Online Compact Measuring Device

Abstract

The present invention relates to an in-line compact measuring device (1), for example for optical measurement, the in-line compact measuring device (1) comprising: a housing (2) having a process connection (6) intended to be connected to a complementary process vessel connection of the process connection (6); at least one sensor assembly arranged in the housing; and a measurement circuit (8) connected to the sensor assembly and arranged in the housing (2); wherein the in-line compact measuring device (1) has at least one fluid line (9) in thermally conductive contact with at least one housing wall of the housing (2), the fluid line being connectable to a cooling fluid source arranged outside the housing (2).

Description

Field of the Invention

[0001] The present invention relates to an online compact measuring device which can be set, for example, for optical measurement. The online compact measuring device can include, for example, an online spectrometer. Background Art

[0002] In process measurement technology, measuring devices are used, among other things, to determine the properties of process media and to use the acquired measurement data to monitor, control, and / or adjust processes. Measuring devices can have probes that are integrated into the process and that generate raw measurement signals and output them to remote electronics for further processing and evaluation. However, there are also compact measuring devices (such as "intelligent" sensors) that have a single housing in which sensor components for generating raw measurement signals are bundled with an electronic evaluation unit for further processing of the raw measurement signals. The housing of such a compact measuring device can be integrated into the wall of a process vessel through a process connection, which can be, for example, a pipeline for transporting gas or liquid, a reactor, a fermenter, or a storage container.

[0003] Optical measuring devices are used, for example, for various measurement tasks, such as for the qualitative or quantitative determination of one or more analytes, for the determination of sum parameters, or for the determination of particle loading and / or turbidity in a process medium. The process medium can be, for example, a gas or a liquid. An optical measuring device is configured to radiate measurement radiation into the process medium, receive at least a portion of the radiation that has been altered after interacting with the process medium, and generate a measurement signal representing the property to be determined or being measured based on the received radiation. Depending on the application, the altered radiation can be radiation that is transmitted, reflected, emitted, and / or scattered by the luminescence of the components of the process medium.

[0004] Optical measuring devices used in process measurement technology are, for example, scattered light sensors such as turbidity sensors, photometers, spectrometers, and / or spectrophotometers. The measuring device typically has a housing with a process connection that can be attached to a process vessel to integrate the measuring device into the process vessel for in-process measurement. Such an integrated measuring device is also referred to as an in-line measuring device. If the housing of the optical measuring device is connected to the process vessel, one or more measuring windows facing the interior of the process vessel can be integrated into the housing. Via the one or more measuring windows, the measuring device can radiate measuring radiation into the process vessel and receive the transformed radiation from the process vessel. The optical measuring device also includes optical components (i.e., one or more radiation sources and one or more detectors for measuring radiation), which are configured to receive the transformed radiation and generate a measurement signal and / or measurement data based on the received radiation. Possible detectors are, for example, photodiodes, photodiode arrays, or spectrometers. The optical measuring device also has a measuring circuit, for example in the form of a measuring electronics unit, to generate and possibly further process the measurement signal or measurement data. The measuring circuit can be used to control the one or more radiation sources and process the measurement signal or measurement data generated by the detector. The measuring circuit can also be set to determine the measured value of the measured quantity to be determined based on the measurement signal and output them via an interface to a higher-level unit (such as a process control unit, a measurement transducer, an operating unit, or another data processing unit).

[0005] The optical in-line measuring device can have a probe and a housing remote from the probe. In this case, the probe can have the aforementioned process connection and means for coupling the measuring radiation into the process medium and for coupling out the altered radiation from the process medium, such as the aforementioned measuring windows. In some optical measuring devices, especially in turbidity measuring devices or photometer measuring devices, the optical components can be at least partially arranged in the probe. Optionally, the probe can also contain part of the measuring circuit. In these cases, the remote housing can contain at least the part of the measuring circuit for further processing the signals of the circuitry integrated in the probe. In these cases, the probe is connected via a cable for transmitting analog or digital measurement signals to the circuitry arranged in the remote housing.

[0006] In other optical measuring devices, especially spectrometers, all optical components and measuring circuitry in the optical unit are usually arranged in a remote housing. In this case, the probe is connected via light guides to the optical components in the remote housing, which light guides direct the measuring radiation from a radiation source arranged in the housing to the probe in order to couple the measuring radiation into the process medium and direct the converted radiation coupled into the probe back to a detector arranged in the remote housing.

[0007] There are also optical compact measuring devices which are characterized in that a measuring window, optical components and measuring circuitry are arranged together in a single housing (which can be attached to a process vessel via a process connection), such that the means for coupling in and coupling out radiation (such as the measuring window) face the interior of the process vessel in order to couple in and couple out radiation.

[0008] Optical in-line compact measuring devices, especially spectrometric in-line compact measuring devices, can in principle be used very generally, since based on suitable chemometric models, spectrometric data or spectrophotometric data can be used to determine a plurality of measured variables, such as the concentration of a large number of analytes. However, especially in the case of spectrometers, the relatively complex optical and electronic systems of such measuring devices are temperature-sensitive, such that the construction with a probe and a remote housing (in which the optical components and sensor circuitry are accommodated) described above has so far been preferred for such optical measuring devices. Summary of the Invention

[0009] Accordingly, it is an object of the present invention to provide an in-line compact measuring device which can also be used for measurements at high temperatures.

[0010] The in-line compact measuring device according to the present invention comprises:

[0011] a housing, which is for example a multi-part housing and which has a process connection, wherein the process connection is intended to be connected to a complementary connection of a process vessel;

[0012] at least one sensor assembly, which is arranged in the housing; and

[0013] a measuring circuit, which is connected to the sensor assembly and is arranged in the housing,

[0014] wherein the in-line compact measuring device has at least one fluid line in thermally conductive contact with at least one housing wall of the housing, which fluid line can be connected to a cooling fluid source arranged outside the housing.

[0015] During operation of the compact measuring device, a cooling fluid (e.g., a gas or a liquid such as water) can flow through the fluid line and thus cool the housing in order to protect temperature-sensitive components, in particular the sensor assembly and / or the measuring circuit. The fluid line can be integrated into the housing.

[0016] The sensor assembly is used to acquire a primary measurement signal. For example, the sensor assembly can form a measurement sensor for optical or electrochemical measurements. The sensor assembly can also have a temperature sensor. The compact measuring device can be suitable for optical measurements, for example, and thus will have a sensor assembly with optical components, such as at least one radiation source and at least one radiation receiver or detector. These can be connected to the measuring circuit. The measuring circuit can be configured to control the radiation source to emit measurement radiation. The measuring circuit can also be configured to receive, record, optionally also amplify and forward and / or process the measurement signal of the radiation receiver. The radiation receiver can be configured to receive the radiation emitted by the radiation source and changed in the measurement medium and generate a signal based on one or more characteristics of the changed radiation.

[0017] The radiation source can include one or more LEDs or broadband light sources, such as a UV lamp. The radiation receiver can be a detector including one or more photodiodes or a photodiode array. The detector can also be a spectrometer.

[0018] In a possible refinement, the in-line compact measuring device can have means for coupling radiation from the housing into the measurement medium accommodated in the process vessel and / or means for coupling radiation from the measurement medium into the housing. Thus, the in-line compact measuring device can have, for example, at least one measurement window integrated into the housing wall. The at least one measurement window can be used to couple radiation out of the housing from the radiation source or to couple it into the housing to reach the radiation detector. Alternatively, an optical fiber routed through the housing wall or other means for coupling and coupling out radiation can also be used for this purpose.

[0019] In an advantageous refinement, the fluid line is designed as a fluid channel integrated in the housing. The housing can be made of steel.

[0020] In the housing, an electronics compartment can be formed, which extends from the first end of the housing in the direction of the process connection, and the measuring circuit is arranged in this electronics compartment.

[0021] Wherein, the fluid line is arranged outside the electronics compartment, on the side of the electronics compartment facing away from the first end of the housing.

[0022] If the process connection of the in-line compact measuring device is connected to a process vessel, fluid lines, in particular fluid channels, can be arranged between the electronics compartment and the region of the in-line compact measuring device intended to be in contact with the measuring medium accommodated in the process vessel. For example, the flow direction of the fluid flowing through the fluid line (such as the aforementioned fluid channel) can extend in a plane extending between the electronics compartment and the process connection.

[0023] In an improvement, the measurement circuit can be arranged on a circuit board disposed in the electronics compartment. The measurement circuit can be used to operate the measuring device and determine the measured value. The sensor assembly can also be arranged in the electronics compartment. If the in-line compact measuring device is designed as an optical measuring device, the optical components of the sensor assembly can be arranged in the electronics compartment, for example, on a carrier.

[0024] For explosion protection and / or to prevent moisture or water from penetrating, the electronics compartment can be tightly sealed relative to the environment such that no mass transfer, such as gas or liquid transfer, occurs between the electronics compartment and the environment, or at least such mass transfer occurring between the electronics compartment and the environment is so small that the mass transfer is not sufficient to dissipate heat from the electronics compartment, in particular from the measurement circuit and / or the sensor assembly, to an extent sufficient to protect the temperature-sensitive parts of the sensor assembly and / or the measurement circuit.

[0025] The electronics compartment can have a substantially cylindrical side wall, and at least one cooling plate is arranged in the electronics compartment, which cooling plate extends substantially along the side wall of the electronics compartment and is in thermally conductive contact with the fluid line. The cooling plate can be bent into a hollow cylindrical shape and at least partially surround the sensor assembly, such as a carrier attached to at least a part of the sensor assembly. Optionally, the cooling plate can additionally at least partially surround the circuit board having at least a part of the measurement circuit.

[0026] The cooling plate can be formed of metal, such as formed of copper, silver, gold or aluminum. Alternatively, instead of the cooling plate, heat pipes can be used to cool the electronics compartment.

[0027] A carrier can be arranged in the electronics compartment, to which at least a part of the measurement circuit and at least a part of the sensor assembly (such as the optical components of the measuring device mentioned above) are attached. If the measuring instrument has at least one radiation source and at least one detector, these can be attached to the carrier. As already mentioned, the detector can be a spectrometer. The radiation can be conducted from the radiation source to the device for coupling and / or coupling out the radiation, such as a measurement window, through an optical fiber. The radiation that has been changed in the measurement medium outside the housing can be coupled back into the housing via the device for coupling and / or coupling out the radiation (such as a measurement window) and can be conducted to the detector through an optical fiber.

[0028] In a possible improvement, the sensor assembly may have at least one radiation source, wherein the radiation source is attached to an additional cooling plate that is in thermally conductive contact with the fluid pipeline. The additional cooling plate with the radiation source may be at least partially surrounded by the aforementioned cooling plate, which is, for example, bent into a hollow cylindrical shape. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Hereinafter, the present invention will be described in more detail using the exemplary embodiments shown in the drawings. Shown below are:

[0030] Figure 1 A schematic representation of an optical on-line compact measuring device; and

[0031] Figure 2 Through Figure 1 A schematic representation of a longitudinal section of the on-line compact measuring device shown in DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] Figure 1 An optical on-line compact measuring device 1 is shown, which has a spectrometer in this example. The on-line compact measuring device 1 is also shown in the longitudinal section in Figure 2 The same reference numerals in both figures denote the same components of the on-line compact measuring device 1. The on-line compact measuring device 1 has a housing 2 made of steel, which is designed to be substantially cylindrically symmetric about a hypothetical central cylindrical axis Z in this example. The housing 2 may be formed by a plurality of individual parts.

[0033] The front end of the housing 2 is provided for contact with the process medium. This region is also referred to as the medium contact region hereinafter. A transparent small container 3 for transmission measurement is formed in this region. The transparent small container 3 has a first measurement window 4 and an opposite second measurement window 5. Measurement radiation can leave the housing 2 through the first measurement window 4, and radiation that has been changed by interaction with the process medium can enter the housing 2 through the opposite second measurement window 5.

[0034] The housing 2 has a process connection 6, which can be attached to a complementary connection of a process container (such as a reactor, a fermenter, or a pipeline). The region of the housing 2 arranged on the side opposite to the transparent small container 3 of the process connection 6 is not in direct contact with the process medium. However, via the housing wall, it is in thermally conductive contact with the medium contact region of the housing 2.

[0035] The housing 2 encloses an electronic device compartment 7 at its rear end, and the electronic device compartment 7 extends from the rear end of the housing 2 in the direction of the process connection 6 and away from the process. The electronic device compartment 7 houses a measurement circuit in the form of a measurement electronic device unit, which is inFigure 2 is symbolically shown in the form of a circuit board 8. In addition, the electronic device compartment 7 houses the optical components of the measuring device, in this example a radiation source (which emits radiation in the UV / visible range of the electromagnetic spectrum) and a UV / visible spectrometer. The radiation can be conducted from the radiation source within the housing 2 to the first measuring window 4 via an optical fiber. The converted radiation coupled back into the housing 2 via the second measuring window 5 can be guided within the housing 2 to the spectrometer via an optical fiber. The measuring electronics unit is designed to control the radiation source and the spectrometer, which is used to acquire the absorption spectrum of the process medium present in the transparent vial 3, and the measuring electronics unit is designed to further process the captured spectral data by the spectrometer and / or output such data to a higher-level unit connected to the online compact measuring device 1. The spectrometer and the measuring circuit can be attached to a carrier (not shown in the figure) arranged within the electronic device compartment 7.

[0036] If the process medium contacting the medium contact region of the housing 2 has a high temperature, due to the compact design of the online compact measuring device 1, not only will the region of the housing 2 in contact with the medium be heated, but also, by heat conduction through the housing 2 made of steel, it will also be possible to heat the region of the housing 2 arranged above the process connection 6. This endangers the temperature-sensitive optical components and temperature-sensitive circuit elements of the measuring circuit.

[0037] Therefore, a fluid channel 9 that can be connected to a cooling fluid source arranged outside the housing 2 is formed in the housing 2, in the region between the electronic device compartment 7 and the process connection 6, and thus also between the electronic device compartment 7 and the medium contact region of the online compact measuring device 1. For this purpose, the fluid channel 9 has an inlet opening 10 and an outlet opening 11. For example, the cooling fluid can be water. In the example shown here, the fluid channel 9 has a rectangular cross-section and extends annularly around the (imaginary) axis Z of the housing 2. The fluid channel 9 also extends in a (imaginary) plane perpendicular to the axis Z between the medium contact region and the electronic device compartment 7.

[0038] If, for example, water is conducted through the fluid channel 9 as a cooling medium, then even for high process temperatures, the temperature within the electronic device compartment 7 will remain below the threshold that is critical for the temperature-sensitive components of the measuring circuit and / or the optical components.

[0039] In a particularly advantageous refinement of the online compact measuring device 1 shown here, as Figure 2As shown, in addition to the fluid channel 9, as a further measure, a cooling plate 12 for dissipating heat from the electronic device compartment 7 is present within the housing 2. In the exemplary embodiment shown here, this cooling plate 12 is made of copper. The cooling plate 12 is substantially bent into a hollow cylindrical shape and is arranged concentrically with respect to the common axis Z of the housing wall of the electronic device compartment 7 formed in the housing 2. The cooling plate 12 is screwed onto the housing shoulder above the fluid channel 9. Thus, the cooling plate 12 is in thermally conductive contact with the fluid channel 9.

[0040] In the present example, the cooling plate 12 is designed to be bent around the axis Z into a closed or nearly closed hollow cylinder. In principle, the cooling plate 12 may also not be bent into a complete hollow cylinder, but only bent in an arcuate manner around the axis Z and thus form a cylinder segment covering only a part (e.g., one-third or one-half) of the periphery of the electronic device compartment, for example. Similarly, in this improvement, it is also advantageous if the cooling plate 12 extends over the entire length of the electronic device compartment 7 and is in thermally conductive contact with the fluid channel 9.

[0041] However, it is particularly advantageous if the cooling plate 12 has as large an area as possible. To protect the measuring electronics accommodated in the electronic device compartment 7 from ambient heat, a closed hollow cylindrical cooling plate 12 is preferred.

[0042] The use of the cooling plate 12 is advantageous at high process temperatures and / or ambient temperatures in order to sufficiently dissipate heat from the tightly sealed electronic device compartment so that the measuring electronics and / or optical components are not damaged. As shown by simulations and measurements, in the absence of the cooling plate 12, warm air can rise upward within the electronic device compartment 7 and remain there, while cold air accumulates further below in the region of the fluid channel 9. To prevent water ingress or prevent explosions, the housing 2 surrounding the electronic device compartment 7 can be tightly closed so that no mass exchange with the environment occurs, and this alone is sufficient to cool the components arranged in the electronic device compartment 7.

[0043] On the one hand, the interior of the electronic device compartment 7 is thermally insulated from the shell wall of the housing 2 heated by ambient heat through thermal contact with the process contact area of the housing 2 by means of the cooling plate 12. On the other hand, the heat generated in the electronic device compartment 7 is effectively dissipated to the fluid channel 9. Due to the thermal insulation by means of the cooling plate 12, the temperature within the electronic device compartment remains low. Thus, it can be seen that by using the cooling plate 12, the operation of the in-line compact measuring device 1 is possible at high ambient temperatures (e.g., up to 60 °C) despite having sensitive components.

[0044] As an additional measure for dissipating heat from the electronic device compartment 7, a radiation source arranged in the electronic device compartment 7 can be attached to an additional cooling plate (not shown in the figure). The cooling plate can be made of copper, for example, and can be thermally connected to the fluid channel 9 via the housing 2. In this way, the heat generated by the radiation source can be dissipated. The additional cooling plate can be screwed to the housing 2, for example, in the region of the fluid channel 9.

[0045] The invention has been described herein with respect to a spectrometer measuring device which is designed as an online compact measuring device for absorption measurements in the UV / visible light spectral range. However, the invention can equally well be used very similarly for other optical online measuring devices which can be used for measuring NIR or MIR spectra, for Raman spectroscopy, as a photometer or as a turbidity sensor. The invention can also advantageously be applied to online measuring devices which do not operate on the basis of an optical measuring principle and which have a temperature-sensitive measuring circuit integrated in the housing together with the measuring sensor.

Claims

1. An in-line compact measuring device (1), comprising: a housing (2), comprising: - a front end and a rear end, the front end being arranged for contact with a process medium, wherein the housing (2) is cylindrical about an imaginary axis (Z) which extends from the front end to the rear end; - the housing (2) at the front end has a process connection (6), the process connection (6) being intended to connect the in-line compact measuring device (1) to a complementary process vessel connection; and - an electronics compartment (7) located at and extending from the rear end in the direction of the process connection (6), the electronics compartment (7) having a cylindrical side wall; at least one sensor assembly, the at least one sensor assembly being arranged in the housing (2); a measurement circuit, the measurement circuit being connected to the sensor assembly and being arranged in the electronics compartment (7) of the housing (2); a cylindrical cooling plate (12), the cooling plate (12) being arranged within the electronics compartment (7), wherein the cooling plate (12) surrounds the imaginary axis (Z) and is arranged along the side wall of the electronics compartment (7); and a fluid line, the fluid line being integrated in the housing (2) and being located between the process connection (6) and the electronics compartment (7), wherein the fluid line includes an inlet opening (10) and an outlet opening (11) in the housing (2) to enable the fluid line to be connected to a cooling fluid source arranged outside the housing (2), wherein the cooling plate (12) is in thermally conductive contact with the fluid line.

2. The in-line compact measuring device (1) according to claim 1, wherein, the sensor assembly comprises: at least one radiation source, the at least one radiation source being arranged in the housing (2); and at least one radiation receiver, the at least one radiation receiver being arranged in the housing (2) and being connected to the measurement circuit.

3. The in-line compact measuring device (1) according to claim 1 or 2, further comprising at least one measurement window (4, 5) integrated in the wall of the housing (2).

4. The in-line compact measuring device (1) according to claim 1, wherein, the electronics compartment (7) is tightly sealed relative to the environment.

5. The in-line compact measuring device (1) according to claim 1, wherein, the cooling plate (12) is formed of metal.

6. The in-line compact measuring device (1) according to claim 1, wherein, the sensor assembly has at least one radiation source, and wherein the radiation source is attached to another cooling plate in thermally conductive contact with the fluid line.

7. The in-line compact measuring device (1) according to claim 1, wherein, the in-line compact measuring device (1) is for optical measurement.

8. The in-line compact measuring device (1) according to claim 5, wherein, the cooling plate (12) is made of copper, silver, gold or aluminum.

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