WO2008116519A1

WO2008116519A1 - Filter device

Info

Publication number: WO2008116519A1
Application number: PCT/EP2008/000519
Authority: WO
Inventors: Michael Sakraschinsky; Stefan Hennes; Peng Wang
Original assignee: Hydac Filtertechnik Gmbh
Priority date: 2007-03-28
Filing date: 2008-01-24
Publication date: 2008-10-02
Also published as: DE102007014813A1; EP2125147A1

Abstract

A filter device with a filter housing (1) having a fluid inlet (11) and a fluid outlet (13), and with a filter element (5) which can be received in the housing (1) and which can be exchanged. The filter element (5) has a first filter medium (27) which surrounds a first filter cavity (51) extending along a longitudinal axis. Fluid to be cleaned can flow from the outer side of the filter medium (27) to the first filter cavity (51). The filter element (5) also has a second filter medium (33) which surrounds a second filter cavity (53) which is coaxial to and lies inside the first filter cavity (51), wherein the second filter cavity (53) can make a fluid connection to the fluid outlet (13) of the filter housing (1). The invention is characterized in that a flow guide unit (57) is provided which forms two separate flow paths for the fluid to be cleaned, the first of which brings the fluid which has passed through the first filter medium (27) directly to the fluid outlet (13) of the filter housing (1), and the second of which connects the fluid inlet (11) of the filter housing to the outer side of the second filter medium (33).

Description

Hydac Filtertechnik GmbH, industrial area, 66280 Sulzbach / Saar

filter means

The invention relates to a filter device having a filter housing having a fluid inlet and a fluid outlet and having a filter element which can be accommodated therein and exchanged, which has a first filter medium which surrounds a first filter cavity extending along a longitudinal axis and from its outside to the first filter cavity can be traversed by the fluid to be cleaned, and a second filter medium, which surrounds a coaxial to the first filter cavity, further inner second cavity which can be brought into fluid communication with the fluid outlet of the filter housing.

Filter devices of this type are known in a variety of embodiments and sizes. For example, WO 02/062447 A1 shows a device of this type in which a hollow-cylindrical filter element is arranged inside the filter housing, to the outside of which dirty fluid is supplied via a fluid inlet of the filter housing, which flows through the external filter medium from outside to inside. The thus filtered liquid is then removed via the fluid outlet in the filter housing for further use. The longer the filter element for the filtration is in operation, the more it is added by soiling, until Finally, the filter element forms a nearly impermeable barrier to the fluid flow. In order to avoid malfunctions due to the resulting increase in the pressure difference between the fluid inlet and the fluid outlet, it is state of the art to provide a bypass valve as a so-called bypass device, which opens at a pressure difference exceeding a threshold value and a fluid-conducting path bypassing the filter medium added by soiling towards the fluid outlet releases.

In the above known solution, a corresponding bypass valve with a spring-loaded closing body is provided within the first filter cavity and arranged such that, when the bypass valve is open, uncleaned fluid enters the first filter cavity located inside the first filter medium. In the latter, coaxial to the first filter medium is a second filter medium, which in turn surrounds an inner second cavity from which the fluid can flow off via the fluid outlet of the filter housing. During normal operation of the known filter device, ie when the bypass valve is closed, the fluid to be cleaned first flows through the first filter medium from the outside to the inside in the first filter cavity, where it passes to the outside of the second filter medium and after flowing through the second medium to the inner second filter cavity and from this to the fluid outlet. When opening the bypass valve due to a clogging of the first filter medium, the unpurified fluid enters the first filter cavity directly via the bypass valve, flows through the second filter medium from outside to inside and exits from the fluid outlet of the filter housing.

The operating behavior of the known solution is unsatisfactory insofar as the series connection of the first and second filter medium, as they Given in normal operation when the bypass valve is closed, where the filter media are respectively flowed through successively, leads to a low filtration efficiency, because the fluid to the second filter medium already comes in a state of the first filter medium largely purified. Since the second filter medium has to be designed as a bypass protection screen in the case of actuation of the bypass valve, it is not very suitable to perform a fine filtration of the fluid already cleaned by the first filter medium.

In view of this problem, the invention has the object to provide a filter device available, which in contrast is characterized by an improved performance.

According to the invention this object is achieved by a filter device having the features of claim 1 in its entirety.

According to this, an essential feature of the invention resides in the fact that a flow-guiding device is provided as an integrated component which prescribes two flow paths through which the first and second filter medium are connected in parallel in terms of flow for the fluid to be cleaned entering the filter housing, which means that two filter media, which are arranged coaxially to one another within the other, each of the outer side can be flowed through simultaneously with unpurified fluid, which leads to an optimal utilization of the available space in the filter housing, so that for the same time flowed through the filter media Can realize filter area increase over known solutions of 50% or more. In this case, the arrangement may be such that the flow guiding device has a separating tube, which extends coaxially with the filter media at a distance from both the inner wall of the first filter medium and from the outside of the second filter medium in the longitudinal direction and the first filter cavity of the Outside of the second filter medium separated, wherein the separation tube has an open end for the entry of fluid in the along the inside of the separation tube extending second flow path and the second flow path terminating closed end. Such embodiments are characterized by a particularly simple and space-saving construction of the flow guide.

The inner, second cavity may have at the end, which is connectable to the located at the bottom of the filter housing fluid outlet, a bottom-side annular body having a skirt for the second

Forming filter medium and the closure of the closed end of the separation tube, which is connected to the annular body on the outer circumference, which is located at a radial distance from the enclosure of the second filter medium.

In embodiments in which a bypass valve is provided, by the actuation of which a fluid connection between the fluid inlet and the second filter cavity comes about, the arrangement is preferably such that adjoins the end remote from the annular body of the second filter cavity a thereto coaxial third filter cavity, which is separated from the second filter cavity by the bypass valve and surrounded by a third filter medium coaxial with the second filter medium, the outside, aligned with the outside of the second filter medium, along the second flow path at a distance of the inside of the separation tube extends. In a particularly advantageous manner, in this case, the third filter medium can be designed specifically as a bypass protection filter, since it is only flowed through in the case of actuation of the bypass valve, wherein the fluid which enters from the second flow path through the third filter medium (bypass protection filter) into the third filter cavity over the bypass valve and the second filter cavity flows directly over the fluid outlet.

The second filter medium preferably surrounds an inner, fluid-permeable support tube which is seated at one end in the surround of the bottom-side annular body and at the other end sits together with the second filter medium in an enclosure which is formed in a first housing part of the bypass valve. Preferably, the arrangement is in this case made such that the bypass valve has an axially adjacent to the first housing part second housing part, which forms an enclosure for the third filter medium and the inner support tube. Advantageously, forms in this construction, the bypass valve with its housing parts not only the normally locked, actuated by pressure release separator between the second and third filter cavity, but also forms the mechanical connection element with enclosures for both filter media concerned with associated support tubes.

In this case, the second housing part can form a valve seat for a valve body guided on the first housing part and prestressed into the closed position by spring force.

Since the third filter medium is flowed through by fluid only when the bypass valve is open, it can be designed in an advantageous manner as specially adapted to the particular circumstances by-pass filter. In particularly advantageous embodiments, the filter element has a second bottom-side annular body, via the annular opening of the first filter cavity with the fluid outlet of the filter housing is connectable and the peripheral region forms a border for the bottom end of the first filter medium and the inner support tube.

At the end opposite the bottom ring bodies, the filter element may comprise a cover member closing the third filter cavity, leaving a fluid passage open into the open end of the separation tube and forming bezels for first and third filter media and for their support tubes.

Preferably, the separation tube forms at its open, adjacent to the fluid passage of the cover part end an inlet extension, on the end edge of the separation pipe is fixed to the inside of the support tube of the first filter medium.

According to claim 13, the subject of the invention is also a filter element provided for use in the filter device according to the invention, which is exchangeably receivable in a filter housing of the filter device.

The invention with reference to an embodiment shown in the drawing will be explained in detail. Show it:

1 shows a schematic simplified drawn longitudinal section of the embodiment of the filter device; 1 is a larger-scale, cut-away and perspective view of only the lower end of the filter element of the exemplary embodiment adjoining the annular body, and FIG. 3 shows a perspective oblique view of the one exchangeable unit drawn on the smaller scale filter element.

The filter device has a filter housing 1, shown only in FIG. 1, with a housing cover 3 which can be removed in order to be able to insert and replace a filter element in the largely hollow-cylindrical interior of the filter housing 1. The designated as a whole in Fig. 5 with filter element has the widely used in such filter elements circular cylindrical cartridge shape, wherein an integrally formed from a plastic material upper cover part 7 a hinged

Hanger 9 has as a handle for the insertion and replacement of the filter element 5.

The filter housing 1 has a lateral fluid inlet 11 for the fluid to be cleaned and a fluid outlet 13 forming a central opening for the outlet of the purified fluid at the housing bottom. The opening edge of the fluid outlet 13 forms a housing 15 projecting into the interior of the housing, the peripheral edge forms an element receptacle for the filter element 5, more precisely a seat for the annular opening 17 (FIG. 2) of a bottom annular body 19, which forms the lower end of the filter element 5.

As can be seen most clearly from FIG. 2, the annular body 19 forms between its elevated outer peripheral edge 21 and a second ter inner, likewise superscript ring surface 23 a skirt 25 for the end portions of a first filter medium 27, which rests with its inside on a fluid-permeable support tube 29. The filter medium 27 is a filter mat which forms a type of hollow cylinder and which is pleated in the usual way and not shown in detail and is secured together with the end of the support tube 29 via corresponding adhesive and / or sealing means in the enclosure 25. In a corresponding manner, the cover member 7 forms at its the filter medium 27 cross-peripheral edge 31 a skirt for the upper ends of the filter medium 27 and the support tube 29, which also via bonding and / or sealing compound is formed a solid bond with the cover part 7, made of plastic is integrally molded.

Coaxially to the first filter medium 27 and to its support tube 29, a second filter medium 33 with inner support tube 35 and a third filter medium 37 with inner support tube 39 are provided radially further inwardly. As for the upper ends of the first filter medium 27 and its support tube 29, the cover part 7 radially further inside also forms a skirt 41 for the upper ends of the third filter medium 37 and the support tube 39, wherein the anchorage on the cover part 7 is also formed by gluing. At the other, lower end of the third filter medium 37 and its support tube 39 is in alignment and also coaxial with the first filter medium 27, the second filter medium 33 with its support tube 35, wherein the junction between the second filter medium 33 and the third filter medium 37 by a first housing part 43rd and a second housing part 45 is formed, which together form a bypass valve, which will be discussed below. The second filter medium 33 extending from the bypass valve downwards with a support tube 35 whose length is approximately twice as long as the length of the third filter element 37 and its Support tube 39 are bordered at their lower end to another, ring-side annular body 47. Its design and positional relationship to the other annular body 19, which forms the bottom end of the filter element 5, are most clearly shown in FIG. 2 can be removed. As shown, this annular body 47 located further up is located at an axial distance from the end-side annular body 19, so that between the outer side of the annular body 47 and the annular opening 17, a fluid passage 49 is formed, via which on the inside of the first filter medium 27 Filter cavity, here referred to as the first filter cavity 51, with the fluid outlet 13 of the filter housing 1 is in communication. Via the annular opening 50 of the annular body 47 and the filter cavity located on the inside of the second filter medium 33, here referred to as the second filter cavity 53, with the fluid outlet 13 of the filter housing 1 in fluid connection.

The second filter medium 33 extends approximately over 2/3 of the length of the first filter medium 27 to the first housing part 43 of the bypass valve. This housing part 43, together with the second housing part 45 of the bypass valve adjacent thereto and connected to it, forms fusions both for the second filter medium 33 and its support tube 35 and for the third filter medium 37 with its support tube 39 second filter cavity 53 separate third filter cavity 55 is closed at the end facing away from the bypass valve end of the cover part 7.

To form the bypass valve, a valve body 46 is axially displaceable on the first housing part 43, which is biased by a spring 44 in its closed position in which the valve body 46 bears sealingly against a valve seat 48 formed on the second housing part 45. The by the spring 44th caused closing force is selected so that at a predetermined pressure difference between the third filter cavity 55 and the second filter cavity 53 communicating with the fluid outlet 13 opens the bypass valve.

The first filter cavity 51 connected to the fluid outlet 13 via the passage 49 forms part of the first of the two flow paths which are predetermined in the filter device for the flow of fluid through the fluid. The flow guiding device prescribing the flow paths has a separating tube 57 as main component. This extends from his to the

Cover part 7 subsequent open end 59 coaxial at a distance from the support tube 29 and at an approximately equal distance from the outside of the third filter medium 37 and the second filter medium 33 to the annular body 47 at the end of the second filter cavity 53 out. At this end, the separation pipe 57 is attached to the outer circumference of the annular body 47 and thereby completed. At the upper, open end 59, the separating tube 57 has an extension 61 which forms an inlet funnel, via which uncleaned fluid, from the interior of the housing cover 3, enters the interior of the separating tube 57 via inflow slots 63 in the cover part 7, d. H. to the second flow path, which extends coaxially to the along the outside of the separation tube 57 extending part of the first flow path. The open end 59 of the separation tube 57 is fixed to the opening edge of the extension 61 by stitching to the support tube 29 at this.

In normal filtration operation, ie with a closed bypass valve, the fluid flow is in the manner shown in Fig. 1 with the unnumbered, drawn with solid line flow arrows. In the event that the bypass valve opens, results in a fluid flow in the manner as illustrated in Fig. 1 with not quantified, drawn with dashed line flow arrows. Accordingly, the fluid passes in normal operation from the outside of the filter element 5 after flowing through the first filter medium 27 via the first flow path along the outside of the separation tube 57 via the passage 49 to the fluid outlet 13. At the same time the fluid to be cleaned reaches the extension 61 at the open end 59 of the separation tube, ie it passes in the course of the second flow path to the outside of the second filter medium 33, flows through this from outside to inside and also reaches the fluid outlet 13 as purified fluid via the annular opening 50 of the annular body 47. Thus results for the first filter medium 27 and second Filter medium 33 a parallel filtration operation. Due to the coaxial arrangement of the filter media and the resulting optimal use of space, a particularly large filter surface is available. Upon response of the by-pass valve, the third filter cavity 55 surrounded by the third filter medium 37 is in direct fluid communication with the fluid outlet 13 while the outside of the third filter medium 37 surrounding the third filter cavity is adjacent to the unpurified fluid in the second flow path. The third filter medium 37 flows through only when the bypass valve is open, ie it merely has the function of a bypass valve.

Protective filter and can be specially designed for this task. By the separator a homogeneous, turbulence-free flow path for the fluid to be filtered is achieved.

Claims

Patent claims

1. Filter device comprising a filter housing (1) having a fluid inlet (1 1) and a fluid outlet (13) and having a filter element (5) which can be accommodated and exchanged therein and which is a first filter medium

(27), which surrounds a first filter cavity (51) extending along a longitudinal axis and from which the outside of the first filter cavity (51) can be flowed through by the fluid to be cleaned, and a second filter medium (33), the one to the first Filter cavity (51) coaxial, further inlying second filter cavity (53) which is in fluid communication with the fluid outlet (13) of the filter housing (1), characterized in that a flow guide (57) is provided, which is for the fluid to be cleaned forms two separate flow paths, via which the first passed through the first filter medium (27) fluid passes directly to the fluid outlet (13) of the filter housing (1) and whose second flow path the fluid inlet (11) of the filter housing with the outside of the second Filter medium (33) connects.

2. Filter device according to claim 1, characterized in that the Strömungsleiteinrichtung a separating tube (57), which is to the filter media (27, 33) coaxially at a distance from both the inside of the first filter medium (27) and from the outside of the second filter medium (33) extends longitudinally and separates the first filter cavity (51) from the outside of the second filter medium (33), the separator tube (57) having an open end (59) for entry of fluid into the inside of the separator tube (57) extending second flow path and the second flow path terminating closed end (40).

3. Filter device according to claim 2, characterized in that the inner, second filter cavity (53) at the end which is connectable with the at the bottom of the filter housing (1) located fluid outlet (13) bar, a bottom annular body (47) forming a skirt (38) for the second filter medium (33) and the closure of the closed end (40) of the separator tube (57) connected to the annular body (47) at its outer circumference, which is at a radial distance from the enclosure (38) of the second filter medium (33) is located.

4. Filter device according to one of claims 1 to 3, characterized in that a by a preselected pressure difference between the fluid inlet (1 1) and fluid outlet (13) of the filter housing (1) operable Bypass valve is present, which when actuated a fluid connection between the Fluid inlet (1 1) and the second filter cavity (53) produces.

5. Filter device according to claim 4, characterized in that at the bottom of the (47) distal end of the second filter cavity (53) a thereto coaxial third filter cavity (55) connects, separated from the second filter cavity (53) through the bypass valve and of a third filter medium (37) coaxial with the second filter medium (33) is surrounded, whose outside, aligned with the outside of the second filter medium (33), extends along the second

Flow path iinerhalb the separation tube (57) extends.

6. Filter device according to claim 5, characterized in that the second filter medium (33) has an inner, fluid-permeable support tube (35). which sits at one end in the enclosure (38) of the bottom ring body (47) and sits at the other end together with the second filter medium (33) in a skirt formed in a first housing part (43) of the bypass valve.

7. Filter device according to claim 6, characterized in that the bypass valve has an axially to the first housing part (43) adjoining the second housing part (45) which forms an enclosure for the third filter medium (37) and its inner support tube (39).

8. Filter device according to claim 7, characterized in that the second housing part (45) forms a valve seat (48) for a on the first housing part (43) guided by spring force (44) biased in the closed position valve body (46).

9. Filter device according to claim 8, characterized in that the third filter medium (37) forms a bypass valve actuated by fluid flow through the protective filter.

10. Filter device according to claim 9, characterized in that the filter element (5) has a second bottom annular body (19), via the annular opening (1 7) of the first filter cavity (51) and the second filter cavity (53) with the fluid outlet (1 3) of the filter housing (1) are connectable and the peripheral region of a skirt (25) for the bottom end of the first filter medium (27) and its inner

Support tube (29) forms.

1 1. Filter device according to claim 10, characterized in that the filter element (5) on which the bottom-side annular bodies (19, 47) entge a lid portion (7) which closes the third filter cavity (55), a fluid passage (63) in the open end (59) of the separation tube (57) and enclosures (31, 41) for the first (27) and third filter medium (37) and for the support tubes (29, 39) forms.

12. Filter device according to claim 1 1, characterized in that the separating tube (57) at its open, to the fluid passage (63) of the cover part (7) adjacent the end of an inlet extension (61), over the end edge of the separating tube (57) the inside of the Stützroh- res (29) of the first filter medium (27) is attached.

13. Filter element (5) for a filter device according to one of claims 1 to 12, with a flow guide (57) which forms two separate flow paths for the fluid to be cleaned.