US477755A - hinisch - Google Patents

Description

(No Model.) 3 SheetsSheet 1.

G. E. HANIS'OH. BOILING AND PREOIPITATING TOWER. No. 477,755. Patented June 28, 1892.

(No Model.) 3 Sheets-Sheet 3.

G. E. HANISUH BOILING AND PRECIPITATING TOWER.

No. 477,755. Patented June 28, 1892.

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1 UNITED STATES PATENT OFFICE.

GUSTAV EMIL I-IANISCH, OF BEIITHEN, GERMANY.

BOILING AND PRECIPITATING TOWER.

SPECIFICATION forming part of Letters Patent No. 477,755, dated June 28, 1892. Application filed March 3, 1890- SerialNo. 342,400. (No model.)

To all whom it may concern:

Be it known that I, GUSTAV EMIL HANIscH, a subject of the King of Saxony and German Emperor, residing in the city of Beuthen, German Empire, have invented certain new and useful Improved Boiling and Precipitating Towers; and I do hereby declare that the following is a full, clear, and exact description of the invention, which will enable others skilled in the art to which it appertains to This invention relates to boiling and pre cipitatjng towers or columns for carrying out various chemical processes in which precipitates are obtained from any kind of solution by the introduction of steam or gas, &c.

It has for its object to providea boiling and precipitating tower which may be worked regularly and continuously for a certain time and which can be completely discharged and cleaned out withoutloss of time or of the substance treated in the tower.

The invention consists in a construction of the boiling and precipitating tower in two chambers or divisions, so that the one chamher for the boiling-out or precipitating process, closing air-tight and provided with fittings suitable for the purpose, is separated from the other chamber, serving as a passage of access and also closing air-tight by a partition formed by closely-shutting plates or doors located one above another.

In the accompanying drawings, Figure 1 is a vertical section of a boiling and precipitating tower embodying this invention; Fig. 2, a vertical section through line A B of Fig. 1; Fig. 3, a vertical section of a portion of the tower to an enlarged scale; Fig. 4, a horizontal section through line C D of Fig.3; Fig. 5, a vertical section through a portion of the tower with wood blocks arrangedtherein.

The tower consists, substantially, of a boarded shaft of considerable height and root angular in cross-section. The inside of the tower is lined with sheet-lead 1 and made airtight. The tower or boarded shaft is constructed in two divisions or chambers.

E is the chamber in which solutions or lyes are boiled orprecipitates obtained therefrom, to which end it is fitted with inclined planes 2, Fig. 2,'or has wood bars 3, Fig. 5, arranged in it. The other chamber F is without fittings and serves simply as a passage for the workman engaged in clearing out the boiling and precipitating chamber E. The two chambers .are separated by a partition made up of single wood plates or planks 4, standing one above another, lined or covered with lead on the inner or chamber E side, and closing airtight, these plates 4 being held pressed against the shaft-frame by props 5, the edge bearingsnrfaces, as well as the butt-joint surfaces of the plates 4, being covered with india-rubber, so as to render a hermetical closure practicable. I

If the tower is intended for the treatment of alkaline instead of acid solutionsas, for instance, for the boiling or evaporation of weak ammonia-water with addition of milr of limeit may be constructed of plate-iron instead of wood with a lead covering.

In order that it may not be necessary to remove the whole of the partition from top to bottom when, as may frequently happen, a stoppage or blocking up of the tower takes place at any part of its height, square iron bars 6, covered with lead, are interposed at certain distances apartsay from two to three yardsto act as bearers each for from four to six plates or planks 4. In order, also, to prevent the necessity of removing the wood bars 3 for the purpose of clearing out the tower, these must not be placed to cross each other, but must all lie in the same direction, with their ends toward chamber F, to allow of the precipitate being withdrawn by means of a long iron tool.

In order, when the cleaning or clearing out operation is in progress, to prevent the precipitate from falling down and accumulating at the bottom in a way to stop up the apparatus, the wood blocks in such a kind of in ternal arrangement as shown in Fig. 5 are arranged in sets from two to three yards high, one set above the other, each set being separated by a clear distance of about nine inches. In the clearing-out operation a board the shape of the cross-section of the tower is slid underneath a set and receives the falling material. The solutions or lyes from which precipitates are to be obtained pass into the tower through pipe '7. The steam or prec=ipitating gases enter through pipe 8. The waste gases pass away through pipe 9. The precipitaies, &c., are dischargedthrough pipe 10. The lye, formed with the precipitate to a thin paste flowing out of the tower, with addition of lye from the tower, collects in a settlingtank, Fig. 2, placed lower down. The preoipitate settles to the bottom sooner or later, according to its specific gravity, while clear liquid flows off continuously through upper overflow-pipell. Processes of thiskind have hitherto generally been carried out in fixed cylinders or casings, several of which are combined so as to form one apparatus. though this method of working is said to be continuous, yet each element of the apparatus is in turn thrown out of work, and to charge and empty it it must be disconnected from the other elements, during which time its operation isstopped. 'lherefore,instead of such apparatus it is more advantageous and convenient to employ high boilin g-towers, which allow of a very regular and for a certain time continuous working. In conjunction with small attendance requirements, regularity of working, and profitable consumption of steam or gases ascending from below, there are-two very important properties possessed by boiling-towers as compared with cylinders and which for certain processes are of great importance and economic value. Taking, for example, the boiling out of a solution of phosphate of lime in sulphurous acid-such as is obtained in the process of extraction from bones by means of sulphurous acid-it has been observed that in the boiling process expulsion of the sulphurous acid as pure gas and precipitation of the phosphoric acid as terphosphate of calcium, there has been in practice the great drawback in the use of evaporating-vessels that the most important evolution of sulphurous acid taking place between and 90 Celsius of temperature causes such a violent soap-like froth-l ing that the larger portion of the charge has;

to be thrown over to the next vessel of the combined apparatus. The frothin g then takes place to a greater extent in the second vessel,

greater still in the third, and so on, as each,

successive vessel has an increased charge. Therefore in practice, in order to avoid frothing over either, very high vessels are used, or:

these must be worked with a charge of onethird or one-quarter their capacity.

vantage that the air entering the vessel every time it is charged, say, to the extent of three phosphate solution of 16 Baum strength,

the precipitate contains from fifteen to sixteen per cent. of sulphurous anhydride and the residual lyethat is, the liquid remain- This course, however, presents the great disading behind after the process of precipitation from 0.5 to 0.6 per cent. of sulphurous acid, while the boiling out of a similar solution in the tower during a space of time of almost two minutes yields a precipitate containing only from seven to eight per cent. of sulphurous acid, corresponding to the quantities of the earths and alkalies present, and a residual lye with only 0.25 per cent. of sulphurous acid. Consequently the performance of the precipitating process in the tower is, in addition to continuous working and a much lower expenditure of steam, of advantage from a double point of view, as, first, the expelled gas-sulphurous anhydrideafter condensation of the steam is obtained only in a pure state, and, secondly, the precipitate-is almost perfectly free from sulphurous acid.

There are several chemical processes quite analogous to the example cited. In most cases the employment of towers would be preferred for the boiling or treatment of lyes or solutions with gases were it not for an important drawback which has hitherto been the cause of such towers being advantageous to a small extent only. This drawback consists in their liability to a more or less frequent stopping up of their fittings or passages by the formation of sludge, which renders it necessary to put them out of operation for their thorough discharge and clearing out. Attempts have been made to get over the diffieulty of the clearing of the internal fittings or to render this easier by arranging at the sides of the tower large cleaning-apertures closable with plates and screws; but in this case the clearing out can only be imperfectly accomplished, especially when the sludge cakes to hardness, as it does in many boiling processes. There is also the evil that the large number of cleaning-apertures required are very difficult to keep tight, and consequently lead to a loss of as.

b In order to allow of boiling and precipitatin g towers of the kind referred to being easily and thoroughly cleared out without much loss of time and. without removal of the internal fittings, I construct and operate them as here inbefore described.

The difficulty of properly closing the cleaning-apertures has led me to the construction of my double chamber boiling and precipitating tower, the essential feature of which is the removable partition composed of plates- Wall composed of removable tightly-closing ing toward said side or wall of shaft E, subplates located one above another, in combinastantially as described and shown. L tion with a fixed bearer to each set of from In testimony whereof I have signed tins four to six plates, substantially as described specification in the presence of two subscrib- 5 and shown. ing witnesses.

3. In a boiling and precipitating tower, a

GUSTAV EMIL HANISCH. shaft E, with a side or wall composed of separate removable tightly-closing plates located Witnesses: one above another, in combination with par- PETER SPREoKELs,

1o allel wood bars located with their ends point- PAUL DRUOKMI'JLLER.

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