WO1999030803A1 - Filter assembly - Google Patents
Filter assembly Download PDFInfo
- Publication number
- WO1999030803A1 WO1999030803A1 PCT/GB1998/003677 GB9803677W WO9930803A1 WO 1999030803 A1 WO1999030803 A1 WO 1999030803A1 GB 9803677 W GB9803677 W GB 9803677W WO 9930803 A1 WO9930803 A1 WO 9930803A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- body section
- end cap
- filter assembly
- housing
- filter element
- Prior art date
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
- B01D46/0027—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours with additional separating or treating functions
- B01D46/003—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours with additional separating or treating functions including coalescing means for the separation of liquid
- B01D46/0031—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours with additional separating or treating functions including coalescing means for the separation of liquid with collecting, draining means
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
- B01D46/0002—Casings; Housings; Frame constructions
- B01D46/0004—Details of removable closures, lids, caps or filter heads
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
- B01D46/24—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies
- B01D46/2403—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies characterised by the physical shape or structure of the filtering element
- B01D46/2411—Filter cartridges
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
- B01D46/42—Auxiliary equipment or operation thereof
- B01D46/4272—Special valve constructions adapted to filters or filter elements
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2265/00—Casings, housings or mounting for filters specially adapted for separating dispersed particles from gases or vapours
- B01D2265/02—Non-permanent measures for connecting different parts of the filter
- B01D2265/028—Snap, latch or clip connecting means
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2275/00—Filter media structures for filters specially adapted for separating dispersed particles from gases or vapours
- B01D2275/20—Shape of filtering material
- B01D2275/201—Conical shape
Definitions
- This invention relates to a filter assembly for collecting material that is entrained in a gas stream such as particulate solid material or liquid in an aerosol form, and to a tubular filter element for location in a housing to collect such material.
- Filtration of gas in a compressed gas system is generally required so that the gas is sufficiently clean for a subsequent application or to minimise adverse effects of impurities on components of the system. For example removal of compressor oil can be required to minimise chemical contamination and accumulation on valves which might lead to malfunction of the valves, and removal of particulate solid material can be required to minimise abrasion.
- a known filter assembly for use in compressed gas systems is sold by Domnick Hunter Limited under the trade mark OIL-X. It comprises a housing having inlet and outlet ports for the gas stream that is to be filtered and a tubular filter element which can be located in the housing and is configured for the gas stream to flow through its wall, for example generally outwardly from the inside of the filter element to the outside.
- the filter element When the assembly is used to collect liquid in the gas stream (for example which is carried in the stream as an aerosol), the filter element will cause the liquid to coalesce. Coalesced liquid then drains from the filter element and collects in the housing for discharge.
- the housing will include an outlet for discharge of any collected liquid.
- the housing of such a filter assembly comprises a body section in which the filter element is located and a head end cap with the inlet and outlet ports for the gas stream.
- the end cap includes appropriate conduits within it for the gas stream to flow between the ports and the filter element.
- the body section is closed at its base and therefore provides a reservoir in which coalesced liquid that has been filtered from the gas stream can collect.
- the formation of the body section housing with a closed base means that each body section must be made individually, for example by a moulding or casting process. Different tools for use in such processes are required for each configuration of product.
- the present invention provides a filter assembly in which the housing comprises a body section with a constant cross-section along its length and separable end caps.
- the invention provides a filter assembly for collecting material that is entrained in a gas stream, which comprises a housing for a tubular filter element, the housing having an inlet and an outlet for the gas that is to be filtered, and comprising first and second end caps, and a separable body section located between the end caps in which the filter element is located when the assembly is in use, the cross-section of the body section being substantially constant along its length, the first end cap having at least one opening formed in it through which the gas to be filtered can pass into or out of the housing, and the second end cap providing a reservoir into which material collected from the gas by the filter element can collect for disposal.
- the constant cross-section of the body section is such that its cross-section at any two spaced apart points taken on parallel planes are similar and equal figures, apart from features by which the cross-section is specifically modified for example to provide fixation points for other components of the assembly or to provide seals to other components.
- the constant cross-section is such as might be formed by an extrusion process. It is an advantage of the present invention that the body section of the housing can be formed by extrusion, allowing the body section effectively to be formed continuously
- the filter assembly of the present invention has the advantage that the housing can be constructed with a size suitable for the filter element that is to be used in it and for the location in which the assembly is to be used, by cutting the body section to an appropriate length.
- Common end caps can be used for housings with a range of capacities. This flexibility of design has advantages for the user because products can be built to meet the requirements of his application. The flexibility has advantages for the manufacturer of the housing because a range of products can be made without the need to make different moulds for each product. The inventory of parts that the manufacturer is required to maintain for manufacture of a range of products is also minimised. Maintenance is facilitated since parts of a housing that have failed can be replaced without having to replace all of the housing.
- the second end cap has formations for engaging a valve for controlling the discharge of collected liquid from the housing.
- the reservoir is made from a material that is transparent.
- the provision of a reservoir in a separable end cap has the advantage of enabling ready access to the interior of the housing at its lower end, for example for inspection, cleaning or replacement of the reservoir or any valve located within it.
- the second end cap includes a protective cage positioned around the reservoir.
- the volume of the reservoir in the second end cap is at least about 75 cm 3 , more preferably at least about 100 cm 3 , especially at least about 250 cm 3 , for example at least about 350 cm 3 .
- the volume might be less than about 5000 cm 3 , and less than 2000 cm 3 , or less than 1000 cm 3 for some applications.
- the ratio of the volume of the reservoir in the second end cap to the volume of the body section of the housing (measured empty) is at least about 0.1, more preferably at least about 0.2, especially at least about 0.3.
- the ratio of the volume of the reservoir to that of the housing (measured empty) is at least about 0.05, more preferably at least about 0.1, especially at least about 0.15.
- the invention provides a method of making a housing for a filter for collecting material that is entrained in a gas stream, which comprises forming a body section with at least one longitudinally extending formation in its internal wall by extrusion, cutting the body section to an appropriate length, and fastening the body section at each of its ends to respective end caps.
- the internal formation in the body section might stand proud of the internal surface in the manner of a rib. It might be in the form of a groove. A combination of one or more ribs and one or more grooves might be incorporated.
- an internal longitudinal formation can facilitate drainage of liquid that has coalesced in the housing into the bottom of the housing for discharge. This can be important to prevent reentrainment of the liquid in the gas stream as it is discharged from the assembly. It is a particular advantage when the gas stream passes through the wall of the filter element from the internal cavity for discharge from the annular space between the filter element and the internal wall of the housing.
- the internal formation can be used to incorporate a generally transverse groove into the body section in its internal wall for engaging one of the end caps.
- the longitudinally extending formation comprises a rib
- the generally transverse groove can be formed in the rib.
- the longitudinally extending formation comprises a groove
- the generally transverse groove can be formed in the wall of the body section, communicating with the longitudinal groove.
- the width of the internal formation measured as the proportion of the perimeter of the body section that it occupies, is at least about 3%, more preferably at least about 7%, for example at least about 10%.
- the width is preferably not more than about 20%, more preferably not more than about 15%.
- the width of the formation can be expressed in terms of angle of arc.
- the formation will therefore preferably have a width of at least about 10°.
- Formations may be provided in the external wall of the body section.
- the formations might be in the form of fins which are provided in an array which extends around at least a substantial part of the periphery of the body section to increase significantly the surface area of the housing body. Such fins can facilitate heat exchange with the gas that is being filtered in the assembly, generally to reduce the temperature of the gas.
- the assembly can include an identifier plate, and the formations can be arranged on the external surface of the body section to engage the plate to retain it in place on the body section.
- the body section can have a pair of elongate ribs which engage the plate along a pair of opposite edges.
- the plate might be colour coded or might bear information material (for example by printing, embossing, etching etc) as to the manufacturer, operating conditions, safety information, service and maintenance data and so on.
- information material for example by printing, embossing, etching etc.
- the convenient formation of ribs for engaging the plate allows such information to be securely and easily fixed to the body section without any need for fasteners such as rivets or screws. It also has the advantage of being visually appealing.
- the first end cap has at least two ports which can function as the inlet and outlet respectively for the gas to be filtered. Because of the provision of the inlet and outlet, this housing end cap is referred to as the head end cap. It will generally be at the upper end of the housing when the assembly is in use. It can be preferred for the head end cap to have at least three ports which are to provide between them the inlet and outlet for the gas that is to be filtered. The provision of at least three ports can enable selection of the relative orientation of the inlet and the outlet by selection of the ports in the end cap that are to provide the inlet and the outlet respectively.
- the head end cap will generally have a flow conduit within it for directing the flow of gas between the filter medium and one of the ports in the end cap.
- a flow conduit might be used to direct a gas stream from an inlet port to the internal cavity within a tubular filter element, to pass through the wall of the filter element for subsequent discharge through the end cap outlet port.
- the filter element in this arrangement is operating in an in-to-out mode. When the filter element is operating in an out-to-in mode, the flow conduit will extend between the internal cavity within the filter element and the outlet port on the end cap.
- the assembly includes a flow conduit which can be fitted into the head end cap, with one end sealed to a port in the end cap, for directing the flow of gas between a port in the head end cap and the filter medium.
- the connection between the flow conduit and the head end cap might be temporary when separation of the end cap and the flow conduit is required or it might be substantially permanent.
- the use of a flow conduit which is fitted into the head end cap has the advantage that the flow conduit can be made with a configuration that is not restricted by having to be formed as an integral part of the end cap.
- the flow path between the openings can be configured to present a continuous smooth flow path to the gas stream flowing along it between the first and second conduit openings.
- the smooth flow path can be constructed to reduce restriction of the flow of the gas stream compared for example with a flow conduit which presents a discontinuous flow path which is sharply angled or contains steps or other obstructions.
- the flow conduit can be made with additional features during its manufacture. For example, a port might be formed in it for connection to means for indicating the pressure within the conduit. A tang might be formed on the flow conduit which can be received in a recess in the housing when the flow conduit is properly located within the housing end cap. This can provide an indication that the flow conduit is properly located, for example by visual inspection or as a result of the tang being resiliently deformable and being received in the recess with a snap fit.
- the flow conduit can be located in its appropriate position within the end cap by means of interengaging ribs on the flow conduit and the end cap respectively.
- the flow conduit can be located in its appropriate position within the end cap by means of interengaging ribs on the flow conduit and the end cap respectively.
- the flow conduit can have a flange on it whose opposite edges present a pair of ribs which are received between a corresponding pair of ribs on the end cap to retain the flow conduit in sealing contact with a mating surface within the end cap.
- the ribs can be aligned with the axis along which the flow conduit is introduced into the end cap so that the two sets of ribs engage one another as the flow conduit is introduced.
- the ribs are configured so that the mating sealing surfaces on the flow conduit and the end cap are forced together as the flow conduit is introduced into the end cap, to enhance the seal between the surfaces.
- This can be achieved for example by provision of an appropriate taper or wedge shape on the ribs on the flow conduit or the end cap.
- the flow of the gas stream towards and away from the assembly will be generally horizontal.
- the tubular filter element will generally be arranged vertically so that the housing end cap is arranged at the top of the housing with the body section depending below it.
- the body section and the end caps should be capable of being connected to one another with sufficient security to withstand internal pressures to which the assembly is subjected when in use.
- appropriate connections include threaded and bayonet-type connections.
- the body section will generally require localised modification to enable these connections to be made.
- fastenings might be affixed to the body section.
- Formations might be created in the body section by machining, for example involving the formation of threads, threaded bores, generally transversely extending grooves, upstanding hook-type features to engage a groove or other recess, and so on.
- a connection is to be made by means of a bayonet-type fitting, a groove can be provided in the body section to engage a lug on the end cap.
- the groove can be formed in an internal rib in the body section as discussed above.
- the groove might include a detent to provide a restriction to relative rotation of the end cap and the body section as is characteristic of bayonet-type fittings.
- the internal longitudinal formation is used to form a groove for a connection between the body section and another component of the assembly, it will be preferred generally for there to be at least two such formations, for example two or three formations, spaced apart around the body section.
- Features might be included on the body section to form an effective gas-tight seal (to the extent that is required for a particular application having regard to for example the pressure to which the assembly is exposed in use) between the body section and the end caps.
- a groove or a rib might be provided in one or both of the end faces of the body section to engage the end caps, possibly with an intermediate gasket.
- a body section which incorporates additional features such as those described above for sealing or formation of a connection is not to be regarded as not having a constant cross-section when, apart from those features, the cross-section is constant.
- the assembly includes means for indicating when the end caps and the body section are connected to one another sufficiently securely to withstand the internal pressures.
- This can have the advantage of also indicating that a flow conduit that is separable from the head end cap is appropriately located in the end cap, for example when the flow conduit engages the body section (directly or indirectly) and it is through the action of the body section on the flow conduit that the flow conduit is forced into the end cap.
- the indication can be visual, for example involving the appearance of a marking in a window in the housing or the flow conduit.
- the indication can be sensed in other ways, for example by feeling engagement of a resilient member in a recess.
- one of the flow conduit and the housing can bear a resiliently deformable tang and the other of the flow conduit and the housing can have a recess formed in it in which the tang is received when the flow conduit is properly located within the end cap.
- one, especially both, of the body section and the head end cap of the housing will often be formed from a metallic material such as a steel or an aluminium alloy, in particular to enable the housing to withstand the internal pressures to which it is exposed when in use.
- the end cap will then often be made from a casting process.
- Polymeric materials can be appropriate for many applications, for example when the filter assembly is only to be exposed to moderate pressures in use or has a small size.
- a reservoir in the base end cap can be made from a material that is transparent.
- a flow conduit that is separable from the housing prefferably be made from a polymeric material such as a polyolefin, a polyamide, or a polyester.
- the polymeric material can be reinforced for example by fibres.
- the use of a polymeric material for the flow conduit has the advantage that it can conveniently be formed by a moulding process.
- the filter element comprises a tubular body of filter medium and top and bottom end fittings by which the filter medium is supported within the housing.
- a flow conduit that is separable from the housing head end cap can be provided as part of one of the end fittings of the filter element, especially when the end fitting (including the flow conduit) is formed by a moulding operation.
- a support for the filter element can be provided as part of one of the end fittings of the filter element, especially when the end fitting (including the support) is formed by a moulding operation.
- the filter medium will be selected according to the requirements on the assembly when in use, for example in terms of the nature and quantity of the impurity (for example as to whether it comprises liquid impurity or solid impurity or both) in the gas stream, the degree of filtration required of the medium, the pressure to which the assembly is exposed when in use.
- the filter medium will preferably be capable of causing liquid droplets to coalesce.
- Materials suitable for use in a coalescing filter element are known, including those sold by Domnick Hunter Limited under the trade mark OIL-X. Suitable materials include borosilicate and other glass fibres, activated carbon materials, activated silica materials and so on.
- the housing preferably includes an outlet at its second end for liquid entrained in the ⁇ as stream which coalesces in the filter element.
- the assembly includes a support which extends between the filter element and the internal side wall of the housing to restrict the filter element against movement within the housing in a direction along the axis of the filter element.
- the support extends from the end fitting of the filter element at its end remote from the head end cap in a direction towards the side wall of a housing, generally transversely relative to the longitudinal axis of the filter element.
- the angle between the support and the said axis can be at least about 45 °, preferably at least about 60°, more preferably at least about 75°, and possibly 90° or more for some applications when the support will be approximately perpendicular to the axis.
- a suitable support for the filter element can comprise at least three limbs which are arranged to extend between the filter medium and the side wall of a housing in which the filter element is to be used. As a result, the filter element is supported stably within the housing, both along and transverse to its axis.
- the housing has an internal support surface on which the support rests when the filter element is properly located within the housing.
- the support surface can face axially in the housing, towards the end of the housing from which the filter element is inserted into the housing.
- the support surface can be provided by a shoulder or ledge on which the support can rest when the body section and the second end cap are fastened together. Accurate positioning of the support surface can ensure that the seal between the filter element and the housing head end cap is formed reliably when the body section and the head end cap of the housing are connected to one another.
- the support surface on which the support rests is provided at about the interface between the body section and the second end cap.
- the second end cap provides the support surface, facing towards the first end cap, for engaging a support for a filter element located within the body section to restrain the filter element against movement in the body section in a direction away from the first end cap towards the second end cap.
- the support surface can extend around the entire periphery of the second end cap.
- the support surface is provided at about the interface between the body section and the second end cap. For example, it can be provided by the upper edge of the second end cap (not including any lugs that might be provided for engaging the body section) where it engages the bottom of the body section of the housing. It might instead be provided at a point below the interface between the body section and the end cap.
- the support surface can be configured to provide positive location of the support, for example to prevent or at least to restrict rotation of the support relative to the housing.
- the support surface will be continuous around the perimeter of the housing; for example it might be provided in the form of a ledge or shoulder which extends around the entire perimeter of the housing.
- the opening in the second end cap through which material drains into it from the body section is open across substantially the same as the area of the body section (apart from any peripheral features which are provided for support of a filter element or for connection the body section and the end cap) so that the bore defined by the body section extends substantially uninterruted into the end cap. This facilitates substantially unimpeded flow of collected fluid from the filter element into the end cap.
- Figure 1 is a sectional side elevation through a filter assembly according to the invention.
- Figure 2 is an exploded view from below of the filter element and head end cap of the housing of the assembly.
- Figure 3 is an isometric view of the body section of the assembly.
- the assembly of the invention comprises a housing 2 and a filter element 4.
- the housing consists of a body section 6 and head and base end caps 8, 10.
- the filter element is located wholly within the body section 6 of the housing with the ends of the body section extending beyond the ends of the filter element.
- the first (or head) end cap 8 contains an inlet port 12 and an outlet port 14 for a gas that is to be filtered.
- the base (or second) end cap 10 provides a reservoir and has an outlet 16 for liquid that has collected in the assembly. It can conveniently be made from a transparent material so that the level of liquid within it can be inspected. It can include a protective cage 17 for the reservoir.
- the opening in the second end cap through which material drains into it from the body section is open across substantially the same as the area of the body section, to provide unimpeded flow of collected fluid from the filter element into the end cap.
- the filter element 4 comprises a cylindrical wall section 20 formed from a filter medium and top and bottom end fittings 24, 26.
- the wall section defines a cavity 22 within it.
- the material of the filter medium will be selected according to the nature of the gas to be filtered and the material in it that is to be filtered.
- the filter medium will be selected to cause the liquid to coalesce.
- the coalesced liquid within the filter medium will drain through the filter medium and from the filter element.
- Each of the end fittings has a trough 28 formed in it in which the wall section 20 is received and sealed so as to ensure that flow of fluid through the filter element takes place through the filter medium.
- a gas that is to be filtered enters the housing 2 through the inlet port 12 in the head end cap 8 and is directed to the internal cavity 22 within the filter medium by means of a flow conduit 30. It flows outwardly through the filter medium. Any liquid in the gas stream can be coalesced within the filter medium. Any solid particles within the gas stream can also be collected by the filter element.
- Gas that has passed through the filter medium is discharged from the assembly through the outlet port 14 in the head end cap 8.
- connections to the housing end cap for the flow of fluid can be made by means of an adaptor block 90 which can be fitted to the housing head end cap 8 and which bears appropriate formations to make a secure connection to a conduit for the fluid to be filtered or other component.
- the head end cap 8 contains the flow conduit 30 by which the flow of gas between the inlet port 12 in the head end cap and the internal cavity 22 within filter medium 20 is directed.
- the flow conduit 30 has a first conduit opening 32 which is sealed to the inlet port, and a second conduit opening 34 which communicates with the internal cavity 22 within the filter medium.
- the flow conduit has a port 40 in it for connection to a gauge for measuring the differential pressure across the filter element.
- the flow conduit 30 can be formed with its curved shape and integral port and other features by a moulding process, especially when it is formed from polymeric material.
- the flow conduit can be formed as a one-piece moulding with the top end fitting 24 of the filter element 4.
- the inlet port 12 in the head end cap and the corresponding face of the flow conduit present mating planar internal surfaces 44, 46.
- the opposite edges of the surface 46 on the flow conduit present a pair of ribs 48 which are received between a corresponding pair of ribs 50 presented by the surface 44 on the end cap to retain the sealing surfaces in contact with one another.
- the ribs 48 on the flow conduit and the ribs 50 on the end cap are aligned with the axis along which the flow conduit is introduced into the housing end cap so that the two sets of ribs engage one another as the flow conduit is introduced.
- the ribs are tapered appropriately to ensure that the mating sealing surfaces 44, 46 on the flow conduit and the housing head end cap are forced together as the flow conduit is introduced into the end cap, to enhance the seal between the surfaces.
- a sealing gasket is provided in a groove on the surface 46 of the flow conduit around the first conduit opening 32, which is compressed between that surface and the surface 44 on the end cap.
- the port 40 can be received in a downwardly facing socket in the end cap, forming a seal by compression of a gasket between the internal surface of the socket and the external surface of the port.
- the flow conduit 30 bears a downwardly extending deformable tang 60.
- the tang has an outwardly projecting limb 62 which can be received in a slot 64 in the housing end cap 8 when the flow conduit is properly located in the end cap, as shown in Figure 4.
- Location of the limb 62 in the slot 64 is facilitated by a tapered ramp 66 to the slot, causing the tang to be deformed inwardly before springing back into the slot.
- the limb can retain the flow conduit within the end cap, at least until other components of the assembly have been introduced.
- the tang 60 also includes a downwardly extending projection 68 by which the tang can be deformed inwardly to release the limb 62 from the slot, allowing the flow conduit to be released from the end cap.
- the bottom end fitting 26 includes three transversely extending limbs 70 which extend between the filter medium 20 and the internal wall of the housing.
- the end fitting is preferably formed with its three limbs as a one-piece component, especially by moulding.
- the limbs engage a support surface in the form of an upwardly facing ledge 72 on the base end cap 10 of the housing.
- Figure 3 shows the body section of the housing in more detail. It has a constant cross- section such as results from extrusion. It has a plurality of fins which are provided in spaced apart arrays 90 around the periphery of the body section. The fins increase significantly the surface area of the housing body and can facilitate heat exchange with the gas that is being filtered in the assembly, for example to reduce the temperature of the gas.
- the body section also has two pairs of elongate ribs 92 which can be used to locate an identifier plate 94 which can be inserted between them.
- the plate might be colour coded or might bear information material (for example by printing, embossing, etching etc) as to the manufacturer, operating conditions, safety information, service and maintenance data and so on.
- the body section also has a four longitudinally extending internal ribs 96.
- Each rib has a groove 82 formed in it by machining after the extrusion step.
- connection between the head end cap 8 and the body section 6 of the housing can be made by a bayonet arrangement in which four orthogonally arranged lugs 80 on the end cap which are received in the transverse grooves 82 in the rib 96 in the body section.
- a detent 86 on at least some of the lugs 80 can retain the lugs and grooves together, preventing inadvertent rotation which would release the end cap from the body section.
- a similar arrangement of lugs and grooves can be used to form a connection between the base end cap and the body section.
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Physics & Mathematics (AREA)
- Geometry (AREA)
- Filtering Of Dispersed Particles In Gases (AREA)
Abstract
A filter assembly for collecting material that is entrained in a gas stream, which comprises a housing for a tubular filter element, and having an inlet and an outlet for the gas that is to be filtered. The housing comprises first and second end caps, and a separable body section located between the end caps in which the filter element is located when the assembly is in use. The cross section of the body section is substantially constant along its length. The first end cap has at least one opening formed in it through which the gas to be filtered can pass into or out of the housing, and the second end cap provides a reservoir into which material collected from the gas by the filter element can collect for disposal.
Description
FILTER ASSEMBLY
This invention relates to a filter assembly for collecting material that is entrained in a gas stream such as particulate solid material or liquid in an aerosol form, and to a tubular filter element for location in a housing to collect such material.
Filtration of gas in a compressed gas system is generally required so that the gas is sufficiently clean for a subsequent application or to minimise adverse effects of impurities on components of the system. For example removal of compressor oil can be required to minimise chemical contamination and accumulation on valves which might lead to malfunction of the valves, and removal of particulate solid material can be required to minimise abrasion.
A known filter assembly for use in compressed gas systems is sold by Domnick Hunter Limited under the trade mark OIL-X. It comprises a housing having inlet and outlet ports for the gas stream that is to be filtered and a tubular filter element which can be located in the housing and is configured for the gas stream to flow through its wall, for example generally outwardly from the inside of the filter element to the outside. When the assembly is used to collect liquid in the gas stream (for example which is carried in the stream as an aerosol), the filter element will cause the liquid to coalesce. Coalesced liquid then drains from the filter element and collects in the housing for discharge. For such applications, the housing will include an outlet for discharge of any collected liquid.
The housing of such a filter assembly comprises a body section in which the filter element is located and a head end cap with the inlet and outlet ports for the gas stream. The end cap includes appropriate conduits within it for the gas stream to flow between the ports and the filter element. The body section is closed at its base and therefore provides a reservoir in which coalesced liquid that has been filtered from the gas stream can collect. The formation of the body section housing with a closed base means that each body section must be made individually, for example by a moulding or casting process. Different tools for use in such processes are required for each configuration of product.
The present invention provides a filter assembly in which the housing comprises a body section with a constant cross-section along its length and separable end caps.
Accordingly, in one aspect, the invention provides a filter assembly for collecting material that is entrained in a gas stream, which comprises a housing for a tubular filter element, the housing having an inlet and an outlet for the gas that is to be filtered, and comprising first and second end caps, and a separable body section located between the end caps in which the filter element is located when the assembly is in use, the cross-section of the body section being substantially constant along its length, the first end cap having at least one opening formed in it through which the gas to be filtered can pass into or out of the housing, and the second end cap providing a reservoir into which material collected from the gas by the filter element can collect for disposal.
The constant cross-section of the body section is such that its cross-section at any two spaced apart points taken on parallel planes are similar and equal figures, apart from features by which the cross-section is specifically modified for example to provide fixation points for other components of the assembly or to provide seals to other components. The constant cross-section is such as might be formed by an extrusion process. It is an advantage of the present invention that the body section of the housing can be formed by extrusion, allowing the body section effectively to be formed continuously
The filter assembly of the present invention has the advantage that the housing can be constructed with a size suitable for the filter element that is to be used in it and for the location in which the assembly is to be used, by cutting the body section to an appropriate length. Common end caps can be used for housings with a range of capacities. This flexibility of design has advantages for the user because products can be built to meet the requirements of his application. The flexibility has advantages for the manufacturer of the housing because a range of products can be made without the need to make different moulds for each product. The inventory of parts that the manufacturer is required to maintain for manufacture of a range of products is also minimised. Maintenance is facilitated since parts of a housing that have failed can be replaced without having to replace all of the housing.
Preferably, the second end cap has formations for engaging a valve for controlling the discharge of collected liquid from the housing. Preferably, the reservoir is made from a material that is transparent. The provision of a reservoir in a separable end cap has the advantage of enabling ready access to the interior of the housing at its lower end, for example for inspection, cleaning or replacement of the reservoir or any valve located within it. Preferably, the second end cap includes a protective cage positioned around the reservoir.
Preferably, the volume of the reservoir in the second end cap is at least about 75 cm3, more preferably at least about 100 cm3, especially at least about 250 cm3, for example at least about 350 cm3. The volume might be less than about 5000 cm3, and less than 2000 cm3, or less than 1000 cm3 for some applications. Preferably, the ratio of the volume of the reservoir in the second end cap to the volume of the body section of the housing (measured empty) is at least about 0.1, more preferably at least about 0.2, especially at least about 0.3. Preferably, the ratio of the volume of the reservoir to that of the housing (measured empty) is at least about 0.05, more preferably at least about 0.1, especially at least about 0.15.
In another aspect, the invention provides a method of making a housing for a filter for collecting material that is entrained in a gas stream, which comprises forming a body section with at least one longitudinally extending formation in its internal wall by extrusion, cutting the body section to an appropriate length, and fastening the body section at each of its ends to respective end caps.
It is an advantage of the constant cross-section of the body section that it can be made conveniently by extrusion with formations present in the wall. The internal formation in the body section might stand proud of the internal surface in the manner of a rib. It might be in the form of a groove. A combination of one or more ribs and one or more grooves might be incorporated.
It has been found that an internal longitudinal formation can facilitate drainage of liquid that has coalesced in the housing into the bottom of the housing for discharge. This can be important to prevent reentrainment of the liquid in the gas stream as it is discharged from
the assembly. It is a particular advantage when the gas stream passes through the wall of the filter element from the internal cavity for discharge from the annular space between the filter element and the internal wall of the housing.
The internal formation can be used to incorporate a generally transverse groove into the body section in its internal wall for engaging one of the end caps. For example, when the longitudinally extending formation comprises a rib, the generally transverse groove can be formed in the rib. When the longitudinally extending formation comprises a groove, the generally transverse groove can be formed in the wall of the body section, communicating with the longitudinal groove. A filter assembly in which the body section of its housing has a longitudinally extending internal formation, with a communicating transverse formation, is the subject of a copending application entitled Filter Assembly filed with the present application which claims priority from UK patent applications nos. 9726419.6 and 9815957.7 and bearing agents' reference PI 1285 WO. Subject matter disclosed in that application is incorporated in the specification of the present application by this reference.
Preferably, the width of the internal formation, measured as the proportion of the perimeter of the body section that it occupies, is at least about 3%, more preferably at least about 7%, for example at least about 10%. The width is preferably not more than about 20%, more preferably not more than about 15%. When the body section has a generally circular cross- section, the width of the formation can be expressed in terms of angle of arc. The formation will therefore preferably have a width of at least about 10°.
Formations may be provided in the external wall of the body section. For example, the formations might be in the form of fins which are provided in an array which extends around at least a substantial part of the periphery of the body section to increase significantly the surface area of the housing body. Such fins can facilitate heat exchange with the gas that is being filtered in the assembly, generally to reduce the temperature of the gas. The assembly can include an identifier plate, and the formations can be arranged on the external surface of the body section to engage the plate to retain it in place on the body section. For example, the body section can have a pair of elongate ribs which engage the plate along a pair of opposite edges. The plate might be colour coded or might bear
information material (for example by printing, embossing, etching etc) as to the manufacturer, operating conditions, safety information, service and maintenance data and so on. The convenient formation of ribs for engaging the plate allows such information to be securely and easily fixed to the body section without any need for fasteners such as rivets or screws. It also has the advantage of being visually appealing.
Preferably, the first end cap has at least two ports which can function as the inlet and outlet respectively for the gas to be filtered. Because of the provision of the inlet and outlet, this housing end cap is referred to as the head end cap. It will generally be at the upper end of the housing when the assembly is in use. It can be preferred for the head end cap to have at least three ports which are to provide between them the inlet and outlet for the gas that is to be filtered. The provision of at least three ports can enable selection of the relative orientation of the inlet and the outlet by selection of the ports in the end cap that are to provide the inlet and the outlet respectively.
The head end cap will generally have a flow conduit within it for directing the flow of gas between the filter medium and one of the ports in the end cap. Such a conduit might be used to direct a gas stream from an inlet port to the internal cavity within a tubular filter element, to pass through the wall of the filter element for subsequent discharge through the end cap outlet port. The filter element in this arrangement is operating in an in-to-out mode. When the filter element is operating in an out-to-in mode, the flow conduit will extend between the internal cavity within the filter element and the outlet port on the end cap.
It is preferred that the assembly includes a flow conduit which can be fitted into the head end cap, with one end sealed to a port in the end cap, for directing the flow of gas between a port in the head end cap and the filter medium. The connection between the flow conduit and the head end cap might be temporary when separation of the end cap and the flow conduit is required or it might be substantially permanent. The use of a flow conduit which is fitted into the head end cap has the advantage that the flow conduit can be made with a configuration that is not restricted by having to be formed as an integral part of the end cap. For example, when the axes of the openings at the opposite ends of the conduit are not
aligned, the flow path between the openings can be configured to present a continuous smooth flow path to the gas stream flowing along it between the first and second conduit openings. The smooth flow path can be constructed to reduce restriction of the flow of the gas stream compared for example with a flow conduit which presents a discontinuous flow path which is sharply angled or contains steps or other obstructions.
The flow conduit can be made with additional features during its manufacture. For example, a port might be formed in it for connection to means for indicating the pressure within the conduit. A tang might be formed on the flow conduit which can be received in a recess in the housing when the flow conduit is properly located within the housing end cap. This can provide an indication that the flow conduit is properly located, for example by visual inspection or as a result of the tang being resiliently deformable and being received in the recess with a snap fit. The flow conduit can be located in its appropriate position within the end cap by means of interengaging ribs on the flow conduit and the end cap respectively. Details of a filter assembly with a separable flow conduit which is located against a port in a housing by sliding it generally transversely relative to the direction of flow of gas through the port are disclosed in the copending application entitled Filter Assembly filed with the present application which claims priority from UK patent applications nos. 9726415.4 and 9815961.9 and bearing agents' reference PI 1281 WO. Details of a filter assembly in which a flow conduit is located in an end cap of a housing, which also includes a body section for receiving the filter element, are disclosed in the copending application entitled Filter Assembly filed with the present application which claims priority from UK patent applications nos. 9726415.4 and 9815959.3 and bearing agents' reference PI 1282WO. Subject matter disclosed in these applications is incorporated in the specification of the present application by these references.
When the flow conduit is separable from the end cap, it is preferred that at least one of the ports has formations for engaging the flow conduit, in particular to retain it in sealing engagement with the port. For example, the flow conduit can be located in its appropriate position within the end cap by means of interengaging ribs on the flow conduit and the end cap respectively. For example, the flow conduit can have a flange on it whose opposite edges present a pair of ribs which are received between a corresponding pair of ribs on the
end cap to retain the flow conduit in sealing contact with a mating surface within the end cap. The ribs can be aligned with the axis along which the flow conduit is introduced into the end cap so that the two sets of ribs engage one another as the flow conduit is introduced. Preferably, the ribs are configured so that the mating sealing surfaces on the flow conduit and the end cap are forced together as the flow conduit is introduced into the end cap, to enhance the seal between the surfaces. This can be achieved for example by provision of an appropriate taper or wedge shape on the ribs on the flow conduit or the end cap.
Generally, the flow of the gas stream towards and away from the assembly will be generally horizontal. The tubular filter element will generally be arranged vertically so that the housing end cap is arranged at the top of the housing with the body section depending below it.
The body section and the end caps should be capable of being connected to one another with sufficient security to withstand internal pressures to which the assembly is subjected when in use. Examples of appropriate connections include threaded and bayonet-type connections. The body section will generally require localised modification to enable these connections to be made. For example, fastenings might be affixed to the body section. Formations might be created in the body section by machining, for example involving the formation of threads, threaded bores, generally transversely extending grooves, upstanding hook-type features to engage a groove or other recess, and so on. When a connection is to be made by means of a bayonet-type fitting, a groove can be provided in the body section to engage a lug on the end cap. The groove can be formed in an internal rib in the body section as discussed above. The groove might include a detent to provide a restriction to relative rotation of the end cap and the body section as is characteristic of bayonet-type fittings.
When the internal longitudinal formation is used to form a groove for a connection between the body section and another component of the assembly, it will be preferred generally for there to be at least two such formations, for example two or three formations, spaced apart around the body section.
Features might be included on the body section to form an effective gas-tight seal (to the extent that is required for a particular application having regard to for example the pressure to which the assembly is exposed in use) between the body section and the end caps. For example a groove or a rib might be provided in one or both of the end faces of the body section to engage the end caps, possibly with an intermediate gasket.
It will be understood that a body section which incorporates additional features such as those described above for sealing or formation of a connection is not to be regarded as not having a constant cross-section when, apart from those features, the cross-section is constant.
Preferably, the assembly includes means for indicating when the end caps and the body section are connected to one another sufficiently securely to withstand the internal pressures. This can have the advantage of also indicating that a flow conduit that is separable from the head end cap is appropriately located in the end cap, for example when the flow conduit engages the body section (directly or indirectly) and it is through the action of the body section on the flow conduit that the flow conduit is forced into the end cap. The indication can be visual, for example involving the appearance of a marking in a window in the housing or the flow conduit. The indication can be sensed in other ways, for example by feeling engagement of a resilient member in a recess. For example, one of the flow conduit and the housing can bear a resiliently deformable tang and the other of the flow conduit and the housing can have a recess formed in it in which the tang is received when the flow conduit is properly located within the end cap. Details of the location of a deformable tang in a recess to retain connected components of a filter assembly together or to indicate proper connection of the components are disclosed in a copending application entitled Filter Assembly filed with the present application which claims priority from UK patent applications nos. 9726418.8 and 9815955.1 and bearing agents' reference PI 1284WO. Subject matter disclosed in this application is incorporated in the specification of the present application by this reference.
It will often be preferred for one, especially both, of the body section and the head end cap of the housing to be formed from a metallic material such as a steel or an aluminium alloy,
in particular to enable the housing to withstand the internal pressures to which it is exposed when in use. The end cap will then often be made from a casting process. Polymeric materials can be appropriate for many applications, for example when the filter assembly is only to be exposed to moderate pressures in use or has a small size. A reservoir in the base end cap can be made from a material that is transparent.
It will often be preferred for a flow conduit that is separable from the housing to be made from a polymeric material such as a polyolefin, a polyamide, or a polyester. The polymeric material can be reinforced for example by fibres. The use of a polymeric material for the flow conduit has the advantage that it can conveniently be formed by a moulding process.
The filter element comprises a tubular body of filter medium and top and bottom end fittings by which the filter medium is supported within the housing. A flow conduit that is separable from the housing head end cap can be provided as part of one of the end fittings of the filter element, especially when the end fitting (including the flow conduit) is formed by a moulding operation. A support for the filter element can be provided as part of one of the end fittings of the filter element, especially when the end fitting (including the support) is formed by a moulding operation.
The filter medium will be selected according to the requirements on the assembly when in use, for example in terms of the nature and quantity of the impurity (for example as to whether it comprises liquid impurity or solid impurity or both) in the gas stream, the degree of filtration required of the medium, the pressure to which the assembly is exposed when in use. When the impurity to be collected includes liquid (which will generally be present as an aerosol for example of compressor oil), the filter medium will preferably be capable of causing liquid droplets to coalesce. Materials suitable for use in a coalescing filter element are known, including those sold by Domnick Hunter Limited under the trade mark OIL-X. Suitable materials include borosilicate and other glass fibres, activated carbon materials, activated silica materials and so on.
When the filter assembly is intended for use in applications in which liquid impurities are to be collected, the housing preferably includes an outlet at its second end for liquid entrained in the §as stream which coalesces in the filter element.
Preferably, the assembly includes a support which extends between the filter element and the internal side wall of the housing to restrict the filter element against movement within the housing in a direction along the axis of the filter element. Preferably, the support extends from the end fitting of the filter element at its end remote from the head end cap in a direction towards the side wall of a housing, generally transversely relative to the longitudinal axis of the filter element. For example the angle between the support and the said axis can be at least about 45 °, preferably at least about 60°, more preferably at least about 75°, and possibly 90° or more for some applications when the support will be approximately perpendicular to the axis. When the angle between the support and the axis is less than 90°, it will generally be preferred for the support to be inclined in a direction away from the housing head end cap. This has the advantage of enhancing the ability of the support to withstand force exerted by pressurised gas supplied to the housing end cap. A suitable support for the filter element can comprise at least three limbs which are arranged to extend between the filter medium and the side wall of a housing in which the filter element is to be used. As a result, the filter element is supported stably within the housing, both along and transverse to its axis. Details of a support on the second end fitting of a filter element are disclosed in a copending application entitled Filter Assembly filed with the present application which claims priority from UK patent applications nos. 9726416.2 and 9815954.4 and bearing agents' reference PI 1283WO. Subject matter disclosed in that application is incorporated in the specification of the present application by this reference.
Preferably, the housing has an internal support surface on which the support rests when the filter element is properly located within the housing. The support surface can face axially in the housing, towards the end of the housing from which the filter element is inserted into the housing. The support surface can be provided by a shoulder or ledge on which the support can rest when the body section and the second end cap are fastened together. Accurate positioning of the support surface can ensure that the seal between the filter
element and the housing head end cap is formed reliably when the body section and the head end cap of the housing are connected to one another. Preferably, the support surface on which the support rests is provided at about the interface between the body section and the second end cap.
Preferably, the second end cap provides the support surface, facing towards the first end cap, for engaging a support for a filter element located within the body section to restrain the filter element against movement in the body section in a direction away from the first end cap towards the second end cap. The support surface can extend around the entire periphery of the second end cap. Preferably, the support surface is provided at about the interface between the body section and the second end cap. For example, it can be provided by the upper edge of the second end cap (not including any lugs that might be provided for engaging the body section) where it engages the bottom of the body section of the housing. It might instead be provided at a point below the interface between the body section and the end cap.
The support surface can be configured to provide positive location of the support, for example to prevent or at least to restrict rotation of the support relative to the housing. Often, the support surface will be continuous around the perimeter of the housing; for example it might be provided in the form of a ledge or shoulder which extends around the entire perimeter of the housing.
Preferably, the opening in the second end cap through which material drains into it from the body section is open across substantially the same as the area of the body section (apart from any peripheral features which are provided for support of a filter element or for connection the body section and the end cap) so that the bore defined by the body section extends substantially uninterruted into the end cap. This facilitates substantially unimpeded flow of collected fluid from the filter element into the end cap.
The present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:
Figure 1 is a sectional side elevation through a filter assembly according to the invention.
Figure 2 is an exploded view from below of the filter element and head end cap of the housing of the assembly.
Figure 3 is an isometric view of the body section of the assembly.
Referring to the drawings, the assembly of the invention comprises a housing 2 and a filter element 4. The housing consists of a body section 6 and head and base end caps 8, 10. The filter element is located wholly within the body section 6 of the housing with the ends of the body section extending beyond the ends of the filter element.
The first (or head) end cap 8 contains an inlet port 12 and an outlet port 14 for a gas that is to be filtered. The base (or second) end cap 10 provides a reservoir and has an outlet 16 for liquid that has collected in the assembly. It can conveniently be made from a transparent material so that the level of liquid within it can be inspected. It can include a protective cage 17 for the reservoir. The opening in the second end cap through which material drains into it from the body section is open across substantially the same as the area of the body section, to provide unimpeded flow of collected fluid from the filter element into the end cap.
The filter element 4 comprises a cylindrical wall section 20 formed from a filter medium and top and bottom end fittings 24, 26. The wall section defines a cavity 22 within it. The material of the filter medium will be selected according to the nature of the gas to be filtered and the material in it that is to be filtered. When the gas to be filtered contains aerosol droplets of liquid contaminant, the filter medium will be selected to cause the liquid to coalesce. The coalesced liquid within the filter medium will drain through the filter medium and from the filter element. Each of the end fittings has a trough 28 formed in it in which the wall section 20 is received and sealed so as to ensure that flow of fluid through the filter element takes place through the filter medium.
In use, a gas that is to be filtered enters the housing 2 through the inlet port 12 in the head end cap 8 and is directed to the internal cavity 22 within the filter medium by means of a flow conduit 30. It flows outwardly through the filter medium. Any liquid in the gas stream can be coalesced within the filter medium. Any solid particles within the gas stream can also be collected by the filter element.
Gas that has passed through the filter medium is discharged from the assembly through the outlet port 14 in the head end cap 8.
The description above applies to the filter assembly when operated in an in-to-out mode. As discussed above, the assembly can instead be configured for use in an out-to-in mode. In each case, connections to the housing end cap for the flow of fluid can be made by means of an adaptor block 90 which can be fitted to the housing head end cap 8 and which bears appropriate formations to make a secure connection to a conduit for the fluid to be filtered or other component.
The head end cap 8 contains the flow conduit 30 by which the flow of gas between the inlet port 12 in the head end cap and the internal cavity 22 within filter medium 20 is directed. The flow conduit 30 has a first conduit opening 32 which is sealed to the inlet port, and a second conduit opening 34 which communicates with the internal cavity 22 within the filter medium. The flow conduit has a port 40 in it for connection to a gauge for measuring the differential pressure across the filter element. The flow conduit 30 can be formed with its curved shape and integral port and other features by a moulding process, especially when it is formed from polymeric material. The flow conduit can be formed as a one-piece moulding with the top end fitting 24 of the filter element 4.
The inlet port 12 in the head end cap and the corresponding face of the flow conduit present mating planar internal surfaces 44, 46. The opposite edges of the surface 46 on the flow conduit present a pair of ribs 48 which are received between a corresponding pair of ribs 50 presented by the surface 44 on the end cap to retain the sealing surfaces in contact with one another. The ribs 48 on the flow conduit and the ribs 50 on the end cap are aligned with the axis along which the flow conduit is introduced into the housing end cap
so that the two sets of ribs engage one another as the flow conduit is introduced. The ribs are tapered appropriately to ensure that the mating sealing surfaces 44, 46 on the flow conduit and the housing head end cap are forced together as the flow conduit is introduced into the end cap, to enhance the seal between the surfaces. A sealing gasket is provided in a groove on the surface 46 of the flow conduit around the first conduit opening 32, which is compressed between that surface and the surface 44 on the end cap. The port 40 can be received in a downwardly facing socket in the end cap, forming a seal by compression of a gasket between the internal surface of the socket and the external surface of the port.
The flow conduit 30 bears a downwardly extending deformable tang 60. The tang has an outwardly projecting limb 62 which can be received in a slot 64 in the housing end cap 8 when the flow conduit is properly located in the end cap, as shown in Figure 4. Location of the limb 62 in the slot 64 is facilitated by a tapered ramp 66 to the slot, causing the tang to be deformed inwardly before springing back into the slot. Once located in the slot, the limb can retain the flow conduit within the end cap, at least until other components of the assembly have been introduced. The tang 60 also includes a downwardly extending projection 68 by which the tang can be deformed inwardly to release the limb 62 from the slot, allowing the flow conduit to be released from the end cap.
The bottom end fitting 26 includes three transversely extending limbs 70 which extend between the filter medium 20 and the internal wall of the housing. The end fitting is preferably formed with its three limbs as a one-piece component, especially by moulding. The limbs engage a support surface in the form of an upwardly facing ledge 72 on the base end cap 10 of the housing. When the assembly is assembled with head and base end caps connected to the body section 6 of the housing and the flow conduit 30 within the head end cap, the support provided for the filter element by the limbs 70 acting on the base end cap retains the flow conduit within the head end cap 8, against the downward force resulting from the differential pressure across the filter medium.
Figure 3 shows the body section of the housing in more detail. It has a constant cross- section such as results from extrusion. It has a plurality of fins which are provided in spaced apart arrays 90 around the periphery of the body section. The fins increase
significantly the surface area of the housing body and can facilitate heat exchange with the gas that is being filtered in the assembly, for example to reduce the temperature of the gas.
The body section also has two pairs of elongate ribs 92 which can be used to locate an identifier plate 94 which can be inserted between them. The plate might be colour coded or might bear information material (for example by printing, embossing, etching etc) as to the manufacturer, operating conditions, safety information, service and maintenance data and so on.
The body section also has a four longitudinally extending internal ribs 96. Each rib has a groove 82 formed in it by machining after the extrusion step.
The connections between the head end cap 8 and the body section 6 of the housing can be made by a bayonet arrangement in which four orthogonally arranged lugs 80 on the end cap which are received in the transverse grooves 82 in the rib 96 in the body section. A detent 86 on at least some of the lugs 80 can retain the lugs and grooves together, preventing inadvertent rotation which would release the end cap from the body section. A similar arrangement of lugs and grooves can be used to form a connection between the base end cap and the body section.
Appropriate seals will be provided between the components of the housing to prevent unwanted loss of pressure.
Claims
1. A filter assembly for collecting material that is entrained in a gas stream, which comprises a housing for a tubular filter element, the housing having an inlet and an outlet for the gas that is to be filtered, and comprising first and second end caps, and a separable body section located between the end caps in which the filter element is located when the assembly is in use, the cross-section of the body section being substantially constant along its length, the first end cap having at least one opening formed in it through which the gas to be filtered can pass into or out of the housing, and the second end cap providing a reservoir into which material collected from the gas by the filter element can collect for disposal.
2. A filter assembly as claimed in claim 1, in which the reservoir is formed from a material which is sufficiently transparent to enable the level of collected material within it to be inspected.
3. A filter assembly as claimed in claim 1 or claim 2, in which the second end cap has a valved outlet for discharge of material that has collected within the reservoir.
4. A filter assembly as claimed in any one of claims 1 to 3, in which the second end cap includes a protective cage positioned around the reservoir.
5. A filter assembly as claimed in any one of claims 1 to 4, in which the second end cap provides a support surface which faces towards the first end cap, for engaging a support for a filter element located within the body section to restrain the filter element against movement in the body section in a direction away from the first end cap towards the second end cap.
6. A filter assembly as claimed in claim 5, in which the support surface extends around the entire periphery of the second end cap.
7. A filter assembly as claimed in claim 5 or claim 6, in which the support surface is provided at about the interface between the body section and the second end cap.
8. A filter assembly as claimed in any one of claims 1 to 7, in which the area of the opening in the second end cap through which material drains into it from the body section is substantially the same as the area of the body section.
9. A filter assembly as claimed in any one of claims 1 to 8, in which the body section has at least one longitudinally extending formation in its internal wall.
10. A filter assembly as claimed in claim 9, in which the longitudinally extending formation comprises a rib.
11. A filter assembly as claimed in claim 9, in which the longitudinally extending formation comprises a groove.
12. A filter assembly as claimed in any one of claims 9 to 11 , in which the body section has a generally transverse groove formed in its internal wall for engaging one of the end caps.
13. A filter assembly as claimed in claim 12, in which the longitudinally extending formation comprises a rib and in which the generally transverse groove is formed in the rib.
14. A filter assembly as claimed in claim 12, in which the longitudinally extending formation comprises a groove and in which the generally transverse groove is formed in the wall of the body section, communicating with the longitudinal groove.
15. A filter assembly as claimed in any one of claims 1 to 14, in which the body section has at least one longitudinally extending formation in its external wall.
16. A filter assembly as claimed in claim 15, in which the body section has a plurality of longitudinally extending formations in its external wall in the form of fins, which are provided in an array which extends around at least a substantial part of the periphery of the body section to increase significantly the surface area of the body section.
17. A filter assembly as claimed in claim 15 or claim 16, which includes an identifier plate and in which the formations are arranged on the external surface of the body section to engage the plate to retain it in place on the body section.
18. A filter assembly as claimed in any one of claims 1 to 17, in which the body section engages at least one of the end caps by means of bayonet-type formations on the end cap and the body section.
19. A filter assembly as claimed in any one of claims 1 to 18, which includes a filter element located within the housing.
20. A filter assembly as claimed in any one of claims 1 to 19, in which the body section has a formation in at least one of its end faces to enhance the seal between the body section and the end cap that is in contact with that end face of the body section.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU16754/99A AU1675499A (en) | 1997-12-15 | 1998-12-14 | Filter assembly |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GBGB9726419.6A GB9726419D0 (en) | 1997-12-15 | 1997-12-15 | Filter assembly |
GB9726419.6 | 1997-12-15 | ||
GBGB9815963.5A GB9815963D0 (en) | 1998-07-23 | 1998-07-23 | Filter assembly |
GB9815963.5 | 1998-07-23 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1999030803A1 true WO1999030803A1 (en) | 1999-06-24 |
Family
ID=26312769
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/GB1998/003677 WO1999030803A1 (en) | 1997-12-15 | 1998-12-14 | Filter assembly |
Country Status (2)
Country | Link |
---|---|
AU (1) | AU1675499A (en) |
WO (1) | WO1999030803A1 (en) |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6391197B1 (en) * | 1997-12-15 | 2002-05-21 | Domnick Hunter Limited | Filter assembly |
GB2408223A (en) * | 2003-11-20 | 2005-05-25 | Walker Filtration Ltd | A filter assembly |
WO2006013326A1 (en) | 2004-08-05 | 2006-02-09 | Domnick Hunter Limited | Filter assembly |
CN101060906B (en) * | 2004-08-05 | 2011-06-08 | 帕克汉尼芬有限公司 | Filter assembly |
EP2959953A1 (en) * | 2014-06-04 | 2015-12-30 | Walker Filtration Limited | Manifold head for a fluid conditioning column |
WO2020003058A1 (en) * | 2018-06-26 | 2020-01-02 | Atlas Copco Airpower, Naamloze Vennootschap | Filter device and method for installing such filter device |
WO2020003057A1 (en) * | 2018-06-26 | 2020-01-02 | Atlas Copco Airpower, Naamloze Vennootschap | Filter device and method for switching on and off of such a filter device |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4848989A (en) * | 1986-08-29 | 1989-07-18 | Maeda Shell Service Co., Ltd. | In-line filter assembly for compressed air |
DE3909402A1 (en) * | 1989-03-22 | 1990-09-27 | Schumacher Gmbh & Co Kg | Filter for gaseous media |
GB2295970A (en) * | 1994-12-16 | 1996-06-19 | Process Scient Innovations | Filter assembly and cartridge therefor |
-
1998
- 1998-12-14 AU AU16754/99A patent/AU1675499A/en not_active Abandoned
- 1998-12-14 WO PCT/GB1998/003677 patent/WO1999030803A1/en active Application Filing
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4848989A (en) * | 1986-08-29 | 1989-07-18 | Maeda Shell Service Co., Ltd. | In-line filter assembly for compressed air |
DE3909402A1 (en) * | 1989-03-22 | 1990-09-27 | Schumacher Gmbh & Co Kg | Filter for gaseous media |
GB2295970A (en) * | 1994-12-16 | 1996-06-19 | Process Scient Innovations | Filter assembly and cartridge therefor |
Cited By (17)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6391197B1 (en) * | 1997-12-15 | 2002-05-21 | Domnick Hunter Limited | Filter assembly |
GB2408223A (en) * | 2003-11-20 | 2005-05-25 | Walker Filtration Ltd | A filter assembly |
GB2408223B (en) * | 2003-11-20 | 2006-12-20 | Walker Filtration Ltd | Filter assembly |
WO2006013326A1 (en) | 2004-08-05 | 2006-02-09 | Domnick Hunter Limited | Filter assembly |
US7344582B2 (en) | 2004-08-05 | 2008-03-18 | Parker Hannifin Limited | Filter assembly |
CN101060906B (en) * | 2004-08-05 | 2011-06-08 | 帕克汉尼芬有限公司 | Filter assembly |
EP2959953A1 (en) * | 2014-06-04 | 2015-12-30 | Walker Filtration Limited | Manifold head for a fluid conditioning column |
WO2020003057A1 (en) * | 2018-06-26 | 2020-01-02 | Atlas Copco Airpower, Naamloze Vennootschap | Filter device and method for switching on and off of such a filter device |
WO2020003058A1 (en) * | 2018-06-26 | 2020-01-02 | Atlas Copco Airpower, Naamloze Vennootschap | Filter device and method for installing such filter device |
CN110639300A (en) * | 2018-06-26 | 2020-01-03 | 阿特拉斯·科普柯空气动力股份有限公司 | Filter device and method for mounting such a filter device |
CN110639286A (en) * | 2018-06-26 | 2020-01-03 | 阿特拉斯·科普柯空气动力股份有限公司 | Filter device and method for switching on and/or off a filter device |
BE1026434B1 (en) * | 2018-06-26 | 2020-02-03 | Atlas Copco Airpower Nv | Filter device and method for mounting such filter device |
BE1026438B1 (en) * | 2018-06-26 | 2020-02-04 | Atlas Copco Airpower Nv | Filtering device and method for switching off and / or switching on such a filtering device |
US20210229016A1 (en) * | 2018-06-26 | 2021-07-29 | Atlas Copco Airpower N.V. | Filter device and method for mounting such a filter device |
CN110639286B (en) * | 2018-06-26 | 2021-10-26 | 阿特拉斯·科普柯空气动力股份有限公司 | Filter device and method for switching on and/or off a filter device |
CN110639300B (en) * | 2018-06-26 | 2023-05-30 | 阿特拉斯·科普柯空气动力股份有限公司 | Filter device and method for installing such a filter device |
US11890570B2 (en) | 2018-06-26 | 2024-02-06 | Atlas Copco Airpower N.V. | Filter device and method for switching on and/or switching off such filter device |
Also Published As
Publication number | Publication date |
---|---|
AU1675499A (en) | 1999-07-05 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
EP1042046B1 (en) | Filter assembly | |
EP1042045B1 (en) | Filter assembly | |
EP1042047B1 (en) | Filter assembly | |
EP1042044B1 (en) | Filter assembly | |
EP1042043B1 (en) | Filter assembly | |
US6663685B2 (en) | Filter assembly | |
EP1799324B1 (en) | Filter element | |
US7390342B2 (en) | Filter element | |
EP2484425A1 (en) | Filter assembly and method | |
CA2171133C (en) | Liquid filter | |
EP1523377B1 (en) | A coalescing filter element | |
US10675567B2 (en) | Filter element assembly | |
WO1999030803A1 (en) | Filter assembly | |
US20220410053A1 (en) | Filter Element Assembly | |
WO2004045743A9 (en) | Apparatus and method for filtering an aerosol-bearing gas stream | |
CN114762787B (en) | Filter element, liquid separator, method for providing a filter element and use of a filter element in a liquid separator |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AK | Designated states |
Kind code of ref document: A1 Designated state(s): AU CA JP US |
|
AL | Designated countries for regional patents |
Kind code of ref document: A1 Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE |
|
121 | Ep: the epo has been informed by wipo that ep was designated in this application | ||
DFPE | Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101) | ||
122 | Ep: pct application non-entry in european phase | ||
NENP | Non-entry into the national phase |
Ref country code: CA |