USRE22814E

USRE22814E - Apparatus for continuous

Info

Publication number: USRE22814E
Authority: US
Priority date: 1940-07-30
Publication date: 1946-12-03
Also published as: US2307154A

Description

I5 Sheets-Sheet` l Dec. 3, 1946. J. R. osUNA APPARATUS FOR CONTINUOUS CLARIFICATION Original Filed July 10, 1941 f/v VEN TOR.

A T To /efvfys l2/ /20 glA Dec. 3, 1946.

.1. R. `osLJNA APPARATUS FOR CONTINUOUS CLARIFICATION original Filed July 1o, 1941' s sheets-Sheet 2 ,a vjNvfNrok. l

Dec. 3, 1946. J. R. osUNA Re 22,814

` APPARATUS FOR CONTINUOUS CLARIFICATION Original Filed July` 10, 1941 3 Sheets-Sheet 3 A T TORNEYS Reissued Dec. 3, 1946 ernannt-:Us FOR CONTINUOUS CLARTFICATION .lose Ramn Gsuna, Marianao, Cuba @riginal No. 2,307,154, dated January 5, 1943, Se-

rial No. 401,824, July 10, 1941. Application for reissue December 3, 1943, Serial No. 512,761.

In Cuba July 30, 1940 7 Claims. l

The method heretofore employed in the man facture of sugar and particularly in the sugar refining operation, consists in subjecting the syrups formed by dissolution of washed or affinated raw sugar to a purification process which is carried out as follows: The washed or ailinated sugar is dissolved in water in tanks provided with agitators to form a syrup with a density of 60 Brix, and the syrup obtained is purined by treatment with chemical. agents and heat. The solutions thus treated are discharged into open tanks (defecatcrs) to be subjected to claritication by decantation. The number of defecators or tanks is dependent upon the amount oi material to be treated in 24 hours and upon the time required for obtaining the clariiioation in each tank. In the case of dense solutions which are the ones being usually treated at sugar reiineries, the average time required for decantation varies from 45 to 60 minutes and sometimes more, depending upon the liquid level, density and temperature.

The processes heretofore employed require the temperature to be raised sometimes even to above 216 F. in order that the floccules formed may rapidly ascend to the liquid surface and properly separate after they have overcome the weight of the liquid upon them. It is just in this stage that the so-called manufacturing losses occur,

which are caused by the heat affecting the sucrose and tending to invert it thereby yielding a greater percentage of molasses to the factory; heat also causing the liquid to become darkened on account of the candied condition of sucrose, and the use of additional decoloring agents being required in a further decoloring operation in order to obtain a No. 1 liquor from which reiined sugar is obtained as the final product.

vbetween 2e" andG, a temperature diierence. oi

3 C. or more below the corresponding vacuum temperature, being used. Said 3 C. temperature difference is used for the purpose of preventing the liquid from boiling for it is a well known fact that every liquid attains a boiling point according to the pressure acting upon same.

The advantages possessed by my clarification method and apparatus are, in the case of refinery syrups, that these can be clarified at a lower temperature than is at present required, without danger of increasing the darkness of color, and an increase of velocity is attained which permits to treat a larger quantity of material in the same period of time with smaller tanks and in a shorter period of treatment, whereupon a considerable reduction is obtained in the losses on in- 2 version which occur under the methods at present known.

The invention is described with reference to the figures of the accompanying drawings, of which:

Fig. l is a diametral vertical sectional view of a continuous clarifier and attachments thereof for carrying out the clarification method beingI the vsubject-matter of this invention.

Fig. 2 is a top plan view of same.

Fig. 3 is a longitudinal vertical sectional view of the level regulator on line 3 3 of Fig. 2.

Fig. i is a fragmentary outer elevational view of the tray forming the upper chamber of the clarifier'.

Fig. 5 is a fragmentary top plan View of the same tray.

Fig. 6 is a vertical cross-section view on line 5-6 of Fig. 4.

Fig. 7 is a detailed view showing in a broken longitudinal vertical section the level regulator annexed to the continuous clarifier and the latters connection with the former.

Fig. S is a detailed edge view of an arm agitator used for the liquid surface with the clariiier.

Fig. 9 is an elevational' detailed View of the same arm agitator.

Fig. l0 is a vertical cross-section detailed view on line lil-l0 of Fig. 9.

The method of clarification being an objectof which the liquid iiows upwardly, impurities deposited above the liquid level being eliminated and the partial withdrawal of clarified liquid being effected at the lowest Zone of each compartment, in contrast to the clarification methods at present known in which the liquid ilows downwardly, the mud is withdrawn at the bottom and the partial removal of clarified liquid is veffected at the upper zone of each compartment.

In the drawings is illustrated a clarifier device for carrying out the method of this invention, and possibly others, which device consists of a cylindrical tank l closed at ythe top, the upper portion of which is conical in shape and its bottom portion is in the shape of an inverted cone. The bottom of tank l is provided with a register opening 2 having a pressure cover 4and a feed-tube 3 for the liquid to be claried, said feed-tube 3 ending in .the form of an inverted syphon at a predetermined heightfrom the bottom, and the bo-ttom of the tank I has also a central opening and therein a discharge tube 4 provided with a controlling valve 5. The tank is divided interiorly into a lower flocculatio-n chamber 6, an' upper sludge discharge chamber l and an intermediate series of clarifying chambers a, by means of a plurality of annular bailles or trays 9 of frusto-conical shape or sloping from the center to the periphery. Said trays are secured at their outer edge to the peripherial wall of tank I and each has an upstanding cylindrical portion 9 at their upper open portion to permit the liquid to pass upwards along the central line of tank I. Each compartment 8 is provided at the peripherial Wall of tank I with a register opening I Il for cleaning purposes at one side thereof and at the other side each compartment has a small opening and a discharge tube II provided with a controlling valve I2 for the liquid claried in the lowest Zone of each compartment. The tray 9 serving as a bottom portion for the sludge upper discharge chamber 1 has a vertical cylindrical portion 9" which is higher than the vertical cylindrical portions 9 of the lower trays and is provided with four openings I3 near its upper portion which is crossed by a diametral partition I4 dividing the cylindrical portion in two half portions laterally opened in a bottom inclined radial conduit I5 (Fig. 4) terminating at .the peripherial wall of tank I in an opening provided with a discharge tube I6 for the sludge separated from -the liquid surface. At the upper central portion of the tank I is rotatably mounted on a bearing I1 a vertical shaft I8 supported at its lower end on a bearing I9 integral at the middle portion of partition I4. The vertical shaft I8 is provided at its lower end with agitator arms formed by vertical blades 20 in diametral alignment from which other vertical parallel blades 22 are hanging through rings 2|, the vertical shaft I8 .being rotated at a very slow speed by means of a horizontal helicoidal wheel 23 actuated by a worm gear 24 coupled Ito the shaft of an electric motor 25 supported on the upper portion of tank I. The upper portion of tank I has a large opening 26 for connection `with the suction pipe 21 communicating with a vacuum condenser which is not shown, for maintaining sub-atmospheric pressure on the surface of the liquid in the tank and at said upper portion of tank I there are also disposed a vacuum manometer 28 and a tube with a controlling valve 29 for communicating the interior of rtank I with the atmosphere, when desired.

The tubes I I for discharging Vthe claried liquid in the lowest zone of the intermediate compartments 8 and the upper chamber 1 are connected to vertical tubes, conduits, or pipes 30 the number of which is equal to that of tubes I I, lthree of said tubes being indicated in Athe drawings. Said tubes 30, each hold a column of liquid normally in hydraulic communication with the body of liquid l being treated in the tank I, rise up to a predetermined height above the bottom portion of a control chamber or closed box 3| supported on a bracket 32 secured exteriorly to .the peripherial wall of tank I, and each tube 30 is provided withv a controlling valve 30'; On the upper, portions of .the three .tubes 30 are slidably mounted cylindrical sleeves 33 which lit on tubes 30 and form at their upper ends discharge openings the height of which is adjusted by means of clamps 34 secured to the sleeves 33 and connected Vto vertical screws 35 threadedly mounted in nuts 36 rotatably mounted on the upper .portion of box 3 I, the object of said three vertically slidable discharge sleeves 33 being to control the discharge height of the liquid falling from tubes into an overflow liquid receiving space outside of `the main wall of the tank I, such as is provided by box 3I and therefore the level of the liquid within the upper chamber. 1 of tank I. The box 3| is provided with a clarified liquid discharge tube 31 leaving from the bottom of the box and leading downwards to end in a collector tank (not shown) disposed far beneath the tank I, said collector -tank being completely sealed to maintain the required vacuum in the system. The tube 31 has a horizontal branch tube 38 connected to the three vertical tubes 30 by means of the horizontal tube 39 and said tube 38 in turn extends to form a vbranch tube bent twice at an angle as indicated by 40 and has a controlling valve 4I beneath the bottom of tank I. Through the bottom of tank I two tubes 42 each having a controlling Valve 43 extend upwards to be connected at the end of the branch tube 40 and terminate at their upper open end near the tray 9 which serves as a `cover for the ilocculation chamber 6, the function of said tubes being to serve as outlets for the clarified liquid when the clarifier is emptied for cleaning purposes. The level controlling box 3| is in communication with the vacuum or suction pipe 21 through a suction tube 44 having a controlling valve 45 and leading from the upper portion of the box 3 I.

The method of continuous vacuum clarication is carried out by means of the described apparatus, as follows: The liquid to be clarified enters through feed-tube 3 into the bottom portion of tank I and arises in flocculation chamber G. The iirst occules carried along by the liquid to the upper edge of. the upstanding cylindrical portion 9 of the lower tray 9 separate from the liquid. Said cylindrical portion 9' and lower tray 9 discharge the liquid and the fioccules into the lower intermediate compartment 8 wherein additional iloccules separate. The liquid and the separated lioccules pass into the upper intermediate compartment 8 and from the latter into the upper chamber 1 wherein the liquid level is regulated by previous adjustment of cylindrical sleeves 33 of tubes 30 through suitable action by the screws 35. Agitator arms 20-22 are rotated on the surface of the liquid in chamber 1, which sweep the floccules separated in the various compartments and deposited on the surface of the liquid within upper chamber I and lead them toward the bottom inclined radial conduit I5 which carries them to discharge tube I6 through which the sludge separated from the liquid within tank I is withdrawn. The clarified liquid occupying the lowest zone of each compartment 8 and upper chamber 1 by reason of the floccules tending to arise on account of their buoyed up condition, is withdrawn through tubes I I and discharged through vertical tubes 30 within the box 3l and iinally collected through vertical tube 31 in the aforesaid collector tank (not shown).

The tank I, box 3| and clarified liquid collector l tank being sealed, the system operates at a pressure below atmospherical pressure, preferably at a pressure of 35 mms., and a difference of 3 C. in temperature is used below the temperature corresponding to the vacuum pressure in the apparatus in order to avoid treatment of the liquid at a temperature sometimes above 216 F. at which the continuous clarication operation must be performed under the processes and apparatus at present used. My vacuum process and apparatus eliminate the losses of sucrose on inversion which at present occur as caused by heat and the increase of darkness of color of Syrups due to the candied condition attained by sucrose, thereby causing the use of a larger amount'of decoloring agents in the decoloring operation in order to obtain the so-called No. 1 liquor and the production of a greater percentage of molasses in the crystallization operation in which reiined sugar is obtained. f

It is obvious that the operating details of the method, the character of the liquid suspension treated, and the construction details of the apparatus for carrying it out can be varied within certain limits without thereby affecting the essential characterA of the inventionL within the scope of the appended claims.

What I claim is:

1. An apparatus for continuous clarification, comprising a cylindrical tank divided by means of trays of frustro-conical shape sloping from the middle portion to the periphery in an upper chamber for sludge separation, a lower liquid en tering and initial occulation chamber, and a plurality of intermediate compartments for additional clarication upwards, a ieed tube for the liquid to be clarified in the lower chamber, said trays having a large opening at the center or their upper portion from the edge of which rises a cylindrical tube, a sludge discharge tube above the liquid level in the upper chamber means for maintaining reduced pressure in the tank, land tubes for withdrawal of clariiied liquid at a point of the lowest Zone or each compartment.

2. An apparatus for continuous clarification, comprising a cylindrical tank divided by means of circular trays of frustro-ccnical shape sloping from the middle portion to the periphery in an upper sludge separation chamber, a lower chamber for liquid entrance and initial ilocculation and intermediate compartments for additional clarification upwards, a feed tube for the liquid to be clariiied in the lower chamber, said trays having a large 'opening at the center of their upper portion from the edge of which rises a cylindrical tube, agitator arms rotatably mounted on a vertical shaft in the upper chamber at a level adjacent the liquid surface, means for `maintaining reduced pressure in the tank, a radial conduit having an inclined bottom portion situated beneath the agitator arms to receive the sludge gathered on the liquid surface, a sludge discharge tube connected to the tank wall at the end of the radial conduit, and tubes for withdrawing claried liquid at a point of the lowest zone of each compartment.

3. An apparatus for continuous clarification, comprising a cylindrical tank divided by means of circular trays of frusto-conical shape sloping from the middle portion to the periphery in an upper sludge separation chamber, a lower chamber for liquid entrance and initial flocculation and intermediate compartments for additional clarication upwards, said trays having a large opening at the center of their upper portion from the edges of which rises a cylindrical portion which does not reach the immediate upper tray, a feed tube for the liquid to be clarified in the lower chamber, which tube ends in the shape of an inverted syphon at a predetermined height above the tank bottom, agitator arms rotatably mounted on a vertical shaft in the upper charnber at a level adjacent the liquid surface, a radial conduit having an inclined bottom portion situated beneath the agitator arms to receive the sludge gathered on the liquid surface, a sludge discharge tube connected to the tank wall at the end of the radial conduit, tubes for withdrawal of clarified liquid at a point of the lowest zone of each intermediate compartment and upper chamber,l means for maintaining reduced pres- 6 i sure in the tank and outer means for regulating the surface level of the liquid within the tank, said means consisting of a box enclosing the upper portions of the clariiied liquid withdrawal tubes and cylindrical sleeves slidably adjusted on the discharge openings of the withdrawal tubes for regulating the discharge :tall height within the box.

4. Apparatus for continuous operation on liquid suspensions, comprising a sealed casing arrangement for holding an ever-changing body of liquid being treated, annular baie means having an inclined face separating such casing arrangement into liquid communicating compartments, means for applying suction to the interior of the casing for maintaining sub-atmospheric pressure on liquid therein, means for controlling the elevation of the liquid level in the casing, means for withdrawing floating material from such liquid level, means for conducting feed-liquid through the bottom section of the casing to the region of such level, and means including a conduit passing through the casing and leading from an elevation substantially below such level for withdrawing downwardly descending clarified liquid from at least one of the compartments through a liquidconducting passage located functionally remote from such level and adjacent the bottom of that compartment.

5. Apparatus for continuous operation on liquid suspensions, comprising a sealed tank adapted to hold an ever-changing body of liquid being treated, means for applying suction to the inte 1icr of the tank for maintaining sub-atmospheric pressure on liquid therein, means for withdrawing floating material from the liquid level in the tank, means for conducting 4feed-liquid through the bottom section of the tank and risingly to the region of such level, substantially annular baille means extending to an elevation below such level in the tank and so disposed as to encircle the conducted feed-liquid but with one side thereof facing such feed-liquid and with one side thereof facing away from such feed-liquid, and means for passing downwardly descended clarified liquid to discharge from the tank including conduit means passing through the tank as well as leading from an elevation below such level and from that side of the baffle means facing away from such feed-liquid.

6. Apparatus according to claim 5, with the addition of a chamber extending beyond the tank but subject to subatmospheric pressure for holding under such sub-pressure a column of clarified efiluent liquid passed from the tank to the cham ber, said conduit means leading from the tank to the chamber, and means for discharging liquid from the chamber to the atmosphere.

7. Apparatus according to claim 5, with the addition of a chamber extending beyond the tank but subject to such sub-atmospheric pressure for holding under such sub-pressure a column of upflowing clarified effluent liquid passed from the tank to the chamber, said conduit means leading from the tank to the chamber, means for discharging liquid from the chamber to the atmosphere, adjustable means associated with the chamber operative upon the eiiiuent liquid delivered through said conduit means for controlling the liquid level therein, and means extending to a place of atmospheric pressure for adjusting the adjustable means.

JOS RAMN osUNA.