DE102007005670A1 - Magnetically inductive flow measuring device, has temperature sensor to measure temperature of medium, and embedded in material of measuring tube and arranged spatially to flow channel through which medium flows - Google Patents

Abstract

The device (1) has a measuring tube (2) including a flow channel (3) through which a medium flows. A temperature sensor (4) measures the temperature of the medium, and is embedded in a material of the tube and arranged spatially to the channel. The tube has a recess in which the sensor is arranged by a transition fit or an interference fit. The sensor is glued in the recess. The sensor is arranged in the tube in such a manner that a minimum residue wall (12) is provided between the sensor and the channel. An independent claim is also included for a method for manufacturing a magnetically inductive flow measuring device.

Description

The The invention relates to a magneto-inductive flowmeter with a Temperature sensor and a method for producing such Flowmeter.

The Invention is in the field of metrology for pipelines. Such pipelines are especially used to liquid or gaseous media to transport. When transporting them, there is often a need to to determine the exact flow rate of the medium. This is under Using a flowmeter possible, which is the principle uses the magnetic induction. In such flow meter, the also referred to as MIDs for short, the flow rate of the Medium through a measuring tube with the aid of a magnetic field and two measuring electrodes. The magnetic field penetrates when measuring the electrically non-conductive measuring tube and simultaneously the flowing through the measuring tube Medium. Becomes a charge carrier containing medium from a magnetic field perpendicular to its flow direction penetrated, the charge carriers from the magnetic field become transverse deflected to the flow direction and transverse to the magnetic field. Are located on the pipe walls two measuring electrodes, so falls between these an induced voltage. This induced voltage can over the Measuring electrodes are tapped and is a measure of the flow rate.

In addition to Measuring the flow often requires the temperature of the flowing through Medium to capture. This information can be used, for example be to correction factors for to determine the flow measurement. The determination of such correction factors makes sense, since the density of the medium changes depending on the temperature and this can have an influence on the flow measurement. Furthermore The temperature of the medium can also be used as an independent measure for checking the Condition of the medium can be used. This can be z. B. at temperature critical Be relevant to media or processes. Furthermore, the provision of Temperature of the medium also makes sense to damage the flowmeter by an overheating to avoid.

Around determine the temperature of flowing through a flow meter medium are Applicant Flowmeters known, which means for detecting the temperature of Include media. The Applicant is two different variants known by means for detecting the temperature of the medium.

According to one Variant is a temperature sensor in the measuring tube of the flowmeter so arranged that the temperature sensor with the through the measuring tube flowing Medium is in direct contact. The temperature sensor breaks through the wall of the flow channel and projects into the same for a contact formation with the flow medium into it. However, this approach has changed the fact proved by the fact that by the intrusion of the temperature sensor in the flow channel the flow characteristics of the flowing through Medium changed becomes. In certain circumstances is a turbulent flow the consequence, which the flow measurement result as well as the reliability of the measuring structure deteriorates.

Further the applicant is another variant for temperature detection known. Accordingly, there is a temperature sensor on the outside attached to the measuring tube, in particular temperature sensors be placed in the form of a cuff around the measuring tube. At this Approach, however, the fact has proved to be disadvantageous that such, not directly in contact with the flow medium in contact Temperature sensors of a time delay in the measurement of Actual temperature of the flow medium subject. This in particular represents with rapidly changing temperatures of the flowing through Medium opposite the above explained, first variant is a disadvantage. A reliable temperature detection of flowing through Medium is only for media with approximately constant temperature and only with a time delay guaranteed according to which the temperature gradient between the temperature of the Flow medium and the temperature of the temperature sensor receiving Measuring tube section goes to zero.

In front In this background, the present invention has the object to provide a magnetic inductive flowmeter, which is a reliable temperature measurement of the flowing through Medium guaranteed without the flow characteristics to influence it.

These The object is achieved by a Flowmeter with the features of claim 1 and the features of Claim 9 and by a method with the features of Claim 35 or the features of claim 37 solved.

Accordingly, a flow meter is provided with a measuring tube having a flow passage through which a medium to be measured flows and with at least one temperature sensor for measuring the temperature of the flow medium, wherein the temperature sensor embedded in the material of the measuring tube and spaced from the flow channel and thus apart is arranged to the medium flowing in the flow channel.

The inventive method for producing such a magnetic inductive flowmeter has the process steps that provided an injection mold with a cavity is formed, which as a negative to a measuring tube of a flowmeter is, and that a temperature sensor is inserted into the injection mold and further injecting a plastic melt into the cavity, wherein the plastic melt completely flows around the temperature sensor.

Of the Invention is based on the idea, the temperature sensor as possible close to the flowing through Medium to place, but an influence of the through the measuring tube flowing Medium to avoid. To accomplish this, is the temperature sensor not in direct contact with the medium. Correspondingly, too no irregularities caused by the temperature sensor the flow the flow medium are caused disadvantageously. According to the invention is a Temperature measurement even at fast changing temperatures of the Medium possible, because only a slight residual wall thickness remains between the temperature sensor and the flow channel and a rapid temperature balance between the temperature of the Flow medium and the temperature measuring point guaranteed becomes. Furthermore, it is advantageous in the present invention to look at that damage of the temperature sensor, for example by aggressive media, not can occur. Also can no deposits of the medium form on the temperature sensor. A time-dependent change the temperature measurement results is thereby advantageously avoided. Since the temperature sensor is further embedded in the material of the measuring tube is arranged, this is in a precisely defined Position. Moving the temperature sensor and resulting irregularities the temperature measurement result, are thus largely prevented.

at the method according to the invention for producing the flowmeter described above particularly advantageous to consider that the production of the measuring tube and additionally the connection of the measuring tube with the temperature sensor in one common step takes place. An additional manufacturing step deleted Consequently. It is also possible To produce the necessary injection mold very precisely and thus ensuring that the temperature sensor is spaced apart the flow channel and a medium flowing in the flow channel is arranged.

Of Another is a second inventive magnetic inductive flowmeter, with a Provided measuring tube, which has a flow channel through the medium to be measured flows through, and at least two measuring electrodes, which are arranged embedded in the material of the measuring tube, and with at least one temperature sensor for measuring the temperature of the flow channel flowing Medium, wherein the temperature sensor in or on the measuring electrode is arranged.

Further a method for producing such a flow meter is provided, wherein Initially, an injection mold having a cavity, which as a Negative to a measuring tube of a flowmeter formed is provided. Subsequently, at least one measuring electrode inserted in the injection mold. Thereafter, a plastic melt into the cavity injected, with the measuring electrodes of the plastic melt to be flown around. Furthermore, a temperature sensor on the Measuring electrode attached.

Especially is advantageous to look at this variant of the flowmeter according to the invention, that recording the temperature directly in the area of the measuring tube takes place, in which the flow rate is recorded. This is particularly useful to reliable correction factors for flow measurement to determine. In addition, since the measuring electrodes are generally made of metals, which is known to have a high thermal conductivity , the temperature sensor detects the temperature very quickly of the medium. This makes it possible, very much to detect fast and dynamic temperature changes of the medium and to respond to them.

advantageous Embodiments, developments and improvements of the invention are the dependent claims and the description in conjunction with the figures of the drawing refer to.

The Measuring tube has according to a preferred embodiment, a recess in which the temperature sensor is arranged. Such a recess can easily be made in such a way that the temperature sensor is at a defined distance from the Flow channel is located. With regard to the shape of this recess this can be adapted to the shape of the selected temperature sensor become. So can These temperature sensors can be round or square or have any other shape.

In a further preferred embodiment, the temperature sensor is arranged in the form of a transition or a press fit in the recess of the measuring tube. This is about a defined dimensional ratio of the recess of the measuring tube possible with respect to the temperature sensor. Since the temperature sensors are usually predetermined dimensions having purchased parts, it makes sense to adjust the dimensions of the recess of the measuring tube accordingly. If a press fit is to be achieved, the dimensions of the recess of the measuring tube are to be selected to be slightly smaller than the dimensions of the temperature sensor. In the case of a transitional fit, the dimensions correspond approximately to the dimensions of the temperature sensor. By selecting an appropriate fit, it is possible to position the temperature sensor in a precisely defined position on the measuring tube. If, moreover, this interference fit system is designed as a press fit, it is possible to attach the temperature sensor to the measuring tube without additional connection techniques or connecting means.

In In another embodiment, the temperature sensor is in the recess glued to the measuring tube. This can be particularly useful if the measuring tube is made of a very hard material and thus a press fit between the temperature sensor and the recess of the measuring tube not possible is because damage to the Temperature sensor is to be feared during pressing. A fixation The temperature sensor can in this case by an adhesive respectively. About that In addition, it can also be useful when using a press fit be to stick the temperature sensor in the recess of the measuring tube, to exclude a shift of the same.

In Another preferred embodiment is the temperature sensor arranged in the measuring tube, that between this and the flow channel a minimal residual wall remains. Particularly preferred a thickness of the residual wall in a range of 0.1 to 0.5 mm and most preferably 0.2 mm. Such a residual wall ensures that the temperature sensor is not directly in contact with the medium stands, but still the already explained heat conduction not or only slightly that Affect the measurement result, as this residual wall as possible is made thin.

Further Preferably, the temperature sensor protrudes into the flow channel and is provided with a coating that the temperature sensor separates from flowing in the flow channel medium. A such coating protects on the one hand the temperature sensor against the influence of aggressive media and so can to the other be thin, that heat conduction effects negligible become low. Thus, extremely accurate temperature readings can be obtained determine. Further, the coating may have a rounded shape such have that flow characteristic the flow medium is not or only insignificantly influenced becomes. According to one Another preferred embodiment, the measuring tube longitudinal and / or transverse ribs and the temperature sensor is disposed within one of these ribs. Since the measuring tube has the most material in the area of the ribs, can at this point by a correspondingly executed recess a good leadership of the Temperature sensor can be achieved. The probability that the temperature sensor in operation of the flowmeter, z. B. shifts due to possible vibrations, this is only very low. The temperature sensor can of course also between two ribs be arranged when no shifts of the temperature sensor to fear are.

Further Preferably, the measuring electrodes are designed in two parts. By this bipartite makes it possible for the one part of the measuring electrode is a first material and the second one Measuring electrode part, which is connected to the first part, a second material to use, wherein the material flow channel side a good Contacting with the medium guaranteed and is also corrosion resistant, and being the outside Measuring electrode part another property, such. B. a good one solderability, having. Is the second measuring electrode part good solderable, so can be a soldering the measuring electrode already be carried out at a low temperature and the measuring tube is soldered not overheated or even damaged.

Further Preferably, the temperature sensor is soldered to the second part and / or taped. This makes it easy to integrate the temperature sensor into the flowmeter. By a good solderability the second measuring electrode part is a reliable solder joint of the temperature sensor the measuring electrode possible.

According to one another preferred embodiment, the measuring electrode has a recess, within which the Temperature sensor is arranged. This recess is in terms of their shape and dimensions also adapted to the temperature sensor. By such a recess is an exact positioning of the Temperature sensor possible.

In a further preferred embodiment is the recess of the measuring electrode as a bore in the longitudinal direction the measuring electrode formed. This is particularly advantageous because a hole is easy to make and temperature sensors mostly have a round cross-section. An integration of a Temperature sensor in the measuring electrode is characterized by this type of execution of Recess of the measuring electrode in a simple manner possible.

Preferably is between the temperature sensor and the recess of the measuring electrode a thermally insulating and / or a thermal expansion arranged compensating material. The use of such As an intermediate layer material is advantageous because due the expected different thermal expansions of the temperature sensor and the measuring electrode during operation of the flowmeter thermal stresses could be induced through the damage the temperature sensor and / or measuring electrode would be possible. Such an intermediate layer is advantageous in the position to compensate for different thermal expansions.

According to one Another preferred embodiment is in the recess of the Measuring electrode arranged temperature sensor directly with a flow channel flowing Medium in contact. By this type of arrangement of the temperature sensor is guaranteed that the temperature sensor directly absorbs the temperature of the medium. Consequently can, even if the temperature of the medium changes very dynamically, this temperature change be recorded promptly.

Further Preferably, the measuring electrodes protrude in the region of the measuring cross section into the flow channel and communicate with a medium flowing in the flow channel in contact. This type of arrangement of the measuring electrodes is a cleaning of the same through the medium flowing through the measuring channel possible.

Of Further preferably, the measuring electrodes are galvanic from one flowing in the flow channel Medium separated. This will prevent the measuring electrodes be attacked by the medium and / or corrode. Furthermore, will avoided that the medium from the measuring electrode material soiled becomes.

In In another preferred embodiment, the measuring tube is made Plastic, glass and / or ceramic or is inside with at least one of these materials lined. Because the magnetic field in the flow measurement the pipe wall of the measuring tube must penetrate, the measuring tube may not be ferromagnetic. This applies to the above materials. Would be the measuring tube ferromagnetic, so would the measuring tube deflect the magnetic field. In particular, it is advantageous it to use a plastic material. Complicated geometries can relatively easy in a plastic injection molding process getting produced.

Preferably has the measuring tube PEEK (PEEK = polyetheretherketone) on or is made of PEEK. PEEK is a high temperature resistant thermoplastic Plastic, which has its melting temperature at about 335 ° C. Instead of the use of PEEK Other ketones, such as. PEK, PEEEK, PEEK EK or PEEKK. Such polyetheretherketone materials are resistant to almost all organic and inorganic media resistant. Furthermore, these materials are also advantageous because they are up to a temperature of about 280 ° C resistant against hydrolysis. In summary, it can be stated that PEEK opposite other plastics a very good chemical and thermal resistance having. This is an employment of one with such a material equipped measuring tube even with aggressive flow media possible with a high temperature. Further preferred is PEEK due to its high strength and Stiffness preferably used. Other preferred materials for the manufacture of the measuring tube are PPS (= polypheylene sulfide) and IXEF (= polyarylamide). Both materials have a high resistance to chemicals, temperature resistance and strength on.

Of Further preferably, the temperature sensor is an NTC or a PTC and in particular a PT100 or PT1000 temperature sensor. Under a NTC temperature sensor does one understand a thermistor, which has a negative temperature coefficient, d. h. that whose resistance decreases with increasing temperature. Corresponding conversely, a PTC temperature sensor is understood to mean a PTC thermistor has a positive temperature coefficient. In particular, be for one reliable Temperature measurement PT100 and PT1000 temperature sensors used. These sensors are based on a platinum alloy. The name 100 or 1000 denotes the reference resistance of 100 or 1000, respectively Ohm at a temperature of 0 ° C. The resistance of these sensors increases with increasing temperature approximately linear. Accordingly, very easily and reliably via a resistance change of the sensor, the z. B. over a Current or voltage change is determined, closed to the temperature of the temperature sensor become. Can be used such temperature sensors in a range of -200 ° C to 850 ° C.

Advantageously, the temperature sensor is completely encased in glass. Since such temperature sensors are highly sensitive components, mechanical influences should be prevented since they could falsify the measurement result or even damage the sensor. By wrapping with a glass material and / or a ceramic mass is thus prevented that mechanical stresses are introduced into the sensor. Furthermore, by such a sheath, the chemical resistance of the sensor can be increased. In addition, it is of course possible, the sensor only partially, for example the flow channel facing side, to coat.

In In another preferred embodiment, the flowmeter has an evaluation device on. Since the evaluation device is thus part of the flowmeter, are the voltages measured at the measuring electrodes as well as Furthermore, the temperature values of the temperature sensor in the immediate Close to the measuring point evaluated. An additional external device to evaluate these measured values is no longer necessary here. Thereby Is it possible, to achieve a very compact construction of the flowmeter. A falsification of the measured values due to a connection between the Temperature sensor and / or the measuring electrodes and the separated external evaluation could occur, is thus advantageous bypassed.

The Evaluation of the evaluation is according to a preferred embodiment, at least partially on a circuit board arranged. Such a circuit board is often used to different electronic components and their connecting lines with each other to link, so that they are mounted together in a housing of an electronic device can be. Through the electronic components, electrical and electronic Functions, which for the operation of the flowmeter are required to be performed. Such functions relate to the measurement and evaluation of the measurement results and a possibly derived control. These electronic components are typically arranged on a single compact board and can so in one piece in the case of the flowmeter be mounted.

Further it is preferred that the printed circuit board is partially or completely flexible is trained. A partially flexible circuit board is often called Semiflex or rigid flex PCB designated. A complete flexibility can z. B. can be achieved when the entire transmitter the evaluation device is located on a conductor film. At a partial foldability of execution the circuit board is the evaluation only in some areas foldable. This foldability can be harnessed to the transmitter to be arranged in a limited space within the housing. As for the transmitter Thus, only a small footprint is needed, the flowmeter can be very compact accomplished be. In a preferred embodiment, the circuit board at least one and at least two inflexible printed circuit board segments which are interconnected by a flexible conductor film section are. This structure of the circuit board can electronic components arranged on several rigid, inflexible circuit boards and segments be, wherein the circuit board by means of the flexible conductor film sections is foldable. This Faltbarkeit is used to the evaluation to be arranged on the measuring tube of the flowmeter in such a way that the circuit board in the radial direction of the measuring tube at least partially encloses. This type of arrangement is a very compact overall structure of the flowmeter possible.

Additionally preferred is that the flow meter a further temperature sensor which is locally separated from the measuring tube is arranged. This makes it possible that the temperature of the medium flowing through the pipe system also at a local can be recorded by the measuring tube separate location. is the temperature sensor of the flowmeter and / or the further temperature sensor and / or the measuring electrodes with the evaluation device electrically connected, so can the measured values determined by these elements are evaluated directly in the evaluation device become. That's the way it is the temperature sensor within the measuring tube and also above the from this local separate temperature sensor possible, a possibly occurring temperature difference between them determine. The determined temperatures of both sensors can be used for more Evaluation purposes are used. Of course, the temperature sensors must and / or the measuring electrodes are not necessarily electrically connected to the evaluation device be, but connect over Radio and / or an optical, inductive and / or capacitive connection is also possible.

According to one Another preferred embodiment has at least one of the printed circuit board segments one of the evaluation electrically contacted hole on, to which the measuring electrode is soldered. This will be advantageous avoided that between the evaluation and the measuring electrode an additional Connecting line is necessary. Possible errors due to the use of such a connecting line are consequently avoided.

Moreover, it is preferred that the temperature sensor is soldered to the solder joint between the measuring electrode and the bore of the evaluation device. This type of arrangement of the temperature sensor, this can also be integrated later in a flow meter. Furthermore, no special recesses, characteristics or the like for receiving the temperature sensor are necessary at the measuring electrode. Since the measuring electrodes are also made of metallic materials, which usually have a high thermal conductivity, the in the medium prevailing temperature with only a small temporal offset passed to the temperature sensor.

According to one Another preferred embodiment evaluates the evaluation an information about the flow rate, the flow rate of the medium, the duration of the flow, the temperature of the medium in the range the flow measuring point, the geometry of the flow channel and / or the temperature of the medium outside the flowmeter off. Through this information, the Flowmeter also used as a heat meter become. So the flow meter is the cross section of the flow channel known in the area of the measuring point and with this information, the Density of the medium and the flow rate of the medium the flow rate can be calculated. With the help of Temperature of the medium in the area of the flow measuring point and the Temperature of the medium outside the flow measuring point, which by the other temperature sensor it is about it out possible, the total amount of heat flow over one determine a certain period of time. If the flow meter z. B. is used in a heating system, it is possible over this Heat flow, the energy consumed within a defined period of time determine. This energy consumption can z. B. from an energy-supplying Companies are used for billing purposes.

Further preferred is a method for producing a magneto-inductive Flowmeter proposed. In this case, an injection mold is provided, the a cavity which forms as a negative to a measuring tube of a flow meter is. Subsequently a temperature sensor is inserted into the injection mold and the Plastic melt in the cavity injected, wherein the temperature sensor of the plastic melt Completely is flown around.

According to one second preferred method for manufacturing a magnetic inductive flowmeter is provided in an initial step also an injection mold, the one cavity which is formed as a negative to the measuring tube of the flowmeter. Subsequently the at least one measuring electrode is inserted into the injection mold and the molten plastic injected into the cavity, the measuring electrode is surrounded by the plastic melt. Subsequently, will the temperature sensor attached to the measuring electrode.

According to one preferred embodiment, the measuring electrode has a recess on, in which introduced an at least partially flexible lining becomes. Subsequently the temperature sensor is preferably pressed into this lining. By This lining will prevent the temperature sensor from entering whose mounting is damaged. Such an at least partially flexible lining is also capable of any differing thermal expansions of the temperature sensor and the measuring electrode during operation of the flowmeter compensate.

Furthermore Preferably, the temperature sensor is bonded to the measuring electrode. This will prevent the temperature sensor from opening during the Operation of the flowmeter shifts.

at In both methods, the temperature sensor is particularly preferred electrically connected to the evaluation device and in particular soldered to this. Furthermore, the temperature sensor is preferably at the same solder joint as the measuring electrode soldered to the evaluation.

The Invention will be described below with reference to exemplary embodiments with reference explained in more detail on the accompanying figures of the drawing.

From show the figures:

1 a flow meter according to a first preferred embodiment of the present invention;

2a - 2d Various variants of the arrangement of the temperature sensor according to the first preferred embodiment 1 ;

3 a flow meter according to the invention according to a second preferred embodiment of the present invention;

4a . 4b for example, a measuring tube and the evaluation device;

5a - 5e Various variants of the arrangement of the temperature sensor according to the second preferred embodiment of 3 ;

6 the inventive method for producing the flowmeter according to the first preferred embodiment of the 1 and 2a - 2d ; and

7 the inventive method for producing the flowmeter according to the invention according to the second preferred embodiment of the 3 and 5a - 5e ,

In the figures of the drawing, the same reference numerals designate the same or functionally identical elements and components, as far as nothing Ge the same is given.

1 illustrates a schematic cross section of a first, very general embodiment of the flowmeter according to the invention. Essential components of the flowmeter according to the invention according to this embodiment are the measuring tube 2 as well as the temperature sensor 4 , The measuring tube 2 has an internal flow channel 3 through which the medium to be measured flows. To make this flow possible, the measuring tube points 2 Further, an inlet opening 6a and an outlet opening 6b on. Inside the wall of the measuring tube 2 is a temperature sensor 4 arranged. This temperature sensor 4 is so in the wall of the measuring tube 2 integrated, that this only by a minimal remainder wall 12 with the smallest possible wall thickness of one in the flow channel 3 flowing medium is separated. It is possible to connect the temperature sensor 4 over a connecting line 5 z. B. with a device, not shown, for evaluating the sensor signals. The structure described above is in a housing 7 arranged. This case 7 protects the test setup from damage due to environmental influences. In the illustrated embodiment are the longitudinal axes of the measuring tube 2 and the housing 7 on a common longitudinal axis 8th , However, this is not a limiting feature of the invention, but these axes may well have a certain offset.

The 2a - 2d show the flowmeter according to the invention according to the first preferred embodiment 1 in detailed illustrations with different configurations. In 2a a side view of the measuring tube is shown. This measuring tube 2 is cut in the section plane AA. This cut is in 2 B shown and in this section is the temperature sensor 4 clearly visible. 2c shows the arrangement of the temperature sensor 4 inside the measuring tube 2 according to a first variant in a detailed view X1. 2d shows an enlarged section X2 with the arrangement of the temperature sensor 4 in the measuring tube 2 according to a second variant.

How out 2a can be seen, the measuring tube 2 an inlet opening 6a and an outlet opening 6b on, through which the medium enters the measuring tube 2 entry or exit. The sectional plane AA, in which also the temperature sensor 4 is located, has a distance x to the center of the measuring tube 2 , It is obvious that this distance x is variable and not, as indicated in the illustrated embodiment, relatively far from the center of the measuring tube 2 must be located away. So it can be quite useful, the cutting plane AA and thus also the temperature sensor 4 align relatively close to the center of the measuring tube, since at this point the flow measurement of a through the flow channel 3 of the measuring tube 2 flowing medium takes place. This type of arrangement ensures the determination of reliable correction factors for the flow measurement.

2 B shows the cross section along the cross-sectional plane AA. It is evident from this view that on the outer shell of the measuring tube 2 ribs 16 are located.

The use of ribs is particularly useful when the measuring tube 2 made by injection molding of a plastic. Material accumulation and the resulting casting defects of the material incidence is avoided and still high strength and rigidity of the measuring tube 2 achieved advantageous. Inside the measuring tube 2 there is a flow channel 3 through which the medium to be measured flows. In the wall of the measuring tube 2 is a temperature sensor 4 arranged. A detailed section X of the area in which the temperature sensor 4 in the wall of the measuring tube 2 can be arranged, the 2c and 2d be removed.

2c shows the arrangement of a temperature sensor 4 in a measuring tube 2 according to a first variant. The wall of the measuring tube 2 indicates the inclusion of the temperature sensor 4 a recess 10 on. This recess 10 of the measuring tube 2 is designed such that at its flow-channel-side bottom a residual wall 12 remains, which the recess 10 from the flow channel 3 separates. This residual wall 12 has a residual wall thickness h, which is preferably in the range of 0.1 to 0.5 mm and preferably 0.2 mm. In the illustrated variant, the recess 10 of the measuring tube 2 in the area of a rib 16 arranged. By this type of execution, a good guidance of the temperature sensor 4 reached. This recess 10 of the measuring tube 2 but not necessarily in the area of a rib 16 but can also be at another point of the measuring tube 2 , for example between the ribs.

The 2d illustrates another preferred arrangement variant of the temperature sensor 4 in the wall of the measuring tube 2 , The measuring tube also has a recess 10 for receiving the temperature sensor 4 on. In contrast to the already described recess of the measuring tube 2 However, in the first variant this is not separated in this embodiment of a residual wall of the flow channel. The temperature sensor 4 protrudes into the flow channel 3 into it. Nevertheless, the temperature sensor is 4 not directly with one through the flow channel 3 flowing medium in contact, but is with a coating 14 provided the tem perature sensor 4 separates from the medium. The coating becomes advantageous 14 , as in 2d is schematically illustrated rounded in such a way that the flow characteristics of the flowing medium is not or only insignificantly influenced. In particular, if the flow channel 3 An aggressive medium flows through such a coating 14 a protection of the temperature sensor 4 possible. This coating preferably has 14 a high chemical resistance and also has a good thermal conductivity. As a result, the temperature of the medium is quickly forwarded to the temperature sensor and the temperature can be recorded despite the separation of temperature sensor and medium with a high temporal resolution.

3 shows a schematic cross section of a second, very general embodiment of a flow meter according to the invention. The flow meter is denoted by the reference numeral 1 Mistake. Essential components of this flowmeter are the measuring tube 2 and also the measuring electrodes 20 and at least one temperature sensor 4 , The measuring tube 2 has a flow channel 3 for a flow of a medium to be measured. In order to allow an inlet and an outlet of the medium, there is an inlet opening 6a and an outlet opening 6b intended. Within the wall of the measuring tube are two measuring electrodes 20 arranged. If a medium now flows through the flow channel, a voltage signal proportional to the flow rate can be tapped off at these two measuring electrodes. In addition, inside the measuring electrode 20 a temperature sensor 4 arranged. Advantageously located in the present second embodiment, the temperature sensor 4 directly in the area of the measuring point in the flow channel 3 in which the voltage value dependent on the flow rate is also tapped. As a result, any correction factors for the flow measurement, depending on the temperature of the medium, can be reliably determined.

The 4a and 4b show the measuring tube 2 as well as the evaluation device 28 in a disassembled and assembled state, this type of execution of the measuring tube 2 and the transmitter 28 both for the first embodiment of the 1 and 2 and the second embodiment of the 3 Has validity. The evaluation device 28 is arranged on a circuit board, which both rigid circuit board segments 30 as well as flexible sections 34 having. For the sake of clarity, the individual electronic elements are on the rigid printed circuit board segments 30 as well as the flexible sections 34 are arranged, not shown. At the flexible sections 34 that z. B. may be formed as a conductor film, the rigid circuit board segments 30 at least partially foldable to each other. This allows the rigid circuit board segments 30 and the flexible sections 34 and thus the evaluation device 28 in this way around the measuring tube 2 to fold that this is the measuring tube 2 at least partially enclose. That of the evaluation device 28 enclosed measuring tube 2 is in 5b shown. Such an arrangement is considered to be extremely compact and space-saving. A particular advantage is also that it is possible by such a fold, between the measuring electrodes 20 of the measuring tube 2 and the evaluation device 28 to make an electrical contact. These are the measuring electrodes 20 during assembly of the evaluation device 28 into the hole 32 in the rigid circuit board segments 30 introduced, the z. B. have an electrically conductive surface and which are further electrically connected to the evaluation device. An electrical contact through an additional connection line is therefore not necessary.

5a - 5e illustrate the flowmeter according to the invention 1 according to the second preferred embodiment 3 , In the 5c . 5d and 5e are different variants of the arrangement of the temperature sensor 4 shown in a detailed view.

5a shows the measuring tube 2 and the evaluation device attached thereto 28 in the assembled state in a side view. This arrangement has the respect to the 4b explained structure. Centered through the flowmeter 1 is a sectional plane BB laid. This cut is in the 5b shown. It is evident from this view in addition to the measuring tube 2 the location of the measuring electrodes 20 in which at least one temperature sensor 4 is arranged. To better clarify the possible arrangement types of the temperature sensor 4 within or at the measuring electrodes 20 the relevant area in the detail view Y is shown enlarged.

The 5c - 5e illustrate this detail view Y with the different possibilities of the arrangement of the temperature sensor 4 inside or at the measuring electrode 20 , The measuring electrode 20 consists of a first measuring electrode part 24 in the area of the flow channel 3 is arranged, and further from a second measuring electrode part 22 connected to the first measuring electrode part 24 connected, but on the flow channel 3 opposite side of the measuring electrode is arranged. Due to this bipartite, it is possible to use the measuring electrode 20 to equip with features that are a one-piece measuring electrode 20 could not own. So z. B. flow channel side, the first measuring electrode part 24 made of a corrosion-resistant stainless steel whereas the second measuring electrode part 22 has a good solderable material and thus easy contact with the evaluation 28 allows. In the illustrated measuring electrodes 20 is the second measuring electrode part 22 on the first measuring electrode part 24 screwed. However, this is just one possible type of connection. Alternatively, the second measuring electrode part could 22 also in the first measuring electrode part 24 be pressed or pressed on this. However, it is apparent that this bipartite is not absolutely necessary, but that the measuring electrode can also be made in one piece or in several parts.

In the in the 5c illustrated variant of the arrangement of the temperature sensor 4 this is at the second measuring electrode part 22 over the solder joint 26 soldered. Appropriately, via the solder joint 26 also in the same step the second measuring electrode part 22 with the evaluation device 28 soldered. The second measuring electrode part 22 is in a hole 32 in the rigid circuit board segment 30 the evaluation device 28 introduced. However, it can be seen that the temperature sensor 4 not simultaneously with the first measuring electrode part 22 on the rigid circuit board segment 28 must be soldered, but that this can also be subsequently soldered.

In 5d is a second variant of the arrangement of the temperature sensor 4 shown in which the temperature sensor within the measuring electrode 20 is arranged. The measuring electrode is inside the material of the measuring tube 2 arranged. In addition, the measuring electrode is directly connected to the flow channel 3 in contact. For receiving the temperature sensor 4 has the first measuring electrode part 24 a recess 36 the measuring electrode 20 on, which is carried out continuously. Thus, the inside of the recess 36 the measuring electrode 20 arranged temperature sensor 4 , directly with one in the flow channel 3 flowing medium in contact. This is particularly advantageous since a direct recording of the temperature of the medium by the temperature sensor 4 is possible. Dynamic changes in the temperature of the medium can thus be recorded with a high temporal resolution. The second measuring electrode part is contacted 22 the measuring electrode 20 with the evaluation device 28 over a hole 32 in the rigid circuit board segment 30 , This contact can z. B. via a solder joint.

In 5e is another way of arranging the temperature sensor 4 shown in the measuring electrode. In this variant, the first measuring electrode part 24 also a recess 36 the measuring electrode 20 on. However, this is not continuous, but it remains a bridge 23 , the recess 36 the measuring electrode 20 from the flow channel 3 separates. In this recess 36 the measuring electrode 20 is the temperature sensor 4 arranged. Through the jetty 23 is the temperature sensor 4 from one in the flow channel 3 isolated medium. Such an arrangement is particularly useful when it is feared that the temperature sensor 4 due to an aggressive medium could be damaged. The measuring electrode can be contacted 20 with the evaluation device 28 also via a hole 32 in the evaluation device 28 ,

6 shows a method for producing a magnetic inductive flowmeter, said manufacturing method for in the 1 and 2 illustrated embodiment can be applied. In a first step S1, an injection mold is provided, which has a cavity, which is formed as a negative to the measuring tube of the flowmeter. In the second step S2, the temperature sensor 4 inserted in the injection mold. Subsequently, in step S3, the measuring electrodes 20 inserted in the injection mold. Then, in step S4, the injection of the plastic melt, wherein in particular the temperature sensors and the measuring electrodes are completely enveloped by the plastic melt. In step S11, the temperature sensor and / or the measuring electrode is electrically connected to the evaluation device.

7 provides a method of making the flowmeter according to the second, in the 3 and 5 In a first method step S5, an injection mold is also provided, which has a cavity which is formed as a negative to the measuring tube of the flowmeter. Subsequently, in the step S6, the measuring electrodes 20 inserted in the injection mold. In step S7, the plastic melt 40 injected into the cavity, with the measuring electrodes 20 from the plastic melt 40 to be flown around. Subsequently, in step S8, at least one temperature sensor 4 at the measuring electrode 20 appropriate. In addition, in step S9, the temperature sensor 4 soldered to the measuring electrode and / or glued. In the concluding step S10, the temperature sensor and / or the measuring electrode is connected to the evaluation device. This is the preferred procedure, but it is also possible to interchange the method steps S8 and S6, ie the temperature sensor is first attached to the measuring electrode before the measuring electrode is inserted into the injection mold.

The The present invention has been described above with reference to exemplary embodiments It is not limited to this, but in many ways and modifiable.

1

Flowmeter

2

measuring tube

3

Flow channel

4

temperature sensor

5

connecting line temperature sensor

6

opening

6a

inlet port

6b

outlet

7

casing

8th

longitudinal axis of the flowmeter

10

recess of the measuring tube

12

residual wall

14

coating on the measuring electrode

16

rib

20

measuring electrode

22

second Measuring electrode member

23

web

24

first Measuring electrode member

26

soldered point

28

evaluation

30

rigid PCB segment

32

drilling

34

flexible sections

36

recess the measuring electrode

40

Plastic melt

H

Remaining wall thickness

S1

Provide an injection mold (method 1)

S2

insert of the temperature sensor

S3

insert the measuring electrodes

S4

inject the plastic melt

S5

Provide an injection mold (method 2)

S6

insert the measuring electrode

S7

inject the plastic melt

S8

install the measuring electrode

S9

stick and / or soldering of the temperature sensor at the measuring electrode

S10

Connect the measuring electrode and / or the temperature sensor with the evaluation device (in one or two steps)

S11

Connect the measuring electrode and / or the temperature sensor with the evaluation device (in one or two steps)

Claims (42)

Magnetic inductive flowmeter with: - a measuring tube ( 2 ), which has a flow channel ( 3 ) through which a medium to be measured flows; and - with at least one temperature sensor ( 4 ) for measuring the temperature of the flow channel ( 3 ) flowing medium, wherein the temperature sensor ( 4 ) in the material of the measuring tube ( 2 ) and spaced from the flow channel ( 3 ) is arranged. Flowmeter according to claim 1, characterized in that the measuring tube ( 2 ) a recess ( 10 ), in which the temperature sensor ( 4 ) is arranged. Flowmeter according to claim 2, characterized in that the temperature sensor ( 4 ) in the form of a transition or a press fit in the recess ( 10 ) of the measuring tube ( 2 ) is arranged. Flowmeter according to claim 1 and 2, characterized in that the temperature sensor ( 4 ) in the recess ( 10 ) of the measuring tube ( 2 ) is glued. Flowmeter according to at least one of the preceding claims, characterized in that the temperature sensor ( 4 ) in the measuring tube ( 2 ) is arranged that between the temperature sensor ( 4 ) and the flow channel ( 3 ) a minimal residual wall ( 12 ) remains. Flowmeter according to claim 5, characterized in that the residual wall ( 12 ) has a wall thickness in a range of 0.1 to 0.5 mm and in particular of 0.2 mm. Flowmeter according to at least one of the preceding claims, characterized in that the temperature sensor ( 4 ) into the flow channel ( 3 ) and with a coating ( 14 ), which is the temperature sensor ( 4 ) from one in the flow channel ( 3 ) separates flowing medium. Flowmeter according to at least one of the preceding claims, characterized in that the measuring tube ( 2 ) Longitudinal and / or transverse ribs ( 16 ) and the temperature sensor ( 4 ) within one of the ribs ( 16 ) is arranged. Magnetic inductive flowmeter with: - a measuring tube ( 2 ), which has a flow channel ( 3 ) through which a medium to be measured flows; At least two measuring electrodes ( 20 ), which in the material of the measuring tube ( 2 ) are arranged; and at least one temperature sensor ( 4 ) for measuring the temperature of the flow channel ( 3 ) flowing medium, wherein the temperature sensor ( 4 ) in or on the measuring electrode ( 20 ) is arranged. Flowmeter according to claim 9, characterized in that the measuring electrodes ( 20 ) are made in two parts. Flowmeter according to claim 10, since characterized in that a first part ( 24 ) of the measuring electrode ( 20 ) at the flow channel ( 3 ) and a second part ( 22 ) of the measuring electrode ( 20 ), with the first part ( 24 ), outside the measuring tube ( 2 ) is arranged. Flowmeter according to claim 11, characterized in that the first part ( 24 ) has a non-corrosive material and / or the second part ( 22 ) has a material which is good solderable. Flowmeter according to claim 11 and 12, characterized in that the temperature sensor ( 4 ) in the second part ( 22 ) is soldered and / or glued. Flowmeter according to at least one of claims 9 to 13, characterized in that the measuring electrode ( 20 ) a recess ( 36 ), within which the temperature sensor ( 4 ) is arranged. Flowmeter according to claim 14, characterized in that the recess ( 36 ) of the measuring electrode ( 20 ) as a bore in the longitudinal direction of the measuring electrode ( 20 ) is trained. Flowmeter according to claim 14 and 15, characterized in that between the temperature sensor ( 4 ) and the recess ( 36 ) of the measuring electrode ( 20 ) a heat-insulating and / or thermal expansion compensating material is arranged. Flowmeter according to at least one of claims 9 to 16, characterized in that the measuring electrodes ( 20 ) galvanically from one through the flow channel ( 3 ) flowing medium are separated. Flowmeter according to at least one of claims 14 to 17, characterized in that in the recess ( 36 ) of the measuring electrode ( 20 ) arranged temperature sensor ( 4 ) directly with a flow channel ( 3 ) flowing medium in contact. Flowmeter according to at least one of claims 14 to 17, characterized in that the measuring electrodes ( 20 ) into the flow channel ( 3 ) and with a flow channel ( 3 ) flowing medium in contact. Flowmeter according to at least one of the preceding claims, characterized in that the measuring tube ( 2 ) consists at least partially of plastic, glass and / or ceramic. Flowmeter according to at least one of the preceding claims, characterized in that the measuring tube ( 2 ) PEEK and in particular is made entirely of PEEK. Flowmeter according to at least one of the preceding claims, characterized in that the temperature sensor ( 4 ) is a PTC and in particular a Pt100 or a Pt1000 temperature sensor. Flowmeter according to at least one of the preceding claims, characterized in that the temperature sensor ( 4 ) is completely covered with glass. Flowmeter according to at least one of the preceding claims, characterized in that the flowmeter is an evaluation device ( 28 ) having. Flowmeter according to claim 24, characterized in that the evaluation device ( 28 ) has an evaluation, which is at least partially disposed on a circuit board. Flowmeter according to claim 25, characterized characterized in that the printed circuit board is partially flexible or completely flexible is trained. Flowmeter according to claim 26, characterized in that the printed circuit board at least one and in particular at least two inflexible printed circuit board segments ( 30 ) through a flexible conductor film section ( 34 ) are interconnected. Flowmeter according to claim 27, characterized in that the printed circuit board and / or the printed circuit board segments of the measuring tube ( 2 ) in the radial direction at least partially enclose. Flowmeter according to at least one of the preceding claims, characterized in that the flowmeter ( 1 ) has a further temperature sensor locally from the measuring tube ( 2 ) is arranged separately. Flowmeter according to claim 29, characterized in that the temperature sensor ( 4 ) of the flowmeter and / or the further temperature sensor and / or the measuring electrodes ( 20 ) with the evaluation device ( 28 ) are electrically connected. Flowmeter according to at least one of claims 24 to 30, characterized in that at least one of the printed circuit board segments ( 30 ) one of the evaluation device ( 28 ) electrically contacted bore ( 32 ), on which the measuring electrode ( 20 ) is soldered. Flowmeter according to at least one of claims 24 to 31, characterized in that the temperature sensor ( 4 ) at the soldering point ( 26 ) between the measuring electrode ( 20 ) and the bore ( 32 ) of the evaluation device ( 28 ) is soldered. Flowmeter according to at least one of claims 29 to 32, characterized in that the evaluation device ( 28 ) evaluates information about flow rate, flow rate, duration of flow, medium, medium temperature at the flowmeter location, flow channel geometry, and / or the temperature of the medium outside the flowmeter. Flowmeter according to claim 33, characterized in that the evaluation device ( 28 ) is designed as a heat meter. Method for producing a magnetic inductive flowmeter ( 1 ) according to any one of claims 1 to 8 and 20 to 34, comprising the steps of: - providing (S1) an injection mold having a cavity which acts as a negative to the measuring tube ( 2 ) of the flowmeter ( 1 ) is trained; Inserting (S2) the at least one temperature sensor ( 4 ) in the injection mold; and - injecting (S4) a plastic melt ( 40 ) into the cavity, the temperature sensor ( 4 ) is completely enveloped by the plastic melt. A method according to claim 35, characterized in that prior to injection of the plastic melt ( 40 ) additionally the measuring electrodes ( 20 ) are inserted into the injection mold. Method for producing a magnetic inductive flowmeter ( 1 ) according to any one of claims 9 to 34, comprising the steps of: - providing (S5) an injection mold having a cavity which acts as a negative to the measuring tube ( 2 ) of the flowmeter ( 1 ) is trained; - inserting (S6) the measuring electrodes ( 20 ) in the injection mold; Injecting (S7) a plastic melt ( 40 ) into the cavity, the measuring electrodes ( 20 ) from the plastic melt ( 40 ) are encircled; and - attaching (S8) the temperature sensor ( 4 ) on the measuring electrode ( 20 ). Method according to claim 37, characterized in that the measuring electrode ( 20 ) a recess ( 36 ), in which a flexible lining is introduced. A method according to claim 38, characterized in that the temperature sensor ( 4 ) is pressed into this lining. Method according to at least one of claims 36 to 39, characterized in that the temperature sensor ( 4 ) with the measuring electrode ( 20 ) is glued and / or soldered to this. Method according to at least one of claims 35 to 40, characterized in that the temperature sensor ( 4 ) and / or the measuring electrode ( 20 ) electrically with the evaluation device ( 28 ) is connected. Method according to at least one of claims 35 to 41, characterized in that the temperature sensor ( 4 ) at the same solder joint as the measuring electrode ( 20 ) at the evaluation device ( 28 ) is soldered.