referring now to the drawing in detail , and first to fig1 a thereof , it may be seen that the reference numeral 2 a has been used therein to identify a housing of an anti - explosion safety device of the present invention in its entirety . it is to be mentioned at this juncture that in fig1 a to 5 c and the text referring thereto , the corresponding parts of the safety device will be identified with corresponding reference numerals but followed by respective letters consistent with the identification of the various figures , whereas in fig6 to 11 the corresponding parts will be identified by the same reference numerals but with no letter suffixes attached thereto . as shown particularly in fig2 a , an insert 1 a is accommodated , with substantially no leeway , in an internal chamber of a safety device housing 2 a . details of the insert 1 a will be discussed later in conjunction with fig6 to 11 ; for the time being , it will be sufficient to state that the insert 1 a includes a multitude of stacked , as shown superimposed , lamellae . the housing 2 a has a generally rectangular , as shown square , cross - sectional configuration ( see for instance fig4 a ) and so , accordingly , does the internal chamber thereof as well as the stack of lamellae accommodated therein . the internal chamber of the housing 2 a is circumferentially bounded by a sleeve or sheath 3 a that has two axially spaced end portions . a respective one of two end elements 4 a and 5 a is situated at each of the end portions of the sheath 3 a and has a respective peripheral region 6 a and 7 a that extends outwardly beyond the sheath 3 a and is provided with respective through holes 8 a ( shown only in fig1 a ) that are distributed at predetermined intervals over the respective peripheral regions 6 a and 7 a , the associated ones of them being aligned with one another as between the two peripheral regions 6 a and 7 a . a corresponding number of bolts 9 a passes through such mutually aligned holes 8 a and has associated nuts 10 a threaded thereonto such that , when the nuts 10 a are tightened during the assembly of the safety device , the bolts 9 a rigidly and securely connect said end elements 4 a and 5 a , with the sheath 3 a being confined between such connected end elements 4 a and 5 a . each of the end elements 4 a and 5 a is provided with a respective opening 11 a or 12 a that is in communication with the internal chamber containing the insert 1 a and one of which serves as an inlet for the medium into , and the other as an outlet for the medium from , the internal chamber . it may be seen that the end elements 4 a and 5 a are basically mirror images of one another so that the safety device can be considered to be bidirectional in that it can be installed in a pipe system in any one of two orientations , with the opening 11 a serving as the inlet and the opening 12 a as the outlet for the medium in one of these orientations , and vice versa in the other orientation . as shown , the openings 11 a and 12 a are provided in respective cylindrical regions 13 a and 14 a of the associated end elements 4 a and 5 a that are adjoined by respective transitional regions 15 a and 16 a that transition the substantially circular cross - section of the respective cylindrical region 13 a or 14 a into the substantially square ( or , generally speaking , rectangular ) cross - section of the internal chamber containing the insert 1 a . the cylindrical regions 13 a and 14 a serve for the connection of the safety device with consecutive sections of a pipe system . to this end , they may form an assembly with respective flanges 17 a and 18 a ( see fig5 a ) that serve for connection with the aforementioned pipe sections . fig3 a of the drawing shows a modified version of the safety device that includes components identical to those shown in fig2 a except for those identified by respective primes ( i . e . 1 a ′, 3 a ′ and 9 a ′) that differ from those without the primes only in their respective axial lengths . the flow - through construction of the bi - directional safety device of fig1 a to 5 a enables a direct passage of the pressure or surge wave and of the flame through the insert 1 a without encountering any obstacles , with the flame being extinguished in the insert 1 a merely by utilizing the appropriate axial length of the anti - detonation lamellar insert 1 a and its cooling effect on the flame , which is one of the basic parameters for its required function . as a result of the fact that it is possible to install the anti - destination lamellar insert 1 a into the housing 2 a as a single , monolithic , unit having any desired axial length , otherwise needed individual interruptions and connections , which are mandatory in prior safety device constructions and bring into existence respective air pockets with attendant re - initiation of the flame and lowered suppression effect of the device , are avoided in the construction presented here . another embodiment of the safety device of the present invention is shown in fig1 b to 5 b . it is similar to that of fig1 a to 5 a in so many respects that those components thereof that are of the same construction as those discussed in some detail above ( but which , as alluded to above , are provided with letter suffixes b rather than a ) need not be , nor will they be , described in detail again . one important difference , however , is that , because this embodiment of the safety device is intended to be used as an end safety device , the end element 5 b is not a mirror image of the element 5 b ; rather , it has , as visible particularly in fig2 b of the drawing , a flat , ring - like configuration that bounds the outlet opening 12 b for the medium . moreover , unlike the embodiment of fig1 a to 5 a , the embodiment of fig1 b to 5 b is shown to include an outer jacket or casing 19 b that surrounds the sheath 3 b . the advantages of this construction of the end safety device are similar if not identical to those of the bidirectional device discussed above , except that this device is not interposed between two consecutive pipe sections but is located at the end of a pipe or some other conduit . turning now to fig1 c to 5 c , it may be seen there that once more there are certain components of the safety device that are structurally and functionally equivalent to those discussed above ( even though their reference numerals have suffixes c rather than a or b ); they will not be discussed here in any detail because such discussion would be repetitive and hence superfluous . focusing on the differences , it may be observed that this embodiment of the safety device of the present invention is intended for use at location at which the pipe system is to make a turn , as shown , a right - angle turn . for this purpose , the end element 5 c is constructed differently from the end element 4 c in that it includes a superstructure 20 c that carries the cylindrical portion 14 c with the inlet or outlet opening 12 c not in axial alignment with the cylindrical portion 13 c and its opening 11 c but rather at a right angle thereto . the superstructure 20 c carries a control or supervision lid 21 that permits observation of the interior of the housing 2 c and / or introduction of sensors into such interior . here again , the same advantages as those pointed out before accrue , but this time in a device suited to be amployed at a location at which two pipe sections extending at right angles with respect to one another meet . as mentioned before , the insert 1 is of a lamellar construction , including a multitude of lamellae that are stacked in the internal space of the sheath 3 . as shown in fig7 , all of such lamellae 22 have the same dimensions , so that the stack of them has a parallellepiped configuration . yet , in the view presented in fig6 , which is taken through the opening in the only partially shown cylindrical portion 13 of the end element , only those portions of the lamellar 22 that fit into the outline of that opening are visible . each of the lamellae 22 has a generally planar configuration , that is it has a surface 25 ( the bottom surface shown in fig8 ) that extends along a plane . yet the other major surface 26 ( the top surface in fig8 ) of the respective lamella 22 is not planar ; rather , it is provided with a plurality of ribs 23 . now , when the insert 1 is assembled , the lamellae 22 are positioned in the stack in the manner shown in fig7 , that is , all in the same orientation . this results in a situation in which the planar surface 25 of any lamella 22 except that located at the very bottom of the stack is in contact with the ribs 23 of the lamella 22 situated underneath it ; as a result , the surfaces 25 and 26 of these respective two lamellae 22 and the flanks of the ribs 23 together bound respective passages or channels 24 for the flow of the medium therethrough . the lamellae 22 constitute only a minimum impediment to the flow of the medium through the internal space of the housing 2 ( taking into account the fact that the cross - section of the internal space greatly exceeds that of the opening of the end element 13 and is only partially diminished by the presence of the lamellae 22 therein ) during normal operation . however , should an explosion take place in the section of the pipe or other conduit leading toward the safety device , the resultant flame will be extinguished in the passages 24 due , among others , to the cooling effect of the lamellae 22 on the passing medium , provided , however , that the passages 24 are long enough to accomplish this purpose . the length needed for this depends on the characteristic properties of the medium passing through the insert 1 , especially on the temperature of the flame and the speed of the surge wave accompanying or preceding it . an important advantage of the construction in accordance with the present invention is that such length can be easily chosen for the particular medium by appropriately selecting the length of the insert 1 , of the sheath 3 , and of the bolts 9 , without having to change the dimensions or configuration of any other components of the ant - explosion safety device . the lamellae 22 and their ribs 23 can be produced by extrusion , or in a rolling operation . a structure of the insert 1 that does not call for the use of such rather expensive procedures is illustrated in fig1 and 11 of the drawing . it includes completely planar lamellae 27 that alternate in the stack with corrugated elements 28 . in this embodiment , respective passages 29 are formed between the flat lamellae 27 and the corrugations of the associated corrugated elements 28 and have height h and width t . as shown particularly in fig1 , the passages 29 extend over the entire axial length l of the respective corrugated element 28 and thus of the insert 1 . regardless of which construction of the insert 1 described above is chosen for the safety device of the present invention , it has the advantage that , unlike in conventional devices in which the insert is the product of winding with attendant stresses and deformations , the planar configuration of the lamellae 22 or 27 combined with the presence of the ribs 23 or corrugations of the corrugated elements 28 ensures that all of the passages 24 or 29 have the same cross section regardless of their position in the stack , so that they all offer the same resistance to the flow of the medium through them , and the same flame - extinguishing effect in the event that an explosion should occur .
an explosion arresting assembly , especially for use in pipe systems , includes a housing including a sheath circumferentially surrounding an internal chamber and having two axially spaced end regions , two end elements each juxtaposed with one of the end regions of the sheath and each having a portion extending outwardly of the sheath all around the latter and provided with a plurality of circumferentially distributed holes that are aligned with one another as between the two end elements , at least one of the end elements having an opening communicating with said internal chamber , and a plurality of bolts with associated nuts , the bolts passing through the respective aligned ones of the holes , connecting the two end elements with one another and confining the sheath therebetween . an anti - explosion insert including a stack of substantially planar lamellae and integral or separate distancing elements defining respective passages between such lamellae is tightly received in the internal chamber .