The present disclosure relates to the field of pneumatic systems for Rail road applications. In particular, the present disclosure relates to an air filter that includes a dust separation and discharge mechanism. BACKGROUND
[02] Background description includes information that may be useful in understanding
the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[03] Pneumatic systems such as pneumatic brakes used on rail road vehicles typically
use atmospheric air, which is compressed and delivered in controlled manner to different assemblies to actuate them. As is evident, the air that is sucked in from atmosphere needs to be filtered to remove various contaminants present in the air to avoid their detrimental effect on pneumatic systems. Contaminants, besides including dust present in atmosphere, also includes water from condensation of water vapors present the air as well as oil that may be carried over from compressor used to compress the air. Contaminants, including dust and water, can be injurious to pneumatic systems and its assemblies on account of their abrasive and corrosive actions which may cause premature failure, and therefore need to be removed before air is delivered to various assemblies in the pneumatic system.
[04] Therefore, pneumatic systems typically use filters that remove the contaminants
from air used in the system. This can be done using a number of different techniques, for example using a media that traps particulates, using a membrane that only allows air to pass through, and using cyclonic action to separate dust, to name a few. However, using a membrane such as paper is most commonly used method where the filter incorporates a pleated paper to accommodate paper with large enough surface area in a compact manner. As air with contaminants passes through the pater, contaminants are retained with the paper and clean air passes through.
[05] As is evident, over a period the paper filter element shall get clogged with the
contaminants resulting in resistance to air flow, and therefore the filter element needs to be cleaned/replaced periodically. In order to prolong life of the filter element, it is usual to employ pre-filters to remove large sized contaminants to prevent their reaching the filter

element and choking it, thereby enhancing life of the filter element between cleaning/replacements.
[06] However, such pre-filters add another assembly with associated requirement of
periodic maintenance. Besides, pre-filters add to pressure drop, as air has to pass through an additional filtering medium.
[07] It would, therefore, be advantageous if an arrangement for pre-filtering the air
could be integrated with the air filter itself. It would be further advantageous if such pre-filtering the air could be done without having to pass the air through a filtering media so as to avoid pressure drop.
[08] There is therefore a need in the art to provide an improved air filter assembly that
includes pre-filtering without any significant drop in pressure.
[09] All publications herein are incorporated by reference to the same extent as if each
individual publication or patent application were specifically and individually indicated to be
incorporated by reference. Where a definition or use of a term in an incorporated reference is
inconsistent or contrary to the definition of that term provided herein, the definition of that
term provided herein applies and the definition of that term in the reference does not apply.
[010] In some embodiments, the numbers expressing quantities of ingredients,
properties such as concentration, reaction conditions, and so forth, used to describe and claim certain embodiments of the invention are to be understood as being modified in some instances by the term “about.” Accordingly, in some embodiments, the numerical parameters set forth in the written description and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by a particular embodiment. In some embodiments, the numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of some embodiments of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable. The numerical values presented in some embodiments of the invention may contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.
[011] As used in the description herein and throughout the claims that follow, the
meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.

[012] The recitation of ranges of values herein is merely intended to serve as a
shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.
[013] Groupings of alternative elements or embodiments of the invention disclosed
herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description of all Markush groups used in the appended claims.
OBJECTS OF THE INVENTION
[014] A general object of the present disclosure is to provide an improved air filter with
enhanced life of the associated filter element between maintenance.
[015] An object of the present disclosure is to providean improved air filter that
additionally pre-filter the air to enhance life of the filter element between maintenance.
[016] Another object of the present disclosure is to provide an improved air filter that
does not result in significant increase in pressure drop due to pre-filtering.
[017] Another object of the present disclosure is to provide an improved air filter that
that enables easy and quick removal/ discharge of contaminants trapped at pre-filtering stage.
[018] Another object of the present disclosure is to provide an improved air filtration by
channelizing the incoming air at an angle so as to separate the bigger foreign particles before
entering the filter element
[019] Yet another object of the present disclosure is to provide a separation plate so
separate the already filtered dust to get mixed with fresh incoming air to get better life of the
filter element

[020] Yet another object of the present disclosure is to provide an air filter assembly that
incorporates air filter for one or two or more independent air circuits of a pneumatic brake
system.
[021] Still another object of the present disclosure is to provide an improved air filter
that is compact and cost effective.
[022] Still another object of the present disclosure is to provide an improved air filter
that enables ease of periodic maintenance by minimum and easy removal of parts.
SUMMARY
[023] Aspects of the present disclosure relate toan air filter assembly for filtering air in a
pneumatic brake system. In an aspect the disclosed air filter assembly incorporates a pre-filter that traps contaminants
[024] In an aspect, the disclosed air filter comprises a filter body thatdefines one or
more filter chambers, each of the filter chambers connected to a set of inlet and outlet; and one or more filter elements, each of the filter elements held within a corresponding filter chamber such that the air entering through the corresponding inlet passes through the corresponding filter element and gets filtered and finally exits through the corresponding outlet.
[025] In an aspect, the disclosed air filter assembly further comprises one or more pre-
filters, each of the pre-filters located between the filter element and the corresponding inlet;
wherein the pre-filters are characterized by not being in direct flow path of the air.
[026] In an aspect, each of the pre-filters are configured using a intake chamber housing
located within the filter chambers such that air entering through the corresponding inlet enters an internal cavity through a plurality of apertures located around circumference of the pre-filter housing. The plurality of apertures oriented such that the incoming air is directed to a perforated sheet positioned such that at least a part of the incoming impinges on the perforated sheet that is towards the inlet, such that at least a part of the impinging air along with contaminants present therein passes through the perforated sheet to the opposite side, and returns back towards the first side. The pre-filter further comprise a bigger size contaminant collection chamber located on the opposite side of the perforated sheet that such that the impinging air that enters through the perforated sheet undergoes turbulent motion before returning back towards the inlet side. The turbulent motion causes separation of the contaminants, and the separated contaminants are retained/deposited within the contaminant collection chamber.

[027] In an aspect, the intake chamber housing is held within the filter chamber by a cap
nut fitted on the open end of the filter chamber. In another aspect, the perforated sheet is held
sandwiched between butting ends of the intake chamber housing and the cap nut and the
contaminant collection chamber formed by a cavity in the cap nut.
[028] In an aspect, the air filter further comprises one or more drain plugs, each of the
vented drain plugs coupled to one of the contaminant collection chamber associated with the
pre-filters to enable periodic draining of contaminants collected in the contaminant collection
chamber
[029] In an aspect, the vented drain plugs are adapted to enable draining of the
contaminants by partial opening of the vented drain plug.
[030] In an aspect, the filter chambers are open from one end, wherein the open ends of
the filter chambers are used for accommodating the intake chamber housing and closed by a
cap nut of left hand thread and seal.
[031] In an aspect, the removable cap nut enables removal and replacement of the filter
elements for periodic cleaning and replacement.
[032] In an aspect, the vented drain plugs are fitted on the bottom cover adjacent the
corresponding contaminant collection chambers.
[033] Various objects, features, aspects and advantages of the inventive subject matter
will become more apparent from the following detailed description of preferred
embodiments, along with the accompanying drawing figures in which like numerals represent
like components
BRIEF DESCRIPTION OF THE DRAWINGS
[034] The accompanying drawings are included to provide a further understanding of
the present disclosure, and are incorporated in and constitute a part of this specification. The
drawings illustrate exemplary embodiments of the present disclosure and, together with the
description, serve to explain the principles of the present disclosure.
[035] FIGs. 1A, 1B and 1C illustrate exemplary front, side sectional viewsand the
exploded view of the proposed air filter assembly, in accordance with embodiments of the
present disclosure.
[036] FIG. 2 illustrates an exemplary sectional view of the proposed air filter assembly,
showing air flow path through the perforated sheet, in accordance with an embodiment of the
present disclosure.

[037] FIG. 3 illustrates an exemplary sectional view of the proposed air filter assembly,
showing trapped contaminants being discharged through the perforated sheet, in accordance with an embodiment of the present disclosure.
DETAILED DESCRIPTION
[038] The following is a detailed description of embodiments of the disclosure depicted
in the accompanying drawings. The embodiments are in such detail as to clearly
communicate the disclosure. However, the amount of detail offered is not intended to limit
the anticipated variations of embodiments; on the contrary, the intention is to cover all
modifications, equivalents, and alternatives falling within the spirit and scope of the present
disclosure as defined by the appended claims.
[039] Each of the appended claims defines a separate invention, which for infringement
purposes is recognized as including equivalents to the various elements or limitations
specified in the claims. Depending on the context, all references below to the "invention"
may in some cases refer to certain specific embodiments only. In other cases it will be
recognized that references to the "invention" will refer to subject matter recited in one or
more, but not necessarily all, of the claims.
[040] Various terms are used herein. To the extent a term used in a claim is not defined,
it should be given the broadest definition persons in the pertinent art have given that term as
reflected in printed publications and issued patents at the time of filing.
[041] Embodiments explained herein relate to an air filter assembly for filtering air in a
pneumatic brake system, the disclosed air filter assembly incorporating one or two filter
elements, each filter element catering to filtering need of a separate pneumatic circuit. Thus,
the proposed filter assembly does away with requirement of having separate filter assembly
for each pneumatic circuit in systems such as brake system of LHB coaches of Indian
Railways having two separate filters for filtering Brake Pipe Air and Feed Pipe Air. Likewise,
brake systems of other rail road transport vehicles that incorporate dual pipe systems that
have two independent pneumatic circuits and can be benefitted by the proposed air filter
assembly.
[042] It is to be appreciated that though the embodiments of the present disclosure have
been explained with reference to an air filter assembly having two filter elements for two
independent pneumatic circuits, the concept can be applied to have air filter assembly having
more than two filter elements catering to more than two independent pneumatic circuits, and

all such variations are well within the scope of the present application without any limitation
whatsoever.
[043] In an aspect, the disclosed air filter assembly incorporates a pre-filter for each
filter element, the pre-filter adapted to trap at least a part of contaminants before air passes
through the corresponding filter element. As can be appreciated, trapping part of
contaminants can help to improve life of the filter element between servicing, i.e. cleaning of
the filter element and/ or its replacement. In another aspect, integrating the pre-filter within
a single filter assembly does away with requirement of providing a separate pre-filter
assembly in each pneumatic circuit, reducing cost.
[044] It is to be appreciated that, though the embodiments of the present disclosure that
pertain to the pre-filter have been explained with reference to an air filter assembly having
two filter elements for two independent pneumatic circuits, the concept for pre-filter can also
be applied to an air filter assembly having just one pre-filter element catering to a single
pneumatic circuits, or to a filter assembly having more than two filter elements catering to
more than two independent pneumatic circuits, and all such variations are well within the
scope of the present application without any limitation whatsoever.
[045] In an aspect of the present disclosure, the disclosed pre-filter is not in direct flow
path of the air, and therefore, the pre-filtering arrangement does not require complete air to
pass through a filtering element. This is advantageous as a pre-filtering device in flow path
results in pressure drop.
[046] In an embodiment, the pre-filters incorporate a contaminant collection chamber
where trapped contaminants are stored, and can be periodically drained through a vented
drain plug. In another aspect, the vented drain plug does not require complete opening, and is
adapted to enable draining of contaminants by partial opening, thereby making the draining
process simple and quick for routine maintenance.
[047] In an embodiment, the proposed filter assembly incorporating two or more filter
elements for two or more independent pneumatic circuits, and corresponding pre-filters, is of
a construction that is simple, compact and cost effective to manufacture and maintain.
[048] Referring to FIGs. 1A, 1B and 1C where exemplary front, side sectional views
and exploded view of the proposed air filter assembly 100 are illustrated, as shown, the
disclosed air filter assembly 100 comprises a filter body 102 that incorporates two filter
chambers, such as 104-1 and 104-2 (collectively referred to as filter chambers 104). Filter
body 102 can be either a separate part or be a part of other elements such as manifold of
pneumatic brake circuit. Each of the two filter chamber 104 can be of cylindrical shape.

Bottom end of the filter chambers 104 can incorporate an opening, such as openings 130-1 and 130-2 (collectively 130). The opening 130 connects the filter chamber 104 to an intake chamber, such as intake chambers 118-1 and 118-2 (collectively 118). Intake chamber 118 in turn includes an intake port (also referred to as inlet), such as, referring to FIG. 1C, inlet 106-1 and 106-2 (collectively 106). Each of the filter chamber 104 incorporate delivery ports (also referred to as outlet), such as, referring to FIG. 1C, outlets 108-1 and 108-2 (collectively 108). Each filter chamber 104 holds a filter element, such as filter element 110-1 and 110-2 (collectively110) such that air enters through the corresponding inlet 106 passes through the corresponding filter element 110 and gets filtered and finally exits through the corresponding outlet 108.
[049] In an embodiment, the disclosed air filter assembly 100 further comprises two pre-
filters, each of the two pre-filters located between the filter element110 and the corresponding inlet 106. In an aspect, the pre-filters are characterized by not being in direct flow path of the air as would be described in below paragraphs.
[050] In an aspect, each of the one or more intake chambers is configured using one or
more intake chamber housings136-1 and 136-2 (collectively intake chamber housing 136) located below the filter element such that air entering through the corresponding inlet 106 enters an intake chamber 118 formed of an internal cavity in the intake chamber housing 136 through a plurality of apertures 128-1 and 128-2 respectively (collectively apertures 128) located around circumference of the intake chamber housing 136. The plurality of apertures 128 are oriented such that the incoming air is directed to a perforated sheet 112 positioned on lower side of the intake chambers 118 such that at least a part of the incoming air is directed to impinge on a side of the perforated sheet 112 that is towards the intake chamber 118, or inlet 106. Further, arrangement is such that at least a part of the impinging air along with contaminants present therein passes through the perforated sheet 112 to the opposite side, and returns back towards the first side.
[051] In an aspect, the intake chamber housing 136 is held within the filter chamber by a
cap nut 120 fitted on the open end of the filter chamber. In another aspect, the perforated sheet 112 is held sandwiched between butting ends of the intake chamber housing 136 and the cap nut 120as shown in the exemplary illustrations.
[052] In an embodiment, each of the pre-filter further comprises a contaminant
collection chamber, such as contaminant collection chamber 114-1 and 114-2 (collectively 114),located on the opposite side of the perforated sheet 112 such that the impinging air that enters through the perforated sheet 112 undergoes turbulent motion before returning back

towards the inlet side, i.e. to the intake chamber 118. The turbulent motion causes separation of the larger particle of contaminants, and the separated contaminants are retained/deposited within the contaminant collection chamber 114. In an embodiment, the contaminant collection chamber 114 is formed of a cavity in the cap nut 120 as shown in the exemplary illustrations.
[053] FIG. 2 illustrates an exemplary sectional view of the proposed air filter assembly
100, showing air flow path through the perforated sheet, in accordance with an embodiment
of the present disclosure. As shown, a part of air entering the intake chamber 118 directed to
impinge on the perforated plate 112, and enters the contaminant collection chamber 114
through the perforated sheet 112 located on opposite side of the perforated sheet 112.There it
undergoes turbulent motion, as shown by arrows, before returning back to the intake chamber
118. The turbulent motion causes separation of the contaminants, and the separated
contaminants are retained/deposited within the contaminant collection chamber 114.
[054] In an aspect, the air filter assembly 100 further comprises one or more vented
drain plugs, such as drain plugs 116-1 and 116-2 (collectively 116), each of the vented drain plugs 116 coupled to one of the contaminant collection chamber 114 associated with the pre-filters to enable periodic draining of contaminants collected in the contaminant collection chamber 114.
[055] In an aspect, the drain plugs 116 are adapted to enable draining of the
contaminants by partial opening of the vented drain plug 116. For this, the vented drain plug
116 can incorporate an inverted T shape drain hole, such as drain hole 126-1 and 126-2
(collectively 126). Vertical arm of the inverted T shape drain hole 126 opens in the
contaminant collection chamber 114, and two ends of the horizontal arm of the T shape drain
hole 126 are closed when the drain plug 116 is fully closed/ tightened. However, when the
vented drain plug 116 is opened, after partial opening itself, the two ends of the horizontal
arm of the T shape drain hole 126 get exposed, as shown in FIG. 3, providing a clear passage
from open end of the vertical arm of the inverted T shape drain hole 126 for the contaminants
to flow out from the contaminant collection chamber 114. When the draining is complete, the
drain plug 116 can be screwed in back to closed position to block the passage.
[056] FIG. 3 illustrates an exemplary sectional view of the proposed air filter assembly
100, showing trapped contaminants being discharged through the perforated sheet as explained above. As can be understood, air inside the air filter assembly 100, being under pressure, it flows out by itself when the vented drain plug 116 is opened, as shown by arrows

in FIG. 3. While moving out under pressure, it carries the contaminants, which are primarily condensate and contaminants, along with it.
[057] In an embodiment, the disclosed air filter assembly 100 is of simple construction
to enable ease of manufacture. For example, the cylindrical shaped filter chambers 104, contaminant collection chambers114 areof cylindrical shape open from bottom. Thus, the filter body 102 incorporating one or more of the two can be manufactured by any or a combination of a casting or machining processes. In particular, the filter body 102 can be made of Aluminium for light weight and ease of manufacturing and to dissipate heat and to allow the air to condensate.
[058] Further, open ends of the filter chambers 104 are closed by a separate cap nut 120-
1 and 120-2 (collectively 120).Suitable sealing elements such as 124-1 and 124-2 (collectively 124) can be provided to prevent leakage of air. Likewise, open ends of the contaminant collection chambers114 is closed by a separate cap nut 120 with appropriate sealing elements such as 122-1 and 122-2 (collectively 122).
[059] In an aspect, the removable cap nut 120 enables removal and replacement of the
filter elements 110 for periodic cleaning and replacement.
[060] In an aspect, the Vented drain plugs 116 are fitted on the cap nut120 the
corresponding contaminant collection chambers 114 with appropriate sealing elements such as 132-1 and 132-2 (collectively 132)..
[061] In an embodiment, the disclosed air filter assembly 100 can be mounted to any
panel having pneumatic circuit with appropriate sealing elements such as 134-1, 134-2, 134-3 and 134-4 (collectively 134) for Inlet and outlet ports.
[062] Thus, the present disclosure provides an air filter assembly that can cater to
filtering need of two or more independent pneumatic circuits, and incorporates pre-filter for each pneumatic circuit to trap contaminant before they reach the corresponding filter element thereby enhancing service life of the filter element. It also enables easy periodic maintenance with minimum and easy removal of parts.
[063] While the foregoing describes various embodiments of the invention, other and
further embodiments of the invention may be devised without departing from the basic scope thereof. The scope of the invention is determined by the claims that follow. The invention is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.

ADVANTAGES OF THE INVENTION
[064] The present disclosure provides an improved air filter with enhanced life of the
associated filter element between maintenance.
[065] The present disclosure provides an improved air filter that additionally pre-filter
the air to enhance life of the filter element between maintenance .
[066] The present disclosure provides an improved air filter that does not result in
significant increase in pressure drop due to pre-filtering.
[067] The present disclosure provides provide an improved air filter that that enables
easy removal/ discharge of contaminants trapped at pre-filtering stage just by partly loosening
the Vented drain plug thus by saving time of routine maintenance.
[068] The present disclosure provides an air filterthat separates the contaminants of
larger particle by channelizing the incoming air passage, thus by effectively improving the
maintenance periodicity of the filter element.
[069] The present disclosure provides an air filter assembly that incorporates air filter
for two or more independent air circuits of a pneumatic system.
[070] The present disclosure provides an improved air filter that is compact and cost
effective.
[071] The present disclosure provides an improved air filter that enables ease of periodic
maintenance by minimum and easy removal of parts.

We Claim:
1. An air filter assembly for filtering air in a pneumatic brake system for rail road
vehicles, the air filter comprising:
a filter body, the filter body defining one or more filter chambers, each of the one or more filter chambers connected to a set of inlet and outlet; and
one or more filter elements, each of the one or more filter elements held within a corresponding filter chamber out of the one or more filter chambers such that the air entering through the corresponding inlet passes through the corresponding filter element and gets filtered and finally exits through the corresponding outlet; wherein the air filter assembly further comprises one or more pre-filters, each of the one or more pre-filters located between one of the one or more filter elements and the corresponding inlet; wherein the one or more pre-filters are characterized by not being in direct flow path of the air.
2. The air filter assembly as claimed in claim 1, wherein each of the one or more pre-
filter comprises:
a perforated sheet positioned such that at least a part of the incoming air impinges on a first side of the perforated sheet such that the at least a part of the incoming air along with contaminants present therein passes through the perforated sheet to the opposite side, and returns back towards the first side;
a contaminant collection chamber located on a second side of the perforated sheet that is opposite the first side such that the at least a part of the incoming air that enters through the perforated sheet undergoes turbulent motion before returning back towards the first side to cause separation of the contaminants, and wherein the separated contaminants are retained within the contaminant collection chamber.
3. The air filter assembly as claimed inclaim 2, wherein the air filter further comprises one or more vented drain plugs, each of the one or more vented drain plugs coupled to one of the contaminant collection chamber associated with one of the one or more pre-filters to enable periodic draining of contaminants collected in the contaminant collection chamber
4. The air filter assembly as claimed in claim 3, wherein the one or more vented drain plugs are adapted to enable draining of the contaminants by partial opening of the vented drain plug.

5. The air filter assembly as claimed in claim 1, wherein the one or more filter chambers are open from one end, wherein the open ends of the each of the one or more filter chambers is closed by a separate cap nut .
6. The air filter assembly as claimed in claim 4, wherein the removal of the cap nut enables removal and replacement of the one or more filter elements for periodic cleaning and replacement.
7. The air filter assembly as claimed in claim 3 and 5, wherein the contaminant collection chambers are formed with in the cap nut.
8. The air filter assembly as claimed in claim 7, wherein the vented drain plugs are fitted on the corresponding cap nuts adjacent the corresponding contaminant collection chambers.
9. The air filter assembly as claimed in claim 1, wherein the air filter assembly is adapted for two independent pneumatic circuits.