1、SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirelyvoluntary, and its applicability and suitability for any particular use, including any patent infringement arising therefro
2、m, is the sole responsibility of the user.”SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions.QUESTIONS REGARDING THIS DOCUMENT: (724) 772-8512 FAX: (724) 776-0243TO PLACE A DOCUMENT
3、 ORDER; (724) 776-4970 FAX: (724) 776-0790SAE WEB ADDRESS http:/www.sae.orgCopyright 1995 Society of Automotive Engineers, Inc.All rights reserved. Printed in U.S.A.SURFACEVEHICLE400 Commonwealth Drive, Warrendale, PA 15096-0001INFORMATIONREPORTSubmitted for recognition as an American National Stand
4、ardJ2254ISSUEDSEP95Issued 1995-09FLUID POWER PIPING CLEANING PROCESSForewordThis Document has not changed other than to put it into the new SAE Technical Standards BoardFormat.1. Scope1.1 The procedures and guidelines detailed in this SAE Information Report provide various techniques andprocesses to
5、 properly clean fluid power piping prior to assembly and operation.1.1.1 There are two recommended processes, pickling and flushing. Each procedure will remove particulatecontaminates if properly applied.1.2 Field of Application1.2.1 The process of conductor cleaning is applicable to hydraulic, lubr
6、ication, and pneumatic fluid powersystems.1.2.2 The conductor fabrication process of welding, brazing, heating, machining, and washing of tubing and pipes,causes contaminates to collect on the inside diameter of the conductor.1.2.3 If these contaminants are not properly removed and anticorrosive mea
7、sures taken, permanent conductordamage may result.1.2.4 Conductor cleaning and inspection must be done prior to system installation and assembly to remove anycontaminants.1.2.5 Proper conductor cleaning after assembly also assures that the system contamination level meets orexceeds acceptable operat
8、ing parameters prior to system start up.1.2.6 Hydraulic and lubrication systems require a cleanliness level which should meet cleanliness levelsestablished by ANSI/(NFPA/JIC)T2.24.1.1.2.7 This document should parallel O.E.M. and manufacturer procedures and standards to remove conductorassociated con
9、taminants prior to equipment assembly.SAE J2254 Issued SEP95-2-2. References2.1 Applicable PublicationsThe following publications form a part of the specification to the extent specifiedherein. Unless otherwise indicated the lastest revision of SAE publications shall apply.2.1.1 ANSI PUBLICATIONAvai
10、lable from ANSI, 11 West 42nd Street, New York, NY 10036-8002.ANSI/(NFPA/JIC) T.2.24.1Hydraulic Fluid PowerSystems standard for stationary industrial machinery2.1.2 ASTM PUBLICATIONAvailable from ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959.ASTM D 4174Standard Practice for Cleaning,
11、 Flushing, and Purification of Petroleum Fluid HydraulicSystems2.1.3 ISO PUBLICATIONAvailable from ANSI, 11 West 42nd Street, New York, NY 10036-8002.ISO 4406Hydraulic fluid powerFluidsMethod for coding level of contamination by solid particles2.2 Other PublicationsParker Hannifin Corporation - Tube
12、 Fittings DivisionThe Rexroth Corporation - Industrial Hydraulics DivisionVickers Incorporated3. Definitions3.1 Fluid power piping consists primarily of pipe, tubing, hoses, and fittings.3.2 Pickling will remove any contamination from pipes or tubing, especially corrosion, scale, slag and weld spatt
13、er.The pickling process is typically an acidic solution which chemically “attacks“ and loosens contaminateparticles.3.3 Flushing will remove dirt and other loose particle contaminates. The flushing solution does not chemically“attack“ contaminant particles. The flushing process may not remove all co
14、ntaminants. If contaminants arestill present, the pickling process should be performed.4. Pickling and Passivating4.1 General4.1.1 The pickling process should be used after any hot bending, brazing, silver soldering, or welding without anti-slag gas.4.1.2 Passivating the piping after pickling protec
15、ts the piping against rust for a limited time.4.1.3 Stainless steel pipe also requires pickling after welding.4.1.4 Black pipe may be purchased pre-pickled. The use of only pre-pickled pipe eliminates the possibility ofinventory stock mix-up and may eliminate the need for future pickling depending u
16、pon the application.4.1.5 The use of a professional pickling service is recommended.4.1.6 Pickling process techniques vary, but two basic methods exist, bath and circulation pickling. Each picklingprocess involves several steps which need to be performed correctly.SAE J2254 Issued SEP95-3-4.1.7 Prot
17、ective coatings or coarse contamination (i.e., steel chips, severe rust, etc.) should be removed prior toany machining or pickling process.4.1.8 Protective coatings can be removed through the use of degreasing agents. The degreasing process may beclassified as hot or cold. The processes vary due to
18、the degreasing agents involved.4.1.9 If degreasing is performed “in house“ all manufacturers safety precautions, practices, and procedures mustbe followed.4.1.10 Removal of coarse contaminants and protective coatings can be accomplished by sand-blasting.4.1.11 The sand-blasting process itself create
19、s additional contamination within the piping. This additionalcontamination can normally be removed with a properly applied pickling process.4.1.12 Care must be taken in long piping runs, especially those with bends and high spots where the picklingsolution may not completely remove the contaminants.
20、4.1.13 Two bath type pickling processes are available, multi-bath and single-bath.4.1.14 Multi-bath pickling involves several immersion steps, where as the single-bath process minimizes materialhandling.4.1.15 The advantage to multi-bath over single-bath is time. Multi-bath pickling may require 2 to
21、 3 h as compared toas many as 8 h to remove equivalent contamination levels in a single-bath application. Both methodssatisfactorily remove particulate contaminants from piping and tubing.4.2 Pickling Methods4.2.1 MULTI-BATH PICKLING4.2.1.1 Multi-bath pickling is the process normally used when there
22、 are large quantities of piping involved.4.2.1.2 Pickling facilities will degrease the pipe or tubing and immerse the piping in an acid bath. This acid bathtypically is a solution consisting of a 20 to 30% pure hydrochloric acid.4.2.1.3 Depending on the contamination (i.e., weld slag etc.) the pipin
23、g will typically remain in the solution forabout 2 h.4.2.1.4 The piping is then rinsed in a water bath to minimize transferal of the acidic solution into the neutralizationphase.4.2.1.5 To neutralize the acid, the piping is are placed in a bath of caustic soda and heated to about 70 C.4.2.2 SINGLE-B
24、ATH PICKLING4.2.2.1 Single-bath pickling incorporates all the previously mentioned multi-bath steps into one process. Thismethod of pickling is usually done for small scale applications.4.2.3 CIRCULATION PICKLING4.2.3.1 Circulation pickling is similar to a flushing process in that the pickling solut
25、ion is circulated through thepiping system. This process requires isolation of the piping and tubing from the other fluid powercomponents.SAE J2254 Issued SEP95-4-4.2.3.2 If fluid power components (including nonmetallic conductors, hoses, O-rings, etc.) are not isolated duringcirculation pickling, s
26、evere system damage to the fluid power system will occur.4.2.3.3 Circulation pickling is not recommended, the preferred method is to design the conductor system to allowindividual lengths of conductors to be disassembled and bath pickled.4.2.3.4 Bath pickling allows visual inspection of individual s
27、ections and provides a method of monitoring thepickling process for effectiveness.4.3 Post Pickle Cleaning4.3.1 Cleaning the “pickled“ piping, once completely dry, is accomplished by flushing the conductor with mineraloil. This prevents corrosion during storage and fabrication.4.3.2 The oil used mus
28、t be compatible with the fluid power operating system. The lubricating-flushing fluid must beas clean as the operating system cleanliness parameters.4.3.3 If contaminated or incompatible fluid is used to flush or lubricate the piping, the entire fluid power operatingsystem will be contaminated.4.3.4
29、 The piping once pickled and lubricated must be properly sealed and stored in a dry location. Proper storagewill eliminate the possibility of moisture condensation or airborne contaminates collecting on the insidediameter of the piping.4.3.5 An external protective coating, depending on future use, m
30、ay be implemented at this time.5. Flushing5.1 General5.1.1 The flushing of fluid power piping will remove dirt and contamination associated with the fabrication processof a system.5.1.2 Flushing of conductors prior to system start-up will eliminate unnecessary contamination from damaging thesystem.5
31、.1.3 Following basic guidelines and good housekeeping practices during fabrication will expedite contaminationremoval during the flushing process.5.1.4 Flushing involves circulating fluid through the piping at high velocities. The fast-flowing fluid carries thecontaminant particles through the fluid
32、.5.1.5 Filtering systems must be incorporated in the system to contain the contaminants.5.1.6 The duration and intensity of flushing depend on the original contamination level, volume of the pipingsystem, velocity of the flushing fluid, and the efficiency of the filters.5.1.7 The flushing process mu
33、st proceed until the flushing fluids contaminant level is less than normal systemoperating cleanliness parameters.5.1.8 Items, such as pumps, valves or any other devices that may be damaged during the flushing process mustbe bypassed or isolated.SAE J2254 Issued SEP95-5-5.1.9 Separate flushing syste
34、ms including pumps, heaters, and filters should be temporarily installed. Ventingvalves at high points and drains at low points may be installed to provide proper fluid flow paths duringflushing.5.1.10 Temporary alteration of the normal fluid power piping system may be required to provide adequate f
35、low ratesthrough all parts of the piping network.5.1.11 The flushing procedure will remove the necessary contaminates only if flow paths with adequate velocitiesare provided.5.1.12 The size of the system to be flushed and the capacity of the flushing equipment will determine if a fluid powersystem w
36、ill need to be isolated into several subsystems.5.1.13 The system design must incorporate access ports for this flushing process.5.1.14 Flushing velocity and fluid temperature should be higher than normal operating parameters.5.1.15 The recommended flow velocity should be at least twice that of the
37、normal operating system. The flow mustbe turbulent flow and may be described by Equation 1.(Eq. 1)where:Q = Volumetric flow, L/mind = Inside diameter of pipe, mmv = Viscosity, mm2/s5.1.16 The recommended operating temperature of the flushing system for mineral oils is 60 C.5.1.17 Water-in-oil emulsi
38、ons and water-glycol based fluid systems should be flushed at 50 C.5.1.18 The type of flushing fluid used must be compatible with the normal system operating fluid to be used in thesystem.5.1.19 If the flushing fluid is not compatible with the seals or any other component in the system, major system
39、damage will result.5.1.20 A lower viscosity, less expensive fluid may be used, consultation with the original equipment manufacturer orfluid supplier is recommended.5.1.21 The filters selected must be capable of filtering the fluid efficiently and have enough contaminant holdingcapacity to minimize
40、filter element replacement.5.2 Flushing Process5.2.1 Filtration of the flushing fluid prior to flushing is recommended. The fluid entering the system should be asclean as the flushing cleanliness target goal.5.2.2 The fluid should be heated to the required flushing temperature.5.2.3 Provide proper f
41、low paths for the system to be flushed (i.e., vents and drains).5.2.4 Isolate sections of the system if necessary.Q 0.11vdSAE J2254 Issued SEP95-6-5.2.5 Flush the system.5.2.6 Monitor the conditions of the filters and replace the elements as required.5.2.7 Reverse direction of flushing flow path.5.2
42、.8 Flushing should be continued until the flushing fluid meets or exceeds the targeted cleanliness level. Fluidsamples should be analyzed or a reliable particle counter be used to monitor fluid cleanliness.5.2.9 Discontinue the flushing process, drain the flushing fluid, and remove all residual flus
43、hing fluid payingparticular attention to low areas of the fluid power system.5.2.10 Reconfigure the piping system back to its normal operational state.5.2.11 During this portion extreme care must be taken to not contaminate the system during reassembly.5.2.12 The described flushing process is primar
44、ily used on new and rebuilt equipment installations and start-ups.5.2.13 This procedure can also be implemented on an existing system that has a contamination level detrimental tothe components in the system.6. Alternate Piping Cleaning Procedure6.1 An alternate cleaning/flushing procedure which is
45、an acceptable method of cleaning fluid power piping,primarily tubing.6.2 The following piping cleaning procedure applies toward individual component flushing prior to assembly on asystem.6.3 This procedure was originated because of the brazing process associated with some types of O-ring face sealtu
46、be fittings.6.4 This procedure is suggested after any brazing of tube fittings on fluid power systems. The processmechanically loosens the contaminants inside the tube and flushes the contaminants out with high pressurefluid.6.5 The recommended steps are as follows.6.5.1 Using stiff stainless steel
47、wire brush, loosen existing contaminants on the tube inside diameters, reaching asfar back towards the tube bend as possible.6.5.2 After loosening the contaminants on both ends, blow out the loose debris with compressed air.6.5.3 Clean I.D. of the tubes on both ends with high pressure water jet (app
48、roximately 3500 kPa (500 psi)similarto “do it yourself“ car washes.)6.5.4 Immediately after wash, flush the tubes with an ultra-clean solution (filtered to 21/18/14 cleanliness per ISO4406) of 115 g (4 oz) of Bemite 136 to 3.785 mL (1 gal) of water. This will clean the tubes, neutralize anyacidic re
49、sidue from the braze cleaner and provide temporary surface protection of up to 4 weeks.6.5.5 Flushing may be accomplished with either of the two ways described in 6.5.5.1 or 6.5.5.2 below:6.5.5.1 Pump the fluid through the tubes at a velocity of 6.1 m/s (20 ft/s) or more for about 30 s.SAE J2254 Issued SEP95-7-6.5.5.2 Fill the tubes about 75% full, cap both ends, and slosh the fluid from end to end vigorously several timesbefore draining it. Repeat the sloshing process (6.5.5.2) one more time.6.5.6 After the clean flush, coat I.D. of tubes with a clean rust inhibitor such
