OPTICAL PROCESS SENSOR, MEASURING HEAD, MEASURING SYSTEM COMPRISING THE TWO AND METHOD FOR CALIBRATION AND/OR VALIDATION

Abstract

An optical process sensor for measuring at least one measured variable of a medium in a container includes: a housing; a light source in the housing for emitting transmission light; a light detector in the housing for receiving reception light; and an interface including a first mechanical section, which is an integrated part of the housing, and a first optical section having a first path and a first light guide, wherein the first light guide is configured such that transmission light is guided from the light source into the first path via the first light guide and decouples transmission light from the housing, and having a second path and a second light guide, wherein the second light guide is configured such that reception light is coupled into the interior of the housing and guided from the second path to the light detector via the second light guide.

Claims

1. An optical process sensor for measuring at least one measured variable of a medium, the sensor comprising: a housing defining an interior; a light source disposed in the housing and configured to emit transmission light; a light detector disposed in the housing and configured to receive reception light; and a first optical/mechanical interface comprising a first mechanical section, which is configured as an integrated part of the housing, and a first optical section extending from the housing, the first optical section comprising: a first path and a first light guide, wherein the first light guide is configured such that the transmission light is guided from the light source into the first path via the first light guide and such that the transmission light is decoupled from the housing; and a second path and a second light guide, wherein the second light guide is configured such that the reception light is coupled into the interior of the housing and guided from the second path to the light detector via the second light guide.

2. The optical process sensor of claim 1, wherein the optical process sensor is a spectrometer.

3. A measuring head for an optical process sensor and for measuring at least one measured variable of a medium in a container volume, the measuring head comprising: a housing defining an interior and configured to enable the optical process sensor to connect to the container; a second optical/mechanical interface comprising: a second mechanical section configured to be complementary to a first mechanical section of the optical process sensor, wherein the second mechanical section is an integrated part of the housing; and a second optical section configured to be complementary to a first optical section of the optical process sensor and comprising: a third path configured to receive transmission light from the optical process sensor and couples the transmission light into the interior of the housing; and a fourth path configured to receive and guide the transmission light through a region through which the medium flows, wherein the transmission light is converted by the medium into reception light, and wherein the fourth path is further configured to decouple the reception light from the housing.

4. The measuring head of claim 3, wherein the measuring head is configured as an immersion probe.

5. The measuring head of claim 3, wherein the measuring head is configured as a flow probe.

6. The measuring head of claim 3, wherein the measuring head is configured as a calibration and validation device.

7. The measuring head of claim 6, wherein the calibration and validation device comprises a cuvette holder, which includes a mounting for a cuvette, wherein the mounting defines the region through which the medium flows.

8. The measuring head of claim 6, wherein the calibration and validation device comprises a cuvette changer, filter wheel or filter changer.

9. An optical measuring system for measuring at least one measured variable of a medium in a container, the optical measuring system comprising: an optical process sensor comprising: a first housing defining an interior; a light source disposed in the first housing and configured to emit transmission light; a light detector disposed in the first housing and configured to receive reception light; and a first optical/mechanical interface comprising a first mechanical section, which is configured as an integrated part of the first housing, and a first optical section extending from the first housing, the first optical section comprising: a first path and a first light guide, wherein the first light guide is configured such that the transmission light is guided from the light source into the first path via the first light guide and such that the transmission light is decoupled from the first housing; and a second path and a second light guide, wherein the second light guide is configured such that the reception light is coupled into the interior of the first housing and guided from the second path to the light detector via the second light guide; and a measuring head configured for the optical process sensor, the measuring head comprising: a second housing defining an interior and configured to enable the optical process sensor to connect to the container; a second optical/mechanical interface comprising: a second mechanical section configured to be complementary to a first mechanical section of the optical process sensor, wherein the second mechanical section is an integrated part of the second housing; and a second optical section configured to be complementary to a first optical section of the optical process sensor and comprising: a third path configured to receive transmission light from the optical process sensor and couples the transmission light into the interior of the second housing; and a fourth path configured to receive and guide the transmission light through a region through which the medium flows, wherein the transmission light is converted by the medium into reception light, and wherein the fourth path is further configured to decouple the reception light from the second housing, wherein the second optical section accommodates the first optical section as to enable an optical connection to a light path, which includes the light source, the first light guide, the first path, the third path, a deflection element, the fourth path, the second path, the second light guide and the light detector, and wherein the second optical section enables a mechanical connection of the optical process sensor and the measuring head via the first mechanical section and second mechanical section.

10. The optical measuring system of claim 9, wherein: the mechanical connection is releasable; the first mechanical section and the second mechanical section are configured for a screw connection; and the first mechanical section and the second mechanical section comprise complementary bores and/or threads for the screw connection.

11. A method for calibrating and/or validating the optical process sensor of the optical measuring system according to claim 8, the method comprising: removing the optical process sensor from a measuring head, which is configured as a flow probe or an immersion probe; attaching the optical process sensor to a measuring head, which is configured as a calibration and validation device; calibrating and validating the optical process sensor using the calibration and validation device; removing the optical process sensor from the calibration and validation device; and reattaching the optical process sensor to the flow probe or immersion probe.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The embodiments of the present disclosure are explained in more detail with reference to the following figures:

[0048] FIGS. 1a and 1b show an optical process sensor according to the present disclosure in cross-section and side views, respectively;

[0049] FIGS. 2a-2d show an immersion probe embodiment of a measuring system according to the present disclosure;

[0050] FIGS. 3a-3d show a flow probe embodiment of a measuring system according to the present disclosure;

[0051] FIGS. 4a-4e show a cuvette holder embodiment of a measuring system according to the present disclosure;

[0052] FIG. 5 shows an LED sensor embodiment of a measuring system according to the present disclosure; and

[0053] FIGS. 6a-6c show a cuvette holder according to the present disclosure with and without a solids standard.

[0054] In the figures, the same features are identified by the same reference signs.

DETAILED DESCRIPTION

[0055] A measuring system according to the present disclosure in its entirety is denoted by reference sign 100 and is shown, for example, in FIG. 2d. First, the individual components are discussed, namely a process sensor 1 and a measuring head 51.

[0056] FIG. 1a and FIG. 1b show the sensor 1 with the housing 2. The sensor 1 is an optical sensor. Said sensor 1 is, for example, a spectrometer with a light source 3 and a light detector 4. The light source 3 transmits transmission light 5, and the light detector 4 receives reception light 6, which is produced by conversion of the transmission light 5 at the medium to be measured (see below). The light 5 emitted by the light source 3 is thus converted by the medium, for example, absorbed, scattered or fluorescent light is produced. This converted reception light 6 is captured by the detector 4 and converted into an electrical signal.

[0057] The sensor 1 comprises a first optical/mechanical interface 10 including an optical section 11 and a mechanical section 21.

[0058] The mechanical section 21 serves to connect the sensor 1 to the measuring head 51, for example, by screw attachment, wherein corresponding devices, for example, holes, threads or bores 22 and 72, are present. The mechanical section 21 may be an integral part of the housing 2.

[0059] The optical section 11 projects from the housing 2. Said optical section 11 comprises a first path 12 and a first light guide 13, for example, an optical wave guide or a free beam guide, which introduces transmission light 5 from the light source 3 into the first path 12 and then decouples transmission light 5 from the housing 2. Said optical section 11 further comprises a second path 14 and a second light guide 15, for example, an optical wave guide or a free beam guide, which couples reception light 6 into the interior of the housing 2 and guides the reception light 6 from the second path 14 to the light detector 4 via the second light guide 15. The paths 12, 14 include separate, cylindrical extensions, which are, for example, screwed to the housing 2, wherein the optical wave guides 13, 15 are guided in the interior.

[0060] FIG. 2a shows the measuring head 51 in cross-section; FIG. 2c shows measuring head 51 in a side view. FIG. 2b shows the sensor 1 directly next to FIG. 2a. FIG. 2d shows the measuring system 100 in the assembly of sensor 1 and measuring head 51.

[0061] The measuring head 51 comprises a second optical/mechanical interface 60, which includes an optical section 61 and a mechanical section 71.

[0062] The mechanical section 71 serves to connect the measuring head 51 to the sensor 1, for example, by screw attachment, wherein corresponding features, for example, holes, threads or bores 22 and 72, are present. The mechanical section 71 is an integral part of the housing 52.

[0063] In addition, the housing 52 is configured to be connected to a container in which a measuring medium to be measured is located. The housing 52 comprises corresponding connecting means for this purpose. The connecting means can be configured, for example, as a welded or flanged connection, for example, made of stainless steel. However, other embodiments are possible. The container can be, for example, a tank, boiler, pipe, pipeline or the like.

[0064] The second optical/mechanical interface 60 comprises a second optical section 61, which is complementary to the first optical section 11 and configured as a recess in the housing 52. Said second optical section 61 includes a third path 62, which receives transmission light 5, couples it into the interior of the housing 52, and guides it to a deflection element 67. Said second optical section 61 further includes a fourth path 64, which receives transmission light 5 from the deflection element 67, guides it through a region 68 through which the measuring medium flows, wherein the transmission light 5 is converted into reception light 6 by the medium in the region 68 through which the medium flows, and finally decouples reception light 6 from the housing 52 again.

[0065] The deflection element 67 deflects the transmission light 5 by 180° and is designed as a prism.

[0066] The third and fourth paths 62, 64 may be configured as two separate rod-shaped, for example, cylindrical, recesses. The third and fourth paths 62, 64 are configured to be complementary to the first and second paths 12, 14 such that the extensions fit precisely into the recesses. If the sensor 1 and the measuring head 51 are assembled and mechanically fixed via the mechanical sections 11, 61, the two optical sections 11, 61 are positioned in such a way that the transmission light 5 or the reception light 6 are guided by the sensor 1 into the head 51 or vice versa. There are embodiments with lenses 16 (as shown) or windows.

[0067] The transmission light 5 temporarily exits the measuring head 51, passes through the region 68 through which the medium flows, and then enters the housing 52 again at a corresponding location. Transparent windows 66 isolate the interior from the medium (for the sake of clarity, the reference sign points only to the left window). The path 68 through which the medium flows can be arranged in the third or in the fourth path 62, 64.

[0068] FIGS. 2a-2d show an embodiment of the measuring head 51 as an immersion probe. In such an embodiment, the measuring head 51 is placed in the medium to be measured and remains there during a measurement operation. However, the measuring head 51 can also be removed, for example, for maintenance purposes such as changing seals, from the process and from the sensor 1.

[0069] FIGS. 3a-3d are systematically constructed similarly, wherein the measuring head 51 is configured as a flow probe in the embodiment shown. The medium flows through an input 69a and leaves the flow probe again at the output 69b, as shown in FIG. 3c. The region 68 through which the medium flows is located in the interior.

[0070] If a validation or calibration of the sensor 1 becomes necessary or desired, it can easily be removed from the measuring head 51 in the process (e.g., implementation as a flow probe) by releasing the screw connection.

[0071] The measuring head 51 can be configured as a calibration and validation device. This is shown in FIGS. 4a-e, wherein FIGS. 4a-d are initially systematically constructed similarly to FIGS. 2a-2e.

[0072] The sensor 1 is thus removed and the measuring head 51 in the embodiment is attached as a calibration and validation device to the sensor 1, which likewise has a second optical/mechanical interface 60.

[0073] One embodiment of the calibration and validation device is a cuvette holder. The holder 80 into which a cuvette 81 is introduced is located at the region 68 through which the medium flows. The cuvette 81 can be configured as a standard, for example, as a solids standard. The assembled state is shown in FIG. 4d, wherein the cuvette holder is not yet completely installed.

[0074] FIG. 4e shows the embodiment as a cuvette holder with a sensor inserted, wherein only the first optical section 11 is visible. Some components are rendered transparent for clarity to show the assembly, primarily the optical sections 11, 61. The sensor 1 can be calibrated, validated, and adjusted, if necessary, by means of the cuvette holder 51.

[0075] The calibration and validation device can also be configured as a cuvette changer, filter wheel, or filter changer. Various absorptions can be set on the filter wheel so that various situations can be simulated by turning.

[0076] After calibration and/or validation, the sensor 1 may be removed from the calibration and validation device and again connected to the other measuring head, for example, the immersion probe or the flow probe.