ASTM_D_4248_-_98_2003.pdf

Designation:D 4248 98(Reapproved 2003)An American National StandardStandard Practice forDesign of Steam Turbine Generator Oil Systems1This standard is issued under the fixed designation D 4248;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon(e)indicates an editorial change since the last revision or reapproval.INTRODUCTIONThe ever-increasing size and complexity of steam turbine generators makes the oil system moreimportant 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 toexpensive equipment with loss of system capability and increased generation costs due to the use ofless efficient equipment or the purchase of power through interconnections.This practice has resulted from a culmination of the experiences of the turbine builders,the erectors,the oil suppliers and the operators.Out of necessity,it is a generalized and minimal standard.Previousissues of this standard have been used in specifications to aid in obtaining satisfactory performance ofthe lubricating oil system.1.Scope1.1 This practice is applicable to steam turbine-generatorunits and provides recommended practices for the design of theoil system.1.1.1 The oil system is defined as that assembly which usesand circulates the turbine-generator lubricating oil.The oilsystem generally includes high pressure,bearing,control,generator seal,and drain systems.The system may also includethe supply and return lines for a boiler feed pump and hydrauliccoupling.1.2 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1ISO Standard:2ISO 4572 Hydraulic fluid power filters-multi-pass methodfor evaluating filtration performance3.Significance and Use3.1 The purpose of this guide for turbine generator oilsystems is to ensure that:3.1.1 Lubrication,control,and sealing will be performedsatisfactorily by the oil in a manner mutually acceptable to theparties 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.4.System Components4.1 Materials:4.1.1 Steel piping,tubing,valves,fittings,and fabricationplates are acceptable and recommended.The use of catalyticand corrodible materials,such as copper,zinc,and lead,shouldbe minimized,and if used,they should be properly alloyed.Bearing linings should be made of tin base babbitt.4.1.2 All materials used in system construction,includinggaskets,seals,diaphragms,interior permanent type surfacecoatings,and hoses,should be resistant to turbine oils andmaintain adequate physical and chemical properties at themaximum expected operating temperatures and service life.4.2 Pumps:4.2.1 Pumps must circulate lubricating oil from the reser-voir to the bearings,controls,and other points of use.Thepressure level must be high enough to ensure proper distribu-tion and satisfy control functions.4.2.1.1 Satisfactory circulation and pressure levels must beprovided for start-up,operation,and shut down.4.2.2 Several commonly used pumps are defined as follows:1This practice is under the jurisdiction of ASTM Committee D02 on PetroleumProducts and Lubricants and is the direct responsibility of Subcommittee D02.C0 onTurbine Oils.All previous recommended practices have been published by ASME as jointASTM-ASME-NEMA standards.With the issuance of this document,all standardsunder the auspices of Subcommittee C of ASTM Committee D02 will be publishedby ASTM as ASTM standards.This standard replaces ASME Standard Practice No.116.Current edition approved Nov.1,2003.Published November 2003.Originallyapproved in 1983.Last previous edition approved in 1998 as D 4248-98.2Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036.1Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.4.2.2.1 The main pump normally supplies the oil circulationand pressure for the steam turbine generator operation.4.2.2.2 The auxiliary pump is sized to permit continuedoperation if the main pump fails.4.2.2.3 The emergency pump is of reduced capacity.Itsfunction is to provide last resort lubrication for coastdown,should the other pumping fail.4.2.2.4 Many combinations of pumps can be satisfactory.Asa minimum these should be two pumps driven from twoindependent and different power sources.Thus,no singleincident or equipment failure can cause loss of pumping.(1)An exception can be made to the two pump recommen-dation if the turbine generat