Method for equipping a Coriolis mass flow meter with electrical connections

Abstract

Method (1) for at least partially equipping a Coriolis mass flow meter (2) with electrical connections (3), wherein the Coriolis mass flow meter (2) comprises as structural parts at least one measuring tube (5a, 5b), at least one actuator receptacle (6a, 6b) attached to the measuring tube (5a, 5b), and at least one sensor receptacle (7a-7d) attached to the measuring tube (5a, 5b), characterized in that the electrical connections (3) are applied to at least one of the structural parts of the Coriolis mass flow meter (2) by a machine printing process, wherein the electrical connections (3) are printed onto the measuring tube (5a, 5b) as the at least one structural part, and that electrical connections (3) which serve for the electrical power supply of electrical or electronic components of the Coriolis mass flow meter (2) or for the transmission of signals are printed onto the measuring tube (5a, 5b).5b) are guided along paths with minimal stretching or compression.

Description

[0001] The invention relates to a method for at least partially equipping a Coriolis mass flow meter with electrical connections, wherein the Coriolis mass flow meter comprises, as structural components, at least one measuring tube, at least one actuator mount attached to the measuring tube, and at least one sensor mount attached to the measuring tube. Furthermore, the invention also relates to a Coriolis mass flow meter with structural components comprising at least one measuring tube, at least one actuator mount attached to the measuring tube, and at least one sensor mount attached to the measuring tube, as well as electrical connections connected to the measuring tube.

[0002] Coriolis mass flow meters of the type described above, and thus also methods for manufacturing such Coriolis mass flow meters or for equipping Coriolis mass flow meters with electrical connections, have been well known in the art for several decades. Besides the most fundamental structural component, the measuring tube, Coriolis mass flow meters often also have other structural components, such as connection flanges at the inlet and outlet ends of the measuring tube, a housing to protect the measuring tube and the evaluation electronics connected to it, and often stiffening bridges between the measuring tube flanges to provide the Coriolis mass flow meter with the necessary mechanical stability when installed in the process.

[0003] During operation, the measuring tube is excited into vibration, often in the fundamental mode at its natural frequency by means of an actuator mounted in the actuator housing. The measured variables are the inlet and outlet vibrations of the measuring tube in the second vibration mode, with the phase difference between the inlet and outlet vibrations representing a measure of the mass flow rate. The measured vibrations have a very small amplitude. With homogeneous media, accuracies of approximately 0.04% of the measured value can be achieved with high-quality Coriolis mass flow meters. This illustrates the extreme precision required in the manufacture, calibration, and operation of Coriolis mass flow meters, and every effort must be made to minimize potential interference effects, non-reproducible boundary conditions, and manufacturing tolerances.

[0004] From JP H09-250 940 A, a Coriolis mass flow meter is known which, in addition to a measuring tube, has an actuator mount and two sensor mounts. The electrical connections are made by a flexible conductor strip that is glued to the measuring tube.

[0005] From EP 0 080 535 A1, a sensor for a magnetic-inductive flowmeter with a rigid measuring tube made of ceramic is known. To create electrical connections, a platinum paste is applied to the measuring tube and heated.

[0006] DE 20 2008 017 787 U1 also describes a magnetic-inductive flowmeter. The electrical conductors are implemented as printed circuit boards that are embedded in the plastic measuring tube during its manufacture.

[0007] German patent DE 298 20 498 U1 discloses a measuring tube for fluid media. To allow electrical conductors to be attached to the measuring tube, a metallic layer is first applied. Subsequently, part of the metallic layer is treated by engraving or laser ablation (evaporation) to create insulating areas.

[0008] Against this background, the present invention aims to provide a method for equipping a Coriolis mass flow meter with electrical connections, which reduces manufacturing tolerances and allows the Coriolis mass flow meter to be manufactured and operated with higher accuracy and reliability.

[0009] The previously identified and derived problem is solved according to the invention in the method described at the outset by applying the electrical connections to at least one structural part of the Coriolis mass flow meter by a mechanical printing process, wherein the electrical connections are printed onto the measuring tube as the at least one structural part, and that the electrical connections, which serve for the electrical power supply of electrical or electronic components of the Coriolis mass flow meter or for the transmission of signals, are guided on the measuring tube via such paths with minimal elongation or compression.

[0010] The invention is based on the initial finding that there are opportunities for improvement, particularly in the area of ​​wiring and electrification of the various electrical components of a Coriolis mass flow meter. This is due, in part, to the fact that the electrical connections in a Coriolis mass flow meter, for example, the connections to the actuators and sensors on the measuring tube, are implemented using cables that are usually installed manually. These cables are routed over the structural components of the Coriolis mass flow meter and secured to these components—including the measuring tube—by adhesive.Manual application of the cable routing naturally leads to variations in the cable routing, the amount of material used, and thus the applied mass. This affects both the cables themselves and the connectors used to attach the cables to the structural components. In the prior art, the cables are often fixed to the structural components using tape or adhesive dots applied close together – for example, a few millimeters apart – to the cable to be fixed. These dots touch the measuring tube laterally, thus securing the cable.

[0011] The influence on the measuring tube, and thus on its dynamic movement, is noticeable. For example, the application of cables to the measuring tube can have a significant impact on the zero point of mass flow measurement.

[0012] In the inventive method of producing the electrical connection by means of a machine-based printing process onto a structural component of the Coriolis mass flow meter, the potential for errors associated with manual application is avoided, and very high repeatability is achieved in the realization of the electrical connections. This repeatability relates to the geometric orientation of the electrical connections on the structural components, the applied masses on the structural components, and also the electrical properties of the electrical connections, such as the resistance between the starting point and the endpoint of the electrical connection.

[0013] In principle, all printing processes capable of applying conductive materials to a substrate are suitable for automated printing. For example, in usable printing processes, electrically conductive liquid or paste-like substances are printed onto the structural components using a printhead that precisely dispenses the substances. This automated printing process is preferably robot-assisted within the production line of the Coriolis mass flow meter, where the structural components occupy a well-defined position and the printhead can apply the conductive substance with high accuracy. Suitable automated printing methods include inkjet printing, aerosol jet printing, and screen printing.It is also possible to use machine printing technologies, in which, for example, a plastic that is initially non-conductive or only slightly conductive is applied to the structural component, with the electrical connections being created by activating specific areas of the plastic using a laser and by subsequent stronger metallization. These technologies are sometimes also classified as 3D printing.

[0014] According to a further development of the proposed method, an electrically insulating coating is applied to the structural component, and the electrical connections are printed onto this coating. This is particularly advantageous when the structural component itself is electrically conductive.

[0015] According to a further embodiment of the invention, the printed electrical connections are at least partially coated with an electrically insulating layer. This insulating layer can also be produced using a machine printing process. This measure serves both to protect the electrical connections and to ensure the safety of the electrical equipment. The electrically insulating coating may also be necessary to meet certain explosion protection requirements.

[0016] An advantageous embodiment of the method is characterized by the fact that the endpoints, or the starting and ending points, of the printed electrical connections are designed as flat surfaces, so that they can be used for attaching metallic conductors using a joining technique. These metallic conductors are particularly suitable for wires leading to electrical modules, such as drives, motion sensors, or evaluation units. Thermal joining techniques such as soldering or welding are especially appropriate joining techniques. In a particular embodiment of the method, the flat endpoints of the electrical connections are designed to have a greater layer thickness than the printed conductor tracks in order to withstand the mechanical and thermal stresses of the joining technique without damage.

[0017] According to the invention, the measuring tube, as a structural component of the Coriolis mass flow meter, is provided with electrical connections by means of a printed marking. Since the measuring tube is the actual sensor of the Coriolis mass flow meter, it is particularly advantageous if the electrical connections cause minimal mechanical interference, which is ensured by the printing process used to create the electrical connections.

[0018] When printing electrical connections onto the measuring tube as a structural component, it has proven particularly advantageous to apply the electrical connections to the measuring tube from a starting point to an end point using a machine printing process, at least according to one of the following variants: - between the actuator recording and one of the sensor recordings, - if two sensor images are present, between the two sensor images, - if at least one gusset plate is present on the tailpipe side, between the sensor mount and the gusset plate, - if two end-pipe-side gusset plates are present, between the gusset plates.

[0019] In the inventive printing of electrical connections onto the measuring tube, it is provided that such electrical connections, which serve to supply power to electrical or electronic components of the Coriolis mass flow meter or to transmit signals (measurement signals, control signals), are routed along paths with minimal strain or compression on the measuring tube. This is advantageous because the electrical connections are subjected to the least mechanical stress along this path. Paths with minimal strain or compression can be determined, for example, intuitively using numerical simulation methods (finite element, boundary).

[0020] In a further development of the method, the electrical connections at the areas of interest are printed as strain gauges, particularly in the form of meandering conductor tracks. The conductor tracks are oriented in the direction in which they are intended to measure any strain or compression, as this results in the greatest change in resistance.

[0021] In a further advantageous embodiment of the method, the electrical connections in areas of interest are printed as thermistors, i.e., in particular using a material with a resistance coefficient that is as constant as possible.

[0022] The implementation of strain gauges or thermistors using a pressure-based process on the measuring tube offers particularly elegant solutions, as the fastening of sensor elements designed as components always presents the challenge of securing them.

[0023] The previously derived problem is solved in the Coriolis mass flow meter described at the beginning, with the structural components already discussed several times here, by applying the electrical connections to at least one of the structural components of the Coriolis mass flow meter using a machine printing process, wherein the electrical connections are printed onto the measuring tube as the at least one structural component, and that electrical connections serving the electrical power supply of electrical or electronic components of the Coriolis mass flow meter or the transmission of signals are routed on the measuring tube via paths with minimal elongation or compression.

[0024] Specifically, there are numerous ways to further develop the method for equipping a Coriolis mass flow meter with electrical connections and a corresponding Coriolis mass flow meter according to the independent patent claims. This is described below with reference to the figures. The drawing shows Fig. 1 a Coriolis mass flow meter equipped with a method according to the invention, with electrical connections applied by a mechanical printing process, Fig. 2 a detailed view of the endpoints of the electrical connections applied by a machine printing process and Fig. 3 a meandering structure of conductor tracks applied by a machine printing technique as strain gauges.

[0025] The figures show a method 1 for equipping a Coriolis mass flow meter 2 with electrical connections 3 as well as a Coriolis mass flow meter instrumented in this way.

[0026] The in Fig. The Coriolis mass flow meter 2, shown in the most complete illustration, has various structural components. Two parallel measuring tubes 5a, 5b are shown, along with actuator mounts 6a, 6b attached to the measuring tubes 5a, 5b, and sensor mounts 7a-7d attached to the measuring tubes 5a, 5b. The two Coriolis measuring tubes 5a, 5b are held at the inlet and outlet ends by two gusset plates 8a, 8b. Coriolis mass flow meters 2 can, of course, have a multitude of other structural components, which are not shown here. However, this is not essential, as the principle presented here for equipping the Coriolis mass flow meter 2 with electrical connections 3 can easily be fully grasped and transferred to other structural components.

[0027] The Fig. The electrical connections 3 shown in 1 to 3 have all been applied to the measuring tubes 5a, 5b as structural parts of the Coriolis mass flow meter by a mechanical printing process - in this case by aerosol jet printing.

[0028] An electrically insulating coating, not shown separately, was applied to the measuring tubes 5a and 5b before the electrical connection 3 was applied. The electrical connections 3 were also coated with an electrically insulating top layer to protect the conductor tracks 3 and to ensure device safety. In the illustrated embodiments, the electrical connections are therefore electrically insulated and "packaged".

[0029] It is readily apparent that the very precise, repeatable and delicate realization of the electrical connections 3 by a machine printing process leads to a significantly less influence on the measuring tubes 5a, 5b than, for example, cables guided on the measuring tubes 5a, 5b which have been attached to the surface of the measuring tubes 5a, 5b with tape or adhesive dots.

[0030] In Fig. Figure 2 shows that the endpoints 9 of the electrical connections 3 have been designed with a flat surface, making them suitable for attaching wires – for example, by soldering. The wires, which are not shown here but can be attached to the endpoints 9, would then be led, for example, to the terminals of a vibration sensor mounted in the sensor mounts 7a, 7b.

[0031] In Fig. Figure 1 shows a perspective overview of how the electrical connections 3 run on the measuring tubes 5a, 5b. In the illustrated implementation, the electrical connections 3, applied by a machine printing process, run between the actuator mounts 6a, 6b and one of the sensor mounts 7a-7d. The endpoints of all electrical connections 3 are located adjacent to the junction plates 8a, 8b. From there, further contacting and, if necessary, wiring can be carried out.

[0032] Fig. Figure 3 shows that the electrical connections are printed as strain gauges, here in the form of meandering conductor tracks 10. With appropriate printing methods, it is also possible to print other functional components directly onto structural elements of the Coriolis mass flow meter 2. Reference symbol 1. Method for equipping a Coriolis mass flow meter with electrical connections 2 Coriolis mass flow meters 3 electrical connections 5 measuring tubes 6 Actuator recording 7 Sensor recording 8 node plate 9 Start and end points of electrical connections 10 meandering conductor tracks

Claims

[1] Method (1) for at least partially equipping a Coriolis mass flowmeter (2) with electrical connections (3), wherein the Coriolis mass flowmeter (2) has as structural parts at least one measuring tube (5a, 5b), at least one actuator receptacle (6a, 6b) attached to the measuring tube (5a, 5b) and at least one sensor receptacle (7a-7d) attached to the measuring tube (5a, 5b), characterized bythat the electrical connections (3) are applied to at least one of the structural parts of the Coriolis mass flowmeter (2) by a mechanical printing process, wherein the electrical connections (3) are printed onto the measuring tube (5a, 5b) as the at least one structural part, and that electrical connections (3) which serve to supply electrical power to electrical or electronic components of the Coriolis mass flowmeter (2) or to transmit signals are guided on the measuring tube (5a, 5b) via paths with minimal stretching or compression. [2] Method (1) according to claim 1, characterized by that an electrically insulating coating is applied to the structural part and the electrical connections (3) are printed onto the electrically insulating coating. [3] Method (1) according to claim 1 or 2, characterized bythat the printed electrical connections (3) are at least partially covered with an electrically insulating cover layer. [4] Method (1) according to one of claims 1 to 3, characterized by that the electrical connections (3) have end points (9) and that the end points (9) of the electrical connections (3) are designed to be flat, so that they can be used for fastening metallic conductors, in particular wires, by a joining technique, preferably by a thermal joining technique such as soldering or welding. [5] Method (1) according to claim 1, characterized by that the electrical connections (3) are applied to the measuring tube (5a, 5b) from a starting point (9) to an end point (9) by the mechanical printing process at least according to one of the following variants: - between the actuator holder (6a, 6b) and one of the sensor holders (7a - 7d), - if there are two sensor recordings (7a - 7d), between the two sensor recordings (7a - 7d), - if there is at least one node plate (8a, 8b) on the tailpipe side, between the sensor holder (7a - 7d) and the node plate (8a, 8b), - if there are two node plates (8a, 8b) on the tail pipe side, between the node plates (8a, 8b). [6] Method (1) according to one of claims 1 to 5, characterized by that the electrical connections at areas of interest are printed as strain gauges, in particular in the form of meandering conductor tracks (10). [7] Method (1) according to one of claims 1 to 6, characterized by that the electrical connections (3) at areas of interest are printed as thermal resistors. [8] Coriolis mass flowmeter (2) with structural parts, comprising at least one measuring tube (5a, 5b), at least one actuator receptacle (6a, 6b) attached to the measuring tube (5a, 5b) and at least one sensor receptacle (7a - 7d) attached to the measuring tube (5a, 5b), and with electrical connections (3) connected to the measuring tube (5a, 5b), characterized by that the electrical connections (3) are applied to at least one of the structural parts of the Coriolis mass flowmeter (2) by a mechanical printing process, wherein the electrical connections (3) are printed onto the measuring tube (5a, 5b) as the at least one structural part, and that electrical connections (3) which serve to supply electrical power to electrical or electronic components of the Coriolis mass flowmeter (2) or to transmit signals are guided on the measuring tube (5a, 5b) via paths with minimal stretching or compression. [9] Coriolis mass flow meter (2) according to claim 8, characterized by that the electrical connections (3) on the measuring tube (5a, 5b) run from a starting point (9) to an end point (9) at least according to one of the following variants: - between the actuator holder (6) and one of the sensor holders (7), - if there are two sensor recordings (7a - 7d), between the two sensor recordings (7a - 7d), - if there is at least one node plate (8) on the tailpipe side, between the sensor holder (7a - 7d) and the node plate (8), - if there are two node plates (8a, 8b) on the tail pipe side, between the node plates (8a, 8b).

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