Bubble-independent sensor spot, sensor cap containing the sensor spot and sensor containing the sensor cap

Abstract

Method for producing a sensor spot (2) comprising a PTFE layer (1) up to 20 µm thick and in contact with the medium during operation, comprising providing a substrate (3), preferably a glass substrate, more preferably a glass substrate made of quartz glass, Coating the substrate (3) with an analyte-sensitive pigment layer (4) arranged on the medium side, wherein the pigment layer (4) contains at least one luminophoric dye (5), wherein the pigment layer (4) is configured to emit luminescence, wherein the intensity, decay time or phase shift of the luminescence depends on the concentration of the analyte (6) in a measuring medium (7), preferably an aqueous medium, coating the pigment layer (4) with a first silicone layer (8) arranged on the medium side, Coating the first silicone layer (8) with a PTFE polymer layer (1).

Description

[0001] The invention relates to a sensor spot, a sensor cap containing the sensor spot and a sensor containing the sensor cap.

[0002] Optical sensors are sensors based on an optochemical reaction with an analyte from the measuring medium. An optochemical or optical analyte sensor, such as an oxygen sensor or carbon dioxide sensor, is based on the principle of analyte-induced luminescence quenching of an indicator, in particular an organic luminescent dye, fluorescent dye, or phosphorescent dye tailored to a specific analyte, which is usually incorporated into a polymer matrix. The sensor unit of such a sensor comprises, in particular, a substrate, such as a glass plate or an optical fiber, onto which the polymer / dye mixture tailored to a specific analyte is applied as a solid film. The underlying measurement principles are known from numerous publications. The applicant manufactures and markets corresponding sensors in a wide variety of configurations.

[0003] Gaseous analytes, such as oxygen, are introduced into biotechnological fermentation processes, for example in the production of biologics, using a sparger to achieve higher cell densities and thus increase product yield. Spargers are gas distributors of various geometries used to introduce gases into process environments or reaction vessels. A sparger is often located at the bottom of the reaction vessel, near the agitator, or integrated with the agitator. Sensors, on the other hand, can be installed at various locations within the reaction vessel. Common installation positions include from above through the lid or end plate of the reaction vessel, or from the side through the wall of the reactor vessel.A sensor is often inserted into the reaction vessel via a flange located on the vessel. Depending on the design, the sensor is either inserted directly into the reaction vessel or within a sensor assembly. In the case of a fermenter, for example, the sparger introduces air or oxygen bubbles into the aqueous measuring medium, which are then distributed throughout the fermenter, particularly within the measuring medium, by means of the agitator. These gas bubbles can vary in size and, as mentioned previously, adhere to the optical sensor and / or the sensor element, causing errors such as measurement spikes, erroneous readings, and / or even overloads.

[0004] The object according to the present invention is to provide a sensor spot, a sensor cap and a sensor in which the accumulation of oxygen is reduced and thus a less interference-prone signal from the sensor is achieved.

[0005] The problem is solved by the sensor spot according to the invention, a sensor cap containing a sensor spot according to the invention and a sensor that contains the cap and thus the sensor spot.

[0006] The invention relates to a method for producing a sensor spot containing a PTFE layer up to 20 µm thick in contact with the medium during operation, comprising providing a substrate, preferably a glass substrate, more preferably a glass substrate made of quartz glass,

[0007] Coating the substrate with an analyte-sensitive pigment layer arranged on the medium side, wherein the pigment layer contains at least one luminophore dye, wherein the pigment layer is configured to emit luminescence, wherein the intensity, decay time or phase shift of the luminescence depends on the concentration of the analyte in a measuring medium, preferably an aqueous one.

[0008] Coating the pigment layer with a first silicone layer arranged on the medium side,

[0009] Coating the first silicone layer with a PTFE polymer layer.

[0010] A PTFE layer in contact with the medium during operation is understood to be a layer that comprises or consists of PTFE. Preferably, at least the medium-contacting surface of the PTFE layer consists of PTFE.

[0011] In one embodiment, the coating is achieved by bonding the PTFE polymer, wherein the PTFE polymer is formed as a PTFE polymer film that is pressed onto the silicone film. In another embodiment, the PTFE polymer film is die-cut before being pressed onto the silicone film.

[0012] In one embodiment, the PTFE polymer film is etched on the surface that contacts the silicone film. This results in improved adhesion to the first silicone layer.

[0013] In one embodiment of the method, the PTFE polymer film has a layer thickness of 5-20 µm, preferably 5-10 µm.

[0014] In another embodiment of the method, the coating is applied by spray coating onto the first silicone layer. The spray coating is preferably carried out at an absolute pressure of 1-4 bar. Preferably, the thickness of the PTFE polymer layer obtained by spray coating is at least 1 µm, more preferably 1 µm to 20 µm, and even more preferably 1 µm to 10 µm.

[0015] Preferably, spray coating is carried out by applying a dispersion containing an ultrafine polymer powder comprising or consisting of PTFE polymer particles. Preferably, the dispersion is an aqueous dispersion, wherein the ultrafine polymer powder has particles with a particle diameter of 20 µm or less, preferably 0.01–20 µm, more preferably 0.1–20 µm, and even more preferably 0.1–10 µm.

[0016] In one embodiment, the coating is carried out by mixing PTFE particles with a diameter of 0.1 µm-20 µm with silicone and a solvent, preferably with alkanes, more preferably with hexane and / or heptane, and then evaporating the solvent.

[0017] The invention also relates to a sensor spot comprising a convex-shaped surface facing the medium during operation for an optical sensor for measuring an analyte in a measuring medium, comprising the layers: - a substrate facing away from the medium during operation, which is designed as a glass substrate, preferably a glass substrate made of quartz glass, - an analyte-sensitive pigment layer arranged on the medium side of the glass substrate, wherein the sensor spot contains at least one luminophore dye, wherein the intensity, decay time or phase shift of the luminescence of the analyte-sensitive pigment layer depends on the concentration of the analyte in a measuring medium, preferably an aqueous measuring medium, - a first silicone layer, a PTFE layer in contact with the medium during operation comprising a PTFE polymer, wherein the PTFE polymer preferably consists of hydrophobic or hydrophilized PTFE, wherein the PTFE layer has a thickness of 20 µm or less, preferably 15 µm or less than 15 µm, more preferably 10 µm or less than 10 µm.

[0018] The PTFE layer in contact with the medium rests on the first silicone layer on the medium side.

[0019] In one embodiment, the sensor spot comprising a PTFE layer that comes into contact with the medium during operation is obtained via a method according to the invention or an embodiment thereof.

[0020] The invention also relates to a sensor cap for an optical sensor for determining and / or monitoring at least one analyte, preferably gaseous, contained in a medium. a cylindrical inner component containing a sensor spot according to the invention or an embodiment thereof and a sleeve-shaped outer component which borders the inner component and is made of stainless steel, preferably 1.4435 stainless steel, wherein the inner component and the outer component are detachably mechanically connected to each other, preferably via a first screw connection, wherein A sealing element, preferably an O-ring, is arranged between the cylindrical inner component and the sleeve-shaped outer component on the side in contact with the medium during operation, which is designed to seal the sensor without gaps against the measuring medium.

[0021] In one embodiment, the sealing element, preferably an O-ring, is completely covered by the sleeve-shaped outer component. During operation, the sealing element is in indirect contact with the medium being measured.

[0022] The invention further relates to an optical sensor for determining or monitoring at least one analyte located in a medium, comprising a sensor cap according to the invention or an embodiment thereof, and an electronic component which are detachably connected to one another, wherein the electronic component consists of a first module comprising a light source and a detector and a second module comprising a transceiver.

[0023] In one embodiment of the optical sensor, the sensor cap is detachably connected to the electronic component via a mechanical connection, preferably via a second screw connection.

[0024] In one embodiment of the sensor according to the invention, the first and second modules are connected to each other via a detachable connector unit, wherein the detachable connector unit is designed to transmit energy and / or data via a galvanically isolated, in particular inductive, interface, wherein the detachable connector unit is preferably a bayonet fitting, wherein energy is transmitted unidirectionally from the second module to the first module, and data, in particular data on the analyte concentration, is transmitted bidirectionally between the first and the second module.

[0025] The invention further relates to an optical analysis system comprising an optical sensor according to the invention or an embodiment thereof, wherein the second module of the optical sensor is electrically connected to a data processing unit via a connection.

[0026] All embodiments of the device and method described above can be combined with each other, provided this is technically possible.

[0027] The invention is explained in more detail in the following description with reference to the embodiment shown in the drawing.

[0028] They show Fig. 1 an embodiment of the sensor spot according to the invention. Fig. 2 an embodiment of the sensor cap according to the invention. Fig. 3 an embodiment of the analysis system according to the invention.

[0029] One embodiment of the sensor spot according to the invention is in Fig. 1 shown. Fig. Figure 1 shows an embodiment of the sensor spot (2) according to the invention, comprising a PTFE polymer layer on the side facing the medium during operation. In the sensor spot (2) according to Fig. 1. The sensor layers are mounted one above the other on a substrate (3), the substrate (3), which preferably consists of quartz glass, being arranged on the side facing away from the medium during sensor operation. On the medium side of the substrate (3), the analyte-sensitive pigment layer (4) containing the luminescent dye or the luminescent dye (5) is arranged. The pigment layer (4) is configured to emit luminescence, the intensity, decay time, or phase shift of the luminescence depending on the concentration of the analyte (6) in a measuring medium (7), preferably an aqueous one. The pigment layer (4) is coated with a first silicone layer (8) arranged on the medium side. On the medium side of the first silicone layer (8), a polymer layer (1) is arranged which is permeable to the analyte to be measured but is essentially impermeable to the measuring medium (7) in which the analyte (6) is dissolved, for example, water.The PTFE polymer layer (1) is applied either by mechanical compression or by spraying an ultrafine polymer powder or a dispersion containing the ultrafine polymer powder, preferably an aqueous dispersion, onto the first silicone layer of the sensor spot (2), wherein the PTFE polymer powder has a layer thickness of 20 µm or less, preferably 15 µm or less than 15 µm, and more preferably 10 µm or less than 10 µm. The spray coating is carried out at an absolute pressure of 1–4 bar. In embodiments obtained by the method according to the invention or an embodiment thereof that includes spray coating, the layer thickness is at least 1 µm, preferably 1 µm to 20 µm, and even more preferably 1 to 10 µm.

[0030] The sensor cap (9) made of Fig. 2 includes, for example, the sensor spot (2) according to the invention coated with a PTFE polymer layer made of Fig. 1. The sensor cap (9) consists of an inner component (10), which comprises the sensor spot according to the invention or an embodiment (2) thereof, and a sleeve-like outer component (11). The inner component (10) and the outer component (11) are connected to each other via a detachable mechanical connection (12), the mechanical connection preferably being a screw connection (12).

[0031] The sensor cap (9) is also connected to the electronic component (15) of the optical sensor (14) via a second, detachable mechanical connection (21), preferably a screw connection (21). A sealing element (13), preferably an O-ring (13), is arranged between the inner component (10) and the sleeve-shaped outer component (11) at the end that contacts the medium during operation, wherein the sealing element, preferably the O-ring, is completely covered by the sleeve and is only in indirect contact with the medium (7) to be measured.

[0032] Fig. Figure 3 shows an analysis system encompassing the sensor. The sensor (14) according to Fig. 3 comprises a sensor cap (9) including a sensor spot (2) and an electronic component (15), wherein the electronic component consists of a first module (16) comprising the light source (17) and the detector (18) and a second module (19) containing the transceiver (20). The first (16) and the second module (19) are connected to each other via a mechanically detachable connector unit (22), wherein the mechanical connector unit (22) includes an inductive interface. Preferably, the mechanical connector unit (22) is a bayonet fitting. The optical sensor (14) is part of an optical analysis system (23), wherein the sensor (14) is connected to a data processing unit (25) via an electrical connection (24).

[0033] Reference punctuation marks are not to be understood as limiting the scope of the subject matter protected by the claims. They serve only to make the claims easier to understand. Reference symbol list 1 PTFE layer 2 sensor spots containing a PTFE layer 3 Substrat 4 pigment layer 5 luminescent dye 6 Analyt 7 Measuring medium / Medium 8 First silicone layer 9 Sensor cap 10 cylindrical inner components 11 a sleeve-shaped outer component, 12 detachable mechanical connection, first screw connection 13 Sealing element 14 optical sensors 15 Electronic components 16 First Module 17 Light source 18 Detector 19 Second Module 20 transceivers 21 Mechanical connection, a second screw connection between the sensor cap and the electronic component 22 Detachable plug connector unit 23 Optical Analysis System 24 Electrical connection 25 Data processing unit L Longitudinal axis of the sensor cap

Claims

Method for producing a sensor spot (2) comprising a PTFE layer (1) up to 20 µm thick and in contact with the medium during operation, comprising: providing a substrate (3), preferably a glass substrate, more preferably a glass substrate made of quartz glass; coating the substrate (3) with an analyte-sensitive pigment layer (4) arranged on the medium side, wherein the pigment layer (4) contains at least one luminophore dye (5), wherein the pigment layer (4) is configured to emit luminescence, wherein the intensity, decay time or phase shift of the luminescence depends on the concentration of the analyte (6) in a measuring medium (7), preferably an aqueous medium; coating the pigment layer (4) with a first silicone layer (8) arranged on the medium side; and coating the first silicone layer (8) with a PTFE polymer layer (1). Method according to claim 1, wherein the coating is carried out by bonding the PTFE polymer, wherein the PTFE polymer is formed as a PTFE polymer film which is pressed onto the silicone film. Method according to claim 2, wherein the PTFE polymer film has a layer thickness of 5-20 µm, preferably 5-10 µm. Method according to claim 1, wherein the coating with the PTFE polymer layer is carried out by spray coating on the first silicone layer (8). Method according to claim 4, wherein the layer thickness of the PTFE polymer layer is at least 1 µm, more preferably 1 µm to 20 µm, and even more preferably 1 µm to 10 µm. Sensor spot (2) comprising a convex-shaped surface (2) facing the medium during operation for an optical sensor (14) for measuring an analyte (6) in a measuring medium (7), comprising the layers: - a substrate (3) facing away from the medium during operation, which is designed as a glass substrate, preferably a glass substrate made of quartz glass, - an analyte-sensitive pigment layer (4) arranged on the medium side of the glass substrate, wherein the sensor spot contains at least one luminophore dye (5), wherein the intensity, decay time, or phase shift of the luminescence of the analyte-sensitive pigment layer (4) depends on the concentration of the analyte (6) in a measuring medium (7), preferably an aqueous measuring medium (7), - a first silicone layer (8), - a PTFE layer in contact with the medium during operation, comprising a PTFE polymer, wherein the PTFE polymer preferably consists of hydrophobic PTFE or hydrophilized PTFE, wherein the PTFE layer Layer thickness 20 µm or less,preferably 15 µm or less than 15 µm, further preferably 10 µm or less than 10 µm. Sensor spot (2) according to claim 6, wherein the sensor spot (2) comprising a medium-contacting PTFE layer (1) is obtained by a method according to one of claims 1-5. Sensor cap (9) for an optical sensor (14) for determining and / or monitoring at least one analyte (6) located in a medium (7), preferably gaseous, comprising a cylindrical inner component (10) comprising a sensor spot (2) according to claim 6 or 7 and a sleeve-shaped outer component (11) which borders the inner component (10) and is made of stainless steel, preferably 1.4435 stainless steel, wherein the inner component (10) and the outer component (11) are detachably mechanically connected to each other, preferably via a first screw connection (12), wherein a sealing element (13), preferably an O-ring, is arranged between the cylindrical inner component (10) and the sleeve-shaped outer component (11) on the side in contact with the medium during operation, which is designed to seal the sensor (14) without gaps against the measuring medium. Sensor cap (10) according to claim 8, wherein the sealing element (13) is completely covered by the sleeve-shaped outer component (11). Optical sensor (14) for determining or monitoring at least one analyte located in a medium, comprising a sensor cap (10) according to claim 8 or 9, and an electronic component (15) which are detachably connected to each other, wherein the electronic component (15) consists of a first module (16) comprising a light source (17) and a detector (18) and a second module (19) comprising a transceiver (20). Optical sensor (14) according to claim 10, wherein the sensor cap (10) is detachably connected to the electronic component (15) via a mechanical connection, preferably via a second screw connection (21). Optical sensor (14) according to claim 10 or 11, wherein the first (16) and the second module (19) are connected to each other via a detachable connector unit (22), wherein the detachable connector unit (22) is configured to transmit energy and / or data via a galvanically isolated, in particular inductive, interface, wherein the detachable connector unit (22) is preferably a bayonet fitting (22), wherein energy is transmitted unidirectionally from the second module (19) to the first module (16), and data, in particular data on the analyte concentration, is transmitted bidirectionally between the first (16) and the second module (19). Optical analysis system (23) comprising an optical sensor (14) according to one of claims 10 to 12, wherein the second module (19) of the optical sensor is electrically connected to a data processing unit (25) via a connection (24).

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