Radar level gauge with a sealed dielectric filling member and a structural reinforcement element

Abstract

The present invention provides a radar level gauge having a sealed dielectric filling member and a structural reinforcement element. The radar level gauge includes a signal propagation device, a dielectric filling member disposed in the signal propagation device, and a sealing device for preventing the contents of the tank from escaping into the external environment. Wherein, the dielectric filling member includes a main body and a sealing device, and the sealing device includes a first sealing portion. The radar level gauge further includes a structural reinforcement element positioned above the first sealing portion.

Description

Technical Field

[0001] The present disclosure relates to a radar level gauge having a dielectric filling member disposed in an antenna device of the radar level gauge, wherein the dielectric filling member includes a sealing device including a first sealing portion and a second sealing portion. The radar level gauge further includes a structural reinforcement element disposed between the first sealing portion and the second sealing portion. Background Art

[0002] Radar level gauges (RLGs) are commonly used to measure the filling level of products such as process fluids, particulate mixtures, and other materials contained in tanks. An RLG can include, for example, a transceiver, an antenna device, and a processing circuit adapted to determine the filling level based on the relationship between microwaves transmitted and received by the transceiver.

[0003] An RLG can also include a so-called dielectric filling member positioned within a cavity of the antenna device. The dielectric filling member is provided to protect the antenna device from heat and chemicals within the tank. The dielectric filling member also serves the purpose of a process seal for preventing the release of tank contents to the external surrounding environment. The process seal is typically provided between a portion of the tank and a portion of the antenna device.

[0004] However, the dielectric filling member can be exposed to a relatively high negative pressure within the tank. This can cause the dielectric filling member to be pressed towards the tank. Accordingly, there is a desire to improve the dielectric filling member to improve its resistance to such negative pressure. Summary of the Invention

[0005] The object of the present disclosure is to describe a radar level gauge having improved strength to withstand a relatively high negative pressure that can be obtained in a tank.

[0006] According to a first aspect, this object and other objects are achieved by a radar level gauge for determining a process variable of a product in a tank by using an electromagnetic measurement signal. The radar level gauge includes an antenna device. The antenna device includes an antenna mounting structure. The antenna device is adapted to direct a microwave transmission signal towards the product and to return the reflection of the microwave transmission signal from the surface of the product. A dielectric filling member is provided in the antenna device. The dielectric filling member includes a body and a sealing device for preventing the contents of the tank from escaping into the external environment. The sealing device is provided around the periphery of the body and includes a first sealing portion positioned between a part of the antenna mounting structure and a part of the tank. The lower surface of the first sealing portion is arranged to abut against the said part of the tank. And a structural strengthening element is provided around the periphery of the body. The structural strengthening element is arranged to abut against the upper surface of the first sealing portion such that when viewed in the direction of the microwave transmission signal, the first sealing portion is positioned above the said part of the tank and below the structural strengthening element.

[0007] The dielectric filling member is intended to represent a seal for protecting the antenna device from the thermal and chemical shock effects of the contents in the tank. Thus, the dielectric filling member should be formed of a dielectric filling material that is waterproof and resistant to the chemicals provided in the tank. The dielectric filling material should also preferably not interfere with the operation of the RLG. By way of non-limiting example, the dielectric filling material can be formed of PTFE (polytetrafluoroethylene). Other alternatives such as PFA (perfluoroalkoxy alkane) and FEP (fluorinated ethylene propylene) can also be contemplated. With regard to PTFE, the material can withstand relatively high temperatures, i.e., above 150 °C, which is preferred.

[0008] Furthermore, the structural strengthening element should be understood to be an element formed of a material having a greater resistance to deformation than the material of the dielectric filling member. According to an exemplary embodiment, the structural strengthening element can be formed of a material having a stiffness coefficient higher than that of the sealing device. The stiffness coefficient is here intended to refer to the so-called Young's modulus, which is a measure of the deformation of a material under specific loading conditions. According to an exemplary embodiment, the structural strengthening element can be formed of a metallic material. The metallic material can be, for example, steel.

[0009] Furthermore, the term "antenna mounting structure" is the structure for mounting the antenna device to the tank. The antenna mounting structure can form an integral part with the remaining antenna device, or the antenna mounting structure can be provided as a separate part that is connected to the antenna device in a suitable manner, such as, for example, screwed to the antenna device.

[0010] Advantages lie in that an improved seal is provided to prevent the contents of the tank from escaping into the external environment. Specifically, the structural reinforcement element will increase the stiffness at the interconnecting portion between the antenna mounting structure and the tank of the sealing device. Thereby, the dielectric filling member is less sensitive to the negative pressure from the tank because the structural reinforcement element will prevent the dielectric filling member from being pressed towards the interior of the tank. The use of the structural reinforcement element is particularly advantageous during relatively high temperatures when the materials in the sealing device tend to undergo undesired elastic deformation. Thereby, the structural reinforcement element will prevent the dielectric filling member from deforming towards the tank. This will in turn improve the measurement quality of the RLG because it can be ensured that the dielectric filling member is kept in the correct position in the antenna device.

[0011] According to an exemplary embodiment, the sealing device may be integrally formed with the body. The sealing device and the body can thus be formed as one piece and have the same material.

[0012] According to an exemplary embodiment, the sealing device may further include a second sealing portion, the second seal including an upper surface and a lower surface, the upper surface being arranged to abut against the said portion of the antenna mounting structure, and the lower surface being arranged to abut against the structural reinforcement element.

[0013] Preferably, the structural reinforcement element is located here between the first sealing portion and the second sealing portion such that when viewed in the direction of the microwave transmission signal, the first sealing portion is located below the structural reinforcement element and the second sealing portion is located above the structural reinforcement element. The advantage is that an improved seal with respect to the antenna mounting structure can be achieved.

[0014] According to an exemplary embodiment, the body may have a generally conical portion, and the first sealing portion and the second sealing portion are each arranged as respective annular flanges radially extending from the base portion of the conical portion.

[0015] Furthermore, and according to an exemplary embodiment, the structural reinforcement element may be sandwiched between the first sealing portion and the second sealing portion.

[0016] According to an exemplary embodiment, the sealing device may include a circumferentially arranged cavity portion, the circumferentially arranged cavity portion being formed by sintering the outer end portion of the second sealing portion to the first sealing portion, and the structural reinforcement element being arranged in the circumferentially arranged cavity portion.

[0017] Thereby, the structural reinforcement element is encapsulated within the circumferentially arranged cavity portion.

[0018] According to an exemplary embodiment, the structural reinforcement element may include a plurality of through holes extending in the direction between the first sealing portion and the second sealing portion, and the first sealing portion and the second sealing portion are connected to each other at the plurality of through holes by sintering the first sealing portion and the second sealing portion to each other.

[0019] Thus, the structural reinforcement element will be well integrally formed between the first sealing part and the second sealing part.

[0020] The term sintering should be understood to mean a process in which two elements, namely the first sealing part and the second sealing part, are integrally formed by pressing them against each other and heating them without melting them.

[0021] According to an exemplary embodiment, the structural reinforcement element may include a first element part and a second element part connected to each other around a body.

[0022] Advantageously, the structural reinforcement element is relatively easy to assemble to the sealing device. According to an exemplary embodiment, the first element part and the second element part may be formed in a semi-circular shape.

[0023] The first element part and the second element part are preferably attached to each other, and according to an exemplary embodiment, the first element part may thus preferably include a protrusion, and the second element part may include a notch, wherein the protrusion connects to the notch when the structural reinforcement element is connected around the body. Using the protrusion and the notch will enable a so-called snap-fit connection between the first element part and the second element part, which will attach the two parts to each other when set in the "correct" position. Thus, no additional connecting elements are required.

[0024] According to an exemplary embodiment, when viewed in the direction of the microwave transmission signal, the structural reinforcement element may include at least two layers of reinforcement elements.

[0025] Thus, each layer may be formed of a relatively thin sheet of material. Additionally, the layers may be arranged to overlap at the joint between the two aforementioned semi-circular element parts. Additionally, the at least two layers of reinforcement elements may preferably be attached to each other. This attachment can be achieved, for example, by connecting the protrusion part of the first material layer to the notch of the second material layer. According to an exemplary embodiment, one layer of the at least two layers of reinforcement elements may include a lip part, and the other layer of the at least two layers of reinforcement elements includes a notch part for attaching to the lip part.

[0026] Thereby, a snap-fit connection is provided between the layers of the reinforcement element. Thus, no additional attachment elements are required, and the layers will be connected to each other when the reinforcement element is connected to the dielectric filling member.

[0027] According to an exemplary embodiment, and as described above, the body may be formed of a polymer material. According to an exemplary embodiment, the polymer material may be a fluoropolymer, preferably PTFE. Description of the Drawings

[0028] The present disclosure will be described in more detail with reference to the accompanying drawings, which show currently preferred embodiments of the radar level gauge, in which:

[0029] Figure 1 A radar level gauge installed on a tank according to an embodiment of the present invention is shown;

[0030] Figure 2a A dielectric filling member and a structural strengthening element according to an exemplary embodiment are shown;

[0031] Figure 2b A dielectric filling member and a structural strengthening element according to another exemplary embodiment are shown; and

[0032] Figures 3a to 3d Structural strengthening elements according to various exemplary embodiments are shown. Detailed Description of the Embodiments

[0033] Referring to Figure 1 , a radar level gauge (RLG) 100 according to an exemplary embodiment is depicted. The RLG 100 is installed at an upper portion of a tank 102 and is arranged to measure, for example, the depth L of a process content 104 in the tank 102, or the distance from the upper portion of the tank 102 to the surface of the process content 104. The process content 104 can be, for example, a liquid such as gasoline, or a solid material such as a granular mixture.

[0034] The RLG 100 includes an antenna device 114, which includes a transceiver circuit 106, a processing circuit 108, and a signal / power interface 110 that connects to and is powered by a battery 107, all of which are shown very schematically in Figure 1 . The transceiver circuit 106, the processing circuit 108, and the interface 110 are preferably arranged in a measurement unit (not shown), which is mounted to a tank connector 112 made of a metallic material, typically steel. The tank connector 112 includes an antenna mounting structure 116 adapted to be firmly fitted to a portion 118 of the tank 102. Figure 1 An exemplary embodiment is shown in which the antenna mounting structure 116 is bolted to the portion 118 of the tank 102 using bolts 117. Figure 1 The antenna mounting structure 116 depicted in

[0035] is provided as an integral part of the tank connector 112. However, the antenna mounting structure 116 can equally well be formed by additional components connected to the tank connector 112 and the like. The tank connector 112 is adapted to provide a passage (sometimes pressure-sealed) through the wall of the tank for electromagnetic signals, which connects the transceiver circuit 106 to the antenna device 114 to allow signals to propagate into the tank.

[0036] The antenna device 114 further includes a directional antenna 120 having a waveguide portion 122 and a horn portion 124. Here, the horn portion 124 is formed by the tank connector 112, but may also be a separate part attached to the tank connector 112, for example, attached to the tank connector 112 by means of, for example, a threaded fitting.

[0037] The transceiver circuit 106 is configured to generate and transmit an electromagnetic (microwave) transmission signal S T and receive an electromagnetic (microwave) return signal S R . A coupling device such as a probe (not shown) is arranged to couple the transmission signal from the transceiver circuit 106 into the waveguide portion 122.

[0038] The transceiver circuit 106 may be a unit capable of transmitting and receiving electromagnetic signals, or may be arranged as a system including a separate transmitter unit and a receiver unit. The components of the transceiver circuit 106 are typically implemented in hardware and form part of an integrated unit commonly referred to as a microwave unit. For simplicity, the transceiver circuit is referred to as the "transceiver" in the following description.

[0039] The processing circuit 108 is configured to determine the distance between a reference position (such as a passage between the outer and inner sides of the tank) at the top of the tank and the surface of the tank contents by analyzing the transmission signal S T and the return signal S R . The processing typically includes the generation of a tank signal or "echo curve", which includes a plurality of peaks representing reflected signals (echoes) from the interior of the tank. One of the peaks represents the reflected signal (echo) from the surface of the tank contents. Based on the determined distance to the surface, commonly referred to as the ullage, and the known dimensions of the tank 102, process variables such as the fill level L of the tank can be determined.

[0040] The processing circuit 108 may include a microprocessor, a microcontroller, a programmable digital signal processor, or other programmable device. The processing circuit may also or alternatively include an application specific integrated circuit, a programmable gate array or programmable array logic, a programmable logic device, or a digital signal processor. In the case where the processing circuit 108 includes a programmable device such as the above-mentioned microprocessor, microcontroller, or programmable digital signal processor, the processor may also include computer-executable code for controlling the operation of the programmable device. The interface 110 is configured to allow communication of measured values outside the RLG and optionally for power supply to the RLG.

[0041] In use, the transmission signal S generated by the transceiver TCoupled to waveguide section 122, allowed to propagate to horn section 124 and then transmitted into the tank. Transmission signal S T Propagates towards the surface of the tank contents 104, and electromagnetic return signal S R Is caused by reflection in the surface. The return signal is returned by antenna 120, allowed to propagate through the waveguide section, and coupled back to the transceiver by the coupling means.

[0042] In addition, the RLG includes a dielectric filling member 200. The dielectric filling member 200 is microwave transmissive and is at least partially disposed in a cavity 130 formed by the waveguide section 122 and the horn section 124 of the antenna 120. The dielectric filling member 200 is arranged to protect the antenna 120 from the effects of chemicals and from the thermal shock of the contents within the tank 102. According to an exemplary embodiment, and as will be mentioned hereinafter, the dielectric filling member 200 is preferably made of a polymeric material, more preferably made of PTFE. The PTFE material has chemical resistance and water resistance, which are advantageous in the tank environment. PTFE is also advantageous in terms of its temperature resistance characteristics.

[0043] In addition, the dielectric filling member 200 includes a body 202 having a generally conical shape adapted to fit within the horn section 124 of the antenna 120. The base 204 of the conical body 202, i.e., the surface facing the interior of the tank, may have a convex shape to shape the radar beam of the emitted wave in a beneficial manner, and the base 204 of the conical body 202 may also facilitate the dripping of condensate formed on the filling member.

[0044] The dielectric filling member 200 further includes a sealing means 210 for preventing the escape of tank contents into the external environment. The sealing means 210 is disposed between the antenna mounting structure 116 and a portion 118 of the tank 102. The sealing means 210 is disposed around the periphery of the body 202, and the sealing means 210 is preferably formed of the same material as the body to be integrally formed with the body 202.

[0045] According to Figure 1 the example depicted in, the sealing means 210 includes a first sealing portion 214 and a second sealing portion 212, wherein when along the transmission signal direction S TIn the observation, the second sealing portion 212 is disposed above the first sealing portion 214. More specifically, the second sealing portion 212 includes an upper surface 217 configured to abut against the antenna mounting structure 116, and the first sealing portion 214 includes a lower surface 213 configured to abut against a portion 118 of the tank 102. In addition, the first sealing portion 214 and the second sealing portion 212 are each provided as respective annular flanges radially extending from a base portion 220 of a tapered portion of the tapered body 202. The upper surface 211 and the lower surface 213 of the first sealing portion 214 should be understood as opposite surfaces of the first sealing portion 214. Thus, the surface normal of the upper surface 211 has an opposite direction compared to the surface normal of the lower surface 213. The same argument applies to the upper surface 217 and the lower surface 215 of the second sealing portion 214.

[0046] In addition, the RLG further includes a structural reinforcement element 300 disposed between the first sealing portion 214 and the second sealing portion 212. Specifically, the structural reinforcement element 300 is configured to abut against the upper surface 211 of the first sealing portion 214 and is configured to abut against the lower surface 215 of the second sealing portion 212. Thus, the structural reinforcement element 300 is sandwiched between the first sealing portion 214 and the second sealing portion 212 at an opening formed by the first sealing portion 214 and the second sealing portion 212. Further description will be made with reference to Figures 3a to 3d a detailed exemplary embodiment of the structural reinforcement element 300. The structural reinforcement element 300 is preferably formed of a material more rigid than the material of the dielectric filling member. Thus, the stiffness coefficient, generally referred to as Young's modulus, of the structural reinforcement element 300 should preferably be higher than the stiffness coefficient of the dielectric filling member 200. Preferably, the structural reinforcement element 300 is formed of a metallic material such as, for example, steel.

[0047] By positioning the structural reinforcement element 300 between the first sealing portion 214 and the second sealing portion 212 in the sealing device 210, the stiffness of the sealing device 210 is improved, and the dielectric filling member 200 will be more capable of withstanding the negative pressure from the tank 102. Since the coefficient of thermal expansion of the structural reinforcement element 300 is preferably equal to or less than the coefficient of thermal expansion of the first sealing portion and the second sealing portion, the sealing device 210 will also be less sensitive to high temperatures.

[0048] Now referring to Figures 2a to 2b , in which an exemplary embodiment of the sealing device 210 is depicted. In particular, Figures 2a to 2b only the dielectric filling member 200 and the structural reinforcement element 300 are shown. First, look at Figure 2aIn an exemplary embodiment, the sealing device 210 includes the first sealing portion 214 described above. However, instead of using a second sealing portion located above the structural reinforcement element 300, the upper surface 303 of the structural reinforcement element 300 will be arranged to abut against the antenna mounting structure ( Figure 1 in 116). Thus, the structural reinforcement element 300 will be connected between the upper surface 211 of the first sealing portion 214 and the antenna mounting structure.

[0049] According to an example, and as depicted in the embodiment of Figure 2a , the dielectric filling member 200 includes an annular groove 245, and the structural reinforcement element 300 is connected to the annular groove 245. Thus, the structural reinforcement element 300 will be well-connected to the sealing device before the sealing device and the structural reinforcement element 300 are fixed between the antenna mounting structure and the said part of the tank.

[0050] Turning to Figure 2b , which shows a sealing device according to an exemplary embodiment. As can be observed in Figure 2b , the second sealing portion 212 is sintered to the first sealing portion 214. In particular, the outer portion 231 of the second sealing portion 212 is sintered to the first sealing portion 214. Thereby, a circumferentially arranged cavity portion 235 is formed, in which the structural reinforcement element 300 is positioned. The order in which the first sealing portion 214 and the second sealing portion 212 are sintered to each other, and how the first sealing portion 214 and the second sealing portion 212 are sintered to each other naturally depends on, for example, the specific manufacturing process selected.

[0051] During manufacturing, the dielectric filling member 200 is preferably formed together with the first sealing portion 214. The structural reinforcement element 300 is positioned on the upper surface 211 of the first sealing portion 214, preferably in a recess or the like formed by the first sealing portion 214. The formation of the recess is not necessary, but is shown only as an exemplary embodiment. Thereafter, the second sealing portion 212 is provided to the dielectric filling member 200 by sintering the second sealing portion 212 to the dielectric member 200 and to the first sealing portion 214. Thereby, the cavity portion 235 forms a closed portion of the sealing device 210.

[0052] Figure 2b The sealing device 210 depicted in Figure 1In a similar manner as described in the embodiments, it is connected between the antenna mounting structure and the said part of the tank. Thus, the lower surface 213 of the first sealing part 214 is arranged to abut against the said part of the tank, while the upper surface 211 of the first sealing part 214 is arranged to abut against the structural strengthening element 300. The lower surface 215 of the second sealing part 212 is also arranged to abut against the structural strengthening element 300, while the upper surface 217 of the second sealing part 212 is arranged to abut against the antenna mounting structure.

[0053] To describe the structural strengthening element 300 in more detail, refer to Figures 3a to 3d which shows different exemplary embodiments of the structural strengthening element 300. First, refer to Figure 3a where the structural strengthening element 300 includes a first element part 302, a second element part 304, a third element part 306, and a fourth element part 308. The first element part 302 is connected to the second element part 304 around the periphery of the main body 202. The first element part 302 and the second element part 304 are each formed as a semi-circle. The first element part 302 and the second element part 304 are connected to each other by means of a protrusion 303 connected to a notch 305. In the Figure 3a embodiment depicted, the first element part 302 includes a protrusion 303 that extends circumferentially at the first end of the first element part 302 and a notch 305 at the second end of the first element part 302. In a similar manner, the second element part 304 includes a protrusion 303 that extends circumferentially at the first end of the second element part 304 and a notch 305 at the second end of the second element part 304. The protrusion 303 of the first element part 302 is arranged to cooperate with the notch 305 of the second element part 304, and the protrusion 303 of the second element part 304 is arranged to cooperate with the notch 305 of the first element part 302. Thus, a snap-fit connection is provided between the protrusion 303 and the notch 305. However, it should be readily understood that the first element part 302 may be provided with only protrusions, and the second element part 304 may be provided with only notches. Additionally, more than the number of protrusions / notches depicted in Figure 3a may be provided.

[0054] Furthermore, the third element part 306 and the fourth element part 308 are connected to each other in a manner similar to the connection between the first element part 302 and the second element part 304. Thus, the third element part 306 and the fourth element part 308 are also provided with protrusions 303 and notches 305.

[0055] The first element part 302 and the second element part 304 form the strengthening elements of the first layer 310, while the third element part 306 and the fourth element part 308 form the strengthening elements of the second layer 312. As Figure 3aAs depicted, the first layer 310 and the second layer 312 are arranged one above the other, wherein the first layer 310 is rotated 90 degrees relative to the second layer 312. Thus, the joint of the first element portion 302 and the second element portion 304, that is, the positions where the protrusion and the notch are located, will not overlap with the corresponding joints of the third element portion 306 and the fourth element portion 308. When observing along the microwave transmission signal direction S T the first layer 310 and the second layer 312 form the thickness of the structural reinforcement element.

[0056] Referring Figure 3b , a structural reinforcement element 300' according to another exemplary embodiment is depicted. Figure 3b The structural reinforcement element 300' in also includes a first element 302' and a second element 304' that can be connected to each other around the periphery of the main body 202. In the Figure 3b depicted example, the first element portion 302' includes a protrusion 303' located at the corresponding end surface portion 307' of the semi-circular first element portion 302'. The protrusion 303' extends in the direction between the first sealing portion and the second sealing portion. The second element portion 304' includes a notch 305' located at the corresponding end surface portion 309' of the semi-circular second element portion 304'. The notch 305' is arranged along the direction of the microwave transmission signal.

[0057] The end surface portion 307' of the semi-circular first element portion 302' preferably includes a thickness that is thinner than the thickness of the remaining first element portion 302'. Similarly, the end surface portion 309' of the semi-circular second element portion 304' preferably includes a thickness that is thinner than the thickness of the remaining second element portion 304'. As Figure 3b shown, the end surface portion 307' of the semi-circular first element portion 302' is arranged to overlap with the end surface portion 309' of the semi-circular second element portion 304', wherein the protrusion 303' and the notch 305' are snap-fitted to connect the first element portion 302' and the second element portion 304' to each other.

[0058] To describe a structural reinforcement element 300'' according to yet another exemplary embodiment, refer to Figure 3c . Figure 3c The embodiment depicted in includes a reinforcement element of two layers 310'', 312'' connected to each other. The first layer 310'' is formed by a first element portion 302'' and a second element portion 304'', while the second layer 312'' is formed by a third element portion 306'' and a fourth element portion 308''. The first element portion 302'' and the second element portion 304'' include notch portions 330'' provided at their peripheries, and the third element portion 306'' and the fourth element portion 308'' include lip portions 340''.

[0059] During Figure 3c the assembly of the structural reinforcement element 300” in

[0060] Finally referring to Figure 3d , Figure 3d FIG. shows yet another exemplary embodiment of the structural reinforcement element 300’”. As observed, the structural reinforcement element 300’” includes a plurality of through holes 360’”. The through holes 360’” are arranged to extend in a direction between the first sealing portion 214 and the second sealing portion 212 when the structural reinforcement element 300’” is connected to the sealing device. When the structural reinforcement element 300’” is disposed between the first sealing portion 214 and the second sealing portion 212, the second sealing portion 212 can be sintered to the first sealing portion 214 at the plurality of through holes 360’” to strengthen the connection between the first sealing portion 214 and the second sealing portion 212.

[0061] As Figure 3d depicted, the structural reinforcement element 300’” is provided as a one-piece element. This embodiment is particularly suitable for use in combination with the embodiment described above with respect to Figure 2b .

[0062] Although the structural reinforcement element 300’” is depicted as a one-piece element in Figure 3d , the structural reinforcement element 300’” can also be provided with a first element portion and a second element portion and with two or more layers 310, 312 as depicted, for example, in Figure 3a . Thus, it should be readily understood that Figures 3b to 3c the structural reinforcement element depicted in Figure 3d can also be provided with a plurality of through holes in a manner similar to the embodiment depicted in

[0063] Those skilled in the art will recognize that the present invention is in no way limited to the above preferred embodiments. On the contrary, within the scope of the appended claims, many modifications and variations are possible. For example, the shape and form of the structural reinforcement elements may differ from the illustrated examples depending on the exact application. The plurality of through-holes 360''' may, for example, have different shapes and sizes. In addition, compared with the illustrated examples, the first sealing portion and the second sealing portion may differ in shape and design. Further, Figure 3a the structural reinforcement element 300 depicted in Figure 3b may be formed of a single layer of reinforcement elements, while the embodiment depicted in

Claims

1. A radar level gauge for determining a process variable of a product in a tank by using an electromagnetic measurement signal, the radar level gauge comprising: An antenna device including an antenna mounting structure, the antenna device being adapted to direct a microwave transmission signal towards the product and to return a reflection of the microwave transmission signal from the surface of the product; A dielectric filling member provided in the antenna device, the dielectric filling member including a body and a sealing device for preventing the escape of tank contents into the external environment, the sealing device being provided around the periphery of the body, and the sealing device including a first sealing portion positioned between a part of the antenna mounting structure and a part of the tank, wherein a lower surface of the first sealing portion is arranged to abut against the part of the tank, wherein the sealing device and the body are formed as one piece and made of the same material; and A structural reinforcement element formed of a material having a stiffness coefficient higher than that of the sealing device, the structural reinforcement element being provided around the periphery of the body and configured to prevent the dielectric filling member from being pressed towards the interior of the tank when the tank is exposed to negative pressure, the structural reinforcement element being arranged to abut against an upper surface of the first sealing portion such that, when viewed in the direction of the microwave transmission signal, the first sealing portion is positioned above the part of the tank and below the structural reinforcement element, wherein an upper surface of the structural reinforcement element is arranged to abut against the antenna mounting structure, whereby the first sealing portion is spaced apart from the antenna mounting structure by the structural reinforcement element, and wherein the dielectric filling member includes an annular groove into which the structural reinforcement element is connected.

2. The radar level gauge according to claim 1, wherein The structural reinforcement element includes a first element portion and a second element portion connected to each other around the body.

3. The radar level gauge according to claim 2, wherein, The first element portion and the second element portion are formed in a semi-circular shape.

4. The radar level gauge according to claim 2, wherein, The first element portion includes a protrusion, and the second element portion includes a notch, wherein the protrusion is connected to the notch when the structural reinforcement element is connected around the body.

5. The radar level gauge according to claim 1, wherein, When viewed in the direction of the microwave transmission signal, the structural reinforcement element includes at least two layers of reinforcement elements.

6. The radar level gauge according to claim 5, wherein, One layer of the at least two layers of reinforcement elements includes a lip portion, and another layer of the at least two layers of reinforcement elements includes a notch portion for attaching to the lip portion.

7. The radar level gauge according to claim 1, wherein The structural reinforcement element is formed of a metallic material.

8. The radar level gauge according to claim 1, wherein The body is formed of a polymer material.

9. The radar level gauge according to claim 8, wherein, The polymer material is a fluoropolymer.

10. The radar level gauge according to claim 9, wherein, The polymer material is polytetrafluoroethylene.

11. A radar level gauge for determining a process variable of a product in a tank by using an electromagnetic measurement signal, the radar level gauge comprising: An antenna device, the antenna device including an antenna mounting structure, the antenna device being adapted to direct a microwave transmission signal towards the product and to return reflections of the microwave transmission signal from the surface of the product; A dielectric filling member, the dielectric filling member being disposed in the antenna device, the dielectric filling member including a body and a sealing means for preventing the contents of the can from escaping into the external environment, the sealing means being disposed around the periphery of the body, and the sealing means including a first sealing portion and a second sealing portion, the first sealing portion being positioned between a part of the antenna mounting structure and a part of the can, the second sealing portion including an upper surface arranged to abut against the part of the antenna mounting structure, wherein the lower surface of the first sealing portion is arranged to abut against the part of the can, wherein the sealing means and the body are formed as one piece and made of the same material; and A structural reinforcement element, the structural reinforcement element being disposed around the periphery of the body, the structural reinforcement element being arranged to abut against the upper surface of the first sealing portion such that, when viewed in the direction of the microwave transmission signal, the first sealing portion is positioned above the part of the can and below the structural reinforcement element, whereby the first sealing portion is spaced apart from the antenna mounting structure by the structural reinforcement element, wherein the sealing means includes a circumferentially arranged cavity portion formed by sintering an outer end portion of the second sealing portion to the first sealing portion, and the structural reinforcement element is encapsulated in the circumferentially arranged cavity portion.

12. The radar level gauge according to claim 11, wherein, The body has a generally conical portion, and the first sealing portion and the second sealing portion are each provided as respective annular flanges radially extending from a base portion of the conical portion.

13. The radar level gauge according to claim 11, wherein, The structural reinforcement element is sandwiched between the first sealing portion and the second sealing portion.

14. The radar level gauge according to claim 11, wherein, The structural reinforcement element includes a plurality of through-holes extending in a direction between the first sealing portion and the second sealing portion, and the first sealing portion and the second sealing portion are connected to each other at the plurality of through-holes by sintering the first sealing portion to the second sealing portion.

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