Aerosol separator and method

An arrangement for separating a hydrophobic liquid phase from a gaseous stream includes a coalescer filter, a housing, a gas flow direction arrangement, and a liquid collection arrangement. The coalescer filter includes a non-woven media of fibers. The housing includes an interior having a gas flow inlet and a gas flow outlet. The liquid collection arrangement is positioned within the housing construction and is oriented for receiving liquid collected from the coalescer filter and drained therefrom.

TECHNICAL FIELD

This disclosure relates to systems and methods for separating hydrophobic fluids (such as oils) which are entrained as aerosols, from gas streams (for example, air streams). Preferred arrangements also provide for filtration of other fine contaminants, for example carbon material, from the gas streams. Methods for conducting the separations are also provided.

BACKGROUND

Certain gas streams, such as blow-by gases from the crankcase of diesel engines, carry substantial amounts of entrained oils therein, as aerosol. The majority of the oil droplets within the aerosol are generally within the size of 0.1-5.0 microns.

In addition, such gas streams also carry substantial amounts of fine contaminant, such as carbon contaminants. Such contaminants generally have an average particle size of about 0.5-3.0 microns.

In some systems, it is desirable to vent such gases to the atmosphere. In general, it is preferred that before the gases are vented to the atmosphere, they be cleaned of a substantial portion of the aerosol and/or organic particulate contaminants therein.

In other instances, it is desirable to direct the air or gas stream into equipment. When such is the case, it may be desirable to separate aerosol and/or particulates from the stream during the circulation, in order to provide such benefits as: reduced negative effects on the downstream equipment; improved efficiency; recapture of otherwise lost oils; and/or to address environmental concerns.

A variety of efforts have been directed to the above types of concerns. The variables toward which improvements are desired generally concern the following: (a) size/efficiency concerns; that is, a desire for good efficiency of separation while at the same time avoidance of a requirement for a large separator system; (b) cost/efficiency; that is, a desire for good or high efficiency without the requirement of substantially expensive systems; (c) versatility; that is, development of systems that can be adapted for a wide variety of applications and uses, without significant re-engineering; and, (d) cleanability/regeneratability; that is, development of systems which can be readily cleaned (or regenerated) if such becomes desired, after prolonged use.

SUMMARY OF THE DISCLOSURE

A filter arrangement is provided that includes a first stage coalescer filter and a second stage filter element downstream from the coalescer filter. Preferably, the first stage coalescer filter comprises a non-woven fibrous media. The second stage filter element will preferably include pleated media. Preferred constructions will include a filter arrangement including a tubular extension of pleated media defining an open filter interior; a first end cap at one end of the tubular extension of pleated media; the first end cap having an aperture in communication with the open filter interior; a second end cap at an end of the tubular extension of media opposite of the first end cap; and the fibrous media oriented in flow communication with the open filter interior.

In preferred embodiments, a flow construction arrangement is oriented within the open filter interior oriented to direct fluid from the region of pleated media.

Preferably, a preformed insert comprising a frame construction holds the fibrous media, and is secured to the first end cap.

A gas cleaner is described that includes a housing construction with filter arrangements, constructed according to principles herein, operably installed and removably replaceable within the housing construction.

In preferred applications, filter arrangements as described herein are usable to clean blowby gases from the crankcase of an engine. Systems, methods of use, and servicing are described herein.

DETAILED DESCRIPTION

I. A Typical Application—Engine Crankcase Breather Filter

Pressure-charged diesel engines often generate “blow-by” gases, i.e., a flow of air-fuel mixture leaking past pistons from the combustion chambers. Such “blow-by gases” generally comprise a gas phase, for example air or combustion off gases, carrying therein: (a) hydrophobic fluid (e.g., oil including fuel aerosol) principally comprising 0.1-5.0 micron droplets (principally, by number); and, (b) carbon contaminant from combustion, typically comprising carbon particles, a majority of which are about 0.1-10 microns in size. Such “blow-by gases” are generally directed outwardly from the engine block, through a blow-by vent.

Herein when the term “hydrophobic” fluids is used in reference to the entrained liquid aerosol in gas flow, reference is meant to nonaqueous fluids, especially oils. Generally such materials are immiscible in water. Herein the term “gas” or variants thereof, used in connection with the carrier fluid, refers to air, combustion off gases, and other carrier gases for the aerosol.

The gases may carry substantial amounts of other components. Such components may include, for example, copper, lead, silicone, aluminum, iron, chromium, sodium, molybdenum, tin, and other heavy metals.

Engines operating in such systems as trucks, farm machinery, boats, buses, and other systems generally comprising diesel engines, may have significant gas flows contaminated as described above. For example, flow rates and volumes on the order of 2-50 cubic feet per minute (cfm), typically 5 to 10 cfm, are fairly common.

FIG. 1illustrates a schematic indicating a typical system28in which a coalescer/separator arrangement according to the present invention would be utilized. Referring toFIG. 1, block30represents a turbocharged diesel engine. Air is taken to the engine30through an air filter32. Air filter or cleaner32cleans the air taken in from the atmosphere. A turbo34draws the clean air from the air filter32and pushes it into engine30. While in engine30, the air undergoes compression and combustion by engaging with pistons and fuel. During the combustion process, the engine30gives off blow-by gases. A filter arrangement36is in gas flow communication with engine30and cleans the blow-by gases. From filter arrangement36, the air is directed through channel38and through a pressure valve40. From there, the air is again pulled through by the turbo34and into the engine30. Regulator valve or pressure valve40regulates the amount of pressure in the engine crankcase30. Pressure valve40opens more and more, as the pressure in the engine crankcase increases, in order to try to decrease the pressure to an optimal level. The pressure valve40closes to a smaller amount when it is desirable to increase the pressure within the engine. A check valve42is provided, such that when the pressure exceeds a certain amount in the engine crankcase30, the check valve42opens to the atmosphere, to prevent engine damage.

According to this disclosure, the filter arrangement36for separating a hydrophobic liquid phase from a gaseous stream (sometimes referred to herein as a coalescer/separator arrangement) is provided. In operation, a contaminated gas flow is directed into the coalescer/separator arrangement36. Within the arrangement36, the fine oil phase or aerosol phase (i.e., hydrophobic phase) coalesces. The arrangement36is constructed so that as the hydrophobic phase coalesces into droplets, it will drain as a liquid such that it can readily be collected and removed from the system. With preferred arrangements as described hereinbelow, the coalescer or coalescer/separator, especially with the oil phase in part loaded thereon, operates as a prefilter for carbon contaminant carried in the gas stream. Indeed, in preferred systems, as the oil is drained from the system, it will provide some self-cleaning of the coalescer because the oil will carry therein a portion of the trapped carbon contaminant.

Referring toFIG. 2, an embodiment of a crankcase gas filter or filter arrangement36is depicted at reference numeral50. The preferred filter arrangement50depicted includes a housing52. The preferred depicted housing52has a two-piece construction. More specifically, housing52comprises a body assembly54and a removable cover member56. The body assembly54includes body55and lid57.

Referring toFIGS. 2 and 4, the preferred housing52depicted includes the following 3 ports: gas flow inlet port58; gas flow outlet port60; and liquid flow outlet port or liquid drain62.

In general, the filter arrangement50may be generally referenced herein as a “multi-stage” arrangement because it includes both: (a) a coalescer filter, to remove a liquid phase from a liquid entrained gas stream; and, (b) at least a single but could include multiple, downstream or second stage filters, for further purification of the air stream. InFIG. 4, a cross-sectional view of the filter arrangement50including both the housing52and its internal components is depicted. In general, the filter arrangement50includes a first stage coalescer filter64, and a second stage tubular construction of filter media66.

In use, an air or gas stream to be modified is directed through the inlet port58, and through the first stage coalescer filter64. At least a portion of the liquid phase is coalesced and removed from the gaseous stream by the first stage coalescer filter64. The liquid that is coalesced within the first stage coalescer filter64drains by gravity, and in the particular embodiment shown exits the housing52through the liquid flow outlet port62. The gas phase is directed through the second stage media construction66. The media construction66removes at least a portion of particulates from the gas stream, and the cleaned gas stream is then directed outwardly from the housing52through the gas flow outlet60.

As can be seen inFIG. 5, preferably the first stage coalescer filter64and second stage tubular construction of media66are a single, unitary construction forming a filter arrangement or element70. In the preferred embodiment illustrated, the filter element70is removable and replaceable from the housing52. By “unitary” in this context it is meant that the first stage coalescer filter64and the second stage tubular construction of media66cannot be separated from one another without destroying a portion of the assembled element70. In preferred embodiments, end caps202,254form part of the unitary construction.

In reference again toFIG. 4, for the housing52depicted, there is an inlet tube construction72, a regulator valve housing74, a canister portion76, and a outlet tube construction78. In the embodiment shown, each of the inlet tube construction72, regulator valve housing74, canister portion76, and outlet tube construction78form a portion of the body55. Together with the lid57, the body55and lid57are part of the body assembly54.

In the one shown, the inlet tube construction72is a cylindrical member80that defines the gas flow inlet port58. In preferred assemblies, the inlet tube construction78is in gas flow communication with the crankcase of engine30, in order to treat blow-by gases emitted from the crankcase.

The regulator valve housing74depicted is immediately downstream of the inlet tube construction72. The regulator valve housing74includes an outer surrounding wall82defining an open interior84, where the gas to be treated is allowed to flow and collect before passing into the filter element70. The regulator valve housing74also includes an internal wall86forming a neck88. In the one illustrated, the regulator valve housing74also includes a shelf90for holding and supporting the lid57thereon. The neck88holds and supports a regulator valve assembly92(FIG. 4) between the canister portion76and the lid57.

In reference toFIG. 4, the valve assembly92is constructed and arranged to regulate the gas flow from the crankcase of the engine30and through the filter element70. While a variety of valve constructions are contemplated herein, the particular valve assembly92depicted includes diaphragm construction94and a biasing mechanism, such as spring96. InFIG. 4, note that the diaphragm construction94is generally circular with an outermost rim98that is held by and rests upon shelf90. The diaphragm construction94also includes a groove100having a generally U-shaped cross-section and being generally circular, in plan view. The groove100is inboard of the rim98. The groove100helps to keep the diaphragm construction94properly oriented and centered upon the neck88. Secured to the diaphragm construction94is a centering projection102. The centering projection102is sized to extend into the interior portion104of the neck88. In the one shown, the centering projection102is secured to the diaphragm construction94in a region inboard of the groove100. The centering projection102, together with the groove100, helps to keep the diaphragm construction94properly oriented over the neck88.

Still in reference toFIG. 4, in the particular valve assembly92shown, the spring96rests around the outside wall86of the neck88. The spring96applies a force to the diaphragm construction94to pull the diaphragm construction94in a direction toward the neck88and toward the filter element70. Note that there is a gap106between the diaphragm construction94and the neck88. The gap106allows for gas flow from the interior84of the regulator valve housing74and into the interior portion104of the neck88.

In operation, the valve assembly92generally operates to limit the rate of gas flow from the engine crankcase30to the filter element70. The spring96pulls the diaphragm construction94toward the neck88against the pressure exerted by the gas flow inwardly from the gas flow inlet58. The diaphragm construction94is constructed of a flexible material, such as rubber. As such, a diaphragm construction94is allowed to flex in a direction away from the neck88and toward the lid57in the volume108defined between the lid57and the shelf90of the regulator valve housing74.

In reference now toFIG. 6, the canister portion76of the body55includes an outer surrounding wall110, that is generally tubular in construction to define an open interior112for receipt of the filter element70. In the one depicted, the wall110generally is cylindrical to define a circular cross-section. The canister76includes an end wall114that helps to hold and contain the filter element70inside of the canister76. The end wall114includes a projection116extending from a flat, planar portion118. When the filter element70is operably assembled within the housing52, the projection116will act as a secondary, or supplemental sealing mechanism to create a secondary seal120(FIG. 4) between the end wall114of the body55and the element70. It should be appreciated that the primary sealing function is in a radial sealing system between the filter element70and the housing52, which is described in further detail below. The secondary seal120helps to prevent unintended amounts of oil seepage from passing along the end wall114between the filter element70and the housing52.

Still in reference toFIG. 6, note that the body55includes a first tubular region122having a first greatest outer dimension and a second tubular region124having a second greatest outer dimension. In the particular example illustrated, the greatest outer dimensions of the tubular region122and tubular region124are diameters. The diameter of the tubular region122is greater than the diameter of the tubular region124, to create a stepped region126therebetween. The tubular region124defines an inner, annular sealing surface128. As will be described further below, the sealing surface creates a surface of which it can accept pressure of a seal member to create a radial seal therebetween. The tubular region122is spaced from the filter element70, when the filter element70is operably assembled therein, to create a gas flow volume130therebetween.

As can be seen inFIG. 2, the body assembly54and the cover member56are joined to one another along a seam132by a latch arrangement134. The latch arrangement134includes a plurality of latches136that are used to securely hold the cover member56and body assembly54together along the seam132. The latches136allow the cover member56to be selectively removed from the body assembly54in order to access internal components, such as filter element70during servicing. There can be a number of latches, and in the particular embodiment illustrated, there are three latches136. As can be seen inFIGS. 2,4, and6, the body55includes a latch mount138thereon for each of the latches136. InFIG. 2, it can be seen that the cover member56includes appropriate latch receiving structure, such as a slot140, for receiving a hook portion142of each of the latches136.

The body55has an open end144(FIG. 6) that is opposite of the end wall114, in the illustrated embodiment. The open end144is circumscribed by a rim146that is for communicating with a receiving slot148(FIG. 7) in the cover member56.

Turning now to the cover member56illustrated inFIG. 7, note that the cover member56has a bowl or funnel-shaped end second150. The combination of bowl150and drain62comprises a liquid collection arrangement152. In use, as liquid coalesces within the housing52, it will drain downwardly toward the bowl150and will be funneled to the drain62. Typically, appropriate drain lines will be secured to the drain62to direct the collected liquid as desired, for example, to an oil sump.

In reference toFIG. 7, still further detail of the illustrated cover member56is shown. In the particular embodiment illustrated, in the cover member56includes and outer surrounding wall154and an inner wall156spaced from the outer wall154. The outer wall154and the inner wall156together define the slot148. The slot148functions as a volume158for receipt of the body assembly54, in particular, the rim146. The outer surrounding wall154also includes the latch receiving structure140.

The volume158also provides a seat160for holding and containing a gasket member such as O-ring162(FIG.4). In the construction shown, the O-ring162is between the rim146and the seat160. The latch arrangement154provides axial forces to squeeze the cover member56and body assembly54together. This provides a force of the rim146on the O-ring162to create a seal164(FIG. 4) between the cover member56and body assembly54. This seal164prevents unintended amounts of gas flow to flow between the body assembly54and the cover member56. Rather, the seal164forces the gas flow to exit through the gas flow outlet60.

In reference again toFIG. 7, the inner wall156provides an annular, sealing surface166. The annular sealing surface166provides a structure against which a sealing portion of the filter element70is oriented to create a radial seal therewith. This is described in further detail below.

The cover member56also includes an end wall168that is generally normal to the inner wall156. The end wall168acts as a stop170for orientation of the filter element70. In other words, the stop170prevents the filter element70from moving axially within the housing52. Extending from the end wall168is a projection172. When filter element70is operably installed within housing52, the projection172will be pressed against a sealing portion of the filter element70to create a secondary seal174(FIG. 4) with the filter element70. The secondary seal174will help to prevent unintended amounts of oil seepage from traveling from within the filter element70to the volume130outside of the filter element70. Again, the primary sealing function is accomplished by a radial sealing system, to be described further below.

Extending from the end wall168is a sloped wall176that terminates in the liquid flow outlet62. The sloped wall176forms the funnel shaped section or bowl150.

Note that the liquid flow outlet62includes a threaded section178. Threaded section178can be a brass insert, and is convenient for connecting fittings to lead to an oil sump, for example.

Herein, the term “gas flow direction arrangement” or variants thereof will sometimes be used to refer to the portions of arrangements that direct gas flow. For filter arrangement50,FIG. 4, this would include the gas flow inlet58, the inlet tube construction72, the various walls of the housing52(including the walls82,86,110, and154) and the outlet tube construction78, including the gas flow outlet60. The gas flow direction arrangement generally operates to ensure proper gas flow, through the filter element70in proper order.

Attention is now directed toFIGS. 4 and 5. The filter element70is shown inFIG. 4operably assembled within the housing52. By the term “operably assembled” and variants thereof, it is meant that the filter element70is oriented within the housing52such that the seals are in place and gas flow is permitted to flow properly from the inlet58, through the filter element70, and out through the outlet60.

It can be seen inFIGS. 4 and 5that the filter element70includes both the first stage coalescer filter64and the second stage tubular construction media of66in a single construction. When the filter element70is handled, for example during servicing, both the first stage coalescer filter64and the second stage tubular construction of media66are handled together. In general, the tubular construction of media66includes a media pack190arranged in a closed, tubular form to define an open filter interior192. In preferred constructions, the media pack190will be configured to have a generally cylindrical shape, defining a circular cross section.

In certain preferred arrangements, the media pack190includes pleated media194defining a plurality of pleats through which gas to be treated flows. The pleated media194acts as a polishing filter to remove at least some particulates and debris from the gas stream, before exiting the housing52through the gas flow outlet60.

The pleated media194has a first end196and an opposite, second end198. The length of the individual pleats of the pleated media194extends between the first end196and second end198. In the filter element70shown, at the first end196is a first end cap arrangement200. In the particular embodiment shown inFIG. 5, the end cap arrangement200includes an end cap202and the first stage coalescer filter64. In preferred constructions, the end cap arrangement200is a single, unitary structure.

In preferred embodiments, the end cap202includes a ring204of a molded, polymeric material. The ring204defines a center aperture206that, in the preferred embodiment illustrated, is centered in the ring204. By “centered”, it is meant that the aperture206has a center of symmetry that is the same as the center of symmetry of the ring204. In other words, the center206is preferably not eccentrically disposed within the ring204.

In preferred arrangements, the center aperture206will be circular and have a diameter that is not greater than about 50 percent of the diameter of the ring204. In some arrangements, the diameter of the aperture206will be less than 40 percent of the diameter of the ring204.

The ring204also includes an outer, annular surface208. When filter element70is operably assembled within housing52, the outer annular sealing surface208functions as a sealing portion210. In preferred arrangements, the sealing portion210includes a stepped construction212.

In particular, the stepped construction212helps with the insertion and formation of a radial seal214(FIG. 4) between the end-cap arrangement200and the sealing surface128of the housing52. InFIG. 5, the stepped construction212includes a first region of largest diameter216, adjacent to a second region218of a diameter smaller than the first region216, adjacent to a third region220of a diameter smaller than that of the second region218. This stepped construction212of decreasing diameters, results in a construction that helps with the insertion of the filter element70in the body55.

The sealing portion210of the end cap202is preferably made from a compressible material, such that there is radial compression of the sealing portion210against the sealing surface128, when the element is operably installed in the housing52. Example, usable materials for the sealing portion210, and preferably the entire end cap202, are described below. In general, preferred end caps202will comprise a soft, polyurethane foam having an as-molded density of typically, less than 22 lbs per cubic foot, for example about 14-22 lbs. per cubic foot.

Still in reference toFIG. 5, the end cap arrangement200also includes a frame construction222oriented in the center aperture206of the ring204. The frame construction222holds, contains, and encapsulates a region of fibrous media224. In the construction shown, the fibrous media224is used as the first stage coalescer filter64. In certain preferred arrangements, the fibrous media224comprises at least one layer, and typically, a plurality of layers226of nonwoven, nonpleated, non open tubular, coalescing media. In the embodiment shown inFIG. 5, there are two layers226,228of fibrous media224. Certain usable, example materials for the fibrous media224are described further below.

Still in reference toFIG. 5, in the frame construction220depicted, the frame construction222is a multi-piece, in particular, a two-piece construction including a first frame piece230and a second frame piece232. The first frame piece230includes a support grid234in covering relation to the upstream face236of the fibrous media224. The support grid234is a porous, mesh that permits gas flow to flow therethrough and across the fibrous media224. The support grid234provides structural support to the fibrous media224.

Similarly, the second frame piece232includes a porous support grid238in covering relation to the downstream face240of the fibrous media224. The support grid238also provides structural support for the fibrous media224, while permitting gas flow to penetrate therethrough and into the open filter interior192.

In the arrangement shown, the first frame piece230and the second frame piece232are arranged adjacent to each other to form a retaining pocket242between the support grid234and support grid238that holds or encapsulates the fibrous media224. In certain arrangements, the first frame piece230and the second frame piece232fit together, such as by snap engagement.

As can be seen inFIG. 5, in the embodiment depicted, the frame construction222is molded or embedded within the polymeric end cap202, along the inner annular region244of the ring204.

The particular filter element70depicted further includes an inner support liner246and an outer support liner248. Each of the inner liner246and outer liner248extends between the first end196and second end198of the media pack190. The inner liner246and outer liner248help to support the pleated media194. The liners246and248, in typical arrangements, are constructed of a plastic, porous structure that permits gas flow therethrough. The outer liner248circumscribes the pleated media194and the region of fibrous media224.

In the particular embodiment illustrated inFIG. 5, the inner liner246is an integral, unitary part of the second frame piece232. That is, the inner liner246and the second frame piece232are a single member. The inner liner246also forms a drain surface250for allowing the drippage and flow of coalesced liquid from the first stage coalescer filter64down to the bowl150.

The filter element70also includes an end cap254at the second end198of the media pack190. The end cap254preferably is constructed of a molded, polymeric material, such that the pleated media194is potted or embedded therewithin. Similarly, the inner liner246and the outer liner248, in certain preferred embodiments, extend between and are embedded within the molded, polymeric material of the first end cap202and second end cap254. The second end cap254includes an outer annular surface256that forms a sealing portion258. Preferably, the sealing portion258is compressible, such that it is squeezed against the sealing surface166of the cover member56when the filter element70is operably installed within the housing52. The end cap254has an aperture255that is preferably aligned with the liquid flow outlet62to allow coalesced liquid to drain from the first stage coalescer filter64, through the aperture255, and exit through the outlet62.

Attention is directed to FIG.4. When the filter element70is operably installed within the housing52, the sealing portion258is compressed between and against the sealing surface166and the outer support liner248to form a radial seal260therebetween. As can be also seen inFIG. 4, the sealing portion210of the first end cap202is compressed between and against the sealing surface128and the outer support liner248to form radial seal214therebetween. The radial seals214,260provide for the primary sealing system within the filter arrangement50. The radial seals214,260prevent unintended amounts of gas flow to bypass either one or both of the first stage coalescer filter64and second stage polishing filter66.

Attention is again directed to FIG.5. The sealing portion258of the end cap254also preferably includes a stepped construction262. The stepped construction262is analogous to the stepped construction212of end cap202. In the particular embodiment illustrated, there are three steps of decreasing diameter, including step264, step266, and step268. Again, the stepped construction262helps in insertion of the filter element70in the housing52and the formation of radial seal260.

The end cap254preferably comprises a molded, polymeric material, such as molded polyurethane foam having an as-molded density of typically less than 22 lbs per cubic foot, for example, about 14-22 lbs. per cubic foot. One example material is described further below.

Note that when the end caps202and254are molded in place, the end caps202,254; the first and second plastic extensions246,248; the pleated media194; and the non-pleated, non-woven fibrous media24are secured together in the form of unitary, cylindrical filter element70.

An alternative embodiment of filter element70is illustrated inFIG. 8at reference numeral270. Element270is analogous to the element70ofFIG. 5, in that it includes end cap272, end cap274, a region of fibrous media276, pleated media278, and an outer liner280. End cap272includes a central gas stream inlet aperture272a. The element270further includes an inner support liner282potted within, and extending between the end caps272,274. In this embodiment, there is further included a flow construction284to aid in draining liquid that has been coalesced by the fibrous media276.

In the embodiment illustrated inFIG. 8, the flow construction284includes a tube286. In typical arrangements, the tube286extends from the downstream flow face288of the coalescer media276to the aperture290of the end cap274. The length of the tube286can vary between about 33%-95% of the total length of the pleated media278. In many cases, the tube286with have a length of at least 25% of the pleated media278, and usually less than 100% of the length of the pleated media278. In preferred embodiments, the tube286will have at least a section287that is constructed of a generally gas impermeable material, such that gas flow is required to exit from the downstream flow face288, through the tube interior292, past the end tip294of the tube286, and then up into the volume296before flowing through the pleated media278. The volume296is the region between the inner liner282and the tube286. In the particular embodiment depicted, the entire tube286includes the imperforate section287. In other embodiments, there may be portions of the tube286that are perforated, or gas permeable.

In the embodiment depicted, the tube286is part of a frame construction298that is used to trap, encapsulate, or hold the fibrous media276. Typically, the frame construction298will be molded within the end cap272.

The tube286will aid in the drainage of coalesced liquid (typically oil). In operation, the coalesced liquid will drain by gravity along the inside wall300of the tube286, and then drip into the bowl150, and then exit through the liquid flow outlet62. The tube286will help to prevent coalesced liquid from being drawn into the pleated media278.

In the embodiment depicted, the outer wrap340extends between about 25-75% of the length of the pleated media328, typically from the end cap322(holding the fibrous media326) toward the other end cap324(stopping short of the end cap324). The outer wrap340aids in draining liquid that has been coalesced by the fibrous media326, as explained further. In particular, the outer wrap340helps to prevent gas flow through the region342of pleated media328that is masked by the wrap340. This encourages gas flow to travel further in the direction toward the end cap324, and to the region344of media326that is not masked by the wrap340. This helps in the drainage by gravity of coalesced liquid out of the element320.

A. Example Operation and Changeout

In operation, the filter arrangement50works as follows. Blow-by gases from an engine crankcase are taken in through the gas flow inlet port58. The gases pass into the interior84of the regulator valve housing74. The valve assembly92permits passage of the gas through the gap106between the diaphragm construction94and the neck88. The gap106become larger as the pressure from the engine crankcase increases, causing the diaphragm construction94to move against the spring96and into the volume108against the lid57. The gas then flows into the interior portion104of the neck88. From there, it passes through the first stage coalescer filter64. The first stage coalescer filter64is secured within the construction such that the gas is directed through the first stage coalescer filter64before the gas is directed through the pleated media194.

In particular the gas flow passes through the support grid234and into the layer228of fibrous media224. The gas continues to flow downstream and through the layer226, and then through the support grid238. The fibrous media224separates liquids, with any entrained solids, from the rest of the gas stream. The liquid flows out of the media224and either drips directly into the bowl150, or drains along the drain surface250of the inner liner246. The collected liquid flows along the sloped wall176and ultimately through the liquid flow outlet62. This liquid material often is oil, and may be recycled to the crankcase to be reused.

The gas stream that is not coalesced by the first stage coalescer filter64continues on to the second stage filter66. Specifically, the gas flow travels from the open filter interior192through the pleated media194. The gas flow is prevented from bypassing this media due to the radial seals214,260. The pleated media194removes additional particles and solids from the gas stream. In the orientation shown inFIG. 4, the pleated media194has vertically directed pleats, such that particles and any further liquid collects or agglomerates on the pleats and falls or drain by gravity downwardly toward the bowl150. The filtered gas then exits through the gas flow outlet port60. From there, the gases may be directed, for example, to the turbo34of engine30.

It should be noted that secondary seals120,174prevent unintended amounts of collected liquid, such as oil, from seeping between the filter element70and the housing52.

The filter arrangement50is serviced as follows. The cover member56is removed from the body assembly54by releasing the latches136. This permits the cover member56to be removed from the body assembly54. When the cover member56is removed from the body assembly54, the seal164between the body55and cover member56is released. Further, the radial seal260between the filter element70and the cover member56is released. This also provides access to the filter element70, which includes both the first stage coalescer filter64and the second stage tubular construction of media66. The end of the filter element70adjacent to the end cap254is grasped, and the filter element70is pulled in an axial direction from the interior112of the body55. As the filter element70is pulled from the interior112, the radial seal214is released. This step removes simultaneously both the first stage coalescer filter64and the second stage polishing filter66. This filter element70may then be disposed of, such as by incineration.

A second, new, replacement filter element70is then provided. The replacement element70also includes the first stage coalescer filter64and the second stage polishing filter66in an analogous construction as the initial filter element70. The replacement element70including both the first stage64and second stage66is inserted through the open end144of the body55. The filter element70is oriented such that the sealing portion210of the end cap202is compressed between and against the sealing surface128and the outer liner248to form radial seal214therebetween. In preferred embodiments, the filter element70is also oriented such that the end cap202engages and abuts the end wall114of the body55. Next, the cover member56is placed over the end of the filter element70and oriented such that the sealing portion258of the end cap254is compressed between and against the outer liner248and the sealing surface166of the cover member56. This creates the radial seal260. In preferred arrangements, the filter element70is also oriented such that the end cap254axially engages and abuts the stop170of the cover member56.

With both radial seals214and260in place, the cover member56is then locked to the body assembly54by engaging the latches136. This also helps to create the seal164between the cover member56and body55.

B. Example Constructions and Systems

The filter arrangement36is useful on a 1.5 liter-16 liter engine, 50-1200 hp, turbo charged, or super charged, diesel, or natural gas. In one application, the engine is a 250-400 hp, V-8 engine. The engine has a piston displacement of at least 3 liters, typically 7-14 liters. It typically has 8-16 cfm of blow-by gases generated. Preferred filter arrangements36can handle blow-by gases from 1-20 cfm.

In other systems, the filter arrangement36is useful on engines with the following powers: 8 kw-450 kw (11-600 hp); 450-900 kw (600-1200 hp); and greater than 900 kw (>1200 hp). In general, as the power of the engine increases, the second stage pleated media194will be increased in surface area. For example, for engine powers 8 kw-450 kw (11-600 hp), the length of the pleats will be about 4-5 inches; for engine powers 450-900 kw (600-1200 hp), the length of the pleats will be about 6-8 inches; and for engine powers greater than 900 kw (>1200 hp), there will typically be more than one filter arrangement36utilized. In other words, for engine powers greater than 900 kw (>1200 hp), there will be used two filter arrangements36, each one having a second stage pleated media194with a pleat length of 4-7 inches.

It will be understood that a wide variety of specific configurations and applications are feasible, using techniques described herein. The following dimensions are typical examples:

StructureAt leastNo greater than(in.)(in.)(in.)Typicalouter diameter of element 702124-5inner diameter of element 700.5101.5-2.5length of element 703124-6diameter of media 2240.5102-2.5thickness of each layer 226, 2280.0510.1-0.3diameter of inlet 580.531-1.5diameter of gas flow outlet 600.531-1.5diameter of neck 880.531-1.5height of projection 1160.010.250.05-0.1diameter of open end 1443144.5-5.5diameter of lid 573144.5-5.5diameter of diaphragm 963144.5-5diameter of inner wall 1563134.5-5diameter of outer wall 1543145-5.5diameter of liquid flow outlet 620.0520.1-0.5height of projection 1720.010.250.05-0.1length of housing 524157-8

C. Example Materials

In this section, certain example materials useful for the embodiment ofFIGS. 2-7are described. A variety of materials may be used, other than those described herein.

The housing50can be plastic, such as carbon filled nylon.

The media224of the coalescer64is generally non-pleated, non-cylindrical, polyester fibrous media having an average fiber diameter of less than about 18 microns, typically about 12.5 microns and a percent solidity, free state, of no greater than about 1.05%. The media224has an upstream, and a downstream exposed surface area of at least 1 in.2, no greater than about 7 in.2, and typically about 3-4 in.2The material has an average fiber diameter of 1.5 denier (about 12.5 micron), and a solidity in a free state of at least 0.85%. It has a weight of, typically, greater than about 3.1 ounces per square yard. Typically, it has a weight less than 3.8 ounces per square yard. Typical weights are within the range of 3.1-3.8 ounces per square yard (105-129 grams per square meter). Typically, the media has a thickness at 0.002 psi compression (free thickness) of greater than about 0.32 inches. Typically, the media has a thickness at 0.002 psi compression (free thickness) of less than about 0.42 inches. Typical free thicknesses for the media are in the range of 0.32-0.42 inches (8.1-10.7 millimeters). The media has a typical permeability of no less than about 370 feet per minute (113 meters per minute).

The end caps202,254may be a polymeric material. In particular, the end caps202,254can be urethane, and more particularly, foamed polyurethane. One example foamed polyurethane is described in commonly assigned U.S. Pat. No. 5,669,949 for end cap3, herein incorporated by reference. The material can be the following polyurethane, processed to an end product (soft urethane foam) having an “as molded” density of 14-22 pounds per cubic foot (lbs/ft3) and which exhibits a softness such that a 25% deflection requires about a 10 psi pressure. In some embodiments, the “as molded” density varies from the 14-22 lbs/ft3range. The polyurethane comprises a material made with I35453R resin and I305OU isocyanate. The materials should be mixed in a mix ratio of 100 parts I35453 resin to 36.2 parts I3050U isocyanate (by weight). The specific gravity of the resin is 1.04 (8.7 lbs/gallon) and for the isocyanate it is 1.20 (10 lbs/gallon). The materials are typically mixed with a high dynamic shear mixer. The component temperatures should be 70-95° F. The mold temperatures should be 115-135° F.

The materials I35453R and I3050U are available from BASF Corporation, Wyandotte, Mich. 48192.

The frame construction222, inner liner246, outer liner248, and screens234,238can be constructed of plastic, such as carbon filled nylon.

The pleated media tubular filter194is preferably constructed of an oleo-phobic material. One example is synthetic glass fiber filter medium, coated and corrugated to enhance performance in ambient air-oil mist conditions. The media194has a face velocity of at least 0.1 ft/min., no greater than 5 ft/min., and typically about 0.3-0.6 ft./min. The pleat depth is no less than 0.5 in., no greater than 3 in., and typically about 0.75-2 in. The pleat length is at least 1 in., no greater than 15 in., and typically 3-6 in. The pleated media194has an upstream media surface area of at least 2 ft2and preferably about 3-5 ft2. There are at least 30 pleats, no greater than about 150 pleats, and typically about 60-100 pleats. The synthetic glass fiber filter media may be coated with a low surface energy material, such as an aliphatic fluorocarbon material, available from 3M of St. Paul, Minn. Prior to coating and corrugating, the media has a weight of at least 80 pounds/3000 sq. ft; no greater than about 88 pounds/3000 sq. ft; typically in a range from about 80-88 pounds/3000 square feet (136.8±6.5 grams per square meter). The media has a thickness of 0.027±0.004 inches (0.69±0.10 millimeters); a pore size of about 41-53 microns; a resin content of about 21-27%; a burst strength, wet off the machine of 13-23 psi (124±34 kPa); a burst strength wet after 5 minutes at 300° F. of 37±12 psi (255±83 Idea); a burst strength ratio of about 0.30-0.60; and a permeability of 33±6 feet per minute (10.1±1.8 meters per minute). After corrugating and coating, the media has the following properties: corrugation depth of about 0.023-0.027 inches (0.58-0.69 millimeters); a wet tensile strength of about 6-10 pounds per inch (3.6±0.91 kilograms per inch); and a dry burst strength after corrugating of no less than 30 psi (207 kPa).

The ratio of the upstream surface area of the coalescer media224to the upstream surface area of the pleated media194is less than 25%, typically less than 10%, and in some instances, less than 1%. The ratio of the downstream surface area of the coalescer media224to the upstream surface area of the pleated media194is less than 25%, typically less than 10%, and in some instances, less than 1%.

The housing52may be constructed of a molded plastic, such as glass filled nylon. The diaphragm construction94can be constructed of a deflectable material, such as rubber.

Another alternative embodiment of a coalescer filter and gas cleaner arrangement is depicted inFIGS. 10-12at400. The gas cleaner filter arrangement400includes a housing402. The depicted housing402has a two-piece construction. More specifically, housing402comprises a body assembly404and a removable cover member406. The body assembly404includes body405and lid407.

Housing402includes the following four ports: gas flow inlet port405; gas flow outlet port410; port412; and gas flow bypass outlet port414. In general, and in reference now toFIG. 12, the gas cleaner filter arrangement400includes first stage coalescer filter416and second stage filter media418. In use in the arrangement shown, the port412acts as a liquid flow outlet port or liquid drain412. In the arrangement shown, a liquid entrained gas stream is directed through the gas flow inlet port408and then through the first stage coalescer filter416. At least a portion of the liquid phase is coalesced and removed from the gaseous stream by the first stage coalescer filter416. The liquid that is coalesced within the first stage coalescer filter416drains and exits the housing402through the liquid flow outlet port412. The gas phase is directed from a flow passageway423in the first stage coalescer416through the second stage filter media418. The media construction418removes at least a portion of particulates from the gas stream, and the cleaned gas stream is then directed outwardly from the housing402through the gas flow outlet port410.

As with the embodiment depicted inFIG. 5, the first stage coalescer filter416and the second stage filter media418are a single, unitary construction forming a filter arrangement or element420(FIGS.13-15). In preferred designs, the filter element420is removable and replaceable from the housing402. As with the embodiment ofFIG. 5, “unitary” means that the first stage coalescer filter416and second stage media418cannot be separated without destroying a portion of the element420. In preferred embodiments, the first and second end caps444,445are part of the unitary construction.

In reference again toFIGS. 10 and 12, for the body assembly404depicted, there is an inlet tube construction422, a valve housing424, a canister portion426, and an outlet tube construction428. In the embodiment shown, each of the inlet tube construction422, valve housing424, canister portion426, and outlet tube construction428comprise a portion of the body405. Together with the lid407, the body405and the lid407are part of the body assembly404. The lid407, in the embodiment depicted, is secured to the body405through selectively removable mechanical engagement, such as a bolt arrangement409. The bolt arrangement409provides selective access to a regulator valve assembly496.

The filter element420is constructed and arranged to be removably mountable within the housing402. That is, the filter element420and the housing402are designed such that the housing402can be selectively opened in order to access the filter element420. The filter element420is designed to be selectively mountable and removable from within an interior403of the housing402. When the filter element420is oriented as shown inFIG. 12, with all of the seals (to be described below) in place, the filter element420is considered to be operably installed within the housing402.

As mentioned above, the housing402is designed to be selectively openable in order to access the filter element420. In the particular embodiment illustrated, the cover member406is secured to the body405through a latch arrangement429. The latch arrangement429preferably selectively holds the cover member406tightly and securely to and against the body405, when the latch arrangement429is in a locked state. In the one depicted, the latch arrangement429includes at least two latches433, and in this embodiment, first and second wire latches433.

In reference toFIG. 12, note that the body405and cover member406include a seal arrangement421. In particular, note that the cover406includes a pair of opposing flanges413,415defining a receiving slot417therebetween. The body405includes a flange411that fits in the slot417. Preferred embodiments also include an O-ring seal member419seated within the slot417.

FIG. 15depicts the filter element420as it would appear in an uninstalled state, that is, when it is not mounted within the housing402.FIG. 13shows an end view of the filter element420, whileFIG. 14shows an opposite end view of the filter element420. In general, filter element420includes at least second and first regions431,432of filter media. In the filter element420depicted in the drawings, the second region of filter media431includes a tubular extension434that defines a tubular open filter interior436. The second region of media431also comprises the second stage filter media418, when the filter element420is installed in the filter arrangement system400. In preferred constructions, the tubular extension of media434is configured to have a generally cylindrical shape, defining a circular cross-section. In certain preferred arrangements, the second region of media431includes fluted or pleated media438defining a plurality of pleats through which gas to be treated is forced to flow through. The pleated media438, when installed in the filter arrangement400, preferably acts as a polishing filter to remove at least some particulates and debris from the gas stream, and in certain instances, a portion of the entrained liquid, before the gas stream exits the housing402.

The pleated media438has a first end440and an opposite second end441. The length of the individual pleats, in preferred embodiments, extends between the first end440and the second end441. In the filter element420shown, at the first end440, is a first end cap arrangement442. In the particular one shown, the first end cap arrangement442includes an end cap444and a rigid, pre-formed insert446molded therein. In preferred constructions, the first end cap arrangement442is a single, unitary structure. As will be described further below, the pre-formed insert446includes a frame construction450, which holds the first stage coalescer filter416in operable assembly.

Still in reference toFIG. 15, at the second end441of the pleated media438, is a second end cap arrangement443. The second end cap arrangement443includes at least a second end cap445.

As mentioned above, the filter element420includes at least the second and first regions of media431,432. In preferred arrangements, the second region of media431includes pleated media438. The first region of media432, in preferred embodiments, is oriented in extension across the tubular extension434of the second region of media431to be in gas flow communication with the open filter interior436. By the phrase “oriented in extension across the tubular extension”, it is meant that the first region of media432does not radially overlap the second region of media431to itself form a tubular extension; rather, the first region of media432extends across and covers the end cap aperture445. The first region of media432may be itself embedded within the end cap444or be oriented adjacent to but spaced from the end cap444in a direction toward the end cap445. The first region of media432is not necessarily contained within a single plane, but in preferred embodiments, the first region of media432is a non-tubular, non-cylindrical, generally panel construction448. By “panel construction” it is meant that the first region of media432permits gas flow to maintain a generally straight path therethrough. That is, the gas flow is not required to turn a corner as it flows from an upstream face452to a downstream face454.

In preferred embodiments, and in reference toFIG. 15A, the first region of media432also corresponds to the first stage coalescer filter416. In preferred embodiments, the first region of media432includes fibrous media456. In certain preferred embodiments, the fibrous media456includes at least one layer, and preferably, a plurality of layers458of a fibrous bundle of non-woven, non-pleated, non-open tubular, coalescing depth media459. In the embodiments shown inFIGS. 12 and 15, there are two layers461,462of fibrous depth media459. Preferred materials for the fibrous media456are described above in connection with media224of FIG.5.

Attention is directed toFIG. 13, where the first end cap444is shown in plan view. In preferred embodiments, the end cap444includes a ring466of a molded, polymeric material. The ring466defines a center aperture468that, in the preferred embodiment illustrated, is centered in the ring466. In other words, the aperture468has a center of symmetry that is the same as the center of symmetry of the ring466. In the particular embodiment illustrated, the center aperture468is circular. The aperture468functions as a gas stream inlet aperture. The aperture468is preferably aligned (either overlapping or coaxial with) the flow passageway423of the first stage coalescer filter416.

The end cap444includes an axial portion470and an annular or radial portion472. The aperture468provides for gas flow communication with the open filter interior436. The axial portion470of the end cap444includes at least one continuous projection474. In preferred embodiments, the continuous projection474helps to form a secondary seal476(FIG. 12) with the housing402, when the filter element420is operably installed within the housing interior403. In the particular embodiment illustrated inFIG. 13, the continuous projection474forms a circular ring478.

The radial portion472of the end cap444forms an annular sealing portion480. When the filter element420is operably assembled within the housing402, the annular sealing portion480forms a seal member482. In the preferred embodiment shown inFIG. 13, the seal member482is along the inner annular surface of the ring466, to circumscribe the aperture468.

When the filter element420is operably installed within the housing402, the seal member482forms a radial seal484with the housing402. In particular, in the arrangement shown inFIG. 12, the body405of the housing402includes an internal tube486. The tube486includes a rigid wall488that circumscribes and defines a gas flow aperture490. When constructed as shown inFIG. 12, the wall488has a sealing portion492that is designed to extend through the aperture468of the end cap444and into the open filter interior436. The wall488also has an end portion494that may, in certain instances, interact with valve assembly496. The valve assembly496, its operation, and its interaction with the wall488are discussed in further detail below.

InFIG. 12, it can be seen that the radial seal484is formed against the sealing portion492of the tube486. In preferred embodiments, the radial seal484is formed by compression of the material of the first end cap444between and against the sealing portion492of the tube486and the pre-formed insert446embedded within the end cap444. In this context, by “between and against” it is meant that the material of the first end cap444extends transversely the distance between the sealing portion492of the tube486and the pre-formed insert446, and is compressed in dimension due to the rigidity of portion492and insert446.

In reference now toFIG. 15A, the annular sealing portion480, in the particular preferred embodiment illustrated, includes a stepped construction498. The stepped construction498helps with the insertion and formation of the radial seal484between the end cap arrangement442and the sealing portion492of the housing402. In the preferred embodiment illustrated, the stepped construction498includes a plurality of regions of decreasing diameters, extending from the axial portion470of end cap444to the upstream face452of the fibrous media456. InFIG. 15A, the stepped construction498includes a first region of largest diameter501, adjacent to a second region502of a diameter smaller than the first region501, adjacent to a third region503of a diameter smaller than that of the second region502, adjacent to a fourth region504smaller than that of the third region503. This stepped construction498of decreasing diameters results in sealing portion480that helps with the insertion of the filter element420into the housing402and the formation of the radial seal484.

The sealing portion480of the end cap444is preferably made from a compressible material, such that there is radial compression of the sealing portion480against the sealing portion492of the tube486of the housing402. In general, preferred end caps444comprise a soft, polyurethane foam having an as-molded density of about 14-22 pounds per cubic foot. One usable material is described above in connection with the sealing portion410; another usable material is described further below.

Referring again toFIG. 12, the filter arrangement400preferably includes a flow construction arrangement510oriented to direct fluid, such as coalesced liquid, from the first region of media432toward the liquid flow outlet412. In general, the flow construction arrangement510preferably includes a tube512formed by a section513of impervious, continuous, uninterrupted wall514surrounding and defining an open, fluid passage516. In preferred embodiments, the tube512extends from the downstream face454of the first stage coalescer filter416at least partially in a direction toward the second end cap445. In preferred embodiments, the tube512extends a complete distance between the downstream face454and the second end cap445. In the particular arrangement depicted, the tube512forms an aperture520, preferably a fluid exit aperture523, at the end521of the wall514adjacent to the second end cap445. In this manner, in this particular arrangement, liquid that is coalesced by the first stage coalescer filter416is allowed to collect along the interior517of the tube512and drip by gravity to the liquid flow outlet port412. Alternate drain arrangements are also usable. While in the depicted embodiment, the entire wall514includes the imperforate section513, in other embodiments, only portions of the wall514will be imperforate.

In the embodiment ofFIG. 8, the flow construction arrangement284was depicted in the drawing as being generally straight, and unangled. In the embodiment ofFIGS. 12 and 15, the flow construction arrangement510is depicted as a conical section515having a sloped or tapered wall514. In preferred constructions, the angle of taper on the wall514will be adjusted depending upon the overall length of the element420. That is, in preferred constructions, the size of the aperture468generally remains fixed. As the length of the pleats of the pleated media438becomes greater, the length of the overall element420becomes greater, and the angle or taper of the wall514decreases. In many preferred arrangements, the angle of taper, as measured from a longitudinal axis518(FIG. 15) passing through the symmetrical center of the element420, is at least 1° extending from end519(adjacent to the coalescer filter416) to end521. In some arrangements, the angle of taper can be 2-15°, and typically less than 45°. The taper or angle on the wall514helps to direct the coalesced liquid in the direction of the fluid exit aperture520and ultimately through the liquid flow outlet port412.

After passing through the first stage coalescer filter416, the gas flows through the fluid passageway516, out through exit aperture520, and then into a gas flow plenum522. The gas flow plenum522is formed between the wall514of the tube512and the pleated media438. The taper on the wall514causes the gas flow plenum522to be angled between a volume524adjacent to the second end cap445and a volume526adjacent to the first end cap444that is smaller than volume524.

In reference now toFIG. 14, the depicted second end cap445includes a ring506defining a center aperture507. The aperture507allows for the passage of liquid collected by the first stage coalescer filter416to exit the filter element420, in the particular system depicted in FIG.12. The end cap445supports a sealing arrangement508for forming a seal509(FIG. 12) with the housing402. In the embodiment illustrated inFIG. 12, the particular seal509depicted is an axial seal530formed between the filter element420and an inner sealing surface531of the cover member406. In preferred embodiments, the sealing arrangement508includes a projection534extending or projecting in an axial direction from a generally flat, planar portion536of the second end cap445. In many preferred embodiments, the projection534forms a continuous ring538. Preferred constructions include the end cap445and the projection534being a single, unitary, molded construction540. In preferred embodiments, the end cap construction540is made from a polymeric material, preferably, a compressible polymeric material such as polyurethane. In many preferred embodiments, the second end cap445is made from the same material as the first end cap444. The axial seal530helps to prevent gas from the inlet port408from bypassing the first stage coalescer filter416and the second stage construction of filter media418. The axial seal530also helps to prevent the seepage of liquid such as oil from passing to the downstream side of the second stage filter media418.

As mentioned above, the first end cap arrangement442includes pre-formed insert446. In the embodiment depicted inFIGS. 12 and 15, the pre-formed insert446includes frame construction450for holding and encapsulating the fibrous media456. The frame construction450is now further described. In reference toFIG. 15, the particular frame construction450depicted is a multi-piece construction546. In the embodiment shown inFIG. 15A, the multi-piece construction546includes at least a first frame piece550and a second frame piece552. The first frame piece550includes a support grid554in covering relation to the upstream flow face452of the fibrous media456. Preferably, the support grid554is a porous, mesh screen555(FIG. 13) that permits gas flow, including gas entrained with liquid, to flow therethrough and across the coalescer media456. The screen555also provides structural support to the fibrous media456.

Similarly, the second frame piece552includes a support grid556supporting and in covering relation to the downstream flow face454of the fibrous media456. The support grid556preferably includes a porous, mesh screen557(FIG. 14) and provides structural support for the fibrous media456while permitting gas and coalesced liquid to pass therethrough and into the fluid passageway516of the flow construction arrangement510.

In the arrangement shown, the first frame piece550and the second frame piece552are oriented adjacent to each other to form a retaining pocket560between the screen555and the screen557to form a housing562that holds or encapsulates the fibrous media456. In preferred embodiments, the first frame piece550and the second frame piece552mechanically engage, for example, through interlock structure such as a snap engagement564.

In preferred embodiments, the pre-formed insert446forming the frame construction450is molded or embedded within the polymeric end cap444along an inner annular region566of ring568. Ring568, in the embodiment depicted inFIGS. 12 and 15, is integral with and the same piece as the second frame piece552. The ring568generally comprises a surrounding wall570in projection or extending from screen555to the first axial end440of the pleated media438. As can be seen inFIG. 15A, the wall570forms a rigid, backstop a to the compression of the end cap material in the sealing portion480. That is, in preferred constructions, the radial seal484is formed by compression of the sealing portion480between and against the backstop572and the sealing portion492of the wall488.

As also can be appreciated from reviewingFIGS. 12,15and15A, preferred embodiments include the tube512of the flow construction arrangement510as an integral, unitary part of the second frame piece552. As such, in the embodiment illustrated inFIGS. 12 and 15, the particular second frame piece552shown, extends from the end440, which forms the backstop472, along the length of the pleated media438, to the end521forming the exit aperture520.

Still in reference toFIGS. 12 and 15, preferred frame constructions also include a support ring or frame574. The support frame574helps to center the frame construction450and to hold the frame construction450evenly within the open filter interior436. The support frame574can be a variety of arrangements and constructions that provide for structural rigidity between the tube512and an inner perimeter576of the pleated media438. In the particular one depicted inFIGS. 12,14and15, the support frame574includes a ring construction578. The ring construction578depicted mechanically engages the wall514adjacent to the end521, such as by a snap engagement582. The ring construction578depicted includes at least an inner ring584, which engages the wall514, and an outer ring586, which may touch or be close to the inner perimeter576of the second stage tubular construction of filter media418. The inner ring584and outer ring586define a plurality of gas flow apertures588therebetween, separated by a plurality of spokes or ribs590. The ribs590provide for structural support and integrity of the ring construction578. The gas flow apertures588allow for the passage of gas from the first stage coalescer filter416to the second stage filter media418. That is, after the gas flow has passed through the first stage coalescer filter416and through the fluid passage516, it flows through the fluid exit aperture520, turns a corner (about 180°) around the end521of the wall514and flows through the plural apertures588into the gas flow plenum522. From there, the gas flows through the tubular extension of media434.

In certain embodiments, the filter element420will also include an outer support592, such as a liner594. In preferred arrangements, the support592will extend between the first and second end caps444,445, and help to hold or provide support to the pleated media438. In some embodiments, the liner594includes expanded metal. In many arrangements, the liner594, as well as the other parts of the element420, will be non-metallic (at least 98% non-metallic, and preferably 100% non-metallic material). In alternate embodiments, instead of a liner594, the pleated media438will include a support band or roving.

As mentioned above, preferred filter arrangements400include valve assembly496. In the preferred embodiment illustrated inFIG. 12, the valve assembly496provides both a regulator valve function and a bypass valve function. The regulator valve function is first described. The valve housing424includes an outer surrounding wall601defining an open interior603, where the gas be treated, which flows from the engine crank case through the inlet port408, is allowed to flow and collect before passing into the filter element420. In the illustrated valve assembly496, there is a diaphragm602and a biasing mechanism, such as spring605. In preferred embodiments, the diaphragm602is generally circular that is held by and rests upon a shelf608. The shelf608is supported between the lid407and valve housing424. Note that in the preferred embodiment illustrated, there is a gap610between the diaphragm602and the end portion494of the tube486. The gap610allows for gas flow from the interior603of the valve housing424and into the gas flow aperture490of the tube486. During operation, the spring605and the diaphragm602regulate flow into the tube486.

The valve construction496also includes a bypass valve function. As the media in the filter element420becomes occluded and restriction increases to an unacceptably high level, pressures within the interior603of the valve housing424increase. This applies pressure against the diaphragm602and against the spring604, until the gas is allowed to flow into an interior volume612defined by the lid407. The gas then flows through the gas flow bypass outlet port414(FIG.10).

Example Operation and Service

In operation, the depicted filter arrangement400works as follows. Blow-by gases from an engine crankcase are taken in through the gas flow inlet port408. The gases pass into the interior603of the valve housing424. The valve assembly496permits passage of the gas and into the gas flow aperture490. From there, the gas passes through the first stage coalescer filter416.

The gas flow passes through the upstream face452, through the fibrous media456, and out through the downstream face454. The fibrous media456separates liquids, with any entrained solids, from the rest of the gas stream. The liquid flows out of the media456and, in the depicted embodiment, either drips directly into the liquid flow outlet port412, or drains along the wall514of the flow construction arrangement510. After passing through the liquid flow outlet port412, the liquid, which is often oil, may be directed back into the crankcase for reuse.

The gas stream that is not coalesced by the first stage coalescer filter416flows through the fluid passage516, through the exit aperture520, around the end521of the wall514(making about a 180° turn) and into the gas flow plenum522. From the gas flow plenum522, the gas flows through the second stage filter media418, which removes additional particles and solids from the gas stream. The gas flow is prevented from bypassing the second stage media418due to the radial seal484and axial seals530,476. The cleaned gas then flows downstream from the second stage filter media418out through the gas flow outlet port410. From there, the gases may be directed to the turbo of the engine.

The filter arrangement400is serviced as follows. The cover member406is removed from the body assembly404by disengaging the latches433. When the cover member406is removed from the body assembly404, the axial seal530is released. The filter element420is exposed, projecting out of the body405. The filter element420can then be grasped and pulled from the body405. This releases the radial seal484. Removing the filter element420, of course, removes both the first stage coalescer filter416and the second stage media construction418. The entire filter element420may be disposed. In many embodiments, the filter element420is constructed of at least 99% non-metallic materials, such that the filter element420is incineratable.

A second, new filter element420may than be installed. The new filter element420is installed within the housing402by putting the element420through the opening exposed by the removed cover member406. The aperture468of the end cap444is oriented around the inlet tube486, and slid laterally relative to the body405until the radial seal484is in place. Often, this is also when the projection474axially abuts the body interior405and forms an axial seal476.

The cover406is than oriented over the exposed end of the filter element420. The latches433are engaged, to operably secure the cover member406to the body405. This also axially compresses the cover406against the element420, and the axial seal530is formed.

An alternative embodiment of a preformed insert is shown inFIGS. 16-20, generally at650. The insert650is usable in the filter element420in place of the insert446. The insert650lends itself to convenient manufacturing techniques and may be preferred, in certain applications.

In general, the insert650preferably includes a frame construction652; a flow construction arrangement654; and a support ring or frame656. These parts function analogously to the frame construction450, flow construction arrangement510, and support frame574described in connection with FIG.15.

Preferably, the flow construction arrangement654includes a tube660formed by uninterrupted wall662surrounding and defining an open, fluid passage664. The wall662includes a wall section663that is impervious. In the depicted embodiment, the entire wall662includes impervious wall section663. In other embodiments, the wall662may include sections that are permeable to fluid. The wall662has an interior surface666, which permits coalesced liquid to slide and drip to a liquid outlet port. The wall662defines an exit aperture668, at an end670of the tube660. In many applications, the exit aperture668allows both gas and liquid to exit therethrough. For example, in preferred applications, the exit aperture668allows the collected liquid to exit the tube660and flow into an appropriate liquid outlet port.

As with the embodiment ofFIGS. 12 and 15, the wall662, in preferred arrangements is a conical section667, being sloped or tapered from inlet end663of the wall662to exit end670. That is, in preferred embodiments, when the tube660has a circular cross-section, the diameter at the inlet end663is larger than the diameter at the outlet end670. In many arrangements, the diameter at the inlet end663will be on the order of at least 0.5%, no greater than 25%, and typically 1-10% larger than the diameter at the end670.

Still in reference toFIGS. 16 and 18, the frame construction652preferably is provided for holding and encapsulating coalescing media675. The frame construction652in this embodiment, is different from the frame construction450described above. In this particular embodiment, there is a first frame piece681and a second frame piece682. The first frame piece has a wall or an outer annular rim684defining an inner volume685(FIG.19). Axially spanning across one end of the rim681and integral with the wall684is a support grid686, preferably in the form of a porous, mesh screen688. The screen688provides structural support to the media675and permits gas flow to reach the media675.

The first frame piece681also includes an inner rim690, spaced adjacent to the outer rim684. The inner rim690helps to prevent the flow of polyurethane end cap material from blocking the upstream face692of the media675. (Example preferred molding techniques, and the function of the rim690, are described further below.) As can be seen inFIGS. 16 and 17, the inner rim690is connected to the outer rim684with a plurality of ribs694. The rim690is spaced preferably no greater than 5 millimeters from the outer rim684to form end cap material (e.g. polyurethane) flow passages691therebetween.

The wall or rim684preferably defines a recess696(FIG. 19) for engaging and receiving a mating detent698. The detent698is part of the second frame piece682, in the particular preferred embodiment illustrated. The detent698, recess696provides for convenient, quick assembly and permits the first and second frame pieces681,682to be snapped together. Of course, many other embodiments of mechanical engagement between the first and second frame pieces681,682are contemplated.

The second frame piece682preferably includes an annular wall700surrounding and defining an open volume702. In the particular embodiment illustrated, the wall700has a generally circular cross-section, which may be constant (to form a cylinder) or somewhat tapered to conform to the optional taper of the wall662. The second frame piece wall700includes first and second opposite ends,704,706. In the embodiment illustrated, the end704generally corresponds to an inlet end672.

Second frame piece662also preferably includes a support grid708spanning the open volume702and integral with the wall700. Preferably, the grid708comprises a screen710. The screen710provides structural support to the coalescing media675and preferably engages and holds the downstream face712of the media675.

The first and second frame pieces681,682form an interior volume or retaining pocket714to hold, entrap, and encapsulate the coalescing media675. Preferably, the media675is mechanically compressed within the pocket714, such that the grid686engages the upstream face692and the grid708engages the downstream face712. As described above, the wall700includes a plurality of projections or detents678extending or projecting internally into the volume702to engage or snap into the recess696.

The second frame piece682also includes mechanical engagement structure to securably attach to the wall662of the tube660. In particular, the second frame piece and the tube660also includes mechanical engagement structure, such as a detent/recess engagement718. In the particular way shown inFIG. 19, the wall700includes a second plurality of projections720extending or projecting into the interior volume702, while the wall662has a recess722sized to receive the detents or projections720. In this manner, the second frame piece682easily snaps and interlocks with the tube660.

Still in reference toFIGS. 16 and 18, preferred frame constructions652also include support ring or frame656. The support frame656is analogous to the support frame574, described above. As such, the support frame656helps to center the frame construction652and hold it evenly within an open filter interior. The support frame656, in the one depicted, includes a ring construction725having at least an inner ring (728) and an outer ring730. The inner ring728and the outer ring730are preferably joined by a plurality of spokes or ribs732. Between the inner rings728and outer ring730, the ring construction725defines a plurality of gas flow passageways734.

Attention is directed to FIG.20. The ring construction725and the tube660are constructed and arranged to permit convenient manufacturing and assembly. In particular, the ring construction725and the tube660are configured to be secured together, such as by a mechanical engagement arrangement736. The mechanical engagement arrangement736is analogous to those detent/recess arrangements described above. In particular, the inner ring728includes a plurality of projections or detents738extending radially internally of the ring728. The wall662defines a recess740to accommodate the projections738. In this manner, the support frame656can conveniently and mechanically engage or snap into place with structural integrity with the wall662of the tube660.

The preformed insert660may be assembled as follows. The tube660, the ring construction725, and the first and second frame pieces681,682are provided, preferably through injection molding techniques. The media675is provided and preferably includes more than one layer; as shown inFIG. 18, the media675is two layers742,743of depth media.

The second frame piece682is oriented with respect to the tube660, such that the opening707defined by the wall700at the second end706is placed over an open end663of (FIG. 19) of the wall662of the tube660. The second frame piece682and the tube660are mechanically secured together through, for example, the mechanical engagement718of the projection720and recess722. The two layers742,743of media675are oriented over the screen710of the second frame piece682. After the depth media675is placed within the volume or pocket714, the first frame piece681is secured in position. In particular, the outer rim684is radially aligned with and inserted through the open end705defined by the wall700at the first end704. The first frame piece681moves with respect to the second frame piece682along the interior of the wall700, until the first and second frame pieces681,682are secured together in mechanical engagement through the detent698and recess696arrangement.

It should be noted that the first and second frame pieces681,682can be secured together with the fibrous bundle of media675trapped therebetween before the second frame piece682is secured to the tube660.

The ring construction725is secured to the tube660by sliding the end670of the tube through the interior of the inner ring728and snapping the pieces together through the mechanical engagement arrangement736. Of course, the ring725and the tube660may be secured together at any point during the assembly process.

In preferred arrangements, the assembled pre-formed insert650may then be secured to the remaining portions of the filter element420through, for example, molding techniques that are described further below.

InFIG. 21, a filter element800is shown in cross-section with the insert650installed therein. It should be understood that, other than the insert650, the filter element800is preferably constructed identically to the filter element420. As such, the element800includes the first stage coalescer filter media844, the second stage filter media construction846, a first end cap856, and an opposite, second end cap858. Because the element800includes the insert construction650, it includes tube660, media675, first frame piece681, second frame piece682, ring construction725, and two layers of depth media742,743, each as described above.

Also as described above with respect to the filter element420, the end cap856includes an inner, annular sealing portion864, which forms a seal, preferably a radial seal with portions of an inlet tube. The end cap858is also configured analogously to the end cap445ofFIG. 15, including a projection870, which forms a seal, preferably an axial seal with a service cover. The second stage media construction846preferably includes pleated media878extending between the end caps856,858. The pleated media878defines an open tubular interior879.

Attention is now directed toFIGS. 22 and 23, which depict an example molding technique that is usable to manufacture filter elements described herein. In many preferred arrangements, the insert construction (such as preformed insert446and preformed insert650) is assembled in advance, according to techniques described above. The preformed insert depicted inFIGS. 22 and 23is shown generally at900. The preformed insert900includes a frame construction902for holding coalescer media904. The preformed insert900also includes a tube or tapered wall906and a ring construction908.

Pleated media910is provided and formed in a ring or cylinder, around the preformed insert900. The pleated media910with the insert900is oriented over a mold912. Note that the mold912includes a platform or mount914. The frame construction902rests upon the mount914. Molten material for forming the end cap, such as polyurethane foam, is poured into the mold912in the volume916. The molten end cap material915is formed in the negative shape of the mold912. The end cap material915preferably rises as it cures and is allowed to penetrate the region691between, for example, the rim690and the outer rim684in the arrangement depicted in FIG.17. This permits the end cap material915to secure the coalescer media904to the resulting end cap918. The pleats of the pleated media910are also then secured to the resulting end cap918by being potted or molded into the end cap material915. As can also be seen inFIG. 22, the backstop920of the frame construction902also becomes molded within the end cap918. If desired, an outer liner922is placed around the outer perimeter of the pleats910and is molded with the end cap material915.

After the end cap918is formed, the assembly924is inverted and placed into a mold926. End cap material928, such as polyurethane foam, rests in the volume930. As the end cap material928cures, the pleats in the pleated media910are molded and fixed in place in the end cap material928to end up being potted within a resulting end cap932. Note that the ring construction908is oriented in a position spaced from the mold926and with a mold plug934adjacent thereto, such that the ring construction908does not become blocked with end cap material928.

VI. Principles Related to Size, Efficiency, and Performance; Materials

An arrangement utilizing principles described herein can be configured in a relatively small package, with efficient operation. For example, the first stage coalescer filter416/844is configured to have an upstream surface area of no more than 25%, usually no more than 10% of the upstream surface area of the second stage filter media418/846. In many applications, this percentage is much lower, typically 2% or less and often 1% or less. Typical percentages of the upstream surface area of the first stage coalescer filter416/844to the second stage filter media418/846are in the range of at least 0.1%, typically 0.2%-1%. For heavy duty engines (engines having a 12-15 liter piston displacement), the percentage is on the order of less than 0.5%, typically 0.25%. For medium duty engines (engines having a 6-9 liter piston displacement), the ratio is often less than 0.8%, for example about 0.4%. For light duty engines (engines having a piston displacement of less than 6 liters), the ratio is usually less than 1.5%, for example on the order of 0.8%.

It is foreseen that systems such as those depicted in the figures will be configured in relatively small overall packages. For example, overall sizes for the element420/800will have an outside diameter of no greater than 8 inches, and at least 3 inches, with a length of no greater than 15 inches, and at least 4 inches. For heavy duty engines, the size of the element420/800will be about 5.5 inches diameter and 11 inches long. For medium duty engines, the element420/800will be about 5 inches in diameter and 8 inches long. For light duty engines, the size of the element420/800will be about 4 inches in diameter and 6 inches long.

When selecting the size for the element420/800, the amount of filter media used in the element420/800is adjusted in order to maintain a desirable range of air velocities through the engine. In systems described herein, it is preferred that the face velocity across the first stage filter media418/844be maintained at a constant of 250-400 feet per minute. Similarly, it is preferable in systems described herein to maintain the face velocity across the second stage filter media418/846of no more than 1 foot per minute.

The amount of media for each of the first stage coalescer filter416/844and second stage filter media418/846are selected up to achieve efficient filtering, while limiting the amount of restriction. In systems described herein, the overall efficiency of the filter arrangement400is on the order of at least 80%, and typically 90-95%. By “efficiency”, it is meant the fraction of mass in the gas stream that is captured or trapped by the first stage coalescer filter416/844and second stage filter media418/846. The efficiency of the first stage coalescer filter416/844is usually at least 25%, in some cases no greater than 70%, typically 30-60%, for example 50%. The second stage filter media418/846preferably has a greater efficiency than the first stage coalescer media416, on the order of at least 70%, typically 80-90%.

Restrictions across the first stage coalescer filter416/844are on the order of 0.5 inch of water at the beginning of the filter life, typically 3-4 inches, and on the order of 5.0 inches of water at the end of the filter life. For the second stage filter media418/846, the restriction will be at least 0.5 inch of water (typically at the beginning of the filter life), and up to about 15 inches of water at the end of the life.

Usable Materials

The sealing portions480,864, and preferably, the entire end caps444,856preferably comprise foamed polyurethane. One example foamed polyurethane is described above. Another usable foamed polyurethane is as follows: BASF 36361R resin/WUC 3259T isocyanate, with processing conditions of: component temperatures of 75-95° F. for the resin and for the isocyanate. The mold temperature should be 120-140° F. The demold time should be 6 minutes. The compression deflection at 70° F., average 10+4/−3 psi; after heat aging 7 days at 158° F., +/−20% change from original deflection; at −40° F. cold temperature, 100 psi maximum average. The compression set, after heat aging 22 hours at 212° F., 15% maximum. The hardness should be 26 Shore A. The tensile strength should be 92 psi target. The elongation should be 120% minimum average. The tear strength should be 10 lb/in minimum average. The as molded density should be less than 30 lbs/ft3, for example, 23-28 lbs/ft3, and can be in the range of 10-24 lbs/ft3.

The housing402preferably comprises plastic, such as carbon filled nylon. The preformed inserts650/446are preferably injection molded from a synthetic resinous plastic material, such as DELRIN®, available from DuPont.

The media for the coalescer filter456/884preferably comprises polyester, depth media, as characterized above for media224. The media438/478for the downstream construction preferably comprises pleated media, as characterized above for media194.

In general, and in summary, the disclosure concerns an arrangement for use in separating a hydrophobic liquid aerosol phase, from a gas stream, during filtration of engine crankcase gases; the arrangement comprising: a first stage coalescer filter defining a flow passageway and including a nonwoven fibrous bundle extending across the flow passageway and having a first upstream surface area; and a second stage filter comprising pleated media positioned downstream from the nonwoven media of fibers of the first stage coalescer; the pleated media of the second stage filter having a second upstream surface area; the first upstream surface area being no more than 10% of the second upstream surface area; the arrangement characterized in that: the arrangement includes a first end cap (202,272,322,444,856) and a second end cap (254,274,324,445,858); the first end cap (202,272,322,444,856) including a central gas stream inlet aperture (206,272a,322a,468,864); the second stage filter (66,278,328,418,846) comprises a tubular construction of pleated media (194,278,328,434,878) extending between the first end cap (202,272,322,444,856) and the second end cap (254,274,324,445,858); the tubular construction of media (194,278,328,434,878) defining an open tubular interior (192,296,333,436,879); the central gas stream inlet aperture (206,272a,322a,468,864) of the first end cap (202,272,322,444,856) being in flow communication with the open tubular interior (192,296,333,436,879); the first stage coalescer filter (234,298,334,416,844) is oriented in extension across the gas stream inlet aperture (206,272a,322a,468,864); and the pleated media (194,278,328,434,878) of the second stage filter (66,278,328,418,846), the first end cap (202,272,322,444,856), the second end cap (254,274,324,445,858), and the first stage coalescer filter (234,298,334,416,844) are unitary in construction.

In some embodiments, the first upstream surface area is no more than 2% of the second upstream surface area. In some embodiments, the first upstream surface area is no more than 1% of the second upstream surface area. In general, the pleated media (278,434,878) has a length extending between the first end cap (272,444,856) and the second end cap (274,445,858); and the arrangement further includes: a tube (286,512,660) within the open tubular interior (192,296,436) oriented to direct fluid from the first stage coalescer filter (298,416,844); the tube including an imperforate section (287,513,663) extending a distance from the first end cap (272,444,856) of 33-95% of the length of the pleated media (278,434,878).

A frame construction (222,298,450,652) is secured to the first end cap; the frame construction including a first frame piece (230,550,681) and a second frame piece (232,552,682) fitted together to define a retaining pocket (242,560,714) therebetween; the nonwoven fibrous bundle of the first stage coalescer filter being oriented within the retaining pocket. The first frame piece (681) includes: a cylindrical wall (684) defining an open inner volume (685); and a porous grid (686) integral with the cylindrical wall (684) and extending across the inner volume (685) of the first frame piece; the second frame piece (682) includes: a tubular wall (700) defining an open inner volume (702); and a porous grid (708) integral with the tubular wall (700) extending across the open inner volume (702) of the second frame piece; the nonwoven fibrous bundle of the first stage coalescer filter being positioned between the first frame piece porous grid (686) and the second frame piece porous grid (708).

In some embodiments, the tube (512,660) includes a conical section (515,667); the conical section having a tapered wall (514,662) with an angle of taper of at least 1°; the tapered wall (514,662) including a first end (519,663) adjacent to the first stage coalescer filter and an opposite second end (521,670) adjacent to the second end cap (445,858); the tapered wall (514,662) defining a fluid passage (516,664).

In some embodiments, there is a support ring (725) centering the frame construction (652) within the open tubular interior (436); the support ring (725) including: an inner ring (728) secured to the tapered wall (662) adjacent to the second end (670) of the tapered wall (662); an outer ring (730) radially spaced from the inner ring; and a plurality of spokes (732) between the inner ring and the outer ring; the inner ring, outer ring, and spokes defining a plurality of gas flow passageways (734) to allow for the flow of gas from the fluid passage (664) of the tapered wall (662), around the second end (670) of the tapered wall (662), through the gas flow passageways (734), and into the pleated media (878).

In some embodiments, the second frame piece (552,682) includes an axial extension forming a ring (568); the first end cap (444,856) has an inner annular surface (472,864) comprising a polymeric material positioned to form a radial seal (484) with a housing construction, when the filter arrangement is operably positioned in a housing construction; the axial extension of the second frame piece (552,682) forming a ring (568) comprising a backstop (572,682) to the radial seal (484), when the filter arrangement is operably positioned in a housing construction.

In some embodiments, the inner annular surface (472,864) comprises a stepped construction498having a plurality of regions (501,502,503) of decreasing diameters. The second end cap (445,858) has an outer, axial projection (474,870) oriented to form an axial seal (476,530) with a housing construction, when the filter arrangement is operably positioned in a housing construction. The second end cap (445,858) includes a central aperture (255,290,507) in fluid communication with the second end (521,670) of the tapered wall (514,662).

In general, there is an insert construction (650) secured to the first end cap (856); the insert construction (650) including: a coalescer frame construction (652), a flow construction (654), and a support ring (656); the coalescer frame construction (652) and the support ring (656) being secured to the flow construction (654); the coalescer frame construction including a first frame piece (681) and a second frame piece (682); the first frame piece (681) including: a cylindrical wall (684) defining an open inner volume (685); a support grid (686) integral with the cylindrical wall (684) and extending across the inner volume (685) of the first frame piece (681); and an inner rim (690) spaced radially inwardly of and adjacent to the cylindrical wall (684); the inner rim (690) and the cylindrical wall (684) defining material flow passages (691) therebetween; the second frame piece (682) including: a tubular wall (700) defining an open inner volume (702); a support grid (708) integral with the tubular wall (700) extending across the open inner volume (702) of the second frame piece; and an axial extension forming a ring (568); the nonwoven fibrous bundle of the first stage coalescer filter being positioned between the first frame piece support grid (686) and the second frame piece support grid (708); the first end cap (856) having an inner annular sealing surface (864) comprising a polymeric material; the ring (568) of the second frame piece (682) comprising a backstop (572,682) to the inner annular sealing surface (864), when the filter arrangement is operably positioned in a housing construction; the flow construction (654) includes a tube (660) within the open tubular interior (879); the tube (660) including a tapered wall (662) including a first end (663) adjacent to the first stage coalescer filter (844) and an opposite second end (670) adjacent to the second end cap (858); the tapered wall (662) defining a fluid passage (664) therewithin; the tapered wall (662) having an angle of taper of at least 1°; and the support ring (725) centering the frame construction (652) within the open tubular interior (879); the support ring (725) including: an inner ring (728) secured to the tapered wall (662) adjacent to the second end (670) of the tapered wall (662); an outer ring (730) radially spaced from the inner ring; a plurality of spokes (732) between the inner ring and the outer ring; the inner ring (728), outer ring (730), and spokes (732) defining a plurality of gas flow passageways (734) therebetween to allow for the flow of gas from the fluid passage (664) of the tapered wall (662), around the second end (670) of the tapered wall (662), through the gas flow passageways (734), and into the pleated media (878).

In some embodiments, the first frame piece (681) and a second frame piece (682) are secured together by a detent and recess interlock (696,698); the second frame piece (682) and the tapered wall (662) are secured together by a detent and recess interlock (720,722); and the inner ring (728) is secured to the tapered wall (662) by a detent and recess interlock (738,740).

Preferably, there is a housing (52,402) defining an interior and having a gas flow inlet (58,405), a gas flow outlet (60,410), and a liquid flow outlet (62,412); the pleated media (194,344,434,878), the first end cap (202,272,322,444,856), the second end cap (254,274,324,445,858), and the first stage coalescer filter (234,298,334,416,844) forming a filter element operably oriented within the housing interior; the first end cap (444,856) having an annular surface (210,472,864) comprising a polymeric material form a radial seal (214,484) with the housing (52,402).

Preferably, the arrangement is used as part of a blow-by recovery system.

There is also provided a method of treating diesel engine blow-by gases; the method comprising steps of directing blow-by gases from a diesel engine to a coalescer filter; removing at least a portion of a liquid phase from the gases with the coalescer filter as a collected liquid; after said step of removing at least a portion of a liquid phase, directing the gases through a tubular media filter; filtering at least a portion of particulates from the gases with the tubular media filter, and after said step of removing at least a portion of the collected liquid phase, directing drainage of at least a portion of the collected liquid from the coalescer filter, along a flow construction arrangement in the interior of the tubular media filter, to an outlet.

In many embodiments, the step of directing drainage includes draining by gravity the collected liquid along a flow construction arrangement including an inner tube oriented within the interior of the tubular media filter. In many instances, the step of directing the gases through the tubular media filter includes directing the gases along the interior volume of the inner tube, around an end of the inner tube, and into a gas flow plenum between a volume outside of the inner tube and inside of the tubular media filter.

There is also provided a method of servicing a filter arrangement; the method comprising: removing a cover member from a body assembly; installing a filter element into the body assembly; the step of installing the filter element includes simultaneously installing a coalescer filter and a tubular media filter with a liquid flow construction arrangement; and securing the cover member to the body assembly.

In preferred methods, the step of installing includes forming a radial seal between the filter element and the body assembly. Also, in preferred methods, the step of installing includes installing a cylindrical extension of pleated media with a region of fibrous media oriented in a first end cap at one end of the extension of pleated media.

Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein.