Abstract
A capacitive level gauge for a container of a medium like compressed gas or liquid, comprising a body configured for being mounted on the container; two parallel lamellar electrodes extending from the body, for being inside the container and in contact with the medium; wherein the capacitive level gauge further comprises at least one spacer with two slots engaging with the two electrodes, respectively, maintaining a constant distance between the electrodes.
Claims
1.-11. (canceled)
12. A capacitive level gauge for a container of a medium said gauge comprising: a body configured for being mounted on the container; two parallel lamellar electrodes extending from the body, the electrodes disposable inside the container and in contact with the medium; at least one spacer with two slots engaging with the two electrodes and maintaining a constant distance between the electrodes; wherein the at least one spacer elastically deforms the electrodes so as to generate frictional forces holding the spacer in place without further fixation means.
13. The gauge according to claim 12, wherein the at least one spacer is made of plastic.
14. The gauge according to claim 12, wherein the at least one spacer comprises a plurality of spacers distributed along the electrodes.
15. The gauge according to claim 12, wherein the at least one spacer is configured to be slid around and along the electrodes.
16. The gauge according to claim 12, wherein for the at least one spacer, the two slots are substantially parallel to each other.
17. The gauge according to claim 12, wherein the electrodes have a curved cross-sectional profile,
18. The gauge according to claim 17, wherein the cross-section profile is curved with a radius that is at least one of greater than 10 mm and lower than 20 mm.
19. The gauge according to claim 12, wherein for the at least one spacer, the two slots are substantially straight.
20. The gauge according to claim 12, wherein each of the slots comprises a main portion and end portions, the end portions having an average width that is less than an average width of the main portion
21. The gauge according to claim 20, wherein the main portion comprises a central sub-portion with a reduced width.
22. The gauge according to claim 12, wherein each of the slots comprises a straight neutral axis.
23. The gauge according to claim 12, wherein each of the slots is elongate and forms a closed contour.
24. A spacer for electrodes of a capacitive level gauge, said spacer comprising an element with areas configured for receiving and holding the electrodes, wherein the areas are slots configured for receiving lamellar electrodes; and wherein each of the slots comprises a main portion and end portions, the end portions having an average width that is less than an average width of the main portion.
25. The spacer according to claim 24, wherein each of the slots is elongate and forms a closed contour.
26. The spacer according to claim 24, wherein the main portion comprises a central sub-portion with a reduced width.
27. The spacer according to claim 24, wherein each of the slots comprises a straight neutral axis.
Description
DRAWINGS
[0043] FIG. 1 is a perspective view and a sectional view of a capacitive level gauge according to a first exemplary embodiment of the invention.
[0044] FIG. 2 is an enlarged view of the sectional view of the body of the gauge of FIG. 1, in accordance with various embodiments of the present invention.
[0045] FIG. 3 is a perspective view of the electrical contact of the electrodes on the body of the gauge of FIGS. 1 and 2, in accordance with various embodiments of the present invention.
[0046] FIG. 4 is a perspective view of the electrode holding element of the gauge of FIGS. 1 to 3, in accordance with various embodiments of the present invention.
[0047] FIG. 5 is a perspective view of the spacer of the electrodes of the gauge of FIGS. 1 and 2, in accordance with various embodiments of the present invention.
[0048] FIG. 6 is a perspective view of a capacitive gauge according to a second exemplary embodiment of the invention.
DETAILED DESCRIPTION
[0049] FIGS. 1 to 5 illustrate a capacitive level gauge according to a first exemplary embodiment of the invention.
[0050] FIG. 1 shows a perspective view and a corresponding sectional view of the gauge.
[0051] The level gauge 2 comprises a body 4 designed to be mounted on a wall of a container (not represented). The container can for instance be filled with compressed and liquefied gas like for example butane or propane. In this exemplary embodiment, a gasket 6 is provided on a ring-shaped surface of the body for contacting a corresponding surface on the wall of the container, so as to provide a gas tight contact between an inner side 4.1 and an outer side 4.2 of the body. For instance, the body 4 is provided with four holes receiving fastening screws configured for engaging corresponding female threads on the wall of the container. It is however understood that other configurations for fastening the body to the container and/or for providing a gas tight contact with the container can be considered, in particular according to the technical common knowledge in the field of pressurized containers.
[0052] As this is apparent in FIG. 1, the gauge 2 comprises a pair of electrodes 8 and 10. The electrodes 8 and 10 are lamellar and extend along a main direction parallel to each other. They are kept at a constant distance from each other by means of the spacers 12. The proximal ends of the electrodes 8 and 10 are attached to the body 4 by means of the holding element 14. The latter is made of electrically insulating material, e.g. plastic, and comprises two slots, each receiving one of the electrodes 8 and 10. The holding element 14 is attached to the body 4 on the inner side 4.1 thereof. A fastener 16, e.g., a screw, is inserted transversally through a hole in the holding element and corresponding holes in the electrodes 8 and 10, for securely fastening the electrodes to the element. The hole in the holding element 14, receiving the fastener 16, extends through the slots.
[0053] Both proximal ends of the electrodes 8 and 10 protrude from the slots of the holding element 14 towards the body 4. The first electrode 8 has an end lateral face in pressure contact with an electrical lead 18 protruding from the body 4 so as to achieve an electrical contact there between. Similarly, the second electrode has an end lateral face in pressure contact with a body portion 4.3 so as to achieve an electrical contact there between. The second electrode 10 is thereby grounded and the first electrode 8 electrically connected to the electrical lead 18.
[0054] As this is apparent in FIG. 1, in the present exemplary embodiment, the body 4 comprises a sleeve on the inner side 4.1 thereof, that forms a cavity 20 housing the electrical lead 18 and the body portion 4.3 contacting the second electrode 10. Also, the holding element 14 is snap-fitted into the cavity 20 by engaging with a recess formed in the inner wall of the sleeve 4.4.
[0055] Still with reference to FIG. 1, the body 4 forms on its outer side 4.2 a cavity 22 in which the electrical lead 18 also protrudes and is in contact with an electronic display 24 via the electrical contacts 26.
[0056] FIG. 2 is an enlarged view of the upper part of the sectional view of FIG. 1. Each of the first and second electrodes 8 and 10 shows a cross-section with an arcuate profile, i.e., with a concave side and a convex side opposed to the concave side. Both cross-sectional profiles are, in various instances, parallel, i.e., the convex side of the first electrode 8 is in front of the concave side of the second electrode 10. In the cavity 20, we can observe that this is the convex lateral end side 8.1 of the first electrode 8 that contacts the electrical lead 18. Similarly, this is also the convex end lateral side 10.1 of the second electrode 10 that contacts the body portion 4.3. The latter forms an arcuate wall with two end faces that contact the electrode 10. Since the cut-plane of FIG. 1 does not pass through any of these two end faces, the contact between the second electrode 10 and the body portion 4.3 is not visible in FIG. 2 but well in FIG. 3.
[0057] Still with reference to FIG. 2, we can observe that, in the cavity 22, the electrical lead 18 is connected, for instance by brazing, to a plate 28, for instance a printed circuit board or PCB, that is attached to the body by screwing and that shows a pin that engages with the connector 26. The electronic display 24 is mounted on a support 30 that is inserted into the cavity 22 by a movement along the longitudinal axis of the body 4.
[0058] The PCB 18 can comprise electronics that is configured for storing the calibration parameters independently from any electrical power source. An electric power source such as a battery can be stored in the support 30 for supplying power to the electronic display 24 and the PCB 18 via the connector 26. This is particularly convenient because when the battery is empty, the support 26 can be removed for replacing the battery without losing the calibration parameters on the PCB 18.
[0059] The electrical lead 18 extends through a sleeve 32 and is attached thereto in a gas tight fashion, e.g., with molten glass. The sleeve 32 engages with a bore in the body 4 in a gas tight fashion by means of a gasket, for instance an O-ring, and is secured to the body 4 by a nut 34 with an outer thread engaging with a corresponding inner thread in the bore. The nut 34 holds and presses the sleeve 32 against a shoulder portion of the bore, thereby providing a stable fixation of the electrical lead 18. The mounting of the electrical lead can be according to the teaching of patent application WO 2016/116355 A1.
[0060] Still with reference to FIG. 2, we can observe that an annular airgap is provided between the nut 34 and the electrical lead 18. A sleeve 36 of electrically insulating material is slid around the electrical lead 18 and inside the airgap so as to support the electrical lead 18 against the bending force resulting of the radial force of the contact with the first electrode 8, for instance the end lateral side thereof. As this is apparent in FIG. 2, the sleeve shows a cut-out on the portion thereof that protrudes out of the body 4 and on the side of the first electrode, in order to provide some free space allowing the electrode to contact the lead.
[0061] FIG. 3 is a perspective view of the contact between the electrodes 8 and 10 and the electrical lead 18 and the body portion 4.3. The holding element is not represented for a better view of the contacts. The holes 8.2 and 10.2 in the electrode that receive the fastener 16 through the holding element 14 (FIGS. 1 and 2) are however visible. The arcuate cross-sectional profiles of the electrodes 8 and 10 is also well visible. We can observe that the electrical lead 18 contacts the end lateral face 8.1, for instance the convex end lateral face, of the first electrode 8 at a central position thereof. We can also observe that the body portion 4.3 forms an arcuate wall with two end faces contacting the end lateral face 10.1, for instance the convex end lateral face of the second electrode 10, whereas only one of the two end faces is visible.
[0062] FIG. 4 is a perspective view of the holding element 14. It comprises a proximal front end 14.1 configured for engaging with the body and a distal end 14.2 holding the electrodes.
[0063] The proximal front end 14.1 comprises a circular wall 14.1.1 provided with a toothed outer profile 14.1.2 for engaging with the recess 4.5 in the sleeve 4.4 of the body (FIG. 2). A series of axial cut-outs 14.1.3 are provided along the wall 14.1.1 so as to form different sections thereof that can more easily bend during insertion of the proximal front end 14.1 into the cavity 20 of the body 4 (FIG. 2).
[0064] The distal end 14.2 features the slots 14.2.1 configured to receiving the electrodes. As this is apparent, the slots 14.2.1 show an arcuate profile that corresponds to the profile of the electrodes. The slots extend longitudinally along the whole length of the distal end 14.2 so that the electrodes, once inserted therein, extends through the distal end 14.2 and protrude therefrom in the proximal front end 14.1. The holding element 14 features also a transversal hole 14.2.2 that extends through the slots 14.2.1, designed for receiving the fastener 16 (FIGS. 1 and 2).
[0065] When assembling the gauge, the electrodes are inserted through the respective slots 14.2.1 and the fastener 16 (FIGS. 1 and 2) is inserted into the hole 14.2.2 and the corresponding holes 8.2 and 10.2 (FIG. 2) of the electrode so as to form a stable assembly. That assembly is then mounted on the body by an insertion movement along the longitudinal direction, until the distal end portion 14.1, more particularly the toothed profiles 14.1.2, snaps into the recess or groove 4.5 (FIG. 2). During that operation, the holding element 14 can be slightly tilted relative to the longitudinal direction of the body such as to facilitate insertion of the end portion of the electrodes relative to the electrical lead and the body portion. Once the end lateral faces of each electrode has started to pass by the electrical lead and the body portion, the holding element can be aligned with the longitudinal direction until each toothed profile 14.1.2 snaps into the corresponding groove or recess in the body.
[0066] FIG. 5 is a perspective view of the spacer 12. It is essentially made of a plate 12.1 with two slots 12.2. Each slot 12.2 is configured to achieve a resilient contact with the corresponding electrode once inserted there into. For instance, when the electrode shows a curved cross-sectional profile, as in the present exemplary embodiment, the slots 12.1 can show a generally straight profile or at least a less curved profile than the electrodes. More specifically, the slots 12.1 show at a main portion a width that is substantially larger than the wall thickness of the electrodes. The slots 12.1 can show ends portions 12.2.1 with a reduced thickness, i.e., of about the wall thickness of the electrodes. It can also show a central portion 12.2.2 also with a reduced thickness, however, in various instances, greater than the wall thickness of the electrodes.
[0067] The spacer 12 is advantageously made of plastic, e.g., thermoplastic, by injection moulding. The plate 12.1 can show a thickness greater than 2 mm and/or less than 8 mm. The slots 12.2 can have a length greater than 5 mm and/or less than 30 mm. Each slots 12.2 advantageously shows two opposes profiles that are symmetric with regard to a median plane. The distance between the neutral fibres or axes of two adjacent slots 12.2 of a spacer 12 can be greater than 5 mm and/or less than 20 mm. The plate 12.1 of the spacer 12 advantageously shows a rounded peripheral border.
[0068] FIG. 6 is a perspective view of a second embodiment of the invention. It shows a capacitive gauge, similarly constructed to the gauge of the first exemplary embodiment in FIGS. 1-5. The reference numbers of the first exemplary embodiment are used for designating the same or corresponding elements; these numbers being however incremented by 100. It is referred to the description of these elements in relation with the first exemplary embodiment. Specific numbers comprised between 100 and 200 are used for designating specific elements.
[0069] The gauge 102 of FIG. 6 differs from that the gauge of FIGS. 1 to 4, essentially in the body 104 which comprises a gas passage between the inner side 104.1 and the outer side 104.2, in connection with the gas outlet 138. A shut-off valve (not visible) is provided in the body 104 and operated by the hand-wheel 140. Such a gas passage, gas outlet and shut-off valve are as such well known to the skilled person and do not need to be further detailed.
[0070] Also the body 104 shows a tapered outer thread 105 for engaging in a gas tight fashion a collar of a container. This tapered outer thread 105 replaces the gasket and the holes receiving the fastening screws visible in FIG. 1 of the first exemplary embodiment.
