Sensor unit, gas warning device, gas warning system, method for performing a maintenance procedure on the gas warning device and method for performing a gas measurement with the gas warning device

Abstract

Sensor unit (3), designed for arrangement in a gas warning device (100), which has a gas sensor (60), characterized by the fact that the sensor unit (3) comprises a circular cylindrical receiving device (10) and a cover (20) which has a cover plate (20'), wherein the gas sensor (60) and at least one control and data processing unit (50) which is in communicative connection with the gas sensor (60) are arranged in the circular cylindrical receiving device (10), and - the cover plate (20') has a test gas access (21) through which a fluid path (a) for a test gas is provided to the gas sensor (60), and wherein the circular cylindrical receiving device (10) provides a fluid path (b) for a measuring gas to the gas sensor (60), wherein the sensor unit (3) has an electronic interface (111) located on the circular cylindrical receiving device (10), which is designed to be communicatively connected to a corresponding electronic interface in a user arrangement.

Description

[0001] The invention relates to a sensor unit, a gas warning device, a gas warning apparatus, a method for performing a maintenance operation on the gas warning device and a method for performing a gas measurement with the gas warning device.

[0002] Gas detectors are known from the prior art that emit a warning signal when one or more gases are present or when a limit value is exceeded. Such gas detectors are used to protect people from poisoning or suffocation, or for fire and explosion protection in buildings and facilities, to warn personnel of the danger associated with the presence of the gas. These devices can be worn on the body, but are more commonly installed on walls or ceilings to monitor the ambient air.

[0003] To ensure the highest possible safety and reliability of the devices, it is necessary to regularly check the functionality of the sensors or replace them. For the functional test, a test gas must be supplied to the sensors. This gas is prevented from escaping rapidly from the sensor's immediate measuring environment by a dipping cap, thus triggering a warning signal if the sensor is functioning correctly. Replacing the sensors requires opening the housing, removing the sensors, and wiring the replaced sensors to the housing's electronics. The sensors then need to be recalibrated before the device can be used again. To expedite maintenance or replacement, the entire device is often replaced.

[0004] DE 103 29 834 A1 describes a gas warning device comprising a gas detector as a base unit with electrical supply and data lines for communication with a central control unit. The base unit is connected via quick-release fasteners to a measuring unit, which includes a sensor and a microprocessor for evaluating and processing the measurement signal.

[0005] Furthermore, WO 2008 / 121 564 A1 discloses a gas warning device consisting of a two-part housing, comprising a base and a lid. A gas sensor is mounted on a circuit board permanently installed in the base. The device is designed to allow for improved testing of the gas sensor. For this purpose, a flat coupling component is placed between the base and lid. During testing, this component rests on the gas sensor and seals it off via a sealable recess, except for a test gas inlet that connects a test gas reservoir via a hose. This allows the gas sensor to be directly flooded with gas.

[0006] DE 297 23 859 U1 discloses a CO2 sensor device comprising a dome-shaped protective cover that encloses a gas sensor. The gas sensor is positioned on a carrier plate connected to a base plate. The dome-shaped protective cover is attached to the carrier plate by means of pillars.

[0007] JP 2014 - 74 645 A further describes a gas detector whose housing can be closed with a circular lid that is screwed onto the housing. A circuit board with an attached sensor is placed on top of the housing and enclosed by a cuboid housing into which the gas sensor is inserted.

[0008] Finally, TW 000 00M 589 766 U reveals a gas detector, similar to a fire alarm. A multi-part, circular cylindrical housing encloses a gas sensor mounted on a circuit board.

[0009] Based on this state of the art, the object of the present invention is to provide a sensor unit that can be maintained in an optimized manner with regard to assembly and time expenditure.

[0010] This problem is solved by a sensor unit having the features of claim 1.

[0011] Furthermore, the task of providing a gas warning device that can be easily and quickly maintained is solved by a gas warning device with the features according to claim 3.

[0012] The task of providing a gas warning device whose maintenance is optimized in terms of time and assembly is solved by the gas warning device with the features of claim 16.

[0013] Furthermore, the task arises to provide an improved procedure for maintaining gas warning devices.

[0014] This problem is solved by the method for performing a maintenance operation with the features of independent claim 17.

[0015] Furthermore, the additional problem of carrying out a simplified and reliable gas measurement is solved by the method for carrying out a gas measurement with the features of claim 18.

[0016] Further developments and preferred embodiments of the sensor unit, the gas warning device and the gas warning apparatus, as well as the methods for maintenance and gas measurement with the gas warning device, are described in the dependent claims.

[0017] According to a first embodiment of the sensor unit according to the invention, it is designed for installation in a gas warning device and includes a gas sensor. The sensor unit comprises a circular cylindrical receiving device and a cover plate, wherein the gas sensor and one or more control and data processing units are arranged in the circular cylindrical receiving device. Each control and data processing unit is in communicative contact with the gas sensor. The cover plate further includes a test gas inlet through which a fluid path for the test gas to the gas sensor is provided. The circular cylindrical receiving device provides another fluid path for a measuring gas to the gas sensor.According to the invention, the sensor unit has an electronic interface located on the circular cylindrical receiving device, which is designed to be communicatively connected to a corresponding electronic interface in a usage arrangement.

[0018] The control and data processing unit of the sensor unit is advantageously designed to initiate, read, and evaluate gas measurements using the gas sensor. All data processing can therefore take place within the sensor unit, allowing it to forward processed data to a central data processing unit, for example. No raw data needs to be sent or evaluated elsewhere. Communication with the central unit thus refers to any type of electronic data transmission.

[0019] In this context, "electronic interface" refers to any type of connection between two corresponding data-transmitting electrical lines. Electronic interfaces can be any type of connector, such as USB connectors, or other data transmission connectors deemed suitable by an expert. Wireless or contactless data transmission is also possible.

[0020] In this context, a "usage arrangement" means that the sensor unit is electrically and electronically connected to other electronic components, so that it is ready to perform a gas measurement or a test measurement.

[0021] According to a further embodiment of the sensor unit according to the invention, the circular cylindrical receiving device includes a measuring tube that provides a measuring section for the gas in the fluid path leading to the gas sensor. In this embodiment, the gas sensor is an optical gas sensor, and a suitable light or radiation source for illuminating the measuring section and an electrical connection to the control and data processing unit are also provided. The light source emits thermal radiation in the infrared or ultraviolet range, which is suitable for detecting, for example, CO2. Various sensors can be integrated into the sensor unit, such as semiconductor, electrochemical, photoacoustic, and other types of sensors.

[0022] A gas warning device comprising a sensor unit according to the invention has a housing with a housing cover, a housing body, and a housing base. The housing cover has a recess with a base in which an electronic interface is located.

[0023] The recess has primary locking means, and the sensor unit has secondary locking means that can be releasably engaged with the primary locking means. The housing and the circular cylindrical receiving device of the sensor unit provide a fluid path for the measuring gas to the gas sensor, as an inlet gap for the gas is formed between the housing and the receiving device.

[0024] The electronic interface of the base is communicatively connected to the electronic interface of the circular cylindrical mounting device in an operating arrangement where the sensor unit is detachably mounted in the recess of the housing; thus, signal transmission takes place. Among other things, values ​​from the sensor unit or simple control commands can be transmitted. The interface also serves to supply power to the sensor unit. The electronic interface of the mounting device is, in turn, communicatively connected to the electronic interface of the control and data processing unit.

[0025] This arrangement of a sensor unit within the housing forms a gas warning device according to the invention.

[0026] Advantageously, the sensor unit can be replaced easily and quickly, as it is detachably arranged in the housing of the gas detector by unlocking the two interconnected locking mechanisms.

[0027] Thanks to electronic interfaces, preferably designed as plug-in systems or even contactless, the gas sensor can be easily connected electronically to other components that may be located in the housing. This allows for tool-free replacement of the sensor unit and other components. An electronic connection can thus be established between the sensor unit's control and data processing unit and the central unit. The sensor unit is simply plugged in and locked into place using the locking elements in the recess.

[0028] Embedding the sensor in a sensor unit with complete data processing electronics allows the user to quickly and easily connect the sensor to the housing or replace the entire unit. The sensor unit thus forms a separate, interchangeable component.

[0029] The term "operating arrangement" herein means that the sensor unit is inserted into the housing and electrically and electronically connected to other electronic components so that a gas measurement or a test measurement can be carried out.

[0030] The term "fluid path for a measuring gas" refers here to a continuous flow path through which the measuring gas can flow unimpeded, a path that is labyrinthine due to the geometry of the components. This labyrinthine design of the fluid path advantageously provides splash protection for the sensor, as external splash water or moisture cannot reach it, since the sensor is protected within the sensor unit and not exposed. When the sensor unit is mounted in the recess of the housing, a gap exists between the two components.

[0031] In a preferred embodiment, the circular cylindrical receiving device has a ring element with a base section containing a recess through which the fluid path for the measuring gas passes. The recess is designed to provide a passage for the electronic interface of the base of the housing cover for connection to the electronic interface of the sensor unit. Furthermore, the circular cylindrical receiving device has a circular cylindrical base plate with several retaining elements, such as retaining clips, around its circumference. These retaining elements serve to hold or position the sensor unit within the housing recess. The circular cylindrical base plate also has a recess that provides a passage for the electronic interface of the base of the housing cover for connection to the electronic interface.There are several openings in the base plate designed to allow the sample gas to pass through – these are part of the fluid path. To form the circular cylindrical receiving device, the ring element sits on the circular cylindrical base plate, preferably on a thickened circumferential edge (on the outer side of which the retaining elements are located). The openings can be distributed around the circumference of the base plate or located in the center. This allows the sample gas to flow advantageously and uniformly into the sensor unit.

[0032] In a further embodiment of the gas warning device according to the invention, the ring element has an outer flange at its edge facing the base section. "Flange" here generally refers to a projection circumferentially around the ring, serving as an element for positioning, sealing, connecting, or closing the receiving device with the cover. The cover has a circular cylindrical shell that supports the cover plate and is abutted against the flange. Preferably, the shell rests on a sealing element located on the flange, particularly preferably on a sealing ring. The shell acts as a flow aid for the measuring gas approaching from the outside and also has locking elements that can be engaged with corresponding retaining elements, such as the retaining clips on the base plate.

[0033] In yet another embodiment of the gas warning device according to the invention, a rotating ring is arranged circumferentially around the outer surface of the sensor unit's cover. It can be rotated in the operating configuration. To protect the rotating ring from splashing water, the cover plate preferably extends over the rotating ring, and in the operating configuration, it rests against an edge of the recess in the housing. It preferably rests rotatably on the edge by means of an outer circumferential grip of the rotating ring to create a further turn in the measuring gas fluid path. The rotating ring has two or more types of positioning elements, preferably three types, which, in conjunction with positioning elements on the housing, determine the position of the rotating ring in the recess.The positioning elements make it possible to move and hold the rotating ring in different positions and to make the measuring gas fluid path open or closed.

[0034] According to a further embodiment of the gas warning device according to the invention, the positioning elements of all types are first plates, second plates, and third plates, which extend from an underside of the rotating ring facing the circular cylindrical base plate towards the circular cylindrical base plate. The first plates are arranged radially closer to a center point of the rotating ring on the underside of the rotating ring than the second plates, preferably on an inner circumference of the rotating ring. They are spaced apart from each other by gaps, as are the second plates. These are also located on the underside of the rotating ring, preferably on its outer circumference. The gaps between the first plates and the gaps between the second plates are not congruent.

[0035] Particularly preferred with regard to the axial extent of the plates are that the second plates are shorter than the first plates in order to form a further section of the labyrinthine fluid path together with other components located at the recess. The plates are thus arranged on two circular rings with different radii. The plates are distributed around the circumference of these two circular rings and are equidistant from each other. The plates arranged along the circular rings are offset from one another in order to form the fluid path for the measuring gas, or to ensure its continuous flow, in conjunction with the positioning elements of the housing.

[0036] In a further embodiment of the gas warning device according to the invention, the third plates extend from an underside of the rotating ring facing the circular cylindrical base plate towards the circular cylindrical base plate. The third plates are arranged radially to a center point of the rotating ring between the first and second plates and are spaced apart from each other by gaps on the underside of the rotating ring. The gaps between the first plates and the gaps between the second plates are preferably not congruent with the third plates, so that the fluid path can be opened or closed depending on the setting of the rotating ring.

[0037] With regard to the axial extent of the plates, the third plates are shorter than the first plates to allow rotation of the rotating ring without the different components of the rotating ring and the recess in the housing cover interfering with each other during rotation. The third plates are also arranged along a circular ring and are equidistant from each other.

[0038] All three plate types are arranged radially offset from one another, so that depending on the position of the rotating ring, the fluid path for the measuring gas can be made either open or closed. The distance between the imaginary circular rings creates a kind of annular groove that corresponds to the width of the edge of the housing recess, allowing the edge to be received in this groove and thus forming a loop around it. This loop forms a coil in the measuring gas fluid path, allowing the measuring gas to be guided into the recess and onward into the sensor unit.

[0039] Furthermore, in yet another embodiment of the gas warning device according to the invention, the positioning elements, which are located on the outer circumference of the edge of the recess, are spaced apart from one another by gaps. The edge of the recess forms a circular ring on which the positioning elements are preferably arranged equidistant from one another. The positioning elements simultaneously serve as detents and fluid guides, so that the rotating ring can assume various positions along the circumference of the edge of the recess. The positioning elements thereby act as travel limiters, which preferably restrict the movement of the rotating ring to two positions: open or closed.

[0040] In yet another embodiment of the gas warning device according to the invention, retaining ribs are distributed on the base along an inner surface of the housing recess. These ribs extend longitudinally with respect to the surface, which engages with the retaining elements of the circular cylindrical base plate to releasably hold the sensor unit in the recess. The retaining elements are preferably retaining brackets whose shape corresponds to the shape of the retaining ribs. The brackets and the retaining ribs are congruent in their position and shape and together form a groove and rail, allowing the retaining brackets to be slid over the retaining ribs, thus creating a rotationally secure hold for the sensor unit in the housing recess.

[0041] According to yet another embodiment of the gas warning device according to the invention, a circular rib is located on the base of the housing in the housing cover, positioned at a distance from the inner surface of the recess. Furthermore, the circular cylindrical base plate of the sensor unit has a groove circumferentially on its base-facing side, allowing the gas to reach at least some of the openings in the circular cylindrical base plate. The groove can accommodate the circular rib of the base of the housing recess, with a gap remaining between the groove and the rib. The rib is positioned circumferentially on the base, close to the surface of the recess. This, along with the gap between the groove and the rib, forms another section of the labyrinthine fluid path for the measuring gas.

[0042] Should splash water nevertheless penetrate the recess, which can occur in very humid environments, another embodiment provides that the recess has outlet openings or a drainage channel at a suitable location, in which any penetrating liquid can collect and flow out of the recess and away from the electronic components of the sensor unit or housing. Furthermore, in one operating arrangement, the recess is oriented relative to the floor of a room so that it extends parallel to it. If the recess in the housing is designed with an incline, any water that penetrates the operating arrangement can then easily drain away.

[0043] According to a further embodiment of the gas warning device according to the invention, the first locking means can be elements located in the recess on an inner surface of the casing and pointing radially inwards, such as projections or lugs.

[0044] The second locking means of the sensor unit are located on two or more positioning elements (second plates) of the rotating ring and can be designed as longitudinal ribs on the outer surface of the second plates. When engaged, these ribs engage under the projections or lugs, forming a rail-like connection. "Rail-like" means that both the lugs and the longitudinal ribs extend parallel to each other and abut each other when the sensor unit is inserted into the recess. This secures the sensor unit in the housing and allows the rotating ring to be operated without the sensor unit rotating within the housing recess.

[0045] The locking elements further ensure that the sensor unit can only be inserted into the recess in a preferred, predetermined position. This is also achieved by the projection guided within the recess, which allows for unambiguous positioning of the circularly symmetrical components. The connection of the electrical interfaces, i.e., the insertion of the plug connector, can thus be carried out simply and securely, and the electrical interfaces are protected from damage by this guide.

[0046] According to a further embodiment of the gas warning device according to the invention, the rotating ring of the sensor unit can be arranged in various positions relative to the recess: The rotating ring can be brought into an open position, in which the fluid path of the measuring gas is continuous from outside the gas warning device to the gas sensor. In this open position, the positioning elements at the edge of the recess and the positioning elements of the rotating ring are aligned with each other; that is, the positioning elements of the rotating ring, here the second plates, cover the positioning elements of the edge when the fluid path of the measuring gas is followed. The corresponding gaps between the positioning elements of the rotating ring are then located at the same position as the positioning elements of the edge of the recess, so that measuring gas can enter the gap between the recess and the sensor unit.

[0047] Furthermore, the rotating ring can be moved or turned into a closed position in which the fluid path for the measuring gas from outside the sensor unit to the gas sensor is blocked. In this position, the positioning elements of the recess's edge and the positioning elements of the rotating ring, for example, the second plates, are offset from each other by their circumference relative to the recess's edge. Conversely to the open position, in this rotating ring position, the gaps of the rotating ring's positioning elements are not located at the same position as the gaps of the positioning elements on the recess's edge. Thus, the measuring gas cannot enter the gap between the recess and the sensor unit and cannot be directed to the sensor.

[0048] Preferably, the rotary ring can assume two positions—open and closed—due to the specific arrangement of the positioning and locking elements of the rotary ring and the housing recess relative to each other. Rotation in either direction is limited by this arrangement of positioning and locking elements.

[0049] To facilitate easy replacement of the sensor unit, the rotating ring can be moved or turned into an exchange position in which the first locking elements are not engaged with or released from the second locking elements. The locking elements can be released via release elements, which are ergonomically designed for easy access and operation, allowing the sensor unit to be removed from the recess with one hand and without tools. The locking elements are spring-loaded and incorporate a ball element, ensuring easy engagement during installation and easy release when the sensor unit needs to be replaced.

[0050] According to one embodiment of the gas warning device according to the invention, the rotating ring has one or more handles, one of which is located on an outer circumference of the rotating ring. The handle allows the rotating ring to be adjusted to the described positions, which a user can easily do with one hand. The position of the handle also indicates to the operator the position of the rotating ring. This can also be indicated on the housing, for example, by pictograms embedded in or affixed to the housing material, so that in this display example, the operating mode of the sensor unit is immediately and clearly apparent by rotating the rotating ring and adjusting the handle to the position corresponding to a pictogram.

[0051] In yet another embodiment of the gas warning device according to the invention, a battery is arranged in the circular cylindrical receiving device, which can operate a clock located in the sensor unit and which measures the time period during which the sensor unit is in operation.

[0052] Furthermore, the gas warning device according to the invention can have an output device, such as an optical or acoustic output device, which, according to one embodiment, can be located in the sensor unit or on the housing and is communicatively connected to the control and data processing unit of the sensor unit. The output device can output states of the sensor unit (current / warning state) or measured values ​​of the gas sensor or position data acquired by position sensors located on the housing and designed to detect the respective position of the rotating ring, and which are communicatively connected to the control unit, to a user by emitting a tone, tones, noises or audio sequences, or by illuminating a warning light, which is located, for example, in the cover of the sensor unit or other parts of the housing.

[0053] If a light is present, a color code, for example, can indicate whether a warning situation exists (high readings), whether the sensor unit needs maintenance due to a routine test, or even whether the entire sensor unit needs to be replaced due to a faulty sensor.

[0054] According to a further embodiment of the gas warning device according to the invention, the housing has an electronic input button, e.g. a capacitive button. The button can, for example, serve to acknowledge a state of the sensor unit output by the output device, or to make inputs.

[0055] According to a preferred embodiment of the gas warning device according to the invention, position sensors for detecting the different positions of the rotating ring are arranged in the sensor unit or the housing. The position sensors are communicatively connected to the control and data processing unit for transmitting the detected positions. Preferably, the position sensors are reed contacts, but other simple position or contact sensors can also be used. The control unit activates an operating configuration of the sensor unit when the rotating ring is detected in an open position. If a closed position of the rotating ring is detected, the control unit activates a test configuration of the sensor unit.When a replacement position is detected, the gas warning device can also be put into a corresponding replacement configuration, so that when a new sensor unit is inserted, it is immediately detected and controlled in order to teach it in.

[0056] Furthermore, in another embodiment of the gas warning device according to the invention, the control and data processing unit on the sensor unit can be composed of several parts. The sensor unit includes a sensor circuit board with electronics for controlling and reading the sensor, a circuit board with electronics for the optical and acoustic output device, and optionally a separate circuit board with communication electronics that can communicate with further electronics in the rest of the housing. Advantageously, all data processing of the measurement data is carried out by the electronic components within the sensor unit. A further circuit board with communication electronics for connecting the sensor unit to a corresponding peripheral, such as the central processing unit, is arranged in the housing.

[0057] Furthermore, the gas warning device according to the invention can be part of a device network. For this purpose, the gas warning device has suitable communication electronics known to those skilled in the art. The measured data can be temporarily stored on the gas warning device; for this purpose, the gas warning device has a corresponding storage unit; or the data can be forwarded directly to the network or a predetermined network node or the central unit, either wired or wirelessly, for further data processing.

[0058] According to a further embodiment of the gas warning device according to the invention, the housing has a protective cover arranged above the housing lid, covering the area above the recess, thus protecting an inserted sensor unit from further damage, such as impacts. The protective cover can be constructed of struts or plates that arch over the entire housing lid and has openings. The protective cover forms a bridge, providing sufficient lateral space to allow access to the rotating ring.

[0059] A gas warning device comprises one or more gas warning devices according to the invention and a central data processing unit. Each gas warning device can be communicatively connected to the central unit. The gas warning device according to the invention thus forms a measurement network from a plurality of gas warning devices that can be connected to the central unit as the central data processing unit, in order to carry out effective gas measurement within several rooms or an entire building. Furthermore, a gas warning device can also be formed by connecting the sensor unit, e.g., a PC as the central unit.

[0060] A method according to the invention for performing a maintenance operation on the gas warning device according to the invention comprises the following steps: - Separating the first locking means, which has the recess, and the second locking means, which has the sensor unit, and which can be detachably engaged with each other, - Removing the sensor unit with the gas sensor from the recess in the housing, and - Inserting a new sensor unit with a new gas sensor into the recess of the housing, - engage the first locking means which has the recess and the second locking means which has the sensor unit and which can be detachably brought into engagement with each other.

[0061] This design offers the advantage of quick and easy sensor replacement, as the entire sensor unit can simply be removed from the housing or a new sensor unit inserted. Unlike previous technologies, this eliminates the need to individually connect the sensor or its terminals electrically, perform complex programming, or replace the entire gas detector. Integrating the sensor into a sensor unit with the necessary electronics allows the user to install the sensor with precise positioning and accuracy, resulting in less drift in the readings compared to a separately programmed and installed sensor.

[0062] In a further embodiment, the maintenance method according to the invention comprises first checking the position of the rotating ring, whereby the position of the rotating ring must be changed to the exchange position by simply rotating the rotating ring, depending on its condition. The locking elements are then released so that the sensor unit can be removed. To then secure the newly inserted sensor unit, the rotating ring is first turned from the exchange position to the closed position for a test measurement and, when regular measurement operation is to commence, to the open position. As soon as the rotating ring is turned out of the exchange position, the sensor unit is firmly and securely received and held in the recess of the housing and electrically connected to the other electronic components located in the housing.

[0063] An inventive method for performing a gas measurement with the inventive gas warning device enables a gas measurement that is either a test of the gas sensor with a test gas or a measurement with a sample gas. The method has two phases, wherein in a first phase, which corresponds to a test phase, the following steps are carried out: - Bringing the rotating ring into a closed position in the recess, wherein in the closed position the measuring gas fluid path from outside the sensor unit to the gas sensor is not continuous, wherein the positioning elements of the edge of the recess and the positioning elements of the rotating ring are positioned circumferentially offset from each other in relation to the edge of the recess, - Supplying a test gas through the test gas access point under the cover plate, through which the fluid path for the test gas to the gas sensor is provided, to the gas sensor, wherein the test gas access point is located in the cover plate of the sensor unit, - Detecting the test gas with the gas sensor and generating a measurement signal, - Output of a measured value correlated with the measurement signal by the control and data processing unit.

[0064] Because the test gas fluid path is closed during this test measurement, only the test gas fluid path remains open. This is advantageous because the test gas, introduced separately via the test gas inlet directly into the gas sensor's measuring area, cannot immediately escape but can remain there. An additional immersion cap, which is placed over the sensor unit or the entire gas detector to prevent test gas from escaping the measuring chamber around the gas sensor, is no longer necessary. This improves the gas sensor's response time, requiring only a small amount of test gas. When not in use, the test gas inlet can be closed, for example, with a rubber stopper that can be securely attached to the cover plate.

[0065] In a second phase, which corresponds to a measurement phase in regular operation, the following steps are carried out: - Bringing the rotating ring into an open position in the recess, wherein in the open position the measuring gas fluid path from outside the gas warning device to the gas sensor is continuous, and the positioning elements of the edge of the recess and the positioning elements of the rotating ring are partially aligned with each other, wherein the positioning elements of the rotating ring partially or completely obscure the positioning elements of the edge of the recess, - Flowing a sample gas along the sample gas fluid path to the gas sensor, - Detecting the gas with the gas sensor and generating a measurement signal, - Output of a measured value correlated with the measurement signal by the control and data processing unit.

[0066] The first and second phases can of course also be carried out in reverse order or at a time interval.

[0067] The measured values ​​output by the control and data processing unit can be further processed by the data processing unit itself or transferred to a device network via the second communication unit located in the housing, where the measured values ​​are then further processed, for example, on a suitable network node or the central unit.

[0068] Advantageously, rotating the rotary ring opens or closes the fluid path for the sample gas, allowing the user to directly see the current configuration of the sensor unit and easily change or adjust it. This makes setting a specific operating configuration, whether for measurement or testing, simple and unambiguous.

[0069] In a preferred embodiment of the inventive method, the measuring gas fluid path runs from outside the sensor unit along the overlapping gaps between the second plates and the gaps of the positioning elements at the edge of the recess, and further along the overlapping gaps of the third plates and the gaps of the first plates, and further along the outer surface of the recess over the web through the openings in the base plate of the sensor unit to the gas sensor. This causes the measuring gas to flow along a labyrinthine path, which on the one hand provides protection against splashing water and on the other hand allows the measuring gas to flow uniformly around the sensor within the sensor unit.

[0070] Further embodiments of the gas warning device and the sensor unit, as well as some of the advantages associated with these and other embodiments, will become clearer and more easily understood through the following detailed description with reference to the accompanying figures. Items or parts thereof that are essentially the same or similar may be provided with the same reference numerals. The figures are merely a schematic representation of one embodiment of the invention.

[0071] This shows: Fig. 1 an exploded view of a gas warning device according to the invention, Fig. 2 an exploded view of a gas warning device according to the invention with gas warning unit with open housing cover and schematic connection to a central unit, Fig. 3 an exploded view of the sensor unit of the gas warning device according to the invention, Fig. 4 a perspective view of the sensor unit and the corresponding recess in the housing, Fig. 5 A first cross-sectional view through the gas warning device with the rotating ring open, Fig. 6 a second partial sectional view through the gas warning device with open rotating ring and marked measuring gas fluid path b, Fig. 7 Another partial sectional view through the gas detector with the rotating ring closed, Fig. 8 Another sectional view through the gas warning device with the rotating ring closed and the test gas fluid path a drawn in, Fig. 9 a perspective view of the rotating ring in combination with the recess in the case in a closed position, Fig. 10 a perspective view of the rotating ring in combination with the recess in the housing in an exchange position, Fig. 11 a) a top view, b) a side view and c) a sectional view along BB of the rotating ring in the closed position, Fig. 12 a) a top view, b) a side view and c) a sectional view along AA of the rotating ring in the open position, Fig. 13 an exploded view of another embodiment of the gas warning device, Fig. 14 an exploded view of a further embodiment of the gas warning device, and Fig. 15 a sectional view through a further embodiment of the gas warning device with an open rotating ring.

[0072] In Fig. 1 and Fig. Figure 2 shows a gas detector 1 comprising a protective cover 2, a sensor unit 3, and a housing 7, the housing 7 being mounted on a mounting plate 8 which has openings 8' for this purpose. The mounting plate 8 serves to mount the housing 7 of the gas detector 1, for example, on a wall, and has the necessary mounting openings 8" for this purpose.

[0073] The housing 7 has a housing cover 4 with a recess 3' in which the sensor unit 3 can be accommodated and which is geometrically corresponding to the sensor unit 3.

[0074] The housing cover 4 is hinged to a housing body 5 via hinges 5', the housing body 5 resting on a housing base 6. The housing base 6 is screwed to the mounting plate 8 in a mounting arrangement, as shown in particular Fig. Figure 2 shows. The housing body 5 accommodates in a recess 5" a housing 9' with communication electronics 9, which includes, among other things, a network interface for a wireless or wired connection 81 with a central unit 80 (in Fig. 2 (both shown with dashed lines). Together with the central unit 80, the gas detector 1 forms a gas warning device 100.

[0075] The protective cover 2 has a plurality of parallel curved struts 2' which bridge the underlying sensor unit 3 and provide protection against damage. Between the struts 2' are openings 2", which space the struts 2' apart.

[0076] The sensor unit 3 and its insertion into the housing cover 4 of the housing 7 are described in detail in Fig. 3 and Fig. 4 shown as well as in sectional views in Fig. 5 to 8, wherein the sensor unit 3 comprises as essential components a circular cylindrical receiving device 10, a sensor board 50 with an attached gas sensor 60, and a cover 20. The gas sensor 60 has a measuring tube 61 in a measuring tube housing 60', the measuring tube 61 being arranged in a measuring tube holder 63 and fastened in the receiving device 10 by means of a screw connection 62. The measuring tube housing 60' contains the measuring tube 61 and holds the sensor board 50 on one of its outer sides, as well as a light source 64 on the side facing away from the sensor board 50, which can illuminate the measuring section, the length of which is determined by the dimension of the measuring tube 61. The sensor board 50 has suitable detection means for the light emitted by the light source 64 in the IR or UV range, which is suitable for the detection of CO2.

[0077] The receiving device 10 has a circular base plate 70, which has four retaining brackets 71 around its outer circumference as holding means ( Fig. 3) has. Furthermore, a recess 70' is provided in the base plate 70, which forms a passage for an electronic interface 11, which is located in the recess 3' on the bottom 3" of the housing cover 4 of the housing 7, as shown in Fig. 4 and Fig. Figure 5 shows that the base plate 70 has a plurality of openings 74 along its circumference and in the center, allowing a measuring gas to pass through. A thickened rim 70" of the base plate 70 forms a border for the openings 74 and has a projection 72 that serves as an orientation aid when the sensor unit 3 is to be inserted into the recess 3' in the housing cover 4.

[0078] The receiving device 10 further comprises a ring element 65 with a base section 165 in which a recess 165' is provided, which is fluidically connected to the through-openings 74 of the base plate 70. The ring element 65 has an outer flange 65', which is located on the edge of the ring element 65 facing the base section 165. A groove or sealant receptacle 68 is formed in the flange 65', into which a sealant can be inserted. The ring element 65 further comprises on its side facing away from the base section 165 (in Fig. 3) Slots 66 are located at the upper edge, serving to attach another circuit board, the processor board 40, which rests on the upper edge. The processor board 40 has corresponding slots 42 into which suitable fastening elements can engage. The ring element 65 serves as a frame for the gas sensor 60. The screw connection 62 of the measuring tube holder 63 is attached to the bottom section 165 of the ring element 65. The processor board 40 carries a loudspeaker 41, which is connected to a cone 25 of the cover 20 (see figure) via an annular seal 44. Fig. 8) seals from the inside.

[0079] Various electronic components are arranged on the sensor board 50, serving to control the gas sensor 60, acquire measurement data, and process that data. The electronics of the sensor board 50 form the control and data processing unit of the sensor unit 3 and enable complete data evaluation on the sensor unit. The processor board 40 can carry further electronic components necessary for data processing. For example, a battery 17 is attached to the processor board 40, which powers a clock with a calendar that measures how long the sensor unit 3 is active.

[0080] The sensor board 50 further carries an electronic interface 111 facing the receiving element 10 and an electronic interface 511 facing the processor board 40. The processor board 40 has an electronic interface 411 that corresponds to the electronic interface 511 of the sensor board 50. It has a U-shaped cutout 43 at its edge. The aforementioned electronic interfaces 111, 511, 411 are electrically and electronically connected in the operating arrangement, wherein the electronic interface 111 facing the receiving element 10 corresponds to and is electrically and electronically connected to the electronic interface 11, which passes through the recess 70' in the base plate 70, as shown in Fig. 5 and Fig. 7 is shown.

[0081] The electronic interfaces listed in total, 511, 411, 111 and 11, are, as Fig. Figures 3 to 7 illustrate an operating arrangement of the gas warning device 1 in direct electrical contact, where the sensor unit 3 and housing 7 are mechanically connected. This provides the electrical and electronic contact between the electronics for the gas sensor 60, which is connected to the sensor board 50, and the electronics for communication with the central unit 80, which is located in the housing 7.

[0082] The ring element 65 has a channel 67 for the test gas access and rail elements 69 that provide a guide for the sensor board 50 and hold it securely in position in an operating arrangement.

[0083] The cover 20 is mushroom-shaped and has a cover plate 20' and an insert 22. The cover 20 also has a circular cylindrical shell 23, which is supported against the flange 65' and carries the cover plate 20'. The circular cylindrical shell 23 has four locking recesses 24, evenly spaced around its circumference, which engage with the retaining clips 71.

[0084] The cover plate 20' also has a test gas inlet 21, through which test gas can be directed to the gas sensor 60 via a fluid path a. As in Fig. As can be seen in Figure 8, a fluid path a (test gas fluid path) can be traversed by introduced test gas.

[0085] A gap 26 is formed between the circular insert 22 and the cover plate 20', which serves as an exit gap for acoustic signals from the loudspeaker 41. For this purpose, the cover plate 20' also has an inner cone 25 that defines an air space above the loudspeaker 41.

[0086] Below and projecting beyond the cover plate 20', a rotating ring 30 surrounds the shell 23 and is rotatably mounted around the shell 23. The rotating ring 30 is supported by an inner circumferential lower edge, as Fig. Figure 5, which faces the base plate 70, points towards an upper edge 71' of the retaining brackets 71 of the base plate 70. The rotational movement can take place in two, or at most three, positions, whereby the rotational movement of the rotating ring 30 is limited by positioning elements 34 against the side edges 71" of the retaining brackets 71, see Figure 5. Fig. 4.

[0087] The rotary ring 30 has three types of positioning elements, such as the Fig. 3, Fig. 4, Fig. 9, Fig. 10, Fig. Figures 11c) and 12c) show that these positioning elements, in conjunction with positioning elements 15 located at an edge 15' of the recess 3', enable the rotating ring 30 to assume different positions, as explained in more detail below.

[0088] The positioning elements of all types are first plates 34, second plates 33, and third plates 36, which extend from an underside of the rotating ring 30 facing the base plate 70 towards the base plate 70. The plates 33, 34, and 36 lie on imaginary circular rings with different radii. The first plates 34 are arranged radially closer to a center point of the rotating ring 30 on its underside and are located on the inner circumference of the rotating ring 30. They are spaced apart from each other by gaps 34', as shown. Fig. Figures 11c) and 12c) show the second plates 33. The second plates 33 are also located on the underside of the rotating ring 30, but on its outer circumference, and are also spaced apart from each other by gaps 33'. The gaps 34' between the first plates 34 and the gaps 33' between the second plates 33 are not congruent with each other, and with respect to the axial extent of the plates 33, 34, the second plates 33 are shorter than the first plates 34.

[0089] The third plates 36 extend from an underside of the rotating ring 30 facing the base plate 70 towards the base plate 70. With respect to their radial arrangement relative to a center point of the rotating ring 30, i.e., on a circumferential line between the first plates 34 and the second plates 33, the third plates 36 are also located on the underside of the rotating ring 30. The third plates 36 are also spaced apart from one another by gaps 36'. The gaps 34' of the first plates 34 and the gaps 33' of the second plates 33 are not congruent with the gaps 36' of the third plates 36. With respect to their axial extent, the third plates 36 are shorter than the first plates 34 and the same length as the second plates 33.

[0090] The recess 3' in the housing cover 4 of the housing 7 is essentially circular cylindrical, as in Fig. Figure 4 shows a rim 15' projecting over a surface of the housing cover 4, with outwardly pointing positioning elements 15 distributed equidistantly around its circumference, located between gaps 15". The gaps 15" are the same length as the positioning elements 15.

[0091] Furthermore, the recess 3' has a base 3". On the base 3", retaining ribs 12 are arranged distributed along an inner surface of the recess 3' of the housing 7, extending longitudinally axially with respect to the surface of the recess 3'. Inserting the sensor unit 3 into the recess 3' of the housing 7 involves guiding the projection 72 into the groove 13 and inserting the sensor unit 3 perpendicularly into the recess 3'. This ensures secure insertion, preventing the sensor unit 3 from tilting and ensuring that the electronic interfaces 111 and 11 are correctly connected and not damaged. The retaining ribs 12 are designed to engage with the retaining clips 71 on the circular cylindrical base plate 70 of the sensor unit 3, allowing it to be releasably held in the recess 3'. The retaining clips 71 are simply slid over the retaining ribs 12.

[0092] To ensure that the sensor unit 3 can be held locked in the recess 3' and to prevent the sensor unit 3 from falling out when the rotary ring 30 is operated, corresponding locking elements 14, 14' are provided on the sensor unit 3 and the recess 3'. The recess 3' has first locking elements, namely two lugs 14 located on the inner surface of the recess 3' and projecting radially inwards (of which in Fig. 4, Fig. 9 and Fig. (only one is visible in each case). The sensor unit 3, or the rotating ring 30, has second locking means that are located on the outside of two first plates 34 and are outwardly pointing longitudinal webs 14' facing the outer surface of the recess 3' (dashed lines in Fig. 9 and Fig. 10). In the operating arrangement, the longitudinal webs 14' engage under the inwardly pointing lugs 14. The locking means can be released via release elements 32, which are designed as spring elements with ball elements (see Fig. 3 and Fig. 7).

[0093] Once the sensor unit 3 is received in the recess 3', the rotating ring 30 with its positioning elements (plates 33, 34, 36) engages the edge 15' of the recess 3'. A grip 35 is formed that encompasses the edge 15', as well as Fig. 4 indicates.

[0094] Furthermore, a circular rib 18 is located on the bottom 3" of the recess 3' in the housing cover 4, spaced a distance A from the inner surface of the recess 3'. Correspondingly, the base plate 70 of the sensor unit 3 has a groove 75 circumferentially on its side facing the bottom 3", the groove 75 receiving the circular rib 18 but not completely sealing it. This forms part of the fluid path b (measuring gas-fluid path, see Fig. 6) provided, primarily by the groove 75 communicating fluidically with at least a part of the through-openings 74 of the base plate 70. Another part of the fluid path b is formed by the distance between the lateral surface of the recess 3' and the outer lateral surface of the mantle 23 of the cover 20.

[0095] The rotating ring 30, in conjunction with the rim 15', forms another essential part of the fluid path b, as will be explained below. The rotating ring 30 has two handles 31 located opposite each other on an outer circumference of the rotating ring 30. The handle 31 allows the rotating ring 30 to be adjusted to the various positions described in Fig. 11 and Fig. 12 are shown in a) to c). The position of the handle 31 also indicates the position of the rotating ring. For this purpose, the housing cover 4 has an indicator 16 at a suitable location (see Figure 12). Fig. 4) which has pictograms incorporated into the material of the housing, so that by turning the rotary ring 30 and adjusting the handle 31 to the position corresponding to a pictogram, the mode of the sensor unit 3 is immediately clearly apparent. Fig. 11a) and b) the rotating ring 30 is in a closed position (corresponding to a test configuration, pictogram shows a stylized wrench) and in Fig. 12a) and c) the rotating ring 30 is in an open position (corresponding to a measuring configuration, pictogram shows an OK hook).

[0096] In the Fig. Figures 6 to 10, 11c) and 12c) illustrate how the arrangement of the different positioning elements of the rotary ring 30 and housing 7 changes relative to each other when the rotary ring 30 assumes the different positions. For the fluid path b, which is intended to allow the measuring gas to flow to the gas sensor 60, the rotary ring 30 can be moved into either the closed or the open position.

[0097] In Fig. 7, Fig. 8 and Fig. Figure 11c) shows the closed position in which the fluid path b from outside the gas detector 1 to the gas sensor 60 is not continuous, as is the case for a test measurement. In this position, the positioning elements 15 and the second plates 33 are offset from each other with respect to the edge 15' of the recess 3'. The gaps 33', 15" between the second plates 33 and the positioning elements 15 are not aligned. Because both gaps 33', 15" have the same dimensions, the access for the measuring gas is sealed. The offset first plates 34 and third plates 36 serve as further sealing elements within the recess 3'.

[0098] In this position, test gas can be introduced into the sensor unit 3 from outside the gas detector 1 via the test gas inlet 21. Starting from the test gas inlet 21, which corresponds to an opening 21' closable with a plug 28, the test gas can flow through an access channel 27 leading from the surface of the cover plate 20' into the interior of the lid 20, through the channel 67 along the inner surface of the ring element 65 of the receiving device 10, along the inner surface of the base plate 70 of the receiving device 10, through the recess 165', and finally to the gas sensor 60. The plug 28 is in Fig. 8 is only partially shown and is anchored in the lid 20.

[0099] In Fig. 6 and Fig. Figure 12c) shows the open position of the rotating ring 30, which corresponds to a typical measurement situation in the operating arrangement of the gas detector 1. The fluid path b is open and allows the sample gas to flow from outside the gas detector 1 to the gas sensor 60. In this position, the second plates 33 are aligned with the positioning elements 15, so that the gaps 33', 15" between the second plates 33 and the positioning elements 15 are also aligned. The further gaps 36' between the third plates 36 and the gaps 34' between the first plates 34 overlap and provide a further part of the fluid path b.

[0100] The fluid path b, represented as a black arrow in Fig. 6, runs from outside the gas warning device 1 along the overlapping gaps 33' of the second plates 33 and the gaps 15" of the positioning elements 15 and further along the overlapping gaps 36' between the third plates 36 and the gaps 34' between the first plates 34 and further along the lateral surface of the recess 3' over the web 18 through the groove 75 through the passage openings 74 to the gas sensor 60.

[0101] Furthermore, the rotating ring 30 can assume an exchange position, as shown in Fig. Figure 10 shows the locking elements, lugs 14 and longitudinal struts 14', not engaged with each other. The rotary ring 30 is turned slightly beyond the closed position and the locking elements are manually released so that the entire sensor unit 3 can be removed from the recess 3'.

[0102] In the Fig. 13, Fig. 14 and Fig. Figure 15 shows another housing 7 for the gas warning device 1, the general structure of the gas warning device 1 shown there being that of the one in Fig. The gas warning device 1 shown in 1 to 3 corresponds to the housing 7 of the device shown in Fig. 13, Fig. 14 and Fig. The gas warning device 1 shown in Figure 15 has a compact design and requires no hinges or other additional connecting elements. The housing cover 4 has a recess 3' in which the sensor unit 3 can be inserted. The underlying housing body 5, in whose recess 5" the housing 9' of the communication electronics 9 is received, can be screwed or plugged together with the housing cover 4. Connection sockets 7' are arranged in the housing body 5, by means of which the communication electronics 9 can be connected to the central unit 80 via the electrical connection 81 (in Fig. 14 (both shown with dashed lines). Together with the central unit 80, the gas warning device 1 forms the gas warning system 100.

[0103] The housing 7 is attached to the mounting plate 8, which has openings 8' for screwing the housing body 5 to the mounting plate 8. The mounting plate 8 has mounting holes 8" which serve to mount the housing 7 of the gas detector 1, for example, to a wall.

[0104] The protective cover 2 is placed over the housing cover 4. This cover has a multitude of parallel, curved struts 2' that bridge the underlying sensor unit 3 and provide protection against damage. Between the struts 2' are, as in the Fig. 1 and Fig. 2 openings already shown, which space the webs 2' apart.

[0105] In Fig. Figure 15 shows the gas detector 1 in the same cross-section as Fig. 5, wherein the sensor unit 3 is inserted in the recess 3' of the housing cover 4 and the electronic interface 11 of the sensor unit is connected to the electronic interface 111 of the recess 3' of the housing cover 4. In this embodiment, the housing cover 4 sits directly on the housing body 5, which also carries the connection sockets 7'. The other components correspond to the description above. Fig. 5. REFERENCE MARK LIST 1 gas detector 2 protective covers 2' curved bridges 2" openings 3 Sensor unit 3' corresponding recess 3" bottom 4 Housing covers 5 Housing bodies 5' hinges 5" cutout 6 Housing lower part 7 cases 7' connection sockets 8 Mounting plate 8' openings 8" openings 9 Communication Electronics 9' Housing Communication Electronics 10 Recording device 11 electronic interface recess 111 electronic interface sensor unit 12 landing stages 13 gully 14 Nose 14' Longitudinal ribs 15 Positioning element 15' Edge of the recess 15" gap between positioning elements 16 ads 17 Battery 18 Bridge 20 lids 20' cover plate 21 Test gas access 21' Opening 22 deployment 23 circular cylindrical mantle (of the lid 20) 24 rest recess 25 cone 26 slots for speakers 27 Access channel 28 plugs 30 rotating ring 31 handle 32 Release element 33 Positioning element / second plate 33' gap between second plates 34 Positioning element / first plates 34' gap between first plates 35 Circumference 36 Positioning element / third plates 36' gap between third plates 40 processor boards 41 speakers 42 slots 43 U-shaped cutout 44 Speaker seal 50 Sensor board / control and data processing unit 60 Gas sensor 60' measuring tube tray 61 Measuring tube 62 Screw connection 63 Measuring tube holder 64 light source 65 Ring element 65' flange 66 slots 67 gully 68 Groove / Sealant Receptacle 69 Guide Sensor board 70 Base plate 70' recess electronic interface 70" thickened rim 71 retaining brackets 71' upper edge 71" side edge 72 lead 74 passageways 75 Nut 80 Central unit 81 electrical connection 100 Gas warning device 165 Bottom section of the ring element 165' recess 411 electronic interface processor board 511 electronic interface sensor board A distance a fluid path test gas b Fluid path measuring gas

Claims

[1] Sensor unit (3) designed for arrangement in a gas warning device (100), which has a gas sensor (60), characterized by , that the sensor unit (3) comprises a circular cylindrical receiving device (10) and a cover (20) which has a cover plate (20'), wherein the gas sensor (60) and at least one control and data processing unit (50) which is in communicative connection with the gas sensor (60) are arranged in the circular cylindrical receiving device (10), and - the cover plate (20') has a test gas access (21) through which a fluid path (a) for a test gas is provided to the gas sensor (60), and wherein the circular cylindrical receiving device (10) provides a fluid path (b) for a measuring gas to the gas sensor (60), wherein the sensor unit (3) has an electronic interface (111) located on the circular cylindrical receiving device (10), which is designed to be communicatively connected to a corresponding electronic interface in a user arrangement. [2] Sensor unit (3) according to claim 1, characterized by , that the sensor unit (3) in the circular cylindrical receiving device (10) has a measuring tube (61) which provides a measuring section for the measuring gas in the fluid path (b) for the measuring gas to the gas sensor (60). [3] Gas warning device (1) comprising a sensor unit (3) according to claim 1 or 2, characterized in that the gas warning device (1) - a housing (7) comprising a housing cover (4), a housing body (5), and a housing base (6), wherein - the housing (7) in the housing cover (4) has a recess (3') with a base (3") which has an electronic interface (11), and that - the recess (3') has first locking means and the sensor unit (3) has second locking means which can be releasably engaged with the first locking means, and whereby the housing (7) and the circular cylindrical receiving device (10) of the sensor unit (3) provide the fluid path (b) for the measuring gas to the gas sensor (60), and the electronic interface (11) of the base (3") in an operating arrangement in which the sensor unit (3) is detachably received in the recess (3') of the housing (7), is in communicative contact with the electronic interface (111) present on the circular cylindrical receiving device (10). [4] Gas warning device (1) according to claim 3, characterized by , that the circular cylindrical receiving device (10) - a ring element (65) with a bottom section (165) in which at least one recess (165') is provided through which the fluid path (b) for the measuring gas passes and which is designed to provide a passage for the electronic interface (11) of the bottom (3") of the housing cover (4) for connection with the electronic interface (111), - a circular cylindrical base plate (70) which has a plurality of retaining means, preferably retaining brackets (71), in which a recess (70') is provided in the circular cylindrical base plate (70) which is designed to provide a passage for the electronic interface (11) of the bottom (3") of the housing cover (4) for connection with the electronic interface (111), and in which a plurality of passage openings (74), designed to allow the measuring gas to pass through, are provided in the circular cylindrical base plate (70), and in which the ring element (65) sits on the circular cylindrical base plate (70), preferably on a thickened circumferential edge (70") of the circular cylindrical base plate (70). [5] Gas warning device (1) according to claim 4, characterized by , that the ring element (65) has an outer flange (65') on its edge facing the bottom section (165), and a circular cylindrical mantle (23) of the lid (20) which supports the cover plate (20'), supported against the flange (65'), preferably on a sealing medium resting on the flange, particularly preferably on a sealing ring (68). [6] Gas warning device (1) according to claim 5, characterized by , that a rotating ring (30) is rotatably arranged circumferentially around the outer surface (23) of the cover (20), preferably projecting through the cover plate (20'), and in the operating arrangement rests against an edge (15') of the recess (3') in the housing (7), preferably rotatably resting on it by means of an outer circumferential grip (35) of the rotating ring (30), wherein the rotating ring (30) has at least two types of positioning elements (33, 34), preferably three types of positioning elements (33, 34, 36) which, in conjunction with positioning elements (15) that the housing (7) has, determine a position of the rotating ring (30) in relation to the recess (3'). [7] Gas warning device (1) according to claim 6, characterized by , that the positioning elements of all types (33, 34, 36) are first plates (34), second plates (33) and / or third plates (36) extending from a bottom surface of the rotating ring (30) facing the circular cylindrical base plate (70) in the direction of the circular cylindrical base plate (70), wherein - the first plates (34) are arranged radially closer to a center point of the rotating ring (30) on the underside of the rotating ring (30), preferably on an inner circumference of the rotating ring (30), and are spaced apart from each other by gaps (34') than the second plates (33), which are also spaced apart from each other by gaps (33') on the underside of the rotating ring (30), preferably on its outer circumference, wherein preferably the gaps (34') between the first plates (34) and the gaps (33') between the second plates (33) are not congruent, and wherein, particularly preferably with respect to an axial extent of the plates (33, 34), the second plates (33) are shorter than the first plates (34). [8] Gas warning device (1) according to claim 7, characterized by , that The third plates (36) extend from an underside of the rotating ring (30) facing the circular cylindrical base plate (70) in the direction of the circular cylindrical base plate (70), wherein the third plates (36) are arranged radially to the center of the rotating ring (30) between the first plates (34) and the second plates (33) and are spaced apart from each other by gaps (36') on the underside of the rotating ring (30), wherein preferably the gaps (34') between the first plates (34) and the gaps (33') between the second plates (33) are not congruent with the gaps (36') between the third plates (36), and wherein particularly preferably With respect to the axial extent of the plates (33, 34, 36) the third plates (36) are shorter than the first plates (34). [9] Gas warning device (1) according to at least one of claims 6 to 8, characterized by, that the positioning elements (15) are distributed around the outer circumference of the edge (15') of the recess (3') and are spaced apart from each other by gaps (15"). [10] Gas warning device (1) according to at least one of claims 4 to 9, characterized by , that retaining ribs (12) are distributed on the base (3") on an inner lateral surface of the recess (3') of the housing (7), which extend longitudinally axially in relation to the inner lateral surface, which engage with the retaining means of the circular cylindrical base plate (70), which are preferably retaining brackets (71), for releasably holding the sensor unit (3) in the recess (3'). [11] Gas warning device (1) according to at least one of claims 4 to 10, characterized by , that on the bottom (3") of the housing (7) in the housing cover (4) there is a circular rib (18) which is spaced at a distance (A) from the inner lateral surface of the recess (3'), and wherein the circular cylindrical base plate (70) of the sensor unit (3) has a groove (75) circumferentially on its side facing the ground (3") which communicates fluidically with at least a part of the passage openings (74) of the circular cylindrical base plate (70), wherein the groove (75) accommodates the circular rib (18) of the base (3") of the housing (7). [12] Gas warning device (1) according to at least one of claims 6 to 11, characterized by , that the first locking means which the recess (3') has are elements located on an inner surface and pointing radially inwards, preferably projections or lugs (14), and the second locking means that the sensor unit (3) has are located on at least two of the positioning elements (34), which are first plates (34), wherein the second locking means are preferably longitudinal webs (14') located on an outside of the first plates (34), and wherein, when the first locking means engage with the second locking means, the longitudinal webs (14') engage under the inwardly pointing elements, preferably the projections or lugs (14). [13] Gas warning device (1) according to at least one of claims 6 to 12, characterized by , that the rotating ring (30) is in relation to the recess (3') in a - can be brought into an open position in which the fluid path (b) for the measuring gas is continuous from outside the gas warning device (1) to the gas sensor (60), wherein in the open position the positioning elements (15) which the housing (7) has and the positioning elements (33) are aligned with each other, - can be brought into a closed position in which the fluid path (b) for the measuring gas from outside the gas warning device (1) to the gas sensor (60) is not continuous, wherein the positioning elements (15) which the housing (7) has and the positioning elements (33) are positioned offset from each other circumferentially with respect to the edge (15') of the recess (3'), - The exchange position can be brought into which the first locking means are not engaged with the second locking means. [14] Gas warning device (1) according to at least one of claims 3 to 13, characterized by , that a battery (17) is arranged in the circular cylindrical receiving device (10). [15] Gas warning device (1) according to at least one of claims 3 to 14, characterized by, that an output device, preferably an optical and / or an acoustic output device, is provided in the sensor unit (3) and / or on the housing (7), which is communicatively connected to the control and data processing unit (50) and is configured to optically and / or acoustically output measured values ​​of the gas sensor (60) and / or position data acquired by position sensors, which are provided on the housing (7) and are configured to detect a respective position of the rotating ring (30), and which are communicatively connected to the control and data processing unit (50). [16] Gas warning device (100) comprising at least one gas warning device (1) according to one of claims 3 to 15 and a data processing central unit (80), wherein the gas warning device (1) is communicatively connectable to the central unit (80). [17] Method for performing a maintenance operation on a gas warning device (1) according to at least one of claims 3 to 15, comprising the steps - the first locking means which has the recess (3') and the second locking means which has the sensor unit (3) and which can be releasably engaged with each other, release each other, - Removing the sensor unit (3) with the gas sensor (60) from the recess (3') of the housing (7) and - Inserting a new sensor unit (3) with a new gas sensor (60) into the recess (3') of the housing (7), - engage the first locking means which has the recess (3') and the second locking means which has the sensor unit (3) and which can be detachably brought into engagement with each other. [18] Method for performing a gas measurement with a gas warning device (1) according to at least one of claims 6 to 15, wherein the gas measurement is a testing of the gas sensor (60) with the test gas or a measurement with the measuring gas, comprising the steps in a first phase - Bring the rotating ring (30) into a closed position in which the fluid path (b) for the measuring gas from outside the gas warning device (1) to the gas sensor (60) is not continuous, wherein the positioning elements (15) having the housing (7) and the positioning elements (33) are positioned circumferentially offset from each other in relation to the edge (15') of the recess (3'), - Supply of the test gas through the test gas access (21) for the test gas under the cover plate (20'), through which a fluid path (a) for the test gas to the gas sensor (60) is provided, to the gas sensor (60), - Detection of the test gas with the gas sensor (60) and generation of a measurement signal, - Output of a measured value correlated with the measurement signal by the control and data processing unit (50), in a second phase - Bring the rotating ring (30) into an open position in which the fluid path (b) for the measuring gas from outside the gas warning device (1) to the gas sensor (60) is continuous, wherein in the open position the positioning elements (15) which the housing (7) has and the positioning elements (33) are aligned with each other, - allowing the measuring gas to flow along the fluid path (b) for the measuring gas to the gas sensor (60), - Detection of the measuring gas with the gas sensor (60) and generation of a measurement signal, - Output of a measured value correlated with the measurement signal by the control and data processing unit (50), The first and second phases can also be carried out in reverse order or at a time interval. [19] Method according to claim 18, wherein the fluid path (b) for the measuring gas runs from outside the gas warning device (1) along the overlapping gaps (33') between the second plates (33) and the gaps (15") of the positioning elements (15) and further along the overlapping gaps (36') between the third plates (36) and the gaps (34') between the first plates (34) and further along the inner surface of the casing over the circular web (18) through the passage openings (74) to the gas sensor (60).

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