WO2012135410A1

WO2012135410A1 - Flow straightener arrangement for use with air cleaner assemblies; methods of assembly and use; and, air cleaner assemblies with flow straightener arrangement

Info

Publication number: WO2012135410A1
Application number: PCT/US2012/031070
Authority: WO
Inventors: Akinobu YAMAYA; Junichi TESHIGAWARA; Hajime YAO; Shigeo Kato
Original assignee: Donaldson Company, Inc.
Priority date: 2011-03-31
Filing date: 2012-03-29
Publication date: 2012-10-04

Abstract

A flow straightener arrangement usable with an air cleaner assembly is described. The flow straightener, generally, comprises first and second permeable screen sections, spaced from one another. The screen sections can comprise portions of woven wire screen pieces. In an example depicted, one of the screen pieces is configured in a bowl-shape and the other is a flat piece positioned in extension across the bowl-shaped first piece to form the flow straightener. Methods of assembly and use are described, as well as systems having the flow straightener positioned therein.

Description

FLOW STRAIGHTENER ARRANGEMENT FOR USE WITH AIR

CLEANER ASSEMBLIES: METHODS OF ASSEMBLY AND USE: AND.

AIR CLEANER ASSEMBLIES WITH FLOW STRAIGHTENER

ARRANGEMENT

This application is being filed on 29 March 2012, as a PCT International Patent application in the name of Donaldson Company, Inc., a U.S. national corporation, applicant for the designation of all countries except the US, and Akinobu Yamaya, Junichi Teshigawara, Hajime Yao, and Shigeo Kato, all citizens of Japan, applicants for the designation of the US only, and claims priority to U.S. Provisional Application Serial Number 61/469, 917 filed March 31, 2011, the subject matter of which is incorporated by reference in its entirety.

Field of the Disclosure

The present disclosure relates to air cleaner assemblies and systems, for example of the type used to filter intake air for combustion engines. The disclosure specifically relates to flow straightener assemblies included within such systems, to stabilize filtered air flow being transferred from an air cleaner assembly through duct work that may include a mass air flow sensor, and then into an engine.

Example air flow straightener arrangements and methods of assembly are described.

Background

Air cleaner assemblies are generally used to filter air directed into the engine air intake, for example as combustion air, to internal combustion engine. Such engines can be used for example on a variety of vehicles and other equipment.

Many such air cleaner assemblies are used in association with mass air flow sensor arrangements. A mass air flow sensor is typically a sensor positioned downstream from filter cartridge arrangements used within an air cleaner assembly. The mass air flow sensor will typically be positioned in an air flow duct between the air cleaner and the engine. For good mass air flow sensor operation, it is desirable to have controlled variability in air flow through the duct in which the mass air flow sensor is positioned. That is, excessive and variable turbulence in air flow is undesired. To facilitate air flow consistency, it is sometimes desirable to position a flow stabilizer (sometimes called a flow straightener) downstream of any air filter cartridge within the air cleaner assembly and upstream of the mass air flow sensor.

It is desirable to provide advantageous and inexpensive mass air flow straighteners, to accomplish the desired results. Herein, example arrangements, methods, and techniques to accomplish this are provided.

Summary

According to the present disclosure, a flow straightener (or stabilizer) for use in an air flow duct of an air cleaner system is described. The flow straightener is typically configured to be positioned in a clean air duct between an air cleaner assembly and an engine air intake, in an air induction system for an internal combustion engine. The flow straightener can be characterized as comprising first and second permeable screen sections, positioned spaced from one another.

Typically, the spacing is at least 1 mm and not more than 30 mm, often at least 2 mm, and not more than 20 mm, usually 2-15 mm, inclusive.

It is noted that the flow straightener can be secured to the filter cartridge, for example at a downstream end of a filter cartridge, between the outlet flow from the cartridge and the mass air flow sensor. Thus, the flow straightener or stabilizer can form part of a filter cartridge. That portion can be removably mounted on the cartridge, or be permanently secured thereto. In examples, the flow straightener can be secured over an outlet flow face of a cartridge, or it can be positioned across an outlet flow aperture from a cartridge.

In an example depicted the first permeable screen section is a base or end portion of a bowl-shaped screen piece, that can be formed from a flat screen piece; and, the second screen section comprises a portion of a flat screen piece secured in position across an open end of the bowl-shaped piece.

Methods of assembly and preferred structural detail are provided.

Also disclosed are systems of use and example advantageous features. There is no specific requirement that a method, system, assembly, feature or technique as described herein, be applied with all the details of the example arrangements disclosed and described. Advantages can be obtained in alternate application, which differ in specific detail. Brief Description of the Drawings

Fig. 1 is a schematic depiction of an arrangement including an air cleaner assembly, a flow straightener, a mass air flow sensor and an engine system usable in or on equipment in accord with the present disclosure.

Fig. 2 is a schematic side cross-sectional view of a flow straightener constructed in accord with the principles described herein.

Fig. 3 is an enlarged fragmentary schematic view of an identified portion of

Fig. 2.

Fig. 4 is a schematic plan view of the flow straightener of Fig. 2.

Fig. 5 is a schematic depiction of an air cleaner system including a flow straightener in accord with the present disclosure.

Fig. 6 is a schematic, enlarged, fragmentary view of selected portions of the system depicted in Fig. 5.

Fig. 7 is an enlarged, schematic cross-sectional view of selected portions of the system of Fig. 5.

Fig. 8 is an enlarged schematic view of a selected portion of Fig. 7.

Fig. 9 is a schematic flow diagram schematically depicting assembly steps useable in the production of a flow straightener in accord with Figs. 2-4. Detailed Description

I. Air Cleaner Assemblies and Flow Straighteners Generally

Fig. 1 is a schematic depiction of an equipment system including an air cleaner assembly, engine system, mass air flow sensor system and flow straightener arrangement in accord with the present disclosure. In general, reference numeral 1,

Fig. 1 , indicates the equipment system. The equipment system 1 can be any equipment in which an air cleaner system is used. The equipment system 1 , for example, can be a vehicle such as an over-the-highway truck or bus. It can be a construction or agricultural equipment, mining equipment or another system. It can be a stationary system such as a generator system.

Referring to equipment system 1, at 2 is generally indicated an engine system for operation of the equipment of concern. The engine system 2 will generally comprise an internal combustion engine, for example a diesel engine. Combustion air intake for the engine system 2 is indicated generally at 3, with the air being directed to the intake 3 via duct system 4.

In general, it is preferred that air in the duct system 4 be filtered. Filtration is provided by an air cleaner assembly indicated generally at 8. A typical air cleaner assembly 8 comprises a housing 10 including a removable service access cover 11. Removably positioned within interior lOi of the housing 10 is positioned a serviceable air filter cartridge arrangement 13.

In operation, air enters housing 10 through air flow inlet 14, and is directed through cartridge arrangement 13, with filtering, before the air can enter the duct arrangement 4. Typically, the system comprising the air cleaner assembly 8 and duct system 4 will sometimes be referred to as the air induction system for the engine 2.

Any of a wide variety of arrangements can be used for the air cleaner assembly 8 and the cartridge arrangement 13. The air cleaner assembly 8 can include a safety or secondary cartridge if desired. When the term "air cleaner assembly" is used herein, without more, reference is meant generally to any assembly which will filter the air and which, typically, includes at least one filter cartridge (or cartridge arrangement) therein. Typically, the filter cartridge (or cartridge arrangement) is serviceable, i.e. it can be removed and be replaced with respect to the overall air cleaner assembly 8. Thus, as the filter cartridge 13 begins to load with dust during use, it can be removed to be refurbished or replaced.

Still referring to Fig. 1, positioned within duct arrangement 4 is mass air flow sensor 15. The mass air flow sensor (MAFS) is a sensor of a system that monitors air flow within duct 4 from air cleaner assembly 8 to engine system 2. Signals of measurements from the mass air flow sensor 15 are directed to the control arrangement 16 which can be configured to make adjustments in operation of the engine (for example fuel adjustments; sparking adjustments, etc.) based on detected air flow within the duct arrangement 4.

Mass air flow sensor equipment is generally commercially available from such supplies as Hitachi Automotive Systems, Harrodsburgh, KY 40330; and AC Delco, Grand Blanc, MI 48439.

For proper mass air flow sensor operation, it is desirable to provide that air flow within duct arrangement 4, between the air cleaner 8 and engine 2 is not subject to substantial, uncontrolled, fluctuations or inconsistency in operation. That is, the mass air flow sensor 15 is typically tuned for proper operation of the engine, for example during assembly or installation. It is desired to ensure that the air flow past the sensor 15 does not vary in a manner that creates undesirable fluctuations in mass air flow sensor operation, or the desired effects of the MAFS system will not be fully achieved. To accomplish this, in some systems, a flow straightener (or stabilizer) is positioned in the air flow between the cartridge arrangement 13 and the mass air flow sensor 15. In the equipment system 1 of Fig. 1, such a flow

straightener is indicated, generally, at reference numeral 20. In general terms, the flow straightener 20 is a system through which air passes as is directed into or through the duct arrangement 4 and past the mass air flow sensor 15. The effect of the flow straightener 20 is to stabilize and straighten the air flow in the duct 4, for good mass air flow sensor operation. In other words, the flow straightener 20 helps ensure flow past the mass air flow sensor 15, within a duct arrangement 4, is a sufficiently stable air flow, without undesirable levels of fluctuation therein that could undesirably effect proper mass air flow sensor operation.

In accord with the present disclosure, an improved flow straightener 20 is provided along with techniques for its assembly and use.

II. An Example Improved Mass Air Flow Sensor, Figs. 2-4 In Figs. 2-4, a flow straightener assembly or flow straightener 25 is depicted, usable as flow straightener 20 in an equipment system 1 in accord with Fig. 1.

Referring to Fig. 2, the flow straightener 25 generally has at least two (first and second) layers of permeable screen sections 26, 27. For the particular straightener 25 depicted, the screen sections 26, 27 are positioned spaced from one another, in the air flow stream. For the assembly depicted in Fig. 2, a typical air flow direction is indicated by arrow 29, although an alternate (opposite) direction of use is feasible.

In general, each of the two screen sections 26, 27 comprises a screen or flow straightening element, which will extend across duct arrangement 4, Fig. 1 , in use. Extending around an outer perimeter 25p of straightener 25 is positioned a perimeter rim 30. The rim 30 can be used as a mounting rim, to help secure the flow straightener 25 in position for use.

In the portion of the flow straightener 25 in which the screen sections 26 and 27 are spaced from one another, which is the majority of extension across the duct arrangement 4, the screen sections 26, 27 are typically spaced by at least 1 mm, usually at least 2 mm, typically not more than 30 mm, usually not more than 20 mm and often an amount within the range of 2-15 mm, inclusive, although alternatives are possible.

Typically, the screen material in each of screen sections 26, 27 is flat and uncontoured. Although one or both may be a portion of a screen piece that is contoured.

Typically, each of the screen sections 26, 27 has a total perimeter area of at least 4,000 sq. mm, typically at least 5,000 sq. mm; and, often an amount within the range of 5,000-25,000 sq. mm, typically 5,000-15,000 sq. mm. Although alternate sizes are possible, such perimeter sizes are typical.

In Fig. 2, an example dimension of usable arrangement for a specific system described herein is provided. In Fig. 2, dimension AA = 101.5 mm.

Typically, a characteristic of preferred flow straighteners in accord with the present disclosure, is that they include no filter media, between the spaced screen sections 26, 27. That is, there is preferably no permeable media such as a filtration media, positioned within the space 25s between the screen sections 26, 27. Also, preferably (except for an outer perimeter wall section discussed below) there are no spacers or obstructions to airflow between the screen sections 26, 27. That is, typically, and preferably, region 25s, which corresponds to the space between screen sections 26, 27, is an open, empty, space.

Attention is now directed to Fig. 3, in which an enlarged fragmentary view of selected and indicated portion of flow straightener 25, Fig. 2, is provided. Referring to Fig. 3, it can be seen that in the straightener depicted, layers or screen sections 26, 27 are maintained spaced by a sidewall or perimeter wall section 33. For the particular flow straightener 25 depicted, the sidewall or perimeter wall section 33 is formed from a portion of a screen piece that also forms one of the screen sections

26, 27. That is, perimeter wall section 33 is integral with one of screen sections 26,

27, in a typical, preferred, straightener 25, although alternatives are possible. For the particular example flow straightener 25 depicted, screen section 26 and side wall

33 are integral with one another, i.e. they are both formed as sections of the same screen piece. Still referring to Figs. 2-4, for the example flow straightener 25, the screen sections 26, 27 are formed, respectively, from two screen pieces 36, 37 that are secured to one another.

Referring to Fig. 3, at perimeter flange or rim section 34, screen pieces (36, 37) that make up screen sections 26 and 27 respectively are positioned adjacent to one another and secured together. Outer securing or covering rim or ring 38 is positioned around and outer flange or rim section 34, to form rim 30 by securing the assembly together and to protect the outer rim definition.

In Fig. 3, some example dimensions are as follows: AB = 1.8mm; AC = 5.8 mm; AD = 0.4 mm; AE = 108 mm diameter; and, AF = 103 mm diameter.

Attention is now directed to Fig. 4, in which a plan view of the flow straightener 25 is depicted. The view in Fig. 4 is generally toward screen section 27, of screen piece 37. In Fig. 4, some example dimensions are indicated as follows: AG = 103 mm diameter; and, AH = 108 mm diameter.

Referring to Fig. 4, it can be seen that for the example flow straightener 25 depicted, an outer perimeter definition is generally circular. This is typical, since a typical duct 4, Fig. 1 , that is positioned between an air cleaner assembly and engine will have a generally circular interior cross-section. It is noted that in alternate systems, however, the principles of the present disclosure can be implemented with flow straighteners that do not have circular outer perimeters.

A variety of materials can be used for the sections 26, 27, and screen pieces 36, 37 and there is no specific requirement that the same material be used for both screen pieces 36, 37. Typically the same types of material will be used for both sections 26, 27 (and pieces 36, 37), the material comprising a formable mesh screen, such as woven wire screen. Typically a stainless steel wire mesh screen will be used. An advantage to such materials is that they are relatively robust, and they can be readily formed through cutting and bending (or forming) operations, to have the shapes indicated in Figs. 2 and 3. In Fig. 4, an indication that the screen section 27 is formed from a woven wire screen is provided at 39.

Typically, the material chosen as pieces 36, 37, and to include screen sections 26, 27, is a sufficiently flexible material to form the shapes desired, but which is also capable of retaining a formed shape sufficiently to substantially maintain the intended shape depicted, in use. A stainless steel woven wire screen would typically be adequate. In a typical assembly, each screen section comprises woven wire screen having a total thickness of not greater than 1.5 mm, typically not greater than 0.7 mm and usually at least 0.1 mm, for example, within the range of 0.1-0.7 mm. The screen will typically have 5-20 pores and wires per cm in each direction. Typically, the wire diameter is not greater than 0.4 mm.

It is noted that alternate materials can be used.

Typically, the outer perimeter ring 38 comprises a metal piece, such as a stainless steel piece, folded or pinched (for example rolled) over joint 34

circumferentially around the entire flow straightener 25. Usable material for the rim 38 is a thin flexible stainless steel piece, having a thickness on the order of 0.2-0.8 mm, inclusive.

In general terms, then, flow straightener according to the present disclosure, typically includes two, spaced, screen sections, each typically flat. The screen section are typically spaced apart a distance within the range of 2 -30 mm typically 2-15 mm, and each is generally sized to extend substantially across a flow duct in which the flow straightener is positioned. Thus, for a typical use, each screen section will have a perimeter area typically at least 4,000 sq. mm, usually at least 5,000 sq. mm and often within the range of 5,000-15,000 sq. mm depending on the system. Each screen section will typically comprise a woven wire screen, although alternatives are possible. In the example assembly depicted, one screen section is a recessed bottom of a bowl-shaped screen piece, with the second screen section comprising a portion of a second screen piece extending across the first (bowl- shaped) screen piece.

A more detailed discussion of the formation of the flow straightener 25 is provided herein below in Section IV. Prior to that discussion, an example system of use is described.

III. An Example System for Use with Flow Straightener 25, a Truck Engine

Intake System

In Fig. 5, an example air cleaner system is depicted for use of flow straightener in accord with the present description. The air cleaner system is indicated generally, in Fig. 5, at 50. The air cleaner system 50 includes a housing 51 with the removable access cover 52 shown secured in place by latches 53. An air inlet to the housing 50 is indicated generally at 54.

At 57 an outlet tube or duct for filtered air leaving housing 51 is depicted. The tube or duct 57 is also a mounting tube or duct for a mass air flow sensor arrangement indicated generally at 58. Air from the tube 57 and mass air flow sensor arrangement 58 passes into outlet plenum 60 and via tube 61 it is directed to the engine air intake for the equipment involved.

In general, the flow straightener 25, Figs. 2-4, would be mounted in the assembly 50, typically between, within or adjacent to (i.e. under) an end of tube 57, adjacent housing 51. This will be understood by reference to Figs. 7 and 8, discussed below.

Before, turning to Figs. 7 and 8, attention is directed to Fig. 6, which is an exploded view of selected portions of air cleaner system 50. Referring to Fig. 6, access cover 52 with latches 53 thereon is depicted. At 65 is depicted a gasket, to be positioned between the access cover 52 and a remainder of the housing 51 , Fig. 5. Also depicted is an evacuation valve arrangement 66 by which water or other material which flows into the interior of the housing that is not directed into a filter cartridge 70 can be evacuated from an interior of access cover 52.

In Fig. 6, a main filter cartridge 70 for the air cleaner assembly or system 50 is depicted. The cartridge 70 for the example depicted is generally in accord with the arrangements described in WO 2000/50149 and/or in WO 2005/063361, incorporated herein by reference. The cartridge 70, then, comprises a media pack 71 which, in the example depicted, can be characterized as a coiled strip of filter material comprising a fluted sheet secured to a facing sheet, and coiled with the facing sheet directed outwardly. The cartridge includes an upstream flow face 72 and an opposite downstream flow face 73, with the flutes extending therebetween. Selected flutes are open at the upstream flow face 72 and closed to the downstream flow face 73, and other flutes are open at the downstream flow face 73 and closed at the upstream flow face 72, to provide a filtration system sometimes referred to as "z- filter media." Such filtration arrangements are described in detail in WO

2005/107924, incorporated herein by reference.

At 75, a housing seal arrangement is depicted, by which the cartridge 70 is removably sealed within housing 51. The particular housing seal arrangement 75 depicted comprises an outwardly directed radial seal. That is, a perimeter seal 76 around an end of the cartridge 70, seals against a surrounding annular portion of the housing 51, when the cartridge 70 is installed.

At 77, an upstream end ring is positioned, to facilitate gripping the cartridge 70 during installation and removal.

A variety of alternate air filter cartridge arrangements can be used with the principles according to the present disclosure. For example, stacked z-filter arrangements such as described in WO 2006/017790 and WO 2006/076479 can be used. However, the principles can be applied with a variety of other filter systems that do not use z-filter type media at all. For example, flow straighteners in accord with the present disclosure can be used in arrangements in which a pleated media is used in a cylindrical form, as for example, described in U.S. 6,955,701; or, in a somewhat conical form, as for example, described in WO 2004/039476 and WO 2006/026241. Further flow straighteners can be used in systems in which media configurations in accord with U.S. 7,097,694 or media configurations in accord with U.S. 2010/0186353 is used. Generally, the specific configuration filter media within the air cleaner assembly is a feature that can be varied widely, with principles according to the present disclosure, since the flow straightener is typically positioned downstream from the filter cartridge, and often is not included within the air cleaner assembly itself. However it is noted that the air configuration of the air cleaner and configuration of the media may be variable that relates to the stability of air flow entering, or within, the downstream duct in which the flow straightener is positioned. Thus, for example, certain media configurations may be subject to great air flow variability problems, in the absence of the flow straightener.

Attention is now directed to Fig. 7, which shows an enlarged fragmentary cross-sectional view of a portion of Fig. 5, and in particular a portion involving tube 57. Here, the upper plenum or chamber 60 is seen with outlet 61 thereon. The flow straightener 25 is generally positioned at an inlet end 57i of tube 57. It is secured in place by having a portion of rim 30 positioned underneath a portion 57r of tube 57. Tube 57 can be secured in placed by bolts, clamps, vibration welding or by other means, as desired.

In Fig. 8, an enlarged schematic view of selected portion of Fig. 7 is depicted. At 25 the position for the flow straightener 25 can be seen.

IV. Assembly

A particularly advantageous process for construction of the depicted flow straightener 25 can be understood from reference to the flow diagram of Fig. 9.

Referring to Fig. 9, in the flow diagram, steps 9A-9F are depicted

schematically. It is not meant to be indicated that steps 9A-9F are fully

independently conducted, or that alternative steps or an alternative order of steps cannot be conducted in some instances. However, from an understanding of the flow diagram of steps 9A-9F, one can understand generally, the preferred production of a flow straightener having features generally in accord with flow straightener 25.

In general terms, construction of a flow straightener in accord with the present disclosure relates to conducting a method of positioning two screen sections, each typically relatively flat, spaced from one another by a distance chosen, typically, from within the range of 1-30 mm, usually 2-20 mm. Typically, the screen sections are positioned with no media therebetween, along a central section thereof, and preferably with no obstructions therebetween. Thus, typically the screen sections define an open interior and each is spaced from one another by a perimeter construction. A typical example preferred screen assembly, is one in which an outer perimeter or sidewall is formed from one of two screen pieces, from which the two screen sections are formed. The assembly method described in Fig. 9, is for construction of such an arrangement.

Referring to Fig. 9, at 9 A is depicted a formed die 100 positioned with a screen piece 36 thereon. The die 100 includes a cavity or form 101 configured for desired shaping of screen piece 36 as used in flow straightener 25. Typically, in operation, the screen that forms screen piece 36 will have been a flat piece extending across cavity 101, that is depressed into the cavity 101, for example in a metal forming operation, to generate a piece shaped as depicted at 105. That shape is one in which piece 36 is configured with: central screen section 36, and sidewall 33, typically also with perimeter radially outwardly projecting perimeter flange section 36p. When in the form in Fig. 9 at step 9 A, screen piece 36 can be characterized as having a "bowl" shape or as a "bowl-shaped" screen section.

In Fig. 9, at 9B, a piece of screen 106 used to form screen section 27 (of piece 37) in a resulting flow straightener 25, Figs. 2-4 is shown positioned over screen piece 105 resting on flange 36p. In the example depicted, screen piece 106 is shown with a perimeter 106p folded downwardly, although alternatives are possible.

It is noted that in the assembly of the flow diagram, Fig. 9, as viewable in Fig. 9B, for the preferred assembly of flow straightener 25, no media is positioned between screen pieces 36, 37, in the region of sections 26, 27 and no spacer, obstruction or item is positioned therein or therebetween.

Attention is now directed to Fig. 9 at 9C. Here, a step of securing pieces 105, 106 in the region of perimeter flange 36p is shown at 110. For the typical preferred screen materials, such as stainless steel screen, the attachment process or step at 110 can be a welding process, if desired.

In Fig. 9 at 9D, trimming the resulting arrangement from step 9C is shown.

Variations in the trimming can be conducted. The particular trimming depicted is conducted to trim excess portions of screen indicated generally at 115, from the combination. This will leave a construction having a perimeter rim section 34, at which each screen piece 36, 37 can be characterized as having a peripheral, perimeter, radially outwardly extending rim or flange; the screen pieces 36, 37 joining or abutting at the flanges (rims).

Referring to Fig. 9 at 9E, the result of the trimming operation, is a combination comprising screen piece 37 and screen piece 36 secured to one another, forming screen sections 26, 27 secured to one another and held spaced apart by outer sidewall section 33 of piece 36. The combination, again, comprises an outer perimeter flange or screen rim 34 where at the screen pieces 36, 37 are secured to one another.

In Fig. 9, at 9E, the combination 120 of screen pieces 36, 37 described is shown with a non-porous rim piece 126 being folded thereover.

In Fig. 9, step 9F, the completed flow straightener 25 is depicted, with the perimeter defined by rim piece 126.

Referring to Fig. 9, it is noted that metal piece 126 can be formed as a circular ring, into which a combination of screen pieces 36, 37 is positioned with rolling or folding over a portion of piece 126. Alternatively, piece 126 can be a strip that is folded or rolled over the flange 34, as it is circumferentially positioned.

General Observations

Herein, in the drawings, a specific example of a flow straightener is depicted.

It is noted that a flow straightener can be varied from the detail shown in the drawings, and remain in accord with the present disclosure. Further, it is noted that not only can a specific construction be varied from the present disclosure, but also steps of assembly, methods of use and systems of use can be varied. The drawings depicted are therefore intended to be exemplary of applications of the principles of the present disclosure, and not otherwise limiting.

According to an aspect of the present disclosure, a flow straightener is provided for use in an air flow duct in an air cleaner system. The flow straightener is particularly well configured to be positioned in an air flow duct with a location downstream from a filter cartridge arrangement of an air cleaner and upstream from a mass air flow sensor. In general terms, the flow straightener comprises a first permeable screen section and a second screen section, with the first permeable screen section being secured spaced from the second permeable screen section.

Typically, the flow straightener includes no permeable media therein, between the first and second permeable screen sections. Also, typically there is no obstruction to gas flow position between the first and second permeable screen sections.

In an example assembly depicted, the first permeable screen section comprises a recessed base or end of a bowl-shaped screen piece. Thus, the bowl- shaped screen piece has a sidewall integral with the base, formed from the same screen piece. Typically, with such an assembly, the first permeable screen section is secured within the flow straightener and is spaced from the second permeable screen section, by the (permeable) sidewall. The permeable sidewall can be characterized as a "perimeter sidewall" of the first permeable screen section, (or by similar terms) under such circumstances.

Typically, the first permeable screen section is positioned from the second permeable screen section by a distance of at least 1 mm, typically at least 2 mm, and in typical application, by a distance of not greater than 30 mm, usually no greater than 20 mm. A typical example assembly, would be one in which the first screen section is positioned spaced from the second screen section by a distance within the range of 2-15 mm, inclusive.

In an example assembly depicted, both the first permeable screen section and the second permeable screen section are flat and non-contoured, indeed each is a typically a flat section of woven wire screen.

Typically, the perimeter area of the first permeable screen section is at least 4,000 sq. mm, typically at least 5,000 sq. mm, often not more than 20,000 sq. mm, and often an amount within the range of 5,000-15,000 sq. mm, inclusive, although alternatives are possible. Similarly, typically the second permeable screen section has a perimeter area of at least 4,000 sq. mm, typically at least 5,000 sq. mm and often a size within the range of 5,000-15,000 sq. mm, inclusive, although

alternatives are possible. In an example assembly depicted, each one of the first permeable screen section and the second permeable screen section is generally circular in perimeter definition, although alternatives are possible.

When the first screen section comprises an end or base section of a bowl- shaped screen piece, typically that screen piece is formed to have an end (or base) section integral with a perimeter sidewall portion formed by the same screen piece.

In an example assembly depicted, each of the first and second screen sections is configured with a rim section that generally comprises a radially outwardly directed rim from a remainder of the screen piece. Typically, the screen pieces are secured to one another, by having the rim sections engaged, with securing, for example by welding. The rim section can be provided with a cover thereover, for example a non-porous metal piece, such as a stainless steel piece, folded or rolled over the perimeter, to define a mounting ring for the flow straightener.

Typically, again, the first screen section and the second screen section, each comprise portions of a woven wire screen such as a stainless steel metal wire or screen. Typically each has a thickness within the range 0.1-1.5 mm, although alternatives are possible. Also, typically each has a wire/pore population such that in directions parallel to wires, each screen piece in which a screen section is formed, has a pore population on the order of 5-20 per cm, and a wire population on the order 5-20 per cm, with wire diameter typically under 0.4 mm.

Also, according to the present disclosure, an alternate characterization of a flow straightener is provided in which the flow straightener comprises a first porous screen having a bowl-shape defining an end section and a sidewall section; and, the second porous screen piece secured to the first screen piece and positioned, with a section thereof spaced from the end section of the first screen piece by the sidewall of the first screen piece. With such an assembly, typically the second portion screen piece is a flat screen piece. The assembly can have the various features as characterized previously herein.

Also, according to the present disclosure, an air cleaner system is described. The air cleaner system includes a filtered air duct having mass air flow sensor therein. The duct is typically positioned downstream from an air cleaner assembly. The duct typically has a cross-sectional within the range of 4,000 sq. cm - 15,000 sq. cm, and typically has a circular cross-section, although principles can be practiced with alternate shapes and sizes of duct.

In general, a flow straightener according to the previous characterizations is positioned with spaced first and second screen sections extending across the air flow duct at a location upstream from the mass air flow sensor, and typically downstream from a filter cartridge arrangement of the air cleaner.

Also, according to the present disclosure, a method of forming a flow straightener for use in an air flow duct of an air cleaner system is described. The method generally involves securing first and second permeable screen sections, spaced from one another, typically by a distance of at least 1 mm, usually at least 2 mm, and typically not more than 30 mm, usually not more than 20 mm. In a preferred method, a first screen piece is configured in a bowl-shape, with a recessed bottom (or end) section and a perimeter sidewall, and a second screen piece is positioned in spaced relation to the first screen piece, i.e. in extension across an open end of the bowl.

Typically the first screen piece is formed into the bowl-shaped section from a flat screen piece, and the recessed bottom (end) section of the first screen pieces is flat. The step of securing the two screen pieces, is typically through welding.

In a preferred assembly, the second screen piece is a flat screen piece secured to the first screen piece.

The method can be practiced with a step of forming perimeter rim sections in each the two screen pieces that adjoin one another and extend radially outwardly from the configuration. A non-porous covering ring can be positioned around and over the perimeter screen rims of the first and second screen pieces. Typically, the non-porous rim will be a metal rim, folded or rolled over the perimeter rim of the screens.

Typically, the screen sections are configured within the assembly spaced within the range of 2-30 mm, typically 2-25 mm, often 2-15 mm, from one another.

It is noted that there is no specific requirement that the application, principles, features, techniques and methods according the present disclosure, be practiced with all the detail features disclosed in the drawings and provided in the description. Advantages can be obtained with application of principles less specifically detailed.

Concluding Summary

According to the present disclosure, a flow straightener for use with an air cleaner system is provided. The flow straightener can, for example, be configured to fit within an air flow duct of an air cleaner system. The straightener can, in accord with above principles, be configured in accord with the following characterizations:

A flow straightener for use in an air cleaner system (for example in an air flow duct); the flow straightener comprising:

(a) a first permeable screen section; and,

(b) a second permeable screen section;

(i) the first permeable screen section being spaced from the second permeable screen section.

A flow straightener according to characterization 1 above wherein:

(a) the flow straightener includes no permeable media therein, between the first and second permeable screen sections. A flow straightener according to any one (at least one) of characterizations 1 and above 2 wherein:

(a) the first permeable screen section is supported spaced from the

second permeable screen section by a perimeter side wall.

A flow straightener according to characterization 3 above wherein:

(a) the perimeter sidewall is porous.

A flow straightener according to any one (at least one) of characterizations 3 and 4 above wherein:

(a) the perimeter sidewall comprises a screen section integral

with the first permeable screen section.

A flow straightener according to any one (at least one) of characterizations 1

5 above wherein:

(a) the first permeable screen section is positioned spaced from the second permeable screen section by a distance of at least 1 mm.

A flow straightener according to any one (at least one) of characterizations 1

6 above wherein:

(a) the first permeable screen section is positioned spaced from the second screen section by a distance of not more than 30 mm.

A flow straightener according to any one (at least one) of characterizations 1

7 above wherein:

(a) the first screen section is positioned spaced from the second screen section by a distance within the range of 2-20 mm, inclusive.

A flow straightener according to any one (at least one) of characterizations 1

8 above wherein:

(a) the first permeable screen section has a perimeter area of at least 4000 sq mm; and,

(b) the second permeable screen section has a perimeter area of at least 4000 sq mm. A flow straightener according to any one (at least one) of characterizations 1-

9 above wherein:

(a) the first screen section has a perimeter area of at least 5,000 sq mm; and,

(b) the second screen section has a perimeter area of at least 5000 sq mm.

A flow straightener according to any one (at least one) of characterizations 1-

10 above wherein:

(a) the first screen section has a perimeter area of within the range of 5000 -15,000 sq mm, inclusive; and,

(b) the second screen section has a perimeter area of within the range of 5000 -15,000 sq mm, inclusive.

A flow straightener according to any one (at least one) of characterizations 1-

11 above wherein:

(a) the first screen section comprises an end section of a bowl-shaped screen piece; the first screen section being bordered at a perimeter thereof by an integral wall section of the bowl-shaped screen piece; and,

(b) the second screen section comprises a portion of a flat screen piece.

A flow straightener according to any one (at least one) of characterizations 1-

12 above wherein:

(a) the first screen section is a portion of a first screen piece having a first perimeter rim section; and,

(b) the second screen section is a portion of a second screen piece having a second perimeter rim section;

(i) the first and second perimeter rim sections being secured against one another.

A flow straightener according to any one (at least one) of characterizations 1 -

13 above including:

(a) a perimeter rim; (i) the first and second perimeter rim sections being positioned within the perimeter rim.

A flow straightener according to characterizations 14 above wherein:

(a) the perimeter rim comprises a non-porous metal piece folded over the first and second, perimeter rim sections.

A flow straightener according to any one (at least one) of characterizations 1- 15 wherein:

(a) the first screen section comprises a portion of a wire screen having a thickness within the range of 0.1 -1.5 mm; and,

(b) the second screen section comprises a portion of a wire screen having a thickness within the range of 0.1 -1.5 mm.

A flow straightener for use in an air flow duct of an air cleaner system; the flow straightener comprising:

(a) a first porous screen piece having a bowl shape defining an end

section and a sidewall section; and,

(b) the second porous screen piece secured to the first screen piece and positioned spaced from the end. section of the first screen piece by the sidewall section of the first screen piece.

A flow straightener according to characterization 17 above wherein:

(a) the second porous screen piece is a flat screen piece.

An air cleaner system including:

(a) a filtered air duct having a mass air flow sensor therein; and,

(b) a flow straightener according to any one (at least one) of

characterizations 1-18 above positioned with spaced first and second screen sections extending across the air flow duct at a location upstream from the mass air flow sensor.

A flow straightener in accord with any one of claims 1-18 secured to a filter cartridge. Also, according to the above discussion and principles, methods of constructing flow straighteners are described. The methods can be conducted in accord with the general descriptions above and/or in accord with the following claims.

Claims

What is claimed:

A method of forming a flow straightener for use in an air cleaner system; the method including a step of:

(a) securing first and second permeable screen sections spaced from one another by a distance of at least 1 mm and not more than 30 mm.

A method according to claim 1 wherein the step of securing comprises:

(a) securing a second screen piece in covering relation to a first screen piece;

(i) the first screen piece having a bowl-shaped portion with a recessed bottom section and a perimeter sidewall.

A method according to claim 2 including a step of:

(a) forming the first screen piece into the bowl-shaped portion by

deforming a flat screen piece.

A method according to any one of claims 2 and 3 wherein:

(a) the recessed bottom section of the first screen piece is formed as a flat section.

A method according to any one of claims 2-4 wherein:

(a) the step of securing comprises welding.

A method according to any one of claims 2-5 wherein:

(a) the step of securing a second screen piece in covering relation to a first screen piece, comprises providing the second screen piece with a flat section of screen in extension across the bowl-shaped portion of the first screen piece.

A method according to any one of claims 2-6 wherein:

(a) the first screen piece is formed with a perimeter rim section; and (b) the step of securing comprises securing the second screen piece to the perimeter rim section of the first screen piece.

8. A method according to any one of claims 2-7 wherein:

(a) the step of securing includes providing a perimeter screen rim in each of the first and second screen pieces whereat the first and second screen sections are secured to one another; and,

(b) the method includes a step of positioning a covering rim around, and over, the perimeter screen rim of the first and second screen pieces.

9. A method according to claim 8 wherein:

(a) the step of providing a covering rim comprises folding a non-porous, metal piece over the perimeter screen rim.

10. A method according to any one of claims 2-9 wherein:

(a) the step of securing comprises securing the first screen piece to the second piece with no filtration media occupying a space between the recessed bottom section of the first screen piece and a portion of the second screen piece spaced therefrom by a sidewall section of the bowl-shaped portion.

11. A method according to any one of claims 1-10 wherein:

(a) the step of securing comprises securing the first screen section spaced within the range of 2-20 mm, inclusive, from the second screen section.