Title of Invention	FILTER ELEMENT
Abstract	The invention relates to a filter element for filtering fluids, which is received in a filter housing and which is configured as a filter candle-type element extending along a longitudinal axis. An inner fluid space of said element is surrounded by a filter material that separates the inner fluid space from an outer fluid space within the filter housing. The body of the filter element, at least in a portion of its length based on its longitudinal axis, has a cross-section in the shape of an orbiform curve (1) deviating from the circular form.

Title of Invention

FILTER ELEMENT

Abstract

The invention relates to a filter element for filtering fluids, which is received in a filter housing and which is configured as a filter candle-type element extending along a longitudinal axis. An inner fluid space of said element is surrounded by a filter material that separates the inner fluid space from an outer fluid space within the filter housing. The body of the filter element, at least in a portion of its length based on its longitudinal axis, has a cross-section in the shape of an orbiform curve (1) deviating from the circular form.

Full Text	Hydac Filtertechnik GmbH, Industriegebiet, 66280 Sulzbach/Saar Filter Element The invention relates to a filter element which can be accommodated in a filter housing for filtering of fluids and which is designed as a filter cartridge which extends along a longitudinal axis in the form of a body in which an inner fluid space is surrounded by filter material which separates the inner fluid space from the outer fluid space within the filter housing. Filter elements of this type are common. In conjunction with fluid systems of the most varied type, these filter elements are widely used to filter process liquids, pressurized liquids, such as hydraulic oils, liquid fuels and lubricants, for treatment of liquid media and the like. In many cases, in fluid systems in which filter elements are used, only a limited useful space is available for installation or attachment of system parts which contain the pertinent filter elements in the form of filter cartridges. On the other hand, to be able to filter the correspondingly large volumetric flows, a sufficient size of the filter area made available by the filter element or filter elements is necessary. With respect to these requirements, the object of the invention is to devise a filter element which enables optimization of the ratio of the filtering surface to the required installation space so that system components which are intended for filtering of the pertinent fluids can be made especially space-saving. As claimed in the invention, this object is achieved by a filter element which has the features of claim 1 in its entirety. While the filter elements of the prior art are circular, cylindrical or cuboidal, the filter element as claimed in the invention is characterized according to the characterizing part of claim 1 in that it has a special outline in the form of an orbiform curve which deviates from the circular shape on at least part of its length. As is known, the circumference of a circle is equal to the periphery of the corresponding orbiform curve which deviates from the circular shape. Accordingly, in a filter element in which the periphery of the element of the filter cartridge determines the size of the filtering surface, this filtering surface for a cross section in the shape of an orbiform curve is exactly as large as for a cross section in the shape of a circle with the same diameter. The shape of the orbiform curve deviating from the circle shape however makes it possible to house in a given installation space a larger filtering surface than would be possible in a filter element of circular- cylindrical shape. This non-circular shape of the orbiform curve makes it possible to integrate the filter element in a space-saving manner matched to the given boundaries of the installation space such that in a given installation space a larger periphery of the filter element and thus a larger filtering surface are available than would be possible in the installation of a cylindrical filter element at the same installation site. Preferably the filter element as claimed in the invention has the shape of an orbiform curve in a cross section which is perpendicular to the longitudinal axis. The cross-sectional shape corresponding to the orbiform curve can optionally be provided in only the longitudinal sections of the body of the filter element which are critical or important to housing the filter element or can extend preferably over the entire length of the body of the filter element. The cross-sectional shape can be a Reuleaux polygon, for example an orbiform curve, which is formed from an equilateral triangle with circular segments which replace its straight legs. The subject matter of the invention is also a filter device which is designed to hold at least one filter element, in particular a filter element as claimed in the invention, and which has the features of claim 7. In that accordingly the outline of the filter housing has a special shape which is selected to match the non-circular cross-sectional shape of at least one filter element which can be held in the housing, it becomes possible to optimize the filter housing, with consideration of both a special cross-sectional shape of the filter element or the filter elements, and also with respect to a given geometry of the available installation space, in the shape of its outline such that space-saving installation of a filtering surface as large as possible is achieved. The outline of the filter housing can have the shape of an orbiform curve which deviates from the round shape. An especially favorable ratio between the size of the filtering surface and the housing volume can be achieved for example when the filter element to be held in the housing has a matching cross-sectional orbiform shape. In embodiments in which the outline of the filter housing is round and the filter housing has the shape of a circular cylinder, a good filtering surface/housing volume ratio can be implemented when several filter elements are held in the housing and each have a cross section in the shape of an orbiform curve which deviates from the round shape. Of the filter elements as claimed in the invention which are made in this way, four orbiform filter elements as claimed in the invention can be accommodated in a circular-cylindrical filter housing which is dimensioned for holding three conventional filter elements which are circular in outline. Since the periphery of the circular-cylindrical, conventional filter element and of the corresponding orbiform filter element as claimed in the invention is the same in each case, that is, each of the three known filter elements makes available the same filtering surface as each of the four filter elements as claimed in the invention, thus the total filtering surface when using the orbiform filter elements as claimed in the invention is one third larger than when using known filter elements. The invention will be detailed below using one embodiment shown in the drawings. FIG. 1 shows the geometry of a Reuleaux orbiform curve based on an equilateral triangle and FIG. 2 shows a highly schematically simplified representation in illustration of the installation situation of filter elements with a circular cross section and of filter elements with a cross section in the shape of an orbiform curve in a circular- cylindrical filter housing. FIG. 1 shows details of a Reuleaux orbiform curve with an outline designated as 1. The orbiform curve is based on an equilateral triangle 3 with corners 5, 7, and 9, each corner being the center of a circle with radius r1 and an arc with radius r2. These two radii are shown in the figure only proceeding from the corner 5. The magnitude of the radius r2 is in a ratio to the radius r1 such that the corresponding arc tangentially adjoins the circle with a radius r1 and thus the closed outline designated as 1 in FIG. 1 results. The diameter d1 of the orbiform curve formed in this way corresponds to the sum of the radii r1 and r2. The periphery of the orbiform curve, i.e., the length of the outline 1, has the same dimension as the circumference of a circle with diameter d1. In FIG. 2, in which the wall of the filter housing which has a round base surface 13 is designated as 11, the installation position of three filter elements 15 with a circular cross section is shown. At the same time, the installation position of four orbiform filter elements 17 is shown, with a cross-sectional shape which corresponds to the Reuleaux orbiform curve shown in FIG. 1. In this connection, as shown in FIG. 2, the circular diameter of the filter element 15 is equal to the diameter of the orbiform curve of the filter element 17. As is to be seen, in the filter housing 11 which is dimensioned for three round filter elements 15, four orbiform filter elements 17 can be accommodated. As is also to be seen from FIG. 2, the orbiform filter elements 17 are each installed in the filter housing 11 in a positional alignment such that they are immediately adjacent to wall 11 of the filter housing with the central region 19 of their outer side which is arched in the shape of an arc with a larger radius of curvature. Claims 1. Filter element (17) which can be accommodated in a filter housing (11) for filtering of fluids and which is designed as a filter cartridge which extends along a longitudinal axis in the form of a body in which an inner fluid space is surrounded by filter material which separates the inner fluid space from the outer fluid space within the filter housing, characterized in that the body of the filter element (17) has a cross section in the shape of a orbiform curve (1) which deviates from the circular shape on at least one part of its length relative to the longitudinal axis. 2. The filter element as claimed in claim 1, wherein it has the shape of an orbiform curve (1) in a cross section perpendicular to the longitudinal axis. 3. The filter element as claimed in claim 1 or 2, wherein the cross section has the shape of an orbiform curve (1) in preferred longitudinal sections of the body of the filter element. 4. The filter element as claimed in claim 1 or 2, wherein the cross section of the body of the filter element has the shape of an orbiform curve (1) over its entire length. 5. The filter element as claimed in one of claims 1 to 4, wherein the cross section of the body of the filter element has the shape of a Reuleaux polygon (1). 6. The filter element as claimed in claim 5, wherein the cross-sectional shape is an orbiform curve (1) which is formed from an equilateral triangle with circular segments which replace its straight legs. 7. Filter device for holding at least one filter element, especially one (17) as claimed in one of claims 1 to 6, with a filter housing (11) in the shape of a hollow body with an outline which defines the size of the interior which is available for accommodating at least one filter element (17), wherein the outline of the filter housing (11) has a shape which is selected to match the non-circular cross-sectional shape of at least one filter element (17). 8. The filter device as claimed in claim 7, wherein the outline of the filter housing (11) has the shape of a non-circular orbiform curve. 9. The filter device as claimed in claim 7, wherein the outline of the filter housing (11) is circular and the filter housing (11) has the shape of a circular cylinder. 10. Filter device as claimed in claim 9 for holding filter elements (17) as claimed in claim 6, wherein there are four filter elements (17) next to one another in the interior of the filter housing (11). 11. The filter device as claimed in claim 10, wherein the central area (19) of the outer side of the filter elements (17) which is arched in an arc shape with the larger radius of curvature of an orbiform curve (1) is nearest the inside wall of the circular-cylindrical filter housing (11). ABSTRACT The invention relates to a filter element for filtering fluids, which is received in a filter housing and which is configured as a filter candle-type element extending along a longitudinal axis. An inner fluid space of said element is surrounded by a filter material that separates the inner fluid space from an outer fluid space within the filter housing. The body of the filter element, at least in a portion of its length based on its longitudinal axis, has a cross-section in the shape of an orbiform curve (1) deviating from the circular form.

Full Text

Hydac Filtertechnik GmbH, Industriegebiet, 66280 Sulzbach/Saar
Filter Element
The invention relates to a filter element which can be accommodated in a filter housing for
filtering of fluids and which is designed as a filter cartridge which extends along a longitudinal axis
in the form of a body in which an inner fluid space is surrounded by filter material which separates
the inner fluid space from the outer fluid space within the filter housing.
Filter elements of this type are common. In conjunction with fluid systems of the most
varied type, these filter elements are widely used to filter process liquids, pressurized liquids, such
as hydraulic oils, liquid fuels and lubricants, for treatment of liquid media and the like. In many
cases, in fluid systems in which filter elements are used, only a limited useful space is available for
installation or attachment of system parts which contain the pertinent filter elements in the form of
filter cartridges. On the other hand, to be able to filter the correspondingly large volumetric flows, a
sufficient size of the filter area made available by the filter element or filter elements is necessary.
With respect to these requirements, the object of the invention is to devise a filter element
which enables optimization of the ratio of the filtering surface to the required installation space so
that system components which are intended for filtering of the pertinent fluids can be made
especially space-saving.

As claimed in the invention, this object is achieved by a filter element which has the features
of claim 1 in its entirety.
While the filter elements of the prior art are circular, cylindrical or cuboidal, the filter
element as claimed in the invention is characterized according to the characterizing part of claim 1
in that it has a special outline in the form of an orbiform curve which deviates from the circular
shape on at least part of its length. As is known, the circumference of a circle is equal to the
periphery of the corresponding orbiform curve which deviates from the circular shape. Accordingly,
in a filter element in which the periphery of the element of the filter cartridge determines the size of
the filtering surface, this filtering surface for a cross section in the shape of an orbiform curve is
exactly as large as for a cross section in the shape of a circle with the same diameter. The shape of
the orbiform curve deviating from the circle shape however makes it possible to house in a given
installation space a larger filtering surface than would be possible in a filter element of circular-
cylindrical shape. This non-circular shape of the orbiform curve makes it possible to integrate the
filter element in a space-saving manner matched to the given boundaries of the installation space
such that in a given installation space a larger periphery of the filter element and thus a larger
filtering surface are available than would be possible in the installation of a cylindrical filter element
at the same installation site.
Preferably the filter element as claimed in the invention has the shape of an orbiform curve
in a cross section which is perpendicular to the longitudinal axis.
The cross-sectional shape corresponding to the orbiform curve can optionally be provided in
only the longitudinal sections of the body of the filter element which are critical or important to
housing the filter element or can extend preferably over the entire length of the body of the filter
element.

The cross-sectional shape can be a Reuleaux polygon, for example an orbiform curve, which
is formed from an equilateral triangle with circular segments which replace its straight legs.
The subject matter of the invention is also a filter device which is designed to hold at least
one filter element, in particular a filter element as claimed in the invention, and which has the
features of claim 7.
In that accordingly the outline of the filter housing has a special shape which is selected to
match the non-circular cross-sectional shape of at least one filter element which can be held in the
housing, it becomes possible to optimize the filter housing, with consideration of both a special
cross-sectional shape of the filter element or the filter elements, and also with respect to a given
geometry of the available installation space, in the shape of its outline such that space-saving
installation of a filtering surface as large as possible is achieved.
The outline of the filter housing can have the shape of an orbiform curve which deviates
from the round shape. An especially favorable ratio between the size of the filtering surface and the
housing volume can be achieved for example when the filter element to be held in the housing has a
matching cross-sectional orbiform shape.
In embodiments in which the outline of the filter housing is round and the filter housing has
the shape of a circular cylinder, a good filtering surface/housing volume ratio can be implemented
when several filter elements are held in the housing and each have a cross section in the shape of an
orbiform curve which deviates from the round shape.
Of the filter elements as claimed in the invention which are made in this way, four orbiform
filter elements as claimed in the invention can be accommodated in a circular-cylindrical filter
housing which is dimensioned for holding three conventional filter elements which are circular in
outline. Since the periphery of the circular-cylindrical, conventional filter element and of the

corresponding orbiform filter element as claimed in the invention is the same in each case, that is,
each of the three known filter elements makes available the same filtering surface as each of the
four filter elements as claimed in the invention, thus the total filtering surface when using the
orbiform filter elements as claimed in the invention is one third larger than when using known filter
elements.
The invention will be detailed below using one embodiment shown in the drawings.
FIG. 1 shows the geometry of a Reuleaux orbiform curve based on an equilateral triangle
and
FIG. 2 shows a highly schematically simplified representation in illustration of the
installation situation of filter elements with a circular cross section and of filter
elements with a cross section in the shape of an orbiform curve in a circular-
cylindrical filter housing.
FIG. 1 shows details of a Reuleaux orbiform curve with an outline designated as 1. The
orbiform curve is based on an equilateral triangle 3 with corners 5, 7, and 9, each corner being the
center of a circle with radius r1 and an arc with radius r2. These two radii are shown in the figure
only proceeding from the corner 5. The magnitude of the radius r2 is in a ratio to the radius r1 such
that the corresponding arc tangentially adjoins the circle with a radius r1 and thus the closed outline
designated as 1 in FIG. 1 results.
The diameter d1 of the orbiform curve formed in this way corresponds to the sum of the radii
r1 and r2. The periphery of the orbiform curve, i.e., the length of the outline 1, has the same
dimension as the circumference of a circle with diameter d1.

In FIG. 2, in which the wall of the filter housing which has a round base surface 13 is
designated as 11, the installation position of three filter elements 15 with a circular cross section is
shown. At the same time, the installation position of four orbiform filter elements 17 is shown, with
a cross-sectional shape which corresponds to the Reuleaux orbiform curve shown in FIG. 1. In this
connection, as shown in FIG. 2, the circular diameter of the filter element 15 is equal to the diameter
of the orbiform curve of the filter element 17. As is to be seen, in the filter housing 11 which is
dimensioned for three round filter elements 15, four orbiform filter elements 17 can be
accommodated.
As is also to be seen from FIG. 2, the orbiform filter elements 17 are each installed in the
filter housing 11 in a positional alignment such that they are immediately adjacent to wall 11 of the
filter housing with the central region 19 of their outer side which is arched in the shape of an arc
with a larger radius of curvature.

Claims
1. Filter element (17) which can be accommodated in a filter housing (11) for filtering of fluids
and which is designed as a filter cartridge which extends along a longitudinal axis in the
form of a body in which an inner fluid space is surrounded by filter material which separates
the inner fluid space from the outer fluid space within the filter housing, characterized in
that the body of the filter element (17) has a cross section in the shape of a orbiform curve
(1) which deviates from the circular shape on at least one part of its length relative to the
longitudinal axis.
2. The filter element as claimed in claim 1, wherein it has the shape of an orbiform curve (1) in
a cross section perpendicular to the longitudinal axis.
3. The filter element as claimed in claim 1 or 2, wherein the cross section has the shape of an
orbiform curve (1) in preferred longitudinal sections of the body of the filter element.
4. The filter element as claimed in claim 1 or 2, wherein the cross section of the body of the
filter element has the shape of an orbiform curve (1) over its entire length.
5. The filter element as claimed in one of claims 1 to 4, wherein the cross section of the body
of the filter element has the shape of a Reuleaux polygon (1).
6. The filter element as claimed in claim 5, wherein the cross-sectional shape is an orbiform
curve (1) which is formed from an equilateral triangle with circular segments which replace
its straight legs.

7. Filter device for holding at least one filter element, especially one (17) as claimed in one of
claims 1 to 6, with a filter housing (11) in the shape of a hollow body with an outline which
defines the size of the interior which is available for accommodating at least one filter
element (17), wherein the outline of the filter housing (11) has a shape which is selected to
match the non-circular cross-sectional shape of at least one filter element (17).
8. The filter device as claimed in claim 7, wherein the outline of the filter housing (11) has the
shape of a non-circular orbiform curve.
9. The filter device as claimed in claim 7, wherein the outline of the filter housing (11) is
circular and the filter housing (11) has the shape of a circular cylinder.
10. Filter device as claimed in claim 9 for holding filter elements (17) as claimed in claim 6,
wherein there are four filter elements (17) next to one another in the interior of the filter
housing (11).
11. The filter device as claimed in claim 10, wherein the central area (19) of the outer side of the
filter elements (17) which is arched in an arc shape with the larger radius of curvature of an
orbiform curve (1) is nearest the inside wall of the circular-cylindrical filter housing (11).

ABSTRACT

The invention relates to a filter element for filtering fluids, which is received in a filter
housing and which is configured as a filter candle-type element extending along a
longitudinal axis. An inner fluid space of said element is surrounded by a filter material
that separates the inner fluid space from an outer fluid space within the filter housing.
The body of the filter element, at least in a portion of its length based on its
longitudinal axis, has a cross-section in the shape of an orbiform curve (1) deviating
from the circular form.

Documents:

03516-kolnp-2006 abstract.pdf

03516-kolnp-2006 claims.pdf

03516-kolnp-2006 correspondence others.pdf

03516-kolnp-2006 description(complete).pdf

03516-kolnp-2006 drawings.pdf

03516-kolnp-2006 form-1.pdf

03516-kolnp-2006 form-2.pdf

03516-kolnp-2006 form-3.pdf

03516-kolnp-2006 form-5.pdf

03516-kolnp-2006 international publication.pdf

03516-kolnp-2006 international search atuthority report.pdf

03516-kolnp-2006 pct others.pdf

03516-kolnp-2006 priority dpcument.pdf

03516-kolnp-2006-correspondence others-1.1.pdf

03516-kolnp-2006-correspondence-1.2.pdf

03516-kolnp-2006-correspondence-1.3.pdf

03516-kolnp-2006-form-26.pdf

03516-kolnp-2006-international search authority report-1.1.pdf

3516-KOLNP-2006-(27-05-2014)-ABSTRACT.pdf

3516-KOLNP-2006-(27-05-2014)-ANNEXURE TO FORM 3.pdf

3516-KOLNP-2006-(27-05-2014)-CLAIMS.pdf

3516-KOLNP-2006-(27-05-2014)-CORRESPONDENCE.pdf

3516-KOLNP-2006-(27-05-2014)-DESCRIPTION (COMPLETE).pdf

3516-KOLNP-2006-(27-05-2014)-DRAWINGS.pdf

3516-KOLNP-2006-(27-05-2014)-FORM-1.pdf

3516-KOLNP-2006-(27-05-2014)-FORM-2.pdf

3516-KOLNP-2006-(27-05-2014)-FORM-5.pdf

3516-KOLNP-2006-(27-05-2014)-OTHERS.pdf

3516-KOLNP-2006-(27-05-2014)-PETITION UNDER RULE 137.pdf

3516-KOLNP-2006-(28-05-2008)-FORM 13.pdf

3516-KOLNP-2006-CORRESPONDENCE 1.3.pdf

3516-KOLNP-2006-CORRESPONDENCE.pdf

3516-KOLNP-2006-FORM 13.pdf

3516-KOLNP-2006-FORM 18-1.1.pdf

3516-kolnp-2006-form 18.pdf

3516-KOLNP-2006-FORM 26.pdf

3516-KOLNP-2006-GRANTED-ABSTRACT.pdf

3516-KOLNP-2006-GRANTED-CLAIMS.pdf

3516-KOLNP-2006-GRANTED-DESCRIPTION (COMPLETE).pdf

3516-KOLNP-2006-GRANTED-DRAWINGS.pdf

3516-KOLNP-2006-GRANTED-FORM 1.pdf

3516-KOLNP-2006-GRANTED-FORM 2.pdf

3516-KOLNP-2006-GRANTED-FORM 3.pdf

3516-KOLNP-2006-GRANTED-FORM 5.pdf

3516-KOLNP-2006-GRANTED-SPECIFICATION-COMPLETE.pdf

3516-KOLNP-2006-INTERNATIONAL SEARCH REPORT & OTHERS.pdf

3516-KOLNP-2006-REPLY TO EXAMINATION REPORT.pdf

3516-KOLNP-2006-TRANSLATED COPY OF PRIORITY DOCUMENT.pdf

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Patent Number

262873

Indian Patent Application Number

3516/KOLNP/2006

PG Journal Number

39/2014

Publication Date

26-Sep-2014

Grant Date

22-Sep-2014

Date of Filing

24-Nov-2006

Name of Patentee

HYDAC FILTERTECHNIK GMBH

Applicant Address

INDUSTRIEGEBIET 66280 SULZBACH/SAAR

Inventors:

#	Inventor's Name	Inventor's Address
1	MERTENS,HELMUT	AM HESSELBORN 27 66292 RIEGELSBERG
2	SCHUNK,ANDRESS	KASTANIENWEG 2, 66914 WALDMOHR

PCT International Classification Number

B01D 29/11

PCT International Application Number

PCT/EP2005/005216

PCT International Filing date

2005-05-13

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	10 2004 028 862.2	2004-06-02	Germany