WO2015180815A1

WO2015180815A1 - Filter device

Info

Publication number: WO2015180815A1
Application number: PCT/EP2015/000885
Authority: WO
Inventors: Alexander WOHLERS; Viktor Josef Lauer; Philipp Hilzendegen; Norbert Sann
Original assignee: Hydac Filtertechnik Gmbh
Priority date: 2014-05-24
Filing date: 2015-04-30
Publication date: 2015-12-03
Also published as: EP3148670A1; DE102014007848A1

Abstract

A filter device having at least one filter element (3) accommodated in a filter housing (19, 21, 61) which has at least two attachment points (A, B) serving alternately to supply non-filtrate and to remove filtrate, wherein by means of a reversal device (15) the fluid stream, which changes direction by way of the attachment points (A, B), passes through the filter element (3) in only one predefinable direction, characterized in that the reversal device has at least one valve slide mechanism (15) of which the valve piston (17), guided in a valve housing (27; 63) and controlled by the respective stream of non-filtrate in the assigned attachment point (A, B), frees the passage of the fluid stream from the unclean side (23; 77) of the filter element (3) to the attachment point (A, B) that is attached to the clean side (F) of the filter element (3).

Description

Hydac Filtertechnik GmbH, industrial area, 66280 Sulzbach / Saar

filter means

The invention relates to a filter device with at least one filter element, which is accommodated in a filter housing which has at least two connection points, which serve alternately the supply of unfiltrate and the removal of filtrate, wherein by means of a reversing device of the respective connection points In the direction reversing fluid flow passes through the filter element in only one predeterminable direction.

In some hydraulic circuits, where filtering devices are used for operating fluids, such as hydraulic oil, the flow direction of the fluid flow in the piping system may change, depending on the respective operating conditions. Since the filter elements used for the filtration of the fluids in question may only be operated in one direction of flow due to the design, it is apt to dispense with filtration in circuits with reversing flow directions. However, in view of the high demands which such systems have to make on the purity of the fluids in order to avoid damage or failure of the hydraulic components of the system, the absence of filtration is only rarely acceptable. With regard to this, it is state of the art (line filter D1 MH010-01 of the RT filter technology, published in the Internet under RT-F ilter.de/2001-09- 04); to provide for the fluid flow passing to the filter element, a reversing device adapted to the flow direction. In this case, a flow rectification by means of a kind of Graetz circuit, which is made up of four seat valves. Since in such circuits a larger number of components is required, namely four valve body, four valve seats and four valve springs, resulting in a disadvantageous high demand for space and correspondingly high production costs. In addition, relatively high pressure losses occur, which can be several bar for larger volume flows.

Based on this prior art, the invention has the object to provide a filter device of the type mentioned is available, which is characterized by a simple, compact and inexpensive to produce.

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

Characterized in that, according to the characterizing part of claim 1, the reversing device comprises a valve slide device, the valve piston is driven by the respective Unfiltratstrom, which is present at one or the other connection point, provides the operating pressure itself, from one connection point or from the other Connection point forth, the control pressure for switching the valve slide device in the switching position, in which the unfiltered stream passes to the raw side of the filter element. When using only one valve and its automatic control, the invention is characterized by low construction costs and a compact design with low production costs. With only one valve located in the fluid flow pressure losses are also minimized.

In the case of a valve piston which is pressure-actuated directly from the unfiltrate, the control of the connection points from unfiltrate feed to filtrate removal and vice versa is essentially instantaneous or simultaneous. In particular, the Switching movements of the valve piston almost instantaneously, when the valve piston is mounted freely movable in the valve housing. Alternatively, however, it is also possible to provide spring centering for the valve piston in a central position, in which the opening cross sections are closed both towards the raw side and towards the clean side of the filter element. This ensures that when changing the flow direction in the pipe system there is no danger that the filter element is briefly flowed through in the wrong direction. With regard to the valve construction, the arrangement can advantageously be made so that the valve piston is fluid-conducting connected at its opposite end faces, each having a connection point at which alternately the Unfiltratstrom with a predetermined pressure, ie the operating pressure of the device is present.

Furthermore, starting from its two free end faces, the valve piston can each have a hollow chamber which, separated from one another by a wall part, has at least one passage opening which connect depending on the displacement position of the valve piston passages in the valve housing with the respective hollow chamber or lock them. In this construction, the valve piston itself, with its separate hollow chambers, forms the fluid guide between the outer connection points and those passage points of the valve housing which, depending on the switching position of the valve piston, lead to the raw side or the clean side of the filter element.

The valve housing may be part of the filter housing or flanged as a separate block. In a particularly advantageous embodiment, the valve housing is an integral part of a Filterkop- fes, to the formation of the filter housing, a filter pot with the filter element can be connected, wherein the passage points in the valve housing are formed from annular channels, one of which is connected to the raw side of the filter element and depending on the displacement position of the valve piston, the other on the clean side. Here, a middle annular channel of a group of three ring channels in two tangentially merging connecting channels, which are connected to the raw side of the filter element pass over, receive a collecting channel to the clean side of the filter element between them, which merges into two branch lines, one of which in an annular channel and from which the other flows into the other ring channel. In this design of the channels, low flow losses occur during operation.

In a particularly advantageous manner, the valve slide device can be integrated with its valve housing in the filter element which, with its preferably pleated filter mat, comprises the valve housing at a predeterminable distance. In comparison to designs with flanged on the valve housing valve block or with built-in filter head valve housing a particularly space-saving design can be realized. With such a design, the filter device can also be designed as a low-cost filter without the possibility of an element change, as well as a serviceable version with removable filter element. Due to the compact design, the filter device can also be integrated as an in-line filter in hose lines of the relevant system. In particular, in embodiments with integrated in the filter element valve slide arrangement, the arrangement is advantageously made so that the filter element received in the filter housing to the outside limits the raw side and the inside with the clean side. With particular advantage, the valve housing may have two pairs of grouped passageways, with the two being furthest from each other spaced passages alternately supply the raw side of the filter element with unfiltered material and serve to these adjacent passage points of each pair depending on the Verfahrstellung the valve piston, alternately connected to the clean side of the filter element, the removal of the filtrate.

The invention with reference to embodiments shown in the drawings will be explained in detail. Show it:

Fig. 1 a and 1 b in symbol representation a Graetz circuit for the

Flow rectification of a filter element flowing through a fluid flow according to the prior art;

Fig. 2 is a symbol representation of the hydraulic circuit of a

Changeover device for flow rectification in a filter device according to an embodiment of the invention;

Fig. 3 is a drawn with a housing interruption

Longitudinal section of an embodiment of the device according to the invention with a reversing device according to FIG. 2;

Fig. 4 is a longitudinal section of the embodiment according to the section line IV - IV of Fig. 3 and a longitudinally cut drawn perspective view of a second embodiment of the filter device according to the invention.

1 shows a device according to the prior art constructed in the manner of a Graetz circuit for rectifying a fluid flow flowing through a filter element 3. In the subfigure 1a, an operating state is shown in which at the junction A of the circuit unfiltered material flows under an operating pressure and at a junction B of the circuit filtrate flows after the fluid has passed through the filter element 3 in the direction indicated by flow arrow 5 direction. According to a Graetz circuit arrangement, the device has four seat valves, which can each be flowed through in only one flow direction and are each formed by spring-loaded check valves. Of these, there is a first check valve 7 between the connection point A and the non-filtrate input U of the filter element 3. A second check valve 9 is arranged between the second connection point B and the non-filtrate input U of the filter element 3. The check valves 7 and 9 are each oriented such that the fluid path is released from the connection point A to Unfiltrateingang U pending at port A unfiltrate via the check valve 7 or that at pending at the junction B Unfiltratdruck the connection via the check valve 9 to the unfiltered input U is released.

Between the filtrate outlet F of the filter element 3 and the connection points A and B are a third check valve 1 1 and a fourth check valve 13, each blocking the connection to the unfiltrate pressure leading junction A or B, but the connection between see filtrate outlet F and release the connection point A or B, at which no unfiltrate pressure is present.

In the operating state of FIG. 1 b, where the unfiltrate pressure is present at the connection parts B, the check valve 9 opens to the unfiltrate inlet U of the filter element 3, while the check valve 7 closes, as does the check valve 1 3. The filtrate outlet F of the filter element 3 effluent filtrate passes through the opening check valve 1 1 now to junction A.

2 shows the circuit of the reversing device for an embodiment of the filter device according to the invention. Instead of the Graetz circuit with four check valves a valve slide device in the form of a hydraulically operated 4/2-way valve 15 is provided, the valve piston 1 7 on the left side in Fig. 2 located end face with the fluid pressure of the junction A and on the opposite end face with the Fluid pressure of the junction B is acted as control pressure. Fig. 2 shows the switching position of the valve piston 1 7 prevailing at the junction B unfiltrate, wherein the connection is made from the junction B to the unfiltered input U of the filter element 3 and the filtrate output F is connected to the connection point A. In the reverse flow direction with prevailing at the junction A unfiltrate pressure, the valve piston moves 1 7 in Fig. 2 to the right, so that the junction A with the unfiltered inlet U is in communication and the filtrate F is connected to the junction B.

3 and 4 show a practical embodiment in which the valve slide device 15 is part of a filter head 19 which forms a filter housing together with a detachably attachable to him filter pot 21, in which the filter element 3 can be accommodated. This can be flowed through in the filtration operation from outside to inside, so that the Room 23 between the outside of the filter element 3 and the inside of the filter cup 21, the raw side and thus the unfiltered input U forms. The filter element 3 has in the usual manner with filter cartridges on a hollow cylindrical filter mat surrounding a concentric to the filter longitudinal axis 25, inner filter cavity, which forms the clean side, wherein the filtrate F is coaxial with the connection to the filter head 19.

In this extends at right angles to the filter longitudinal axis 25 extending from the junction A to junction B passage, which forms the valve housing 27 with a travel axis 29 for the axial movement of the valve piston 17. Starting from its two end faces 31 and 32 facing the connection points A and B, the latter has in each case a hollow chamber 35 and 37 which are separated from one another by a wall 39 located in the center of the valve piston 17. In the vicinity of this wall 39, each hollow chamber 35 and 37 has a ring of passage openings 41 and 43, respectively. Depending on the switching position of the valve slide device 15, that is, depending on the axial position of the valve piston 17, the passage openings 41 and 43 are aligned on passageways formed in the valve housing 27 by annular channels 45, 47 and 49 which surround the valve axis 29 concentrically and arranged in a group of three are, wherein the central annular channel 47 is aligned with the longitudinal axis 25. This middle annular channel 47 is, as shown in FIG. 4 can be removed via two connecting channels 51 and 53, the tangenti- ally open into the annular channel 47 and extend parallel to the longitudinal axis 25 with the unfiltrateingang U, ie with the space 23 of the crude side connected in the filter housing. The outer annular channels 45 and 49 are connected via an obliquely extending connecting line 55 and 57 with the filtrate output F in combination. In the operating state shown in FIGS. 3 and 4, in which, in accordance with the state shown in Fig. 2, the unfiltered pressure is present at the junction B, the valve piston 1 7 is in the left-side switching position, wherein the through holes 43rd are aligned with the central annular channel 47 so that unfiltered material passes from the annular channel 47 via the connecting channels 51 and 53 (FIG. 4) to the chamber 23 of the crude side. The other passage openings 41 are aligned with the left side annular channel 45, so that the filtrate output F via the connecting line 55, the through holes 41 and the hollow chamber 35 with the connection point A is in communication. At the same time, the annular channel 49 is closed by the valve piston 1 7, so that the connection between the junction B and the unfiltered output F is blocked. In the reversed flow direction, wherein the unfiltrate pressure of the connection point A shifts the valve piston 17 to the right, the through-openings 41 are in alignment with the central annular channel 47, so that now the unfiltered material via the connection channels 51, 53 (FIG. 4) to the space 23 passes, while the passage openings 43 are aligned with the annular channel 49, so that the filtrate flows from the filtrate output F via the connecting line 57 to the connection point B.

FIG. 5 shows an exemplary embodiment in which the valve slide device 15 is installed in the filter housing 61. More specifically, the valve housing 63 is disposed concentrically within the clean-side forming filter cavity 65. The valve piston 1 7 corresponds to the example described above, thus has hollow chambers 35 and 37 emanating from the end faces, which are separated by a wall 39 adjacent to which the through openings 41 and 43 are located. Unlike the example described above, two pairs of ports are formed in the wall of the valve housing 63, each pair being located near an end of the valve housing 63, each pair having a rim of Passages has. These are denoted by 69 and 71 in the upper pair in FIG. 5 and 73 and 75 in the lower pair.

FIG. 5 shows the operating state in which the unfiltrate pressure is present at the connection point A, so that the valve piston 1 7 is moved downwards in the FIGURE. As can be seen, the valve piston 1 7 releases the passage points 69 in this position, so that the unfiltered material reaches the dirty side 77 on the outside of the filter element 3. At the same time, the through-openings 43 of the valve piston 1 7 are aligned with the passage points 73 of the lower pair so that filtrate enters the hollow chamber 37 via the through-openings 43 and flows out via the connection point B from the room forming the clean side. In the reverse flow direction and upwardly displaced valve piston 1 7, the passage points 75 of the lower pair are released, so that unfiltered material from the junction B to the raw side 77 passes. At the same time, the passage openings 41 are aligned with the passage points 71 of the lower ring of the upper pair, so that the filtrate flows out of the space 65 of the clean side via the hollow chamber 35 to the connection point A. While the embodiment of Fig. 5 is closed on both sides

Filter housing 61, one of the housing end portions 81 or 83 may be formed as a lid which is removable to allow replacement of the filter element 3 by this is withdrawn together with its end caps 85 and 87 from the green body forming a valve housing 63.

Claims

P a t e n t a n s r ü c h e

Filter device with at least one filter element (3) which is accommodated in a filter housing (19, 21, 61) which has at least two connection points (A, B) which alternately serve to supply unfiltrate and to remove filtrate, wherein by means of a reversing device (1 5) the fluid flow, which reverses in direction via the connection points (A, B), traverses the filter element (3) in only one predeterminable direction, characterized in that the reversing device has at least one valve slide device (1 5 ), whose valve piston (17), guided in a valve housing (27; 63), is controlled by the respective unfiltrate flow in the assignable connection point (A, B) via the raw side (23; 77) of the filter element (3), the fluid flow to that connection point (A. B) releases the clean side (F) of the filter element

(3) is connected.

Filter device according to claim 1, characterized in that the reversal of the connection points (A, B) from unfiltrate supply to filtrate removal and vice versa takes place essentially promptly or at the same time.

Filter device according to claim 1 or 2, characterized in that the valve device (1 5) has at least one valve piston (1 7) which is connected in a fluid-carrying manner on its opposite end faces (31, 33) to one connection point (A, B). to which the unfiltrate stream alternates at a predeterminable pressure.

4. Filter device according to one of the preceding claims, characterized in that the valve piston (1 7) has a hollow chamber (35, 37) starting from its two free end faces (31, 33). which, separated from one another via a wall part (39), each has at least one through opening (41, 43), which has passage points (45, 47, 49) in the valve housing (27) that can be assigned depending on the travel position of the valve piston (1 7). connect or lock the respective hollow chamber (35, 37).

Filter device according to one of the preceding claims, characterized in that the valve housing (27) is an integral part of a filter head (19), to which a filter pot (21) with the filter element (3) can be connected to form the filter housing, and that the passage points in Valve housings are formed from ring channels (45, 47, 49), one of which is connected to the raw side (23) of the filter element (3) and, depending on the travel position of the valve piston (1 7), another to the clean side (F).

Filter device according to one of the preceding claims, characterized in that a central ring channel (47) of a group of three ring channels merges into two tangentially opening connecting channels (51, 53) which are connected to the raw side (23) of the filter element (3). between them accommodate a collecting channel on the clean side (F) of the filter element (3), which merges into two branch lines (55, 57), one of which goes into one ring channel (45) and the other of which goes into the other ring channel (49). flows out.

Filter device according to one of the preceding claims, characterized in that in one of the maximum deflected travel positions of the valve piston (1 7) two adjacent annular channels (45, 47) of the group of three carry fluid, including the through openings (41, 43) of the valve piston (1 7) are connected to each other and the third annular channel (49) remains blocked, which in the other maximum deflected travel position of the valve piston (1 7) to the other A group of two adjacent ring channels (47, 49) belongs to one another, which are connected to each other in a fluid-carrying manner.

Filter device according to one of claims 1 to 4, characterized in that the valve slide device (15) with its valve housing (63) is integrated in the filter element (3), which, with its preferably pleated filter mat, surrounds the valve housing (63) at a predeterminable distance.

Filter device according to one of the preceding claims, characterized in that the filter element (3) accommodated in the filter housing delimits the raw side (23; 77) on the outside and the clean side (F) on the inside. 10. Filter device according to one of the preceding claims, characterized in that the valve housing (63) has passage points (69, 71, 73, 75) grouped into two pairs and that the two most widely spaced passage points (69, 75) alternately cover the raw side (77) of the filter element (3) with unfiltrate and the passage points (71, 73) of each pair adjacent to these, depending on the travel position of the valve piston (1 7), alternating with the clean side (F) of the filter element (3) connected, serve to remove the filtrate.