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
  • C23F13/04—Controlling or regulating desired parameters
• • 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
  • C23F13/22—Monitoring arrangements therefor
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
  • F24H9/00—Details
  • F24H9/40—Arrangements for preventing corrosion
  • F24H9/45—Arrangements for preventing corrosion for preventing galvanic corrosion, e.g. cathodic or electrolytic means
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
  • F24H9/00—Details
  • F24H9/40—Arrangements for preventing corrosion
  • F24H9/45—Arrangements for preventing corrosion for preventing galvanic corrosion, e.g. cathodic or electrolytic means
  • F24H9/455—Arrangements for preventing corrosion for preventing galvanic corrosion, e.g. cathodic or electrolytic means for water heaters
• • 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
  • C23F2213/10—Controlling or regulating parameters
  • C23F2213/11—Controlling or regulating parameters for structures subject to stray currents

Definitions

• the current that is established between the anode and the boiler is periodically varied over time, in its intensity, for a determinate interval, with respect to the normal operating value and, during this variation, the difference in potential that is established between the two poles of the generator is measured.
• the difference in potential measured is compared with a predetermined reference value, corresponding to a known value at which corrosion is impeded; any deviation with respect to this reference value is used to determine a current intensity to be applied between anode and boiler in order to obtain a difference in potential substantially equal to the predetermined reference value.
• protection potential The known difference in potential value, hereafter referred to as protection potential, is determined in a known manner for example with reference to the Pourbaix diagram, or potential/pH diagram, which is a representation of the possible stable conditions at balance of an electrochemical system in aqueous solution.
• This model is used to predict the behavior of a metal material regarding corrosion, in this case referred to iron alloys but also applicable for other metals, although with the adoption of different potentials.
• This method of protection although it guarantees adequate protection against corrosion in the boiler, is a system that is closed upon itself, and is not able to detect possible influences due to factors outside the heating apparatus, such as for example electrostatic loads, electric dispersions or other.
• One purpose of the present invention is to perfect a method to control the functioning of a heating apparatus that is efficient and that allows to increase the working life of the heating apparatus in which it is applied.
• Another purpose of the present invention is to perfect a method that increases the safety of the heating apparatus.
• a method according to the present invention is applied to control the functioning of a heating apparatus in which the heating apparatus comprises:
• the method comprises a step of detecting electric dispersions present in the tank, during which the measurer measures at least one electric quantity and the controller processes the at least one electric quantity in order to determine the presence of electric dispersions, which are to be avoided since they are the cause of the corrosive effect generated on the walls of the tank.
• the detection step provides to detect direct currents of electric dispersion present in the tank.
• the direct currents detection step comprises:
• the controller recognizes a functioning condition that is within the norm, and wherein, if the second value measured is less than the third value of the reference potential, the controller recognizes the presence of electric dispersions deriving from direct currents in the tank.
• the detection step provides to detect alternating currents of electric dispersion.
• the electric quantity measured is an electric current measured.
• the detection step comprises:
• a second step in which the measurer performs a plurality of measurements of the current circulating between the electrode and the tank; - a third step in which the controller verifies whether the values measured of the current circulating between the electrode and the tank remain variable around a balanced current and, in this case, the controller recognizes a condition wherein there is an absence of stray currents;
• the present invention also concerns an electric cathodic protection device to be associated with a heating apparatus comprising a tank containing an electrolytic solution.
• the device comprises an electrode immersed during use in the electrolytic solution, an electric energy generator connected to the electrode and, during use, to the tank, and a controller provided with a measurer configured to measure an electric quantity which is established between the electrode and the tank.
• the controller comprises a processing unit configured to receive the data of the electric quantity detected by the measurer and to process the electric quantity in order to determine the presence of electric dispersions.
• the device also comprises indicators associated to the controller in order to indicate the presence of electric dispersions.
• - fig. 1 is a schematic representation of a heating apparatus that uses a control method according to the present invention
• - fig. 2a is a graph showing the development of potential over time that is applied to the heating apparatus during normal functioning, according to a first form of embodiment
• - fig. 3 a is a graph showing the development of potential over time that is applied to the heating apparatus during normal functioning, according to a second form of embodiment
• - fig. 3b is a graph showing the development of electric currents over time, which is detected in the heating apparatus according to the second form of embodiment and in a functioning condition;
• - fig. 3c is a graph showing the development of electric currents over time, which is detected in the heating apparatus according to the second form of embodiment and in another functioning condition.
• a heating apparatus according to the present invention is indicated in its entirety by the reference number 10 and comprises an electric cathodic protection device 1 1 against corrosion.
• the electric cathodic protection device 1 1 in turn comprises an electrode 13 or anode, an electric energy generator 14 and a controller 16.
• the electrode 13 can comprise a titanium bar, possibly activated with noble materials.
• the current generator 14 is in turn connected to the controller 16 which controls and manages the functioning of the current generator 14, and possibly signals particular functioning conditions of the heating apparatus 10, like the presence of electric dispersions.
• the controller 16 is provided with a measurer 15 that measures at least one electric quantity, configured to detect, for example, the values of current or electric voltage that are established in the electric cathodic protection device 1 1, in this case between the electrode 13 and the tank 12.
• the measurer 15 can be a voltmeter, an amperometer, a wattmeter or simply a device to compare at least one of the electric quantities that are to be detected.
• controller 16 comprises a processing unit 19, provided to process the data detected by the measurer 15 and to signal possible anomalous functioning conditions due to the presence of electric dispersions.
• the controller 16 can be associated to indicators 17, for example luminous indicators, each of which identifies a functioning condition of the heating apparatus 10.
• the protection potential Vp to be established in the electrolytic solution can be generated iteratively by regulating the current supplied by the current generator 14 and detecting with the measurer 15 the establishment of electric currents inside the electric cathodic protection device 1 1.
• the detection of electric currents identifies an unstable condition of the potential in the tank 12.
• the stray currents may be small in entity, and therefore not produce a direct intervention of the electric safety devices, such as circuit breakers normally provided in the electric network.
• the detection step occurs for an interval of time T shorter than the overall functioning time of the heating apparatus 10 according to the invention.
• the time interval T lasts about one minute and is executed with a cyclicity of twelve hours, that is, the detection is performed periodically twice a day.
• Some forms of embodiment provide that, during the detection step, the supply of electric current to the current generator 14 is temporarily interrupted, and a measurement is made by the measurer 15.
• the measurer 15 detects the difference in potential, indicated hereafter as measured potential Vm.
• the measured potential Vm corresponds to the residual potential that is established between the electrode 13 and the tank 12. From experiment analysis, Applicant has found that, in the absence of electric dispersions, the measured potential Vm or residual potential quickly moves to an asymptotic value substantially stable over time, as shown in fig. 2b, similarly to the curve in which the measured potential Vml is detected.
• the controller 16 recognizes a functioning condition within the norm. To this end, in fig. 2b, the measured potential is indicated as Vml and it can be seen that Vml>Vr.
• the controller 16 recognizes the presence of harmful electric dispersions in the tank 12 and commands the activation of the indicators 17. In this condition, in fig. 2b the measured potential is indicated as Vm2 and it can be seen that Vm2 ⁇ Vr.
• One form of embodiment of the present invention provides that the period of time S is comprised between 30secs and 60secs.
• the period of time S before measuring, prevents the detection of transitory effects and allows to temporarily stabilize the functioning of the heating apparatus 10.
• Vm2 - 290mV.
• the controller 16 commands the current generator 14 to generate, between the electrode 13 and the tank 12, a difference in potential with a desired development and variable over time.
• the current generator 14 alternates in very short times, that is, about every 200 ⁇ 8, the generation of a first potential VI, and a second potential V2 with a reduced intensity compared to the first potential VI .
• the values of the first potential VI and the second potential V2 are determined so as to obtain a polarization of the electrolytic solution to a value corresponding to the protection potential Vp.
• the second potential V2 is comprised between 30% and 70% of the first potential VI.
• the variation in potential between the first potential VI and the second potential V2 can occur with a square wave development of period P which can be for example about 200 8 (fig. 3a).
• the controller 16 acts by modulating the current to be supplied to the current generator 14 so as to guarantee said protection potential Vp in the electrolytic solution.
• the measurements are taken by the measurer 15 when the potential at the heads of the current generator 14 assumes the value of said second potential V2.
• the measured current values Im are not subjected to big deviations, and remain confined in a band of values 18 that vary around a balanced current Ie as represented in fig. 3b.
• the processing unit 19 is able to identify the cyclicity of the values detected which, in the presence of stray alternating currents, vary with a frequency substantially equal to, or a multiple of, the latter, for example with a frequency of 50Hz or 60Hz or multiples thereof.
• the frequency at which the measurements are made must be greater than the frequency of the stray currents.
• the light indicators comprise a plurality of light sources, in this case (fig. 1) a red led 17a, a green led 17b and a yellow led 17c, each of which identifies a particular functioning condition of the heating apparatus 10.
• the controller 16 described above can also provide a function of counting the working time of the electric cathodic protection device 1 1.
• the yellow led 17c switches on and remains on until a maintenance operation is requested.
• the red led 17a can be used to indicate conditions of excessive electric absorption by the heating apparatus 10, or to indicate short circuit conditions or an open circuit in the heating apparatus 10.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Mechanical Engineering (AREA)
• Physics & Mathematics (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Materials Engineering (AREA)
• Thermal Sciences (AREA)
• Combustion & Propulsion (AREA)
• General Engineering & Computer Science (AREA)
• Prevention Of Electric Corrosion (AREA)
• Testing Resistance To Weather, Investigating Materials By Mechanical Methods (AREA)
• Coating By Spraying Or Casting (AREA)
• Control Of Heat Treatment Processes (AREA)
• Investigating Or Analyzing Materials Using Thermal Means (AREA)

Priority Applications (3)

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• 2013
  • 2013-03-08 IT IT000035A patent/ITUD20130035A1/it unknown
• 2014
  • 2014-03-07 EP EP14716929.6A patent/EP2964809B1/de active Active
  • 2014-03-07 ES ES14716929.6T patent/ES2622057T3/es active Active
  • 2014-03-07 WO PCT/IB2014/059534 patent/WO2014136097A1/en active Application Filing
  • 2014-03-07 PL PL16201549T patent/PL3170920T3/pl unknown
  • 2014-03-07 ES ES16201549T patent/ES2752849T3/es active Active
  • 2014-03-07 EP EP16201549.9A patent/EP3170920B1/de active Active
  • 2014-03-07 CN CN201710936904.9A patent/CN107686991B/zh active Active
  • 2014-03-07 PL PL14716929T patent/PL2964809T3/pl unknown
  • 2014-03-07 CN CN201480026014.9A patent/CN105189822B/zh active Active

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