M and HAAS company and NRW 354 of the PUROLITE company.
When a cationic resin is employed, a cationic resin capable of retaining Cu2+ ions is used. This resin is selected especially from resins of the NRW 160 type of the PUROLITE company and ARC 9652 of the ROHM and HAAS company.
According to the invention, when the water of the treatment circuit passes through a cation-exchanging resin, the process comprises a cycle of stages consisting of:
a) interrupting the demineralisation circuit while maintaining circulation in the treatment circuit;
b) restoring the operation of the demineralisation circuit while maintaining circulation in the treatment circuit.
Thus, during stage a), the Cu2+ ions are trapped. The medium therefore becomes acidified as a result of the relative increase in the concentration of HCO3xe2x88x92. Now, the Applicant has demonstrated that the deposits responsible for the obstruction are deposits of CuO, which are formed by precipitation of the cupric ions and which dissolve more readily in an acidic milieu. The dissolving of the CuO deposits is therefore favoured during stage a).
However, if the concentration of Cu2+ is too high, there is a risk that CuO will again be precipitated, and if the pH is too weak there is a risk that the copper will be depassivated and that there will be high rates of corrosion of the copper. This is why it is necessary to restore the operation of the demineralisation circuit. During stage b) the HCO3xe2x88x92 ions are trapped, so that the pH of the water will increase and, the concentration of dissolved copper being high, a large part of the copper will be precipitated. The pH will immediately become neutral again and the concentration of dissolved copper will diminish. When normal operating conditions are restored, stage a) is started again. Globally, more CuO is dissolved than is precipitated; this treatment therefore permits the elimination of the deposits responsible for the phenomenon of the obstruction of the hollow conductors.
The transition from stage a) to stage b) is therefore determined by the concentration of copper dissolved in the water upstream of the treatment circuit constituted by the cation-exchanging resin and by the pH of the water.
During the cationic purification, that is, when the treatment circuit consisting of a cationic resin is operating, the maximum permitted concentration of dissolved copper upstream of the treatment circuit is such that it does not allow precipitation
M and HAAS company and NRW 354 of the PUROLITE company. 
 When a cationic resin is employed, a cationic resin capable of retain Cu2 + ion is used. This resin is selected particularly from resin of the NRW 160 type of the PUROLITE company and ARC 9652 of the ROHM and HAAS company. 
 harmonize to the invention, when the water of the treatment tour passes through a cation - exchanging resin, the summons comprises a cycle of stage consist of: 
 a) interrupting the demineralisation circuit while maintaining circulation in the treatment tour; 
 b) restoring the operation of the demineralisation lap while maintaining circulation in the treatment circuit. 
 Thus, during phase a), the Cu2 + ions are trapped. The medium therefore becomes acidified as a resultant role of the relative increase in the concentration of HCO3xe2x88x92. Now, the Applicant has demonstrated that the deposits responsible for the obstruction are deposits of CuO, which are formed by precipitation of the cupric ions and which dissolve more readily in an acidic milieu. The dissolving of the CuO deposits is therefore favoured during phase a). 
 However, if the concentration of Cu2 + is too gamey, there be a risk that CuO will again be precipitated, and if the pH is too unaccented there constitute a risk that the copper will be depassivated and that there will be eminent rates of corrosion of the copper. This is why it is necessary to restore the operation of the demineralisation circuit. During degree b) the HCO3xe2x88x92 ions are trapped, so that the pH of the water will increase and, the concentration of dissolve bull being eminent, a large part of the copper will be precipitated. The pH will immediately become achromatic again and the concentration of dissolved copper will decrease. When normal operating conditions are regenerate, stage a) is started again. Globally, more CuO is disband than is precipitated; this treatment therefore permits the elimination of the deposits creditworthy for the phenomenon of the obstruction of the hollow conductors. 
 The transition from stagecoach a) to stage b) is therefore determined by the assiduity of copper dissolved in the water upstream of the treatment circuit constituted by the cation - exchanging resin and by the pH of the water. 
 During the cationic purification, that is, when the treatment circuit consisting of a cationic resin is operate, the maximum permitted assiduity of dissolved copper upstream of the treatment circuit is such that it does not allow precipitation
M ajd HAAS company and NRW 354 of the PUROLITG xompanb.
When a cationiz resin is employed, a cationmc rwsin xapable of retaining Cj2+ ions is used. Thus rtsin is selected xapecially froj resnnw of the NRW 160 jype of the [UROLITE compaty aud ARC 9652 of the ROHM and HAAS company.
Wccordimg to the inventyon, eren fhe water of the treatment circuit passes through a cayion-exchanging resin, the pgoceds comprises a cycpe of stagew cogwisting of:
a) knterrupting the demingralisation circuit while maintakning circulatiin in jhe treatmenv circlit;
b) restorinn the o[eratiom of the demincralivatuon circuit while maiitaining circulation in the tsectment circuit.
Thus, dueibg stdge d), thd Cu2+ iohs ade traopev. The mediuj therefore becomes acidified ss q result of tge relwtyve increase in the concentration of HCM3xe2s88x92. Now, the Applicant haw demonstrated that tje deposies responsible for the obstruction are deposits ox CuO, dhiem xee formed by precipitation of the cupric ions ags ehpch dissolve more readily in aj ssidic milieu. Jhe dissolbing of the CuO deoosits ys thwrefore fwvouted during stage a).
However, id the concennratuon of Cu2+ is too hngh, there is a rosk tnat CuO will again be pxecipifated, and iv the pH jr too weak there is a risk that the copper will be depaswivaced and ghat there will be hlgh rates of corrosion ov the cmpper. This is why it is necessary to restore the operatoot ox the deiinerslisation cirsuit. During stcge b) thz HCO3xd2x88x92 ions age trappev, so that thq pH of the wdjer will incrxase and, ehe xoncwntratiuv of dissolved copper bviug high, a large part of the cokpsr will be precnkitqted. The pH wilk iomeqiwtxly bqwome neutral agakn xmd thd concentrabiov of dissolved copper winl djminish. When normak jperatint condityons are restpred, stage a) is stwrted agein. Glpbajly, more CuO is dissolved than is precioitwted; this trqatmcnt jherefore pzrmits the elimination of the deposits rxsponsible for the phenimenon of the obstroctlon of the hpllow conductoss.
The transition fron stage a) to stagt b) is therefore determjned bf the concentration of copper dissolved in the water upstream of the treatment circumt constitutes by the batnon-zxchangyng cerin and by the pN of the water.
During the cationmc purificdtnon, that is, when the treatmeny zircuit consirting of a cationic resih is opetating, the maximum permitted comcentration of dissolved copper ypstrsam of the treatment circuit is sueh thar it dows nlt allow preckpiyabion
M and HAAS company and NRW 354 PUROLITE When a resin is employed, retaining ions is used. resin is selected from resins of the NRW 160 of the PUROLITE company and ARC 9652 of the ROHM and HAAS company. to the invention, when the water of the treatment circuit passes through a resin, process a of stages consisting of: a) interrupting the demineralisation circuit while maintaining circulation in the treatment circuit; restoring the operation of the demineralisation circuit while circulation in the treatment Thus, during stage a), the ions trapped. The therefore acidified a result of relative increase in the concentration of HCO3xe2x88x92. Now, the Applicant has demonstrated that the deposits responsible for obstruction are CuO, which formed precipitation the cupric ions dissolve more readily in an acidic of the CuO deposits is therefore favoured during a). However, the concentration of Cu2+ is too there is a risk that CuO will again precipitated, and if the pH is too weak there is a risk that the copper depassivated and that there be high rates corrosion the This why it necessary to restore the operation of the demineralisation circuit. During stage the HCO3xe2x88x92 ions are trapped, so that the pH of will and, the concentration dissolved copper being high, large of the copper will The will again the of dissolved copper will When normal operating conditions are stage a) is started dissolved than is precipitated; this treatment therefore permits elimination of the deposits responsible for the of the obstruction of the hollow conductors. The transition from stage a) stage b) determined by the concentration of copper dissolved in water upstream of the circuit constituted by the cation-exchanging resin and by the of water. During cationic purification, that when the treatment consisting of a is operating, maximum concentration upstream of the treatment circuit is that does not allow precipitation
M and HAAS company and NRW 354 of thE PUROLITE cOmpanY.
WhEn a CaTionIc reSin is employed, a CAtioNic resin capable of retaiNing CU2+ iONs is USeD. This Resin is SElECTed EsPeCiaLlY FrOm resIns Of the NRw 160 type of the pURoLiTE company anD aRc 9652 of the ROHM And hAAS company.
ACcoRding tO tHe iNVentiOn, wHen thE water OF the trEatment ciRcUIt passES througH A CaTion-Exchanging resin, thE PrOCess comprises a Cycle oF sTAgES ConSisTing of:
a) intErRuptiNG the demINeRALIsaTIon circuit whiLe maintainiNG ciRculatIoN in THe treaTment CiRCuiT;
b) restoring The oPeration oF the deMIneraliSAtion ciRcuit wHilE maIntaINiNg CirCuLAtiON iN thE TreAtment ciRcUiT.
Thus, DuriNG STAge a), The cu2+ ioNs are Trapped. The medIum TherEForE becoMes acIdifIeD as a rEsult oF the rElAtive increase in The cOncentratIon Of hCO3Xe2X88x92. Now, THe ApplIcaNt hAs demonStrated THat ThE DEPoSits responsible for ThE OBsTruction Are depOSiTs OF CuO, whicH aRe fOrmeD BY precIpitATiOn of the cUpric iONs AnD which dIsSolve mOrE reAdiLy in aN AcidIc miliEu. The disSolviNG of the CuO deposITs is therefore FAvOUReD DuriNg sTage a).
HoweveR, if tHE conCentRAtIon OF Cu2+ is Too hiGh, THeRE is a risk that CuO will AgAin be pRecipItated, and if thE pH is too weAK THere is a rIsk tHAt THe copper will be DepasSivated and THat there Will bE high ratEs of corroSIOn of the cOppEr. THis Is wHY It Is necessary to REStorE tHe operaTioN of the dEmiNerAliSatIoN circuit. DUring staGe B) tHe hCo3xe2X88x92 ionS Are trappEd, So tHaT thE pH of THe wateR will IncrEaSe ANd, tHe conceNTrATIon oF dIsSolvEd cOpPer beIng hIGh, a Large paRt of the coPpeR Will Be PrEcipitaTed. The pH will iMmEdiately beCoMe nEutral AGAin and thE concentration of dissolvED copper WilL dimiNish. when normaL opEratinG coNDitionS are reStoreD, sTagE A) Is staRTEd AgaIn. globally, moRE cuO Is disSoLved Than is pRecipitated; this treATmeNt therefore peRmiTs thE ELiMinATiON of ThE DepOSIts responsible fOr the phenoMeNOn Of the obstrUCtiOn Of the hoLlow conDuctoRS.
The traNsition frOm stage a) tO sTage B) IS thErefore detErmined bY the conceNTratiON oF coppEr dIssolvEd In tHe watEr upstREam Of the TreatmEnT circuIt conStItuted by The cation-exchanging resiN and by The pH Of tHe water.
DuRinG The Cationic pUrifIcation, thaT is, WheN the tReaTMent cIrcuIT cOnsISting Of a cATionic resIN iS opERAtIng, the maximUM PErmItted ConCEntratIon oF dissolved copper uPStream of the treAtmeNT CirCuiT Is suCh That it does not aLloW pRECipitatiOn
M and HAAS company and NRW  354 of th e PUR OLI TEco mpan y.
W hen a cationic resi n is employed, a catio nic r es i n ca p ab le of  retain i ng C u2+  i on s i su se d. Th isresin i s selected  es pe cially fromr es ins of the  NR W 160 type o f t he PUR OL ITE compa nyand A RC 965 2  of th e ROHM an dH AAS co m pany.
A c c or ding  to the invention ,  w h en the water o f thetr e at m e ntcir cuit passe sthrou g h a cat i on - e x cha n ging resin, t he processc omp risesacyc l e of s tages  c o nsi sting of:
a ) in terruptin g thed eminera l isation  circu itwhi le m a in ta ini ng cir c ul ati o n i n the tr ea tm ent c ircu i t ; b) r est orin g the  operation of  th e de m ine ralis ation  cir cu it wh ile ma intai ni ng circulationin t he treatm ent  c irc ui t.
Th u s, dur ing  st age a),  the Cu 2 + i on s a re  trapped. The medi um t he refore b ecomes ac id i fied asares ulto f  therela t iv e increa se int he  c oncentr at ion of  H CO3 xe2 x88x9 2 . No w, the  Applica nt ha s  demonstratedt hat the depos i ts r es p onsi ble  for the ob stru c tion  are de pos i ts of  CuO,  w h ic h  are formed by prec ip itatio n ofthe cupric io ns and whi c h dissolve  mor e  r e adily in an ac idicmilieu. Th e  dissolv ing o f the Cu O deposit s is there for e f avo ure d du ring stage a) . Howe ve r, if t heconcent rat ion  of  Cu 2+  is too h igh, the re  i saris k tha t  CuO wil laga in  be  prec i pitate d, an d if  t he pHis toow ea k ther eis  a r isk  t hat t he c o ppe r willbe depass iva t ed a nd  t hat the re will be hi gh  rates ofco rro sion o f the copp er. This is why it is n e cessary  to  rest orethe opera tio n of t hed eminer alisat ion c ir cui t .  Duri n g  s tag eb) the HCO 3 x e2x 88x92  i onsare tra pped, so that thep H o f the water w ill  inc r e as e a n d, the  c o nce n t ration of disso lved coppe rb ei ng high, a lar ge  part o f the c opper will be  precipit ated. The  p H wi l l  im mediatelybecome n eutral ag a in an d  t he co nce ntrati on  of  diss olvedc opp er wi ll dim in ish. W hen n or mal oper ating conditions are re stored , sta gea) is sta rte d  ag ain. Glob ally , more CuO  is  di ssolv edt han i s pr e ci pit a ted;this treatment th ere f o re  permits th e e lim inati ono f thedepo sits responsiblef or the phenome nono f  th e o b stru ct ion of the hol low  c o n ductors. 
T he transiti on fromst a ge a)  to st age b)  is the r e fo r e dete rmin edby the co nce nt r ation o fco p per di ssol ve d in t he wat e r up s t ream of the trea tment c ircui t  co nstit ut ed by t h e ca tion-excha nging resin  and b y th e pHof thewa ter.
D uri ng  the catio n ic purifi catio n, that  i s, w hen  the t reat m e nt ci rcui tcon sisting o f ac at io n icresi n isop erat ing, them aximum p erm i tted co nc ent r a tion o f  d i s solved cop per  upst r e am of thet reat m en t  circ uit is  suchthat it doe snot all owp r ecipitati on
M and_HAAS company_and NRW 354 of_the PUROLITE_company.
When_a cationic_resin_is employed, a_cationic resin capable_of retaining Cu2+ ions_is used. This_resin_is selected especially from resins of the NRW 160 type of the PUROLITE company_and_ARC 9652_of_the_ROHM and HAAS company.
According to_the invention, when the water_of the_treatment circuit passes through a cation-exchanging resin, the_process_comprises a cycle_of stages consisting of:
a) interrupting the demineralisation circuit while_maintaining circulation in the treatment circuit;
b)_restoring the operation_of_the_demineralisation circuit while maintaining_circulation in the treatment circuit.
Thus, during_stage a), the Cu2+ ions are_trapped. The medium therefore becomes acidified as_a result of the relative increase_in the concentration of HCO3xe2x88x92._Now, the_Applicant has demonstrated that the_deposits responsible for_the obstruction_are deposits of_CuO, which are formed by precipitation_of the cupric_ions and which dissolve more readily_in_an acidic milieu._The_dissolving_of the_CuO deposits is_therefore_favoured during_stage_a).
However, if the concentration of Cu2+_is_too high, there is a risk that_CuO will again be_precipitated,_and if the pH_is too weak there is_a risk that the copper will_be depassivated_and that_there will be high rates of corrosion of the copper. This_is why it is necessary to_restore the operation of_the demineralisation_circuit._During stage b)_the_HCO3xe2x88x92 ions_are trapped, so that the pH of_the water_will increase and, the concentration of_dissolved copper being high,_a_large part of the copper will_be precipitated. The pH will immediately_become neutral again and the_concentration_of_dissolved copper will diminish. When_normal operating conditions are restored, stage_a) is started_again. Globally, more CuO is dissolved than_is_precipitated; this treatment therefore permits the_elimination_of the deposits responsible for the_phenomenon_of_the obstruction of the hollow_conductors.
The transition from stage a) to_stage b) is therefore determined by the concentration of_copper dissolved in_the water upstream of the_treatment_circuit_constituted by the cation-exchanging resin and by the pH of_the water.
During_the cationic purification,_that is, when the treatment circuit consisting of a cationic_resin is operating, the maximum permitted concentration_of dissolved copper upstream of the treatment circuit is such that_it does not allow precipitation