US1860321A - Manufacture of sugar - Google Patents

Description

May 2 4, 1932.

are. RAMSEY ET AL 1,860,321

MANUFACTURE OF SUGAR Original FiledMay af gze Sheets-Sheet 1 ATTORNEYS May 24, 1932. '5 R. RAMSEIYPETAL iaANnFAcTuRE 0F SUGAR ginal Filed May 8, 1926 3 shegtssheet 2 INVENTOR .s/qy

[/mez 19. Ram BYJr/hqr M 80/ ATTORNEY 3 heets-Sheet 3 E. R. RAMSEYFET AL MANUFACTURE OF SUGAR Original Filed May a, .1926

Maiy 24, 1932.

wk g Q? :SQ ma Patented Niay 24, 1932 UNITED STATES PATENT OFFICE EIMER n. RAMSEY, or LARCHMONT, new YORK, AND ARTHUR w. BULL, or NAUGA- rucx, commc'rrcur, assrenons, BY MESNE assrenmznn'rs, 'ro THE Donn com- PANY, INC., on NEW YORK, N. Y., A CORPORATION or DELAWARE MANUFACTURE OF SUGAR Original application filed May 8, 1926, Serial No. 107,579. Divided and this application filed November 12,1930. Serial No. 495,088.

This invention relates to the manufacture of sugar. It is more particularly directed to the automatic control of the treatment process of sugar-bearing juices, such as beet or cane, employed in the manufacture of sugar; although the principles of the invention may also be employed with advantage in other treatment processes.

In treatment processes of numerous kinds,

it has long been desirable to use a conveniently applicable method and apparatus for conducting the treatment operation within definite, prescribed and desired limits which can be automatically controlled. It, is also of ad- .15 vantage that such operations be conducted in a continuous manner, rather than in the more usual batch fashion. Our discovery makes such a practice possible, because by the im proved method and apparatus of this invention we are able to readily conduct the treatment operation under automatically con trolled conditions in such manner that the materials going into the treatment process emerge at the end of their reaction within 2 definitely prescribed limits of content.

Again, it is also highly desirable that such preliminary automatic control of the treatment process be carried out in such manner that the subsequent steps in the treatment 80 process may be more efliciently conducted.

We are able to do this as will be hereinafter more particularly pointed out.

Briefly andtin its broader aspects, our invention comprises a method and apparatus for securing an action responsive to changes in a variable component of the treatment process at a point removed from the zone of active reaction, and utilizing said action to automatically vary the content of said component to predetermined limits.

Our invention will be better understood by reference to its successful use in the manufacture of sugar, particularly in the prelimis nary treatment of sugar-bearing liquids with gases. as in the first carbonation stepof the standard purification process, and then in the subsequent treatment of the carbonated juices whereby a separation is made between the solids and the juices.

Briefly stated, the operations involved in the manufacture of sugar are as follows: (a)

extraction of the juice from-beets or cane; i (b) clarification of the juices; (a) concentra ,7

tion of the juice to sirup; (d) or stallization of the sugar from the sirup; (a; separation of the crystals; and (f) treatment of the.

separated sirup for the working up of the after-products.

Our invention is more particularly directed towards the operation dealing with (b) clarification of the juices. The first operation above referred to, (a) extraction of the juices such as from the beet root, is generall carried on in so-called difi'usion batteries. en the diffusion juice leaves the battery it is cloudy and contains in solution or suspension-- the soluble constituents of the beet, namely,

sucrose, potassium. and sodium salts of phosphoric, sulphuric, hydrochloric, oxalic, and

I tartaric acids, proteins, pectins, etc., and a of lime Ca'(OH) is added to the heated juices; and in the second, known as carbonation, the lime, Ca(OH) is removedby precipitation as CaCOa with carbon dioxide (CO gas.

After liming (defecation), the juice is ready for the second stage of the clarifying operation, namely, carbonation or saturation'with carbon dioxidegas, in which the lime is precipitated. Small amounts of minoral and organic matter are also thrown down. The original slightly acid beet juices become alkaline by the addition of an excess of lime during the liming operation. It is desirable to reduce the alkalinity to certain limits by correct additions of CO in the carbonation step. 4

The carbonated materials are then subloo jected to continuous thickening to separate the clear juice from the sludge. The sludge from the thickening operation is next subjected to continuous filtering, whereby the remaining clear juices are efficiently separated from the undesirable solids.

If the clarifying steps have been well conducted, the resultant clear juices are then in condition for the subsequent operations of sugar making, steps a, d, e, and f, as outlined above. Heretofore accurate anddependable control of the alkalinity of the carbonated juices within predetermined desired limits has been difiicult of attainment. This is even true in the more common practice of treatment of batches of the juices, and is more particularly true in attempted continuous methods of treatment.

The carbonation, injection of carbon dioxide gas, is usually accomplished by highly skilled operators, known as carbonators, who require long preliminary training. The ultimate recovery of sugar and the efliciency of the operation further depend very much on the way in which these skilled operators conduct the process.

The use of our invention permits an accurate and dependable automatic control of a continuous carbonation step, which also materially aids in the subsequent separation of thesolids from the clear sugar juices. Moreover, the dependence on hand control of skilled carbonators is dispensed with.

In our present practice of the invention,

. and lime compounds or solutions are automatically flowed-together into the first of aseries of carbonating vessels. Suitable pumps are employed for this purpose. An excess of lime is employed which throws the slightly acid beet juice over into the alkaline state. A carbon dioxide-bearing gas, preferably under regulated pressure, is injected into the body of limed juices on the counter-current principle. flow downwardly as the injected carbon dioxide as rises upwardly from near the bottom of t e carbonation tanks. The alkalinity is somewhat reduced as the lime precipitates in the form of calcium carbonate.

The preliminary carbonated juices are the led to a secondcarbonat'or for a further treatment with carbon dioxide gas. It may here be pointed out that we have quite satisfactorily employed as many as three ,carbonators in series, as well as only one carbonator. However, we prefer to make use of but two carbonators in series. The foam generated in the first carbonator passes from the top of the first carbonator tothe top of the second carbonator, whereas the carbonated limed juice passes from the bottom of the-first carbonator to the juice level of the second carbonator. A portion of previously carbonated juice,

That is to say, the limed juicescontaining precipitated calcium carbonate,

may be recirculated from the bottom of the second carbonator tank and led into the top of the first carbonator tank. The particles of K calcium carbonate then .tend to encourage particle growth as they pass toward the bot-.

mined limits of alkalinity. This automatically controlled feature which may control the feed of juice instead of thefeed of gas, so long as proportions of the mixture are controlled is made to depend upon the electrical resistance offered by the treated uices,

coming from the last carbonator, between suitable electrodes appropriately immersed in the liquid at a point removed from the zone of active reaction of the carbon dioxide gas on the limed juices. It is important to measure this electrical resistance at a point beyond all further reaction of'the added ingredients, or else the electrical resistance cannot be regarded asa true criterion from which to automatically control the end point. The electrical resistance of the materials is apparently substantially unaffected by the purity, concentration of the sugar juices, or the presence of precipitated solids. On the other hand, the concentration of dissolved lime, which is the measure of alkalinity, appears to be the predominating factor. Hence, the electrical resistance-will vary as the concentration of dissolved lime varies. There is an? ilmost constant parallelism between alkali *ity and electrical conductivity.

"- It' is essentiakthat the electrical resistance be measured after chemical and dissolution reactions have been completed. In the carbonationtanks the reaction of carbon dioxide gas on dissolved lime takes place so rapidly that the concentration of lime in true solutionis reduced below the value it would have if the gas were momentarily cut off and the remainlng undissolved lime were allowed to pass 1nto solution. For this reason we place the electrodes in a-continually flowing stream of juice at some distance from the carbonation tanks so that complete solution of soluble lime will have occurred before the juice reaches the electrode chamber. If the electrodes be placed in the flowing sampling stream of juice where it is exposed to the atmosphere, the uucombined acid gas bubbles entrained in the juice escape therefrom which renders the indication by the electrodes more precisely that of the true alkalinity of the juice.

The permissible limits of alkalinity are 0.07 to 0.13 measured in gramsof CaO per 100 cc. of filtered juice. We have been able to make long continuous runs in which the alkalinity was maintained within the very izo narrow and highly desirable range of 0.09 to 0.11 grams of CaO per 100 cc. of juice.

The control or standard resistance (one resistance arm of a Wheatstone. bridge, as will be more fully explained below) may be set to correspond with an alkalinity of, let us tion of the juices, whereby definitely desired and and predetermined limits of alkalinity are obtained, plays an important part in increasing the particle size and settling rate of the solids.

Our invention will be more fully understood by reference to the accompanying drawings, taken in conjunction with the following description, in which:

-Fig. 1 is an elevational view of the apparatus;'

Fig. 2 is a plan view of the apparatus;'

Fig. 3 is a sectional elevation on an enlarged scale of the temperature regulator and electrode pot;

Fig. 4 is a schematic view of the electrical controller and recorder apparatus and of the electrical relay circuit;

Fig. 5 is a schematic elevational view of the controller in a non-contacting position;

Fig. 6 is a schematic elevatinal view of the controller in a contacting position.

The milk of lime or other limeicompound storage tank 1 rests upon the foundation 2 A feed line 3 leads to the tank 1. A pump 4 connects the tank 1 with the pipe 5, which leads to the T 6.

The sugar juices'torage tank 7 also rests on the foundation 2. A- feed supply line 8 leads to the tank and is equipped with a float valve 9. The float 10 is so adjusted as to close the valve 9 when the tank 7 is filled to a predetermined level. A pump 11 connects the tank 7 with the pipe 12 which leads into the T 6.

The pipe leads from the T 6 to'the top of the first carbonating tank 14. A baflle 15 is located directly under the outlet of pipe 13 and extends to within a relatively short distance of the side of the tank 14, so that a space 16 is provided between the end of the baflle and the side wall of the carbonating tank.

- The bottom of the carbonating tank has a conduit 17 which leads up to the normal liquid level maintained within'the second carbonating tank 18. foam conduit 19leads from the top of the first carbonating tank 14 to the top of the second carbonating tank 18.

The second carbonating tank 18 is equipped I at the top with a foam oiftake pipe 20. A

conduit 21 is located at the bottom of the sec-' ond carbonating tank and connects with a T 22.

A pipe 23 leads from the T 22back to the pump 24 resting upon the foundation 25.

This pump has a connecting pipe 26 leading up to the T 6, and is also provided with offtake pipes 27 and 28 leading into the first carbonating tank 14. The otftake pipe 28 leads into the carbonating tank at a point above the normal liquid level maintained within the tank; 'while the ofi'take pipe 27 leads into the carbonating tank near the lower part thereof.

The first carbonating tank 14 and the second carbonating tank 18 rest upon supports 29. These tanks are also equipped with carbon dioxide gas supplying apparatus. The gas inlet pipe 30 is equipped with an Ofi'take pipe 31 leading to the first carbonating tank,

and an ofi'take pipe 32 leading to the second carbonating tank. A steam pipe 33, with a control valve 34, connects with the oft'take pipe 31. A steam pipe 35 with ,a control valve 36 connects with the offtake pipe 32. The ofl'take pipe 31 branches ofi into the four feed pipes 37 which in turn lead into the first carbonating tank near the .bottom thereof. The portions of the four pipes '37 within the first carbonating tank 14 are perforated so that gas may issue therethrough and pass up through the liquid contents of the tank.

The ofi'take pipe 32 is equipped with three feed pipes 38. which in similar manner to pipes 37 lead into the second carbonating tank 18. The portions of the pipes 38 which extend within the carbonating tank are perforated so that the gas may be permitted to pass up through the liquid contents of. this second carboiiating tank.

The vgfftake pipe 31 has a. manually operable valve 39 which may be turned to regulate the Flow of gas within the first carbonating tank. The otftake pipe 32 is equipped with an automatic control valve 40, having a gear 41, to regulate the flow of gas into the second carbonating tank. This valve is op erated in such manner as to conform with variations in alkalinity of the carbonated juices.

A pipe 42 leads through the heater 43 (which may be heated in any appropriate manner such as by steam, gas or electricity) and connects with the continuous thickener 44. A foam pipe 45 leads from the top level of the pipe 42 to the foam escape pipe 20, attached to the top of the second carbonating tank 18.

A coil pipe 46 (Fig. 3) connects with the pipe 42 and passes through a heating chamber 47 to the electrode pot or sampling bowl 48. The heating chamber 47 has a steam in let pipe 49 equipped with an automatically controllable valve 50. A temperature indisteam valve. An outlet pipe is provided on the heating chamber 47 to conduct away steam. The electrode pct 48 or sampling bowl 48 which is preferably open to the atmosphere is equipped with a disk 54 which fits loosely in the top thereof, which disk in turn contains the \four electrodes 56 and 56'. These electrodes may be made by sealing short pieces of No. 18 Brown and Sharpe gauge platinum wire into the ends of glass tubes. The exposed portions of the wires are approximately 9," long. Two of these electrodes 56 form a pair and are connected to a controller, and the other two electrodes 56 are connected to a resistance recorder. The electrode pot 48 rests within the overflow vessel 57, which has an outlet 58 connecting a pump 59. A pipe 60 connects the pump 59 with the pipe 42 leading to the continuous thickener 44.

' The electrodes 56 and 56 by means of lead wires 61 are connected to the controller, re-

corder, contact disks, relay, and automatic gas valve control apparatus represented by 62,(in Fig. 2) which will be more fully described below in connection with Figs 4, 5 and 6. The continuous thickener 44 is of the tray compartment type. The pipe 42 leads into the feed chamber 63 on the top of the thickener 44. This chamber has a foam ofi'take pipe 64 for the escape of foam. An opening 65 leads from the compartment 63 to the first tray compartment 66. The compartment 66, as well as the second compartment 67 is equipped with a revolving rake apparatus 68, appropriately connected and operated by a shaft 69 and gearing 70, running substantlally parallel to the sloping bottoms 71 of each of the compartments. Boots 72 are provided at the bottom of each of the tray compartments 66 and 67, which seal the bottoms but allow an open space from the top of each boot'to the subjacent compartment beneath, These boots provide effective means for collecting sludge in each individual compartment. The lower compartment 73 also has the revolving raking apparatus 68, but no use is made of a boot. Pipes 74, 75 and 76 lead respectively from near the top of the compartm'ents '66," 67 and.73 to 66 a clear liquid collecting vessel 77. An outletpipe 78 is connected to the bottom of the collectmg vessel 77. The tops .of the pipes I 74, 75 and 76 are provided with adjustable sleeves. (not shown) to control, or balance, the hydrostatic pressure of the escaping supernatant liquid with the hydrostatic pressure maintained within each separate compartment 66, 67' and 73. Outlet pipes 79, 80 and 81 connect respectively with the bottoms of the tray compartments 66, 67 and 7 3. They lead up to the pumps 82, 83 and 84.

The pumps 82, 83 and 84 are in turn connected to the pipe 85 leading through the heater .86 (which may be heated by means of steam, gas or electricity, etc.) to the continuous filter 87.

The continuous filter 87 may be of any standard and appropriate type commonly found on the market. A solids ofl't'ake pipe 88 is provided to remove the separated solids, while the pipe 89 is connected to the filter in order to remove the clear-,juices. This continuous filter may be of the ordinary. revolving kind, in which the filter drum is made to revolve through a trough containing the sludge to be filtered. Suction is provided on the inside of the drum to suck the clear juices from the trough, through the filter cloths, into the filter drum; while the solids adhere to the filter cloth, only to be forced off by a blast of air or scraping action, when the drum has revolved to the desired unloading position.

A clear juice tank 90 is connected with the ofi'take pipe 89 from the continuous filter 87,

and the ofltake pipe 78 from the continuous thickener 44.

All of the apparatus described, through which the juices are made to flow, are carefully insulated so. that the loss of heat by radiation may be reduced to a minimum. It is important that the temperature of the treatment process be brought to and maintained at appropriate levels.

The two pairs of electrodes 56 and 56' and the terminals of the controller, recorder and relays are preferably connected according to Figs. 4, 5, and 6,'in which use is made of the Wheatstone bridge principle.

The pair of electrodes 56, forms one resistance arm of .thecontroller bridge, and the other arms of the bridge are '91, 92 and 93. The bridge employing the pair of electrodes 56'is used in connection with the controller mechanism, which mechanism in turn actuates the relays in' such manner as tooperate the gas control valve 40. A shunted and adjustable resistance 94 is provided adjacent to the electrodes 56 in order to make undue changes in resistance etween the electrodes. A resistance 95 is provided between the transformer 96 and the bridge arms 92 and 93 to regulate the current supplied to the bridge. A rheostat 98 is placed in the galvanometer circuit to regulate the flow of current through the galvanometer windings. A galvanometer field coil 99 is placed in the circuit of the transformer 96, and is protected by the resistance coils 100 placed in series.- A key 101' is placed betweenthe transformer and the bridge in order'to cut-in or cut-out the current, which is taken from the alternating current supply lines 102 and 103. The coil values generally employed are as follows: 91, 92 and 93 equal 200 ohms each; 94 equals 100 ohms; is variable and depends upon the sensitivity of the galvanometer; 98 equals 150 ohms; and equals 4 to 7.5 ohms.

The controller mechanism is preferably enclosed in a cabinet 104. A motor 105, fed from the current supply lines 102 and 103 is connected to the controller mechanism by means of the connecting shaft 106.

The other pair of electrodes 56 is used in conjunction with the recorder mechanism. A similar Wheatstone bridge is employed, with corresponding descriptive numbers 91, 92', 94', 95', 96, 97', 98, 99, 100' and 101', as used in describing the controller Wheatstone bridge. I

The controller mechanism 104 is in turn connected with contact disks 107 and 108. These contact disks are operatively connected to the main shaft 109 of the motor 110. The

motor 110 gets its energy from the main current supply lines 102 and 103. The disks may be appropriately geared to the main shaft of the motor in such manner as to reduce or increase the speed of the,same, as compared with the normal speed of the motor. The disks 107 and 108 have a contact segment 111 and 112, respectively, at the outer rim, which contact with the brushes 113 and 114 as the disks revolve. The remainder of the disks are insulated to prevent straying of the current. An appropriate current conducting wire 115 connects se ent member 111 with the segment mem er 112. A current conductor 116 connects the main supply line 103 with the brush 113, which brush contacts with the segment member 111. A current conducting wire 117 connects the controller mechanism 104 with the brush 114, which brush contacts the segment member 112.

A relay mechanism is appropriately con nected with the controller mechanism, as well as with the main current supply lines, and the gas control motor. A current conducting line 118 connects one terminal of the controller mechanism with the relay solenoid 119. A spring 120 is connected to one end of the solenoid member to keep it in a constant position when the solenoid windings 121 are not energized.

. A current conducting line 122 connects another terminal of the controller mechanism 104 with the relay solenoid member 123. A

1 spring 124 is connected to one end of the solenoid member 123 to keep it in a constant position when the solenoid windings 125 are not energized. Y

The solenoid member 119 is equipped with two pivoting contact brushes 126 and 127 while the solenoid member 123 is e uipped with two'similar pivoting contact rushes 128 and 129. The brush 126 is so positioned as to brush across the contacts 130 and 131; while brush 127 is so positioned as to brush across the contacts 132 and 133. The brush 128 is so positioned as to brush across the contacts 134 and 135;while brush 129 is so positioned as to brush across the contacts 136 and 137.

The gas control valve motor 138 is prois adapted to operate the motor in either direction depending in which direction the field coil is energized. This winding connects with the contacts 130 and 133 of the solenoid 119; and with the contacts 134 and 137 of the solenoid 123. One terminal of the motor is connected with the main current supply line 102, while the other terminal is connected to the current conductin line running between the contacts 131 an 135.

The current conducting line 118, which vvided with a motor field winding 139, which as with the main current supply line 103. A

current conducting line connects the pivoting contact brush 127 with the pivoting con- 3 tact brush 129, as .well as with the main current supply line 102.

The gas control valve motor 138 has a main shaft 140 geared at the far end 141 to mesh the gear member 41, which gear member in turn is operatively connected to the gas control valve 40. The shaft 140 is provided with a friction disk 142 operatively connect ed to the brake 143 pivoted at the point 144. A spring 145 is adapted to pull the friction brake down upon the friction disk 142. A brake solenoid 146 is attached to the free end of the brake in such manner that when the solenoid is energized, the brake may be lifted freely above the friction disk 142 about the pivotal point 144. r gized by means of the current conducting line 147, connected to terminals of the motor 138, and forming the solenoid windmg c011 about the solenoid member 146.

Figs. 5 and 6 are schematic views of the controller mechanism within the cabinet 104. The motor 105 drives the shaft 106 upon The solenoid is ener-.

which are placed the cams 157 and 157'.

These cams are conductors of electricity, but

are insulated around the shaft 106 'so that,

alvanometer needle 97 is so positioned that it fluctuates to the right or left, depending upon how the resistance between the pair of electrodes 56 varies in the Wheatstone bridge above referred to. The controller mechanism is made to rest and hinge upon the frame work 158. A rocking frame 159 is pivotally connected to the frame 158, at the points 160. A rocking frame arm 161 is attached tothe rocking frame 159 and it depends to within contacting distance of the eccentric cam 162 located on the motor shaft 106. This eccentric 'cam is so positioned on the shaft as to make the rocking frame 159 rise and fall as the shaft 106 is rotated. The lugs 167 provide means for stopping the needle in the extreme right or left position. The lever arms 168 and 169 are freely pivoted at the points 164 and 165. 'These lever arms have extension arms 17 O and 171 which extend almost halfway across the area circumscribed by the moving galvanometer needle 97. A suflicient space between the lever arm extensions 170 and 171 is provided so that the galvanometer needle may freely rest between them when the Wheatstone bridge is in the balanced position. The lever arms are so designed that when the galvanometer needle is deflected to either the right or left, the

rocking frame 159, on any of its upward movements, may lightly press the galvanometer needle against the lever arm ex- I tensions 170 or 171 and thus corresponding- 1y move the extreme lower ends of the lever arms 168 or 169 inwardly.

A balancing arm 172 is pivoted to the memher 163 and the main frame 158 at the point brush across the current conducting cams 157 rent conducting wires 118 and 122,-which 35 and regulated by the valve 36. The mixl and 157 when the balancing arm is inits normally horizontal;- and balanced position. These In S are currentjconductors and are insulated rom the balancing member 172 by means of thenon-conducting material 175 placed between the lugs and the balancing member. These lugs are in turn connected to ,the current conducting wire 117, which wire is attached to the brush 114 at disk 108.

A freely movable frame 176, with lugs 177 and 178, is freely pivoted at the point 166, in working position with the lever arms 168 and 169. This frame formsa rigid part of the balancing arm 172, so that when, the lugs 178 or 177 are pressed by the lever arms 169 or 168 respectively, the balance arm 172 will be relatively moved in its clockwise, or anticlockwise, position.

Contact brushes 179 and 180 are so positioned as to make contact with .the current conducting cams 157 and 157 as the cams revolve with and about the motor shaft 106. The brushes are also connedted to the curlead to the relay mechanism above described.

The recorder mechanism 181 is of a standard type used for ordinary recording purposes of this kind. It is operated by means of the shaft 182 connected to-the motor 183. This recorder motor is fed by current from the main current suppl lines 102 and 103.

The operation is as ollowsz' Milk of lime or other lime compound from storage tank 1, and raw diffusion sugar juices from the storage tank 7, both of which have been preliminarily heated, are conducted by means of pumps 4 and 11 to join each other in the T 6. The intermingled milk of lime and beet or cane juices thereupon flow together through pipe 13 onto the baffle 15. This baffle 15 is so positioned within the first carbonator tank 14 that the combined juices may trickle down the side wall of the carbonator tank through the space 16, between the carbonator wall and the bafiie itself. This is done in order to cause as little agitation of the juices as possible, thus preventing any undue formation of foam.

As the carbonator tank 14 gradually fills up with the combined milk of lime and beet uices, a part of the mixture is forced by way of the pipe 17 from the bottom of the first carbonator tank 14 into the second carbonator tank 18. The inlet level of the pipe 17 in the second carbonator tank is at the normal liquid level of the two carbonator tanks. j Any foam that is formed within the first carbonator tank 14 is permitted to pass over to the second carbonator tank 18 by way of pipe 19. A part of this foam will disintegrate into juices within the second carbonator tank, and whatever foam is not precipitated is permitted to pass up through the foam outlet pipe 20..

A gas containing carbon dioxide is fed through the supply pipe 30 and branches off to the first and to the second carbonator tanks. The carbon dioxide gas passing to the first carbonator tank 14 by way of pipe 31 is brought to a desired temperature by means of steam supplied through pipe 33 and controlled by valve 34. The mixture of carbon dioxide gas and steam are thereupon subdivided into four main divisions by means of pipes 37. The gas is then permitted to escape through the perforations within the parts of the pipes 37 extending into the first carbonator tank. The gas bubbles up through the body of juices. The chemical reaction, Ca (OH) 2 CO CaCO +H O takes place. Any excess gas escapes with the ture of carbon dioxide gas and steam is conducted to ether for a short distance, and it is then su -divided into three main streams in those portions of the pipes 38 extending within the carbonating tank. Any excess gas escaping from the body of juices is permitted to escape with the foam up the stack-20.

The amount of gas admitted to the second carbonator tank is automatically controlled within predetermined limits by means ofthe valve 40, which will be more fully explained below.

If the juices within the second carbonator tank have not been given a suflicient amount of gas, or'in fact have been given toomuch gas, the juices may be recirculated by way of pipe 23 and pump 24 back into the first carbonator tank. Valves and piping are so arranged that the recirculated juices may-be Y admitted near the bottom of thefirst carbonator tank by way of pipe 27, or above the .normal liquid level of the first carbonator tank by means of pipe 28. Or, if simultaneous mixing of lime, raw juice and carbonated 'uice is desired, the valves 27 and 28 can be' ept closed whereupon the recirculating julce will pass to the T 6 and through pipe 13 to the first carbonator.

Since it is ad'vantageousto increase the particle size of the calcium carbonate, CaCO in order. to make the subsequent steps of thickening and filtering more efficient, large portions of the gassed contents of the second carbonatortankare recirculated back to the first carbonator. We have found it advantageous to recirculate about six volumes from the second carbonator tank, to the first carbonator tank, to one volume of fresh combined beet juices and milk of lime initially introduced into the first carbonator tank. The particles of CaCO, which are transferred from the second carbonator tank to the first carbonator tank induce particle growth. That is to say, freshly precipitated (121002 in the first carbonator tank adheres to andbecomes part of particles of CaCO circulated, from the second carbonator tank back to the first carbonator tank. This relarger volume of alkaline carbonated juice be 5 wide variations in alkalinity.

present, it tends to dampen and restrict the reach the continuous thickener.

from a later tank portion then passes into the electrode pot 48 where the electrical resistance between the pairs of electrodes 56 and 56 are appropriately measured. Since the electrical resistance between these electrodes is inversely proportionate to the alkalinity of the test portion, use may be made of this relationship to automatically control the amount of CO gas admitted to the second carbonator tank by way of the automatic gas valve 40. The test portion. which continuously flows into the electrode pot 48 gradually overflows the same into the collecting chamber 57. The pump 59 continuously passes the overflowing test portion back into the line 42 by way of pipe 60.

It is very important that the test portionbe taken at a point well removed from the zone of chemical and dissolution reactions within the carbonating tanks; The reaction that takes place within the last carbonator tank between the CO and the Ca( OH) 2 is so rapid that the concentration of Ca(OH) 2 in true solution is reduced below the value it would have if the gaswere momentarily cut oif and the remaining undissolved'Ca(OH) were allowed to pass into solution. If the test portion is taken well removed from the zone of active reaction, complete solution of the soluble Ca(OI-I) will have occurred before the juices reach the electrode pot.

The previously heated bodies of juices have cooled down somewhat by the time they For that reason the heater 43 is interposed between the second carbonator tank and the continuous thickener, so that the temperature of the combined juices and solids may be raised to j the temperature found consistent with efficient and rapid thickening. Of course the use of this heater is optional, particularly if the previously gassed liquids have not appreciably fallen in temperature. Any foam which may have found its way into pipe 42 or formed within the pipe 42 is allowed to escape by way of pipe 45 into the foam outlet stack 20.

The combined juices and solids are flowed into the receiving chamber 63 of the continuous thickener 44. These find their way down throughthe outlet 65 of the first tray compartment 66. As this compartment gradually fills up, part of its contents pass to tray compartment 67, and ultimately to tray compartm ent 73. The rakes 68 are set in motion by the shaft 69, to which they are attached, whlchvismade to revolve by a motor (not shown). As the solids settle to the bottom of the sloping tray compartment, the rakes 68 gradually carry the solids toward the center of the compartment, whereupon the solids are continuously withdrawn through the pipes 79, and 81 by means of the pumps 82, 83 and 84:, respectively.

The clear juices, on the other hand, are withdrawn from near the top of the individual tray compartments by means of the pipes 74, 75 and 76 into the collecting chamber 77. The clear juice is then permitted to flow by way 0 outlet 78 into the clear juice collecting tank 90 to await further process treatment used in the manufacture of sugar, such as outlined above.

The sludge which has been pumped from the continuous thickener by means of the pumps 82, 83 and 84 is flowed into the pipe 88 which passes through the heater 86. Since appropriately heated materials will more easily lend themselves to filtering, We have found it advisable to preheat the sludge before it enters the filterer, particularly if there is a substantial drop of temperature during the thickening operation. The use of this heater is optional.

The preheated sludge is th-en'passed into the continuous filter 87, where the remaining clear juices are finally separated from the solids. The solids escape by way of outlet pipe 88, while the clear juices are conducted through the outlet pipe 89 to the clear juice collecting tank 90 to await further process treatment."

The beet juice clarification treatment operation of the invention has just been described, and it now becomes Lnecessary to explain the operation of the automatic control features of our discovery, which are graphically illustrated in Figs. 3, 4, 5 and 6.

Variations in the resistance of the test portion between the electrodes 56, by means of the well known Wheatstone bridge principle, are registered by variations in the swing of thegalvanometer needle 97. For example, if the bridge is perfectly balanced (i. e. when the resistance arms 91, 92 and 93 and the resistance between the electrodes 56 are all equal to one another), the galvanometer coil will not be energized and the needle 97 will consequently not be deflected. If the resistancebetween the electrodes becomes greater than that of its corresponding resistance arm, cur-. rent will be forced through the galvanometer coil in one direction and the needle willibe deflected, let us say, to the left. If the resistance between the electrodes becomes less than that of its corresponding resistance arm, current will be forced through the galvanometer coil'in the opposite direction and the needle will. be deflected to the right The swing of this galvanometer needle is appropriately employed to make corresponding 7 changes in the amounts of CO admitted into also makes the cams 157 and 157' revolve continuously. These revolutions take place at intervals of approximately 6 seconds each. For each revolution the eccentric cam 162 strikes the rocking frame member 161 which in turn forces the rocking frame 159 up against the bottom of the galvanometer needle. This movement of the rocking frame pushes the top of the galvanometer needle against the bottom of the lever arm extension 170, whereupon the lever arm 168, which is pivoted at point 164 bears over to the right and strikes against the lug 177. Since this lug and its frame 176 are rigidly attached to the balance arm 172, the balance arm is swung away from its normally horizontal position; and the contact lug 173 is forced downward, while the opposite contact lug.174 is swung upward. The eccentric cam 162 very soon releases the rocking frame 159, and the galvanometer needle is at once free to move in' any direction in response to any new As the cams 157 and157 are revolved, cam

It is quite apparent that if the galvanometer needle 97 is swung in the righthand direction, that the operation of the mechanism shown in Figs. 5 and 6 will be reversed; and

that the cam 157 will this time brush against the contact lug 17 3, whereupon current may pass through the current conducting line 117, the contact lug 173, the current conducting cam 157, the brush 179, and the current conducting line, 118.

Suppose, on the other hand, that the Wheatstone bridge does not become unbalanced,'due to the exact conditions of alkalinity maintained in the test portion, the galvanometer needle 97 will not deflect either to the right or to the left. The eccentric cam 162 will nevertheless force the rocking frame up against the galvanometer needle; but, since a space is provided between the lever arm extensions 170 and 171 sufliciently large to allow for the free up and down movement of the galvanometer needle, it is apparent that the lever arms 168 and 169 will not be moved; and, consequently, that the balance arm 172 willtherefore continue in its normally hori- .zontal position." When this takes place,

neither the cam 157 nor the cam157' will brush against the contact lugs, and there will therefore be no conductor provided for carrying the alternating current from the current supply line 117 to the current supply line 122, or back again.

Every time the cams 157 and 157 are revolved and make contact with the contact lugs 173.01 174, the automatic gas control valve 40 would normally be correspondinglyopened or closed to control the amount of CO gas admitted into the second carbonator tank. Such frequent changes (once every 6 seconds) in the amount of CO gas admitted to the second carbonator tank would obviously be inadvisable, because after such a change has been made a considerable time elapses before the alkalinity of the juices coming from the second carbonator tank shows a change corresponding to the change in the amount of gas admitted. F or this reason, it is desired to turn the valve 40 less frequently, and it has been found that about 100 seconds should be allowed between changes of the gas valve to make: sure that the full effect of one change has been obtained before another one is made In order to utilize the 6 seconds interval action of the controller mechanism just described, but at the same time to modify its ultimate efl'ect on the control valve 40, provision has been made to make the valve changes at 100' second intervals by means of the contact disks 107 and 108 in cooperation with movements of the controller mecha-L nism. The motor 110 is fed from the main current supply lines 102 and 103. An appropriate gearing, not shown, may be used in conjunction with the driving shaft 109 to slow or speed up the disks 107 and 108. These disks have contact segments 111 and 112, which can be so positioned relatively to one another as to lengthen or retard the time of simultaneous contact with the brushes 113 and 114. The alternating current passing through the contact disks is taken directly from the main current supply line 103, and through the current supply line 117 which is intimately associated with the controller mechanism just described above, as well as the relay system now to be described. Although the controller mechanism revolves once every 6 seconds, there can be no passage of current through the cams 157 and 157' until the brushes 113 and 114 brush against the contact segments 111 and 112 during the interval that these brushes are simultaneously pressing against theircorresponding con tact segments, and the current passes through the current conducting line 115 connecting the two contact segments.

Let us again assume that the galvanometer needle 97 has been deflected to the left (as shown in Fig. 5) the cam 157' will then brush against the raised contact lug 174 and thus form a conductor between the current conducting lines 117 and 122. If at the time the cam 157 brushes against the lug 174, the

brushes 113 and 114 simultaneously bear against the contact segments 111 and 112 of the contact disks 107 and 108, current will pass from the main current supply line 103 through 116, through brush 113, segment 111, 7

102 (through the contact disks, the controller mechanism, and the relay mechanism) and the other main current supply line 103, or vice versa.

Assuming that the galvanometer needle 97 v has been deflected to the right, that is in the opposite direction, it will be apparent that cam 157 will then brush against the now raised contact lug 173. If at the same time the brushes 113 and 114 are simultaneously bearing against the contact segments 111 and 112 of the contact disks 107 and 108, current will again alternate between the current supply lines 103 and 102 asjust described. In

thissituation, however, the current supply line 118 will be substituted for the current conducting line 122. In other words, a complete circuit will then be provided between the main current supply line 103, hne 116,

brush 113, contact segment 111, line 115, contact segment 112, brush 114, line 117, contact lug 17 3, cam 157, brush 179, and the line 118 which winds its way through the relay 'mechanism, back to the main supply line 102,

or vice versa. It is thus again seen that a complete current conducting line has been provided between the mam current supply line 102 (through the contact disks, the controller mechanism, and the relay mechanism) and the other main current supply line 103, or vice versa.

lay mechanism, let us again suppose that the galvanometer. needle 97 has been deflected to the left, (as shown in Fig. 5) and that the controller mechanism and the contact disks- 12 In order to follow the operation of the repulled to the left. The current passes to the pivoted brush 127 at the contact lug132, and

passes from thence back to the main current suppl line 102. As the solenoid core 123 is pulled to the left, the pivoted contact brush 129 is swung over to the contact lug 137, which then provides a current conductor from the main current supply line 102, through contact 137, through the field winding 139 of the gas valve control motor 138. The current continues from the field winding of the motor up to the contact lug 130, through the pivoted brush 126, and fromthence backto theother main current supply line 103.. Since the motor windings are energized by connecting one terminal of the motor with the main current supply line 102 and the other motor terminal-.with the rela circuit connecting the lugs 131 and 135 which latter lineis dead when the solenoids are in their normal position; that is, when they are not energized), the energizing of the motor field winding 139 will make the motor revolve in one direction, with consequent turning of the gas valve in a corresponding direction.

If we now assume that the galvanometer needle has been deflected to the right, and the cam 157 contacts with the now raised lug 173, as the brushes 113 and 114 simultaneously bear against the contact segments 111 and 112 of the contact disks 107 and 108, current will pass down through the line 118 to the solenoid coil 121 of the solenoid 119. The current passes through the solenoid coil 121 to the contact lug 136, through the pivoted brush 129, and from thence back to the main current supply line 102. During the passage of the current through this circuit, the solenoid member 119 is energized in such manner as to draw the solenoid to the right. When this takesplace the pivoted brush 127 swings over to the contact In 133. As soon as this takes place, current asijsgs from the main tion of the gas control valve 40.

In order that the operation of the gas control valve may be quickly stopped 'as soon as the relay circuit solenolds have gone back to their normalposition, provision is made for quickly stopping the motor, instead of letting it gradually die down, as; it normally would. T e motor shaft 140 is provided with a friction disk 142, over and u on which an ppropriate brake 143 is pla As soon as c rrent has passed through the'terminal of the motor, the brake solenoid coil 147 is en ergized and the solenoid member 146 is pulled upwardly. This u ward movement of the solenoid lifts the bra e freely above the friction disk 142, and there is no brake action. The motor may then freeely rotate. As soon as the relay circuit solenoids have been brought back to-their normal position, by

means of the springs 120 or 124, the current no longer flows through the motor terminals the differences in alkalinity from the set 0 standard, b means of a Wheatstone bridge. This recor ing may been the usual graph paper placed upon a revolving cylinder, upon w ich an inked pen traces the curves represented by corresponding variations in resistance,

It is thus seen that in the practice of our invention we are able to continuously treat sugar juices in the manufacture of sugar under automatically controllable conditions.

This represents a step far in advance over the usual batch methods of treatin such sugar containing juices now general y employed in the making of sugar.

The alkalinity of the carbonated juices is 1m not only continuously and automatically controlled within desired andpredetermined limits, but the completely carbonated juices are likewise subjected to continuousseparation of the clear juices from the undesirable solids.

Moreover, we are able to increase the particle size of the solids, over the size obtainable by batch methods, and thus increase the settling and filtering rate of the solids. The density to which the solids will settle represents an increase of about over that obtained under batch operations. We have also found that we can continuously filter our continuously treated juices about 20% faster than under the old batch system heretofore employed.

We claim:

- 1. A-method of carbonating sugar juice which includes the step of continuously mixing lime and juice in the presence of carbonated juice.

2. A method of carbonating sugar juice which includes the step of continuously and substantially simultaneously mixing lime, raw juice and carbonated juice. K

A method of carbonating sugar juice which includes the step of continuously mixing alime compound, raw juice, andeountercurrently with carbon dioxide gas with the -,f

'dioxide gas in the presence of carbonated juice.

5. A method of carbonatingsugar juice which includes the steps of continuously incompletely carbonating with a c untercurrent flow of gas, a mixture of lime and juice in a carbonation zone, and then directly completing carbonation thereof in another carbonation zone. 7

6. A method of carbonating sugar juice which includes the steps of incompletely carbonating with a countercurrent-flow of as, a mixture of lime and juice in a first car onation zone, completing carbonation thereof in another carbonation zone, and then recirculating completely carbonated juice to the first carbonation zone.

.7. A method of carbonating sugar juice comprising continuously incompletely carbonating with gas a mixture of lime and juice in a first carbonation zone, completing carbonation thereof in another carbonation zone, and then recirculating completely carbonated juice to the first carbonation zone, the volume of recirculated juice being more than twice the volume of the liine and juice entering the first carbonation zone.

8. A method of carbonating sugar juice which includes the steps of mixing lime, juice, and gas to bring about carbonation thereof in a carbonation zone, and stimulating particle owth in said zone by cit-- culating theret rough carbonated sugar uice.

9. A method of carbonating sugar juice which includes the step of continuously mi'xing lime, raw juice and carbonated juice within the confines of a single container.

In testimony whereof we aflix our signa tures.

ELMER R; RAMSEY. ARTHUR W. BULL.

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