Coalescing element of a water separator device, and water separator device

Abstract

A coalescing element for a water separator device for fuel is provided with at least one coalescing medium that separates water contained in the fuel from the fuel. The coalescing element is arranged in a housing of the water separator device such that the coalescing element separates at least one fuel inlet of the housing from at least one fuel outlet of the housing. The at least one coalescing medium is arranged in a flow path of the fuel from the at least one fuel inlet to the at least one fuel outlet. The at least one coalescing medium contains at least one sponge-like coalescing material suitable for coalescing water. The coalescing element is used in fuel filters such as diesel fuel filters of an internal combustion engine.

Claims

1. A coalescing element for a water separator device for fuel, the coalescing element comprising at least one coalescing medium configured to separate water contained in a fuel from the fuel, wherein the coalescing element is configured to be arranged in a housing of the water separator device such that the coalescing element separates at least one fuel inlet of the housing from at least one fuel outlet of the housing and the at least one coalescing medium is arranged in a flow path of the fuel from the at least one fuel inlet to the at least one fuel outlet, wherein the at least one coalescing medium comprises at least one sponge-like cloth coalescing material comprising cotton fibers, viscose and a pore forming agent of Glauber's salt crystals embedded into the cotton fibers, the embedded Glauber's salt crystals forming pores in the at least one sponge-like cloth coalescing material, a size of the Glauber's salt crystals determining a size of the pores in the at least one sponge-like cloth coalescing material; wherein the viscose bonds the cotton fibers together, holding the at least one sponge-like cloth coalescing material together; wherein the cotton fibers, viscose and embedded Glauber's salt crystals form multiple contiguous areas of coalescing material that are bonded to each other, forming holes or pores between the contiguous areas, the holes or pores configured for catching water droplets and for passage of the water, wherein the sponge-like cloth coalescing material can swell so the absorption capacity for water is increased, wherein the at least one coalescing medium is suitable for coalescing water wherein the at least one coalescing material is produced from a mass containing the pore forming agent, wherein the pore forming agent has been removed from the at least one coalescing material when finished.

2. The coalescing element according to claim 1, further comprising at least one filter medium.

3. The coalescing element according to claim 1, wherein the at least one coalescing material is comprised of a layered fabric sponge cloth material.

4. The coalescing element according to claim 1, wherein the at least one coalescing material is comprised of a sponge cloth material produced by a viscose method.

5. The coalescing element according to claim 4, wherein the viscose method is a cellulose xanthate method.

6. The coalescing element according to claim 1, wherein the at least one coalescing medium is a hollow body.

7. The coalescing element according to claim 1, further comprising at least one hydrophobic fuel-permeable separating medium in the form of a hollow body for separation of water contained in the fuel, wherein the at least one separating medium is a hydrophobic screen fabric arranged in the flow path of the fuel downstream of and spaced apart away from the at least one coalescing medium such that at least one precipitation gap for separated water is formed between the at least one coalescing medium and the at least one separating medium.

8. The coalescing element according to claim 7, wherein the at least one separating medium surrounds the at least one coalescing medium or is arranged in an interior of the at least one coalescing medium.

9. The coalescing element according to claim 1, wherein the at least one coalescing medium, at least one filter medium, and at least one separating medium are coaxially arranged.

10. The coalescing element according to claim 1, wherein the coalescing element is a round filter element.

11. A water separator device comprising: a housing comprising at least one fuel inlet for a fuel to be treated, at least one fuel outlet for treated fuel, and at least one water outlet for water separated from the fuel; a coalescing element according to claim 1 having at least one coalescing medium for separation of water contained in the fuel, the at least one coalescing medium arranged in a flow path of the fuel from the at least one fuel inlet to the at least one fuel outlet.

12. The water separator device according to claim 11, further comprising at least one filter medium arranged in the housing.

13. The water separator device according to claim 11, wherein the housing is openable and the at least one coalescing medium is arranged exchangeably in the housing.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further advantages, features, and details of the invention result from the following description in which an embodiment of the invention will be explained in more detail with the aid of the drawing. A person of skill in the art will expediently consider the features disclosed in the drawing, the description, and the claims in combination also individually and combine them to meaningful further embodiments.

(2) FIG. 1 shows a schematic longitudinal section of a fuel filter with an exchangeable three-stage filter element that comprises a coalescing medium of a sponge cloth material;

(3) FIGS. 2 and 3 show schematic illustrations of the sponge cloth material of the fuel filter of FIG. 1, viewed in the flow-through direction of the fuel;

(4) FIGS. 2A and 3A are original scanning electron microscope images of FIGS. 2 and 3, showing the sponge cloth material of the fuel filter of FIG. 1, viewed in the flow-through direction of the fuel;

(5) FIG. 4 shows a schematic illustration of the sponge cloth material of the fuel filter of FIG. 1, viewed transverse to the flow-through direction of the fuel;

(6) FIG. 4A is an original scanning electron microscope image of FIG. 4 showing the sponge cloth material of the fuel filter of FIG. 1, viewed transverse to the flow-through direction of the fuel;

(7) FIG. 5 is a schematic illustration of a coalescing medium of a fleece known in the prior art, viewed in the flow-through direction of the fuel; and

(8) FIG. 5A is an original scanning electron microscope image of FIG. 5 showing a coalescing medium of a fleece known in the prior art, viewed in the flow-through direction of the fuel.

(9) In the Figures, same components are provided with same reference characters.

DESCRIPTION OF PREFERRED EMBODIMENTS

(10) In FIG. 1, a fuel filter 10 of a fuel system of an internal combustion engine of a motor vehicle is illustrated in longitudinal section. The fuel filter 10 serves for purifying the fuel, for example, diesel fuel, used in operation of the internal combustion engine. The fuel contains an additive for improving the properties of the fuel. Moreover, the fuel filter 10 serves for separating water that is contained in the fuel.

(11) The fuel filter 10 comprises a two-part housing 12 with a cup-shaped filter bowl 14 and a filter cover 16 that is separably arranged on the filter bowl 14. An annular seal 17 is arranged between the filter bowl 14 and the filter cover 16.

(12) In the cover 16, an outlet socket 18 for the purified fuel is arranged approximately centrally and is connected outside of the housing 12 with a fuel discharge line, not shown in FIG. 1. In the interior of the housing 12, the outlet socket 18 is connected with a discharge space 20 in an interior of the connecting socket 22. The connecting socket 22 extends on the side of the cover 16 facing the interior of the housing coaxially to a filter axis 24.

(13) In the normal mounted position under normal operating conditions of the internal combustion engine, the filter axis 24, as shown in FIG. 1, extends spatially in vertical direction. Axial, radial, coaxial, and circumferential relate in the following, if not indicated otherwise, to the filter axis 24.

(14) In radial direction outside of the connecting socket 22, the cover 16 has an inlet socket 26 for the fuel to be purified which is connected with an inlet space 28 in the housing 12. Outside of the housing 12, the inlet socket 26 is connected with a fuel supply line for the fuel that is not shown in FIG. 1.

(15) At the bottom of the filter bowl 14, a water outlet in the form of a water drainage socket 30 is arranged coaxial to the filter axis 24. The water drainage socket 30 is connected with a water collecting space 32 at the bottom in the housing 12. Outside of the housing 12, the water drainage socket 30 is connected with a water drainage line, not illustrated, by means of which the water separated from the fuel can be drained from the housing 12. In the water drainage socket 30 a water drain valve 34 with a water level sensor is arranged. In the rest state, the water drain valve 34 is closed so that no fluid can escape from the water collecting space 32 through the water drainage socket 30 from the housing 12. Upon reaching a predetermined maximum water level in the water collecting space 32, the water drain valve 34 opens automatically so that the separated water can drain through the water drainage socket 30.

(16) In the housing 12 an exchangeable filter element 36 is arranged. The filter element 36 is designed as a round filter element. The filter element 36 separates the inlet socket 26 seal-tightly from the outlet socket 18. The filter element 36 comprises a filter medium 38 which is folded in a star shape and which in particular filters particles out of the fuel to be purified. The filter medium 38 as a whole has the shape of a coaxial circular cylinder wall. On a lower end face which is facing the bottom of the filter bowl 14, the filter medium 38 is connected seal-tightly with a closure end disk 40. At its opposite end face which is facing the cover 16, the filter medium 38 is seal-tightly connected with a connecting end disk 42. A skeleton-like, fluid-permeable central tube 43 is extending between the connecting end disk 42 and the closure end disk 40 coaxially in an interior 45 of the filter medium 38 and connects the two end discs 40 and 42 to each other.

(17) The closure end disk 40 comprises a coaxial opening 44. The opening 44 is surrounded by the central tube 43. The opening 44 connects the interior 45 with the water collecting space 32. On the exterior side which is facing the bottom of the filter bowl 14, the closure end disk 40 comprises, for example, four support webs 46 which are distributed uniformly along an imaginary coaxial circular cylinder wall. It is also possible to provide more or fewer than four support webs 46. The imaginary circular cylinder wall surrounds the opening 44 and the water drainage socket 30. With the support webs 46 the filter element 36 is supported against the bottom of the filter bowl 14. Between the support webs 46 there are connecting openings 48 by means of which distribution of water in the water collecting space 32 in radial direction also external to the support webs 46 is possible.

(18) The connecting end disk 42 comprises a coaxial opening 50. The opening 50 is surrounded by two coaxial projections which are extending on the exterior side of the connecting end disk 42 in axial direction. The two projections delimit a receiving groove 52 for an annular insertion stay 54 of a separating unit 56 of the filter element 36.

(19) Between the radial inner circumferential side of the filter medium 38 and the central tube 43 there is a coaxial coalescing medium 58. The coalescing medium 58 is comprised of a layer of sponge cloth material. The coalescing medium 58 is closed circumferentially and extends between the connecting end disk 42 and the closure end disk 40. The coalescing medium 58 serves for combining even smallest water droplets contained in the fuel to larger water drops. As a result of its coalescing function and/or its water separating function, the filter element 36 can also be referred to as a coalescing element. Correspondingly, the fuel filter 10 can be referred to as a water separator device for fuel.

(20) The sponge cloth material is in particular a layered structure with a thickness in the dry state of approximately 0.4 cm to 2 cm. FIGS. 2 and 3 show schematic illustrations of the fabric material of the coalescing medium 58 viewed in the flow direction 78 of the fuel. FIG. 4 shows the sponge cloth material in a schematic illustration transverse to the flow direction 78. Here, the layer structure of the sponge cloth material can be seen.

(21) The sponge cloth material is produced according to a viscose method, for example, a cellulose xanthate method. For this purpose, wood is processed in reactors by means of solvents to viscose 59. Cotton is individualized as staple fiber with defined fiber lengths by tearing. The cotton fibers 60 can be seen in particular in FIG. 2. The proportion of viscose in the starting material for the sponge cloth material is approximately 70%, the proportion of cotton is approximately 30%.

(22) Subsequently, the initially flowable viscose 59 and the cotton fibers 60 are mixed and kneaded together with Glauber's salt and optionally a coloring agent. The incorporated Glauber's salt serves for pore formation. It determines the future pore size of the finished sponge cloth material.

(23) The kneaded mass is placed, for example, spread, by a machine, in particular by means of nozzles, onto a grid.

(24) Subsequently, the mass is dried on the grid and solidified. In the solidification process, the viscose can be regenerated. The viscose 59 and the cotton fibers 60 fuse to a unit. In this context, the initially flowable viscose 59 interlaces with the cotton fibers 60. The viscose 59 fuses so to speak between the cotton fibers 60 to larger contiguous areas in which crystals of Glauber's salt are embedded. The viscose 59 acts as a bonding material and connects the cotton fibers 60. The cotton fibers 60 act as a carrier material and contribute substantially to the strength of the finished sponge cloth material.

(25) The Glauber's salt is washed out subsequently. The dissolved crystals of the Glauber's salt are washed out. The washed-out mass is dried. The finished sponge cloth material has the corresponding pores 61.

(26) In FIG. 5, a coalescing material known in the prior art comprised of a nonwoven material of cotton, viscose, and polyester fibers (PES) is illustrated for differentiation. It can be seen clearly that the fibers therein, in contrast to the invention, are not connected by means of a bonding material.

(27) The separating unit 56 comprises a support basket 62 with a connecting section 64 which comprises also the insertion stay 54 and a separating medium 66.

(28) The connecting section 64 is approximately disk-shaped with a coaxial opening into which the connecting socket 22 of the cover 16 projects. On its exterior side which is facing the cover 16, the connecting section 64 comprises a coaxial connector socket 68. The connector socket 68 is bent at its free end face by 90 in radial direction inwardly. On the radial inner rim of the connector socket 68 a profiled ring seal 70 is seated. The connecting socket 22 is inserted into the connector socket 68 such that the connection is sealed by the profiled ring seal 70.

(29) The separation unit 56 is axially inserted, with the separating medium 66 leading, through the opening 50 of the connecting end disk 42. The support basket 62 and the separating medium 66 are located in the interior which is delimited by the coalescing medium 58, i.e., also in the interior 45 of the filter medium 38.

(30) The separation medium 66 is comprised of a hydrophobic screen fabric. It has the shape of a tube coaxial to the filter axis 24. It extends from the connecting end disk 42 to the closure end disk 40. The separation medium 66 is circumferentially closed.

(31) The circumferential wall of the support basket 62 has a grid-like structure and is liquid-permeable. On its end face which is correlated with the connecting socket 22, the support basket 62 is open. The lower end face of the support basket 62 which is facing the water collecting space 32 is closed. The separation medium 66 contacts the circumferential side of the support basket 62.

(32) Between the separation medium 66 and the coalescing medium 58, a precipitation gap 74 is provided in the interior 45. The precipitation gap 74 has the shape of an annular space. The precipitation gap 74 is delimited in radial outward direction by the coalescing medium 58 and in radial inward direction by the separating medium 66.

(33) On the radial outer circumferential side of the closure end disk 40 there is also an annular seal 72 arranged which supports in radial outward direction against the radial inner circumferential side of the filter bowl 14. The annular seal 72 seals the inlet space 28 relative to the water collecting space 32.

(34) In operation of the fuel filter 10, fuel that contains an additive and is to be purified and that may be contaminated with water and dirt particles is supplied from the fuel supply line, indicated by arrow 76, through the inlet socket 26 to the inlet space 28.

(35) The fuel flows through the filter medium 38, indicated by arrows 78, from its radial outward raw side to its radial inward clean side. The particles are thereby removed from the fuel. The filter medium 38 forms a first stage of the all together three-stage fuel filter 10 for the purification/water separation.

(36) The fuel with the additive, the particles having been removed, flows at the clean side through the pores 61 of the coalescing medium 58 in the radial direction from the exterior to the interior. In this context, even smallest water droplets that are contained in the fuel are caught in the pores 61 of the coalescing medium 58 and combined to greater water drops. The coalescing medium 58 forms a second stage for the purification/water separation. When the drop size is sufficient, the large water drops are again entrained by the fuel that is flowing through.

(37) The fuel with the additive and the large water drops flow through the openings of the central tube 43 and reach the precipitation gap 74.

(38) The fuel with the additive flows through the separation medium 66, which forms a third stage for the purification/water separation, in radial direction from the exterior to the interior, indicated by arrows 80, and flows in upward direction into the discharge space 20. The fuel with the additive that has been purified and from which the water has been removed exits the discharge space 20 through the outlet socket 18, indicated by arrows 82, and is supplied to the fuel discharge line.

(39) The large water drops on the other hand are retained by the separation medium 66. Due to their greater specific weight compared to the fuel, they sink down in the precipitation gap 74, indicated by arrows 84, into the water collecting space 32.

(40) As soon as the water level sensor of the water drain valve 34 indicates that a predetermined maximum water level has been reached, the water drain valve 34 is automatically opened. The water exits from the water collecting space 32 through the water discharge socket 30 and flows into the water drainage line.

(41) For servicing purposes, for example, for exchange of or for cleaning the filter element 36, the cover 16 is removed in axial direction from the filter bowl 14. The filter element 36 is then pulled out in axial direction from the filter bowl 14.

(42) For installation, the filter element 36 with the closure end disk 40 leading is inserted in axial direction into the filter bowl 14. Subsequently, the cover 16 with the connecting socket 22 leading is pushed in axial direction onto the open side of the filter bowl 14 so that the connecting socket 22 projects seal-tightly into the profiled ring seal 70.

(43) While specific embodiments of the invention have been shown and described in detail to illustrate the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.