US2500123A - Air filtering apparatus - Google Patents

Description

- March 7, 1950 E. c. GWALTNEY ETAL 2,500,123

AIR FILTERING APPARATUS Filed April 27, 1945 6 Sheets-Sheet l March 7,, 1950 v c. GWALTNEY ETAL 2,500,123

AIR FILTERING APPARATUS 6 Sheets-Sheet 2 Filed April 27, 1945 AIR FILTERING APPARATUS 6 Sheets-Sheet 3 Filed April 27, 1945 March 7, 1950 E. c. GWALTNEY ETAL.

AIR FILTERING APPARATUS 6 Sheets-Sheet 5 Filed April 27, 1945 March 1950 E. c. GWALTNEY ETAL 2,500,123

AIR FILTERING APPARATUS G Sheets-Sheet 6 Filed April 2'7, 1945 Patented Mar. 7, 1950 AIR FILTERING APPARATUS Eugene C. Gwaltney, Biddeford, and William Shaw and Eliot B. MacLean, Saco, Maine, assignors to Saco-Lowell Shops, Boston, Mass, a

corporation of Maine Application April 27, 1945, Serial No. 590,592

8 Claims. 1

This invention relates to air filters, and is more especially concerned with the requirements of apparatus of this type intended for use in textile mills.

In all of the earlier operations in connection with the preparation of cotton fibers for spinning, including bale breaking, opening, picking and cleaning, the cotton is conveyed in a current of air. These operations involve the separation of the fiber from the dirt, leaf, sand, and other foreign materials, most of which is carried along by the air stream and remains in the latter even after the cotton has been separated from the air stream, either in the machines themselves or in the condensers. In order to provide suitable working conditions in any room where such operations are performed, it is necessary to filter the air used in connection with them before it can be returned to the room.

The type of filter which has proved most practical for this purpose is that shown in Patents Nos. 2,057,369, 2,206,297, and 2,315,278. In all of them the filtering medium or mat is composed mainly, and usually entirely, of fibers filtered out of the air stream itself. While these filters represent a highly important and practical solution for the air filtering problem as it exists in such places as picking and opening rooms, nevertheless it is recognized that they do not take out all of the fine dirt, and an unfortunate fact is that the line silica dust is not completely removed by any of the filters employed in textile mills. This material when inhaled into the lungs of the workers is highly irritating and, so far as we now know, the human body has no way of getting rid of it.

Practical considerations complicating this filtering problem are the facts that th filtering operation must be continuous and that the volume of air the filters must handle is very large, a single picker fan, for example, discharging approximately 1000 to 1200 cubic feet of air per minute when in operation.

The present invention is especially concerned with the problems presented by the foregoing considerations, and it aims to devise a thoroughiy practical solution for those problems.

The manner in which it is proposed to accomplish this object will be readily understood from the following description when read in connection with the accompanying drawings, and the novel features will be particularly pointed out in the-appended claims.

3 In the drawings:

Fig. 1 is a plan view of an opening and picking machine organization including filtering apparatus embodying this invention and illustrating a typical use for apparatus of this type;

Fig. 2 is a plan view, partly in horizontal section, of a filtering structure embodying this invention;

Fig. 3 is a vertical, sectional View taken approximately on the line 3-3, Fig. 2;

Fig. 4 is a vertical, sectional view taken approximately on the line 4- of Fig. 8;

Fig. 5 is an end view of a secondary filter unit embodying features of this invention;

Fig. 6 is a vertical, sectional view through one of the outlets of the secondary filtering unit illustrating the means for releasably supporting a filtering bag;

Fig. 7 is a front elevation of a portion of the secondary unit shown in Fig. 5; Fig. '7, however, being on a larger scale;

Fig. 8 is a vertical, sectional view through the main filter unit;

Fig. 9 is a side elevation, with some parts broken away, of the main filter unit;

Fig. 10 is a vertical, sectional view showing details of the main filter drum and parts associated therewith;

Fig. 11 is a sectional view taken at the edge of the filter drum, showing the air seal used at the ends of the drum;

Fig. 12 is a front elevation of certain elements of the drive for the filter drum; and

Fig. 13 is a side view of the parts of the driving mechanism shown in Fig. 12.

Referring first to Fig. 1, a typical opening and picking system is there shown in which filtering apparatus embodying this invention is incorporated. It comprises a series of bale breakers B delivering cotton to a single feed table T from which it is carried into a vertical opener V, and is then transferred through the pipe 2 to a condenser C of a common commercial form. The blower with which this condenser is equipped creates the suction which picks up the cotton from the delivery end of the feed table, carries it into the opener V, and then through the pipe 2 to the condenser C for the lattice opener L0. The air discharged from the blower of this condenser is led directly back under the pipe 2 into a primary filter unit 1. This air contains considerable fiber and much dirt, and the air which flows through the filter and is discharged therefrom is led through pipe connections 6 to a secondary filter unit f of a different form, and which is adapted to take out practically all of 3 the fine dirt carried by the air stream which enters it.

In this particular system, also, the cotton acted upon by the lattice opener is carried through the suction pipe 8 to a condenser C which drops it into the feed hopper of a single process picker system P locateddirectly under the pipe 8. The condenser, as usual; includes a' blower creating the suction which produces the air current through the pipe 8, and the exhaust.

air from the condenser is led back through a pipe III to a filter F, with which is associated a secondary filter F, these two units being like those shown at J and 1" respectively. The fil-- tered air discharged from the secondary units F and f flows directly into the picker room, but the filters have extracted both the fiber and the dirt from it so thoroughly that'it is entirely suitable for reuse.

The primary unit F with the secondary unit F associated with it in. a. unitary structure is illustrated in Figs. 2 and 3. The former is a continuous filter of the rotary self-cleaning type, similar to those shown in the last two patents above mentioned, but it involvesnovelfeatures of construction. It comprises a rotary filtering drum I2 enclosed in a casing I 3, the details being shown more clearly in Figs. 8 and 9, as willlater be described. The air to be filtered is led into the casing through an intake I 4 where it fiows around the greater part .of the circumference of the cylindrical drum I2, through the peripheral surface of said drum into the interior of it, and then out through the open ends of this member. The surface of the drum is of a. foraminousnature which screens out the fiber very thorou hly. As this operation continues, the fiber collects on the surface of the screen,.coooerating with it to form a mat which, when established, is anef-f fective filtering medium. As the mat builds up and the drum is slowly revolved. it comes within the range of operation of two stripper rolls .I 5'-I 5" which revolve in opposite directions and remove- Successive the mat gradually from the cylinder. portions of the drum leaving the stripper rolls are brought into the range of operation of a cleaning brush I6 which serves to take off the dirt or fiber adhering to the screen.

In this region adjacent to the brush, the screen is protectedfrom suction by the fact that the entire space through which it passes is substantially isolated, partly by the roll I5 and the usual sealing flaps, and partly, also, :by the portion of the casing cooperating with these elements to enclose this area. Two clean-out doors are provided at the bottom of the'chamber'in which the drum I2 revolves, one indicatedat w and hinged at its upper edge, but normally closed by the pivoted latch .r, while the other is hinged at its right hand edge to swing downwardly and is closed by the latch 1 The details of construction of the filter drum are better illustratedin Figs. 9 and 10. As shown in the latter figure, the drumcomprisestwoend' from it, the." latter: being integral. with airing .4 section 22 which is bolted to one of the partitions I3, Fig. 8, of the main casing I3.

The operating mechanism for the drum comprises a cam 25, Fig. 9, mounted on a shaft 26 which is driven from a motor 23, Fig. 2, supported on a shelf 24 at one side of the air intake pipe I 4. This cam runs in contact with a cam follower roll carried by an arm 2! fast on'a'rock shaft 28 which is supported in bearings at the front or intake side of the casing I3. A second arm 29 fast on this shaft carries a weight which operates to hold the roll on the arm 27 continuously against the periphery of the cam. Another arm 39 also secured on said rock shaft is provided with a series of holes spaced therealong, in any one of which the pivot pin for a link 3I may be secured. Its opposite end is pivoted to an arm 32 loose on the shaft 33. The pivot pin secured to the arm just mentioned carries a dog or pawl 34, Figs. 8 and 9, which rests by gravity on the toothed edge of a ratchet wheel 35 rigidly secured to said shaft 33. Consequently, as the cam is revolved, the motion so imparted to the arm and pawl 34 gives'the ratchet wheel 35 and the shaft 33 an intermittent rotative movement; The design of the cam is such that the wheel 35 is revolved slowly most of the time. A holding pawl S, Fig. 9, also engages the ratchet-wheel and prevents reverse movement of it.

Sprocket and chain connections 31, Figs. 8 and 9, between the shaft 33 and the shaft of the clearer roll :5 drive the latter, and additional gear connections between the two clearer rolls I5'and I5 at the opposite side of the machine drive the latter roll. Also, on the shaft of the clearer roll I5 is a pinion 40, Fig. 8, meshing with and driving a gear M on the end of the shaft I8 of the filter drum. It should also be observed that the shaft'33 supports the brush I6. Consequently, all the driven parts of the filter structure derive their power from the cam 25 and motor 23.

In this connection it maybe pointed out that,

because the two clearer rolls I5 and I 5 must have some relative separating movement to accommodate variations in thickness of the web which they remove from the filter drum, the shaft of the second roll I5 is mounted in slidable bearings which are pressed yieldingly toward the companion roll I5 by springs, one of which is shown in Fig. 13 at 61. Also, for this same reason. the two roll shafts are not geared directly to each other but are connected through intermediate gears which permit the yielding movement of this roll I5 toward and from its cooperating roll I5.

. As best shown in Figs. 12 and 13, the shaft l5 carries a pinion I5a, meshing with another pinion I5b directly above it, and the latter meshes constantly with and drives a third pinion I which also is in constant mesh with a fourth pinion I503 fast on the roll shaft I5. Thus the drive from the roll I5 to its companion shaft is continuous and positive, but still permits the necessary yielding action between the two rolls to accommodate the feeding of a web varying substantially in thickness.

A novel means for'sealing the ends of the-drum I2 against the-escape of dust-laden air through the joint between the partition or casing members I3 and the peripheral surface of the end rings I'I, isbest shown in Fig. 11. Each ring'is recessed circumferentially atits outer edge, as shown at I T, to receive a circular seal'IEl. This member comprisesa core made of wire; leather, or any other suitable material, around which'is wrapped a covering of some fibrous sheet materiaL-such. as

felt or leather. The margins are folded back together, face to face, and are secured in a recessed portion of the annular frame piece 22 by screws or rivets l9. These frame members 22 are bolted in position after the drum has been properly placed in the casing, and, in connection with this operation, the seal automatically is properly positioned in the groove ll" provided for it, where it makes a very effective closure for the joint between the drum and the stationary cam ring 22 which releasably holds the sealing ring l9 against the end ring I! of the drum.

The space in the casing is divided by partitions into the filtering chamber G, Figs. 3 and 4, in which the drum revolves, and end chambers I-II-I, Fig, 2, into Which the air flows from the open ends of the drum 22. From these chambers the air enters another chamber or passage I, immediately above the filtering chamber, and then is discharged through an opening J. When both the primary and secondary sections of the filter are built into an integral unit, as in Figs. 2 and 3, the opening J admits the air directly into the casing of the secondary unit F. This unit comprises a distributor or header 44, Figs. 2 and 3, having a chamber K into which the air flows freely from the outlet J of the casing 13. Except for this outlet the casing 44 is completely closed on its top, ends, and sides, but its bottom or floor is provided with several outlets (in this instance four), each eouipped with a fixture or fitting 45 adapted for the attachment thereto of a bag 46. The latter may conveniently be made of a tightly woven fabric, napped on its inner surface. The bag is of generally cylindrical form with a closed bottom, and it is fastened at its top to a ring 41, Fig. 6. which is provided with a flared neck around which the mouth of the bag can be conveniently tied or secured by a spring, or in any other convenient manner. The fitting or fixture 65 also includes a metal ring of angular section and an internal plain ring it fastened to it by screws. a thick layer of felt being secured between these two parts. Its u per edge acts as a seal for the cover 48 of the outlet and its lower edge engages the upper surface of the bag ring 41' and seals the space between it and the fixture 45.

In order to secure the bag to the fixture 45 for quick attachment thereto or removal therefrom, each of the rings 4'! is provided with a rearwardly extending fork 50, Fig. 6, notched at its lower side to receive a pin which is supported in an extending arm, which is shown at 52 in Fig. 6. Th s arm is made integral with the fixture 45 and the fork projects into both sides of the arm. At the opposite side of the fixture it is provided with a latch 53, pivoted at 5 1, to swing into the space between the fingers of a forked extension 55. which is exactly like that shown at 50, and is also made integral with the ring 41. The lower ends of these fingers are notched to receive a pin 56 on the latch 53.

When the parts are in the relationship shown in Fig. 6. they look the ring 41 and the bag secured to it, in their operative relationship to the fixture 45. However, by swinging the latch 53 in a clockwise direction, the left-hand end of the ring may be released, and then by pulling the ring slightly toward the left it may be completely disconnected from the fixture and the contents of its bag may be emptied into any convenient receptacle. Thereafter it may be returned to its operative position by a reversal of the operations just described.

the filter elements themselves in this secondary As above stated, the filtering operation must be continuous, and for this purpose the primary unit is made of the self-cleaning type. The secondary unit, however, includes filtering bags which must be emptied at intervals. For this purpose, and in order not to interrupt the filtering operation, several of these bags are used, and provision is made for cutting any one of them out of the air stream without interrupting its flow to the others. It is for this purpose that the covers 48 are provided for the respective outlets.

As shown in Fig. 6, the cover 48 is loosely secured by a bolt 58 to one end of an arm 60, the opposite end of which is rigidly secured to the rock shaft 6! which extends horizontally across the casing 44 just above its floor. It projects through the front of the casing, its forward end being reduced in diameter at that point. Outside the casing a handle 62 is secured rigidly to it, as shown in Fig. 6. The handle includes a plunger having a knob 63 at its outer end, with a spring (not shown) urging it inwardly, so that it can enter either one of two holes formed in the segmental guide plate 64, Fig. '7, which is secured to the front face of the casing 44. When the handle is down the cover also is in its down or closed position, as shown in Fig. 6, but when the handle is swung up and its plunger is entered in the hole 65, Fig. '7, the cover is then looked in its open position. By loosely mounting the cover plate 48 on the arm 60, it is free to seat itself tightly upon the upper edge of the felt ring clamped between the parts 45 and 45'.

A typical application of this invention is illustrated in Fig. 1. As so used, the air stre m carrying lint and dust flows initially into the primary fi ter wh ch will take out in the neighborhood of of the solid material and. under some circumstances, may remove even a higher percentage. From this filtering unit the air stream with the very fine residual dust entrained in it. goes into the secondary or bag filter unit which removes practically all of th s foreign material. Almost no fiber passes through the first filter. and this is important because any great amount of material of this nature would load up the bags too rapidly. At stated intervals the bags are removed. one at a time, and emptied. This operation takes only a moment for any indivi dual bag. If it is desired to make such removal while the pickers or other units with which the filtering apparatus is associated continue in operation, that can readily be done simply by closing off the air stream from the bag to be removed, emptying it, replacing it, and then opening the cover again for that particular bag. And these operations can be repeated with the other three bags.

While the preferrd filter is that in which both the primary and secondary units are combined in a single structure, as shown for example in Figs. 2 and 3, it is often necessary, or desirable, in some mills, to instal a filter unit where there is not room for this combined structure. Under such circumstances the arrangement shown in Fig. 1 may be used where the main filter unit f is placed in the position most efiicient for its operation, and the supplemental unit f is connected with it through a pipe, such as that shown at B. In such an arrangement the pipe just mentioned opens into a small casing which is connected with, and secured to, the header 44, just as is the casing at IS in the construction shown in Figs. 2 and 3. It will also be evident that while i uriit'are bags,'these may beireplacedby cylinders or other elementsequivalent to the bags.

It should be observed that this combination of a continuously operating filter. in which the filter mat is built up of fiber taken out of the air stream itself, and a supplemental or secondary unit into which only the fine dirt is delivered, maximum use is made of those functions of the two types of filters which each is admirably adapted to perform. The combination of them eliminates the faults and deficiencies of both, while combining their virtues. The end result is to filter the air so'thoroughly that it is entirely suitable for return to the opening, picking or other room from which it was originally taken.

iile we have herein shown and described a preferred embodiment'of our invention, it will be evident that the invention may be embodied in somewhat different forms without departing from the spirit or scope thereof.

Having thus described our invention, what we desire to claim as new is:

1. An air filtering apparatus corn rising a rotary open-ended filtering drum, a casing in which said drum is mounted, said casing being constructed to conduct the air to be filtered into contact with the peripheral surface of said drum but to confine said contact substantially to sei surface, said drum having end members supporting the peripheral surface of the drum, and said members each having a central hub, an outer ring and arms connecting the hub with the ring, a shaft extending through and secured to said hubs, and spiders secured to portions of s'aid'casing and positioned outside the ends of said drum, said spiders having hub portions supporting bearings in which said shaft is mounted.

2. An air filtering apparatus comprising a 1'0- tary open-ended filtering drum, a casing in which said drum is mounted, said casing being constructed to conduct the air to be filtered into contact with the peripheral surface of said drum but to confine said contact substantially to said surface whereby lint filtered out of the air stream by said drum will build up on the peripheral surface thereof and form a filter mat, a pair of stripper rolls extending parallel to the peripheral surface of saiddrum at one side thereof, camdriven mechanism for revolving said rolls to cause them to remove said mat gradually from said drum, means supporting one of said rolls for yielding movement toward and from the other, said driving means for the rolls including gearing positively connecting them and arranged to drive them approximately continuously notwithstanding the relative movement of said stripper rolls to accommodate wide variations in the thickness of the material removed from the drum by them.

3. An air filtering apparatus comprising a rotary, open-ended filtering drum, mechanism for revolving said drum, a casing in which said drum is mounted, said drum having end rings grooved circumferentially in their outer end surfaces, and air sealing rings secured to said casing and each comprising a core with a strip of sealing material folded around it, the edges of said strip being fastened to said casing and lateral surfaces of said material where it is wrapped around the core lying snugly in said grooves in the end rings of the drum.

' 4. An air filtering apparatus comprising a rotary open-ended fiiteringdrum, mechanism for revolvingsaiddrum; a casing having a filtering chamber in: which; said: drum; is. mounted; the

casing being constructed to conductair to-be filtered into contact with the'peripheral surface of said drum but to confine said contact substantially to said surface, the casing. also including end chambers into which the: air flows from the respectiveopen ends of said drum, said casing including afourth chamber into which said end chambers conduct the air, a secondary bag-type filter unit comprising a header having a plurality of outlets located side by side, means for conducting the air from said fourth chamber into said header, said header outlets being formed in fixtures mounted in the wall of. said header and constructed for the releasable attachment thereto of individual filtering bags, hinged covers associated with the respective fixtures for closing and opening said outlets, and handles, outside of said header, connected with said respective covers and operable to move them into their open or closed positions selectively, whereby the air stream may be shut off from any individual bag, when desired, to remove or replace it.

5. An air filtering apparatus comprising a rotary open-ended filtering drum, mechanism for revolving said drum, a stationary casing in which said drum is mounted, said drum having end rings, the outer surfaces of which are grooved circiunferentially, air sealing rings mounted on said casing and having continuous inner edge portions of fibrous material extending into said grooves to seal the joint between the ends of said drum and the casing, and clamping rings releasably securing said sealing rings to said casing and in their cooperative relationship to said end rings of the drum.

6. An air filtering apparatus comprising a rotary open-ended filtering drum, a casing in which said drum is mounted, said casing being constructed to conduct the air to be filtered into contact with the peripheral surface of said drum but to confine said contact substantially to said surface, cam-driven pawl and ratchet mechanism for revolving said drum, said mechanism including a cam follower and a cam having a developed surface cooperating therewith to impart substantially uniform rotative motion to said drum approximately continuously.

7. An air filtering apparatus comprising a r0- tary open-ended filtering drum, mechanism for revolving said drum, a casing having a filtering chamber in which said drum is mounted, the casing being constructed to conduct air to be filtered into contact with the peripheral filtering surface of said drum but to confine said contact substantially to said surface, the casing also including end chambers into which the air flows from the respective open ends of said drum, said casing including a fourth chamber into which said end chambers conduct the air, a secondary bag-type filter unit comprising a header into which the air flows from said fourth chamber, said header being provided with plurality of outlets, each outlet including a fixture constructed for the releasable attachment thereto of a filter bag, each of said bags having a ring to which its open end is secured, means for releasably securing the rings to said respective fixtures, and means operable from outside of said header for selectively closing said outlets for the removal and replacement of the individual bags while the filtering operation continues uninterruptedly.

8. An air filteringapparatus'comprising'a ro tary open-ended filtering drum, mechanism :for.

revolving said drum, a casinghaving a filtering chamber in which said drumis mounted, the casing being constructed to conduct air to be filtered into contact with the peripheral filtering surface of said drum but to confine said contact substantially to said surface, the casing also including end chambers into which the air flows from the respective open ends of said drum, said casing including a fourth chamber into which said end chambers conduct the air, a secondary bag-type filter unit comprising a header having a plurality of outlets located side by side, means for conducting the air from said fourth chamber into said head, said header outlets being constructed for the releasable attachment thereto of individual filtering bags, and means in said header operable to control selectively the delivery of air to said outlets so that any bag can be removed and replaced without interrupting the operation of the filtering system.

EUGENE C. GWALTNEY.

WILLIAM SHAW.

ELIOT B. MACLEAN.

10 REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 821,819 Neuman May 29, 1906 844,842 Anderson Feb, 19, 1907 940,076 Seaver Nov. 16, 1909 1,444,092 Anderson et a1. Feb. 6, 1923 1,479,392 McGowan Jan. 1, 1924 1,930,890 Wallace Oct. 17, 1933 2,009,140 Knowlton July 23, 1935 2,081,685 Straus May 25, 1937 2,228,129 Stephano Jan. '7, 1941 2,299,022 Kinard Oct. 13, 1942 2,315,278 Shaw Mar. 30, 1943

Images