GB2126124A

GB2126124A - A drying device for air dryers

Info

Publication number: GB2126124A
Application number: GB08323538A
Authority: GB
Inventors: Helmut Scholz; Ingolf Grauel; Gunther Kulke; Andreas Reppich; Klaus Ronnefarth; Klaus Tschammerholl; Joachim Delfs
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1982-09-03
Filing date: 1983-09-02
Publication date: 1984-03-21
Also published as: SE8304745D0; GB8323538D0; GB2126124B; SE454410B; FR2532557A1; FR2532557B1; SE8304745L; DE3232742C2; DE8224847U1; DE3232742A1

Abstract

A drying device for air dryers of compressed-air brake systems for commercial vehicles comprises a complete, canister-like component and disposable part which may be replaced in its entirety as a structural unit. It has a pot (13) into which the drying agent (14) is directly introduced and which is closed at the mounting end by means of an end cover (15). The end cover incorporates a central outlet opening (18) having an internal screw-thread (19) by means of which the complete pot is screwable onto a screw-threaded connection of the air drier housing. The air enters through inlet openings (24) in the end cover (15), passes through a prefilter (37), the drying agent (14), an after-filter (33) and then flows through a central tube (27) from one end of the pot to the other and to the outlet opening (18). In a preferred embodiment a safety screw (42) having a pressure relief passage (51, 52) secures a safety tab (43) which prevents the drying device from being unscrewed before the safety screw is released. <IMAGE>

Description

SPECIFICATION A drying device for air driers The invention relates to a drying device for air driers intended for compressed air systems, such as compressed air brake systems of vehicles.

A drying device for this purpose is described in connection with an air drier in German Patent Specification (Offenlegungsschrift) No.

30 11 725, in which the drying device forms a closed, screwed on operational part together with the air dryer. The drying agent is contained in a housing in the form of a cartridge constituting a cylindrical member which has a base which is open in the centre thereof to form an outlet opening and which is closed at the opposite end by means of a perforated disc and which also has a similar perforated disc spaced from the outlet opening. The drying agent is located between the two perforated discs. This cartridge is precompressed in the housing of the air drier against an air filter in the region of the outlet opening by means of a spring. The housing surrounds the cylindrical wall of the cartridge to form a gap which, in the end region thereof, communicates with a passage in the housing of the air drier by way of the air filter on a level with the central outlet opening.Hence, the air to be dried passes through the air filter and then through the space between the outer housing and the cartridge and, in the opposite direction of flow thereto, finally passes through the drying agent back into the housing of the air drier by way of the outlet opening at the bottom end. The outer housing is rigidly, but releasably, connected to the housing of the air drier. An air drier for compressed-air brake systems of, for example, commercial vehicles should be subjected to maintenance, in which the drying agent has to be changed, at approximately yearly intervals. For this purpose, in the described air drier, the outer housing first has to be released from the housing of the air drier. All the parts located within the outer housing then result as individual parts, namely the air filter, the cartridge and the spring which precompresses the latter.During maintenance, the cartridge is replaced by a fresh one which is fitted into the outer housing which then has to be mounted again. This assembly and disassembly involves a considerable amount of expenditure in the known design. Furthermore, in view of this design, the air drier as a complete unit is relatively complicated and expensive. It has a large number of individual parts.

An object of the invention is to provide a drying device for air driers which facilitates maintenance work and simplifies and reduces the cost of the overall construction of an air drier equipped with a drying device.

Accordingly, the present invention provides a drying device for air driers intended for compressed-air systems which are chargeable by a compressor and are provided with a compressed-air reservoir, said device having a housing into which a drying agent is introduced and which has at one end a central outlet opening for the egress of the air which is to be dried and which can be guided through openings in the housing into and through the housing, the drying device being constructed as a complete, canisterlike component and disposable part which is interchangeable and securable to the air drier housing such that the central outlet opening can communicate with an air passage in the air drier housing, so that the device can be changed in its entirety as a structural unit during maintenance of the air drier.

The expenditure on assembly and disassembly is reduced, since only one complete component has to be detached from the housing of the air drier and replaced by a fresh one without these operations resulting in individual parts in the interior as loose elements which again have to be fitted with increased expenditure during assembly.

The maintenance work is thereby substantially facilitated. Furthermore, it is advantageous that the canister-like or box-like component and its fastening part which is subjected to wear and which serves for the securing thereof, namely the internal screw thread or, in kinematic reversal, the external screw thread, and thereby jointly exchanged, thus also facilitating assembly and disassembly work. Furthermore, an air drier equipped with a drying device is simplified as a complete unit and is rendered less expensive, since the number of individual parts is reduced and the construction of the unit is simplified.

Preferably, that end of the complete component by which the complete component is mountable on the air drier housing has a nipple member which extends into the interior of the housing and which includes the central outlet opening and an internal screw thread by means of which the complete component is screwable onto an externally screw threaded connection of the air drier housing.

The design is particularly advantageous. By means of a central internal screw thread of this kind, the canister-like drying device can be screwed rapidly and without difficulty onto the housing of the air drier and can be released therefrom for purposes of interchange. The kinematic reversal, that is to say, the outer screw thread on the canister-like complete components.

provides similar advantages.

A safety device by which the position of the complete component on the air drier housing is secured is also advantageous. On the one hand, it is ensured that a complete, screwed-in component is protected against turning by simple means, and, on the other hand, means for venting upon loosening of a safety screw can at the same time be integrated in this anti-turning means virtually without additional expense, so that, in addition, pressure in the complete canister-like component can be relieved.

The housing of the complete component can be in the form of a pot whose wall is closed on all sides and whose mouth, located at the mounting end, is closed by means of the end cover.

This is particularly advantageous. Such design leads to low expense. Any loss of performance in the lower and middle ranges of operating temperature resulting from the absence of precondensation compared with the prior art to which reference has been made, is only slight and is quite acceptable.

In other embodiments, the housing of the complete component has an inner pot into which the drying agent is introduced and which is closed at both ends by means of end plates provided with air ports and approximately hat-shaped outer casing which surrounds the pot with a space therebetween and whose opening located at the mounting end is closed by means of the end cover.

These designs enable pre-condensation, so that there is no loss of performance despite the retention of the other advantages set forth initially.

The invention is further described by way of example, with reference to the accompanying drawings in which:~ Flg. 1 is a diagrammatic, axial longitudinal section through a drying device for an air drier in accordance with a first embodiment of the present invention, Fig. 2 is a diagrammatic view of the drying device, viewed in the direction of arrow II of Fig. 1, Fig. 3 is a fragmentary section taken along the line Ill-Ill of Fig. 1, Fig. 4 is a section of a detail IV of Fig. 1, to a larger scale and showing a detail of an adjacent part of the air drier to which the device is fitted, Flg. 5 is an end elevation viewed in the direction of the arrow V of Fig. 4, Figs. 6, 7 and 8 are each a diagrammatic axial longitudinal section through a drying device in accordance with a second, third and fourth embodiment respectively, Flg. 9 is an inverted plan view of the drying device of Fig. 8, and Fig. 10 is a section through a detail of the drying device of Fig. 8, to a larger scale and also showing a detail of the air drier.

Figs. 1 to 5 show a drying device 10 for air driers which are intended particularly for compressed-air brake systems of commercial vehicles which are provided with a compressed-air reservoir chargeable by a compressor. The air drier may be a single-container air drier or a twincontainer air drier. Fig. 4 shows a portion of an air drier, that is, a portion of the air drier housing 1 1 and of the air passage 1 2 incorporated therein.

The drying device 10 is in the form of a complete, box-like component and disposable part or canister which can be exchanged as a complete assembly when servicing the air drier.

It has a housing in the form of a pot 13 which is made from, for example, thin sheet metal and into which is directly introduced a, preferably regenerable, drying agent or desiccant 14. The wall of the pot 13 is closed in its cylindrical region and in the region of its base. That end of the pot 13 which is located at the bottom in Fig. 1, and by which the drying device 10 is mountable on the end face of the air drier housing 1 1 (mounting end), is closed by means of an end cover 15 which is made from, for example, sheet metal and whose edge is sealingly and mechanically rigidly connected to the pot 13 all around with an interposed sealing ring 16. In the illustrated embodiment, the connection is effected by flanging the rim of the pot 13. In another embodiment (not illustrated), the connection is effected by glueing, soldering, welding or the like.

The centre of the end cover 15 carries an integral nipple member 1 7 having a central outlet opening 18 for the air and an internal screw-thread 19 incorporated therein. As shown in Fig. 4, a screwthreaded connection piece 20 having a corresponding external screw-thread 21 is associated with the internal screw thread 19. In this manner, the internal screw thread 19 of the drying device 10 can be mounted and screwed onto the air drier in a simple manner, and consequently can be mounted and disassembled in a rapid and umcomplicated manner. The mounting surface of the end cover 1 5 directed towards the air drier housing 11 carries an annular seal, such as a flat seal 22, which comes into abutment against an associated sealing surface 23.Air can enter the drying device 10 in the direction of the arrows 25 (Fig. 1) through inlet openings 24 distributed around the nipple member 17 in the end cover 15, namely in the opposite direction to the outflow of air which is effected in the direction of the arrow 26 (Fig. 1) through the outlet opening 18 in the nipple member 17.

The interior of the pot 13 contains a continuous, central tube 27 having a closed wall.

That end of the tube 27 which is at the bottom in Fig. 1 extends to the end cover 15 where, by way of an interposed seal 28, the tube 27 overlaps or is telescoped over the nipple member 1 8 which thus extends into the tube 27. The opposite end of the tube 27 wither extends to the base 29 of the pot and has openings in the wall in this region, or the end of the tube terminates at a small distance from the base 29 of the pot. In both cases, this end of the tube 27 communicates with an air chamber 30 in the region of the base 29 of the pot where the pot 13 contains at least one end disc 31 which is centered on the tube 27 and which is provided with air ports 32 and is in contact with the drying agent 14. The end disc 31 has, for example, a somewhat stellate profile.

Furthermore, a filter plate 33 serving as an afterfilter can be located in this region and, if it has adequate rigidity, could also form the end disc 31 itself.

An end plate 34 which is provided with air ports 35, and which is centred on the tube 27, is also located at the opposite end in the pot 13 containing the end cover 15. This end plate 34 also has a special profile and is provided with an annular groove 36 which, in Fig. 1, is directed upwardly, the end plate 34 likewise carrying a filter plate 37 which acts as a prefilter. A spring element, in the form of a compression spring 38 in the present instance, is located between the end plate 34 and the bottom end cover 15. One end of the compression spring 38 engages, and is centred in, the annular groove 36, the drying agent 14 being precompressed in the pot 13 by the said spring 38.

Moreover, a safety device 39 is provided by which the canister-like drying device 10 screwed onto the air drier housing 11 is secured in position and whose details are shown particularly in Figs.

3, 4 and 5. The safety device 39 has a safety screw 42 which is screwable into a screwthreaded bore 40 in the wall 41 of the air drier housing 11 in the vicinity of the end thereof which bears the sealing surface 23 and which serves for mounting the drying device 10. The safety device 39 also has an angled safety tab 43 which is securable by means of the safety screw 42. One limb 44 of the safety tab 43 is clamped by means of the head of the safety screw 42, while the limb 45 at right angles to the aforesaid limb engages a recess 46 within the wall 41 in a form-locking manner to prevent pivoting of the safety tab 43.

Referring to Figs. 4 and 5, the limb 44 adapted to the screw head merges upwardly into a thinner projecting lug 47 which is directed towards the underside of the end cover 15.

That side of the end cover 1 5 of the canisterlike drying device 10 which is directed towards the air drier housing 11 has tongues 49 which are mounted on a ring 48 and which are disposed at equal circumferential angular distances apart along a circular line and are formed by, for example, cutting in windows and bending over from the material of the ring 48. The individual tongues 49 extend substantially radially, as can be seen from each of Figs. 1 to 5. They form safety projections of the canister-like drying device 10 which, when the safety screw 42 is tightened.

cooperate with the projecting lug 47 of the safety tab 43 to prevent the device 10 from turning relative to the air drier housing 11.

Furthermore, the safety screw 42 serves to vent the outlet opening 18 of the drying device 10 to the atmosphere by way of the air passage 12 in the air drier housing 11 upon loosening of the screw 42, which has to precede the disassembly of the box-like drying device 10, so that, if the drying device 10 is under pressure, it is simultaneously vented when releasing the safety means.

The threaded end of the safety screw 42 remote from the head thereof extends into the air passage 12. The safety screw 42 has an axial bore 51 which is open towards this threaded end and which terminates at a relatively short distance from the head of the screw and, in this region, communicates with a transverse bore 52 which is open towards the circumferential surface of the safety screw 42. The transverse bore 52 is ventable to the atmosphere upon loosening the safety screw 42 and upon the lifting of a seal 53 which is pressed against the air drier housing 11 by means of the safety screw 42.

During operation, when the box-like drying device 10 has been screwed onto the air drier housing 11, moist air flows through the inlet openings 24 in the end cover 15 in the direction of the arrow 25 into the interior of the pot 13. Before the air enters the drying agent 14, is passes through the air ports 35 in the end plate 34 and the filter plate 37 which is located in this region and which acts as a prefilter to separate oil droplets, oil carbon and other contamination. The air then flows through the drying agent 14 from top to bottom as viewed in Fig. 1 and passes through the air ports 32 in the end plate 31 and through the filter plate 33 which is located in this region and which has the function of an after-filter which holds back the level of the drying agent.The air then flows into the top end (as viewed in Fig. 1) of the tube 27 and back into the air drier housing 11 by way of the tube and its bottom outlet opening 18, namely into the air passage 12. The air flowing into the pot 13 is sealed externally by way of the flat seal 22 and internally by way of the screw-threaded connection 2 and the screw coupling which has been described.

Instead of the nipple part 17 having the internal screw thread 19 in the region of a drying device 10, a kinematically reversed construction can be chosen in a modified design in which the drying device 10 is secured by means of an external screw thread on the drying device 10 instead of the internal screw thread 19.

The described design of the drying device 10 as a complete component and disposable part has substantial advantages. It substantially facilitates maintenance work, that is to say, assembly and disassembly, since only one complete element has to be exchanged for this purpose, and this can be effected rapidly and in a simple manner.

Furthermore, the drying device 10 is of simple construction. This construction and the matching design of the air drier reduces the cost of the entire unit. A further advantage is that an element which is subjected to wear during exchange and which interconnects the drying device and the air drier, the internal screw thread 19 in the present instance, is exchanged together with the drying device 1 0. The design of the drying device 1 0 simplifies the complete air drier and reduces its cost with respect to the number of individual parts and the construction of the individual components. Although it is not possible to achieve pre-condensation in the air to be dried, in the described embodiment of the drying device 10, this results in virtually no loss of performance in the lower and middle ranges of operating temperature.

Reference numerals increased by 100 are used for the parts of the second embodiment illustrated in Fig. 6 which correspond to those of the first.

embodiment, so that reference is made to the description of the first embodiment in order to avoid unnecessary repetition.

Referring to Fig. 6, the housing of the drying device 110 contains an inner pot 113 into which the drying agent is introduced in the same manner as the drying agent 14 is introduced into the pot 13 in the first embodiment. Each of the two ends of the pot 113 is closed by at least one end plate 131, 134, and each end plate is provided with air ports 132 or 135 and also carries a filter plate 133 or 137. Furthermore, a component part of the housing is an approximately hat-like external casing 161 which surrounds the pot 113 externally with at least a small space 160 therebetween and whose opening located at the downwardly directed mounting end as viewed in Fig. 6 is closed by means of the end cover 11 5, as in the case in the first embodiment of Figs. 1 to 5 with respect to the pot 13.The wall 1 62 of the pot 113 which is adjacent to the end cover 11 5 is impermeable to air and contains a central opening 163 which is engaged by the nipple member 117 on the end cover 115 with the seal 128 interposed therebetween. The drying agent is precompressed in the internal pot 113 by means of the spring element in the form of the compression spring 138 which, in contrast to the first embodiment, acts upon the upper end plate 131, as viewed in Fig. 6. One end of the spring 138 engages an annular groove 136 in the top end plate, and its other end is supported on the upper wall 1 64 of the outer casing 1 61. It is important that the bottom wall 1 62 of the pot should be impermeable and leakproof. During operation, the air to be dried flows in through the inlet openings 124 in the end cover 11 5 in the direction of the arrow 125, in the same manner as in the first embodiment.However, the air then flows into the space 160 between the pot 113 and the outer casing 161 for the purpose of precondensation. The air flows upwardly in the space 160 in the direction of the arrows 165 into the air chamber 130 and then into the drying agent through the air ports 132 and the filter plate 133. After passing through the drying agent from the top to the bottom as viewed in Fig. 6, the air flows through the air ports 135 and the filter plate 137 into the outlet opening 11 8 from where it again flows into the interior of the air drier housing in the direction of the arrow 126. The air is cooled as it flows upwardly through the space 1 60 in the direction of the arrow 1 65, and precondensation takes place. Water of condenation and dirt, such as oil, oil carbon and other impurities can then separate.In this embodiment, the design as a disposable part, the simple construction and the other advantages of the first embodiment are retained and there is the further advantage that there are no losses with respect to performance.

For the purpose mentioned previously, reference numerals increased by 200 are used for the parts of the third embodiment of Fig. 7 which correspond to those of the first or second embodiment.

The third embodiment of Fig. 7 differs only slightly from the second embodiment of Fig. 6. In the present instance, the inner pot 213 is closed in a hat-like manner with the omission of the top end plate 131 and only its bottom end is provided with the bottom end plate 234 with incorporates air ports 235. The pot 213 is closed at a distance below the end plate 234 by means of an imperforate pot wall 262 which, however, defines a central opening 263. A filter plate 237 for afterfiltering is located between the pot wall 262 and the end plate 234. In the present instance, the upper wall 270 of the post 213 is integral with its cylindrical portion and fulfils the task of the upper end plate 131 of Fig. 6. It includes air ports 271. A filter plate 233 for pre-filtering is located above this region.The upper wall 264 of the outer casing 261 is profiled to form a domed part 272 containing an air chamber 230 which communicates with the space 260 by way of passages (not visible) which are determined by the profiling. The filter plate 233 is located within the air chamber 230.

In the present embodiment, the drying agent 214 in the inner pot 213 is precompressed either directly by means of the outer casing 261 or by parts thereof. Since the lower pot wall 262 rests on the end cover 215 in the illustrated embodiment, the lower pot wall 262 and the end plate 234 are urged upwardly within the inner pot 213 in Fig. 7, whereby the drying agent 214 is precompressed. In this instance, the drying device is assembled under prestress. The prestressing force is absorbed directly by the drying agent.

Furthermore, an outer filter ring 273 located between the end cover 215 and the wall 262 of the pot is disposed at approximately the same height as the filter plate 237 to supplement the latter.

For the purpose previously mentioned, reference numerals increased by 300 are used for the parts of the fourth embodiment of Figs. 8 to 10 which correspond to those of the previous embodiments.

The basic construction of the fourth embodiment corresponds to that of the second and third embodiments. In the fourth embodiment, of course, the space 360 between the approximately hat-shaped outer casing 361 and the inner pot 313 is provided with a filter ring in the form of a cylindrical filter casing 337 which substantially completely fills the space 360 and which acts as a prefilter. Hence, the latter in the present case is located in the circumferential region instead of being located at the top end in the drawings. By way of example, the filter casing 337 is folded to form a double layer and is bent to form a cylinder. It is held in its position by means of an inner support part 380 between the two layers. The support part 380 comprises a cylindrically bent perforated plate whose bottom end as viewed in Fig. 8 is seated on the end cover 315. In the same manner as in the second and third embodiments, the top end, as viewed in Fig.

8, of the inner pot 313 is closed by means of an end plate 331 which is provided with air ports 332 and by which the drying agent 314 is precompressed by means of a compression spring 338. The bottom end of the inner port 313 is closed by means of the impermeable pot wall 362 which, in the present instance, is secured to the outer casing 361 as a separate part by means of for example, a cylindrically bent plate 381 which is cylindrically flanged to the pot 313. As in the third embodiment of Fig. 7, the seal 128 provided in the second embodiment of Fig. 6 is also omitted in the fourth embodiment of Fig. 8. The sealing action is ensured by the special configuration of the bottom wall 362 of the pot. in the same manner as in the previous embodiments, the bottom filter plate 333 acting as an after-filter is located above the lower wall 362 of the pot.

The safety device 339 (Fig. 10) of the fourth embodiment is simplified compared with that of the first embodiment. The safety screw 342 does not indirectly engage, by way of a safety tab, an associated element for preventing turning of the drying device, but engages it directly by means of its free end remote from the screw head. For this purpose, the screw-threaded bore 340 extends obliquely upwardly, so that the free end of the screwed-in safety screw 342 is directly obliquely upwardly towards the end cover 315 of the drying device.

As shown in Figs. 9 and 10, a ring 348 extending below the end cover 315 has tongues or reception openings 350 extending within the plane of the ring, so that the free end of the screwed-in safety screw 342 can engage one of these reception openings 350 to prevent turning.

Claims

1. A drying device for air driers intended for compressed-air systems which are chargeable by a compressor and are provided with a compressed-air reservoir, said device having a housing into which a drying agent is introduced and which has at one end a central outlet opening for the egress of the air which is to be dried and which can be guided through openings in the housing into and through the housing, the drying device being constructed as a complete, canisterlike component and disposable part which is interchangeable and securable to the air drier housing such that the central outlet opening can communicate with an air passage in the air drier housing, so that the device can be changed in its entirety as a structural unit during maintenance of the air drier.

2. A drying device as claimed in claim 1, in which that end of the complete component by which the complete component is mountable on the air drier housing has a nipple member which extends into the interior of the housing and which includes the central outlet opening and an internal screw thread by means of which the complete component is screwable onto an externally screw threaded connection of the air drier housing.

3. A drying device as claimed in claim 2, in which the nipple member is seated on an end cover of the complete component, which end cover incorporates inlet openings for the inlet of air in a direction opposite to the direction of flow of the outlet air.

4. A drying device as claimed in claim 3, in which the mounting surface of the end cover carries an annular seal.

5. A drying device as claimed in any of claims 1 to 4, having a safety device by which the position of the complete component on the air drier housing is secured.

6. A drying device provided with a safety device by which the position of the drying device on a housing is secured.

7. A drying device as claimed in claim 5 of 6, in which the safety device is mountable onto the complete component in the vicinity of the mounting end of the air drier housing and includes a screw-in safety screw which cooperates in a form locking manner directly or indirectly with an associated element for preventing turning of the complete component on the air drier housing.

8. A drying device as claimed in claim 7, in which the screw-in end of the safety screw extends into an air passage of the air drier housing, and the safety screw has an axial bore which is open towards the screw-in end and which, in the region of the other end of the safety screw, communicates with a transverse bore which is open towards the circumferential surface of the safety screw and which is ventable to the atmosphere upon loosening of the safety screw and the lifting of a seal which is pressed against the air drier housing by the safety screw.

9. A drying device as claimed in any of claims 1 to 8, in which that end of the complete component by which the latter is mountable onto the air drier housing has elements for preventing turning which elements are spaced at equal circumferential angular distances apart.

10. A drying device as claimed in claim 9, in which said elements for preventing turning are axially projecting tongues or reception openings which are formed on or in a ring secured to the complete component.

11. A drying device as claimed in claim 9 or 10 when appendant to claim 7 or 8, in which the safety screw has an associated safety tab which is clampable by means of the safety screw and which is securable against pivoting and which has a lug projection which, for the purpose of preventing turning, cooperates with one of the elements for preventing turning.

12. A drying device as claimed in claim 9 or 10, when appendant to claim 7 or 8 in which the free end of the safety screw engages directly into a reception opening in the ring so as to prevent turning.

13. A drying device as claimed in any of claims 3 to 12, in which the housing of the complete component is in the form of a pot whose wall is closed on all sides and whose mouth, located at the mounting end, is closed by means of the end cover.

14. A drying device as claimed in claim 13, in which the pot contains a central tube whose end facing the end cover extends up to the nipple member engaging therein and whose oppositely located end in the region of the base of the pot at the end thereof communicates with an air chamber at this location.

15. A drying device as claimed in claim 13 or 14, in which the drying agent is introduced directly into the pot and is compressed at one end of the pot by means of at least one end plate which is provided with air ports and which is mounted on the central tube, and by means of a spring element which acts upon the end plate and is supported on the pot.

16. A drying device as claimed in any of claims 13 to 15, in which the pot has, in the vicinity of its base, at least one end plate provided with air ports.

17. A drying device as claimed in claim 16, in which the pot contains, in the region of the base of the pot and/or the opposite end, a filter plate which is seated on the central tube.

18. A drying device as claimed in any of claims 15 to 17, in which the respective end plate is formed by the filter plate.

19. A drying device as claimed in any of claims 13 to 18, in which the pot is sealingly and mechanically rigidly connected, e.g. glued, soldered, welded or flanged, to the end cover around the edge thereof.

20. A drying device as claimed in any of claims 1 to 12, in which the housing of the complete component has an inner pot into which the drying agent is introduced and which is closed at both ends by means of end plates provided with air ports and an approximately hat-shaped outer casing which surrounds the pot with a space therebetween and whose opening located at the mounting end is closed by means of the end cover.

21. A drying device as claimed in claims 2 and 20, in which the pot wall adjacent to the end cover is impermeable and includes a central opening into which the nipple member engages.

22. A drying device as claimed in claim 20 or 21, in which the inner pot and/or the outer casing contains a filter plate in the region of one and/oi the other end.

23. A drying device as claimed in any of claims 20 to 22, in which the drying agent in the inner pot is precompressed by means of a spring element, such as a compression spring or a buffer element, which acts upon an end plate and which is supported on the outer casing.

24. A drying device as claimed in any of claims 20 to 22, in which the drying agent in the inner pot is precompressed directly by means of the outer casing.

25. A drying device as claimed in any of claims 20 to 24, in which the space between the approximately hat-shaped outer casing and the inner pot contains a filter ring which substantially fills said space and which serves as a prefilter, and in which a filter plate acting as an after-filter is disposed in the region of the end adjacent to the end cover.

26. A drying device as claimed in claim 25, in which the filter casing is held in position by means of an inner, cylindrical support part which is provided with openings.

27. A drying device as claimed in any of claims 21 to 26, in which the impermeable wall of the pot is in the form of a separate part and is secured to the outer casing.

28. A drying device constructed substantially as herein described with reference to and as illustrated in the accompanying drawings.