US2697050A

US2697050A - Recirculation of waste pickle liquor

Info

Publication number: US2697050A
Application number: US100932A
Authority: US
Inventors: Barnes Roger Ray
Original assignee: Bethlehem Steel Corp
Current assignee: Bethlehem Steel Corp
Priority date: 1949-06-23
Filing date: 1949-06-23
Publication date: 1954-12-14
Anticipated expiration: 1971-12-14

Description

Dec. 14, 1954 R. R. BARNES RECIRCULATION OF WASTE PICKLE LIQUOR M WW7 M Q d 9 vvvlv m $8 I, NN 2 e n u 1? J G e l M Dec. 14, 1954 R. R. BARNES RECIRCULATION OF WASTE PICKLE LIQUOR Filed June 25; 1949 2 Sheets-Sheet 2 .lhvenior 6] fidfiarlzgs.

i Q UI Y w/ 1. J k. i. .1 i. {K i. i. 52 KE Twi Fig. 1 is a drawing showing in diagrammatic form a side elevation of apparatus embodying my invention for the pickling of continuous strip metal, and disclosing in schematic form a suitable strip actuating means as hereinafter referred to and described,

Fig. 2 is a drawing showing in diagrammatic form a side elevation of apparatus in part section illustrating a preferred embodiment of my invention for the pickling of continuous strip metal,

Fig. 3 is a plan view thereof with the metal strip and its actuating mechanism removed and showing in particular the recirculation flow of the pickling solution through the apparatus,

Fig. 4 is an enlarged fragmentary section of the overflow 29 taken along the line 44 of Fig. 3,

Fig. 5 is a plan view in full of Fig. 4,

Fig. 6 is an enlarged fragmentary section of the air-jet pump taken along the line 6-6 of Fig. 3, and

Fig. 7 is an enlarged fragmentary view taken along the line 7--7 of Fig. 6.

Referring now to the drawings and more particularly for the moment to Fig. 1, the numeral 10 designates the complete ensemble of an apparatus for pickling continuous strip metal embodying essential units of my invention. As shown in Fig. 1 the apparatus 10 comprises two substantially independent unitsa strip actuating means 11, and a pickling unit 12.

The strip actuating means 11 forms no part of my inven- I tion except to the extent in which it is an essential cooperating element along with the equally essential pickling unit 12 in a complete pickling system. The strip actuating means 11 in a pickling apparatus 10 embodying my invention may be of any suitable construction adapted to continuously pass metal strips through and submerged in a pickling solution of the pickling unit 12 per se, and therethrough in either direction with respect to the flow therethrough of the recirculating pickling solution. The specific showing of Fig. 1 with regard to this latter relationship of the strip actuating means 11 and of the pickling unit 12 is a modification of my invention and not a limitation thereto.

Typical strip actuating means are disclosed in Letters Patent 1,765,498 granted to Naugle et a1. June 24, 1930, and reference may be made thereto for the details thereof.

In Fig. 1 I have schematically indicated such a. suitable L strip actuating unit as including a guide roll 13 (7) from which the work strip 14 under treatment is here shown as being directed into the forward end of an elongated pickling tank 15 (8), and held in submergence therein in the pickling solution 16 (8a) by guide roll 17 (8b), and .1

supported therein on rolls 18 (80) while it is moving endwise therethrough. The work strip 14 is continuously drawn through the tank 15 (8) and leaves the opposite end thereof under the direction of guide rolls 19 (12a) and under the driving action of the power driven pinch rolls 20 (14). These elements are old and well known in the art, and the numerals appearing in parentheses are those used to designate the same parts in the above noted Patent 1,765,498, granted to Naugle et al., June 24, 1930, to which reference may be had for disclosure in full of a suitable strip actuating means 11.

In Fig. 1 I have shown my invention embodied in a pickling unit 12 comprising a single long tank 15. In Figs. 2 and 3 I show a preferred embodiment of my invention as applied to a pickling unit comprising a plurality of

pickling tanks

21, 22, 23, and 24 interconnected for liquid flow therethrough successively from the first tank 21 to the last tank 24 by means of interconnecting

pipes

25, 26, and 27 respectively. Itis obvious that the

pipes

25, 26, and 27 are unnecessary in Fig. 1, and since otherwise the apparatuses in Fig. 1 and in Figs. 2 and 3 are identical, that a description of my invention as applied to Figs. 2 and 3 will suflice for a clear understanding of its adaptation to the single long tank 15 of Fig. 1.

As shown in Figs. 2 and 3 the outgoing end of the tank 24 comprises the pipe 28 communicating the interior of the tank 24 with the interior of the safety overflow 29. Referring now to Figs. 4 and 5the safety overflow 29 comprises a pipe-like open-top container 30 having an inlet opening 31 from the pipe 28 near its bottom 32 thereof. Rising within the container 30 and attached to the bottom 32 thereof is .a smaller diameter open-top pipe 33 having its top peripheral edge 34 extending above the inlet opening 31 but spaced from and below the top 35 of the container 30. An emergency outlet overflow pipe 36 has its discharge opening 37 through the wall of the container 30 spaced from and above the top 34 of the pipe 33 but below the top 35 of the container 30. An outlet opening 38 in the bottom 32 of the container 30 and within the confines of the pipe 33 communicates the container 30 and the inner pipe 33 with the solution gravity flow interconnecting pipe 39.

The interconnecting pipe 39 (Fig. 2) slopes downwardly from the safety overflow 29 at the solution outgoing end of tank 24 to communicate with the connecting pipe 40 of the solution elevating piping 41 at the solution incoming end of tank 21. The solution elevating piping 41 comprises the connecting pipe 40 communicating the interconnecting pipe 39 with each of the two air-jet elevating pipes 42 and 43 rising vertically to outlet ends 44 and 45 respectively adapted to discharge into the solution incoming end of tank 21. At their lower ends the elevating pipes 42 and 43 extend downwardly below the connecting pipe 46 to communicate with the air pipe 46 and from air-jet pump chambers 47 and 48. The airjet pump structure is shown in enlarged detail in Figs. 6 and 7 for pump chamber 47 and is equally applicable for pump chamber 48. The air-jet pump chamber 47 comprises a diaphragm 49 disposed transverse the downward extension of the elevation pipe 42 and below the communicating opening 50 in the connecting pipe 413. The diaphragm 49 is perforated with a plurality of passageways 51 of relatively small diameter. Below the diaphragm 49 the pump chamber 47 is contracted to form a passageway 52 communicating with the air pipe 46. The air pipe 46 communicates with a source of air under pressure (not shown) and is provided with a control valve means 53.

My invention is adapted to utilize certain conventional operating means for the heating of the pickling solution, and for making withdrawals from and replacements to the said pickling solution in the tanks. As examples of such means the Figs. 1, 2, and 3 indicate for use in each of the tanks 15 of Fig. 1, and 21, 22, 23, and 24 of Figs. 2 and 3 of heating pipes 54 for injecting live steam into the pickling solution; acid pipes 55 and water pipes 56 for convenience in adding pickling solution; and drain pipes 57 for making pickling solution withdrawals from said vats. Each of the

pipes

54, 55, 56, and 57 are provided with suitable valve control means 58, 59, 6t), and 61 respectively.

The work strip of Fig. 2 is shown being guided into and out of the

individual pickling tanks

21, 22, 23, and 24 by strip actuating means similar to that shown in Fig. 1, and it is to be understood that when the pickling apparatus is in operation the work strip is being continuously passed through the pickling apparatus of Fig. 2 by similar means as shown and described for Fig. l, and its structure need not be here repeated.

In preparation for the pickling of continuous strip metal the pickling unit 12 of my invention will have been filled with suitable pickling solution to its operating capacity as determined by the height of the overflow peripheral edge 34 of the open-top pipe 33 of the safety overflow 29. In filling the tank or tanks of the pickling unit 12 the pickling solution will seek its level throughout the extent thereof including the safety overflow 29 in communication with the outgoing end of the tank system thereof. When the solution level in the unit 12 reaches the level of the overflow edge 34 and continues to rise the excess thereabove will discharge over the edge 34 and flow downwardly through the interconnecting pipe 39 to the solution elevating piping 41 at the incoming end of the tank system, and will then rise in the air-jet elevating pipes 42 and 43 until the solution level in unit 12 is reached. At this stage a slight operating excess is allowed in the unit 12 by setting the solution level therein at an intermediate height between the overflow edge 34 and the emergency overflow pipe 36 of the safety overflow 29 suflicient to maintain the continuous recirculation of the pickling solution within the pickling unit 12 at the capacity of the air-jet pumps when in operation. With the pickling unit 12 suitably filled with pickling solution it may be put into recirculating operation by opening the air control valve 53 to air pressure, thereby putting the air-jet pumps 47 and 48 into action, whereby the entire body of pickling solut1on 1n the pickling unit 12 is placed in continuous cyclical recirculating flow due to the discharge of the airet pumps flowing the pickling solution into the in .55 :com'ing end :of and rtlrrough the :tank system-mid successively nhrough the safdy overflow an, ithe anterconnecting pipe 39, the solution zelevating (piping 411, and {back again into 'lthe solution ain'coming .end sot ttheutank system, :and whence in :continuous ireptetition ot Jab-is cyclical necirculation ithrough 'the -piolling :unit

\Mith ithe pickling *unit E12 tin irecirculating operation and :the zpickling solution .properly .heated :to the desired temperature zby means iof ftheiheating pipes 54 under non- 11101 of the valves 58, .theLstrip actuating unit 111 znext .placed in operation to -continuously pass imetal :strip through and :submerged .-in the rpickling solution :of the pickling :unit '12.

.During ithe ipiolcling :operation 'titrations are :made at different points tinrthe yat systemxand at stated intervals of time. Based on Lt'heseobservationswithdrawals"drom tthe solution body and replacements itheeeto :of acid and water (are made in :suitable mroportions :to :modify and tain .the 'vat.capacity in balance.

ilclann:

,LApparatus for pickling continuous z-metal strip, comprising elongated tank .rneans adapted "with inlet piping means for continuously passing :a tregula'ted quantity of pickling solution into a first end of said tank means and with outlet piping means :continuously discharging :an equivalent quantity of pickling solution from its opposite end thereof whereby a continuously flowing ipickling bath is maintained therebetween, "means .fiior continuously passing metal .strip submerged in said ihath lztherethrough, interconnecting ipiping means communicatingtsaid .outlet .pipingtmeans with said inlet piping -means, said intenzonnecting .piping'means being adapted for energized .flow of pickling solution rtherethnnugh for delivery .to "saidinlet pipingmeans whereby pickling solutionin its entirety within saidapparatus is cyclically .maininined in continuous recirculation therethrough, and means for heating said picklingsolntion.

'2. Apparatus for pickling continuous metal striip, comprising a plurality of pickling tanks suitably interconnected for continuous liquid flow successively from a first one to a last one thereof, said first one of said tanks being adapted with inlet piping means for continuously passing a regulated quantity of pickling solution into said first tank, and said last one of said tanks being adapted with outlet piping means for continuously discharging therefrom an equivalent quantity of pickling solution to that received in said first tank whereby a continuously flowing pickling bath is maintained flowing successively through said tanks, means for continuously passing said metal strip submerged in said bath through each of said tanks, interconnecting pining means communicating said outlet piping means with said inlet piping means, said interconnecting pi ing means being adapted for energized flow of ickling solution therethrough for delivery to said inlet piping means whereby the pickling solution in its entirety within said apparatus is cyclically maintained in continuous recirculation therethrough, and means for heating said pickling solution.

3. Apparatus for pickling metal, comprising elongated tank means adapted with inlet piping means for continuously passing a regulated quantity of pickling solution into a first end of said tank means and with outlet piping means for continuously discharging an equivalent quantity of pickling solution from its opposite end thereof whereby a continuously flowing pickling bath is maintained therebetween, said outlet piping meanscomprising means for maintaining anoperating solution level in said tank means, means for continuously passing metal submerged in said bath therethrough, interconnecting piping means communicating said outlet piping means with said inlet piping means, said interconnecting piping means being adapted for energized flow of pickling solution therethrough for delivery to said inlet piping means whereby the pickling solution within said apparatus is cyclically maintained in continuous recirculation therethrough, and means for heating said pickling solution.

4. ApParams rtfor rpickliug montimrons @metal astrip, comprising elongated :tank means adapted *with .inlet piping tmeans'tfur econtinuousiy passing/a regulated quan- :tity tof piokling'isolution time a s'first tend iof said tank :means and With outlet piping imea ns for continuously .disrchargingtamequiva'lent quantitysof ipicld ing solution from :its topposite endlthereof'vtiherehty5. a :continnouly flowing :pio'lfiling bath maintained 'itherebetween, said :outlet :piping means comprising nneans :fonmaintaining an open :atiugrsolution level :in said tank means, means ."for :con- .sinuously passing metal .tstrip submerged in said bath zth'erethrongh, 'intencon'neoting .miping uneans communicatingusaid .outl'et ipipirr-g means with tsaid linlet piping means, said interconnecting tpiping :means being :adapted *for energized flow :of rpiokling solution trtherethrou'gh for -:delivery r-to 'saidtinlet :piping :means whereby the :p'ickling solution said apparatus iszcyelically maintained in continuous :reoirculation :there'throug h, and means to heating .sai'd iSUlllti'QIl.

5. Apparatus for pickling continuous metal strip, com- 'prisingia plnralitytofxpicktlingfrankssuitably interconnected "for continuous liquid jfl'ow successively from a first tone rto Ja il'ast lone (thereof, iiirstcone of said :tanks -Ibein-g ndapted with'inlet ;piping:means for continuously passing a'megulated quantity of :pic'kling isolution into said PfiI'St tank, last one of isaid tanlcs rbeing adapted with outlet ipiping means :for continuously discharging there- .Jfinorn tan equivalent quantity 'nfupiokling ssolution to that -rene'ive'd inssaid tan'k' whereby a continuously flowing pickling bath is maintained flowing successively through said rtanks, outlet ipipiug means comprising means lfiorxmaintairiing amtoperatin g zsohltion'leve'l insaid tanks, means :for :continnously passingsaidmetal s'tmiprsubmerged tin dxath tt-hnongh each of ;said=tanks, interconnecting piping means uommuniicating said outlet piping :means with :said Llml'et :piping means, :said interconnecting :piping --:means beingradapted for energized flow :of pickl ing soluition therethmoumgh forv'deliverytto ssaid inletpiping means whereby tthe pickling solution 'within said :apparatus is -cyolically "maintained in continuous recirculation therethrough,;and: means for heating said pickling solution.

:6. .A pparatusrfior pickling .metal, comprising elongated .ztan'k means adapted with inlet piping means for con- :tinuously tpassing -a'neguilated quantity of pickling solution into .afirst ffiTlGltOf said Ita'n'k means and with zoutle't piping ntreans ifiomxontlirruously dischargingiia-n equivalent quant ity nftpiclalingzsoiution ifrom sitar-opposite end thereof whereby a continuously flowing pickling bath is maintained therebetween, said outlet piping means comprising means for maintaining an operating solution level in said tank means and means for discharging to waste abnormal excess solution level therein, means for contifiuously passing metal submerged in said bath therethrough, interconnecting piping means communicating said outlet piping means with said inlet piping means, said interconnecting piping means being adapted for energized flow of pickling solution therethrough for delivery to said inlet piping means whereby the pickling solution within said apparatus is cyclically maintained in continuous recirculation therethrough, and means for heating said pickling solutron.

7. Apparatus for pickling continuous metal strip, comprising elongated tank means adapted with inlet piping means for continuously passing a regulated quantity of pickling solution into a first end of said tank means and with outlet piping means for continuously discharging an equivalent quantity of pickling solution from its opposite end thereof whereby a continuously flowing pickling bath is maintained therebetween, said outlet piping means comprising means for maintaining an operating solution level in said tank means and means for discharging to Waste abnormal excess solution level therein, means for continuously passing metal strip submerged in said bath therethrough, interconnecting piping means communicating said outlet piping means with said inlet piping means, said interconnecting piping means being adapted for energized flow of pickling solution therethrough for delivery to said inlet piping means whrereby the pickling solution within said apparatus is cyclically maintained in continuous recirculation therethrough, and means for heating said pickling solution.

8. Apparatus for pickling continuous metal strip, comprising a plurality of pickling tanks suitably interconnected for continuous liquid flow successively from a first one to a last one thereof, said first one of said tanks being adapted with inlet piping means for continuously passing a regulated quantity of pickling solution into said first tank, and said last one of said tanks being adapted with outlet piping means for continuously discharging therefrom an equivalent quantity of pickling solution to that received in said first tank whereby a continuously flowing pickling bath is maintained flowing successively through said tanks, said outlet piping means comprising means for maintaining an operating solution level in said tanks and means for discharging to waste abnormal excess solution level therein, means for continuously passing said metal strip submerged in said bath through each of said tanks, interconnecting piping means communicating said outlet piping means with said inlet piping means, said interconnecting piping means being adapted for energized flow of pickling solution therethrough for delivery to said inlet piping means whereby the pickling solution within said apparatus is cyclically maintained in continuous recirculation therethrough, and means for heating said pickling solution.

9. A process for the pickling of metal continuously passing immersed through a pickling bath, comprising the energizing of the pickling solution of said pickling bath in its entirety for continuous cyclical recirculation through said bath and for repetitively immersed contact with said metal, and regulating the chemical characteristics of said pickling solution by making periodic withdrawals from and replacements thereto of predetermined volumetric and acid concentration values thereof during said pickling operation.

10. A process for the pickling of strip metal continuously passing immersed through a pickling bath, comprising the energizing of the pickling solution of said pickling bath in its entirety for continuous cyclical recirculation through said bath and for repetitively immersed contact with said metal strip, maintaining a substantially uniform regulable temperature of said pickling solution, and regulating the chemical characteristics of said pickling solution by making periodic withdrawals from and replacements thereto of predetermined volumetric and acid concentration values thereof during said pickling operation.

11. A process for the pickling of metal continuously passing through a longitudinally disposed pickling bath, comprising the heating of and the energizing-for-fiow of the pickling solution of said pickling bath in its entirety for continuous unidirectional cyclical recirculation through said bath and through bath terminals interconnecting return conduit therefor, thereby effecting uniform heating of said pickling solution and repetitively immersed contact thereof with said metal.

12. A process for the pickling of metal continuously passing through a longitudinally disposed pickling bath, comprising the heating of and the energizing-for-fiow of the pickling solution of said pickling bath in its en tirety for continuous unidirectional cyclical recirculation through said bath and through bath terminals interconnecting return conduit therefor, thereby effecting uniform heating of said pickling solution and repetitively immersed contact thereof with said metal, and regulating the chemical characteristics of said pickling solution by making periodic withdrawals from and replacements thereto of predetermined volumetric and acid concentration values thereof during said pickling operation.

13. A process for the pickling of metal continuously passing through a longitudinally disposed pickling bath, comprising the heating of and the energizing-for-flow of the pickling solution of said pickling bath in its entirety for continuous unidirectional cyclical recirculation through said bath and through bath terminals interconnecting return conduit therefor, thereby effecting uniform heating of said pickling solution and repetitively immersed contact thereof with said metal, maintaining a substantially uniform regulable temperature of said heated pickling solution, and regulating the chemical characteristics of said pickling solution by making periodic withdrawals from and replacements thereto of predetermined volumetric and acid concentration values thereof during said pickling operation.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,544,506 Tytus June 30, 1925 1,718,063 Naugle June 18, 1929 1,837,159 Fellows Dec. 15, 1931 1,943,775 Taylor Jan. 16, 1934 1,999,822 Nieman Apr. 30, 1935 2,135,713 Higgins Nov. 8, 1938 2,216,544 True Oct. 1, 1940 2,234,593 Ferm et al. Mar. 11, 1941 2,314,369 Reed Mar. 23, 1943 1 2,529,762 Brisse Nov. 14, 1950

Claims

11. A PROCESS FOR THE PICKLING OF METAL CONTINUOUSLY PASSING THROUGH A LONGITUDINALLY DISPOSED PICKING BATH, COMPRISING THE HEATING OF AND THE ENERGIZING-FOR-FLOW OF THE PICKING SOLUTION OF SAID PICKLING BATH IN ITS ENTIRETY FOR CONTINUOUS UNIDIRECTIONAL CYCLICAL RECIRCULATION THROUGH SAID BATH AND THROUGH BATH TERMINALS INTERCONNECTING RETURN CONDUIT THEREFOR, THEREBY EFFECTING UNIFORM HEATING OF SAID PICKLING SOLUTION AND REPETITIVELY IMMERSED CONTACT THEREOF WITH SAID METAL.