DE102011120845A1 - Device for contactless determination of e.g. oxygen content in multi-pane system during production of e.g. vacuum insulation panel, has luminescent substances provided in gas-filled or low pressurized component or composite element - Google Patents

Abstract

The device has a detector (10) for measuring fluorescence. Independent, structurally separated luminescent substances are provided in a gas-filled or low pressurized component of a gas filled multi-pane glazing or a partial translucent gas-filled or low pressurized composite element. The substances are excited by light of specific wavelength for emission of radiation, where luminescence of the substances is reduced by gas that is introduced in an intermediate space (5) between panes (3). A mobile measurement unit is connected with a light source (11) e.g. laser and LED, and the detector.

Description

The invention relates to a device for determining the gas content, in particular oxygen or noble gas content, in gas-filled or vacuum-operated multi-plate systems. To determine the gas content, for example the oxygen content, a dye which is integrated in the space between the panes is irradiated with light, whereby it is excited to fluoresce. According to the oxygen concentration in the space between the panes, the fluorescence in the dye is quenched. Based on the cooldown and the intensity of the deleted fluorescence, the oxygen content can be detected. Since the quenching process is specific to a particular gas-dye combination, the gas composition and, with known gas composition, the pressure of the atmosphere in the composite element can be determined.

[State of the art]

In the European patent specification EP 0 083 703 B1 describes a medical measuring device which measures the oxygen content in biological systems by means of fluorescence quenching. When determining the oxygen content in biological systems, fast response times of less than 10 ms and no dead time are required. To ensure this, very thin layers of the luminescent material are needed. For this purpose, a layer structure of single-layer densely packed particles is used here.

The patent DE 39 00 191 C2 extends the previous patent specification EP 0 083 703 B1 to an isolation of the excitation and measurement signal from disturbing ambient light. The measuring device is optically decoupled from the sample medium by a blackened, vulcanized layer in order to ensure a sufficiently high fluorescence quenching signal strength, despite the small amount of dye. In the European patent specification EP 1 001 128 B1 describes a method for checking the state of the gas filling in insulating glass panes, in which an unspecified sensor means reacts when a limit value is exceeded with a signal output.

In the patent DE 34 209 47 C2 At the same time, different substances with arbitrary fluorescence indicators and different substance concentrations are determined with the help of fluorescence indicators, which no longer necessarily have to be specific for the substances to be investigated. For this purpose, the diminished or deleted fluorescence intensities are measured and compared with the known undeleted intensities.

In the patent application WO 002002056023 A1 ( DE 101 01 576 A1 ) are the different times of the luminescence response of an indicator material and a reference material for determining the concentration of various substances, such as. As oxygen, carbon dioxide, sodium, or other parameters such. B. compared to the pH in, for example, blood.

In the production of noble gas-filled multi-pane glazings or the production of vacuum insulating glass, sufficient filling with inert gas or ensuring the necessary underpressure is a critical process step. The level of noble gas is only checked randomly by the insulating glass manufacturers, if at all. To this end, some meters are available on the market, which allow under certain circumstances, a control of the degree of gas filling in the space between the panes from the outside (eg, gasglass Sparkly). However, these meters are only very limited applicability because z. B. layers with low emissivity, so-called low-e-layers, not allowed to be between the meter and gas volume to be tested. In the increasingly used triple insulating glasses, the coatings are usually mounted on the inner sides of the outer panes, thereby a reliable quality control of Gasfüllgrades in this arrangement is not possible with these devices. Some insulation glass manufacturers therefore check the degree of gas filling by means of gas extraction from the space between the panes. However, this is very expensive and takes place only randomly. A satisfactory option for inline quality control of every manufactured glazing is not yet available.

The requirements of such a measuring device are short measurement times, which meet the cycle times in the production of insulating glass of less than 60 seconds, as well as a sufficiently accurate detection of Gasfüllgrades in the space between the panes. Furthermore, the degree of gas filling, in addition to the emissivity of the coating, one of the main factors influencing the heat transfer value (U _g value) of a glazing. However, the emissivity of disc surfaces can be set and reported very reliably by the manufacturers so that accurate determination of the degree of gas filling in the manufacture of insulating glass would also ensure quality control of the U _g value.

In the case of composite elements that operate under reduced pressure to reduce the system's gas thermal conductivity (eg vacuum insulation panels, certain airgel glazings), there is also the problem of determining the gas pressure in the interior from the outside. Here, with the method according to the invention, the proportion of the measurement gas in the composite element and thus, in the case of a known gas composition, the gas pressure can be determined. With opaque Systems are required for the necessary wavelengths permeable area (eg viewing window) at the desired measuring point. These elements can be quality controlled with the invention described herein.

This fast and reliable method for determining the gas filling in the interpane space is described below using the example of measuring the oxygen content by means of fluorescence quenching.

From the measured oxygen content X _O2 , the gas filling degree X _{noble gas} can be determined directly according to the following equation: X _{rare gas} = (1 - X _O2 / R _O2 ) where R _{O2 is} the oxygen content of the surrounding atmosphere.

In the following, fluorescence and luminescence are used synonymously. Fluorescence is a form of luminescence. Fluorescence is the transient, spontaneous emission of light during the transition of an electronically excited system into a state of lower energy, whereby the emitted light is as a rule less energy-consuming than that previously absorbed. In contrast to phosphorescence, fluorescence transitions are spin-allowed, i. H. they obey the selection rule ΔS = 0, that is, between states of the same spin. Fluorescence is characterized in that it ends rapidly (usually within one millionth of a second) after the end of the irradiation. Typical fluorophores, that is, physical systems in which fluorescence occurs, are atoms, molecules, ions, and semiconductor nanoparticles.

To measure the dynamic luminescence quenching, a suitable dye is irradiated with light of appropriate wavelength and the luminescence response is recorded with a detector. A suitable measuring structure is described, for example, in exemplary embodiments 9 and 10.

A luminescent substance is excited by emission of light of suitable wavelength. The luminescent substance is, for example, metal-organic complexes, in particular transition metal complexes of Ru (II), Os (II) and Rh (II) or phosphorescent, Pt (II) or Pd (II) containing porphyrins, or organic fluorescent dyes, in particular polycyclic aromatic hydrocarbons, and mixtures thereof. By colliding with molecules, in this case oxygen molecules, the energy transfer of the excited dye molecules to the oxygen molecules, which causes excited molecules to emit without emitting photons, returns to their ground state and the total emission is reduced, ie. H. the luminescence deleted. This process is called dynamic fluorescence quenching (luminescence quenching).

mit Ia der Lumineszenzintensität bei Abwesenheit von Sauerstoff, I der Lumineszenzintensität in Anwesenheit des Löschers, also Sauerstoff, [O₂] dem Sauerstoffgehalt und K_SV der Stern-Volmer-Konstante. Eine wichtige Voraussetzung für die Gültigkeit der Stern-Volmer-Gleichung ist die gleiche Erreichbarkeit aller lumineszierenden Moleküle durch den löschenden Sauerstoff. Daher ist für eine erfindungsgemäße Anwendung eine Verwendung des lumineszierenden Farbstoffes in dünnen Schichten oder in hochporösen Materialien bzw. auf den inneren Oberflächen dieser unabdingbar, um so eine gleiche Erreichbarkeit aller Moleküle sicher zu stellen.The dependence of the luminescence intensity of the luminescent dye on the oxygen concentration (the substance concentration of the extinguisher, here oxygen) is described by the Stern-Volmer equation:

with Ia the luminescence intensity in the absence of oxygen, I the luminescence intensity in the presence of the quencher, ie oxygen, [O ₂ ] the oxygen content and K _{SV of} the Stern-Volmer constant. An important prerequisite for the validity of the Stern-Volmer equation is the equal accessibility of all luminescent molecules by the quenching oxygen. Therefore, for an application according to the invention, use of the luminescent dye in thin layers or in highly porous materials or on the inner surfaces thereof is essential in order to ensure equal accessibility of all molecules.

In this case, the following relationship is established for the star volmer constant K _SV with the lifetime of the excited state of the luminescent dye τ ₀ and the lifetime τ given a corresponding oxygen concentration:

For dynamic luminescence quenching, the decrease in the lifetime τ of the excited state in the presence of the quencher (here oxygen) is characteristic. The more durable the excited state is, the more likely it is to collide between the quencher (oxygen) and the excited molecules of the dye, and thus also its quenching. For dynamic luminescence quenching, therefore, the following relationship applies:

For the same concentration of the extinguisher (oxygen), the value for K _{SV increases} in principle with increasing luminescence in the case of dynamic luminescence quenching, ie the extinguisher extinguishes more intensely at a higher temperature than at a lower temperature. The rate of diffusion of the quencher increases with increasing temperature, whereby the number of collisions with the excited molecules, and thus the number of erasures, also increases.

Furthermore, this process is indirectly dependent on the humidity, since the oxygen concentration of a gas mixture depends on the sum of the concentrations of all participating gases and thus also on the water vapor concentration. For the field of application according to the invention, this dependence can be neglected, as it is in systems filled with gas or evacuated to systems with a humidity significantly less than 0.05% RH (dew point at -60 ° C = 1.08 Pa).

OBJECT OF THE INVENTION

The invention is based on the object in the production of gas-filled or working with negative pressure multi-pane glazing or composite elements to enable a rapid measurement method of high accuracy for determining the gas mixture or gas pressure in the interior of the pane.

With the method according to the invention can be within the cycle times of 60 seconds in the production of gas-filled glazings with an accuracy of ± 1% determine the gas mixture in the space between the panes.

In principle, a number of factors must be taken into account for a correspondingly high measuring accuracy. Since, as described above, the intensity of the erasure is temperature-dependent, the temperature must be recorded as well. In the measurement according to the invention in the manufacturing process, this is largely unproblematic, since well-defined temperatures prevail in the production hall and there is no temperature difference between the outside and inside of the glazing, thus no temperature gradients can be established in the pane interior and the temperature at the measuring point can be easily detected. Furthermore, the device according to the invention takes into account the low-e coatings of the discs and the consequent corrections of the measured fluorescence intensity, which can be reduced by the disc coatings at a corresponding fluorescence wavelength.

The invention also takes into account the changes in the measured fluorescence intensity due to reflection and absorption at the layers located between the dye and the detector (eg glass panes in the insulating glass). These are dependent on the angle of incidence and must be corrected accordingly.

On the other hand, a corresponding embodiment of the measuring head ensures a well-defined measuring position with a known distance and angle between the measuring surface and the detector.

In order to ensure a better optical coupling of the detector to the disk, it is advisable to apply a liquid with a suitable refractive index, for example an immersion oil customary in microscopy, between the disk and the detector. Another possibility of adjusting the refractive index consists in the application of a thin, porous SiO ₂ -Aerogelschicht with adjusted density gradient between the detector and the disc. This has the advantage that in parts-evacuated glazings the residual gas atmosphere is not burdened by the residual gas pressure occurring in liquids.

[Embodiment 1]

• i. Ein Feld besteht aus einem schnell reagierenden, aber eventuell dafür kurzlebigen Farbstoff, um eine Qualitätskontrolle während der Inline-Produktion sicher zustellen. Das andere Feld besteht aus einem langlebigen, aber eventuell langsamer reagierenden Farbstoff, um eine Qualitätskontrolle nach Jahren zu gewährleisten.
• ii. Im Scheibenzwischenraum befinden sich mehrere Farbstofffelder an unterschiedlichen Orten, um eine Bestimmung des durchschnittlichen Gasgemisches zu ermöglichen. Auch ein Farbstoffstreifen über die gesamte Scheibenhöhe oder mindestens einen Teil von dieser ist eine sinnvolle Ausführungsform.
• iii. Es befinden sich mehrere Felder im Scheibenzwischenraum mit verschiedenen Farbstoffen, die auf unterschiedliche Gase reagieren. So ist beispielsweise ein Feld mit einem Farbstoff, dessen Lumineszenz durch Argon gelöscht wird, besetzt und ein weiteres Feld mit einem Farbstoff, dessen Lumineszenz durch Sauerstoff gelöscht wird.
• iv. Es befinden sich mehrere Felder im Scheibenzwischenraum mit verschiedenen Farbstoffen, die in unterschiedlichen Konzentrationsbereichen eine entsprechend hohe Auflösung ermöglichen. Beispielsweise wird für eine Bestimmung des Sauerstoffgehaltes unterhalb von 5% ein Feld mit einem Pt(II) oder Pd(II) enthaltenden Porphyrin besetzt und ein weiteres Feld wird mit einem metall-organischen Komplex, insbesondere einem Übergangsmetallkomplex von Ru(II) für die Bestimmung höherer Sauerstoffkonzentrationen belegt.

This embodiment sees at least two different dye fields 1 in the space between the panes 5 before, see ,

• i. A field consists of a fast-reacting but possibly short-lived dye to ensure quality control during inline production. The other field consists of a durable, but possibly slower, dye to ensure years of quality control.
• ii. In the space between the panes there are several color fields at different locations to enable a determination of the average gas mixture. A dye strip over the entire slice height or at least a part of this is a useful embodiment.
• iii. There are several fields in the space between the panes with different dyes that react to different gases. For example, one field is occupied by a dye whose luminescence is quenched by argon and another field is occupied by a dye whose luminescence is quenched by oxygen.
• iv. There are several fields in the space between the panes with different dyes, which enable a correspondingly high resolution in different concentration ranges. For example, for a determination of the oxygen content below 5%, one field is occupied by a porphyrin containing Pt (II) or Pd (II) and another field is occupied with a metal-organic complex, in particular a transition metal complex of Ru (II) for the determination occupied higher oxygen concentrations.

[Embodiment 2]

For spatially resolving measurements is a dye coated ball 8th introduced in the space between the panes.

• i. The ball is magnetic and can be activated by a magnet 9 be moved from the outside through the disc in the entire space between the panes or at least in a partial area. Furthermore, both the detector for measuring the fluorescence intensity 10 and the stimulating light source 11 be integrated in the magnet or a combined measuring head 12 result.
• ii. The ball is moved mechanically, pneumatically, hydraulically or electrically along a rail or open tube through the different pulley heights.

Furthermore, with a short-lived dye, a light-tight sealable box 7 be integrated into the edge bond or the disc space to extend the life of the dye, see ,

[Embodiment 3]

Here, the dye is applied to a transponder (electronic component for storage and non-contact reading of data), which is in the space between the panes 5 is arranged. The transponder stores all relevant data of the glazing (structure, characteristic values, manufacturer, date, etc.). About the dye 1 In addition, the degree of gas filling can be determined. Thus, all important parameters of the glazing can be retrieved from the outside, even when installed.

[Embodiment 4]

For three-pane insulating glazings (cf. ) become at least two dye fields 1 needed. There are two separate spaces between the panes 5 present, the dye must be introduced into each individual chamber. The measurement is carried out through the usually coated outer pane. Low-e layers reduce the intensity of the measurement signal, which should be taken into account in the evaluation and, for example, if the signal strength is too low, due to focusing (cf. ) can be compensated for the dye field. The detection of the measurement signal can be done from both sides (see ) as well as from one side. In the latter case, a dye field is detected through two slices, here too attention must be paid to a sufficient signal strength and corresponding correction factors due to multiple reflection and varying refractive indices must be included. When measured through a disk, these correction factors may also become relevant when the dye field is z. B. on the spacer 4 is or is not sufficiently coupled to the outer pane.

[Embodiment 5]

A device for determining the degree of gas filling in the manufacture of insulating glass (inline quality control) or the production of composite elements comprises at least one measuring head 12 and at least one dye field 1 (see. ). The measuring head in each case comprises an excitation unit 11 for irradiation of the dye field with light of appropriate wavelength for the excitation of the fluorescence of the dye used, as well as a detection unit 10 for the quantitative determination of the emitted fluorescent light (cf. ). With an additional look 13 consisting of at least two converging lenses, the excitation and the measurement signal can be amplified if necessary (see. ). The dye field is before the assembly of the insulating glass on the inside of the disc or on the spacer 4 appropriate. Subsequently, the individual parts drive with dye field into the gas filling plant. There the noble gas is filled in and the individual parts are joined together to form the insulating glass. After leaving the gas filling plant, the dye field - now inside the gas-filled chambers - passes the measuring head. The excitation unit irradiates the dye field from the outside, the detection unit detects the intensity of the emitted radiation and thus determines the degree of gas filling. For double-pane insulating glass, one measuring head is sufficient. The three-disc insulating glass uses either two probes that simultaneously detect the degree of gas filling on both sides, or uses a measuring head that either measures from either side in succession or measures the second chamber through two disks. Alternatively, the measuring head can already be locked in the gas filling system at the suitable measuring position before it is filled. The advantage here is that the degree of gas filling of the element to be filled can be detected before and after filling. In this way it is possible to determine the degree of filling on the basis of the difference between the two measured values, at the same time eliminating disturbing factors caused, for example, by temperature deviations or intensity-reducing coatings.

It is also possible to equip a measuring head with several excitation and detection units. This can be used on the one hand for the simultaneous measurement of both chambers in three-pane glazing from one side. On the other hand, an embodiment for different dyes and thus for different design ranges of the excitation and detection unit is possible. Hereby, the exact gas mixture can be determined in only one measurement, for example if three different dyes whose fluorescence is quenched by three different gases (eg oxygen, nitrogen, argon) are used.

LIST OF REFERENCE NUMBERS

1

Dye / measurement field

3

disc

4

spacer

5

gas-filled or evacuated space

6

Polarizing filter or switchable coating

7

Light Fender

8th

Dye coated ball

9

magnet

10

Detector for measuring fluorescence intensity

11

Light source, stimulating wavelength

12

Measuring head attachment with well-defined geometry to the measuring field

13

optics

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

• EP 0083703 B1 [0002, 0003]
• DE 3900191 C2 [0003]
• EP 1001128 B1 [0003]
• DE 3420947 C2 [0004]
• WO 002002056023 A1 [0005]
• DE 10101576 A1 [0005]

Claims (13)

Device for non-contact determination of the gas content in hermetically sealed systems, in particular in gas-filled or vacuum-operated multi-plate systems or composite elements, characterized in that the device consists of at least i. a light source of a particular wavelength, in particular a laser or an LED, ii. a detector for measuring fluorescence iii. and one of two independent, structurally separate luminescent substance in a gas-filled or vacuum-operated component, in particular a gas-filled multi-pane glazing or an at least partially translucent, gas-filled or working with negative pressure composite element. Apparatus according to claim 1, characterized in that i. at least one luminescent substance whose luminescence is reduced by a corresponding gas, in particular oxygen, nitrogen or a noble gas (fluorescence quenching), is introduced in the space between the panes, ii. this substance is excited by light of a certain wavelength to emit radiation, iii. the intensity of the emitted radiation is measured, iv. the measuring time for determining the gas content is less than 60 seconds, in particular less than 30 seconds, in particular less than 10 seconds, v. the accuracy of measurement with respect to the oxygen content in gas-filled discs with less than 10% air at 0.6%, in particular at 0.2%, or in composite elements or multi-disc systems with negative pressure measurement accuracy with respect to the oxygen content is at least 1%. Device according to one of claims 1 or 2, characterized in that the luminescent substance is applied directly to one of the glass panes, the edge seal or the sealing material of a multi-pane glazing. Device according to one of claims 1 or 2, characterized in that the luminescent substance is applied to a flat substrate, which is fixed in the space between the panes, in particular on the glass or the spacer, or is movable in the space between the panes. Device according to one of claims 1 or 2, characterized in that the luminescent substance on eifern transponder is partially or completely applied and this is fixed in the space between the panes, in particular on the glass or the spacer. Device according to one of claims 1 or 2, characterized in that the luminescent substance on a three-dimensional body, in particular a ball, is applied, which is located in the space between the panes, in particular there is movable. Device according to one of claims 1 to 6, characterized in that the substance in parts of the space between the panes or the entire space between panes for a location-dependent measurement mechanically, for example by an electric, pneumatic or hydraulic device, can be moved. Device according to one of claims 1 to 6, characterized in that the substance in parts of the space between the panes or the entire space between panes can be moved magnetically for a location-dependent measurement, in particular by a magnetic carrier material or a magnetic body. Device according to one of claims 1 to 8, characterized in that the intensity of the emitted light is normalized in the measurement by mechanical or optical controller or by varying the intensity of the exciting light in different disc systems to an equal value or by a reference substance outside the disc system. Device according to one of claims 1 to 9, characterized in that the luminescent substance acts as a getter in working with vacuum disc systems or composite elements. Device according to one of claims 1 to 100, characterized in that a substance, preferably a liquid or a gel, with a refractive index close to that of glass, preferably between 1.3 and 1.6, improves the coupling between the disk and the measuring head. Device according to one of claims 1 to 11, characterized in that a mobile measuring unit is connected by an optical system, in particular an optical fiber, with the light source and the detector. Device according to one of claims 1 to 12, characterized in that the measuring unit contains at least one transponder reading unit, in particular additionally a transponder writing unit.

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