CONNECTION HEAD WITH A RETURN CAVITY

Abstract

A connection head for being arranged in an orifice of a fluid tank with a return cavity in the form of a radial duct is provided. The return cavity overcomes the problems of the formation of air bubbles in the tank and enhances the functioning of the sensor in the tank.

Claims

1. A Connection head for being arranged in an orifice of a fluid tank, the connection head comprising: an electrically insulating base, wherein the base is provided with at least a first opening for receiving a tube; and a return cavity integrated in the connection head.

2. The connection head according to claim 1, wherein the base of the connection head is extruded to form a radial duct terminating at the return cavity.

3. The connection head according to claim 2, wherein the radial duct is slanted along an axial direction.

4. The connection head according to claim 1, wherein the tube is electrically conductive.

5. The connection head according to claim 1, wherein the return cavity terminates at an opening on a peripheral surface of the connection head

6. The connection head according to claim 1, wherein the tube comprises a first electrically conductive tube, and wherein the connection head further comprises at least a first electrically conductive grounding element with at least a first receptacle, wherein the first electrically conductive grounding element is arranged such that the first electrically conductive tube is electrically connected to the first grounding element.

7. The connection head according to claim 6, wherein the first receptacle of the first electrically conductive grounding element is aligned with a first opening of the base to encompass the first electrically conductive tube.

8. The connection head according to claim 6, wherein the first electrically conductive grounding element comprises a metal plate.

9. The connection head according to claim 8, wherein the metal plate is fixed to the base by at least one screw.

10. The connection head according to claim 1, wherein the base further comprises an electrical connector for electrically contacting at least one fluid sensor assembly.

11. A fluid sensor comprising the connection head according to claim 1, further comprising at least one fluid quality sensor unit which is distanced apart from the connection head for being arranged inside the fluid tank.

12. The fluid sensor according to claim 11, further comprising a fluid level sensor.

13. A selective catalytic reduction (SCR) system for purification of harmful NOx components in the exhaust gases of diesel vehicles with a urea tank and a fluid sensor according to claim 11 installed in the urea tank for measuring one or several properties of a urea solution in the tank.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0051] FIG. 1 shows a cross-sectional view of a connection head according to an embodiment of the present invention;

[0052] FIG. 2 shows a perspective view of a connection head according to an embodiment of the present invention;

[0053] FIG. 3 shows a bottom view of the connection head according to FIG. 1,

[0054] FIG. 4 shows a schematic perspective representation of a detail of the connection head according to an embodiment of the present invention;

[0055] FIG. 5 shows a top view of the connection head according to the embodiment of FIG. 4;

[0056] FIG. 6A shows another sectional view of the connection head according to FIG. 5;

[0057] FIG. 6B shows another top view of the connection head according to FIG. 5;

[0058] FIG. 7 shows an enlarged cross-sectional view of the connection head according to FIG. 5;

[0059] FIG. 8 shows another sectional view of the connection head according to FIG. 7;

[0060] FIG. 9 shows a zoomed view of the connection head with a return cavity according to FIG. 7; and

[0061] FIG. 10 shows a perspective view of a fluid sensor according to an embodiment of the present invention.

DETAILED DESCRIPTION

[0062] In the following, the Figures are described in detail, first referring to FIG. 1. FIG. 1 shows a perspective view of a connection head 100 of a urea sensor according to the present invention. The urea sensor is part of an SCR system, and can be mounted at an orifice in the wall of a urea tank (not shown in the figure).

[0063] The connection head 100 which is attached to the urea tank and a sensor unit (not shown in the figure), which is arranged distanced apart from the connection head 100 and extends into the tank. The sensor unit comprises a module for measuring fluid properties like temperature, urea concentration and fluid quality.

[0064] According to an embodiment of the present invention, a return cavity 108 is integrated in the connection head 100, which feeds back unused urea solution into the tank. A suction tube 110 allows for retrieving the urea solution out of the tank. Furthermore, a heating coil 112 is provided for heating the urea solution in the vicinity of the sensor unit 106, and the suction tube 110 in order to avoid freezing of, or thaw of already frozen urea solution. The suction tube 110 for sucking fluid out of the tank 102 is fixed to the heating coil 112 via grounding elements 128, in order to warrant that the fluid which is sucked out has the right temperature for operation. Of course, the clamps may also be fabricated from a plastic material. The return cavity 108 according to this embodiment is configured in the form of a duct arranged in the connection head. It is to be noted that the return cavity 108 according to this invention is not limited to a duct-shaped form. Alternative variations of the return cavity are envisaged in other embodiments of the present invention.

[0065] A support tube 114 accommodates a series of reed relays (not visible in the figures) and allows a float (not shown in the figure) to slide along the direction 118. The float comprises a magnetic element so that the reed relays are actuated by the movement of the float along the support tube 114, thereby providing a signal indicative of the level of the urea solution in the tank.

[0066] The connection head 100 comprises a base 120, which is fabricated from an electrically insulating material. The base 120 is mounted at the urea tank by means of bulges 122 on its peripheral rim, wherein the bulges 122 are configured to fit with corresponding notches (not shown in the Figures) in the opening of the tank, ensuring the correct azimuthal orientation of the connection head 100 once it resides in the opening of the tank. The support tube 114 is mechanically stabilized and fixed to the base 120.

[0067] FIG. 2 shows a detailed cross-sectional side view of the connection head 100 according to the above embodiment as depicted in FIG. 1. As can be seen from this drawing, the return cavity 108 has essentially a shape of a radial duct at an opening on a curved surface of the connection head 100. As will be apparent in more detail from FIG. 3, the return cavity 108 is formed by extruding the base of the connection head as can been seen from a detailed view of the base of the connection head. Extruding the base 120 is not the only method of forming the return cavity 108. It may also be formed by the pressing the base 120 or attaching an external component to the base 120. Moreover, as can be seen from FIG. 3 the base 120 is closed from a side facing the urea tank 102 by means of a lid 134 that is attached to the base 120 by means of a plurality of resilient latches 136, which interact with corresponding locking protrusions 138.

[0068] FIGS. 4 and 5 show perspective views of a connection head 200, wherein an inner structure of the connection head is presented. Only differences to the previous embodiment as shown in FIGS. 1 to 3 is described in the following. Otherwise, full reference is made to the preceding text.

[0069] The return cavity according to this embodiment is presented in the form of a direct opening in the connection head.

[0070] FIGS. 6A and 6B show the connection head 200 of FIGS. 4 and 5 from the top. A venting element 246 (as shown in FIG. 6B) is provided for pressure equalization. The respective tubes are electrically conductive and are connected to a first and a second grounding element 252, 254, respectively. Each of the grounding elements 252, 254 is attached to the base 220 by means of a plurality of screws 256. According to the embodiment shown in FIG. 6B, each of the grounding elements are attached with three screws 256. However, it is clear that also only two screws or four or more screws could be used for fixing the grounding elements 252, 254. Because the first and second grounding elements 252 and 254 do not completely surround the respective tubes, but form a partly open receptacle, there is sufficient resiliency for allowing a snap-fit mounting of the tubes.

[0071] FIG. 7 shows a zoomed view of the connection head 200 according to the embodiment where the return cavity 208 is a direct opening in the connection head, and also shows the suction tube 210.

[0072] FIGS. 8 and 9 show a detail of the connection head 200 without showing the insulating tubes. In this open representation, it is visible that the return cavity is completely different in design and functionality compared to the suction tube. According to the present invention, the first and second grounding leads 158 are over molded by the electrically insulating material of the base 120, and are only laid open in the contact regions for the screws 156 and 160.

[0073] FIG. 10 shows a perspective view of a urea sensor 300 according to the present invention. The urea sensor is part of an SCR system and can be mounted at an orifice in the wall of a urea tank 302. The urea sensor 300 comprises a connection head 304 which is attached to the urea tank 302 and a sensor unit 306 which is arranged distanced apart from the connection head 304 and extends into the tank 302. The connection head 304 may be formed according to one of the embodiments explained above with reference to FIGS. 1 to 9.

[0074] The sensor unit 306 comprises a module for measuring fluid properties like temperature and urea concentration and fluid quality.

[0075] A return cavity (not visible in this drawing) formed in the connection head 304 feeds back unused urea solution into the tank 302. A suction tube 310 allows retrieving urea solution out of the tank 302. Furthermore, a heating coil 312 is provided for heating the urea solution in the vicinity of the sensor unit 306 and the suction tube 310 in order to avoid freezing of or thaw already frozen urea solution. The suction tube 310 for sucking fluid out of the tank 302 is fixed to the heating coil 312 via grounding elements 328, in order to warrant that the fluid which is sucked out has the right temperature for operation. Of course, the clamps 328 may also be fabricated from a plastic material.

[0076] A support tube 314 accommodates a series of reed relays (not visible in the figures) and allows a float 316 to slide along the direction 318. The float 316 comprises a magnetic element so that the reed relays are actuated by the movement of the float 316 along the support tube 314, thereby providing a signal indicative of the level of the urea solution in the tank 302.

[0077] The connection head 304 comprises a base 320 which is fabricated from an electrically insulating material. The base 320 is mounted at the urea tank 302 by means of bulges 322 on its peripheral rim, the bulges 322 fitting to corresponding notches (not shown in the Figures) in the opening of the tank 302, ensuring the correct azimuthal orientation of the connection head 304 once it resides in the opening of the tank 302.

[0078] On top of the base 320, a cover 324 is provided for protecting a power line, a grounding line, and a CAN bus. An electrical connector (not shown in the drawings) which is attached to the wiring system of the vehicle, for instance a truck, can be connected to the cover. Next to the cover 324, the protective plugs 326 for the protection of the tube openings against dirt can be seen. These protective plugs 326 are removed before the tubing from the vehicle is attached.

[0079] The support tube 314 is mechanically stabilized and fixed to the base 320 by means of a float stop 330.

[0080] It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present invention.

[0081] Spatially relative terms, such as proximal, distal, lower, above, upper and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as below or beneath other elements or features would then be oriented above the other elements or features. Thus, the exemplary term below can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 or at other orientations), and the spatially relative descriptors used herein interpreted accordingly.

[0082] As used herein, the singular forms a, an and the are intended to include the plural forms as well, unless expressly stated otherwise. It will be further understood that the terms includes, comprises, including and/or comprising, when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It will be understood that when an element is referred to as being connected or coupled to another element, it can be directly connected or coupled to the other element or intervening elements may be present. As used herein, the term and/or includes any and all combinations of one or more of the associated listed items.

[0083] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0084] It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-described embodiments (and/or aspects thereof) may be used in combination with each other. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. Dimensions, types of materials, orientations of the various components, and the number and positions of the various components described herein are intended to define parameters of certain embodiments, and are by no means limiting and are merely example embodiments. Many other embodiments and modifications within the spirit and scope of the claims will be apparent to those of ordinary skill in the art upon reviewing the above description. The scope of the invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. In the appended claims, the terms including and in which are used as the plain-English equivalents of the respective terms comprising and wherein. Moreover, in the following claims, the terms first, second, and third, etc. are used merely as labels, and are not intended to impose numerical requirements on their objects.

[0085] While the present disclosure has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the intent of the disclosure as defined by the appended claims. The exemplary embodiments should be considered in a descriptive sense only, and not for purposes of limitation. Therefore, the scope of the present disclosure is defined not by the above description of the invention, but by the appended claims, and all differences within the scope will be construed as being included in the present invention.

REFERENCE NUMERALS

[0086]

TABLE-US-00001 Reference Numeral Description 100, 200 Connection head 102 tank 108 Return cavity, radial duct 110 Suction tube 112 Heating coil 114 Support tube 118 Sliding direction of float 120 Base 122 Bulge 134 Lid 136 Resilient latch 138 Locking protrusion 146 Venting element 148 Inlet of heating fluid 150 Outlet of heating fluid 252 First grounding element 254 Second grounding element 256 Fixing screw 258 First and second grounding lead 160 Grounding screw 300 Urea sensor 302 Tank 304 Connection head 306 Sensor unit 310 Suction tube 312 Heating coil 314 Support tube 316 Float 318 Sliding direction 320 Base 322 Bulges 324 Cover 326 Protective plug 328 Clamp 330 Float stop