US1849866A - Vessel for treating fibrous material - Google Patents

Description

March 15, 1932. T 4. J. DE LA @ZA SR 1,849,866

VESSEL FOR TREATING FIBROUS MATERIAL Filed Dec. 16, 1929 /@4; ATTORNEYS Patented Mar.'15, 1932 UNITED STATES JOAQUIN JULIO DE LA ROZA, $3., OF TUINUGU, CUBA VESSEL FOR TREATING FIBROUS MATERIAL Application filed December 16, 1929. Serial No. 414,610.

This invention relates to a vessel for treating fibrous material and, more particularly, to a vessel designed for treatin annual plants,

grasses, etc., with chemicals and heat, in the manufacture of cellulose.

The invention has for an object to provide such a vessel that may be charged and, emptied with economy and expedition.

Another object is to provide such a vessel that may be discharged at the end of the treating step without the necessity of waiting for it to cool.

Another object is to provide such a vessel which may be charged by means of baskets or the like adapted to contain the material and having substantially the same cross sectional size as the vessel, less sufiicient clearance to allow for the insertion and removal of the baskets.

' Another object is to provide such a vessel that is jacketed for the reception of a temperature controlling medium in order to attain and maintain the desired temperature of treatment, without obstructing the interior of the vessel and without bringing the heating medium in contact with the contents.

Another object is to provide such a vessel that includes means for guiding the baskets during their insertion and removal and for preventing injury which might result from contact of the baskets with the walls of the vessel.

Another object consists in providing certain improvements in the form, construction and arrangement of the several parts, whereby the above named and other objects may effectively be attained.

A practical embodiment of the inventlon 1s represented in the accompanying drawings, in which i Fig. 1 -represents a vessel;

Fig. 2 represents a vertical section taken in the plane of the line 11-11 of Flg. 1, looking in the direction of the arrows;

top plan view of the Fig. 3 represents a detail section, on an en- P g the guiding means and its fastening dev ces. The vessels, known as digesters,

lar ed scale, through one of hereinsuch as sugar cane, cornsta s, straw,

' and disadvantages above recited.

before commonly employed for the treatment of vegetablefiber under the action of chemi- 1 cal and heat to produce cellulose, have been restricted in cross sectional size at one or both ends and provided with openings for'charging and discharging, which openings have been of a size very much smaller than the cross sectional size of the interior of the vessels. This has been true whether the vessels have had an opening at only one end or at 00 both ends; and it may be specifically pointed out that, while these vessels-are frequently from six to twelve or fifteen feet in diameter,

a charging or discharging opening of two and one-half to three feet in diameter has 66 been the largest employed.

p These vessels, while apparently satisfactory for use in the production of cellulose from wood and the like by old and well known processes, have not been very success- 70 ful in the production of cellulose from annual plants, particularly with respect to discharging the vessels after treatment, because the matting or bridging of the fibrous material has required workmen to enter the vessels subsequent to a treating step and remove the charge. This procedure requires delay while waiting for the vessels to cool; it necessarily involves a slow rate of discharge; entails labor expense; and compels the workmen to operate under unhealthful conditions; as well 'as giving rise to other uneconomical or unsatisfactory factors.

The matting and bridging difficulty is accentuated when the material is only partly pulped in a given treatment, and is still further increased when manufacturing cellulose from such annual plants, for instance, as sugarcane. This last named material, unless fully cooked so that it is completely pulped, has a particular tendency to clogging the digesters and giving rise to the difliculties It has been suggested to so cook and dilute f 5 the material being treated that it might be umped or might flow from the vessel when desired, but this has not solved the problem and not only involves expense in itself but also prevents the digesters from being fully 1 charged with the material as the economics of the manufacture demand.

Such prior vessels have also been arranged to have a. temperature controlling medium, such as steam, applied thereto either by direct injection or by traversing a coil located within the vessel. Such arrangements have been found to be objectionable because, in the first case, the injection of the steam brings it in direct contact with the contents and tends to injure the same. Further, the increment of steam serves to dilute the strength of the chemical solution employed in the cooking treatment. In the case of the use of a coil, the interior of the vessel is partially obstructed so as to handicap charging and discharging and there is also a tendency to excessive local heating of that portion of the charge in contact with the coil. Furthermore, in connection with both of these prior practices, it has been extremely diflicult' accurately to maintain a predetermined temperature of the charge as a whole, which is a very important factor. I

My invention overcomes all these previous diiiiculties and disadvantages, and has desir able features of its own. Briefly stated, the invention comprehends so constructing a vessel of this character that its opening for charging and discharging is of substantially the same cross sectional area as the body of the vessel, and providing the vessel with a jacket for the reception of a temperature controllin medium, such as steam or hot water. Pref%rably, the vessel is substantially cylindrical throughout, and it-may be noted that my invention is applicable whether the vessel be of the stationary or of the rotary type.

Referring to the drawings, the body of the vessel is marked 1, and it may be composed of steel, iron, chrome nickel, or any other suitable material. If material is used that is not resistant to the chemical action engendered by the treatment, the interior of the vessel should be lined or coated with some material such as lead, chromium or cadmium. Brick of suitable character may also be employed. These materialsand their capacities for resisting chemica actions are well known to those skilled in this art.

The vessel is shown as cylindrical and of the same cross sectionthroughout. Its upper end is open and provided with an annular flange 2 for the reception of a dished cover 3 that is supplied with a ring 4cfor the purpose of handling the same, as by tackle or otherwise. The ring is preferably welded to the cover.

This cover 3 is also composed of suitable material for resisting the chemical action, and its periphery is arranged to be secured to the flange 2 by bolts 5 that traverse the same.

The upper and lower portions of the vessel may be provided with suitable inlets, outlets, or vents represented by 6, 7, which parts are also preferably composedof similar reshould likewise be resistant to the chemical action.

It will be understood that the provision of these last named parts is a matter of choice and engineering selection in any particular manufacturing plant and that the illustration and description just given ofthe parts 6--8 is intended conventionally to represent such details which may be varied to suit any particular requirements without affecting my present invention.

The body of the vessel is embraced by a jacket 9- which may beconstructed in any approved manner as, for instance, by welding. The said jacket is preferably composed of sheet metal of the same composition as the vessel and correspondingly resistant to the chemical action, and it may be secured at its bottom and top to the body of the vessel by welding.

In order to arrange for the circulation of a temperature controlling medium, such as hot'water or steam, within the jacket, the latter is fitted with inlet and outlet, 10, 11, which may be of conventional form and interiorly threaded for the reception of pipes.

As it is contemplated that this vessel is to be charged and discharged by the use of baskets of material, which baskets are in-' tended to be lowered into and'removed from trolling the movement of the baskets as they are inserted and removed and also prevent contact of the baskets with the wall of the vessel, which contact might result in injury. As shown in, Fig. 3, the said rails are preferably similar to small sized railroad rails and should be composed, as in the case of the above described parts, of material which will not be injured by the chemical action involved in the process carried on in the vessel. The said rails are removably secured in place by stud bolts 13, welded to the inner surface of the vessel 1, and provided with lugs '14 and nuts 15 for clamping the flanges of the rails. This arrangement permits the ready insertion and removal of the rails and thus not only facilitates construction, but

allows for repair and replacement when In operation, the vessel may conveniently be charged by packing the material in baskets, or the like, whichare of substantially the same size as the interior of the vessel, with the necessary allowance for the rails 12 and for clearance. The baskets may be lowered into the vessel by crane or other suitable means, and rest on a rack or upon the bottom of the vessel during the treatment. At the end of the treatment, the cover may be re-- moved by loosening the bolts 5 and lifting the cover away with tackle, and the basket containing the material may be lifted out of the vessel by similar means. This last named means, as well as the baskets, should be composed of such material or be so treated as to resist the chemical action involved in the process carried on in the vessel. This manner of charging and discharging is very effective and expeditious, and tends largely to overcome the previous disadvantages inabove recited.

The provision of the enlarged opening at the top of the vessel, which is in diameter at least more than one-half of the diameter of the body of the vessel and, preferably, equal to the diameter of the vessel, enables the rapid and effective charging and discharging of the vessel without the previous difiiculties; while the provision of the jacket for the circulation of the temperature controlling medium enables a predetermined temperature to be exactly attained and maintained, without any obstruction of the vessel, without any local overheating of the charge, and without any dilution of the chemical solution. While the j acketing feature is applicable to vessels of other form, and whether they have relatively large or relatlvely small openings, it is of particular advantage in connection with the form of vessel shown in this application, because it leaves the interior of the vessel free for the insertion and removal of a large and comparatively closely fitting basket of material. while providing adequate means for supplying uniform temperature throughout the charge. 1

It will be understood that various changes may be resorted to in the form, material, construction, and arrangement of the several parts without departing from the spirit and scope of my invention; and hence I do not intend to be limited to the details herein shown and described except as they may be included in the claim.

What I claim is:

A vessel of the character described, which is fitted to be charged and discharged by the insertion and removal of material-containing receptacles, comprising a body provided with a charging opening having an area substantially the same as the cross sectional area of the body, a cover for said charging opening, means for removably securing the cover in position, a jacket surrounding the body for containing a temperature controlling medium,

and vertically disposed guide rails located on the inner walls of the vessel for preventing contact between the receptacles and the walls of the vessel and for guiding the receptacles during insertion and removal.

In testimony that I claim the foregoing as my invention, I have signed my name this 12th day of December, 1929.

JOAQUIN JULIO do In ROZA, Senior.

here-

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