Two element filter bag

My invention comprises a two element filter bag which includes a cylindrical outer element, a generally tubular inner element, a joining means, a securing means, and a diverting means. Cylindrical outer element is hollow, constructed of suitable filter media, and has first and second open ends. Tubular inner element is also hollow, constructed of suitable filter media, and has one closed end and one open end. Tubular inner element is positioned within cylindrical outer element so that the first open end of the outer element is generally coplanar with the closed end of the inner element, and the second open end of the outer element is generally coplanar with the open end of the inner element. Joining means joins the second open end of the outer element to the open end of the inner element. Supporting means is positioned within the inner element through open inner element end and provides support to inner element. Diverting means uniformly diverts the process flow entering the filter bag through first open outer element end throughout the interior of the filter bag. Preferably, diverting means comprises a cone shaped inner element closed end. Process flow is filtered by the filter bag when the flow collides with and permeates through the inside surface of the outer element and the outside surface of the inner element.

BACKGROUND OF THE INVENTION 
1. Field of Invention 
This invention relates to filtration systems which separate solids from 
liquids in process flows. More specifically, this invention is an 
improved, low-cost filter bag used to remove solids from industrial 
process flows. 
The invention includes a greater amount of filter media surface area than 
comparably sized prior art filter bags, provides the additional surface 
area without a corresponding restriction in flow, includes a means by 
which the growth of the layer of solids retained within the filter bag is 
uniform throughout the length of the filter bag, and is capable, without 
collapsing upon itself, of being cleaned by reversing the direction of the 
process flow. The invention may be utilized in a variety of chemical 
and/or industrial process flow applications requiring filtration as long 
as the filter bag is constructed from the appropriate filter media for 
each flow. 
Generally, filter bags are used in industrial process flows to separate 
solids from liquids. Being permeable only to particles which are smaller 
than a pre-determined, specific size, the filter bag retains any solid 
particles in the process flow which are larger than the specific size. On 
the other hand, any particles which are the specific size or smaller 
(usually only liquid particles) permeate through the filter bag and 
continue in the flow. The micron rating of the filter media from which the 
filter bag is constructed dictates the particle sizes which will be 
retained by the filter bag and which will permeate through the bag. 
During the life of the filter bag, as more solids accumulate, a layer of 
solids is formed within the filter bag. As the layer becomes thicker, the 
layer of solids becomes a substantial restriction to the flow of process 
through the filter bag, and the filter bag must then be replaced or 
cleaned (hereinafter referred to as the "critical thickness"). 
It is axiomatic that an increase in the size or surface area of the filter 
bag provides a corresponding increase in the quantity of solids retained 
by the filter bag. In addition, an increase in the surface area of the 
filter bag also increases the usable life of the filter bag by prolonging 
the time it takes the filter bag to reach the critical thickness of 
solids. Thus, it is advantageous to maximize the surface area of the 
filter bag. 
However, several limitations exist in maximizing the amount of surface area 
of a filter bag. First, in order to be used in most, if not all, of the 
existing process flow equipment and systems, a filter bag must have a 
specific shape and certain dimensions. Second, as surface area is added to 
the filter bag (by way of folds or layers to the filter bag), the 
additional surface area itself tends to act as a restriction to the flow 
by providing too many obstructions within the filter bag. 
The key then is to maximize the filter media surface area without 
restricting the flow of process through the filter bag. It would thus be 
advantageous to construct a filter bag which maximizes the filter media 
surface area without restricting the flow of process through the filter 
bag. 
Another problem inherent in prior art filter bags is that the layer of 
solids heretofore described tends to concentrate in only one section of 
the prior art bags. For instance, in the standard type of tubular shaped 
filter bag, the process flow enters the bag through the bag's open end and 
exits the bag through the bag's closed end. The great majority of the 
process flow exits the bag and is filtered by the bag's closed end. 
Naturally, the layer of solids builds up primarily at the bag's closed 
end. Since the layer of solid accumulates and grows primarily at one 
section of the filter bag, the layer grows quickly and reaches the 
critical thickness of solids much more rapidly than if the layer of solids 
builds up uniformly throughout the length of the filter bag. It would thus 
be advantageous to design a filter bag in which the growth of the layer of 
solids is uniform throughout the length of the filter bag thereby 
extending the time for the formation of the critical thickness of solids. 
In addition, the majority of prior art filter bags can be cleaned only by 
removing the bags from the process flow equipment and system. Although 
this cleaning method is prevalent in the field of art, the method can be 
improved since it ordinarily requires a shut down of the process flow 
thereby resulting in time and monetary loss to the operator of the 
facility. It would thus be advantageous to devise a filter bag (and 
method) which can be cleaned without the need to remove the filter bag 
from the process flow equipment and system. 
A technique sometimes used to clean filter bags which does not require 
their removal from the process equipment and system is a "backwash 
operation." During the backwash operation, the process flow is reversed 
through the filter bag and the solids retained within the filter bag 
during normal operation are thereby dislodged. This technique, however, is 
not widely used since, among other reasons, prior art filter bags 
constructed of flexible filter media tend to collapse once the backwash 
operation is in effect. It would thus be advantageous to construct a 
filter bag made of flexible filter media which may be cleaned by a 
backwash operation and does not collapse during the backwash operation. 
2. Related Art 
Filter bags and other such filtration mechanisms have long been known to 
the prior art. Illustrative of such devices are U.S. Pat. No. 2,278,603 
issued to Williams in 1942, U.S. Pat. No. 2,314,640 issued to Winslow et 
al. in 1943, U.S. Pat. No. 2,539,768 issued to Anderson in 1951, U.S. Pat. 
No. 2,613,814 issued to Moore in 1952, U.S. Pat. No. 2,946,449 issued to 
Shaw in 1960, U.S. Pat. No. 4,056,374 issued to Hixenbaugh in 1977, U.S. 
Pat. No. 4,231,770 issued to Johnson, Jr. in 1980, U.S. Pat. No. 4,280,826 
issued to Johnson, Jr. in 1981, U.S. Pat. No. 4,297,115 issued to Johnson, 
Jr. in 1981, U.S. Pat. No. 4,304,580 issued to Gehl et al. in 1981, and 
U.S. Pat. No. 4,324,571 issued to Johnson, Jr. in 1982. 
U.S. Pat. No. 2,278,603 issued to Williams discloses a filter which is at 
least partially cylindrical in shape. For the purpose of increasing the 
filter media surface area, the cylindrically shaped filter includes 
inwardly projecting folds. The inner edges of the folds define the outline 
of a cone and the depth of the folds increases progressively upwardly. 
However, the Williams Patent does not disclose, among others, a means by 
which the growth of the layer of solids within the filter is uniform 
throughout its length. 
The Hixenbaugh Patent discloses a tubular gas filter bag; however, the 
Hixenbaugh bag does not include, among others, additional filter media 
surface area (as compared against similarly sized filter bags) or a means 
by which the growth of the layer of solids within the filter is uniform 
throughout its length. 
Lastly, the family of Johnson, Jr. Patents all disclose a bag type gas 
filter with at least one supporting structure located within the bag. The 
supporting structures permit the bags to be cleaned by reversing flow 
through the filter media. However, the Johnson, Jr. inventions do not 
include, among others, additional filter media surface area (as compared 
against similarly sized filter bags). 
Though the above mentioned inventions may be helpful for their stated 
purpose, they can be improved to provide a filter bag for industrial 
process flows which includes a greater amount of filter media surface area 
than comparably sized prior art filter bags, includes the additional 
surface area without a corresponding restriction in the flow, includes a 
means by which the growth of the layer of solids retained within the 
filter bag is uniform throughout the length of the filter bag, and is 
capable, without collapsing upon itself, of being cleaned by reversing the 
direction of the process flow. 
SUMMARY OF THE INVENTION 
Accordingly, the objectives of this invention are to provide, inter alia, a 
filter bag that: 
possesses a greater amount of filter media surface area than comparably 
sized prior art filter bags; 
includes the additional filter media surface area without a corresponding 
restriction in the process flow; 
includes a means by which the growth of the layer of solids within the 
filter bag is uniform throughout the length of the filter bag; 
can be cleaned without having to be removed from the process flow filtering 
equipment and system; and 
can be cleaned, without collapsing upon itself, by reversing the direction 
of the process flow. 
Other objects of the invention will become apparent from time to time 
throughout the specification and claims as hereinafter related. 
To achieve such improvements, my invention comprises a two element filter 
bag which includes a cylindrical outer element, a generally tubular inner 
element, a joining means, a securing means, and a diverting means. 
Cylindrical outer element is hollow, constructed of suitable filter media, 
and has a first and a second open end. Tubular inner element is also 
hollow, constructed of suitable filter media, and has one closed end and 
one open end. Tubular inner element is positioned within cylindrical outer 
element so that the first open end of the outer element is generally 
coplanar with the closed end of the inner element, and the second open end 
of the outer element is generally coplanar with the open end of the inner 
element. Joining means joins the second open end of the outer element to 
the open end of the inner element. Supporting means is positioned within 
the inner element through open inner element end and provides support to 
inner element. Diverting means uniformly diverts the process flow entering 
the filter bag through first open outer element end throughout the 
interior of the filter bag. Preferably, diverting means comprises a cone 
shaped inner element closed end. Process flow is filtered by the filter 
bag when the flow collides with and permeates through the inside surface 
of the outer element and the outside surface of the inner element.

DETAILED DESCRIPTION OF THE INVENTION 
My invention is illustrated in FIGS. 1 through 13 and the two element 
filter bag is depicted as 10. 
Generally, as shown in FIG. 1, filter bag 10 is positioned in a filter 
vessel 200 commonly known in the field of art. Filter vessel 200 includes 
a filter vessel lid 202 and a filter vessel container 204. Filter vessel 
lid 202 includes a process flow inlet 206. Filter vessel container 204 is 
hollow thereby defining a container inner cavity 205. Filter vessel 
container 204 includes a container top surface 209, a container top 
opening 213, and a container bottom 208 having a process flow outlet 210. 
Filter vessel lid 202 is sealingly attached to filter vessel container 204 
by way of lid attachment means 212. Preferably, lid attachment means 212 
comprises a bolt, nut, and seal mechanism (not shown but commonly known in 
the prior art) adequate to provide a seal between filter vessel lid 202 
and filter vessel container 204. 
Container top surface 209 also includes a container top surface lip 211 
which extends into and defines container top opening 213, making container 
top opening 213 circular in shape. Circular container top opening 213 is 
generally concentric with filter vessel container 204. Furthermore, 
container top surface lip 211 includes a container top surface groove 214 
which lines the circumference of circular container top opening 213. 
A basket 220, which is preferably generally cylindrical in shape, is 
slidably insertable and positioned within filter vessel container 204 
through container top opening 213. Thus, in order to fit through container 
top opening 213, the diameter of the cross-section of basket 220 is 
slightly smaller than the diameter of container top opening 213. Basket 
220 is rigid, and is constructed of a permeable material, such as 
perforated stainless steel, carbon steel, or polypropylene. The selection 
of the material from which the basket 220 is constructed depends, among 
other things, on the chemistry (ie. acidity) and density of the process 
flow. 
Basket 220 comprises a basket wall 224 and a basket bottom 225. Basket 220 
further comprises a basket lip 226 extending radially outward from the end 
of basket 220 distal basket bottom 225. Basket lip 226 is sized and 
constructed so that it securely fits onto container top surface groove 
214. Thus, basket 220 is suspended within filter vessel container 204 from 
container top surface groove 214 and may be selectively slidably 
insertable into and positioned within filter vessel container 204. 
Filter vessel 200 may further include a basket alignment means 222 to 
ensure the proper alignment of basket 220 within filter vessel container 
204. Preferably, basket alignment means 222 comprises at least one bracket 
223 permanently attached to the container interior wall 207. The brackets 
223 are sized and constructed to abut basket wall 224 when basket 220 is 
positioned within filter vessel container 204. As basket 220 is inserted 
into filter vessel container 204 through container top opening 213, 
brackets 223 serve to align and maintain basket 220 in its generally 
concentric position. 
Filter bag 10 is positioned within and supported by basket 220. Generally, 
when basket 220 is positioned within filter vessel container 204 (ie. when 
basket lip 211 is situated on container top surface groove 214), one end 
of filter bag 10 is suspended from the upperside of basket lip 226 with 
the remainder of the filter bag 10 falling into and being supported by 
basket 220. Thus, since filter bag 10 encircles the entire container top 
opening 213, all process flow entering filter vessel 200 must pass through 
circular top opening 213 and filter bag 10 in order to exit filter vessel 
200. 
As best shown in FIGS. 1-5, filter bag 10 generally comprises an outer 
element 20, an inner element 30, supporting means 40, joining means 50, 
and diverting means 100. 
Outer element 20 is constructed of filter media suitable to filter the 
contents of the process flow in which the filter bag 10 is used. Suitable 
filter media include composite textile liquid filter media, such as 100% 
spun polypropylene or polyester, rated at one of a range of microns. The 
media is normally composed of three layers, an outer layer and inner layer 
with spun bonded non woven fabric and one central layer with melt blown 
non woven fabric. Preferably, the micron rating of the filter media is 
absolute (rated at 99% efficiency) as opposed to nominal (rated at less 
than 99% efficiency). However, the appropriate type of filter media and 
micron rating used on the filter bag 10 will depend on the application of 
the filter bag 10 and the contents of the process flow in which the filter 
bag 10 is used. It is understood that the scope of this invention also 
encompasses non-textile and rigid filter media. Preferably, however, the 
filter media used is flexible and resilient. Outer element 20 is 
preferably cylindrical in shape and is hollow. Outer element 20 includes 
an outer element first end 21, an outer element second end 22, an outer 
element outside surface 29, and an outer element inside surface 28. Outer 
element first and second ends, 21 and 22, are open. Preferably, outer 
element 20 is constructed of a single piece of filter media which is sewn 
together (not shown) into the hollow, cylindrical shape shown in the 
Figures and described herein. 
In order to be utilized within filter vessel 200, the dimensions of outer 
element 20 are sized so that filter bag 10 may be suspended from basket 
lip 226 (as previously disclosed) at one end with the remainder of the 
filter bag 10 falling into and being supported by basket 220. Thus, the 
cross-sectional diameter of outer element 20 is preferably slightly 
smaller than both the cross-sectional diameter of basket 220 and the 
diameter of container top opening 213 (which is defined by container top 
surface lip 211). Furthermore, the length of outer element 20 is 
preferably slightly smaller than the length of basket 220. Therefore, when 
filter bag 10 is suspended from basket lip 226 and is in place within 
basket 220, basket wall 224 substantially abuts outer element outside 
surface 29, and basket bottom 225 substantially abuts outer element second 
end 22. Of course, the dimensions of the filter bag 10 will vary depending 
on the dimensions of the filter vessel 200 and the filter vessel basket 
220 utilized in the process flow. 
Outer element 20 also preferably includes a shaping means 25 which provides 
and maintains the cylindrical shape of outer element's 20 flexible filter 
media (in the preferred embodiment) In order to provide and maintain such 
shape, shaping means 25 is constructed of a rigid material such as 
stainless steel, carbon steel, or polypropylene. The selection of the 
material from which the shaping means 25 is constructed depends, among 
other things, on the chemistry (ie. acidity) and density of the process 
flow. Shaping means 25 is preferably sized and constructed so that it may 
rest on the basket lip 226 of filter vessel 200 thereby suspending the 
filter bag 10 from the basket lip 226 and into basket 200. 
As best shown in FIGS. 4-7, connecting means 27 connects shaping means 25 
to outer element 20. Preferably, connecting means 27 connects shaping 
means 25 to outer element 20 near outer element first end 21. Connecting 
means 27 comprises any suitable means for connecting filter media to the 
rigid shaping means 25. In the preferred embodiment, connecting means 27 
comprises sewing a portion of outer element first end 21 around or to 
shaping means 25. Connecting means 27 may also comprise heat sealing a 
portion of outer element first end 21 around or to shaping means 25. 
In a preferred embodiment, shaping means 25 comprises a ring 26 having a 
generally circular cross-section. In order for ring 26 to rest on basket 
lip 226, the outer diameter of ring 26 must be at least slightly larger 
than the cross-sectional diameter of basket 220 (and necessarily the 
cross-sectional diameter of outer element 20). Thus, ring 26 rests on 
basket lip 226 suspending filter bag 10 into basket 220. 
In another preferred embodiment, as shown in FIGS. 7 and 8, shaping means 
25 comprises an annular flange 150 having an L-shaped cross-section with 
the flange section 151 of annular flange 150 extending radially outward 
from annular section 152. In order for the flange section 151 of annular 
flange 150 to be able to rest on basket lip 226, the outer diameter of 
annular section 152 must be at least slightly smaller than the 
cross-sectional diameter of basket 220 and the outer diameter of flange 
section 151 must be at least slightly larger than the cross-sectional 
diameter of basket 220 (and necessarily the cross-sectional diameter of 
outer element 20). Thus, flange section 151 (and annular flange 150) rests 
on basket lip 226 suspending filter bag 10 into basket 220. 
As shown in FIG. 6, in the embodiment including ring 26, connecting means 
27 comprises sewing (or heat sealing) the outer element first end 21 
around ring 26. As shown in FIG. 7, in the embodiment including annular 
flange 150, connecting means 27 comprises sewing (or heat sealing) the 
outer element first end 21 to the annular section 152 of annular flange 
150. 
Inner element 30 is constructed of suitable filter media. The types of 
filter media suitable for inner element 20 are the same as those suitable 
and described previously for outer element 20. Although not a requirement, 
inner element 30 is preferably constructed of the same type of filter 
media as outer element 30. 
As best shown in FIGS. 1-5, inner element 30 is generally tubular in shape 
and hollow. In addition, inner element 30 includes an inner element first 
end 31, an inner element second end 32, an inner element outside surface 
38, and an inner element inside surface 39. Inner element second end 32 is 
open, and inner element first end 31 is closed. 
Inner element 30 is sized to be located and fit within the cylindrically 
shaped outer element 20. Thus, outer element inside surface 28 is adjacent 
inner element outside surface 38. In addition, the cross-section of inner 
element 30 at inner element second end 32 is preferably substantially 
coplanar with the cross-section of outer element 20 at outer element 
second end 22. Thus, inner element second end 32 is proximate to outer 
element second end 22. Likewise, the cross-section of inner element first 
end 31 is preferably coplanar with the cross-section of outer element 
first end 21. Thus, inner element first end 31 is proximate to outer 
element first end 21. 
Preferably, inner element 30 and outer element 20 are constructed of a 
single piece of flexible and resilient filter media which is sewn (or heat 
sealed) together into the overall shape of the invention shown in the 
Figures and described herein. The shape of the unsewn integral piece of 
flexible filter media is shown in FIG. 9. 
As shown in FIGS. 4 and 5, in the preferred embodiment, the generally 
tubular shape of inner element 30 can be more specifically described by 
dividing inner element 30 into three sections: inner element first section 
34, inner element second section 35, and inner element third section 36. 
Inner element first section 34 includes open inner element second end 32. 
Inner element third section 36 includes closed inner element first end 31. 
Inner element second section 35 is located intermediate inner element 
first section 34 and inner element third section 36. Each section, 34, 35, 
and 36, has a slightly different shape. As shown in the Figures, inner 
element second section 35 constitutes the majority of inner element 30. 
In the embodiment as shown in FIG. 5, the shape of inner element first 
section 34 is generally frustoconical with the cross-sectional diameter of 
section 34 decreasing from inner element second end 32 towards the 
junction between inner element first section 34 and inner element second 
section 35. Preferably, at inner element second end 32, the 
cross-sectional diameter of inner element first section 34 is 
substantially equal to the cross-sectional diameter of outer element 
second end 22. 
In another embodiment as shown in FIG. 4, the shape of inner element first 
section 34 is a truncated section generally conical in shape, but having 
one of its vertical portions parallel to and continuing the shape of 
cylindrical inner element second section 35 (as will be disclosed herein). 
In this embodiment, the cross-sectional diameter of section 34 also 
decreases from inner element second end 32 towards the junction between 
inner element first section 34 and inner element second section 35. Also 
preferably, at inner element second end 32, the cross-sectional diameter 
of inner element first section 34 is substantially equal to the 
cross-sectional diameter of outer element second end 22. 
Inner element second section 35 is cylindrical in shape. Thus, the 
cross-sectional diameter of inner element second section 35 is constant 
from its junction with inner element first section 34 to its junction with 
inner element third section 36. 
Inner element third section 36 is generally conical in shape. The 
cross-sectional diameter of inner element third section 36 decreases in 
the direction distal to inner element second section 35 and towards the 
nose 37 of the conical shape. It should be noted that the nose 37 of inner 
element third section 36 coincides with inner element first end 31. 
In another embodiment of inner element 30 (not shown), the entire inner 
element 30 is constructed in the shape of a cone. In this embodiment, the 
cross-sectional diameter of inner element 30 decreases from the inner 
element second end 32 towards the nose 37 (which coincides with inner 
element first end 31) of the conical shape. 
As previously disclosed herein, one of the key objectives in filter bag 
design is to maximize the amount of filter media surface area which comes 
into contact with the process flow without restricting the flow of process 
through the filter bag 10. Thus, as a general requirement, the relative 
dimensions of outer element 20 to inner element 30 should be optimized to 
accomplish such objective. After substantial experimentation by the 
Applicant, it has been found that the optimum relative dimensions of outer 
and inner elements, 20 and 30, are as follows: 
1! the cross-sectional diameter of outer element 20 should be in the range 
of 1.50 to 2.00 times as large as the cross-sectional diameter of inner 
element second section 35; and 
2! the length of outer element 20 should be in the range of 1.10 to 1.30 
times as long as the aggregate length of inner element second section 35 
and inner element first section 34. 
Preferably, the cross-sectional diameter of outer element 20 is 1.75 times 
as large as the cross-sectional diameter of inner element second section 
35. Also preferably, the length of outer element 20 is 1.20 times as long 
as the aggregate length of inner element second section 35 and inner 
element first section 34. In any respect, the relative lengths of the 
cross-sectional diameter of outer element 20 to the cross-sectional 
diameter of inner element second section 35 and the relative length of 
outer element 20 to the aggregate length of inner element second section 
35 and inner element first section 34 must be such that an annular 
retention volume is defined between inner element 30 and outer element 20. 
The remainder of the relative dimensions of the filter bag 10 necessarily 
follow from the disclosure limitations described herein. 
Filter bag 10 also preferably includes a diverting means 100. Diverting 
means 100 must be located within the cylinder of outer element 20 and is 
preferably located proximal outer element first end 21 (the filter bag 10 
inlet of the process flow). Diverting means 100 diverts the process flow 
around inner element outside surface 38 and within outer element inside 
surface 28. In this way, diverting means 100 disperses the flow uniformly 
throughout the filter media and along the entire length of the inner 
element outside surface 38 and the outer element inside surface 28. 
In the preferred embodiment, diverting means 100 comprises the conically 
shaped inner element third section 36. In the embodiment in which the 
entire inner element is conical in shape (not shown), diverting means 100 
comprises the nose 37 of the conical shape (which coincides with the inner 
element first end). 
Joining means 50 sealingly joins inner element 30 to outer element 20. In 
the preferred embodiment, the second end 22 of outer element 20 is 
sealingly joined to the second end 32 of inner element 30. Preferably, as 
previously disclosed herein, outer element 20 and inner element 30 are 
constructed of one integral piece of flexible filter media. The integral 
filter media piece is sewn together into the shape shown in the Figures 
and described herein. In this preferred embodiment, joining means 50 
comprises a fold 80 in the integral piece of filter media between outer 
element second end 22 and inner element second end 32. 
In another embodiment in which outer element 20 is a separate piece from 
inner element 30 (not shown in the Figures), joining means 50 comprises 
joining the second end 22 of outer element 20 to the second end 32 of 
inner element 30 by sewing or heat sealing. In yet another embodiment (not 
shown in the Figures), joining means 50 comprises joining both the second 
end 22 of outer element 20 and the second end 32 of inner element 30 to a 
separate and independent annular structure by either sewing or heat 
sealing. 
Supporting means 40 is positioned within and provides support to inner 
element 30. Supporting means 40 must be sufficiently rigid to support and 
maintain the structure of inner element 30 and must be sufficiently 
permeable to allow filtrated process flow therethrough. Supporting means 
40 is preferably constructed of a rigid material with perforations or 
holes therein, such as perforated stainless steel, carbon steel, or 
polypropylene. The selection of the material from which supporting means 
40 is constructed depends, among other things, on the chemistry (ie. 
acidity) and density of the process flow. 
In addition, supporting means 40 is sized to be inserted into (through open 
inner element second end 32) and held tightly within inner element 30. 
Supporting means 40 is preferably long enough to support the entire length 
of inner element 30 without distorting the shape of diverting means 100. 
In the preferred embodiment, the length of supporting means 40 is 
substantially equal to the aggregate length of and inner element second 
section 35 and inner element third section 34. In this preferred 
embodiment, supporting means 40 is inserted into and fits within inner 
element second section 35 and inner element third section 34. 
In a preferred embodiment as shown in FIG. 10, supporting means 40 
comprises a rigid, hollow, open-ended cylinder 90 containing holes 91 to 
allow the passage of filtrated process flow therethrough. Although the end 
92 of cylinder 90 adjacent inner element first end 31 can be closed, it is 
preferred that both cylinder ends, 92 and 93, be open. The end 93 of 
cylinder 90 adjacent inner element second end 32 must be open. 
The cross-sectional diameter of cylinder 90 is preferably slightly larger 
than the cross-sectional diameter of inner element second section 35. 
Thus, when cylinder 90 is inserted into inner element 30 (and inner 
element second section 35) through open inner element second end 32, the 
flexible and resilient filter media (in the preferred embodiment) of inner 
element 30 stretches allowing cylinder 90 therein and thereby providing a 
tight fit between cylinder 90 and inner element second section 35. The 
tight fit serves to securely grip cylinder 90 within inner element 30. In 
this way, cylinder 90 securely fits within, provides sufficient support 
to, and is tightly held within inner element 30. 
In another preferred embodiment as shown in FIG. 11, supporting means 40 
comprises a plurality of cartridges 300 which are rigid, hollow, and 
open-ended and which contain holes 301 to allow the passage of filtrated 
process flow therethrough. Although the end 302 of each cartridge 300 
adjacent inner element first end 31 can be closed, it is preferred that 
both cartridge ends, 302 and 303, be open. The end 303 of cartridge 300 
adjacent inner element second end 32 must be open. 
The plurality of cartridges 300 are attached together by a cartridge 
attachment means 310. Preferably, cartridge attachment means 310 comprises 
a polypropylene ring 311 welded unto the plurality of cartridges 300. As 
shown in FIG. 12, the cross-section of the plurality of cartridges 300 (as 
attached together by cartridge attachment means 310) is slightly larger 
than the cross-sectional diameter of inner element second section 35. 
Thus, when the cartridges 300 are inserted into inner element 30 (and 
inner element second section 35) through open inner element second end 32, 
the flexible and resilient filter media (in the preferred embodiment) of 
inner element 30 stretches allowing the cartridges 300 therein and thereby 
providing a tight fit between inner element second section 35 and 
cartridges 300. The tight fit serves to securely grip cartridges 300 
within inner element 30. In this way, the plurality of cartridges 300 
securely fit within, provide sufficient support to, and are tightly held 
within inner element 30. 
In addition, the tight fit between the cartridges 300 and inner element 30 
together with the irregular cross-sectional shape defined by their 
attachment creates ridges 315 on inner element 30 (along the longitudinal 
length of the plurality of cartridges 300) once the cartridges 300 are 
positioned within the inner element 30. The ridges 315 serve to provide 
more filter media surface area to inner element 30. 
Also preferably, supporting means 40 comprises four cartridges 300. 
Cartridge attachment means 310 attaches the four cartridges 300 together 
so that the cross-section of the cartridges 300, as shown in FIG. 12, is 
generally diamond in shape. 
As shown in FIG. 13, filter bag 10 also preferably includes a securing 
means 60. Securing means 60 secures the relative position of inner element 
30 to outer element 20 and is preferably constructed of the same filter 
media material as the outer element 20 and/or the inner element 30. In the 
preferred embodiment, securing means 60 comprises a plurality of 
attachment strips 61. Attachment strips 61 attach the closed inner element 
first end 31 to the open outer element first end 21. 
IN OPERATION 
Generally, in operation, a pressurized process flow enters filter vessel 
200 through process flow inlet 206, passes into container 204 through 
container top opening 213, passes through filter bag 10 and basket 220, 
and exits filter vessel 200 through process flow outlet 210. Solid 
particles in the process flow that are too large to pass through the 
filter media are retained within filter bag 10. All other particles 
(including liquid) permeate through filter bag 10. Thus, the process flow 
is filtered as it passes through filter bag 10. 
After passing through process flow inlet 206, the process flow enters 
container 204 through container top opening 213. Because filter bag 10 is 
suspended on basket lip 226 and basket lip 226 is suspended on container 
top surface groove 214, filter bag 10 encircles the entire container top 
opening 213. Thus, all process flow entering filter vessel 200 necessarily 
passes through and is filtered by filter bag 10. 
The flow enters filter bag 10 through open outer element first end 21 and 
collides with closed inner element first end 31 and diverting means 100. 
Diverting means 100, which corresponds to the conically shaped inner 
element third section 36 and includes closed inner element first end 31 in 
the preferred embodiment, diverts the flow around inner element outside 
surface 38 and within outer element inside surface 28. Diverting means 100 
uniformly diverts the process flow around nose 37 of inner element third 
section 36 throughout the filter media and along the entire length of 
inner element outside surface 38 and outer element inside surface 28. 
Thus, diverting means 100 ensures that the growth of the layer of solids 
within the filter bag 10 is uniform throughout the length of the filter 
bag 10. As has been previously disclosed, the utilization of the entire 
length of the filter bag 10 prolongs the usable life of the filter bag 10. 
In addition, because inner element third section 36 is conically shaped, 
the process flow flows easily and without restriction around nose 37 of 
inner element 30. Thus, filter bag 10 utilizes a greater amount of filter 
media surface area (inner element 30) than comparably sized prior art 
filter bags without inhibiting the flow of the process through filter bag 
10. 
After being diverted by diverting means 100, the flow collides with outer 
element inside surface 28 and/or inner element outside surface 38. Due to 
the presence of rigid supporting means 40, inner element 30 does not 
collapse when the pressurized flow collides with inner element outside 
surface 38. 
The collision impact of the pressurized flow on the outer element inside 
surface 28 causes filtrate to pass through the filter media from the 
inside surface 28 to the outside surface 29 of outer element 20. Likewise, 
the collision impact of the pressurized flow on the inner element outside 
surface 38 causes filtrate to pass through the filter media from the 
outside surface 38 to the inside surface 39 of inner element 30. 
Any solid particles in the process flow which are nonfiltratable collect 
within the filter bag 10 on the inside surface 28 of outer element 20 and 
on the outside surface 38 of inner element 30. Thus, the process flow is 
filtered by filter bag 10. 
After passing through the filter media of inner element 30, filtrate passes 
through the permeable supporting means 40. In the preferred embodiment 
including cylinder 90, after passing through the filter media of inner 
element 30, filtrate passes through the holes 91 of cylinder 90 and exits 
cylinder 90 through open cylinder end 93. In the preferred embodiment 
including cartridges 300, filtrate passes through the holes 301 of 
cartridges 300 and exists cartridges 300 through open cartridge ends 303. 
After passing through supporting means 40, filtrate then permeates through 
permeable basket 220 and flows towards container bottom 208. Filtrate 
exits filter vessel 200 through process flow outlet 210. 
An operator may elect to clean the filter bag 10 by reversing the direction 
of the process flow thereby dislodging the nonfiltratable solid matter 
which has accumulated, through use, on inner element outside surface 38 
and on outer element inside surface 28. If the direction of the flow is 
reversed, then the process flow enters filter vessel 200 through process 
flow outlet 210 and exits filter vessel 200 through process flow inlet 
206. The process flow will thus permeate through outer element 20 from its 
outside surface 29 to its inside surface 28 and through inner element 30 
from its inside surface 39 to its outside surface 38. In such a reverse 
flow condition, supporting means 40 provides structure to and prevents the 
collapse of the filter bag 10. Thus, supporting means 40 also allows for 
the backwash of filter bag 10. 
To replace filter bag 10, an operator must first remove filter vessel lid 
202 from filter vessel container 204 by detaching lid attachment means 
212. Once filter vessel lid 202 is detached, the operator may then lift 
old filter bag 10 (with or without also removing basket 220) from filter 
vessel container 204 and replace it with a new filter bag 10. If filter 
bag 10 includes attachment strips 61 (the preferred embodiment of securing 
means 60), then the operator may lift old filter bag 10 and replace new 
filter bag 10 by clutching the attachment strips 61. 
The foregoing disclosure and description of the invention is illustrative 
and explanatory thereof. Various changes in the details of the illustrated 
construction may be made within the scope of the appended claims without 
departing from the spirit of the invention. The present invention should 
only be limited by the following claims and their legal equivalents.