EP2332617B1 - Flame barrier for air extraction assemblies - Google Patents

Description

The invention relates to a flame arrester for suction systems for flammable media, in particular for processing facilities, comprising a penetrated by a flow housing, leading into the housing inlet channel and an outgoing from the housing outlet channel. Flammable media may include gaseous flammable fractions or aerosols.

Such flame arresters are known from the prior art, for example DE 741 620 C . GB 363,628 A , and DE 922 756 C ). These are provided within the housing Strömungsumlenkeinheiten, but do not provide reliable protection against penetration of the flame.
The invention is therefore an object of the invention to improve a flame arrester of the generic type such that it represents a reliable protection against penetration of a flame.
This object is achieved according to the invention in a flame arrester of the type described above, that in the housing at least one Strömungsumlenkeinheit is arranged, that the Strömungsumlenkeinheit has a labyrinth wall, which is interspersed by the flow and which deflects the flow several times transverse to its flow direction.
The advantage of this solution is the fact that such a flow deflection unit with a labyrinth wall provides reliable protection against penetration of the flames.
It is particularly advantageous if the flow passing through the labyrinth wall experiences at least a simple Z-shaped deflection in the latter.

This makes it particularly effective to prevent penetration of the flames through the labyrinth wall.

It is further provided that in the at least one Strömungsumlenkeinheit a passing through the labyrinth wall cross flow and an approximately parallel to the labyrinth wall longitudinal flow occurs, so that even the change between the cross flow and the longitudinal flow represents another obstacle to a penetration of the flames.
Appropriately, it is provided that the labyrinth wall at least partially the longitudinal flow leads, that is, that the labyrinth wall on the one hand contributes to the leadership of the longitudinal flow and on the other hand, the cross flow can pass repeatedly deflected.
A particularly favorable solution provides that the longitudinal flow in an interior of the at least one Strömungsumlenkeinheit occurs and is enclosed by the labyrinth wall.
A particularly advantageous solution provides that the longitudinal flow is enclosed on all sides by the labyrinth wall, so that, starting from the longitudinal flow occurring in the interior of the flow deflection unit, an all-round transverse flow is formed which penetrates the labyrinth wall.
A further expedient solution provides that the at least one flow deflection unit converts a longitudinal flow and a transverse flow into one another, that is, at the same time brings about a flow deflection between the longitudinal flow and the transverse flow or the transverse flow and the longitudinal flow in addition to the labyrinth wall.
Appropriately, this is achieved in that the longitudinal flow and the transverse flow can be converted into one another by a deflection wall of the at least one flow deflection unit.

The baffle may be a baffle in the simplest case, but the baffle can also be shaped in adaptation to the flow.

Furthermore, the at least one flow deflection unit is preferably designed such that it has an opening opposite the deflection wall.

In particular, it is favorable if, in the at least one flow deflection unit, an inner longitudinal flow and a transverse flow extending transversely to the latter through the slat wall merge into one another.

Furthermore, it is advantageous if, in the at least one flow deflection unit, a longitudinal flow running along an outer side of the labyrinth wall and the transverse flow passing through the labyrinth wall merge into one another.

With regard to the formation of the labyrinth wall, no further details have been given in connection with the previous explanation.

Thus, an advantageous solution provides that the at least one labyrinth wall has a first set of first lamellae spaced apart to form first flow passage columns, and a second set of second lamellae spaced from the first lamellae to form an intermediate gap which are spaced apart to form second flow passage columns offset relative to the first flow passage columns, and wherein the first and second sets of fins having the first and second flow passage columns and the intermediate gap conduct at least two times a flow incident on the labyrinth wall cause.

The advantage of this design of the labyrinth wall is that it provides an easy way to make the labyrinth wall and give the labyrinth wall the required stability, so that it is also able to pressure fluctuations in the flame arrester, especially when a puncture, as it arises, for example, during a deflagration in the working space of a processing unit, to withstand.

It is particularly advantageous if the labyrinth wall has mutually parallel lamellae.

With regard to the fixation of the slats, no further details were given.

An advantageous solution provides that the lamellae are fixed end.

Another advantageous solution provides that the slats are part of a continuous piece of sheet metal, from which cutouts are punched out for the production of the flow passage column, so that the slats and the slats remain interconnecting and transverse to the slats extending transverse webs. Thus, the lamellae of a set of lamellae all hang together due to the transverse webs, resulting in a very stable structure.

With regard to the shape of the slats, no further details were given in connection with the previous explanation of the individual embodiments.

Thus, an advantageous solution that the slats in cross-section V-shaped or C-shaped, that is, that the slats are not formed of flat material, but have a profile in cross section.

An advantageous solution provides that the lamellae in cross-sectional direction have mutually opposite outer regions which extend at an angle in the range between 40 ° and 110 ° to each other.

With such a course of the outer areas can be achieved in a simple and safe way, a deflection of the flow to the largest possible angle.

Values of the angle between the opposing outer regions in the range of 70 ° to 110 °, even better in the range of 80 ° to 100 °, are preferred.

Furthermore, it is preferably provided that the lamellae have an inner region lying between the outer regions, wherein this inner region can either have a kink or a curvature in order to connect the outer regions extending at an angle to one another.

With regard to the arrangement of the slats relative to each other, no further details were thus given with regard to profiled slats.

An advantageous solution provides that the first fins are arranged with their outer regions facing the second fins.

This means, in particular, that the first lamellae are arranged with their inner regions facing away from the second lamellae.

With regard to the relative arrangement to the second lamellae, it is particularly advantageous if the first lamellae are arranged with their outer regions facing inner regions of the second lamellae, so that the first lamellae and the second lamellae are arranged offset to one another.

Furthermore, no details were given regarding the orientation of the second lamellae.

For example, it would be conceivable to arrange the second slats aligned in the same way as the first slats.

In order to achieve a particularly favorable and large flow deflection in the labyrinth wall, however, it has proven to be particularly advantageous if the second slats are arranged with their outer areas facing the first slats, that is, in principle, have the reverse orientation as the first slats.

For example, in this case also the second slats are aligned so that they are arranged with their inner regions facing away from the first slats.

A particularly favorable relative arrangement of the second lamellae to the first lamellae results when the second lamellae are arranged with their outer regions facing inner regions of the first lamellae, so that in this regard the desired offset between the first and the second lamellae is ensured.

A further advantageous embodiment of the flame arrester according to the invention provides that a flow cross-sectional area in an interior of the at least one flow deflection unit essentially corresponds to a flow cross-sectional area of the labyrinth wall, so that the labyrinth wall ultimately does not represent a flow obstacle for the flow through it, but in the same way and with the same pressure drop can be flowed through, as the interior of the Strömungsumlenkeinheit.

Furthermore, it is preferably provided that a flow cross-sectional area surrounding the at least one flow deflection unit in the housing substantially corresponds to the flow cross-sectional area in the interior of the flow deflection unit, so that after passing through the labyrinth wall of the flow in the housing and between the housing and the labyrinth wall the same flow cross-sectional area is available and thus neither acceleration nor a delay of the flow occurs.

With regard to the efficiency of the flame arrester, it is further preferably provided that the flame arrester has at least one expansion space associated with the at least one flow deflection unit, in which the flow cross-sectional area is greater than the flow cross-sectional area of the at least one flow deflection unit. Such an expansion space, which is associated with the at least one Strömungsumlenkeinheit, creates the possibility to achieve an additional delay of the flow and thus also represent another obstacle to a breakthrough of a flame through the flame arrester.

The expansion space can be assigned to the Strömungsumlenkeinheit in various ways.

An advantageous solution provides that an expansion space is provided downstream of the at least one Strömungsumlenkeinheit.

Alternatively or additionally, another advantageous solution provides that an expansion space is provided upstream of the at least one flow deflection unit.

A further improved effect of the flame arrester according to the invention can be achieved, in particular, by providing a plurality of flow deflection units in the housing, so that an improved dielectric strength for the flame can likewise be achieved by the plurality of flow deflection units.

Preferably, each of the flow diverters is associated with an expansion space that may be provided either upstream or downstream of this flow diverter.

In connection with the previous explanation of the flame arrester according to the invention, only the flame-extinguishing property of the flow deflection units and the expansion chambers has been discussed.

A further advantageous embodiment, however, provides that the flame arrester is provided with at least one cooling element.

In the simplest case, such a cooling element can only contribute, due to its mass, to additionally cool the flame and thus to cause it to extinguish.

Preferably, the flame is also already cooled by the at least one flow deflection unit according to the invention, wherein the cooling effect can still be improved by the at least one additional cooling element.

Such an additional cooling element is formed, for example, by one or more cooling fins, along which the medium flows, wherein the medium emits heat to the cooling fins in order to cool.

In the simplest case, the cooling fins are then provided due to their mass with such a large heat capacity that they can absorb enough heat energy in the event of a flame hammering into the flame arrester to cool the flame to the desired extent.

Preferably, the cooling fins are heated to a maximum of 100 ° C., more preferably a maximum of 60 ° C., with a flame striking the flame arrestor, so that the mass of the cooling fins, which are made, for example, of a material of high Heat capacity, in the simplest case steel, are dimensioned accordingly.

A further advantageous embodiment of a flame arrester according to the invention provides that at least one expansion space is effective for the separation of impurities carried by the medium, for example chips or other particles or oil droplets entrained by the medium, so that in particular when the deposition is present a Strömungsumlenkeinheit invention takes place already contamination of the Strömungsumlenkeinheit itself can be either reduced or avoided.

It is particularly expedient here if the expansion space for the separation of impurities carried by the medium is arranged upstream of the first flow deflection unit.

It is particularly advantageous if the expansion space for depositing carried by the medium impurities in the vertical direction below the first Strömungsumlenkeinheit is arranged so that even the effect of gravity to improve the deposition of the medium carried impurities can be used before these can reach downstream Strömungsumlenkeinheit.

A further advantageous embodiment of the flame arrester according to the invention provides that the flame arrester is provided with a shut-off device.

Such a shut-off device serves to ensure that in the event of a fire in the working space and a flame striking the flame and a subsequent deletion of the fire in the working space medium is sucked from the working space to leave the extinguishing medium in the working space, so that it is its extinguishing Effect can fully develop.

Such a shut-off device is controlled, for example, either by the control of the processing device or by a separate control that reacts to a fire in the working space of the processing device and at the latest when using an extinguishing medium in the working space further absorption of medium prevented by the flame arrester.

Thus, there is only the need to interpret the flame arrester so that it is able to prevent the penetration of a flame until the suction of the medium is prevented by the shut-off device.

This is particularly important in terms of heat extraction of the flame of importance, since in this case the elements that are to remove heat from the flame, for example, the masses of the Strömungsumlenkeinheiten and possibly existing cooling elements in terms of their heat capacity must be dimensioned only so that they during the period , up to which the shut-off device has completely interrupted the suction of the medium, contribute to the extinguishment of the flame and prevent penetration of the flame by the flame arrester.

Further features and advantages of the invention are the subject of the following description and the drawings of some embodiments.

Fig. 1

eine schematische Darstellung einer Bearbeitungseinrichtung mit einer Absauganlage;

Fig. 2

eine perspektivische Darstellung eines ersten Ausführungsbeispiels einer erfindungsgemäßen Flammensperre mit gestrichelt angedeuteten, im Inneren derselben angeordneten Strömungsumlenkeinheiten;

Fig. 3

einen Schnitt längs Linie 3-3 in Fig. 2;

Fig. 4

einen Schnitt längs Linie 4-4 in Fig. 2;

Fig. 5

eine ausschnittsweise vergrößerte Darstellung eines Bereichs X in Fig. 4;

Fig. 6

eine Darstellung ähnlich Fig. 2 eines zweiten Ausführungsbeispiels einer erfindungsgemäßen Flammensperre;

Fig. 7

einen Schnitt ähnlich Fig. 3 durch das zweite Ausführungsbeispiel der erfindungsgemäßen Flammensperre und

Fig. 8

einen Schnitt ähnlich Fig. 3 durch ein drittes Ausführungsbeispiel einer erfindungsgemäßen Flammensperre;

Fig. 9

eine Gesamtansicht eines vierten Ausführungsbeispiels einer erfindungsgemäßen Flammensperre;

Fig. 10

einen Schnitt längs Linie 10-10 in Fig. 9;

Fig. 11

einen Schnitt längs Linie 11-11 in Fig. 10;

Fig. 12

einen Schnitt längs Linie 12-12 in Fig. 10;

Fig. 13

einen Schnitt längs Linie 13-13 in Fig. 10;

Fig. 14

einen Schnitt längs Linie 14-14 in Fig. 10;

Fig. 15

eine Draufsicht in Richtung eines Pfeils A in Fig. 10 bei fehlendem Gehäuseboden.

In the drawing show:

Fig. 1

a schematic representation of a processing device with a suction system;

Fig. 2

a perspective view of a first embodiment of a flame arrester according to the invention with dashed lines indicated, arranged in the interior of the same Strömungsumlenkeinheiten;

Fig. 3

a section along line 3-3 in Fig. 2 ;

Fig. 4

a section along line 4-4 in Fig. 2 ;

Fig. 5

a detail enlarged view of a region X in Fig. 4 ;

Fig. 6

a representation similar Fig. 2 a second embodiment of a flame arrester according to the invention;

Fig. 7

similar to a cut Fig. 3 by the second embodiment of the flame arrester according to the invention and

Fig. 8

similar to a cut Fig. 3 by a third embodiment of a flame arrester according to the invention;

Fig. 9

an overall view of a fourth embodiment of a flame arrester according to the invention;

Fig. 10

a section along line 10-10 in Fig. 9 ;

Fig. 11

a section along line 11-11 in Fig. 10 ;

Fig. 12

a section along line 12-12 in Fig. 10 ;

Fig. 13

a section along line 13-13 in Fig. 10 ;

Fig. 14

a section along line 14-14 in Fig. 10 ;

Fig. 15

a plan view in the direction of an arrow A in Fig. 10 in the absence of caseback.

An in Fig. 1 illustrated embodiment of a processing device 10 according to the invention comprises a housing 12 which encloses a working space 14 in which a machining of a workpiece takes place.

In the working space 14, either a flammable gaseous medium is present or can form a flammable gaseous medium, for example by atomized cooling lubricant or other media.

Usually, a part of the same is sucked out of the working space 14 for exchanging the gaseous medium via an extraction system 20, which has a fan 22, which is provided in a channel system 24, which in turn leads from the working space 14 to an outlet 26.

In this case, filter and separation units 28 may be provided in the channel system 24, which are connected upstream of the blower 22, for example.

In order to prevent a fire in the channel system 24 and possibly the filter and separation units 28 in the case of an inflammation of the gaseous and / or aerosol-containing medium in the working space 14, in the channel system 24 of the suction unit 20, preferably near the working space 14, for example arranged above the processing device 10, designated as a whole with 30 flame arrester, which is able to prevent a breakthrough of a flame from the working space 14 in the channel system 24.

Preferably, the flame arrester 30 is seated following an intake manifold 32 led out of the working space 14 of the exhaust system 20.

An in Fig. 2 illustrated first embodiment of the flame arrester 30 includes a housing 40 which encloses a housing interior 42 in which a first flow deflecting unit 44 and a second flow deflecting unit 46 are arranged.

Preferably, the housing 40 is formed by a cylindrical shell 52 which is closed by end walls 54 and 56, wherein the cylindrical shell extends along a central axis 58.

The cylindrical jacket 52 can have either a circular cylindrical or an elliptical or an angular, for example, a polygonal, cross-sectional shape.

The arranged in the housing interior 42 first flow deflecting unit 44 encloses an inner space 60 which is connected to an inlet channel 62, which passes through the end wall 54 of the housing 40 and in turn is connected to the intake manifold 32.

As in Fig. 3 shown, enters through the inlet channel 62 from the working chamber 14 via the intake manifold 32 sucked medium in the form of a longitudinal flow 64 in the interior 60 of the first Strömungsumlenkeinheit 44 and is deflected due to a the inlet channel 62 opposite baffle 66 in a cross-flow 68, the one the labyrinth wall 70 extends in continuation of a channel wall 72 of the inlet channel 62 and thus provides a flow cross-sectional area Q1 for the longitudinal flow 64 in the interior of the first flow deflection unit 44, the at least the flow cross-sectional area QE of the inlet channel 62 corresponds.

The first flow deflection unit 44 is thus preferably formed by the labyrinth wall 70 and the deflection wall 66 extending cylindrically in continuation of the inlet channel 62, wherein, for example, the labyrinth wall 70 is held on the end wall 54 of the housing 40 and also the inlet channel 62 likewise on the end wall 54 is held, which has one of the flow cross-sectional area QE corresponding breakthrough.

The labyrinth wall 70 itself has a flow cross-sectional area QL1 which substantially corresponds to the flow cross-sectional area Q1.

After passing through the labyrinth wall 70, the cross flow 68 outside the first flow deflection unit 44 again undergoes a deflection through the casing 52 of the housing, so that around the first flow deflection unit 44 again a longitudinal flow 74 with an annular flow cross-sectional area QR1, which substantially corresponds to the flow cross-sectional area Q1 , which opens into a following in the direction of the center axis 58 on the first flow deflection 44 following the first expansion space 76, which provides a flow cross-sectional area QX1 that is greater than the flow cross-sectional areas QE in the inlet channel 62, preferably twice as large as the flow cross-sectional area QE and / or the flow cross-sectional area Q1 in the first flow deflection unit 44.

The first expansion space 76 is separated from a second expansion space 86 by an aperture 80, generally indicated at 80, which follows the first expansion space 76 in the direction of the center axis 58 and provides a flow cross-sectional area QX2 substantially equal to that of FIG Flow cross-sectional area QX1 corresponds.

The resulting in the region of the first Strömungsumlenkeinheit 44 annular longitudinal flow 74 now flows through the first expansion chamber 76, the passage opening 82 of the aperture 80 and the second expansion space 86, due to the expansion in the first expansion space 76 and the second expansion space 86 and the cross-sectional constriction through the aperture 80th a Strömungsverwirbelung takes place.

Finally, the longitudinal flow 74 reaches the second flow deflection unit 46 and flows around it annularly on its outer side facing the jacket 52 of the housing 40, which is formed by a labyrinth wall 90 a flow cross-sectional area QR2 which substantially corresponds to the flow cross-sectional area QR1, wherein a deflection of the longitudinal flow 74 into a labyrinth wall 90 with a flow cross-sectional area QL2, which corresponds approximately to the flow cross-sectional area QL1, passing cross-flow 92 is carried out in an inner space 100, of the labyrinth wall 90 and a deflection wall 96 is enclosed, is again deflected into a longitudinal flow 94, which in turn exits through an outlet channel 102 from the flame arrester 30, wherein the outlet channel 102 is connected to the channel system 24.

Also in the second flow deflection unit 46, the labyrinth wall 90 extends in continuation of a channel wall 112 of the outlet channel 102 and has a flow cross-sectional area Q2 which is at least as large or larger than a flow cross-sectional area QA of the outlet channel 102 and approximately corresponds to the flow cross-sectional area Q1.

In this case, the labyrinth wall 90 is held on the end wall 56 and also the channel wall of the outlet channel 102 in the second Strömungsumlenkeinheit 46.

Preferably, the flow cross-sectional area Q1, Q2, QL1, QL2, QR1, QR and QA are at least as large as the flow cross-sectional area QE and the flow cross-sectional area QX1 and QX2 are at least 1.5 times greater than QE, more preferably at least twice as large as QE.

As in Fig. 4 and Fig. 5 illustrated, each of the labyrinth walls 70 and 90, exemplified using the example of the labyrinth wall 70, a first set 120 of first fins 122, wherein the fins 122 of the first set 120 are spaced apart, so that in each case between successive first fins 122 of first set 120 first flow passage column 124 arise.

In this case, the first fins 122 are formed as extending in the direction of the central axis 58 elongated profiled strip elements having transversely opposed outer regions 126 and 128, which are connected by a curved inner region 130, wherein the outer regions 126 and 128, for example, at an angle of approximately 90 ° to each other and the inner region 130 connects at an angle of approximately 90 ° to each other outer regions 126 and 128 with each other.

The first fins 122 of the first set 120 of fins are facing with their outer regions 126, 128 a second set 140 of second fins 142, wherein the second fins 142 of the second set 140 are spaced from each other, so that between each successive second fins 142 of the second set 140 second flow passage column 144 form.

The second lamellae 142 also have profiled transversely opposite outer regions 146 and 148, which are interconnected by an inner region 150, wherein also in the second fins 142, the outer regions 146 and 148 extend at an angle of approximately 90 ° to each other and through the curved inner region 150 are interconnected.

Further, the first fins 122 and the second fins 142 are staggered relative to each other so that the first flow passage nips 124 face curvature inner sides 152 of the second fins 142 and also so that the second flow passage nips 144 face curvature inner sides 132 of the first fins 122.

The first fins 122 and the second fins 142 are, as in Fig. 5 represented, arranged at such a distance from each other, that between the opposing outer regions 126 and 148 or 128 and 146, a third flow passage gap 160 occurs, which allows a flow 170, the first flow passage gap 124 or the second flow passage gap 144 interspersed between the both sides of the same arranged outer regions 126 and 128 and the These opposite outer regions 148 and 146 can pass, in turn, then to have the opportunity to pass through the flow passage gap 144 and 124 and thus exit from the labyrinth wall 70 and 90, respectively.

That is, each of the labyrinth walls 70, 90 faces either an outer curvature 134 side of the inner region 130 or an outer curvature 154 side 154 of the inner region 150, depending on whether the flow 170 is first on the first set 120 or first on the first second set 140 of lamellae.

Independently of this, the respective outer curvature side 134 or 154 of the first fins 122 and second fins 142 causes a deflection of the flow in the direction of the first flow passage gaps 124 and second flow passage gaps 144, respectively.

After passing through the first flow passage column 124 and the second flow passage column 144, the flow is deflected by the curvature inner side 152 or 132 of the respective other fins 142 and 122, in the direction of the curvature inner side 132 or curvature inner side 152, and can then proceed from this Curved inner side 132 or curvature inner side 152 in turn pass through the respective other flow passage gap 144 and 124, respectively.

In total, therefore, a flow 170 passing through the labyrinth wall 70 or 90 runs Z-shaped and undergoes a double deflection, which totals in total to a deflection of at least approximately 270 °. By taking place in the labyrinth wall 70 and 90 Z-shaped deflection of a flow 170 is a penetration of a flame through such a labyrinth wall 70, 90 effectively prevents, in particular, if this flow 170 in advance still a deflection of the longitudinal flow 64 in the flow 170 forming transverse flow 68 or from the longitudinal flow 74 in the flow 170 forming transverse flow 92 precedes and / or on the flow 170 forming transverse flow 68 or 92 nor a deflection into a longitudinal flow 74 and 94 follows.

Thus, the flow deflection units 44 and 46 by the deflection between longitudinal flows 64, 74, 94 and cross flows 68, 92 in conjunction with the flow through the respective labyrinth wall 70 and 90 already provide effective protection against the penetration of a flame at different flow velocities.

This effective protection against flame penetration is further enhanced by the provision of two expansion spaces 76 and 86 between the flow diverting units 44 and 46, in which the flow is slowed down due to expansion and thus a rapid spread of the flame is prevented.

In a second embodiment of a flame arrester 30 'according to the invention, shown in FIG Fig. 6 and 7 In contrast to the first exemplary embodiment, the flow deflection units 44 and 46 are not arranged immediately adjacent to the inlet channel 62 and the outlet channel 102, but the inlet channel 62, with the flow cross-sectional area QE, opens into the housing 40 'into a first expansion space 180 with the flow cross-sectional area QX1 , flows from this, the first Strömungsumlenkeinheit 44 with the flow cross-sectional area QR1 on its outer side and passes through the labyrinth wall 70 with the flow cross-sectional area QL1 in the interior 60 of the first flow deflection unit 44 with the flow cross-sectional area Q1 in a second expansion space 182 with the flow cross-sectional area QX2 enter, which is disposed between the first flow diverter 44 and the second flow diverter 46.

From the second expansion space 182, the flow again enters the interior 100 of the second flow deflection unit 46 with the flow cross-sectional area Q2, passes through its labyrinth wall 90 with the flow cross-sectional area QL2 and flows with the flow cross-sectional area QR2 on an outside of the second flow deflection 46 into a third expansion space 184 the flow cross-sectional area QX3, starting from which the flow enters the outlet channel 102 with the flow cross-sectional area QA.

Preferably, the flow cross-sectional areas Q1, Q2, QL1, QL2, QR1, QR2 and QA are at least as large as QE and the flow cross-sectional area QX1, QX2 and QX3 greater, preferably at least 1.5 times as large as QE.

For this purpose, the first flow deflection unit 44 is arranged so that the deflection wall 66 thereof faces the inlet channel 62 and the second flow deflection unit 46 is arranged so that its deflection wall 96 faces the outlet channel 102.

Further, the first flow diverter 44 is supported on an annular wall 192 which extends from and supports the shell 52 of the housing 40 'to the labyrinth wall 70 while the interior 60 of the first flow diverter 44 is open on its side facing the second expansion chamber 182 such that the interior 60 of the first flow deflection unit 44 merges with its entire flow cross-sectional area Q1 into the second expansion space 182.

Similarly, the second Strömungsumlenkeinheit 46 is held on an annular wall 194, which also extends from the shell 52 of the housing 40 'radially inwardly and the labyrinth wall 90 of the second flow diverter 46. Thus, the interior 100 of second Strömungsumlenkeinheit 46 with its full flow cross-sectional area Q2 on its side facing the second expansion chamber 182 side in the second expansion space 182, which is thus bounded on the one hand by the ring walls 192 and 194 and the first Strömungsumlenkeinheit 44 and the second Strömungsumlenkeinheit 46.

Incidentally, in the second embodiment, those parts which are identical to those of the first embodiment are provided with the same reference numerals, so that with regard to the detailed description of the same, reference may be made in full to the comments on the first embodiment.

In the second embodiment, there is the advantage that the number of expansion spaces 180, 182, 184 is greater than in the first embodiment, and thus the safety with respect to flame penetration is still increased in relation to the first embodiment.

At an in Fig. 8 illustrated third embodiment of a flame arrester 30 "according to the invention, the first Strömungsumlenkeinheit 44 is arranged in the same manner as in the first embodiment, that in the interior 60 of the inlet channel 62 opens, so that the flow from the inner space 60 through the labyrinth wall 70 passes through to the outside and, in contrast to the first embodiment, enters and expands in a first expansion space 200 around the first flow deflection unit 44 with the flow cross-sectional area QRX1.

In addition, the first expansion space 200 also encloses a third flow deflection unit 45, which is arranged directly following the first flow deflection unit 44 and designed accordingly, and in which the flow through the labyrinth wall 71 enters an interior 61 thereof.

In alignment with the third flow deflection unit 45 there is provided a fourth flow deflection unit 47, corresponding to the second flow deflection unit 46, into whose interior 101 the flow enters from the interior 61 of the third flow deflection unit 45, so that the flow then starts from the inner space 101, the labyrinth wall 103 fourth flow deflection unit 47 passes through and enters a second expansion space 202 with the flow cross-sectional area QRX2, which encloses both the fourth Strömungsumlenkeinheit 47 and the second flow diverter 46.

From the second expansion space 202, the flow through the labyrinth wall 90 of the second flow deflection unit 46 can enter into the interior 100 of the latter and in turn enter the exit channel 102, as described in connection with the first exemplary embodiment.

The first expansion space 200 and the second expansion space 202 are still separated from each other by an annular wall 210 which extends radially inwardly from the shell 52 of the housing 40 "to the labyrinth walls 71 and 103 of the third flow deflection unit 45 and the fourth flow deflection unit 47, respectively extends and carries the labyrinth walls 71 and 103, respectively.

Furthermore, the labyrinth walls 71 and 103 on the side of the first flow deflecting unit 44 and the second flow deflecting unit 46 directly adjoin and are also held by the deflecting walls 66 and 96, respectively.

In the third embodiment, the flow cross-sectional areas Q1, Q2, QL1, QL2 and QA are at least as large as QE and the flow cross-sectional areas QRX1 and QRX2 are at least 1.5 times as large as QE or at least twice as large as QE.

The advantage of the third embodiment can be seen in the fact that in this case the number of flow deflection units 44, 45, 46, 47 is substantially increased compared to the first or second embodiment and also the respective expansion space 200 or 202 adjoins it directly outside, so that the security against penetration of a flame in this embodiment is still significantly higher than in the first or second embodiment.

Incidentally, even in the third embodiment, those parts which are identical to those of the first embodiment are provided with the same reference numerals, so that reference may be made to the contents of the first or second embodiment.

In a fourth embodiment of a flame arrester 30 'according to the invention "shown in the FIGS. 9 to 15 the housing 40 '"is formed as a parallelepiped body 220 and has an inlet side wall 222, an outlet side wall 224 opposite thereto, two side walls 226 and 228 extending between the inlet side wall 222 and the outlet side wall 224, a bottom 230, and a cover hood 232 on.

In the inlet side wall 222 of the inlet channel 62 is provided and in the outlet side wall 224 of the outlet channel 102, so that an installation of the fourth embodiment of the flame arrester 30 'invention can be done in a similar manner, as in Fig. 1 represented and related to Fig. 1 described.

At the fourth, in Fig. 9 to 15 1, the flow entering the housing 40 '"is first deflected by a deflection wall 238 into a first expansion space 240, in which a significant expansion of the medium from the flow cross-sectional area QE to a flow cross-sectional area QXA1 occurs, whereby the expansion of the medium is so great that that in the first expansion space 240 not only a relaxation of the medium can take place, but also a deposition of borne by the medium impurities, such as oil droplets, chips or other particles, which settle in the first expansion space 240 following gravity and on the bottom 230 of the housing 40 '"then accumulate.

From the first expansion space 240, the medium flows in a similar manner as in the preceding embodiments, but opposite to gravity, in the Strömungsumlenkeinheit 44 from a bottom 230 facing side as a longitudinal flow 64 and is in the interior 60 into the cross flow 68th deflected, since the first Strömungsumlenkeinheit 44 is closed on one of its the bottom 230 opposite side by the deflection wall 66, as explained for example in connection with the first embodiment.

After passing through the labyrinth wall 70 of the first flow diverter 44, the medium having a flow cross-sectional area QR1 '"continues along the labyrinth wall 70 towards the cover 232 of the housing 40"', the cover 232 forming in its interior a second expansion space 242 whose flow cross-sectional area QXK1 is larger than the flow cross-sectional area Q1 in the first flow deflecting element 44.

However, the cover 232 includes not only the second expansion space 242 but, as in FIG Fig. 11 . 12 and 13 illustrated, parallel to a flow direction of the medium extending cooling fins 244, which cool down along this flowing medium to promote by lowering the temperature, the extinction of a striking flame.

The cover 232 engages over a partition wall 246 which, together with the deflection wall 238 and the side walls 226 and 228, defines a flow space 248 which communicates with the flow cross section QR1 '" Medium in the cover 232 and thus in the second expansion space 242 leads.

From the second expansion space 242, the medium, after flowing through a passage opening 250, enters a third expansion space 252 provided in the cover hood 232 and is deflected by the latter into a flow space 254 surrounding the second flow deflection unit 46, in which it extends along the labyrinth wall 90 of the second flow deflection unit 46 flows through and flows through the labyrinth wall 90 in an inner space 100 of the second flow deflection 46th

To flow through the labyrinth wall 90, a deflection of the flow into the cross flow 92, which passes through the labyrinth wall 90, so that the flow of the medium from the interior 100 of the second flow deflection 46 may enter a fourth expansion space 260 which between the second flow deflection 46 and the bottom 230 is arranged and from which starting the medium can enter the outlet channel 102, which in the outlet-side wall 224 of the housing 40 '"is arranged.

The flow cross-sectional area QX4 in the fourth expansion space 260 is greater than the flow cross-sectional areas QXK1 and QXK2 of the second expansion space 242 and the third expansion space 252 and approximately comparable to the flow cross-sectional area QXKA1 in the first expansion space 240.

Moreover, in the fourth expansion space 260, as in FIG Fig. 13 and 15 shown, a shut-off device 270 is provided which, for example, has a 272 pivotable about an axis flap 274, with which the outlet channel 102 is partially closed for throttling the flow but also completely for interrupting the flow of the medium.

For this purpose, the shut-off device 270 is provided with a drive unit 276, with which the closure flap 274 can be brought either into the position restricting the flow through the flame arrestor or into a position completely blocking the flow through the flame arrester 30 '".

The drive unit 276 can be controlled, for example, by a control of the processing device 10, if it is constructed so that it detects a fire in the working space 14 or by a separate and the working space 14 of the processing device 10 associated fire detection device.

The advantage of the fourth embodiment of the flame arrester 30 '"according to the invention is to be seen in that a separating function is integrated into this by the very large first expansion space chosen 240, characterized in that in the first expansion space 240 due to the extreme slowing down of the flow of the medium in the As already described, it is possible to separate impurities carried by the medium, such as oil droplets, chips or other particles, advantageously the first expansion space 240 being arranged vertically below the first flow deflection unit 44, thus minimizing the impurities carried by the medium before flowing through the first flow deflection unit 46 to a considerable extent, if not to a large extent, to be able to separate.

Furthermore, in the fourth embodiment, the labyrinth wall 70 extends substantially in the vertical direction or inclined at a maximum angle of 45 °, more preferably at an angle of less than 30 ° to the vertical, more preferably less than 20 ° to the vertical, so that on the labyrinth wall 70 also impurities, such as liquids, such as oil or cooling lubricant emulsion, deposit, which then follow the gravity along the labyrinth wall 70 down and drain into the first expansion space 240.

In order to remove impurities separating in the first expansion space 240 and also from the first flow deflection unit 44 running or falling and thereby entering the first expansion space 240 impurities, the housing 40 "is provided in the region of the first expansion space 240 with an access door 236 having an access to the first expansion space 240 for cleaning the same creates.

Due to the fact that the second expansion space 242 and the third expansion space 250 are provided with cooling fins along which the medium flows when covering hood 232 flows, an additional cooling of the medium takes place in addition to the cooling already effected by the first flow deflection unit 44 and in particular the labyrinth wall 70 Housing cap 232 with simultaneous relaxation of the flowing medium in both the second expansion chamber 242 and the third expansion chamber 252, before the medium enters the flow space 254, on the one hand along the labyrinth wall 90 and the other through the labyrinth wall 90 of the second flow deflection unit 46 through enter and enter the interior 100 of the second flow diverter 46 and then pass from this into the fourth expansion space 260, in which the shut-off device 270 is arranged with the closure flap 274.

The arrangement of the fourth expansion chamber 260 and the exit channel 102 vertically below the second flow diverter 46, as selected in the fourth embodiment, further complicates the penetration of the flame into the exit passage 102 because the hot gas of the flame tends to rise vertically rather than downwardly ,

By means of the shut-off device 270 integrated into the flame arrester 30 '"according to the fourth exemplary embodiment, it is possible in simple manner to adjust the mass flow of the medium through the flame arrestor 30''and, on the other hand, in the event of a fire in the working space 14 to flow through the flame arrester 30 prevent and thus prevent penetration of the flames in the channel system 24. In addition, the cooling fins 244 in the housing cover 232 in conjunction with the labyrinth walls 70 and 90 cause a strong cooling of the medium, so that already extinguished due to the strong cooling usually the flame.

The heat capacity of the labyrinth walls 70 and 90 as well as the entirety of the cooling ribs 244 is designed so that, as long as there is even a flame in the flame arrester 30 '", to less than 100 ° C, even better less than 60 ° C. heat and thus act so strongly cooling on the flame, that a flame in the flame arrester 30 '"does not beat through this and enters the outlet channel 102, but due to the expansion, the turbulence and also the cooling by the labyrinth walls 70 and 90 and the cooling fins 244 extinguishes in one of the expansion spaces 240, 242, 252 or at the latest in the expansion space 260.

Incidentally, in the fourth embodiment, those parts which are identical to those of the first and second or third embodiment are given the same reference numerals, so that with respect to the description of the same, reference can be made to the explanations of these preceding embodiments.

Claims (16)

1. Flame barrier (30) for air extraction assemblies (20) for flammable media, in particular for machining devices, comprising a housing (40) with a flow of medium passing through it, an entry channel (62) leading into the housing and an exit channel (102) leading out of the housing (40),
   characterized in that at least one flow deflection unit (44, 45, 46, 47) is arranged in the housing (40), that the at least one flow deflection unit (44, 45, 46, 47) has a labyrinth wall (70, 71, 90, 91), that a cross flow (68, 92, 170) passing through the labyrinth wall (70, 71, 90, 91) and a longitudinal flow (64, 94) running approximately parallel to the labyrinth wall (70, 71, 90, 91) occur in the at least one flow deflection unit (44, 45, 46, 47), and that the cross flow (68, 92, 170) impinging on the labyrinth wall (70, 71, 90, 91) passes through said wall, and that the labyrinth wall (70, 71, 90, 91) deflects the flow (68, 92, 170) impinging on it multiple times transversely to its direction of flow.
2. Flame barrier as defined in claim 1, characterized in that the flow passing through the labyrinth wall (70, 71, 90, 91) experiences in it at least one simple Z-shaped deflection.
3. Flame barrier as defined in claim 1 or 2, characterized in that the longitudinal flow (64, 94) is enclosed on all sides by the labyrinth wall (70, 71, 90, 91).
4. Flame barrier as defined in any one of the preceding claims, characterized in that the at least one flow deflection unit blends a longitudinal flow (64, 94) and a cross flow (68, 92) into one another.
5. Flame barrier as defined in any one of the preceding claims, characterized in that the at least one labyrinth wall (70, 71, 90, 91) has a first set (120) of first fins (122) arranged at a distance from one another, thereby forming first flow passages (124), as well as a second set (140) of second fins (142) arranged at a distance from the first fins (142), thereby forming an intermediate gap (160), said second fins being arranged at a distance from one another, thereby forming second flow passages (144) offset relative to the first flow passages (124), and that with the first (124) and second (144) flow passages as well as the intermediate gap (160) the first (120) and the second (140) sets of fins cause an at least twofold deflection of a flow (170) impinging on the labyrinth wall (70, 71, 90, 91).
6. Flame barrier as defined in any one of the preceding claims, characterized in that the labyrinth wall (70, 71, 90, 91) has fins (122, 142) running parallel to one another.
7. Flame barrier as defined in claim 5 or 6, characterized in that the fins (122, 142) are fixed at their ends.
8. Flame barrier as defined in any one of claims 5 to 7, characterized in that the fins (122, 142) are of a V-shaped or C-shaped design in cross section.
9. Flame barrier as defined in any one of claims 5 to 8, characterized in that the first fins (122) face the second fins (142) with their outer areas (126, 128) and that the first fins (122) are arranged, in particular, with their outer areas (126, 128) facing inner areas (150) of the second fins.
10. Flame barrier as defined in any one of claims 5 to 9, characterized in that the second fins (142) face the first fins (122) with their outer areas (146, 148) and that the second fins (142) are arranged, in particular, with their outer areas (146, 148) facing inner areas (130) of the first fins (122).
11. Flame barrier as defined in any one of the preceding claims, characterized in that a flow cross-sectional surface area (Q1, Q2) in an interior (60, 100) of the flow deflection unit (44, 45, 46, 47) corresponds essentially to a flow cross-sectional surface area (QL1, QL2) of the labyrinth wall (70, 71, 90, 91).
12. Flame barrier as defined in any one of the preceding claims, characterized in that a flow cross-sectional surface area (QR1, QR2) surrounding the at least one flow deflection unit (44, 45, 46, 47) corresponds essentially to the flow cross-sectional surface area (Q1, Q2) in the interior (60, 100) of the flow deflection unit (44, 45, 46, 47).
13. Flame barrier as defined in any one of the preceding claims, characterized in that the flame barrier (30) has at least one expansion chamber (76, 86, 180, 182, 184, 200, 202, 240, 242, 252, 260) associated with the at least one flow deflection unit (44, 45, 46, 47), the flow cross-sectional surface area (Q1, Q2) in said expansion chamber being greater than the flow cross-sectional surface area (Q1, Q2) in the interior (60, 100) of the at least one flow deflection unit (44, 45, 46, 47).
14. Flame barrier as defined in any one of the preceding claims, characterized in that the flame barrier is provided with at least one cooling element (244).
15. Flame barrier as defined in any one of the preceding claims, characterized in that at least one expansion chamber (240) is operative for the separation of impurities carried in the medium.
16. Flame barrier as defined in any one of the preceding claims, characterized in that this is provided with a shut-off device (270).

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