US3837151A

US3837151A - Baghouse dust collector

Info

Publication number: US3837151A
Application number: US00307472A
Authority: US
Inventors: R Jensen
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-11-17
Filing date: 1972-11-17
Publication date: 1974-09-24
Anticipated expiration: 1991-09-24

Abstract

This invention is directed to a baghouse dust collector of the top inlet type in which the bags are arranged in a plurality of modules, each of which contains a plurality of pairs of bags. Each bag is mounted within a concentric vertical sleeve or shell and the lower end of each bag is operably connected to the lower end of its associated sleeve through a floating type of gastight joint that adapts to variations in bag lengths. Covered access openings are provided adjacent the top and bottom of each sleeve for bag installation and removal. Cleaned gas or air is discharged from an intermediate port in each sleeve, which port also is used for the admission of reverse flow cleaning air or gas.

Description

United States Patent 91 [111 3,837,151

Jensen Sept. 24, 1974 BAGHOUSE DUST COLLECTOR [76] Inventor: Robert M. Jensen, 1457 Wisteria Primary ExammerBfemard Nozlck Dr, Ann Arbor Attorney, Agent, or FlrmTh0mas Tate [22] Filed: Nov. 17, 1972 57 ABSTRACT [21] Appl. No.: 307,472 This invention is directed to a baghouse dust collector of the top inlet type in which the bags are arranged in a plurality of modules, each of which contains a plu- 55/341 2 rality of pairs of bags. Each bag is mounted within a [58] Fie'ld "55/341445 concentric vertical sleeve or shell and the lower end of 55/361 "5 371 each bag is operably connected to the lower end of its associated sleeve through a floating type of gastight joint that adapts to variations in bag lengths. Covered 'ded adjacent the top and [56] References Cited access openmgs are prov bottom of each sleeve for bag installation and re- UNITED STATES PATENTS moval. Cleaned gas or air is discharged from an inter- 97l,390 9/1910 Matchette 55/366 mediate port in each sleeve, which p011 also is used 33 for the admission of reverse flow cleaning air or gas. 7 s 8 ar 3,541,764 11/1970 Astrom 55/341 10 Claims, 9 Drawing Figures PATENTEU P241974 swm 1 0r 3 SHEEI 2 BF 3 FIG. 6

FIG. 5

FIG. 7

PATNTED 3EP241974 SHEET 3 BF 3 9 2 3 a Q}: I z I f llqll H l w i. x 5 9 7 2 3 3 7 n a llll 4 m x m n FI4IIIIIH/XIE L l. 5 0 7 5 w 2 3 a 0 W FIG. 9

FIG. 8

BAGHOUSE DUST COLLECTOR THE INVENTION This invention relates generally to new and useful improvements in long tubular vertical fabric dust collectors of the types installed in mutiples in custom designed bag houses and particularly seeks to provide a novel bag and mounting therefor for top inlet operation that will enhance bag life and reduce down time during cleaning or replacement.

Baghouse dust collectors, as such, are well known and, regardless of whether or not they are designed for bottom inlet or top inlet operation, generally consist of multiple compartmented groups of vertically oriented fabric tubes or cylinders generally referred to as bags, each having a diameter on the order of one foot and a length on the order of 25-30 feet, with the flow of particulate-containing air or gas passing through the interiors so that a major portion of the solids carried thereby will collect on the inner walls for subsequent removal while a smaller portion thereof will drop into a receiver either for immediate or subsequent removal. Cleaning of the retained solids from the bags is effected at periodic intervals as by reverse flow, preferably by clean air or gas, with or without mechanical agitation of the bags to cause the loosened solids to drop into the receiver for removal.

It also is common for the bags to be supported between upper and lower tube sheets, with or without tension, in order to maintain the desired spaced parallel relationship therebetween.

Heretofore, all such bags for either bottom inlet or top inlet types of operations have been supported between the tube plates in such a manner that lateral deflection that may occur due to eddy currents within a given compartment can cause repeated contact between adjacent bags and rupture same, thus permitting a leakage of the uncleaned air or gas passing therethrough, or permitting a corresponding uncontained high velocity leakage of the uncleaned gas or air in the event that any one or more of the bags should develop punctures for any reason. In either event the resultant leakage from one bag may well cause corrsponding damage to an adjacent bag and this effect can progress through successively affected bags, thus not only reducing the efficiency ofthe baghouse but also requiring replacement of more than the single initially damaged bag.

In baghouses designed for bottom inlet operation the length (height) of the bags, having the standard diameter on the order of one foot, is practically limited to a maximum of about thirty feet, although a greater height would be desirable in order to increase the effective total filter area per bag. Top inlet operating baghouses need not be so limited as to the bag length, although heretofore with prior known types of such the physical or mechanical problems of controlling bag deflections during use or reverse flow cleaning thereof have acted as a deterrent.

However, a baghouse constructed in accordance with this invention, and particularly the means for mounting and supporting the individual bags overcomes the problems mentioned above, together with certain other problems that are inherent to the proper operation and maintainence of a baghouse, and provides a novel baghouse for top inlet type of operation.

Therefore, an object of this invention is to provide a novel bag assembly for installation in a baghouse designed for top inlet operations.

Another object of this invention is to provide a bag assembly of the character stated in which each bag is contained within an outer larger diameter rigid concentric sleeve that is open ended at its top and bottom and imperforate except for reclosable access openings adjacent the top and bottom of the contained bag and except for intermediate openings to provide for exhaust of the cleaned air or gas and for admittance of clean air or gas for reverse flow cleaning.

Another object of this invention is to provide a bag assembly of the character stated in which the top of the bag is removably affixed to an upper tube plate and in which the bottom of the bag is removably affixed to a thimble that is vertically slidable within the outer sleeve and constructed to prevent by pass of the uncleaned gas or air into the space between the interior of the sleeve and the exterior of the bag.

Another object of this invention is to provide a bag assembly of the character stated in which the bottom thimbles may be yieldingly biased downwardly in order to maintain the associated bags under axial tension.

A further object of this invention is to provide a bag assembly of the character stated in which the effect of the rupture or failure of any given bag will be confined within its own enclosing sleeve, thereby avoiding subsequent damage to any adjacent bags.

A further object of this invention is to provide a bag assembly of the character stated that provides for the more efficient use of an added chemical contactor such as limestone or sodium bicarbonate to control pollutants such as sulfur dioxide or sulfur trioxide.

A further object of this invention is to provide a top inlet bag assembly of the character stated in which the bag lengths may be substantially greater than the practical maximum possible for bottom inlet operation, thus providing more cloth area per unit of plan area.

A further object of this invention is to provide a bag assembly of the character stated that is simple in design, rugged in construction and economical to manufacture.

With these and other objects, the nature of which will become apparent, the invention will be more fully understood by reference to the drawings, the accompanying detailed description and the appended claims.

In the drawings:

FIG. 1 is a schematic horizontal section of a multibag module constructed in accordance with this invention and is taken along line 1-1 of FIG. 2;

FIG. 2 is a schematic vertical section taken along line 22 of FIG. 1;

FIG. 3 is an enlarged detail schematic vertical section of the upper end of a single bag assembly andd shows a preferred way of securing the upper end of the outer sleeve or shell to the plenum floor or upper tube sheet;

FIG. 4 is an enlarged detail schematic vertical section showing a preferred way of securing the lower endof the outer sleeve or shell to the lower tube sheet;

FIG. 5 is a view similar to FIG. 4 but additionally shows one means for providing a floating gastight connection between the bottom of the bag and its enclosing sleeve or shell; and

FIGS. 6 through 9 are views similar to FIG. 5 but showing a number of modifications for effecting the floating gastight connection between the bottom of the bag and its enclosing sleeve or shell.

Referring to the drawings in detail the invention, as illustrated is embodied in a multi-bag top inlet operating module for plural installations in a baghouse that includes the usual structural steel supporting frames 5, floor plates 6 for walkways, and external insulation 7.

Each module (see FIGS. 1 and 2) preferably comprises a plurality of pairs of symmetrically opposed bag assemblies generally indicated 8, 8 that are mounted beneath a common plenum or chamber 9 through which particulate-containing gas or air is admitted for subsequent passage through the bags for removal of the particulates. An inlet damper 10 is provided to control the flow rate into the plenum.

The floor of the plenum 9 is defined by an upper tube sheet 11 provided with a number of circular apertures for receiving and retaining the upper ends of the bag assemblies as will be hereinafter more fully described.

Each bag assembly 8 includes an outer rigid sleeve or shell 12 having its upper end (See FIG. 3) interlocked as at 13 to form a gastight filling around the edges of the associated aperture in the upper tube sheet 11 and terminating inwardly in a downwardly extending nipple or thimble l4 concentric therewith and having a terminal diameter such as to receive and retainthe upper cuffed end of a fabric dust bag 15 which is clamped thereto by a removable strap or collar 16.

The lower end of the shell 12 is provided with an outwardly extending bead 17 that is adapted to rest upon the upper surface of a bottom tube sheet 18, complementary to the tube sheet 10, for support thereby and gastight connection therewith as by either a continuous annular weld 19 as shown in FIG. 4 or by an annular seal 20 as shown in FIG. 5.

Since the bags 15 are of somewhat variable lengths when manufactured and also are subject to stretch and to thermal expansion and contractionin use, the lower ends thereof must be secured concentricably within the associated shells 12 through gastight connections that are self-adjusting in order to properly connect with bags of varying lengths either as initially installed or as changes in length may occur during use.

One such gastight connection is schematically shown in FIG. 5. Here, the lower end of the bag 15, which appears in dotted lines, is provided with the usual cuff 21 which is fitted over the open upper end of a cylindrical thimble 22, having an open bottom 23, and is secured thereto as by a clamp strap 24. A flexible tubular bellows 25 fits within the shell I2 externally of the thimble 22 and has its upper end secured to the shell by an internal expansion clamp 26 to effect a gastight connection to the shell. The bottom of the bellows 25 is firmly bonded or affixed to an outwardly extending annular flange 27 rigidly affixed to the thimble 22 adjacent the bottom thereof, thus providing a gastight connection between the bottom of the bellows and the thimble. If desired, annular or other suitable weights 28 may be inserted within the bellows 25 above the flange 27 to constantly urge the thimble 22 downwardly and thus apply tension to the bag 15.

Through the above described type of gastight connection, the thimble 22 readily may be raised or lowered to effect the initial connection with Iowerend of the bag at whatever height it may be within the limits permitted by the length of the bellows 25 and thereafter the thimble will become raised or lowered as operating conditions may cause changes in the length of the bag without affecting the integrity of the gastight connection. The flange 27, in addition to serving as an anchor for the bottom of the bellows 25, alsoserves to maintain the thimble 22 and the bag bottom concentric within the shell 12. t

The shells 12 of each module (see FIG. 2) open into a bottom hopper 29 which receives theparticulate matter removed from the air or gas being cleaned and is provided at its bottom with a suitable valve 30 for controlling continuous or intermittent discharge onto a takeaway conveyor (not shown). {The valve 30 also is used to apply suction to the interior whenever reverse flow cleaning is to be done.

In order to permit ready installation and removal of the bags 15, each of the shells 12 is provided with upper and lower access ports normally tightly covered by removable closure plates or

plugs

31, 31 respectively located adjacent the positions of the tops and bottomsof the bags. Each shell 12 is also provided intermediate its ends with an exhaust port 32 through which the cleaned air or gas is discharged. The exhaust ports 32 also serve as entrance ports for clean air or gas whenever the bags are to be cleaned by reverse cleaning to cause the filter cake accumulated on the inside thereof during normal use to be broken free for discharge into the hopper 29.

In operation, which generally occurs at a pressure differential between the inside of the bags 15 and the surrounding space within the shells 12 equivalent to a 2 to 10 inch columnof water, the air of gas to be cleaned is admitted to the tops of the bags, and passes downwardly and laterally therethrough. The heavier particulates will drop down directly into the hopper 29, while the lighter particulates will be drawn into contact with the inner bag walls as the cleaned air or gas passes therethrough and progressively form uniform filter cakes along the full lengths of the bags. These filter cakes are periodically removed, as mentioned above, by reverse flow cleaning with clean air or gas which generally comprises a recycled portion of the air or gas previously cleaned by the unit.

It should also be noted that since the shells 12 are per se rigid and also are rigidly connected to the supporting structure at their tops and bottoms, they become part of the supporting structure, thus enabling the elimination of certain partitions and other supporting structural elements that have heretofore been required.

Several modifications of the gastight connections between the bottoms of the bags 15 and the shells 12 may be resorted to in order that the free floating upward and downward movements of the bag bottoms will not be prevented due to abnormal conditions of operation or in order to prevent the thimble 22 from dropping downwardly to the full extension of the bellows 25 in the event of complete separation of the bags at or between their ends.

For example, and as shown in FIG. 6, the lower portion of the thimble 22 may be provided with a pair of vertically spaced

parallel flanges

33, 33 instead of the single flange 27 shown in FIG. 5, whereby to avoid canting of the thimble 22 during any upward or downward movement. Also, a plurality of inwardly directed abutments or stops 34 may be affixed to the inner wall of each sleeve 12 at a position lower than that of the lower limit of extension of the bellows 25 whereby to prevent the thimble from dropping down into the hopper 29 in the event of complete failure of the associated bag and consequent breakage of the bellows. Also, in this particular modification, the upper end of the bellows 25 may be attached to the depending rim of a permantly installed throat piece 35 affixed within the sleeve 12 and the lower end of the bellows may be clamped to the wall of the thimble 22 rather than being bonded to the upper surface of the associated outwardly extending flange. Insofar as the bellows 25 is concerned, it is believed that this arrangement is somewhat more practical than that shown in FIG. 5 since both ends can be secured by constricting clamp straps which are much easier to apply than the internally expanding top clamp 26 plus the externally constricting bottom clamp of that figure.

FIG. 7 shows a modification that may be used to facilitate introduction of the weights 28. Here, the bottom of the bellows 25 is clamped to the body of the thimble 22, rather than being bonded to the single flange 27, thus leaving a more clearly defined and free surface on the flange for support of the weights. Also, a ring abutment 35 may be used instead of the separate abutments 34 since it is simpler to install. Even so, the separate abutments 34 still may be preferable since they do not present as much exposed top surface areas upon which particulates can accumulate.

FIG. 8 shows a modification in which the bottom of the bag is attached to the top of the thimble 22 and the top of the bellows 25 is also attached to the thimble 22 adjacent the upper portion thereof while the bottom of the bellows is attached to an upstanding collar 36 integrally attached to a horizontal annulus 37 rigidly affixed to the sleeve 12. Radially extending supports 38 are provided for bag tensioning weights as desired or needed.

FIG. 9 is a modification similar to that shown in FIG. 8 except that tension springs 39 are interposed between the supports 38 and the annulus 37 in lieu of weights attached to the supports 38.

It is of course to be understood that variations in arrangements and proportions of parts may be made within the scope of the appended claims.

I claim:

1. In a dust collector designed for top inlet operation, a tubular vertical shell having a height substantially greater than its diameter; gastight means at the top of said shell for supporting therewithin the upper end of a concentrically disposed fabric tube maintained in spaced relation with respect to the interior wall of said shell; a pervious fabric tube having its upper end removably attached to said gastight supporting means and having a length for at least the major portion of the height of said shell; an open ended thimble, movably mounted, is carried within said shell for connection with the lower end of said fabric tube; means for removably connecting the lower end of said fabric tube to the upper end of said thimble; bellow means for effecting a flexible gastight connection between said thimble and said shell; means for maintaining said thimble in substantially spaced concentric relation with respect to said shell; said shell being provided intermediate its ends with at least one exhaust port whereby to permit discharge of particulate-free air or gas that has passed through the walls of said pervious fabric tube into the void defined by the outer wall of said tube, the inner wall of said shell and the said gastight supporting and connecting means adjacent the upper and lower ends of said shell.

2. The dust collector of claim 1 additionally including, means for causing admittance of particulatecontaining air of gas to the top of said fabric tube and passage therethrough for removal of the particulates, and means operably associated with the bottom of said shell and its contained fabric tube for receiving the removed particulates, either directly or as the result of reverse flow cleaning through said at least one exhaust port.

3. The dust collector of claim 1 in which said shell is provided with normally closed ports adjacent the upper and lower ends of said fabric tube for access thereto and with removable means for maintaining said ports in their normally closed states.

4. The dust collector of claim 3 in which there are a plurality of said vertical shells and their associated components arranged as a plurality of aligned symmetrically opposed pairs, in each pair of which said access and said exhaust ports extend in opposite directions.

5. The dust collector of claim 3 in which the said flexible bellow means for effecting said gastight connection between saidthimble and said shell comprises a tubular impervious bellows interposed therebetween and having one end securely fastened to the interior of said shell and its other end securely fastened to an annular surface of said thimble.

6. The dust collector of claim 5 in which said means for maintaining said thimble in spaced concentric relation with respect to said shell comprises an outwardly extending horizontal annular flange formed integrally with said thimble and having an outside diameter such as to be freely slidable vertically within said shell.

7. The dust collector of claim 5 in which said means for maintaining said thimble in space concentric relation with respect to said shell comprises a pair of vertically spaced outwardly extending horizontal annular flanges formed integrally with said thimble and having outside diameters such as to be freely slidable vertically within said shell.

8. The dust collector of claim 3 additionally including means for biasing said thimble downwardly whereby to apply axial tension to said fabric tube.

9. The dust collector of claim 8 in which said biasing means comprise weights supported by said thimble.

10. The dust collector of claim 8 in which said biasing means comprise springs interposed between said thimble and a lower portion of the interior wall of said shell.

Claims

2. The dust collector of claim 1 additionally including, means for causing admittance of particulate-containing air of gas to the top of said fabric tube and passage therethrough for removal of the particulates, and means operably associated with the bottom of said shell and its contained fabric tube for receiving the removed particulates, either directly or as the result of reverse flow cleaning through said at least one exhaust port.

5. The dust collector of claim 3 in which the said flexible bellow means for effecting said gastight connection between said thimble and said shell comprises a tubular impervious bellows interposed therebetween and having one end securely fastened to the interior of said shell and its other end securely fastened to an annular surface of said thimble.