DE202013012843U1 - Liquid filters, in particular for fuel - Google Patents

Abstract

Liquid filter with an annular filter element (6) through which a radial flow can flow from the outside in a filter housing (2), characterized in that a water separating sieve (11) is inserted into the filter element (6), which is formed separately from the filter element (6) and with the filter element (6) or a component arranged on the filter element (6) is connected, and that the water separating screen (11) comprises a screen fabric (23) and a fabric support (22), the fabric support (22) in the area between the end faces of the Screen fabric (23) exclusively has longitudinal struts (24) which extend at least substantially in the direction of the longitudinal axis (26) of the water separating screen (11) and are designed to be radially elastic, and the screen fabric (23) on the outside of the longitudinal struts (24) of the water separating screen ( 11) is arranged.

Description

Technical field

The invention relates to a liquid filter, in particular for fuel, according to the preamble of claim 1.

State of the art

From the WO 2004/082804 A1 a filter system for diesel fuel is known which has an annular particle filter in a filter housing, which is also preceded by an annular coalescer element. Via the coalescer element, water droplets dispersed in the fuel are enriched to form larger droplets in order to facilitate water separation. The coalescer element and the filter element are mounted around a central tube, which is arranged centrally in the receiving space of the filter housing and is used to discharge the cleaned fuel.

In the DE 20 2011 002 684 U1 describes a filter for insertion into a fuel tank, which has a filter sock made of a fabric, which is supported by web-like stiffening elements that are flexibly deformable. This is to ensure that when the filter is inserted into a curved filler neck, the filter can follow the course without damage. However, the stocking-shaped filter is only used for particle filtering, water separation cannot be achieved with it.

WO 2012/097851 A1 relates to a diesel filter with water separation, which has a radially from the outside inward flowable particle filter, in which a cylindrical hydrophobic strainer is arranged, with which the outlet for cleaned fuel is fluidly connected, with a separation gap being present between the particle filter element and the hydrophobic strainer. The water separated on the hydrophobic sieve flows downward through a passage into a collecting space. Furthermore, a tube is arranged in the hydrophobic sieve in such a way that it functions as a riser or overflow tube and thus enables rapid venting.

US 2004/0163690 A1 relates to a filter arrangement for a dishwasher, which consists of several filters. The "third filter" has between its front ends only longitudinal struts that support the screen fabric, the screen fabric is apparently attached to the inside of the struts.

Beyond that DE 10 2010 030 987 A1 and the DE 601 28 690 T2 mentioned, which relate to further fuel filters with water separation, which are characterized by an increase in the residence time of the fuel on the hydrophobic screen fabric or by a conical design of the screen fabric.

Disclosure of the invention

The invention has for its object to provide a liquid filter with simple constructive measures with which water droplets can be effectively separated dispersively separated over a long period of operation.

This object is achieved with the features of claim 1. The subclaims indicate appropriate further training.

The liquid filter according to the invention is advantageously a fuel filter, preferably a diesel fuel filter. However, an application is also possible, for example for the filtration of hydraulic oil.

The liquid filter has an annular filter element in a filter housing, which serves in particular as a particle filter and through which the fluid to be cleaned flows radially from the outside inwards. The interior of the hollow cylindrical filter element forms the clean room through which the cleaned fluid is drained axially. A center tube can be inserted into the clean room, which gives the filter element of the filter element, which is, for example, in the form of a fold, additional stability.

A water separating screen is inserted into the filter element of the liquid filter, which is formed separately from the filter element and is connected to the filter element or to a component arranged on the filter element. On the water separating sieve, water droplets are separated, which are contained in the liquid to be cleaned, that is to say, for example, the fuel or the hydraulic oil. The clean room in the filter element can be axially flow-connected at one end to a water collection chamber which is arranged in the filter housing and into which the separated water is drained off from the water separating screen. The cleaned fluid, on the other hand, is advantageously discharged from the clean room of the filter element via a liquid outflow line arranged axially at the other end. This allows, for example, an arrangement of the liquid filter with the water collecting space in the area of the filter housing lying at the bottom, whereas the cleaned liquid is drained axially upward from the clean room. The water taken up in the water collecting space can be drained out of the filter housing, for example, via a valve. The outflow more isolated Water droplets from the water separating sieve into the water collecting space thus take place in the direction of the weight of the water droplets.

The water separating screen comprises a screen fabric and a fabric support on which the screen fabric is held and which gives the screen fabric a defined shape, for example a cylindrical shape or a conical shape. The water separating sieve is located on the clean side of the filter element, it is inserted in the cylindrical clean room of the filter element. If a central tube is arranged on the inner wall of the clean room on the filter medium of the filter element, the central tube surrounds the water separating sieve. In particular, there is a gap between the water separating sieve and the central tube, e.g. B. of at least 5 mm.

The fabric carrier extends between the end faces of the screen fabric and in this area has only longitudinal struts which extend at least substantially in the direction of the longitudinal axis of the filter element or of the water separating screen arranged coaxially to the filter element. Due to the at least substantially axial alignment of the longitudinal struts in the direction of the longitudinal axis, the angle of the longitudinal struts to the longitudinal axis is less than 45 °. It can be expedient to align the longitudinal struts exactly in the direction of the longitudinal axis or at a small angle of, for example, a maximum of 10 ° or a maximum of 20 °.

Only the longitudinal struts of the fabric carrier run in the area between the end faces of the screen fabric, but no cross struts. By dispensing with cross struts, the structure of the fabric carrier has a high degree of radial elasticity and can in particular be compressed radially inwards. This enables the screen fabric, which is carried by the fabric support and is located on the outside of the longitudinal struts of the water separating screen, to also escape radially inward at a correspondingly high pressure which is applied radially to the outside of the water separating screen. Such an increased pressure exists, for example, when the liquid filter is used for diesel filtration at low temperatures and paraffins are separated from the diesel fuel, as a result of which the screen fabric is subjected to force radially from the outside inwards. The radially elastic yielding of the longitudinal struts and the screen fabric prevents tearing of the screen fabric.

As soon as the external pressure subsides, the water separating sieve returns to its starting position by the radially elastic longitudinal struts returning to their starting position. The screen fabric, which is arranged on the outside of the longitudinal struts, also returns to the starting position.

In an embodiment not according to the invention, an arrangement of the screen fabric on the inside of the longitudinal struts is also possible. In this case, it may be expedient to connect the screen fabric to the longitudinal struts at least at certain points. If the screen fabric is arranged on the outside of the longitudinal struts, on the other hand, it is not absolutely necessary to connect the screen fabric to the longitudinal struts, even if this is fundamentally possible.

The fabric carrier is advantageously made of plastic. Furthermore, it is expedient for the fabric carrier to have a carrier ring or collar on each end face of the water separating sieve and for the longitudinal struts to run between and be connected to the carrier rings. It is in particular possible to form the end-face carrier rings and the intermediate longitudinal struts in one piece. The front carrier rings are each connected to the screen mesh. Via one of the carrier rings, the water separating sieve is to be connected, for example, to an end plate which is arranged on an end face of the filter element.

It may be expedient to keep the number of longitudinal struts relatively small in order to ensure sufficient radial elasticity of the tissue carrier and also to minimize the area which is covered by the longitudinal struts and is therefore not available for the passage of the liquid to be cleaned to keep. For example, it is sufficient to provide four longitudinal struts evenly distributed over the circumference in the fabric carrier.

According to a further expedient embodiment, a coalescer element is arranged in the liquid filter in addition to the filter element, which element is expediently integrated into the filter element. The fluid to be cleaned is a dispersive mixture of two liquids, for example fuel with dispersively stored water, which are to be separated from one another. With the help of the coalescer element, fine water droplets can be brought together to form larger droplets, but without causing separation. Thus, only larger water droplets are generated in the coalescer element, which are separated on the water separating sieve, which is located in the clean room, after flowing through the coalescer element. The coalescer element is preferably arranged on the clean side of the filter element, in particular between the radial side Inside of the filter medium of the filter element and the center tube.

It may be expedient to provide a sealing element between the water separating sieve and the component on the filter element on which the water separating sieve is held. As far as the water separating screen is connected to the end plate, the sealing element can be arranged between a collar or carrier ring and the end plate. The collar or carrier ring is preferably located on the end face of the water separating sieve. The sealing element between the water separating sieve and the component of the filter element is either formed in one piece with the collar or carrier ring, for example as a sealing lip formed on the collar or carrier ring, or as a separately formed sealing element in the form of a sealing ring.

Figure list

• 1 in perspektivischer Ansicht ein Flüssigkeitsfilter zur Kraftstofffiltration,
• 2 einen Schnitt längs durch den Flüssigkeitsfilter mit eingezeichneten Strömungspfeilen zur Kennzeichnung des Strömungswegs,
• 3 in perspektivischer, teilgeschnittener Ansicht ein Filterelement, welches Bestandteil des Flüssigkeitsfilters ist, mit einem im innenliegenden Reinraum angeordneten Wasserabscheidesieb,
• 4 in einer weiteren, teilgeschnittenen Darstellung das Filterelement,
• 5 eine vergrößerte Ansicht des Teils V aus 4,
• 6 das Wasserabscheidesieb in Seitenansicht,
• 7 das Wasserabscheidesieb im Längsschnitt,
• 8 das Wasserabscheidesieb in perspektivischer Ansicht.

Further advantages and expedient designs can be found in the further claims, the description of the figures and the drawings. Show it:

• 1 a perspective view of a liquid filter for fuel filtration,
• 2nd 3 shows a section along the liquid filter with flow arrows drawn in to identify the flow path,
• 3rd a perspective, partially sectioned view of a filter element, which is part of the liquid filter, with a water separating sieve arranged in the internal clean room,
• 4th in a further, partially sectioned illustration the filter element,
• 5 an enlarged view of part V. 4th ,
• 6 the water separating screen in side view,
• 7 the water separating sieve in longitudinal section,
• 8th the water separating sieve in a perspective view.

The same components are provided with the same reference symbols in the figures.

Embodiment (s) of the invention

In 1 is a liquid filter in perspective 1 for the filtration of fuel, preferably diesel fuel. The liquid filter 1 points in a filter housing 2nd a filter element for filtering the fuel. In the upper, front area of the filter housing 2nd there is a heater 3rd , in which the fuel supplied is preheated before it reaches the filter element in the filter housing 2nd is forwarded. Also in the upper area of the filter housing 2nd there is a radial inflow line 4th for the supply of unfiltered fuel and a radial discharge line 5 for the discharge of the filtered fuel.

In 2nd is the liquid filter 1 shown in longitudinal section. In the filter housing 2nd is the ring-shaped filter element 6 recorded, which is flowed through radially from the outside inward by the fluid to be filtered. Accordingly, the cylindrical interior forms in the filter element 6 the clean room 7 , from which the cleaned fluid is drained axially.

In the clean room 7 of the filter element 6 is a center or support tube 8th used, which is preferably made of plastic and the filter medium of the filter element 6 supports and gives it stability. The middle tube 8th dresses the clean room 7 out.

On the radially inner side of the filter medium of the filter element 6 there is a coalescer element 9 that is radially inward from the center tube 8th is limited. In the coalescer element 9 there is a coalescence or agglomeration of finely divided water droplets in the fuel, so that these accumulate to form larger droplets.

The filter housing is located in the lower area near the floor 2nd a water collection room 10th , in which water is collected, which is separated during the filtration of the fluid. The collected water can be removed from the water collection chamber via a bottom opening and a valve 10th are derived in the filter housing.

In the clean room 7 is a water separating sieve 11 used, which is hollow cylindrical and has an outer diameter that is smaller than the inner diameter of the center tube 8th , so that an intermediate annular space is formed. The water separating sieve 11 extends axially as well as the center tube 8th over the entire length of the clean room 7 or the filter element 6 . But it is also possible that the water separating sieve 11 only over part of the length of the clean room 7 or the filter element 6 extends. On the outer surface of the water separating sieve 11 the water droplets, which are carried in the fuel, are separated. The separated water droplets are, as shown with the arrows pointing vertically downwards, over the lower axial face of the clean room 7 in the water collection room 10th derived.

The wall of the water separating sieve 11 has a plurality of passage openings through which the cleaned fuel from the annular space between the center tube 8th and water separating sieve 11 radially inwards into the interior of the water separating sieve 11 can flow through. In particular, has a screen fabric 23 ( 6 to 8th ) of the water separating sieve 11 Meshes with a defined mesh size of z. B. 10 to 30 microns. The cleaned fuel, which has been freed of water droplets, is then drained off axially via the axially upper end of the clean room 7 which with the discharge line 5 is connected to the flow.

In 3rd is the filter element 6 shown in perspective and partially sectioned view. The filter medium 12th of the filter element 6 is designed as a pleated filter and has an end plate on both ends 13 , 14 edged. In the area of the upper end plate 6 , through the central opening of the cleaned fluid from the clean room 7 is discharged, the water separating sieve has 11 a radially widened collar or carrier ring 15 on, the snap or snap hook 16 latching with the end plate 13 connected is. The locking hooks 16 are on the inboard side of the end plate 13 molded or in one piece with the end plate 13 trained (see also 4th , 5 ). When connected, they engage behind the locking hooks 16 a circumferential, radially outer ring shoulder on the collar or carrier ring 15 .

How in particular 5 can be seen adjacent to the free end face and in the radially outer area on the collar or carrier ring 15 a sealing lip 17th molded on the radially inner side of the locking hook 16 is present. The locking hooks 16 can also be used as a continuous circumferential locking ring on the underside of the end plate 13 be trained. Over the sealing lip 17th there is a flow-tight seal between the radially outer clean side with water-containing fuel and the radially inner clean side with fuel without water.

The end plate 13 has an axially projecting support collar on its axially outwardly facing end face 20 on which a lid 18th is put on. On the radially inner side of the support collar 20 there is a sealing ring 19th that is radially inward, like 3rd on a section of the end plate 13 supports.

How 5 can also be seen, the free end face of the collar 15 in the assembled state immediately below the end plate 13 . The water separating sieve must be installed 11 axially from the opposite side into the clean room 7 or the center tube 8th be introduced.

In the 6 to 8th is the water separating sieve 11 shown in isolation. The water separating sieve 11 includes a tissue carrier 22 , which is made of plastic, and a mesh 23 which from the fabric carrier 22 is held and carried. The tissue carrier 22 has two end collars or carrier rings 15 , 25th on and between the carrier rings 15 , 25th trending, in the direction of the longitudinal axis 26 extending struts 24th . The longitudinal struts 24th are in one piece with the front carrier rings 15 , 25th educated. The longitudinal axis 26 of the cylindrical water separating sieve 11 in the assembled state coincides with the longitudinal axis of the liquid filter.

The screen mesh 23 lies on the radially outer outside on the longitudinal struts 24th and is on the front with each carrier ring 15 , 25th connected. In the area between the carrier rings 15 , 25th points out the fabric carrier 22 only the side members 24th on, but no connecting cross struts, so that there is radial elasticity and the longitudinal struts 24th , which are preferably made of plastic, can yield elastically radially from the outside inwards if the external pressure is correspondingly high. This also enables the screen mesh 23 to deform radially inward when pressure is applied. This significantly reduces the risk of the screen mesh tearing.

A total of four longitudinal struts are distributed over the circumference 24th in the tissue carrier 23 provided, each exactly in the direction of the longitudinal axis 26 run and are evenly distributed over the circumference. The longitudinal struts 24th have only a relatively small thickness, on the one hand to ensure the desired radial elasticity and on the other hand to limit as little as possible the flow area available on the screen fabric for the flow of the fluid to be cleaned.

After the radially external pressure has been eliminated, the longitudinal struts can 24th return through their own elasticity to the starting position, in which the longitudinal struts 24th have a straight course. With the return to the starting position, the sieve cloth becomes too 23 moved back to the starting position.

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• WO 2004/082804 A1 [0002]
• DE 202011002684 U1 [0003]
• WO 2012/097851 A1 [0004]
• US 2004/0163690 A1 [0005]
• DE 102010030987 A1 [0006]
• DE 60128690 T2 [0006]

Claims (12)

Liquid filter with an annular filter element (6) through which a radial flow can flow from the outside in a filter housing (2), characterized in that a water separating sieve (11) is inserted into the filter element (6), which is formed separately from the filter element (6) and with the filter element (6) or a component arranged on the filter element (6) is connected, and that the water separating screen (11) comprises a screen fabric (23) and a fabric support (22), the fabric support (22) in the area between the end faces of the Screen fabric (23) exclusively has longitudinal struts (24) which extend at least substantially in the direction of the longitudinal axis (26) of the water separating screen (11) and are designed to be radially elastic, and the screen fabric (23) on the outside of the longitudinal struts (24) of the water separating screen ( 11) is arranged. Liquid filter after Claim 1 , characterized in that the longitudinal struts (24) extend exactly in the direction of the longitudinal axis (26) of the water separating sieve (11). Liquid filter after Claim 1 or 2nd , characterized in that a central tube (8) is inserted into the inside of the clean room (7) in the filter element (6), which surrounds the water separating sieve (11). Liquid filter according to one of the Claims 1 to 3rd , characterized in that four longitudinal struts (24) are arranged over the circumference of the water separating sieve (11). Liquid filter according to one of the Claims 1 to 4th , characterized in that the fabric carrier (22) has a carrier ring (15, 25) on each end face of the water separating sieve (11) and the longitudinal struts (24) run between the carrier rings (15, 25) and are connected to them. Liquid filter according to one of the Claims 1 to 5 , characterized in that the clean room (7) in the filter element (6) is flow-connected to a water collection chamber (10) in the filter housing (2). Liquid filter according to one of the Claims 1 to 6 , characterized in that a coalescer element (9) is arranged adjacent to the filter element (6). Liquid filter according to one of the Claims 1 to 7 , characterized in that the water separating sieve (11) can be connected to an end plate (13) which is arranged on an end face of the filter element (6). Liquid filter according to one of the Claims 1 to 8th , characterized in that the water separating sieve (11) is cylindrical. Liquid filter according to one of the Claims 1 to 8th , characterized in that the water separating sieve (11) is conical. Liquid filter after Claim 1 to 10th , characterized in that the liquid filter is a liquid filter for fuel. Liquid filter after Claim 11 , characterized in that the liquid filter is a diesel fuel filter.

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