US1023458A - Pickling sheets, &c. - Google Patents

Description

s'. E. DIESGHER.

PIGKLING SHEETS,&0. APPLICATION FILED DEO.15, 1910. RENEWED SEPT. 9, 1911.

19233458.. Patented Apr. 16, 1912.

2 SHEETS-SHEET 1.

s. E. DIESGHBR.

PIOKLING SHEETS, 6m. APPLICATION FILED DBO.15, 1910. RENEWED SEPT. 9, 1911.

[1,923,45. Patented Apr. 16,1912.

2 SHEETS-SHEET 2.

FIRE.

" iiihli WITNESSES! 1 j INVENTOR SAMUEL E. DIESGHER, F PITTSBURGH, PENNSYLVANIA.

PICKLING SHEETS, 8w.

Specification of Letters Patent.

Patented Apr. 16, 1912.

Application filed December 15, 1910, Serial No. 597,531. Renewed Septemberfl, 1911. Serial No. 648,496.

To all whom it may concern:

Be it known that I, SAMUEL E. DmsoHER,

citizen of the United States, have invented or discovered certain new and useful Improvements in Pickling Sheets, &c., of which improvements the following is a specification. As is well known to those skilled in the art, it is the custom to use the acid bath until it becomes so supersaturated with a ferric compound as sulfate of iron, that the sheets or other articles are stained or discolored. The liquid is then drawn off and generally allowed to escape into the sewer, although in some instances steel scrap is added to the liquor after it has been drawn off from the pickling vat, so as to produce copperas which will crystallize and settle down.

As is well known the capacity of the liquor'to carry the salts formed is greatly increased by its constant agitation and its heated condition and hence the pickle bath can be used for some time after it has taken up sufficient iron to form if quiescent or at atmospheric temperature, a saturated solu tion. Hence if the excess of sulfate or other salt taken up by the bath after it has reached a condition of saturation if cold, be removed, such liquor could be again used if agitated or heated or both.

The object of the invention described herein is to provide for the removal of liquor from a bath, removing from this liquor the excess of sulfate or other salt and then returning such clarified liquor to the pickle bath.

The invention is hereinafter described and claimed. v

In the accompanying drawings forming a part of this specification Figure 1 is a view partly in elevation and partly in section of a form of apparatus suitable for the practice of my invention and Fig. 2 isa similar view of an apparatus for the practice of-a modification of the method.

In pickling sheets, etc., either the articles or the liquor are moved one relative to the other and in either case the liquor is kept on a state of agitation. And further in order to facilitate the cleaning action the liquid in the pickling vat is heated. By means of this agitation the liquor will hold in solution a quantity of the salts formed in pickling operation far in excess of the amount required toform a saturated solution. This carrying capacity of the liquor is increased by being heated.

In practice the liquor is used until it is so supersaturated that it stains the sheets or other articles. The term super-saturated as used herein is meant to specify the condition of the liquor, when it contains sulfate or other salt in excess of that neces sary to form a saturated solution when the liquor is cold or quiescent or both. It has been proposed to run the liquor when it has attained this supersaturated condition, into a storage vat, from which portions were to be drawn from time to time and subjected to a treatmentforremoving the salts in solution. This treatment consisted of boiling the liquor thereby evaporatin a portion of the water and proportionally lncr'easing the saturation of the liquor, which was then cooled to permit of the crystallization of the salts. This operation was repeated one or' more times in the expectation of removing all the saltsand producing sulfur acid of or sixty degrees strength, which was stored in carboys and might be used a second time in forming a pickle bath by diluting it with water. This method has never come into commercial use on account of the expense involved in the treatment and it is now the general practice to throw the supersaturated liquor away. This practice is not only wasteful as the liquor can be again used if the excess of salt be removed but is also very injurious as the liquor is generally discharged into rivers or streams killing the fish and rendering the water unfit for any use.

In the practice of my invention a portion of the liquor when the pickle bath approaches supersaturation is drawn off by a suitable pump '2 preferably by one of the pipe 5 to a steam generator. The water pro-- duced by condensation of the steam in the coils may be conducted by the pipe 6 to the vat 1 and used for diluting the acid. While flowing over the pans and coils there will be a considerable evaporation of the liquid eleried by bars 16 and liquor.

ment and a proportional relative increaseinthe salt carried by the liquor. From the lower pan of the series the heated liquor is conducted by a pipe 8 to a cooling and segline wlth the discharge end of the pipe 8.

The liquor is removed from the basin at a point or points .distant from its entrance into the basin, by any suitable means preferably by siphons 12 arranged to discharge into a trough 13 from which the liquor flows by the pipe 14 to the pickling vat 1. In the basin 1 the liquor is cooled to atmospheric temperature or lower if desired and although there will be a movement of the liquor toward the point or points of withdrawal from the basin, such flow will not be suflicient to prevent crystallization of the excess of salts on the pins 15 which are carroject down into the In this basin the conditions are such, 71. e. freedom from agitation and reduced temperature, as to facllitate the segregation by crystallization of all the salts in excess of the amount necessary to form a saturated solution which is returned to the vat where it will be agitated and heated and be capable of reuse until it has become again supersaturated.

While it is preferred to evaporate a portion of the liquor and thereby increase the relative quantity of salts carried by the liquor it will be understood that as the liquor in the vat is hot it may be pumped directly into the basin and there cooled to or below atmospheric temperature and allowed to as sume a quiescent condition. An apparatus suitable for this modified method is shown in Fig. 2 which shows the montejus connected. to a pipe leading to the basin.

In the practice-of method involving the evaporation of some of the liquor before segregation is efiected the evaporation causes arelative increase in the quantity of salts carried, by reducing the percentage of liquid. As is well known to those skilled in the art a liquor which cannot be used for cleaning sheets on account of the stains 1mparted to the latter, is still'capable of re- '-'ducing a considerable quantity of metal to salts which will be held in suspension as long as the liquor is hot and agitated. In the practice of my invention advantage is taken of this condition and scrap metal is added to the liquor after being withdrawn from the pickle vat and before it is so treated or placed under conditions as to permit of the segregation of the salts as described. After the scrap is dissolved in the liquor the latter is treated as hereinbefore described. By this method waste material is transformed into a merchantable article 2'. e. copperas without materially adding to expense of method of treating the liquor.

It is characteristic of my improvement ing additional quantities of the salts which.

are a valuable product. This is done by adding scrap to the liquor after it has been drawn from the vat as stated and then subjecting it to a treatment wherebythe excess of salts is eliminated.

While it is probable that the liquor will not be drawn from the vat until it has reached a supersaturated condition it will be readily understood by those skilled in the art that salts in solution may be removed from the liquor even though the latter has not 'attained even a saturated condition. This can be done by evaporating in the manner stated the liquid element of the liquor to such an extent that the liquor re-- maining after evaporation will be in a supersaturated condition or the relative increase of salts can be effected by adding scrap as stated and the excess of salts can be eliminated by cooling or keeping it in a quiescent condition or both.

It will be understood that in the method 7 herein described and claimed all of the salts contained in the liquor removed from the pickling vat are not removed, but only a certain percentage thereof, so that the mother liquor returned to the bath can be used in lieu of a certain percentage of fresh acid. The mother liquor will have about afour per cent. strength. It is preferred that the continuous flow from and to the.

pickling vat should be maintained and by properly regulatin this flow a constant operative condition 0 the pickle may be maintained, fresh acid being added as required to replace .what has been taken up by the salts and also fresh water to compensate for loss through evaporation and crystallization.

I claim herein as my invention:

1. The method of regenerating a pickling bath, which consists in drawing liquor from the bath, removing therefrom a portion of the dissolved salts, and returning the treated liquor to the bath. l

2. The method of regenerating a pickling bath, which-consists in drawing liquor from the bath, reducing the saturation point of such liquor thereby permitting of the segregation of the excess of salts carried by the liquor, and returning the clarified liquor excess of salts, and returning the liquor to p to the bath. the bath. 10

3. The method of regenerating a pickling In testimony whereof, I have hereunto set bath, which consists in drawing liquor from my hand.

5 the bath, changing the relative proportions SAMUEL E. DIESCHER.

of the liquid and salts carried by the liquor Witnesses: to lower the point of saturation of the liq- ALICE A. TRILL,

uor, permitting of the segregation of the THOMAS JOYCE.

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