FILTER DEVICE

Abstract

A filter device with a filter body (1) that comprises a filter bowl (3) and a filter head (5) that is formed by a removable locking piece of the filter bowl (3), where said filter head (5) is provided with at least one connection point (15) for supplying an unfiltrate flow and at least one further connection point (27) for discharging a filtrate flow, and comprising at least one filter element (7) that contains filter material (11), where said filter element (7) is connected between the respective connection points (15, 27) and is disposed inside the filter bowl (3) for the filtration of the unfiltrate, specifically for particle contamination, where a flow directing device (33) is provided that directs the unfiltrate flow to the surface sections of the filter material (11) of the filter element (7) to provide a filtering action when the device is in operation, which is characterized in that the flow directing device comprises a molded component (33) that belongs to the filter head (5) and to which a fluid flow is applied.

Description

The invention relates to a filter device with a filter body that comprises a filter bowl and a filter head that is formed by a removable locking piece of the filter bowl, where said filter head is provided with at least one connection point for supplying the unfiltrate flow and at least one further connection point for discharging the filtrate flow, and comprising at least one filter element that contains filter material, where said filter element is connected between the respective connection points and is disposed inside the filter bowl for the filtration of the unfiltrate, specifically for particle contamination, where a flow directing device is provided that directs the unfiltrate flow to the surface sections of the filter material of the filter element to provide a filtering action when the device is in operation.

Filter devices of this kind are used in many different fields. They are widely used in technological applications for the cleaning of process fluids such as hydraulic fluids, fuel, lubricants, coolants and such like. Since filter devices are significant system components, flawless operation and filter performance is a prerequisite for trouble-free operation of the plants concerned. Considering that malfunctions that cause damage and breakdowns can lead to very high expenses, reliability is a significant factor.

In order to improve reliability and to reduce the mechanical stresses of flow forces on the filter material, which are caused in operation by the fluid flow, the prior at seeks to protect the filter material of the filter element from the direct impact of flow through a kind of baffle plate. The document DE 10 2010 005 978 A1 discloses, in a filter element of the kind described at the outset, the respective prior art with a flow directing device that is disposed upstream of the filter material in fluid flow direction with the purpose of evenly distributing the fluid flow. In this known solution the inlet for the unfiltrate flow at the filter head of the filter body is designed such that the unfiltrate flow impacts in axial direction on the top of the flow-facing end cap of the filter element, which is disposed in the filter body, and that said end cap is especially shaped to act as a flow directing device. Since the distribution effect here is dependent on the shape of the inlet in the filter head, the filter head design in the known solution is fixed to a particular arrangement of the fluid guidance that commences from the supply connection point. In other words, it is difficult to place the connecting points on the filter head in any desired position. A further disadvantage of the known solution is that the respective end cap of the filter element must be shaped especially to be able to act as a flow directing device. The associated increase of the production cost for a filter element that is designed to be particularly cheap to produce as a replacement or disposable item is a major disadvantage.

Based upon the prior art, it is the object of the invention to improve the known filter device, particularly in respect of favorable production and operating costs.

According to the invention this object is met in accordance with the characterizing part of claim 1 in a filter device of the kind described in that the flow directing device is a molded component that forms part of the filter head. Because the function of controlling the flow process is moved from the filter element to the filter head, not only in terms of impact protection for the immediate reduction of the flow stress on the filter material but also in terms of a desired distribution of the fluid flow, the advantages of controlling the flow towards the filter material can be utilized without having to use filter elements with a specially designed end cap. Apart from the achieved reduction of the production cost due to the lower production cost of the filter elements, there are also reduced consequential costs due to the operationally required filter element changes, which provide an efficient filter performance with lower overall operating costs. Since the invention does not necessitate an axial inflow to the end cap of the filter element for effective control of the flow distribution, which leads in the known solution to limitations concerning the position of the connection points on the filter head, the positioning of the connection points and the fluid guidance in the filter head is freely selectable apart from the fact that the molded component in the filter head is disposed in the fluid stream.

Thus the connection points for supply and discharge can be provided on the filter head in the positions that are most suited to the respective connection constraints.

The molded component may take the form of an inserted component or it may be an integral part of the filter head, which is particularly preferred.

In particularly advantageous exemplary embodiments the molded component is disposed in the filter head at the location of the supply connection point of the unfiltrate in such a way that it forms a type of flow divider and provides at least two flow directing surfaces that divert the unfiltrate flow, which enters via the connection point, into diverging flow directions within an inflow chamber that is open towards the filter bowl. To this extent the molded component not only acts as impact protection for the filter material, but also forms with the diverging flow directing surfaces a flow that spreads in the inflow chamber in form of a flow line, so that the unfiltrate flows distributed and homogenous from the inflow chamber to the outer circumferential area of the filter material.

A particularly advantageous arrangement may be where, with the filter element oriented vertically, an end cap of the filter element, which encloses the plain cylindrical outer surface of the filter material, forms with an outer annular surface the bottom of the inflow chamber, from which the flow path of the unfiltrate stream extends via the circumferential edge of the annular surface into the chamber that surrounds the outer surface of the filter material. The end cap may form a further flow directing surface with the surface of the annular surface, advantageously in form of a conical surface that slopes towards the circumferential edge of the end cap, for example.

In advantageous exemplary embodiments the connection point for the unfiltrate flow is formed by a lateral inlet port in the filter head, in which the molded component takes the shape of a fin which, facing the inlet port and spanning its cross-section, extends in the inflow chamber vertically to the upper end cap of the filter element, which in operational orientation extends vertically.

At the annular surface that forms the bottom of the inflow chamber, the upper end cap of the filter element may be provided with an integral projection that is formed such that, as an additional component of the flow directing device, it forms a continuous extension of the flow directing surfaces of the molded component when the filter element is in operational orientation. This ensures that the flow is directed optimally over the entire length of the inflow chamber.

In particularly advantageous exemplary embodiments, in which the element seat for the filter element inside the filter head is provided by a receptacle that takes the form of a pipe socket, in which said receptacle engages with a central opening in the upper end cap of the filter element, oriented in operating position, to enable the discharge of the filtrate stream from the internal filter cavity of the filter element, the vane-like molded component of the flow directing device may advantageously be molded to the outside of the pipe socket.

In exemplary embodiments of this kind the arrangement may advantageously be such that the molded component on that end which, with the filter element in operating orientation, abuts the shoulder of the end cap, and the shoulder of the end cap is provided with interacting positioning elements, which predetermine a rotating position for the operating position of the filter element. This not only ensures the uninterrupted continuation of the flow directing surfaces of the molded component by the shoulder, but the positioning elements on the molded component and on the shoulder may be formed such that, like in a lock and key system, only a filter element with suitable specifications can be brought into operating position on the element seat.

In particularly advantageous exemplary embodiments, in which the inflow chamber is designed to have a greater height in the part that is adjacent to the inlet port than in the remaining part that is separated from it, the arrangement may be such that, with clearance to the molded component, inclined surfaces, similar to those of parts of a bell-shaped mantle that widens out in the direction towards the end cap, form additional flow directing surfaces that guide the unfiltrate flow towards the circumferential section of the annular surface of the filter element end cap. This makes it possible to achieve a particularly homogenous flow towards the filter material.

To achieve the best possible fluid guidance at the lowest possible pressure loss, the fin that forms the molded component of the filter head may be provided with a rounded leading edge, as well as flat, diverging, lateral flow directing surfaces that extend from said leading edge, where said flow directing surfaces adjoin the pipe socket of the filter head.

Another object of the invention is also a filter element that is provided in particular for a filter device according to one of the claims 1 to 11 and which exhibits the characteristics of claim 12.

The invention will now be explained in detail by way of the exemplary embodiments depicted in the drawing.

Shown are in:

FIG. 1 a side elevation of an exemplary embodiment of the filter device according to the invention, with a view of the connection point for the supply of the unfiltrate flow;

FIG. 2 a longitudinal section of the exemplary embodiment rotated by 90° compared to that of FIG. 1;

FIG. 3 a perspective view of the exemplary embodiment, depicting a half-section view with vertically extending sectional planes;

FIG. 4 a diagram showing the exemplary embodiment half in side elevation and half in longitudinal section;

FIG. 5 a separately shown, perspective view of the underside of the exemplary embodiment of the filter head;

FIG. 6 a perspective view of the filter head depicting the fluid inflow chamber formed on the underside;

FIG. 7 the portion of the filter head designated with VII in FIG. 6, shown enlarged compared to FIG. 6;

FIG. 8 a perspective view of the separately drawn filter head, depicting the top end and the connection point for the filtrate flow;

FIG. 9 a view of the underside of the filter head;

FIG. 10 a cross-sectional view of the filter head according to line X-X shown in FIG. 9;

FIG. 11 a perspective view of the upper end cap, which relates to the filter head, of a filter element that is to be inserted into the filter bowl of the exemplary embodiment;

FIG. 12 an enlarged representation of the portion of the end cap designated in FIG. 11 with XII;

FIG. 13 a plan view of the end cap;

FIG. 14 a cross-sectional view of the end cap along line XIV-XIV of FIG. 13;

FIG. 15 a perspective view of a modified embodiment of the upper end cap of the filter element;

FIG. 16 a plan view of the end cap of FIG. 15;

FIG. 17 a cross-sectional view of the end cap along line XVII-XVII of FIG. 16, and

FIG. 18 a perspective view of the underside of the end cap of FIG. 15.

The exemplary embodiment of the filter device depicted in the figures comprises a filter body designated overall with 1 with a plain cylindrical filter bowl 3 that is closed at the bottom and a filter head 5 that forms the upper end of said filter bowl 3. Said filter head 5 is attached via thread 9 to filter bowl 3 to enable the insertion and removal of a replaceable filter element 7 from filter body 1, in which the sealing ring 10 provides the seal. The filter element 7 is constructed in a way that is common to filter devices of this kind and comprises a filter material 11 in form of a hollow cylinder, which surrounds an inner filter cavity 13 that forms the filtrate chamber, which is separated by the filter material 11 from the unfiltrate chamber 14 that surrounds the outside of filter element 7. When in operation, unfiltrate is supplied via an inflow chamber 17 through an unfiltrate connection point 15 that is located on filter head 5 in housing 1. As is common practice in filter elements of this kind, the filter material 11 of the filter element 7 is cased by a lower end cap 19 and an upper end cap, which is designated with the number 21 in a first embodiment and is depicted separately in the FIGS. 11, 13 and 14. Said upper end cap 21 comprises a central opening 23, which is in fluid connection with a passage 25 when the filter element 7 is disposed in operating orientation in housing 1. Said passage 25 extends similar to a pipe bent at right angles inside the filter head 5 through the inflow chamber 17 to the connection point 27 for the discharge of the filtrate flow, which exits from the internal filter cavity 13. The connection point 27 is located diametrically opposite to the connection point 15 for the supply of the unfiltrate flow. To provide for the fluid connection between passage 25 of the filter head 5 and the internal cavity 13 of filter element 7, the filter head 5 is provided with a pipe socket 29 that passes through the inflow chamber 17. Said pipe socket 29 forms the element seat for the filter element 7 which, when filter element 7 is in operating orientation, engages with the opening 23 of end cap 21, in which an O-ring 31 that is located on the outside of pipe socket 29 provides the seal (see in particular FIG. 7).

As can be most clearly seen in FIGS. 3, 6 and 7, the main part of the flow directing device is a fin 33, which extends along the outside of the pipe socket 29 in axial direction in form of a radial protrusion, which is aligned with the inlet port 16 at the connection point 15 for the inflow of the unfiltrate stream and spans the entire opening cross-section of port 16 of the connection point 15. The fin 33 extends in inflow chamber 17 vertically in the direction of the upper end cap 21 of the in operation vertically oriented filter element 7. In the exemplary embodiment shown, the fin 33 is an integral, molded component of filter head 5. It is possible to provide a corresponding molded component also as a separate part to be inserted. As is shown most clearly in FIGS. 6, 7 and 9, the fin 33 is provided, adjacent to a rounded leading edge 35, with lateral flow directing surfaces 37 that extend, diverging from each other, towards pipe socket 29. With this contour the fin 33 forms a flow divider for the inflowing unfiltrate, which spreads the flow laterally in inflow chamber 17. As depicted in FIGS. 3 and 4, and as is most clearly apparent from a comparison of FIGS. 9 and 10, the inflow chamber 17 has the greatest height in the inlet section that is adjacent to the inlet port 16, from which it drops via an inclined surface 39 to a reduced height, in which the height of the inflow chamber 17 is limited by a flat cover 41. This forms a pocket-like inflow opening 45 between the section 43 that is adjacent to the inlet port 16 and the cover 41. Located in this space and with clearance to the fin 33 are additional flow directing surfaces 47 disposed that have the form of parts of a bell-shaped mantle that widens out towards the bottom (see in particular FIG. 6).

With the filter element 7 in operational orientation it forms with the upper side of the upper end cap 21 the bottom of the inflow chamber 17. As is most clearly shown in FIGS. 11, 13 and 14, the upper side of the end cap 21 has the shape of a conical surface 49 that drops off to the outside and surrounds the axially protruding rim 51, which in turn surrounds the central opening 23. The conical surface 49 which, with the filter element 7 in operating orientation, forms a bottom surface of the inflow chamber 17, acts at the same time as a further flow directing surface, which allows the unfiltrate stream to flow away homogenized into the unfiltrate chamber 14 via its circumferential rim.

As is most apparent from FIG. 7, the pipe socket 29 is provided with a flat end face 53, which is, compared to end rim 52 that is surrounded by the sealing ring 31, slightly offset towards the back. Said end face 53 extends also radially as the end section of fin 33. A radially protruding tongue 55 is located in this end section. With the filter element in operating orientation, the end cap 21 with its flat rim 51 rests flush against the end face 53 of the pipe socket 29. On the end cap 21 at the rim 51 of opening 23, a radially projecting nose 57 is formed which, when in operating orientation, is aligned with the fin 33 on pipe socket 29 and is provided with a recess 59 to engage with the tongue 55. In this way the tongue 55 and the recess 59 are forming locating elements of a locking arrangement that predetermines the rotational position of the filter element 7. At the same time the nose 57 is externally shaped such that it forms a smooth continuation of the flow directing surfaces 37 of fin 33. Thus the formed flow divider extends within the inflow opening 45 from the upper end of the inflow chamber 17 up to the flow directing surface formed by the conical surface 49 of end cap 21.

The FIGS. 15 to 18 depict a modified embodiment of the upper end cap designated with 20. The only difference to the end cap 21 lies in that, instead of providing a full annular mantle, the upper side of which forms a conical surface 49 that surrounds the central opening 23, a collar of radial fins 61 is formed that protrude from a flat bottom 63 of the end cap 20. Besides the material savings achieved compared to a solid body, the collar of fins can contribute as a kind of guide vane for the homogenization of the flow, for example at low unfiltrate velocities. The above described receiving socket does not have to be plain cylindrical; rather, it may have any desired shape, for example a polynomial, an orbiform curve or an oval etc.

Claims

1. A filter device with a filter body (1) that comprises a filter bowl (3) and a filter head (5) that is formed by a removable locking piece of the filter bowl (3), where said filter head (5) is provided with at least one connection point (15) for supplying an unfiltrate flow and at least one further connection point (27) for discharging a filtrate flow, and comprising at least one filter element (7) that contains filter material (11), where said filter element (7) is connected between the respective connection points (15, 27) and is disposed inside the filter bowl (3) for the filtration of the unfiltrate, specifically for particle contamination, where a flow directing device (33) is provided that directs the unfiltrate flow to the surface sections of the filter material (11) of the filter element (7) to provide a filtering action when the device is in operation, characterized in that the flow directing device comprises a molded component (33) that belongs to the filter head (5) and to which a fluid flow is applied.

2. A filter device according to claim 1, characterized in that the molded component (33) is an integral part of the filter head (5).

3. A filter device according to claim 1, characterized in that the molded component (33) is disposed in the filter head (5) at the location of the supply connection point (15) of the unfiltrate in such a way that it forms a type of flow divider and provides at least two flow directing surfaces (37) that divert the unfiltrate flow, which enters via the connection point (15), into diverging flow directions within an inflow chamber (17) that is open towards the filter bowl (3).

4. A filter device according to claim 1, characterized in that, with the filter element oriented vertically, an end cap (21) of the filter element, which encloses the plain cylindrical outer surface of the filter material (11), forms with an outer annular surface (49) the bottom of the inflow chamber (17), from which the flow path of the unfiltrate stream extends via the circumferential edge of the annular surface (49) into the chamber (14) that surrounds the outer surface of the filter material (11).

5. A filter device according to claim 1, characterized in that the annular surface of end cap (21) acts as a further flow directing surface in the form of a conical surface (49) that drops away towards the circumferential rim.

6. A filter device according to claim 1, characterized in that the connection point (15) for the unfiltrate flow is formed by a lateral inlet port (16) in the filter head (5), in which the molded component takes the shape of a fin (33) which, facing the inlet port (16) and spanning its cross-section, extends in the inflow chamber (17) vertically to the upper end cap (21) of the filter element (7), which in operational orientation extends vertically.

7. A filter device according to claim 1, characterized in that the upper end cap (21) of the filter element (7) is provided with an integral projection (57) that protrudes from the annular surface (49) that forms the bottom of the inflow chamber (17) in such a way that, as an additional component of the flow directing device, with the filter element (7) in operational orientation, it is aligned with the molded component (33) and forms a continuous extension of the flow directing surfaces (37) of the molded component (33).

8. A filter device according to claim 1, characterized in that the element seat for the filter element (7) in the filter head (5) is provided by a receptacle that takes the form of a pipe socket (29), in which said receptacle engages with a central opening (23) in the upper end cap (21) of the filter element (7), oriented in operating position, to enable the discharge of the filtrate stream from the internal filter cavity (13) of the filter element (7), and that the vane-like, molded component (33) is molded to the outside of the pipe socket (29).

9. A filter device according to claim 1, characterized in that the molded component (33) on that end which, with the filter element (7) in operating orientation, abuts the shoulder (57) of the end cap (21), and the shoulder (57) of the end cap (21) is provided with interacting positioning elements (55, 59), which predetermine a rotating position for the operating position of the filter element (7).

10. A filter device according to claim 1, characterized in that the inflow chamber (17) is designed to have a greater height in the part that is adjacent to the inlet port (16) than in the remaining part that is separated from it, and that, with clearance to the molded component (33), inclined surfaces (47), similar to those of parts of a bell-shaped mantle that widens out in the direction towards the end cap (21), form additional flow directing surfaces that guide the unfiltrate flow towards the circumferential section of the annular surface (49) of the end cap (21) of the filter element (7).

11. A filter device according to claim 1, characterized in that the fin (33) that forms the molded component of the filter head is provided with a rounded leading edge (35), as well as flat, diverging, lateral flow directing surfaces (37) that extend from said leading edge (35), where said flow directing surfaces (37) adjoin the pipe socket (29) of the filter head (5).

12. A filter element (7), provided in particular for a filter device according to claim 1, characterized in that at least one of its end caps (21) is provided with a nose (57) that forms an additional part of the flow directing device, which comprises as the main part a molded component (33) that belongs to the filter head (5) of the filter housing (1) of the filter device.