FR2532557A1 - DESICCATION DEVICE FOR A COMPRESSED AIR BRAKE AIR DRYER - Google Patents

Abstract

TO FACILITATE THE RENEWAL OF THE DESICCANT 14, WHICH MUST BE DONE ONCE A YEAR FOR EXAMPLE, AND AT THE SAME TIME TO SIMPLIFY THE CONSTRUCTION OF THE DESICCANT, THE DESICCANT IS CONTAINED IN A CYLINDER10 WHICH IS SIMPLY SCREWED BY A TUBING OF THE BODY19 ON A BODY TUBING19 BODY OF DESICATOR. THE POT10 WITH ITS CONTENTS IS DISCARDED AND REPLACED BY A NEW POT AT THE ANNUAL MAINTENANCE OPERATION. THE AIR TO BE DEHYDRATED ENTERED THROUGH ORIFICES24 OF A LID15 FORMING THE POT AT ONE END. IT PASSES THROUGH THE DESICCANT 14, WHICH IS COMPRESSED BY A SPRING38, AND SPRING FROM THE POT THROUGH A TUBE27 AND AN OUTLET 18 COMMUNICATING WITH AN AIR CHANNEL OF THE DESICATOR.

Description

1- The invention starts from a desiccation device for desiccators

  of air intended for compressed air installations supplied by a compressor and having a compressed air reservoir, in particular for vehicle air brakes, comprising a container loaded with a dehydrating or dehydrating product, which is preferably left regenerate, and provided at one end with a central outlet opening for dry air, the air to be dehydrated penetrating through orifices in the container and passing through the desiccant inside, the drying device being fixed

  interchangeable on the body of the desiccator and so that the

  central outlet vertex communicates with a body air channel

of the desiccator.

  A drying device of this type * is described in relation to an air dryer in the German patent application DE-OS 30 Il 721, where the drying device and the air dryer together form a closed member by screwing The desiccant is contained in a container in the form of a cartridge, which takes the form of a hollow cylindrical part having a bottom open in the center and forming the outlet opening, the cylindrical part being closed at the opposite end by a perforated disc

  and additionally containing a perforated disc similar to a certain

  outlet opening The desiccant is between the two perforated discs This cartridge is pressed, in the body of the air dryer and by means of a spring, against an air filter

  located in your region of the exit opening The body of the desicca-

  tor surrounds the cylindrical wall of the cartridge with an interval, which communicates at the end, at the level of the central opening and through the air filter with an air channel p Zévu in the body of the desiccator Air to be dehydrated therefore passes through the filter

  air and then the interval between the outer casing and the car-

  touch, to finally go back in the opposite direction in the body of the

  through the desiccant and the outlet opening at the end

  lower part The outer casing is securely but removably connected to the body of the desiccator. A desiccator for compressed air brakes, of commercial vehicles for example, must be subjected to an annual maintenance approximately

  during which the desiccant must be replaced With the desicca-

  tor described above, it is necessary for this to first remove the outer casingof the body of the desiccator All the parts located in this outer casing, such as the air filter, the cartridge and the spring compressing the cartridge, are then present under separate parts form The cartridge is replaced by a new cartridge placed in the outer envelope, which must be reassembled

  Then the assembly and disassembly work for such an operation

  maintenance-is considerable with the known device Similarly, the air dryer, as a complete device, is relatively

  complicated, expensive and expensive It has many parts.

  The invention aims to create a drying device

  tion of the type indicated at the beginning but which facilitates maintenance and which simplifies and makes more economical the overall construction of a

  air dryer equipped with such a device.

  According to the invention, such a drying device is essentially characterized in that it is produced as a member assembled in the form of a disposable box which is replaced

  in its entirety during the maintenance of the desiccator -

  The assembly and disassembly work is thus

  reduced since it now suffices to detach a complete organ-from-

  body of the desiccator and replace it with a new body, without this work giving rise to parts which are detached in the interior of the desiccator and which must be replaced which requires time during reassembly. operations

  maintenance are thus considerably facilitated Another advantage

  tage is that the element provided on the desiccation device for its attachment to the body of the desiccator, element which is susceptible

  wear and which consists of an internal or external thread

  is replaced at the same time, which also facilitates work

  assembly and disassembly values In addition, an air dryer

  pe of such a desiccation device is simpler and more economical

  because the number of pieces is lower and because the

construction is simplified.

  According to a particularly advantageous embodiment

  tagous, the disposable boot forming the pre-drying device

  feels a tube preferably directed inwardly ex-

  v end by which the boot is fixed to the body of the desiccator, tubing which surrounds the central outlet opening and contains a

  internal thread through which the boot can be screwed onto a tube

  lure with external thread of the desiccator body.

  The boot can thus be screwed quickly and without problems on the desiccator and be unscrewed from it as easily, when it has to be replaced. The reverse arrangement of the connecting elements, that is to say the arrangement of the internal thread in a tube. of the desiccator body and the external thread on

  disposable boot tubing has the same advantages.

  It is also advantageous to provide a provision

  safety device, described in detail in what follows, between the body of the desiccator and the disposable boot Such a device makes it possible, by simple means, to block the boot in rotation after its screwing

  on the desiccator body and produce at the same time> practical-

  without additional cost of the device, the pressure relief being able to reign inside the desiccator and the boot during

  unscrewing a security screw that is part of this device.

  According to another advantageous embodiment, the

  disposable boot in the shape of a closed pot of all sides and whose

  vertex located at the fixing end is covered by an end cover This embodiment, the other details of which are also described below, is very economical The possible loss of power, due to the absence of the prc Qndensat-on provided in the apparatus described in the prior art, is low in the lower and middle ranges of service temperatures and is perfectly acceptable Yet another embodiment, described

  thereafter, allows precondensation and avoids any loss of

  while retaining the indicated advantages of the solution according to

the invention.

  Several embodiments of the invention are shown without limitation in the accompanying drawings and will be described below. In the drawings, Figure 1 is a schematic axial section of a drying device for air dryers, according to a first exemplary embodiment of the invention Figure 2 is a schematic end view of the desiccation device, taken along arrow II in Figure 1 Figure 3 is a section along the line III-III of Figure 1;

  Figure 4 is a more detailed representation-

  and on a larger scale of detail IV in FIG. 1 L FIG. 5 is a side view taken in the direction of the arrow V in FIG. 4 FIGS. 6, 7 and 8 are schematic axial sections of desiccation devices according to a 2 nd, a 3 rd and a 4 th exemplary embodiment of the invention; Figure 9 is a bottom view of the desiccant device of Figure 8; and

  FIG. 10 is a detail of the drying device

cation of figure 8.

  Figures 1 to 5 show a device for

  desiccation 10 for air dryers which are intended in part

  Particularly for the compressed air brakes of vehicles, which are provided with an air tank and supplied by a compressor. These can be air dryers with one container or two containers. Figure 4 shows part of a desiccator and especially a

  portion of its body fl and of the air channel 12 contained therein.

  The desiccation device 10 is made as an organ assembled under the form of a disposable boot which is replaced

  in its entirety during the maintenance operation of the desiccator.

  The device 10 comprises a pot 13, made of thin sheet metal for example, in which a desiccant 14 is directly charged, which is preferably capable of being regenerated The cylindrical side wall of the pot 13 and its bottom represented at the top in FIG. 1 are closed Its end, represented at the bottom, by which the desiccation device 10 can be fixed to the body ll of the desiccator, is closed by a cover 15, made of sheet metal for example, which is mechanically fixed in a solid and watertight manner over the whole around its edge in pot 13, with the insertion of a

  sealing ring 16 The connection is made in the example shown

:

  felt by crimping the bottom edge of the pot 13 around the neck

  vercle It is also possible to fix the cover by gluing, = welding or in another way The cover 15 carries in the middle a tube 17 directed towards the interior of the pot and in a single piece with the cover The passage formed by this tubing forms the central outlet opening 18 for dry air The tubing 17 has

  furthermore an internal thread 19, corresponding to an external thread

  laughing 21 on a tube 20 of the desiccator The device for

  siccation 10 can be installed and screwed quickly and easily

  on the desiccator Its assembly and disassembly are therefore

  quent fast and simple On its fixing face directed towards the

  body II of the desiccator, the cover 15 carries a status ring

  chewiness, in the form of a flat seal 22 for example, which is applied against a corresponding sealing surface 23 of the body 11 The cover 15 also has inlet openings 24 which are distributed around the tube 17 and through which air can enter in the direction of the arrows 25 into the drying device 10, that is to say in the opposite direction to the air outlet in the direction of the arrow 26 through the outlet opening 18 of the

tubing 17.

  The pot 13 contains a central tube 27 which extends

  substantially over the entire length of the pot and has a side wall

  rale closed The end of the tube shown at the bottom in FIG. 1 joins the cover 15 with the interposition of a joint 28 At this

  -right, the tube 27 surrounds the internal tubing 17 The extremity op-

  laid tube 27 joins the bottom 29 of the pot, in which case its side wall has holes, or is located a short distance from the bottom 29 In either case, this end of the tube 27 communicates near the bottom 29 with an air chamber 30 formed at this location The pot 13 contains therein at least one transverse disc 31 centered on the tube 27, provided with air passage orifices 32 and in contact with the desiccant 14 The disc 31 is profiled in star shape for example This zone can additionally include a filtering disc 33 for post-filtration If the latter is sufficient

  rigid, it can at the same time form the transverse support disc 31.

  The opposite portion of the pot 13, on the side of the lid, contains a similar disc 34 centered on the tube 27 and provided with air passage holes 35 The disc 34 also has a

  particular profiling in that it has an annular groove

  slide 36 open at the bottom and forming an annular upward protuberance in the representation of FIG. 1 The disc 34 carries a filtering disc 37 for the pre-filtration The desiccant 14 in the pot 13 is compressed by an elastic element which is constituted here by a compression spring 38 between the support disc 34 and the cover 15 and penetrating at one end into the groove

  annular 36, which ensures the centering of the spring.

  After it has been screwed onto the body 11 of the desiccator, the desiccation device 10 is blocked at its fixing position on the body II by a safety device 39, the details of which emerge in particular in FIGS. 4 and 5 Near the end of the body 11 having the sealing surface 23 against which the drying device 10 is fixed, the safety device 39 has a safety screw 42 which can be screwed into a threaded hole 40 in the side wall 41 of the body 11 , as well as a bracket 43 fixed by this screw The branch 44 of this bracket is tightened under the head of the safety screw 42, while its branch 45 enters a hole 46 in the wall 41, so as to prevent the rotation of the bracket 43 The branch 44, clamped by and adapted in its shape to that of the screw head> ends at the top, in the representations

  Figures 4 and 5, by a nose 47 directed towards the underside of the neck

circle 15.

  On the side of the cover 15 directed towards the body 11 of the desiccator, the desiccation device 10 has a series of tongues 49 carried by a ring 48 and uniformly distributed angularly on a circle concentric with the axis of the device, see also Figure 2 The tongues 49 can be formed, for example, by cutting and folding portions of the material of the ring 48 The tongues 49 are oriented approximately radially and constitute locking protrusions to prevent rotation of the desiccation device 10 in cooperation with the nose 47 of

  the bracket 43 when the screw 42 is tightened.

  The safety screw 42 has the additional function, when it is loose, which must precede the disassembly of the box 10, to relax the interior of this box by putting the outlet opening 18 into communication through the air channel 12 of the body 11 with the external atmosphere Consequently, during the defection of the safety, the desiccator is at the same time relaxed for the case where it is under pressure. For this additional function, the screw of its rete 4 2 protrudes, by so N interior end opposite the head, in the air channel 12 and has an axial bore 51 which opens at this interior end and opens out by a piercing

  transverse 52 in the lateral surface of the screw 42 at low dis-

  tance of its head When the screw 42 is loose and when a ring

  seal 53 normally pressed against the body 11 of the drawing

  screwed away from the body 11, the transverse bore 52

communicates with the atmosphere.

  During operation, the box 10 having been screwed onto the body 11 of the desiccator, moist air enters through the inlet orifices 24 of the cover 15 in the direction of the arrows

  inside the pot 13 Before the air enters the dehydra-

  while 14, it passes through the orifices 35 of the disc 34 and through the filtering disc 37 which, as an inlet filter, removes the air from

  droplets of oil, carbon and other foreign matter.

  Then, the air passes through the desiccant 14 from bottom to top, in the representation of FIG. 1, before passing through the orifices 32

  of the disc 31 and by the filtering disc 33 of post-filtration and rete-

  bare of desiccant The air then enters the upper end of the tube 27, crosses it and returns through the outlet opening 18

  below in the body 11 of the desiccator, to enter more precisely-

  in the air channel 12 The air inlet in the pot 13 is sealed externally by the flat seal 22 and radially

  inside by the described threaded connection of the pipes 17 and 20.

  Instead of providing an internal thread 19 in the pipe 17, it is also possible, as already indicated, to provide an external thread on the pipe 17 and an internal thread

in the tubing 20 of the body 11.

  Pa its realization ccmmeun assembled body t completes to throw after a certain period of use (1 year for example), the r

  desiccation device or boot 10 brings significant advantages.

  It considerably facilitates maintenance operations, i.e. assembly and disassembly, since it is now sufficient to replace

  boot 10 in its entirety, which can be done quickly and easily-

  Furthermore, the boot 10 is in itself of simple construction. As a result, and since the air dryer is adapted accordingly,

  the whole device becomes cheaper Another advantage

  tage is that the part likely to wear out of the connection between the box and the desiccator, in this case the internal thread 19, is replaced at the same time as the boot 10 during maintenance The conformation of the box 10 according to the invention allows a simpler and more economical construction of the whole desiccator, notably by reducing the dimensions and the number of different

  parts that make it up and by simplifying construction.

  Although pre-condensation of the air to be dehydrated is not possible

  sible with the example of realization which has just been described from the dis-

  drying positive 10, this absence of precondensation does not

  has practically no loss of power in the lower ranges

  lower and average service temperatures.

  The second exemplary embodiment, represented in FIG. 6, uses references similar to those of the first example but increased by 100, which will be used below without

new explanations.

  The desiccation device or boot 110 of FIG. 6 comprises an interior pot 113 which contains the desiccant, like the pot-13 of the first example The pot 113 is closed at both ends by at least one disc 131, 134 which has orifices for air passage 132, 135 and further carries a filtering disc 133, 137 The disposable boot 110 of this example additionally comprises an outer envelope 161 which is roughly hat-shaped and

  which surrounds the pot 113 externally with at least a small inter-

  valle 160 The opening of this outer envelope, located

  fixing end directed downwards in the representation of FIG. 6, is closed by the lid 115 as is the case in the first example according to FIGS. 1 to 5 for the pot 13 On the side of the lid 115, the pot 113 has a wall 162 which is impermeable to

  air and has a central opening 163 which receives, with inter-

  position of the seal 128, the tube 117 of the cover 115 The dehy-

  dratant is compressed inside the pot 113 by means of a buffer or an elastic element, formed in this example by a compression spring 138 which, unlike the first example, acts in the example of the Figure 6 on the upper disc 132, where this spring penetrates at one end into an annular groove 136, while its other end is supported on the upper wall 164 of the outer casing 161 It is important in this case that the lower wall 162 pot is waterproof During service the air to dry enters, as in the first example, through the orifices

  124 of the cover 115, as indicated by the arrow 125.

  Then, the air penetrates on the other hand, with a view to precondensation,

  in the interval 160 between the pot 113 and the outer envelope 161.

  As indicated by the arrows 165, the air rises through the interval 166 in the air chamber 130 provided in the hamt and from there penetrates through the orifices 132 and the filter disc 133 in the desiccant After having passed through the desiccant, ' what it does from top to bottom in the example of FIG. 6, the air passes through the orifices 135 and the filtering disc 137 then through the outlet opening 118 to enter

  the direction of the arrow 126 inside the body of the desiccator.

  The air is cooled during its rise in the direction of the arrows 165 to

  across the interval 160, which produces a peruet precondensation-

  both the separation, before crossing the desiccant, of

  density and impurities, in the form of oil or scale by

  example This example retains the realization of the desiccant dispsoitive

  cation sots form a disposable box and at the same time it keeps the

  simple construction and the other advantages of the first example of a

  and it provides the added benefit that any loss of

power is avoided.

  Figure 7 shows a third example of a

  reading which uses, again to avoid unused repetitions, references increased by 200 for the elements which correspond

  to those of the first or second example.

  The example shown in Figure 7 does not differ-

  cie that little of the second example shown in Figure 6 The inner pot 213 is in this case closed like a cap, with removal of the upper disc 231, and it is only provided with

  bottom of a lower disc 234 which has through holes.

  of air 235, the pot being closed under this disc by a perforated wall 262 with a central opening 263 The wall 262 and the disc 234 maintain between them a filtering disc 237 for post-filtration The upper wall 270 of the pot 213, which is d in one piece with its

  cylindrical wall, in this case fulfills the function of the upper disc

  laughing 131 of Figure 6 It contains for this purpose 'orifices, air passage 271 The central area of the wall 270 is covered with a filter disc 233 forming an inlet filter This filter is covered at the top by a part 272 in the form of a dome, defining an air chamber 230, of the upper wall 264 of the outer casing 261 The profiling of the upper wall 264 forms, in addition

  lady 272, channels, not visible in FIG. 7, which make

  provide the air chamber 230 with the interval 260. The desiccant 214 of this example is again compressed in the inner pot 213,

  either directly through the outer casing 261, or pax of the elements -

  As in the example shown in the

  FIG. 7, the wall 262 of the inner pot rests on the cover 23.

  this lower wall, and with it the disc 234 disposed in the inner pot 213, are pushed upwards by the cover 215, owing to the fact that the drying device of this example is assembled with precompression of the desiccant 214 This precompression is collected directly by the desiccant The filtering disc 23 is completed by an external filtering ring 273 which is located at about the same height between the cover 215 and the wall 262 of the internal container. Figures 8 to 10 show a fourth exemplary embodiment, 'the elements of which correspond to those of the previous examples bear similar but increased references

  300, for the reason already stated.

  The fourth example corresponds in its basic construction to the second and the third example However, the interval 360 between the outer casing 361 which is roughly hat-shaped and the inner pot 313 of this fourth example is gradually filled close completely by a cylindrical filtering casing 337 I which acts as an inlet filter This filter is therefore arranged laterally in this case, instead of on the end shown at the top in the drawings The filtering casing 337 can be formed, by example, as shown, of a filter layer folded in half and then curved in the form of a cylinder with the incorporation of a cylindrical inner piece 380 of stiffening or support between the two layers The cylindrical piece 380 is made of perforated sheet metal and is supported on the cover 315 by its end - shown below

  in figure 8 In the same way as in the second and the third

  sith example, the inner pot 313 is closed at the top in the representation of FIG. 8 by a disc 331 provided with air passage orifices 332 and pressed by a compression spring 338 against the desiccant 314 The inner pot 313 is closed below by an impermeable wall 362 which is fixed in this case in the form of a separate part to the external envelope 361, for example by means of a sheet 381 curved into a cylinder, provided with a marginal rib and crimped by its edge on the pot 313 As in the third example in Figure 7, the j oi N t 128 provided in the

  second example (Figure 6) is deleted in this fourth example.

  The seal is obtained here by a particular conformation of the bottom wall 362 of the inner pot. Above this wall is, as in the previous examples, a filtering disc.

  lower 333 for post-filtration.

  This fourth example further comprises a safety device 339 which is simplified compared to that of the first example. The safety screw 342, instead of attacking a part of the disposable boot by a bracket or another intermediate element, penetrates directly by its free end opposite the screw head in a cooperating element for blocking the boot in rotation. The threaded hole 340 is therefore obliquely oriented towards the

  high, so that the safety screw 342 is directed, by its ex-

  free end, obliquely from bottom to top towards cover 315 of

the disposable boot.

  The ring 348 located under the cover 315 has tabs directed downwards, or, as shown, openings 350 into which the free end of the screw 34 s can penetrate to block the rotation of the disposable boot

  forming the desiccation device.

Claims (17)

  1 Desiccation device for air dryers intended for compressed air installations powered by a compressor and having a compressed air reservoir, in particular for vehicle air brakes, comprising a container 1 loaded with a dehydration product or desiccant, which can preferably be regenerated, and provided at one end with a central outlet opening for dry air, the air to be dehydrated penetrating through orifices in the container and passing through the desiccant   inside, the drying device being attached interchangeably   lo geable on the body of the desiccator and so that the opening   central outlet communicates with an air channel of the body of the desic-   I * cator, characterized in that it is produced as an assembled member IW in the form of a disposable boot (10; 110) which is replaced in its   all during maintenance of the desiccator.   | I 15 2 Device according to claim 1, characterized in   what the disposable boot forming the pre-drying device   It feels a tube (17-; 117) preferably directed towards the interior   I laughing at the end by which the boot is fixed to the body (11) of the desiccator, tubing which surrounds the central outlet opening (18; 118) and contains an internal thread (19; 119) by which the boot can be screwed on a tubing with an external thread (20) of the body (11) of the desiccator.   3 Device according to claim 2, characterized in that the tubing (17; 117) is located on an end cover i 25 (15; 115; 215) of the box having inlet openings (2; 124) for an air inlet (arrows 25; 125) in the opposite direction to the I | air outlet (arrow 26; 126).   js LI Device according to claim 3, characterized in that the cover (15; 115; 215) carries a sealing ring   -30 (22), for example in the form of a flat seal, on its fixing face.   Device according to any one of claims 1 to 4, characterized in that it is combined with a release device (39) for locking its fixing position on the body Goi (11) of an air dryer.   I i. i r i 6 Device according to claim 5, characterized in   what the safety device (39; 339) includes, near the   half of the body (11) of the desiccator on which the device is fixed   desiccant, a safety screw (42, 342) which cooperates mechanically   nically, directly (figure 10) or indirectly (figure 4)> with   a corresponding element (49; 350) for blocking the rotation of the device. positive desiccation.   7 Device according to claim 6, characterized in that the safety screw (42) projects into an air channel (12)   body (11) of the desiccator - by its inner end and pre-   feels an axial bore (51) which opens at the inner end of the screw and opens at the opposite end of the screw by a transverse bore (52) in the lateral surface of the screw, this transverse piercing being placed communication with the atmosphere when the   safety screw (42) is tightened and when a seal (53), normal-   pressed by the screw against the body (11) of the desiccator,   moves away from the body (11) of the desiccator.   8 Device according to any one of the claims.   tions l to 7, characterized in that its end by which it   is attached to the body (11) of the desiccator has blocking elements   rotating cage, in particular tongues (49) projecting axially 1-Lie or openings (350), which are formed on or in a ring (48; 348) fixed to the desiccation device, preferably   by being distributed uniformly around the tubing (17).   9 Device according to any one of the claims.   tions 6 to 8, characterized in that the safety screw (42) is combined with a safety piece (43) which can be tightened by the screw, preferably so that the piece cannot turn 2 , and that   has a nose (47) which cooperates with one of the locking elements (49)   rotating cage to prevent rotation of the drying device   cation. Device according to claim 8, characterized in that the safety screw (342) penetrates directly through its free inner end into an opening (350) of the ring (348), thereby preventing the rotation of the drying device relative to to the body (11) of the desiccator.   11 Device according to any one of the claims.   tones ià 10, characterized in that it comprises a pet (13) whose La   wall is closed on all sides and the opening provided at i '-   the fixing end is covered with an end cover (15).   12 Device according to claim 11, characterized in that the pot (13) contains a central tube (27), the end of which   cover side (15) surrounds the tubing (17) and whose excrémi-é.   opposite communicates with an air chaimbre (30) in the region of bottom (29) of the pot.   13 Device according to claim il or 12, charac-   terized in that the desiccant (14) is loaded directly into the   pot (13) and is compressed at one end of the pot by a trans-   support versal (34) which is placed on the central tube (27) and is provided with air passage orifices (35), as well as by an elastic element (38), in particular by a compression spring, who   acts on this disc (34) and is pressed on the pot (I 3).   14 Device according to any one of the claims   tions 1, to 13, characterized in that the pot (13) has at least one transverse support disc (31) provided with through holes   air (32) near its bottom (29).   Device according to claim 14, characterized in that the pot (13) contains a filtering disc (33, 37) disposed 3 ur the central tube (27) in the region of its bottom (29) and / or in the   region of its opposite end -   16 Device according to any of the revandicz-   tions 13 to 15, characterized in that the support disc is closed by the filter disc.   17 Device according to any of the claims   tions 11 to 16, characterized in that the pot (13) is mechanically connected securely and tightly to the lid (15), around the entire periphery of the edge thereof, in particular by gluing, welding or crimping.   18 Device according to any one of the claims.   tions 1 to 10, characterized in that it comprises an inner pot (113; 213) containing the desiccant (214) and closed at both ends by transverse support discs (131, 134; 270, 234) provided with - 15 of air passage openings (132, 135; 271, 235), as well as an outer envelope (161; 261) roughly in the form of a hat which surrounds the pot with the formation of a gap (160; 260) between them and whose opening provided at the fixing end is covered by the cover (115; 215). 19 Device according to claim 18, characterized in that the wall of the pot (162; 262) adjacent to the cover (115; 215) is impermeable and has a central opening (163; 263)   into which the tubing (117) enters.   20 Device according to claim 18 or 19, charac-   t = rised in that the internal pot (113; 213) and / or the external envelope (161, 164; 261, 272) contains a filtering disc (133,   137; 233, 237, 273) in the region of one and / or the other extreme moth.   21 Device according to any one of the claims.   tions 18 to 20, characterized in that the desiccant (214) is compressed in the inner pot (113; 213) by an elastic element (138), in the form of a compression spring or a buffer for example, which acts on a support disc (131; 234, 262) and is   pressed on the outer envelope (161, 164; 261, 215).   22 Device according to any one of the claims.   tions 18 to 20, characterized in that the desiccant (214) in the   inner pot (213) is compressed directly by the outer casing superior (261, 215).   23 Device according to any one of the claims.   tions 18 to 22, characterized in that the interval (360) between the   outer cover (361) which is roughly hat-shaped and the inner pot (313) contains a filter ring, preferably a cylindrical filter cover which fills the gap '(360) almost completely, acting as a filter entry, and in that a filtering disc (333) of post-filtration is provided at the neighboring end of the cover (315).   24 Device according to claim 23, characterized in that the filter envelope (337) is held in place by an internal cylindrical stiffening or support part (380) which is provided with bores and is formed in particular of a t 8 the perforated.   Device according to any one of the claims   tions 19 to 24, characterized in that the inner pot comprises, on the side of the cover, an impermeable wall (362) which is closed by a separate piece and which is fixed, for example by crimping, to the outer casing (361 ). g