Cover element for use in a flow meter

Abstract

The invention relates to a cover element for a flow measuring device, comprising a positive-locking receptacle for the bypass channel and pin-shaped flow resistance elements for throttling the fluid flow and fixing the cover element. The invention further relates to a flow measuring device comprising a main channel, a bypass channel, a measuring element, and such a cover element, thereby achieving a cost-effective and simple implementation of the bypass channel.

Description

[0001] The present invention relates to flow measuring devices and associated components for fluid systems, in particular cover elements for integration into such flow measuring devices.

[0002] Flow measuring devices are used in a wide variety of applications to determine the flow rate of liquids or gases. One method for flow measurement, known, for example, from DE 202 08 716 U1 or EP 1 464 928 A2, involves the use of a main channel through which the medium flows and a bypass channel that diverts a portion of the medium. The bypass channel and main channel are connected by branch lines. A measuring element is installed in the bypass channel to detect the flow rate.

[0003] A common method for influencing the flow rate in the bypass channel is the use of throttles or orifices in the main channel. These elements create a pressure drop that determines the flow rate through the bypass channel. However, this method can have limitations, as optimizing the pressure drop in the main channel often conflicts with other design criteria.

[0004] The use of nozzle inserts in branch lines for flow limitation is known from the prior art. These are machined sleeves with nozzle bores of very small diameter, e.g., 0.2 mm. Their production is relatively expensive due to the precision required for creating such bores. Furthermore, these components often require additional parts and assembly steps, which increases the overall cost and complexity of the flow metering device.

[0005] Document US 2013 / 0098486A1 discloses a flow sensor comprising a main flow channel containing a laminar flow element and a bypass channel. The bypass taps, which fluidically connect the main flow channel to the bypass channel, are located within the laminar flow element. A flow restrictor is also provided in the bypass channel.

[0006] Against this background, the task is to propose a cost-effective and simple implementation of the bypass channel in a flow meter with a bypass configuration. In particular, a solution that is advantageous from a manufacturing perspective should be found that simultaneously ensures precise flow control and reliable operation of the flow meter.

[0007] The object of the invention is achieved by a lid element having the features of claim 1 and by a flow measuring device having the features of claim 7. Advantageous embodiments of the invention are specified in the dependent claims.

[0008] According to the invention, a cover element for use in a flow meter in a fluid system comprises: a cover for the positive-locking reception of the bypass channel; and two pin-shaped flow resistance elements with a cross-section that is at least partially non-circular. The flow resistance elements are designed for arrangement in branch lines of the flow meter, thereby providing a fixing and holding function for the cover element, simultaneously achieving a throttling function for the fluid in the branch line, and generating a focused fluid jet when the fluid exits the branch line into the bypass channel. Preferably, the cover element is manufactured as an injection-molded part. An advantage of this design is the very cost-effective manufacturing and the integration of several functions in a single component.

[0009] According to a preferred embodiment of the invention, the cover includes a groove for forming the bypass channel. An advantage of this design is the simple assembly and defined positioning of the bypass channel.

[0010] According to a preferred embodiment of the invention, the flow resistance elements are designed as pins that project into the branch lines. An advantage of this design is the simple implementation of the throttling function.

[0011] According to a preferred embodiment of the invention, further comprising a flow control device for realizing a homogeneous and symmetrical flow profile at the measuring element. An advantage of this design is the improved measuring accuracy, especially in very small designs, i.e., with a distance between the branch lines of approximately 10-15 mm.

[0012] According to a preferred embodiment of the invention, the flow control device comprises an impact surface and / or a vortex chamber. An advantage of this design is its compact construction and effective flow control.

[0013] In a second aspect, the invention relates to a flow measuring device for a fluid system. According to the invention, this flow measuring device comprises: a main channel for guiding a fluid flow; a bypass channel which is connected to the main channel via at least two branch lines; a measuring element for detecting the flow rate in the bypass channel; and the aforementioned cover element, wherein the cover element positively engages the bypass channel and the flow resistance elements are arranged in the branch lines.

[0014] According to a preferred embodiment of the invention, the measuring element is arranged on a circuit board that is attached to the cover element. An advantage of this design is the simple mounting and electrical contacting of the measuring element.

[0015] According to a preferred embodiment of the invention, wherein the measuring element is a thermal measuring element, wherein measuring elements for e.g. for detecting pressure and temperature are also conceivable in principle.

[0016] The invention will now be explained in more detail using exemplary embodiments and with reference to the drawings.

[0017] They show schematically: Fig. 1 a sectional view of a flow measuring device with the cover element according to the invention; Fig. 2 two perspective exploded views of a possible embodiment of the cover element with impact surface and settling chamber and with key surface; Fig. 3 two perspective exploded views of another possible embodiment of the cover element with vortex / expansion chamber and with key surface; Fig. 4 Two perspective exploded views of another possible embodiment of the lid element with impact surface and settling chamber and with passage; Fig. 5 Two perspective exploded views of another possible embodiment of the cover element with vortex / expansion chamber and with passage.

[0018] In the following description of preferred embodiments, identical reference numerals denote identical or comparable components.

[0019] Fig. Figure 1 shows a schematic sectional view of a DMV flow meter, which is used for the precise measurement of fluid flows in a fluid system. The DMV flow meter is based on the principle of bypass measurement, in which a small portion of the main fluid flow is diverted into a separate bypass channel to measure the flow rate there.

[0020] The main channel 1 represents the primary flow path for the fluid. Within the main channel 1 is an orifice 2, which acts as a flow resistance element and enables bypass measurement. This orifice 2 creates a defined pressure drop in the main channel 1, which depends on the total flow rate.

[0021] This pressure drop is an important parameter for the subsequent flow rate determination. Orifice 2 can be implemented in various designs, for example as a simple narrowing of the channel cross-section or as a more complex throttling device.

[0022] Two branch lines 3 extend from the main channel 1. These branch lines 3 connect the main channel 1 to the bypass channel 5. This arrangement diverts a partial flow of fluid into the bypass channel 5. The dimensions and arrangement of the branch lines 3 are important design parameters that influence the proportion of the diverted partial flow and thus the flow measurement.

[0023] Each of the branch lines 3 is equipped with a flow restrictor element 4. These flow restrictor elements 4 are designed as pin- or cam-shaped components with a non-circular cross-section. The non-circular cross-section of the flow restrictor element 4 causes a controlled throttling of the fluid flow and generates a focused jet upon entry of the fluid into the bypass channel 5. This focusing of the jet is an essential feature of the invention, as it forms the basis for the subsequent flow control.

[0024] The bypass channel 5 is formed by a cover element DE in the form of a groove 5a, which is advantageously manufactured as an injection-molded part. The cover element DE is a central component of the DMV flow metering device, as it forms both the bypass channel 5 and accommodates the two flow resistance elements 4. The flow resistance elements 4, which are press-fitted into the branch lines 3, fix and permanently hold the cover element DE in place.

[0025] A circuit board 7 is attached to the cover element DE, which includes the measuring element 6 for detecting the flow rate in the bypass channel 5. The measuring element 6 can, for example, be a sensor for measuring heat dissipation. The choice of measuring element 6 depends on the specific requirements of the application.

[0026] The areas at the two outer ends of the cover element DE are designated as flow control devices (SBE). The flow control device SBE is a central element of the invention and serves to selectively modify and then homogenize the flow profile of the fluid exiting the branch line 3 within a very small space. This flow control ensures that the measuring element 6 detects a homogeneous and symmetrical flow, resulting in more precise and reliable flow measurement. The double-sided arrangement of the flow control device SBE enables bidirectional flow measurement, so that the setup is independent of the flow direction in the main channel 1. The exact operation of the flow control device SBE is explained in more detail in the following figures.

[0027] The in Fig. The arrangement shown in Figure 1 thus enables precise and reliable flow measurement in a fluid system. The combination of the flow resistance elements 4 with non-circular cross-sections and a flow control device (FCD) ensures a homogeneous flow at the measuring element 6, regardless of the flow direction in the main channel 1. This results in high measurement accuracy even with small to very small designs, i.e., with a distance between the branch lines of approximately 10-15 mm.

[0028] Fig. Figure 2 shows two perspective exploded views of a possible embodiment of the cover element with key surface. The cover element DE forms the bypass channel 5 in the shape of the groove 5a and comprises two pin- or cam-shaped flow resistance elements 4. The figure shows two views of the cover element DE: a top view and a perspective view from below, which illustrates the details of the flow control device SBE.

[0029] The bypass channel 5 initially extends longitudinally through the cover element DE and is deflected by 180° at both ends of the cover element DE, thereby increasing the overall length of the bypass channel 5. A feedthrough 12 for the measuring element is located in the middle of the bypass channel 5. This feedthrough 12 allows the measuring element 6 to be positioned (not shown in this figure, see [reference]). Fig. 1) in bypass channel 5, so that it can detect the flow of the fluid.

[0030] In this embodiment, the flow resistance elements 4 are implemented as an integral component of the cover element DE at the beginning and end of the flow path in the bypass channel 5. Due to the 180° bend in the bypass channel 5, this embodiment is particularly suitable for very small and compact flow measuring devices, e.g., with a distance of approximately 12 mm between the flow resistance elements 4.

[0031] The flow resistance elements 4 each have a key surface 9. This key surface 9 is a flat, planar surface that forms part of the cross-section of the flow resistance element 4. The key surface 9 creates a defined narrowing of the flow cross-section in the branch lines 3, thereby achieving the desired pressure drop and the focusing of the fluid flow.

[0032] In this embodiment, the flow control device SBE comprises a baffle surface 10 and a constriction 13 between the flow resistance elements 4 and an inner wall of the bypass channel 5.

[0033] The baffle surface 10, also part of the inner wall of the bypass channel 5, is located opposite the outlet of the flow resistance element 4 and serves to break up and swirl the focused jet of fluid exiting the flow resistance element 4. The constrictions 13 between the flow resistance elements 4 and each inner wall of the bypass channel 5 create a nozzle effect, thereby straightening the flow profile. The calming chamber 11, as part of the bypass channel 5, connects to the constrictions when viewed from the flow path. In the calming chamber 11, the flow can further calm down and develop a homogeneous and symmetrical flow profile before the fluid reaches the measuring element 6.

[0034] By integrating the bypass channel 5, the flow resistance elements 4, and the flow control device SBE into a single injection-molded part, the number of individual parts and assembly costs are reduced. At the same time, optimal flow guidance in the bypass channel 5 is achieved in a very small space through the targeted shaping of the key surface 9, the impact surface 10, and the settling chamber 11.

[0035] Fig. Figure 3 shows two perspective exploded views of another possible embodiment of the cover element DE, which is manufactured as an injection-molded part. Similar to in Fig. 2 The cover element DE forms the bypass channel 5 in the form of the groove 5a and includes the flow resistance elements 4. The figure again shows two views of the cover element DE: a top view (above) and a perspective view from below (below), which illustrates the details of the flow control device SBE.

[0036] The bypass channel 5 extends essentially lengthwise through the cover element DE. In the center of the bypass channel 5 is a feedthrough 12 for the measuring element. This feedthrough 12 allows the arrangement of the measuring element 6 (not shown in this figure, see [reference]). Fig. 1) in bypass channel 5, so that it can detect the flow of the fluid.

[0037] This embodiment is suitable for a opposite Fig. A slightly larger design of the cover element DE is provided, so that no 180° bends of the bypass channel 5 are required. The essentially identical length of the bypass channel 5 therefore extends in one continuous length. In the present embodiment, the distance between the flow resistance elements 4 is approximately 25 mm.

[0038] The flow resistance elements 4 exhibit, as in Fig. Each of the two elements has a key surface 9, i.e., a flat, planar surface that forms part of the cross-section of the flow resistance element 4. The key surface 9 creates a defined narrowing of the flow cross-section, thereby achieving the desired pressure drop and the focusing of the fluid flow.

[0039] In this embodiment, the flow control device SBE comprises a vortex / expansion chamber 8 and two constrictions 13. The vortex / expansion chamber 8 is formed as part of the bypass channel 5. Within this chamber 8, the focused jet of fluid exiting the key surface 9 can expand and become turbulent. This turbulence selectively modifies the flow profile, effectively "zeroing" it and then rebuilding it as the flow progresses. The shape and size of the vortex / expansion chamber 8 are important design parameters that determine the effectiveness of the flow control. The constrictions 13 between the flow resistance elements 4 and each inner wall of the bypass channel 5 further reduce the already existing flow. Fig. The nozzle function mentioned in point 2 achieves this by straightening the flow profile after the initial "zeroing" process. Further along the bypass channel 5, the flow can calm down and develop a homogeneous and symmetrical flow profile before the fluid reaches the measuring element 6.

[0040] Fig. Figure 4 shows two perspective exploded views of another possible embodiment of the cover element DE, which is manufactured as an injection-molded part. Similar to the previous figures, the cover element DE forms the bypass channel 5 in the shape of the groove 5a and includes the flow resistance element 4. The figure again shows two views of the cover element DE: a top view and a perspective view from below, which illustrates the details of the flow control device SBE.

[0041] The bypass channel 5 extends through the cover element DE and is constructed as already described in the embodiment according to Fig. 2 deflected by 180° at both ends.

[0042] In the middle of the bypass channel 5 is a feedthrough 12 for the measuring element. This feedthrough 12 allows the measuring element 6 to be positioned (not shown in this figure, see [reference]). Fig. 1) in bypass channel 5, so that it can detect the flow of the fluid.

[0043] Unlike Fig. 2 and Fig. In this embodiment, the flow resistance elements 4 are not formed by key surfaces 9, but by two passages 14, preferably in the form of an eccentric bore in the pin-shaped flow resistance element 4. Each passage 14 represents a defined opening in the flow resistance element 4 through which the fluid flows. The size and shape of the passage 14 determine the flow resistance and the focusing of the fluid flow.

[0044] In this embodiment, the flow control device SBE comprises an impact surface 10 and the constrictions between the flow resistance elements 4 and each inner wall of the bypass channel 5, thereby achieving the desired nozzle function for the purpose of straightening the flow profile. The fluid then reaches the calming chamber 11. This design essentially corresponds to the embodiment according to [reference to relevant figure]. Fig. 2, whose description is referenced in this regard.

[0045] Fig. Figure 5 shows two perspective exploded views of another possible embodiment of the cover element DE, which is manufactured as an injection-molded part. Similar to the previous figures, the cover element DE forms the bypass channel 5 and includes the flow resistance element 4. The figure again shows two views of the cover element DE: a top view and a perspective view from below, which clarifies the details of the flow control device SBE.

[0046] In this embodiment, the flow resistance elements 4 are again formed not with key surfaces 9, but with two passages 14, preferably in the form of an eccentric bore in the pin-shaped flow resistance element 4. Each passage 14 represents a defined opening in the flow resistance element 4 through which the fluid flows. The size and shape of the passage 14 determine the flow resistance and the focusing of the fluid flow.

[0047] The design of the flow control device SBE essentially corresponds to the embodiment according to Fig. 3, whose description is referenced in this regard. Reference symbol list DMV flow meter DE Lid element SBE flow control device 1 Main channel 2 aperture 3 branch lines 4 Flow resistance element 5 Bypass channel 5a Nut 6 measuring element 7 circuit board 8 Vortex / Expansion Chamber 9 key area 10 Impact area 11 Calming Chamber 12. Implementation for the measuring element 13 Narrowing 14 Passage

Claims

[1] Cover element (DE) for use in a flow meter (DMV) in a fluid system, comprising: ◯ a cover for the form-fitting reception of a bypass channel (5); and ◯ two pin-shaped flow resistance elements (4) with a cross-section that is at least partially non-circular, wherein the flow resistance elements (4) are arranged for placement in branch lines (3) of the flow measuring device (DMV), thereby realizing a fixing and holding function of the cover element (DE), simultaneously achieving a throttling function of the fluid in the branch line (3), and generating a bundled fluid jet when the fluid exits the branch line (3) into the bypass channel (5). [2] Cover element (DE) according to claim 1, wherein the cover comprises a groove (5a) for forming the bypass channel (5). [3] Cover element (DE) according to claim 1 or 2, wherein the flow resistance elements (4) are designed as pins that project into the branch lines (3). [4] Cover element (DE) according to one of claims 1 to 3, further comprising a flow control device (FCD) for homogenizing the fluid flow. [5] Cover element (DE) according to claim 4, wherein the flow control device (SBE) comprises a baffle surface (10) and / or a vortex chamber (8). [6] Lid element (DE) according to one of claims 1 to 5, wherein the lid element (DE) is designed as an injection molded part. [7] Flow metering device (DMV) for a fluid system, comprising: ◯ a main channel (1) for guiding a fluid flow; ◯ a bypass channel (5) which is connected to the main channel (1) via at least two spur lines (3); ◯ a measuring element (6) for detecting the flow rate in the bypass channel (5); and ◯ a cover element (DE) according to one of claims 1 to 6, wherein the cover element (DE) receives the bypass channel (5) in a form-fitting manner and the flow resistance elements (4) are arranged in the branch lines (3). [8] Flow metering device (DMV) according to claim 7, wherein the measuring element (6) is arranged on a circuit board (7) which is attached to the cover element (DE). [9] Flow metering device (DMV) according to claim 8, wherein the measuring element (6) is a thermal measuring element. [10] Flow metering device (DMV) according to one of claims 7, 8 or 9, wherein the branch lines (3) are arranged tangentially to the main channel (1).

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