US1628601A - Dust collector - Google Patents

Description

May 10, 1 27- DUST COLLECTOR Filed July 20, 1925 2 Sheets-Sheet l I o 22 2/ 28 Q W J. lo

I C 25 O 0 [7 Fix May 10 1927. 1,628,601

R. F. FEIND DUST COLLECTOR Filed July 20, p23 2 Sheets-Sheet 2 223mm %%V'M1 Patented May 10, 1927.

, UNITED STATES PATENT OFFICE.

ROBERT F. FEIND, OF MILWAUKEE, WISCONSIN, ASSIGNOR TO ALLIS-CHALMERS MAN- UFACTURING COMPANY, OE MILWAUKEE, WISCONSIN. A CORPORATION OF DELA- WARE.

Application filed July 20,

This invention relates in general to improvements in the art of separating solids from fluids, and relates'm'ore specifically to an improved method of and apparatus for removing solid particles from gas in which the particles are normally held in suspenslon.

An object of the invention is to pro vide a simple and efficient method of sepa rating solid particles such as dust, from gas suchas air.

Another object of the invention is to provide simple and efficient apparatus for commercially exploiting the improved method of separation."

A further object of the invention is to improve the efliciency of the method of and apparatus for separating solids and gases, which form the subject of U. S. Patent 1,168,543, granted Jan. 18, 1916.

As specifically described in the above identified patent, it has heretofore been commercial practice to utilize a plurality of separating compartments each comprising a nest of vertically suspended filter bags and means for forcing a mixture of solids and gas through the bags, in order to remove the solid particles from the gas. lVith the prior methods and apparatus the nests of filter bags are periodically cleaned by reversal of the flow of gas through the bags and by simultaneous shaking of the dust laden bags during such reversal of the flow. As it is customary in order to effect continuous separation, to clean only one nest of bags at a time, and to permit the reversed current of cleaning gas to pass through the adjacent nests of bags while these are functioning to separate and to accumulate dust, it has been found that the dust removed from the nest of bags which is being cleaned, instead of being discharged from the apparatus, is carried into the adjacent bags by the reverse current and thereby reduces the capacity and elficiency of the apparatus. It has also been found that when the bags are shaken while a current of gas is passing therethrou h, the shaking action is materially impaired due to the tension set up in the fabric by the flow of gas.

The present invention contemplates substantial elimination of these undesirable actions of the prior apparatus. With the improved method, collection of the dust is nus-r COLLECTOR.

1923. Serial No. 652,679.

effected as before, but simultaneous reversal of the flow of the gas and shaking of the bags is avoided. lyhen employing the improved method, the bags after being dust laden, are subjected to equal pressures on all sides and are shaken in a zone of balanced pressure, the reversed current of cleaning gas being passed through the bags either at a time when no shaking is being effected or during shaking but after the bulk of accumulated dust has been removed. lVith this method of operation, the bulk of the dust removed by shaking drops directly through the discharge opening and is not returned to the filtering medium by a reverse current.

A clear conception of the several steps of the improved method and of the construction and operation of apparatus capable of exploiting the same, may be had by referring to the drawings accompanying and forming a part of this specification in which like reference characters designate the same or similar parts in the various views.

Fig. 1 is a general view of a four compartment bag type dust collector.

Fig. 2 is an enlarged fragmentary central vertical section through one of the dust collecting compartments, showing the bag shaking mechanism and the control valve in normal collecting position.

Fig. 3 is an enlarged fragmentary vertical section through the control valve and actuating mechanism of one of the dust collecting compartments, showing the control valve in normal collecting position.

Fig. 4 is an enlarged fragmentary vertical section through one of the dust collecting compartments, showing the position of the bag shaking mechanism and of the control valve during final cleaning operation and with a reversed current passing through the bags.

Fig. 5 is an enlarged fragmentary vertical section through the control valve and actuating mechanism of one of the dust collecting compartments, showing the control valve in position to permit a reversed flow of air through the bags.

Fig. 6 is an enlarged fragmentary vertical section through the control valve and actuating mechanism of one of the dust collecting compartments, showing the position of the valve during cleaning of the bags and with the pressures on opposite sides thereof equalized.

The dust collector comprises in general a series of four separating compartments 2 each having a nest of vertically suspended filter bags 19 therein, and communicating with a common dust laden airsupply 3, a common pure air discharge header {hand a common dust removing bin 5. The lower extremity of the bags 19 in each of the compartments 2 are in open communication with the supply 3 and with the bin 5, and the space surrounding the bags 19 of each of the compartments 2 communicates with the header 4 through a valve casing 6 and passages 10, 11'. Each of the valve casings 6 is of cylindrical form and communicates with the interior of the adjacent compartment 2 through. a passage 11, and with the atmosphere through a passage 9. Within each of the casings 6 is located an oscillatory flow control valve 12 which is adapted to control the flow of air through the passages 9, 10, 11. The header 4 communicates with a fan or other flow producing means 7, the fan being driven by a motor 8. While all of the compartments 2 are illustrated as communicating with a common air supply 3 and discharge bin 5, it will be obvious that each of the compartments may be provided with its own individual discharge bin and source of air supply, if so desired.

Each nest of filtering bags 19 is suspended from above by means of a vertical. rod 20 having a hand wheel 28 associated therewith for the purpose of adjusting the slack in the bags 19. The rod 20 is supported upon one end of the bag shaking lever 23 the medial portion of which is pivotally supported upon the stationary frame and the opposite end of which is located in proxunity to a bag shaking cam 22. A lever positioning arm 26 pivoted to the stationary frame carries a roller which coacts with the rotatlng cam 27 mounted on the cam carrier shaft 21. The swinging extremity of the arm 26 is connected with the shaking lever 23 by means of a rod 25 and bag tensioning springs 24 as shown in Figs. 2 and 4. Each of the flow control valves 12 is mounted to oscillate upon a shaft supported 1n bearings in the casing 6 and having a weighted actuating crank 18 secured thereto, see Flgs 3, 5 and 6. A bell crank 14 pivotally associated with the stationary frame of each compartment has one arm connected to the adjacent crank 18 by means of an adustable connection 17, and has its other arm provlded with a roller 15 which is held in engagement with the surface of a valve actuatmg cam 13 by means of a spring 16.

During normal operation of the apparatus and while the dust is being accumulated upon the bags 19, the various mechanisms are positioned as shown in Figs. 2 and 3 and the motor 8 is actuating the fan 7 to induce a flow of air from the supply pipe 3 through the bags 19 and from the active compartments 2 through the passages 11, casings 6 and passages 10 to the discharge header 4. With a four compartment dust collector such as shown in Fig. 1, three of the compartments would normally be functioning to separate dust from the gas, while the fourth is having its bags 19 subjected to cleaning. As the dust laden air passes through the filtering medium of the bags 19,

the dust is removed from the air and accumulates upon the interior surfaces of the bags while the pure air is withdrawn through the passages 11, casings 6 and passages 10 and is discharged from the apparatus by means of the fan 7. The cams 13, 27 are being continuously rotated by means of the actuating shaft 21 and are so timed that they will periodically function as hereinafter, described.

During normal collecting operation, the cams 27 cooperate with the arm 26 as shown in Fig. 2, that is, with the roller of the arm 26 coacting with the cylindrical surface 01 the cam 27. With the elements thus posi tioned, the weight of the bags '19 causes tin lever 23 to swing about its pivot in a clockwise direction so that the actuating end of the lever 23 is entirely free from engagement with the lobes of the continuously rotated bag shaking cam 22. The bags 19 are thus loosely suspended during collecting operation but the fabric is stretched by the flow of gas therethrough as shown in Fig. 2. During normal collecting operation the cam 13 also cooperates with the valve actuating roller 15 as indicated in Fig. 3, the roller 15 coacting with the cylindrical portion of the cam 13 and the spring 16 functioning to hold the valve 12 in the position indicated so that direct communication is maintained between the passages 11, 10.

As each cam 13 advances to the position indicated in Fig. 6, the corresponding valve 12 is momentarily set to close both of the passages 9, 10 thereby interrupting the flow of gas through the bags 19 and permitting equalization or balancing of the pressures on the opposite sides of the bags of the compartcrnent 2 in which the valve 12 has been thus positioned. Simultaneously with the positioning of the cam 13 as shown in Fig. 6, the cam 27 becomes operative to swing the arm 26 in a counterclockwise direction thereby swinging the lever 23 in a counterclockwise direction and depressing the left hand end of the lever 23 into the path of travel of the rotating shaking cam 22. The cam 22 is then effective to impart a rapid shaking movement to the loosely suspended bags 19, the spring 24 serving to quickly depress the left hand end of the lever 23 as this lever end passes over the lobes of the of the compartment 2 in which the bags are being cleaned. With the valve 12 thus psitioned and the bags 19 still being sub jected to shaking, atmospheric air is drawn through the bags 19 in a direction reverse relative to normal collecting. This reverse current of air removes any particles which may still be lodged upon the surfaces of the bags and these are withdrawn by the cleaning current through the lower open ends of .the bags 19 and are delivered into adjacent compartments 2 which'are functioning to separate ,dust-from'the alr admitted through the inlet 3. It Will thus be noted that the nests of bags 19 function to accumulate dust for about three-fourths of the time, and

are periodically cleaned for the remaining one-fourth of the time.

It will be obvious that by neutralizing or balancing the pressures *on opposite sides of the bags 19 and by violently shaking the bags with the pressures thus neutralized,

' during preliminary cleaning, the major portion ofthe accumulated dust is discharged directly into the discharge bin 5 without being drawn into the adjacent bags which are The subsequent admission of a reverse flow of cleaning air during shaking of the bags produces effective final cleaning.-

The operation is entirely automatic and the various bag shaking and valve operating mechanisms are capable of being accurately adjusted in order to produce continuous and efficient operation of "the apparatus. By establishing a zone of balanced pressure on opposite sides of the filtering fabric during cleanin by" shaking, the fabric is entirely relievecl of tension and efiicient shaking may be effected. It will be obvious that the neutralization of the pressures may be effected either before or after, or before and after the reverse current is admitted, but the operation herein described has been found to produce highly satisfactory results.

It should be understood that it is not desired to limit the invention to the exact steps of the process herein described or to the exact details of construction of the ap paratus shown, for various modifications within the scope of the claimsmay appear to persons skilled in the art.

It is claimed and desired to secure by Letters Patent:

1. The method of separating mixed solids and gas, which comprises, establishing different pressures on opposlte sides of a filter toproduce a flow through the filtering medium in one direction, equalizing the pressures on opposite sides of the medium and repeatedly shaking the medium to remove accun'iulated solids while the pressures are equalized, andsubsequently producing a flow through the medium in the opposite direction and repeatedly shaking the medium to further remove accumulated solids during the period of reverse flow. i

2. In combination, a filter, means for producing a flow of gas through said filter in one direction, means for e ualizing the pressures on opposite sides 0? the filter, means for repeatedly shaking said filter to remove accumulated solids while the pressures thereon are equalized, means for producing a flow of gas through said filter in the opposite direction, andmeans for, again repeatedly shaking said filter to remove accumulated solids during said period of. reverse flow.

3. In combination, a filter, a rotary valve for controlling the flow of gas relative to said filter, means for positionin said valve to produce a flow through said-filter in one direction, means for adjusting said valve to e ualize the pressures on opposite sides of said filter, means for subsequently adjusting said valve to produce a flow through said

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