ASTM D4241-98(2003)

Standard Practice for Design of Gas Turbine Generator Lubricating Oil Systems (Withdrawn 2008)

SIGNIFICANCE AND USE
This practice establishes minimum recommended design practices for gas turbine generator lubricating oil systems to ensure that:  
3.1.1 Lubrication, control, and seal functions will be performed satisfactorily by the oil mutually acceptable to the parties concerned.  
3.1.2 Installation, cleaning, and flushing will be facilitated.
3.1.3 Satisfactory system cleanliness can be maintained.
3.1.4 Safe practices are observed.
SCOPE
1.1 This practice covers the design of lubricating oil systems for gas turbine driven generator units 1000 kW and larger.
1.1.1 The lubricating oil system is defined as that assembly which utilizes and circulates the turbine generator lubricating oil and furnishes pressurized oil for control and seal functions.
1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
WITHDRAWN RATIONALE
This practice covers the design of lubricating oil systems for gas turbine driven generator units 1000 kW and larger.
This practice is being withdrawn due to lack of interest and support for its continued use.
Formerly under the jurisdiction of Committee D02 on Petroleum Products and Lubricants, this practice was withdrawn in October 2008.

General Information

• Status: Withdrawn
• Publication Date: 31-Oct-2003
• Withdrawal Date: 02-Dec-2008
• Technical Committee: D02 - Petroleum Products, Liquid Fuels, and Lubricants
• Drafting Committee: D02.C0.01 - Turbine Oil Monitoring, Problems and Systems

Relations

• Replaces: ASTM D4241-98 - Standard Practice for Design of Gas Turbine Generator Lubricating Oil Systems
• Effective Date: 01-Nov-2003
• Referred By: ASTM D6439-23 - Standard Guide for Cleaning, Flushing, and Purification of Steam, Gas, and Hydroelectric Turbine Lubrication Systems
• Effective Date: 01-Nov-2003

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
An American National Standard
Designation:D4241–98 (Reapproved 2003)
Standard Practice for
Design of Gas Turbine Generator Lubricating Oil Systems
This standard is issued under the fixed designation D 4241; 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 (e) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
Thispracticehasresultedfromaculminationoftheexperiencesoftheturbinebuilders,theerectors,
theoilsuppliers,andtheoperators.Outofnecessity,itisageneralizedandminimalstandard.Previous
issues of this practice have been used in specifications to aid in obtaining satisfactory performance of
the lubricating oil system.
1. Scope 3.1.3 Satisfactory system cleanliness can be maintained.
3.1.4 Safe practices are observed.
1.1 This practice covers the design of lubricating oil sys-
temsforgasturbinedrivengeneratorunits1000kWandlarger.
4. System
1.1.1 The lubricating oil system is defined as that assembly
4.1 The operation of the gas turbine generator depends upon
which utilizes and circulates the turbine generator lubricating
a satisfactory supply of lubricating oil at the proper places.
oil and furnishes pressurized oil for control and seal functions.
Thus, a highly reliable system must be supplied.
1.2 This standard does not purport to address all of the
4.2 The system flow requirements include the summation of
safety concerns, if any, associated with its use. It is the
the individual requirements for lubrication of all the bearings,
responsibility of the user of this standard to establish appro-
gear meshes, couplings supplied by the system, and the steady
priate safety and health practices and determine the applica-
stateandtransientcontroloilrequirements.Amarginshouldbe
bility of regulatory limitations prior to use.
added for flow changes with use.
2. Referenced Documents 4.3 The system pressure must be sufficient to overcome
piping and equipment pressure drop, overcome elevation head
2.1 ISO Standard:
difference, provide margin for regulation, and ensure proper
ISO 4572 Hydraulic fluid power-fillers-multi-pass method
distribution of lube oil to the required areas of the machinery.
for evaluating filtration performance
4.3.1 The control and seal oil function may require higher
3. Significance and Use pressure levels than the lubrication. For these cases, the total
system pressures may increase to where reasonable or separate
3.1 This practice establishes minimum recommended de-
control or seal oil pumps, or both, can be required.
sign practices for gas turbine generator lubricating oil systems
4.4 The designer should specify the maximum allowable oil
to ensure that:
viscosity for cold start. With reduced temperatures the in-
3.1.1 Lubrication, control, and seal functions will be per-
creased lube oil viscosity can have a significant affect upon the
formed satisfactorily by the oil mutually acceptable to the
reliable distribution of the oil throughout the system and upon
parties concerned.
the reliable operation of the controls.
3.1.2 Installation, cleaning, and flushing will be facilitated.
4.5 Heat is rejected from a number of sources to the
lubricating oil.
This practice is under the jurisdiction of ASTM Committee D02 on Petroleum
4.5.1 Bearing shearing and pumping losses are transferred
ProductsandLubricantsandisthedirectresponsibilityofSubcommitteeD02.C0on
to the lubricating oil.
Turbine Oils.
4.5.2 When accessory or load gearing are used, a major
All previous recommended practices have been published by ASME as joint
ASTM-ASME-NEMA standards. With the issuance of this document all standards
portion of their losses is transferred to the lubricating oil.
under the auspices of Technical Division C of ASTM Committee D02 will be
4.5.3 Lubricated couplings add heat to the oil.
published by ASTM, solely as ASTM standards. This standard replaces ASME
4.5.4 Because of the proximity of hot gas turbine parts,
Standard No. 120.
Current edition approved Nov. 1, 2003. Published November 2003. Originally some heat is transferred to the lube oil. This is especially true
approved in 1992. Last previous edition approved in 1998 as D 4241–98.
with buried bearings.
Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
4th Floor, New York, NY 10036.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D4241–98 (2003)
4.5.5 Pumping and throttling result in heat being added to 6.3.2 All connections and openings should be sealed to
the oil. minimize air leakage and the entrance of atmospheric contami-
4.6 Failure of the system to distribute lubricating oil to the nants into the reservoir.
required areas can result in significant damage to machinery. 6.3.3 Access openings and device mounting pads on hori-
Annunciating or machine tripping, or both, should be provided zontal surfaces should be raised from the normal surface to
for the following: reduce the entrance of contaminants into the reservoir.
4.6.1 Trip with low lube oil pressure. 6.3.4 Flanged submerged connections should be kept to a
4.6.2 Alarm for high oil temperature at the bearing header. minimum.
4.6.3 Alarm for high- or low-reservoir level, or both, 6.3.5 Oil reservoir connections for major drain lines from
depending upon the system design. bearings should be as far from the pump suction as practical or
baffled to prevent return oil from flowing directly to pump
5. Materials
suction, thereby providing a maximum oil rest period. Drains
5.1 Exposed devices and piping containing pressurized
should be arranged to provide for maximum deaeration and
lubricating oil should be of rugged construction and made of
minimum oil agitation.
high melting point materials.
6.3.6 The discharge of relief or regulating valves should be
5.1.1 Steel piping, tubing, valve bodies, fittings, and fabri- arranged to minimize air entrainment by discharge below oil
cations are acceptable and recommended. Valve and pump
level or over a deaeration tray.
bodies of cast iron can be used within the oil tank. 6.3.7 The reservoir and the oil system should be arranged
5.2 The use of copper, cadmium, zinc, and lead in systems
such that the entire system can be drained.
shouldbeavoidedduetothepoorresistancetocorrosionbyoil 6.4 The reservoir should be drainable.
oxidation products. In addition, these metals can serve as
6.4.1 The bottom of the reservoir should slope towards the
catalysts for accelerating oil oxidation processes. drain connections. For rectangular reservoirs, the slope should
5.2.1 Make sleeve bearing linings of high-tin base babbitt
be 20 mm/m ( ⁄4 in./ft) or greater. Small easily cleanable
with a minimum of 80 % tin.
reservoirs may not need the sloping bottom.
5.3 All materials used in system construction, including
6.4.2 Drain connections should be provided at the reservoir
gaskets,seals,diaphragms,interiorsurfacecoatings,andhoses,
low points. Precautions must be taken to prevent accidental
should be resistant to turbine lube oils and maintain adequate
draining of the oil. If drain valves are used, they should be
physical and chemical properties at maximum and minimum
locked closed or have blanks in the drain lines immediately
expected operating temperatures.
downstream.
5.4 Interior surfaces of steel reservoirs and major fabrica-
6.4.3 If connections for an external oil purification system
tions should be coated for rust protection with a material
are provided, they must be arranged and located so that
impervious to oil and water at the maximum expected tem-
siphoning of the reservoir below a safe level is not possible.
perature. If corrosion resistant materials are used, no coating is
6.5 Forced ventilation of the lube oil system vapor space
needed.
should be provided.
6.5.1 One method produces a vacuum for removal of gases
6. Oil Reservoirs
and vapors. This may use a vapor extractor or an air–operated
6.1 The lubricating oil is stored in the reservoir. The several
eductor. Internal baffles should have openings above the oil
components frequently mount from or within the reservoir. Oil
level to equalize the vacuum within the reservoir. The vacuum
distribution and return piping originate and terminate respec-
produced in the bearing housing should not average more than
tively from this assembly.
approximately 0.5 KPa (2 in. water) to minimize the entrance
6.2 Thecapacityofthereservoirisaffectedbythenecessary
of atmospheric contaminants into the oil system.
dwell time and the total system capacity.
6.5.2 Another method uses air pressurized seals in the
6.2.1 Toallowfortheseparationofentrainedair,thenormal
bearing housings. This air circulates through the vapor spaces
operatingoilvolumeshouldnotbelessthanfourtimestheflow
of the oil system and discharges through a vent.
per minute to the bearings. The exposed oil surface and oil
6.5.3 The reservoir extractor or vent connection should be
depth affect the air separation.
located to minimize oil vapor entrainment.
6.2.1.1 As an alternative, air separation may also be accom-
6.5.4 Care must be taken in location of the reservoir
plished through incorporation of mechanical separators,
ventilation discharge so that any oil vapors do not become
mounted internally to the reservoir, on each return connection.
entrained with the gas turbine inlet air.
Reservoir size shall then be determined by the separator space
6.5.5 The external vent outlet should be screened and
requirements and flow paths to limit short circuiting flow,
covered.
together with the provisions of 6.2.2.
6.5.6 For hydrogen cooled generator application, the reser-
6.2.2 The capacity of the reservoir should be sufficient to
voir should contain an explosion door or blowout diaphragm
hold the operating oil level volume, plus the volume that will
capable of maintaining the reservoir internal pressure at a safe
drain from the remainder of the system when the gas turbine
level at all times.
generator unit is shut down.
7. Pumps
6.3 Numerous factors contribute to the arrangement of the
reservoir, including the following: 7.1 Pumps must circulate lubricating oil from the reservoir
6.3.1 The entire inside of the reservoir should be accessible. to the bearings, controls, and other points of use. The pressure
D4241–98 (2003)
level must be high enough to ensure proper distribution and 7.5.7 The pump suction is defined as starting at the solid
satisfy control functions. fluid conveyance to the pump inlet. Normally this begins at
attachment of the suction strainer to the pump inlet or to the
7.1.1 Satisfactor
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