METHOD FOR PRODUCING A MEASUREMENT TUBE ASSEMBLY FOR A CORIOLIS FLOW METER

Abstract

A method for producing a measurement tube assembly for a Coriolis flow meter includes: providing a core assembly and a mold, which define a cavity therebetween, the core assembly a core that includes a core body of a first material; filling the cavity with a second material to form a measurement tube body of the measurement tube assembly, the second material having a higher melting temperature than the first material; separating the mold and the core assembly from the measurement tube assembly melting the at a melting temperature that is below the melting temperature of the second material and above the melting temperature of the first material. The present disclosure further includes a Coriolis flow meter and to a use of a lost-core method to produce a measurement tube assembly.

Claims

1-11. (canceled)

12. A method for producing a measurement tube assembly for a Coriolis flow meter, the method comprising: providing a core assembly and a mold configured to define a cavity between the core assembly and the mold, wherein the core assembly comprising at least one core, the at least one core comprising a core body, comprising a first material having a first melting temperature; filling the cavity with a second material as to form a measurement tube body of a measurement tube of the measurement tube assembly, the second material having a second melting temperature that is higher than the first melting temperature; separating the mold and the core assembly from the measurement tube assembly, wherein the core assembly is separated by melting of the at least one core of the core assembly at a process melting temperature that is below the melting temperature of the second material and above the melting temperature of the first material.

13. The method of claim 12, wherein the at least one core includes a bend.

14. The method of claim 13, wherein the at least core includes at least two regions that run parallel to one another, and wherein the bend is between two of the at least two regions.

15. The method of claim 12, wherein the mold has at least one receptacle in which a magnetic device is inserted, wherein the magnetic device is overmolded with the second material when the cavity is filled such that the magnetic device is secured in a form-fitting manner in the formed measurement tube body.

16. The method of claim 12, wherein the mold includes at least one bulge configured to form a recess in the formed measurement tube body, and wherein the recess is configured to receive at least one magnetic device.

17. The method of claim 12, wherein: the at least one core of the core assembly comprises exactly two cores; the two cores and the mold define a first cavity and a second cavity configured to form two measurement tubes; the mold defines at least a third cavity that connects the first cavity and the second cavity; and a coupler element body, which connects the two measurement tubes to each other, is formed when the at least third cavity is filled.

18. The method of claim 17, wherein a first support body is arranged in the third cavity, the first support body configured to increase the mechanical strength of the coupler element body, and wherein the first support body comprises a third material having a third melting temperature that is higher than the first melting temperature.

19. The method of claim 12, wherein: the at least one core of the core assembly comprises exactly two cores; the two cores and the mold define a first cavity and a second cavity configured to form two measurement tubes; the mold and the cores define a fourth cavity; the fourth cavity is intersected in each case twice by the two cores; and a decoupling body, which connects the two measurement tubes to each other, is formed when the fourth cavity is filled.

20. The method of claim 19, wherein a second support body is arranged in the fourth cavity, the second support body configured to increase the mechanical strength of the decoupling body, and wherein the second support body comprises a fourth material having a fourth melting temperature that is higher than the first melting temperature.

21. A Coriolis flow meter, comprising: a measurement tube assembly; at least one vibration exciter which is designed to excite the measurement tube assembly to vibrate; and at least one vibration sensor which is designed to detect the deflection of the vibrations of the measurement tube assembly, wherein the measurement tube assembly is produced by the method according to claim 12.

22. A method for producing a measurement tube assembly for a Coriolis flow meter, the method comprising: using a lost-core method in an injection molding process to produce the measurement tube assembly.

Description

[0053] The invention is explained in greater detail with reference to the following figures. The following are shown:

[0054] FIG. 1: an embodiment of the core assembly according to the invention;

[0055] FIG. 2: a longitudinal section through an embodiment of the mold according to the invention;

[0056] FIG. 3: a cutout of a core assembly inserted into the mold;

[0057] FIG. 4: a further embodiment of the core assembly according to the invention, with a support body;

[0058] FIG. 5: an encapsulated core assembly;

[0059] FIG. 6: a measurement tube assembly with the core assembly melted out;

[0060] FIG. 7: a measurement tube assembly with attached magnets;

[0061] FIG. 8: three views of a Coriolis flow meter according to the invention.

[0062] FIG. 1 shows an embodiment of a core assembly 1 which, together with the mold, is used to form a cavity or a hollow space which defines the shape and surface structure of the manufactured measurement tube assembly. According to the illustrated embodiment, the core assembly 1 has two cores 4.1, 4.2, which are connected to one another via a connecting body 29. The connecting body is used to arrange and fix the core assembly 1 as easily as possible in the mold in a position predetermined for this purpose. The connecting body 19 can be connected monolithically to the core assembly 1, or can be attached in a form-fitting and/or force-fitting manner. Both cores 4.1, 4.2 each have two sections 12.1, 12.2, in which the respective longitudinal axes of the core run parallel to one another, and a bend 11, which is arranged between the two sections 12.1, 12.2. Thus, the component produced by injection molding also has a curve. The channel for guiding the flowable medium in the measurement tube is essentially U-shaped. The core body 5 has a first material 9 which has a lower melting temperature than the melting temperature of the second material from which the measurement tube body is formed. The core assembly 1 has two mirror planes, which are perpendicular to one another and divide the core assembly 1 into two parts. A first mirror plane runs between the two cores. The second mirror plane intersects the two cores 4.1, 4.2 in the curved region, wherein the longitudinal axes of the two sections 12.1, 12.2 are spaced equally far from the second mirror plane. The cores 4.1, 4.2 are partially cylindrical, or have a circular cross-sectional area. The cores 4.1, 4.2 can also each have a multi-part design, i.e., consist of multiple individual parts which form the respective core 4.1, 4.2 when put together.

[0063] FIG. 2 shows a longitudinal section through an embodiment of the mold 2 into which the core assembly is inserted and which, together with the core assembly, forms a cavity for casting with flowable plastic and forming a measurement tube assembly. The mold can have a multi-part design. The mold 2 comprises a channel which has two regions 13.1, 13.2 which are each formed parallel to one another and are connected to one another by means of a curve. According to the depicted embodiment, in the two regions 13.1, 13.2, receptacles 14 for magnets of the magnetic device 15 are arranged in the mold 2. The magnets are attached in the receptacle in such a way that they are connected to the respective measurement tube bodies in a form-fitting manner when the measurement tube assembly is formed. The magnets of the magnetic device 15 are components of the vibration sensors and of the vibration exciter.

[0064] The mold can have a receptacle for the connecting body of the core assembly, which receptacle is used to fix the core assembly in a predetermined position.

[0065] FIG. 3 shows a detail of the core assembly 1 from FIG. 1, arranged in the mold 2 of FIG. 2. A cavity 3 is formed in the process which, later in the course of the method, is filled with the casting compound, in particular the liquid plastic, and defines the shape of the measurement tube assembly. The core assembly 1 and the mold 2 form a first cavity 19 and a second cavity 20. After the third cavity 21 has been filled with a casting compound, and the casting compound has cured, the measurement tube body is formed in the first cavity 19 and in the second cavity 20. Six first support bodies 23 are attached to the core assembly 1 and, with the mold 2, each form a third cavity 21. Three of the first support bodies 23 are attached in the inlet section, and three of the first support bodies 23 are attached in the outlet section, of the core assembly 1. The first support bodies 23 connect the cores to one another in the respective sections. The first support body 23 has a fourth material 28 which has a melting temperature which is higher than the melting temperature of the first material 9 of the core body 5 of the core assembly 1. After the third cavity 21 has been filled with a casting compound, and the casting compound has cured, a coupler element with a coupler element body is formed in the third cavity 21.

[0066] A second support body 27, which has a fourth material 28 having a melting temperature which is higher than the melting temperature of the first material 9, is also attached to the core assembly 1. A fourth cavity 25 is formed between the second support body 27 and the mold 2, and forms a decoupling body when filled.

[0067] FIG. 4 shows a further embodiment of the core assembly 1, which has at least all the essential features of the embodiment shown in FIG. 1. In addition, a second support body 27 is attached to the core assembly 1. The second support body 27 comprises a fourth material 28 which has a higher melting temperature than the melting temperature of the first material 9. The second support body 27 is used to connect the two measurement tubes of the measurement tube assembly to one another, and thus mechanically couple them from the surroundings. The second support body 27 connects the respective inlet sections of the cores to one another and to the outlet sections of the cores.

[0068] FIG. 5 shows an overmolded and demolded core assembly 1 of FIG. 4. The plastic injected in liquid form forms the measurement tube assembly 8 with the coupler element body 22. The mold has been removed. The measurement tube assembly 8 has two measurement tubes 7.1, 7.2, each of which is formed from a second material 10. The melting temperature of the second material 10 is higher than the melting temperature of the first material. The first support body 23 is integrated into the coupler element body 22 and is at least partially enclosed by the cured casting compound. Furthermore, the measurement tube assembly 8 has a decoupling body 26, which comprises the second support body.

[0069] FIG. 6 shows the measurement tube assembly 8 with the core assembly melted out. The measurement tube assembly 8 comprises a measurement tube body 6. The measurement tube body 6 has receptacles for the magnetic device. The two measurement tubes are connected to one another via two coupler elements 22, which are arranged in the inlet and outlet regions. The coupler elements 22 assume the shape of the third cavity. s

[0070] FIG. 7 shows the measurement tube assembly 8 of FIG. 6 with an attached magnetic device 15. The magnets of the magnetic device are arranged in the receptacles and are connected to the measurement tube body in an integrally-bonded and/or form-fitting manner.

[0071] The embodiment of a Coriolis flow meter according to the invention shown in FIG. 8 comprises a measurement tube assembly which is produced by means of the method according to the invention and comprises two, parallel, curved measurement tubes 110a, 110b, which extend between an inlet-side collector 120a and an outlet-side collector 120b, and are fixedly connected thereto. Extending between the collectors 120a, 120b is a solid carrier tube or carrier body 124 fixedly connected to the two collectors, thereby rigidly coupling the collectors 120a, 120b to each other. The carrier tube 124 has, on its upper side, openings 125a, 125b, through which the measurement tubes 110a, 110b run from the collectors out of the carrier tube 124 and back again. The measurement tubes 110a, 110b are connected on the inlet side and outlet side to two coupler elements 132a, 134a, 132b, 134b in each case, said coupler elements being produced by the method according to the invention, wherein the coupler elements each have a continuous hole 30 between the measurement tubes, said hole being used to reduce the stiffness in the Y-direction of the geometric center in the second region between the two measurement tubes. The coupler elements 132a, 132b, 134a, 134b define vibration nodes for the measurement tubes. Between the inner coupler elements 132a, 132b, the measurement tubes 110a, 110b can vibrate freely, so that the vibration properties of the vibrator formed by the measurement tubes 110a, 110b, in particular natural frequencies of vibration modes of the vibrator, are substantially also determined by the position of the inner coupler elements. The measurement tubes are formed from glass or plastic.

[0072] For exciting vibrations relative to the longitudinal direction or the Z-axis in the center of the flow meter 100, an exciter assembly 140, e.g., an inductive exciter assembly, is provided between the measurement tubes, said exciter assembly comprising, for example, a plunger coil on one measurement tube and, opposite the plunger body, a measurement tube or a magnet on the measurement tube, and a semiconductor coil on the carrier tube. For detecting the vibrations of the measurement tubes, a first sensor assembly 142a and a second sensor assembly 142b are provided in the longitudinal direction, symmetrically with respect to the exciter assembly 140, and are each designed as an inductive assembly with a plunger coil on one tube and a plunger body on the other tube. Details are known to the person skilled in the art and need not be explained here.

[0073] The collectors 120a, 120b have end flanges 122a, 122b, by means of which the meter can be installed in a pipeline. Through central openings 123b in the flanges, a mass flow can be conducted through the meter 100, in particular its pipelines 110a, 110b, in order to measure the mass flow.

[0074] The measurement tubes 110a, 110b are connected on the inlet side and outlet side to two coupler elements 132a, 134a, 132b, 134b in each case, wherein the coupler elements each have a hole 30 between the measurement tubes.

LIST OF REFERENCE SIGNS

[0075] 1 Core assembly 1 [0076] 2 Mold 2 [0077] 3 Cavity 3 [0078] 4 Core 4 [0079] 5 Core body 5 [0080] 6 Measurement tube body 6 [0081] 7 Measurement tube 7 [0082] 8 Measurement tube assembly 8 [0083] 9 First material 9 [0084] 10 Second material 10 [0085] 11 Bend 11 [0086] 12 Region 12 [0087] 13 Region 13 [0088] 14 Receptacle 14 [0089] 15 Magnetic device 15 [0090] 17 Recess [0091] 19 First cavity 19 [0092] 20 Second cavity 20 [0093] 21 Third cavity 21 [0094] 22 Coupler element 22 [0095] 23 First support body 23 [0096] 24 Third material 24 [0097] 25 Fourth cavity 25 [0098] 26 Decoupling body 26 [0099] 27 Second support body 27 [0100] 28 Fourth material 28 [0101] 29 Connecting body 29 [0102] 110a Curved measurement tube [0103] 110b Curved measurement tube [0104] 120a Inlet-side collector [0105] 120b Outlet-side collector [0106] 122a End flange [0107] 122b End flange [0108] 123a Inlet [0109] 123b Outlet [0110] 124 Carrier tube [0111] 125a Opening in upper side [0112] 125b Opening in upper side [0113] 132a Coupler element [0114] 132b Coupler element [0115] 134a Coupler element [0116] 134b Coupler element [0117] 140 Vibration exciter [0118] 142a Vibration sensor [0119] 142b Vibration sensor [0120] 146 Tuning opening