this, the operator can press down lightly (use index finger) onto the top of the
masses applied. If the piston and masses appear to bounce (move freely up and down) the piston
unit is at pressure value of masses applied.
As there is only asmall pressure change required between the piston
floating/not floating werecommend turning the pump spindle slowly and evenly
clockwise.
The piston and thus the test pressure as we ll now remain stable for several minutes.

Deadweight Tester /PressureBalanceGB
LR-CalLDW-H
Operating InstructionsLR-CalLDW-H
20
3.2.2 Procedure for single-range piston-cylinder systemLR-Cal LDW-H-EKZ 4000 psi or 300 bar .
3.2.2.1 Massload .
The piston head has a tapped hole in its utmost surface. To achieve its initial start pressure value
(30 psi or 2 bar) a designated hexagonal massmustbe screwed into the piston head. This should
be applied before starting any calibration.
Load the piston head wit h masses equivalent to the required pressure calibration point required.
Ensure the masses are correctly located in its respective spigot/recess.
Each masshas the following markings:
-Pressure Value
-Piston Area
-Weight Set number
For high accuracy calibration, an additional marking (letter or letter/number
combination) is marked on the mass.This is to identify masses of similar nominal
pressure values, and thus obtain the actual massvalue (grams) o f said item.
3.2.2.2 Approaching the pressure value .
The system mustfirst be filled with oil and pre-compressed.
For this the outlet valve mustbe closed.
Operate the priming pump for several strokes. Thepressure increases to a maximum o f about 50
bar (depending on the volume o f the connected test specimen).
After that, increase the pressure by turning the built-in spindle pump clockwise.
Just before the generated pressure reaches the actual calibration point, the weights should be
rotated byhand (approx 30-40 RPM) tominimise the effect of friction.Care should be applied wh en
rotating the masses that no un-necessary transverse loads are applied to the piston.
Never rotate the piston-cylinder unit, if the piston is in the lower or upper block
position.
3.2.2.3 Pressure stable .
Continue generating pressure until the system is in astate of equilibrium.
As the pressure calibration point is achieved, the piston will begin to movein an upward direction to
its ‘FLOATING’ position. The‘FLOATING’ (free rotation) area is when the bottom edge of the
auxiliary cylinder fitted to the piston head has risen to a position within the knurledarea of the stud
fitted to the piston unit. To confirm this, the operator canpress down lightly (useindex finger) onto
the top of the masses applied. If the piston and masses appear to bounce (move freely up and
down) the piston unit is at pressure value of masses applied.
As there is only asmall pressure change required between the piston
floating/not floating werecommend turning the pump spindle slowly and evenly
clockwise.
The piston and thus the test pressure as we ll now remain stable for several minutes.