1、Designation: D 3923 94 (Reapproved 2003)e1Standard Practices forDetecting Leaks in Reverse Osmosis Devices1This 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
2、 revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.e1NOTEAn editorial change was made in 10.1 in June 2003.1. Scope1.1 These practices cover detecting leaks in which there is adirect c
3、ommunication between the feed or concentrate, or both,and the permeate. Several types of leaks are possible with thevarious configurations of reverse-osmosis 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 t
4、he tubesheet and past the tube 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
5、 interconnectors.1.2.3 With tubular 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 Devices6to9Practice BVacuum T
6、est for Spiral Wound Devices 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 hea
7、lth practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:D 1129 Terminology Relating to Water2D 1193 Specification for Reagent Water2D 4194 Test Methods for Operating Characteristics of Re-verse Osmosis Devices3E60 Practice for M
8、olecular Absorption SpectrophotometricMethods for Chemical Analysis of Metals, Ores, andRelated Materials4E 275 Practice for Describing and Measuring Performanceof Ultraviolet, Visible, and Near Infrared Spectrophotom-eters53. Terminology3.1 For definitions of terms used in these practices, refer to
9、Terminology D 1129.3.2 For descriptions of terms relating to reverse osmosis,refer to Test Methods D 4194.3.3 Definitions of Terms Specific to This Standard:3.3.1 leakbypassing of the intact membrane from thefeed side to the permeate side.4. Summary of Practice4.1 The hollow-fiber device being teste
10、d 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 detected visually by inspection.5. Significance and Use5.1 These practices may
11、be used to determine whether areverse-osmosis device is free of leaks if the mechanicalintegrity of the device is to be confirmed. They may also beused to detect leaks in reverse-osmosis devices whose operat-ing performance indicates a possible leak. These practices maybe used for either new or used
12、 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/block while securing thefiber bundle from movement. This allow
13、s visual observationduring low-pressure operation with the fiber bundle retained inits original position.1These 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
14、June 10, 2003. Published July 2003. Originallyapproved in 1980. Last previous edition approved in 1998 as D 3923 94 (1998).2Annual Book of ASTM Standards, Vol 11.01.3Annual Book of ASTM Standards, Vol 11.02.4Annual Book of ASTM Standards, Vol 03.05.5Annual Book of ASTM Standards, Vol 03.06.1Copyrigh
15、t ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.7. Purity of Reagents7.1 Reagent grade chemicals shall be used in all tests.Unless otherwise indicated, it is intended that all reagents shallconform to the specifications of the Committee on An
16、alyticalReagents of the American Chemical Society, where suchspecifications are available.6Other grades may be used,provided it is first ascertained that the reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy ofthe determinations.7.2 Unless otherwise indicated, re
17、ferences to water shall beunderstood to mean Type III reagent water conforming toSpecification D 1193.PRACTICE ATUBE SHEET AND O-RING LEAKTEST FOR HOLLOW FIBER DEVICES8. Scope8.1 This practice is applicable to detecting feed or concen-trate leakage, or both, through the tube sheet and past the tubes
18、heet O-ring into the permeate in hollow-fiber devices.9. Procedure9.1 Connect a centrifugal pump with 1.4 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 reverse-osmosis device.9.2 Remove the
19、permeate end plate and auxiliary equipmentin accordance with the suppliers instructions to expose theface of the permeate tube sheet.9.3 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 th
20、e permeate endplate in place.9.4 Place the hollow-fiber device in the horizontal positionand orient the open concentrate 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
21、concentrate line valve topressurize the unit to 350 kPa (50 psig). While standing clearof the tube sheet, start the 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
22、 to determinethe integrity of the tube sheet and tube sheet O-ring.9.5 Examine for leaks by observing the product 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
23、O-ring seal, aforceful spray or stream will be observed. During inspection,rotate the device 180 to examine the lower 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.9.6 Shu
24、tdown Procedure:9.6.1 Shut off the centrifugal pump and allow the pressure toreach zero before disconnecting the reverse-osmosis device.9.6.2 Replace permeate end plate and all auxiliary equip-ment in accordance with the suppliers instructions.9.6.3 Take care to ensure that the membranes are kept we
25、t atall times and are properly sanitized or winterized, or both,(based on suppliers recommendations) for long-term storage(more than 5 days).PRACTICE BVACUUM TEST FOR SPIRAL WOUNDDEVICES10. Scope10.1 This practice is applicable to detecting leaks in spiral-wound reverse-osmosis devices, new or used,
26、 when such leaksare significant enough to prevent the device from holding avacuum. These leaks may be due to a damaged membrane,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.11. Summary of
27、 Practice11.1 The device is evaluated with one end of the permeatecollection tube sealed. A vacuum gage on the other end of thetube is observed. A rapid decay in vacuum indicates a leak.12. Procedure12.1 Seal one end of the permeate collection tube with asuitable leak-tight cap. Connect the other en
28、d of the permeatetube to a vacuum gage and a valved vacuum source.12.2 Evacuate the element to 84 to 101 kPa vacuum (25 to30 in. Hg vacuum). Close the isolation 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/ m
29、in)will indicate the presence of a leak.12.3 Shutdown Procedure:12.3.1 Slowly release the vacuum on the reverse-osmosisdevice and allow the device to reach atmospheric pressurebefore disconnecting.12.3.2 Take care to ensure that the membranes are kept wetat all times and are properly sanitized or wi
30、nterized, or both,for long-term storage (based on suppliers recommendations).PRACTICE CDYE TEST FOR SPIRAL WOUNDANDTUBULAR DEVICES13. Scope13.1 This practice is applicable to detecting leaks in spiralwound or tubular reverse-osmosis devices, new or used, whichare due to lack of or loss of mechanical
31、 integrity.14. Summary of Practice14.1 The practice consists of passing a solution of a dye,known to be rejected by the membrane, through the deviceunder standard conditions as specified in Test Methods D 4194.6Reagent 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 Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,MD.D 3923
33、 94 (2003)e12The concentration of the dye in the permeate relative to that inthe feed is measured either spectrophotometrically or by visualcomparison of the color intensity.Adye passage of greater than0.5 % indicates a leak.15. Apparatus15.1 The test apparatus required is schematically describedin
34、Test Methods D 4194.15.2 Nessler Tubes or PhotometerA set of 50-mLmatched Nessler tubes or a 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 con
35、formto Practice E 275.16. Reagents16.1 Dye Feed Solution (Methyl Violet 2B)Prepare a100-mg/L 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 exampl
36、e, form stable solutions, arerelatively insensitive to pH changes in the pH 4 to 8 range; givemeasurable 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
37、with 8.1through 6.3 of Test Methods D 4194.17.2 Start up and operate the test system in accordance 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 pe
38、riod, take a 100-mL sample of thefeed and permeate. Record the flows, pressures, and conduc-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 blan
39、kwith a filter photometer or spectrophotometer at 590 nm.Alternatively, compare the permeate 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 f
40、low rate at 350 kPa (50 psig) feedpressure.After flushing, allow the pressure to reach zero beforedisconnecting the reverse-osmosis device or carrying outmaintenance on the piping system. Take care to ensure that themembranes are kept wet at all times and are properly sanitizedor winterized, or both
41、, (based on suppliers recommendations)for long-term storage (more than 5 days).18. Calculation18.1 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
42、 of 590 nm,AF= absorbance of diluted feed at 590 nm, andDF= dilution factor for feed.18.2 The dye 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 perce
43、nt dye passage isgreater than 0.5 %.19. Keywords19.1 dye test; leaks; O-ring test; reverse osmosis; tubesheetleak 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
44、are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif no
45、t revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which
46、you may attend. If you feel that your comments have not received a fair hearing you 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).D 3923 94 (2003)e13
