1、ICS 77.060Korrosion der Metalle Verfahren zur Beurteilung der Wirksamkeit von Wasserbehandlungsanlagen zumKorrosionsschutz Teil 4: Technikumsversuche zum Abbau von Korrosionsprodukten aus inkrustiertenRohr-leitungenForewordThis standard has been prepared by Technical Committee Korrosion und Korrosio
2、nsschutz of the Normen-ausschuss Materialprfung (Materials Testing Standards Committee).Ref. No. DIN 50934-4 : 2000-04English price group 05 Sales No. 010503.01DEUTSCHE NORM April 200050934-4Continued on pages 2 and 3. No part of this translation may be reproduced without the prior permission ofDIN
3、Deutsches Institut fr Normung e.V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).Methods of evaluating the effectiveness of watertreatment equipment for corrosion controlPart 4: Laboratory testing of equipment for removing scaleTr
4、anslation by DIN-Sprachendienst.In case of doubt, the German-language original should be consulted as the authoritative text.1 ScopeThis standard specifies a laboratory method of testing the effectiveness of water treatment equipment usedto remove corrosion products (scale) from steel pipes.2 Normat
5、ive referencesThis standard incorporates, by dated or undated reference, provisions from other publications. Thesenormative references are cited at the appropriate places in the text, and the titles of the publications arelisted below. For dated references, subsequent amendments to or revisions of a
6、ny of these publicationsapply to this standard only when incorporated in it by amendment or revision. For undated references, thelatest edition of the publication referred to applies.DIN 2440 Medium-weight threaded steel pipesDIN 19632 Mechanical filters for drinking water systems Requirements and t
7、esting (DVGW Codeof practice)DIN 50905-1 Corrosion testing PrinciplesDIN 50905-2 Corrosion testing Corrosion characteristics of metals subjected to uniform corrosionattackDIN 50930-1 Corrosion behaviour of metallic materials in contact with water GeneralDIN 50931-1 Corrosion testing of drinking wate
8、r distribution systems Determining changes to thecomposition of drinking waterDIN 50934-2 Methods of evaluating the effectiveness of water treatment equipment for corrosioncontrol Equipment for reducing the release of corrosion products into drinking waterDIN EN ISO 8044 Corrosion of metals and allo
9、ys Basic terms and definitions (ISO 8044 : 1999)3 ConceptsFor the purposes of this standard, the concepts defined in DIN EN ISO 8044, DIN 50930-1 and DIN 50934-2apply.In keeping with current practice in standards published by the International Organization for Standardization(ISO), a comma has been
10、used throughout as the decimal marker.Page 2DIN 50934-4 : 2000-044 Principle of methodPressure loss/flow curves are plotted based on measurements taken at the ends of pre-corroded steel pipespecimens before and after water treatment.5 Testing5.1 Test arrangementFour DN 15 steel pipes as in DIN 2440,
11、 each 3 m long, shall be operated using the reagent water specified insubclause 5.2 and the cycle described in table 1 of DIN 50931-1 over a period of six to nine months.The test arrangement shall be as in figure 1. Each test assembly shall comprise not only one of pipes A, B, Cor D, but also a chec
12、k valve, a flow reducer, a flowmeter, a stilling zone, two pressure tappings, and a DIN 19632filter. The stilling zone shall comprise stainless steel or plastic pipes and its length shall be at least equal to10 d. Connections to the pipes shall be made without tapping, and special electrically insul
13、ated connectingelements shall be used. When setting up the assemblies, take care that the pipes under test are facing in thesame direction of flow as they are in practice. Aside from the fittings described above and the pipes under test,only stainless steel pipes shall be used. Fittings shall be of
14、stainless steel or red brass.5.2 Reagent waterThe reagent water shall be used both for the pre-corrosion phase and for the actual test. It may be taken fromany available drinking water system. It should have a pH value below the calcite saturation point, have an anionratio of() ()2SOCl4,324+=-SIKccS
15、and a concentration by mass of oxygen greater than 3 mg/l.5.3 ProcedureTo characterize the extent of corrosion before and after water treatment, remove a 20 cm piece from both endsof each test pipe after the pre-corrosion phase and after the test. Determine the mass per unit area of the surfacecover
16、ed with scale as in DIN 50905-1 and DIN 50905-2.The four test assemblies shall be parallel and operated simultaneously, with two of them being used for theblank test. The operating pressure shall not exceed (2,5 t 0,3) bar. The assemblies shall be operated in accord-ance with table 1 of DIN 50931-1
17、over a period of six months.6 Evaluation of resultsThe effectiveness of the equipment, expressed in mg/l, is given by the increase in flow at a differential pressureof 0,05 bar, expressed in terms of the difference between the measured flow before and after exposure, Q, asshown in equation (1).Effec
18、tiveness = (Qafter Qbefore)m(Qafter Qbefore)o(1)The effectiveness factor, fw, is given by equation (2).()()obeforembeforewQQf+=nesseffective2(2)wheresubscript m means with the water treatment equipment;subscript o means without the water treatment equipment.7 Test reportThe test report shall refer t
19、o this standard and contain the following information:a) place of test;b) duration of test;c) type of pipes tested (cold water, hot water);d) pipe diameters and lengths;e) mass per unit area of the surface covered with scale measured at pipe ends after the pre-corrosion phaseand after testing;f) ana
20、lysis of reagent water as in DIN 50930-1;g) pressure loss/flow curves for each pipe after the pre-corrosion phase and after testing;h) effectiveness;i) effectiveness factor.Page3DIN50934-4:2000-04Figure 1: Test arrangementTest assemblyReagentwaterAssembly for blank testWater treatmentequipmentTest pipe AStilling zonePressure gaugeFlow reducerFlowmeterPneumatic valveTest assemblyAssembly for blank testWater treatmentequipmentTest pipe BTest pipe CTest pipe DPnewPnewPnewPnewPnew
