US1920469A - Wool scouring - Google Patents

Description

L. D. JONES WOOL SCOURING Aug. l, 1933.

2 sheets-sheet 1 Filed June 8, 1929 NVE TOR NAN www

TTORNEY D. JONES 1,920,469

WOOL SCOURING Filed June 8. 1929 2 Sheets-Sheet 2 Aug. 1, 1933.

Patented Aug. l, 1933 UNITED STATES PATENT oEFlcE Sharples Specialty Company,

Philadelphia,

Pa., a Corporation of Delaware Application June 8, 1929. Serial No. 3S9,28l

.4l Claims.

This invention relates to wool scouring, and particularly to a process and apparatus whereby the liquor in the scouring bowls is maintained in effective condition and grease, dirt, and sol- 5 uble substances are continuously recovered from the liquor, the grease being recovered in desinable condition and in a substantially dry state. The term Wool is used herein to designate the hairy coat of various animals of .which sheep are but an example.

Raw wool contains undesirable substances which must be removed before the Wool is used and which may constitute as much as 75% of the Weight of the wool and which include grease or degres, soluble organic substances, some of which are potassium compounds, and dirt. To effect removal of these substances the Wool is scoured in a hot aqueous solution or" sodium carbonate and soap and rinsed; and if it is desired or necessary that the grease and soluble substances be recovered, they must be separately recovered free of dirt from thescouring liquor and rinsing water. In view of the large quantities of material to be removed from the wool in the scouring operation, the scouring liquor and rinsing Water are rapidly contantinated and their eectiveness is rapidly impaired. And, in View of the relatively high temperature of the scouring liquor, decomposition occurs, and delays in removal therefrom of substances ren moved from the wool thereby will result in decomposition, particularly o the grease, and cause the recovered grease to be dark in color and otherwise impaired in quality.

A feature of this invention is that removal of grease and dirt from the scouring liquor is continuous, withthe result that the degree of purity and effectiveness of the scouring liquid is maintained uniform and relatively high. An- L other feature of this invention is that the concentration in the scouring liquor with which the scouring operation is being carried on, of Watersoluble substances thereby removed from the Wool, may he controlled, With the result that after the scouring operation has proceeded for some time with a fresh batch of liquor the` substances dissolved therein frorn the Wool may be utilized to effect the results obtained by the use of soap in the liquor and the necessity for further addition of soap is minimized or eliminated. Other features of this invention are that fresh water is added to the system to compensate for liquor taken out in the wool and for liquor lost, or discarded for the purpose of controlling the concentration of soluble substances, in the puri- (Cl. SLUG) fying of the scouring liquor; and that water so added is introduced into a later rinsing operation and rinsing Water is flowed countercurrent to the path of the wool through the scouring train, as its content of soap, soda and solubie impurities increases, to the scouring operation, the liquor in the scouring operation being subjected to co nous purification. Additional features ntion reside in the steps and apparatus whereby the liquor in the scouring and rinsing steps flows countercurrent to the path of th wool.

it has been proposed to pass into a. centrifugal separator scouring liquor charged with grease, soluble substances removed from the wool, and dirt, and to separately discharge the grease and aqueous solution, While retaining the dirt in the bowl; but centrifuges rotated at sufflcient speed to effect separation of grease from the acqueous solution possess such limited capacity for retained dirt, that such centrifuges must be stopped and cleaned several times each hour, and the separate discharge of grease and aqueous solution While retaining dirt in the bowl is wholly impracticable commercially. Such a centrifugal separating operation, because of the necessity for cleaning the centrifugal bowls, is adaptable neither to continuous purification of scouring liquor nor to batch purification thereof.

.n feature oi this invention is that the purication of the scouring liquor is eected centrirugally as weil ascontinuously. Other features of this invention are that as a result of the centrifugal puriication involved, the scouring liquor is maintained suniciently pure to be eective and the grease may he recovered in a substantially dirt-free and my state, and the soluble substances removed from the wool may be recovered economically. Another feature of this invention is that the operations in volved in such purification are carried on with such promptness that the character of the subA stances recovered is not impaired. The features last mentioned include numerous details that are part of this linvention. The scouring liquor is withdrawn from the scouring operation at a point at which the concentration therein of grease, soluble substances and dirt is at a marimurn or relatively high. The Withdrawn liquor is so treated centrifugally that substantially all of the dirt and a part of the grease are removed. in a centrifugal operation in which the removal of dirt neither interrupts the operation of the centrifuge to any objectionable extent nor requires large numbers of centrifugal machinesand out impairment of its operation, and to permit of the removal of that dirt with but momentary interruption of operation. The eiiiuent that contains a reduced content of grease and is substantially free of dirt isreturned to the scouring operation without substantial loss of heat.

Thus, the liquor in the scouring operation is 'subjected to a continuous withdrawal of liquor containing a high concentration of substances removed from the wool, and that iquor is returned' to the scouring operation after being substantially freed of dirt and after its concentration of grease is-reduced and while it con- .tains substantially the same concentration of detergents as the liquor in the scouring operation, or substantially the same concentration vof detergents as it contained when it was withdrawn from the scouring operation, such detergentsbeing sodium carbonate and soap or soluble substances withdrawn from the wool and effective ...asdetergentsl This operation will maintain thescouring liquor in effective condition andaprevent the concentration of grease and dirt therein from exceeding a predetermined maximum.

Another feature of this invention is that the eiiluent containing the higher concentration of grease but substantially free of dirt is subjected to a second centrifugal operation capable of effecting a separation of the grease from the aqueous solution. Centrifuges of the type that must be used for such a separation would clog so Arapidlywith dirt; if liquor containing substantial quantities of dirt were fed to them, that such use ofthem would be impractical. One eiliuent of this-separating operation may be referred to as-wet grease in that it contains 90%.or more of particularly as fertilizer. This aqueous eiiiuent may be returnedto the scouring operation unless such return would result in building up to an undesirable degree the concentration in the scouring liquid of soluble substances removed from thewool; and, if so, the recovery of soluble substances removed from the wool is readily effected by recovering those substances from this aqueous eflluent. In this connection it is a feature of my invention that this second centrifugal operation may be carried on, in whole or in part, in such a manner that the aqueous eiiiuent is .substantially free of grease if it is not to be returned to the scouring operation. And.

another feature of my invention is that the soluble substances removed from the wool may be recovered from this aqueous eiiluent that contains a minimum of grease, by utilizing this eiiiuent in the production of steam for thevarious heatin g operations in the practicev of this invention, such as the heating of the scouring liquor and the heating of various bodies of material in the purifying operation.

Another feature of this invention is that the wet and substantially dirt-free grease obtained in the second centrifugins operation is by washing freed of detergents and of soluble substances removed -fromvthe wool. and is. by a third centrifugal step, converted into substantially dry clean grease.

In prior practise in wool scouring the scouring liquor was frequently subject to continual dilution, requiring frequent addition of detergents; and large batches of liquor accumulated that contained too much dirt and grease for further use; and frequently the liquor was ob- Jectionably dirty throughout a considerable part of the scouring operation, Purification of batches of discarded liquor has proved so dimcult that deterioration occurs before the grease can be recovered. In contrast, in the practice of this invention, the same liquor may be retained in the scouring bowls for several days and the concentration of dirt never exceeds a predetermined maximum and the scouring operation is uniform. Moreover it is possible in the practice of this invention to maintain, without .having an undesirable dirt content in the scourother and further features and advantages of this invention will be apparent from this description taken in connection with Ithe accompanying drawings which show one embodiment of my invention to which my invention is not limited and in which,

Fig. 1 shows diagrammatically apparatus embodying my invention and whereby my process maybe practised:

Fig. 2 shows in vertical section a centrifugal machine useful in the practice of my invention;

Fig. 3 shows in front elevation the apparatus shown in Fig. 2 and Fig. 4 is a detail.

Referringto the drawings a series of scouring bowls 10. l1, 12, etc. may be employed, which are not materially different from scouring bowls now in use.. and of which four or live or more may be employed in series. Each scouring bowl comprises a'tank open at the top and having its bottom formed into sediment collecting compartments 14 and having across its interior a perforated plate or screen 15 along which is advanced the wool to be washed and through which insoluble substances drop. The wool is introduced into the respective bowls in any suitable manner as by means of belt conveyors 18, 17, 18. etc.: and the wool is advanced along the screen 15 in each scouring bowl in any suitable manner, as by means of rakes 19, the teeth of which are moved by known mechanism in paths indicated by the dotted line 20. Having suiiicient aqueous solution of soap and sodium carbonate in bowl 10 to maintain the level of liquid therein approximately at the line 21 wool is fed to the conveyor 16 from which it falls into bowl 10 and is advanced throughout the length thereof until it slides over the weir 22 and between the wringer rolls genauso 26 which expel liquor that is caught in tank 2e, and troni rolls 2t the wool is tahen'by oonveyor i7 and dropped into bowl ll where it is similarly advanced until it is wrung by rolls 25, the liquid thereby removed being caught in teni- Then, the wool is. teiten by conveyor deposited in bowl l2, this procedure continuinc untill the scoured wool is finally olischarged from the last The second bowl contains sufficient detergent, usually soap, to complete the scouring the wool and to the grease in einulsii ed form; and sucin bowls in the scouring train contain rinsater. From 2e, liquor removed from uol by rolls 23 passes through pipe 27 into 28. Liquid :l tenir passed by 36 into bowl lo and .f wool deposited therein oi liquor wets the 'the scouring liquor.

1 anp through. e'

o contact 'u th yor lil.

in .hout the spray ight 'not be wetted and .i Ould float. Similaiiy each successive scouring or -rising bowl il, l2, provided with a as tens for co lecting liquor rel from the wool by the wringer rolls, and that liquor passes through pipe 35 into a tank f i which it is withdrawn by pump 3'? and passed through pipe 33 back into the .bowlrom which it came unless diverted to an earlier bowl of the train as hereinafter describe l.

From the bottom ci each settling compartment le oi bowl i6 liquor containing grease, dirt and soluble substances removed from the wool, is passed through valves 3l into pipe 32 to pump 33, which passes the 'withdrawn liquor through pipe 34 to the puriiying operation from which a part of the liquor is returned as heretoiore stated and as hereafter more clearly described.

From scouring bowl 10 liquor is withdrwn through pipe 32 for puriilcation and all oi. that liquor is not returned to the bowl and liquor is carried out in wet wool that entered that bowl in a dry state. To compensate for this, pipe 39 leads from pipe 38 to tank 2S and flow from pipe 39 is controlled by oat valve e0. Pipe 38 is also provided with a valve il that will ordinarily permit of enough, or more than enough, flow oi liquor of make-up for removal of liquor from bowl l by discharge or" wet wool therefrom and by loss or discard of liquor in the purifying operation, but if there is a sudden draught of liquor from bowl l0, as in the case of the starting up or resumption of the purifying operation, then valve 41 limits the rate at which the liquor is advanced from bowl ll to bowl and allows the deficiency in bowl 10 to be made up gradually with the result that the operation of the entire system is more uniform. Deficiencies of liquor in bowl 1l, 12, etc. are made up by flow of liquor from pipe 38 oi the respectively preceding bowl into the proper one of tanks 36. Sodium carbonate and soap are supplied to bowl 10 and also to bowl 1l for the purpose of completing the scouring therein and maintaining the grease in an emulsied state. ln bowls 12, etc. there will usually be only a rinsing operation, and fresh water is supplied to the last, or any ci such bowls, as by means of fresh water-supply pipe 42. j

The maintenance of sufllciently pure and effective scouring liquor in the scouring bowls, and also the maintenance of sufficiently pure rinsing water in the rinsing bowls, is dependent upon the nature and eiectiveness of the continuous purifying operation. The liquor withdrawn from bowl lo for purlcation is passed to a centrifugal machine, or which a suitable iorin is shown in Figs. 2 and 3, in which it is divided centriiugaily into an efxluent substantially iree of dirt and containing a reduced consent of grease, an eliuent substantially iree o o and containing an increased concentra of grease, and body or" dirt retained in t centrifuge. that a large quantity ci dirt may be retained in the rotor but may be dislodged and remet therefrom rapidly and without stopping ol e centrifugal bowl. Rut, while such a cent e will produce an aluent containing a higher co centration oi grease it is iriadyisable atten/il t to withdraw substantially; therefrom,

Thus, the liquor is passed I pipe .te threes.ghl pine into an impe rotor mounted on shalt in bearings ee and rotated in suitable inanner.. The rotor d6 comprises hub 49 and side wall 56, and surrounding hub e9 and `tlierefron'i is a truste-conical wall 5l having a i ange l52 that lies in spaced relation to the e o. wall 59 to provide an annular supply passage 53 into which liquor is discharged by pipe L35, o d which preferably is provided with varies 5e t cause liquor to rotate with the rotor. Within th interior oi rotor d6 is an annular partition 55 that is supported in any suitable manner as by brackets 56 connected to the peripheral wall o the rotor and to annular partition 55. Partition divides the interior of the rotor into a separating compartment 57 and a discharge .compartment 58, which compartments communicate through the annular passage 59 between the outer edge of partition 55 and the inner wall of rotor 46. Supply oi liquor to rotor a6 and withdrawal of liquor therefrom will be so regulatedl as to maintain the liquor in the rotor in the form of a hollow cylinder having an inner surface indicated by dotted line 60. Withdrawal of liquor having an increased grease content from rotor 46 may be eiected by skimmer 62 acting upon the surface of liquid in separating coinpartment 57 and removing an eiiiuent containing a higher concentration oi' grease. Liquid having reduced grease content may discharge, from compartment 58, over the inner edge or" annular end wall 6l of the rotor or it may be withdrawn by skimmer 63, acting upon the liquor in discharge compartment 58, there being effected in either case a removal from the rotor of an eiiiuent having a lower concentration of grease. In this connection it is pointed out that liquor of reduced grease content is thrown to the outer zone of the rotor and passes through passage 59 to compartment 58. Skimmers 62 and 63 act upon the surface of the rotating bodies of liquid as shown in Fig. 4, and are mounted for adjustment to various distances from the axis of the rotor. Thus, each skimmer slides in brackets 64 mounted on the casing 6 of the rotor and is provided with a threaded lug 65 in which is threaded a hand-operated shaft 66` that also passes through brackets 64 and is held from longitudinal motion therein by means of collars 67 that are secured to shaft 66. Thus rotation of shaft 66 effects the adjustmentof the position of the skimmers to points along a radius of the rotor. Liquid withdrawn by skimmer 63 and which is freed of dirt and contains a reduced grease con- PDO tent is passed through pipes 68 and 69 back to 61 into casing 6 drains through pipe 7 into pipe 69. Liquid withdrawn by skimmer 62 and which is freed of dirt and contains an increased concentration of grease is passed by pipe 70 to`\ a collecting tank 71 for further treatment.

After a considerable quantity of dirt has accumulated in the rotor 46, valve 8 is closed, thus cutting oif the supply of liquor to rotor 40, and valves 72 and 73 are closed, and valves 74 and 75 are opened, thus cutting off return of Aone effluent to bowl 10 and flow of the other efiluent to tank 71 and diverting both effluents to reservoir 76, and skimmer 63 is moved radially outward in rotor 46, effecting removal of liquid from rotor 46 to reservoir 76. During such complete removal some dirt may be removed by skimmer 63 and therefore that liquor is passed to reser- -voir 76v instead of being returned to bowl 10 or passed to tank 7l. Then, by means of. tool 77, which may be operated in any known manner,

' for example as shown in the application of Laurence P. Sharples, Serial No. 174,975, filed March 12th, 1927, the dirt is dislodged from the rotor during rotation thereof, and it falls into hopper 78 and is collected in some receptacle such as box 79. Then valve 80 which is normal'- ly closed, is opened and the dirty liquor that is temporarily held in reservoir 76 is fed to the rotor through pipe 45 for centrifugal treatment. When tank 76 is empty, valve 80 is closed, valve 8 is opened, and continuous purification is resumed.

Liquid in tank 71, which has a higher concentration of grease and is free of dirt, is heated, as by steam coil 88, to a higher temperature that will facilitate separation of grease from aqueous solution. Then it is passed through pipe 81 to super centrifuge 83 which may be of the type shown in Sharples Patent No. 1,320,419, and which may be rotated at speeds of the order of 15,000 R.. P. M. One effluent from this centrifuge consists of wet grease, containing about 10% of water, discharged through spout 84 and collected in bucket 85. The other elliuent, discharged through spout 87 into tank 103, consists of an aqueous solution of soluble impurities removed from the wool, and is of low grease content. This aqueous effluent will have about the same concentration of detergents as the scouring liquor in bowl 10, but will be practically free of insoluble material.

The wet grease obtained in this second cenltrifugal operation is transferred to washing tank 89. as by means of bucket 85. In this tank the wet grease is mixed with about three to five times its volume of water, as by means of cold water supplied by pipe 90 to tank 91 under the control of float valve 92, the water flowing through pipe 93 from tank 91 to tank 89. Steam coil 94 heats the contents of tank 89 and the added water so dilutes the soap content of the grease that in further treatment of the resulting mixture in super-centrifuge 95, to which the mixture is led by pipe 96 or pipe 97, the grease emulsion is broken down and the grease becomes continuous and free of water and is discharged through spout 98 as dry grease containing but a fraction of a percent of water. The aqueous component of the mixture is discharged through spout 99 from which it may be passed by pipe 100 back to that one of the bowls of the scouring train in which the liquor is of similar composition.

The scouring liquor is continuously separating grease from the wool and taking up soluble substances from the wool in the scouring operation. The scouring liquor in the scouring operation is maintained at a desired degree of purity by continuously withdrawing grease therefrom and by continuously discarding some of the liquor, which is replaced by fresh water, that contains soluble substanc taken up from the wool and contains a minimum proportion of grease.

Scouting liquor is continuously drawn from the scouring operation and subjected to centrifugal separation and an Yeffluent of that separation which contains a' reduced grease content is continuously returned to the scouring operation. The rate at which this step is carried out is so regulated as to maintain a sudiciently low grease content in the scouring liquor in bowl 10. When insoluble solids are dislodged from rotor 46 they carry with them some liquor in which soluble substances removed from the wool are in solution. The amount of scouring liquor so withdrawn from the liquor in circulation may be suiiicient to maintain a desirably low concentration of soluble substances in the scouring liquor. If not, all or part of the aqueous discharge from centrifuge 83, and which contains soluble substanc removed from the wool, may

be discarded from the system, as by discharge through drain 101 of tank 102 into which the aqueous eiiiuent of centrifuge 83 may be conducted through pipe 116. When the operation of the purifying system is so adjusted that grease is flowing into the buckets 85 at a sumciently rapid rat-e to maintain at a suiiiciently low value the concentration of grease in scouring bowl 10, the amount of aqueous solution discharging through spout 87 may be greater than the amount thereof that must be discarded in order to maintain a sufficiently low concentration of soluble substances in a scouring liquor. In such case that lpart of the aqueous solution produced by the second centrifuging operation which need not be discarded for the purpose of keeping down the concentration of soluble substances in bowl 10, is returned to the scouring train as by being passed from tank 103 by means of pipes 104, 105 and 106 to scouring bowl 10 or 11, according to which bowl contains scouring liquor having a composition most like the aqueous eiiiuent collected in tank 103.

Liquor that is so discarded contains watersoluble substances removed from the wool and those substances can only be recovered by evaporation of the solution. However, the solution is I very dilute and the cost of evaporating it is greater than the value of the substances in it. It is a feature of this invention that these substances are recovered, and it is a further feature of this invention that the recovery of these substances is effected without materially increasing the cost of the operation of the purifying steps described, although it has been economically impracticable heretofore to recover these Watersoluble substances. To this end it is a feature of taining 0.2% grease.

pipe 112. Inasmuch as is desirable that aqueous solution passing to the evaporator should be as free as possible of grease, a second centrifuge' 82 may be included in the second centrifuging operation and operated at low capacity in order to insure a maximum of grease removal from the aqueous eflluerft passing therefrom through spout 86 into tank 102 from which the aqueous solution is passed by pump 114 to evaporator 107. Grease discharged through spout 115 may be collected in bucket 85 and conveyed to tank 89. It is to be expected that the passing of all aqueous solution from spout 86 to evaporator 107 will effect s uciently rapid removal of soluble substances from the scouring liquor, butif not, additional aqueous solution may be passed to evaporator 107 from tank 103 by means of pipe 116.

In the operation of this invention itis to be understood that soap and sodium carbonate are to be added to the scouring bowls as required, scouring bowl 10 usually containing five or ten times as much soap as scouring bowl 11, and scouring bowl 10 containing about as much sodium carbonate as it does soap. Throughout the apparatus valves are employed as required and as indicated in the drawings.

To assist in the understanding and practice oi' this invention, but with the intention that my invention is not limited to the proportions described in this example, an actual operation of this invention was as follows:

In this operation wool was scoured at the rate of one thousand pounds per hour, the wool being Colorado wool. `Three thousand gallons of liquor were maintained in the first scouring bowl. The scouring and purifying operations above described were carried out, and after a few hours of operation the concentration of impurities in the scouring bowl ceased to increase; and at this equilibrium point the scouring liquor in the first bowl contained 0.5% of soap, 0.3% of sodium carbonate, 1.0% of grease, and soluble impurities and dirt removed from the wool. Thus in the scouring of this Colorado wool the purifying operation was capable of maintaining this low degree of impurity in the scouring liquor of the rstbowl. In the operationgdescribed one thousand gallons of liquor per hour were withdrawn from the first scouring bowl and passed to the purifying operation. In the first centrifuging operation this withdrawn scouring liquor was divided into a first fraction constituting 70% of the withdrawn liquor and containing .05% of grease, and asecond fraction constituting 30% of the withdrawn liquor and containing 2.2% of grease. Dirt was removed from the first centrifuge once each hour to the extent of about two hundred pounds each hour. The first fraction, in view of its composition, was returned to the rst scouring bowl. The difference between the one thousand gallons per hour withdrawn from the first scouring bowl and the 700 gallons per hour so returned thereto was made up by counterflow of liquid from the succeeding bowls of the train to the first bowl. 'Ihe second fraction was passed on to the second .centrifuging operation in which it was divided into a Wet-grease fraction consisting of about grease and a second fraction con- The second fraction was evaporated and as a result it was found that the withdrawn scouring liquor contained 3% to 4% of soluble impurities. f The aqueous solution withdrawn from the second centrifuge for the purpose of recovering soluble impurities may be treated in a spray drying operation for the purpose of obtaining those impurities in a substantially dry state. The wet-grease fraction after washing and centrifugal treatment consisted of about 50 pounds of dry grease for each one thousand pounds of liquor withdrawn from the scouring bowl. The wool scoured in the operation described was an example of a fairly clean wool prior to scouring.

I claim:

1. In apparatus for scouring wool, a series of scouring bowls adapted for the passage of wool successively therethrough, a wringer associated with each bowl and adapted to wring wool passing therefrom, a tank associated with each bowl and with the wringer associated therewith and adapted to collect scouringliquor removed from the wool thereby, a pipe leading to each tank from the tank associated with the next succeeding bowl and provided with a valve, a float in each tank for controlling said valve in said pipe leading thereto, and means for passing liquor to each of said bowls of said series from the tank associated therewith.

2. In apparatus for scouring wool, aseries of scouring bowls adapted for the passage of wool successively therethrough, a wringer associated with each bowl and adapted to wring wool passing therefrom, a tankI associated`with each bowl and with the wringer associated therewith and adapted to collect scouring liquor removed from the wool thereby, a pipe leading to each tank from the tank associated with the next succeeding bowl and provided with a Valve, a float in each tank for controlling said valve in said pipe leading thereto, means for supplying fresh liquid to the last of said bowls, and means for withdrawing contaminated liquidfrom the first of said bowls.

3. In apparatus for scouring wool, a scouring bowl, means for separating scouring liquor into dirt-free liquor and dirt, means for passing liquor from said bowl to said means, a high-speed centrifugal separator adapted for separating grease from liquor discharged from said first means, pipes for conducting liquor discharged from said rst means to said high-speed centrifugal separator, an evaporator for aqueoussolution discharged from said high-speed centrifugal separator, and pipes for conducting steam from said evaporator into heat exchange relation with liquor in said scouring bowl.

4. In an apparatus for scouring wool, a scouring bowl, means for separating scouring liquor into dirt-free liquor and dirt, means for passing 135 liquor from said bowl to said means, a highspeed centrifugal separator adapted for separating grease from liquor discharged from said ilrst means, conduits including a heating tank for passing liquor discharged from said first means`140 to said high-speed centrifugal separator, an evaporator for aqueous-solution vdischarged from said high-speed centrifugal separator, and pipes for conducting steam from said evaporator into heat exchange relation with liquor in said heating tank.

LEO D. JONES.

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