HRP20030414A2 - Cathodic protection of heat exchanger tubes by means of mobile sacrificial anodes - Google Patents
Cathodic protection of heat exchanger tubes by means of mobile sacrificial anodes Download PDFInfo
- Publication number
- HRP20030414A2 HRP20030414A2 HR20030414A HRP20030414A HRP20030414A2 HR P20030414 A2 HRP20030414 A2 HR P20030414A2 HR 20030414 A HR20030414 A HR 20030414A HR P20030414 A HRP20030414 A HR P20030414A HR P20030414 A2 HRP20030414 A2 HR P20030414A2
- Authority
- HR
- Croatia
- Prior art keywords
- heat exchanger
- movable
- exchanger tubes
- metal
- sacrificial
- Prior art date
Links
- 238000004210 cathodic protection Methods 0.000 title claims description 12
- 229910052751 metal Inorganic materials 0.000 claims description 26
- 238000000034 method Methods 0.000 claims description 19
- 238000005260 corrosion Methods 0.000 claims description 14
- 239000007769 metal material Substances 0.000 claims description 8
- 239000002245 particle Substances 0.000 claims description 6
- 239000000498 cooling water Substances 0.000 claims description 5
- 239000000463 material Substances 0.000 claims description 4
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 claims description 3
- 229910052725 zinc Inorganic materials 0.000 claims description 3
- 239000011701 zinc Substances 0.000 claims description 3
- 239000002184 metal Substances 0.000 description 17
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 13
- 230000007797 corrosion Effects 0.000 description 9
- 239000003990 capacitor Substances 0.000 description 7
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- 229910052760 oxygen Inorganic materials 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- 150000001768 cations Chemical class 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 102220491117 Putative postmeiotic segregation increased 2-like protein 1_C23F_mutation Human genes 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 229920001971 elastomer Polymers 0.000 description 1
- 239000000806 elastomer Substances 0.000 description 1
- 239000003792 electrolyte Substances 0.000 description 1
- 239000002923 metal particle Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 239000011859 microparticle Substances 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 229920002635 polyurethane Polymers 0.000 description 1
- 239000004814 polyurethane Substances 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 239000013535 sea water Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
- C23F13/00—Inhibiting corrosion of metals by anodic or cathodic protection
- C23F13/02—Inhibiting corrosion of metals by anodic or cathodic protection cathodic; Selection of conditions, parameters or procedures for cathodic protection, e.g. of electrical conditions
- C23F13/06—Constructional parts, or assemblies of cathodic-protection apparatus
- C23F13/08—Electrodes specially adapted for inhibiting corrosion by cathodic protection; Manufacture thereof; Conducting electric current thereto
- C23F13/12—Electrodes characterised by the material
- C23F13/14—Material for sacrificial anodes
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
- C23F13/00—Inhibiting corrosion of metals by anodic or cathodic protection
- C23F13/02—Inhibiting corrosion of metals by anodic or cathodic protection cathodic; Selection of conditions, parameters or procedures for cathodic protection, e.g. of electrical conditions
- C23F13/06—Constructional parts, or assemblies of cathodic-protection apparatus
- C23F13/08—Electrodes specially adapted for inhibiting corrosion by cathodic protection; Manufacture thereof; Conducting electric current thereto
- C23F13/10—Electrodes characterised by the structure
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
- C23F13/00—Inhibiting corrosion of metals by anodic or cathodic protection
- C23F13/02—Inhibiting corrosion of metals by anodic or cathodic protection cathodic; Selection of conditions, parameters or procedures for cathodic protection, e.g. of electrical conditions
- C23F13/06—Constructional parts, or assemblies of cathodic-protection apparatus
- C23F13/08—Electrodes specially adapted for inhibiting corrosion by cathodic protection; Manufacture thereof; Conducting electric current thereto
- C23F13/16—Electrodes characterised by the combination of the structure and the material
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
- C23F2213/00—Aspects of inhibiting corrosion of metals by anodic or cathodic protection
- C23F2213/30—Anodic or cathodic protection specially adapted for a specific object
- C23F2213/32—Pipes
Description
Područje tehnike The field of technology
Predmet izuma je postupak katodne zaštite cijevi izmjenjivača topline pomoću pokretnih žrtvovanih anoda. Prema sedmom izdanju Međunarodne klasifikacije patenata izum spada u područja tehnike označena oznakama: The subject of the invention is the method of cathodic protection of heat exchanger tubes using movable sacrificial anodes. According to the seventh edition of the International Classification of Patents, the invention belongs to the fields of technology indicated by the following symbols:
C23F 13/00 - Sprečavanje korozije metala anodnom ili katodnom zaštitom, C23F 13/00 - Prevention of metal corrosion by anodic or cathodic protection,
F28F 19/00 - Sprečavanje nastajanja naslaga ili korozije u izmjenjivačima topline, npr. upotrebom filtara. F28F 19/00 - Preventing the formation of deposits or corrosion in heat exchangers, eg by using filters.
Tehnički problem i stanje tehnike Technical problem and state of the art
Osnovna namjena velikih rashladnih izmjenjivača topline ili kondenzatora u energanama je pretvaranje iskorištene vodene pare u vodu. Glavni dijelovi kondenzatora su prednja i stražnja vodna komora koje su međusobno povezane tisućama izmjenjivačkih cijevi koje mogu biti duge do 12 m. Voda za hlađenje, često morska voda, ulazi u prednju vodnu komoru, prolazi kroz cijevi i izlazi kroz stražnju komoru u odvodni kanal. Vodena para prostujava oko izmjenjivačkih cijevi kroz koje protječe rashladna voda pri čemu se hladi i kondenzira u vodu. Izmjenjivači topline uobičajeno su zaštićeni od korozije katodnom zaštitom. Osnovni problem antikorozijske zaštite izmjenjivača topline je što električna struja ne doseže površine u unutrašnjosti dugačkih izmjenjivačkih cijevi te njihova katodna zaštita nije učinkovita. Stoga se cijevi izmenjivača topline izrađuju od skupih nehrđajućih materijala kao što je CuZn20Al2F34. Međutim, čak i cijevi izrađene od nehrđajućih materijala korodiraju. Korozija počinje s unutrašnje strane cijevi i napreduje prema vanjskoj sve do pojave rupa. Tada je potrebno zaustaviti cijelo postrojenje i izmijeniti perforirane cijevi. The basic purpose of large cooling heat exchangers or condensers in power plants is to convert used water vapor into water. The main parts of the condenser are the front and rear water chambers, which are interconnected by thousands of exchange tubes that can be up to 12 m long. Cooling water, often seawater, enters the front water chamber, passes through the tubes, and exits through the rear chamber into the drainage channel. The water vapor circulates around the exchanger tubes through which the cooling water flows, where it cools and condenses into water. Heat exchangers are usually protected from corrosion by cathodic protection. The basic problem of anti-corrosion protection of heat exchangers is that the electric current does not reach the surfaces inside the long exchanger tubes and their cathodic protection is not effective. Therefore, heat exchanger tubes are made of expensive stainless materials such as CuZn20Al2F34. However, even pipes made of stainless materials corrode. Corrosion starts from the inside of the pipe and progresses towards the outside until holes appear. Then it is necessary to stop the entire plant and replace the perforated pipes.
U stručnoj i patentnoj literaturi nema opisanog tehničkog rješenja antikorozijske zaštite cijevi izmjenjivača topline primjenom pokretnih žrtvovanih anoda koje je predmet ovog izuma. In the professional and patent literature, there is no technical solution described for anti-corrosion protection of heat exchanger pipes using movable sacrificial anodes, which is the subject of this invention.
Bit izuma The essence of invention
Rješenje antikorozijske zaštite izmjenjivačkih cijevi u kondenzatorima prema izumu temelji se na primjeni pokretnih žrtvovanih anoda. Pokretne žrtvovane anode izrađene su od spužvastih kuglica kakve se koriste za čišćenje unutrašnjih površina cijevi, npr. u Taprogge uređajima, u koje su ugrađeni šiljci, slični elementi ili čestice od metalnog materijala koji ima niži elektrodni potencijal nego metal od kojeg su izrađene cijevi izmjenjivača topline. Spužvaste kuglice s česticama metalnog materijala na površini ubacuju se u vodu za hlađenje koja prolazi kroz cijevi izmjenjivača topline. The solution of anti-corrosion protection of exchanger tubes in capacitors according to the invention is based on the application of movable sacrificial anodes. Movable sacrificial anodes are made of sponge balls such as those used to clean the inner surfaces of pipes, for example in Taprogge devices, in which spikes, similar elements or particles of a metal material that has a lower electrode potential than the metal of which the heat exchanger pipes are made are embedded. . Sponge balls with particles of metallic material on the surface are inserted into the cooling water that passes through the heat exchanger tubes.
Pri prolasku kroz cijevi izmjenjivača topline između metalnih elemenata u kuglicama i cijevi izmjenjivača topline odvija se elektrokemijski proces uslijed njihovog međusobnog stalnog kontakta. U tom procesu metal u kuglicama djeluje kao pokretna žrtvovana anoda koja štiti unutrašnje površine cijevi koje imaju ulogu katode. Metalni elementi postupno se troše te je potrebno periodički mijenjati spužvaste kuglice s česticama metalnog materijala. Primjenom ovakvog načina antikorozijske zaštite korozija cijevi izmjenjivača topline više ne predstavlja problem što omogućava izradu cijevi izmjenjivača topline od jeftinijih materijala. When passing through the heat exchanger pipes, an electrochemical process takes place between the metal elements in the balls and the heat exchanger pipes due to their constant mutual contact. In this process, the metal in the balls acts as a movable sacrificial anode that protects the inner surfaces of the tubes that act as the cathode. Metal elements gradually wear out and it is necessary to periodically change the sponge balls with particles of metal material. By applying this method of anti-corrosion protection, the corrosion of the heat exchanger tubes is no longer a problem, which enables the production of heat exchanger tubes from cheaper materials.
Opisi slika Image descriptions
Slika 1 prikazuje članove elektrokemijskog procesa u katodno nezaštićenoj cijevi izmjenjivača topline. Figure 1 shows the members of the electrochemical process in a cathodically unprotected heat exchanger tube.
Slika 2 prikazuje članove elektrokemijskog procesa u katodno zaštićenoj cijevi izmjenjivača topline. Figure 2 shows the members of the electrochemical process in a cathodically protected heat exchanger tube.
Slika 3 prikazuje radijalni presjek pokretne žrtvovane anode s metalnim elementima. Figure 3 shows a radial section of a movable sacrificial anode with metal elements.
Slika 4 prikazuje izmjenjivač topline s pokretnim žrtvovanim anodama u cijevima izmjenjivača topline. Figure 4 shows a heat exchanger with movable sacrificial anodes in the heat exchanger tubes.
Opis izvedbe i primjene Description of performance and application
Kroz kondenzatorske cijevi bez katodne zaštite i sa katodnom zaštitom teče aerirana voda, tj. voda, H2O, koja sadrži kisik, O2,upijen iz zraka s kojim je prethodno bila u kontaktu. Aerated water flows through capacitor tubes without cathodic protection and with cathodic protection, i.e. water, H2O, which contains oxygen, O2, absorbed from the air with which it was previously in contact.
U kondenzatorskoj cijevi bez katodne zaštite prikazanoj na slici 1 konstrukcijski metal M1 kondenzatorske cijevi korodira djelovanjem lokalnih galvanskih članaka, tzv. korozijskih mikročlanaka. Na unutarnjoj površini cijevi odvija se istovremeno anodni proces trošenja metala ionizacijom i katodni proces redukcije kisika. Oba procesa izazivaju njezinu koroziju. Pojedina mjesta na unutarnjoj površini kondenzatorske cijevi načinjenoj od konstrukcijskog metala M1 ponašaju se kao lokalne anode A a pojedina kao lokalne katode K. In the capacitor tube without cathodic protection shown in Figure 1, the structural metal M1 of the capacitor tube corrodes due to the action of local galvanic articles, the so-called corrosion microparticles. On the inner surface of the tube, the anodic process of metal consumption by ionization and the cathodic process of oxygen reduction take place simultaneously. Both processes cause its corrosion. Some places on the inner surface of the capacitor tube made of structural metal M1 act as local anodes A and some as local cathodes K.
Anodni proces odvija se prema obrascu: The anode process takes place according to the pattern:
[image] [image]
Katodni proces odvija se prema obrascu: The cathodic process takes place according to the pattern:
[image] [image]
Ukupni korozijski proces odvija se prema obrascu: The overall corrosion process takes place according to the pattern:
[image] [image]
gdje su: z1 – broj elementarnih naboja kationa M1z1+ where: z1 – number of elementary charges of cation M1z1+
e- – elektron. e- – electron.
U kondenzatorskoj cijevi K s katodnom zaštitom prikazanoj na slici 2 odvija se elektrokemijski proces djelovanjem galvanskog makročlanka. Konstrukcijski metal M1 kondenzatorske cijevi K u kontaktu je s metalnim elementom A žrtvovane anode SA koji je načinjen od metala M2 nižeg elektrodnog potencijala od elektrodnog potencijala što ga ima konstrukcijski metal M1. Cink je jedan od ekonomski najprikladnijih metala za izradu metalnih elemenata A žrtvovane anode SA. Anodni proces trošenja ionizacijom ograničen je na kontaktni metal M2 jer je on snažniji donor elektrona od konstrukcijskog metala M1. Katodni proces redukcije kisika odvija se isključivo s unutarnje strane cijevi, čime je ona katodno zaštićena. In the capacitor tube K with cathodic protection shown in Figure 2, an electrochemical process takes place through the action of a galvanic macrocell. The structural metal M1 of the capacitor tube K is in contact with the metal element A of the sacrificial anode SA, which is made of metal M2 of a lower electrode potential than the electrode potential of the structural metal M1. Zinc is one of the most economically suitable metals for the production of metal elements A of the sacrificial anode SA. The anodic wear process by ionization is limited to the contact metal M2 because it is a stronger electron donor than the construction metal M1. The cathodic process of oxygen reduction takes place exclusively on the inside of the tube, which is why it is cathodically protected.
Anodni proces odvija se prema obrascu: The anode process takes place according to the pattern:
[image] [image]
Katodni proces odvija se prema obrascu: The cathodic process takes place according to the pattern:
[image] [image]
gdje je: z2 – broj elementarnih naboja kationa M2z2+ . where: z2 – the number of elementary charges of the cation M2z2+.
Konstrukcijska izvedba jedne pokretne žrtvovane anode prikazana je na slici 3. The design of a movable sacrificial anode is shown in Figure 3.
Pokretna žrtvovana anoda ima oblik kuglice izrađene od spužvastog polimernog, na primjer poliuretanskog, elastomera 1. The movable sacrificial anode has the form of a ball made of spongy polymer, for example polyurethane, elastomer 1.
U kuglicu su po cijelom oplošju ugrađeni šiljci 2, slični elementi ili čestice od metalnog materijala koji ima niži elektrodni potencijal nego metal cijevi koji treba zaštititi. Metalni šiljci mogu biti, na primjer, izrađeni od cinka koji je i dovoljno mekan da ne oštećuje površinu cijevi. Šiljci, slični elementi ili čestice postavljaju se u kalup za izradu spužvastih kuglica i nakon što se tijelo kuglice skruti postaju sastavni dijelovi kuglice. Spikes 2, similar elements or particles made of a metal material that has a lower electrode potential than the metal of the pipe that needs to be protected are embedded in the ball. Metal spikes can be, for example, made of zinc, which is soft enough not to damage the surface of the pipe. Spikes, similar elements or particles are placed in a mold for making sponge balls and after the body of the ball solidifies, they become integral parts of the ball.
Primjena pokretnih žrtvovanih anoda u izmjenjivaču topline prikazana je na slici 4. Pokretne žrtvovane anode u obliku spužvastih kuglica s metalnim šiljcima prikazane su na detalju A slike 4 a pokretne žrtvovane anode u obliku spužvastih kuglica s metalnim česticama prikazane su na detalju B slike 4. The application of movable sacrificial anodes in the heat exchanger is shown in Figure 4. The movable sacrificial anodes in the form of spongy balls with metal spikes are shown in detail A of Fig. 4 and the movable sacrificial anodes in the form of spongy balls with metal particles are shown in detail B of Fig. 4.
Pokretne žrtvovane anode SA ubacuju se u vodu za hlađenje H2O koja iz prednje vodne komore PVK ulazi u cijevi C izmjenjivača a zatim kroz stražnju vodnu SVK komoru izlazi iz izmjenjivača topline. Pri prolasku pojedine kuglice kroz cijev uvijek je nekoliko metalnih elemenata u kontaktu s unutrašnjom površinom cijevi. Budući da je neizbježno prisutan i elektrolit tj. morska ili obična voda stvara se galvanski članak u kojem je donor elektrona metal nižeg elektrodnog potencijala tj. metalni elementi ugrađeni u spužvastu kuglicu. Time oni štite cijevi od korozije a sami postupno gube masu. Kuglice koje na taj način postanu neučinkovite treba zamijeniti novima. The movable sacrificial anodes SA are inserted into the H2O cooling water, which enters the pipes of the C exchanger from the front water chamber PVK and then exits the heat exchanger through the rear water chamber SVK. When a single ball passes through the tube, several metal elements are always in contact with the inner surface of the tube. Since an electrolyte is inevitably present, i.e. sea or ordinary water, a galvanic article is created in which the electron donor is a metal of a lower electrode potential, i.e. metal elements embedded in a spongy ball. In this way, they protect the pipes from corrosion and they themselves gradually lose mass. Balls that become ineffective in this way should be replaced with new ones.
Claims (4)
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| HR20030414A HRP20030414A2 (en) | 2003-05-22 | 2003-05-22 | Cathodic protection of heat exchanger tubes by means of mobile sacrificial anodes |
| PCT/HR2004/000013 WO2004104270A1 (en) | 2003-05-22 | 2004-05-05 | Cathodic protection of heat exchanger tubes by means of mobile sacrificial anodes |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| HR20030414A HRP20030414A2 (en) | 2003-05-22 | 2003-05-22 | Cathodic protection of heat exchanger tubes by means of mobile sacrificial anodes |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| HRP20030414A2 true HRP20030414A2 (en) | 2005-04-30 |
Family
ID=33462990
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| HR20030414A HRP20030414A2 (en) | 2003-05-22 | 2003-05-22 | Cathodic protection of heat exchanger tubes by means of mobile sacrificial anodes |
Country Status (2)
| Country | Link |
|---|---|
| HR (1) | HRP20030414A2 (en) |
| WO (1) | WO2004104270A1 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9738551B2 (en) | 2012-04-18 | 2017-08-22 | Westinghouse Electric Company Llc | Additives for heat exchanger deposit removal in a wet layup condition |
| US9334579B2 (en) | 2013-10-29 | 2016-05-10 | Westinghouse Electric Company Llc | Targeted heat exchanger deposit removal by combined dissolution and mechanical removal |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4822570B1 (en) * | 1970-12-12 | 1973-07-06 |
-
2003
- 2003-05-22 HR HR20030414A patent/HRP20030414A2/en not_active Application Discontinuation
-
2004
- 2004-05-05 WO PCT/HR2004/000013 patent/WO2004104270A1/en active Application Filing
Also Published As
| Publication number | Publication date |
|---|---|
| WO2004104270A1 (en) | 2004-12-02 |
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| Date | Code | Title | Description |
|---|---|---|---|
| A1OB | Publication of a patent application | ||
| OBST | Application withdrawn |