1、Designation: D 3923 08Standard Practices forDetecting Leaks in Reverse Osmosis and NanofiltrationDevices1This standard is issued under the fixed designation D 3923; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last r
2、evision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 These practices cover detecting leaks in which there is adirect communication between the feed or concentrate, or both,and t
3、he permeate. Several types of leaks are possible with thevarious configurations of reverse-osmosis (RO) and nanofiltra-tion (NF) devices.1.2 Types of Leaks:1.2.1 With hollow-fiber devices, feed or concentrate leak-age, or both, into the permeate stream by leaks through the tubesheet and past the tub
4、e sheet O-ring are possible. “Leaks”caused by broken fibers are not covered by these practices.1.2.2 With spiral-wound devices, leaks may occur throughdamage of the membrane surface itself by punctures orscratches, by glue-line failure, and by O-ring leaks on producttube interconnectors.1.2.3 With t
5、ubular devices, leaks due to membrane damage,tube end seal leaks, and leaks from broken tubes or productheaders are possible.1.3 Three leak test practices are given as follows:SectionsPractice ATube Sheet and O-Ring Leak Test for HollowFiber Devices8 to 9Practice BVacuum Test for Spiral Wound Device
6、s 10 to 12Practice CDye Test for Spiral Wound and Tubular Devices 13 to 181.4 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
7、 the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 1129 Terminology Relating to WaterD 1193 Specification for Reagent WaterD 4194 Test Methods for Operating Characteristics of Re-verse Osmosis and Nanofiltration DevicesD 6161 Terminology Used for
8、Microfiltration, Ultrafiltra-tion, Nanofiltration and Reverse Osmosis Membrane Pro-cessesD 6908 Practice for Integrity Testing of Water FiltrationMembrane SystemsE60 Practice for Analysis of Metals, Ores, and RelatedMaterials by Molecular Absorption SpectrometryE 275 Practice for Describing and Meas
9、uring Performanceof Ultraviolet, Visible, and Near-Infrared Spectrophotom-eters3. Terminology3.1 For definitions of terms used in these practices, refer toTerminology D 1129 and D 6161.3.2 Definitions of Terms Specific to This Standard:3.2.1 leakbypassing of the intact membrane from thefeed side to
10、the permeate side.4. Summary of Practice4.1 The hollow-fiber device being tested is operated at lowpressure with the permeate tube sheet exposed (the fiber bundleis held in place by a “spider” device designed for the specificmodel under test). Any significant leak in the tube sheet orO-ring seal is
11、detected visually by inspection.5. Significance and Use5.1 These practices may be used to determine whether a ROor NF device is free of leaks if the mechanical integrity of thedevice is to be confirmed. They may also be used to detectleaks in RO or NF devices whose operating performanceindicates a p
12、ossible leak. These practices may be used foreither new or used devices.6. Apparatus6.1 “Spider” Device, designed for the specific model ofhollow-fiber device being tested, is available from the supplier.The “spider” is designed to take the place of the permeate endplate and permeate collection grid
13、/block while securing the1These practices are under the jurisdiction of ASTM Committee D19 on Waterand are the direct responsibility of Subcommittee D19.08 on Membranes and IonExchange Materials.Current edition approved Oct. 1, 2008. Published November 2008. Originallyapproved in 1980. Last previous
14、 edition approved in 2003 as D 3923 94 (2003)1.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright AST
15、M International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.fiber bundle from movement. This allows visual observationduring low-pressure operation with the fiber bundle retained inits original position.7. Purity of Reagents7.1 Reagent grade chemicals shall b
16、e used in all tests.Unless otherwise indicated, it is intended that all reagents shallconform to the specifications of the Committee on AnalyticalReagents of the American Chemical Society, where suchspecifications are available.3Other grades may be used,provided it is first ascertained that the reag
17、ent is of sufficientlyhigh purity to permit its use without lessening the accuracy ofthe determinations.7.2 Unless otherwise indicated, references to water shall beunderstood to mean Type III reagent water conforming toSpecification D 1193.PRACTICE ATUBE SHEET AND O-RING LEAKTEST FOR HOLLOW FIBER DE
18、VICES8. Scope8.1 This practice is applicable to detecting feed or concen-trate leakage, or both, through the tube sheet and past the tubesheet O-ring into the permeate in hollow-fiber devices.9. Procedure9.1 Drain the liquid from the feed side of the membrane.9.2 Connect a centrifugal pump with 1.4
19、MPa (200 psig)capability and a throttling valve to the feed port of thehollow-fiber device. Install a pressure gage and valve on theconcentrate port of the RO or NF device.9.3 Remove the permeate end plate and auxiliary equipmentin accordance with the suppliers instructions to expose theface of the
20、permeate tube sheet.9.4 Install a “spider” device (available from supplier) de-signed for the specific model under test and secure the “spider”with the snap or segmented ring that held the permeate endplate in place.9.5 Place the hollow-fiber device in the horizontal positionand orient the open conc
21、entrate line to the highest point (12oclock). Allow water to flow through the device at linepressure (approximately 350 kPa; 50 psig) to remove anytrapped air in the device. Slowly close concentrate line valve topressurize the unit to 350 kPa (50 psig). While standing clearof the tube sheet, start t
22、he pump and increase pressure slowlyuntil a maximum pressure of 1.05 MPa (150 psig) is obtained.Proceed with the tube sheet inspection.NOTE 1The leak test should take approximately 15 min to determinethe integrity of the tube sheet and tube sheet O-ring.9.6 Examine for leaks by observing the product
23、 water as itexits the tube sheet face. If leaks do not exist, the product waterappears to ooze out from the tube sheet face. However, if asignificant leak is present in the tube sheet or O-ring seal, aforceful spray or stream will be observed. During inspection,rotate the device 180 to examine the l
24、ower portion of the tubesheet for leaks. This is necessary since leaks in the lowerportion of the tube sheet are not easily discernible because ofthe accumulation of product water.9.7 Shutdown Procedure:9.7.1 Shut off the centrifugal pump and allow the pressure toreach zero before disconnecting the
25、RO or NF device.9.7.2 Replace permeate end plate and all auxiliary equip-ment in accordance with the suppliers instructions.9.7.3 Take care to ensure that the membranes are kept wet atall times and are properly sanitized or winterized, or both,(based on suppliers recommendations) for long-term stora
26、ge(more than 5 days).PRACTICE BVACUUM TEST FOR SPIRAL WOUNDDEVICES10. Scope10.1 This practice is applicable to detecting leaks in spiral-wound RO or NF devices, new or used, when such leaks aresignificant enough to prevent the device from holding avacuum. These leaks may be due to a damaged membrane
27、,glue-line failure, or leaks in O-ring seals. This test is useful asa screening procedure and is not intended as a means ofabsolute verification of such leaks (see Practice D 6908).11. Summary of Practice11.1 The device is evaluated with one end of the permeatecollection tube sealed. A vacuum gage o
28、n the other end of thetube is observed. A rapid decay in vacuum indicates a leak.12. Procedure12.1 Drain the liquid from the feed side of the membraneand let it remain open to the atmosphere. For membranedevices placed horizontally, the feed and exit ports must belocated on the bottom of the device
29、housings in order for thistest to work.12.2 Seal one end of the permeate collection tube with asuitable leak-tight cap. Connect the other end of the permeatetube to a vacuum gage and a valved vacuum source.12.3 Evacuate the element to 84 to 101 kPa vacuum (25 to30 in. Hg vacuum). Close the isolation
30、 valve and observe thereading on the vacuum gage. Note the rate at which the vacuumdecays.Arapid decay (greater than 20 kPa/ min (6 in. Hg/min)will indicate the presence of a leak.12.4 Shutdown Procedure:12.4.1 Slowly release the vacuum on the RO or NF deviceand allow the device to reach atmospheric
31、 pressure beforedisconnecting.12.4.2 Take care to ensure that the membranes are kept wetat all times and are properly sanitized or winterized, or both,for long-term storage (based on suppliers recommendations).3Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Wa
32、shington, DC. For Suggestions on the testing of reagents notlisted by the American Chemical Society, see Annual Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.D392308
33、2PRACTICE CDYE TEST FOR SPIRAL WOUNDANDTUBULAR DEVICES13. Scope13.1 This practice is applicable to detecting leaks in spiralwound or tubular RO or NF devices, new or used, which aredue to lack of or loss of mechanical integrity. (see PracticeD 6908)14. Summary of Practice14.1 The practice consists o
34、f passing a solution of a dye,known to be rejected by the membrane, through the deviceunder standard conditions as specified in Test Methods D 4194.The concentration of the dye in the permeate relative to that inthe feed is measured either spectrophotometrically or by visualcomparison of the color i
35、ntensity.Adye passage of greater than0.5 % indicates a leak. The dye chosen should be known to notabsorb to the membrane under study.15. Apparatus15.1 The test apparatus required is schematically describedin Test Methods D 4194.15.2 Nessler Tubes or PhotometerA set of 50-mLmatched Nessler tubes or a
36、 photometer suitable for measure-ments at a wavelength of 590 nm is required.NOTE 2Filter photometers and photometric practices used in thispractice shall conform to Practice E60. Spectrophotometers shall conformto Practice E 275.16. Reagents16.1 Dye Feed Solution (Methyl Violet 2B)Prepare a100-mg/L
37、 dye feed solution by adding 0.1 g of methyl violet2B/L of solution to water containing 1.5 g of NaCl/L.NOTE 3Other dyes may be used for this test if they have been shownto give equivalent results, for example, form stable solutions, arerelatively insensitive to pH changes in the pH 4 to 8 range; gi
38、vemeasurable absorbance values in a similar concentration range, etc. Ifanother dye is used, a suitable wavelength must be determined formeasurement.17. Procedure17.1 Install the test equipment in accordance with 8.1through 6.3 of Test Methods D 4194.17.2 Start up and operate the test system in acco
39、rdance withSection 8 of Test Methods D 4194.17.3 Data Acquisition:17.3.1 Allow the system to equilibrate for 30 min whilemaintaining constant flow, pressure, and temperature condi-tions. At the end of this period, take a 100-mL sample of thefeed and permeate. Record the flows, pressures, and conduc-
40、tivities of the feed, concentrate, and permeate streams as wellas the permeate temperature.17.3.2 Using dilutions where necessary, measure the absor-bance of the feed and permeate samples against a water blankwith a filter photometer or spectrophotometer at 590 nm.Alternatively, compare the permeate
41、 color intensity with suit-able dilutions of the feed using Nessler tubes.17.4 Shutdown ProcedureThoroughly flush the devicewith water to remove all traces of the dye. Use the highestrecommended concentrate flow rate at 350 kPa (50 psig) feedpressure.After flushing, allow the pressure to reach zero
42、beforedisconnecting the RO or NF device or carrying out mainte-nance on the piping system. Take care to ensure that themembranes are kept wet at all times and are properly sanitizedor winterized, or both, (based on suppliers recommendations)for long-term storage (more than 5 days).18. Calculation18.
43、1 Compute flows, conversions, salt passage, and rejec-tion in accordance with Section 18 of Test Methods D 4194.Dye passage, % determined photometrically!5 Ap/ AF3 DF3 100where:Ap= absorbance of permeate of 590 nm,AF= absorbance of diluted feed at 590 nm, andDF= dilution factor for feed.18.2 The dye
44、 passage can be determined directly by visualcomparison of the permeate with appropriate dilutions of thefeed in Nessler tubes and expressed as a percent of the feed.18.3 A leak is diagnosed if the percent dye passage isgreater than 0.5 %.19. Keywords19.1 dye test; leaks; nanofiltration; O-ring test
45、; reverseosmosis; tubesheet leak test; vacuum testASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent right
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48、ou shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).D3923083
