Gas density meter

Abstract

The invention relates to a gas densitometer (100, 200) for monitoring the pressure or density of a gas in a gas chamber (1), comprising: a housing (102, 202) having a first housing cavity (103, 203) and a measurement chamber (168, 268); a first coupling (104, 204) via which the measurement chamber can be connected to the gas chamber; at least one reference flap (105, 205), which is in particular directly or indirectly connected to the transmission element (109, 209); and at least one switching and / or monitoring unit (110, 210), which is held or can be operatively connected to the transmission element directly or indirectly. The measuring chamber is connected to the gas chamber in a gas-permeable manner via a first coupling, and the reference bellows forms a reference chamber (111, 211) which is filled with a constant amount of reference gas. A surface section covering the reference chamber is provided or can be implemented as a measuring surface for gas from the measuring chamber at least in some regions inside the first housing chamber or the measuring chamber.

Description

Technical Field

[0001] The present invention relates to the technical field of measuring and monitoring the gas density of a gas in a hermetically closed gas chamber with a constant volume. Background Art

[0002] A gas densitometer is a pressure measuring device designed to measure and / or display the density of a gas in a hermetically sealed, constant-volume gas chamber. Various methods are known in the prior art for compensating for pressure changes caused by temperature variations in the gas. Through temperature compensation, which must be coordinated with the specific properties of the respective gas type, a measured, compensated pressure becomes equivalent to a gas density and can also be converted or rescaled to this gas density.

[0003] Gas density meters that additionally have a limit value signal generator for reporting when a limit value is exceeded or fallen below are also called gas density monitors. Such gas density monitors usually have an electrical contact device to which an external cable can be connected, via which the signal can be transmitted to an external monitoring and / or control device.

[0004] A gas chamber filled with a gas whose density is to be monitored is typically characterized by a defined pressure value that can be assigned to the normal operating state of the gas chamber. This pressure value is also referred to as the nominal pressure, filling pressure, or operating pressure and is typically defined for a specific gas temperature.

[0005] In order to detect possible leakage or emission of the filling gas early, the density in the gas chamber is monitored, for example, by means of a gas density monitor, and a corresponding limit value signal is triggered when the density falls below a defined limit value which is less than the nominal pressure.

[0006] Gas density meters and monitors are used, for example, in gas-insulated switchgear for medium- and high-voltage applications. Monitoring the insulating gas density is crucial not only to ensure the insulating effect of the gas but also to prevent environmentally harmful emissions. In this area, gas density meters and monitors are particularly useful for monitoring gas chambers filled with sulfur hexafluoride (SF6). SF6 is a widely used insulating gas due to its physical properties.

[0007] Gas density meters, gas density displays and gas density monitors are well known in the art.

[0008] EP 2 796 852 B1 discloses a temperature-compensated density monitor comprising a chamber with a variable volume connected to a gas chamber. The chamber expands when the applied pressure increases, simultaneously pressing against a spring. The spring is a shape memory spring. The special properties of this spring are intended to achieve temperature compensation.

[0009] CN 207116321 U discloses a density monitor comprising a chamber of variable volume filled with a reference gas. This is intended to achieve temperature compensation. The chamber is formed by two coaxially arranged bellows, one bellows surrounding the other.

[0010] CN 107968018 A discloses a gas density monitor comprising an arrangement in which two pleated bladders are arranged in a housing having two housing cavities. The first pleated bladder is connected to an inner wall section of the first housing cavity at one end and is sealed at the other end by a connecting element and gas-permeable to a gas chamber. The first pleated bladder thus forms a first chamber. The second pleated bladder is also sealed at one end by a connecting element and is connected at its other end to the other inner wall section of the first housing cavity. A second chamber is formed by the outer sides of the two pleated bladders, the surface of the connecting element, and the inner wall of the first housing cavity, and is filled with a reference gas. In this way, temperature compensation is intended to be achieved. Summary of the Invention

[0011] The object of the present invention is to specify a gas density meter which is improved compared to the prior art.

[0012] This object of the present invention is achieved by a gas density meter according to claim 1 or 2 .

[0013] Possible developments of the invention are the subject matter of the dependent claims.

[0014] According to a first aspect of the present invention, a gas densitometer for monitoring the pressure or density of a gas in a gas chamber comprises a housing having a first housing cavity and a measuring chamber. Furthermore, the gas densitometer comprises: a first connector via which the measuring chamber can be connected to the gas chamber; at least one reference pleat, which is connected, for example, directly or indirectly, to a transfer element; and at least one conversion and / or monitoring unit, which is directly or indirectly connected to or capable of being operatively connected to the transfer element. According to the present invention, the measuring chamber is gas-permeably connected to the gas chamber via the first connector, and the reference pleat constitutes a reference chamber filled with a constant amount of reference gas. A surface section covering the reference chamber is provided or can be realized as a measuring surface for gas from the gas chamber, at least partially within the first housing cavity or the measuring chamber.

[0015] According to a second aspect of the present invention, a gas densitometer for monitoring the pressure or density of gas in a gas chamber includes a housing including at least one first housing cavity, which forms a measuring chamber. The gas densitometer further includes at least one first coupling via which the gas densitometer can be connected to the gas chamber; and at least one first bellows, which may be referred to as a reference bellows, which is directly or indirectly connected at a first end section to a first inner wall section of the first housing cavity of the measuring chamber. The gas densitometer further includes at least one isolating means, which is directly or indirectly connected to or formed by a second end section of the reference bellows; at least one transmission element, which is directly or indirectly connected to the isolating means; and at least one switching and / or monitoring unit, which can be operatively connected directly or indirectly to the transmission element. The measuring chamber is gas-permeably connected to the gas chamber via the first coupling, and the reference bellows forms a reference chamber, which is filled with a constant amount of reference gas. The reference chamber is at least partially disposed within the first housing cavity and is gas-tightly isolated from the measuring chamber.

[0016] According to a third aspect of the present invention, a gas densitometer for monitoring the pressure or density of gas in a gas chamber includes a housing comprising at least one first housing chamber. Furthermore, the gas densitometer includes at least one first coupling via which the gas densitometer can be connected to the gas chamber; and a first fold, which can be referred to as a reference fold and is directly or indirectly connected at a first end section to a first inner wall section of the first housing chamber. Furthermore, the gas densitometer includes a second fold, which can be referred to as a measuring fold and is directly or indirectly connected at a first end section to a second inner wall section of the first housing chamber. Furthermore, the gas densitometer includes at least one isolating means, which is directly or indirectly connected to the second end section of the reference fold and the second end section of the measuring fold, or is formed via the second end section of the reference fold or the second end section of the measuring fold. Furthermore, the gas densitometer includes a transmission element, which is directly or indirectly connected to the isolating means; and at least one conversion and / or monitoring unit, which can be operatively connected directly or indirectly to the transmission element. The reference bellows forms a reference chamber which is filled with a constant amount of reference gas, and the measuring bellows forms a measuring chamber which is gas-permeably connected to the gas chamber via a coupling, wherein the measuring chamber and the reference chamber are gas-tightly isolated from one another.

[0017] The term "housing" is currently understood to mean, in particular, a jacket comprising one or more housing parts, such as a base body and a cover and / or a bottom and / or a housing extension. A housing cavity is currently understood to mean, in particular, all interior volumes of a one-piece housing or a multi-piece housing, which are connected to one another in an airtight manner.

[0018] The gas density meter according to the first, second or third aspect of the present invention has the advantage of providing a modular structure with a small number of components, low manufacturing costs and high reliability and operational safety.

[0019] Unlike known gas densitometers and monitors, the gas densitometer according to the invention can be manufactured simply and at low production costs. Furthermore, unlike gas densitometers and monitors known from the prior art, even in the event of a fault, a signal and / or display corresponding to the actual state of the device and / or indicating a fault in the gas densitometer is provided.

[0020] In this case, the gas density meter can be designed in particular for measuring and / or monitoring the density of single-component or multi-component gases, wherein gases such as sulfur hexafluoride (abbreviation: SF6), nitrogen, air, molecular gases such as (CF3)2CFCN or gas mixtures are suitable.

[0021] The introduction of insulating gas from the gas chamber into the measuring chamber via the connector is suitable for three aspects of the invention. Here, the measuring chamber is formed by the first housing in the first and second aspects of the invention and by the measuring bellows in the third aspect.

[0022] The insulating gas in the measuring chamber exerts pressure on the surface of the insulating means or on the surface of a component having a corresponding surface section.

[0023] The reference gas enclosed in the reference chamber, ie in the reference bellows, in turn exerts pressure on the opposite surface of the separating means or on the opposite surface of the component having the corresponding surface section.

[0024] The system thereby seeks a state in which a balance of forces exists.

[0025] The pressure exerted on the surface of the isolating mechanism or on the surface of the component having the corresponding surface section is determined directly by the pressure of the introduced insulating gas, while the pressure exerted on the opposite side of the isolating mechanism or on the opposite side of the component having the corresponding surface section is varied by the reference gas in such a way that the volume of the reference chamber changes.

[0026] In this case, the reference bellows compresses or expands over a long period of time under the influence of the pressure exerted on the surface of the separating means or on the surface of the component having the corresponding surface section, until a force equilibrium exists.

[0027] The translational movement of the separating device or of the component with the corresponding surface section during the compression or expansion of the reference bellows is mechanically transmitted to the switching and / or monitoring unit via the transmission element.

[0028] If the pressure of the insulating gas from the gas chamber drops, the reference bellows expands. This causes the separating means or a component having a corresponding surface section to move upward, for example. If the pressure of the insulating gas from the gas chamber rises, the reference bellows compresses, and the separating means or a component having a corresponding surface section to move downward.

[0029] If the temperature of the gas in the gas chamber changes, this will always result in a pressure increase, since the gas chamber is generally a gas-tight, constant-volume container. Likewise, cooling of the gas in the gas chamber results in a pressure decrease.

[0030] However, these pressure changes do not correspond to changes in gas density, ie, to a gain or loss of gas, which should nevertheless be monitored. Therefore, these pressure changes caused by temperature changes must be compensated.

[0031] This is achieved by enclosing a reference gas in the reference chamber. This reference gas is in thermal contact with the gas chamber and the insulating gas via the walls of the reference bellows and the entire housing. When the temperature of both the insulating gas and the reference gas rises, that is, when the measuring and reference chambers are in thermal equilibrium, the pressure in the reference chamber rises to the same degree as the pressure in the measuring chamber. Consequently, temperature-induced pressure changes do not result in pressure changes on the surfaces of the isolating means or components having corresponding surface sections, and the isolating means or components do not undergo translational movement.

[0032] A prerequisite for precise temperature compensation is that the reference gas experiences the same pressure increase as the insulating gas under temperature changes. For example, a gas that is also present in the gas chamber is used as the reference gas.

[0033] Unless otherwise stated, the possible embodiments of the gas density meter described below can be used for all three aspects of the invention.

[0034] In one possible embodiment of a gas density meter, the gas density meter is designed to be mounted on a gas chamber, wherein a gas chamber is to be understood in particular as a closed, i.e., environmentally sealed, gas chamber in or on an electrical switching device, which is filled with a gas at a defined pressure. This allows for simple mounting of the gas density meter on such a switching device and particularly reliable measurement and / or monitoring of the gas density.

[0035] In another possible design of a gas density meter, the housing is formed in one piece or assembled from multiple pieces. For example, the housing or its parts may be made of a metal material such as brass, aluminum, steel, or high-grade steel. However, the housing parts may also be made of plastic, ceramic, composite materials, or glass. This allows for simple adjustment of the housing's resistance to different media.

[0036] Another possible embodiment of the gas density meter provides that the at least one first housing is designed as a cavity in the housing, which is gas-permeable to the coupling but otherwise sealed from the environment and / or further housings. The housing, for example, has a cylindrical form that can be easily and economically manufactured. In the case of a cylindrical form, the gas-permeable connection to the coupling can be provided on a wall section of the outer circumference or on one of the flat end faces of the cylinder.

[0037] In another possible design of a gas densitometer, the coupling is configured as a joint for mounting the gas densitometer on the gas chamber. Such a joint can be implemented, for example, by means of an internal or external thread, a flange joint, or a plug coupling. The coupling can also be provided with a self-sealing valve, so that when the coupling is removed or detached from a corresponding coupling on the gas chamber that opens it, the connection to the measuring chamber is severed. The coupling itself can also be configured to open a self-sealing valve on a corresponding coupling on the gas chamber. The coupling enables reliable, secure, and simple connection of the gas densitometer to the gas chamber.

[0038] In another possible embodiment of the gas density meter, the reference bellows is directly or indirectly connected at its first end section to a first inner wall section of the first housing or measuring chamber. This connection is gas-tight and therefore airtight, for example, a welded connection, a soldered connection, a clamped or pressed connection, an adhesive connection, a screw connection, or a connection with a sealing element. This ensures the tightness of the connection in a simple and reliable manner. It is provided that, in this embodiment, the first inner wall section does not enclose the inner wall region in which the connection between the first housing and the coupling is established.

[0039] In another possible design of a gas densitometer, the reference bellows is directly connected to an inner wall section of the measuring chamber by a housing extension. The housing extension can, for example, have a pot-like, cap-like, or bowl-like shape and is connected to the housing, in particular closing an opening in the housing wall. This arrangement allows the measuring chamber to be located only partially within the corresponding housing cavity, or even for only the transfer element to extend into the measuring chamber. This allows for a particularly compact measuring chamber. It is also particularly simple to manufacture and assemble.

[0040] In another possible embodiment, the respective bellows are integrally closed at at least one end, with their respective end sections forming the separating means.

[0041] Another possible embodiment of the gas densitometer provides for the separating means to be designed as a plate-shaped, in particular disk-shaped or plate-shaped, one-piece or multi-part element. Such a disk-shaped or plate-shaped element has the advantage that it can be easily connected to the end section of a bellows having a circular cross-section. Multi-part means, for example, that the connection between the separating means, the reference bellows, and the transmission element can each also be designed indirect, and that additional supplementary components, such as connecting rings or the like, can be assigned to the separating means as a multi-part separating means.

[0042] The isolating mechanism or its components are, for example, made of a metal material such as brass, aluminum, steel, or high-quality steel. However, the isolating mechanism or its components can also be made of plastic or composite materials. In addition, in this design, it can be provided that the connection between the isolating mechanism and the second end section of the reference fold is particularly airtight and thus airtight, such as a welded connection, a soldered connection, a clamped or pressed connection, an adhesive connection, a threaded connection, or a connection with a sealing element. This ensures the tightness of the connection in a simple and reliable manner. The design features of this airtight connection can also be applied to the connection between the isolating mechanism and the second end section of the measuring fold, as well as to the connection between the first end section of the measuring fold and the inner wall section of the first housing. However, it is applicable here that the different connections between the fold, the isolating mechanism, and the different inner wall sections do not need to be made identically or in the same manner within a single design.

[0043] In another possible design of the gas densitometer, it is provided that the transmission element is constructed as a one-piece element, such as a pin, a rod, a push rod or a toothed rack. As an alternative, it is provided that the transmission element is constructed as a multi-piece element, which includes at least two elements and at least one joint, hinge or suspension device or support device. In addition, it can be provided that the direct or indirect connection between the transmission element and the isolation mechanism is a releasable or flexible connection, such as a threaded connection, a movable support or a plug connection. However, a non-releasable connection, such as a welded connection or an adhesive connection can also be provided. The multi-piece design of the transmission element with a joint or similar components has the advantage that the movement of at least one of the bellows and / or isolation mechanism can be specifically transmitted to the conversion and / or monitoring unit even in the case of a relatively complex housing structure.

[0044] Another possible design of the gas densitometer provides for the switching and / or monitoring unit to be constructed as a multi-part unit having an operating mechanism and a display device with a pointer, and / or as a multi-part unit having a switching element and a contact device. The display device allows the real-time gas density value to be read on the gas densitometer at any time and from any location. The multi-part unit having the switching element and the contact device can trigger an electrical signal at a predefined density limit value, which can be detected by an external control unit via electrical wiring, thereby enabling remote monitoring.

[0045] In another possible embodiment of the gas density meter, provision is made for the operative connection between the transmission element and the conversion and / or monitoring unit to be achieved by mechanical contact between the transmission element and the conversion and / or monitoring unit or a part thereof, in particular by transmitting a force or torque to the conversion and / or monitoring unit or a part thereof, or by transmitting a motion via a rack gear. However, provision can also be made for the operative connection between the transmission element and the conversion and / or monitoring unit to be achieved by a contactless operative connection, for example by electromagnetic interaction, by means of a magnetostrictive travel sensor, or by optical detection.

[0046] Another possible design of a gas densitometer provides for a reference bellows to be connected directly or indirectly with its first end section to a first inner wall section of the first housing or measuring chamber, and directly or indirectly with its second end section to a separating element, forming a variable-volume reference chamber that is sealed from the environment, the first housing, and / or the further housing. In other words, the reference bellows is designed as a closed reference chamber, wherein one open end of the reference bellows is closed by connection to the housing inner wall, and the other open end is closed by connection to the separating element. Furthermore, it may be provided that a constant amount of reference gas is enclosed in the reference chamber. A constant amount in this context means a constant amount of substance, i.e., a constant amount of particles or a constant mass. The reference gas may, for example, be of the same type or a gas mixture as the gas in the gas chamber (the density of which is to be monitored by the gas densitometer). This means, for example, that the reference gas is the same gas as the insulating gas to be monitored. For example, the two gases may have approximately identical, and in particular, identical, thermal expansion characteristics.

[0047] In a possible design of a gas densitometer according to the first aspect, the surface segment covering the reference bellows has an effective measuring area that is 2% to 80% smaller, particularly 5% to 50% smaller, particularly 10% to 45% smaller, and particularly 15% to 30% smaller, than the cross-sectional area of ​​the reference bellows or the surface segment covering it. This means that the insulating gas from the gas chamber can no longer be pressed against the entire surface of the corresponding surface segment in the measuring chamber. The resulting pressure is therefore lower than if this pressure were to act on the entire surface. However, the reference gas within the reference chamber can be pressed against the entire surface of the corresponding surface segment, at least within the diameter of the reference bellows. This means that, in the force balance, a lower pressure is generated in the reference chamber than in the measuring chamber. This has the advantage that, in the event of a fault, such as a leak between the measuring and reference chambers, and the resulting slow pressure balance between the chambers, a pressure increase in the reference chamber occurs. However, this then results in a translation of the component containing the surface segment, which is equivalent to the pressure drop in the measuring chamber in the normal case. In conjunction with the expansion of the measuring range to lower pressures achieved by means of a spring element provided in accordance with one possible embodiment, the result is that the pressure of the insulating gas drops below the pressure in the reference chamber from a specific point. However, the gas volume in the reference chamber, the ratio of the free surfaces against which the insulating gas and reference gas press, and the spring strength of the spring element can advantageously be coordinated such that the pressure in the reference chamber is lower than the pressure in the measuring chamber, at least when the measuring chamber pressure corresponds to the normal operating pressure of the device.

[0048] In another possible embodiment of the gas densitometer according to the first aspect, the component having the surface section is formed, for example, by means of the already described separating means, or the component comprises such a separating means, or the separating means comprises the component.

[0049] In another possible embodiment of the gas densitometer according to the first aspect, the reference bellows has a diameter of 20 mm to 70 mm, or 30 mm to 63 mm, or 35 mm to 55 mm.

[0050] In another possible embodiment of the gas density meter according to the first aspect, the reference bellows has an effective measuring area or cross-sectional area perpendicular to the axis of the transmission element, which has a cross-sectional area of ​​3 cm 2 Up to 40cm 2 or 7cm 2 Up to 30cm 2 or 10cm 2 Up to 25cm 2 area.

[0051] In another possible embodiment of the gas densitometer according to the first aspect, the pressure of the reference gas in the reference bellows is, during normal operation of the gas chamber, 0.05 bar to 2.5 bar, 0.5 bar to 1.0 bar, or 0.2 bar to 0.5 bar lower than the connection pressure of the gas chamber. This makes it possible to particularly easily detect faults in the gas densitometer that result in a gas-permeable connection between the reference chamber and the first housing.

[0052] In another possible embodiment of the gas density meter according to the first aspect, the reference bellows is completely surrounded by the housing or the housing space in a gas-tight manner.

[0053] In another possible embodiment of the gas density meter according to the first aspect, the conversion and / or monitoring unit includes at least one switching element, wherein the at least one switching element is actuated directly or indirectly by means of a transmission element when pressure equalization occurs between the measuring chamber and the reference chamber. The switching element enables an electrical switching signal to indicate reaching the limit pressure, thereby enabling remote monitoring, for example.

[0054] In another possible design of the gas densitometer according to the first aspect, at least one first spring element is provided, which applies a spring force to the reference bellows that counteracts its expansion. Optionally or additionally, at least one second spring element is provided, which applies a spring force to the reference bellows that counteracts its compression. This advantageously allows the measuring range of the gas densitometer to be expanded either toward lower pressure or toward higher pressure. Without the spring element and its force, the measuring range of the gas densitometer would be limited to a narrow range of a few bar, since the reference bellows can only elastically expand or compress to a limited extent. Increasing the spring force can reduce the expansion or compression of the reference bellows, or the accompanying volume change of the reference chamber, and the resulting pressure change in the reference chamber, required to achieve force equilibrium with the existing pressure in the measuring chamber. This means that, in addition to the pressure, the spring force acts on one or both surfaces of the component having the surface section. These spring forces are linearly dependent on the compression of the spring element. The translation of the component with the surface section required for the force compensation and the accompanying volume change of the reference chamber can be reduced by compressing the spring more and more and thereby exerting an increasingly greater spring force on the component with the surface section.

[0055] If, for example, the spring element is arranged so that it presses from above onto a component having a surface section, it will be increasingly compressed as the pressure in the upper measuring chamber drops. The pressure of the reference gas counteracts not only the decreasing pressure of the insulating gas but also the increasing spring force. The spring element is dimensioned so that, with a constant maximum expansion of the bellows and a defined minimum insulating gas pressure, a force balance is always achieved.

[0056] In a possible embodiment of the gas density meter according to the second aspect, it is provided that the interior of the first housing—which is isolated from the reference chamber by the reference bellows, by a direct or indirect connection of the first end section of the reference bellows to a first inner wall section of the first housing chamber or the measuring chamber, and by a direct or indirect connection of the second end section of the reference bellows to the separating means—forms a variable-volume measuring chamber and is gas-permeably connected to the gas chamber via a coupling. In other words, the measuring chamber is generated by the housing, in particular, by the separation of the reference bellows, which is achieved by connecting the reference bellows to the housing inner wall and the separating means.

[0057] In a possible design scheme of the gas density meter according to the third aspect of the present invention, it is stipulated that the measuring folded bag is connected with its first end section directly or indirectly to the first inner wall section of the first shell cavity and with its second end section directly or indirectly to the isolation device to form a variable-volume measuring chamber, which is sealed relative to the environment, the first shell cavity and / or the other shell cavity and the reference folded bag and is gas-permeable to the gas chamber via a connector.

[0058] In another possible embodiment of the gas densitometer, the switching and / or monitoring unit includes at least one switching element and, for each switching element, at least one electrical contact device assigned to the switching element. The at least one switching element can be actuated directly or indirectly via a transmission element, and the at least one electrical contact device is electrically connected to the switching element and accessible from outside the housing. In particular, the at least one switching element is actuated at a predetermined limit pressure by means of an isolating mechanism, so that an electrical switching signal indicates that a limit pressure has been reached, thereby enabling remote monitoring, for example.

[0059] Another possible embodiment of the gas density meter provides that the switching and / or monitoring unit additionally includes at least one radio device connected to at least one switching element, which detects the switching state of the switching element and transmits it as a radio signal. This eliminates the need for expensive cables, thereby reducing space requirements and installation costs. This also offers the advantage that the gas density meter can also be used as a gas density monitor. The at least one switching element can be assigned a gas density limit value critical for the operation of the gas chamber and monitored via a wired or radio connection.

[0060] To enable a compact design of the gas densitometer, individual adjustment and / or calibration of each individual switching point, and economical production, another possible embodiment of the gas densitometer provides that the switching element is designed as a mechanical switch, particularly a microswitch or a pushbutton switch, and is directly or indirectly operatively connected to the transmission element, such that the transmission element mechanically actuates the switching element. Furthermore, it can be provided that the switching element is disposed, for example, on a support element, particularly a circuit board. The transmission element can include, for example, an operating element, particularly also in the form of a circuit board or in the form of an arm, plate, or spacer. Furthermore, the transmission element can include at least one associated pushbutton unit for each switching element included in the switching and / or monitoring unit, which allows adjustment of its position relative to the transmission element and / or the operating element. In a possible embodiment of this refinement, it can also be provided that the switching element is configured for contactless operative connection with the transmission element and thus operates frictionlessly and, in particular, wear-free. The switching element can include, for example, a reed switch or a Hall element, wherein the transmission element includes an operating element that generates a magnetic field that actuates the reed switch or is detected by the Hall element.

[0061] In another possible design of the gas densitometer, it is provided that a contact device assigned to the at least one switching element or a plurality of contact devices assigned to different switching elements are electrically connected to one or more switching elements via a cable connection or a conductor path on a circuit board. In this case, a contact device can include two single contacts, each of which is connected to a switching element and is electrically connected to each other when the switching element is actuated and is not electrically connected to each other when the switching element is not actuated, or vice versa. It can also be provided that all contact devices are integrated into a common plug assembly and are accessible from outside the housing via the plug assembly, that is, electrical contact can be made in a simple manner. It can also be provided that a plurality of contact devices share a common single contact, which is connected to a plurality of switching elements. This can reduce the number of required single contacts.

[0062] The maximum extension and compression that the reference pleats can elastically perform is limited. This results in the gas density monitors of the prior art being able to perform accurate measurements only within a narrow pressure range, within which force balance can be established by the elastic compression and extension of the pleats.

[0063] In order to expand the possible measuring range in one or both directions, another possible embodiment of the gas densitometer provides for the gas densitometer to include at least one first spring element. In particular, the first spring element is disposed within the first housing and / or within the reference chamber and / or within the measuring chamber and / or is arranged substantially parallel to the longitudinal axis of the reference bellows. A first end section of the first spring element can be in direct or indirect mechanical contact with the isolation mechanism, and / or a second end section of the first spring element can be in direct or indirect mechanical contact with a third inner wall section of the first housing.

[0064] The resulting advantage is that the measuring range of the gas density meter can be expanded toward lower or higher pressures. Without the spring element and its force, the measuring range of the gas density meter would be limited to a narrow range of a few bar, since the reference bellows can only elastically expand or compress to a limited extent. Increasing the spring force can reduce the expansion or compression of the reference bellows, or the accompanying volume change of the reference chamber, and the resulting pressure change in the reference chamber, which is required to achieve force equilibrium with the existing pressure in the measuring chamber.

[0065] This means that, in addition to the pressure, spring forces act on one or both surfaces of the isolating element. These spring forces depend along a straight line on the compression of the spring element. The translation of the isolating element required for force equilibrium and the accompanying volume change of the reference chamber can be reduced by compressing one spring more and more, thereby exerting increasingly greater spring forces on the isolating element.

[0066] If, for example, the spring element is arranged so that it presses against the isolating means from above, it will be compressed increasingly more as the pressure in the upper measuring chamber drops. The pressure of the reference gas not only counteracts the decreasing pressure of the insulating gas, but also the increasing spring force. The spring element is dimensioned so that, with a constant maximum bellows expansion and a defined minimum insulating gas pressure, a force balance is always achieved.

[0067] In order to achieve the aforementioned advantages for various installation situations, another possible embodiment of the gas density meter provides for the spring element to be designed as a coil spring, leaf spring, balance spring, or helical torsion spring. Furthermore, it can be provided that the spring element is designed as a bellows, spiral spring, or spring sleeve. The spring element or parts of the spring element can be made of a metallic material or a plastic.

[0068] In another possible design of the gas densitometer, an end section of the spring element is a region of the body of the spring element, which is located near a point of the spring element at which force or mechanical stress is introduced into the spring element or transmitted from the spring element to another body.

[0069] In another possible design of the gas densitometer, provision is made for direct or indirect mechanical contact to be established by clamping a spring element between the isolating mechanism and the third inner wall section, with the corresponding end section of the spring element being in mechanical contact with the isolating mechanism or the second inner wall section of the first housing. Provision can also be made for the isolating mechanism to include a spring element receptacle designed to secure the spring element in a set position and / or to prevent the spring element from rotating and / or slipping relative to the isolating mechanism. Furthermore, a spring element receptacle can also be provided on the third inner wall section. The spring element receptacle on the isolating mechanism and / or on the third inner wall section secures the spring element in a predetermined location and / or position and can, in particular, include a groove into which an end section of the spring element can be inserted or engaged. Provision can also be made for the direct or indirect contact to be achieved by a non-detachable connection, such as a welded connection, a soldered connection, an adhesive connection, or a clamped connection. In such a clamping connection, in which the spring element is clamped, ie prestressed, between the insulating means and the inner wall section, the function and effect of the spring element can be designed particularly precisely and the spring element is simultaneously fixed in its position against shaking, vibration and slipping.

[0070] In another possible embodiment of the gas density meter, the housing further includes at least a second housing chamber, wherein a connecting opening is provided in an intermediate wall between the at least two housing chambers, and the transfer element extends from the first housing chamber through the connecting opening into the second housing chamber. The housing chambers are sealed relative to one another, and the transfer element has a cross-sectional area that is smaller than the cross-sectional area of ​​the first bellows.

[0071] The resulting advantage is that components of the gas density meter that do not need to be located in the first housing can be located in the second housing. These components do not come into contact with the gas from the gas chamber. This significantly reduces the requirements for the components' resistance to media, and the gas density meter can be manufactured more simply and economically. Furthermore, this makes the structure simpler and more modular.

[0072] If the transmission element is guided out of the first housing, that is, out of the measuring chamber, either by means of a seal or surrounded by an isolating bellows, the insulating gas from the gas chamber can no longer be pressed against the entire surface of the isolating element in the measuring chamber. The resulting pressure is therefore lower than if this pressure were to act on the entire surface. However, the reference gas within the reference chamber can be pressed against the entire surface of the isolating element, at least within the diameter of the reference bellows. This means that, in the force balance, a lower pressure is generated in the reference chamber than in the measuring chamber.

[0073] This has the advantage that in the event of a fault, such as a leak between the measuring chamber and the reference chamber, and the resulting slow pressure equalization between the chambers, a pressure increase in the reference chamber occurs. This pressure increase, however, causes a translation of the isolation mechanism, which is equivalent to a pressure drop in the measuring chamber in a fault-free situation. Combined with the expansion of the measuring range to lower pressures achieved using the spring element, this results in the insulating gas pressure dropping below the pressure in the reference chamber from a specific point onward. However, the gas volume in the reference chamber, the ratio of the free surface against which the insulating gas and reference gas press, and the spring strength of the spring element can be advantageously coordinated so that the pressure in the reference chamber is lower than the pressure in the measuring chamber, at least when the measuring chamber pressure corresponds to the normal operating pressure of the device.

[0074] In another possible embodiment of the gas density meter, the second housing is connected to the environment in a gas-permeable manner or is also sealed relative to the environment. The seal between the first housing and the second housing prevents gas from escaping from the gas chamber into the second housing and / or the environment.

[0075] Another possible design of the gas densitometer provides for the connecting openings between the housings to be formed by direct through-holes in the intermediate wall. This simplifies the manufacturability of the gas densitometer. However, the connecting openings can also be designed as connecting lines comprising multiple segments with different extension directions. All parts of the housing that adjoin at least one of the housings and prevent a gas-permeable connection between the housings can be considered intermediate walls.

[0076] In accordance with the second aspect of the present invention, an advantageous embodiment provides that, by means of the ratio of the cross-sectional area of ​​the transmission element to the cross-sectional area of ​​the separating means, or by means of the ratio of the cross-sectional area of ​​the transmission element to the cross-sectional area of ​​the reference bellows, it is predetermined that the pressure in the reference chamber and the pressure outside the reference chamber, i.e., the pressure inside the measuring chamber, act on surfaces of different sizes perpendicular to the longitudinal axis of the bellows. For example, it is provided that the pressure in the reference chamber acts on a larger surface perpendicular to the longitudinal axis of the bellows than the pressure in the measuring chamber. This allows the pressure ratio in the two chambers to be adjusted in a simple and reliable manner according to preset values ​​for a specific application.

[0077] In accordance with the third aspect of the present invention, an advantageous embodiment provides that the ratio of the cross-sectional area of ​​the reference fold to the cross-sectional area of ​​the measuring fold is used to predetermine that the pressure in the reference chamber and the pressure within the measuring chamber act on surfaces of different sizes perpendicular to the longitudinal axis of at least one fold. For example, it is provided that the pressure in the reference chamber acts on a larger surface perpendicular to the longitudinal axis of the fold than the pressure in the measuring chamber. For example, the folds are arranged collinearly. This allows the pressure ratio in the two chambers to be adjusted in a simple and reliable manner according to preset values ​​for a specific application.

[0078] In another possible design of a gas densitometer, the first and second housings are sealed relative to one another by providing a sealing element that is sealingly disposed between the connecting opening and the transfer element extending therethrough. The sealing element can be a plastic seal, such as an O-ring, an X-ring, another sealing ring, or a plain bearing. Using a seal has the advantage that it can be easily integrated and requires a small number of components.

[0079] In another possible design of a gas densitometer, the first and second housing chambers are sealed relative to one another by providing an additional bellows that is directly or indirectly connected to the separating means and the intermediate wall section such that the additional bellows at least partially surrounds the transmission element, and the connecting opening between the housing chambers is located within the intermediate wall section. Such a bellows can be referred to as a separating bellows, because in this arrangement the first and second housing chambers are separated and sealed from one another by the separating bellows. This design has the advantage of ensuring a particularly high degree of sealing of the first housing chamber against the environment and against the other housing chambers. Furthermore, this solution is less susceptible to wear than seals in the connecting openings, which are subject to significant static and sliding friction on the transmission element.

[0080] In accordance with the second aspect of the present invention, one possible embodiment provides for a separating bellows to be provided for isolating and sealing the housing chambers relative to one another, the separating bellows having a smaller diameter than the reference bellows. The separating bellows can thus also be used to adjust the pressure in the reference chamber and the pressure in the measuring chamber to act on surfaces of different sizes perpendicular to the longitudinal axis of the reference bellows, as already explained in the previous paragraph regarding the cross-sectional area of ​​the transmission device.

[0081] Another possible embodiment of the gas densitometer provides for the reference bellows and / or the measuring bellows and / or the separating bellows to be designed as a flexible body. In particular, within the scope of the present invention and in its refinements, each bellows can be designed in the form of a bellows, a bellows, a diaphragm bellows, a bellows hose, or the like. The bellows can be made of a metallic material such as steel, high-grade steel, brass, or aluminum, or of a plastic or composite material. Furthermore, the bellows can have a cylindrical shape and thus a circular cross-section or other cross-sectional shape.

[0082] For all pleated bags within the present context, the area of ​​the pleated bag wall located near the open end of the pleated bag is understood to be the end section of the pleated bag. This area particularly includes the end edges of the pleated bag. The geometry of the pleated bag shows that each pleated bag has two end sections, which are located at opposite ends of the pleated bag.

[0083] Furthermore, the design features of the airtight connection, as already described in the previous paragraph with reference to the connection between the end section of the bellows and the separating means or the inner wall section, can also be transferred to the connection between the end section of the insulating bellows and the separating means or the intermediate wall section.

[0084] In this case, the isolating fold, the reference fold and / or the measuring fold in each embodiment can have different lengths, different diameters, different shapes and / or be made of different materials or can be identical in one or more of these aspects.

[0085] In another possible embodiment of the gas densitometer, the constant amount of reference gas in the reference chamber is determined such that, when the gas densitometer is loaded with a first pressure, which can be assigned to the normal operating state of the gas chamber, a second pressure is generated in the reference chamber in the equilibrium of all acting pressures, mechanical stresses, and / or spring forces, which is lower than the first pressure. The various selected surfaces perpendicular to the longitudinal axis of the reference bellows, as described in the preceding paragraphs, on which the pressures in the reference chamber and the pressures in the measuring chamber can act, have a decisive influence on this.

[0086] Loading the gas densitometer means that the pressure present in the first housing according to the second aspect of the invention or in the measuring bellows according to the third aspect of the invention is introduced into the measuring chamber of the gas densitometer via the coupling.

[0087] The advantage created by the described pressure difference is that if a fault in the gas densitometer causes a gas-permeable connection between the reference chamber and the measuring chamber, the pressure in the reference chamber increases rather than decreases. This causes the ratio of the forces acting on the isolating mechanism or the reference bellows to change, causing the bellows to move or change in volume, which, in the absence of a fault, would only be caused by a decrease in the load pressure in the measuring chamber. The movement of the first bellows is transmitted to the switching and / or monitoring unit via the transmission element. The fault thus causes an effect on the switching and / or monitoring unit that is interpreted as a decrease in the load pressure, i.e., the pressure in the gas chamber. This allows the operator of the gas chamber to notice the fault more quickly and identify the fault in the gas densitometer more quickly.

[0088] In another possible design of a gas densitometer, the conversion and / or monitoring unit includes a display device with an indicator element and an operating mechanism. A transmission element is directly or indirectly operatively connected to the operating mechanism, and movement of the transmission element directly or indirectly causes movement of the indicator element via the operating mechanism. This has the advantage that the measured and / or monitored gas density can be read directly on the gas densitometer.

[0089] Another possible embodiment of the gas densitometer provides for the display device to include a scale and an observation window. The display device can be configured such that the observation window forms a section of the exterior of the housing and allows viewing of the scale and pointer element. The pointer element can be configured to move relative to the scale and / or the housing. This movement can particularly be a rotation about an axis of rotation that extends substantially perpendicular to or parallel to the plane of the scale surface.

[0090] In another possible embodiment of the gas densitometer, it is provided that the operating mechanism is provided for converting a movement of the transmission element into a controlled movement, in particular a rotation, of the pointer element.

[0091] In another possible embodiment of the gas densitometer, the at least one switching element and the transmission element are arranged and can be directly or indirectly operatively connected to one another in such a way that the switching element is actuated directly or indirectly via the transmission element when the gas densitometer is acted upon by a pressure equal to or greater than a limiting pressure. When the acted upon pressure drops below the limiting pressure, the switching element is no longer actuated directly or indirectly via the transmission element.

[0092] In this context, the limit pressure can also be referred to as the switching point of the gas densitometer. This arrangement according to the present invention has the advantage that the switching element is always actuated when the applied pressure is greater than the limit pressure, i.e., greater than the switching point. A fault in the electrical connection between the switching element and the electrical contact device, or, as is often the case in practice, in an external cable connected to the gas densitometer, has the same effect on signal transmission to the external monitoring and / or control device as a drop in the applied pressure below the limit pressure. This allows for immediate identification of such faults.

[0093] In another possible design of a gas densitometer, the gas densitometer includes a second spring element, wherein the first spring element and the second spring element directly or indirectly apply a spring force to the isolation mechanism. The second spring element is, for example, arranged inside the first housing and / or inside the reference chamber and / or inside the measuring chamber and / or is arranged to be at least substantially parallel to the longitudinal axis of the first bellows. The first end section of the second spring element can be in direct or indirect mechanical contact with the isolation mechanism, and / or the second end section of the second spring element can be in direct or indirect mechanical contact with the fourth inner wall section of the first housing. With the help of this second spring element, a spring force can be generated on one or both surfaces of the isolation mechanism using the previously described effects and advantages of the first spring element.

[0094] In another possible design of the gas densitometer, all or part of the features of the first spring element, the third inner wall section, and the mechanical contact between the end section of the first spring element and the other elements described in the previous paragraph apply similarly to the second spring element, the fourth inner wall section, and the mechanical contact between the end section of the second spring element and the other elements.

[0095] In another possible embodiment of the gas densitometer, the first and second spring elements are arranged so that they exert forces on the isolating means in essentially opposite directions. Furthermore, the first and second spring elements can be prestressed in their arrangement. This has the advantage that the gas densitometer exhibits reduced hysteresis during measurement operation and, as already explained in the preceding paragraph with respect to the first spring element for one direction, the measuring range can be expanded simultaneously towards both low and high pressures.

[0096] In another possible design of the gas densitometer, the housing is a multi-part housing, wherein at least the first housing chamber is arranged in a first housing part and at least one further housing chamber is arranged in a second housing part. The first and second housing parts are directly or indirectly connected to one another and / or can be rotated relative to one another about at least one axis of rotation. This has the advantage that the gas densitometer can be constructed in a modular manner and manufactured economically. In combination with a display device or a contact device arranged on or in the second housing part, the advantage resulting from the rotatability is that the orientation of the display device or the accessibility of the contact device can be adapted to different installation situations of the gas densitometer and thus optimized.

[0097] Another possible design of the gas densitometer provides for at least the second housing chamber to be arranged in the second housing part. Furthermore, it can be provided that the housing parts are directly or indirectly connected to one another, either releasably or non-releasably, for example by welding, screwing, plugging, snapping, bayonet fitting, or clamping. Using two housing parts and distributing the housing chambers between them offers the advantage that the components of the gas densitometer can be manufactured more simply and economically, and the gas densitometer is designed to be modular, thereby making it easier to replace individual components in the event of a malfunction, for example.

[0098] Another possible design of the gas densitometer provides that the at least one rotational axis is arranged parallel to and / or coincides with the longitudinal axis and / or the axis of symmetry of the main body of the housing part. Furthermore, it can be provided that the housing comprises at least two housing parts and a housing coupling part, wherein the two housing parts are connected to the housing coupling part on two different surfaces thereof and are rotatable about different rotational axes predetermined by the orientation of the respective surfaces of the housing coupling part. This allows the gas densitometer to be particularly flexibly adapted to specific installation situations and easily oriented.

[0099] In another possible embodiment of the gas densitometer, it is provided that the first housing part and the second housing part have an essentially cylindrical form, and that the axis of symmetry A of the first housing part extends at least essentially parallel and / or at least essentially coincides with the axis of symmetry B of the second housing part. This allows for a particularly simple to manufacture, modular, and compact design of the gas densitometer that can be manufactured economically.

[0100] In this context, the axis of symmetry relates to the symmetry of the cylindrical base body of the housing parts. Possible disruptions of symmetry due to formed or added parts such as connectors or electrical contacts or cuts on the body surface are not taken into account.

[0101] In another possible design of the gas densitometer, the constant amount of reference gas in the reference chamber is determined as follows, i.e., when the gas densitometer is loaded with a first pressure that can be configured for the normal operating state of the gas chamber, a second pressure is generated in the reference chamber in the balance of all acting pressures, mechanical stresses and / or spring forces, which second pressure is lower than the limit pressure. The limit pressure is lower than the first pressure. In particular, the second pressure can be at least 0.1 bar, 0.15 bar or 0.2 bar lower than the limit pressure. This design further improves the advantages described in the above-mentioned improvement scheme for the gas densitometer, i.e., it is easier to identify a fault on the gas densitometer, which leads to a gas-permeable connection between the reference chamber and the first housing. This design ensures that the pressure increase in the reference chamber caused by the fault leads to an effect on the conversion and / or monitoring unit, which is equivalent to the loaded pressure falling below the limit pressure.

[0102] In another possible embodiment of the gas density meter, the conversion and / or monitoring unit includes a display device having a pointer element and a pointer detection device, the pointer detection device being configured to detect the position or location of the pointer and convert it into an electrical signal. The conversion and / or monitoring unit includes either a signal contact device electrically connected to the pointer detection device and accessible from outside the housing, or a radio device electrically connected to the pointer detection device and converting the electrical signal of the pointer detection device into a radio signal. This has the advantage that the gas density can be measured not only by reading the display device or receiving a limit value signal, but also by continuously evaluating the gas density measurement via an electrical connection to the signal contact device or via a radio connection.

[0103] In another possible design of a gas density meter, the pointer detection device includes one or more Hall sensors and electronic evaluation equipment, wherein the pointer is directly or indirectly connected to a magnet. Movement of the pointer causes movement of the magnet and, therefore, a change in the magnetic field, which is detected by the pointer detection device and converted into an electrical signal, particularly an analog or digital signal.

[0104] In another possible embodiment of the gas density meter, the electrical signal is an analog current signal, for example a 4 mA to 20 mA signal, or a voltage signal, for example a 0 to 10 V signal, or a digital signal, in particular according to common industrial standards.

[0105] Another possible design of the gas density meter provides that the radio module generates radio signals according to common radio standards and / or includes a power supply and / or an antenna assembly. The antenna assembly can be located in the housing or attached to the edge of a housing surface section. The power supply can particularly include a battery. The battery is externally accessible and replaceable in a battery compartment on the housing. This eliminates the need for expensive cables and facilitates remote access.

[0106] Due to the use of batteries, the gas density meter can be operated largely autonomously and can be easily maintained by the user.

[0107] In another possible design of a gas densitometer, the connector comprises: a process interface for connecting the connector to the gas chamber; a measuring interface via which the connector is connected to the gas densitometer; a shut-off device; an access interface; and a pipeline system that connects the access interface, the process interface, the measuring interface, and the shut-off device to one another in a gas-permeable manner. The shut-off device is arranged in the pipeline system so that the connection between the process interface and the measuring interface, as well as the connection between the process interface and the access interface, can be shut off by the shut-off device, wherein the measuring interface and the access interface remain gas-permeable to one another. The resulting advantage is that the gas-permeable connection between the gas densitometer and the gas chamber can first be shut off by means of the shut-off device, and then the gas densitometer can be loaded with, for example, a test gas or a test pressure via the access interface and its function can be checked in this way. The gas densitometer does not have to be removed from the gas chamber for this check.

[0108] In another possible design of the gas densitometer, the process interface is configured as an interface for mounting the gas densitometer on the gas chamber. Such an interface can be realized, for example, by an internal or external thread, by a flange joint or by a plug coupling. The measuring interface can be provided for gas-permeable connection to the first shell of the gas densitometer and in particular for direct or indirect connection to the gas densitometer. Such a connection can be, for example, a welding connection, a brazing connection, a clamping connection, a locking connection, an adhesive connection or a threaded connection. The access interface can be configured as an internal or external thread, a flange joint, a plug joint or a coupling using a lock nut. The access interface can also be provided with a self-sealing valve so that when the connection to the corresponding coupling that opens the self-sealing valve is loosened, the connection to the pipeline system is cut off.

[0109] Another possible design of the gas density meter provides for the coupling to be designed as a one-piece component, and for the pipeline system to be integrated into the coupling. The one-piece design of the coupling results in a particularly high leak-tightness and high robustness against vibrations and mechanical shocks. The coupling and its components can be made of metallic materials such as aluminum, copper, brass, steel, or high-grade steel.

[0110] Another possible design of a gas density meter provides for a shutoff device that can or must be opened and closed using a tool, in particular a wrench, and includes a valve having a sealing body that has a conical shape. The valve can also be designed in the form of a ball valve. The requirement to use a tool to operate the valve prevents unauthorized personnel from easily operating the valve.

[0111] In another possible embodiment of the gas densitometer, it is provided that the first housing surrounds at least the reference bellows or reference chamber, the measuring chamber, the separating means and at least partially the transmission element, while the second housing surrounds the conversion and / or monitoring unit.

[0112] In another possible embodiment of the gas densitometer, the first housing additionally surrounds the first spring element, the second spring element, and / or the separating bellows, while the second housing additionally surrounds the at least one switching element. However, it is also possible for at least one of the spring elements to be arranged within the second housing and to exert a force there directly or indirectly on the transmission element. In particular, a spring element can be arranged in the second housing substantially parallel to the longitudinal axis of the reference bellows.

[0113] The two aforementioned embodiments result in the advantage that the gas density meter can be produced particularly easily, can be manufactured economically, and has a compact design.

[0114] In another possible design scheme of the second aspect of the present invention, it is provided that one or more inlets are provided on the reference chamber, and a monitoring display or monitoring sensor is connected to the inlet from outside the housing, or a monitoring sensor arranged inside the housing, in particular inside the measuring chamber, is connected to the reference chamber via a line on the inlet. The monitoring display can be, for example, a mechanical pressure gauge, in particular a micro pressure gauge. The monitoring sensor can in particular be an electronic measurement value converter. The line can in particular be a soft line, a hose or a soft capillary line. Such a monitoring display or monitoring sensor can be advantageously used to monitor the pressure and / or gas density in the reference chamber and thereby make the sealing of the reference chamber checkable. The electronic monitoring sensor can be connected to the monitoring contact device via an electric wire. A connection via which the electrical measurement signal of the monitoring sensor can be acquired from outside the housing.

[0115] In any embodiment or development of the gas densitometer, electrical lines to be led from one housing chamber to another or out of the housing can be led, for example, through gas-tight plated-through holes. Such plated-through holes can in particular be vitrified plated-through holes.

[0116] The individually described embodiments and features of the aspects of the invention and the advantageous embodiments of the gas density meter are not limited in whole or in part to one aspect of the invention or one embodiment of one aspect; the invention also includes all resulting combinations. BRIEF DESCRIPTION OF THE DRAWINGS

[0117] Possible exemplary embodiments of the present invention are explained in detail below with reference to the accompanying drawings.

[0118] in:

[0119] Figure 1 schematically shows a cross-sectional view of a gas chamber on which a gas density meter is mounted;

[0120] Figure 2A and 2B Schematic cross-sectional views of different designs of gas density meters;

[0121] Figure 3A and 3B Schematic cross-sectional views of corresponding parts of different designs of gas densitometers in the region of the conversion and / or monitoring unit;

[0122] Figure 3C and 3D Schematic cross-sectional views of different embodiments of a gas density meter with a conversion and / or monitoring unit;

[0123] Figures 4A to 4E Schematic cross-sectional views of different designs of a gas density meter with two spring elements;

[0124] Figure 5A and 5B Schematic cross-sectional views of different spring element receptacles;

[0125] Figure 6A and 6B Schematic cross-sectional views of different designs of a gas density meter having two housing chambers;

[0126] Figure 7 A cross-sectional view schematically shows a portion of a gas density meter having a display device;

[0127] Figure 8A and 8B Schematically shows a cross-sectional view and a side view of a gas density meter having two housing parts;

[0128] Figure 9A and 9B A perspective view schematically shows a gas densitometer having two cylindrical housing parts;

[0129] Figure 10A partial cross-sectional view schematically showing a gas density meter having a pointer detection device;

[0130] Figure 11 A circuit diagram schematically showing a connector for a gas density meter;

[0131] Figures 12A to 12D Schematic cross-sectional views of different embodiments of a gas density meter having two spring elements and a measuring bellows;

[0132] Figure 13A and 13B Schematically showing a cross-sectional view of a gas density meter when loaded with different pressures;

[0133] Figure 14 schematically shows a cross-sectional view of a gas density meter;

[0134] Figure 15 A cross-sectional view schematically showing a portion of a gas density meter;

[0135] Figure 16A and 16B Schematically showing views of the isolation mechanism from both sides;

[0136] Figures 17A to 17C Schematic cross-sectional view showing different designs of the folded bladder wall.

[0137] In all the figures, mutually corresponding parts are provided with the same reference numerals. DETAILED DESCRIPTION

[0138] Figure 1 A cross-sectional view of a gas chamber 1 is shown, on which a gas density meter 100 , 200 is mounted.

[0139] The gas chamber 1 accommodates, for example, an electrical circuit breaker 154 and is filled, in a manner not shown in detail, with an insulating gas, for example sulfur hexafluoride (abbreviation: SF 6 ), which is provided for extinguishing switching arcs occurring between the contacts of the circuit breaker 154 .

[0140] A gas chamber 1 filled with insulating gas is characterized by a defined pressure value that can be assigned to the normal operating state of the gas chamber 1. In order to detect any leakage or emission of insulating gas at an early stage, the density of the insulating gas in the gas chamber 1 is monitored by means of a gas density meter 100, 200, for example, designed as a gas density monitor, and a corresponding limit value signal is triggered if the density falls below a defined limit value that is less than a predefined nominal pressure.

[0141] Figure 2AA cross-sectional view of a possible embodiment of a gas density meter 100 is shown, which includes a housing 102, a first housing 103, a coupling 104, a first bellows 105, a separating element 108, a transmission element 109, and a switching and / or monitoring unit 110. A first end section 106A of the bellows 105 is connected to a first inner wall section 107 of the first housing 103. A second end section 106B of the bellows 105 is connected to or forms the separating element 108. These connections form a reference chamber 111 filled with a reference gas 112.

[0142] The insulating gas is introduced from the gas space 1 into the measuring space 168 via the coupling 104 . The measuring space 168 is formed by the first housing 103 .

[0143] The insulating gas in the measuring chamber 168 exerts pressure on one surface of the isolating means 108. The reference gas 112 enclosed in the reference chamber 111, that is, in the bellows 105, in turn exerts pressure on the opposite surface of the isolating means 108. The system strives for a state in which a balance of forces exists.

[0144] The pressure on one surface of the isolation means 108 is directly determined by the pressure of the introduced insulating gas, while the pressure on the opposite side of the isolation means 108 can be varied by the reference gas 112 by changing the volume of the reference chamber 111. In this case, the bellows 105 compresses or expands under the influence of the pressure on the surface of the isolation means 108 until a force equilibrium is reached.

[0145] The translational movement of the separating device 108 during the compression or expansion of the bellows 105 is mechanically transmitted via a transmission element 109 to a switching and / or monitoring unit 110 .

[0146] If the pressure of the insulating gas from the gas chamber 1 decreases, the bellows 105 expands, causing the separating member 108 to move upward, for example. Conversely, if the pressure of the insulating gas from the gas chamber 1 increases, the bellows 105 is compressed, causing the separating member 108 to move downward.

[0147] If the temperature of the insulating gas in the gas chamber 1 changes, this always leads to a pressure increase, since the gas chamber 1 is usually a gas-tight container with a constant volume. Likewise, cooling of the insulating gas in the gas chamber 1 leads to a pressure drop.

[0148] However, these pressure changes do not correspond to changes in gas density, that is, do not correspond to gains or losses of gas, which should nevertheless be monitored. Therefore, these pressure changes caused by temperature changes must be compensated.

[0149] This is achieved by enclosing reference gas 112 in reference chamber 111. This reference gas is in thermal contact with gas chamber 1 and the insulating gas via the walls of bellows 105 and the entire housing 102. When the temperature of both the insulating gas and reference gas 112 rises, that is, when there is thermal equilibrium between measuring chamber 168 and reference chamber 111, the pressure in reference chamber 111 rises to the same degree as the pressure in measuring chamber 168. Consequently, temperature-induced pressure changes do not result in pressure changes on the surface of isolation member 108, and isolation member 108 does not undergo translational movement.

[0150] A prerequisite for precise temperature compensation is that the reference gas 112 experiences the same pressure increase as the insulating gas in the event of a temperature change. Therefore, a gas that is also present in the gas chamber 1 is used as the reference gas 112 in a particularly precise manner.

[0151] Figure 2B A sectional view of a further possible embodiment of a gas density meter 200 is shown, which has a housing 202 , a first housing chamber 203 , a coupling 204 , a first bellows 205 , a second bellows 225 , a separating device 208 , a transmission element 209 and a switching and / or monitoring unit 210 .

[0152] The first end section 206A of the folded capsule 205 is connected to the inner wall section 207 of the first housing 203. The second end section 206B of the folded capsule 205 is connected to or forms the isolation means 208. Through these connections, the folded capsule 205 forms a reference chamber 211 filled with a reference gas 212.

[0153] The first end section 257A of the folded bag 225 is connected to the inner wall section 218 of the first housing 203 and the coupling 204. The second end section 257B of the folded bag 225 is connected to or forms the separating means 208. Through these connections, the folded bag 225 forms a measuring chamber 268, which is filled with gas that flows into the measuring chamber 268 via the coupling.

[0154] That is to say, the measuring chamber 268 is not formed by the first housing 203, but by the bellows 225. Therefore, the insulating gas from the gas chamber 1 is Figure 2A Unlike the embodiment shown in FIG, it flows into a bellows 225, which is arranged in the housing 203. The gas contained in the bellows 225 presses against the isolation means 208 from one side, and the reference gas 212 in the reference chamber 211 presses against the isolation means 208 from the other side, so that a force balance is produced in a non-fault situation.

[0155] Figure 3A and 3BPartial cross-sectional views of possible embodiments of gas densitometers 100 and 200 are shown, respectively, wherein the structure and function of the gas densitometers 100 and 200 may correspond to those in FIG. Figure 2A 、 2B The structure shown in Figure 2A 、 2B The functions described in .

[0156] The switching and / or monitoring unit 110 , 210 coupled to the transmission element 109 , 209 comprises a switching element 113 , 213 and a contact arrangement 114 , 214 .

[0157] exist Figure 3A In the illustrated embodiment, the switching and / or monitoring unit 110, 210 is designed such that when the insulating gas pressure in the housing chamber 1 and thus in the measuring chamber 168, 268 drops, the transmission element 109, 209 moves upward and, when the pressure falls below a predetermined switching pressure, acts on the switching element 113, 213, causing the switching element to close and applying an electrical signal to the contact arrangement 114, 214. However, if the insulating gas pressure in the housing chamber 1 and thus in the measuring chamber 168, 268 is sufficiently high and does not fall below the switching pressure, the switching element 113, 213 is in the open state and no electrical signal is applied to the contact arrangement 114, 214.

[0158] exist Figure 3B In the exemplary embodiment shown, a plurality of switch elements 113, 213 are also arranged on a support element 148, 248. The transmission element 109, 209 comprises an operating element 149, 249 having a plurality of pushbutton units 150, 250, each of which is assigned to a switch element 113, 213.

[0159] In the illustrated embodiment, the switching and / or monitoring unit 110, 210 is designed such that, when the pressure of the insulating gas in the housing cavity 1 and therefore in the measuring chamber 168, 268 is sufficient, the transfer element 109, 209 together with the operating element 149, 249 is located in a deep position and the button unit 150, 250 is operated and thus the switching element 113, 213 is continuously connected.

[0160] In the event of a drop in the insulating gas pressure in the housing cavity 1 and therefore in the measuring chambers 168 , 268 , the transmission elements 109 , 209 together with the operating elements 149 , 249 and the key units 150 , 250 move upwards, and the switching elements 113 , 213 are disconnected when the pressure falls below a respectively predetermined and configured switching pressure.

[0161] The contact devices 114 , 214 of the switching elements 113 , 213 are integrated into the plug assembly 151 , 251 and are accessible from outside the housing 102 and can be coupled to the external plug 152 , 252 .

[0162] Plugs 152, 252 are, for example, components of an external monitoring and / or display unit (not shown in detail), with the help of which the switching states of the individual switching elements 113, 213 can be electrically measured or determined via plugs 152, 252 and corresponding information can be issued and / or corresponding measures can be taken when the pressure inside the gas chamber 1 and therefore inside the measuring chamber 168, 268 falls below, for example, the information is transmitted to headquarters or maintenance and / or operating personnel.

[0163] Figure 3C and 3D The cross-sectional views of various exemplary embodiments of a gas density meter 200 are shown, which has a conversion and / or monitoring unit 210, wherein the structure and function of the gas density meter 200 corresponds in particular to Figure 2B The structure shown and Figure 2B Description of the function.

[0164] exist Figure 3C In the embodiment shown, the conversion and / or monitoring unit 210 is based on Figure 3B Description composition.

[0165] exist Figure 3D In the illustrated embodiment, the switching and / or monitoring unit 210 includes a magnetic element 269 fastened to the isolation mechanism 208 (which is arranged between the bellows 205, 225) and two magnetic field sensors 256. The isolation mechanism 208 is fastened to the housing 202 on the side opposite the magnetic element 269 and having the pivotable suspension point 267. Therefore, under different pressure conditions within the bellows 205, 225, the isolation mechanism 208 moves, and the relative position of the magnetic element 269 relative to the magnetic field sensors 256 changes accordingly. This allows different states, in particular different positions of the isolation mechanism 208 and, consequently, different pressure or density values ​​(which must be present in the measuring chamber 268), to be detected and outputted by the switching and / or monitoring unit 210.

[0166] exist Figure 4A 、 4B4C and 4D show cross-sectional views of various embodiments of a gas density meter 100 having a housing 102, a first housing 103, a coupling 104, a first bellows 105, a separating element 108, a transmission element 109, a switching and / or monitoring unit 110, and a first spring element 115. An end section 117 of the first spring element 115 is connected to the separating element 108 and to a second inner wall section 118. Furthermore, the longitudinal axis 116 or center axis of the first bellows 110 is shown. In the illustrated embodiment, the first spring element 115 is oriented at least substantially parallel to and / or coaxially around the longitudinal axis 116. Furthermore, a second spring element 131 is provided, the spring force of which acts in opposition to the spring force of the first spring element 115.

[0167] Spring elements 115, 131 enable spring forces to act on one or both surfaces of the isolating element in addition to the gas pressure. These spring forces depend along a straight line on the compression of the respective spring elements 115, 131. The translation of isolating element 108 required for force compensation and the resulting change in volume of reference chamber 111 can be reduced by increasing the compression of spring elements 115, 131 and thereby exerting increasing spring forces on isolating element 108.

[0168] If, for example, the spring elements 115 and 131 are configured so that they press against the isolating means 108 from above, they are compressed increasingly more as the pressure in the upper measuring chamber 168 decreases. This means that the pressure of the reference gas 112 overcomes not only the decreasing pressure of the insulating gas but also the increasing spring force. The respective spring elements 115 and 131 are dimensioned so that a force balance is always achieved, even with a constant maximum expansion of the respective bellows 105 and 125 and a defined minimum insulating gas pressure.

[0169] exist Figure 4A In the embodiment, the second spring element 131 is arranged inside the first housing 103 on the side of the separating means 108 opposite the first bellows 105 . The first spring element 115 is arranged inside the first bellows 105 .

[0170] exist Figure 4B In the embodiment, the first spring element 115 is arranged inside the reference chamber 111 and coaxially surrounds the longitudinal axis 116 of the first bellows 105. The second spring element 131 is arranged inside the first housing 103 on the side of the separating means 108 opposite to the first bellows 105 and coaxially surrounds the transmission element 109. The functions of the spring elements 115 and 131 correspond to Figure 4A The function of the spring elements 115 , 131 is shown.

[0171] exist Figure 4CIn the embodiment, the first spring element 115 is arranged inside the first shell cavity 103 and coaxially surrounds the first folded bag 105. The arrangement structure of the second spring element 131 corresponds to the arrangement structure of the spring element in Figure 4B The function of the spring elements 115, 131 corresponds to Figure 4A The function of the spring elements 115 , 131 is shown.

[0172] Figure 4D The illustrated embodiment of the gas density meter 100 comprises a first bellows 105 and a second bellows 125 forming a reference chamber 111, which are arranged together within the first housing 103 and fastened to the separating means 108. The first housing 103 forms the measuring chamber 168 in this case.

[0173] The switching and / or monitoring unit 110 is arranged in the second housing 119 , wherein the transmission element 109 leads to the switching and / or monitoring unit 110 through a connecting opening 121 in the intermediate wall 120 .

[0174] The two spring elements 115 , 131 are each arranged coaxially with the respectively associated bellows 105 , 125 within these bellows.

[0175] Figure 4E The illustrated embodiment of the gas density meter 100 also comprises a first bellows 105 and a second bellows 125 forming a reference chamber 111, which are jointly arranged within the first housing 103 and fastened to the separating means 108. The first housing 103 forms the measuring chamber 168 in this case.

[0176] and Figure 4D The embodiment shown differs in that the first spring element 115 is arranged inside the first housing 103 and coaxially surrounds the first bellows 105 .

[0177] Figure 5A and 5B Two detailed sectional views show possible designs of spring element receptacles 153, 253 on the separating means 108, 208 and on the second inner wall section 118, 218 for accommodating the first spring element 115, 215 and the second spring element 131, 231. The spring element receptacles 153, 253 are each designed here as a circumferential groove and as a means of at least partially accommodating the last coil of the respective spring element 115, 215, 131, 231.

[0178] Figure 6A and 6BThe gas density meter 100 is shown in sectional views of different designs, which has a housing 102, a first housing chamber 103, a coupling 104, a first bellows 105, a separating mechanism 108, a transmission element 109, a conversion and / or monitoring unit 110, a second housing chamber 119, an intermediate wall 120 and a connecting opening 121.

[0179] In this case, the switching and / or monitoring unit 110 is arranged in the second housing 119 , wherein the transmission element 109 leads to the switching and / or monitoring unit 110 through a connecting opening 121 in the intermediate wall 120 .

[0180] exist Figure 6A In the exemplary embodiment shown, a sealing element 124 is additionally provided in the connecting opening 121 . The cross-sectional area 122 of the transfer element 109 is designed to be smaller than the cross-sectional area 123 of the first bellows 105 .

[0181] If, however, cross-sectional areas 122 and 123 are of equal size, the gas in measuring chamber 168 has no effective area on which to exert pressure on separating element 108. However, if cross-sectional area 122 is smaller, then there is such an area and, in the case of a force balance, a lower pressure prevails in reference chamber 111 than in measuring chamber 105.

[0182] If the transfer element 109 is sealed from the measuring chamber 168 by means of the sealing element 124, the result is that the insulating gas from the gas chamber 1 can no longer press against the entire surface of the isolating means 108 in the measuring chamber 168. The resulting pressure is therefore lower than if this pressure could press against the entire surface. However, the reference gas 112 inside the reference chamber 111 can press against the entire surface of the isolating means 108, at least within the diameter of the bellows 105. This means that, in the equilibrium of forces, a lower pressure is generated in the reference chamber 111 than in the measuring chamber 168.

[0183] This has the decisive advantage that in the event of a fault, such as a leak between measuring chamber 168 and reference chamber 111, and the resulting slow pressure equalization between the chambers, a pressure increase in reference chamber 111 occurs. However, this pressure increase leads to a translation of isolation element 108 that is equivalent to a pressure drop in measuring chamber 168 in the absence of a fault.

[0184] In conjunction with the expansion of the measuring range to lower pressures achieved by means of spring elements 115, 131, the inevitable consequence is that the pressure of the insulating gas drops below the pressure in reference chamber 111 from a certain point onward. However, the gas quantity in reference chamber 111, the ratio of the free surfaces against which insulating gas and reference gas 112 press, and the spring strengths of spring elements 115, 131 can advantageously be coordinated such that the pressure in reference chamber 111 is lower than the pressure in measuring chamber 168, at least when the measuring chamber pressure corresponds to the normal operating pressure of the device.

[0185] exist Figure 6B In the illustrated embodiment, a second fold 125 is provided, the cross-sectional area 126 of which is smaller than the cross-sectional area 123 of the first fold 105. The second fold 125 is connected to the partition 108 with a first end section 180A and to the intermediate wall 120 with a second end section 180B, and seals the second housing 119 from the first housing 103.

[0186] Figure 7 A sectional view of a detail of a gas densitometer 100 , 200 is shown, which is designed according to the gas densitometers 100 , 200 shown in FIGS. 2 to 6 .

[0187] Additionally, the switching and / or monitoring unit 110 comprises an operating mechanism 130 and a display device 128 having a pointer element 129. The arrows indicate that expansion or compression of the first bellows 105 leads to a change in the display, whereby pressure changes in the gas chamber 1 can be displayed in trouble-free operation.

[0188] This is also evident in a fault situation in which a leak between the measuring chamber 168, 268 and the reference chamber 111, 211 causes a movement of the isolating element 108, 208, as does a pressure drop in the gas chamber 1. This allows a fault to be identified. By comparing with other measuring points, it can be seen that there is actually no pressure drop in the gas chamber 1, and a fault in the gas density meter 100, 200 itself can be detected.

[0189] Figure 8A A cross-sectional view of a possible embodiment of a gas density meter 100 is shown. Figure 8B Show Figure 8A Side view of a gas density meter shown.

[0190] and Figure 6BUnlike the embodiment shown, the housing 102 comprises two housing parts 134, 135, wherein the first housing chamber 103 is constructed in the first housing part 134 and the second housing chamber 119 is constructed in the second housing part 135. The intermediate wall 120 is constructed as a double wall and comprises an upper wall of the first housing part 134 and a lower wall of the second housing part 135, wherein the connecting opening 121 extends through both walls. In addition, the gas density meter 100 is configured according to the embodiment of the present invention. Figure 6B Description composition.

[0191] The first housing part 134 has a smaller diameter than the second housing part 135 , wherein the axes of symmetry A, B of the two housing parts 134 , 135 coincide.

[0192] Figure 9A and 9B The figures show perspective views of various exemplary embodiments of a gas densitometer 100 , which has two cylindrical housing parts 134 , 135 .

[0193] Here, the rotation axes of the housing parts 134, 135 are Figure 9A The examples shown coincide, while Figure 9B In the embodiment shown, they are angled relative to each other.

[0194] Figure 10 A sectional view of a possible embodiment of a gas density meter 100, 200 is shown, which has a housing 102, 202, a connector 104, 204, a switching and / or monitoring unit 110, 210, an operating mechanism 130, 230, a display device 128, 228 with a pointer element 129, 229 and a pointer detection device 139, 239.

[0195] Pointer detection device 139 , 239 determines the position of pointer element 129 , 239 , which is schematically illustrated as magnetic element 169 , 269 , by means of a magnetic field sensor 156 , 256 (not shown in detail), for example a Hall element.

[0196] Pointer detection device 139, 239 is connected to signal contact device 140, 240, which can be in contact with external plug 152, 252. Plug 152, 252 is, for example, a component of an external monitoring and / or display unit (not shown in detail), by means of which information corresponding to the pointer position and thus describing the current gas density is output and / or corresponding measures are taken, for example, the information is transmitted to headquarters or maintenance and / or operating personnel.

[0197] Alternatively or additionally, pointer detection device 139 , 239 is connected to a radio device 141 , 241 , which emits a radio signal 142 , 242 , which includes the position of pointer element 129 , 229 .

[0198] The other structures and other functions of the gas density meter 100 , 200 correspond to one of the embodiments shown and described in the previous figures.

[0199] Figure 11 The wiring diagram of the coupling 104 , 204 of the gas density meter 100 , 200 is shown, which has a process connection 143 , a measuring connection 144 , a shut-off device 145 , an inlet connection 146 and a line system 147 .

[0200] The coupling 104 , 204 can be used to check the gas density meter 100 , 200 . To this end, the shut-off device 145 is first closed so that the gas density meter 100 , 200 is no longer connected to the gas chamber 1 .

[0201] A measuring device (not shown in detail) is then connected to the access port 146 , which applies a test pressure to the gas density meter 100 , 200 .

[0202] When the test is finished, the tester is isolated from the access port 146 again and the shutoff device 145 is opened. The gas density meter 100, 200 resumes its measurement function.

[0203] Figures 12A to 12D The sectional views show different embodiments of a gas densitometer 200 having two spring elements 215 , 231 and a second bellows 225 designed as a measuring bellows.

[0204] In all embodiments, the gas density meter 200 includes a housing 202, a first housing 203, a coupling 204, a first bellows 205, a second bellows 225 configured as a measuring bellows, a separating mechanism 208, a transmission element 209, a switching and / or monitoring unit 210, and a first spring element 215. The first spring element 215 is arranged in different positions in different embodiments. Furthermore, a second spring element 231 is provided, which is also arranged in different positions in different embodiments.

[0205] Figure 12A An exemplary embodiment is shown in which the first spring element 215 is arranged coaxially with the second fold 225 within the second fold. The second spring element 231 is arranged coaxially with the first fold 205 within the first fold.

[0206] Figure 12BAn exemplary embodiment is shown in which the first spring element 215 is arranged outside the second fold 225 so as to coaxially surround the second fold 225. The second spring element 231 is arranged outside the first fold 205 so as to coaxially surround the first fold 205.

[0207] Figure 12C An exemplary embodiment is shown in which the first spring element 215 is arranged coaxially with the second fold 225 within the second fold 225. The second spring element 231 is arranged coaxially around the first fold 205 outside the first fold 225.

[0208] Figure 12D An exemplary embodiment is shown in which the first spring element 215 is arranged outside the second fold 225 so as to coaxially surround the second fold 225. The second spring element 231 is arranged coaxially with the first fold 205 inside the first fold.

[0209] Figure 13A and 13B A cross-sectional view of the gas density meter 100 is shown when loaded with different pressures.

[0210] The gas density meter 100 includes a housing 102 , a first housing chamber 103 , a coupling 104 , a first bellows 105 , an isolation mechanism 108 , a transmission element 109 , a conversion and / or monitoring unit 110 , a second housing chamber 119 , an intermediate wall 120 and a connecting opening 121 .

[0211] In this case, the switching and / or monitoring unit 110 is arranged in the second housing 119 , wherein the transmission element 109 leads to the switching and / or monitoring unit 110 through a connecting opening 121 in the intermediate wall 120 .

[0212] Furthermore, a second bellows 125 is provided, which is connected with a first end section 180A to the separating means 108 and with a second end section 180B to the intermediate wall 120 and seals the second housing space 119 relative to the first housing space 103 .

[0213] The switching and / or monitoring unit 110 comprises a switching element 113 , a support element 148 and an operating element 149 having a key unit 150 .

[0214] exist Figure 13A In the embodiment, a lower first pressure exists inside the measuring chamber 168 and the key unit 150 and the switch element 113 are not in contact. If the pressure inside the measuring chamber 168 rises, the isolating mechanism 108 together with the transmission element 109 and the key unit 150 directly connected thereto moves downward, wherein, when a predetermined pressure value inside the measuring chamber 168 is exceeded, the key unit 150 is switched off according to the pressure. Figure 13BThe switch element 113 is operated by the key unit 150. The predetermined pressure value is defined by adjusting the relative position of the key unit 150 and the isolation mechanism 108, for example.

[0215] Figure 14 A cross-sectional view of a possible embodiment of a gas density meter 100 is shown having two monitoring sensors 162 and two monitoring displays 163 .

[0216] One of the monitoring sensors 162 is connected to the reference chamber 111 via a line 161 to detect the pressure of the reference gas 112 present within the reference chamber 111. To emit and / or transmit the detected value, the monitoring sensor 162 is coupled to the plug assembly 151. Furthermore, one of the monitoring displays 163 is connected to the reference chamber 111 to detect and display the pressure of the reference gas 112 present within the reference chamber 111.

[0217] Another monitoring sensor 162 is disposed within the second housing cavity 119 to detect the pressure within the second housing cavity. The monitoring sensor 162 is coupled to the plug assembly 151 to emit and / or transmit the detected value. Furthermore, the monitoring display 163 is coupled to the second housing cavity 119 to detect and display the pressure within the second housing cavity.

[0218] This embodiment enables the detection of various fault conditions. Furthermore, monitoring sensor 162 enables redundant pressure or density measurements compared to measurements using the original gas density meter 100, i.e., a mechanical bellows system, and electronic provision of the detected measured values. This significantly increases the operational reliability of gas density meter 100.

[0219] Figure 15 A sectional view of a portion of a gas densitometer 100, 200 is shown, which has a filling opening 171, 271 in the lower housing wall. The bellows 105, 205, that is, the reference chamber 111, 211, can be filled with a predetermined amount of reference gas 112, 212 via the filling opening 171, 271. After filling, the filling opening 171, 271 is closed by a closure element 172, 272.

[0220] Figure 16A and 16B Shown are views of possible embodiments of the isolation mechanism 108 from two sides and differently marked surfaces.

[0221] Figure 16A The first side of the separating means without the measuring bellows according to the second aspect of the invention is shown. The effective area, on which the gas in the measuring chamber 168 can exert pressure, is shown by hatching.

[0222] This is defined outwardly by the diameter of the bellows 105, that is to say the reference chamber 111, which is drawn with a dashed line. Outside the reference chamber 111, the pressures on the upper and lower sides of the separating means 108 caused by the gas in the measuring chamber 168 cancel each other out.

[0223] The inward direction is defined by the diameter of the second bellows 125 , that is to say the separating bellows, since the gas in the measuring chamber 168 cannot enter the separating bellows 125 and thus also cannot exert pressure on the surface section of the separating means 108 surrounded by the separating bellows 125 .

[0224] Figure 16B The other side of the isolation device 108 is shown. The area on which the reference gas 112 in the reference chamber 111 can exert pressure is shown by hatching. This area is limited only to the outside by the diameter of the fold 105, since the reference gas 111 is enclosed within the reference fold.

[0225] Through Figure 16A and 16B A comparison shows that reference gas 112 and the gas in measuring chamber 168 exert pressure on surfaces of different sizes on isolation member 108. The effective pressure surface of the gas in measuring chamber 168 is always smaller. Therefore, in reference chamber 111, the pressure of reference gas 112, which is lower than the pressure of the gas in measuring chamber 168, is sufficient to achieve a force balance between the opposing pressures.

[0226] Figures 17A to 17C The cross-sectional views show different designs of the pleat walls of the pleats 105 , 125 , 205 , 225 .

[0227] Here, the folded capsule wall can be constructed as a single-layer folded capsule wall ( Figure 17A ) or double-layer folded cyst wall ( Figure 17B ).

[0228] In a possible design solution, the intermediate space between the walls of the double-layer bellows wall is evacuated.

[0229] The invention is not limited to the detailed embodiments described above. The invention may be varied within the scope of the following claims. The individual aspects of the dependent claims may also be combined with one another.

[0230] Claim features introduced with “in particular”, “preferably” or “particularly preferably” are to be understood as optional features.

[0231] Reference Signs List

[0232] 1 Gas chamber

[0233] 100, 200 gas density meter

[0234] 102, 202 housing

[0235] 103, 203 First Shell Cavity

[0236] 104, 204 connectors

[0237] 105, 205 First fold capsule, reference fold capsule

[0238] 106A, 106B End section of the first fold

[0239] 107, 207 first inner wall section, inner wall section

[0240] 108, 208 Isolation Agency

[0241] 109, 209 transmission elements

[0242] 110, 210 conversion and / or monitoring unit

[0243] 111, 211 Reference Room

[0244] 112, 212 reference gas

[0245] 113, 213 switching elements

[0246] 114, 214 contact device

[0247] 115, 215 first spring element

[0248] 116 Longitudinal axis of the first fold

[0249] 117 End section of spring element

[0250] 118, 218 Second inner wall section

[0251] 119, 219 Second shell cavity

[0252] 120, 220 middle wall

[0253] 121, 221 connection opening

[0254] 122 Cross-sectional area of ​​the transfer element

[0255] 123 Cross-sectional area of ​​the first pleated capsule

[0256] 124 Sealing element

[0257] 125 Second fold capsule, isolation fold capsule

[0258] 225 Second fold capsule, measuring fold capsule

[0259] 126 Cross-sectional area of ​​the second fold

[0260] 127 first intermediate wall section

[0261] 128, 228 display devices

[0262] 129, 229 pointer components

[0263] 130, 230 operating organizations

[0264] 131, 231 Second spring element

[0265] 134, 234 First housing part

[0266] 135, 235 Second housing part

[0267] 139, 239 Pointer detection device

[0268] 140, 240 signal contact device

[0269] 141, 241 Radio Devices

[0270] 142, 242 radio signals

[0271] 143 Process Interface

[0272] 144 Measurement interface

[0273] 145 Cutting device

[0274] 146 Access Interface

[0275] 147 Piping System

[0276] 148, 248 Support elements

[0277] 149, 249 operating elements

[0278] 150, 250 key units

[0279] 151, 251 plug assembly

[0280] 152, 252 plugs

[0281] 153, 253 Spring element receiving portion

[0282] 154 Electric power switch

[0283] 155 housing connection

[0284] 156, 256 magnetic field sensors

[0285] 160 Entrance

[0286] Line 161

[0287] 162 Monitoring Sensors

[0288] 163 Monitor Display

[0289] 164 plated through holes

[0290] 165 Shell extension

[0291] 166 Monitoring contact device

[0292] 168, 268 Measurement Room

[0293] 169, 269 Magnetic components

[0294] 170, 270 Observation Window

[0295] 171, 271 filling port

[0296] 172, 272 closures

[0297] 180A, 180B: End sections of the isolation flap

[0298] 206A, 206B refer to the end sections of the folded capsule

[0299] 257A, 257B End section of the second fold

[0300] 258 Fourth inner wall section

[0301] 259 Fifth inner wall section

[0302] 267 suspension points

[0303] A Axis of symmetry of the first housing part

[0304] B Axis of symmetry of the second housing part

[0305] F1 cross-sectional area

[0306] B Cross-sectional area

[0307] pi Loading pressure

[0308] Ps Ultimate pressure

Claims

1. A gas density meter (100, 200) for monitoring the pressure or density of a gas in a gas chamber (1), the gas density meter comprising: A housing (102, 202) having a first housing cavity (103, 203) and a measuring chamber (168, 268), a first coupling (104, 204) via which the measuring chamber (168, 268) can be connected to the gas chamber (1), at least one reference fold (105, 205), which is in particular directly or indirectly connected to the transmission element (109, 209), and at least one switching and / or monitoring unit (110, 210) which is directly or indirectly in operative connection with or can be in operative connection with the transmission element (109, 209), Its characteristics are: The measuring chamber (168, 268) is gas-permeably connected to the gas chamber (1) via a first connector (104, 204), and The reference capsule (105, 205) forms a reference chamber (111, 211) which is filled with a constant amount of reference gas, and A surface section covering the reference chamber (111, 211) is provided or can be realized at least partially within the first housing (103, 203) or the measuring chamber (168, 268) as a measuring area for gas from the gas chamber.

2. The gas density meter (100, 200) according to claim 1, characterized in that: The surface section covering the reference fold (105, 205) has an effective measurement area that is 2% to 80% smaller, in particular 5% to 50% smaller, in particular 10% to 45% smaller, in particular 15% to 30% smaller than the cross-sectional area of ​​the reference fold (105, 205) or the cross-sectional area of ​​the surface section covering the reference fold (105, 205).

3. The gas density meter (100, 200) according to claim 1 or 2, characterized in that: The reference fold bladder (105, 205) has a diameter of 20mm to 70mm, or 30mm to 63mm, or 35mm to 55mm.

4. The gas density meter (100, 200) according to any one of the preceding claims, characterized in that: The reference fold (105, 205) has an effective measuring area or cross-sectional area perpendicular to the axis of the transmission element (109, 209), wherein the cross-sectional area has a width of 3 cm 2 Up to 40cm 2 or 7cm 2 Up to 30cm 2 or 10cm 2 Up to 25cm 2 area.

5. The gas density meter (100, 200) according to any one of the preceding claims, characterized in that: The pressure of the reference gas in the reference bellows (105, 205) is 0.05 bar to 2.5 bar, 0.5 bar to 1.0 bar, or 0.2 bar to 0.5 bar lower than the communication pressure of the gas chamber (1) in the normal operating state of the gas chamber (1).

6. The gas density meter (100, 200) according to any one of the preceding claims, characterized in that: The reference bellows (105, 205) is completely surrounded in an airtight manner by the housing (102, 202) or the shell cavity (103, 203).

7. The gas density meter (100, 200) according to any one of the preceding claims, characterized in that: The switching and / or monitoring unit (110, 210) comprises at least one switching element (113, 213), and when pressure equalization occurs between the measuring chamber (168, 268) and the reference chamber (111, 211), the at least one switching element (113, 213) is operated directly or indirectly by means of a transmission element (109, 209).

8. The gas density meter (100, 200) according to any one of the preceding claims, characterized in that: at least one first spring element (115, 215) which applies a spring force to the reference fold (105, 205) that counteracts the expansion of the reference fold (105, 205), and / or At least one second spring element (131, 231) applies a spring force to the reference fold (105, 205) that counteracts the compression of the reference fold (105, 205).

9. A gas density meter (100) for monitoring the pressure or density of gas in a gas chamber (1), the gas density meter comprising: A housing (102), the housing (102) comprising at least one first housing cavity (103), the first housing cavity (103) comprising a measuring chamber (168); at least one first connector (104), via which the gas density meter (100) can be connected to the gas chamber (1); at least one reference fold (105), which is directly or indirectly connected to a first inner wall section of the first housing (103) or the measuring chamber (168) at a first end section (106A); at least one isolating means (108), the isolating means (108) being directly or indirectly connected to the second end section (106B) of the reference folded bag (105) or being formed by the end section (106B); at least one transmission element (109) connected directly or indirectly to the isolation mechanism (108); At least one switching and / or monitoring unit (110) which is or can be in direct or indirect operative connection with the transmission element (109), wherein: The measuring chamber (168) is gas-permeably connected to the gas chamber (1) via a first connector (104), and The reference pleated capsule (105) forms a reference chamber (111) which is filled with a constant amount of reference gas (112), and The reference chamber (111) is at least partially arranged inside the first housing (103) and is hermetically isolated from the measuring chamber (168).

10. A gas density meter (200) for monitoring the pressure or density of gas in a gas chamber (1), the gas density meter comprising: A housing (202), the housing (202) comprising at least one first housing cavity (203); at least one first connector (204), via which the gas density meter (200) can be connected to the gas chamber (1); A reference folded capsule (205) is directly or indirectly connected to a first inner wall section (207) of the first housing cavity (203) at a first end section (206A); a measuring folded bag (225) which is directly or indirectly connected to the second inner wall section (218) of the first shell cavity (203) at the first end section (257A); at least one isolation mechanism (208), the isolation mechanism (208) being directly or indirectly connected to the second end section (206B) of the reference folded capsule (205) and the second end section (257B) of the measuring folded capsule (225), or being formed by the second end section (206B) of the reference folded capsule (205) or by the second end section (257B) of the measuring folded capsule (225); a transmission element (209) connected directly or indirectly to the isolation mechanism (208); and At least one switching and / or monitoring unit (210) which is or can be in direct or indirect operative connection with the transmission element (209), wherein The reference pleated capsule (205) forms a reference chamber (211) which is filled with a constant amount of reference gas (212), and The measuring bellows (225) forms a measuring chamber (268) which is gas-permeably connected to the gas chamber (1) via a connector (204), and The measuring chamber (268) and the reference chamber (211) are hermetically isolated from each other.

11. The gas density meter (100, 200) according to claim 9 or 10, wherein: The switching and / or monitoring unit (110, 210) comprises at least one switching element (113, 213), and the at least one switching element (113, 213) can be operated directly or indirectly by means of a transmission element (109, 209), and the switching and / or monitoring unit (110, 210) Either each switching element (113, 213) comprises at least one electrical contact device (114, 214) assigned to the switching element (113, 213), wherein the at least one electrical contact device (114, 214) is electrically connected to the switching element (113, 213) and is accessible from outside the housing (102, 202), Either it comprises at least one radio device (141, 241) connected to at least one switching element (113, 213), which detects the switching state of the switching element (113, 213) and emits it as a radio signal (142, 242).

12. The gas density meter (100, 200) according to any one of claims 9 to 11, in, At least one first spring element (115, 215) is provided for applying a force directly or indirectly to the isolation mechanism (108, 208), In particular, it is provided that the first spring element (115, 215) is disposed inside the first housing (103, 203), and / or provided inside the reference chamber (111, 211) or inside the measurement chamber (168, 268), and / or is arranged at least substantially parallel to the longitudinal axis (116) of the reference fold (105, 205), Among them, it stipulates in particular: The first end section (117) of the first spring element (115, 215) is in direct or indirect mechanical contact with the isolating mechanism (108, 208), and / or The second end section (117) of the first spring element (115, 215) is in direct or indirect mechanical contact with the third inner wall section of the first housing (103, 203).

13. The gas density meter (100, 200) according to any one of claims 9 to 12, in, The housing (102, 202) includes at least one second housing cavity (119, 219), A connecting opening (121, 221) is provided in an intermediate wall (120, 220) between the at least two housing cavities (103, 119, 203, 219), and The transmission element (109, 209) extends from the first housing cavity (103, 203) through the connecting opening (121, 221) into the second housing cavity (119, 219). The housings (103, 119, 203, 219) are particularly sealed relative to one another, and The transfer element (109, 209) has a cross-sectional area (122) that is smaller than a cross-sectional area (123) of the reference fold (105, 205).

14. The gas density meter (100, 200) according to claim 13, wherein: In order to seal the first and second housings (119, 219) relative to each other, A sealing element (124) is provided, which is sealingly arranged between the connecting opening (121, 221) and the transfer element (109, 209) protruding through the connecting opening (121, 221), or A separating fold (125) is provided, which is directly or indirectly connected to the separating means (108, 208) and the intermediate wall section, so that the separating fold (125) at least partially surrounds the transfer element (109, 209). wherein the connecting opening (121, 221) is located in this intermediate wall section, and The isolation pleat (125) has a diameter smaller than that of the reference pleat (105, 205).

15. The gas density meter (100, 200) according to any one of claims 9 to 14, wherein: The constant amount of reference gas (112, 212) in the reference chamber (111, 211) is determined as follows: when the measuring chamber (168, 268) is loaded with a first pressure existing in the normal operating state of the gas chamber (1), a second pressure is generated in the reference chamber (111, 211) in the balance of all acting pressures, mechanical stresses and / or spring forces, which second pressure is lower than the first pressure, in particular at least 0.1 bar or 0.2 bar lower than the first pressure.

16. The gas density meter (100, 200) according to any one of claims 9 to 15, in, The switching and / or monitoring unit (110, 210) comprises a display device (128, 228) with a pointer element (129, 229) and an operating mechanism (130, 230), The transmission element (109, 209) is directly or indirectly operatively connected to the operating mechanism (130, 230), and the movement of the transmission element (109, 209) directly or indirectly causes the movement of the pointer element (129, 229) via the operating mechanism (130, 230).

17. The gas density meter (100, 200) according to any one of claims 11 to 16, wherein: The at least one switching element (113, 213) and the transmission element (109, 209) are arranged and are directly or indirectly connected to each other or can be connected to each other in such a manner that the switching element (113, 213) - is operated directly or indirectly by means of the transmission element (109, 209) when the gas density meter (100, 200) is loaded with a pressure equal to or greater than the limit pressure, and - interrupting the direct or indirect actuation by means of the transmission element (109, 209) when the impinging pressure drops below the limit pressure.

18. The gas density meter (100, 200) according to any one of claims 12 to 17, in, A second spring element (131, 231) is provided, wherein the first spring element (115, 215) and the second spring element (131, 231) directly or indirectly exert a spring force on the isolation mechanism (108, 208), and In particular, it is provided that the second spring element (131, 231) is disposed inside the first housing (103, 203), and / or provided inside the reference chamber (111, 211) or inside the measurement chamber (168, 268), and / or is arranged substantially parallel to the longitudinal axis (116) of the reference pleat (105, 205), Among them, it stipulates in particular: The first end section of the second spring element (131, 231) is in direct or indirect mechanical contact with the isolation mechanism (108, 208), and / or The second end section of the second spring element (131, 231) is in direct or indirect mechanical contact with the fourth inner wall section of the first housing cavity (103, 203).

19. The gas density meter (100, 200) according to any one of claims 13 to 18, wherein: The housing (102, 202) is a multi-piece housing (102, 202), At least the first housing cavity (103, 203) is provided in the first housing portion, and At least one further housing chamber (119, 219) is arranged in the second housing part, wherein The first and second housing parts are connected to each other directly or indirectly, and / or The housing parts are rotatable relative to one another about at least one rotational axis.

20. The gas density meter (100, 200) according to claim 19, wherein The first housing part and the second housing part have at least substantially a cylindrical form, wherein The axis of symmetry (A) of the first housing part extends at least substantially parallel to the axis of symmetry (B) of the second housing part and / or extends at least substantially coincidingly, or The axis of symmetry (A) of the first housing part extends at least substantially in a plane perpendicular to the axis of symmetry (B) of the second housing part, and / or the axis of symmetry (A) of the first housing part and the axis of symmetry (B) of the second housing part intersect at least substantially perpendicularly to each other.

21. The gas density meter (100, 200) according to any one of claims 17 to 20, wherein: The constant amount of reference gas (112, 212) in the reference chamber (111, 211) is determined as follows: when the measuring chamber (168, 268) is loaded with a first pressure existing in the normal operating state of the gas chamber (1), a second pressure is generated in the reference chamber (111, 211) in the balance of all acting pressures, mechanical stresses and / or spring forces, which second pressure is lower than the limit pressure, in particular at least 0.1 bar or 0.2 bar lower than the limit pressure, wherein the limit pressure is lower than the first pressure.

22. The gas density meter (100, 200) according to any one of claims 16 to 21, wherein: The conversion and / or monitoring unit (110, 210) comprises: a pointer detection device (139, 239) configured to detect the position of a pointer element (129, 229) and convert it into an electrical signal, and a signal contact device (140, 240) electrically connected to the pointer detection device (139, 239) and accessible from outside the housing (102, 202), or A radio device (141, 241) is electrically connected to a pointer detection device (139, 239) and transmits an electrical signal of the pointer detection device (139, 239) as a radio signal (142, 242).

23. The gas density meter (100, 200) according to any one of claims 9 to 22, wherein: The coupling (104, 204) comprises: A process interface (143) for connecting to the gas chamber (1); A measurement interface (144) connected to the gas density meter (100, 200); Cutting device (145); access interface (146); and a pipeline system (147) which connects the access interface (146), the process interface (143), the measuring interface (144) and the shut-off device (145) to one another in a gas-permeable manner, The shut-off device (145) is arranged in the pipeline system (147), so that the connection between the process interface (143) and the measuring interface (144) and the connection between the process interface (143) and the access interface (146) can be shut off by the shut-off device (145), wherein the measuring interface (144) and the access interface (146) are continuously connected to each other in an airtight manner.

24. The gas density meter (100, 200) according to any one of claims 13 to 23, wherein: A reference chamber (111, 211), a measuring chamber (168, 268), an isolation mechanism (108, 208) and a transfer element (109, 209) are provided in the first housing (103, 203), and A switching and / or monitoring unit (110, 210) is arranged in the second housing (119, 219).

25. The gas density meter (100, 200) according to any one of claims 18 to 24, wherein: A first spring element (115, 215) and / or a second spring element (131, 231) are arranged in the first housing (103, 203), and The at least one switching element (113, 213) is arranged in the second housing (119, 219).

26. The gas density meter (100, 200) according to any one of claims 9 to 25, wherein: The reference chamber (111, 211) is partially defined by a first surface section of the isolation means (108, 208), and The measuring chamber (168, 268) is partially defined by a second surface section of the isolation means (108, 208), and The first surface section is larger than the second surface section, in particular at least 2% or at least 25% larger than the second surface section.

27. The gas density meter (100, 200) according to any one of claims 12 to 26, wherein: The first spring element (115, 215) is a coil spring and has at least: Spring strength of at least 15N / mm; Spring diameters from 5mm to 35mm; and / or Wire diameter of 1.5 mm to 6 mm, in particular 2 mm to 5 mm.

28. The gas density meter (100, 200) according to any one of claims 18 to 27, wherein: The second spring element (131, 231) is a coil spring and has at least: Minimum spring strength of 15N / mm; 5mm to 35mm spring diameter, and / or Wire diameter of 1.5 mm to 6 mm, in particular 2 mm to 5 mm.

29. The gas density meter (100, 200) according to any one of claims 9 to 28, wherein: The reference capsule (105, 205) has: Spring strengths between 15 N / mm and 65 N / mm, and / or An inner diameter of at least 5 mm, and / or 30mm to 63mm outer diameter, and / or 0.1mm to 0.4mm wall thickness, and / or An outer edge with a radius of curvature of 2 to 4 mm, and / or An inner edge with a radius of curvature of 0.5 mm to 1.5 mm, and / or The reference bellows (105, 205) is particularly designed as a double-layer bellows, and the middle space of the double-layer bellows is particularly evacuated.

30. The gas density meter (100, 200) according to any one of claims 10 to 29, wherein: The measuring bag (225) has: Spring strengths between 15 N / mm and 65 N / mm, and / or An inner diameter of at least 5 mm, and / or 30mm to 63mm outer diameter, and / or 0.1mm to 0.4mm wall thickness, and / or An outer edge with a radius of curvature of 2 to 4 mm, and / or An inner edge with a radius of curvature of 0.5 mm to 1.5 mm, and / or The measuring folded bag (225) is particularly designed as a double-layer folded bag, and the middle gap of the double-layer folded bag is particularly vacuumed.

31. The gas density meter (100, 200) according to any one of claims 14 to 30, wherein: The isolation folded bag (125) has: Spring strength from 1.5 N / mm to 25 N / mm, and / or An inner diameter of at least 4 mm, and / or 8mm to 18mm outer diameter, and / or 0.1mm to 0.4mm wall thickness, and / or The isolation folded bag (125) is particularly designed as a double-layer folded bag, and the middle gap of the double-layer folded bag is particularly vacuumed.

32. The gas density meter (100, 200) according to any one of claims 9 to 31, wherein: The housing (102, 202) includes: filling port (171, 271), and Closure (172, 272), A gas-permeable passage to the reference chamber (111, 211) is created via the filling opening, and the filling opening is tightly closed by a closure element (172, 272), wherein the closure element (172, 272) comprises: Bolts with gaskets, or Pressed rivets, or A sphere, in particular a sphere with a spring, or A positioning pin, in particular a positioning pin which is welded sealingly into the filling opening.

33. The gas density meter (100, 200) according to any one of claims 9 to 32, in, At least one inlet (160) is provided on the reference chamber (111, 211) and / or the measuring chamber (168, 268), wherein at least one monitoring display (163) or at least one monitoring sensor (162) is connected to the inlet (160) and / or is air-permeably connected to the connecting opening (121, 221) via a line (161), The monitoring display (163) or the monitoring sensor (162) monitors or displays the pressure in the measuring chamber (168, 268).

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