GB2136305A

GB2136305A - Convertible Liquid Filter

Info

Publication number: GB2136305A
Application number: GB08328196A
Authority: GB
Inventors: Howard William Morgan; Ronald L Hartog
Original assignee: Filter Specialists Inc
Current assignee: Pall Filter Specialists Inc
Priority date: 1983-03-09
Filing date: 1983-10-21
Publication date: 1984-09-19
Also published as: IT1213001B; JPS59154111A; FR2542213B1; GB8328196D0; IT8368262A0; CA1229312A; JPH0366925B2; GB2136305B; NL8304166A; DE3343881A1; FR2542213A1

Abstract

A convertible liquid filter comprises a housing 12 with a removable cover and two alternative internal filtration means (34) and 70 either of which may be located in the housing. One means comprises a bag supported in a perforate basket (Fig. 1 not shown), which is suspended from shoulder 26. The other comprises tubular cartridges 74 upstanding from a plate 60, which is bolted to flange 54. In another embodiment, the cartridges are enclosed by a cylindrical casing which is suspended from the upper shoulder in the same way as the bag, and flange 54 is omitted. The outlet 20 is at the bottom of the housing, and the inlet 18 can be in the side as shown or in the cover. <IMAGE>

Description

SPECIFICATION Convertible Liquid Filter This invention relates to a liquid filter having an insert which converts the filter from a bag-type filter to a cartridge-type filter.

Known liquid filters include both bag-type filters and cartridge-type filters. However, there is no known filter which provides for the use of a single filter housing which can accommodate either a filter bag or a filter cartridge without having to reverse liquid flow through the filter.

The aim of the invention is to provide a liquid filter which can be converted for use with either a filter bag or a filter cartridge, and to provide a cartridge-carrying insert which is adapted to be fitted within an existing housing for a filter bag.

The present invention provides a liquid filter comprising a housing having side and base walls defining a chamber, the chamber having a top opening defined by the side wall, an inlet port leading to the chamber, an outlet port leading from the chamber, a removable cover adapted to span the top opening in associated sealing engagement with the housing, and two alternatively-usable filtration means positionable within the chamber in the liquid flow path between the inlet port and the outlet port to filter liquid flowing between the ports, one of the filtration means including a reticulated bag, and the other filtration means including a cartridge of tubular-shaped reticulated material.

Advantageously, said other filtration means includes a wall part which forms a liquidimpervious barrier between the inlet port and the outlet port when said other filtration means is positioned within the chamber, the wall part carrying an upstanding reticulated post for supporting the cartridge within the chamber, a longitudinal flow passage being formed in the post, said passage being aligned with an opening formed in the wall part thereby providing a liquid flow path from the inlet port to the outlet port.

Preferably, the wall part carries a plurality of upstanding reticulated posts, each of which supports a respective cartridge, and each of which is formed with a longitudinal flow passage.

The housing may include an inset shoulder portion located within the chamber, the wall part including a base plate adapted to overlie and be attached to said shoulder portion. Conveniently, said shoulder portion is a ring whose outer periphery is secured to the housing side wall. The ring is carried within the filter housing so as not to interfere with the use of a filter bag positioned within the housing. To convert the filter from a bag-type filter to a cartridge-type filter, the bag is removed and a base plate which carries one or more cartridges is secured to the housing ring.

Alternatively, the wall part forms the base of a liquid-impervious cylindrical member having an open upper end, the or each post extending upwardly from said base within the cylindrical member to support the or each cartridge, and wherein the housing is provided with means for supporting the cylindrical member or the bag within the chamber. To convert the filter from a bag-type filter to a cartridge-type filter, the bag is removed and the cylindl ical member is fitted into the filter housing and supported under the filter inlet.

Advantageously, said supporting means is constituted by a shoulder carried by the housing side wall, the cylindtical member and the bag each having an out-turned flange at its upper end adapted to the supported upon said housing shoulder.

Preferably, the or each cartridge is fitted over the respective post, a respective cap being fitted over the or each post upon the upper end of the respective catridge thereby sealing the upper end of that cartridge. A respective biasing means may be provided between the or each cap and the cover, whereby, when the cover is in sealing engagement with the housing, the or each cap is pressed downwardly upon the respective cartridge. Conveniently, a respective spring constitutes the or each biasing means.

The invention also provides an insert for converting a bag-type filter to a cartridge-type filter, the insert comprising a liquid-impervious basket having a side wall and a base wall, the insert being adapted for insertion into a filter housing in place of a filter bag in the liquid flow path between an inlet and an outlet of the filter, the basket being provided with internal upstanding means for supporting a cartridge filtering means within the basket, the basket base wall having an opening, and the cartridge filtering means being supported above the base wall opening, whereby, in use, liquid entering the basket from the filter inlet flows through the cartridge filtering means and the basket base wall opening to leave the filter housing via the filter outlet.

The invention further provides an insert for use in converting a bag-type filter to a cartridge-type filter, the insert comprising a liquid-impervious base plate adapted for insertion into a filter housing in place of a filter bag in the liquid flow path between an inlet and an outlet of the filter, means carried by the base plate for supporting cartridge filtering means on the base plate, the base plate having an opening, the cartridge filtering means being supported above the base plate opening, whereby, in use, liquid flow entering the filter housing passes through the cartridge filtering means and the base plate opening to leave the filter housing through the filter outlet.

Two forms of filter constructed in accordance with the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a longitudinal sectional view of the first form of filter, the filter being shown accommodating a filter bag; Figure 2 is a cross-section taken on the line 2-2 of Figure 4, and shows the housing of the filter of Figure 1 accommodating several filter cartridges, one of the cartridges and its supporting post having portions broken away for illustrative purposes; Figure 3 is a cross-section taken on the line 3-3 of Figure 1; Figure 4 is a cross-section taken on the line 44 of Figure 2; Figure 5 shows details of a filter cartridge and its supporting post, with portions broken away to illustrate its construction;; Figure 6 is a perspective view of the filter cartridge insert of the filter of Figure 1; Figure 7 is a longitudinal sectional view of the second form of filter, the filter being shown accommodating a filter bag; Figure 8 is a cross-section taken on the line 8-8 of Figure 10, and shows the housing of the filter of Figure 7 accommodating several filter cartridges, one of the cartridges and its supporting post having portions broken away for illustrative purposes; Figure 9 is a perspective view of the filter cartridge insert used in the filter of Figure 8, with portions broken away for purposes of illustration; and Figure 10 is a cross-section taken on the line 10-10 of Figure 8.

Referring to the drawings Figures 1 to 6 show a filter 10 having a housing 12. The housing 12 is constituted by a side wall 14 and a base wall 16 which define a chamber. The housing 12 is provided with an inlet port 18 and an outlet port 20. The inlet port 18 is located adjacent to an upper edge 22 of the side wall 14. The side wall 14 of the housing 12 is of a double-walled construction in the region of the inlet port 18, having an inwardly-offset wall part 24 which is connected to the exterior part of the side wall on both sides and just below the inlet port. A shoulder 26 is formed in the wall part 24, the shoulder forming part of an annular flange 28 formed at the open end of the housing 12. A reticulated basket 30 is suspended within the housing 12 by an out-turned flange 32 which rests on the flange 26, 28 adjacent to the upper end of the housing.A filter bag 34 fits within the basket 30, the filter bag being supported at its upper margin 38 by the flange 26, 28 of the housing 12 and on the basket flange 32. A cover 40 fits upon the housing upper edge 22 which, when secured to the housing 12 by nuts 41 (only one of which is shown), makes peripheral sealing engagement with an O-ring 42 seated in a peripheral groove 44 in the upper edge of the housing side wall 14. The cover 40 includes an upwardly-offset portion 46 which is located above the offset wall part 24 of the housing side wall 14. The cover portion 46 forms, in conjunction with the wall part 24, a passage 48 which leads from the inlet port 18 upwardly over the upper margin 38 of the bag 34 and into the interior of the bag.

In order to adapt the filter 10 for use with a filter cartridge, a cartridge-carrying insert 52 (see Figure 2) is provided. The insert 52 includes a ring 54 whose circumferential edge makes a liquid sealing engagement with the housing side wall 14 adjacent to the base wall 16. The ring 54 is positioned so that the basket 30 does not contact the ring when the filter 10 is used as a bag-type filter. The ring 54 is fixed to the housing side wall 14 by welding. The ring 54 has an annular body defining a central opening 56, and includes at least one, and preferably two, threaded bores 58 in its body. The central opening 56 allows for the passage of fluid to the outlet port 20.

The filter insert 52 includes a base plate 60 having openings 62 which align with the ring bores 58 when the base plate is seated on the ring 54. Bolts 64 extend through the plate openings 62, and are screwed into the ring bores 58 to secure the base plate 60 to the ring 54. The base plate 60 is sealed against the ring 54 by an 0-ring 59. Upwardly-extending reticulated tubular centre posts 66 are supported by the base plate 60. Each post 66 has a central passage 68 aligned with a respective base plate opening 62.

The posts 66 are each adapted to support a replaceable filter cartridge 70 which includes a reticulated cylindrical frame 72 wrapped by fibre 74. Each filter cartridge 70 may be of a variety of standard constructions. Each frame 72 slides over a respective post 66. A cap 76 covers the upper end of each filter cartridge 70. A respective helical spring 80 abuts each cap 76. When the cover 40 is closed, the caps 76 are pressed against the cartridges 70 by the springs 80 to seal the upper ends of the cartridge passages 68, and to press the cartridges against the base plate 60.

The filter 10 may be used as a bag-type filter (as shown in Figure 1), or it may be converted to a cartridge-type filter (as shown in Figures 2 to 4).

As a bag-type filter, liquid flow enters the housing 12 through the inlet port 18. It then passes over the housing offset wall 24 and the upper margin 38 of the bag 34, and into the bag where it is strained on passage through the bag. The liquid then leaves the housing 12 via the outlet 20. The course of the liquid flow is shown by arrows 81 in Figure 1. By lifting the basket 30 and the bag 34 out of the housing 12, and by inserting the filter cartridge insert 52 into the housing and bolting its base plate 60 to the ring 54, the filter 10 can be converted to a cartridge-type filter. In this case, liquid flow enters the housing 12 through the inlet port 18. It then passes over the housing offset wall 24, causing at least partial filling of the housing above the base plate 60 and the housing ring 54. Liquid then passes through each filter cartridge 70, and through the openings 67 in the supporting posts 66, into the centre passages 68 of the posts. It then leaves the housing 12 via the opening 56 in the base plate 60 and the outlet port 20. The course of the liquid flow is shown by arrows 83 in Figure 2.

Figures 7 and 8 show the second form of filter 10' having a housing 12'. The housing 12' is constituted by a side wall 14' and a base wall 16'.

A cover 40' fits over the upper edge portion of the side wall 14'. An inlet port 18' is formed in the cover 40', and an outlet port 20' is formed in the housing base wall 16'. A circular shoulder 84 is formed in the upper edge 22' of the side wall 14'.

A filter bag 82 is suspended within the housing 12', with a shape-retaining upper margin 90 of the bag resting on the shoulder 84. An 0-ring 92 is seated in a groove 94 in the side wall upper edge 22', and provides for a peripheral sealing contact between the cover 40' and the side wall upper edge. When the cover 40' is fastened to the housing 12', by tightening nuts 96, the bag upper margin 90 is compressed against the shoulder 84.

It is to be understood that the manner in which the bag 82 is sealed at its upper margin can vary from the manner shown. Also a basket could be utilised with the bag 82 as shown in Figure 1.

In order to adapt the filter 10' for use as a cartridge-type filter, the bag 82 is removed from the housing 12', and a cartridge-carrying insert 98 (see Figure 9) is introduced into the housing.

The insert 98 includes a liquid-impervious cylindrical basket 100 having a side wall 102 and a base wall 104. The basket side wall 102 terminates at its upper end in a an out-turned flange 106. When the basket 100 is inserted into the housing 12', the basket flange 106, which is held in compressive contact with the cover 40', is supported by the housing shoulder 84, and sealed thereagainst by an 0-ring 105. The basket base wall 104 carries upwardly-extending reticulated tubular centre posts 108. Each centre post 108 has a central passage 110 which is aligned with an opening in the basket base wall 104. Each centre post 108 is adapted to support a replaceable filter cartridge 111 which includes a re#iculated cylindrical frame 112 wrapped with fibre 114.Each cartridge frame 112 slides over a respective centre post 108, and is covered by a cap 11 6 to seal the upper end of its central passage 110. A respective helical spring 120 abuts each cap 116, the springs being in contact with the cover 40' to press the caps down thereby sealing and anchoring the underlying cartridges 111.

When in use as a bag-type filter (see Figure 7), liquid enters the filter 10' through the inlet port 18'. It then passes directly into the bag 82, where it is filtered as it flows through the bag into the housing 12'. The liquid leaves the housing 12' via the outlet port 20'. The course of the liquid flow is shown by arrows 121 in Figure 7. In order to convert the filter 10' from a bag-type filter to a cartridge-type filter, the cover 40' is removed, the bag 82 is lifted from the housing 12', the basket 100 is placed in position within the housing, and the cover is replaced. Liquid then enters the filter 10' through the inlet port 18'. It then passes into the basket 100, where it passes through each filter cartridge 111 and through openings 109 in the centre posts 108 into the centre passages 110 of the posts. From the passages 110, the liquid then flows through the basket base wall 104 and into the housing 12'. It leaves the housing via the outlet port 20'. The course of the liquid flow is shown by the arrows 123 in Figure 8.

It will be understood that the cartridge-carrying insert 52 and the ring 54 may be used in the filter 10', and that the cartridge-carrying insert 98 may be used in the filter 10. Moreover, it is contemplated that the base plate 60, with the centre posts 66 removed, could be permanently attached to the filter housing 12 below the filter bag. When it is desired to convert the filter to a cartridge-type filter, the bag and the basket (if used) is removed, and the centre posts 66 screwed into threaded drain openings in base plate 60.

Claims

1. A liquid filter comprising a housing having side and base walls defining a chamber, the chamber having a top opening defined by the side wall, an inlet port leading to the chamber, an outlet port leading from the chamber, a removable cover adapted to span the top opening in associated sealing engagement with the housing, and two alternatively-usable filtration means positionable within the chamber in the liquid flow path between the inlet port and the outlet port to filter liquid flowing between the ports, one of the filtration means including a reticulated bag, and the other filtration means including a cartridge of tubular-shaped reticulated material.

2. A filter as claimed in claim 1, wherein said other filtration means includes a wall part which forms a liquid-impervious barrier between the inlet port and the outlet port when said other filtration means is positioned within the chamber, the wall part carrying an upstanding reticulated post for supporting the cartridge within the chamber, a longitudinal flow passage being formed in the post, said passage being aligned with an opening formed in the wall part thereby providing a liquid flow path from the inlet port to the outlet port.

3. A filter as claimed in claim 2, wherein the wall part carries a plurality of upstanding reticulated posts, each of which supports a respective cartridge, and each of which is formed with a longitudinal flow passage.

4. A filter as claimed in claim 2 or claim 3, wherein the housing includes an inset shoulder portion located within the chamber, the wall part including a base plate adapted to overlie and be attached to said shoulder portion.

5. A filter as claimed in claim 4, wherein said shoulder portion is a ring whose outer periphery is secured to the housing side wall.

6. A filter as claimed in claim 2, wherein the wall part forms the base of a liquid-impervious cylindrical member having an open upper end, the or each post extending upwardly from said base within the cylindrical member to support the or each cartridge, and wherein the housing is provided with means for supporting the cylindrical member or the bag within the chamber.

7. A filter as claimed in claim 6, wherein said supporting means is constituted by a shoulder carried by the housing side wall, the cylindrical member and the bag each having an out-turned flange at its upper end adapted to be supported upon said housing shoulder.

8. A filter as claimed in any one of claims 2 to 7, wherein the or each cartridge is fitted over the respective post, a respective cap being fitted over the or each post upon the upper end of the respective catridge thereby sealing the upper end of that cartridge.

9. A filter as claimed in claim 8, wherein a respective biasing means is provided between the or each cap and the cover, whereby, when the cover is in sealing engagement with the housing, the or each cap is pressed downwardly upon the respective cartridge.

10. A filter as claimed in claim 9, wherein a respective spring constitutes the or each biasing means.

1 A liquid filter substantially as hereinbefore described with reference to, and as illustrated by, Figures 1 to 6 or Figures 7 to 10 of the accompanying drawings.

12. An insert for converting a bag-type filter to a cartridge-type filter, the insert comprising a liquid-impervious basket having a side wall and a base wall, the insert being adapted for insertion into a filter housing in place of a filter bag in the liquid flow path between an inlet and an outlet of the filter, the basket being provided with internal upstanding means for supporting a cartridge filtering means within the basket, the basket base wall having an opening, and the cartridge filtering means being supported above the base wall opening, whereby, in use, liquid entering the basket from the filter inlet flows through the cartridge filtering means and the basket base wall opening to leave the filter housing via the filter outlet.

13. An insert for use in converting a bag-type filter to a cartridge-type filter, the insert comprising a liquid-impervious base plate adapted for insertion into a filter housing in place of a filter bag in the liquid flow path between an inlet and an outlet of the filter, means carried by the base plate for supporting cartridge filtering means on the base plate, the base plate having an opening, the cartridge filtering means being supported above the base plate opening, whereby, in use, liquid flow entering the filter housing passes through the cartridge filtering means and the base plate opening to leave the filter housing through the filter outlet.

14. A cartridge-carrying insert for a liquid filter, the insert being substantially as hereinbefore described with reference to, and as illustrated by, Figures 2 to 6 or Figures 8 to 10 of the accompanying drawings.