Water separator with a water overlfow secured by means of a float valve

Abstract

A water separator for water contained in fuel has a water separator housing with a separator element. A water collecting chamber is arranged in operation of the water separator below the separator element. A water collecting chamber through opening fluidically connects the water collecting chamber with the separator element. A drainage through opening has a first end which leads, for draining water from the water separator, out of the water separator. A second end is connected fluidically by an overflow valve to the water collecting chamber. The overflow valve has a float closing off a connection between drainage through opening and water collecting chamber when a water filling level has not reached the overflow valve. The float has an average density of 700 kg/m.sup.3 to 1,000 kg/m.sup.3 so that the float, when the water filling level is reached, opens the connection between water collecting chamber and drainage through opening.

Claims

1. A water separator for water contained in fuel, the water separator comprising: a water separator housing; a separator element arranged in the water separator housing; a water collecting chamber arranged in operation of the water separator below the separator element; a water collecting chamber through opening fluidically connecting the water collecting chamber with the separator element; a drainage through opening comprising a first end which leads, for draining water from the water separator, out of the water separator and further comprising a second end connected fluidically by an overflow valve to the water collecting chamber; the overflow valve comprising a float closing off a connection between the drainage through opening and the water collecting chamber when a water filling level has not reached the overflow valve; the float having an average density that amounts to more than 700 kg/m.sup.3 and less than 1,000 kg/m.sup.3 so that the float, when the water filling level has reached the overflow valve, opens the connection between the water collecting chamber and the drainage through opening.

2. The water separator according to claim 1, wherein the average density of the float amounts to more than 819 kg/m.sup.3.

3. The water separator according to claim 1, wherein the overflow valve comprises a valve seat with a sealing surface, wherein a geometry of the sealing surface at least partially is complementary to an exterior side of the float.

4. The water separator according to claim 3, wherein the valve seat is embodied in the water separator housing.

5. The water separator according to claim 3, wherein the overflow valve comprises an insert member, wherein the valve seat is embodied on the insert member, wherein the insert member is connected to the water separator housing.

6. The water separator according to claim 5, wherein the drainage through opening is formed at least partially in the insert member.

7. The water separator according to claim 1, wherein the water collecting chamber through opening between the water collecting chamber arid the float comprises a cross-sectional surface area of less than 7 mm.sup.2, a baffle, or a labyrinth.

8. The water separator according to claim 1, wherein the water collecting chamber through opening between the water collecting chamber and the float comprises a combination of two or more of the elements selected from the group consisting of a cross-sectional surface area of less than 7 mm.sup.2, a baffle, and a labyrinth.

9. The water separator according to claim 1, further comprising a water discharge device for at least partial drainage of water collected in the water collecting chamber.

10. The water separator according to claim 1, wherein the water separator comprises a fuel tank and a return line fluidically connected with the fuel tank, wherein the drainage through opening is fluidically connected with the return line.

11. The water separator according to claim 1, wherein the separator element comprises a screen pipe and a support pipe, wherein between the screen pipe and the support pipe a water separating gap is formed, and wherein the water separating gap is fluidically connected with the water collecting chamber.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Further features and advantages of the invention can be taken from the following detailed description of several embodiments of the invention, from the figures of the drawing showing details important to the invention, as well as from the claims.

[0043] The features illustrated in the drawing are illustrated such that the particularities according to the invention can be made visible clearly. The various features can be realized individually by themselves or several of them in any combination in variants of the invention.

[0044] FIG. 1 is a section view of a first embodiment of a water separator with a water separator housing and an overflow valve, wherein a valve seat of the overflow valve is formed in the water separator housing.

[0045] FIG. 2 is a section view of a second embodiment of a water separator with an overflow valve, wherein a valve seat of the overflow valve is formed in an insert member.

[0046] FIG. 3 is an enlarged illustration of the overflow valve of FIG. 2.

[0047] FIG. 4 is a section view of a third embodiment of a water separator with an overflow valve, wherein a valve seat of the overflow valve is formed in an insert member and a water collecting chamber through opening is extending adjacent to the overflow valve.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0048] FIG. 1 shows a water separator 10 in the form of a fuel filter. The water separator 10 comprises a separator element 12. The separator element 12 is arranged in a water separator housing 14.

[0049] The separator element 12 is in the form of a filter element, more precisely in the form of a round filter element. In this context, the separator element 12 is embodied substantially with axial symmetry to its central filter element longitudinal axis 16. The separator element 12 comprises a filter medium 18 for separating dirt from the fuel. The filter medium 18 has arranged fluidically downstream thereof a coalescing medium 20. On the coalescing medium 20, water droplets of the water contained in and to be separated from the fuel ale formed. The coalescing medium 20 is supported radially, i.e., perpendicular to the central filter element longitudinal axis 16, on a support pipe 22. Radially inwardly displaced relative to the support pipe 22, the separator element 12 has a screen pipe 24. Between support pipe 22 and screen pipe 24, there is a water separating gap 26.

[0050] The water separated at the separator element 12 flows through the water separating gap 26 farther through a water collecting chamber through opening 28 into a water collecting chamber 30. The water separated from the fuel collects thus in the water collecting chamber 30. Reaching a predefined filling level of water in the water collecting chamber 30 is detectable by water level electrodes (not shown) of the water separator 10. Detection of reaching the predefined filling level of the water collecting chamber 30 triggers a service message. The water separated from the fuel can then be drained in a shop by means of a water discharge device (not shown) in the bottom area 32 of the water collecting chamber 30. The water discharge device is in this context preferably in the form of a stopper, a tap, or a valve.

[0051] When the water collecting chamber 30 is not emptied, in most known water separators damage of the water separator is caused by a water level that continues to rise. In this context, freezing of water in the water separator may occur and/or water may “break through” into an injection system causing corrosion effects in the injection system. Alternatively, the ignored service signal can be associated with shutting down the combustion engine operated with the fuel.

[0052] In contrast to this, the water separator according to the invention can continue to operate safely even in case of an ignored service signal. For this purpose, the water separator 10 comprises a drainage through opening 34. In the drainage through opening 34 a throttle 36 is arranged in order to regulate the drainage quantity. The throttle 36 is designed in the form of a press-fit throttle. The drainage through opening 34 is connected fluidically with one end with a fuel tank (not shown) and with the other end with an overflow valve 38.

[0053] The overflow valve 38 is arranged in an annular channel 40 of the water separator housing 14. The annular channel 40 at the bottom side is embodied to be at least partially closed by a ceiling 42 of the water collecting chamber 30.

[0054] The overflow valve 38 is illustrated only schematically in FIG. 1. It comprises a float 44. The float 44 is spherical. In FIG. 1, the float 44 is shown in an upper position (it is identified in FIG. 1 by reference character 44) and in a lower position. The lower position of the float 44 corresponds to the position of the float 44 “in usual operation”, i.e., without overfull water collecting chamber 30. The float 44 is seated in this state in a valve seat 46 of the overflow valve 38 and seals the drainage through opening 34 relative to the water collecting chamber through opening 28.

[0055] The float 44 has an average density between 700 kg/m.sup.3 and 800 kg/m.sup.3. The float 44 is therefore lighter than water and heavier than diesel fuel. The float 44 therefore does not rise in diesel fuel, while it will rise with increasing water level and open the fluidic connection of the overflow valve 38 between the water collecting chamber through opening 28 and the drainage through opening 34 so that the water can drain via the drainage through opening 34. As a result, through the drainage through opening 34 no fuel flows out of the water separator 10 back into the fuel tank.

[0056] FIG. 2 shows a part of a further water separator 10. The water separator 10 comprises an overflow valve 38 that is arranged fluidically between a water collecting chamber through opening 28 and a water collecting chamber 30. The overflow valve 38 is connected furthermore with a drainage through opening 34. The overflow valve 38 is fastened in the ceiling 42 of the water collecting chamber 30. A float 44 of the overflow valve 38 is positioned above the ceiling 42 in the operating state of the water separator 10.

[0057] FIG. 3 shows a greatly enlarged illustration of the water separator 10 of FIG. 2. FIG. 3 illustrates that the overflow valve 38 is designed in a constructively particularly simple configuration in that it has an insert member 48 in which a valve seat 46 with a sealing surface 50 for the float 44 is formed. The valve seat 46 therefore, in contrast to the embodiment of the water separator 10 according to FIG. 1, must not be embodied within the water separator housing 14. The insert member 48 is fastened by a first thread connection 52 and a second thread connection 54 to the water separator housing 14. Alternatively or additionally, the insert member 48 can be fastened by radial pressing grooves (not shown) in the water separator housing 14.

[0058] The insert member 48 comprises in the direction of its central longitudinal axis 56 a first through opening 58 which with one end is fluidically connected with the water collecting chamber through opening 28 and with the other end with the water collecting chamber 30. In the insert member 48, transverse to the direction of its longitudinal axis 56, in particular perpendicular to the direction of its longitudinal axis 56, a drainage through opening 34 is formed. According to FIG. 3, the drainage through opening 34 is closed off by the float 44. Rising of the float 44 in backed-up water effects however a fluidic connection between the first through opening 58 and the drainage through opening 34 so that water can drain from the water collecting chamber 30 (see FIG. 2).

[0059] FIG. 4 shows a further water separator 10. The water separator 10 according to FIG. 4 corresponds to the water separator 10 according to FIG. 2. An arrow 60 indicates the path of the water separated by the separator element 12 into a water collecting chamber 30.

[0060] In contrast to the water separator 10 according to FIG. 2, a water collecting chamber through opening 28 does not extend through the overflow valve 38 but bypasses the overflow valve 38. Fuel which is backing up in the water collecting chamber 30 can therefore be displaced through the water collecting chamber through opening 28 upwardly to the separator element 12, wherein the indication “upward” is relative to the operating state of the water separator 10. On the other hand, water that is backing up in the water collecting chamber 30 is guided via drainage through opening 34 into a return line 62 which extends into a fuel tank (not shown).

[0061] In summarizing the above, the invention concerns a water separator, in particular in the form of a fuel filter for a motor vehicle. The water separator comprises a water collecting chamber. The water collecting chamber is closed off by an overflow valve relative to a drainage through opening. The overflow valve comprises a float that is lighter than water but heavier than fuel, in particular heavier than diesel fuel. The float rises as water is backing up in the water collecting chamber and opens the drainage through opening that is fluidically connected with the overflow valve and through which the backed-up water can drain. Fuel on the other hand does not open the overflow valve so that a drainage via the drainage through opening out of the water separator is realized only in case of water backing up so that the efficiency of the water separator is greatly improved. The drainage through opening is preferably fluidically connected with a fuel tank of the motor vehicle. For regular water discharge from the water collecting chamber, the latter is preferably connected with a water discharge device.

[0062] 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.