US2381183A

US2381183A - Apparatus for and method of rustproofing

Info

Publication number: US2381183A
Application number: US440853A
Authority: US
Inventors: Ernest W Richards
Original assignee: Parker Rust Proof Co
Current assignee: Parker Rust Proof Co
Priority date: 1942-04-28
Filing date: 1942-04-28
Publication date: 1945-08-07
Anticipated expiration: 1962-08-07

Description

Aug. 7, 1945. E. w. RICHARDS APPARATUS FOR AND METHOD OF RUSTPROOFING Filed April` 28, 1942 5 Sheets-Sheet l Y INVENTOR Z4/'276521 WZ'C/a r's,

BYW A) ATTOR N Aug. '7, 1945 E. w. RICHARDS APPARATUS FOR AND METHOD OF RUSTP'ROOF'ING 1942 5 Sheets-Sheet 2 F11-ed A pril 28 INVENTORP 247776.52? Macdr-.

ATTORNE Aug. 7, 1,945. E. w. RICHARDS 2,381,183

APPARATUS FOR AND METHOD OF RUSTPROOFING Filed April 28, 194.2 5 Sheets-.Sht-BBl 3 Ti .L a l Y "5.40 il:

ATToR'NEY Aug. 7,'1945. E. w. RICHARDS APPARATUS FOR AND METHOD OF RUSTPROOFING Filed April 28, 1942 5 Sheets-Sheet 4 ATTORN EY.;

5 Sheets-Sheet 5 INVENTOR l Il l l .l l llllll ATTORN Aug. 7, 1945. E. w. RICHARDS l APPARATUS FOR AND METHOD OF RSTPROOFING Filed April 28, 1942 www afa ' and/orl removing sludge or other foreign material d which has collected on the rolls without contaminating the first mentioned solution, discontinuing Patented Aug. 7, 1945 APPARATUS FOR AND METHOD 0F RUSTPROOFING Ernest W. Richards, St. signor to Parker Rust Mich.

Clair Shores, Mich., as- Proof Company, Detroit.

Application April 28, 1942,- Serlal No. 440,853

15 Claims.

This invention relates to a method of chemically coating metal strips or sheets and to apparatus for carrying out such method, the principal object being the provision of a method and apparatus for the above stated purposes by the prac-. tice and use of which chemical coating of such metal plates or sheetsvmay be accomplished in a quicker and more eillcient manner.

Objectsv of the invention include the provision of a method of chemically coating metal sheets or strips comprising providing a liquid circulating system and introducing said sheets or strips into such' system' for contact with' the liquid therein, and providing a second liquid circulating system including that portion of the rst systemy in which the sheets or strips are contacted by the said liquid therein, and alternately operating each of said systems while rendering that portion of the other system which is common to both sys` tems inoperative and sealed from the liquid of the operating system without otherwise disturbing the normal arrangement of either of said systems; the provision of a methodes above described inluding the steps of rendering that portion of said system common toboth inoperative as to both, and causing liquid from a third source to be circulated through/'said cormxnonl portion without comingling `with the liquids of either one of the other two systems. l

Other objects oi' the invention vinclude the'provision of a method of chemically coating sheets or strips of metal bypassing them through pairs of cooperating rolls and subjecting them to the efe fects of la chemical solution in'a liquid rel-circulating system during their passage between such 3 pairs of rolls, intermittently discontinuing the circulation of said solution and circulating in its stead through a -portion of the iirstmentioned systeni'ra second solution capable of loosening the now or the second mentioned solutionv and then resuming the circulation ci' the rst mentioned solution without contamination of the second mentioned solution thereby; the provision of a method of chemically coating sheet or strip metal as above described in which rinse water is applied to the 4rolls through a portion of the liquid re-circulating system between the time the secondsolution is 'applied thereto and the time the tlrst solution is reapplied thereto; the provision of a method of chemically coatmg the sheet or strip metal as above described in which the rst mentioned solution is applied to the sheets or 5 strips through a plurality of spray nozzles; the provision of a method of chemically coating sheet or strip metal as above described in which the second mentioned solution is applied to the sheets or strips through the same nozzles that the iirst mentioned solution is applied thereto; the provision of a method of chemically coating sheet or strip metal as above described in which the second mentioned solution is recirculated through such 'nozzles without contaminating the firstmentioned solution; and the provision of a method of chemically coating sheet or strip metal as above described in which the rinse water is applied to the rolls through the same nozzles as the rst and second mentioned solutions are applied to the roll and in'such a manner as not to contaminate either the ilrst or the second mentioned solutions.

Further objects of kthe invention include the 2o provision of means for chemically coating sheet or metal strips comprising a plurality of cooperating pairs of rolls through which such sheets are adapted to be'passed, means for circulating a chemicalsolution into contact vwith the sheets 25 or strips during theirpassage between adjacent pairs of rolls, means for collecting and draining said solutions for recirculation into contact with said sheets o'r strips, means for discontinuing the circulation of said solution and circulating 1n its stead through a portion of said system a second solution for the purpose cf cleanlng'said rolls, and means for draining and collecting said second mentioned solution separately from the first mentioned solution; the provision of apparatus as above described involving novel means whereby the two solutions may be separately collected without contaminating one another; the provision of apparatus as above described including means for circulating a rinse water in contact with the rolls after they have been subjected to the cleaning solution and without contaminating eitheroi the first two mentioned solutions thereby; the provision of apparatus as above described in which the means for circulating the ilrst mentioned so- 5 lution includes a plurality of spray nozzles through which` the first mentioned solution is delivered to the sheets or the strips passing between adjacent pairs of rolls; the provision of apparatus as above described in which means are provided Afor effectingV a circulation of the second mentioned solution through the same spray nozzles as the rst mentioned solution is lapplied to the sheets or strips; the provision oi apparatus as above described in which the rinse water is applied to the 5 sheets or strips through the same nozzles as the nrst and the second mentioned solutions are applied thereto together with means for preventing contamination of the first and second mentioned solutions by the rinse water; the provision oi' a novel form of solution collecting tanks for use with apparatus of the type described; and the provision of a novel form of sludge settling tank for use in connection with apparatus of the type described.

The above being 'among the objects of the present invention the same consists in certain novel steps or combinations of steps of operation, novel features of construction and combinations of parts to be hereinafter described with reference to the accompanying drawings, and then claimed, having the above and other objects ink view.

In the accompanying drawings which illustrate suitable embodiments of apparatus by means of which the method of the present invention may be carried out, and in themselves constituting suitable embodiments of apparatus forming part of the present invention, and in which like numerals refer to like parts throughout the several diiferent views, l

Fig. 1 is a more or less diagrammatic side elevational view of apparatus embodying the present invention and capable lof being operated to carry out the method thereof;

Fig. 2 is an enlarged, partially broken plan view of the central portion of the apparatus illustrated in Fig. 1;

Fig. 3 is a still further enlarged, vertical sectional view taken on the line 3 3 of Fig. 2;

Fig. 3a is a more or less diagrammatic, en-

arged and fragmentary plan view illustrating i. portion of the rolls shown in Fig. 3 and the' neans for driving the same;

Fig. 4 is a transverse sectional view taken on ;he'llne 4-4 of Fig. 3;v

Fig. 5 is a transverse sectional view taken on the line 5-5 of Fig. 3;

Fig. 6 is a view equivalent to that of Fig. 3 but ;aken through a modified form of construction;

Fig. 'l is a fragmentary plan view ofthe apparatus shown in Fig. 6; and,

Fig. 8 is an enlarged transverse sectional view taken on the line 8 8 of Fig. 6;

'I'he present invention relates to the production of coatings on metal surfaces by the action thereon of chemical solutions. Typical of such coatings are phosphate coatings applied to iron, steel, zinc or the like to form a bond for paint. While the present invention may be useful in connection with the application of other chemical coating solutions, it will be described in connection with the production of phosphate coatings to obtain paint bonding coatings for which purpo it is especially suited.

Thepnesent invention is particularly adaptable for, but not necessarily limited to, use in connection with apparatus for producing such chemical coatings on metal surfaces disclosed and claimed in the application. for Letters Patent of the United States for improvements in Apparatusfor' rustproonng sheet metal, nled by Robert R. Tanner on August 21, 1941, and serially numbered 407,775, and for that reason such type through the rolls are sprayed on both surfaces thereof with a chemical solution which interacts with the metal of the sheets or strips to provide the desired chemical coating for the surfaces thereof. Experience has taught that in the chemical coating of metal sheets or strips by the Tanner apparatus above described the interaction between the chemical solution and the metal of the sheets or strips produces a sediment or precipitate or sludge which has a tendency to adhere to the surfaces of the rolls, and that when the rolls, and particularly those at the entrance end of the apparatus, become suiiiciently coated with such sludge. it has an adverse effect on the desired rapidity and character of the chemical action of the solution on the sheets or strips. It has. therefore, been found necessary to discontinue operation of the apparatus at intervals and clean such sludge or other foreign material from the surface of the rolls, or at least' those rolls at the entrance end of the apparatus.

In employing the apparatus disclosed in said Tanner application the chemical solutions with which the metal plates or strips are treated is pumped .under pressure through spray nozzles and directed against the opposite faces of the sheets or strips, the rolls continuously and repeatedly remove such solution from the surfaces of th`e sheets or strips and discharge it therefrom, and such solution is suitably drained into a suitable tank or reservoir from which it is recirculated by a pump through the above described nozzles. In

order to clean the foreign material from the rolls,

which is best done by a cleaning acid solution applied to the rolls through the same spray nozzles as are employed to apply the chemical solutions to the sheets or strips, the past practice has been to pump the chemical solution out of the apparatus and into a temporary holding tank. The

cleaning acid solution is substituted in the ap-I paratus in place of the chemical solution, and is circulated until the rolls are clean; the acid solution is then drained oi! into a separate tank, a

water rinse is passed through the system to clean of which the operation of the machine for its intended purpose is interrupted. It is, thereforethe principal object of the presentvv invention to' provide a means and method by the use of which these undesirable interruptions in the operation of the type of apparatus referred to may be considerably shortened and simplliled, thereby permitting the apparatus to be operated at a greater wherebyeither one or the other of such systems of apparatus ia employed by way of illustration the metal sheets or strips to be coated are passed and which sheets or strips during their passage may be rendered operative while the other system is rendered inoperative and sealed over that length thereof common to both systems against contamination by liquid in the qperative system. By this method, and apparatus for carrying it out, it is not necessary to temporarily remove the liquid from either system but it may be retained4 therein while the other system is operating and consequently the time heretofore lost in draining one system and then the other and refilling the systems is eliminated. The improvements of the present invention further contemplate the rendering of the common portion of both -systems inoperative as to both systems but open to the flow of rinse water therethrough, whereby the portion of the apparatus in which the work is treated may be rinsed free of both solutions and particularly the cleaning solution.

Referring now to the drawings which illustrate preferred embodiments of the apparatus and particularly to Figs. 1 to 5, inclusive, which illustrate one form thereof, it will be seen from inspection of Fig. 1 that the metal sheets or strips to be treated are first passed through a surface preparing step indicated generally at l2 and then pased over a series of rolls l 4 to the principal part of the apparatus and which includes a section A in which the sheets or strips are subjected to the effects of a chemical solution in order to provide the same with a chemical coating, next a section B in which the sheets or strips are washed with water to clear them of such chemical solution, and a section C within which the sheets or strips thus washed in the section B may be treated to a bath consisting of an acid solution and particularly to troughs 24. These end flanges also serve as bafes to prevent direct passage of liquid from the end portions tothe central portion 22. 'I'his shield 26 extends between the opposite side walls I8 so that it acts in conjunction with the bottom end wall portions 2li to cause all the liquid that is discharged into the section A above the bottom walls 20 and shield or drainboard 2B to be delivered to the troughs 24 before it can find its way to the central bottom section 22 by overflowing the inner walls of the troughs.

Above the bottom end wall portions 20 and shield 2B are a plurality of pairs of rolls 30.

. These rolls are arranged with their axes horia chromic acid solution where the chemical solution employed in section A is of a phosphate character. 'I'he sheets or strips as they are delivered from the section C are in a condition when dried for fabrication and subsequent painting.

The section A is the one which the present invention is primarily concerned with and as il1ustrated this includes a, spray tank portion consisting of a pair of vertically laterally spaced side wall portions I6, a pair of transverse vertically directedA end walls I8, one of which is brought out in Fig. 3, and bottom walls. The bottom walls comprise two end portions 20 which, as best brought out in Fig. 1, extend from the corresponding end of the section downwardly towards the center thereof but, as'best brought outin Fig. 3, these stop short of the forward 'and rearward edges of the central bottom section 22-whichis of V-shape in crosssectional conformation as viewed in 'side-.elevaftion. The forward and rearward edges-bof 'the'v central bottom section 22 are eachl joined totliev corresponding bottom end section. 2li through a transversely extending trough 24 whicntrou'gha.

as best shown in Figs. 2 and 5.v project outwardly j: beyond one of the side walls '16. As bess' brought out in Fig. 3, the line of junction-.of thecentral portion .22 with the adjacent wall of the trough 24 is located vertically belowthe line of junction of each bottom portion 20 with its corresponding wall of the trough 24, the purpose of this arrangement being to insure that any liquid which is re* ceived by the bottom end sections 20 will be drained thereby into the troughs 24 and fill the troughs 24 to the height of the inner walls there-l of, as viewed in Fig. 3, before such liquid overflows into the central bottom section 22.

In order' to insure that liquid discharged between the side walls I6 and over the length of the central bottom section 22 will likewise be zontal and transverse to the path of movement of the strips or sheets I0 passing through the apparatus. One roll of each pair is superposed over the other and suitable means (not shown) are provided to press the rolls of each pair into contact with each other. In Fig. 3 only a, relatively few pair of such rolls are indicated, this being for the purpose of simplicity in drawing whereas it will be appreciated that such pairs of rolls 30 are arranged in relatively closely adjacent relationship with respect to each other and preferably throughout the entire length of the section A. Ifdesired an idler roll such as 32 may be mounted between each pair of rolls I0 and in line with the lower roll of such pairs so as to provide an added support for the sheets or strips passing between adjacent pairs of rolls. All of such pairs of rolls are preferably so mounted between the side wall I6 that the line of contact between the rolls of each pair of rolls lies in the same horizontal plane as the corresponding line of contact between the rolls of all the remaining pairs of rolls. Furthermore, each roll 30 is preferably of a yieldable or resilient chara'cter, which characteristic is preferably imparted thereto by providing it with an external layer of rubber or the like, or forming it entirely of such material except for the shaft upon which it is supported.

At least one roll of each pair of rolls 30 is driven so as to mechanically advance the sheets or strips I0 therethrough when introduced between each pair of rolls in succession. Any suitable means may be provided for driving one roll of each pair of rolls such, for instance, as an electric motor (not shown) acting through the speed reduction`mechanism 34 (see Fig. 3a) and chain 33 arranged to engage a sprocket carried by the shaft of one of the rolls 30 which it is desired to drive. The shafts of one roll of each pair of rolls 30 may be provided with a pair of sprockets thereon, so that an endless chain such as I8 may be employed to drivingly connect each adjacent pair of such rolls. Any other suitable means of driving the rolls may, of course, be employed and,

for instance, it may be the same as or equivalent to the arrangement shown in the copending application of Robert R. Tanner previously identitied herein.

The solution is applied to the'sheets or strips Illin their passage through the rolls It by means of a, multiplicity Aof nozzles 60 best brought out in Figs. 3 and 4. `As indicated in these figures, and particularly in Fig. 4, a plurality of such nozzles 50 are carried by each of a plurality of pipes 52 which are arranged horizontally and extend transversely of the direction of movement of the sheets or strips I0 through the apparatus for substantially the fulllength of the apparatus. At least one of such pipes 52 is arranged above the plane of passage of the sheets or strips I0 and one below such plane between each adjacent pair of rolls 30 and preferably, as illustrated in Fig. 3, two such pipes are so located. The pipes 52 below the plane of passage of the sheet or strips I0, where the idler rollers 32 are employed, are preferably so located that one is positioned horizontally between each idler roll 32 and the rolls 30 on each side thereof as illustrated. The nozzles 50 carried by the pipes 52 are arranged to direct the spray of liquid therefrom not only on the corresponding surfaces of the sheets or strips i passing through the adjacent rollers 30 but also to bathe the surfaces of such rolls. It may be noted, particularly from an inspection of Fig. 3, that the pipes 52 and nozzles 50 are eliminated in connection with the last few pairs of rolls in section A, and these rolls are shielded fromthose in advance thereof by baffles 53. These baiiled rollers are for thev purpose of removing substantially all of the chemical solution from the work before it passes into section B. It will also be noted in Figs. 4 and 5 that the spray tank of section A is provided with a cover to retain the spray from the nozzles 50 therein.

As best brought out in Figs. 3 and 4 the pipes 52 extend out through one of the side walls I6 and are there connected to sub-headers, the upper pipes 52 being connected to different subheaders than the lower pipes 52. The sub-headers for the upper pipes are indicated at 54 and those for the lower pipes at 56. The sub-headers 54 and 56 are of limited length as, for instance,

i sufficient to take care of ten pipes 52, in the man-r ner illustrated in Fig. 3, and such sub-headers 54 and 56 are in turn connected to a main header 58 through valves such as 60, the main. header 58 extending the full length of the section A. As best brought out in Fig. 3 the main header 56 at the righthand end thereof is joined through a shut-off valve vlil to a. vertically extending pipe 62 which extends downwardly therefrom and connects into the discharge side of a liquid circulating pump 64, best shown in Fig. 2 as forming a part of a unit including an electric driving motor 66 drivingly connected thereto.

The pump 64 thus delivers the chemical solution therefrom through the pipe 62 tothe header 58 from which it flows through the various subheaders 54 and 56 to the various pipes 52 and through the nozzles 50 thereof into contact with the sheets or strips passing through the rolls 30, as well as the

rolls

30 and 32, themselves, and from which it is dischargedonto the bottom sections 20 and shield 26 and then drained into the troughs 24 from which-it overflows into the central section 22. As brought out in Figs. 2 to 5, inclusive, the central bottom section 22 forms a tank or reservoir which is provided With a lateral extension 10, The tank extension 10 is provided with vertical side walls but its bottom is of V section and consists primarily of an extensic-n of the bottom portion 22. Outwardly beyond the corresponding side I6 and as perhaps best brought out in Fig. 2, the tank-like extension 10 is joined in substantially open communication with a longitudinally extending tank or tank section 12. That portion of the bottom section 22 below the sides of the lateral tank extension 10, and the corresponding portion of the tank extension 10, serves as a settling chamber in which the sludge formed by the inter-action of the chemical solution with the metal being processed may collect so that the bulkr of it will not be carried into the tank extension. 12. It will thus be appreciated that the solution which is drained into the troughs 24 and overflows into the central bottom section 22 thus flows into the extensions 10 and 12. The righthand end wall of the latter, as viewed in Fig. 2, is connected by a pipe 14 to the inlet side of the liquid circulating pump 64, a. valve 16 being provided in such pipe 14 for the purpose of closing it tothe flow of liquid therethrough when desired. VFrom the above it will be appreciated that the mechanism thus far described provides for the continuous circulation of the chemical solution through the nozzles onto the sheets or strips being processed, then draining the same into the central bottom section 22 from which it iiows into the tank extensions 10 and 12 and is redelivered to the intake side of the pump 64 for redelivery to the nozzles 50.

In order to aid in removing the sludge in the solution which is neither trapped in the troughs 24 or in the bottom of section 22 Vand tank extension 10, the following mechanism is provided. A vertically extending baiile is extended approximately half way across the open end of the tank 12, asbest brought out in Fig. 2 and between the baille 80 and the opposed side wall of the tank extension 1D pairs of vertically extending filters 82 are placed in intercepting relation with respect to the oW of liquid through the tank extension 10. The filters 82 rest on supports 84 also extending between the baille 80 and the opposite side wall of the tank extension 10 and, as best brought out in Fig. 4, imperforate shields 86 extend downwardly therefrom to a point adjacent to but spaced from the V-bottom portion of the tank extension 10. This is for the purpose of directing the sludge separated out by the filtersl 82 into the bottom of the V of the bottom portion 22 and tank extension 10 where it may collect without too much danger of being again picked Yup by the solution and be recirculated therewith.

For the purpose of removing such sludge from the bottom of the bottom section and tank extension 10 a perforated pipe 88 is positioned in the V-bottom of the same and projects out from either end thereof as best brought out in Fig. 4. As best brought out inFig. 2 the opposite ends of the perforated pipe 88 are connected by two lines of piping 90 and 92, respectively, which are joined together and then connected to the intake side of a pump 94 driven by an electric motor 96. A valve 98` is included in the

pipe lines

90 and 92. By opening the valves 98 and operating the pump 94 it will be appreciated that the sludge may be drawn through the perforated pipe 88 and discharged by the pump 92.

In order to further remove the sludge from the chemical solution with which the sheets or strips passing through the apparatus are treated, additional pairs of filters |00 are interposed across opposite walls of the tank 12 adjacent each end thereof as best brought out in Fig. 2. As best brought out in Figs. 2 and 5 steam coils 402 are positioned in the tank 12 between the filters 100 for the purpose offheating the chemical solution being circulated to a temperature best suited for the operation, and they may be fed with steam from any suitable source.

When it is desired to clean the rolls 30, then it is necessary to drain the troughs 24 of the chemical solution therein before the cleaning operation begins so as to prevent any contamination of the chemical solution in the troughs 24 with the cleaning liquid. Such clearing of the troughs 24 is accomplished in the following manner. As best illustrated in Fig. 4 it will be noted that the bottoms of the troughs 24 are inclined down- Y wardly and to the left as viewed in that figure and project outwardly beyond the corresponding the lower portion of the lefthandr trough 24, as viewed in Figs. 1, 2 and 3, and a pipe I2 into the righthand one thereof, and each of the pipes H and ||2 is provided with a valve ||4 therein. Thesepipes |I0, v| |2-,-as-best brought out in Fig. 2, are connected into a header ||6 provided with valves ||8 and |20 on either side of the point of connection of the pipes 1||0 and ||'2 therewith. Between the valves ||8 and |20 a pipe |22 provided with a valve |24 therein connects the header ||6vwith the small tank |26 so that by closing the valve ||8 and |20 and opening the valves ||4 and |24- the solution in the troughs 24 may be drained into the tank |26. The bottom of the tank |26, as best brought out in Figs. 2 and 5, is connected by apipe |28 having a valve |30 therein with the pipe 80 which. connects the perforated tube 88 with bthe pump 94. Thusby closing the valves 98 and opening the valve |30, upon operation of the pump 94 the contents of the tank |26 will be discharged from the pump 94.

Thus the pump 94 not only serves to withdraw` sludge accumulation in thebottom of the tank the top and bottom thereof. A rubber hose |60 is connected to the pipe |58 within the tank |42 and a float |62 is connected to the free end of the hose |60 by straps such as |64, so that the extension 10 through the perforated tubes 88 but.'

also solution from the tank |26, and by suitablyzfz operating the valves 98 and |30 this may be ac-i complished separately or simultaneously. It will be appreciated that the solution in the tank |26 which is drained from the troughs 24will usuallyY Vcarry a relatively high amount of sludge thereout in Fig. 4, and which is suitably supported inA elevated relation with respect to the remaining v portion of the apparatus as indicated. As indicated in Fig. 4 the pipepline |40 discharges into the upper end of the sludge tank |42 which is preferably closed by a cover |44. VThe sludge tank |42 is provided with a conical'bottorn section |46, the lower end of which is connected to a discharge pipe |48 controlled by the valve |50. 'Ihe pipe |48 may extend to a sewer or other suitable point of discharge. An overflow pipe |56 is connected into the upper portion of the sludge tank |42 and leads to the upper portion of the tank extension 'l0 so that in event there should be more sludge and solution discharged into the sludge tank .|42 than it is capable of carrying, the excess will simply ow therefrom back into the solution reservoir portion of the apparatus.

The sludge carrying solution which is discharged into the sludge tank |42 is allowed to remain therein without disturbance for a suitable length of time during which the sludge itself will settle out of the solution and into the bottom of the tank |42. When this settling has occurred then the clear solution above the sludge may be withdrawn from the tank |42 and discharged back into the tank 10. This is accomplished as illustrated in Fig. 4 by extending a pipe |58 from the upper portion of the tank 10 to a point within the sludge tank |42 and approximately midway free end of the hose |60 will always remain below the level of the solution in the sludge tank |42. The pipe |58 is equipped with a valve |66 therein so that when the sludge has had an opportunity to settle out of the solution delivered to the sludge tank I 42, the valve |66 may be opened whereupon the clear liquid adjacent theupper surface of the solution in the tank |42 may drain by gravity into the-tank 10. A workman watching the discharge of such solution through the pipe |58 into the tank 10 will observe when the free end of the hose |60 drops low enough in the tank |42 so that it begins to pick up the sludge in the bottom portion thereof, whereupon he may close the valve |66 and then open the valve |50 to discharge the sludge thus collected in the tank to the sewer. In orderto clean this sludge thoroughly from the bottom of the tank |42 a water pipe |68 is extended into the tank |42 so as to discharge water into the conical bottom portion thereof, and the flow of such water may be controlled by a suitable valve such as |10.

The apparatus thus far described thus provides for passing metal sheets or strips through a multiplicity of.cooperative pairs of rolls, spraying a chemical solution upon the sheets or strips during their passage through the rolls, draining the solution from the sheets or strips into the troughs V24 fromV which it may overflow into a tank or reservoir and in which the sludge is separated out therefrom, and then redelivering the solution to the spray nozzles for again bathing the sheets or strips being treated. Means are also provided for withdrawing the sludge concentrations from the tank or reservoir and for draining the chemical solution and any sludge associated therewith from the troughs 24 and delivering them to the sludge tank |42 in which the sludge and solution may be separated from one another, and then redelivering the separated solution to the tank or receptacle and discharging the sludgeto a sewer or the like.

'Iwhe acid or other solution with which the rolls 30 are to be cleaned is contained within a tank shown at the righthand end in Figs. 1, 2 and 3. As indicated in Fig. 3 steam coils |82 may be located in the tank |80 in order to heat the acid or other solution therein in order to render it more eflicient in operation. Thetank |80 is provided with an outlet pipe |84, best brought outl in Fig. 2, having a shut-off valve |86 therein, and

which extends to the inlet side of a pump |88 driven by an electricmotor |90, best brought out in Fig. 3. The discharge side of the pump |88 is connected by a pipe |92 to a header |94 arranged above the header 58v and connected thereinto as best brought out in Fig. 3. The header |94 is provided with a pair of `shutof valves |96 therein. It will thus be appreciated that by shutting olf the valve 16 to the inlet side of the pump 64 and the header valve 6| and by then opening the valves |96 and operating the pump |88 the acid or other solution' in the tank |80 may be withdrawn from the tank |80 and discharged into the header 58. fro'm which it will eventually be discharged through the various nozzles 50 against the

various rollers

30 and 32. During this operation it will, of course, be appreciated that no work will be passed through the rollers 30 and that, for instance, where strip metal is the type of work being operated upon, it may be replaced by a leader strip for the cleaning operation. At times it will be suflicient to clean only part of the rolls in which case valves 80 may be closed except the one or more that leads to the rolls which are to be cleaned. v

The cleaning solution which is thus discharged through the nozzle 50 upon the

various rolls

30 and 32 will be discharged therefrom and will flow into the troughs 24 in the same manner as the chemical solution previously described. lIn this case, however, because of the fact that the bottom portion 22 and the tanks 10 and 12 are filled with the chemical solution at this time it is, of course, essential that the cleaning solution which is discharged into the troughs 24 be prevented from overflowing the edges thereof and into the bottom portion 22 where it would comingle with the chemical solution therein. Accordingly, during this operation the valves I I 4 are open so that the cleaning, solution entering vthe troughs 24 is discharged through the pipes I| and II2 into the header IIB, the valves |20 and |24 being closed at this time so that, for instance, such cleaning solution cannot find its way into the tank 28,

and the valve I|8 is open so as to permit the l cleaning solution to flow therethrough. The righthand end of the pipe I I8 is, as best indicated in Fig. 2, connected into the tank |80 so that the cleaning solution thus flows back into the tank |80 there to be withdrawn therefrom through the pipe I 84 and bel recirculated by the pump |88. A filter screen such as |88, shown in Fig. 2, within the tank |80 between the inlet and outlet openings thereof is preferably provided to aid in trapping the sludge which is picked up by the cleaning solution and may tend to be recirculated put in operation which thus initiates the circulation of the chemical solution from the tank 'I2 in the same manner as ,first described. Should, during the above described cleaning operation or otherwise, amounts of the chemical solution be lost from the system and require replenishment by quantities of new solution, the same may be suppliedv from a pair of containers such as 2|0, illustrated in Fig. 2, and mounted above the tank section 10 and provided with valve controlled spouts 2|2 through which additional amounts of the chemical solution may be discharged therefrom into the system.

therewith. This, of course, includes the Sludge or other foreign material which is removed from the

rolls

30 and 32 during the cleaning operation.

The cleaning solution is circulated as above described for a sufficient length of time to insure the desired degree of cleaning of the

rolls

30 and 32, whereupon the operation of the pump |88 is discontinued and the cleaning solution which has drained into the troughs |24 is allowed to drain back into the tank |80, whereupon the valves- I I8 and-|86 are closed.

As best indicated in Figs. 2 and 3, a fresh water supply pipe 200 having a shut-off valve 202 therein is connected into the pipe I 84 between the valve |86 and the inlet side of the pump I 88.

After the valves II8 and |86 have beenclosed the valve 202 is opened, the pump |88 is operated and, accordingly, fresh water is discharged by the pump |88 through the pipe |92 and header |84 into the header 58 and flows therefrom through the various connecting pipes through the nozzles and into contact with the

rolls

30 and 32 within this portion of the apparatus, from which it drains into the troughs 24. The valves I I4 still being open such water instead of overflowing the inner edges of thetroughs 24 and into the chemical solution in the bottom portion 22 and tanks 10 and 'I2 flows through the pipes I|0 and I|2 into the header IIB. 'Ihe'valve |20 is open at such time so that such cleaning water ows out of the lefthand end of the header I I8 as viewed in Fig. 2 and to a sewer or other suitable point of discharge. After the water has been allowed to flow through the piping and nozzles for a suilicient length of time to insure removal o1' substantially all of the cleaning solution, the valve 202 is closed. the operation of the pump |88 is discontinued, the valves |96, II4 and |20 are closed, and the valves 18 and 8| are opened and the pump 84 is again From the above description it will be understood that in accordance with the present invention means are provided for recirculating two different kinds of liquid through the system and for passinga third liquid through the system, and that means are provided for interrupting the circulation of the last-mentioned liquid at will and for interrupting the recirculation of either of the first two mentioned liquids in such a manner as to prevent contamination of one with the other and without the necessity of draining either of the last two mentioned liquids from the system but only from that part of the system common to both. It will, therefore, be appreciated that this method of operating such a system enables the cleaning of the

rolls

30 and 82 to 'be readily accomplished at desirable intervals and in a relatively short period of time as compared to practices heretofore employed.

The mechanism describedjn connection with Figs. 1 to 5', inclusive, is, of course. but one form of the mechanism by means of which the method of the present invention may be carried out and. in Figs. 6, 7, and 8 a different form of mechanism for the same purpose is shown. It will be understood that the mechanism shown in Figs. 6, 7, and 8 is a part of an entire mechanism such as illustrated in Fig. 1, substantially the only difierence being that portion of the apparatus included in and associated with-section A thereof. It will thus be understood that Fig. 6 is a vertical sec tional view of the apparatus lequivalent to the first apparatus shown in Fig. 3, that Fig. 7 is a view oi' the modified form of apparatus corresponding to the view shown in Fig. 2 and that Fig. 8 is a verticalisectional view of the modified form of apparatus approximately corresponding to the view shown in Fig. 5. In this modified form of apparatus the rolls equivalent to the

rolls

30 and 32 first described are here illustrated at 30a and 32a, respectively, a portion only of the member of such rolls being indicated in Fig. 6 by way of illustration and to simplify the drawings. The work I0a is` to be understood to be equivalent to the work i0 first described and pipes 82a are extended between the rolls 30a and 82a in the same manner as the pipes 52 in the first described construction and are provided with nozzles 50a (Fig. 8) such as the nozzles 50 in the first described construction. The rolls 30a 'and 32a are mounted between side walls 3|8 corresponding to the side walls I8 first described and having end walls 3|8 corresponding to the end walls I8 first described portion of the apparatus thus described is` positioned a solution reservoir or tank 322 and a cleaning solution reservoir er tank 324. To connect the spray tank thus formed by the side walls 316, end walls 3.116, and bottom walls 328 with the

tanks

322 and 324, the bottom wall 328 is centrally provided with a discharge connection 326 which, as best illustrated in Fig. 7, is provided withthree branches 323, 338 and 332 each one of which is provided with a. corresponding individually shut-

ofi

334, 336, and 338, respectively. The branch 328 leads into the tank 322, the branch 338 leads into the tank 324, and the branch 332 may lead to a sewer or other suitable point of dislongitudinally extending baille 348 is provided in theV tank 322 adjacent to but spaced from the opposite side thereof so that the solution must flow to the opposite end of the tank 322 vbefore it may return between the baffle 348 and such opposite side of the tank to the discharge pipe 342 connected thereinto on the side thereof opposit` the point of connection with the branch 328. Filter screens 344 are preferably provided between the baille 348 and the remote wall of the tank 322 in intersecting relation with respect to the path of flowvv of the chemicalsolution therethrough in order to intersect sludge which may be carried biy the solution, and heating coils 346 are preferably provided between the baille 348 and the near side of the tank 322 in order to heat the chemical solution being recirculated, in the same general manner as the steam coils l82 employed in the previously described construction. If desired an additional screen or filter 348 may be provided in intersecting relation with respect to the flow of solution from the heating coils 346 to the discharge line 342. Preferably a baille 358 secured to that end wall of the tank 322 through which the branch 328 is connected cooperates therewith to form a trough-shaped receptacle extendingr across the tank from the baille 348 to the remote side thereof toserve as a preliminary sludge settling chamber before the so-lution overows it"` upper edge and into the main portion of the tank 322.

The chemical solution which is discharged from the tank 322 through the discharg: pipe 342 is conducted to the inlet side of a suitably driven circulation pump 352 provided with a discharge pipe 354 which extends upwardly to above the upper edges of the side walls 316 of v the spray tank and is there joined to a connection 356 which in turn is connected by a nipple 358 to a header 368 which extends along the length of the spray tank portion of the apparatus and -is suitably connected to the various cross-pipes 52a. A shut-off valve 362 is provided in the discharge line 342 from the tank 322 and a shut-oil valve 364 is provided in the discharge pipes 354 of the pump 352 in closely adjacent relation with respect to the connection 356.

The tank 324 which serves as a reservoir for the cleaning solution is provided with a discharge pipe 318, provided with. a shut-01T valve 312 therein which leads to a suitably driven liquid circulation pump 314 provided with a discharge pipe 316 which extends upwardly and connects into theconnection 356 through the valve 318. A fresh water line 388 is also connected into the connection 356 through a valve 382.

With the understanding of the operation of the first described apparatus it is believed that the operation of the apparatus shown in Figs. 6

to 8, ionclusive, will be readily understood. In other words, during normal operation when the chemical solution is being employed for treating the work passing through the pairs of rolls 38a l the pump 352 is operating and the valves 334, Y

362 and 364 are opened while al1 the rest of the valves are closed. The chemical solution is thereby drawn from the tank 322 by the pump 352 and delivered to the pipe 354 through the connection 356 to the header 368 and then through the various pipes 52a and their cooperating spray nozzles 58a onto the surface of the work I8a, such solution draining from the rolls and the work onto the bottom surface 328 of the spray tank where it drains through the centery thereof and is discharged through the connection 326 and its branch 328 back into the tank 322.

When it is desired to clean the rolls 38a and 32a the pump 352 is stopped, the

valves

334, 362 and 364 are closed, the valves 336, 312 and 318 are opened and the pump 314 is put in operation. When the pump 314 is thus put in operation it causes the cleaning solution in the tank 324 to be withdrawn therefrom and discharged through the pipe 316 and connection 356 to the header 368 from whence it is distributed through the pipes 52a and their corresponding nozzles 58a onto the surface of the rolls 38a and 32a and then drained by the spray tank bottom walls 328 through the connection 326 and its branch 338 back into the tank 324 from which it may be again circulated. The circulation of the cleaning solution in this case is prevented from contaminating the chemical solution because of the scribed apparatus.

fact that the

valves

334, 362, and 364 are closed at this time.

When the cleaning solution has been circulated for a sufficient length of time to eiect the required cleaning of the rolls 38a and 32a the pump 314 is stopped, the

valves

336, 312, and 336 are closed, thus cutting off the cleaning fluid from the spray system, and upon which the valve 382 is opened to introduce 4fresh water under suitable Vpressure into the connection 356 and then through the header'368 to the various pipes 52a and their corresponding spray nozzles 58a from which it is directed to the rolls 38a and 32a and is then drained by the bottom wall 328 to the connection 326. The valvel 338 is opened under such circumstances and the wash or rinse water is thus discharged therethrough to a sewer or other suitable point ofdischarge. Following this operation the

valves

382 and 338 are closed, the valves 334 and 362 and' 364 are opened, and the pump 352 is resumed in operation, Whereupon the chemical solution is again caused to spray upon the work and the production of the apparatus continued.

As indicated in Fig. 8, a sludge tank |42a which may be identical to the tank |42 first described may be provided in connection with the apparatus disclosed in Figs. 6, '7, and 8 in substantially the same manner as in the case of the first defIhe sludge and sludge ladened chemical solutions which have been trapped back of the bal358 in the tank 322 and which has collected in the bottom portion of the tank 322 may be removed therefrom in substantially the same manner as in the rst described apparatus, or' by equivalent means, and discharged therefrom through a pipe such as l48a into the sludge tank I42a in substantially the identical manner employed in the construction first described.

It will thus be appreciated that while the apparatus illustrated in Figs. 6 to 8, inclusive, may be considerably different in detail from that first described, it may be operated in a similar manner to obtain the same identical results as the apparatus first described and may, therefore, be employed satisfactorily in place thereof.

- The use of the apparatus has been described in connection with the production of phosphatecoatings, but it will be understood that it may be employed where other coating processes encounter similar problems relating to sludge. In any case the cleaning will be effected by a solution having the desired effect upon the particular sludge formed in the particular process. For removing phosphate` sludge a solution containing phosphoric acid is preferred. A 25% solution oi phosphoric acid has been used successfully. The exact degree of acidity is not critical but in any case where the coating is effected by an acidulous solution, an acidulous cleaning solution, to be effective, should be more acid, or have a lower pH, than the coating solution. The cleaning solution does not necessarily contain the same kind of acid as the coating solution, but danger ,of contamination is lessened by employing the same kind of acid in both solutions, and it is the primary object of this invention to provide a simple method and apparatus by which sludge may be removed with a minimum of contamination of the coating solution.

What I claim is: i

1. In a method comprising the passing of metal between a succession of rolls and wetting it with a chemical solution during its passage, where the chemical solution is an acidulous one which reacts with the metal and forms insoluble salts of the acid part of which adhere to the metal as a coating, the steps which comprise applying said chemical solution to metal as it is passed through Vthe rolls, draining the solution from the rolls,

and directing the drained solution in one path and circulating it to where it again wets metal passing through the rolls, stopping the circulation of said solution, while said circulation is stopped applying to the rolls a cleaning solution containing the same acid as, but having a lower pH than, the said chemical solution and adapted to remove sludge from the rolls, draining the cleaning solution from the rolls and directing the drained cleaning solution in a path different from the first said Path.

2. In a method comprising the passing of metal` between a succession of rolls and wetting it with a chemical solution during its passage, where the chemical solution is an acidulous one which reacts with the metal and` forms insoluble salts of the acid part of which adhere to the metal as a coating, the steps which comprise applying said chemical solution to metal as it is passed through the rolls, draining the solution from the rolls, and directing the drained solutionin one path and circulating it to where it again wets metal passing through the rolls, stopping the circulation of said solution, while said circulation is stopped applying to the rolls a cleaning solution containing the same acid as, but having a lower pH than, the said chemical solution and adapted to remove sludge from the rolls, draining the cleaning solution from the rolls and directing the drained cleaning solution in a path different from the first said path, stopping the application of the cleaning solution to the rolls, and thereafter applying a rinsing liquid to the rolls, draining it therefrom and directing the drained rinse liquid in a third path.

3. In a method comprising the passing of metal between a succession of rolls and wetting it with a. chemical solution during its passage, where the chemical solution .is an acidulous one which reacts with the metal and forms insoluble salts of the acid part of which adhere to the metal as a coating, the steps which comprise applying said chemical solution to metal as it is passed through the rolls, draining the solution from the rolls, and directing the drained solution in one path and circulating it to where it again wets metal passing through the rolls, stopping the circulation of said solution, while said circulation is stopped applying to the rolls a cleaning solution containing the same acid as, but having a lower pH than, the said-chemical solution and adapted to remove sludge from the rolls, draining the cleaningsolution from the rolls and directing the drained cleaning solution in a path different from the first said path, and circulating it to where it is again applied to the rolls.

4. In a method comprising the passing of metal between a succession of rolls and wetting it with a chemical solution during its passage, where the chemical solution is an acidulous one which reacts wlth the metal yand forms insoluble salts of the acid part of which adhere to the metal as a coating, the steps which comprise applying said chemical solution to metal as it is passed through the rolls, draining the solution from the rolls,

and directing the drained solution in one path and circulating it to where it again wets metal passing through the rolls, stopping the circulation of said solution, while said circulation is stopped applying to the rolls a cleaning solution containing the same acid as, but having a lower pH than, the said chemical solution and adapted to remove sludge from the rolls, draining the cleaning solution from the rolls and directing the drained cleaning solution in a path different from the first said path,V circulating it to where it is again applied to the rolls, stopping the last said circulation, thereafter applying a rinsing liquid to the rolls, draining it therefrom and directing the drained rinse liquid in a third path.

5. In a method comprising the passing of ferrous metal between a succession of rolls, wetting the metal surfaces with a phosphate coating solution during its passage, draining the solution from the rolls to a collecting point, passing it from the collecting point in a path that circulates it to again wet metal surfaces passing through the rolls, stopping said circulation, thereafter applying to the rolls a cleaning solution containing phosphoric acid and more acid than said coating solution, draining the cleaning solution from the rolls to said collecting point, and directing the cleaning solution from said point in a path different from the said path of the coating solution.

6. In a method comprising the passing of ferrous sheet metal between a succession of rolls,

wetting the metal surfaces with a phosphate v said point in apath different from the said path 7. Apparatus for chemically coating sheet metal comprising a cooperating pair of rolls through which lsheet; metal may be passed, nozzles in position to apply liquid to said rolls, two separate reservoirs adapted to hold diierent solugtiQns, meansV to pump liquid alternatively'from saidfifreservoirsi-lt0;.f.,and through said nozzles, a

plate beneath said'll'lls in position -to receive liquid draining therefrom,l and means to direct liquid from said plate alternatively to said re'servoirs.

8. Apparatus for chemically metal comprising, in combination, cooperating pairs of rolls between which said metal is adapted to' be passed, a first reservoir, means for circulating liquid from said reservoir into contact with said rolls and the work passing therethrough,

means for collecting said liquid and returning it to said first reservoir, a second reservoir, means for circulating liquid ifrom said second reservoir into contact with said rolls and means for drain--l ing liquid from said second reservoir back to said Y second reservoir without comingling with the liquid in said iirst mentioned reservoir, the .iirst and third said means and the secondand fourth l said means having 'parts in common.

9. Apparatus for chemically coating sheet l metal comprising, in' combination;,cooperating pairs of rolls through which saidshet metal is adapted to be passed, a first liquid circulating system including a reservoir, a second liquid cii'-,A culation system includinga second reservoin said circulating systems including a portion com-v mon to both, at least a portion of said rolls being located in said common portion of said circulatory systems, and means for sealing'said common portion of said circulatory systems from the remainder of each of said circulatory systems.

k10. Apparatus for chemically coating sheet metal comprising, in combination, cooperating pairs. of rolls through which said metal is adapted to be passed, means for directing liquid under pressure' to said rolls, means for collecting said liquid applied to said rolls and drained therefrom, a first liquid reservoir, means for delivering liquid from said reservoir to said first mentioned means, a second r'servoir, means for delivering liquid from sa/id econd reservoir to f' 'said 'first mentioned means, means for separately sealing each of said last mentioned means from said first mentioned means, means for conduct- /ing liquid from said second ,mentioned means to Asaid rst reservoir, meansfor' conducting liquid from saidfsecond mentioned means to said second reservoir, and means for separately sealing'each of the two last mentioned means from said second mentioned means.

11. Apparatus for chemically coating sheet metal comprising, incomfbination, cooperating pairs o i rolls through which said metal is adapted A rfirst-mentioned means, means for separately seal- .coating sheet C,

ing each of said two last mentioned means from said iirst mentioned means, means for conducting liquid from said second mentioned means to said first reservoir, means for conducting liquid from 5 said second mentioned means to saidsecond reservoir, means for separately sealing each of the last mentioned means from said second mentioned means, means for delivering rinse water to said rst mentioned means, and means f or removing said rinse water from said .second mentioned means independently of both of said reservoirs. l 12. Apparatus for chemically coating sheets comprising, in combination, cooperating pairs of rolls between which said sheets are adapted to l be passed, means for directing liquid into contact with said sheets and rolls, trough means below said rolls, means for draining said liquid discharged rupon said work and rolls into said trough means, areservoir positioned to receive overflow from said trough means, means for, circulating liquid from said reservoir through the first mentioned means, a second reservoir,-

means` for sealing said circulating means from one anpther, and means for removing liquid from said trough meansv independently of said overflow and for selectively delivering it either to said rst mentioned reservoir or to said second mentioned reservoir. I

13. Apparatus for chemically coating sheets comprising, in combination, a tank, a trough arranged in overflowing relation with respect to said tank, means for draining liquid into said trough, cooperating pairs of rolls arranged above said drainingfmeans and adapted to receive said Work therebetween, a plurality of liquid discharge nozzles in position 'todischarge liquid u pon said 40 rolls and upon saidgwork passing therethrough, Y means for withdrawingliquid from said tank and' discharging it through jsaid nozzles,r a second tank, means for withdrawing Vthe liquid from said second tank and discharging it through said outlet- 14.?Apparatus for chemically coatingy sheets comprising, in combination, a tank, a trough arf ranged in overflowing relation with respect*l to said tank, means for draining liquid into said trough, cooperating pairs of rolls arranged above said draining means and adapted to receive said sheets therebetween, -a plurality of liquid dis-- charge nozzles in position to discharge liquid upon said rolls /and upon said sheets passing therethrough, means for withdrawing liquid from said tank and discharging it through said nozzles, a second tank, means for withdrawing the liquid from said second tank and discharging it through said nozzles, means for lsealing the vlast two mentioned means from each other, said trough having an outlet below said overflow, a

valve controlled passage from said outlet'to said second mentioned tank, means for closing said third Vmeans to the liquid in said second tank, means for connecting said third means to a source of rinse water, and a second valve controlled passage from said outlet.

15. Apparatus for vchemically coating sheet metal, comprising, in combination, a plurality of means. for circulating liquid fromsaidvsecond` reservoir through saidfirst mentioned vmeans,L

tank, and means for opening and closing said adjacent pairs of cooperating rollsproviding a work feed means, drain means positioned below said rolls for receiving liquid discharged from said rolls and the work passing therethrough, a

trough associated with said drain means for retion from said tank and delivering it through 10 said nozzles, a second tank adapted to receive a mixture of sludge and chemical solution and permit a separation thereof therein, a third tank, means for withdrawing liquid from said s third tank and delivering it through said nozzles,

and means for discharging liquid from a point below the overflow of said trough and selectively delivering it to said second mentioned tank, said third mentioned tank, or to a third point.

ERNEST W. RICHARDS.