DE102017116269A1 - Modular sensor arrangement - Google Patents

Abstract

The invention relates to a modular sensor arrangement, comprising:
- a fitting (1), the
a shaft (2) and
a conduit (3) arranged within the fitting (1) for guiding a flowable medium (4), the conduit (3) opening into the shaft (2) with an end portion (31) of the conduit (3), and
- a, in particular electrochemical, sensor (5) for determining and / or monitoring a process variable of the medium (4) which can be inserted into the shaft (2),
wherein the line (3) has an interchangeable nozzle (6) at its end section (31) which opens into the shaft (2), through which a medium (4) flowing in the line (3) flows against the sensor (5),
and wherein the flow is adjustable by means of the design and / or the orientation of the nozzle (6) in the end portion (31) in dependence on the medium (4) and / or of the sensor (5).

Description

The invention relates to a sensor arrangement, comprising: a valve having a shaft and a conduit disposed within the fitting for guiding a flowable medium, wherein the line opens into the shaft with an end portion of the conduit, and a, in particular electrochemical, sensor for determining and / or monitoring a process size of the medium that can be inserted into the shaft.

Electrochemical sensors are used in the laboratory and process measuring technology in many areas of chemistry, biochemistry, pharmacy, biotechnology, food technology, water management and environmental metrology for the analysis of measuring media, in particular of measuring liquids. By means of electrochemical measurement techniques, it is possible to record, for example, activities of chemical substances, for example ions, and thus correlated measured variables in liquids. The substance whose concentration or activity is to be measured is also called analyte. Electrochemical sensors may be, for example, potentiometric or amperometric sensors. Such electrochemical sensors are manufactured and distributed by the applicant in a variety of configurations.

A large number of the electrochemical sensors, for example amperometric disinfection sensors, have a membrane which is sensitive to the medium and establishes the sensory contact with the analyte which, for example, diffuses through the membrane. For the exact operation of such sensors is for example on the DE 10 2008 039 465 A1 directed. The diffusion through the membrane is dependent on the flow and therefore requires a defined minimum flow for the reliable determination of the correlated with the concentration of the analyte measurement.

Membrane covered sensors can be used in laboratory and process instrumentation in flow valves and operated by bypass. In this case, as a rule, a portion of a medium is automatically removed from a process, passed through a bypass comprising a flow-through fitting, analyzed in the flow-through fitting by means of a sensor, and then generally discarded.

The sensor is fixed in the fitting with a depth of insertion. The fixation of the sensor is ensured by a screw in the valve. For fixing and determining the depth of insertion of the sensors in the fittings they are provided with a solid collar or stop or a groove with a retaining ring and sealed by means of an O-ring. From the prior art, e.g. Sensors are known, which are designed with a solid collar, which is arranged on the shaft of the sensor and therefore only allows the realization of a predetermined insertion depth. In this case, a permanently installed nozzle is arranged at an end portion of an opening into the valve, the medium-carrying line, through which the medium flows to a nozzle facing the end face of the sensor, in particular the membrane.

The flow of the sensor through the medium, e.g. the achievement of a defined minimum flow is dependent in the prior art on the design of the sensor, such as a predetermined insertion depth, the application, as well as the predetermined configuration of the fixed nozzle. Depending on the design of the sensor, such as the type of membrane and the medium, therefore, a different flow of the sensor through the medium is needed. This has the disadvantage that the sensor is not in another fitting, e.g. can be installed by another manufacturer, since it is then not operated with an adapted to the sensor and / or the application flow. In the event of a change in the flow rate of the medium in the conduit, e.g. the flow of the sensor due to the application. Therefore, this situation can not be reacted flexibly.

The invention has for its object to provide a sensor assembly with a fitting, which is universally applicable.

• - eine Armatur, die
  • --einen Schacht und
  • --eine innerhalb der Armatur angeordnete Leitung zur Führung eines fließfähigen Mediums aufweist, wobei die Leitung mit einem Endabschnitt der Leitung in den Schacht mündet, und
• - einen, insbesondere elektrochemischen, Sensor zur Bestimmung und/oder Überwachung einer Prozessgröße des Mediums, der in den Schacht einsetzbar ist, wobei die Leitung an ihrem in den Schacht mündenden Endabschnitt eine auswechselbare Düse aufweist, durch die ein in der Leitung fließendes Medium den Sensor anströmt, und wobei die Anströmung mittels der Ausgestaltung und/oder der Ausrichtung der Düse in dem Endabschnitt in Abhängigkeit von dem Medium und/oder von dem Sensor einstellbar ist

The object is achieved by a modular sensor arrangement, comprising:

• - a fitting that
  • - a shaft and
  • --a conduit disposed within the fitting for guiding a flowable medium, wherein the line opens with an end portion of the conduit into the shaft, and
• - One, in particular electrochemical, sensor for determining and / or monitoring a process variable of the medium which can be inserted into the shaft, the conduit having at its end opening into the shaft a replaceable nozzle through which a medium flowing in the conduit flows against the sensor, and wherein the flow by means of the configuration and / or the orientation of the nozzle in the end portion in dependence on the medium and / or the sensor is adjustable

The invention solves the abovementioned technical problem by virtue of the fact that the modular sensor arrangement can be used for any media, in particular with arbitrary flows within the line of the fitting, and / or for any elongated sensors for determining and / or monitoring a process variable of the medium. The flow is individually adjustable by means of the design and / or orientation of the interchangeable nozzle and thereby tunable to the sensor and / or the medium, in particular as a function of the sensor and / or the medium optimized. Depending on e.g. the properties of the medium and the design of the sensor, the optimally configured nozzle can be selected and / or the nozzle can be optimally aligned in the end portion.

The term "orientation" of the nozzle in the end portion refers both to the angle at which the nozzle flows against the sensor (i.e., an angle of attack) and also to what extent the nozzle is pushed into the end portion. As a result, for example, the distance between the end face of the sensor and the end face of the nozzle facing the end face changes.

The properties of the medium include e.g. a respective predetermined interval, in which a physical size of the flowable medium such as the viscosity, density, flow, temperature, etc. are. In particular, the flow is relevant here, as this usually strongly influences the flow. If small volume flows of e.g. below 10 l / h in the line of the valve before, by means of the design of the nozzle even for these, the above-mentioned required minimum inflow can be achieved. Such low volume flows are often desirable with the aim of sparing handling of the medium. By means of the nozzle, it is thus possible to reduce an unnecessarily large flow in a flow-through fitting with a line designed as a bypass. Another property of the medium is its composition, for example a known chemical composition and / or if the medium contains the sensor-stressing particles, e.g. abrasive particles such as sand.

The design of the sensor determines, for example, the insertion depth and the sensitivity of the sensor. As "sensitivity" of the sensor is in the context of this application on the one hand, the sensitivity of the sensitive component to the analyte contained in the medium such as the sensitivity of the above-mentioned sensitive membrane, on the other hand, the sensitivity of the sensor to damage by contained in the medium and the Sensor stressing particles called.

Depending on the properties of the medium and the sensor thus results in each case an optimal nozzle with an optimized flow.

The optimization of the flow takes place, for example, based on experience with predetermined applications and / or sensors. Alternatively, the design of a nozzle required for an optimized flow is determined within the scope of experimental investigations and / or calculations. In the case of calculations, in particular, e.g. a particular flow model and / or a numerical model, such as an FEM model.

In one development of the invention, an end region of the nozzle faces an end face of the sensor. The end face of the sensor is, for example, the aforementioned sensitive membrane of an electrochemical sensor.

In one embodiment of the invention, the flow of the sensor through the medium based on the shape of the nozzle, based on a cross-sectional area of the nozzle in the end region, based on a distance between the end portion of the nozzle and the end face and / or based on an angle of attack of the nozzle in relation to the end face of the sensor adjustable.

The distance between the end region of the nozzle and the end face is on the one hand based on the design of the nozzle, i. over its length, adjustable, on the other hand, as already mentioned, about its orientation in the end section.

The angle of attack is defined such that an incident flow in a direction perpendicular to the end face (i.e., parallel to a surface normal of the end face) corresponds to an angle of attack of 90 °.

In one embodiment of this development, the angle of attack of the nozzle with respect to the end face by means of an arranged between the nozzle and the end portion of the line alignment is adjustable. In particular, the alignment element is a ball joint. However, the alignment element can also be a displaceably mounted aperture or an adjustable hose. The latter can be aligned, for example, by means of a guide element.

In one embodiment of the invention, the sensor can be inserted into the shaft with a predetermined insertion depth.

In one embodiment of the invention, the shaft and / or the sensor are / is elongate.

In one embodiment of the invention, the shaft and / or the sensor are in particular substantially cylindrical.

In one embodiment of the invention, the nozzle is substantially cylindrical.

In a preferred development of the invention, a particle filter is arranged in the nozzle.

In a particularly preferred embodiment of this development, the particulate filter is replaceable. This can be done on the one hand by a clogging of the particulate filter required replacement of the particulate filter. Replacement of the particulate filter without simultaneous replacement of the nozzle is e.g. advantageous if due to a sensor exchange only an adaptation of the particulate filter, but not the nozzle required, for example because both sensors have the same insertion depth but a different sensitivity to different abrasive particles.

In a further preferred development of the invention, the line has a section leading past the nozzle, by means of which a portion of the medium can be conducted past the nozzle. This embodiment is particularly advantageous if there is a sufficiently large flow in the bypass for the required minimum inflow. In this case, the bypassed portion of the medium does not come into contact with the sensor and can flow through the fitting.

In one embodiment of this development, the proportion of the medium conducted past the nozzle can be adjusted by means of a valve. The valve is, for example, a ball valve, a needle valve or a slider.

In a further embodiment of the invention, an outflow is arranged in the shaft, via which medium which has flowed through the nozzle into the shaft can again be diverted from the shaft.

In a further embodiment of the invention, the line is only temporarily traversed by medium. In this case, the fitting has a medium detector arranged on the line, with which the presence of medium in the line can be detected. This advantageously provides additional functional safety of the small flow sensor array, e.g. Failure of the sensor signal can be correlated with the absence of the medium in the conduit. The medium detector is thus a sensor for detecting the presence of a medium in the line.

In a preferred embodiment of this development, the medium detector is arranged adjacent to the nozzle.

In a further preferred embodiment of this development, the medium detector is an inductive and / or capacitive conductivity sensor.

• 1: Experimentelle Untersuchungen der Anmelderin mit einer erfindungsgemäßen Sensoranordnung;
• 2a,b: Schnittansichten des Einflusses des Anströmwinkels für unterschiedliche Sensoren einer erfindungsgemäßen Sensoranordnung;
• 3: Eine Schnittansicht einer Ausgestaltung einer erfindungsgemäßen Sensoranordnung;
• 4: Eine Schnittansicht einer weiteren Ausgestaltung einer erfindungsgemäßen Sensoranordnung.

The invention will be explained in more detail with reference to the following, not to scale figures, wherein like reference numerals designate like features. If it requires the clarity or it appears otherwise useful, is omitted reference numerals already mentioned in subsequent figures. It shows:

• 1 : Experimental investigations by the applicant with a sensor arrangement according to the invention;
• 2a, b : Sectional views of the influence of the angle of attack for different sensors of a sensor arrangement according to the invention;
• 3 : A sectional view of an embodiment of a sensor arrangement according to the invention;
• 4 : A sectional view of a further embodiment of a sensor arrangement according to the invention.

1 shows experimental investigations of the applicant with a fitting 1 , At the fitting 1 it is a flow-through fitting, with which the process size of the medium 4 in a bypass designed as a conduit 3 with one in a shaft 2 (see. 2 to 4 ) of the fitting 1 used electrochemical sensor 5 is determined and / or monitored.

In the electrochemical sensor 5 it is an amperometric disinfection sensor, with which in the bypass line 3 the chlorine content (or the content of another previously added disinfectant) of the medium 4 is determined and / or monitored. In the case of amperometric sensors, a sensor current is output as the measurement signal representing the process variable. The sensor current measured in Applicant's experimental studies is for a constant concentration of the analyte in the medium 4 for each different volume flows between 10 and 75 l / h as the top dashed line D in 1 applied.

The sensor current at constant analyte concentration and at the same time changing volume flow rates is considered the line S1 in the graph in 1 applied. For a fixed nozzle 6 which is not specific to the sensor 5 (please refer 2-4 ), is matched, even with constant analyte concentration an unwanted, very strong dependence of the sensor current of each existing volume flow. This is due to a non-optimized flow of the sensitive membrane at the frontal area 51 of the sensor 5 (see. 3 and 4 ) through the medium 4 conditionally, since the observed change in the sensor current is essentially due to a change in the volume flow. For example, for smaller volume flows below 30 l / h, this is not the minimum inflow of the sensitive membrane of the amperometric disinfection sensor mentioned above.

For a given sensor 5 eg with a given insertion depth HSENS in the shaft 3 is used and a given medium 4 With a volume flow from a certain interval, the flow can be optimized by means of the modular sensor arrangement according to the invention. This is shown schematically by the other lines S2 to S6 below the topmost solid line S1 in 1 shown. Shown is the sensor current for measurements, in each of which differently configured nozzles 6 , ie with different shapes, diameters, nozzle lengths, etc., were used

The experimental investigations of the applicant show that by means of the suitable choice of the design of the nozzle 6 reduce the unwanted dependence of the sensor current on the volume flow. For a nozzle 6 with an optimized flow (lowest solid line S6 ), the sensor current for all volume flows from the observed interval is substantially constant. In the optimization of the flow shown here, the undesired influence of the volume flow on the measurement signal described above is eliminated, so that the sensor has a constant sensitivity, regardless of the respective volume flow from the observed interval.

An optimum flow for each sensor in a fitting can continue to have an angle of attack α include. This is in the sectional view in 2a and 2 B shown in more detail

The sensor 5 and the shaft 2 are here designed essentially as cylindrical, so that the in 2a with a certain predetermined insertion depth HSENS in the shaft 2 used sensor 5 surrounds an annular gap. In the event that the medium 4 For example, in addition to the analyte (here chlorine) also contains abrasive sand particles is a vertical flow (ie with a flow angle α of 90 °) of the end face 51 of the sensor through the medium 4 undesirable, otherwise the on the front surface 51 of the sensor 5 arranged sensitive membrane can be damaged by abrasion. Due to the orientation of an end area 61 (not shown here, see 3 ) of the nozzle 6 in relation to the sensor 5 becomes an angle of attack α set greater than 90 °.

In 2a is an example of the respective medium 4 and for the sensor 5 with a predetermined insertion depth HSENS optimized angle of attack α shown a compromise between a sufficient sensitivity of the sensitive membrane, ie, regardless of the respective volume flow (see. 1 , bottom line S6 ), and avoidance of a membrane potentially damaging vertical flow was found.

Will now be in the same faucet 1 another sensor 5 with a different, in particular shorter insertion depth HSENS used, see 2 B , so can the previously optimized angle of attack α due to the increased distance hds between nozzle 6 and sensor 5 no longer be optimal, because now too much of the medium 4 on the sensitive membrane flows past the sensor through the annular gap. The modular sensor arrangement according to the invention advantageously permits an exchange of the nozzle and / or a tracking of the alignment of the nozzle 6 , Thus, it is possible to respond flexibly to such a sensor exchange. Independent of the respective sensor 6 or its insertion depth HSENS is still the same universal fitting 1 usable.

The inventive modular sensor arrangement is in a first embodiment in 3 and in a second embodiment in 4 shown in more detail in a sectional view.

3 shows the fitting 1 with the outside of the shaft 2 the fitting 1 with the specified insertion depth HSENS used amperometric disinfection sensor. In one inside the fitting 1 arranged opening of the shaft 2 leads an end section 31 a bypass line 3 , The replaceable nozzle 6 with a certain shape, length and cross-sectional area QF is with the end section 31 the line 3 and the shaft 2 connected. By means of the replaceable nozzle 6 can be the one for the respective medium 4 and the respective sensor 5 optimal flow in the valve 1 be set. This can advantageously the same universally applicable Armatur1 for a variety of differently designed sensors 5 and use cases. After the medium 4 with the means of the nozzle 6 certain flow the end face 51 the flow of the sensor is the medium 4 through a drain 10 from the shaft 2 passed, which at an upper end of the shaft 2 is arranged.

Depending on the application, the in 3 shown particulate filter 8th in the nozzle 6 be used, with a share of in the medium 4 filtered out particles is filtered out. The particles are, for example, the abovementioned abrasive particles or particles which accumulate on the sensitive membrane and potentially secrete the membrane. It is preferably an exchangeable particle filter 8th , so that eg when changing the medium 4 or adding the particulate filter 8th Here, too, can be reacted flexibly, without a complete replacement of the nozzle 6 is required.

In 4 the detail of a sectional view of a further embodiment of the sensor arrangement according to the invention with an amperometric disinfection sensor is shown. The angle of attack α determining orientation of the nozzle 6 with respect to the sensor is here by means of an alignment element 7 set, which is between the end section 31 the line 3 and the nozzle 6 is arranged. The alignment element 7 is designed here as a ball joint. The length of the nozzle 6 determines the distance hds between the end area 61 the nozzle 6 and the nozzle 6 facing end face 51 of the sensor 5 ,

Furthermore, in this embodiment, the valve 1 one with a valve 9 with the line 3 connected and at the nozzle 6 passing section 32 on. For very large volume flow rates, eg above 30 to 60 l / h, the valve can 9 be opened so that through this section 32 a share of the medium 4 flows back through the valve from the bypass. As a result, very large volume flows essentially do not cause a changed flow of the sensor 5 , with which an exchange and / or readjustment of the nozzle 6 would have to be reacted.

In some flow fittings, the case occurs that the line 3 not essentially continuous, but only temporarily from the medium 4 is flowing through. To increase the redundancy is in this case in an advantageous embodiment in the line 3 adjacent to the nozzle 6 an additional media detector 11 on the line 3 arranged to detect the presence of medium 4 in the pipe 3 is designed. The medium detector 11 is designed here as an inductive conductivity sensor. The measuring signal of the medium detector 11 can be correlated with the measuring signal of the amperometric disinfection sensor. By means of this correlation it can be determined whether, for example, an abrupt change of the measuring signal of the amperometric disinfection sensor by a mere change, such as a slowing down of the volume flow or by the absence of medium 4 in the pipe 3 caused. In this embodiment, therefore, it is thus additionally monitored whether the optimal flow for the application, ie independent of the volume flow that occurs in each case in the application, actually also exists.

Notwithstanding the fact that the invention has been explained in the context of an amperometric disinfection sensor, the invention is of course not limited to this embodiment, but is also relevant to sensor arrangements with a sensor of a different type of sensor. In particular, the invention is applicable in connection with all sensors which are at their nozzle 6 facing end face having a sensitive component, with the one with the concentration of an analyte in the medium 4 correlated measured variable is determined and / or monitored. The sensitive component is, for example, a sensitive end face of an electrochemical sensor, since here there is often a fundamental dependence of the sensor signal on that through the nozzle 6 mitbestimmte flow shows. Examples of such electrochemical sensors with a sensitive end face are potentiometric sensors, in particular ion-selective electrodes such as pH electrodes with a sensitive membrane, but also ISFET sensors. In the latter case, the sensitive end face may, for example, be understood to be its sensitive semiconductor insulator layer. Other examples include optical or amperometric oxygen sensors ("dissolved oxygen" or "DO" sensors) or turbidity sensors.

LIST OF REFERENCE NUMBERS

1

fitting

2

shaft

3

management

31

End section of the pipe

32

at the nozzle passing section of the line

4

medium

5

sensor

51

Face of the sensor

6

jet

61

End portion of the nozzle

7

aligning

8th

particulate Filter

9

Valve

10

outflow

11

medium detector

HSENS

predetermined insertion depth

QF

Cross-sectional area of the nozzle

hds

Distance between nozzle and sensor

α

angle of attack

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102008039465 A1 [0003]

Claims (15)

Modular sensor arrangement comprising: - a fitting (1), the a shaft (2) and a conduit (3) arranged within the fitting (1) for guiding a flowable medium (4), the conduit (3) opening into the shaft (2) with an end portion (31) of the conduit (3), and - One, in particular electrochemical, sensor (5) for determining and / or monitoring a process variable of the medium (4) which is insertable into the shaft (2), wherein the line (3) at its end opening into the shaft (2) (31) has a replaceable nozzle (6) through which flows in the conduit (3) flowing medium (4) to the sensor (5), and wherein the flow by means of the design and / or the orientation of the nozzle (6) in the end portion (31) in dependence on the medium (4) and / or by the sensor (5) is adjustable. Modular sensor arrangement according to Claim 1 wherein an end portion (61) of the nozzle faces an end surface (51) of the sensor (5). Modular sensor arrangement according to Claim 1 or 2 , wherein the flow of the sensor (5) through the medium (4) - based on the shape of the nozzle (6), - based on a cross-sectional area (QF) of the nozzle (6) in the end region (61), - on the basis of a distance (hds ) between the end region (61) of the nozzle (6) and the end face (51) of the sensor (5) and / or - based on an angle of incidence (a) of the nozzle (6) with respect to the end face (51) of the sensor (5 ) is adjustable. Modular sensor arrangement according to at least one of the preceding claims, wherein the alignment of the nozzle (6) with respect to the end face (51) of the sensor (5), in particular the angle of attack (α), by means of a between the nozzle (6) and the end portion of the Line (3) arranged alignment element (7), in particular by means of a ball joint, is adjustable. Modular sensor arrangement according to at least one of the preceding claims, wherein the sensor (5) can be inserted into the shaft (3) with a predetermined insertion depth (hsens). Modular sensor arrangement according to at least one of the preceding claims, wherein the shaft (2) and / or the sensor (5) are elongated in particular substantially cylindrical / is. Modular sensor arrangement according to at least one of the preceding claims, wherein the nozzle (6) is substantially cylindrical. Modular sensor arrangement according to at least one of the preceding claims, wherein a particle filter (8) is arranged in the nozzle (6). Modular sensor arrangement according to Claim 8 , wherein the particle filter (8) is replaceable. Modular sensor arrangement according to at least one of the preceding claims, wherein the conduit (3) has a section (32) leading past the nozzle (6), by means of which a portion of the medium (4) can be conducted past the nozzle (6). Modular sensor arrangement according to Claim 10 in which a valve (9) is arranged in the section (32) which leads past the nozzle (6), and wherein the proportion of the medium (4) guided past the nozzle (6) can be adjusted by means of the valve (9). Modular sensor arrangement according to at least one of the preceding claims, wherein an outflow (10) is arranged in the shaft (2), via which medium (4) which has flowed into the shaft (4) through the nozzle (6) again out of the shaft (2). is derivable. Modular sensor arrangement according to at least one of the preceding claims, wherein the conduit (3) is only intermittently flowed through by medium (4), and wherein the fitting has a on the conduit (3) arranged medium detector (11), with the presence of medium ( 4) in the line (3) can be detected. Modular sensor arrangement according to Claim 13 wherein the medium detector (11) is disposed adjacent to the nozzle (6). Modular sensor arrangement according to Claim 13 or 14 wherein the medium detector (11) is an inductive and / or capacitive conductivity sensor.

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