WO2016061765A1

WO2016061765A1 - Filtration assembly including filtration module secured by threaded retaining ring

Info

Publication number: WO2016061765A1
Application number: PCT/CN2014/089175
Authority: WO
Inventors: Bi'e LI; Bin He; Liangzhou FAN
Original assignee: Dow Global Technologies Llc
Priority date: 2014-10-22
Filing date: 2014-10-22
Publication date: 2016-04-28

Abstract

A filtration assembly (10) including: a vessel (12) comprising a partition plate (14) dividing the vessel (12) into a first (16) and second (18) chamber and including at least one cylindrical aperture (20) passing therethrough and comprising an outer threaded section (22) adjacent to the second chamber (18), an inner section (24) adjacent to the first chamber (16), and a stepped abutment (26) between the outer and inner sections (22, 24); a filter module (30) including: a separation media extending along an axis (X) between opposing ends (34, 36), and an end cap (40) including a cylindrical base (42) and a distal annular rim (44), wherein the end cap (40) is seated within the aperture (20) with the cylindrical base (42) concentrically located within the inner section (24) of the aperture (20) and the separation media extending into the first chamber (16) of the vessel (12); and a retaining ring (46) located within the outer section (22) of the aperture (20) and including threads (48) extending radially outward and in threaded engagement with the outer threaded section (22) to prevent axial removal of the retaining ring (46).

Description

FILTRATION ASSEMBLY INCLUDING FILTRATION MODULE SECURED BY THREADED RETAINING RING

FIELD

The present invention is directed toward filtration assemblies including one or more filtration modules secured to a partition plate within a vessel.

INTRODUCTION

A common type of filtration assembly includes a tank or vessel housing one or more filtration modules secured from a common partition plate. The plate divides the vessel into two chambers with a first chamber adapted for receiving pressurized feed liquid and the second adapted for receiving permeate passing from the first chamber through the filter module. The filter modules may include an end cap secured through a hole in the partition plate so that the module is suspended in the first chamber immersed in feed liquid. Representative examples of filtration assemblies are described in: WO2014/009047US7083726， US5525220， US5209852 and US477547 and are incorporated herein by reference. The interconnection between the end cap and the partition plate must be fluid tight in order to isolate pressurized feed from permeate. Various means for connecting and sealing the end cap to the partition plate are described in the literature including the use of specialized end caps， e. g. reducing connectors (WO2014/009047) and pressure plates with screw bolts (US477547) . In many embodiments， the individual filter modules have lengths greater than 1m and diameters greater than 0.1 m. Given their size and weight， and limited access within the tank， installation and periodic replacement of modules is time consuming and labor intensive. A simpler means for securing the end caps to the partition plate is desired.

SUMMARY

The present invention utilizes a rotatable retaining ring for securing the end cap of a filter module to the partition plate of a vessel. In a preferred embodiment， the invention includes a filtration assembly (10) including:

i)a vessel (12) comprising a partition plate (14) dividing the vessel (12) into a first (16) and second (18) chamber，

wherein the partition plate (14) includes at least one cylindrical aperture (20) passing therethrough and comprising an outer section (22) adjacent to the second chamber (18) and having a diameter (d₁) ， an inner section (24) adjacent to the first chamber (16) and having a diameter (d₂) wherein (d₂) is smaller than (d₁) ， and a stepped abutment (26) between the outer and inner sections (22， 24) ， wherein at least a portion of outer section (22) includes threads (28) :

ii)a filter module (30) comprising:

a separation media extending along an axis (X) between opposing ends (34， 36) ， and an end cap (40) located at the end (34) and including a cylindrical base (42) having an outer diameter (D₁) and a distal annular rim (44) having an outer diameter (D₂) wherein the (D₂) is larger than (D₁) ；

wherein: and the end cap (40) is seated within the aperture (20) with the cylindrical base (42) concentrically located within the inner section (24) of the aperture (20) and the separation media extending into the first chamber (16) of the vessel (12) ； and

iii)a retaining ring (46) located within the outer section (22) of the aperture (20) and including threads (48) extending radially outward and in threaded engagement with the threads (28) of the outer section (22) of the aperture (20) to prevent axial removal of the retaining ring (46) ， wherein the retaining ring (46) is rotatable within the outer section (22) .

BRIEF DESCRIPTION OF THE DRAWINGS

The figures are not to scale and include idealized views to facilitate description. Where possible， like numerals have been used throughout the figures and written description to designate the same or similar features.

Figure 1 is a cross-sectional view of an embodiment of the invention.

Figure 2 is an enlarged， partially cut-away perspective view of components of the invention including a partition plate (14) ， filter module， end cap (40) and retaining ring (46) .

Figure 3 is an exploded view of Figure 2.

Figure 4 is a cross-sectional view taken along line 4-4 of Figure 3.

DETAILED DESCRIPTION

The invention includes a filtration assembly (10) generally shown in Figure 1 including a vessel (12) . The shape and construction of the vessel is not particularly limited but cylindrical configurations are well suited for high pressure applications. The vessel (12) preferably includes several ports adapted for allowing fluid to enter and exit along with an optional aerator and a removable lid or opening to provide access to the inside of the vessel. The assembly (10) includes a partition plate (14) that divides the vessel (12) into a first (16) and second (18) chamber. As is known in the art， additional partition plates may also be used which further segment the vessel into additional chambers， see for example WO2014/009047. The partition plate (14) includes at least one hole， i. e. cylindrical aperture (20) passing therethrough which provides a passageway between the first (16) and second (18) chambers. As best shown in Figure 2， the aperture (20) includes a stepped inner periphery including an outer section (22) adjacent to the second chamber (18) having a diameter (d₁) and an inner section (24) adjacent to the first chamber (16) having a diameter (d₂) where (d₂) is smaller than (d₁) ， and a stepped abutment (26) between the outer and inner sections (22， 24) . At least a portion of the outer section (22) includes threads (28) extending radially inward from the periphery (diameter (d₁) ) . The aperture (20) may comprise a passageway drilled through or molded in the plate (14) ， or a hole in combination with an insert (as shown in figure 2) that is fixed through the plate (e. g. welded， glued， stamped， etc. ) .

While the assembly (10) is shown including a plurality of filter modules (30) ， a single filter module may be used. The filter module (30) preferably includes an elongated-shaped (e. g. cylindrical) housing (32) extending along an axis (X) between opposing ends (34， 36) . The housing defines an inner chamber (38) that contains a separation media (not shown) . While the separation media may assume a variety of forms， e. g. granular， powder， etc. and serve a variety of functions， e.g. adsorbents， ion exchange media， chelants， etc. ， membrane based media are preferred. In a particularly preferred embodiment， the separation media is a membrane which may be fabricated from a variety of materials into a variety of configurations， e. g. spiral wound， hollow fiber， capillary， flat disks， and tubular membrane modules or “elements” . Representative semi-permeable membranes include those made from: various ceramics， metals， celluloses， polysulfones， polyether sulfones， polyvinylidene fluoride， polyamides， polyacrylonitrile， polyolefins， etc. The membranes may be suitable in a wide range of applications including but not limited to microfiltration (MF) ， ultrafiltration (UF) ， nanofiltration (NF) and reverse osmosis (RO) . In preferred embodiments， the module includes a plurality of semi-permeable hollow fiber membranes. The average pore size of the hollow fiber membranes is preferably from 0.01 to 5 micron， and more preferably from 0.01 to 0.10 micron. In one embodiment not shown， a plurality of semi-permeable hollow fiber membranes is orientated axially within an inner chamber (38) . The ends of the hollow fibers are sealed from the inner chamber by way of well known “potting” techniques wherein one or both ends of the hollow fibers remain open and in fluid communication one or more outer chambers. In an alternative embodiment not shown， the module does not include a housing. In such an embodiment， the separation media extend between the ends (34， 36) of the module and may be directly exposed to the feed liquid. Such configurations are common in membrane bioreactor systems wherein the ends of axially extending hollow fibers are potted to form a tube set which is housed within an end cap or “header. ”

As shown in Figures 2 and 3， an end cap (40) is located at an end (34) of the module (30) and includes a cylindrical base (42) having an outer diameter (D₁) and a distal annular rim (44) having an outer diameter (D₂) . As best shown in Figure 3， the diameter (D₁) of the base (42) is preferably smaller than the diameter (D₂) of the rim (44) ， i. e. D₂ ＞ D₁.

The housing (32) (ifused) and end cap (40) may be constructed from a wide variety of materials， e. g. plastics， ceramics， metals， etc. ， however， in one set of preferred embodiments the housing and end cap is made from an injection moldable plastic such as polyvinyl chloride (PVC) or acrylonitrile butadiene styrene (ABS) .

The filter module (30) may be installed within the vessel (12) by inserting the second end (36) of the module through the aperture (20) from the second chamber (18) and into the first chamber (16) until the end cap (40) is seated within the aperture (20) with its cylindrical base (42) concentrically located within the inner section (24) of the aperture (20) and with the separation media and housing (if used) of the module (30) extending into the first chamber (16) . As used herein， the term “seated” refers to mechanical or pressure engagement. The weight of the module may provide sufficient force to seat the end cap. Alternatively， a forced fit arrangement may be used in instances where the diameters of the various parts are in close tolerance with each other. In a preferred embodiment， the rim (44) of the end cap (40) engages one or more surfaces of the inner periphery， including one or both horizontal and vertical surfaces within the aperture (20) . For example， in a preferred embodiment， the various diameters of the end cap (40) and aperture (20) relate as follows: d₁ ＞ D₂ ＞d₂ ＞ D₁， thereby providing the aforementioned engagement. O-rings or other sealing means may be provided between the engaged surfaces of the end cap (40) and inner periphery including one or both horizontal and vertical surfaces within the aperture (20) . For example， in the embodiment shown in Figure 2， the base (42) of the end cap (40) includes annual grooves (45， 45’ ) for receiving O-rings. Many alternative arrangements may also be used.

As shown in Figures 2 and 3， the end cap (40) of the filter module (30) may be locked or secured into position by installing a retaining ring (46) within the outer section (22) of the aperture (22) . The retaining ring (46) includes threads (48) extending radially outward and in threaded engagement with the threads (28) of the outer section (22) of the aperture (20) . As indicated by a curved arrow， the retaining ring (46) is rotatable within the outer section (22) to permit axial removal of the retaining ring (46) and filter module (30) . Performing these steps in reverse re-secures the module (30) in place within the outer section (22) such that the annular rim (44) is mechanically locked between the retaining ring (46) and stepped abutment (26) . In a preferred embodiment， the retaining ring (46) has an outer diameter (D₃) and d₁＞ D₃ ＞ d₂. With respect to d₁ and D₃， it is further emphasized the respective dimensions are such to provide for threaded engagement. The type of threads used are not particularly limited but they should correspond with each other to provide a rotatable， reversible， mechanical engagement with each other.

While the retaining ring (46) may be stamped， molded or cast from a variety of materials (e. g. plastics， metals， etc. ) ， the ring is preferably rigid such that its outer diameter (D₃) remains relatively unchanged during removal from the retaining groove (26) .

The retaining ring (46) may optionally include holes (50) adapted to receive a spanner wrench or similar tool to facilitate tightening and untightening of the retaining ring (46) from the aperture (20) .

The retaining ring of the present invention permits filter modules to be easily installed and removed from a filter assembly without rotating the module.

Claims

A filtration assembly (10) comprising

i) a vessel (12) comprising a partition plate (14) dividing the vessel (12) into a first (16) and second (18) chamber，

wherein the partition plate (14) includes at least one cylindrical aperture (20) passing therethrough and comprising an outer section (22) adjacent to the second chamber (18) and having a diameter (d₁) ， an inner section (24) adjacent to the first chamber (16) and having a diameter (d₂) wherein (d₂) is smaller than (d₁) ， and a stepped abutment (26) between the outer and inner sections (22， 24) ， wherein at least a portion of outer section (22) includes threads (28) ：

ii) a filter module (30) comprising：

a separation media extending along an axis (X) between opposing ends (34， 36) ， and an end cap (40) located at the end (34) and including a cylindrical base (42) having an outer diameter (D₁) and a distal annular rim (44) having an outer diameter (D₂) wherein the (D₂) is larger than (D₁) ；

wherein： the end cap (40) is seated within the aperture (20) with the cylindrical base (42) concentrically located within the inner section (24) of the aperture (20) and the separation media extending into the first chamber (16) of the vessel (12) ； and

iii) a retaining ring (46) located within the outer section (22) of the aperture (20) and including threads (48) extending radially outward and in threaded engagement with the threads (28) of the outer section (22) of the aperture (20) to prevent axial removal of the retaining ring (46) ， wherein the retaining ring (46) is rotatable within the outer section (22) to permit axial removal of the retaining ring (46) .
The assembly of claim 1 wherein the filter module (30) further comprises an elongated-shaped housing (32) extending along the axis (X) between opposing ends (34， 36) and defining a chamber (38) containing the separation media， and wherein the housing (32) extends into the first chamber (16) of the vessel (12) .
The assembly of claim 1 wherein d₁＞D₂＞d₂＞D₁.