US 1020480 A
Description (OCR text may contain errors)
I P. E. G. CUMBERLAND.- MEANS FOR PREVENTING CORROSION OF SURFACE cognnusms AND OTHER METAL STRUCTURES.
APPLICATION TILED APR. 27, 1911.
1,020,480. Patented Mar. 19, 1912.
4.; Atty I UN T D srrarrlsirlarnur OFF rnnnomun- ELLIOTT GLOUCESTER CUMBERLAND, or 's'n' KILDA, VICTORIA, AUS- TRALIA, nssxcnon r ALEXANDER MARKELL, or SYDNEY, AUSTRALIA.
MEANS'FORTREVENTING CORROSION OF SURFACE CONDENSERS AND OTHER METAL STBUCTURES.
Application filed April 27, 1911. Serial No. 623,609.
To all whom it may concern:
Be it known that I, PEREGRINE-ELLIOTT GLOUCESTER CUMBERLAND, a subject of the King of Great Britain, residing at St. Kilda,
- State of Victoria, Commonwealth of Australia, have invented certain new and useful Improvements in Means for Preventing Corrosion of Surface Condensers and other Metal Structures, fully described and represented in thefollowing specification and the accompanying drawings, forming a part of the same.
This invention relates to means for preventing corroslon of surfaces of metallic structures or bodies in contact with water or other liquids, and the invention relates more especially to means for preventing corrosion of parts of surface condensers in con tactv with the injection water. The tubes for the circulation of the injection water and some other parts of such condensers are usually made of brass, bronze or copper,,and
the partial or complete destruction of such parts as wellas of other parts made of other metals through corrosion, and especially electrochemical, or electrolytic, corrosion, has heretofore been-a serious obstacle to the successful and economical use of such condensers. This destructive corrosion is especially noticeable in the case of condensershaving sea water injection;
' Electrolytlc corrosion of metallic surfaces occurs whenever an electric current passes from a metallic surface directly to an elec-' trolyte. Such flow .of current may result from the production of local currents by stray currents which reach and tend to escape from ,a metallic body or structure.
Such electrolytic corrosion and also corrosion which results solely from chemical action may be prevented by maintaining between the metallic body or structure and an anode also in'contactwiththe electrolyte, a difference of potential such as to "produce an. elect-romotive force tending to cause a flow of current i to the metallic body or structure from the electrolyte greater than the electromotive force tendingto cause a flow of current from any part of the metallic body or structure to the electrolyte. Such counter electromotive force acts to prevent the flow of current froin particle of the surface of the metallic body or structure into the electrolyte, thus, preventing'electrolytic corrosion, and the our-.
rent flowing through the electrolyte from the anode tothe metal .to be protected causes hydrogen to be formed and to collect against.
the surfacevof the metal, which hydrogen any part or Specification of Letters Patent, Patented Mal. 19, 1912.
protects. the surface from chemical corrosion. This method of protecting -metal against corrosion has been proposed-heretofore and has been successfully employed by me, as described, for example, in my U. S. Letters Patent Nos. 921,641 and 948,968. It has also been proposdby others to pro- ,tect the parts of surface condensers in accordance with this method, but so far as am aware no practical means for supplying this method-to the protect-ion of surface con-v densers has been devised prior to my invention. I
The present invention aims especially to provide a practical, reliable and efficient apparatus or means for applying this method of protection to surface condensers, features of the invention, however, being capable of application for the protection of other,
structures, such as other forms of liquid containers; and the invention relates further to means whereby an indication will be given when an anode, through the corrosion which is diverted to it from the parts to be protected, becomes reduced to or near the point where it should be replaced with a n won a A full understanding of the invention can best be given by a detailed description of a preferred embodiment of the same as applied to a surface condenser, and such a de scription will now be given in connection with the accompanying drawings, showing such a preferred embodiment of the invention. v
In said drawings :-Figure 1 shows in longitudinal section a common form ofhorizontal surface condenser providedwith means embodying the present invention for preventing corrosion of the parts of the condenser in contactwith the injection 1 water. Fig. 2, is an enlarged sectional view .of one of the anodes and the supporting shell or casing with removable end plates or heads 11, and provided with a steam in' let 12 and an outlet 13 for the water of con- .densation. lVithin the casing are arranged the tubes 15 for the passageot the injection water supported at their ends by the usual tube plates 16 and opening. to chambers formed between the tube plates and the end plates 11, the space between the tube plate and the end plate at one end of the condenser being divided by the usual baflle plate 17 to form an inlet chamber 18 to which the injection water is supplied through a supplypipe 19 and a discharge chamber 20 from which the water is discharged through an overflow pipe 21. When the condenser is in operation the injection water supplied to the chamber 18 will flow through, the lower. tubes to the chamber 22 at the opposite end of the condenser and thence through the upper tubes to the discharge chamber 20 and out through the pipe 21.
Referring now to the means shown for carrying out the invention in connection:
with a condenser of the form shown, a plurality of blocks or bodies 30 of suitable ma terial to serve as positive electrodes or anodes are mounted withinthe condenser casing. Preferably one such body or anode will be mounted in each of the chambers 18 and 20 of the condenser shown and two such anodes in the opposite end chamber 22. These anodes should be set away from the walls or other parts of the condenser and thoroughly insulated therefrom, and they will be connected with the positive side or pole of a suitable source of electric energy supplying a direct current, the opposite side or negative pole or which is connected with the condenser structure. As shown, the source of electric energy is represented as a generator having its negative pole con nected by a wire a with the condenser casing and having its positive pole connected byline h with the several anodes 30 through branch lines. o. of which one leads to each anode. The source of energy mustbe of such character and capacity. as to maintain I adifierence of potential between the anodes 3 and theparts of the condenser in contact withtheinjection water suficient to cause a flowoiiLcurrent toall parts of the condenser fromfltli'e injectionwater under an electromotive "force which is greater than the electromotive-torce tending to'cause a flow of current trom'such part of the condenserto the injection. water, and to, supply an amount of current to each anode in excess of the aggregate amount of current which would in the absence of the protecting current flow from the part of the structure which each anode is to protect. In practice, a voltage very much in excess of that actually required may be used without any bad results, and a voltage considerably in excess of. that required is preferably employed. A considerable excess amperage is also not objectionable aside from the fact that the rapidity of destruction of the anodes is in proportion to the flow of the counter current; The amount or" current required is, however, comparatively small and a safe excess should be used because of the difiiculty or impossibility of determining the exact amount of current required except by noting the results obtained. Under ordinary conditions with even a comparatively large condenser of the form shown and with the anodes arranged as shown, I find that a current of one ampere supplied to each@ anode afiords full protection.
\ To. secure the proper supply of current to each of the several anodes, the anodes are connected in circuit through separate branch lines as before stated and-in each branch line there is provided a current limiting or determining means shown as a resistance 36 which is adjusted or adapted for supplying the desired amount of current through each anode. l/Vith the anodes arranged as shown, a substantially equal amount of current should be supplied to each anode. For providing such a resistance, 1 preferably employ filament lamps, both as a matter of convenience and because they serve also as visual indicators showing interruption of rent. In condensers as ordinarily constructed the various parts are soconnected as to provide good metallic contact between its various parts, and the single connection as shown with the source of current will ordinarily be suficient.
In the use of the apparatus, when the switch is closed to supply current to the anodes and the condenser shell is supplied with water, the anodes will be electrorpositive with relation to the parts of the condenser and the counter electromotive force under which the current tends to flow from the injection water or electrolyte to the parts of the condenser in contact therewith 'will preventthe flowor escape of current from any part or particle of such parts of wall to receive the nuts 42.
efficiency will also be overcome. The anodes Wlll be more or less rapidly corroded, and
when so far gone as to seriously impair their efficiency they will be replaced with new ones.
The anodes 30 may be of any suitable material and of any suitable form, but for economy and efficiency are best made of iron, and a convenient and suitable form is that of a flat circular body as shown. They may be supported and insulated in any suit-able manner providing for connection with the wires 0 and for the removal of used up anodes and attachment of new ones, but the supporting and insulating means shown is preferred and forms a feature of the invention. This supporting device comprises a metal bolt or bar 40 having one end screwed into a threaded socket 41 in the plate or body forming the anode. This bolt or bar passes through and is insulated from and secured in an opening in the plate forming the head 11 of the condenser. It is of sufiicient length to support the anode at a substantial distance from the condenser head or other wall to which it is attached.
with its outer end projecting outside the Aportion of the boltbetween the condenser headand the 1 anode carrier and is protectedby a sleeve 43 sleeve and the condenser head 11. The hole in the condenser head is made somewhat larger than the bolt. 40 to receive a ferrule 46 of fiber or other suitable insulating material which is best made of a length to extend inward past the washer 45 and into a socket formed in the endof the sleeve 43 and to extend outward through a washer 47 of fiber or other suitable insulating material which 1s placed betweentlier'condenser .head and the inner nut 42. A pro-tecting metal washer 48 is also preferably provided between the inner nut and the washer 47 and this washer 48 best hasan opening of sulficient size to receive the endof the ferrule 46. -When the parts arethus assembled with the bolt and ferrule, in the opening in the condenser head, the tightening of the inner nut 42 will draw the bolt outward, thereby causing the rubber washer 44 to be clamped tightly between the sleeve. 43 and the anode and the washer 45 to be clamped tightly between the sleeve and condenser head, thereb effectuall preventing access of Water to t e bolt. T e washer 47 will also be clamped tightly against" the condenser head and with the ferrule 46 will serve to insulate the bolt and nuts from the condenser head. By having the ferrule of sufiicient length to extend through the washers 45 and 47 and into the recessed end of the sleeve 43, possible danger of short circuiting through the medium of any water which might possibly gain entrance is practically eliminated. It will be seen that with the-anode supported in this way the supporting device is effectually insulated both from the condenser structure and from the water, and thatthere is no part of the sup port between which and any part of the condenser structure there is a path of less resistance for the current than-between the anode itself and parts of the condenser structure, and, also that the anode is supported without any part thereof in close proximity to any part of the condenser.
It is desirable that means be provided for giving some indication outside of the condenser when an anode has, through corrosion from the current passing from it to the electrolyte, been reduced in size to such a point that a new anode should be provided. To provide such means, the anode support, the
olt 40 in the construction shown, is pro: vided with a small passage or bore 50 extending from its inner end or a point which is normally closed by the anode to a point at its outer end outside the condenser casing. This passage will be sealed at its inner end so long as the anode covers the end of the bolt, but when corrosion of the anode has progressed to such an extent-that the end of the bolt is exposed the passage will thereby be opened and water will flow out from the condenser through the passage.
The escape of water from the. tell-tale passage 50 of any one of the anode supporting bolts will thus show that that particular anode has been corroded to such an extent that a new. anode should be placed in position. 41 in the anode or by otherwise changing the position of the inner end of the passage 50, which is normally sealedby the anode or' a part thereof, the indication may be caused to begiven for whatevercondition of the anode it is considered should call forv the renewalof the anode. It will be seen that one important feature of my invention comprises a source of elec' tricity, to the negative pole of which is con- By varying the depth of-the socket.
nected the .metalwork of the apparatus to he 1 I protected, while to the positive pole of said each other, these branch lines being arranged to carry current to the anode surface, the total amount of such anode surface necessary for the protection of the apparatus being sub-divided into port-ions distributed throughout the interior of the apparatus to be protected. These portions, each of which I will designate generally as an anode device, are insulated from the apparatus to be protected and located in the path'of the water, each anode device serving to protect that portion of the apparatus in its vicinity. Furthermore each anode device is connected to its own branch line only, whereby by providing suitable resistance in the branch lines each anode device may have the voltage impressed upon it controlled or determined independently of the voltage impressed upon any other anode device. lfn the particular embodiment of the invention shown in Fig. 1 of the drawings, each anode device consists of only one anode because in a structure of the size generally indicated in Fig. 1, a single anode at the termination of'its respective branch line can be made conveniently of such a size as to performits necessary function and yet not be too large to be readily supported so as to be mechanically strong and properly insulated from the apparatus without danger of injury to the insulation.
As hereinbefore explained in the specification, the anodes shouldbe set away from the walls or other parts of the condenser or other apparatus to be protected and in the example shown the anodes 30 are supported substantially inthe middle of the respective chambers. This is for the pose .of obtaining a substantially uni orm distribution of the current from the anode to the various adjacent parts of the apparatus to" be protected. If the anode is placed in substantially close contact with either wall so much of the current would 45 return through such wall that it wouldbe difficult to drive enough current to other parts of the apparatus to protect the same.
It will be understood that the invention may be employed in connection with surface condensers of various forms, whether for marine or land use, and that features of the invention, as claimed, may be applied to or used for the protection of, other structures. v 55 It will be understood also that the invention is not to be limited to the exact con: struction and arrangement of parts as shown, but that itincludes changes and modifications thereof within the claims.
What I claim is:
1. In a system for preventing corrosion, the-combination,,with the apparatus to be protected, of a source of electricity, means for connecting the said apparatus to the negative pole of said source of electricity, a
I nected to one branch line only, and means for controlling and determining thevoltage impressed on each anode device independently of the voltage on any other anode device. 1 i
2, The combinatlon with a surface condenser, of means for preventing corrosion of 7 parts thereof in contact with the injection water comprising a plurality of anodes mounted within the condenser casing and insulated therefrom, a sourcaofelectrical energy, means electrically connecting the parts of the condenser to be protected with the negative side of the source of electrical energy, a separate branch line connection leading from each anode to the positive side of the source of electrical energy, and a resistance in each of said branch linesfor controlling and determining the amountof current supplied through each anodes 3. The combination with a surface condenser having water chambers at the ends of the tubes including an inlet chamber and a discharge chamber, of means for preventing corrosion of parts of the condenser in contact with the injection water comprising a plurality of anodes 'inounted one or more in each of the water chambers and insulated from the condenser, a source of electrical energy, means electrically connecting the parts of the condenser, to be protected with the negative side of the source of electrical energy, a separate branch line connection leading from each anode to the positive side of the source of electrical energy, and a resistance in each of said branch lines for controlling and determining the amount of current supplied through each anode.
4. The combination with a surface condenser, of means for preventing corrosion of parts thereof in contact with the injection water comprising an anode mounted within the condenser casing, asupport for the anode formed of a metal bar extending through an opening in and secured to the condenser casing, means for insulating said metal bar from the shell and from the water, a source of electrical energy, and means electrically connecting the parts of the condenser to be protected-with the negative side of' the source of electrical energy and the anode'support with the positive side of the source of electrical energy.
5. The combination with. a surface condenser,- of means for preventing corrosion of parts thereof in contact with the injection water, comprising a plurality of anodes mounted within the condenser casing and Insulated therefrom, a source of electrical tenergy, means electrically connecting the parts of the condenser to be protected'with the negative side of the source of electrical energy, connections from the anodes to the positive side of the source of electrical energy, and indicating meansfor each anode arranged to indicate the time for renewal of said anode.
6. The combination with a metallic body or structure, of means for preventing corrosion of parts thereof in contact with liquid comprising a plurality of anode devices mounted in position to be in contact with the liquid with which t-he parts of the structure to be protected are in contact, said anode devices being insulated fromsaid body or structure, a source of electrical energy,
- means electrically connecting the parts of the body or structure to be protected with the negative side of the source of electrical energy, a separate branch line connection from each of said anode devices to the positive side of the source of electrical energy, and a resistance in'each of said branch lines for controlling and determining the amount of current supplied through each anode.
7. The combination with ametallic body or structure, of means for preventing corrosion of parts thereof in contact with a liquid comprising a plurality of anode de: vices mounted in position to be in contact with the liquid with which the parts of the structure to be protected are in contact, said anode devices being insulated from said body or structure, a source of electrical energy, means electrically connecting the partsof the body or structure to be protectedwith the negative side of the source of electrical energy, a branch line connection from .each of said anode devices to Jt-he positive side of the source of electrical energy, and a filament lamp in each of said branch lines to control and determine the amount of current supplied through each anode device and to serve as an indicator to show the condition of each branch circuit.
8. The combination with a liquid contaming structure, of means for preventing corrosion of parts of the structure in contact ,with the liquid, comprising an anode mounted withinthe structure in position to be in contact with the liquid in the structure and insulated from the structure, a source of electrical energy, means electrically connecting the parts of the structure to be protected with the negative side of the source of electrical energy and the anode with the positive side of the source of electrical en-.
ergy, and a tell-tale passage extending from a point within the anode to a oint outside the structure whereby when t e anode has been reduced by corrosion sufliciently to ex-' pose the end of the tell-tale passage water will pass out through the passage.
9. The combination with a liquid containmg structure, of means for preventing cor- ,and compress the washers.
rosion of parts of structure in contact with the 11 1nd, comprising an anode mounted within the structure 1n position to be in contact .with the liquid, a support for;
the anode-formed of ametal bar extending through an openingin andsecured'to an outer wall of the structure ata point below the water level, means for insulating said supporting bar from the Wall'of the structure and from the liquid, a tell-tale passage extending through the supporting bar from a point within the anode ,to a point outside the structure, a source of electrical energy, and means electrically connecting the parts of the structure to be protected with the negative side of the source of electrical energy andthe anode support with the positive side,
of the source of electrical energy.
adapted toserve as a positive electrode, of an insulating support therefor having a tell-tale passage extending'from the outer end of the supprn'tto a point within the anode. 4 p
11. The combination, with an electrode.
of a bar of conducting material secured to the electrode, a sleeve and a ferrule of in sulating material mounted onsaid bar, a washer between the sleeve and the electrode, a pair of washers surroundingthe' ferrule, and means for drawing the bar in a direction to pull the electrode toward the sleeve 10. The combination with a metal body .I
12. The combination with the metal body to be used as a positive electrode, of a supporting bar, to one end of which the electrode is secured, an insulating sleeve on the bar, washers at the ends of the sleeve, an insulating ferrule to pass through an opening in a wall or plate to which the supporting bar is secured, said ferrule extending through the washer and into a recess in the end of the sleeve, an insulating washer to engage the outer side of the plate or wall to which the bar is secured, and means for drawing the bar outward against the resistance of the sleeve whereby the insulating washers will be compressed and the bar will be securely positioned.
13. The combination, with the metal body to be used as a positive electrode, of a supporting bar, to one end of which the electrode is secured, an insulating sleeve on the bar, an insulating ferrule to pass through .an opening in a wall or plate to which the protected, of a plurality of anode devices located Within said apparatus and insulated therefrom, means for establishing an electro-motive force at each anode device independent of the electro-motive force at any other anode device, and-means for connecting said apparatus as a cathode for each device independently of the amount supplied throughany other anode device,
16. The combination With a liquid containing structure, of means for preventing corrosion of parts of the structure in contact With the liquid, comprising an anode and means for supplying current to the anode and for connecting the structure to act as a cathode, said anode being located Within the structure'in position to be in contact with the liquid in the structure and carried by an insulating support extending from a part of the structure below the surface level of the liquid and supporting the anode at a substantial distance from said part ofthe structure and formed to present a surface of insulating material to the liquid between the anode and the structure, whereby current to pass through the liquid to the structure will be delivered only at a point remote from all portions of the structure to be protected.
17. The combination, with an electrode, of a supporting bar ofconducting material to one end of which the electrode is secured, means for securing the supporting bar in an opening in a Wall or plate with the electrode at a substantial distance from the Wall or plate, and means for insulating the supporting bar comprisin a sleeve of insulating material forming an outer covering of the supporting bar,
18. vThe combination, with an electrode,
of a supporting bar of conducting material to one end of which the electrode is secured, means for securing the bar in an opening in a wall or plate with the electrode at a substantial distance from the Wall or plate, and insulating means comprising a sleeve of insulating material forming an outer covering of the supporting bar between the electrode and the Wall or plate.
" In testimony whereof, I have hereunto set my hand, in the presence of two subscrih 111g wltnesses. I
PEREGRINE ELLIOTT etouonsrne CUMBERLAND.
' Witnesses: o
.. A. L. KENT,
J EA'NNETTE Sworn,