Method and apparatus fob continu
US 2176705 A
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Description (OCR text may contain errors)
R. E. DERBY FOREIGN SUBSTANCES FROM WEBS OF FIBROUS MATERIAL Filed Feb. 16,
METHOD AND APPARATUS FOR CONTINUOUSLY REMOVING OLEAGINOUS AND Get. 17. 1939.
lnvemor. Roland E. Der by b WMkW ATTys.
UNITED STATES PATENT OFFICE METHOD AND APPARATUS FOR CONTINU- OUSLY REMOVING OLEAGINOUS AND FOREIGN SUBSTANGES FROM WEBS OF FIBROUS MATERIAL Roland E. Derby, Tyngsboro, Mass, assignor to M. T. Stevens & Sons 00., North Andover, Mass., a corporation of Massachusetts Application February 16, 1939, Serial No. 256.773
This invention relates 'to a method and apparatus for removing oleaginous and other foreign substances progressively from a web of fibrous material. The term web of fibrous material includes cloth woven or knitted or otherwise formed of various fibres, a plurality of separate strands such as yarn, slubbing or the like, or any fibrous material which may move continuously as a result of its own construction or with the aid of a flexible carrier. The invention is particularly applicable to treating such material as it comes from the loommspinning frame, card, or comb and thereby preparing it in better condition for subsequent treatments.
The invention has for its particular object effectively to remove from the web of fibrous material all traces of oleaginous substances, tar,
tinting pigments or other foreign matter which are detrimental to the finishing operations and to the appearance of the finished material. It is customary for a sheep owner. to identify his product by stamping upon the wool certain insignia with paint or tar or a tar-containing mixture and more or less of this marking material remains upon the wool and yields with difliculty to the usual wool-scouring treatments. It is customary also to apply difierent tints which are insoluble pigments to yarns in order for the manufacturer to identify and distinguish similar yarns and these tints are removed with difiiculty in the finishing operations.
The invention enables foreign substances such as referred to and others to be removed without soap-scouring operations which are expensive and time-consuming and which frequently fail completely to remove the foreign substances.
The invention has a further important object in eliminating the pollution of water from woolen mills by eliminating the practice of pumping soap liquors and undesirable foreign matter into the water because the foreign substances removed by this invention settle and are shoveled out as sludge. v
The present invention further has for its object to enable fabric to be treated immediately market.
ing and recovering the solvent employed and returning it to the system.
While the invention in its broader features or any mixtures of these three. Small percentages of other solvents may be mixed with these solvents. In fact, any mixture of a non-inflammable, chlorinated hydrocarbon with a flammable solvent, which is still non-inflammable as a mixture, will have its major portion consisting of a chlorinated hydrocarbon. The chlorinated hydrocarbons as a class have some cleansing action and, if commercially available and suitable for the particular operation, may be used for the cleansing to the extent that they have a cleansing function.
The invention'further has for its object effectively to recover or reclaim the solvent and particularly with the solvents preferred by separating water from the condensed solvent by means of gravity.
With the method and apparatus of the inven tion, the webof fibrous material passes continuously and progressively through a bath of the solvent and an important feature of the invention resides in the feature of extracting progressively by direct application of suction to the web of fibrous material after it leaves the solvent bath the principal part of the solvent, together with the foreign substances remaining in the web. It will thus be seen that the principle involved is that the air pressure upon one face of the web in the zone where the extraction of the solvent takes place is maintained sufliciently less than that upon the other face of the web to 'effect'tlie desired extraction. A further important feature resides in finally removing any solvent then remaining in the web by heat treatment to volatilize this solvent and by separating the web and the thus volatilized solvent.
These and other objects and features of the invention will appear more fully from the accompanying description and drawingv and will be particularly pointed out in the claims.
In the drawing:
Fig. 1 is a view mainly in elevation and partially in vertical cross section illustrating a preferred form of apparatus embodying the invention and suitable for carrying out the method.
Fig. 2 is a detail partially broken away showing the construction at one end of the vacuum slotted tube.
The illustration of the apparatus is more or less schematic because, except as otherwise herein noted, the details of construction may be varied as required. Furthermore, the various elements of the apparatus may be arranged and located in accordance with the conditions prevailing in the building where they are located, it being desirable that the cloth should be arranged to pass in a straight line from the point where it enters to the point where it leaves the apparatus. The portion of the apparatus through which the cloth passes is supported by suitable means on the floor I while the solvent recovery portions of the apparatus are preferably located beneath this floor on a lower floor or in a pit or chamber provided for-the purpose. The materials required will be of a kind suitable for the construction .of such an apparatus and for its support and many of the features are of standard construction. Those portions of the apparatus which may be subject to the corrosive action of the solvent are preferably formed of or lined with stainless steel or other suitable material resistant to such corrosive action.
The cloth 2 as it enters the apparatus passes between a pair of brushes 3 geared together and one of which is driven by a belt 4 from a pulley 5 on a countershaft 6, the brushes and countersh aft being journalled in a suitable framework 1 supported from the floor I. These brushes act to remove from the cloth any loose fibres which are discharged into trays 8 beneath. After passing the brmhes, the cloth passes around a guide roll 9 and thence around an expander roll III,
which may be of any suitable character and which acts in the usual manner to keep the cloth stretched widthwise. From the expander roll, the cloth passes into the chamber where it is treated with the solvent.
This solvent-treating chamber II is shown as enclosed by a metal cabinet of irregular shape closed or sealed against the escape of vapor to the atmosphere. The seal at the admission end is provided by a series of flexible members I2 connected at one edge to an upstanding wall I3 of the cabinet and acting to press the web of cloth at their opposite edges against the opposed upstanding guiding wall I4 of the cabinet. A similar sealing construction is provided by the flexible members I5 between the horizontal parallel walls I6 at the exit end of the cabinet.
A series of partitions of progressively greater height herein shown as two in number, I1 and I8, divide the cabinet at the bottom into a plurality, in this case three, of tanks for the solvent.. A plurality of guide rolls I9 are journalled trans- .versely of the cabinet near the bottoms of these tanks and a plurality of similar guide rolls 20 are similarly journalled near the top of thecabinet. A pair of feed rolls 2| are journalled in the rearward upper portion of the cabinet, are geared together, and the lower is driven by a belt 22 from a pulley 23.
The cloth, after passing through the seal into the chamber, is led down around the first roll I9, up over the first roll 28, thence down around the next roll I9, and so on down around the final roll I9 from whence it passes up around the upper feed roll 2|, between the feed rolls, around the lower feed roll 2| and out through the seal at the exit of the cabinet.
The horizontal walls I6 forming the exit of the solvent-treating cabinet are connected to a cabinet 'or casing 24 of suitable dimensions forming an enclosed heating chamber 25. In this chamber. are transversely journalled a plurality of heated metal drums 26, 21, 28, 29 and 30 geared together in sequence with one of the drums, as 28, driven by a belt 3| from a pulley 31. The pulleys 32 and 23 are shown as mounted upon a shaft on which is also mounted a pulley 33 driven by a belt 34 from the shaft 35 of a motor or other source of power. A feed roll 36 is mounted on the same shaft as the pulleys 23, 32 and 33 and is geared to a cooperating feed roll 31.
The cloth, after passing the seal I5, enters the heating chamber, passes around the feed roll 31 between it and the feed roll 36, thence around the feed roll 36 and successively around the heating drums 25, 21, 28, 29 and 30. From thence it passes around a guide roll 38 up through a. narrow slotted extension 39 at the top of the heating cabinet and thence out between feed rolls 40 geared together and the lower one of which is shown as driven by a belt 4| from a pulley 42 on the drum 29. The counter-shaft 6, already referred to, is conveniently driven by a belt 43 from a pulley connected to the lower feed roll 40. It will thus be seen that the feed rolls 2|, the feed rolls 36 and 31, and the feed roll 40 act to draw the cloth through the solvent-treating chamber,. through the heating chamber and out from the apparatus and that the various driven elements are all conveniently driven directly or indirectly from the motor shaft 35 and it will be understood that where belts and pulleys have been referred to, sprocket chains or similar positive driving mechanisms may be employed. The cloth is thus fed continuously and at the same rate of speed through the solvent-containing tanks and through the heating chamber.
The solvent is supplied continuously to the deepest tank at the right from a reservoir shown as a tank 44 mounted on the framework above the cabinet I I through a pipe 45 provided with a regulating valve 46. A rotometer 41 of suitable standard construction is located in the pipe 45 to measure and indicate the rate of flow of the solvent discharged from the reservoir into the tank at the right.
An amount of the solvent is permitted to flow continuously from the reservoir at a rate which will cause it continuously to overflow the partitions I8 and I1 into the successively shallower tanks and finally to flow from the shallowest tank through a pipe 48 provided with a suitable strainer 49 into a boiler or still 58 in which the solvent is vaporized as hereinafter described.
The valve 49 is provided to adjust the rate of overflow of the solvent in coordination with the supply of fresh solvent to the deepest tank and thereby to maintain a continuous and uniform flow of the solvent through successive tanks in a direction counter to the direction in which the cloth is passing through the successive tanks. By reason of this arrangement the cloth is progressively passed through tanks of solvent of increasing purity sothat as the cloth leaves the deepest tank, a large portion of the oleaginous materials and other deleterious materials will have been dissolved and dirt or debris adhering to the cloth will have been washed out and deposited in the tanks.
The thus partially cleansed cloth then passes traction.
over a vacuum extractor located near the exit of the solvent cabinet. This is an important feature of the apparatus because as the cloth passes over the slot of the vacuum extractor it passes through a narrow transverse zone in which the air pressure upon the one face of the cloth in said zone is maintained sufiiciently less than that upon the other face of the cloth to effect the desired ex- The apparatus thus acts to remove from the cloth not only the bulk of the solvent but also a substantial amount of the oleaginous, tarry and other foreign materials still remaining in the fabric. This vacuum extractor is shown as a tube 5| extending transversely of the cabinet and, as shown in Fig. 2, provided at the top with a slot 52 against which the cloth presses as it travels forward. At each end of the tube suitable means are provided for closing that portion of the slot not covered by the cloth. Such a means is shown in Fig. 2 as a spring 53 having attached thereto at its free end a piece of felt 54 which is drawn down by the suction to close the open portions of the slot.
This vacuum tube is connected by a pipe 55 provided with a gage 56 through an interposed strainer 51 to a suitable vacuum pump 58. The
strainer 51 is provided with a sieve 58 which acts to take out any loose fibres carried over and is manually cleansed at suitable intervals.
The vacuum pump 58 may be of any suitable construction but is preferably of the well-known type having two cooperating impellers acting continuously to produce the required vacuum which in this case has been found desirably to be on the order of twelve inches. This pump is independently and continuously driven from any suitable ,source of power. The vacuum pump discharges through a pipe 68 into a vapor cooler 8| mounted on the floor I. The pipe 62 connects the vapor cooler to the cabinet containing the solventtreating tanks so that any vapor carried along mechanically by'the entrained air into the vapor cooler and which is not condensed at ordinary pressures is returned to the solvent-treating cabinet and is therefore not wasted. The interior of the cabinet is maintained at atmospheric pressure.
The condensate formed in the vapor cooler 6| discharges through a pipe 63. This pipe 63 is shown as terminating over the middle solventcontaining tank and as provided with a branch 64 and valve 65. The branch 64 in turn divides one pipe 66 provided with a valve 61 being connected to the still 58 and the other pipe 68 provided with a valve 68 leading to a sump tank 18. Thus by manipulating the .valves. 65, 61, and 69. the condensate, ifcontaining a large amount of oleaginous, tarry or other foreign matter, may be discharged directly into the still or, if nearly clean, either into the sump tank I8 or into the solvent-containing tank in the solvent-cleaning chamber. I
Any of the solvent remaining in the cloth after it leaves the vacuum extractor is volatilized in the heating chamber as the cloth passes around the heating drums 28 to 38. These drums are fed with steam through the pipe II leading to the axes of the cylinders and discharging through a suitable vent, preferably at from thirteen to 'fifteen pounds pressure or sufficient to maintain the temperature in the heating chamber preferably above that of the boiling point of the solvent so that there shall be no danger of solvent vapor condensingupon and being carried out of the chamber with the cloth. The vapor formed in the heating chamber and any condensate formed on the walls thereof discharges at the bottom through the pipe 12.
The apparatus disclosed also comprises means for recovering or refining andrecovering sub-- stantially all of the solvent which is employed in thus cleaning the cloth.
As previously stated, the overflow from the shallowest tank is discharged into the still 58 through the pipe 48. This pipe is shown connected to a pipe |3 shown extending along beneath the floor I and entering the still at I4. The still may be heated in any suitable manner to volatilize the solvent discharged therein. As illustrated, steam is supplied from a suitable source to the pipe I5 provided with the steam trap I6, suitable gages I 1 and a valve I8 and connected to a coil or series of coils I8 located in the lower portion of the still chamber and discharging into a steam trap 88. The heat thus supplied by the coils l8 vaporizes the solvent in the still and the vapor is conducted through a pipe 8| leading from the top of the still to a condenser 82.
The still is provided at the bottom with a drain 83 and valve 84 by means of which the waste residue may be drawn oif from time to time. A branch pipe provided with a valve 86 leads from the steam pipe 15 into the still. Thus, by closing the valve I8 and opening the valves 84 and 86, steam may be blown directly into the still.
The condenser 82 is suitably supported by the uprights 81 and may be of any suitable type adapted for vapor condensation. It is shown as cooled by water supplied to the pipe 88 and forced by a suitable pump 88 through the pipe 88 through the cooling elements of the condenser. In addition, a solvent cooler 8| for cooling the solvent condensed in the condenser is provided and supported by the uprights 81 beneath the condenser. This cooler may'be of 'any suitable type and is illustrated as water-cooled. The cooling water discharges from the condenser cooling system into that of the cooler 8| through the pipe 82 and passes from the cooler through the pipe 83 to the cooling system of the vapor cooler 6| and discharges at 84. This cooling water may be returned to the'supply which is fed into the pipe 88. Thus a continuous circulation of cooling water passes through the condenser 82, the cooler 8| and the vapor cooler 6|,
A suitable air vent from the condenser is provided at 85 and prevents formation of a vacuum in the condenser.'
A water separator 86 is shown supported at 81 for the purpose of separating from the recovered solvent any water carried along therewith. The liquid solvent employed being heavier than water, the water discharge pipe 88 is located near the top of the separator while the solvent at the bottom discharges through the pipe 88 at a point I88 below the level of the water discharge 88. The respective heights of discharge I88 and 88 above the horizontal surface of contactof the liquids in the separator are in the inverse ratio of the densities of the two liquids according to the well-known principle. A drain |8I having a valve I82 is provided at the bottom of the separator. The separated solvent discharging at I88 passes through the pipe I83 into the sump tank I8. The cloth entering the system contains some moisture and additional moisture may enter the system from the air. Furthermore, when the still is blown out by the use of steam, an additional amount of moisture is carried over with the solvent vapor to the condenser. Any water thus or otherwise present in the condenser and solvent cooler is removed by this separator.
The condenser 82 discharges its condensate through the pipe I04 into the cooler 91. From the cooler the liquid solvent discharges through the pipe I05 provided with a valve I06 to the separator 96. If it is found in the operation of the system that water is separated out in the cooler 9|, the valve I06 is closed and the valve I01 in the pipe I08 opened, allowing all the water to be taken out and discharged into the separator and from thence through the waste discharge 98.
A pipe I09 open to the air and connecting, as shown, with the solvent cooler, the separator, and the sump tank frees the system of air and prevents the existence of a vacuum.
The sump tank I0 is provided with a float H0 and, when the tank has become filled to a predetermined level with the recovered solvent, this float acts to start a pump lll driven by suitable power and the pump acts to pump the solvent through the pipe H2 into the reservoir 44 which is provided with a suitable air vent H3. When the solvent has been pumped from the sump tank to the predetermined amount, the float acts to stop the pump. Thus the reservoir is continuously supplied with the fresh, recovered solvent.
During the operation of the apparatus as described, the overflow from the shallowest tank through the pipe 48, 13 carries with it the oleaginous matter, tar, tints, paints and other impurities into the still 50. The still is therefore made of sufficient capacity to contain all of the foreign matter thus extracted from the cloth for a days run in addition to the amount of solvent which is being continuously delivered to and vaporized in it. Furthermore, the solvent in the bottom of the several tanks through which the cloth passes will accumulate more or less of these impurities and it is desirable, therefore, to drain off these tanks from time to time and recover the solvent from the mixture thus drawn off. This is provided for by connections H4 opening from the bottoms of the respective tanks into the" pipe 13 and each provided with a valve I I5, thus enabling the contents of the several tanks to be collectively or simultaneously drained into the still as required.
The pipe 13 is provided near the still with a suitable strainer H6 by means of which the rate at which the liquid delivered to the still may be regulated in coosdinatipn with the rate of evaporation of the solvent in the still.
In order to recover practically all the solvent in which the various foreign materials are dissolved or suspended, the means already described provide for vaporizing the solvent from such materials after the day's run is over. To accomplish this, the valve I8 is closed and the valve 86 opened and steam blown directly into the still, thus volatilizing the solvent. The mixture of steam and vapor thus formed passes in the manner already described through the pipe 8| to the condenser 82 and the water is separated out by the separator 96.
Thus it will be seen that practically all of the solvent employed is salvaged or reclaimed and used over and over again during the normal running of the apparatus, the cabinet enclosing the solvent-treating tanks and the cabinet enclosing the heating drums being so sealed that practically no solvent vapor escapes.
Having thus described the invention, what is claimed as new, and desired to be secured by Letters Patent, is:
1. The method of removing oleaginous and other foreign substances from a continuous web of fibrous material which comprises progressively moving the web through a bath of volatile liquid solvent for oleaginous foreign substances contained in the web, progressively extracting by direct application of suction to the Web as it leaves the solvent the principal part of the solvent and the foreign substances remaining in the Web, thereafter progressively heating the web sufficiently to vaporize the solvent remaining in the web, and progressively separating the web from the said solvent vapor.
2. The method of removing oleaginous and other foreign substances from a continuous web of fibrous material as defined in claim 1, comprising continuously separating from the extracted solvent the foreign substances extracted therewith from the web.
3. The method of removing oleaginous and other foreign substances from a continuous web of fibrous material as defined in claim 1 which comprises continuously condensing the said vaporized solvent, and separating any foreign substance therefrom.
4. The method of removing oleaginous and other foreign substances from a continuous web of fibrous material which comprises progressively moving the web through a bath of a volatile liquid solvent for oleaginous foreign substances contained in the web, progressively extracting by direct application of suction to the web as it leaves the solvent the principal part of the solvent and the foreign substances remaining in the web, straining out from the matter extracted by suction fibrous and solid substances carried therein, subjecting the strained resultant to treatment for solvent recovery, and returning the recovered solvent to the bath.
5. An apparatus for removing oleaginous and other foreign substances from a web of fibrous material which comprises a closed treating chamber having a tank containing a volatile liquid solvent for oleaginous foreign substances contained in the web; a slotted tube in said treating chamber; a vacuum pump connected to said tube; and means for progressively and continuously moving the web into the treating chamber, through the solvent in the tank, over the slotted tube and out of the treating chamber.
6. An apparatus for removing oleaginous and other foreign substances from a web of fibrous material which comprises a closed treating chamber having a tank containing a volatile liquid solvent for oleaginous foreign substances contained in the web; a slotted tube in said treating chamber; a vacuum pump connected to said tube; a closed heating chamber; and means for progressively and continuously moving the web into the treating chamber, through the solvent in the tank, over the slotted tube, from the treating chamber into the heating chamber and out of the heating chamber.
7. An apparatus for removing oleaginous and other foreign substances from a web of fibrous material which comprises a closed treating chamber having a tank containing a volatile liquid solvent for oleaginous foreign substances contained in the web; a slotted tube in said treating chamber; a vacuum pump connected to said tube; a-vapor cooler into which the vacuum pump discharges; a still; a sump tank; and 7 means for discharging the condensate from the vapor cooler either into the solvent tank, the still, or the sump tank.
8. The method of removing oleaginous and other foreign substances from a continuous web of fibrous material which comprises progressive- 1y moving the web through a bath of a volatile liquid solvent for oleaginous foreign substances contained in the web, progressively passing the web as it leaves the solvent through a narrow transverse zone in which the air pressure upon one face of the web in said zone as it passes therethough is maintained sufllciently less than that upon the other face to effect the extraction of the principal part of the solvent and the foreign substances remaining in the web, and thereafter progressively separating the remainder of the solvent from the web.
9. The method of removing oleaginous and other foreign substances from a continuous web of fibrous material which comprises progressively moving the web through a bath of a volatile liquid solvent for oleaginous foreign substances contained in the web, progressively passing the web through a narrow transverse zone in which the air pressure upon one face of the web in said zone as it passes therethrough is maintained sufflciently less than that upon the other face to effect the extraction of the greater portion of the solvent from the web, removing the remainder of the solvent from the web by heating the web sufliciently to "vaporize the solvent, and conthereafter progressively separating the remainder 20 of the solvent from the web.
Rom n. 20mm.