Pressure Release Device

Abstract

The invention relates to a pressure relief device (1) for a housing (2) which is protected against explosions, in particular is compression-proof and has a wall connecting piece (3) which can be at least partially inserted into a housing opening (4) of a housing wall (6) by its insertion connecting piece section (5), which can be in particular detachably fixed from an inner side of the housing and rests from the outside on an opening edge (8) of the housing opening (4) in its inserted and fixed position with a radially outwardly projecting support flange (7), wherein the insertion connecting piece section (5) furthermore comprises a projecting connecting piece section (9) which is opposite the insertion connecting piece section relative to the support flange (7) and comprises a longitudinal conduit (10) running through the wall connecting piece (3) into which conduit a flame-blocking body (11) is replaceably inserted, wherein a pressure nut (13) which loads the flame blocking body (11) with pressure in its insertion position and with a pressure edge (14) projecting radially inward at least in sections can be screwed onto a free end section (12) of the projecting connecting piece section (9), and wherein the pressure edge (14) contacts an outer viewing side of the flame blocking body (11).

Claims

1. A pressure relief device for a housing comprising: a wall connecting piece including an insertion connecting piece configured to be at least partially inserted into a housing opening of a housing wall of the housing and configured to be detachably fixed to the housing, the wall connecting piece including a support flange projecting radially outward from the insertion connecting piece and configured to rest on the outside of an opening edge of the housing opening when the insertion connecting piece is inserted and fixed to the housing, the wall connecting piece including a projecting connecting piece section opposite the insertion connecting piece section relative to the support flange, the projecting connecting piece section defining at least a portion of a longitudinal conduit running through the wall connecting piece; a flame-blocking body replaceably inserted into the longitudinal conduit; and a pressure nut which secures the flame-blocking body in the longitudinal conduit in an insertion position, the pressure nut configured to be threadably connected to a free end section of the projecting connecting piece section, the pressure nut including a pressure edge projecting radially inward that loads the flame blocking body with pressure in the insertion position, the pressure edge configured to contact an outer viewing side of the flame blocking body.

2. The pressure relief device according to claim 1, wherein the longitudinal conduit includes a radially inwardly projecting support step for fixing the insertion position of the flame blocking body, wherein the pressure relief device further comprises a spacer ring arranged between the support step and the flame blocking body.

3. The pressure relief device according to claim 1, wherein the projecting connecting piece section includes an outer thread which fits an inner thread of the pressure nut.

4. The pressure relief device according to claim 1, wherein the pressure edge is disposed on an outer free end of the pressure nut, the pressure edge having an outer side that is shaped as a screw-in polygon, the pressure edge including a pressure projection on a lower side of the pressure edge that engages the flame blocking body.

5. The pressure relief device according to claim 1, further comprising a tight-fit screw that can be screwed laterally into the pressure nut to secure the pressure nut to the projecting connecting piece section.

6. The pressure relief device according to claim 1, wherein the flame blocking body is a sintered body and has a flat upper side and a lower side with a flat edge area between the flat upper side and lower side, the flat upper side defining the outer viewing side.

7. The pressure relief device according to claim 2, wherein the spacer ring is formed by a flame-protected or fire-proof material.

8. The pressure relief device according to claim 1, wherein the insertion connecting piece section has a thread relief groove on an end section of the insertion connecting piece section bordering the support flange.

9. The pressure relief device according to claim 1, wherein the flame blocking body is inserted without an ignition gap into the longitudinal conduit.

10. The pressure relief device according to claim 1, further comprising an intermediate connecting piece arranged between the pressure nut and substantially the support surface, the intermediate connecting piece including a connection piece end section configured to be threadably connected to the projecting connection piece section and a nut end section configured to be threadably connected to the pressure nut, wherein the intermediate connecting piece includes a pressure step which projects radially inward and loads the flame blocking body with pressure in the direction of the support step.

11. The pressure relief device according to claim 10, wherein the pressure step is arranged on a lower end of the nut end section.

12. The pressure relief device according to claim 11, wherein the nut end section includes a radially inwardly projecting annular step having an outside diameter that is substantially equal to an outside diameter of the support step.

13. The pressure relief device according to claim 12, wherein a sprayed water body is arranged on the annular step and loaded with pressure by the pressure edge of the pressure nut in the direction of the annular step, wherein the sprayed water body for protection against sprayed water is a sintered body.

14. The pressure relief device according to claim 13, wherein the sprayed water body for protection against sprayed water and the flame blocking body are produced from the same material.

15. The pressure relief device according to claim 14, wherein the sprayed water body for protection against sprayed water has a higher density than the flame blocking body.

16. The pressure relief device according to claim 15, wherein the sprayed water body for protection against sprayed water includes at least one drainage opening, wherein each drainage opening is a radially outwardly open edge groove.

17. The pressure relief device according to claim 16, wherein the annular step includes a bunghole connecting the longitudinal conduit and each drainage opening, wherein the sprayed water body for protection against sprayed water and the flame blocking body are arranged at a distance from one another in the longitudinal conduit.

18. The pressure relief device according to claim 17, further comprising a moisture protection membrane replaceably arranged between the sprayed water body for protection against sprayed water and the flame blocking body.

19. The pressure relief device according to claim 10, further comprising a tight-fit screw that can be screwed into the intermediate connecting piece to secure the intermediate connecting piece to the projecting connecting piece section, wherein the intermediate connecting piece includes a radially outwardly projecting screw-in polygon.

20. The pressure relief device according to claim 13, wherein the sprayed water body for protection against sprayed water and the flame blocking body are elastic under pressure and include a pore closure on the outer edge side.

Description

[0031] The invention is explained and described in detail in the following using the figures attached in the drawings.

[0032] In the figures:

[0033] FIG. 1 shows an exploded view of an exemplary embodiment of a pressure relief device;

[0034] FIG. 2 shows an enlarged view of the combined pressure relief devices according to FIG. 1;

[0035] FIG. 3 shows a view analogous to FIG. 2 for a second exemplary embodiment of a pressure relief device with an intermediate connection piece;

[0036] FIG. 4 shows a sectional view of the pressure release device according to FIG. 3, and

[0037] FIG. 5 shows an enlarged view in particular of a body for protection against sprayed water according to FIG. 4.

[0038] FIG. 1 shows an exploded view of a first exemplary embodiment of a pressure relief device 1 according to the invention. It is inserted into a housing opening 4 of the housing 2 which is not shown in more detail and comprises a wall connecting piece 3. The wall connecting piece 3 comprises an insertion connecting piece section 5 and a projecting connection piece section 9. The support flange 7 is arranged between these two. In the case in which the connecting piece section 5 is completely inserted in the housing opening 4, the support flange 7 rests along an opening edge 8 of the housing opening 4 from the outside on the corresponding housing wall 6. The insertion connecting piece 5 comprises an outer thread 50 onto which a corresponding counter nut can be screwed from the inside of the housing, or which can be screwed into an opening thread.

[0039] The corresponding pressure release device 1 serves to release the pressure if a certain explosion pressure builds up inside the housing. The corresponding housing 2 should be built to be explosion-proof and in particular pressure-proof. Upon an explosion in the housing the corresponding explosion pressure is relieved by the corresponding pressure relief device in that corresponding explosion gases exit to the outside via a flame blocking body of the pressure relief device. This flame blocking body is gas-permeable and secure against complete ignition. According to the invention the flame blocking body 11 is arranged inside a corresponding longitudinal conduit 10 of the pressure relief device 1, wherein this longitudinal conduit 10 extends through the wall connecting piece 3 as well as through a corresponding pressure nut 13.

[0040] The projecting connecting piece section 9 has a free end section 12 with outer thread 19 and has an end section 29 with thread 19 relief groove 30 between this outer thread 19 and the support flange 7.

[0041] The pressure nut 13 can be screwed onto the outer thread 19 by a corresponding inner thread 18.

[0042] The support flange 7 comprises a hexagon along its outer circumference in order to fix it by a tool in its position during the screwing on of the corresponding counter nut from the inside of the housing.

[0043] The insertion connecting piece section 5 has an undercut 49 above a corresponding outer thread 50, which undercut directly follows the support flange 7.

[0044] The flame blocking body 11 is preferably constructed as a sintered body 25. The latter can be produced from appropriate, inflammable materials such as ceramic foam, metallic fibers or the like. The flame blocking body has an appropriate porosity which makes possible the permeability of gas and at the same time ensures the complete ignition safety.

[0045] The flame blocking body 11 has an upper side 26 and a lower side 27 which are connected by an edge area 28. In the exemplary embodiment shown, the upper side 26 and the lower side 27 are designed to be flat, wherein, however, a curvature can be present in the entire range of the upper side or of the lower side or at least along the edge of the upper side and the lower side. Such a curvature can be either concave or convex. If the pressure nut 13 is screwed onto the projecting connecting piece section 9, it can be secured in its screwed-on position by, for example, a tight-fit screw 24. The screw is laterally screwed into the pressure nut into a corresponding thread bore 28, see also FIG. 2. Instead of only one flame blocking body 11, two or more flame blocking bodies can be arranged as well as, for example, also a spacer ring 17 in addition. The latter also consists of a fireproof material or at least of a fire-protected material which can be an appropriate plastic, a sintered material or the like.

[0046] FIG. 2 shows the corresponding parts according to FIG. 1 in their assembled position. It can be recognized in the longitudinal section that the projecting connecting piece section 9 comprises a radially inwardly projecting support step 16 on its inner side. The flame blocking body 11 can be directly arranged on this step or optionally between it and the support step of the corresponding spacer ring 17. The flame blocking body 11 is clamped in between support step 16 or spacer ring 17 and pressure nut 13. The pressure nut 13 comprises a radially inwardly projecting pressure edge 14. This edge comprises on its inner, free end 20 a pressure projection 23 which projects downward from its lower side. This projection rests from above on a corresponding outer viewing surface 15 of the flame blocking body 11 and loads it with pressure in the direction of the support step 16 and the spacer ring 17. In FIG. 2 the pressure nut 13 is screwed by its inner thread 18 to the corresponding outer thread 19 of the projecting connecting piece section 9.

[0047] In this manner the flame blocking body 11 is loaded in such a manner that it is arranged in the longitudinal conduit 10 without an ignition gap and in a gas-permeable manner.

[0048] The pressure nut 13 comprises on the outer edge of the corresponding pressure edge 14 a corresponding screw-in square 21, in particular in the shape of a hexagon.

[0049] The edge area 28 has a close contact with an inner side of the longitudinal conduit 10 so that no ignition gap or other free spaces are formed between the latter.

[0050] FIG. 3 shows a second exemplary embodiment of a pressure relief device 1 analogous to FIG. 2. This pressure release device 1 differs from the pressure release device already described especially by an intermediate connecting piece 1. The latter serves as an intermediate component between wall connecting piece 3 and pressure nut 13. In analogy with FIG. 2, the corresponding flame blocking body 11 is placed in this case without additional support ring 17 on the support step 16. The corresponding pressure loading of the flame blocking body 11 in the direction of the support step 16 takes place by a radially inwardly projecting pressure step 34. The latter is formed on the lower end 35 of a nut end section 33 of the intermediate connecting piece 31. The intermediate connecting piece 31 furthermore comprises a connecting piece end section 32 which is screwed onto the corresponding outer thread 19 of the projecting connecting piece section 9 in analogy with the pressure nut 13 according to FIG. 2. A corresponding outer hexagon is formed between connecting piece and section 32 and nut end section 33. Furthermore, a radially inwardly projecting annular step 36 is formed in the area of the nut end section 33. The latter comprises approximately the same outside diameter 37, see FIG. 4, as the support step 16 with its outside diameter 38.

[0051] The annular step 36 serves to arrange a body for protection against sprayed water 39. The latter can be produced from the same material as the flame blocking body. As a rule, the body for protection against sprayed water 39 is also a sintered body 40. A density of the body for protection against sprayed water 39 is less than a corresponding density of flame blocking body 11. As a consequence, for example, given the same material for both bodies the corresponding porosities differ in the case of a back body. That is, the body for protection against sprayed water has a lower porosity.

[0052] The body for protection against sprayed water 39 is held analogously to FIG. 2 by the corresponding pressure nut 13 and is loaded with pressure in the direction of annular step 36.

[0053] Furthermore, the intermediate connecting piece 31 can be secured in its screwed-on position 45 for example by a tight-fit screw 46, see FIG. 3, analogously to the pressure nut 13.

[0054] Drainage openings 41 are visible on a top side 51 of the body for protection against sprayed water 39 in the area of the pressure edge 14 of the pressure nut 13. These openings extend outward, see also FIG. 4, in particular in the shape of radially outwardly open edge grooves 42 between the inner chamber limited by the body for protection against sprayed water 39 and the flame blocking body 11. The drainage openings 41 serve as dehumidifying openings for any moisture present in the corresponding inner chamber. Furthermore, the body for protection against sprayed water 39 serves a protection against sprayed water and dust or other contaminating particles. The body for protection against sprayed water 39 prevents a penetration of the latter into the longitudinal conduit 10.

[0055] An upper part of the pressure relief device 1 according to FIG. 3 is visible in FIG. 4 in another longitudinal section. In addition, in FIG. 4 a moisture protection membrane 44 is arranged in the intermediate space between the body for protection against sprayed water 39 and the flame blocking body 11 as an alternative for another exemplary embodiment. The moisture protection membrane 44 can also be directly arranged, for example, on a lower side of the body for protection against sprayed water 39 and/or on a top side of the flame blocking body 11. The moisture protection membrane 44 protects against a penetration of moisture in the direction of the flame blocking body. The tear resistance of the moisture protection membrane 44 is designed in such a manner that it already tears at a relatively low pressure at which a corresponding pressure reduction takes place by the pressure relief device 1. The moisture protection membrane 44 can be replaced just like the body for protection against sprayed water 39 and the flame blocking body 11.

[0056] In particular, the drainage openings in the form of edge grooves 42 can be recognized in FIG. 4. These grooves communicate on sides of the flame blocking body 11 with a bunghole 43 in the area of the annular step 36 so that an escape of moisture can take place via bunghole 43 and drainage openings 41 to the outside relative to the pressure relief device 1. This is also shown in particular in FIG. 5 by the corresponding escape arrows 52.

[0057] Certain parts are not shown in the figures for the sake of simplification such as, for example, an additional sealing element which can be arranged between opening edge 8 and the bottom side of the support flange 7.

[0058] The body for protection against sprayed water 39 protects in particular the flame blocking body 11 from outside influences such as moisture and dust or other contaminants. If the body for protection against sprayed water 39 is negatively influenced, for example, by receiving corresponding dust in its porosity, it can be replaced by a new body for protection against sprayed water 39 by simply screwing off the pressure nut 13. At the same time, the invention ensures that the flame blocking body as well as the body for protection against sprayed water can be readily visually checked from the outside and replaced if necessary. The visual checking and replacement can take place independently from one another.

[0059] The assembled pressure relief device according to the invention can also be directly screwed, for example, into a corresponding screw-in opening of a housing, see in this regard the corresponding outer thread in the area of the insertion connecting piece 5. The connection here should be designed to be protected against explosion and in particular pressure-proof.

[0060] In order to improve the freedom of the ignition gap in the edge area in particular of the flame blocking body and optionally also in the area of the body for protection against sprayed water, the edge area can comprise an edge-side pore closure. Furthermore, the body for protection against sprayed water and/or the flame blocking body can be elastic under pressure.

[0061] According to the invention a pressure inside the housing resulting, for example, from an explosion is degraded by the pressure relief device. An explosive atmosphere which may be present outside of the housing is not ignited then since the pressure relief device is designed to be gas-permeable but secure against complete ignition. The pressure relief device according to the invention can also be retrofitted and used for housings which previously used other pressure relief devices. The pressure relief device according to the invention furthermore allows the use of appropriate housings or also of other containers at rather low temperatures. It should be noted here that the explosion pressure rises at rather low temperatures and can also be securely degraded in such an instance by the pressure relief device according to the invention.

[0062] Especially if the pressure relief device is used outside of buildings or in a moist environment and possibly in a dusty environment, it can additionally comprise the intermediate connecting piece and the body for protection against sprayed water. The latter protects the flame blocking body from water and dust. The body for protection against sprayed water comprises to this end drainage openings which remove penetrated moisture or seeped-in water to the outside. In comparison to the body for protection against sprayed water the flame blocking body has as a rule a lesser density so that it can more easily degrade even high pressures by the gas permeability and can at the same time better cool down the possibly hot gases. Both bodies can be readily visually checked and be replaced independently of one another.

[0063] A penetration of moisture in the direction of the flame blocking body can be improved by the additional arrangement of an appropriate moisture protection membrane and at the same time the pressure relief device can be protected regarding a possibly higher load.