U.S. patent number RE46,080 [Application Number 13/743,077] was granted by the patent office on 2016-07-26 for filtering apparatus and filter element.
This patent grant is currently assigned to HYDAC FILTERTECHNIK GMBH. The grantee listed for this patent is Hydac Filtertechnik GmbH. Invention is credited to Patrick Maurer, Norbert Sann.
United States Patent |
RE46,080 |
Maurer , et al. |
July 26, 2016 |
Filtering apparatus and filter element
Abstract
A filtering apparatus includes a pot-type filter housing (10), a
filter element (28) accommodated in the housing, a holding
mechanism (38) disposed in the filter housing (10) to removably fix
the filter element along its longitudinal axis, and a sealing
device (60) that seals between a lid (20) of the filter housing
(10) and the filter element (28). The holding mechanism (38) is
provided with cooperating holding elements embodied on the interior
face of the filter housing (10) as well as on the filter element
(28). The filtering apparatus dispenses with the need for O-seals
that are known in prior art and extend in a radial direction
between the filter element and the filter head as a housing lid
because the sealing device (60) encompasses at least one sealing
edge (62) or sealing surface placed parallel to the longitudinal
axis in a radial direction and seals under the effect of the
pressure applied it by the holding mechanism (38). The invention
further relates to a filter element that is to be used in such
filtering apparatus.
Inventors: |
Maurer; Patrick (Sulzbach,
DE), Sann; Norbert (Riegelsberg, DE) |
Applicant: |
Name |
City |
State |
Country |
Type |
Hydac Filtertechnik GmbH |
Sulzbach/Saar |
N/A |
DE |
|
|
Assignee: |
HYDAC FILTERTECHNIK GMBH
(Sulzbach/Saar, DE)
|
Family
ID: |
34961554 |
Appl.
No.: |
13/743,077 |
Filed: |
January 16, 2013 |
PCT
Filed: |
March 04, 2005 |
PCT No.: |
PCT/EP2005/002281 |
371(c)(1),(2),(4) Date: |
May 08, 2007 |
PCT
Pub. No.: |
WO2005/123216 |
PCT
Pub. Date: |
December 29, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
Reissue of: |
11629751 |
Mar 4, 2005 |
7997421 |
Aug 16, 2011 |
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Foreign Application Priority Data
|
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Jun 17, 2004 [DE] |
|
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10 2004 029 225 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B01D
35/30 (20130101); B01D 29/96 (20130101); B01D
29/114 (20130101); B01D 29/114 (20130101); B01D
29/96 (20130101); B01D 2201/305 (20130101); B01D
2201/302 (20130101); B01D 2201/4092 (20130101); B01D
2201/304 (20130101); B01D 2201/291 (20130101) |
Current International
Class: |
B01D
35/30 (20060101); B01D 27/07 (20060101); B01D
29/11 (20060101); B01D 29/96 (20060101) |
Field of
Search: |
;210/444,454,440,450,455 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2706017 |
|
Aug 1978 |
|
DE |
|
3805138 |
|
Aug 1989 |
|
DE |
|
199 04 981 |
|
Aug 2000 |
|
DE |
|
314963 |
|
May 1989 |
|
EP |
|
0 891 214 |
|
May 2001 |
|
EP |
|
589 457 |
|
Jun 1947 |
|
GB |
|
953 900 |
|
Apr 1964 |
|
GB |
|
WO2007/085247 |
|
Aug 2007 |
|
WO |
|
WO2007/085427 |
|
Aug 2007 |
|
WO |
|
Other References
Office Action, dated Apr. 15, 2014, for U.S. Appl. No. 13/743,077.
cited by examiner.
|
Primary Examiner: McKane; Elizabeth
Attorney, Agent or Firm: Wenderoth, Lind & Ponack,
L.L.P.
Claims
What is claimed is:
1. A filtering apparatus, comprising: a cup-shaped filter housing
with a housing cover; a filter element received inside said filter
housing and having an end cap on a longitudinal end thereof
adjacent said housing cover; a holder located in said filter
housing .[.detachable.]. .Iadd.detachably .Iaddend.securing said
filter element to said housing cover along a longitudinal axis
thereof and having holder elements interacting with one another and
formed on an inside of said housing cover and on said filter
element; and a seal providing a sealing effect between said housing
cover and said filter element, said seal having at least one
sealing surface facing in an axial direction parallel to said
longitudinal axis, said seal sealing under influence of pressure
applied thereto by said holder, and said seal .Iadd.and said holder
elements formed on said filter element all .Iaddend.being integral
with and formed of a same material .[.of.]. .Iadd.with
.Iaddend.said end cap .Iadd.as one piece.Iaddend..
2. A filtering apparatus according to claim 1 wherein said holder
comprises outer and inner threads on said filter element and said
housing cover, with said .[.holding.]. .Iadd.holder
.Iaddend.elements being turns of said outer and inner threads.
3. A filtering apparatus according to claim 2 wherein said seal is
located on said end cap concentrically to said outer thread
thereon; and said inner thread is in said housing cover.
4. A filtering apparatus according to claim 3 wherein said outer
thread encompasses a fluid passage in said filter element.
5. A filtering apparatus according to claim 3 wherein said filter
housing comprises several parts; and said inner thread encompasses
a fluid passage in said housing cover.
6. A filtering apparatus according to claim 5 wherein said seal
encompasses said holder at a transition point to said filter
element.
7. A filtering apparatus according to claim 2 wherein said threads
are rounded threads.
8. A filtering apparatus according to claim 1 wherein said filter
element comprises filter material extending along said longitudinal
axis, said end cap being directly coupled on one longitudinal end
of said filter material, said seal being on a side of said end cap
remote from said filter material.
9. A filter element for a filtering apparatus, comprising: filter
material extending along a longitudinal axis; an end cap mounted on
one longitudinal end of said filter material having a first
.Iadd.axial .Iaddend.side facing said filter material and an
opposite second .Iadd.axial .Iaddend.side facing away from said
filter material; .[.and.]. a seal on said second .Iadd.axial
.Iaddend.side being in a shape of a closed ring with a sealing
surface facing in an axial direction parallel to said longitudinal
axis, and being integral with and formed of a same material
.[.of.]. .Iadd.with .Iaddend.said end cap.Iadd.; and a connecting
branch extending in said axial direction on said second axial side
and integral with and formed of a same material with said end cap,
said seal, said connecting branch and said end cap being formed as
one piece.Iaddend..
10. A filter element according to claim .[.8.]. .Iadd.9
.Iaddend.wherein said end cap comprises an outer thread on said
.[.second side extending along a.]. connecting branch
.[.encompassing.]. .Iadd.and said connecting branch encompasses
.Iaddend.a fluid passage in said end cap.
11. A filter element according to claim .[.9.]. .Iadd.10
.Iaddend.wherein said seal encompasses said connecting branch.
12. A filter element according to claim .[.8.]. .Iadd.9
.Iaddend.wherein said end cap is directly coupled on said filter
material.
.Iadd.13. A filtering apparatus according to claim 1 further
comprising a catch groove formed in said filter housing and a catch
overlap formed in said housing cover. .Iaddend.
.Iadd.14. A filtering apparatus according to claim 1 wherein said
sealing surface engages a planar surface of said housing cover.
.Iaddend.
.Iadd.15. A filtering apparatus according to claim 3 wherein said
seal extends in said axial direction toward said housing cover,
above and to encompass at least a portion of said outer thread.
.Iaddend.
.Iadd.16. A filtering apparatus according to claim 4 wherein said
fluid passage comprises a funnel-shaped curvature. .Iaddend.
.Iadd.17. A filter element according to claim 9 wherein said
connecting branch has an outer thread and said seal extends in said
axial direction toward said outer thread, above and to encompass at
least a portion of said outer thread. .Iaddend.
.Iadd.18. A filter element according to claim 9 wherein said
connecting branch comprises a fluid passage having a funnel-shaped
curvature. .Iaddend.
.Iadd.19. A filter element according to claim 9 wherein said seal
omits rubber. .Iaddend.
Description
FIELD OF THE INVENTION
The present invention relates to a filtering apparatus having a
cup-like filter housing, a filter element held therein, and a
holding means located in the filter housing for detachable fixing
of the filter element along its longitudinal axis and having
holding elements which interact with one another and which are
formed on the inside of the filter housing and on the filter
element. A sealing means effects sealing between the housing cover
of the filter housing and the filter element. The present invention
furthermore relates to a filter element designed for the filter
device.
BACKGROUND OF THE INVENTION
Filter devices for holding filter elements are readily available
commercially in a host of embodiments. A not insignificant portion
of production costs in these filter devices is for making the
holding means for detachable fixing of the filter element within
the housing and for the sealing means for sealing the interior of
the filter element relative to the filter housing.
In the filter device described in EP 0891 214 B1, the holding means
has a spring configuration of two compression springs which act
against one another. By their resulting spring force, an end piece,
this is located on the filter element and which acts as a sealing
and holding element, is pushed onto a housing-side holding element.
The holding element forms a fluid connecting branch formed on the
head of the filter housing by a connecting piece which extends into
the support pipe of the filter element. The comparatively complex
design of the known holding means leads to high production costs.
Also, the known solution is less easy to install, in that the
filter element can slip unintentionally off the connecting branch
or can tilt at this location when put in place. This installation
difficulty leads to an adverse effect on the sealing action of the
sealing means. In the known solution, the sealing means has an
O-ring, preferably of rubber material, which is fixed in the radial
internal recess within the end cap of the filter element. In this
way, it radially effects sealing relative to the outer peripheral
side of the fluid connecting branch of the housing cover or of
filter head. This known sealing means with an O-ring is not suited
for all fluid media, for example, not for all hydraulic liquids,
poorly flammable liquids, corrosive media and for special
biodegradable liquids. Depending on the chemical structure of the
respective medium, a long-lasting sealing function cannot be
ensured.
DE-U-299 22 488 discloses a liquid filter which is easy to install,
with a cup-like filter housing, with a removable cover which closes
the filter housing, and with an interchangeable filter insert which
has its own filter surface. The filter insert is detachably
connected to the cover as the filter head of the housing.
Furthermore, the known solution has a support mandrel which extends
into the filter insert as a connecting branch of a holding means.
In the filter housing, connecting and holding means which are
referred to as an adapter is provided for the support mandrel,
which connecting and holding means are designed as holding elements
in the form of retaining fingers. In the known solution, the
support mandrel is detachably held in the filter insert. A first
installation module has the cover, the filter insert and the
support mandrel. A second installation module has the filter
housing and adapter with the retaining fingers. During installation
of the two installation modules, the adapter is securely connected
to the support mandrel. When the filter insert is replaced, the
support mandrel remains in the filter housing. In this respect,
installation problems (slippage, tilting) can also arise when the
filter element has to be pushed onto the support mandrel, for
example, when the filter is being replaced on site, with the
disadvantageous consequence that the sealing action of the sealing
means is adversely affected. The sealing means formed from an
O-ring in the radial direction effects support between the support
mandrel of the filter housing and the inner peripheral side of the
filter element. Although, in addition the support mandrel as a
component of the holding means in the longitudinal axial direction
parallel to the longitudinal axis of the filter element on its
lower base part in a receiving groove has another gasket which is
not subject to any further mechanical stress, in any case, as
described above the sealing action of the sealing means between the
filter element and support mandrel as a housing part is adversely
affected.
EP 1 287 871 A1 discloses another filter device with a cup-like
filter housing, a filter element therein and holding elements
detachably securing the filter element in the filter housing. The
holding elements in the known filter device are a receiver located
on the filter housing with an undercut forming at least one catch
surface. One end of the filter element, projecting, resilient
retaining fingers with catch projections form a detachable snap
connection by locking to the catch surface of the receiver. In this
way, installation and replacement of filter elements can be done by
simple locking and releasing of the snap connection. It is
sufficient to move the filter element axially in the filter housing
in the direction to the cup bottom until the snap connection snaps
in place. For dismounting from the cup-shaped housing, the filter
element can be simply pulled out. With the known solution, in terms
of a means of non-interchangeability, the result is that only
filter elements designed especially for the filter device can be
used for assuming a function. For example, no other components
which are formed optionally as aftermarket elements could endanger
the safe use of the filter device.
On the opposite end of the filter element with parts of the holding
means, the end cap of the filter element has a fluid connecting
branch which can be slipped onto a connecting branch part in the
housing cover or filter head. The sealing means is in turn an
O-ring which extends radially between the connection parts of the
cover part and filter element. In this respect the above described
disadvantages also apply to the known filter device according to
that European patent.
SUMMARY OF THE INVENTION
Objects of the present invention are to provide a filtering
apparatus and filter element therefor guaranteeing a reliable
connection of the filter element within the filter housing by the
holding means, having an especially simple, structural design
resulting in low production costs and easy installation, and having
good sealing action and resistance to corrosive media.
These objects are basically achieved by a filter device and a
filter element where the sealing means has at least one sealing
edge or sealing surface. The sealing edge or sealing surface is
located in the axial direction parallel to the longitudinal axis,
and seals under the influence of the pressure applied thereto by
the holding means. It is then possible to abandon conventional
O-rings which extend between the filter element and the filter head
as the housing cover in the radial direction. Nor does the sealing
means have to be made from rubber materials, as in the known
solutions, and is accordingly suitable for any type of fluid to be
filtered, even corrosive media. Depending on the medium to be
filtered in the form of a fluid, the sealing means can be
stipulated to be suitably resistant in terms of its material
selection. Damage to the sealing means in the various installation
processes can also for the most part be avoided, even if the filter
element were to be placed obliquely on parts of the holding means
so as to cause tilting. In this way, long lasting operation can be
ensured by the sealing means.
For use in a filter device on at least one end of the filter
element, an end cap is placed. On its side facing away from the
filter element, the end cap has a sealing means which, designed as
a closed ring with a sealing edge or sealing surface, is arranged
in the direction parallel to the longitudinal axis of the filter
element. The sealing means is located outside of the actual holding
means such that damage to the sealing means is avoided when the
filter element is fixed by the holding means within the filter
housing. By preference, the sealing means with its sealing edge is
an integral component of the filter element-end cap. For the end
cap configuration, and accordingly for the sealing means, a plastic
or steel material is resistant with respect to corrosive media can
be preferably selected. Fundamentally, it is also possible to
detachably integrate the sealing means into a receiving means, for
example, in the form of a receiving groove within the end cap. It
is essential that via a force means which can be formed from parts
of the holding means, pressing of the sealing means with its
sealing edge takes place in the axial direction between the
face-side end of the filter element and the housing cover or filter
head. In this connection, it is also possible to additionally or
alternatively arrange the sealing means on the filter head or
housing cover. The sealing means then works axially in the
direction of the face-side end of the filter element.
In one preferred embodiment of the filter device of the present
invention, the holding means has an outer thread and an inner
thread corresponding to it. The holding elements are formed from
the pertinent turns of the outer and inner threads so that it is
possible to connect the filter element to housing parts of the
filter housing to carry fluid by a screwing-on process which is
simple to carry out, or to detach them again from one another by an
unscrewing process. It is unimportant whether the outer thread is
assigned to the filter housing or the filter element. Based on the
thread characteristic of the holding means, the indicated solutions
involving pushing onto the connecting branch in the filter housing
can be abandoned to facilitate installation processes. In
particular, the filter element does not unintentionally slip off
the connecting branch, nor does it tilt on the connecting piece
configuration. This thread solution forms the force means making it
possible to brace the sealing means with its sealing edge or
sealing surface against parts of the filter housing, especially in
the form of a cover part (filter head) and/or against the end cap
of the filter element. The pressing of the sealing edge or sealing
surface of the sealing means is then determined essentially by its
resilience and flexibility.
With the present invention, only one specific type of filter
elements can ever be inserted into the filter housing. These filter
elements are specifically prepared accordingly for the indicated
threaded connection approach. Thus, the insertion of aftermarket
components can be avoided, as such replacement parts which, in
addition to their fundamentally poor quality, also as a result of
their less specific adaptation to the intended filter housing,
entail tightness problems on the fluid connecting points.
In one preferred embodiment of the filter device of the present
invention, the outer thread is located on the end cap of the filter
element and concentrically to it. Also, the inner thread is
integrated in the filter housing. Furthermore, the outer thread
comprises preferably a fluid passage site in the filter element,
and the filter housing is made in several parts. The inner thread
is held in the housing cover (filter head) of the filter housing,
and encompasses another fluid passage site. In this way, the filter
element can be inserted by a classical receiver in the filter
housing. By a snap-on or screw-on process of the cover on the
filter housing, the fluid-carrying connection from the hydraulic
circuit to the filter element is established by the thread and
threaded sections. Preferably, the connecting branch of the filter
element on the base side is encompassed by the sealing means.
Other objects, advantages and salient features of the present
invention will become apparent from the following detailed
description, which, taken in conjunction with the annexed drawings,
discloses a preferred embodiment of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
Referring to the drawings which form a part of this disclosure:
FIG. 1 is a schematic, not-to-scale, partial, perspective side view
of a filter device according to one embodiment of present
invention, with the cover part as the filter head screwed off;
FIG. 2 is a partial, perspective bottom view of the cover part of
the filter housing of FIG. 1; and
FIG. 3 is a partial, side elevational view of the top end of the
filter device with the filter element inserted and the cover part
in place on the otherwise cup-like filter housing of FIG. 1.
DETAILED DESCRIPTION OF THE INVENTION
A filter housing 10 is in the form or shape of a cup rotationally
symmetrical in its outline to the longitudinal axis 12, and has one
open top end 14 and a closed bottom (not shown). On the top end 14,
a peripheral catch groove 16 in the form of a snap connection can
be engaged by a catch overlap of the cover part or housing cover 20
of the filter housing 10, when the cover part 20 is placed on the
top end 14 of the filter housing 10 by a rotary or snap motion.
This snap and catch connection for the housing cover 20 with the
filter housing 10 is shown especially in FIG. 3. Alternatively, as
shown in FIG. 1, instead of a catch groove 16, a peripheral
elevation 22 can be provided with an external threaded segment (not
shown) to screw on the housing cover 20 by an internal threaded
segment (not shown). In both cases, as shown in FIG. 1, in the
direction of the top end 14, a projecting, peripheral sealing lug
24 at the top borders a sealing channel 26 which can house a
sealing means (not shown), for example, in the form of an O-ring or
the like. Optionally, sealing by the projecting sealing lug 24
without other sealing means is sufficient here.
The cup-like housing 10 is designed to hold a filter element 28 in
the form of a filter cartridge conventionally having a
circular-cylindrical inner support pipe with fluid passages
surrounded by the filter material 30. In this embodiment, the
filter element 28 should have a lower end assigned to the bottom of
the filter housing and closed by a plastic end cap which also forms
an enclosure for and directly engaging the facing end edge of the
filter material 30.
This end cap which is not detailed can be compression molded with
the support pipe in one piece from plastic. This lower end cap is
closed, that is, made fluid-tight, and need only to be inserted
within the filter housing 10 in the direction of its bottom, while
maintaining an axial distance. It would also be conceivable here to
use conventional holding and receiving means, as are known in the
prior art. On its end assigned to the upper end 14 of the filter
housing 10, the filter material 30 together with the support pipe
is lengthened by a preferably plastic, compression-molded head cap
or end cap 32 which likewise forms an edge enclosure 34 for and
directly engaging the bordering edge of the filter material 30 and
has a connecting branch 36. .Iadd.Accordingly, the end cap 32 is
integral with and formed of the same material as the connecting
branch 36. .Iaddend.
This connecting branch 36 is part of the holding means or holder 38
having an outer thread 40 along the connecting branch 36.
Corresponding thereto in the housing cover 20, set back opposite
its free edge 42, an inner thread 44 is aligned in the direction of
the longitudinal axis 12 of the filter device. The actual holding
or holder elements 46 of the holding means 38 include of the
pertinent thread turns of the outer thread 40 and inner thread
44.
As FIG. 1 and FIG. 3 furthermore show, the outer thread 40 on the
end cap 32, also referred to as the element cover, is arranged
concentrically to it. The inner thread 44 is integrated in the
bottom or inner part of the housing cover 20. The connecting branch
36 and accordingly the outer thread 40 concentrically encompass a
fluid passage site 48 in the filter element 28. The inner thread 44
integrated in the housing cover 20 borders another fluid passage
site 50. The inner threaded segment can be a component of an insert
sleeve 52 (compare FIG. 2) inserted into a hole therefor in the
housing cover 20, and can also be formed of a plastic material in
the form of a compression or clamping sleeve. In addition to the
other fluid passage site 50, the cover part 20 has a fluid inlet
site 54 for the fouled fluid.
Inflowing, fouled fluid, especially hydraulic medium, travels with
the housing cover 20 in place on the filter housing 10 via the
fluid inlet site 54 into the interior of the filter housing 10 and
then flows through the filter element 28 from outside to inside.
The dirt to be removed remains in the filter material 30 of the
filter element 28. The cleaned fluid has then collected within the
support pipe leaves the filter housing 10 with the housing cover 20
via the fluid passage site 48 and the other fluid passage site 50.
For its filter function, the filter device can be connected to a
hydraulic circuit (not shown) via connecting points 56.
For an economical sealing means, it has been found to be
advantageous to make the thread turns of the outer thread 40 and
the mating inner thread 44 as so-called round threads. Furthermore,
to ensure a stiff configuration, the connecting branch 36 is kept
as small in diameter and in overall height. In particular, in
diameter, it is kept several times smaller than the outside
diameter of the end caps 32. To provide favorable flow conditions,
moreover the free end of the connecting branch 36 is provided on
the inner peripheral side with a funnel-shaped curvature 58.
Furthermore, the connecting branch 36 on its base-side transition
point to the end cap 32 is surrounded with a concentrically
extending sealing means or seal 60. As FIG. 3 shows in particular,
the sealing means 60 is made triangular in cross section and seals
with a sealing edge 62 tapering in the direction of the bottom of
the housing cover 20 if it is placed on the filter housing 10
(compare FIG. 3).
This sealing edge 62 can be slightly compressed if, when the
housing cover 20 is fixed, it is drawn by the holding elements 46
in the form of thread turns in the direction of the filter element
28 and of the filter housing 10. The holding means 38 therefore
yields a positive and nonpositive fluid connection between the
filter element 28 and the housing cover 20. The sealing means 60 is
nonpositively compressed in contact with the housing cover 20.
.Iadd.As best shown in FIG. 3, the sealing edge 62 engages a planar
surface of the housing cover 20. .Iaddend.Because the sealing means
60 with the sealing edge 62 is located on the end cap 32 with the
threaded connecting branch 36, sealing is effected between the
filter element 28 and the filter head in the form of the housing
cover 20. Thus, other sensitive seal materials, for example, of
rubber, which are intended to ensure the sealing function in the
manner of an O-ring, are omitted. Since the sealing means 60 is
made of the same material as the end cap 32 and is especially an
integral component of it, .[.the.]. .Iadd.as is the connecting
branch 36, the sealing means 60 and the connecting branch 36 are
formed with the end cap 32 as one piece. The .Iaddend.sealing means
60 is thus suited for all hydraulic liquids, poorly flammable
liquids, corrosive media and for all biodegradable liquids. Media
for conventional sealing means, especially of rubber material, can
no longer guarantee a sealing function over a long interval.
Since the filter element 28 is held in a defined manner by the
threaded segment in the housing cover 20 and accordingly in the
filter head, in mounting and dismounting processes, for example, to
replace a used filter element 28 by a new one, it cannot, as in the
prior art, lead to the connecting branch 36 slipping off
unintentionally. Rather a precisely manageable contact situation
prevails. When the housing cover 20 is locked on the filter housing
10, it is ensured that a fluid-carrying connection is also produced
within the filter device. Preferably, the filter element is first
screwed into the cover part for an insertion process and then it is
locked to the filter housing 10. Moreover, for the filter device of
the present invention, a defined filter element 28 is necessary in
terms of the connection construction, so that it is not possible to
insert alternative aftermarket components into the existing filter
device housing which could otherwise endanger the operation of the
filter device as a result of tightness problems.
The sealing means 60 is selected in terms of its overall height
such that on the base-side outlet of the threaded segment of the
outer thread 40 it projects as a round threaded by half a thread
turn. Instead of a rounded thread, another metric thread can be
used. Furthermore, several gaskets--also in another geometrical
configuration--in a concentric arrangement and optionally at a
different sealing height can encompass the connecting branch 36.
Furthermore, it is still within the scope of the present invention
to interchange the arrangement of the outer and inner threads so
that then the housing 20 has the outer thread and the end cap 32 of
the filter element 28 has the inner thread 44 (design not shown).
In addition to the described force means in the form of threaded
segments of the holding means, it is also possible to brace
nonpositively, for example, by a spring element in the form of a
compression spring, comparably to the solution as shown in FIG. 5
of EP 0 891 214 B1, against the connecting branch in the filter
head or cover part of the filter housing and to apply a sealing
force to the sealing means in the axial direction.
While one embodiment has been chosen to illustrate the invention,
it will be understood by those skilled in the art that various
changes and modifications can be made therein without departing
from the scope of the invention as defined in the appended
claims.
* * * * *