Bag holder for self-cleaning bag filter

Disclosed is a clamping means for securing filter bags in a bag filter device. The bag filter device has a filter chamber separated from a plenum chamber by means of a partition having openings therein through which the filter bags extend from the plenum chamber into the filter chamber. Gas to be filtered is passed into the filter chamber and flows through the walls of the filter bags from the outside to the inside thereof and thence into the plenum chamber prior to being discharged from the filter device as cleaned gas. The partition has a stationary shoulder surrounding each opening on the plenum chamber side. The open end or cuff of each filter bag is clamped between the shoulder and a clamping ring so as to secure the filter bag in the partition and to effect a seal which prevents leakage of unfiltered gas into the plenum chamber from the filter chamber. The seal is maintained by the influence of gravity or by a seating or force-applying means. Each clamping ring also serves as a support for a bag supporting frame disposed in each filter bag.

BACKGROUND OF THE INVENTION 
This invention pertains to bag filter devices that are employed for 
separating entrained particulate solids from gases and, more particularly, 
pertains to means for clamping the cuffs of cloth or felt filter bags in 
bag filter devices of the type wherein the gas to be filtered is passed 
through the walls of filter bags from the outside to the inside, and 
wherein particulate solids which accumulate on the outside of the walls of 
the bags are periodically removed by back-pressuring to effect flow gas 
through the bag wall in a reverse direction, i.e. from the inside to the 
outside of the bags. 
Self-cleaning bag filter devices of the type just described are disclosed 
in U.S. Pat. Nos. 2,072,906; 3,377,783; 3,385,033; 3,550,359, and 
3,680,285. As can be seen from these patents, various means have been 
employed for securing the filter bags at the junction thereof with the 
partition between the plenum chamber and the filter chamber for the 
purpose of establishing and maintaining a seal whereby unfiltered gas is 
prevented from leaking from the filter chamber over into the plenum 
chamber wherein the cleaned gas is received from the bags, and whereby the 
established seal is also beneficial during back-pressuring of the bags to 
effect the removal of filtered solids therefrom. Although the bag clamping 
means shown in each of these patents can be utilized for securing the cuff 
of a filter bag to provide effective sealing, each of these means 
nonetheless has shortcomings with regard to construction cost and/or time 
and labor requirements for removing old bags and installing new ones. 
There was thus a continuing need for a bag clamping means for such filter 
bags whereby manufacture and use of such means was made simpler, easier 
and more economic. 
One object of the present invention is, therefore, to provide a bag 
clamping means which overcomes the aforesaid disadvantage of prior 
clamping means. 
Another object is to provide a bag clamping means of simple construction 
and low cost. 
Still another object is to provide an improved bag clamping means whereby 
filter bags can be more easily installed and removed from bag filter 
devices of the type which have previously been described, while 
nonetheless providing an effective seal for preventing leakage of 
unfiltered gas from the filter chamber of the bag filter devices into the 
plenum chamber thereof. 
Yet another object is to provide a bag clamping means having a simple and 
inexpensive hanger means in combination therewith for attaching a bag 
frame thereto. 
Still another object is to provide a bag filter device of the aforesaid 
type that is equipped with an improved clamping means for the filter bags 
contained therein. 
These and other objects and advantages of the present invention will become 
apparent from the following description and the appended claims. 
SUMMARY OF THE INVENTION 
The present invention is an improvement in bag clamping means used in a bag 
filter device having a filter chamber separated from a plenum chamber by a 
partition having a plenum chamber side, a filter chamber side, and at 
least one bag opening therein through which a filter bag extends from the 
plenum chamber into the filter chamber. 
In accordance with the present invention, a stationary shoulder on the 
partition and a movable clamping ring are located on the plenum side of 
the partition and both the clamping ring and the shoulder of the partition 
extend around the opening for the filter bag. The clamping ring is 
normally immobile and proximate the shoulder for clamping the walls of the 
bag between the two, the clamping ring being held in place with fasteners 
and/or resting in place by the influence of gravity or friction. The ring 
is nonetheless selectively movable with respect to the shoulder in order 
to effect a separation between the two for the purpose of changing a bag 
when it becomes worn, torn, irreversibly blinded, or needs to be removed 
for installation of another type of bag made of a different material or 
having a different porosity.

DESCRIPTION OF PREFERRED AND ALTERNATIVE EMBODIMENTS 
In FIG. 1, the bag filter device is generally depicted at 1 and comprises a 
filter chamber 2 and a plenum chamber 3. A partition 4 separates the two 
chambers, 2 and 3. The filter chamber is bounded by a metal wall 5 whereas 
the plenum chamber is bounded by a similar wall 6. The bottom of the 
filter chamber is in the form of a cone 7 which converges downwardly to an 
outlet 8 for discharge of solids that have been removed from the gas being 
cleaned by the filtration process. The outlet 8 is equipped with a rotary 
gas lock, represented at 9, which prevents excess leakage of unfiltered 
gas from the outlet. The filter chamber 2 has an inlet 10 for the gas to 
be cleaned, and a plurality of cloth or felt filter bags 11 are suspended 
from partition 4 and extend downwardly into the chamber. The plenum 
chamber 3 has an outlet 12 for filtered gas and a transition piece 13 
whereby the filtered gas is discharged from the filter device at a right 
angle to the vertical axis thereof through a cleaned-gas outlet 14. The 
entire filter chamber 1 is supported and stabilized by means of steel legs 
15. The partition is supported from below by means of one or more 
vertically extending plates 16, but the placement and dimensions of these 
support plates is such that the desired inflow and circulation of gas to 
be filtered is not hindered. The plenum chamber 3 is segmented by use of a 
plurality of vertically extending walls 17 therebetween to provide a 
series of cells which lead to the common central outlet 12. 
During operation of the bag filter device, a gas which contains an 
entrained particulate solid, e.g. air which contains a dust, is 
continuously fed into the filter chamber 2 through inlet 10. The gas then 
passes through the porous walls of the bags 11, from outside to inside, 
and thence out of the open outer ends thereof and into plenum chamber 3. 
Cleaned gas, having the solids removed therefrom by deposition of the 
solids on the walls of the bags, is discharged from the bag filter device 
through outlet 14. From time to time, a cleaning gas is injected into the 
plenum chamber 3 for a short duration in order to raise the pressure 
therein to a level in excess of that which exists in the filter chamber 2. 
This intermittent, momentary pressurization of the plenum chamber causes 
the bags 11 to flex outward and also causes the gas therein to flow in a 
reverse direction, i.e. from inside to outside of the bags, and deposited 
solids on the outside of bag walls are thus dislodged and thence drop into 
cone 7 for removal from the bag filter device through outlet 8 and air 
lock 9. 
As was previously indicated, the present invention pertains to a bag clamp 
which can be used to particular advantage with bag filter devices of the 
reverse flow type, one version of which has been described with reference 
to FIGS. 1 and 2. One embodiment of the present bag clamping means is 
shown in FIGS. 3-8. Referring to FIGS. 4, 5 and 6, the partition 4 of the 
bag filter device has a plenum chamber side 18, a filter chamber side 19, 
and an opening 20 therein through which bag 11 extends from the plenum 
chamber into the filter chamber. The bag has a closed inner end 22 and a 
cuff 21 at the open outer end thereof. The partition 4 has a stationary 
shoulder 23 thereon which is located on the plenum chamber side and which 
extends around opening 20 for the bag. As shown in FIGS. 3-8, the shoulder 
is a metal ring having a circular cross-section, but the cross-section can 
be semi-circular, square, rectangular, etc. Where preferred, that portion 
of the partition adjacent the hole 20 can be shaped to provide a shoulder, 
e.g. the edge of the hole can be curved or beveled, but it is preferred 
that the shoulder project outwardly from the partition as shown in the 
drawing in order to provide a top 38 and a side 39 (FIG. 4) over which the 
outer end, or cuff, of the bag can be folded. 
For use in conjunction with shoulder 23 for clamping a filter bag 11 at 
opening 20 to establish and maintain a seal between sides 18 and 19 of the 
partition by means of the bag, a movable clamping ring 24 also extends 
around opening 20 and is located on the plenum side 18 of the partition 
adjacent shoulder 23. Clamping ring 24 is normally immobile and proximate 
to the shoulder for clamping of the cuff 21 of the bag between the two, 
but the clamping ring is also selectively movable for separation thereof 
from the shoulder to permit changing of the bag. The clamping ring 24 can 
be emplaced by hand proximate the shoulder 23 for clamping of the cuff of 
the bag between the two and will remain in place and maintain a seal by 
the influence of gravity on the mass of the seal ring and any unsupported 
members attached thereto. 
Alternatively, the seal ring can be secured in place and/or tightened down 
by means of a seating or force-applying means (FIGS. 5 and 8) for aligning 
and, if desired, pushing against the clamping ring in a direction toward 
the shoulder, with the seating or force-applying means being releasable 
for separating the ring and shoulder during the changing of bags. As shown 
in the drawings, the seating or force-applying means for the clamp ring 
comprises seating members or threaded studs 25 which are located beyond 
the outer perimeter of the shoulder and the clamp ring and which are 
stationarily anchored to partition 4. The studs 25 project axially with 
respect to the shoulder and the clamp ring, and seating devices or lugs 26 
which project outwardly from and are connected to the clamp ring have 
openings 27 therein through which the studs 25 pass upwardly. When nuts 28 
are tightened they bring force to bear on the lugs, with clamping ring 24 
thus being urged toward shoulder 23 for firm clamping of the bag cuff 21. 
When the bag is to be changed, the nuts 28 are removed from studs 25 so 
that the clamping ring can be lifted off the shoulder and to one side of 
opening 20. Other force-applying means for the clamping ring can also be 
used, e.g. the ring can be hinged at the edge for upward and downward 
pivoting with respect to the shoulder, and with one lug and one stud being 
located opposite the hinge for forcing the clamping ring toward the 
shoulder. Even other types of force-applying means can be used where 
preferable and practical. 
As shown in FIGS. 3-8, the clamping ring 24 also serves as a support for a 
bag frame, generally represented at 29, for maintaining bag 11 in an 
uncollapsed state during the filtering of gas. Accordingly, the clamping 
ring can be equipped with an attached hanger member 30 which extends 
across the central opening in the ring, and the hanger member can be 
adapted for attachment of the filter-bag frame thereto. More specifically, 
the hanger member is adapted for attachment thereto of a disengaged 
connector, in this example a hook 31, on the upper end of a bag frame 29 
that is suspended from the hanger. 
Advantageously, the hanger member 30 can be in the form of a rigid bar 
adapted for placement of hook 31 over the top of the bar as shown. In the 
drawings, the rigid-bar hanger member 30 extends all the way across the 
opening of the ring, but it will be understood that it can extend only 
part way across and still be adapted to function effectively as a hanger 
member. Alternatively, other hanger means can be employed for suspension 
of the bag frame, and means other than a hook may be employed for 
connecting the hanger and the frame. Whereas the illustrated bag frame has 
U-shaped longitudinally extending tubular members 32 for maintaining the 
bag in an uncollapsed state, cross-braces 33 for stabilizing the U-shaped 
pieces, and a hook 31 attached to an upper crossbrace of the bag frame, it 
will nonetheless be appreciated that other types of bag frames can be 
suspended from the hanger, and that a hook, when used, can be attached to 
other parts of the bag frame. 
Preferred embodiments of the invention involve use of a bag hanger member 
in combination with force-applying means for the clamping ring as is 
illustrated in the drawings. Referring to FIG. 5, for example, it can be 
seen that the hanger bar 30 not only extends all the way across the 
opening of the attached clamping ring but also has ends 30a and 30b that 
extend beyond the outer periphery of the ring and which have openings 27 
therein which extend axially with respect to the ring. In this case the 
lugs 26 are a part of the hanger member, and threaded studs 25, which are 
anchored to the partition 4, extend through openings 27 axially with 
respect to clamping ring 24, and the ring is thus urged toward shoulder 23 
for clamping of the cuff 21 when nuts 28 are tightened. 
The installation and clamping of a filter bag by means of the present 
apparatus can best be visualized by reference to FIG. 7. The bag 11 is 
first slipped over frame 29 and the cuff 21 is turned outward for 
engagement with shoulder 23 on partition 4. The hook 31 is then engaged, 
as shown, with the hanger bar 30. Clamping ring 24 is attached to the 
hanger bar, and the bar thus serves as a handle. The bag frame 29 with the 
bag thereon having a transverse dimension less than the opening 20 (see 
FIG. 5), is easily maneuvered into opening 20 and lowered into the filter 
chamber until the bag cuff abuts shoulder 23 and the clamping ring 24 
comes to rest on the bag cuff. The clamping ring can then be pushed down 
with the force-applying means, as previously described, for secure 
gripping of the bag cuff. FIGS. 3, 4, 5, 6 and 8 represent the 
relationship of the apparatus combination after seating of the bag cuff 
with the shoulder 23 and the clamping ring 24. In FIGS. 5 and 6 it can be 
seen that leakage of unfiltered gas from the filter chamber side to the 
plenum chamber side of the partition is prevented by a braze 34 (FIG. 6) 
between the partition and ring 23, and by the wall of the bag 11. Provided 
ring 24 is forced down tight enough, leakage of unfiltered gas through the 
gap between the ring and shoulder 23 is prevented by the presence of bag 
cuff 21 between the two. The seal effected by means of the shoulder, 
clamping ring and bag cuff is also effective and hence beneficial during 
back pressuring of the bags. 
By further reference to FIGS. 3-8 it can be seen that the shoulder 23 and 
the clamping ring 24 each han an uninterrupted, bag gripping face therein, 
represented at 35 and 36 respectively, and that these faces oppose each 
other, with the gripping face of the shoulder being aligned for abutment 
with the outer side of the bag cuff 21 whereas the gripping face on the 
clamping ring is aligned for abutment with the inner side of the cuff. As 
shown in FIGS. 3-8, the gripping face 36 of the clamping ring is on the 
bottom thereof while the gripping face 35 of the shoulder is on the top 
thereof. However, by reference to FIGS. 9 and 10, it can be seen that in 
other embodiments of the present invention the clamping ring 24a or 24b 
can be adjacent to the side of the shoulder 23a or 23b when the cuff 21 of 
a bag is clamped between the ring and the shoulder, this being in 
distinction to the clamping ring being adjacent to the top of the shoulder 
as shown in FIGS. 3-8. In addition, the bag gripping faces 35a and 35b on 
shoulders 23a and 23b, respectively, in FIGS. 9 and 10 are on the outside 
of the shoulder, and with gripping faces 36a and 36b on clamping rings 24a 
and 24b being on the inside thereof. Accordingly, when the clamping ring 
is adjacent to the side of the shoulder as shown in FIGS. 9 and 10, the 
gripping faces on the sides of these members are opposed to each other for 
very secure gripping of the bag cuff 21 which can be folded back over the 
shoulder for more effective frictional contact therewith. As shown in FIG. 
11, the ring 24a (or 24b) can be split into clamping ring halves from the 
inside to the outside of the ring as represented at 37, to permit outward 
flexing thereof during emplacement of the ring around the shoulder, but 
whereafter the ring nonetheless exerts satisfactory inward pressure toward 
the shoulder and against the bag cuff. 
Gripping faces 35, 35a, 36 and 36a are curved, but the faces can also be 
flat as in FIG. 10. In addition, flat faces can be used, where preferred, 
as substitutes for the curved faces shown for ring 24 and shoulder 23 in 
FIGS. 3-8. It will also be understood that even though the shoulder and 
clamping ring are shown having a circular configuration when viewed 
axially, the configuration of these members when thus viewed can also be 
square, rectangular, elliptical, etc., according to the configuration of 
the cross-section of the bag being used. 
The bag filter device of FIGS. 1 and 2 has a plurality of filter bags 11, 
openings 20 in the partition 4, and bag clamping means as shown in FIGS. 
3-8. For inspection and/or replacement of filter bags, the plenum chamber 
enclosure 6 and transition piece 13 are lifted off of the filter chamber 
or otherwise opened to provide suitable access to the bag clamping means. 
Following removal of nuts 28, if used, a bag and its frame can be removed 
through opening 20 by merely lifting by hand as shown in FIG. 7. The old 
bag can then be removed from frame 29 and a new one placed on the frame 
for simple reinsertion into the bag opening in the partition. Once the bag 
cuff has been gripped between the shoulder and the ring, nuts 28, if used, 
are retightened. Where desired, as will be apparent from a study of FIGS. 
5 and 7, the bag 11 and frame 29 may be withdrawn downwardly through the 
partition opening 20 by disengagement of the hook 31 from the hanger bar 
30 and lowering of the frame 29 and bag 11 into the filter chamber 2. In 
most installations gravity alone is sufficient to maintain a satisfactory 
seal and cause the structure to stay in place. It should be noted from 
FIGS. 9 and 10, for instance, that the bag cuff 21 folds over the shoulder 
and then under the clamping ring whereby gripping of the bag cuff occurs 
not only between the gripping faces of these two members but also between 
the bottom of the clamping ring and the plenum chamber side 18 of the 
partition 4, thus providing a double grip and seal effect. 
The present invention provides certain advantages not made available from 
prior bag clamping apparatus as disclosed for instance in U.S. Pat. Nos. 
3,505,359 to Fisher et al and 2,072,906 to Rosenberger. By means of the 
present apparatus there is no need for a steel ring to be sewn into the 
cuff of the bag, as disclosed by Fisher et al, for attempting to secure 
the bag and establish a seal at the partition between the plenum chamber 
and the filter chamber. Neither is there any need for a separate clip, as 
disclosed by Rosenberger, to hold a bag cuff in sealing engagement with a 
sleeve on a bag frame and the shoulder of a force-applying plate, for it 
will be appreciated that the present clamping mean is not dependent upon 
the presence of a bag frame. 
A bag clamping means and a bag filter device which fulfill the aforestated 
objects has now been disclosed in detail, and even though the invention 
has been described with reference to particular apparatus, apparatus 
combinations, materials of construction, configuration, orientations, and 
the like, it will nonetheless be understood that even other embodiments 
will become apparent which fall within the spirit and scope of the 
invention defined in the following claims.