ASTM D4248-98(2003)

Standard Practice for Design of Steam Turbine Generator Oil Systems (Withdrawn 2008)

SIGNIFICANCE AND USE
The purpose of this guide for turbine generator oil systems is to ensure that:
3.1.1 Lubrication, control, and sealing will be performed satisfactorily by the oil in a manner 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 is applicable to steam turbine-generator units and provides recommended practices for the design of the oil system.
1.1.1 The oil system is defined as that assembly which uses and circulates the turbine-generator lubricating oil. The oil system generally includes high pressure, bearing, control, generator seal, and drain systems. The system may also include the supply and return lines for a boiler feed pump and hydraulic coupling.
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WITHDRAWN RATIONALE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 is applicable to steam turbine-generator units and provides recommended practices for the design of the oil system.
This practice is being withdrawn due to lack of interest and support for its continued use.
Formerly under the jurisdiction of Committee D02 on Petroleum Products and Lubricants, this practice was withdrawn in October 2008.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• Status: Withdrawn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 D4248-98 - Standard Practice for Design of Steam Turbine Generator 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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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:D4248–98 (Reapproved 2003)
Standard Practice for
Design of Steam Turbine Generator Oil Systems
This standard is issued under the fixed designation D 4248; 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
The ever-increasing size and complexity of steam turbine generators makes the oil system more
important than ever. The system is required to provide not only lubrication but surface protection,
cooling, sealing, and control as well. Failure in any one of these functions could result in damage to
expensive equipment with loss of system capability and increased generation costs due to the use of
less efficient equipment or the purchase of power through interconnections.
Thispracticehasresultedfromaculminationoftheexperiencesoftheturbinebuilders,theerectors,
the oil suppliers and the operators. Out of necessity, it is a generalized and minimal standard. Previous
issues of this standard have been used in specifications to aid in obtaining satisfactory performance of
the lubricating oil system.
1. Scope 3. Significance and Use
1.1 This practice is applicable to steam turbine-generator 3.1 The purpose of this guide for turbine generator oil
unitsandprovidesrecommendedpracticesforthedesignofthe systems is to ensure that:
oil system. 3.1.1 Lubrication, control, and sealing will be performed
1.1.1 The oil system is defined as that assembly which uses satisfactorily by the oil in a manner mutually acceptable to the
and circulates the turbine-generator lubricating oil. The oil parties concerned.
system generally includes high pressure, bearing, control, 3.1.2 Installation, cleaning, and flushing will be facilitated.
generator seal, and drain systems.The system may also include 3.1.3 Satisfactory system cleanliness can be maintained.
thesupplyandreturnlinesforaboilerfeedpumpandhydraulic 3.1.4 Safe practices are observed.
coupling.
4. System Components
1.2 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the 4.1 Materials:
4.1.1 Steel piping, tubing, valves, fittings, and fabrication
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica- plates are acceptable and recommended. The use of catalytic
and corrodible materials, such as copper, zinc, and lead, should
bility of regulatory limitations prior to use.
be minimized, and if used, they should be properly alloyed.
2. Referenced Documents
Bearing linings should be made of tin base babbitt.
2.1 ISO Standard: 4.1.2 All materials used in system construction, including
ISO 4572 Hydraulic fluid power filters-multi-pass method gaskets, seals, diaphragms, interior permanent type surface
for evaluating filtration performance coatings, and hoses, should be resistant to turbine oils and
maintain adequate physical and chemical properties at the
maximum expected operating temperatures and service life.
This practice is under the jurisdiction of ASTM Committee D02 on Petroleum
4.2 Pumps:
ProductsandLubricantsandisthedirectresponsibilityofSubcommitteeD02.C0on
4.2.1 Pumps must circulate lubricating oil from the reser-
Turbine Oils.
All previous recommended practices have been published by ASME as joint
voir to the bearings, controls, and other points of use. The
ASTM-ASME-NEMA standards. With the issuance of this document, all standards
pressure level must be high enough to ensure proper distribu-
under the auspices of Subcommittee C ofASTM Committee D02 will be published
tion and satisfy control functions.
byASTM asASTM standards. This standard replacesASME Standard Practice No.
116. 4.2.1.1 Satisfactory circulation and pressure levels must be
Current edition approved Nov. 1, 2003. Published November 2003. Originally
provided for start-up, operation, and shut down.
approved in 1983. Last previous edition approved in 1998 as D 4248-98.
4.2.2 Several commonly used pumps are defined as follows:
Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
4th Floor, New York, NY 10036.
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D4248–98 (2003)
4.2.2.1 The main pump normally supplies the oil circulation 4.3.1 The capacity of the reservoir should be sufficient to
and pressure for the steam turbine generator operation. hold the sum of the operating oil volume contained within the
normaloperatingrangeplusthevolumethatwilldrainfromthe
4.2.2.2 The auxiliary pump is sized to permit continued
remainder of the system when the turbine generator unit is
operation if the main pump fails.
shutdown.
4.2.2.3 The emergency pump is of reduced capacity. Its
4.3.2 To allow for the separation of entrained air and the
function is to provide last resort lubrication for coastdown,
settling by gravity of water and solid contaminants the normal
should the other pumping fail.
operating oil volume should not be less than five times the flow
4.2.2.4 Manycombinationsofpumpscanbesatisfactory.As
per minute to the bearings.
a minimum these should be two pumps driven from two
4.3.3 A drain connection should be provided at the lowest
independent and different power sources. Thus, no single
point on the reservoir.Ashut off valve should be located in the
incident or equipment failure can cause loss of pumping.
drain near the reservoir.To avoid accidental draining of the oil,
(1) An exception can be made to the two pump recommen-
the valve should be locked closed or have a blank in the drain
dation if the turbine generator can survive shut-downs without
line immediately downstream.
oil circulation.
4.3.4 The bottom of the reservoir should slope towards the
4.2.3 Examples of these pump drive combinations are listed
drain connection. On rectangular reservoirs the slope should be
as follows:
40 mm/m ( ⁄2 in./ft) or greater.
Main Auxiliary Emergency
4.3.5 Connections for the oil purification system should be
shaft ac motor dc motor
provided.Thesupplyshouldbesolocatedthatoilistakenfrom
shaft none ac/dc motor
as close as possible to the reservoir bottom. Both the supply
shaft ac motor turbine
ac motor none dc motor and return connections should be arranged and located so that
siphoning of the reservoir below a safe level is not possible.
4.2.4 The auxiliary and emergency pump drivers shall be
4.3.6 Oil reservoir connections for major drain lines from
sized for adequate capacity when operating with the oil
bearings should be as far from the pump suction as practical or
viscosity corresponding to the minimum temperature for start-
baffled to prevent return oil from flowing directly to pump
up.
suction, thereby providing a maximum oil rest period. Drains
4.2.5 Control of the auxiliary and emergency pump drivers
should be arranged to provide for maximum deaeration and
can significantly affect reliability.
minimum oil agitation.
4.2.5.1 The auxiliary and emergency pump drive controls
4.3.7 A method for oil level determination should be pro-
shall provide for automatic starting and in-service testing.
vided.
4.2.5.2 The pump motor overloads shall not trip the motor
4.3.8 The discharge of relief valves should be at least 150
breaker. The overload shall only provide a warning.
mm (6 in.) below the operating oil level.
4.2.6 Several application requirements shall be considered
4.3.9 Avapor extractor connected to the highest point of the
for proper pump functioning.
reservoir should be provided for the removal of gases and
4.2.6.1 The main shaft driven pump shall have adequate
vapors. Internal baffles should have openings above the oil
suction conditions to provide uninterrupted supply of oil.
level to equalize the vacuum within the reservoir. The vacuum
Pumps shall be provided with a positive suction.
producedinthebearinghousingsshouldnotaveragemorethan
4.2.6.2 Pump suctions shall be below the minimum reser-
approximately 0.5 KPa (2 in. water) to minimize the entrance
voir operating level. The exact submergence will be deter-
of atmospheric contaminants into the oil system.
mined by the pump suction requirements including the consid-
4.3.10 The interior surfaces wherever possible should be
eration of air entrainment in the pump suction. In many cases
protected by a permanent type, oil resistant surface coating
thepumpsuctionisatleast150 mm(6in.)belowthe
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