ASTM D4174-89(2010)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:D4174 −89(Reapproved 2010)
Standard Practice for
Cleaning, Flushing, and Purification of Petroleum Fluid
Hydraulic Systems
This standard is issued under the fixed designation D4174; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
Section
Supplementary Methods 6.3.3
1.1 Thispracticecoversaidfortheequipmentmanufacturer,
Limitations of Contamination Control Devices 6.3.4
the installer, the oil supplier and the operator in coordinating Storage 7
General 7.1
their efforts towards obtaining and maintaining clean petro-
Inspection 8
leum fluid hydraulic systems. Of necessity, this practice is
General 8.1
generalized due to variations in the type of equipment, build- System Components 8.2
Valves, Strainers and Coolers 8.2.1
er’s practices, and operating conditions. Constant vigilance is
Sumps and Tanks 8.2.2
required throughout all phases of design, fabrication,
Control Devices 8.2.3
Pumps 8.2.4
installation, flushing, testing, and operation of hydraulic sys-
Flushing Program 9
tems to minimize and reduce the presence of contaminants and
General 9.1
to obtain optimum system reliability.
Preparation of System for Flushing 9.2
Oil Heating Prior to Flushing 9.3
1.2 This practice is presented in the following sequence:
Selection of Flushing Oil 9.4
System Operation Oil 9.4.1
Section
Special Flushing Oil 9.4.2
Scope 1
Flushing Oil Selection Guide 9.4.3
Referenced Documents 2
Flushing Procedure for New Systems 9.5
Significance and Use 3
Flushing Oil Charge 9.5.1
Definitions 4
Cleaning of Filtration Devices 9.5.2
Types of Contamination 5
Cleaning of System Components 9.5.3
General 5.1
System Flushing 9.5.4
Water 5.2
Draining of Flushing Oil 9.5.5
Soluble Contaminants 5.3
Displacement Oil 9.5.6
Insoluble Contaminants 5.4
Interim Corrosion Protection 9.5.7
Lodged Contamination 5.4.2.1
New Fluid Charge 9.5.8
Suspended Contamination 5.4.2.2
Flushing of Used Systems 9.6
Contamination Control 6
General Guidelines 9.6.1
General 6.1
Procedure 9.6.2
Initial Filling 6.1.1
System Maintenance 10
In-Service Units 6.1.2
Shipping 10.1
Connection of Contamination Control System 6.1.3
Preinstallation 10.2
Piping to Contamination Control System 6.1.4
In-Service Units 10.3
Contamination Control Procedures 6.2
Decision to Flush In-Service Hydraulic Systems 10.4
Full Flow Contamination Control 6.2.1
Fluid Condition Monitoring 11
Bypass Contamination Control 6.2.2
Fluid Sampling Techniques 11.2
Batch Contamination Control 6.2.3
Visual Inspection 11.3
Contamination Control Processes 6.3
Laboratory Analysis 11.4
Gravity 6.3.1
Fluid Cleanliness Criteria 11.5
Mechanical 6.3.2
General Information 12
Centrifuge 6.3.2.1
Filter Ratings 12.2
Filters 6.3.2.2
Centrifuge Ratings 12.3
Coalescence 12.4
Vacuum Dehydration 12.5
This practice is under the jurisdiction ofASTM Committee D02 on Petroleum
Adsorption 12.6
Products and Lubricants and is the direct responsibility of D02.N0.02 on Industrial
Applications.
1.3 The values stated in SI units are to be regarded as the
Current edition approved Oct. 1, 2010. Published November 2010. Originally
standard. The values given in parentheses are for information
approved in 1982. Last previous edition approved in 2005 as D4174–89(2005).
only.
DOI: 10.1520/D4174-89R10.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D4174−89 (2010)
1.4 This standard does not purport to address all of the uisites are meaningless unless the hydraulic system is initially
safety concerns, if any, associated with its use. It is the cleaned to a level that will prevent component damage on
responsibility of the user of this standard to establish appro- initial start up or when debris may be dislodged by any system
priate safety and health practices and determine the applica- upset.
bility of regulatory limitations prior to use.
4.2 The cleaning and flushing of both new and used systems
are accomplished by essentially the same procedure. In new
2. Referenced Documents
systems, the emphasis is on the removal of contaminants
2.1 ASTM Standards:
introduced during the manufacture, storage, field fabrication,
D445 Test Method for Kinematic Viscosity of Transparent
and installation. In used systems, the emphasis is on the
and Opaque Liquids (and Calculation of Dynamic Viscos-
removal of contaminants that are generated during operations,
ity)
from failures that occur during operation; or contaminants
D664 Test Method for Acid Number of Petroleum Products
introduced during overhaul.
by Potentiometric Titration
4.3 While the flushing and cleaning philosophies stated in
D974 Test Method for Acid and Base Number by Color-
this practice are applicable to all primary and servo hydraulic
Indicator Titration
systems, the equipment specified herein does not apply to
D1774 Test Method for Elastic Properties of Textile Fibers
3 compact systems that use relatively small volumes of fluid
(Withdrawn 2000)
unless they are servo systems where it is economically justi-
D2709 Test Method for Water and Sediment in Middle
fied.
Distillate Fuels by Centrifuge
4.4 It should be emphasized that the established procedures
D4006 Test Method for Water in Crude Oil by Distillation
F311 Practice for Processing Aerospace Liquid Samples for to be followed for flushing and cleaning the hydraulic systems
should be accomplished through the cooperative efforts and
Particulate ContaminationAnalysis Using Membrane Fil-
ters agreement of the equipment manufacturer, the installer, the
operator, and the fluid supplier. No phase of these procedures
F312 Test Methods for Microscopical Sizing and Counting
Particles from Aerospace Fluids on Membrane Filters should be undertaken without a thorough understanding of the
possible effects of improper system preparation. The installa-
F313 Test Method for Insoluble Contamination of Hydraulic
tion and cleaning and flushing of the equipment should not be
Fluids by Gravimetric Analysis (Withdrawn 1988)
entrusted to persons lacking in experience.
2.2 ANSI Standards:
B93.2 Glossary of Terms for Fluid Power
5. Types of Contamination
B93.19 Method for Extracting Fluid Samples from the Lines
of an Operating Hydraulic Fluid Power System (for
5.1 General—Hydraulic systems can become contaminated
Particulate Contamination Analysis)
fromavarietyofsources.Generally,therearefivecategoriesof
contamination: (1) water, (2) fluid soluble material, (3) fluid
3. Terminology
insoluble material, (4) erroneous fluid additions, and (5)
3.1 Definitions:
hydraulic fluid deterioration. Properly designed systems can
3.1.1 absolute filtration rating—the diameter of the largest
normally control water and insoluble contaminants; however,
hard spherical particle that will pass through a filter under
when it is necessary to remove soluble contaminants, a fluid
specified test conditions. This is an indication of the largest
change and flush are required.
opening in the filter element.
5.2 Water—Water is almost always present in hydraulic
3.1.2 nominal filtration rating—an arbitrary micrometre
fluids. It may be present in solution or in a free or emulsified
value indicated by a filter manufacturer. Due to lack of
form. Water can exist in solution at varying concentrations
reproducibility this rating is deprecated. (ANSI B93.2)
depending on the nature of the fluid, the temperature, and so
forth. For example, hydraulic fluid may hold 50 ppm of water
4. Significance and Use
at 21°C (70°F) and 250 ppm at 71°C (160°F). The water in
4.1 Proper fluid condition is essential for the satisfactory
solution has no adverse effect on lubricating properties of the
performance and long life of the equipment. Prerequisites for
fluid and causes no corrosion; however, when fluid passes
proper lubrication and component performance are: ( 1)a
through a cooler some water may come out of solution and
well-designedhydraulicsystem,(2)theuseofagoodfluid,and
become free water in the form of finely dispersed droplets.
(3) a maintenance program including proper filtration methods
Many contaminants hinder the separation of this free water
to ensure that the fluid is free of contaminants. These prereq-
from the fluid by settling and may cause an emulsion. In
hydraulic fluids, the emulsion impairs circulation, interfere
with lubrication and adversely affect contamination control
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
equipment.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
5.2.1 Water contamination can be classified as either fresh
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
or sea water, as encountered in land or marine systems. Fresh
The last approved version of this historical standard is referenced on
water enters the hydraulic system from moist air as condensa-
www.astm.org.
tion, through improperly located vents, leaks in coolers, and
Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
4th Floor, New York, NY 10036. steamheaters,andbecauseofimproperoperation.Seawater,in
D4174−89 (2010)
marine hydraulic systems, enters through leaks in coolers, 5.4.2 Harmful contamination can exist in the hydraulic
faulty manhole gaskets, faulty sump tank seals and improperly system in two forms:
located vents. Sea and brackish water can also present a
5.4.2.1 Lodged Contamination—These contaminants may
problem when used as a coolant in land-based units. Water become dislodged by high fluid flows and temperature differ-
contamination in hydraulic fluids can:
entials or by induced vibration during flushing. Contamination
5.2.1.1 Promote fluid oxidation. can be lodged in unflushed pockets or settled on the bottom of
5.2.1.2 Reduce fluid stability.
tanks. Unless this contaminant is removed, it becomes dis-
5.2.1.3 Promote sludge. lodged during startup or during system upsets. Experience,
5.2.1.4 Promote foaming.
good judgement, and careful inspection by the installation
5.2.1.5 Form emulsions. supervisormustbereliedupontodeterminewhensuchdirthas
5.2.1.6 Promote rusting and corrosion.
been satisfactorily removed.
5.2.1.7 Affect additive and concentration.
5.4.2.2 Suspended Contamination:
5.2.1.8 Adversely affect lubricating properties.
5.4.2.3 (a) Contaminants suspended in the fluid can be
5.2.1.9 Promote bacteria growth.
generated by particles coming loose from pipe, hose, hydraulic
5.2.1.10 Alter fluid viscosity.
components,tankwallsgenerallycausedbyhighfluidvelocity,
5.2.1.11 Adversely affect fine filtration.
wear debris, and vibration. Suspended contaminant can be
5.2.2 In the case of severe salt water contamination, it is
measured, as described in 11.3. To prevent the level of
necessary to remove the operating fluid and clean and flush the
suspended contaminant from getting beyond acceptable limits,
hydraulic systems.
all units should be provided at least with a bypass contamina-
tion control system (fluid filter or centrifuge). Preferably a full
5.3 Soluble Contaminants:
flow filter or a full flow filter plus bypass purification is
5.3.1 Soluble contaminants in hydraulic systems include
provided. When a full flow filter is used, a bypass purification
cleaning chemicals, solvents, rust preventives, incompatible
system may not be required.
lubricants, flushing oils, extraneous oils, oxidation products,
5.4.2.4 (b) The bypass or full flow system, or both, are in
gasket sealants, and assembly lubricants. These contaminants
operation during the flush operation as well as on a continuous
cannotberemovedbyconventionalfluidcontaminationcontrol
basis during hydraulic system operation. The rated flow capac-
equipment. Normally, a new charge of fluid is required to
ity per hour of a bypass system should be 10 to 20 % of the
correct the problem. Fluid soluble contaminants can:
total system fluid volume.
5.3.1.1 Change the fluid viscosity.
5.3.1.2 Alter the flash point.
6. Contamination Control
5.3.1.3 Change the color.
5.3.1.4 Result in sludge deposits.
6.1 General—Contamination control in a hydraulic system
5.3.1.5 Attack elastomeric seals.
is the complete program of monitoring and maintaining a clean
5.3.1.6 Initiate additive-water interaction that can cause
fluid. Contamination control must begin with the design,
emulsification, possible additive loss, instability, impaired
manufacture, and installation of the hydraulic system and
purification equipment performance, foaming, and air entrain-
continue throughout the life of the system. When making
ment.
inspections or working in or around a unit, care must be taken
5.3.1.7 Accelerate oxidation.
to prevent contaminants from entering the system. When work
5.3.2 When a soluble contaminant is present, the fluid
that generates contaminants is being performed in the vicinity
supplier and consult the equipment manufacturer should be
of the hydraulic system, the system components must be
consulted regarding the advisability of continued use of the
protected even to the extent of suspending operations, and
fluid or replacing it with a new charge.
requiring system components to be sealed until the contami-
nating activity has ceased. The contamination control system
5.4 Insoluble Contaminants:
must be capable of removing water and particulate matter
5.4.1 Insoluble contaminants normally encountered are
consistentwithcontaminationtoleranceandsystemcleanliness
metal particles of all types and sizes, fibers, airborne solids,
requirements.
sand, and other nonmetallic particles. These contaminants are
6.1.1 Initial Filling—When initially filling the hydraulic
often the result of improper manufacturing techniques, im-
proper shipping and storage practices, and careless installation system, all fluids are filtered through 3 to 10-µm absolute (see
4.1) filters as they are being transferred into the reservoir. The
of hydraulic systems. Some of the effects of solid contamina-
contaminationcontrolsystemisreadyforoperationpriortothe
tion are:
hydraulic system fill and is operating throughout flushing. See
5.4.1.1 Abrasive wear or sticking of components such as:
Section 9.5.
control valve poppets, cylinders, piston rods, and seals.
5.4.1.2 Faulty control functioning, particularly plugged 6.1.2 In-Service Units—The contamination control system
fluid lines/filter plugging. is in operation as long as the hydraulic system is in service. Its
5.4.1.3 Reduced fluid stability. operationisfrequentlyandregularlymonitoredtoassurethatit
5.4.1.4 Sludge formation. is performing adequately and to determine the need for its
maintenance.
5.4.1.5 I
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