US2362674A

US2362674A - Apparatus for handling spinning solutions

Info

Publication number: US2362674A
Application number: US413578A
Authority: US
Inventors: Spangler Lynwill Kelsey; Pratt Harold Conrad
Original assignee: American Viscose Corp
Current assignee: Akzo Nobel UK PLC
Priority date: 1941-10-04
Filing date: 1941-10-04
Publication date: 1944-11-14
Anticipated expiration: 1961-11-14
Also published as: GB553490A

Description

Nov. 14, 1944. LR SPANGLER ErAL, 2,362,674

APPARATUS FOR HANDLING SPINNING SOLUTIONS Filed Oct. 4. 1941 "F5 ZA n v 2 n n w A a1. a 2- INVENTOR, LYNW/LL KELSEYEPANELER BY Hwum Ecuvmu PRATT Patented Nov. 14, 1944 APPARATUS FOR HANDLING SPINNING' SOLUTIONS Lynwill Kelsey Spangler and Harold Conrad Pratt, Parkersburg, W. Va, assignors to American Viscose Corporation, Wilmington, Del., a

corporation of Delaware Application October 4, 1941, Serial No. 413,578

8 Claims. (Cl. 18-8) 4 This invention relates tothe handling of unstable chemical dispersions such as are employed in spinning artificial filaments, The invention is particularly concerned with the problem of reducing non-uniformity of viscose or other spinning solutions to be delivered to the spinning machines.- Such solutions or dispersions are prepared by a procedure including steps of ageing or ripening under carefully controlled conditions, filtering and blending after which they are led into a set of supply tanks. The viscose dispersions, each having the'desired ripeness, are led into the empty tanks of the set in predetermined order while the full tanks of the set are discharging, usually one at a time, in corresponding order so that the viscose supplied to the spinning machine is substantially uniform in ripeness,

and hence in chemical and physical and more particularly inviscosity.

However, it is the practice in emptying any given tank to leave a small part of the viscose in the bottom thereof in order to prevent the entraining of air bubbles in the viscose as it is discharged from the tank. The air bubbles would be entrained by virtue of the tendency of the viscose to form a vortex in the last portion to be properties,

removed, and the amount of the viscose necessary to be left in the tank in order to prevent any entrainment of air is quite large, especially in tanks whose bottoms are formed in the shape of relatively shallow cones.

This residual viscose left in the bottom of the tank, the so-called "heel or tankbottom," undergoes further ripening so that its ripeness is considerably advanced with respect to that of the next batch of viscose with which the tank is to be filled, and, in the large proportions that such bottoms have heretofore been left in such tanks, the heel does not become mixed to any substantial extent within the new batch of viscose. Because of the fact that the final physical char- 1 acteristics of the filamentary material depend upon the uniformity of the ripeness of the viscose or other solution from which it is spun, it is highly desirable to reduce as far as possible the amount of heel or tank bottom that is necessary to be left within any given supply tank.

"The amount of heel to be left has heretofore been reduced somewhat by the practice of opening the next supply tank tethepump as soon as the level in any given supply tank being dischargedby the pump becomes dangerously low, but this procedure is inadequate so that quite a sizeable mains as a heel.

quantity of viscose still re- It is an object of the invention to provide a novel method by which most of the heel is removed from any given-supply tank slowly at a positively controlled rate without permitting entrance of air into the material being discharged and without aifecting the uniformity of delivery rate to the spinning machines. It is a further object of the invention to provide a novel arrangement of apparatusto effectuate the removal of the heel in the manner hereinafter described. Further objects of the invention will appear from the description thereof.

In-the drawing, which is of a diagrammatic character, 15

Figure 1 shows one embodiment of the invention, 7

Figures 2 to 5 inclusive show successive steps in a second embodiment of the invention, and

Figure- 6 shows a variation in the modification of Figures 2 to 5 inclusive. 7

For purposes of illustration, the description of the drawing hereinafter will refer specifically to the handling of viscose, but it is to be understood that the apparatus and procedure is applicable generally to the handling of other chemical solutions-or dispersions presenting similar problems. a

In Figure 1, there is shown diagrammatically a spinning set of six supply tanks for viscose, which are numbered in the order of discharge or withdrawal of their contents by the main pump to the spinning machine. Each of the supply tanks is provided with a connection to a compressed air line la, each of such connections being controlled by the

valves

8, 9, III, II, I2 and I3. These air valves may all be open constantly (except during filling of a tank when its valve will ordinarily be closed and the tank vented to the atmosphere) or they may be opened only to the respective tanks as they or their heels are being emptied and it is to be presumed that either of these conditions exists in the following description. The air pressure thereby assists the pumps in discharging the tanks.

The respective supply tank are connected to a ring or loop header It by means of the three-way valves l5, l6, l1, l8,.l9, and 20. This loop or ring header is connected by the pipe 2| to the pump 22 which discharges into the pipe 23 leading to the spinning machines. ment so far described has been in common use heretofore. In accordance with the invention, the respective supply tanks are connected to an auxiliary header 24 and an auxiliary pump 25 which discharges into the suction side of the The arrangemain pump 22. The flow oi. the contents of the supply tanks through the auxiliary header 24 is controlled by the

valves

26, 21, 2s, 29, an and so that large amounts of viscose will not beretained by the auxiliary lines between their.

intervals of operation.

In operation,

valves

26, 21, 28, 29, 30, and 3| are normally closed while the main body of any given tank, such as I, is being discharged. In

' r the normal operation of delivery, the three-way valve I5 of supply tank I is turned so as to open the supply tank connection into the header I4 while the three-way valves on the other supply tanks are blanked toward the respective tanks; in this way, the viscose in supply tank I is fed to the pump through both branches of the ring header I4. When the viscose in supply tank I has become relatively low and has attained a predetermined level, the three-way valve I6 on the next tank, supply tank 2, is turned to open the connection of that tank into the ring header I4, and either directly thereafter or at any time before the supply tank I approaches a dangerously low level where it tends to draw air into the lines, the three-way valve I5 is blanked toward tank I, the valve 28 is opened and the auxiliary pump 25 is operated so that the contents of supply tank I are discharged into the line at a much slower rate than would be possible were it connected directly to the main pump 22, so that most of the heel in supply tank I is discharged into the spinning line without entraining air therein. This permits of the discharge of the supply from any given tank to a far greater extent without entraining air than was heretofore possible and correspondingly reduces the heel so that subsequent filling of the tank results in much greater uniformity of the contents therein. Tank I is then filled with the next batch of viscose and the cycle just described is repeated for each of the tanks in succession as they are emptied. A valve 32 is provided in the air line Ia and is normally closed, though if additional supply tanks or sets of tanks are connected to the air line it may be opened to them.

In Figure 2 to 5 inclusive, a modified arrangement is shown in which the supply tanks of a spinning set numbered in the drawing in their order of discharge are connected as before to an air supply line Ia by the valves 8,v 8, III, II, I2,

and I3 and to a ring header I4 by means of the three-way valves I5, I8, I'I, I8, I9, and 20. The ring header I4 is connected by pipe 2I to the main pump '22 which discharges into the pipe 23 leading to the spinning machines. In accordance with the modified embodiment of the invention, the auxiliary pump 25 of relatively small discharge rateas compared to the main pump is connected across the ring header I4 so as to di-, Vide the supply tanks connected thereto into two equal groups. This auxiliary pump connection is. also supplied with the valve 33 for connecting and disconnectingthe suction side of the auxiliary pump to the ring header.

Figure 2 shows the operation while emptying the main bulk of the supply in tank I during which valve 33 is closedwhile valves I8, II, I8,

I18, and 20 are blanked toward their respective:

supply tanks in order to permit theviscose from 15 t each of m tanks, valve means for controlling tank I to flow through valve I5 into both branches of the ring header I4 to the pump 22.

when the viscose in tank I approaches a predetermined low level, valve I8 is turned in order to connect tank 2 to the header I4, as shown in Figure 3. Valve I8 connected to tank 2 is then blanked toward the auxiliary pump connection as shown in Figure 4 so that viscose from tank 2 flows only through the right branch of the ring header I4 to the pump 22. At the same time or immediately thereafter valve I5 is blanked toward th main pump and turned so as to connect tank I to the auxiliary pump line in which valve 33 isopened and the auxiliary pump 25 started. In this manner the main pump 22 is supplied chiefly from supply tank 2 while drawing a small amount from tank I as controlled by the auxil- I iary pump 25.

When the viscose in tank I has reached the lowest permissible level, pump 25 is turned 01!, valve 33 is closed, valve I5 is blanked toward viscose tank I, and valve I8 is turned to connect supply tank 2 to both branches of the ring header I4 (all as shown in Figure 5), and tank I may be refilled, after which the cycle is repeated for each successive tank.

Figure 6 shows a modification of the embodiment of the invention shown in Figures 2 t0 5 which is necessary when an odd number of supply tanks constitute a spinning set. As shown in Figure 6, the auxiliary pump is provided with a conduit having two

connections

34 and 35 to the ring header I4 on either side of the middle tank I. These two connections are necessary in order to block off the central tank I exclusively to one or the other of the pumps when either tank I or tank 6 is blocked ofi exclusively to the. other pump. Oneor the other of the two valves are shown in the drawing. While it has been stated that the pumps discharge into lines leading to spinning machines, these pipes may, it desired, first proceed to other processing devices, such as filters, before entering the spinning machines. The several supply tanks may be provided with the customary thermometer wells and pressure gages, and also with sight glasses at any desired levels or with signaling devices to indicate when designated or predetermined levels are reached by the viscose in the tank. If desired, the auxiliary and main pumps may be connected to separate motors or to a common motor, suitable reduction gearing being supplied in the latter case to adapt the motor. to the outputs desired of the two pumps.

While a preferred embodiment of the inven- -tion has been disclosed, the description is in- .tended to be illustrative only, and it is to be understood that changes and variations may be made without departing from the spirit or scope of the invention as defined by the appended claims.

the flow of the contents of each of said tanks through said header, an auxiliary header connected to each of said tanks, valve means for controlling the flow of the contents of each of said tanks through said auxiliary header, means connecting said auxiliary header to said main header, and pumping means for controlling the flow through said connecting means.

2. In apparatus of the class described, a plurality of supply tanks, a ring header connected to each of said tanks, valve means for controlling the fiow of the contents of each of said tanks through said header, an auxiliary header connected to each of said tanks, valve means for controlling the flow of the contents of each of said tanks through said auxiliary header, means for uniting the efliuents from each header, said last-mentioned means comprising a pump for controlling the rate of flow from said auxiliary header.

3. In apparatus of the class described, a plurality of tanks, a main header connected to each of said tanks, valve means for controlling the flow of contents from each of said tanks through said header, a conduit connected to said header between two of said tanks to divide the tanks into two groups, pumping means in said conduit and means for uniting the discharge of said pump with the discharge from said header.

4. In apparatus of the class described, a plurality of tanks, a main header connected to each of said tanks, valve means for controlling the flow of contents from each of said tanks through said header, a conduit connected to said header between two of said tanks'to divide the tanks into two approximately equal groups, pumping means in said conduit and means for uniting the discharge of said pump with the discharge from said header.

5. In apparatus of the character described, a plurality of tanks, 9. ring header connected to each of said tanks, a conduit connected to said header between two of said tanks to divide the tanks into two groups, pumping means in'said conduit, valve means for directing the flow from any of the tanks through the header away from said connection and valve means for directing the flow from any of the tanks on the opposite side of said connection exclusively toward said connection.

6. In apparatus of the character described, an even number of tanks, a ring header connected to each of said tanks, a conduit connected to said header between two of said tanks to divide the tanks into two equal groups, pumping means in said conduit, valve means for directing the flow from any of the tanks through the header away from said connection and valve means for directing the flow from any of the tanks on the opposite side of said connection exclusively toward said connection.

'7. In apparatus of the character described a plurality of tanks constituting an odd total number, a ring header connected to each of said tanks, a conduit connected to said header at both sides or its connections to the central tank thereby dividing the remainder of the tanks into two equal groups, pumping means connected to said conduit and valve means in said conduit for selectively connecting said pumping means to either side of said central tank, means for directing the flow from any of the tanks through the header away from said selective connection, and valve means for directing the flow from any of the tanks on the opposite side of said selective connection exclusively toward said connection, and means for uniting the discharge of said pump with the discharge from said header.

8. In apparatus of the class described, a plurality of supply tanks, a main header connected to each or said tanks, valve means for controlling the flow of the contents or each of said tanks through said header, an auxiliary header connected to each of said tanks, valve means for controlling the flow of the contents of each of said tanks through said auxiliary header, means connecting said auxiliary header to said main header,'- and means for controlling the flow through said connecting means.

LYNW'ILL KELSEY SPANGLER. HAROLD CONRAD PRATT.