Analyzer with chemical filter surrounding measurement chamber

Abstract

The invention relates to an analyzer having a measurement chamber (30) and a sensor (10, 11). A measurement chamber (30) receives a gas sample (Gp). The sensor (10, 11) generates a signal relating to a target gas concentration in the gas sample (Gp). The filter component (20) with the chemical filter (22) and the further component (21) enclose the measurement chamber (30) and together form a dimensionally stable component. In addition to the respective at least one opening # imgabs0 #, both the filter member (20) and the further member (21) are impermeable to gas. The gas sample (Gp) is forced to flow through a gap (Sp.i) between the filter member (20) and the further member (21) on a path from the outside into the measurement chamber (30). The chemical filter (22) binds a substance present or possibly present in the gas sample (Gp), or decomposes the substance before the gas sample (Gp) reaches the measurement chamber (30).

Description

Technical Field

[0001] The invention relates to an analyzer having a measuring chamber, a sensor located at or in the measuring chamber, and a chemical filter surrounding the measuring chamber. Background Art

[0002] An analyzer is capable of measuring the concentration of at least one target gas in a gas sample and generating a signal related to the measured target gas concentration—in other words, including information about the measured target gas concentration. Different sensor principles for such analyzers are known. One principle exploits the fact that the target gas absorbs electromagnetic radiation in a certain wavelength range. This electromagnetic radiation penetrates the gas sample to be examined. A detector measures the intensity of the impinging electromagnetic radiation. Another principle exploits the fact that a combustible target gas releases heat when heated and oxidized. This released heat is a measure for the target gas concentration. The present invention can be used in conjunction with sensors designed in this manner. Summary of the Invention

[0003] The present invention is based on the object of providing an analyzer which is capable of measuring the concentration of a predetermined target gas in a gas sample and which has a lower cross-sensitivity to substances present or possibly present in the gas sample than known analyzers.

[0004] This object is achieved by an analysis device according to the invention. Advantageous embodiments of the analysis device according to the invention are specified in the remaining embodiments according to the invention.

[0005] The analyzer according to the present invention comprises a measuring chamber and a sensor. The measuring chamber is capable of receiving a gas sample. The gas sample originates from the spatial region to be monitored and flows from there into the measuring chamber. The sensor is capable of measuring the concentration of a target gas in the gas sample and generating a signal. The generated signal is correlated with the measured concentration of the target gas in the gas sample and therefore includes information about the measured target gas concentration, wherein the gas sample is located in the measuring chamber. The sensor can be designed to measure the respective concentrations of multiple target gases or the sum of the concentrations of multiple target gases. Preferably, the sensor is arranged in and / or at the measuring chamber.

[0006] Note: The expression "a sensor is capable of measuring a physical variable" means that the sensor measures a direct physical variable or at least one other variable that is related to the desired physical variable and is therefore a measure of the desired physical variable. The measurement provides at least one value for the physical variable. In this case, the sensor measures a detection variable, in particular a voltage, charge, or other electrical detection variable, that is related to the desired target gas concentration.

[0007] The analyzer further comprises a filter component with a chemical filter and another component. The filter component and the other component jointly surround the measuring chamber, or more precisely, completely surround it. It is feasible that the filter component and the other component each only surround a portion of the measuring chamber. On the other hand, preferably, the filter component completely surrounds the measuring chamber, and the other component also completely surrounds the measuring chamber.

[0008] The filter element and the other element are both inherently shape-stable. It is feasible that the filter element and the other element are both inherently shape-stable. It is also feasible that the filter element retains the form of the other element, or conversely, the other element retains the form of the filter element. Preferably, the filter element and the other element are fixed to the housing surrounding the measuring chamber so that, during use, neither the filter element nor the other element can move relative to the housing surrounding the measuring chamber.

[0009] NOTE: A dimensionally stable component is understood to be a component that retains its shape during use or at least re-assumes its original shape when compressed, stretched or deformed in another way. A dimensionally stable component can therefore be, in particular, elastically deformable or rigid. Components made of metal or rigid plastic are dimensionally stable; sheets or fabrics are not.

[0010] At least one filter opening is embedded in the filter component. At least one component opening is embedded in the other component. Except for the corresponding at least one opening, not only the filter component but also the other component is impermeable to gas. Therefore, the gas sample from the spatial area to be monitored only reaches the inside of the measuring chamber on the path through the or at least one component opening and through the or at least one filter opening. "Impermeable" means: the two components are ideally completely impermeable to gas, so that the gas sample can only reach the measuring chamber through one or more component openings and one or more filter openings. In practice, the two components are only impermeable except for the opening and inevitable slits, gaps and / or other inevitable recesses. Usually, due to material inaccuracies and deformations caused by ambient temperature, it is inevitable that a small part of the gas sample reaches the inside of the measuring chamber through the or each opening. But generally speaking, this will not cause distortion of the measurement result.

[0011] The chemical filter is an integral part of the filter element. It is possible that the entire filter element is used as a chemical filter.

[0012] A gap is created between the filter element and the other element, preferably a surrounding gap. The or each filter opening and the or at least one element opening are arranged as follows: a gas sample flowing into the interior of the measuring chamber from the outside (i.e., from the spatial region) is forced onto a path through the gap or a portion of the gap and passes through the chemical filter on the path through the gap. The gas sample thus flows through the chemical filter before reaching the measuring chamber. Any relevant portion of the gas sample cannot bypass the chemical filter and then reach the measuring chamber.

[0013] Before the gas sample reaches the interior of the measurement chamber, the path along which the gas sample is forced includes a path section. This path section is located in the gap and has a length of at least 0.5 cm, preferably at least 1 cm or 2 cm, particularly preferably at least 5 cm, and especially at least 10 cm. Before the gas sample reaches the measurement chamber, the gas sample flows through the chemical filter at least along this path section.

[0014] The chemical filter can achieve the following effect: the chemical filter binds a chemical substance that is or at least may be present in the gas sample, or breaks up the chemical substance, or converts the chemical substance. For example, it can chemically convert gaseous substances in the gas sample into solid substances. The chemical filter can achieve this effect when the gas sample flows through the gap and passes through the chemical filter. Ideally, the filter component with the chemical filter and the other component prevent the relevant amount of chemical substances that are part of the gas sample from reaching the interior of the measurement chamber through the interaction just described.

[0015] According to the present invention, the or at least one predetermined chemical substance is prevented from entering the interior of the measuring chamber. "Predetermined" means that the substance is present in the spatial region to be monitored and, therefore, also in the gas sample, or at least potentially present there. The substance is known. It is generally undesirable for at least one predetermined substance to enter the interior of the measuring chamber as part of the gas sample. For example, the substance could damage or render inoperable components within the measuring chamber. It is also possible that the substance could distort, or at least potentially distort, the analyzer's measurement results.

[0016] It is conceivable to arrange a filter around the measuring chamber, wherein the filter is designed as a flow-through filter. The gas sample flows through holes in the flow-through filter into the interior of the measuring chamber, and the flow-through filter removes substances from the flowing gas sample or otherwise prevents substances from reaching the interior of the measuring chamber.

[0017] Conceivable designs with flow-through filters have the following disadvantages: Flow-through filters generally have a higher aerodynamic flow resistance than chemical filters in the filter element and other components of the analyzer according to the present invention. Consequently, it typically takes longer for the gas sample to flow through the flow-through filter and reach the interior of the measuring chamber. Consequently, an analyzer with a flow-through filter can only detect the target gas or gases after a longer time than an analyzer according to the present invention.

[0018] A shorter response time compared to a flow-through filter is achieved in particular by the fact that the gas sample reaches the interior of the measuring chamber through one or more component openings and one or more filter openings, rather than through holes in the flow-through filter. The speed with which the gas sample reaches the interior of the measuring chamber can be influenced by various design parameters of the analyzer according to the invention, in particular by the thickness (width) and optionally the geometry of the gap between the filter component and the other component, and by the arrangement and size of the openings.

[0019] In many cases, the analyzer according to the present invention also offers the following advantages, particularly compared to analyzers with flow-through filters: Before the gas sample reaches the measuring chamber, it flows through the gap between the filter element and the further element. The path that the gas sample takes through the gap before reaching the measuring chamber has a length of at least 0.5 cm, preferably at least 2 cm. If multiple openings are present in the filter element and / or the further element, it is feasible for a portion of the gas sample to flow through a first length of at least 0.5 cm, and for another portion of the gas sample to flow through a second length of at least 0.5 cm.

[0020] In many cases, this makes it possible to provide a significantly longer path length, at least 0.5 cm long, compared to a flow-through filter. As the gas sample flows into the measurement chamber, it flows through the chemical filter along this path. Along this path, the chemical filter in or on the filter element can bind or decompose the substance or convert it into a solid form. This reduces the risk of a significant amount of the substance reaching the interior of the measurement chamber. In contrast, if a flow-through filter is used, a portion of the gas sample can flow through the holes in the flow-through filter and, optionally, into the interior of the measurement chamber through an opening that overlaps the holes, without being forced to pass through the gap on its way to the chemical filter.

[0021] Furthermore, the present invention reduces the risk that, under certain circumstances, the chemical filter or another component could become clogged and the gas sample could no longer reach the measuring chamber. This undesirable effect often occurs with flow-through filters, as the pores become increasingly smaller over time and eventually close completely. This effect often occurs, in particular, because flow-through filters can bind to substances to be removed, and these bound substances can thus reduce the pore size—or, more precisely, the area available for flow through.

[0022] Another disadvantage of flow-through filters arises when at least one of the filter's chemical components is hygroscopic and draws in moisture from the environment. Examples of such chemical components are inorganic salts and compounds that chemically bond to the substance to be filtered out. Because the chemical components are hygroscopic and absorb moisture from the environment, the flow-through filter expands. This also causes the pores to become smaller and smaller. Furthermore, the aerodynamic resistance of the flow-through filter increases. One consequence is that flow-through filters can generally only be used in environments with relatively low ambient humidity. The analyzer according to the present invention does not have this disadvantage and can therefore generally also be used in environments with relatively high ambient humidity.

[0023] According to the present invention, the gas sample is forced onto the path through the gap on its path of entering the measuring chamber from the space area to be monitored. This path comprises following road section, and it is at least 0.5cm long, preferably at least 2cm long. In one implementation, filter member, another member and the gap extend along a common longitudinal axis or extend along a plurality of longitudinal axes parallel to each other. Filter member, another member and opening are arranged so as to cause following: the road section of at least 0.5cm in length extends parallel to these parallel longitudinal axes. In another implementation, filter member extends in a plane. The road section of at least 2cm in length is arranged parallel to this plane. In an implementation, this plane is perpendicular to the longitudinal axis of filter member.

[0024] According to the present invention, the filter component includes at least one filter opening. Another component includes at least one component opening. On its path into the measuring chamber, the gas sample flows through the or one component opening and the or one filter opening. Preferably, the or at least one filter opening, preferably each filter opening, has a minimum dimension of at least 0.5 cm, preferably at least 1 cm, and particularly preferably at least 2 cm in a plane perpendicular to the flow direction. The or at least one, preferably each component opening also has a minimum dimension of at least 0.5 cm, preferably at least 2 cm, and particularly preferably at least 5 cm in a plane perpendicular to the flow direction.

[0025] Compared to smaller openings, this design further reduces the risk of the opening being clogged by particles, which could flow through the opening as part of the gas sample and become lodged. This is undesirable because the opening could become clogged, and the gas sample could then only flow into the measurement chamber at a lower volume flow rate, or even not flow at all. Furthermore, advantageous designs typically result in a higher volume flow rate of the gas sample, allowing it to reach the measurement chamber more quickly. This in turn reduces the analyzer's response time, allowing for faster detection of the target gas.

[0026] According to the present invention, filter member and another member jointly (preferably each itself) form a shape-stable member that surrounds (preferably completely surrounds) measuring chamber. Due to shape stability, the risk reduction of a part for filter member or another member entering the measuring chamber. This is undesirable, for example, if the sensor is designed as a photoelectric sensor, and no part should arrive in the optical path between the radiation source and the detector. If the sensor is designed as an electrochemical sensor and no part should contact the electrodes of the electrochemical sensor, this is also undesirable. Filter member or another member should not contact the heating component of the sensor, which can usually be prevented by shape stability. If the chemical filter is, for example, constructed as a piece of cloth or cloth and not held in a specific position by a shape-stable member, the risk of a part for filter member and therefore a part for possible chemical filter arriving in the inside of the measuring chamber can become larger.

[0027] It is feasible that the filter member surrounds the other member. On the contrary, preferably, the other member surrounds the filter member, more precisely, completely surrounds the filter member. This design can realize that the user can replace the filter member and therefore replace the chemical filter in many cases without directly contacting the chemical filter, more precisely, when the filter member is firmly connected to the other member. Such contact may cause undesirable consequences to the user's skin and / or damage the chemical filter. This design solution makes it possible to prevent these undesirable consequences without the user having to wear suitable protective equipment such as gloves. In this application, the other member surrounding the filter member also serves as a handle guard.

[0028] In one design, a dimensionally stable filter component and a dimensionally stable further component together form a dimensionally stable module. The filter component, and therefore the chemical filter, cannot change its position relative to the other component. This design further reduces the risk of the filter component or the other component entering the measurement chamber. Furthermore, a dimensionally stable module can generally be replaced more quickly than if the chemical filter and the other component were replaced separately.

[0029] According to the present invention, the filter member comprises a chemical filter. In one design, the filter member is a dimensionally stable member as a whole. In another design, the chemical filter is not necessarily dimensionally stable, and the filter member also comprises a dimensionally stable support for maintaining the chemical filter.

[0030] According to the present invention, the filter element comprises a chemical filter. In one embodiment, the entire filter element serves as the chemical filter. In another embodiment, the filter element comprises another part in addition to the chemical filter. The chemical filter is securely connected to the other part. For example, the other part is dimensionally stable, and the chemical filter is applied to the surface of the dimensionally stable other part, for example as a coating.

[0031] According to the invention, the filter element has at least one opening, which is referred to as the filter opening. Different designs are possible for installing the or a filter opening there.

[0032] In a preferred embodiment, the filter element has two end faces and a peripheral surface between the two end faces. The two end faces are, for example, circular or more generally elliptical, and the filter element has, for example, a cylindrical or truncated cone shape. It is also possible that each end face has an n-gonal shape, where n>=3 is the number of corners. Preferably, the two end faces are perpendicular to the longitudinal axis and therefore perpendicular to the central axis of the filter element.

[0033] In one implementation, the or at least one filter opening is embedded in the peripheral surface. Then, the gap and therefore the at least 0.5 cm long section along which the gas sample flows through the gap is preferably parallel to the filter longitudinal axis and / or parallel to the peripheral surface. In another implementation, the or at least one filter opening is embedded in the end face. It is even feasible that the end face forms the filter opening as a whole. If the or one filter opening is embedded in the end face, the 0.5 cm long section is preferably perpendicular to the filter longitudinal axis. In a refinement of this implementation, the peripheral surface is impermeable to gas, and a chemical filter is placed on the peripheral surface, or the peripheral surface forms a chemical filter.

[0034] These two forms of implementation can be combined with one another. It is also possible that the or each filter opening is embedded in the circumferential surface and that the two end faces are impermeable to gas.

[0035] The measuring chamber is preferably surrounded by a measuring chamber housing. The measuring chamber housing encloses the measuring chamber, the filter element, and the further element. In one embodiment, both elements are dimensionally stable, and the dimensionally stable chemical filter element and the dimensionally stable further element are releasably insertable into the measuring chamber housing, thereby enabling rapid replacement of the two dimensionally stable elements.

[0036] The measuring chamber housing protects the filter element and thus the chemical filter and the other component to a certain extent from external mechanical and chemical influences, in particular weather influences, contamination and mechanical damage. It is possible that the filter element is inserted into the measuring chamber housing. It is also possible that a part of the measuring chamber housing simultaneously forms the other component.

[0037] Preferably, the measuring chamber housing is detachably connected to another housing of the analyzer. After the user removes the measuring chamber housing from the other housing, the filter component and therefore the chemical filter in the measuring chamber housing can be replaced.

[0038] It is feasible that the gas sample reaches the measuring chamber only by diffusion. It is also feasible that a fluid delivery unit (e.g., a blower, a pump, or a piston-cylinder unit) delivers the gas sample into the measuring chamber (e.g., by suction). In contrast, in a preferred design, convection is caused to flow out of and into the measuring chamber. To cause convection, two openings are embedded in the measuring chamber housing. The gas sample flows into the measuring chamber through one opening and flows out of the measuring chamber again through the other opening. According to a preferred implementation, the lower opening and the upper opening are embedded in the measuring chamber housing. When the analyzer is used as specified, the lower opening is located vertically or obliquely below the upper opening.

[0039] In designs with induced convection, the analyzer further includes a heatable element. This heatable element is in thermal contact with the measuring chamber and, for example, is arranged within the interior of the measuring chamber. When the heatable element is heated, the gas in the measuring chamber heats up. This reduces the density of the gas in the measuring chamber, making it lighter than the surrounding gas. This in turn causes a corresponding amount of gas to escape from the measuring chamber through the upper opening. This in turn causes additional gas to flow into the measuring chamber from below through the lower opening. Heating thus induces convection, also known as the chimney effect.

[0040] Designs that induce convection have the following advantages over designs in which the gas sample reaches the measurement chamber solely by diffusion: Due to convection, the gas sample reaches the measurement chamber faster than by diffusion alone, and the analyzer can detect the target gas in the gas sample more quickly. Designs that induce convection also eliminate the need for a fluid transport unit. Fluid transport units inevitably include at least one component that moves during continuous operation and are therefore more susceptible to failure than heatable elements.

[0041] The following disadvantages of analyzers with flow-through filters have already been mentioned above. In particular, the pores of flow-through filters can become clogged during use, and the aerodynamic resistance is often greater than with the solution according to the present invention. Furthermore, in many cases, flow-through filters can only be used in relatively low ambient humidity. In many cases, these disadvantages also occur in analyzers that include flow-through filters and induce convection. Often, the increasingly smaller pores even lead to the complete elimination of the associated convection.

[0042] In many cases, however, the analyzer according to the present invention, which has a filter element, a further element, and a gap, can fully utilize the effects of convection and the resulting advantages for a longer period of time than when using a flow-through filter, specifically even at relatively high ambient humidity. Flow-through filters generally have a high aerodynamic flow resistance, and their pores can become clogged. Consequently, convection is generally interrupted relatively quickly, while the analyzer according to the present invention can be used for a longer period of time without having to replace the chemical filter.

[0043] Different designs are possible: how the sensor measures the concentration of the target gas to be detected in the gas sample when the gas sample is located in the measurement chamber.

[0044] In one embodiment, the sensor is designed as an electrochemical sensor, which preferably operates in the manner of a fuel cell. An electrochemical sensor comprises a measuring electrode, a reference electrode, and an ionically conductive electrolyte between the two electrodes. The target gas to be detected causes an electrochemical reaction, and due to this electrochemical reaction, a current flows from one electrode to the other. A measure of the charge is measured. The charge is correlated with the desired concentration of the target gas in the gas sample.

[0045] In other designs, the analyzer includes a detector and a compensator. Both the detector and the compensator are heated. The heated detector oxidizes the combustible target gas in the measurement chamber, thereby releasing heat energy, which further heats the detector. The heated compensator can oxidize the combustible target gas to a lower degree than the heated detector, or the amount of gas sample reaching the compensator per unit time is less than the amount of gas sample reaching the detector. The detection variable sensor measures a measure of the heating of the detector and therefore of the released heat energy. This measure is related to the target gas concentration being sought. Ideally, the compensator can computationally compensate for the effects of ambient conditions on the heating of the detector. Such sensors are also known as thermoacoustic sensors or catalytic sensors.

[0046] A design has already been described above in which the analyzer induces convection using a heatable element. This design with convection can be combined with the design just described, in which the analyzer includes a detector and a compensator. In this combination, the detector and / or the compensator preferably serves as the or one of the heatable elements. This type of combination utilizes the advantages of convection without the aforementioned disadvantages of flow-through filters and eliminates the need for an additional heatable element.

[0047] In another embodiment, the sensor is designed as a photoelectric sensor and includes a radiation source, a measuring detector, and preferably a reference detector. The radiation source emits electromagnetic radiation, preferably radiation in the infrared range, into a measuring chamber. The radiation penetrates the gas sample in the measuring chamber at least once. The target gas to be detected attenuates the intensity of the electromagnetic radiation in a specific wavelength range. After penetrating the gas sample at least once, the radiation impinges on the measuring detector and, optionally, a reference detector. The measuring detector and the reference detector each measure a measure of the intensity of the impinging radiation. The intensity of the impinging radiation is a measure of the desired target gas concentration. Ideally, the reference detector can computationally compensate for the effects of ambient conditions (particularly water droplets) on the measurement results. In one embodiment, a wavelength filter preceding the measuring detector passes only electromagnetic radiation in the wavelength range that attenuates the radiation of the target gas. A wavelength filter preceding the reference detector passes radiation in a different wavelength range. The sensor can also include two measuring detectors for two different target gases, wherein a wavelength filter is particularly preferably disposed in front of each measuring detector, and the two wavelength filters pass radiation in two different wavelength ranges.

[0048] In a preferred embodiment, the optical path of the electromagnetic radiation through the measuring chamber is extended in that a mirror in or at the measuring chamber reflects the radiation at least once and the radiation thus passes through the gas sample at least twice.

[0049] Implementations with mirrors can be combined with the design described above, where a heatable element can generate convection. This combination is described below. The heatable element also carries the mirror. In this combination, heating the heatable element causes the gas in the measurement chamber to heat up. Because the heatable element also carries the mirror, the risk of condensation on the mirror or on other walls of the measurement chamber is reduced. Condensation or condensed water can reduce the mirror's ability to reflect radiation and potentially cause corrosion.

[0050] A design was described above in which a lower opening and an upper opening are embedded in the measuring chamber housing. Heating the gas in the measuring chamber causes the gas to flow from the lower opening through the measuring chamber to the upper opening due to convection (the chimney effect), thereby rapidly filling the measuring chamber with the gas sample to be tested. This design can be combined with an embodiment in which the sensor is a photoelectric sensor and the heatable element carries a mirror.

[0051] Furthermore, a design is described above in which the measuring chamber housing is connected to another housing, preferably releasably. The measuring chamber, the chemical filter, and another component are arranged in the measuring chamber housing. This design can be combined with a design in which the sensor is designed as a photoelectric sensor. The optional mirror described above is arranged in the measuring chamber housing. The radiation source, the measuring detector, and an optional reference detector are arranged in the other housing. Preferably, the other housing is fluid-tight, and the measuring chamber is separated from the interior of the other housing in a fluid-tight manner. The emitted electromagnetic radiation penetrates a fluid-tight window in the other housing, then penetrates the measuring chamber once, is reflected at the mirror, penetrates the measuring chamber again, then penetrates the one or another fluid-tight window again and impinges on the one or each measuring detector and the optional reference detector. The other housing protects the radiation source and the detector from external mechanical and chemical influences. Optionally, an additional voltage supply unit is housed in the other housing. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The present invention will be described below based on the following embodiments.

[0053] Figure 1 The analyzer according to the invention with a photoelectric sensor is shown in a perspective view;

[0054] Figure 2 The measuring chamber, the filter element and the path of the gas sample are schematically shown in a cross-sectional view, wherein the filter opening is embedded in the peripheral surface of the chemical filter;

[0055] Figure 3 Shown Figure 2 A variant of the design scheme, wherein the two end faces of the filter component form the filter opening of the chemical filter;

[0056] Figure 4 The cross-sectional view shows the Figure 1 A weatherproof cap (Wetterschutzkappe) of an embodiment and corresponding paths for the gas sample and water;

[0057] FIG5 schematically shows an analyzer according to the present invention having a thermal sound sensor;

[0058] Figure 6 The measurement results involving the response time of the analyzer are shown. DETAILED DESCRIPTION

[0059] Figure 1 Two perspective views illustrate an analyzer 100 according to this embodiment. The analyzer 100 is capable of detecting at least one predetermined target gas. In this embodiment, the analyzer 100 is capable of measuring the concentration of the target gas in a gas sample. The target gas may be, for example, methane or carbon monoxide, a gas harmful to the human body, or oxygen, carbon dioxide, or an anesthetic. In this embodiment, the target gas absorbs a portion of electromagnetic radiation within a specific wavelength range, while the radiation penetrates the target gas and thereby attenuates the electromagnetic radiation.

[0060] The analyzer 100 can be fixed to a wall or to a user's protective clothing by means of an optional bracket 15. The terms "lower" and "upper" used below refer to the orientation of the analyzer 100 in use. The figure shows the analyzer 100 in this orientation.

[0061] according to Figure 1 The analyzer 100 includes

[0062] - a solid fluid-tight housing 2, for example made of metal,

[0063] - Weatherproof cap 1; and

[0064] - A removable voltage supply unit 6 in its own housing.

[0065] In this embodiment, a solid-state housing 2 is positioned between a weather cap 1 and a voltage supply unit 6. Weather cap 1 has a shape approximately like a truncated cone and is approximately rotationally symmetrical about a central axis MA. Both weather cap 1 and voltage supply unit 6 can be separated from and reattached to housing 2. The positioned weather cap 1 surrounds a region of housing 2 that has a smaller diameter than the remainder of housing 2. Preferably, mechanical coding ensures that weather cap 1 can only be pushed onto housing 2 in a specific rotational position relative to housing 2.

[0066] exist Figure 1 The upper center section shows the interconnectedness of the three components 1, 2, and 6, while the lower section shows the weather cap 1 removed from the housing 2 and the voltage supply unit 6 omitted. A U-shaped mirror holder 3 with two arms 3.1 and 3.2 securely holds the mirror 5 to the housing 2. The attached weather cap 1 surrounds the mirror 5 and the mirror holder 3.

[0067] Figure 2 and Figure 3 The interior of the weatherproof cap 1 is schematically shown in a cross-sectional view. A measuring chamber 30 and a mirror 5 are arranged in the interior of the weatherproof cap 1. In the embodiment shown, the measuring chamber 30 has a cylindrical shape and extends along a central axis MA.

[0068] The photoelectric sensor 50 includes a radiation source 10 and a detector component 11. The radiation source 10 and the detector component 11 are arranged inside the housing 2. The detector component 11 includes a measuring detector, a reference detector, a wavelength filter in front of the measuring detector, and preferably a wavelength filter in front of the reference detector. The wavelength filter in front of the measuring detector only allows electromagnetic radiation in a wavelength range that attenuates the electromagnetic radiation of the target gas to be detected to pass through. The wavelength filter in front of the reference detector allows electromagnetic radiation in a different wavelength range to pass through. It is feasible that two measurement methods arranged in parallel can detect two different target gases, wherein two wavelength filters are arranged in front of the two measuring detectors to allow electromagnetic radiation in two different wavelength ranges to pass through.

[0069] A gas sample containing or potentially containing at least one target gas to be detected is present in measurement chamber 30. Radiation source 10 emits electromagnetic radiation eS, preferably in the infrared range. The emitted electromagnetic radiation eS penetrates window 4 in housing 2 once, then penetrates measurement chamber 30, is reflected by mirror 5, penetrates measurement chamber 30 and window 4 again, and impinges on detector element 11. Mirror 5 doubles the optical path length.

[0070] Not only the measuring detector of the detector assembly 11 but also the reference detector of the detector assembly 11 respectively measures the intensity of the electromagnetic radiation that impinges. Due to the wavelength filter in front of the measuring detector, the signal of the measuring detector is related to the target gas concentration in the gas sample Gp. However, the signal of the measuring detector is usually also affected by the environmental conditions, in particular by the environmental humidity, and therefore by any water droplets or water vapor in the measuring chamber 30. In particular, water droplets can also attenuate electromagnetic radiation. Ideally, the reference detector reacts to the influence of environmental conditions in the same way as the measuring detector, but due to the wavelength filter in front of the reference detector, it is not affected by the target gas. The signal of the reference detector is used to compensate for the influence of environmental conditions on the signal of the measuring detector in a computational manner.

[0071] Undesirable events can occur, such as water vapor condensing on the mirror 5 or another wall of the measuring chamber 30. This condensed water can distort the measurement results and may also cause undesirable corrosion. The following describes how the risk of this undesirable event can be reduced in an embodiment. According to this remedy, the mirror frame 3 is heated, for example, by means of a heating wire inside the frame 3. Heating the frame 3 reduces the risk of water condensing on the mirror 5 or another wall of the measuring chamber 30.

[0072] Heating the mirror holder 3 has a further desired effect as follows: the heating causes the gas inside the measuring chamber 30 to be heated. The heating reduces the density of the gas and causes the so-called chimney effect, also known as convection. Due to the convection, the gas sample Gp enters the measuring chamber 30 from below and leaves the measuring chamber 30 again upwards. Due to the convection, the gas sample Gp reaches the measuring chamber 30 faster than if the gas sample Gp had arrived in the measuring chamber 30 only by diffusion. This in turn leads to faster detection of the target gas in the gas sample Gp, or faster exclusion of the gas sample Gp from containing the target gas or gases. Due to the convection, there is no need to use a separate fluid transport unit, wherein the fluid transport unit draws in and / or discharges the gas sample Gp. Such a fluid transport unit inevitably consumes electrical energy, takes up structural space and must be monitored.

[0073] Figure 2 、 Figure 3 and Figure 4 The path of the gas sample Gp through the interior of the weatherproof cap 1 is shown in two cross-sectional views. A lower opening 8 and an upper opening 7 are provided in the weatherproof cap 1. The gas sample Gp enters the interior of the weatherproof cap 1 through the lower opening 8, flows through the weatherproof cap 1 in a tortuous path, and exits the weatherproof cap 1 again through the upper opening 7. This tortuous path is forced by corresponding components in the interior of the weatherproof cap 1.

[0074] Water can penetrate into the interior of the weatherproof cap 1 through the upper opening 7. Therefore, there is a waterproof barrier 9 below the upper opening 7, see Figure 4 The waterproof barrier 9 surrounds the measuring chamber 30 depending on the type of tube and prevents water from penetrating into the measuring chamber 30 . Figure 3 The path H2O of water in and out of the weatherproof cap 1 is schematically shown in FIG.

[0075] In addition to the target gas and water droplets, the gas sample Gp may also contain substances that differ from the or each target gas and should not affect the measurement results of the analyzer 100. Such substances are, for example, hydrogen sulfide or long-chain hydrocarbons. It is possible that such substances are harmful to components in the weatherproof cap 1 and / or in the measurement chamber 30. Therefore, the measures described below can be used to prevent such substances from reaching the interior of the measurement chamber 30.

[0076] The measuring chamber 30 is surrounded by the chemical filter 22. Figure 2 In the design of the entire filter element 20 acts as a chemical filter 22. Figure 3 In the embodiment described in more detail below, a portion of the filter element 20 is used as a chemical filter 22. Figure 3 In the embodiment of the present invention, the remainder of the filter element 20 is chemically inactive.

[0077] In this embodiment, the filter member 20 has a shape of a tube or a truncated cone. Figure 3 and Figure 4 A tubular (columnar) filter member 20 is schematically shown, having two mutually parallel circular end faces 20.S1 and 20.S2 and a peripheral surface 20.M between the two end faces 20.S1 and 20.S2. In the example shown, the filter member 20 is shape-stable and includes a body made of, for example, a polymer or other solid plastic, metal, or glass. For example, the filter member 20 is manufactured by sintering or 3D printing. In one design, the filter member 20 is held in position relative to the weatherproof cap 1 by its own elasticity. In another design, it is held in position by a screw closure, a snap closure, a latch closure, or by appropriate protrusions and grooves. In particular, these preferred design solutions prevent the filter member 20 from reaching the optical path from the radiation source 10 via the mirror 5 to the member 11.

[0078] Multiple openings Embedded in the filter member 20, the plurality of openings serve as filter openings. Figure 2 and Figure 3 The two embodiments differ from each other as follows: Figure 2 In the design, the filter opening It has a curved rectangular shape and is embedded in the peripheral surface 20 of the filter member 20. Figure 3 In the design, two filter openings Embedded in the two end faces 20.S1 and 20.S2, wherein preferably the two end faces 20.S1 and 20.S2 simultaneously form two filter openings Naturally, other geometries are also possible.

[0079] The gas sample Gp enters the interior of the weatherproof cap 1 through the lower opening 8 and passes through the opening Enter the measuring chamber 30. The filter element 20 is ideally - except for the opening In addition - it is impermeable to gases. In practice, the filter element 20 generally has unavoidable additional openings.

[0080] In an embodiment, the filter member 20 is surrounded by another member 21. In this embodiment, a portion of the housing 2, the mirror 5, and the member 21 in the shape of a tube or truncated cone together serve as another member. The tubular member 21 extends along the central axis MA. Preferably, the tubular member 21 also serves as a handle protector and is particularly preferably securely connected to the filter member 20. Hereinafter, the term "handle protector" will be used for the other member 21, even if the other member 21 does not serve as a handle protector. In this embodiment, the handle protector 21 has the same geometry as the filter member 20, but has a larger diameter, so that a surrounding cylindrical gap Sp.i (inner gap) appears between the filter member 20 and the handle protector 21. A surrounding gap Sp.a (outer gap) appears between the handle protector 21 and the weatherproof cap 1. In one embodiment, the surrounding outer gap Sp.a increases toward the housing 2. In another embodiment, the surrounding outer gap Sp.a always has the same width along the central axis MA.

[0081] In one embodiment, the filter element 20 and the handle guard 21 together form a dimensionally stable module. For example, the two elements 20 and 21 are firmly connected to each other.

[0082] The handle guard 21 is also impermeable to gases. Arranged in the handle guard 21. In the example shown, the opening Embedded in the circumference of another cylindrical member 21. Handle protector 21 is held in a fixed position relative to weatherproof cap 1 by its own elasticity and / or by the protrusions and grooves, and filter member 20 is also held in a fixed position relative to handle protector 21. Thus, neither filter member 20 nor handle protector 21 can change their respective positions relative to weatherproof cap 1, and neither filter member 20 nor handle protector 21 can enter the aforementioned optical path through measurement chamber 30.

[0083] In accordance with Figure 2 In the embodiment of the present invention, the opening in the filter member 20 With respect to the opening in the handle guard 21 Displacement (lateral offset), more precisely parallel to the center axis MA. It is also possible that, in addition to or instead of parallel displacement, the opening and The arrangement can also be twisted relative to each other around the central axis MA. Figure 3 In the embodiment of the present invention, the entire circumferential surface 20.M of the filter element 20 is impermeable to gases, while the two end surfaces 20.S1 and 20.S2 are permeable to gases. The chemical filter 22 is applied to the circumferential surface 20.M and cannot change its position relative to the circumferential surface 20.M.

[0084] In addition to the openings just mentioned, not only the filter element 20 but also the handle protection 21 is impermeable to gases. Therefore, on its way from the lower opening 7 to the upper opening 8, the gas sample Gp is ​​forced to follow the following path:

[0085] - First through the opening in the handle guard 21

[0086] - then approximately parallel to the central axis MA through the inner gap Sp.i, and

[0087] - then through the opening in the filter member 20 Enter into the interior of the measuring chamber 30 .

[0088] Therefore, the gas sample Gp flows in the inner gap Sp.i and passes through the chemical filter 22 on the outside.

[0089] In particular, due to the opening and do not overlap, thus preventing the following undesirable event from occurring: a portion of the gas sample Gp flows through the lower opening 7 and through the opening and into the interior of the measuring chamber 30 without flowing through the filter member 20. This would result in a large amount of material passing through the chemical filter 22 into the measuring chamber 30, which is undesirable.

[0090] Therefore, the gas sample Gp flows through the chemical filter 22 on its way through the inner gap Sp.i. The section of the path that the gas sample Gp travels in the gap Sp.i depends on the opening and The path into the inner gap Sp.i onto which the gas sample Gp is ​​forced comprises a section that is at least 0.5 cm, preferably at least 2 cm, particularly preferably at least 5 cm, in particular at least 10 cm long.

[0091] The duration of the gas sample Gp's presence in the inner gap Sp.i depends on this path length and the thickness and geometry of the gap Sp.i. Chemical filter 22 binds molecules of substances in the gas sample Gp that should not reach the interior of measurement chamber 30. Ideally, such substances accumulate only outside chemical filter 22. The binding of substance molecules by chemical filter 22 creates a concentration gradient in the gas sample Gp. This causes more molecules of the substance to migrate toward chemical filter 22 and also bind there. Naturally, these effects only occur if the gas sample Gp contains the substance in question.

[0092] In one application, hydrogen sulfide is harmful to at least one component of the detector assembly 11. Therefore, hydrogen sulfide should be prevented from reaching the interior of the measurement chamber 30. In one embodiment, the chemical filter 22 includes an alkaline copper salt. Hydrogen sulfide binds to the alkaline copper salt, and the copper salt is converted into solid copper sulfide.

[0093] In one application, carboxylic acids, such as acetic acid (CH3COOH), should be prevented from reaching the interior of measuring chamber 30. Carboxylic acids are particularly corrosive to metals and can therefore cause malfunctions in sensors 10, 11. For example, corrosion can damage the measuring element, window, mirror mount, and / or mirror coating. Alkali metal hydroxides neutralize carboxylic acids in various ways. For example, a chemical filter 22 containing potassium hydroxide neutralizes acetic acid by converting it into solid potassium acetate (C2H3KO2).

[0094] It is generally necessary to replace the chemical filter 22 from time to time. To replace the chemical filter 22, the user performs the following steps:

[0095] The user pulls the weather cap 1 out of the housing 2 . The mirror 5 holds the filter element 20 and the handle protector 21 at the housing 2 and prevents the element 20 or 21 from being pulled out of the housing 2 together with the weather cap 1 .

[0096] The user pulls the handle protector 21 together with the filter element 20 away from the housing 2 , more precisely in a direction parallel to the central axis MA.

[0097] Providing a new chemical filter 22. It is possible to provide a new filter element 20. It is also possible to apply a new chemical filter 22 to a removed filter element 20.

[0098] The filter element 20 with the new chemical filter 22 is already or is surrounded by the old or new handle guard 21 .

[0099] The user pushes the filter element 20 with the new chemical filter 22 toward the housing 2 until the housing 2 holds the filter element 20 with the new chemical filter 22. For example, a locking connection or a snap-on connection is established. During this movement, the handle guard 21 surrounds the filter element 20.

[0100] The handle guard 21 prevents the user from coming into contact with the chemical filter 22. Such contact could have an undesirable effect on the skin of the user's hand and / or damage the chemical filter 22.

[0101] The user places the weather cap 1 on the housing 2 and thereby on the components 20 and 21 .

[0102] It is also possible that the weatherproof cap 1 holds the components 20 and 21 inside and the components 20 and 21 are pulled out of the housing 2 together with the weatherproof cap 1. Some steps in the sequence just described would be modified accordingly. In particular, the user would then pull the components 20 and 21 out of the weatherproof cap 1.

[0103] In an alternative embodiment, the filter element 20 is not securely connected to the handle guard 21. Instead, the handle guard 21 is secured to the interior of the weatherproof cap 1 and, when the weatherproof cap 1 is pulled out, the handle guard 21 is also pulled out of the housing 2. The filter element 20 initially remains in the housing 2 and can be pulled out and replaced separately. This design allows the filter element 20 to be replaced independently of the handle guard 21, which is particularly advantageous if the chemical filter 22 must be replaced more frequently than the handle guard 21.

[0104] Figure 4 FIG2 shows two indicator lights 40 and 41 on the housing 2. When the analyzer 100 is turned on and the voltage supply unit 6 provides sufficient power, the indicator light 40 illuminates. When the analyzer 100 has detected a fault, the indicator light 41 illuminates. Examples of such faults are:

[0105] - Although the analyzer 100 is switched on, the weather cap 1 is not correctly mounted on the housing 2, or is not even mounted on the housing 2 at all. Alternatively, the filter element 20 is not correctly connected to the housing 2 and / or is not correctly inserted into the weather cap 1. In both cases, a portion of the gas sample Gp can pass through the chemical filter 20 and reach the interior of the measurement chamber 30, thus bypassing the chemical filter 20. In one implementation, the undesirable event that the weather cap 1 is not correctly positioned is detected by means of a contact switch (not shown).

[0106] The assembly comprising the filter element 20 with the chemical filter 22 and the handle guard 21 is not inserted into the interior of the weatherproof cap 1. This event is also detected, for example, using a contact switch. Alternatively, a machine-readable identifier is applied to the outside of the handle guard 21, for example in the form of an RFID chip or other NFC chip or a barcode. A reader (not shown) in the interior of the weatherproof cap 1 detects this machine-readable identifier. If the reader does not detect this machine-readable identifier, the handle guard 21 and therefore the chemical filter 22 are missing. Alternatively, the weatherproof cap 1 is incorrectly positioned.

[0107] - The opening 7 or 8 for convection is blocked.

[0108] In one embodiment, a machine-readable identifier on the handle guard 21 uniquely identifies the component having the chemical filter 22 and the handle guard 21. The point in time at which the reader first records the machine-readable unique identifier is stored in the data memory of the analyzer 100. The control unit measures the time period that has elapsed since this point in time of insertion, i.e. the duration of use to date. Preferably, for this time period, only those time periods in which the analyzer 100 is switched on are taken into account. If the time period exceeds a preset lower duration limit, a message is generated and output in at least one form perceptible to humans. This message is an indication that the chemical filter 22 is now used up and must be replaced. How to replace the chemical filter 22 has already been described above.

[0109] The detector assembly 11 includes a measuring detector and a reference detector. A wavelength filter is placed before the measuring detector, which only allows electromagnetic radiation in a wavelength range where the target gas absorbs electromagnetic radiation, thereby reducing the radiation intensity. A wavelength filter is placed before the reference detector, allowing radiation in a different wavelength range to pass. In one embodiment, these other wavelength ranges include the wavelength range of water and the wavelength range of substances that should not reach the measuring chamber 30. It is also possible to use two reference detectors, with a wavelength filter for water placed before the first reference detector and a wavelength filter for undesirable substances placed before the second reference detector. In some cases, by evaluating the signals generated by the detector assembly 11, it is possible to automatically determine whether a relevant amount of a substance has entered the measuring chamber 30. If a relevant amount has entered the measuring chamber 30, this indicates that the chemical filter 22 should be replaced. The analyzer 100 displays a corresponding message.

[0110] replace Figure 2 and Figure 3 The analyzer 100 may include a photoelectric sensor 50, a thermal sound sensor 51. FIG5 schematically shows three exemplary embodiments of such a thermal sound sensor 51 as a component of the analyzer 100 according to the invention. Figure 2 and Figure 3 The same meaning in .

[0111] The thermal sound sensor 51 includes a housing 2, a detector 31 and a compensator 32. The housing opening in the housing 2 A fluid connection is established between the measuring chamber 30 in the interior of the housing 2 and the environment. The detector 31 is heated. The heated detector 31 oxidizes the combustible target gas in the measuring chamber 30 - this naturally only occurs when there is enough combustible target gas in the measuring chamber 30. The oxidation of the target gas releases thermal energy, which further heats the detector 31. The released thermal energy changes a detection variable related to the temperature of the detector 31, such as resistance. As is well known, in many conductive components, the resistance increases when the temperature rises. The detection variable sensor measures a measure for the temperature of the detector 31. The measured detection variable is a measure for the detector temperature and, therefore, a measure for the target gas concentration being sought. By way of example, a voltage sensor 34 is shown, which measures the voltage present at the detector 31.

[0112] The temperature of detector 31 is affected not only by the target gas concentration but also by ambient conditions, particularly ambient temperature and humidity. Compensator 32 may oxidize the combustible target gas to a lesser extent than detector 31, or even not at all, but ideally reacts to the same ambient conditions. The detection variable of compensator 32 is measured. For example, a voltage sensor 35 is shown, which measures the voltage present at compensator 32. The compensator detection variable can be used to computationally compensate for the influence of ambient conditions on the detector detection variable to a certain extent.

[0113] In this embodiment, both the detector 31 and the compensator 32 each have the form of a catalytic burner (Pellistor). A nearly spherical ceramic housing surrounds the heating section. The ceramic housing chemically and electrically isolates the heating section from the environment while establishing thermal contact. The catalytic substance is embedded in the housing of the detector 31, but not in the housing of the compensator 32.

[0114] In one embodiment, the detector 31 and optionally the compensator 32 act simultaneously as heatable elements, e.g. Figure 4 As shown in FIG, it causes convection to enter the measuring chamber 30 through the lower opening 8 and leave the measuring chamber 30 through the upper opening 7. When the analyzer 100 is in use, the housing opening It is preferably located below the measuring chamber 30 .

[0115] exist Figure 5a )and Figure 5b ) in the example, the filter member 20 with the chemical filter 22 is located in the housing opening Between the filter element 20 and the other element 21. The inner gap Sp.i is located between the filter element 20 and the other element 21. Figure 5a ) example, the filter opening It is located between a filter element 20 that is impermeable to gas and another element 21. The gas sample Gp flows around the filter element 20 and passes through the filter openings there. and then through the inner gap Sp.i and through the opening Enter the measuring room 30. Figure 5b ) example, the filter opening is embedded in the filter member 20, and the gas sample Gp flows through the filter opening and the inner gap Sp.i into the measuring chamber 30 .

[0116] On the contrary, Figure 5c ), the housing 2 itself acts as another member 21. An inner gap Sp.i appears between the housing 2 and the filter member 20. The chemical filter 22 is arranged at the filter member 20 and points toward the housing opening. It also serves as an opening for another component 21

[0117] Figure 6 The diagram illustrates the results of in-house experiments conducted by the inventors. The results show different response times. The time elapsed since the analyzer 100 was switched on is plotted on the x-axis (in minutes:seconds). The relative target gas concentration con (in %) measured at the corresponding time point is plotted on the y-axis. A value of 1 = 100% indicates that the maximum measured value has been reached. Ideally, this maximum measured value corresponds to the actual concentration of the target gas in the gas sample Gp. Some time inevitably elapses between the time the analyzer 100 is switched on and the time the gas sample Gp fills the measurement chamber 30. Consequently, time also elapses until the maximum value is reached.

[0118] In a first internal experiment, the analyzer 100 was used without a chemical filter, in a second internal experiment, the analyzer 100 was used with a filter with holes, wherein the gas sample flowed through the holes (flow-through filter), and in a third internal experiment, the analyzer 100 according to the present invention was used. Figure 6 In the figure, three measurement curves Vo, V.trans, and V.inv are drawn:

[0119] The measurement curve Vo refers to the first internal experiment (analyzer without chemical filter), the measurement curve V.trans refers to the second internal experiment (analyzer with flow-through filter), and the measurement curve V.inv refers to the analyzer 100 according to the present invention. Furthermore, three time points t, t.trans, and t.inv are entered. At these time points, the corresponding measurement curve reaches a value of 0.9, which is 90% of the maximum value.

[0120] As expected, the response time is shortest in an analyzer without a chemical filter. However, without a chemical filter, it is undesirable for substances to reach the measurement chamber 30. It can be seen that the chemical filter 22 arranged according to the present invention significantly reduces the response time compared to an analyzer with a flow-through filter. By way of example, internal experiments indicate that the present invention reduces the response time and, therefore, leads to faster detection of the target gas without substances reaching the measurement chamber 30 and distorting the measurement results.

[0121] List of reference numerals:

[0122] The weatherproof cap has an approximately truncated cone shape and can be inserted into and removed from the housing 2. It surrounds the measuring chamber 30, receives the filter element 20 and the handle protection 21, and serves as the measuring chamber housing.

[0123] 2 housing made of metal, receiving the radiation source 10 and the component 11 with the measuring detector and the reference detector, which can be releasably connected to the weatherproof cap 1 and the voltage supply unit 6, and has a window 4

[0124] 3 Mirror frame for mirror 5, including arms 3.1 and 3.2, which also serve as heatable elements, connected to housing 2

[0125] 3.1, 3.2 Arm of mirror frame 3

[0126] 4 A window in the housing 2 allows electromagnetic radiation eS to pass through the measurement chamber inside the weatherproof cap 1

[0127] 5 Mirror inside the weatherproof cap 1, held by the mirror holder 3

[0128] 6 Voltage supply unit with its own housing, which can be releasably connected to the housing 2 7 Upper opening in the weatherproof cap 1

[0129] 8 Lower opening in weatherproof cap 1

[0130] 9 Waterproof barrier inside the storm cap 1

[0131] 10 radiation source, emitting electromagnetic radiation eS through the window 4 into the measurement chamber 30

[0132] 11 detector assembly with measuring and reference detectors and wavelength filters

[0133] 15 The bracket at the housing 2 enables the analyzer 100 to be assembled

[0134] 20 filter member, surrounding the measuring chamber 30, surrounded by the handle protection 21, including a chemical filter 22, having end surfaces 20.S1, 20.S2, a peripheral surface 20.M and an opening

[0135] 20.S1, 20.S2 End surface of filter component 20

[0136] 20.M Surface of filter element 20

[0137] 21 handle protection member 21, surrounds the filter member 20, has an opening Serves as another component

[0138] 22 Chemical filter, belonging to filter component 20

[0139] 30 Measuring chamber inside weatherproof cap 1

[0140] 31 The detector of the thermal sound sensor 51 oxidizes the combustible target gas and is further heated thereby

[0141] 32 The compensator of the thermoacoustic sensor 51 is not or is less able to oxidize the combustible target gas than the detector

[0142] 34 voltage sensor, measuring the voltage at detector 31

[0143] 35 voltage sensor, measuring the voltage at the compensator 32

[0144] 40 indicator light: analyzer 100 is connected

[0145] 41 indicator light: fault

[0146] 50 Photoelectric sensor, including radiation source 10, mirror 5 and detector component 11

[0147] 51 Thermal sound sensor, including detector 31, compensator 32 and voltage sensors 34 and 35

[0148] 100 analyzer, including a weatherproof cap 1, a housing 2, a sensor 50 or 51 and a voltage supply unit 6

[0149] eS electromagnetic radiation, emitted by radiation source 10

[0150] The flow path of the Gp gas sample passes from bottom to top through the weatherproof cap 1 and the measurement chamber 30

[0151] H2O water flow path through the weatherproof cap 1

[0152] The central axis of the MA cylindrical measuring chamber 30 is the central axis of the weatherproof cap 1

[0153] Tubular inner gap between the Sp.i filter member 20 and the handle protector 21

[0154] Sp.a outer gap between the weather cap 1 and the handle protector 21, which increases towards the housing 2 in one embodiment and remains constant along the central axis MA in another embodiment

[0155] The following time point of the t.inv measurement curve V.inv, at which the measured target gas concentration reaches 90% of the maximum value

[0156] The following time point of the measurement curve Vo is when the measured target gas concentration reaches 90% of the maximum value

[0157] The following time point of the t.trans measurement curve V.trans, when the measured target gas concentration reaches 90% of the maximum value

[0158] V.inv is a measurement curve of the relative target gas concentration over time for the analyzer in the chemical filter 22 arranged according to the present invention

[0159] Vo measurement curve of relative target gas concentration over time for an analyzer without a chemical filter

[0160] V.trans measurement curve of relative target gas concentration over time for an analyzer with a flow-through filter

Claims

1. An analyzer (100) for analyzing a gas sample (Gp) for at least one target gas to be detected, in, The analyzer (100) comprises - sensor (50,51), - a measuring chamber (30), - a filter element (20) having a chemical filter (22) and at least one filter opening as well as - another component (2, 5, 21) having at least one component opening Wherein, the measuring chamber (30) is designed to receive the gas sample (Gp), wherein the sensor (50, 51) is designed to generate a signal related to the concentration of the target gas in the gas sample (Gp), wherein not only the filter component (20) but also the further component (2, 5, 21) has at least one opening The outside is impermeable to gases. wherein a gap (Sp.i) is created between the filter element (20) and the further element (2, 5, 21), the chemical filter (22) being adjacent to the gap, wherein the filter component (20) and the other component (2,5,21) - jointly surround the measuring chamber (30), and - designed together as a dimensionally stable component, wherein the at least one filter opening and the at least one member opening is arranged such that a gas sample (Gp) is forced onto a path through the gap (Sp.i) and past the chemical filter (22) before the gas sample (Gp) reaches the interior of the measurement chamber (30), wherein the path includes a segment at least 0.5 cm long, and The chemical filter (22) is designed to combine and / or decompose and / or chemically convert at least one substance present or possibly present in the gas sample (Gp) while the gas sample (Gp) flows through the gap (Sp.i) and passes through the chemical filter (22).

2. The analyzer (100) according to claim 1, It is characterized by The path includes segments that are at least 2 cm long.

3. The analyzer (100) according to claim 2, It is characterized by The path includes segments at least 5 cm long.

4. The analyzer (100) according to claim 3, It is characterized by The path includes segments at least 10 cm long.

5. The analyzer (100) according to claim 1, It is characterized by The filter component (20) and the further component (2, 5, 21) each themselves surround the measuring chamber (30).

6. The analyzer (100) according to claim 1, It is characterized by The filter component (20) and the further component (2, 5, 21) are each themselves designed as dimensionally stable components.

7. The analyzer (100) according to any one of claims 1 to 6, It is characterized by The further component (2, 5, 21) surrounds the filter component (20).

8. The analyzer (100) according to claim 7, It is characterized by The further component (2, 5, 21) completely surrounds the filter component (20).

9. The analyzer (100) according to any one of the preceding claims, It is characterized by The filter component (20) and the further component (2, 5, 21) together form a dimensionally stable module.

10. The analyzer (100) according to any one of the preceding claims, It is characterized by The filter element (20) comprises two end surfaces (20.S1, 20.S2) spaced apart from each other and a peripheral surface (20.M). wherein the peripheral surface (20.M) extends between the two end surfaces (20.S1, 20.S2), Wherein, in a first alternative, the or at least one filter opening is embedded in the peripheral surface (20.M), and wherein, in a second alternative, the or at least one filter opening Embedded in the end faces (20.S1, 20.S2).

11. The analyzer (100) according to claim 10, It is characterized by filter opening Embedded accordingly in the two end faces ( 20 . S1 , 20 . S2 ).

12. The analyzer (100) according to any one of the preceding claims, It is characterized by The analyzer (100) comprises a measuring chamber housing (1) and a heatable element (3), Wherein, the measuring chamber housing (1) surrounds - said measuring chamber (30), - said filter member (20), and - said other member (2, 5, 21), Wherein, the heatable element (3) - is in thermal contact with said measuring chamber (30), and - designed to heat the interior of the measuring chamber (30), The lower opening (8) and the upper opening (7) are embedded in the measuring chamber housing (1). Wherein, the lower opening (8) is arranged vertically or obliquely below the upper opening (7).

13. The analyzer (100) according to claim 12, It is characterized by The sensor comprises a radiation source (10) and a detector member (11), and The analyzer (100) comprises a mirror (5), wherein the radiation source (10) is designed to emit electromagnetic radiation (eS), Wherein, the analyzer (100) is designed so that - the emitted radiation (eS) penetrates the measuring chamber (30) at least once, - impacts onto the detector member (11), and - is reflected at least once by the mirror (5) on the way from the radiation source (10) to the detector member (11), and The heatable component (3) additionally holds the mirror (5).

14. The analyzer (100) according to claim 12 or claim 13, It is characterized by The sensor (50, 51) includes a detector (31) and a detection parameter sensor (34, 35), The detector (31) is designed to oxidize the combustible target gas in the measuring chamber (30). The detection parameter sensors (34, 35) are designed to measure the amount of heat energy released when oxidizing the combustible target gas, and The detector (31) also serves as the heatable element (3).

15. The analyzer (100) according to any one of the preceding claims, It is characterized by The analyzer (100) comprises a measuring chamber housing (1) and a detector housing (2). Wherein, the measuring chamber housing (1) surrounds - said measuring chamber (30), - said filter member (20) and - said other member (2, 5, 21), and The measuring chamber housing (1) is or can be connected to the detector housing (2) in a releasable manner.

16. The analyzer (100) according to claim 15, It is characterized by The sensor (50, 51) comprises a radiation source (10) and a detector member (11), wherein the radiation source (10) is designed to emit electromagnetic radiation (eS), wherein the analyzer (100) is designed such that the emitted radiation (eS) penetrates the measuring chamber (30) at least once and impinges on the detector element (11), wherein the detector member (11) is designed to generate a signal related to the concentration of the target gas in the gas sample (Gp) based on the intensity of the impinging electromagnetic radiation (eS), and The detector housing (2) surrounds the radiation source (10) and the detector component (11).

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