DE102014202595B4 - Method and device for determining oxygen in a closed container - Google Patents

Abstract

Method for determining an oxygen concentration and/or a nitrogen concentration of a gas volume (21) in a closed container (20), the container (20) having at least one transparent container area, comprising the steps of automatically supplying the container (20) by means of a transport device ( 80), and- directing a light beam (50) from a light source (40) onto the gas volume (21) in the container (20), the light beam (50) being directed through the transparent container area, characterized by- determining an oxygen concentration and/or a nitrogen concentration in the gas volume (21) by means of Raman spectroscopy, with an opaque shielding element (30) being slipped over the container (20) in order to avoid external light effects during the measurement process, and with light from the light source (40) which emits the light beam (50th ) is generated, is conducted to the shielding element (30) via a first flexible light guide (41) and the scattered light (51) of the light beam (50) is conducted from the shielding element to the Raman spectroscope (60) by means of a second flexible light guide (61).

Description

State of the art

The present invention relates to a method for determining an oxygen concentration and/or a nitrogen concentration of a gas volume in a closed container.

In the case of products in the pharmaceutical and food industries in particular, there are applications in which no or less oxygen and/or nitrogen or less than typically contained in air may be present. This can be checked, for example, using electrochemical sensors or lambda sensors, the container having to be destroyed for this purpose. However, such test methods have very long test times and do not have a linear characteristic due to a logarithmic signal concentration curve. This necessitates a complex calibration that usually has to be carried out relatively often. Also, concentrations below 1% oxygen content cannot be determined with sufficient certainty. Furthermore, the DE 10 2009 026 744 A1 a method for leak testing a container with a closed volume using Raman spectroscopy. However, the oxygen or nitrogen concentration of the gas in the container is not determined.

U.S. 5,285,071 A discloses a gas test cell device having a plurality of cells each connectable to a gas line. The cells are aligned parallel to each other. The gas test cell apparatus is configured to sequentially align the cells to an infrared light beam source, thereby passing a beam of energy through the cells. The device includes a source-aligned detector for receiving light transmitted through the cells from the source. Not closer lying prior art is in DE 10 2010 052 434 A1 , WO 99/60384 A1 , DE 694 24 382 T2 , U.S. 5,194,913A , US 2014/0118732 A1 , EP 1 226 432 B1 , US 2003/0190262 A1 , DE 27 23 939 A1 , U.S. 6,325,978 B1 , U.S. 4,784,486 A as well as U.S. 2004/0077075 A1 disclosed.

Disclosure of Invention

The method according to the invention for determining an oxygen concentration and/or nitrogen concentration with the features of claim 1 has the advantage that a sufficiently exact oxygen concentration and/or nitrogen concentration, in particular in a range of less than 1%, can be detected in a non-destructive manner. In particular, residual oxygen can be reliably determined in medical and pharmaceutical containers, e.g. vials, quickly and without contact, in situ. For this purpose, according to the invention, a container having a closed gas volume, which has at least one transparent container area or is completely transparent, e.g. made of glass, is automatically fed in by means of a transport device. After being fed in by means of the transport device, a light beam is directed onto the gas volume in the container. The light beam is directed from the outside through the transparent container area into the interior of the container and then an oxygen concentration and/or a nitrogen concentration in the gas volume is directly determined by means of Raman spectroscopy. Due to the short throughput time, it can be made possible in particular for complete product batches to be checked using the method according to the invention and not just random checks. The Raman spectroscopy enables a strictly linear method and thus in particular a simple calibration of the system. Furthermore, a non-integrating method along the optical path is made possible, so that a punctiform oxygen concentration or a punctiform nitrogen concentration can be detected. Oxygen and nitrogen can also be measured directly by means of Raman spectroscopy, so that a usable measurement result is immediately available and, for example, a defective container can be rejected immediately. The test time is preferably less than 1 second.

In order to avoid undesired light effects caused by extraneous light, according to the invention an opaque shielding element is slipped over the container. The shielding element is preferably slipped over the container to be checked. Alternatively, the shielding element can also cover several containers at the same time and the containers can be measured one after the other.

According to the invention, the light from a light source, which generates the light beam, is guided to the shielding element via a flexible light guide. More preferably, the scattered light is directed to the spectrograph via a second flexible light guide. As a result, the shielding element can be easily moved, for example in the vertical direction. The light source is preferably a laser.

The dependent claims show preferred developments of the invention. More preferably, the Raman spectroscope detects the scattered light of the light beam in an angular range of 0° to 180° and in particular at an angle of 90° to the light beam. This allows a structurally simple, very fast and accurate measurement can be made possible. In the case of a transparent container, for example, detection can also take place from above or below the container through a cover or a base.

More preferably, the container is removed after the measurement with the same transport device with which the container was fed. Furthermore, at the same time, a subsequent container is fed in for a next measuring process. The transport device can be, for example, a conveyor belt or a star wheel or a turntable or the like. A star wheel is particularly preferably used here, since it does not have to be stopped during the measurement process. A size (diameter) of the star wheel is designed in such a way that so many test specimens are arranged on the star wheel that the rotational speed is adapted to the test duration and the number of tests per time (cycle rate).

In order to be able to carry out cycle times that are as short as possible, the measurement process is preferably carried out in a time window of 0.5 seconds to 1 second.

More preferably, the containers to be measured are supplied in an upright position, so that the gas volume to be measured is always located in the upper area of the container.

Furthermore, the present invention relates to a device for determining an oxygen concentration and/or nitrogen concentration of a gas volume in a closed container. The device comprises a transport device for automatically feeding in the containers, a light source, in particular a laser, for emitting a light beam into the gas volume and a Raman spectroscope for detecting scattered light from the light beam in order to determine the desired gas concentration. The device is preferably designed as a complete assembly and can in particular be attached to or integrated into filling and packaging machines or the like.

According to the invention, the device also comprises an opaque shielding element which shields the closed container from extraneous light. The shielding element is particularly preferably slipped over the container to be tested. Alternatively, the test specimens are driven into a tunnel, the entrance and exit of which is darkened with a light protection curtain, and driven out again after the test has been completed. In this case, several test specimens are preferably arranged in front of and behind the test point in the tunnel in order to have a sufficient distance to the light protection curtains at the entrance and exit of the tunnel.

According to the invention, the device further comprises a first flexible light guide, which connects the light source to the shielding element and directs the light beam into the interior of the shielding element, and a second flexible light guide, which connects the shielding element to the Raman spectroscope and transmits scattered light of the light beam to the Raman spectroscope conducts.

For a quick and accurate measurement, the Raman spectroscope is preferably arranged at an angle of 0° to 180° and in particular at an angle of approximately 90° to the light beam, or alternatively above or below the container.

More preferably, the transport device is a conveyor belt or a star wheel or a turntable or the like. As a result, the containers to be checked can simply be fed in and removed in cycles. The cycle time is preferably in a range from 0.5 seconds to 1 second.

Furthermore, the present invention relates to a filling and/or sealing machine for pharmaceutical containers or food containers, comprising a device according to the invention. Furthermore, the device according to the invention and the method according to the invention can also be used in quality assurance, for example for determining the residual oxygen in coating processes, e.g. in the solar industry.

According to the invention, a gas concentration in a closed container or area can thus be determined quickly and reliably using an optical, non-destructive method. The invention also enables complete batches to be checked, which is particularly advantageous for pharmaceutical products that must not come into contact with oxygen.

character list

• 1 eine schematische Draufsicht auf eine erfindungsgemäße Vorrichtung gemäß einem ersten bevorzugten Ausführungsbeispiel der Erfindung,
• 2 eine schematische Seitenansicht der Vorrichtung von 1 und
• 3 eine schematische Schnittansicht einer erfindungsgemäßen Vorrichtung gemäß einem zweiten Ausführungsbeispiel der Erfindung.

Preferred embodiments of the invention are described in detail below with reference to the accompanying drawings. The same reference symbols have been used in the drawing to denote the same components. In the drawing is:

• 1 a schematic plan view of a device according to the invention according to a first preferred embodiment of the invention,
• 2 a schematic side view of the device of FIG 1 and
• 3 a schematic sectional view of a device according to the invention according to a second embodiment of the invention.

Preferred Embodiments of the Invention

In 1 is a schematic top view of a device 10 according to the invention for determining an oxygen concentration of a gas volume 21 of a closed container 20 according to a first embodiment of the invention.

The container 20 has an inner closed volume which is filled with a powdery or liquid or solid or gaseous substance 22 and the closed gas volume 21 . How out 2 As can be seen, the container 20 is arranged upright so that the volume of gas is in the upper part of the container. The container 20 is closed by means of a cover 23 .

The device also includes a transport device 80, which is a conveyor belt in this exemplary embodiment. In a previous step, the sealed containers 20 were filled with the powdered substance 22, e.g. a drug, and then an inert gas was brought into the container 20 as an internal sealed gas volume in order to keep the oxygen concentration in the container as low as possible. The container was then sealed.

The device 10 also includes a light source 40, which is a laser in this exemplary embodiment. The laser emits a laser beam 50, which, as in 2 shown, is directed through the gas volume 21 located in the container 20 . The laser beam 50 is absorbed by means of an absorber 70 positioned on the side of the container 20 opposite the laser.

The device also includes a Raman spectrograph 60 for detecting and evaluating scattered light 51 of the laser beam 50. As shown in FIG 2 As can be seen, the scattered light is guided to the spectrograph 60 for concentration measurement at an angle θ, which is 90° in this exemplary embodiment. The angle θ, which is also referred to as the detection angle, can assume values between 0° and 360° and in particular between 90° and 180°.

The closed container is preferably completely transparent, and in particular made of glass. Alternatively, the closed container can also be a flexible container, for example food packaging, which has at least one transparent container area through which the laser beam 50 can reach the interior of the container and via which the scattered light can reach the Raman spectrograph 60 .

The transport device 80 is as shown 1 can be seen, used both for feeding and for removing containers to the measuring device. Reference numeral 20a designates a container on which the gas concentration measurement has already been performed, and reference numeral 20b designates a container which is measured after the container 20 just measured.

The spectrograph 60 preferably includes a monochromator (not shown separately) for selecting scattered light incident on the spectrograph 60 having a wavelength corresponding to the Raman spectral band to be detected, i.e., oxygen or nitrogen. More preferably, the spectrograph 60 includes a CCD camera (not shown separately) for converting the scattered light selected by means of the monochromator into a measurement voltage. The measurement voltage generated by the CCD camera is directly proportional to the number of photons that have been scattered by the gas to be measured at the detection angle θ Raman and have hit the spectrograph within a specified detection time.

3 shows a device 10 according to a second embodiment of the invention. The device also includes an opaque shielding element 30 which is slipped over the closed container 20 to be measured. The inside of the shielding element 30 is connected to the light source 40 via a first flexible light guide 41 . Furthermore, a second flexible light guide 61 is provided, which connects the shielding element 30 to the Raman spectrograph 60 . The shielding element 30 can be placed on the transport device 80 and is used to avoid disturbing influences from extraneous light, which could adversely affect the measurement. The shielding element 30 can be placed in the direction of the double arrow B on and off the transport device 80, which in this exemplary embodiment is also a conveyor belt in the vertical direction. The mobility of the shielding element 30 is maintained through the use of the two flexible light guides 41, 61.

Claims (9)

Method for determining an oxygen concentration and/or a nitrogen concentration of a gas volume (21) in a closed container (20), the container (20) having at least one transparent container area, comprising the steps of - automatically feeding in the container (20) by means of a transport device (80), and - aligning a light beam (50 ) a light source (40) onto the gas volume (21) in the container (20), the light beam (50) being directed through the transparent container area, characterized by - determining an oxygen concentration and/or a nitrogen concentration in the gas volume (21) by means of Raman Spectroscopy, wherein an opaque shielding element (30) is slipped over the container (20) in order to avoid external light effects during the measurement process, and wherein light from the light source (40), which generates the light beam (50), passes to the shielding element (30). a first flexible light guide (41) and the scattered light (51) of the light beam (50) is guided by means of a second flexible light guide (61) from the shielding element to the Raman spectroscope (60). Method according to one of the preceding claims, characterized in that the light beam (50) is a laser beam. Method according to one of the preceding claims, characterized in that the Raman spectroscope (60) detects the scattered light (51) of the light beam (50) in an angular range between 0° and 180° and in particular in an angle of approximately 90°. Method according to one of the preceding claims, characterized in that the container (20) is transported away by means of the transport device (80) after the measuring process and that at the same time a subsequent container (20b) is supplied for a next measuring process. Method according to one of the preceding claims, characterized in that the measurement process is carried out in a time window of between 0.5 seconds and 1 second. Device for determining an oxygen concentration and/or a nitrogen concentration in a gas volume (21) of a closed container (20), comprising - a transport device (80) for automatically feeding in the container (20), the container (20) having at least one transparent container area , and - a light source (40) for emitting a light beam (50) which penetrates the gas volume (21) and which can penetrate through the transparent container area into the gas volume (21), characterized by - a Raman spectroscope (60) for detecting scattered light (51) of the light beam (50) to determine the oxygen concentration and/or the nitrogen concentration, - an opaque shielding element (30) which can be slipped over the closed container (20), - a first flexible light guide (41) which connects the light source to the shielding element (30) and directs the light beam (50) into the interior of the shielding element (30), and - a second flexible light guide (61) which connects the shielding element (30) to the Raman spectroscope (60) and stray light (51) of the light beam (50) to the Raman spectroscope (60). device after claim 6 , characterized in that the scattered light (51) can be detected in an angular range of 0° to 180° and in particular in an angle (θ) of approximately 90° to the light beam (50). Device according to one of Claims 6 or 7 , characterized in that the transport device (80) is a conveyor belt or a star wheel or a rotary table and/or that the transport device (80) has a cycle time of less than 1 s. Filling and/or sealing machine for pharmaceutical containers or food containers, comprising a device according to one of Claims 6 until 8th .

Images