阅读说明：本技术 从设计用在易爆区域的至少部分金属外壳传送信号的设备 (Device for transmitting signals from at least a portion of a metal casing designed to be used in an explosive area ) 是由 托马斯·布勒德特 哈拉尔德·朔伊布勒 德克·利尔 安德烈亚斯·凯泽 法比安·本宁格尔 于 2020-03-24 设计创作，主要内容包括：本发明涉及借助于特定波长(λ)的电磁波(3)从被设计用于在易爆区域中使用的至少部分金属外壳(2)传送信号的设备,包括：-外壳(2)；-发射/接收单元(11),该发射/接收单元(11)用于产生和/或接收电磁波(3)；-至少一个主天线(4),该至少一个主天线(4)用于电磁波(3)的外耦合和/或内耦合；-至少一个狭槽形外壳开口(5)；-成型部件,该成型部件由介电数显著大于1的材料制成,并且该成型部件最多以指定深度(T-(波导件))在外壳开口中接合。(The invention relates to a device for transmitting signals from at least a portion of a metal casing (2) designed for use in explosive areas by means of electromagnetic waves (3) of a specific wavelength (λ), comprising: -a housing (2); -transmitting/receivingA receiving unit (11), the transmitting/receiving unit (11) being adapted to generate and/or receive electromagnetic waves (3); -at least one main antenna (4), the at least one main antenna (4) being used for out-coupling and/or in-coupling of electromagnetic waves (3); -at least one slot-shaped housing opening (5); -a profiled part made of a material having a dielectric number significantly greater than 1 and which is at most at a given depth (T) Wave guide ) Engaging in the housing opening.)

1. An apparatus for transmitting signals using electromagnetic waves (3) of a specific wavelength (λ) and based on a housing (2) at least partially formed of metal for use in explosion-hazardous areas, comprising:

-said shell (2), said shell (2) having a defined thickness (D)_{Outer casing}) And a substantially rotationally symmetrical, preferably cylindrical outer contour,

a transmitting/receiving unit (11), the transmitting/receiving unit (11) being arranged in the housing (2) for generating and/or receiving the electromagnetic waves (3),

-at least one main antenna (4), said at least one main antenna (4) being arranged in said housing (2) for out-coupling and/or in-coupling of said electromagnetic waves (3) and transmitting said electromagnetic waves (3) to and from said transmitting/receiving unit (11),

-at least one slot-shaped housing opening (5), said at least one slot-shaped housing opening (5) being realized such that, upon interaction of said at least one slot-shaped housing opening (5) with said main antenna (4), said signal is transmitted into and out of said housing by means of said electromagnetic wave (3), and

-a profiled part (23, 231, 232, 233, 234, 235, 236), which profiled part (23, 231, 232, 233, 234, 235, 236) is made of a material with a relative dielectric number significantly greater than 1 and which profiled part has a protruding slot-shaped region (231) matching the slot-shaped housing opening, through which slot-shaped region (231) the profiled part extends to a predetermined maximum depth (T) into the housing opening_{Wave guide}) Wherein said predetermined depth (T)_{Wave guide}) Is selected such that a sphere or hemisphere (MK) has a diameter which does not contact the profiled part when arranged on the at least one slot-shaped housing opening, wherein the profiled part also has a minimum width (B) which adjoins and surrounds the slot-shaped region_{Wave guide}) In that the profiled part with the enclosing region is pressed against the inner side (202) of the housing in the region enclosing the at least one slot-shaped housing opening, and the minimum width of the enclosing region (232) is realized such that for a gas which complies with the standard IEC60079-1 (6/27 th edition 2014) the volume V ≦ 10cm³When passing through the at least one slot-shaped housing opening from the inside of the metal housing to the outside of the metal housing, the shortest path is at least 3mm, or when 10cm³<V≤100cm³When said shortest path is at least 6mm, or when V>100cm³Said shortest path is at least 10mm, wherein the volume V is defined as the free space enclosed by the entire housing.

2. The apparatus according to claim 1, further comprising a seal (26), the seal (26) being introduced between the slot-shaped region (231) of the profiled component and a housing wall section (203), wherein the slot-shaped region (231) of the profiled component is disposed in the at least one slot-shaped housing opening, the housing wall section (203) defining the slot-shaped housing opening, thereby preventing penetration of dust and/or water.

3. The apparatus of the preceding claim, wherein the seal (26) is introduced into a lateral seat (235) of the housing wall section (203) and/or into a lateral seat (235) of the slot-shaped region (231).

4. Device according to one of the preceding claims, wherein the shaped part is made of plastic, in particular polyethylene.

5. The apparatus as claimed in one of the preceding claims, further comprising a spring steel retainer (24), which spring steel retainer (24) is arranged in the interior of the housing and which spring steel retainer (24) is realized to press the profiled part together with the enclosing region against the inner side of the housing in a region enclosing the at least one slot-shaped housing opening.

6. Apparatus according to the preceding claim, wherein the spring steel retainer (24) has a substantially U-shaped central region (241) as seen in cross section, on both ends of which central region (241) webs (242) are realized which extend outwards, preferably at an angle (a) of more than 45 °, respectively, wherein the webs are dimensioned such that the spring steel retainer rests or is supported on at least two positions or regions of the housing wall (204), wherein the spring steel retainer further has a cutout (243) and the profiled part further has two edges (233), wherein each edge is realized on a long side of the enclosing region, and the cutout and the edges are realized such that the profiled part can be introduced into the cutout and rests with the edges on the spring steel retainer, such that the spring steel retainer presses the profiled part together with the enclosed region (232) against the inner side of the housing.

7. The device according to one of the preceding claims, further comprising a circuit board (6) arranged within the housing (2), the circuit board (6) being realized as a main antenna (4) for out-coupling and/or in-coupling of the electromagnetic waves (3) such that the electromagnetic waves (3) are side out-coupled or in-coupled at a circuit board edge (61), and wherein the circuit board is arranged in the housing (2) such that the circuit board edge (61) is positioned towards the slot-shaped housing opening (5).

8. The device according to the preceding claim, wherein the circuit board (6) is held and arranged by a circuit board holder (25) in the housing such that the circuit board edge (61) is located towards the slot-shaped housing opening (5).

9. Apparatus according to at least the preceding claim, wherein the profiled part (23) has means for holding and/or positioning the circuit board (6), in particular one or more webs (237).

10. The device according to one of claims 8 or 9, wherein the profiled part (23) and/or the circuit board holder (25) are further realized such that the circuit board (6) with the circuit board edge (61) bordering the main antenna (4) is arranged in the longitudinal direction of the at least one slot-shaped housing opening substantially parallel to the Centre Line (CL) of the at least one slot-shaped housing opening (5) and preferably substantially centered in the transverse direction of the slot-shaped housing opening.

11. The device according to one of claims 8 to 10, wherein the circuit board holder (25) and the spring steel retainer are realized relative to each other such that the circuit board holder (25) supports the spring steel retainer in the housing (2) to avoid slipping.

12. Device according to at least one of the preceding claims, wherein the circuit board (6) has at least one light-emitting means (19), in particular an LED, which at least one light-emitting means (19) is arranged on the circuit board edge (61), and wherein preferably the length of the slot-shaped housing opening follows L_{Narrow slot}＝λ/2+n_LED·L_LEDWherein n is_LEDNumber of light emitting devices, L_LEDIs a value of less than or equal to 2 mm.

13. The apparatus according to the preceding claim, wherein the at least one light-emitting device (19) is arranged on the circuit board edge (61), outside the area of the circuit board (6), in particular on the right or left side thereof, directly behind the slot-shaped housing opening (5), and the profiled part (23) has an optical waveguide (236), which optical waveguide (236) is integrated and realized in the profiled part (23) such that an optical signal emitted from the light-emitting device (19) is guided to the slot-shaped housing opening.

14. Device according to at least one of the preceding claims, wherein the at least one slot-shaped housing opening is realized such that the length L of the slot-shaped housing opening_{Narrow slot}λ/2 ± λ/25, and the width B of the slot-shaped housing opening_{Narrow slot}<25mm, preferably B_{Narrow slot}10mm or less, particularly preferably B_{Narrow slot}Less than or equal to 6mm, very particularly preferably B_{Narrow slot}≤4mm。

15. Device according to one of the preceding claims, wherein the housing is realized such that the length L of the housing_{Outer casing}< lambda, preferably L_{Outer casing}< 0.95. lambda, particularly preferably L_{Outer casing}＜0.90·λ。

16. The apparatus according to at least one of the preceding claims, wherein the width B of the slot-shaped housing opening_{Narrow slot}≥1/100·λ。

17. Device according to at least one of the preceding claims, wherein the circumference or perimeter U of the rotationally symmetrical, preferably cylindrical outer contour of the housing_{Outer casing}N λ/4, where N ∈ N.

18. A field device adapter for wireless data transfer into or from an explosion-hazard area, comprising a device according to one of the preceding claims.

19. Field device of an automation technology, comprising a field device adapter according to the preceding claim, wherein the housing (2) has a mechanical connection element at the second end (22) for connecting, in particular screwing, the field device adapter to a cable gland of the field device.

Technical Field

The invention relates to a device for transmitting signals from an at least partially metallic housing using electromagnetic waves of a specific wavelength, a field device adapter for wireless data transmission and a field device for automation technology.

Background

In automation technology, in particular in process automation technology, field devices are frequently used which are used to determine, optimize and/or influence process variables. For recording process variables are sensors, such as fill level measuring devices, flow measuring devices, pressure and temperature measuring devices, conductivity measuring devices, etc., which record the corresponding process variable, fill level, flow, pressure, temperature and conductivity. For influencing the process variable is an actuator, for example a valve or a pump, by means of which the flow of liquid in the pipe section or the filling level in the container can be varied. In principle, a field device refers to all devices that are applied in the vicinity of a process and that transmit or process information relating to the process. For purposes of the present invention, the term field device, and thus also remote I/O, refers generally to a device disposed at the field level. A large number of such field devices are manufactured and sold by Endress + Hauser corporation.

Two-conductor field devices which are connected to a superordinate unit (for example a control unit PLC) via two-conductor lines are still common today in a large number of existing automation plants. Two-conductor field devices are implemented such that measured or actuation values as the main process variable are communicated, i.e. transmitted or transmitted, in an analog manner in the form of a 4mA (milliamp) -20mA signal over a two-conductor line or cable. The HART protocol has gained acceptance for sending all other data, in which case a 4mA-20mA analog current signal is superimposed with a frequency signal of a digital two-conductor signal for data transfer. In the HART protocol, data transfer is based on switching between 1200Hz (hertz) and 2400Hz, with the lower frequency being a logical "0" and the higher frequency being a logical "1". In this way, the slowly variable analog current signal remains unaffected by the frequency superposition. In this manner, the HART protocol combines analog and digital communication.

However, in the course of increasing digitization, it is desirable that data not only be able to be transmitted over two-conductor lines, i.e., purely by wire, but also be able to be wirelessly communicated by electromagnetic waves. For example, it may be desirable to wirelessly communicate data to a database, such as a cloud database, and make it available there, or wirelessly communicate data between a field device and a mobile service unit, for example, to parameterize or configure the field device wirelessly through the mobile service device.

Often used for wireless data transfer are field device adapters through which existing field devices are retrofitted for wireless data transfer. In this case, these field device adapters can be incorporated directly into the two-conductor line. I.e. the field device adapter is actually connected as a separate unit between the superordinate unit and the field device. Alternatively, the field device adapter can also be connected directly in the field device, for example mechanically via a cable gland and electrically with the electronics of the field device.

Typically, field device adapters and field devices are used in areas where there is a risk of explosion. Generally, combustible and explosive materials in the form of gas, vapor, mist or dust may occur in many industrial fields. Important areas in this context are, for example, the coal mining, chemical and petrochemical industries, but also the food industry, milling operations, waste water areas and biogas production. These combustible materials form an explosive atmosphere when mixed with oxygen.

Three prerequisites for an explosion to occur: combustible gases or dust, oxygen, and ignition sources. For the manufacturers of equipment and protection systems, this means that their equipment and plants must be developed and set up to ensure that they do not constitute an ignition source, even in the event of possible failure. For this purpose, so-called ignition protection types have been defined, which establish the structure and circuit technology for the devices used for explosion hazards.

For example, at least a partial metal housing must be used. However, this has the disadvantage that wave radiation for wireless data transmission is generally not possible. Furthermore, additions such as, for example, external rod antennas, which may be attached to field device adapters or field devices to still enable wave propagation, represent a weak point of the housing, and should therefore be avoided.

Furthermore, if the antenna breaks, high field strengths at the base must be prevented, which may exceed the permissible energy density in the explosion-hazard area of the automation plant.

Disclosure of Invention

It is an object of the invention to provide a device that can be used in explosion-hazard areas and still has a high radio range, preferably in all "sky directions", i.e. with as little radio energy as possible concentrated in certain directions. Furthermore, the production of the device should be cost-effective.

This object is achieved according to the invention by a device as defined in claim 1, a field device adapter for wireless data transmission as defined in claim 18 and a field device of an automation technology as defined in claim 19.

The apparatus of the present invention for transmitting signals using electromagnetic waves of a specific wavelength is based on an enclosure formed at least in part of metal for use in an explosion-hazard area, comprising:

a housing having a defined thickness and a substantially rotationally symmetrical, preferably cylindrical, outer contour,

a transmitting/receiving unit arranged in the housing for generating and/or receiving the electromagnetic waves,

at least one main antenna arranged in the housing for out-coupling and/or in-coupling of the electromagnetic waves and for transmitting the electromagnetic waves to and from the transmitting/receiving unit,

-at least one slot-shaped housing opening, which is realized such that, upon interaction with the main antenna, the signal is transmitted into and out of the housing by means of the electromagnetic waves, and

-a profiled part made of a material with a relative dielectric number significantly greater than 1 and having a protruding slot-shaped region matching the slot-shaped housing opening, through which the profiled part extends to a predetermined maximum depth in the housing opening, wherein the predetermined depth is selected such that a sphere or hemisphere (MK) has a diameter which is not in contact with the profiled part if arranged on the at least one slot-shaped housing opening, wherein the profiled part also has a region which adjoins the slot-shaped region and surrounds a minimum width of the slot-shaped region, wherein the profiled part with the surrounding region is pressed against the inside of the housing in the region surrounding the at least one slot-shaped housing opening, and the minimum width of the surrounding region is realized such that for a gas which conforms to the standard IEC60079-1 (6.27.2014), when the volume V is less than or equal to 10cm³While passing through said at least one slot-shaped housing opening from inside said metal housingThe shortest path to the outside of the metal casing is at least 3mm, or when 10cm³<V≤100cm³When said shortest path is at least 6mm, or when V>100cm³Said shortest path is at least 10mm, wherein the volume V is defined as the free space enclosed by the entire housing.

According to the invention, the preferably plastic molded part, hereinafter also referred to as a waveguide, is particularly protected, wherein the part of the waveguide extending into the slot-shaped housing opening is retracted, so that a ball allowed to fall on the slot-shaped housing opening according to the specifications of the shock resistance test does not damage the waveguide.

An advantageous embodiment of the inventive device further comprises a seal which is introduced between the slot-shaped region of the profiled element and a housing wall section, wherein the slot-shaped region of the profiled element is arranged in the at least one slot-shaped housing opening, the housing wall section defining the slot-shaped housing opening, so as to prevent penetration of dust and/or water. In particular, this embodiment may provide that the sealing element is introduced into a lateral seat of the housing wall section and/or into a lateral seat of the slot-shaped region.

A further advantageous embodiment of the device according to the invention provides that the shaped part is made of plastic, in particular polyethylene.

A further advantageous embodiment of the device according to the invention further comprises a spring steel retainer which is arranged in the interior of the housing and which is realized to press the profiled section together with the enclosing region against the inner side of the housing in a region enclosing the at least one slot-shaped housing opening. In particular, this embodiment may provide that the spring steel retainer has a substantially U-shaped central region as seen in cross-section, on both ends of the central region are realized webs respectively which preferably extend outwards at an angle of more than 45, wherein the web is dimensioned such that the spring steel retainer rests or is supported on at least two locations or regions of the housing wall, wherein the spring steel retainer further has a cutout and the profiled section further has two edges, wherein each edge is realized on a long side of the enclosing region, and the cut-out and the edge are realized such that the profiled part can be introduced into the cut-out and rests with the edge on the spring steel retainer, such that the spring steel retainer presses the profiled part together with the enclosed region against the inner side of the housing.

A further advantageous embodiment of the device of the invention further comprises a circuit board arranged within the housing, which circuit board is realized as a main antenna for out-coupling and/or in-coupling of the electromagnetic waves, such that the electromagnetic waves are out-coupled or in-coupled laterally at a circuit board edge, and wherein the circuit board is arranged in the housing such that a circuit board edge is positioned towards the slot-shaped housing opening. In particular, this embodiment may provide that the circuit board is held and arranged by a circuit board holder in the housing such that the circuit board edge is positioned towards the slot-shaped housing opening.

In particular, according to this embodiment, the main antenna may be realized in the form of a planar structure, in particular in the form of a conductive track on the circuit board and arranged at the edge of the circuit board, wherein the conductive track may consist of two substantially parallel subsections which are connected together by a 180 ° arc.

Further according to an embodiment, the circuit board may comprise an HF shielding fence, preferably realized as at least one row of through holes, wherein the HF shielding fence may be realized at least on the same side of the circuit board as the main antenna, and preferably may form a rectangular area adjoining the first side of the circuit board on an edge of the circuit board, in which rectangular area the main antenna is arranged.

Alternatively or additionally, according to this embodiment it may also be provided that the circuit board comprises a HF shielding metal sheet, preferably with metal-containing electrical components, such as coils, capacitors, transformers, terminals, etc., and wherein the HF shielding metal sheet is realized on the opposite side of the circuit board to the main antenna, and/or that the HF shielding metal sheet and/or HF shielding fence is arranged on the circuit board such that the main antenna is arranged between the HF shielding metal sheet or the HF shielding fence and the circuit board edge.

A further advantageous embodiment of the device according to the invention provides that the profiled section has means for holding and/or positioning the circuit board, in particular one or more webs.

A further advantageous embodiment of the inventive device provides that the profiled section and/or the circuit board holder are further realized such that the circuit board with the circuit board edge bordering (bordering) the main antenna is arranged in the longitudinal direction of the at least one slot-shaped housing opening substantially parallel to the center line of the at least one slot-shaped housing opening and that the circuit board edge is preferably substantially centered in the transverse direction of the slot-shaped housing opening.

A further advantageous embodiment of the inventive device provides that the circuit board holder and the spring steel retainer are realized with respect to each other such that the circuit board holder supports the spring steel retainer in the housing to avoid slipping and/or displacement.

A further advantageous embodiment of the inventive device provides that the circuit board has at least one light-emitting means, in particular an LED, which is arranged on the circuit board edge, and wherein preferably the length of the slot-shaped housing opening follows L_{Narrow slot}＝λ/2+n_LED·L_LEDWherein n is_LEDNumber of light emitting devices, L_LEDIs a value of less than or equal to 2 mm. In particular, this embodiment can provide that the at least one light-emitting device is arranged on the circuit board edge, outside the circuit board area, in particular on the right or left side thereof, directly behind the slot-shaped housing opening, and that the molding member has an optical waveguide which is integrated and realized in the molding member such that an optical signal emitted from the light-emitting device is guided to the slot-shaped housing opening.

Hair brushA further advantageous embodiment of the lighting device provides that the at least one slot-shaped housing opening is realized such that the length L of the slot-shaped housing opening is_{Narrow slot}λ/2 ± λ/25, and the width B of the slot-shaped housing opening_{Narrow slot}<25mm, preferably B_{Narrow slot}10mm or less, particularly preferably B_{Narrow slot}Less than or equal to 6mm, very particularly preferably B_{Narrow slot}≤4mm。

A further advantageous embodiment of the device according to the invention provides that the housing is realized such that the length L of the housing_{Outer casing}< lambda, preferably L_{Outer casing}< 0.95. lambda, particularly preferably L_{Outer casing}＜0.90·λ。

A further advantageous embodiment of the device according to the invention provides that the width B of the slot-shaped housing opening_{Narrow slot}≥1/100·λ。

A further advantageous embodiment of the device according to the invention provides that the circumference or perimeter U of the rotationally symmetrical, preferably cylindrical outer contour of the housing_{Outer casing}N λ/4, where N ∈ N.

The invention also relates to a field device adapter for wirelessly transmitting data to or from an explosion-hazard zone, comprising a device according to one of the above-described embodiments.

The invention also relates to an automation field device comprising a field device adapter according to the above-described exemplary embodiments, wherein the housing has a mechanical connection element at the second end for connecting, in particular screwing, the field device adapter to a cable gland of the field device.

Drawings

The invention will now be explained in more detail on the basis of the drawings, which are shown below:

figure 1 is a schematic diagram of an apparatus for transmitting signals using electromagnetic waves of a particular wavelength,

figure 2 is a longitudinal cross-sectional view of the apparatus shown in figure 1,

figure 3 is a detailed view of the cross section of the device and the slot-shaped housing opening,

fig. 4 is a schematic view of the slot-shaped housing opening and the circuit board, to illustrate the relative arrangement of the two,

figure 5 is a schematic diagram of an additional embodiment of the apparatus,

fig. 6 is the HF circuit paths U1 and U2 shown in perspective in fig. 5, in this case shown in plan to illustrate the operation of the delay element,

figure 7 is a perspective view of the apparatus of the present invention,

fig. 8 is a perspective view of the apparatus of the present invention, with portions of the housing removed,

figure 9 is a cross-section of the apparatus of the invention,

fig. 10 is a detailed view of the opening of the slot-shaped housing to illustrate an embodiment of the wave guide according to the invention, and

fig. 11 is a cross-section of a shaped part or waveguide.

Detailed Description

The device shown in fig. 1 comprises a housing 2, which is substantially made of metal, preferably stainless steel. However, the housing 2 may alternatively be made of plastic and preferably lined on the inside with a metal layer. In this case, the housing 2 is geometrically realized such that it has a substantially rotationally symmetrical closed form on the outside. For example, the housing as shown in fig. 1 may have a substantially cylindrical outer contour. Of course, the housing may have openings, such as electrical vias 13, 14 and slot-shaped openings 5. Thus, the ends 21, 22 of the cylindrical housing 2 may provide cable passages 13, 14, through which cable passages 13, 14 cables 1a, 1b, each having at least one signal line, extend into the housing 2 or out of the housing 2. The cables 1a, 1b may comprise two-conductor lines, as are commonly used in process and/or manufacturing automation, for example. Alternatively, in one of the two end faces, a mechanical connection element can be provided for connecting the device, in particular for screwing it to a cable gland of the field device 7.

In the housing 2, a circuit board 6 is arranged, to which the cables 1a, 1b with the signal lines lead or from which the cables lead or lead. The circuit board 6 includes a transmission/reception unit 11 for generating and receiving electromagnetic waves. The transmit/receive unit 11 may be an HF modem, for example implemented in the form of a chip. The circuit board 6 also comprises a main antenna 4 for out-coupling the generated electromagnetic waves and for in-coupling and transmitting the received electromagnetic waves, and may additionally also comprise a matching structure 15. The matching structure 15 may be implemented as part of the transmit/receive unit and/or as part of the main antenna. Alternatively, the matching structure 15 may also be realized as a separate component of the circuit board 6.

The transmission/reception unit 11 is adapted to generate and receive electromagnetic waves in the frequency band of 2.4GHz, so that signals transmitted by means of a cable or a two-conductor line can also be transmitted wirelessly by the device via bluetooth (in the given case also via bluetooth low energy consumption) or one of the variants described above.

The housing 2 comprises a housing having a length L_{Narrow slot}Of a slot-shaped opening 5 of which the length L is_{Narrow slot}May correspond to about half the wavelength lambda/2 of the electromagnetic wave. Width B of slot-shaped opening 5_{Narrow slot}Can be selected as<25mm, preferably B_{Narrow slot}10mm or less, particularly preferably B_{Narrow slot}Less than or equal to 6mm, very particularly preferablyThe slot-shaped housing opening 5 may have a frequency of 2.4GHz and a wavelength of about λ 122.36mm, for example, in the rangeHas a length and a width of aboutThe slot-shaped opening 5 has no electrical connection to the circuit board 6 and is radiated by the main antenna 4 disposed within the housing 2. Further, the housing length L_{Outer casing}And may be selected to be less than the wavelength 1 · λ. Preferably, the housing length L_{Outer casing}Can be used for<0.95. lambda., particularly preferably L_{Outer casing}<0.90. lambda. Thus, on the one hand, the housing does not act as a resonator at the operating frequency, and on the other hand, no hollow conductor propagation is possible inside the cylindrical housing 2.

FIG. 2A cross-section of the apparatus shown in figure 1 is shown. Fig. 2 includes a side view of the circuit board 6, the circuit board 6 being disposed in the housing 2. The housing comprises two end faces 21, 22, wherein in each end face a cable passage 13, 14 (comprising a cable and a retainer) can be placed. The diameter D of the electrical path may be selected so that no high frequency energy is radiated laterally_{Cable with a protective layer}<1/4 lambda. Fig. 2 additionally shows a main antenna 4, which is also referred to as a radiating structure. The main antenna 4 forms an antenna together with the slot-shaped housing opening 5 and the housing 2. Furthermore, in order to be able to test the circuit board 6 before mounting, the main antenna 4 can also be implemented such that it has at least a slight antenna effect at least in the near field 8 even without a housing.

Fig. 3 shows a section of the device shown in fig. 1 and 2 on the left, in the case of fig. 1 and 2 the circuit board 6 can preferably be realized such that the circuit board thickness D_PCB>B_{Narrow slot}2 such that, when the circuit board 6 with the circuit board edge 61 is oriented on the midpoint MP of the diameter of the cylindrical housing 2, the circuit board 6 at least partially bridges the slot-shaped housing opening 5, in particular at least half, with the main antenna 4 bordering on the circuit board edge 61.

Fig. 3 shows a further detailed view on the right to illustrate a possible arrangement between the circuit board 6 and the slot-shaped housing opening 5. Furthermore, the circuit board 6 may be arranged such that the circuit board edge 61 is adjacent to the main antenna 4, parallel to the centre line CL of the slot-shaped housing opening 5.

Fig. 4 likewise shows a schematic illustration of the slot-shaped housing opening 5 and the circuit board 6 in order to describe an embodiment of the circuit board 6 in more detail.

The circuit board 6 may thus comprise an HF shielding fence 16 consisting of through holes 17. In this case, the through holes 17 may be realized such that they extend from a first side (top) 63 of the circuit board to a second side (bottom) 64 of the circuit board. This means that the through-hole 17 may extend through all layers of the circuit board 6. Alternatively, the through hole 17 may also be realized to extend only from the first side of the circuit board 63 to the intermediate circuit board layer. The HF shielding fences 16 can preferably be implemented in two rows in order to achieve a maximum fence effect also in the case of small, cost-effective underground produced through-holes and to greatly reduce the influence of other elements in the housing, such as screwed-in cables. Due to the HF shielding fence 16, a substantially rectangular area 65 may be defined on the first side of the circuit board 63, which is limited to one side of the circuit board edge 61.

Furthermore, the HF shielding fence 16 can be supplemented by an HF shielding metal sheet 18, which is arranged on the second side (back side) 64 of the circuit board. Fig. 4 shows the arrangement of the HF shielding metal sheet on the rear side of the circuit board with dashed lines. The HF shielding metal sheet 18 can fulfill another function on the circuit board 6 in addition to shielding HF waves. For example, the HF shielding metal sheet 18 may comprise metal-containing electrical components such as, for example, coils, capacitors, transformers, terminals, etc., wherein the HF shielding metal sheet 18 is preferably electrically connected with the HF shielding fence 16. Alternatively, other metal components on the circuit board 6, components with a high metal content (such as coils), or material components with a high DK (such as flat SMD capacitors) may be used as the HF shielding metal sheet 18.

Furthermore, as shown in fig. 4, the circuit board 6 may comprise a transmitting and/or receiving unit 11, a main antenna 4, a matching structure 15 for impedance matching between the transmitting and/or receiving unit 11 and the main antenna 4, and two LEDs 19. These LEDs may be used to emit light signals, for example to signal the status of the device. In order to be able to see the LEDs on the outside of the housing 2, the length of the slot-shaped housing opening can be enlarged in a range specific to the LEDs. For example, the length of the slot-shaped housing opening may be lengthened by one millimeter (1mm) to the left or right. This means that in this case the length of the slot-shaped housing openingWherein n is_LED2mm and L_LED1 mm. Due to the interference effect of the housing thickness, the elongated slot-shaped housing opening does not behave like an elongated incision, but rather resembles an ellipse in HF technology, so that it can be lengthened by 1mm to 2mm at both ends without major influence.

As is apparent from fig. 4, the main antenna 4 may be arranged in a rectangular area 65. The main antenna 4 may preferably be realized in the form of conductive tracks 41, 42, 43, 44, which may have an active part 42 and a passive part 41. The active and passive sections 41, 42 may be connected together by a 180 arc segment 43 so that the conductive trace has a certain total length to act as a resonator at the center frequency. Finally, the length may be terminated by a circular region 44 in order to reduce the quality of the resonator and in fact be sufficient to keep the transient ringing below the path length of the Viterbi algorithm (Viterbi algorithm) for a particular transmitting and/or receiving unit.

In this case the active part 42 acts as the actual "radiator", wherein the energy of the passive part 41 can be conducted out through the ground area 181 of the HF shield strip 18, wherein the HF shield strip 18 extends from the HF shield fence 16 to the circuit board bottom surface 64, so that the passive component 41 does not act as a "radiator". The interaction of the active part 41 and the passive part 42 can form a radiator which would otherwise extend over the entire width of the slot-shaped housing opening 5 to a width which is slightly narrower than the slot-shaped housing opening 5. In this way, interference effects on the outer edge of the slot-shaped housing opening can only partially influence the radiator in a defined manner, and radiation through the slot-shaped housing opening is still possible. The ground region 181 may in particular have an L-shaped configuration in the side contour. In addition, to improve the efficiency of the draining away (drain away), structures may be placed on the bottom of the circuit board 64. The structure may also comprise, for example, HF shielding metal sheets or other metal components. In this way, the residual power can be deflected and radiated to the slot-shaped housing opening 5. This additionally leads to a better antenna matching (-20 … 30dB, in the range of + -5% around the center frequency) and, in addition, to an additional stability of the production tolerances. The radiation of the necessary 180 ° arc 43 can be matched to an impedance value just above zero ohms with the structure 20 which can likewise be arranged in the rectangular region 65 of the circuit board, in order then to be transmitted to the HF shielding rail 16. For example, the structure may have a saw-tooth profile in plan view of the circuit board.

The circuit board 6 can be oriented in the housing 2 such that the outer through-holes continuing to the circuit board edge 61 can each have a separation of approximately 1mm from the edge of the slot-shaped housing opening at the slot width in the longitudinal direction.

Fig. 5 shows a schematic view of another embodiment of the device, in which the housing 2 can have an outer contour which is 4 times rotationally symmetrical. In order to be able to apply the device in areas where there is a risk of explosion (so-called explosion-hazard areas, abbreviated to "Ex areas"), the slot-shaped openings 5 are filled with another material than air, in particular a non-conductive material, such as glass. Plastics, in particular polyethylene, have proven particularly suitable as non-conductive material.

Additionally or alternatively, the housing may be geometrically realized such that at least two HF external circuit paths U1, U2 measured in two large-scale spatial directions (preferably HF external circuit paths measured in each spatial direction of the housing) both correspond to integer multiples of half wavelength λ/2 of an electromagnetic wave at which signals are emitted, for example as shown in fig. 5. In this case, the HF circuit paths can be measured or established such that they pass through the slot-shaped housing openings, respectively. Preferably, the HF circuit paths can be established such that they extend through the center of the slot-shaped housing opening.

To further detail the HF circuit paths U1 and U2, which are illustrated in perspective in fig. 5, they are again shown in fig. 6, this time in one plane. Fig. 6 shows that each HF circuit path U1 and U2 passes through the slot-shaped housing opening 5.

In order to locally extend the round trip time of the wavelength, i.e. introduce a delay, one or more circuit delay elements 10 may be implemented on the outer surface of the housing 2. The placement of two delay elements 10 on the outer surface of the housing is shown by way of example in fig. 5. The delay element 10 shown in fig. 5 may be implemented as a trench-shaped element. However, another option is also one or more elements in the form of dots, which may be realized in another material than the housing 2, in particular a dielectric material or a high-frequency metamaterial. By suitable positioning, the HF circuit path can be deliberately changed, in particular enlarged, in one or more spatial directions. It should be noted that the HF current depends on the structural size of the delay elements of the circuitThe path is typically slightly smaller than the (mechanical) path, such as U_{Outer casing}Because the electromagnetic wave partially jumps over a particularly small structure and, by interaction of the E and H fields, a slight shortening of the whole occurs.

Figure 7 shows a schematic diagram of the apparatus of the present invention. The apparatus comprises: a metal housing (wherein the housing is substantially rotationally symmetrical with respect to the outer contour and preferably with respect to the central axis except for the slot-shaped housing opening 5); the metal shell has a defined thickness D_{Outer casing}(ii) a A slot-shaped housing opening 5; and cable passages 13, 14. Furthermore, the housing 2 is embodied such that it can be used in explosion-hazard areas, in particular in gas explosion-hazard areas. For this purpose, the design of the housing meets the requirements of the ignition protection type "pressure-proof packaging" (designated Ex-d) of the international standard IEC 600798-1 (6-month-27-day version 2014). In the case of this type of ignition protection, the propagation of an explosion can be prevented. Here, protection relies mainly on structural measures and therefore does not in fact prevent the penetration of gases, and in the event of ignition inside the casing, the latter can withstand the pressure of the explosion and the ignition does not propagate to the outside. In order to meet the requirements of the ignition protection type "pressure-resistant encapsulation", the metal housing 2 has in the simplest case a corresponding minimum thickness, for example 3 mm. However, the presence of the slot-shaped housing opening 5 represents a structural challenge that increases the satisfaction of the ignition protection type "pressure-resistant packaging" requirements.

Fig. 8 omits the housing to show the internal structure of the apparatus of fig. 7. In principle, the device consists of separate parts which are brought together, for example plugged together, in order to form the device of the invention.

As shown in fig. 8, in the region of the slot-shaped housing opening 5, there is a dielectric constant (dimensionless number) significantly greater than 1 (epsilon)_r>1) Is particularly transparent to electromagnetic radiation in the visible range, and is therefore also referred to hereinafter as a waveguide 23. For example, the wave guide 23 may be made of plastic, in particular Polyethylene (PE). Alternatively, the waveguide 23 may be made of glass. Due to the selection of a relative dielectric significantly greater than 1Number epsilon_rShortening of the wavelength λ is achieved. The wave guide 23 is realized such that it has a protruding slot-shaped region 231, which protruding slot-shaped region 231 extends into the slot-shaped housing opening 5 to a predetermined depth T in the case of an application of the housing 2_{Wave guide}. Furthermore, the waveguide 23 comprises a region 232 having a defined minimum width B_{Wave guide}And surrounds the slot-shaped region 231 on all sides. In this case, the minimum width is chosen such that when the volume V.ltoreq.10 cm³The shortest path from the inside to the outside of the slot-shaped housing opening of a metal housing complying with the standard IEC60079-1 (6 month 27 th version 2014) is at least 3mm, or when the volume is 10cm³<V≤100cm³When in range, the shortest path is at least 6mm, or when volume V>100cm³This shortest path is at least 10mm, wherein the free space enclosed by the entire housing is defined as the volume V. In a particularly preferred embodiment, the minimum width defined is 6 mm.

Figure 9 shows a cross section of the apparatus of the present invention. As is evident from fig. 9, the outer surface of the enclosing section 232 is matched to the housing wall, so that the enclosing section 232 in the mounted state lies as flush as possible against the interior of the housing 2. According to a corresponding embodiment of the wave guide 23, the wave guide 23 has a substantially oval profile in plan view, wherein two edges 233 are also provided as contact areas in order to mechanically connect the wave guide 23 to the housing 2. The two edges 233 are attached to the enclosed region 232 on the long side of the waveguide. By means of the edge 233 the wave guide 23 in the mounted state can be pressed against the inside of the housing by the spring steel retainer 24. In order to achieve a force distribution which is as uniform as possible and a pressing of the wave guide 23 against the surface facing the interior of the housing 2, the surface section of the surrounding region 232 is matched to the surface section of the housing interior around the slot-shaped housing opening 5. This means that the waveguide 23 has a substantially curved profile in cross-section.

In order to avoid the penetration of dust and/or water, the projecting slot-shaped region 231 of the waveguide 23 comprises, as shown in fig. 9, a seat 235 for the seal 26 on the side surface facing the housing wall in the mounted state. Provided as a seal can be, for example, a surrounding oval ring, which is introduced into the seat 235 in the installed state.

Fig. 10 shows a detailed view of the slot-shaped housing opening 5 to illustrate an embodiment of the wave guide 23 according to the invention. According to the invention, the protruding slot-shaped region 231 of the wave guide 23 is realized such that the protruding slot-shaped region 231 extends in the mounted state to a maximum predetermined depth T in the slot-shaped housing opening 5_{Wave guide}Wherein the maximum predetermined depth T_{Wave guide}Is selected such that the ball or hemisphere MK, when it lands on the slot-shaped housing opening, does not just touch the slot-shaped region introduced into the slot-shaped housing opening 5. Fig. 10 schematically shows a sphere designated with reference MK. In particular, hardened steel balls with a diameter of 25mm are suitable as spheres or hemispheres. The impact resistance test is performed in particular according to the international standard IEC 60079-0 (12 months and 13 days version 2017).

In order to mechanically fix the wave-guide 23 to the housing 2, more specifically to the inner surface of the housing 2, a spring steel retainer 24 is provided for pressing the wave-guide 23 against the inside of the housing 2. For this purpose, the spring steel retainer 24 is essentially U-shaped in cross section in the central region, at the two ends of which webs 242 project at an angle of approximately 90 °, so that the spring steel retainer bears on the housing wall in at least two positions. For the positioning of the wave guide, the spring steel retainer comprises in the central area a cut-out realized such that the wave guide can be introduced into the cut-out, and the wave guide 23 is located on the edge of the cut-out 243 flush with the two edges 233.

In order to influence the wave propagation as little as possible, the cut-out 24 of the spring steel retainer 24 is realized such that its length L_IncisionIs significantly larger than the width B of the slot-shaped housing opening_{Narrow slot}Or, in the case where the light emitting devices (e.g., LEDs) are provided on the circuit boards on the right and left sides of the HF shielding fence 16, respectively, the width of the cutout is sufficiently larger than the interval between the two light emitting devices. About the width B of the cut_IncisionThe spring steel retainer 24 is realized such that the width matches the inner diameter of the housing 2, wherein the width is preferably selected to be as large as possibleMay be large.

The spring steel retainer 24 is held in the housing 2 on a plastic molded part 25 which at the same time serves as a support for the circuit board 6. The plastic molded part 25 is likewise realized in such a way that it has a surface contour which matches the surface contour of the housing interior. The plastic molded part 25 is realized such that, in the mounted state in the longitudinal direction, the circuit board 6 with the circuit board edge 61 bordering the main antenna 4 is positioned parallel to the center line CL of the slot-shaped housing opening 5. Furthermore, as shown in fig. 3, the circuit board may be arranged in a transverse direction of the slot-shaped housing opening such that the circuit board edge 61 is substantially centered. For accurate positioning of the circuit board edge 61, the wave guide 23 may have one or more fins 237, which hold and/or position the circuit board 6. The fins 237 may be realized, for example, in the form of elongated, U-shaped cross-sectional grooves into which the circuit board 6 is inserted.

Fig. 11 shows a cross-section of a portion of a shaped member or waveguide 23 to illustrate another embodiment of the apparatus of the present invention. In this case, the waveguide 23 is implemented such that it contains an internal optical waveguide 236, through which internal optical waveguide 236 an optical path OP is provided for the optical signal from the entrance to the emergence point or emergence region. As an example, three different light paths are shown in fig. 11. Since the optical waveguide 236 is formed in the waveguide, the LEDs can be arranged on the circuit board 6 such that they need not be arranged directly behind the slot-shaped housing opening 5, but can be arranged on the circuit board 6 outside the area that is concealed by the slot-shaped housing opening. Via the optical waveguide, the optical signal is then guided from the point of incidence or region directly through the light-emitting device to the emergence point or the emergence region. In this case, the emergence points or emergence regions can be located, in particular, in the region in which the length of the slot-shaped housing opening is increased by the LEDs. For example, as shown in the example in fig. 11, in the case where two light emitting devices are provided on the circuit board, the slot-shaped housing opening may be lengthened left and right by a length of about one millimeter (1mm), and an optical signal may be guided from the light emitting device 19 to these regions via the optical waveguide 236.

List of reference numerals

1a, 1b cable

2 outer cover

201 free space inside the housing

202 inside the outer shell

203 shell wall segment

204 region of the housing wall against which the spring steel retainer bears

21 first end of the housing

22 second end of the housing

23 shaped part or waveguide

231 slot-shaped area

232 area of enclosure

233 edge

234 surface profile of the wave guide

235 side sealing seat

236 optical waveguide

237 webs for fixing and/or positioning circuit boards

24 spring steel retainer

241U-shaped central region

242 web

243 incision

25 Plastic molded part, Circuit Board holder

26 seal

3 electromagnetic wave

4 main antenna

41 passive part of a conductive track

42 active part of conductive track

180 arc segment of 43 conductive trace

44 circular area of conductive trace

5 Slot-shaped housing opening

6 Circuit Board

61 edge of circuit board

62 edge of circuit board

63 first side of circuit board

64 second side of the circuit board

65 rectangular region

7 field device

8 near field

9 far field

10-circuit delay element

11 transmitting/receiving unit

12 electrically non-conductive material

13 Cable channel for cable access

14 Cable passage for cable exit

15 matching networks, or structures

16 HF shielding fence

17 through hole

18 HF shielding metal sheet

181 ground region extending from shield metal sheet

19 light emitting device, in particular LED

20 impedance matching structure

T_{Wave guide}The wave-guide extends with its slot-shaped region to the slot-shaped housing opening

Depth of (5)

D_{Cable with a protective layer}Diameter of cable passage

L_IncisionLength of waveguide cut

L_{Outer casing}Length of the housing

L_{Narrow slot}Length of slot-shaped housing opening

B_IncisionWidth of waveguide cut

B_{Narrow slot}Width of slot-shaped housing opening

B_{Wave guide}Minimum width of the enclosing region

D_{Outer casing}Thickness of the outer shell

U_{Outer casing}Perimeter of the housing

D_PCBThickness of circuit board

Wavelength of lambda electromagnetic wave

External path around U1, U2 housings

Center of MP case

MK spheres, or hemispheres

Center line of ML slot-shaped shell opening

ε_rRelative dielectric constant (dimensionless unit)

Angle of alpha extending web

U1, U2 HF circuit paths

OP optical path