US2371615A - Hydraulic sizer for suspended solids - Google Patents

Description

March 20,1945. E. A. HAAGENSEN 2,37 5

HYDRAULIQ SIZER FOR SUSPENDED soups Q Filed Sept 10, 1943 7 Sheets-Sheet 1 EDWARD A. HAAGENS'EINA ATTORNEY March 0, A. HAAGENSENQ. 2,371,615

I 7 HYDRAULIC SIZER FOR SUSPENDED SOLIDS Filed Sept: 10, 1943. 7 Sheets-Sheet 2 v V mmvrozc EDWARD A Huesuseu,

ATTORNEY Maich 20, 1,945. E. A. HAAGEiNSEN I 3 1, HYDRAULIC SIZER FOR SUSPENDED SOLIDS Filed Sept. 10, 1943 i 7 Sheeis-Sheeg 3 33 INVENTOILV 7 w 1 hi mh In Q w imuuu "5, i 49 a v.7 I i 49 ESJIM 1; in 1 F IG.3. G 1 A ATTORNEY EDWARD A. HAAGENSEN,

March 20, 1945.

E. A. HAAGENSEN HYDRAULIC SIZER FOR susrnmmn SOLIDS Filed s t. 10, 1943 7 Sheets-Sheet 4 ATTORNEY Ma 1945- E. A. HAAGENSEN 2,371,615 HYDRAULIC SIZER FOR SUSPENDED SOLIDS I Filed Sept. 10, 1943 v Sheets-Shed s INVENTOR.

EDWARD A. HAAGEN'SEN,

ATTORNEY March 20, 1945. E. A. HAAGENSEN ,6

HYDRAULIC SIZER'FOR SUSPENDED SOLIDS Filed Sept. 10', 1943 7 Sheets-Sheet 7 INVENTOR.

EDWARD A. HAAGENSEN,

ATTORNEY S I Patented Ma 20, 1945 2,371,615 nrmmmc SIZER FOR susrnnnnn soLms Edward A. Haagensen, Westport, (lonm, assignor to The Dorr Company, New York, N. Y., a cor- I poration of Delaware Application September 10, 1943, Serial No. 501,841

ll Claims.

This invention relates to hydraulic classifiers or sizers of the hindered settling type wherein solids suspended in liquid are supplied to the sizer and the suspended solids are classified according to particle size so that one fraction issues from the sizer containing larger suspended solids or'sands while another fraction issues called fines.-

The fractionation or size separation takes place in a bath of liquid to which is fed the suspension 'to be classified, The bath of liquid with its suspended solids is maintained in teeter, namely, thoroughly mobilized or in motion. This type of hydraulicclassification is often referred to as hindered settling. The size separating conditions exhibited 'by the teetered' bath or bed of submerged suspended solids are subject to automatic control. This invention is directed to a type of such control.

In a sizerof this type, the suspended solids such as pulps or slurries, are continually fed to a pool or bath of suspended solidsmaintained in a pocket having a construction plate in its bottom section through which liquid under. hydraulic pressure or head is supplied in an upfrom.the sizer containing smaller sized solids,

water, the balancing column of clean water rises to an elevation higher than that of the surfaceof the bath, and the difference in height between the liquid level of the bath and liquid level of the clean water in the column. is called superelevation. This super-elevation is an important factor in determining the proper density of the I bath. Thus any change'in density of the bath containing the mobilized suspended solids that are in teeter and are in the process of being classifled as' to size, is indicated by 9. corresponding change in the liquid level of the clean liquid column thatiis balanced by the denser bath.

The bath and thecolumn stay in equilibrium and therefore fiuctuatetogether, but the liquid column fluctuates much more than does thebath.

Heretofore it has been customary. to associate a diaphragm'with the teeter bath to indicate variations in the density thereof so that the diaphragm would move in one direction-if the density of the bath became too great, and

thus would open the valve plug to let outsome ward'direction to the bath. This hydraulic liquid is usually water but maybe liquidssofgreater density,- including. solutions of salt,

calcium chloride and so on. The head under which the hydraulic water is supplied eifects the teeter or the mobilizing of the suspended solids,

' of the bath, whichis an important, condition ofoperation. The density of the-bath, however,

- eflects the size separating qualities of the ma-- chine, so the automatic control of this invention operates to control the density of the sblids classifying, or sizing bath.

A pocket of such a sizer has a valve plug in its bottom section usually passing through a construction plate for controlling the .rate of 1 sands discharging therethrough, so this inven- 'of theJarg'er solids or sands from the bath, and thus lessen-the density of the bath. Conversely, if the density of the bath was too light,

the diaphragm would move the other way, the valve plug would close and remain closed until the continuing feed of suspended solids to the) bath would raise the density and thus open the valve plug to go on with'normal operation.

October 4, 1926.

tion is directed to automatic operation of, that valve or valve plug, to close or to open'itfor' controlling the density of the bath to be more or less, as thecase may be.

Each pocket containing such a bath .of s uspended solids whose density is important to control, has associated with it (usually ina standpipe) a balancing column of similar liquid, but

That is,.-

substantially free of suspendedsolids. if the bath is made up of water and solids to be classified, the balancing column comprises clean 'water. ,Sincethe bath contains suspended solids and therefore has a greater density than clean The principle of the size classifying operation of a'machine of this type, known to the trade as the Fahrenwald sizer, is well shown and de- Patent 268,663, filing date scribed in British One object of this invention very sensitive but dependable control means motivated by change in superelevation of the balancing column'of clean liquid'to' control a valve plug for varying the density of the teeter bath.-

Another object .a'phragm operated by the'change of level of the balancing column of clear, liq'uid'an impulse from an outside source such as electricity, -whereby. "minutefluctuations' in liquid level of the clean liquid may be multiplied or amplified so that the relativepositioning of the valve plug inthe teeter bath may be controlled correspondingly.

Another objectistorender less bulky, lighter I in weight. more readily mountable and accessible is to provide a of this inventionis to inject into the control means between the floator dlcompany.

. tor armature and the the automatic control means for-the sands discharge valve, and the valve itself.

of the balancing column of clean, liquid (caused correspondingly by change of density of the teeter bath or bed) as a primary impulse for actuating a secondary or relay impulse, extraneous reversible power means or prime mover which opens or closes the sands discharge valve inaccordance with or substantially in unison with, the extent of the primary impulse.

More specifically, these impulses operate in a manner whereby the power means are started or energized to move the valve 'in one direction, and stopped or -de-energized to end that movement. Similarly, the ower means are started in the reverse direction and then stopped if the primary impulse calls for such .opposite control I effect. The extent of the respective opening or closing movements are substantially in proportionto the extent of the corresponding primary or hydraulic impulses.

The invention possesses other objects and features of advantage, some of which with the foregoingwill be set forth in the following description. In the following description andin the claims, parts will be identified by specific names for convenience, but they are intended to be as generic in their application to similar parts as the artwill permit. In the accompanying drawings there has been illustrated the best embodiment of the invention known to me, but such embodiment is to be regarded as typicalonly of many possible embodiments, and the invention is not to be limited thereto.

' The novel features considered characteristic of my invention are set forth with particularity in the appended claims. The invention itself, howdraulic impulse because of the respective proportionate settings effected on both the potentiometers.

Fig. 1 is a side view of a, hindered settling multiple pocket classifier with part of the tank wall broken away to expose in one pocket the'arrangement of the novel sands discharge valve and actuating means, the tank for the purpose of Fig. 4 is an enlarged detail view of the elements operatively connecting the motor shaft with the valve stem, in extreme end operating positions.

Fig. dis a view in the direction 5-5 upon Fig. 4.

Fig. 6 is a view of the actuating elements shown in Fig. 4, further completed by the showing of the sands discharge valve connected therewith.

Fig. 7 is an enlarged detail showing of the devices for automatically actuating the sands discharge valve, to effect automatic density control. r

Fig. 8 shows a detached sub-assembly including the arrangement of the sands discharge valve and of the electrical control means therefor, as well, as the arrangement of an associated clear water pipe for transmitting the primary or hydraulic impulse to the electrical control means.

ever, both as to its organization and its method of operation, together with additional objects an? advantages thereof, will best be understood from the following description of a specific embodimentwhen read in connection with the accompanying drawings in which according to one feature, the extent of the rimary and hydraulic impulse is elebtrically translated into a. proportional amountof rotation of the armature of a motor, which in turn moves the valve..

According to another feature, the means for electrically translating the extent of primary or hydraulic impulse into a proportional extent of valve movement, comprises the Modutrol motor of the Minneapolis-Honeywell Regulator Company, as shown and described in their bulletin'fForm No. 95-1057A entitled Type M904E Modutrol motor, in conjunction with a control circuit as shown and described in the Bulletin entitied Series control circuit" by thesame hydraulic or primary impulse in one direction causes a proportionate change in the setting of a first or controlled potentiometer which therefore energizes a double-throw solenoid actuated switch to start the valve actuating Hence, the

motor. The motor rotates until it has changed Fig. 9 is a, key diagram of a plan view of the classifier tank complete, to identify those portions of the tank that are shown in Figs. 1 and 2 as well as those omitted therein.

Fig. 10 is a key diagram of the classifier tank representing the side view.

Figs. 11, 12, 13 and 14 are wiring diagrams illustrating the operating cycle of the electrical control means which actuate the sands discharge valve for effecting automatic density control.

The hindered settling type of hydraulic classifier herein shown to illustrate the invention comprises a tank 10 resembling adeep trough having a narrow feed inlet end II and a wider liquid 'outlet or overfiow end l2. That is to say,

the tank l0 comprises side walls l3 and It diverging from the inlet towards the overflow end, a horizontal bottom It, a narrow end wall 16, and a wide end wall I1.

The tank is subdivided into a series of pockets I by transverse submerged partitions such as represented for instance by partitions l8 (Fig. 1). The actual disposition of the pockets is indicated in the key diagrams of Figs. 9 and 10 showing the setting of a second or motor balancing potentiometer sumciently to'restore the switch to its neutral or normal electrically balanced condition wherebyit stops the motor. impulse in' the opposite direction will produce an amount of rotation of the motor in reverse. The amount of rotational movement of the m0- corresponding extent of the valve-setting movement are substantially. proportionate to the extent of the primary or by- A primaryeight pockets 2| to 28. equipped with the novel automatic-sands discharge and density control devices. The key' diagram (Figs; 9 and 10) indicates parts A, B and C of the tank as being those which are shown in Figs. 1 and 2, while indicating at D and E the parts that have been omitted or broken away in Figs. land 2.

A pocket 20 closest. to the narrow inlet end of the tank diflfersfrom the others in that it lacks the control devices.

Each of the-pockets 2| to 28 has a perforated false bottom or perforated flow constriction plate 29, forming between it and the tank bottom it discharging the carrying liquid fro the tank and ends.

a pressure chamber 20 to receive liquid under hydraulic pressure herein also called teeter liquid for the purpose to-be further explained. The

ith

constriction plate 29 also defines the floor of a" I classifying pocket in which during operation there is established a hindered settling classifying zone or pool that comprises a bath or teeter bed approximately of a depth T,. as hydraulic liquid from the press'urechamber 30 is forced upwardly through theconstriction plate whereby the sands in the slurry passing through the tank are graded in a manner further to be described.

. Each .of the pockets 2| to 28 also has a sands discharge valve 2! comprising a valve seat 22, a sands outlet passage 23 leadingfrom the valve seat through the pressure chamber 20 and through the tank bottom I out of the tank to a discharge, and/a valve body 34 provided with a valve stem 25.

The pocket is relatively shallow'as comextends to a point well above the top edge of the partitions l8, and over which the feed suspension enters the first or valve-less classifying pocket 20.

I The sands-carrying liquid feed passes from the pocket 20 in a continually widening stream over the pockets 2| to 28, the depth of this stream above the top edge of the partitions l8 being determined by the height of overfl means for which various sizes of sand particles have been removed by the classifying action of the pockets 2i .to 22,

and which overflow means will be presently deprise an overflow receiving trough or launder 4| at each side of the tank and are shown to extend along that section of the tank that is occupiedby all but the pockets 20, Hand 22. These overflowlaunders are shown to have a sloping bottom 42 and an outlet 43 at the extreme wide end ofthe tank. Consequently, that section of the tank that corresponds to the pockets 23 150 2 8 is provided with adjustable overflow weir members 44, one at each side of each pocket (see Figs.- 1 and 2). The last or-widest classifying pocket 24 has an additional overflow weir member 45- adjustably mounted upon the end wall I! of the tank. This last mentioned weir member allows overflow liquid to be discharged-intoa transverse trough or. launder I9 extending between exten-.

sions l3 and I 4"- of the side walls 13 and I4 of Each of'the classifying pockets .2l'to 22 has. at each side the familiar transparent wall po'rtion or window 41 through which the hindered settling or teeter condition within the pocket can be observed. Thepre'ssure chamber 32 underlying each 01 the pockets 20 to "is provided it one side with the familiar hand hole cover 42.-

having an outlet 46 intermediate its side 5111' '01 t tank u' there' about halfwaybetween the top'and the bottoml thereof a horizontally extending channel iron 42 serving. as reinforcement members and as a bracket means for thereby supporting the entire tankunit upon a suitable supporting structure herein not shown. l

In order to supplythe hydraulic liquid or water for the classifying operation to each of the classifying pockets 2lrto 22, the tank is provided with a familiar horizontally extending distribution header 5| having lateral branch connections 5| leading to the respective pressure chambers 24. The connection proper is here represented by a hose portion 5|. ter through each branch connection 5| is controllable as by adjustable clamps pinching the hose connections 5|.

At one end the header 50 is closed as by a screw cap 53; at the otherend it connects with a vertical pipe or standpipe 54 leading into and being fed from a constant level water container 55 supplyingthe pressure water under a corresponding static hydraulic head. A control valve 56 is provided in the standpipe 54.

Mounted 'upon and extending over the top-of the tank III is a bracket construction or framework. 51 for the purpose of supporting thereon automatic s nds discharge and density control devices for framework is shown to comprise a series of parallel transverse members 51' extending across the tank, brackets 58 rising from some of the transverse members 51', each such bracket comprising a pair ofrising standards 58 and Il interconnected at the topby a crosspiece '59. e brack-.

ets 58 in turn are interconnected at the top by a pair of rails or angle irons 60 and 60' extending horizontally and longitudinally of'the tank -and substantially over a length corresponding to the containing standpipe SI for each of the pockets 2! to28 as by means of a bracket 22. The lower end of the standpipe 6i terminates a distance d above the constriction plate 29. Each standpipe 6| comprises a length L of its upper end portion column above the level of the suspendedsolids bath or column in the classifying pocket into which the standpipe 6| extends.

The fluctuations of this super-elevation of the clean liquid column in pipe'il furnishes the primary and hydraulically controlled impulse for effecting the automatic control of the sands dischargevalve and thereby automatic density control for the grading of the sands fraction in the various classifying pockets, all as will'be more clearly described below.

Since the. invention proper residestin an improved device for the automatic density and sands discharge control, such'device is more clearly il- .lustrated in Fig. 8 showing the arrangement of a sub-assembly comprising the control devices proper and environmental parts directly associated therewith. This sub-assembly appears in Fig. 8 in a somewhat enlarged scale, showing the train of componentparts constituting. the control device as'being detached from the environment of the tank strilcture shown in Fig. 3. I The function-of the control devices'is further The flow rate of hydraulic wa-- ach of the pocket 2! t 28. 'Thisinsisted-by wa of wiring diagrams (see Figs. 11, 12, 13, 14) presenting the complete operating cycle or, train of events whereby the automatic I correction of density and of sands discharge in the respective-classifying pockets is effected.

Referring to Fig. 8, the automatic control device .according'to this invention as applied to one classifying pocket comprises a train of component parts, in whichthe clear liquid pipe 6| represents 1 the initial element through which and from which the primary corrective impulse emanates to set system as represented by the units 65 and l0.

the corrective operating cycle going. The pipe 6| has a hydraulic'operating connection by way .of a branch pipe '63 leading to the interior of a bellows 6.4 whichln turn constitutes the controlling part of a primary potentiometer unit 65 comprising furthermainly a primary potentiometer I unit as being contained in a housing as; It will be understood that the changes in the shape of the bellows 64, that is, contraction or expansion, are caused by variations in hydraulic pressure from the clean liquid column or super-elevation in thepipe6l.

. The movement transmitting means 61 in the primary potentiometer unit.65 (see Fig. 7) comprise a 'stem .lifl coaxialwith and fixed'to the free end of the bellows 64 and extending slidably through the wall of'housing 69 and into contact with a double-armed lever 6I fulcrumed as at 61, andhaving a relatively shorter arm 61? and a longer arm 61, the latter arm being-engaged by the stem '61 from below. The extreme end of the longer arm 61 is rigidly connected with the aforementioned contact arm 88 extending at right angles therefrom, while the opposite end portion of \the shorter arm 61 has anchored thereon as at 61 a tension coilispring 61 the opposite end of that spring'being fastened to a coaxial screw 61 threaded as at '61 into the wall of the housing 69 for adjusting the tension of the spring 61 The tension of the spring insures operating contact with the stem 61.

- Also, by adjusting'the spring tension it is possi- ,so'that the control circuits may-be operated in the manner to be further described.

The operative connection between the armature shaft 13* and the valve stem 35 is illustrated in Figs. 6,- '7, 5, 4. It comprises winding member I9 partially resembling a pulley having at its circumference a holloyv lug portion 86 through which extends the flexible member or wire 35 the free end portion 8! of which i adjustably fixed in a terminal or anchoring block 92 by means of a set screw 93. The other end portion 84 of the wire extends coaxially into the free end portion of the valve stem 35 and is shown to be'embedded therein as at 85 and thus be fixedly connected therewith.

' Due to this flexible wire connection 35 9. ro-

tation of the armature shaft Iii for instance through an angle of 160 as shown in Fig. 4 will accordingly lift or lower the valve to' the extent that the wire iswoundup on or unwound from the member 19.

The functioning of the control devices as represented by the units 65 and 10 will be understood from, and described by reference to the I wiring diagrams in Figs; ll to 14. It will be noted ble to influence or adjust or time the degree of response of the control devices relative to the primary-impulse as represented by the hydraulically induced changes of the bellows 64.

Changes in the condition of the. potentiometer unit 65, induced by changes in'the position of i the contact arm 6B, affect. in, turn the condition of a secondaryor controller potentiometer unit 16 by way of an electrical three-wire connection W comprising individual wires or leads 19, 10 and 16. i

, The unit 16 comprise a housing H in which are contained a secondary potentiometer resistance coil 12, a motor 1 3ha'ving an armature shaft I3? operatively connected with the valve stem 35 a by a wire or flexible linear element 35, movement transmitting means 14 such as the arm 14 fixed .on the armature shaft, the link 74",; and arm 14, for translating rotation of the armature shaft 13 into movement of a contact arm. 15'

slidableu-pon the secondary potentiometer resistance coil 12, and finally a solenoid controlled double throw switch is not visible in the '1 show ing of the unit I 19, but adequately shown in the wiring diagrams in Figs. 11 to 14. 7

.Wires 1'! and I8 leading into the unit "'0 furnish extraneous electrical power to the controlthat identical parts shown in Fig. 7- on, the one hand and in Figs. 11 to 14 on the other hand, are designated by identical numerals. Also, for the purpose of readily identifying and correlating parts of. the wiring diagram to the mechanical showing of the control devices in Fig. '7, respectlve parts of the diagram have been boxed in by dot-and-dash lines, and the boxed-in portions designated by the, same numerals as the corresponding control units shown in Fig. 8, namely, by the numerals 65 and 10 respectively.

The electrical control system embodied in the wiring diagram Fig. 11,. and its principle of op- I eration or its operating cycle as ,illustrated in Figs. 12, 13, 14, will now be described.

T e system comprises a source of electrical power as represented by the transformer 86 from 8F and 88, where they split to form two parallel 1 circuits, namely a potentiometer circuit involving'the potentiometer resistance coils 66 and I2, and a motor circuit for stopping and starting the motor 13.

The potentiometer circuit comprises the conductor 10 leading from terminal 81 in unit 19 to terminal as in unit as, a conductor 90 leading within unit 65 from terminal 89 to contact arm 68 engaging the primary potentiometer resistance coil 66 at a point intermediate the ends thereof i thi instance. 4 5 By way of this contact arm 68 the circuit splits into twoparallel branches R1 and R2. The one branch Ri comprises the portion pi of the resistance coil 66, a conductor 9|, leading therefrom to a terminal 92 within the unit t me conductor a 16'? leading from terminal 92- in unit 65 to the,

unit '10, where it connects up with one end of a solenoid coil 93; a conductor 94 within the unit I0 leading from the other end of the solenoid coil 93 to the terminal 95,0f theresistance coil 12.

' and the portion n of the resistance coil 12 terminatmg at the contact arm 15 from "which the circuit is completed by way of-a conductor 96 leading to terminal 88. The other branch R2 of the potentiometer circuit leading from the contact arm 68 comprises the complementary. portion n of the resistance coil 66, leading through conductor 9'! to a terminal 91 within the unit .66, the conductor 10" leading from the terminal 91 to the unit 10 to connect up withone end of a solenoid coil 98, a conductor 99 leading from In Fig. 11 both solenoid coils 93 and 98 appear equally energized due .to the balanced condition of the two branches R1 and R2 of the potentiometer circuit, exerting equal forceupon both cores IN and I02 and thus holding the switch member 16 balanced in a neutral or.open position with respect to contactterminals I03 and. I04. 1

In Fig. 12 a change in the position of the contact arm 68 has taken place due to a contraction of the bellows 64 whereby unequal resistance portions 125 and p6 of the resistance coil 66 are established. Thence, the solenoid coil 93 becomes more strongly energized than the coil 98, unbalancing .the cores I0! and I02 and causing the switch member 16 to be thrown into a circuit closing position by contact with the terminal I03,

starting the motor to rotate in a corresponding the latter continues to be moved until it will have I reached the Fig. 13. position whereby it establishes unequal portions 1n and pa of the resistance coil 12. This re-establishes the balanced condition of both branches R1 and R2 of the potenti- 'ing the portion p; and 134 01 the resistance 'coil 66',

.and thus the balanced condition of the potentiometer branchcircuitsR'iand R2.

It will be understood that the control cycle just described by reference to the diagrams in Figs.

11 to 14 effects the positioning or corrective adjustment of the sands discharge valve, resulting in density control, since the valve stem '36 is operatively connected with and moved by the rotation of the armature shaft 13, and since the operation of the armature shaft 13' is in turn the result of primaryhydrauiically induced impulses from the classifier pocket causing contraction or expansion of thebellows 64. I

The aforementioned circuit R1 (in Fig. lll'consists of the portion P1 of resistance coil 66, the conductor 9 I, terminal 92, conductor 10, solenoid coil 93, conductor 94, terminal 96, and the portion pa of the resistance coil 12. I

The circuit R2 (in Fig. 11) consists of the portion m of resistance coil 66, terminal 91, conductor 10 solenoid coil 99, conductor 99, terminal I00, and the portion n of the resistance coil 12, The circuitsRi and R2 inthis phase are in balanced condition relative to one another. In Fig. l2 the respective portions of the resistance coil 66 are. shown to have changed to uneven portions as and pa, while the portions 93 and p4 of 0 In Fig. 13 theportions pa and no of resistancecoil 66 have remained the same as in Fig. 12,

, but the portions of resistance coil 12 have changed ometer circuit, causing both solenoid coils 93 and 99 to' be equally energized and thus to restore 'the balanced condition of the cores IN and I02, and the balanced or neutral position of the switch member 16. While in the unit 10 in Fig. 1 the motion transmitting means 14 are shown in the form of linkage, they are shown in Figs. 11 to 1 4 to n and m respectively. The circuits R1 and R: are again in balanced condition relative to one another. In Fig; 14 the portions of the resistance coil 66 have again reverted to the Fig. 11 condition, while the portions of the resistance coil- 12 have remained the same as in Fig. 13. That is, the

circuits R1 and B: have again been thrown out of balance relative to one another.

While the double-throw switch 16 is shown (see 2 Figs. 11 to 14) to be included in the structural unit' that is represented by the unit 10, it may be inor neutral Fig. 11 position interrupting the motor circuit and stopping the movement of the arms;- tureshaft 13.

In Fig. 14 the contact arm' so is shownto have a been restored to the Fig. 11 position due to expansion of the bellows 64. This again unbalances the conditions in the branches, R1 and R2 of the potentiometer circuit with respect to one another, sending a greater current through the branch B2 engaging the solenoid coil 98 more strongly, caus- ;ing the switch member 16 to be thrown into a cirpartment or pocket 20. A stream of the feed ing relocation of the wiring.

f Operation" The sizing operation in principle functions as follows: l

The feed material which may be a liquid suspension of liquid and sands or other granular material to be sized, is received in the feedcompartment 38 which acts as a'quieting or disseminating chamber for the next following comsuspension or slurry thus flows across the submerged wall or partition 40, and on across the shallow pocket 20 to form a pool or bath therein,

into which rises hydraulic liquid through the perforated bottom 36 from the liquid pressure chamber or compartment 31, to effect a preliminary teetering and mobilizing ,of solids suspended in the bath. The stream of feed suspenterminal 91 through the switch member 16; and

by m" of terminal m, motor windings ms, to

have been returned to the Fig. 11 position, restorsion then passes on ma gradually widening bed (see Figs. 9 and 10) over the classifying pockets 2| to 29 proper. Assuming that the overflow edge of the-weir portion 45 defines the depth of the stream of slurry flowing across the classifying feed stream relative to thetop'edgeof the parti-' tion 40 is si, and the depth relative to the top stream of the suspension must pass.

edge of the partition l8'of the classifying pockets is Sa, the difierential Ss'-S1 being designated as S2. 3 i

The function of the classifying pockets in intercepting and grading the sands from the feed suspension flowing over them, is well known in Y principle. Each pocket has maintained in it a different upflow velocity of hydraulic or teeter liquid, the velocity in the initial andnarrowest pocket 21 being the hi hest and in the last and widest pocket" the lowest. Teeter conditions are maintained in the pool or bath in each pocket corresponding to a depth "T," each pocket repre senting' a classification zone over which the The teeter 61,9 establish hydraulic balance. The resultantcondition ineach pool or bath of theclassification I pockets is so controlled that substantially only. a

certain grade or size fraction from the entire size range of the sand gravitate to the bottom of the pocket, where it is removed by way of the automatically controlled valve 3| and outlet passage 33.

The automatic discharge control by way of the valve ii, in effect, represents a means for'automati'cally maintaining a certain density condition in the teeter bath or bed, and an individual .automatic valve control device for this purpose is provided for each pocket. Such a device will correctively respond tov ary the setting .or posi-. tion ofthe valve body 34 to accelerate or retard the discharge of the sands fraction from the pocket. Corrective action takes place for instance when for any reason, for instance due to a fluctuation in the quantity or character of the feed suspension, there occurs an'undue accumula tion of'solids in the bath, the density of the bathincreases which oflfers increased resistance to the liquid column in the stand-pipe communicating with and balanced by the teeter bath or bed. A relatively small change of density in the teeter bed of the pocket will thus manifest itself in an appreciable change in the height of the clear liquid column which change in turn is utilized to cause changes in the setting of the sands discharge valve. v In as much as the present invention resides more specifically in improvements in devices for effecting the automatic corrective control or setlower super-elevation of clear liquid effects a core responding compression or shortening of the bellows Bl which istransmitted to the contact member 68, moving it to the Fig-I12 position, and thereby upsetting the balance of the system. The

amount of dislocation of the contact member 68 thus'produced is in proportion to the. amount of change in super-elevation caused by the density change in the teeter bed. This causes the switch actuating {solenoids s3 and 9 8'to be unequally energized and to close the motor switch IS.

The armature shaft consequently rotates for a time interval causing a compensatory movement of the contact member 15, equivalent to the movement which the contact member 68'has al-- ready performed. Thus, when the contact mem-' ber Iireaches the position shown in Fig. 13, the

equilibrium condition of the electrical system will have been restored, as the solenoids 93 and 88 again become equally energized, causing the switch member It 'to revert to'its' balanced or 1 incoming hydraulic water. This allintum causes acorresponding increase of height of a clearneutral position, whereby the armature shaft. is

again stopped leaving the valve 3| ina somewhat further lowered position, namely, sufiiciently nearer its seat --to discharge sands at a decreased rate whereby the'desired' density of the,

teeter bed and thus the desired classifying efiect thereof is again-restored. In this way, the'valve 40 II will have been lowered correctivel'y in properting of the discharge valve in response to fluctuations or changes indensity conditions in the teeter bed or a pocket, the operation of the improved device will now bedescribed: While feed suspensions of a certain unlform composition and flowing at a certain uniform rate enter the narrow feed end of the tank, there will maintain a corresponding open-position setting ot'the valve bod 34 allowing a fraction of the sands of 'a-certain size-to pass out'of the pocket at a steady rate. .As long as all these conditions remain uniform, the teeter and density conditions eflecting this particular grading eisdwin remain substantially uniform. This position of thevalve ,body It is maintained by the sustained pressure from the then super-elevation of the clear liquid column in standpipe 6i acting through the branch pipe .63 .upon the bellows 64 within the housing of unit 65, and by the corresponding position of the armature shaft 13' connected with U caused to rotate in a directionopposite to that in Fig. 12 until it will have brought the contact .tion and-in response to the amount of change insuper-elevation that was caused by the densitydecrease in'the teeter bed. This condition .will

maintain as long as the condition of the slurry feed and of the suppl pressure of the teeter waterremains unchanged. I

In Fig. 14 it is,assu'mcd that the density in the teeter bed has increased to van.extent whereby there will be effected increase in the clean water super-elevation, that will cause the bellows 64 to expand, restoring the contactmember G8 to the I position which it is also shown to-assume in Fig.

11. This again causes unbalancing and unequal energization of the solenoids 93 and 38, causin the switch member 16 to close, although in a direction opposite to that, shown in Fig. 12-.

Consequently, the armature shaft 13' will be,

member 15 back to the position'sho'wn in Fig. 11,

thereby restoring the balanced condition which energizes the solenoids 93 and 9a to an equaldegreet: This restores" the switch member 16 to neutral, which stops the armature shaft 13. and leaves the position of valve 3| somewhat higher oil-seat, to increasethe discharge of sands sufiioftheteeterbed.

ciently to restore the, esireddensity-condition The corrective operating cally perform and repeat itself' for' the pool or.

theavalve stem 35. condition (see.Flg. 11)..

is maintained due to the then electrically balanced condition of the primary unit ii and the secondary unit It relative to one another,

' bath. in eachclassiiying pocket, so thetav desired average uniform density condition andfluniiorm size -grading is automatlcallymaintained in the or'el 7 5 operation of each pocket.

cycle will automati- I claim:

1. Control apparatus of the class described for association with a pool of suspendedsolids to be classified by hindered settling to which such solids are continually fed and from which fractions of solids are continually discharged by one path from the bottom of the pool and by another path from the top of the pool, a column 'of clean liquid balanced by the density of the pool to a super-; elevation above the top of the pool which varies with the density thereof, a vertically movable valve controlling. the rate of discharge of the solids fraction-through a valve seat in the bottom of the pool, and automatic means for stabilizing the density of the pool at a predetermined normal to ensure accurate size classification of solids therein whichcomprises a reversible electric motor in a power circuit adapted to raise and lower the valve to adjusted positions while off its seat, means movable upwardly by rise of the superelevation incident to increased density above normal of the pool and movable downwardly as the risen super-elevation begins to fall; andconjoint means operated by movement .of the movable means for controlling the motor to (I) raise with its power from the outside source the unseated valve a distance proportional to the rise of superelevation for thus efiecting a proportional inlevel of the super-elevation at which the valve is again, arrested for decreasing the release of solids from the pool and increasing the density thereof.

2. Apparatus according to claim 1-, in which the armature shaft of the motor has a' flexible 7 connection with said valve and unwinds relative to said shaft in accordance withthe'deg'ree of rotation of the motor;

r 3. Apparatus according to claim 1, in which the armature shaft of the motor has a motion translating connection with said valve comprising a pulley fixed on said armature shaft, and a wire element having one end anchored upon said pulley and the other end connected with said valve.

4. Apparatus according to'claim 1, in which there is provided a motion translating connection between the armature shaftof the motor and said valve comprising a pulley. fixed on said shaft, a .wire element connecting the valve with said pulley, and means for anchoring the wire element upon said pulley including 8., lug at the periphery of said pulley and having a hole for the p ssage of said wire element therethroush, and an anchoring member adjustably fastened to the free end of said wire element emerging from saidlug.

Apparatus according to claim 1 ,with the ad!- dition of settable actuating means for the motor having a potentiometer circuit, and including a first and a second resistance coil, a pair of solenoids in said circuit, a double throw switch controlled by said solenoids for operating the motor in two directions, a contact arm movable on said first resistance coil that is settable by said impulse transmitting means; a contact arm movable on said second resistance coil and settable by movement of the motor armature, thestructural arrangement being such that said first resistance coil and the associated contact arm are combined )hindered settling, means for continually feeding suspended solids thereto, means for continually discharging -fractionated .larger solids or sands from the bottom'of the pool, means for continually overflowing from the upper sectionof such pool another fraction of smaller solids 'or'fines, means for continually supplying liquid under hy- .draulic pressure to mobilize solids insuch pool.-

means for establishing and maintaining a column of clean liquid balanced by the density of thepool to a super-elevation above the top of the pool which super-elevation varies with the density of the pool, a vertically movable valve controlling the rate of discharge of the solids fraction through a valve seat in the bottom of the pool, and automatic means for stabilizing the density,

y of the-pool at a predetermined normal to ensure accurate size classification of solids therein characterizedby a reversible prime mover operated from an outside source of power adapted to-raise and lower the valve to adjusted positions while level of the super-elevation at which the valve is again arrested for decreasing the release of solids from the pool and increasing the density thereof;

off its' seat-means movable upwardly by rise of source the unseated valvea distance proportional to the rise'of super-elevation'for thus effecting a proportional increase in the rate of release of solids from the pool for lowering the density of V the pool and consequently the risen super-'elevation, 2) to arrest the valve when the risen. superelevation reaches a predetermined height, and 3) to lower. the raised valvea distance less than to valve-seating position,'but proportional to the fall of elevation from the level of the 'super-elevation at which the rising valvewas arrested to'the 7. Apparatus according to claim 6 with the addition of means for adjusting the degree ofresponsiveness of the movable means to changes of "super-elevation.

8. Apparatus according to claim 6 with the addition that the prime mover raises the unseated valve a distance proportional to but less than the c rise of super-elevation. i.

9. Apparatus of the class described having a basin adapted to hold a varyinedensity pool of suspended solids to be classified by hindered settling to which such solids are continually fed and from which fractionsof solids are continually discharged by one pathfrom the bottom of'the pool and by another-path f m the top ofthe pool, a

column of clean'liqui extending to a superelevation above the top of thepool and balanced bythe density-of thepool forithus indicating in magnification changes in density. of the pool, a

vertically movable valve controlling the rate of discharge ofthe solids ,fraction through a valve seat inthe bottom section' of the basin, autc- .8 mac means stabilizing the'density o! the vwill. at a predetermined normal to ensure accurate size classification of solids therein which comprises a reversible prime mover operated from an outside source of power adapted to raise and lower as well as stop the valve while ofiits seat; means ('1) movable in one direction by rise of the superelevation beyond a predetermined minimum distance incident to increased density above normal of the pool, (2) automatically stoppable' thereafter, and (3) movable in'the opposite direction as risen super-elevation falls beyond a predetermined minimum distance; and conloint means operated by the movable means for controlling the prime mover to arrest the moving valve whereby the valve will have been moved a distance less than the distance moved by the level oi! the super-elevation, and to restart movement of the valve at a constant rate in the same direction as the super-elevation but only after the super-elevation shall have moved in that direction a predetermined minimum distance from the elevation of the valve-arresting change of direction-'- A V 10. Apparatus of the class described for association with a. basin adapted to hold a varying v density pool of suspended solids to be classified by hindered settling to whichsuch solids are continually fed and from which fractions of solids reaches a predetermined minimum'extent of rise for thus effecting increase in the rate oirelease of solids from the pool for lowering the density of the pool and consequently the risen superelevation, (2) to arrest the valve thereafter, and

(3) to lower the arrested valve after such time as falling super-elevation reaches a predetermined Y minimum of fall until the super-elevation again rises for decreasing the release of solids from the pool and increasing the density thereof.

11. Apparatus oi the class described for association with a basin adapted to hold a varying density pool of suspended solids to be classified by hindered settling to which such solids are continually fed and from which fractions of solids are continually discharged by one path from the bottom of the pool and by another path from the top of the pool, a column of clean liquid balanced by and changing with the density of the pool to a super-elevation above the top .of the pool, a vertically movable valve controlling the rate of discharge of the solids fraction through a E valve seat in the bottom of the pool but movable Y super-elevation,

a-distance less than the change of height of the and automatic means for stabilizing the density 'of-the pool at a predetermined normal to ensure accurate size classification of solids therein which comprises a reversible prime mover operated from an outside source of power adapted to raise and lower the valve to adjusted positions while oil its seat, pressure-responsive a-distance' less than'the change of height of the r super-elevation, lizing the density er. the pool at a predetermined normal to ensure accurate size classification of and automatic means for stabisolids therein which comprises a reversible prime mover operated from an outside source of power adapted to raise and lower the valve to adjusted positions while oi! its seat, pressure-responsive means movable in one direction by rise of the super elevation "incident to increased density of the pool above normal and movable in the opposite'direction as'the risen super-elevation begins to tall; and means operated by movement of the pressure-responsive means for selectively conmeans movable in one direction by rise of the super-elevation incident to increased density of the pool above normal and movable in the opposite direction as the risen super-elevation begins to fall; means operated by movement of the pressure-responsive means 'in one direction to operate the prime mover to raise the unseated valve after such time as rise of super-elevation reaches a predetermined minimumextent' of rise and for arresting movement of the valve thereafter, means operated by movement of the pressure-responsive means in the opposite direction to operate the prime mover to apply power in" reverse to lower the unseated valve after such time as falling super-elevation reaches' a predetermined minimum tall and for arresting movetrolling the prime mover 1). to raise the unseated valve after such time as rise ofsuper-elevation ment of the valve thereafter, and means torcontrolling the sensitiveness of the response of the .prime mover operating means to the pressureresp'ons ive means.

I A. HAAGENBEN.

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