US20050268687A1

US20050268687A1 - Manufacturing a curved measuring tube for a vibratory measurement pickup

Info

Publication number: US20050268687A1
Application number: US11/125,160
Authority: US
Inventors: Rainer Lorenz
Original assignee: Endress and Hauser Flowtec AG
Current assignee: Endress and Hauser Flowtec AG
Priority date: 2004-05-10
Filing date: 2005-05-10
Publication date: 2005-12-08

Abstract

For manufacturing a measuring tube from a tube section, first a solid forming core serving during the bending for stabilizing the cross section of the tube section is formed within the lumen of the tube section from a first fill substance and a second fill substance included therein. The first fill substance is a solidified liquid, especially wax, fat or water, having a melting temperature lower than a melting temperature of the tube section, while the second fill substance is, at least in a normal condition, an essentially pourable, especially grainy and/or powdered, loose material, especially granulated material, sand or the like, having a melting temperature which is higher than the melting temperature of the liquid. Following the creating of the forming core, the tube section is bent by the introduction of a bending force acting at least sectionally externally on the tube section. Finally, the forming core is desolidified within the lumen of the bent tube section by effecting the melting of the fill substance in the form of solidified liquid within the bent tube section.

Description

The invention concerns a method for bending at least one measuring tube of a vibratory measurement pickup, esp. a Coriolis mass flow measurement pickup.
Vibration-type measurement pickups, for example Coriolis mass flow measurement pickups, Coriolis mass flow/density measurement pickups and/or viscosity/density measurement pickups, etc., can be divided into essentially two classes on the basis of the form of the measuring tube used, namely measurement pickups with at least one straight measuring tube and those with at least one curved measuring tube, curved at least sectionally with arcuate shape. The measuring tubes of concern in this invention belong to the latter class. The structure as well as the functioning and application of such measurement pickups, which are, per se, long known to those skilled in the art, are also, for example, described in detail in DE-A 43 27 052, U.S. Pat. No. 6,711,958, U.S. Pat. No. 5,394,758, U.S. Pat. No. 5,796,011, U.S. Pat. No. 6,308,580 or WO-A 03 029 761.
In the case of measurement pickups of the described type, particularly easy to produce have been, above all, curved measuring tubes that are bent such that the bend line of any particular tube lies essentially in a single, imaginary, tube plane, and its bend line is, as viewed transversely to the longitudinal axis, essentially “open”, thus free from cutting back. Such measuring tubes can e.g. be bent essentially U-, V- or S-shaped as shown in DE-A 43 27 052, U.S. Pat. No. 6,711,958, U.S. Pat. No. 5,394,758, U.S. Pat. No. 5,796,011, U.S. Pat. No. 6,591,656 or WO-A 03 029 761, and also with trapezoidal or rectangular shape as shown in U.S. Pat. No. 6,308,580. Measuring tubes bent in a plane are comparatively simple to manufacture, because they can be brought to the desired form very easily, for instance using a two-piece metal-forming press mold charged with a straight length of tubular stock as the starting tube section. Usually the tube sections to be bent are equipped with a forming core which is as incompressible as possible, in order to make sure that the shape of the cross-section of the tube section, usually an appropriate circular cross-section, comes through the bending as unchanged as possible.
A process very well suited for the production of such measuring tubes is shown in U.S. Pat. No. 6,591,656, for example. In that case, of concern particularly is a process to press bend a measuring tube for a Coriolis mass flow measurement pickup into a desired measuring tube form starting with an essentially straight tube section of predetermined length and using a two-piece press mold matched to the measuring tube and the desired measuring tube shape. In that process, a flexible, metal-spiral spring is inserted into the tube section and fastened in a first end of the tube section, which end is then sealed. The spring has a maximum outer diameter which is smaller than the inner diameter of the tube section. Subsequently, the tube section is filled with a liquid and this is then allowed to completely solidify, whereby a solid, forming core is created in the lumen of the tube section. Afterwards, the tube section is bent by introduction of a bending force which acts externally at least sectionally on the tube section. Finally, the solidified liquid is allowed to melt again, and, thereafter, the spiral spring (which served as a support body for the solidified liquid) and the melted liquid are removed from the bent tube section. In the disclosed method, the bending of the tube section occurs in an especially easy way by placing the tube section, equipped with the forming core, within the opened press mold, and then the press mold is closed to accomplish the forming of the tube section. Another process to bend such measuring tubes, involving a forming core of solidified liquid serving for stabilizing the tube section, is, for example, also shown in U.S. Pat. No. 2,334,661.
The combined use of easily fusible liquid with a support body supporting such allows, on the one hand, a comparatively simple and, on the other hand, a highly exact bending of measuring tubes for measurement pickups like those described here. The high accuracy of this method can be attributed, as for example also discussed in U.S. Pat. No. 6,591,656, among other things to the fact that the solidified liquid as filler does contribute the principal part of this high accuracy, that, however, the support body, which has a maximum diameter that is smaller than the inner diameter of the measuring tube, carries a thin layer of solidified liquid that lies between the inner wall of the measuring tube and the support body, and that this contributes the remainder of the high accuracy.
However, although the support body has a maximum diameter which is smaller than the inner diameter of the measuring tube, and thus the removal of the support body from the measuring tube after bending and after the solidified liquid becomes liquid again is possible without further ado, it has been found that the extraction of the support body occasionally can cause slight damaging of the internal surface of the bent measuring tube, for example through scratching, esp. in the case of bending radii small in comparison to the diameter of the measuring tube and/or in the case of long, arcuate segments. Beyond that, light imprints can occasionally be observed in the internal surface, esp. if the support body is constructed in the form of a metallic, spiral spring. Such damages to the surface are generally very insignificant and are, therefore, mostly tolerable. Nevertheless, many applications require a very smooth, undamaged, internal surface of the measuring tube, for example in the foodstuffs industry with its usually very high hygienic requirements. In addition, substantial difficulties can arise also in the case of very small diameters in the threading of the then necessarily likewise very thinly implemented support body into the tube section.
An object of the invention is, therefore, to improve the manufacture of the described type of measuring tube such that, especially while maintaining the high accuracy in producing the measuring tube achieved through the above-described press bending, damage or injury to the internal surface when using a support body embedded in solidified liquid, esp. also in the case of small bending radii and/or long, arcuate segments, can be largely avoided.
For achieving the object, the invention provides a method for manufacturing a bent measuring tube for a vibratory measurement pickup, esp. a Coriolis mass flow measurement pickup, into a desired form from a tube section of predetermined cross section and lumen, which method includes the following steps:

- Forming, within the lumen of the tube section to be bent, a solid forming core of a first fill substance and a second fill substance included therein, the forming core serving to stabilize the cross section of the tube section during bending;
- bending the tube section through introduction of a bending force that acts at least sectionally externally on the tube section; and
- desolidifying the forming core within the lumen of the bent tube section;
- wherein a solidified liquid, esp. wax, fat or water, that has a melting temperature lower than the melting temperature of the tube section, serves as the first fill substance, and an at least normally essentially pourable, esp. grainy and/or powdered, loose material, esp. granular material, sand or the like, having a melting temperature higher than the melting temperature of the liquid, serves as the second fill substance; and
- wherein the step of desolidifying the forming core within the lumen of the bent tube section includes a step of melting the first fill substance situated in the form of solidified liquid within the bent tube section.

According to a first embodiment of the invention, the step of forming the forming core within the lumen of the tube section includes the following steps:

- Introducing at least a part of the first fill substance in the form of molten liquid, as well as at least a part of the second fill substance, into the lumen of the tube section; and
- causing the first fill substance, in the form of molten liquid, to solidify within the lumen of the tube section.

According to a second embodiment of the invention, the first fill substance in the form of liquid is poured into the tube section for creating the forming core within the lumen of the tube section.
According to a third embodiment of the invention, the method includes, further, a step of liquid-tight sealing at least one end of the tube section.
According to a fourth embodiment of the invention, a momentarily pourable, loose material is used as the second fill substance, and the step of introducing second fill substance includes a step of filling pourable, especially grainy and/or powdered, loose material into the lumen of the tube section.
According to a fifth embodiment of the invention, the filling of at least a part of the first fill substance into the lumen of the tube section occurs before and/or during the filling of the second fill substance into the lumen of the tube section.
According to a sixth embodiment of the invention, the filling of at least a part of the second fill substance into the lumen of the tube section occurs before and/or during the filling of the first fill substance into the lumen of the tube section.
According to a seventh embodiment of the invention, the method includes, further, a step of densifying the filled second fill substance within the lumen of the tube section, esp. by shaking and/or tamping.
According to an eighth embodiment of the invention, the method includes, further, a step for removing the molten first fill substance from the lumen of the bent tube section.
According to a ninth embodiment of the invention, liquid is allowed to flow out of the bent tube section to remove the melted first fill substance from the lumen of the bent tube section.
According to a tenth embodiment of the invention, the step of desolidifying the forming core within the lumen of the bent tube section includes a step of loosening the second material contained in the lumen of the bent tube section.
According to an eleventh embodiment of the invention, the method includes, further, a step for removing loose, esp. pourable, second fill substance from the bent tube section.
According to a twelfth embodiment of the invention, the step of removing the second fill substance from the bent tube section includes a step of allowing the loose material to flow from the bent tube section.
According to a thirteenth embodiment of the invention, the second fill substance is used in a 9:1 ratio, or more, with respect to the first fill substance.
According to a fourteenth embodiment of the invention, the first fill substance is a liquid that solidifies at a temperature less than 100° C., especially at a temperature around 0° C.
According to a fifteenth embodiment of the invention, at least part of the second fill substance is comprised of a granular material, especially one having spherical particles.
According to a sixteenth embodiment of the invention, at least part of the second fill substance is comprised of a powder.
According to a seventeenth embodiment of the invention, the second fill substance is at least partially mineral.
According to an eighteenth embodiment of the invention, the second fill substance is at least partially organic.
According to a nineteenth embodiment of the invention, the second fill substance is at least partially metallic.
According to a twentieth embodiment of the invention, at least part of the first fill substance is comprised of water.
According to a twenty-first embodiment of the invention, at least part of the first fill substance is comprised of wax, oil or fat.
According to a further development of the invention, the method is implemented using a press mold matched to the desired form of the measuring tube to be manufactured and having a punch and a cavity, wherein the step of bending the tube section through introduction of a bending force that acts at least sectionally externally on the tube section includes the following steps:

- Inserting the tube section, equipped with the forming core, into the opened press mold and positioning it between punch and cavity; and
- closing the press mold and bending the tube section by means of relative motion of punch and cavity towards one another.

According to an embodiment of this further development of the invention, the method includes the following further steps:

- Opening the press mold after the bending of the tube section; and
- removing the bent tube section from the opened press mold.

A basic idea of the invention is to create, within the lumen of the tube section to be bent, an optimally adapted, but also easily removable, forming core, so that not only the liquid but also the filler stabilizing the solidified liquid during the bending are made flowable, especially pourable, before and after the bending, while both form a very firm composite during the bending.
An advantage of the invention is that, among other things, the forming core formed in-situ is constructed very solidly. Equally as well, it can be easily brought into the tube section and also again easily removed from the finished, bent measuring tube without endangering the internal surface. A further advantage of the invention is, in addition, that, by the filler serving for supporting the solidified liquid, a forming core can be created which also has a very dimensionally stable cross section during bending despite the use of ice, which has a quite significant tendency to flow as a solidified liquid.
The invention will now be described in detail on the basis of the figures of the drawing which show the sequentially following steps of a method as an example of an embodiment. Functionally equal parts are provided with the same reference symbols in different figures, but are repeated in following figures only if it appears meaningful.
FIG. 1 shows, in side view, a tube section to be bent,
FIG. 2 shows the tube section of FIG. 1 in a side view, with one end sealed to be fluid-tight,
FIG. 3 shows the tube section of FIG. 1 in a side view, with a fill substance of pourable loose material in the process of being funneled in,
FIG. 4 shows the tube section of FIG. 3 in a side view, with a further fill substance in the form of liquid in the process of being poured in,
FIG. 5 shows the tube section of FIG. 4 in a side view, in whose lumen a solid forming core has been created from the fill substances of FIGS. 3 and 4,
FIG. 6 shows a side view of a bent tube section manufactured from the tube section of FIG. 1, from which the de-solidified forming core of FIG. 5 is being removed by the outflowing of the fill substances of FIGS. 3 and 4,
FIG. 7 shows an opened press mold schematically in side view,
FIG. 8 shows the opened press mold of FIG. 7 schematically in side view, into which a tube section of FIG. 5 has been placed,
FIG. 9 shows the closed press mold of FIG. 8 schematically in side view, with a tube section of FIG. 6 manufactured by the closing of the same, and
FIG. 10 shows schematically in side view the press mold opened again, for removal of the bent tube section.
FIG. 11 a vibration-type measurement pickup employing a bent tube section of FIG. 6 for a measuring tube.
FIGS. 1 to 5 each show, in sectional side view, a tube section 1′, especially a straight one, of predetermined, particularly circular, cross section and lumen. Tube section 1′ is to be transformed into a bent tube section 1″ of predetermined spatial form through suitable introduction of a bending force acting thereon at least sectionally externally. The bent tube section 1″ again, in turn, serves later, as shown in FIG. 11, as a measuring tube 1 of a vibratory measurement pickup 10, for example a Coriolis mass flow measurement pickup.
Before beginning the actual deformation process, the tube section 1′ can, for example, be cut with a desired length L from a piece of tube stock (not shown). The length L of the tube section 1′ comes simply from the desired length of the bent tube section 1″. The tube section 1′ has a predetermined inner diameter d1 and can be manufactured from material normally used for measuring tubes of the described kind, e.g. stainless steel, titanium, tantalum, zirconium, or the like.
In order to prevent, as much as possible, an undesired deformation of the cross section during the bending of the tube section 1′, a forming core 2 is used. The forming core 2 essentially fills the lumen of the tube section 1′ and serves to stabilize its cross section. The forming core 2 is formed before the bending, directly within the lumen, thus in-situ, or at least the final steps of its formation are finished there. Forming core 2 is composed of a first fill substance 21 and a second fill substance 22 included therein. According to the invention, serving in such case as the first fill substance 21 is a solidified liquid, especially wax, fat or water, having a melting temperature lower than a melting temperature of the tube section 1′. Additionally, used as the second fill substance 22 is a material which, at least in a normal state, is in the form of an essentially pourable, especially grainy and/or powdered, loose material 22′, having a melting temperature higher than the melting temperature of the liquid used as the first fill substance 21. Examples of fill substance 22 are granular materials, especially such as exhibit a spherical particle shape, for instance sand, especially gravel, and/or the like. The fill substance 22 can be a mineral, organic and/or metallic material. In keeping with the application, the forming core 2 can, consequently, be formed, very simply, by introducing the fill substance 21 into the lumen of the tube section while it is at least partially in a liquid state, and then, following introduction of a sufficient amount of the second fill substance 22, the substance 21 is solidified as completely as possible, for example in a suitable refrigerator or freezer. The fill substance 21 and the fill substance 22 can, for example, be charged into the lumen simultaneously, one after the other, or alternatingly. In the last case, it can even be useful to solidify a part of the liquid used as fill substance 21, before the charging of further amounts thereof and/or further amounts of the second fill substance 22. In case required, the fill substance 22 filled into the tube section 1′, momentarily as loose material 22′, can be further densified, for instance by appropriate tamping and/or mechanical shaking, for increasing the strength of the resulting forming core 2. The actually required amounts of the first and second fill substances 21, 22 for the formation of a given forming core 2 can be easily determined, for instance experimentally, taking into consideration possible volume fluctuations associated with the cooling thereof. According to an embodiment of the invention, the second fill substance 22 is used in a ratio of 9:1 to the first fill substance 21.
For creating the forming core 2, the tube section 1′ of the example of an embodiment illustrated here is first sealed at an end to the escape of liquid by means of a closure, for example a simple stopper 4, and then placed upwards, or hung up, with the sealed end down; compare FIG. 2.
Subsequently, according to an embodiment of the method of the invention, on the one hand, the fill substance 21, momentarily in the form of molten, especially low viscosity, liquid 21′, and, on the other hand, the second fill substance 22, momentarily in the form of at least partially pourable, especially grainy and/or powdered, loose material 22′, are introduced into the lumen of the tube section 1′ that is to be bent. The charging of the two fill substances 21, 22 can, as indicated in FIGS. 3 and 4, be done, in simple manner, by the filling of the pourable materials 21′, 22′ through the upper, unsealed end of the vertically positioned tube section 1′.
According to another embodiment of the method of the invention, at least a part of the fill substance 21 together with a part of the fill substance 22 are first processed outside of the tube section 1′, at least to a solid inner core, which, once it has been prepared, is inserted into the lumen of the tube section 1′ for the forming of the actual forming core 2. For preparing the inner core, a casting mold appropriately sized considering the size of the lumen can be used, for instance a casting mold composed of two, assembled, half-shells. Following filling of the casting mold with the two starting materials, fill substance 21 and fill substance 22, the mold is, in turn, placed in an environment having a temperature appropriate for solidifying the liquid.
After the lumen of the tube section 1′ has been sufficiently filled with, at least partially liquid, fill substance 21 and with fill substance 22, as schematically shown in FIG. 5, the still liquid fill substance 21 is caused to solidify in the lumen of the tube section 1′. Finally, the tube section 1′ is transformed in the desired manner by appropriate bending.
In order to enable a simple removal of the forming core 2 from the lumen of the finally bent tube section 1″, the forming core is, according to the invention, then desolidified as much as possible, especially essentially completely, while still inside the lumen of the bent tube section 1″. This is accomplished by causing a predominant part 6 f the first fill substance 21 to remelt. As a result, in the same way, also the fill substance 22 previously included therein, is again loosened, especially made again pourable, whereby the support not only desolidifies, but it becomes, in fact, largely flowable.
Following the liquefying of the fill substance 21, this, together with the again loose, especially again flowable, material of fill substance 22, can then be removed from the lumen of the now bent tube section 1″, simply by allowing it to flow, especially pour, out, as is illustrated in FIG. 6. For the first fill substance 21, practically any liquid, whose solidification temperature is a few 100° C. lower than the melting temperature of the material of the tube section 1′ and of the material of the fill substance 22, is suitable. Thus, metals with such lower melting points, such as e.g. bismuth or Woods metal, but even low-viscosity, aqueous solutions, which solidify at a temperature less than 100° C., especially, however, at a temperature around 0° C., for example water itself, or organic compounds, such as e.g. waxes, oils, fats or the like, can be used as the fill substance 21. The use especially of water for preparing the forming core 2 has, on the one hand, the advantage that such is very easy to obtain and is, at the same time, quite favorable as to cost. Along with its easy availability, water as fill substance 21, moreover, reduces, to a considerable degree, the effort required for cleaning the inner surface of the bent tube section.
According to a further development of the invention, the tube section 1′ is bent by means of a press mold 3 matched to the shape desired for the finished measuring tube 1; a press mold 3 suitable for this further development of the invention is shown schematically in FIGS. 7 to 10 for the different steps of the method. The press mold 3 shown opened in FIG. 7 includes an upper part 31 with a punch 311 and a lower part 32 with a cavity 321 formed as counterpart to the punch 311. Punch 311 and cavity 321 are matched to the desired shape of the finished, bent, tube section 1″, as well as to its outer diameter. For this purpose, both the punch 311 and the cavity are provided with grooves, with the groove of the punch having a contour essentially corresponding to the upper side of the finished, bent tube section 1″ and the groove of the cavity 321 a contour essentially corresponding to the lower side of the finished, bent, tube section 1″. Correspondingly, the two grooves have cross sections in the form of semicircles, whose diameter equals the outer diameter of the tube section 1. In this way, the cross section of the groove of the punch 311 complements the cross section of the groove of the cavity 321, when the press mold 3 is completely closed, to complete a circular cross section. The lower part additionally includes a stop 33 for the tube section 1′ that is to be bent.
In the example of an embodiment shown in FIGS. 7 to 10, the contours of punch 311 and cavity 321, as well as the two grooves, are formed such that the finished, bent tube section 1″ is curved essentially into a U-, or V-, shape. Additionally, the grooves of the punch 311 and cavity 321 are formed and coordinated such that both an imagined bending line of the finished, bent, tube section 1″ and a longitudinal axis imaginarily connecting its two ends, both lie in a common plane.
In the case of this further development of the method, for the bending of the tube section 1′, the same is placed, after being equipped with the forming core 2, into the opened press mold 3, and, thus, positioned between punch 311 and cavity 321, as shown schematically in FIG. 8. Thereafter, the press mold is closed sufficiently, by suitable, relative movement of punch 321 and cavity 311 together—here by travel of the punch 311 alone—and then held closed for a sufficient duration, that the tube section 1′ becomes formed in the desired manner. FIG. 9 shows the closed press mold 3 of FIG. 8, with the correspondingly bent tube section 1″ obtained by the closing of the same. It is evident that, as already mentioned, the bent tube section 1″ becomes shorter, as a result of the bending, than the length L of the straight tube section 1.
Finally, FIG. 10 schematically illustrates the again opened press mold 3, from which the bent tube section 1″ is in the process of being removed. The forming core 2 contained therein, possibly already partially shattered by the bending, is removed, this being indicated in the drawing by the rightwards facing arrow. The bent tube section 1″ can be used practically immediately following removal from the press mold 3 as a measuring tube 1 for a vibration-type measurement pick 10, especially also without complicated further processing.

Claims

1-25. (canceled)

26. A method for manufacturing a bent measuring tube for a vibration-type measurement pickup, esp. a Coriolis mass flow measurement pickup, into a desired form using a tube section of predetermined cross section and lumen, which method comprises the steps of:

forming, within the lumen of the tube section to be bent, a solid forming core of a first fill substance and a second fill substance included therein, said forming core serving to stabilize the cross section of the tube section during bending;

bending the tube section through introduction of a bending force that acts at least sectionally externally on the tube section; and

desolidifying the forming core within the lumen of the bent tube section, wherein:

a solidified liquid, esp. wax, fat or water, that has a melting temperature lower than the melting temperature of the tube section, serves as the first fill substance, and an at least normally essentially pourable, esp. grainy and/or powdered, loose material, having a melting temperature that is higher than the melting temperature of the liquid, serves as the second fill substance; and

the step of desolidifying the forming core within the lumen of the bent tube section includes a step of melting the first fill substance situated in the form of solidified liquid within the bent tube section.

27. The method as claimed in claim 26, wherein:

the step of forming the forming core within the lumen of the tube section includes the following steps: introducing at least a part of the first fill substance in the form of molten liquid, as well as at least a part of the second fill substance, into the lumen of the tube section; and causing the first fill substance, in the form of molten liquid, to solidify within the lumen of the tube section.

28. The method as claimed in claim 26, wherein:

the first fill substance in the form of liquid is poured into the tube section for the purpose of forming the forming core within the lumen of the tube section.

29. The method as claimed in claim 26, further comprising the step of:

liquid-tight sealing at least one end of the tube section.

30. The method as claimed in claim 26, wherein:

a momentarily pourable, loose material is used as the second fill substance; and

the step of introducing a second fill substance includes a step of filling pourable, especially grainy and/or powdered, loose material into the lumen of the tube section.

31. The method as claimed in claim 30, wherein:

the filling at least of a part of the first fill substance into the lumen of the tube section occurs before and/or during the filling of the second fill substance into the lumen of the tube section.

32. The method as claimed in claim 30, wherein:

the filling of at least a part of the second fill substance into the lumen of the tube section occurs before and/or during the filling of the first fill substance into the lumen of the tube section.

33. The method as claimed in claim 30, further comprising the step of:

densifying the filled second fill substance within the lumen of the tube section, esp. by shaking and/or tamping.

34. The method as claimed in claim 26, further comprising the step of:

removing the molten first fill substance from the lumen of the bent tube section.

35. The method as claimed in claim 26, wherein:

liquid is allowed to flow out of the bent tube section to remove the melted first fill substance from the lumen of the bent tube section.

36. The method as claimed in claim 26, wherein:

the step of desolidifying the forming core within the lumen of the bent tube section includes a step of loosening the second fill substance contained in the lumen of the bent tube section.

37. The method as claimed in claim 36, further including the step of:

removing loose, esp. pourable, second fill substance from the bent tube section.

38. The method as claimed in claim 26, wherein;

the step of removing the second fill substance from the bent tube section includes a step of allowing loose material to flow from the bent tube section.

39. The method as claimed in claim 26, wherein:

the second fill substance is used in a 9:1 ratio, or more, with respect to the first fill substance.

40. The method as claimed in claim 26, wherein:

the first fill substance is a liquid that solidifies at a temperature less than 100° C., especially at a temperature around 0° C.

41. The method as claimed in claim 26, wherein:

the first fill substance is at least partially water.

42. The method as claimed in claim 26, wherein:

the first fill substance is at least partially wax, oil or fat.

43. The method as claimed in claim 26, wherein:

the second fill substance is at least partially a grainy material, especially one having spherical particles.

44. The method as claimed in claim 26, wherein:

the second fill substance is at least partially a powder.

45. The method as claimed in claim 26, wherein:

the second fill substance is at least partially mineral.

46. The method as claimed in claim 26, wherein:

the second fill substance is at least partially organic.

47. The method as claimed in claim 26, wherein:

the second fill substance is at least partially metallic.

48. The method as claimed in claim 26, implemented using a press mold that is matched to the desired form of the measuring tube to be manufactured and that has a punch and a cavity, wherein the step of bending the tube section through introduction of a bending force that acts at least sectionally externally on the tube section includes the following steps: inserting the tube section, equipped with the forming core, into the opened press mold and positioning it between punch and cavity; and closing the press mold and bending the tube section by means of a relative motion of punch and cavity towards one another.

49. The method as claimed in claim 48, further comprising the steps of:

opening the press mold after the bending of the tube section; and

removing the bent tube section from the opened press mold.

50. Use of a bent tube section produced by means of the method of claim 26 as a measuring tube of a vibration-type measurement pickup, especially a Coriolis mass flow measurement pickup.