EP3928390A1

EP3928390A1 - Protective housing in explosion-protection-type pressure-proof encapsulation

Info

Publication number: EP3928390A1
Application number: EP20705195.4A
Authority: EP
Inventors: Elena Kondrus; Bernd Limbacher; Jürgen Schmitt; Helmut Würz
Original assignee: R Stahl Schaltgeraete GmbH
Current assignee: R Stahl Schaltgeraete GmbH
Priority date: 2019-02-22
Filing date: 2020-02-14
Publication date: 2021-12-29
Also published as: US20220184435A1; DE102019104616A1; CN113424382A; WO2020169471A1; CN113424382B

Abstract

The invention relates to a protective housing (10) in explosion-protection-type pressure-proof encapsulation. Preferably at least one device (19, 36, 38, 39) for reducing explosive pressure is associated with the housing (10). The housing (10) comprises a first housing part (11) having a first sealing surface (13) and a second housing part (12) having a second sealing surface (14), wherein, when the housing (10) is in the closed pressure-proof state, a resilient seal (32) is held between the first sealing surface (13) and the second sealing surface (14) so as to be elastically deformed, and, as a result, closes the space (26) between the first sealing surface (13) and the second sealing surface (14) in a flame-proof manner in the event of an explosion inside the housing (10). The flame-proof arrangement according to the invention can replace a planar gap between, for example, a surface of a cover and a surface of a housing part, which gap requires conformity to relatively narrow manufacturing tolerances.

Description

Protective housing in the explosion protection type

pressure proof encapsulation

The invention relates to a protective housing in the explosion protection type flameproof enclosure.

Housings are known from the prior art, which are formed according to the explosion protection type of flameproof enclosure. This allows the accumulation of an explosive gas mixture within the housing and an explosion of the same due to ignition sparks formed by an electrical operating device in the housing. Depending on the degree of protection, it is also permissible that gas or particles can penetrate through gaps from the inside of the housing during the explosion, where there is a potentially explosive atmosphere. However, depending on the type of explosion protection, it must be ruled out that the gas is so hot or the particles are so hot or glowing that the explosive atmosphere outside the housing can be ignited.

DE 10 2010 016 782 A1 describes a pressure relief device for flameproof enclosures. This is designed to be arranged in a housing part and to reduce the size of the resulting pressure peaks even if an explosive reaction occurs in the interior, in that the resulting gases can flow out of the housing quickly and easily through the pressure relief device. From DE 34 36 300 C2 a device housing with an explosion-proof chamber is known. The housing has a casing as a first housing part and a cover as a second housing part. The jacket and cover have flanges in order to produce a flange connection between the jacket and the cover. Gaps through which gas or particles can escape from the interior of the housing to the outside in the event of an explosion are permitted between the flanges. However, these are dimensioned so that a gas ignited within the cavity of the housing cools sufficiently before it leaves the housing through gaps between the flanges. A log device can be arranged between the flanges in order to prevent moisture from entering the housing.

[0005] From DE 26 17 965 B2 a housing designated as pressure-resistant is known which has a housing lower part and a housing upper part. The two parts form a space, which is referred to as the gap. A seal is arranged at the gap between the upper housing part and the lower housing part. This is used together with spring elements to hold together the lower part of the housing with the upper part of the housing. The spring elements are arranged in the space. The gap is filled with casting resin. It is stated that by pouring the gap with casting resin, a pressure-resistant housing will be obtained, which is designed without a gap.

DE 10 2007 003 009 A1 describes a method for producing fluid-tight housings and a fluid-tight housing. The housing has a base part and a plate-like cover as well as a wing surfaces of the base part and cover that face one another and are arranged Nete seal for fluid-tight sealing of the housing interior. Base part and cover are fastened to one another in a prestressed manner, so that the elastic seal is deformed. This prevents gas from reaching an ignition source located inside the fluid-tight housing from the surroundings of the housing.

From DE 10 2013 111 374 A1 an explosion-proof arrangement for electrical and / or electronic components is known. The arrangement has a carrier and a cover body. The cover defines at least one receiving chamber for the components. Between the cover body and the carrier, an elastic coupling element is arranged which completely encloses the opening in the cover body. If the cover body and the carrier are connected by means of a force-fitting and / or form-fitting connection, the coupling element between the cover body and the carrier is elastically deformed. With the explosion-proof arrangement, the requirements should be able to be met as they are defined for an encapsulation (Ex-m) or a flameproof enclosure (Ex-d). With encapsulation (Ex-m), an explosive atmosphere is excluded from the interior of a housing.

DE 1 801 062 A discloses a pressure-resistant housing made of sheet steel parts connected by welding.

In order to contact electrical equipment within a housing of protection type flameproof enclosure, a housing part can have a receiving opening, for receiving a line or a line bushing. An explosion-proof gap (flameproof gap) can be formed between the opening and the duct, which can be designed as a cylindrical or threaded gap.

The object of the present invention is to provide an improved concept for a housing of the protection type pressure-tight encapsulation.

[0011] This object is achieved with a protective housing according to claim 1:

The protective housing according to the invention (hereinafter also just called housing) in the explosion protection type pressure-tight encapsulation has a first housing part with a first sealing surface and a second housing part with a second sealing surface. A device for reducing explosion pressure is preferably assigned to the housing. An elastic seal is held elastically deformed between the first sealing surface and the second sealing surface and thereby closes the space between the first sealing surface and the second sealing surface in a flame-proof manner in the event of an explosion inside the housing.

The sealing body itself is free through gap and consequently impermeable to explosion gas. There are no paths through the sealing body through gaps, pores or other passages which would allow gas - not even gas cooled below an ignition temperature of the atmosphere - to pass through the sealing body in the event of an explosion. This does not mean that the sealing body or the arrangement of the sealing body between the sealing surfaces must be diffusion-tight.

By means of the elastically deformed sealing body is the separation point between the first housing part and the second If an explosion occurs, the housing part is closed at least to such an extent that any remaining explosion gases passing through the separation point are cooled to such an extent that they cannot ignite an explosive atmosphere in the housing either. The absence of passage gaps in the seal body goes beyond this requirement for a flameproof closure of the separation point, because gaps in the seal body, if any, are closed even further than would be required for flameproof safety.

In the protective housing according to the invention, for example, a shallow gap, as is provided in the prior art for pressure housings of the explosion protection type "flameproof enclosure", is replaced by an arrangement of an elastic sealing body between two sealing surfaces, as proposed according to the invention While a flameproof flat gap is defined between the cover and the housing body in the prior art, in embodiments according to the invention the space between the sealing body and the first housing part is at least narrowed to such an extent that it is secured against flammable ignition and between the sealing body and the second housing part is narrowed at least so far that it is secured against ignition breakdown. Gaps that may remain between the sealing body and the first housing part and between the sealing body and the second housing part fill the gap width e and gap length meet the requirements for flameproof Ex gaps, for example the EN 6079-1 standard. This means that there is no need to maintain a close manufacturing tolerance, as is the case for manufacturing a separation point between Lid and housing body, which forms a flat gap, is required.

Of course, if no explosion occurs, the seal can also serve to prevent moisture from entering through the separation point between the first sealing surface and the second sealing surface. The main task of the seal, however, is to keep the separation point flameproof in the event of an explosion.

Examples of further advantageous embodiments of the invention and examples of preferably present features are described below:

In preferred embodiments, the second

Housing part has a further second sealing surface and the housing has a third housing part with a third sealing surface, wherein - in the pressure-tight closed state of the housing - another elastic sealing body is elastically deformed between the further second sealing surface and the third sealing surface and thus the space between tween the further sealing surface and the third sealing surface closes in a flameproof manner in the event of an explosion inside the housing.

[0019] The second housing part can be an intermediate frame. One or more cover parts can be attached to the intermediate frame, preferably hinged, which can form third housing parts of the housing.

Preferably, the connection between the first housing part and the second housing part and / or between the second housing part and the third housing part, if available, non-destructive detachable. The connection can be made for example by means of a bolt and screw connection. Preferably neither the first housing part nor the second housing part and preferably also not the seal are destroyed and / or preferably neither the second housing part nor the third housing part and preferably also not the further seal are destroyed. The seal is preferably reusable after opening the housing, particularly preferably for sealing the space or the separation point between the first housing part and the second housing part when the first housing part and the second housing part are connected to one another again. Alternatively or in addition, this can apply to the additional seal, if any.

The first housing part may for example surround an opening, i. the housing part alone defines an opening. Alternatively, the housing part can define an opening together with further first housing parts. Anyway, the opening can be partially closed by means of the second housing. In other embodiments, the second housing part can define an opening in the first housing part, wherein the opening can be closed by means of the third housing part.

The opening which can be closed by means of the second housing part or the third housing part is preferably an access opening of the housing. An access opening is set up and intended to provide the user of the housing or the electrical operating device contained therein with access to the interior of the housing or to the operating device arranged in the housing. len. Through the access opening, the user of the housing can equip the interior of the housing with an operating device and / or carry out a modification, repair and / or action to operate the operating device. Access openings can be large enough for a user's hand to fit through the access opening. Receiving openings in housing parts for receiving electrical leadthroughs, in particular cable entries for electrical lines, or for receiving a fluid line for guiding a fluid into or out of the housing are not regarded as access openings for the purposes of this application. On receiving openings for receiving, for example, actuating attachments or detectors, in particular indicator lights, are not regarded as access openings in the sense of this application. Openings in parts of electrical feed-throughs, parts of line entries, parts of entries for fluid lines, parts of actuating attachments or (indicator) indicators are not regarded as access openings for the purposes of this application.

Preferably, the first housing part and the second housing part and / or optionally the third housing part is set up to separate the interior of the housing from the atmosphere surrounding the housing. Openings of the first housing part, the second housing part and / or the third housing part from the interior of the housing to the atmosphere around the housing are closed without ignition gaps when the housing is closed in an explosion-proof manner.

The first housing part and / or the second housing part is particularly preferably wall-shaped, trough-shaped, frame-shaped or box-shaped, or preferably at least wall-section, trough-section or box-section-shaped and / or the first housing part and / or the second housing part forms a section of a frame which can be closed by means of wall parts. The first housing part can, for example, be a frame part or a trough-shaped or box-shaped part or a section thereof and the second housing part can be a wall part, for example a side wall part, a lid or a base or a section thereof.

To close the housing, the seal can be arranged on one of the first sealing surface and the second sealing surface and optionally attached positively, non-positively and / or cohesively, and then the first sealing surface and the second sealing surface for elastic deformation adjacent to one another or to one another be arranged. Alternatively, to close the housing, the further sealing body can be arranged on one of the further second sealing surface and the third sealing surface and, if necessary, attached positively, non-positively and / or cohesively, and then the further second sealing surface and the third sealing surface for elastic deformation of the further Sealing body be arranged adjacent to one another or on one another.

The sealing body and / or the further sealing body can for example be closed in an annular manner. The sealing body and / or the further sealing body accordingly preferably surrounds the opening in the housing. The sealing body and / or the further sealing body can consist of elastomer or have elastomer or other elastic materials. For example, the sealing body and / or the wide re sealing body made of metal, in particular sheet metal, be formed. The sealing body can be closed-cell Have material or open-pore, but all passages through the pores are blocked by the sealing body. The sealing body and / or the further sealing body can have a tangled fiber body, for example made of metal fibers, the pores of which are at least partially closed by means of an elastomer, so that passages through the sealing body are avoided.

Large diameter openings in the housing can also be closed as provided according to the invention. The ratio of the length of the space filled by the elastically deformed seal (it can also be referred to as a separation point) between the first sealing surface and the second sealing surface to the width of the space between the first sealing surface and the second sealing surface with there between the Flameproof sealing device elastically deformed sealing body can, for example, be greater than 100. In embodiments, the ratio of the length of the space filled by means of the elastically deformed sealing body (it can also be referred to as a separation point) between the further second sealing surface and the third sealing surface to the width of the space between the further second sealing surface and the third sealing surface with an elastically deformed wide ren sealing body arranged in between for an ignition-proof seal, it can be greater than 100, for example. Manufacturing tolerances for the manufacture of the first and the second housing part and / or the second and the third housing part, in particular for the manufacture of the first sealing surface and the second sealing surface and / or the other second sealing surface and the third sealing surface, can be less strict than these are for the production of parts with surfaces that are flameproof Should define the flat gap between the surfaces.

With the sealing body according to the invention, small damage or unevenness of the sealing surfaces can be compensated for. In contrast to this, the surfaces of housing parts in the prior art, which adjoin one another in order to form a flat gap between the surfaces, must meet strict requirements in terms of integrity and flatness in order to exclude the passage of an ignitable gas mixture through the flat gap. The concept according to the invention is therefore particularly advantageous when the housing can be reclosed. This is because, in the open state, damage to the sealing surfaces or the surfaces which in the prior art limit the flameproof flat gap can certainly occur.

The sealing body can compensate for some damage due to its elasticity and close the separation point in spite of damage in a flameproof manner, while a housing known from the prior art with a flat gap with damage at the appropriate point can be unusable and must be replaced.

A spacer is preferably arranged which defines a minimum distance between the first sealing surface and the second sealing surface. This prevents the seal between the first sealing surface and the second sealing surface from being compressed to such an extent that the seal is so severely damaged, for example by plastic deformation, that it becomes unusable for the flameproof sealing or that the seal is at least when the Housing is not reusable. Is preferred when a connection is established between the first housing part and the second housing part, the first housing part and / or the second housing part pressed against the spacer so that the minimum distance as the distance between the first sealing surface and the second sealing surface in the space which is filled by the seal is set as the distance is.

To protect the seal, the first

Sealing surface and / or the second sealing surface preferably have an elongated structure. The structure can be a groove for example. The seal can be arranged next to or in the structure. Alternatively, the seal can be a flat seal which, in particular, is not arranged in a groove.

[0032] The elastically deformed sealing body preferably contacts the first sealing surface and the second sealing surface. Alternatively, between the elastically deformed sealing body and the first sealing surface and / or between the elastically deformed sealing body and the second sealing surface, a second sealing body, for example, can be arranged elastically deformed so that the sealing bodies form a stack between the first sealing surface and the second sealing surface.

The at least one device for explosion pressure reduction preferably assigned to the housing is set up and determines the maximum overpressure that can arise inside the housing due to an explosion to a maximum value which is smaller than the maximum value which is would occur in the same housing without the at least one device. The at least one device for explosion pressure reduction can aufwei sen a pressure relief body, which is arranged in or on an opening of the housing to the surrounding area of the housing in order to discharge gas from the interior of the housing for relief in the event of an explosion. Such a pressure relief body is designed to be flameproof in accordance with the protection class flameproof enclosure (Ex d, EN 6079-1 (standard)).

Alternatively or additionally, the at least one device for explosion pressure reduction can have a device which cannot let gas escape from the housing, but which can absorb heat and / or kinetic energy from the explosion in order to achieve the maximum overpressure to limit the explosion.

The device for reducing explosion pressure preferably has open-pore material. Due to its large surface, open-pore material can effectively cool the gas in order to reduce the maximum explosion pressure. Open-pored material can for example be fiber material, e.g. metal fiber material, e.g. be processed into a fabric, a scrim or a felt fibers, or be formed from a bed of pourable Ma material.

The at least one device for reducing explosion pressure is preferably set up and intended to generate an explosion overpressure (overpressure above atmospheric pressure) of a few bar, in particular greater than or equal to 10 bar, which would otherwise occur if the at least one device was in the otherwise unchanged housing would not be arranged to reduce to an overpressure of, for example, less than or equal to 1 bar. The inventors have recognized that, if such a device is provided to reduce explosion pressure, the possibility of arranging an elastic sealing body, which closes the separation point between two housing parts in a flameproof manner, even with housings with an internal volume of 1 liter or more or even 1000 liters or is more open, where in the prior art, for example, a flameproof flat gap delimited by two housing parts was to be provided or was provided. The first sealing surface and the second sealing surface, together with the elastically deformed sealing body arranged in between, can consequently replace a flameproof gap, which in the prior art is delimited by the first sealing surface on the one hand and the second sealing surface on the other. In embodiments of the invention, the one flat gap, be bordered by the first sealing surface on the one hand and the second sealing surface on the other hand, by a zünddurchschlagsi cheren or narrower gap between the first sealing surface and the sealing body and a flameproof or narrower gap between the second sealing surface and the sealing body be replaced.

Further advantageous embodiments and features result from the following description, the subclaims and the figures:

[0039] It shows by way of example and schematically:

[0040] FIG. 1 - a perspective view of an exemplary embodiment of the protective housing according to the invention of the protection type flameproof enclosure;

[0041] FIG. 2 - a perspective view of a first housing part of the protective housing shown in FIG. 1; Figure 3 - a perspective view of a cover of the protective housing shown in Figure 1,

Figure 4 - a perspective view of a sealing ring, which can be arranged between the cover and the first housing part shown in Figure 1,

Figure 5 - a cross-sectional view through a sealing ring with an enlarged detail,

Figure 6 - a schematic side view of a view into the interior of an inventive

Protective housing,

FIG. 7 - a partial sectional view through the separation point between the cover and the first housing part of the housing according to FIG. 1,

Figure 8 - a partial sectional view through the separation point between a first housing part and a second housing part of a protective housing according to the invention,

Figure 9a - a sealing body of an embodiment of a further embodiment of the housing according to the invention,

Figure 9b - a cross section through the embodiment with the sealing body according to Figure 9a,

FIG. 10a - an embodiment of a housing according to the invention in accordance with yet another embodiment in a perspective view,

FIG. 10b - the housing according to 10a with the cover elements open,

Figure 10c - a view of a detail of a cross section through the housing according to Figure 10a and Figure 10d - an enlarged section of the view according to Figure 10c.

The protective housing 10 according to the invention (hereinafter also referred to as the housing for short) preferably satisfies the "flameproof enclosure" type of protection. Requirements for housings of this type of protection are, for example, in the standard EN 60079-1 (Ex-d) or in other corresponding ones, For housings according to this protection class it is specified that the housing must withstand the pressure of an explosion of an explosive mixture inside the housing and prevent the explosion from being transmitted to the explosive atmosphere surrounding the housing.

In embodiments, the housing 10 according to the invention, as shown by way of example in FIG. 1, has a trough-shaped or box-shaped first housing part with a bottom (covered in FIG. 1), which first housing part 11 with a cover 12, which part of a second housing forms, is closed. The housing parts 11, 12 are preferably metal parts, for example made of aluminum, in particular aluminum alloy, steel or gray cast iron. The first sealing surface 13 and second sealing surface 14, which the first housing part 11 and the second housing part 12 aufwei sen, are preferably made of metal, for example aluminum, in particular aluminum alloy, steel or cast iron.

The first housing part 11 and / or the cover 12 can have receiving openings for feedthroughs such as pipeline feedthroughs and electrical feedthroughs 15 or receiving openings for receiving actuating elements 16 or displays or signaling devices 16. In the presented As an exemplary embodiment, an electrical bushing 15 for supplying an operating device with electrical power, an actuating device 16 and a display unit 17 is arranged in an opening of the first housing part.

The first housing part 11 also has a receiving opening in a side wall 18, which is closed by means of a pressure relief device 19. The pressure relief device 19 has a pressure relief body 20, which allows gas exchange between the interior of the housing 10 and the external environment 21 through the receiving opening and the pressure relief device 19. According to the protection type flameproof enclosure, however, gaps through the pressure relief body 20 are designed (in particular so long and so narrow) that gas or particles that escape through the pressure relief body 20 in the event of an explosion cool down to such an extent that they create an ignitable atmosphere outside of the housing 10 can not ignite ent. The gaps are therefore designated as flameproof.

The pressure relief device 19 can be screwed into the receiving opening in the side wall 18 of the first housing part 11, whereby it is ensured that the gap - a threaded gap - between the first housing part 11 and the pressure relief device 19 is ignition-proof. The other bushings and accessories such as actuators and signal transmitters, together with the receiving openings in the housing in which they are arranged, define flameproof gaps.

The first housing part 11 has an access opening opening 22 to a chamber 23 in the housing 10 (see FIG. 2). The access opening 22 is surrounded by a flange 24. The access opening 22 to the chamber 23 in the first housing part 11 is closed by means of the cover 12. To close the cover 12 is screwed to the first housing part 11 in the illustrated embodiment, for example. Other connection options are fundamentally possible, for example a latching connection. The chamber 23 contains at least one electrical operating device 25 which can generate sparks. Housings 10 according to the invention preferably limit internal volumes of at least 1 cubic decimeter, particularly preferably at least 4 cubic decimeters. Embodiments can in particular have an internal volume of at least 10 cubic decimeters. According to the invention, housings with a housing volume of, for example, 2000 liters can also be created. A housing 10 according to the invention consequently preferably has a relatively large internal volume, which can contain a correspondingly large amount of an ignitable gas mixture. The circumference (the closed length) of the separation point 26 between the first housing part 11 and the cover 12 can also be correspondingly large.

The sealing surface 13 of the first housing part 11 (first sealing surface) is arranged within an arrangement of devices for screwing, for example bores 27 for receiving bolts with external threads. FIG. 2 shows the exemplary housing 10 according to the invention according to FIG. 1 with the first housing part 11 open.

The cover 12, shown in Figure 3 with a view of the inside, has an arrangement of counter-devices for screwing the cover and the first housing part, for example holes 28 for receiving the thread bolt on. Within the arrangement, a groove can be arranged in the surface facing the flange 24 when the housing 10 is closed. A groove 30 can, however, also be dispensed with, so that the second housing part 12 has a stepless surface in the area of the sealing surface 14 of the cover 12 (second sealing surface). As an alternative or in addition to a groove 30 in the cover 12, a groove closed along the circumference can be worked into the surface of the flange 24 of the first housing part 11. The circumferential shape of the illustrated groove is rectangular, corresponding to the shape of the access opening 22. However, the circumferential shape can also be designed differently, in particular according to the shape of a differently shaped housing 10 and / or access opening 22. The groove 30 has a groove bottom 31, which forms a second sealing surface 14.

In Figure 4, a rectangular, closed in the circumferential direction, prefabricated sealing ring 32 is shown as a sealing body in the relaxed state. The seal 32 is closed circumferentially as a ring. That is to say, it has no gap or cut which would sever the sealing ring 32 transversely to the circumferential direction. The Darge presented relaxed seal 32 is quite angular in cross section. However, the seal 32 may also be of such polygonal cross-section, e.g. square, or for example circular, oval or elliptical. The sealing ring 32 can for example consist of polymer. Also a metal sealing ring 32, e.g. Sheet metal is possible. Of the

Sealing ring 32 can be glued to the cover 12, in particular to the second sealing surface 14 of the cover 12 - this is not shown in FIG. For example, the sealing ring 32 can be glued into the groove 30, in particular onto the groove bottom 31. The seal 32 can be foamed as a stamped seal or injection molded as an endless cord ring. As an alternative to a prefabricated sealing ring 32, the seal can be injected, foamed, extruded onto the surface to be sealed using a suitable additive manufacturing process (two components which together form an elastomer). The sealing ring 32 can for example be seamlessly closed or glued at the ends. Exemplary alternative embodiments of the sealing ring 32 are described in connection with FIG. The seal 32 can be pre-compressed and / or impregnated in order to provide the seal 32 with specific properties such as elasticity modulus or restoring force, water repellency, fire behavior and UV and aging protection.

The surface 29 of the cover 12 adjoining the groove 30 or the groove walls form a spacer 33 which ensures a minimum distance between the first sealing surface 13 and the second sealing surface 14 when the cover 12 is attached to the first housing part 11, with interposed and elastically compressed seal 32. If, with the housing 10 closed, the surface 29 of the cover 12 around the groove 30 and the second sealing surface 14 or the surface sections around the second sealing surface 14 are in contact, it is ensured that the Minimum distance as from stood between the first sealing surface 13 and the second sealing surface 14 is set. The seal 32 is thus pressed together by a predetermined amount or to a predetermined amount. This prevents damage or excessive deformations other than elastic deformations of the seal 32 and, on the other hand, ensures that the elastic seal 32 is sufficiently deformed, i.e. a sufficiently strong spring force on the cover 12 and first housing part 11 or second sealing element. surface 14 and first sealing surface 13 exercises to keep the separation point between the cover 12 and the first housing part 11 flameproof ge closed even in the event of an explosion. The spacer 33 can also be formed, other than by a groove 30, by a structure of projections arranged in a row or a projection closed in the circumferential direction (not shown), which applies next to the first sealing surface 13 and / or the second sealing surface 14. Alternatively, one or more spacers can be incorporated into the sealing ring (not shown), which prevent compression of the sealing ring 32 below a certain level.

FIG. 5 shows a cross-sectional view through an exemplary embodiment of a relaxed, elastically deformable sealing ring according to the imaginary section line S1 as shown in FIG. The seal 32 can in particular comprise closed-cell material. As can be seen by way of example from the enlarged detail, which is also shown in FIG. 5, the sealing ring 32 can be or have a tangled fiber body. The tangled fiber body per se has open pores 34. That is, without the additional measure described below, gas could pass from one side of the tangled fiber body 32 through the tangled fiber body through the open pores 34 which are formed between the irregularly arranged fibers 35 and leave the tangled fiber body again. Thus, the tangled fiber body 32 would not be free of passage gaps. However, this is prevented by the measure that the pores 34 are at least partially filled with elastomer 36 in order to close the paths (gaps) through the pores 34 and to obtain closed pores 34 in this sense. The pores 34 are already closed in the relaxed state of the sealing ring 32 or at least in the elastically deformed between the first sealing surface 13 and the second sealing surface 14 to stand. A seal 32 designed in this way has a high mechanical strength. This is particularly advantageous when the housing 10 can be re-closed by reusing the device 32.

Alternatively or in addition to the pressure relief device 19, which allows a gas exchange between the inner volume of the housing 10 and the outer atmosphere, the housing 10 can be assigned at least one pressure relief device 37 for internal pressure reduction, which increases the explosion pressure to a certain maximum Malwert limited, which is below the pressure wel cher would occur in an explosion if the pressure relief device 37 for internal pressure reduction were not present with otherwise unchanged housing. The pressure relief device 37 for internal pressure reduction can, for example, have at least one flat part 37 made of open-pore material, which is for example attached to the cover, e.g. glued to this. In the embodiment of the lid shown in Figure 3, for example, two flat parts 37 are glued to the inside as an inner pressure relief device 37 made of open-pored material.

The device 37 for internal pressure relief is not like the pressure relief device 19 for closing the opening in the side wall 18 of the first housing part 11 for the connection between the interior of the housing 10 and the exterior of the housing 10 against ignition penetration, but for that Allow non-ignitable exit gen gas set up. Rather, devices 37 for internal pressure relief are set up and intended to absorb thermal energy when an explosion occurs in order to cool the explosion gas and thereby reduce pressure peaks. The effect of the pressure relief device 37 for internal pressure reduction can additionally or alternatively be based on other physical principles in that these, for example the flat part 38 made of open-pored material, is deformed by the explosion pressure surge and thereby absorbs movement energy and thus leads to a reduction in pressure peaks. Be that as it may, the pressure relief device 37 for internal pressure reduction provides no connection between the interior of the housing 10 and the surroundings of the housing 10 to release gas from the hous se 10, but the device 37 for internal pressure reduction takes one Part of the explosion energy to dampen the effect of the explosion, but without having to release gas from the interior of the housing 10 to the outside. Columns which lead through the porous material of the device to the internal pressure reduction 37 are preferably not flameproof. In other words, the open-pored material of the device for internal pressure reduction 37 is not flameproof.

FIG. 6 shows, in a highly schematic manner, a side view into the interior of a protective housing 10 according to an exemplary embodiment. An operating device 25 which can generate sparks is shown very schematically. In addition or as an alternative to the device 37 for internal pressure reduction as shown in Figure 3 and / or the pressure relief device 19, which provides a gap-free connection between the interior of the housing 10 and the surroundings of the housing 10, in the interior Space 23 of the housing 10 further or other devices for internal pressure reduction can be arranged. For example, a body 39, which has open-pore material, can be arranged in the chamber 23, which body is accessible from at least four or at least five sides of the body 39. Alternatively or additionally, one or more walls can be provided with open-pored flat material 40. The devices 37, 39, 40 for internal Druckredu decoration are used by cooling the explosion gases and / or absorption of kinetic energy and the Druckentlastungsvor device 19 for exchanging gas between the interior 23 and the environment of the housing 10 ultimately serve to prevent pressure peaks, so that the elastically formed seal 32 can withstand the explosion overpressure that actually occurs and thus a flameproof seal between the first sealing surface 13 and second sealing surface 14 is ensured in the event of an explosion inside the housing 10. The open-pored material of the body 39 and the flat material 40 does not have to be flame-proof.

The one or more devices 19, 37, 39, 40 for pressure reduction can in particular provide long (measured closed along the circumference) seals 32 or long (measured closed along the circumference) separation points between housing parts 11, 12 be sealed in a flameproof manner. In FIG. 7, a partial sectional view is shown in accordance with

Section line S2 as shown in FIG. The separation point 26 between the first sealing surface 13 and the second sealing surface 14 has a width W which corresponds to the height H of the sealing body 32 deformed elastically between them. The width W is perpendicular to the direction (indicated by the arrow P) or the path that the gas would take in the event of an explosion in the absence of a seal 32 through the separation point 26 between the first sealing surface 13 and the second sealing surface 14. The width is preferably measured transversely or perpendicular to the first sealing surface 13 and / or to the second sealing surface 14 and corresponds to the distance between the first sealing surface 13 and the second sealing surface 14. The width W is perpendicular to the circumferential direction or to the length of the separation point 26 or the seal 32 measured. The length of the separation point or the sealing body corresponds to the circumference or circumferentially closed measured length of the sealing ring 32 or the length of a line which connects imaginary centers of the cross sections of the sealing body 32 miteinan. In the exemplary embodiment shown in FIGS. 1, 2 and 3, the length of the separation point is the sum of the lengths of the four straight sections of the groove 30.

The ratio of the length to the width W of the separation point or length to the height of the seal can be 100 or greater, for example. In this sense, the seal 32 according to the invention or the separation point 26 between the first sealing surface and the second sealing surface is preferably a long seal 32 or a long separation point 26.

In Figure 8 is an exemplary sectional view through mutually facing surfaces of the first housing part 11 and the second housing part 12 with the housing 10 closed according to a further embodiment is shown. Corresponding to the shape of a tongue-and-groove connection, a sealing ring 32 is received in grooves 30a, 30b arranged opposite one another, which are arranged in the surface of the first housing part 11 and the facing surface of the second housing part 12. To close the housing 10 (for the first time), the following procedure can be used, for example, starting with the first housing part 11, as shown in FIG. 2:

The sealing ring 32 (e.g. according to FIG. 4) can, for example, be placed on the second sealing surface 14 to close the housing 10, in particular placed in the groove 30. Alternatively, the sealing ring 32, in particular special in the absence of a groove 30 in the cover 12, can be placed on the first sealing surface 13. The sealing ring 32 can be glued to the first sealing surface 13 or the second sealing surface 14 ver. Alternatively, the seal 32 can, for example, be applied in pasty and / or liquid form to the first sealing surface 13 or the second sealing surface 14, where the sealing material is converted into a (rubber) elastic state by a chemical and / or physical process .

The cover 12 (for example according to FIG. 3) is arranged on the first housing part 11, so that the seal 32 is arranged between the first sealing surface 13 and the second sealing surface 14. The cover 12 is attached to the first housing part 11 by means of a form-fitting and / or force-fitting connection. By means of the screw connection, as it is provided according to the embodiment shown in Figures 1 and 2, the connection in the direction of the elastic deformation of the device 32, which is generated when making the connection, is form-fitting. Alternatively or additionally, the connection can be force-fit in the direction of the elastic deformation. In any case, the restoring force due to the elastically deformed sealing Compensated device, which tries to urge the cover 12 and the first housing part 11 away from each other in order to maintain the elastic deformation. After establishing the connection with an elastic deformation to or below a predetermined level, the housing shown in FIG. 2 is closed in an explosion-proof manner.

Nevertheless, an explosive mixture can collect in the housing 10. In particular, gas can penetrate from the outside into the chamber 23 bounded by the housing and form an explosive mixture there if the housing 10 is not gas-tight, for example if the housing has a pressure relief device 19 which connects between the interior 23 of the housing 10 and the environment 21 creates, as in the embodiment according to Fi gures 1 and 2. The electrical operating means 25, which is arranged in the interior 23 of the housing 10, can generate a spark. This is also permitted within the scope of the protection type flameproof enclosure. The explosion thus ignited leads to an overpressure inside the housing 10. The one or more pressure relief devices 19, 37, 39, 40 are designed so that this overpressure is limited to a specific maximum value (is equal to or less than the specific one Maximum value), which is well below the maximum value that would occur if one or more of the pressure relief devices 18, 37, 39, 40 were not present. However, this predetermined maximum overpressure is selected to be so small that the seal 32 keeps the separating point 26 between the first sealing surface 13 and the second sealing surface 14 closed in a flameproof manner even during the occurrence of an explosion. The overpressure (difference between pressure and atmospheric pressure) due to the explosion can without the one or more pressure relief devices 19, 37, 39, 40, for example, be greater than or equal to 10 bar.

With the one or more pressure relief devices 19, 37, 39, 40, the maximum overpressure can, for example, be less than or equal to 1 bar.

Repeated explosions can also occur. At least during the explosions, the seal 32 keeps the separation point 26 between the first sealing surface 13 and the second sealing surface 14 closed in a flame-proof manner, preferably also between explosions. So it is preferably not the explosion pressure, which finally presses the seal 32 against the first sealing surface 13 and the second sealing surface 14, but rather the elastic deformation due to the connection established between the first housing part 11 and the second housing part 12 closes the separation point 26 from flameproof.

The housing 10 can preferably be opened non-destructively. In particular, the housing parts 11, 12 do not have to be damaged or destroyed. The sealing ring 32 also preferably remains undamaged. After opening, the sealing ring 32 can preferably be used again to close the housing 10 in such a way that it is protected against ignition. However, regardless of whether a new sealing ring 32 has to be used or the old sealing ring 32 can be reused, the housing 10 is preferably resealable.

In known housings of the "flameproof enclosure" type of protection, when the housing is closed, a flat gap is provided in the separation point between the cover and the housing part, which surrounds the interior, which that's for sure. In the event of an explosion, gas can consequently pass through the separation point between the cover and the housing part. In the prior art, sealing rings arranged in the separation point cannot prevent this. These serve only to exclude moisture from the housing. In housings known from the prior art with a sealing ring and flat gap, the sealing ring cannot seal the separation point between the cover and the housing part in a flameproof manner, especially when an explosion occurs. It is imperative that the surfaces on the cover and housing part be designed in such a way that they define a gap to prevent flameproofing. This requires maintaining close tolerances in the manufacture of the cover and the housing.

In the housing 10 according to the invention, the

Housing parts 11, 12, in particular the first sealing surface 13 and the second sealing surface 14, must be manufactured according to greater tolerances than would have to be adhered to in order to provide a flat gap that is safe from flameproofing at this point 26. This makes the manufacture of a housing 10 according to the invention easier.

Due to the simpler requirements on the first sealing surface 13 and the second sealing surface 14 or on the first housing part 11 and the second housing part 12, housing 10 can be created which not only has an access opening 22 (like the housing 10 according to FIG 1), but several access openings (at least two) through which access to the operating means 25 is possible, but which, when the housing 10 is closed, according to the invention is closed with seals 32 in a flame-proof manner. In a modification of the housing 10 as in Figure 1, for example, the bottom can not be integrally connected to the rest of the trough-shaped or box-shaped first housing part, but a separate second housing part can form the bottom, which menteil accordingly the flange connection between cover 12 and first housing part 11 via a flange connection with a frame connected is. The frame part surrounds an interior of the housing and has two opposite access openings, one of which is closed with the cover and the other with the base via elastically deformed seals according to the invention between first and second sealing surfaces in a flameproof manner. In embodiments of the housing with one or more access openings, each access opening is preferably sealed in a flame-proof manner by means of a corresponding seal, even in the event of an explosion.

To explain the embodiment according to the figures

9a and 9b, the explanations given for the other embodiments can be used unless otherwise described below.

FIG. 9a shows an example of an annular or frame-shaped sealing body 32 of the embodiment in a non-elastically deformed state. The sealing body 32 can have an inner section 32a, which actually effects the flameproof closure, and an outer section 32b surrounding it, which can be connected to the inner section 32a, eg glued or welded. In exemplary embodiments, the inner section 32a and the outer section 32b can be seamlessly connected to one another in one piece. In other exemplary embodiments, the section 32a and 32b can be separate Be parts.

The seal body 32 defines an opening area F. A normal vector of the opening area F points in the normal direction R. The inner section 32a can be more flexible, parallel to the normal direction R of the opening area F, which is perpendicular to the opening area, than the outer section 32b. The dimension (thickness) of the inner section 32a, measured in the normal direction R, can be greater than the dimension of the outer section 32b, at least in the non-elastically deformed state parallel to the normal direction R of the opening surface F.

The inner portion 32a and / or the outer portion 32b are preferably made of metal. The inner section 32a and / or the outer section 32b can form sheet metal strips for example. The inner section 32a can, for example, essentially be manufactured from a sheet metal part into which the opening is cut. Alternatively or additionally, the outer section 32b can be made from a sheet metal part into which an opening is cut, in which the inner section 32a is arranged. In the outer portion 32b bores are provided through which screws can lead in order to connect the second housing part 12 and the first housing part 11 to one another.

FIG. 9b shows, in a cross-sectional view, the inner section 32a of the sealing body 32, elastically deformed parallel to the normal direction of the opening surface F between the first housing part 11, a housing body with a flange 24 with a first sealing surface 13, and a second housing part 12 , a cover with a second sealing surface 14. The outer section 32b forms an ab- spacer or limited, up to which dimension the inner section 32a can be compressed parallel to the normal direction R of the opening area F, the inner section 32a. This avoids damage to the inner section 32a, but at the same time gives the fitter a clue as to when the inner section 32a is sufficiently compressed to produce security against ignition.

In the arrangement according to Figure 9b, the space in the separation point between the first sealing surface 13 of the flange 24 of the housing body 11 and the sealing body 32 due to the dimensions of the inner portion 32a is so narrow and so long that explosion gases from the interior 23 of the Ge housing 10 can at most leave cooled in such a way that an ignition of the atmosphere outside the housing 10 cannot take place. The same applies to the space in the separating point between the second sealing surface 14 of the cover 12 and the sealing body 32. The sealing body 32 itself is free of passage gaps. Even in the event of an explosion, gas cannot escape from the interior 23 of the housing through the sealing body 32 through the space between the first sealing surface 13 and the second sealing surface 14, because there is no gas connection between the interior 23 through the cross section of the sealing body 32 of the housing 10 and the external environment 21 of the housing 10.

The inventive concept can also be used for housing 10 with large access openings. The ratio of the length of the space 26 filled by the sealing body 32 between the first sealing surface 13 and the second sealing surface 14 to the width W of the space 26 between the first sealing surface and the second sealing surface is both for example at least 100. The width W is measured in the direction of elastic compression of the sealing body 32 or parallel to the normal direction R.

In the figures 10a to 10d an example of yet another embodiment of the housing 10 according to the invention is shown, for which the explanations of the other embodiments can be used, unless otherwise described below.

The housing 10 has a frame-shaped housing body 11 (first housing part) and two cover elements 41a, 41b (further second housing parts) which can close one side of the housing body 11. A flat part, which forms an intermediate frame 42, is arranged between the cover elements 41a, 41b and the housing body 11. The intermediate frame forms a second housing part 12. The cover elements 41a, 41b can be hinged to the intermediate frame. The intermediate frame 42 has a web 43, for example in the middle, which divides the access opening 22 in the housing body into two partial openings.

As can be seen in particular from FIG. 10d, a frame-shaped sealing body 32 is arranged between the first sealing surface 13 of the flange section 24 of the housing body 11 and the second sealing surface 14 of the intermediate frame 42. Between a further second sealing surface 45 of the intermediate frame 42 and the sealing surface 46 (third

Sealing surface) of the cover element 41a, a frame-shaped flat part is arranged as a further sealing body 47. Between tween the other cover element 41b and the flange section 24, the arrangement is corresponding. The further sealing body 47 can be in the closed state between tween two cover elements 41a, 41b on the one hand and the On the other hand, intermediate frames 42 extend (see FIG. 10b, which shows the further frame-shaped sealing body 47 with a web section 47a) or there is a separate further sealing body for each partial opening. The sealing body 32 and the further sealing body 47 are preferably more flexible than the intermediate frame 42 in the direction parallel to the normal direction R of the opening surface. The further sealing body 47 can have one or more of the features described here in connection with the sealing body 32.

In the arrangement according to FIG. 10d, the space in the separation point between the first sealing surface 13 of the flange 24 of the housing body 11 and the sealing body 32 is so narrow and so long that explosive gases from the interior 23 can leave the housing 10 at most cooled to such an extent that so that an ignition of the atmosphere outside the housing 10 cannot take place. The same applies to the space in the separation point between the second sealing surface 14 of the inter mediate frame 42 and the sealing body 32 and for the space in the separation point between the other second

Sealing surface of the intermediate frame 42 and the further sealing body 47 and also for the space in the separation point between the third sealing surface of the cover elements 41a,

41b and the further sealing body 47. However, even in the event of an explosion, gas cannot pass through the sealing body 32 through the space between the first sealing surface 13 and second sealing surface 14 and also not through the sealing body 47 through the space between others second sealing surface 45 and third sealing surface 46, because through the cross section of the sealing body 32 or through the cross section of the sealing body 47 is no gas connection between the Interior 23 of the housing 10 and the external environment 21 of the housing 10 made.

For the elastic deformation of the sealing body 32 between the intermediate frame 42 and first housing part 11 and the further sealing body 47 between the intermediate frame 42 and cover elements 41a, b, the cover elements 41a, 41b can be screwed to the flange 24 of the first housing part 11, for example.

In preferred embodiments of the housing 10 according to the invention, a flameproof seal of the separation point 26 between the first housing part 11 and the second housing part 12 is produced solely on the basis of the elastic deformation of the seal 32. In particular, pouring out a separation point between the first housing part and the second housing part after establishing the connection between the first housing part and the second housing part is not absolutely necessary in order to obtain a flameproof termination of the separation point, and is preferably not done either. The elastic deformation of the seal 32 is preferably obtained when the positive and / or non-positive connection, but preferably not a material connection, is established between the first housing part 11 and the second housing part 12. The first sealing surface 13 and the second sealing surface 14 are preferably oriented transversely, in particular perpendicular, to the force with which the first housing part 11 and the second housing part 12 are pressed together when the connection between the first housing part 11 and the second housing part 12 is established become. Between the first housing part 11 and the second housing part 12, a non-positive and / or positive connection is established, which the force that the elastically deformed seal 32 on the first Sealing surface 13 and the second sealing surface 14 exerts in order to push them away from one another, compensated and, moreover, withstands a force impulse in the event of an explosion in order to keep the housing 10 closed in a flame-proof manner.

According to the invention, a protective housing 10 is created in the explosion protection type, pressure-resistant encapsulation. At least one device 19, 36, 38, 39 for reducing explosion pressure is preferably assigned to the housing 10. The housing 10 has a first housing part 11 with a first sealing surface 13 and a second housing part 12 with a second sealing surface 14, wherein - in the pressure-tight closed state of the housing 10 - an elastic device 32 is elastically deformed between the first sealing surface 13 and the second sealing surface 14 is held and thereby closes the space 26 between the first sealing surface 13 and the second sealing surface 14 in the event of an explosion in the interior of the housing 10 in a flame-proof manner. The flameproof arrangement according to the invention can replace a flat gap between, for example, a surface of a cover and a surface of a housing part, which gap requires compliance with relatively narrow manufacturing tolerances.

Reference character list:

Claims

Patent claims:

1. Protective housing (10) in the explosion protection type pressure-tight encapsulation, the housing (10) preferably we at least one device (19, 36, 38, 39) for reducing explosion pressure is assigned, the housing (10) having a first housing part (11) with a first sealing surface (13) and a second housing part

(12) with a second sealing surface (14), where in - in the pressure-tight closed state of the housing

(10) - an elastic sealing body (32, 47) is held elastically deformed between the first sealing surface (13) and the second sealing surface (14) and thereby the space (26) between the first sealing surface

(13) and the second sealing surface (14) closes in a flameproof manner in the event of an explosion in the interior of the housing (10), the elastically deformed sealing body (32, 47) being free of passage gaps.

2. Housing (10) according to one of the preceding claims, wherein the connection between the first housing part

(11) and the second housing part (12) is non-destructive detachable.

3. Housing (10) according to one of the preceding claims, wherein the first housing part (11) surrounds an access opening (22) or defines an access opening (22) which is closed by means of the second housing part (12).

4. Housing (10) according to claim 3, wherein the housing we have at least two access openings (22), wherein the separation point (26) between the first Ge housing part (11) and the second housing part (12) with means of a sealing body (32) which is elastically deformed between a first sealing surface (13) and a second sealing surface (14) in a flame-proof manner.

5. Housing (10) according to one of the preceding claims, wherein the first housing part (11) is tub, box or frame-shaped and wherein the second housing part (12) is a wall part, in particular a cover (12), a base or a side wall part is.

6. Housing (10) according to one of the preceding claims, wherein for closing the housing (10) of the sealing body (32) has been arranged on or on the first sealing surface (13) or the second sealing surface (14) and then the first sealing surface (13) and the second sealing surface (14) for the elastic deformation of the sealing body (32) are pressed towards each other.

7. Housing (10) according to one of the preceding claims, wherein the sealing body (32) has closed-pore Ma material.

8. Housing (10) according to one of the preceding claims, wherein the sealing body (32) has a tangled fiber body, the pores (34) of which are at least partially closed by means of an elastomer (35) so that passage paths for gas through the cross section of the sealing body (32 ) are avoided.

9. Housing (10) according to one of the preceding claims, wherein the ratio of the length of the means of the sealing processing body (32) filled space (26) between the first sealing surface (13) and the second sealing surface (14) to the width (W) of the space (26) between the first sealing surface (13) and the second sealing surface (14) larger 100 is.

10. Housing (10) according to one of the preceding Ansprü surface, wherein a spacer (33) between the first sealing surface (13) and the second sealing surface (14) is arranged, which has a minimum distance between the first sealing surface (13) and the second The sealing surface (14).

11. Housing (10) according to one of the preceding claims, wherein the first housing part (11) and / or the second housing part (12) has a, preferably elongate, structure (30), in particular a groove (30), wherein the sealing body (32) is contained in the structure (30), in particular groove (30), or is arranged to run alongside the structure (33), or wherein the sealing body (32) forms a flat seal.

12. Housing (10) according to one of the preceding claims, wherein the device (19, 36, 38, 39) for reducing explosion pressure has open-pored material.

13. Housing (10) according to one of the preceding claims, wherein the device (19) for explosion pressure reduction has a pressure relief body (20) which is arranged in an opening of the housing (10) to the environment of the housing (10).

14. Housing (10) according to one of the preceding claims, wherein the device (36, 38, 39) for explosion pressure reduction has open-pored material which is not flameproof.

15. Housing (10) according to one of the preceding claims, wherein the second housing part (12) has a further second sealing surface (45) and the housing (10) has a third housing part (41a, 41b) with a third sealing surface (46) wherein - in the pressure test closed state of the housing (10) - another elastic sealing body (47) is held elastically deformed between the further second sealing surface (45) and the third sealing surface (46) and thereby the space between the further second sealing surface ( 45) and the third sealing surface (46) closes in a flame-proof manner in the event of an explosion in the interior (23) of the housing (10).