Fire alarm device

Abstract

Fire alarm device (1) with at least one fire sensor unit (4) for fire detection, with at least one alarm unit (5, 6) which is designed to emit an alarm signal upon fire detection, wherein the at least one fire sensor unit (4) is a fire sensor module (4) and the at least one alarm unit (5, 6) is an alarm module (5, 6), wherein the fire sensor module (4) and the alarm module (5, 6) are designed as separate modules, wherein the at least one fire sensor module (4) and the at least one alarm module (5, 6) each have a coupling housing (7), wherein the coupling housings (7) each comprise a mechanical coupling device (9) via which the coupling housings (7) can be connected or are connected in a modular manner, and wherein the mechanical coupling devices (9) of the coupling housings (7) to be coupled are designed as a mechanical interface (9a) and a mechanical counter-interface (9b), characterized by that the mechanical interface (9a) is designed as a locking lug (9a) and the mechanical counter-interface (9b) as a locking receptacle (9b), wherein the locking lug (9a) in the locking receptacle (9b) can be switched between a coupling position and a release position, and that an acoustic alarm module (6) of the at least one alarm module (5, 6) has a plurality of acoustic openings (14) which are arranged at a distance from one another on a peripheral wall of the coupling housing (7).

Description

State of the art

[0001] The invention relates to a fire alarm device according to the features of the preamble of claim 1.

[0002] Fire detectors are used to detect fires and trigger an alarm when a fire is detected. Fire detectors are used in private facilities, public areas, or industrial environments, for example, to detect a fire in an area early and trigger an alarm.

[0003] For example, DE 198 08 872 A1 discloses a ceiling-mounted detector with externally visible illuminated indicators for the alarm status. The detector has one or more illuminated surfaces arranged in a ring on the part of the detector surface that is visible during operation and radiates light in different directions.

[0004] A modular building system arrangement with a large number of modules is known from US 2014 / 0 002 648 A1.

[0005] DE 20 2010 006 632 U1 discloses a smoke detector with a housing having a longitudinal axis, wherein the housing has a continuous recess parallel to the axis.

[0006] US 2012 / 0 032 815 A1 discloses a method and system for determining at least one property of a strobe cover. The determined property of the strobe cover is analyzed to determine whether it is the correct property for the strobe device.

[0007] US 2006 / 0 033 344 A1 discloses a vehicle lock and a method for its manufacture.

[0008] From DE 10 2005 021 165 A1 a trim part, in particular for a vehicle, is known, wherein the trim part comprises a hard section made of hard plastic and a connecting element made of plastic, which are permanently connected to one another to form a component. Disclosure of the invention

[0009] Within the scope of the invention, a fire alarm device with the features of claim 1 is proposed. Preferred or advantageous embodiments emerge from the subclaims, the following description and the attached figures.

[0010] According to the invention, a fire alarm device for fire detection is thus proposed. For example, the fire alarm device is intended for installation in private facilities, public areas, or industrial environments. The fire alarm device is designed, for example, as a fire gas, smoke gas, heat, smoke, flame, or multi-criteria detector. The fire alarm device can be installed as a surface-mounted or flush-mounted detector on a ceiling or wall of a room.

[0011] The fire alarm device comprises at least or exactly one fire sensor unit for fire detection. In particular, the fire sensor unit comprises at least one sensor designed to record fire-specific measured values. Particularly preferably, the fire sensor unit comprises an optical sensor. In particular, the optical sensor has a light emitter and a light receiver, which are arranged at an angle to one another in a measuring chamber. If smoke particles are present in the measuring chamber, the light emitted by the light emitter is scattered to the light receiver, whereby the light intensity scattered to the light receiver forms the fire-specific measured value. As an exemplary alternative or optional addition, the fire sensor unit can comprise a thermal sensor, a humidity sensor, and / or a gas sensor.

[0012] The fire alarm device preferably comprises or is connectable to an evaluation device. The evaluation device is preferably designed to detect the fire based on the fire-specific measurement parameters transmitted by the fire sensor unit.

[0013] The fire alarm device comprises at least one alarm unit configured to output an alarm signal upon fire detection. In particular, the alarm unit outputs the alarm signal in a room located within the fire alarm device to signal a fire alarm to persons in the vicinity. For example, the evaluation device is coupled to the at least one alarm unit to trigger the output of the alarm signal upon fire detection. Optionally, the fire alarm device can additionally comprise a data interface, wherein the fire alarm device is configured to output a fire detection alarm via the data interface to a data network and, for example, to a fire alarm control center or to rescue personnel.

[0014] Within the scope of the invention, it is proposed that the at least one fire sensor unit be a fire sensor module and the at least one alarm unit be an alarm module, wherein the fire sensor module and the alarm module are designed as separate modules. In particular, the separate modules are independent individual structures with defined interfaces. The defined interfaces enable the at least one fire sensor module and the at least one alarm module to be connected to one another in a compatible manner. In particular, the separate modules are designed to be pluggable and / or lockable without the need for tools.

[0015] The separate modular design enables, in particular, standardized production of the fire sensor and alarm modules. This lowers development and manufacturing costs for the fire detection device. Furthermore, the separate modular design allows for easy module replacement, installation, maintenance, and repair of the fire detection device.

[0016] Furthermore, the modularity of the fire sensor and alarm modules enables a greater product variety of fire detection devices. This makes it possible to offer fire sensor modules and alarm modules with different functions, numbers, and / or arrangements for the fire detection device. This allows for a customized fire detection device that reliably detects fires for specific application conditions. Furthermore, the separate modular design ensures that there is no mutual interference between the sensors when multiple fire sensor modules are used.

[0017] A preferred embodiment provides that the fire alarm device comprises a further alarm module, wherein one of the at least two alarm modules is designed as an optical alarm module. In particular, the optical alarm module emits an optical alarm signal upon fire detection. For example, the optical alarm module comprises at least one, but preferably a plurality of, light sources that emit the optical alarm signal in the room located near the fire alarm device. The at least one light source is designed, for example, as a light-emitting diode, incandescent lamp and / or as a luminous foil. Preferably, the other of the at least two alarm modules is designed as an acoustic alarm module. In particular, the acoustic alarm module emits an acoustic alarm signal upon fire detection. For example, the acoustic alarm module comprises at least one siren that emits the acoustic alarm in the room located near the fire alarm device.The combination of the optical and acoustic alarm signal is intended to increase the probability that all persons in the vicinity of the fire alarm device receive information about the fire alarm as soon as possible.

[0018] According to the invention, the structural design provides that the at least one fire sensor module and the at least one alarm module each have a coupling housing, wherein the coupling housings each comprise a mechanical coupling device via which the coupling housings can be modularly connected or are connected. Particularly preferably, the mechanical coupling device is designed as a positive-locking coupling device, alternatively or optionally additionally as a force-fitting or material-fitting coupling device.

[0019] According to the invention, the mechanical coupling devices of the coupling housings to be coupled are designed as a mechanical interface and a mechanical counter-interface. For example, the coupling housing of the at least one alarm module has the mechanical interface, and the coupling housing of the at least one fire sensor module to be coupled has the mechanical counter-interface, or vice versa. Particularly preferably, the mechanical interfaces and the mechanical counter-interfaces in the fire alarm device are each constructed identically. This allows for versatile variation of the modules, as well as their replacement or addition.

[0020] In particular, the mechanical coupling devices of the coupling housings to be coupled are designed as a quick-release device. The quick-release device is preferably designed such that the mechanical interface and the mechanical counter-interface can be detachably coupled and / or locked, in particular without the use of tools. For example, the mechanical interface of the quick-release device is designed as a plug-in element and the mechanical counter-interface as a plug-in receptacle, which can be plugged into one another in a self-retaining manner and separated from one another non-destructively.

[0021] According to the invention, the mechanical interface is designed as a locking lug and the mechanical counter-interface as a locking receptacle, wherein the locking lug in the locking receptacle can be switched between a release and a coupling position. Preferably, the locking lug can be moved in and out of the locking receptacle in the release position in the direction of a main axis. The main axis is in particular an axial central axis of the fire alarm device. In particular, the separate components are connected to one another in the coupling position without the need for removal, wherein the components can be separated from one another in the release position. In particular, the locking receptacle comprises a snap-in edge. Preferably, the locking lug is designed to overcome the snap-in edge of the locking receptacle by elastic deformation during displacement from the release to the coupling position and then to engage behind the snap-in edge and to hold itself in the locking receptacle.A particular advantage of this implementation is that the modules can be inserted or replaced by the operator without the need for tools, or at least with minimal effort. This makes the coupling devices easy to install.

[0022] It is preferred that the coupling housing with the locking lug has an adjusting device that can be switched between a first and a second position. In particular, the adjusting device is designed to switch the locking lug into the release position in the first position and into the coupling position in the second position. The adjusting device is preferably designed as a switch or lever. It is preferred that the adjusting device is integrally connected to the locking lug. For example, the adjusting device is arranged on a peripheral wall of the coupling housing, so that the operator can switch between the coupling and release positions quickly and easily.

[0023] In one possible embodiment of the invention, the coupling housings with the mechanical interface, in particular with the locking lug, are each designed as a two-component injection-molded part, wherein a base housing is made from a first component and the mechanical interface, in particular the locking lug, optionally with the switch or the lever, is made from a second component. In particular, the base housing and the mechanical interface are two separate, and therefore not integrally connected, components. Preferably, the mechanical interface is arranged captively in the base housing. In particular, the two-component injection-molded part is manufactured using multi-component injection molding. In the multi-component injection molding process, at least two injection molding units are used, which operate in one tool.Multi-component injection molding allows individual components—here the coupling housing and the mechanical interface—to be manufactured with a single tool. This eliminates the need for complex assembly of the locking lug into the coupling housing.

[0024] A preferred development provides that the base housing and the mechanical interface, in particular the locking lug for switching between the coupling and release positions, have different plastic shrinkage dimensions. In particular, the base housing has a smaller plastic shrinkage dimension than the mechanical interface, so that the mechanical interface is designed to be movable in the coupling housing after the shrinkage process. To achieve the different plastic shrinkage dimensions, the base housing and the mechanical interface are made, for example, from different plastics or from a plastic with different additives. The different plastic shrinkage dimensions enable the locking lug and the base housing to be movable relative to one another in multi-component injection molding, in particular in assembly injection molding.This allows the multi-component injection molding process to be used for the base housing and the locking lug. Multi-component injection molding enables a reduction in manufacturing costs for the base housing and the locking lug, particularly in large-scale production. Furthermore, the integration of the locking lug into the base housing minimizes assembly effort for the installer.

[0025] In one possible implementation of the invention, it is provided that the coupling housings of the at least one fire sensor module and / or the at least one alarm module each comprise an electrical coupling device via which the coupling housings can be or are electrically connected. In this way, an electrical supply and / or a data connection of the separate modules is ensured. Particularly preferably, the electrical coupling devices of the coupling housings to be coupled are designed as an electrical interface and as an electrical counter-interface. For example, the coupling housing of the at least one alarm module has the electrical interface and the coupling housing of the at least one fire sensor module has the electrical counter-interface, or vice versa.The plug-in direction of the electrical interfaces and counter-interfaces runs in particular in the direction of the main axis of the fire alarm device and / or in the direction of the mechanical interfaces and counter-interfaces to be connected. Preferably, the electrical interfaces and the electrical counter-interfaces in the fire alarm device are each constructed identically. This reliably enables versatile variation of the modules, as well as the replacement or addition of the modules. For example, the electrical interface is designed as a plug, and the electrical counter-interface as a socket with a complementary coupling structure.

[0026] In particular, it is provided that the coupling housings each have a mechanical guide device designed to specify a specific mounting direction and / or mounting position of the coupling housings relative to one another for the modular connection. Thus, the guide device forms an assembly aid that ensures a correct connection of the mechanical and / or electrical cutting and counter-interfaces of the construction modules by specifying exactly one mounting option for the construction modules. For example, the mechanical guide devices of the coupling housings to be coupled are designed as a mechanical guide point, in particular as a guide web, and a mechanical counter-guide point, in particular as a guide bushing. Particularly preferably, the mechanical guide points and the mechanical counter-guide points in the fire alarm device are each of identical construction.Preferably, the guide web in the counter-guide point can be moved in and out in exactly one direction of movement, in particular in the direction of the main axis.

[0027] It is preferred that the optical alarm module comprises a plurality of light sources, which are arranged, in particular, on a peripheral wall of the coupling housing at a distance from one another in the circumferential direction. The arrangement of the light sources on the reverse side leads to reliable detection of the optical alarm signal.

[0028] According to the invention, the acoustic alarm module has a plurality of acoustic openings which are arranged spaced apart from one another in the circumferential direction, in particular on the peripheral wall of the coupling housing.

[0029] The arrangement of the acoustic openings on the reverse side ensures that the acoustic fire signal is spread evenly throughout the room.

[0030] From a structural perspective, it is particularly preferred that the peripheral walls of the coupling housings of the at least one fire sensor module and / or the at least one alarm module, in particular of the two alarm modules, are flush with one another. This visually enhances the appearance of the fire detection device. Furthermore, standardized production and modular connection of the modules are simplified.

[0031] A particularly preferred, specific embodiment of the invention provides that the coupling housing of the acoustic alarm module forms a wall coupling housing, the coupling housing of the optical alarm module forms an intermediate coupling housing, and the coupling housing of the fire sensor module forms an end coupling housing. In particular, the wall coupling housing is the coupling element to the wall or ceiling of the room in which the fire alarm device is to be arranged. In particular, the end coupling housing is arranged at the free end of the fire alarm device opposite the wall coupling housing and is to be oriented toward the room. Preferably, the wall coupling housing, the intermediate coupling housing, and the end coupling housing together form a cylindrical shape when coupled.

[0032] Further features, advantages, and effects of the invention will become apparent from the following description of preferred embodiments of the invention. These show: Fig. 1 shows an exploded view of a fire alarm device as an embodiment of the invention; Fig. 2 an optical and an acoustic alarm module of the fire detection device Fig. 1; Fig. 3a, Fig. 3b a mechanical coupling unit in a release and a coupling position for the modular connection of separate modules of the fire alarm device from Fig. 1.

[0033] Fig. Figure 1 shows a fire alarm device 1. The fire alarm device 1 can be configured, for example, as a fire gas detector, smoke detector, heat detector, smoke detector, flame detector, or as a multi-criteria detector. In this embodiment, the fire alarm device 1 is configured as a scattered light detector with a labyrinth 2.

[0034] The fire alarm device 1 is designed as a surface-mounted fire alarm device. Here, the fire alarm device 1 is supplied with power via a power cable connection and / or data transmission cable connection 3. As an alternative to the power cable connection 3, the fire alarm device 1 can also be operated in an energy-autonomous manner, e.g., via an integrated energy storage device such as a battery or accumulator.

[0035] The fire alarm device 1 comprises a fire sensor unit 4 for fire detection. Due to the design of the fire alarm device 1 as a scattered light detector, the fire sensor unit 4 comprises an optical sensor system. The optical sensor system is designed in particular to measure the light intensity scattered by smoke particles as a fire-specific measured value. For example, the fire alarm device 1 comprises or can be connected to an evaluation device. The evaluation device is designed to detect the fire based on the fire-specific measured values ​​recorded by the fire sensor unit 4.

[0036] The fire alarm device 1 comprises two alarm units 5, 6, which are designed to output an alarm signal upon fire detection. For example, the two alarm units 5, 6 are controlled by the evaluation unit to output an alarm if the evaluation unit has detected a fire. Optionally, the fire alarm device 1 can additionally have a data interface, wherein the fire alarm device 1 is designed to output an alarm signal for fire detection via the data interface to a data network and, for example, to a fire alarm control center or to rescue personnel.

[0037] The first of the two alarm units 5, 6 is an optical alarm unit 5 and the second of the two alarm units is an acoustic alarm unit 6. The alarm units 5, 6 are designed to emit an optical or acoustic alarm signal when a fire is detected.

[0038] The first and second alarm units 5, 6 are designed as alarm modules 5, 6, and the fire sensor unit 4 is designed as a fire sensor module 4, wherein the alarm modules 5, 6 and the fire sensor module 4 are separate modules. The separate modular design of the alarm modules 5, 6 and the fire sensor module 4 advantageously implements a standardization of the interface connection of the modules 4, 5, 6. This simplifies the installation, maintenance, and repair of the fire detection device 1.

[0039] The separate construction modules 4, 5, 6 each have a coupling housing 7, via which the construction modules 4, 5, 6 can be modularly connected. The coupling housings 7 are to be arranged in exactly one direction of movement relative to a main axis A of the fire alarm device 1 in order to be modularly connected to one another. The main axis A is an axial center axis of the fire alarm device 1. In the coupled state, the coupling housings 7 are connected in series to the main axis A. Furthermore, the coupling housings 7 are arranged coaxially to the main axis A. In addition, the peripheral walls of the coupling housings 7 form a flush connection with one another.

[0040] The optical alarm unit 5 comprises a plurality of light sources 13 arranged on the peripheral wall of the coupling housing 7 at a distance from one another in the circumferential direction. The acoustic alarm unit 6 comprises a plurality of acoustic openings 14 arranged on the peripheral wall of the coupling housing 7 at a distance from one another in the circumferential direction.

[0041] For the power supply and data transmission of the construction modules 4, 5, 6, the coupling housings 7 each have an electrical coupling device 8, via which the coupling housings 7 can be electrically connected. The electrical coupling devices 8 of the coupling housings 7 to be coupled are designed as an electrical interface 8a and as an electrical counter-interface 8b. The electrical counter-interface 8b is concealed by the coupling housing 7 and is therefore not shown. The electrical interfaces 8a are designed as a plug and the electrical counter-interfaces 8b as a socket. The electrical interfaces 8a and counter-interfaces 8b are arranged parallel to the main axis A. This ensures that the electrical interface and counter-interfaces 8a, 8b are automatically coupled to one another when the coupling housings 7 are arranged.In this way, additional work steps for the electrical connection of modules 4, 5, 6 are eliminated.

[0042] As in Fig. 2, the coupling housings 7 each comprise a mechanical coupling device 9, via which the coupling housings 7 can be modularly connected. The mechanical coupling device 9 is designed such that the modular connection of the separate modules 4, 5, 6 can be implemented without tools. Thus, the mechanical coupling device 9 implements an assembly-friendly, modular connection. The mechanical coupling devices 9 of the coupling housings 7 to be coupled are a mechanical interface 9a and a mechanical counter-interface 9b. The mechanical counter-interface 9b is concealed by the coupling housing 7 and is therefore in the Fig. 2 not shown. The mechanical interface 9a is designed as a locking lug 9a, and the mechanical counter-interface 9b is designed as a locking receptacle 9b. For the modular connection of the building modules 4, 5, the locking lugs 9a and the locking receptacles 9b are arranged parallel to the main axis A. Thus, the locking lugs 9a are automatically inserted into the locking receptacles 9b when the building modules 4, 5, 6 are arranged relative to one another.

[0043] Based on the Fig. 3a, Fig. Figure 3b explains the modular connection of the modules 4, 5, and 6 in more detail. To provide a captive connection of the modules 4, 5, and 6, the locking lug 9a in the locking receptacle 9b can be switched between a release and a coupling position. Fig. Figure 3a shows the locking lug 9a in the locking receptacle 9b in the release position. In the release position, the locking lug 9a can be moved in and out of the locking receptacle 9b in the direction of the main axis A. Thus, the coupling housings 7 are arranged detachably relative to one another. Fig. Figure 3b shows the locking lug 9b in the locking receptacle 9b in the coupling position. In the coupling position, the locking lug 9a is arranged in the locking receptacle in a manner that prevents removal, so that the coupling housings 7 are firmly connected to each other.

[0044] To transfer the locking lug 9a between the coupling and release positions, it is designed to be movable in a direction of movement B between the release and coupling positions. The direction of movement runs, for example, in the direction of rotation relative to the main axis A. The locking receptacle 9b has an undercut 10 formed by a snap-in edge. The locking lug 9a overcomes the snap-in edge during the transfer from the release to the coupling position, in order to then hold itself in the coupling position in the locking receptacle 9a, specifically by means of the undercut 10, in a secured manner in the locking receptacle 9b.

[0045] The coupling housing 7 with the locking lug 9a includes an adjusting device 11, which is accessible to the operator for switching the locking lug 9a between the release and coupling positions on the peripheral wall. The adjusting device 11 is integrally connected to the locking lug 9a. Thus, when the adjusting device 11 is moved, the locking lug 9a is also moved.

[0046] The coupling housings 7 with the locking lug 9a each comprise a base housing and the locking lug 9a, wherein the coupling housings 7 are each formed as a two-component injection-molded part. The base housing and the locking lug 9a each have different plastic shrinkage rates. For example, the plastic from which the locking lug 9a is formed has a higher shrinkage behavior than the plastic from which the base housing is formed. Thus, the locking lug 9a, which is still immovably arranged in the base housing after the multi-component injection molding, becomes movable in the base housing after the shrinkage process. Thus, the coupling housing 7 can be manufactured economically in large-scale production using multi-component injection molding.

[0047] As from the Fig.1, the coupling housings 7 each comprise a mechanical guide device 12. The mechanical guide device 12 is designed as a mechanical guide point 12a and as a mechanical counter-guide point 12b. The mechanical guide point 12 is a guide web and the mechanical counter-guide point 12b is a guide bushing. The mechanical guide device 12 defines a specific relative position of the coupling housings 7 to one another so that the modular connection of separate components 4, 5, 6 is possible. The mechanical guide device 12 ensures that the coupling housings 7 are arranged in the correct relative position to one another for the modular connection and thus that the mechanical and electrical interfaces and counter interfaces 8a, 8b, 9a, 9b are connected to one another.

[0048] The fire sensor module 4 is arranged at one of the two free ends of the fire alarm device 1 in the direction of the main axis A. This provides direct access to the room and thus, in particular, unrestricted fire detection. The acoustic alarm module 6 is arranged at the second of the two free ends of the fire alarm device 1 and forms the coupling element to the wall or ceiling of the room in which the fire alarm device 1 is to be arranged.

Claims

[1] Fire alarm device (1) with at least one fire sensor unit (4) for fire detection, with at least one alarm unit (5, 6) which is designed to emit an alarm signal upon fire detection, wherein the at least one fire sensor unit (4) is a fire sensor module (4) and the at least one alarm unit (5, 6) is an alarm module (5, 6), wherein the fire sensor module (4) and the alarm module (5, 6) are designed as separate modules, wherein the at least one fire sensor module (4) and the at least one alarm module (5, 6) each have a coupling housing (7), wherein the coupling housings (7) each comprise a mechanical coupling device (9) via which the coupling housings (7) can be connected or are connected in a modular manner, and wherein the mechanical coupling devices (9) of the coupling housings (7) to be coupled are designed as a mechanical interface (9a) and a mechanical counter-interface (9b), characterized by , that the mechanical interface (9a) is designed as a locking lug (9a) and the mechanical counter-interface (9b) as a locking receptacle (9b), wherein the locking lug (9a) in the locking receptacle (9b) can be switched between a coupling position and a release position, and that an acoustic alarm module (6) of the at least one alarm module (5, 6) has a plurality of acoustic openings (14) which are arranged at a distance from one another on a peripheral wall of the coupling housing (7). [2] Fire alarm device (1) according to claim 1, characterized by that the fire alarm device (1) comprises at least two alarm modules (5, 6), wherein one of the at least two alarm modules (5, 6) is designed as an optical alarm module (5). [3] Fire alarm device (1) according to claim 1, characterized by that the coupling housings (7) with the mechanical interface (9a) are each designed as a 2-component injection-molded part. [4] Fire alarm device (1) according to claim 3, characterized by that the coupling housing (7) and the mechanical interface (9a) for switching between the coupling and release positions have different plastic shrinkage dimensions. [5] Fire alarm device (1) according to one of the preceding claims, characterized by that the coupling housings (7) each comprise an electrical coupling device (8) via which the coupling housings (7) can be or are electrically connected. [6] Fire alarm device (1) according to claim 5, characterized by that the electrical coupling devices (8) of the coupling housings (7) to be coupled are designed as an electrical interface (8a) and an electrical counter-interface (8b). [7] Fire alarm device (1) according to one of the preceding claims 2, 5 or 6, characterized by that the optical alarm module (5) has a plurality of light emitters (13) which are arranged at a distance from one another on a peripheral wall of the coupling housing (7). [8] Fire alarm device (1) according to one of the preceding claims, characterized by that the peripheral walls of the coupling housings (7) of the at least one fire sensor module (4) and of the at least one alarm module (5, 6) are flush with one another. [9] Fire alarm device (1) according to one of the preceding claims 2, 5, 6 or 7, characterized by that the coupling housing (7) of the acoustic alarm module (6) forms a wall coupling housing, the coupling housing (7) of the optical alarm module (5) forms an intermediate coupling housing and the coupling housing (7) of the fire sensor module (4) forms an end coupling housing. [10] Fire alarm device (1) according to claim 9, characterized bythat the wall coupling, intermediate coupling and end coupling housings together form a cylindrical shape.

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