DE10253113A1 - Dryers, especially dryers - Google Patents

Abstract

Industrial clothes dryers have a relatively complex drum (11). The drum (11) is sealed with wear-sensitive and the drive of the drum (11) braking slip ring seals against a housing (10). The known drums (11) also have a relatively low concentricity, which additionally loads the seals. DOLLAR A The laundry dryer according to the invention has a self-supporting, inherently stable drum (11). For this purpose, a drum cage (22) of the drum (11) is self-supporting. This gives the drum (11) a greater running accuracy and it can coat panel parts (24) easier on the drum cage (22) fasten, at least partially clamping, causing the sheath sheet metal parts (24) can change without jamming in length. Furthermore, it is provided to form seals (40) between the drum (11) and the stationary housing (10) without contact. Such seals (40) are not subject to any significant wear. The non-contact seals (40) are also possible because the drum cage (22) is inherently stable and self-supporting, whereby the drum (11) has a better running accuracy than is the case with known tumble dryers.

Description

The invention relates to a dryer, especially a tumble dryer, according to the generic term of claim 1, 5 and 13, respectively.

Dryers, especially dryers for the commercial area (laundries etc.), have one rotating drivable drum. The drum points to opposite Ends or opposite Ending rings on. With the races the drum rests on wheels. At least one impeller is drivable, so over here the Drum frictionally engaged in a rotational movement about its longitudinal central axis is displaceable. The longitudinal central axis The drum simultaneously forms its axis of rotation.

In the known dryers, and in particular, tumble dryers, The races are made of a metal strand formed into a circle educated. Such races have only over a moderate running accuracy. Seals the drum to a surrounding, this fixed Housing must therefore quite complicated as so-called slip ring seals are formed. These slip ring seals wear out over time and complicate turning the drum.

Another disadvantage of known dryer is that a serving to form the drum cylindrical Jacket plate is bolted to the races. That does not make it difficult only the production of known drums; especially a repair more expensive if the jacket plate or parts of the same exchanged Need to become. In addition let the glands of the jacket plate with the races unavoidable changes in length the jacket plate or its parts during heating and cooling of the Dryer only limited. The result is thermally induced Deformations, in particular bulges, of the jacket sheet.

On this basis, the invention is based the object of a dryer, in particular tumble dryer, to create a simple and easy to assemble and removable drum has. At the same time, the dryer should wear his.

A dryer to solve this Task has the features of claim 1. The compound of the invention the raceways leads through struts to a stable drum cage, the one precise Concentricity of the drum allows. The drum cage forms a static-carrying part of the drum, which is a reliable and precise Storage of the jacket plate of the drum allows, causing the jacket plate even have no or no significant bearing properties got to. As a result, in particular one of several jacket sheet metal parts formed jacket sheet can be easily connected to the drum cage, without requiring a connection of the shell sheet metal parts with each other becomes.

The preferably with the races welded Aspirations are according to one preferred embodiment of the device with a profiled cross-section Provided. Preferably, the struts are box-like or hollow profile-like it is sufficient, the hollow profile is not completely closed, but for example open unilaterally. This design the aspiration carries in particular in connection with the welding of the same with the races to form a stable, self-supporting drum cage.

Another dryer to solve the initially mentioned object, which is also a development of the dryer described above has the features of claim 5. Accordingly, the shrouds are made of several formed individual jacket sheet metal parts, which are connected by clamping with the drum cage are. The thus from the drum cage and a plurality of directly not related shell sheet metal parts formed drum leaves simply put together. Just as needed, individual Sheath sheet metal parts are replaced. It's not like at known driers many screws for connecting the jacket plate or the shell sheet metal parts with the races required. By the clamping connection of at least some edge regions of the shell sheet metal parts with the drum cage can use the number of screws to connect the shroud the drum cage be significantly reduced. The at least partially clamping connection the cladding panel parts with the drum cage allows relative movements of the cladding panel parts to the drum cage to, for example, by a temperature-induced expansion the shell sheet metal parts this or their corresponding edges due the frictionally and / or non-positively connected by the clamping connection itself relative to the drum cage, especially the pursuit of the same, can move.

According to a preferred embodiment of Device are only the transverse edges or adjoining edge areas the cladding sheet parts clamped to the struts, and although preferably by terminal strips. The attachment of the transverse edges the sheath sheet metal parts is to pay special attention to so that it is sufficient, only the transverse edges of the shell sheet metal parts clamped to the bars of the drum cage to fix. The long edges the shell sheet metal parts can in conventional Be screwed to the races, where it is sufficient only relatively few To use screws.

The terminal strips are preferably simultaneously formed as projecting ribs inside the drum. As a result, the terminal strips have a double function, that is, they are No additional Components for the terminal strips required.

The clamping of the transverse edge regions of the shell sheet metal parts on the drum cage takes place preferably between the terminal strips and the struts. For this purpose, the struts according to a preferred embodiment of the invention in the plane of the transverse edge regions of the shroud parts lying protruding clamping legs. By counter screwing the terminal strips against the struts the terminal strips or Andruckschenkel the same, pressed in the direction of the clamping legs of the struts. In this case, transverse edge regions of the jacket sheet metal parts are clamped between the Andruckschenkeln the terminal strips and clamping legs of the struts. In this way, an easy to manufacture, but a reliable and durable frictional and non-positive connection of the transverse edges or transverse edge regions of the shell sheet metal parts with the drum shell comes about. In particular, the transverse edge portions of the cladding sheet metal parts can move between the clamping legs and the Andruckschenkeln and thereby compensate for changes in length of the cladding sheet metal parts during warming up and cooling of the drum. Any constraints of the shell sheet metal parts, in particular bulges thereof, are practically excluded.

Another dryer to solve the initially mentioned object, which is also a preferred Development of the dryer described above can act, has the features of claim 13. Accordingly, at least one frontal opening the drum opposite the fixed housing by at least one non-contact Seal sealed. This non-contact Seal is as good as not subject to any wear and slows down the Do not drum off against the direction of rotation. This will be the force to drive the drum opposite known dryer with rubbing slip ring seals reduced.

The non-contact sealing of the drum against the casing takes place in the region of each race on an opening having Front side of the drum. Especially for drums with a stable drum cage has the respective race over a high running accuracy, whereby with small gap widths one reliable and always non-contact Seal is feasible.

To the running accuracy of the races to increase, are the outer peripheral surface and the outside lying end face of at least that race, the formation a non-contact seals serves, edited. The preferably machining (turning, Grinding or the like) takes place after the races through the struts are connected by particular welding. Than it will be at the same time during processing a possible distortion of the races eliminated by welding. In particular, with the invention statically supporting, stable Training of the drum cage and the machining of the races allows a very high running accuracy also big drums achieve the non-contact Seals to the housing even at relatively low Gap widths allows.

The non-contact sealing of the drum against the stationary housing takes place in the region of the respective opening at one or both opposite End faces of the drum by annular end-side areas opposite the races a closely spaced adjacent end wall of the housing. It can the existing sealing gap can be reduced by at least one gap-reducing ring-like coating, in particular sealing coating. This is designed so that it is the respective end face of the race while the rotation of the drum is not affected, and only one sealing gap to the relevant end face of the race leaves, the relatively narrow is.

A preferred embodiment the device according to the invention will be explained in more detail with reference to the drawing. In this show:

1 a schematic, perspective view of a clothes dryer,

2 a perspective view of a drum of the clothes dryer,

3 an end view of the drum of 2 .

4 a central cross section through the drum of 2 and 3 in the area of two opposite ribs,

5 an enlarged partial cross section through the dryer in the region of a seal between the drum and a housing, and

6 an enlarged cross section through the drum in the region of a rib.

The dryer shown here acts it is a tumble dryer, and a continuous tumble dryer, for in particular commercial purposes such as laundries.

The tumble dryer has a stationary, preferably cuboid housing 10 , in which there is a rotating drivable cylindrical drum 11 located. The drum 11 is about a longitudinal central axis 12 rotatable drivable. As a result, the longitudinal central axis forms 12 the drum 11 at the same time the axis of rotation of the same. The drum 11 has cylindrical races in the areas of their opposite ends 13 on. With the races 13 the drum is resting 11 on wheels 14 , In the embodiment shown are four wheels 14 provided, with each race 13 two wheels 14 assigned ( 1 ). Two wheels 14 and an impeller 14 per race 13 , Are by a common drive, in the embodiment shown an electric motor 15 , rotating drivable. The two driven wheels 14 act as friction wheels for Reibradantrieb the drum 11 on the outer circumference of the races 13 , The wheels 14 and the drive, in particular the electric motor 15 , are inside the Ge häuses 10 under the drum 11 stored, on a frame, not shown, of the tumble dryer.

The cylindrical drum 11 has a cylindrical drum wall and two opposite, circular end faces. In the continuous tumble dryer shown here is in each end of the drum 11 a circular opening, namely a loading opening 16 and a discharge opening 17 intended. Both the loading opening 16 as well as the discharge opening 17 are from one at the respective end face of the drum 11 arranged circular ring wall 18 surround. The housing 10 has in each of the opposite end walls 19 over one with the loading opening 16 and the discharge opening 17 in the drum 11 corresponding, circular housing opening 20 respectively. 21 , Every housing opening 20 and 21 is by a lid 44 closable. As a result, during the drying process, the housing 10 to the outside liquid-tight and temperature-tight lockable.

In accordance with the invention special way is the drum 11 educated. The drum 11 is composed of a drum cage 22 and a cylindrical jacket plate 23 , where the jacket sheet 23 is formed in several parts, namely from several shell sheet metal parts 24 composed. In the embodiment shown ( 2 and 3 ) are four equally sized sheath sheet metal parts 24 provided, each extending over about a quarter of the circumference of the shroud 23 extend.

The drum cage 22 is formed stable according to the invention. This training is such that the drum cage 22 forms a statically self-supporting unit. The drum cage 22 holds thereby the shell sheet metal parts 24 together, and without the cladding panels 24 are interconnected. The drum cage 22 is composed of two races 13 and for connecting the same serving struts 25 , In the illustrated embodiment, the races are 13 through four equal aspirations 25 connected evenly to the circumference of the cylindrical drum 11 are distributed, so have about quarter circle distances from each other. The opposite ends of the drum 11 associated races 13 are the same design, preferably have the same dimensions. The aspiration 25 are with the races 13 welded. This gets the drum cage 22 the inventively provided in itself stable and self-supporting property.

The races 13 show at the drum shown here 11 an L-shaped angle profile. A longer thigh 26 this angle profile is circular. The outside of the long thigh 26 forms a cylindrical tread 27 of the race 13 , with which the races 13 on the wheels 14 rest. A lying in the plane of the respective end face short leg 28 every race 13 extends in the direction of the longitudinal central axis 12 , It forms the circumferential short leg 28 the loading opening 16 or the discharge opening 17 surrounding circular ring wall 18 at the respective end face of the drum 11 , An outwardly facing side of the circulating short leg 28 of the respective race 13 formed Kreisringwandung 18 the drum 11 forms a circular sealing surface 29 , The races 13 are preferably after the completion of the drum cage 22 processed. Preferably, the treads 27 and the sealing surfaces 29 the races 13 machined by milling, turning, grinding or the like. These operations are preferably carried out during a continuous rotation of the finished drum cage 22 , As a result, the treads run 27 exactly concentric to the longitudinal central axis 12 and thus also to the axis of rotation of the drum 11 , Likewise, the machining of the sealing surfaces 29 exactly perpendicular to the longitudinal central axis 12 , causing the races 13 the drum 11 give a very precise concentricity.

The aspiration 25 are designed as elongated profiles. These may be hollow sections or box sections. In the embodiment shown ( 6 ) is the cross section of each strut 25 formed approximately Ω-like. Accordingly, each has the same trained struts 25 over a central U-shaped area, with the U to the outside of the drum 11 is open. At free outer ends of the parallel legs of the U-shaped central region close outwardly projecting clamping leg 30 on. The two clamping legs 30 extend in opposite directions to the outside, so are directed away from each other. The clamping legs 30 are to the outer diameter of the shroud 23 the drum 11 adjusted by the inside of the drum 11 facing surfaces of the clamping legs 30 approximately on the outer diameter of the jacket plate 23 lie.

With opposite, slightly bevelled end portions are the struts 25 with the respective race 13 preferably connected by welding ( 5 ). This connection takes place in the area of the horizontal, long leg 26 every race 13 , at the inside of the drum 11 pointing inside of the long thighs 26 , In the illustrated embodiment, the clamping legs 30 in the area where the end areas of the struts 25 the long thighs 26 overlap, removed ( 5 ). As a result of welding of struts 25 with the races 13 and the profiled formation of the cross section of the struts 25 form the struts 25 with the races 13 the inherently stable, statically supporting drum cage 22 ,

The shell sheet metal parts 24 are dimensioned so that between mutually facing transverse edges 31 adjacent shell sheet metal parts 24 a narrow space arises through which the U-shaped Middle part of the respective strut 25 protrudes. In this case, overlap at the transverse edges 31 adjacent shell sheet metal parts 24 adjacent transverse edge regions of the shell sheet metal parts 24 partially, preferably for the most part, the clamping legs 30 the respective strut 25 ( 6 ). On the clamping legs 30 are those of the transverse edges 31 outgoing transverse edge regions in each case two adjacent shell sheet metal parts 24 fastened by clamping over its entire length, namely clamped, by a respective terminal strip, which at the same time a rib 32 inside the drum 11 forms. Every rib 32 is thus at the same time a terminal block. Each of the same ribs 32 has a hat-shaped cross-section. This is formed by a narrow bridge 33 , from the both sides obliquely directed legs 34 out. The thigh 34 are oppositely inclined and run thereby starting from the bridge 33 diverging towards the clamping legs 30 the respective strut 25 , The to the clamping legs 30 pointing ends of the thighs 34 are inward to the U-shaped middle area of the respective strut 25 angled and parallel to the clamping legs 30 , These angled ends of the legs 34 form Andruckschenkel 35 attached to the clamping legs 30 opposite insides of the transverse edges 31 adjacent shell sheet metal parts 24 outgoing transverse edge areas of the same ( 6 ). At the frontal areas of the struts 25 are the end portions of the thighs 34 Angled outwards to form corner angles 46 ( 2 . 4 and 6 ).

Ribs 32 are indirect with the struts 25 screwed. These are in the interior of the hat-like profiled rib 32 preferably at least in the radial direction of the drum 11 elastic coupling links 36 intended. The coupling links 36 are on the jetty 37 the U-shaped middle section of the respective strut 25 arranged and here with the jetty 37 the strut 25 connected. At the top carries each coupling link 36 A mother 38 , In the mother 38 is one in the 6 not shown screw through a through hole 39 in the web 36 the rib 32 screwed. Preferably, per strut 25 or rib 32 two to four screws and associated coupling links 36 provided, evenly to the length of the strut 25 and the rib 32 are distributed ( 4 ). By appropriate tightening the respective screw is the Koppeglied 36 in the radial direction of the drum 11 stretched elastically, so that an upper side of the respective coupling member 36 with the mother 38 to the plant under the footbridge 33 the rib 32 arrives. The stretched coupling links 36 tend to be the rib 32 against the respective strut 25 to press, ie in the radial direction of the drum 11 seen to the outside. These are the from the transverse edges 31 the shell sheet metal parts 24 outgoing transverse edge portions thereof continuously between the clamping legs 30 the strut 25 and the pressure legs 35 the rib 32 clamped ( 6 ), by the bias of the coupling links 36 the Andruckschenkel 35 against the transverse edge regions of the shell sheet metal parts 24 and thus against the clamping legs 30 the strut 25 suppressed. It comes thereby a surface, frictional and non-positive attachment of the transverse edges 31 the shell sheet metal parts 24 outgoing transverse edge regions thereof at the respective strut 25 of the drum cage 22 conditions. This type of connection of the transverse edge regions of the shell sheet metal parts 24 with the struts 25 allows almost non-constraining length changes of the sheath sheet metal parts 24 to, by expansions of heated shell sheet metal parts 24 a further pushing in the transverse edge regions of the shell sheet metal parts 24 in the gap between the Andruckschenkel 35 , the rib 32 and the clamping leg 30 the strut 25 allow. Conversely, a shortening of the jacket plate part 24 when cooling the same to the fact that the transverse edges 31 the shell sheet metal parts 24 can withdraw in the said gap. Overstress and especially bulging of the shell sheet metal parts 24 as a result of thermally induced changes in length of the same are thereby effectively avoided.

In the circumferential direction of the drum 11 extending longitudinal edges of the shell sheet metal parts 24 are with the races 13 and the long thighs 26 the same, screwed ( 2 ). Because of the clamping attachment of the transverse edge portions of the shell sheet metal parts 24 on the struts 25 running continuously over the entire transverse edges 31 the shell sheet metal parts 24 extend, and thus the shell sheet metal parts 24 over the entire length of its transverse edges 31 on the drum cage 22 are clamped fastened, need the longitudinal edges of the shell sheet metal parts 24 only with a few screws on the races 13 to be attached. In this case, the holes in areas of the longitudinal edges of the Mantelblechteile 24 be formed slot-like, so that the screws thermally induced changes in length of the shroud parts 24 do not hinder.

Each mostly open end of the drum 11 is opposite the respective end wall 19 of the housing 10 sealed, and that according to the invention by means of a non-contact seal 40 , In the 5 the seal 40 is in the region of the loading opening 16 partially shown the tumble dryer. With a same seal 40 is the discharge opening 17 in the opposite end of the drum 11 opposite the housing 10 sealed. The seal 40 is formed between an outer ring portion of the annular sealing surface 29 on the outside of the short thigh 28 every race 13 and one the housing opening 20 surrounding annular area of the end wall 19 on the loading side of the housing 10 , This is in ge showed embodiment of the end face of the drum 11 facing inside of the Sitrnwandung 19 of the housing 11 a the housing opening 20 surrounding annular sealing coating 41 assigned. The sealing coating 41 is with the inside of the end wall 19 of the housing 10 firmly connected, preferably glued. The sealant is formed 41 made of a soft material that is particularly heat resistant. It may be a felt material, a rubber, a plastic or the like. The sealing coating 41 partially overlaps the sealing surface 29 of the short thigh 28 of the respective race 13 ( 5 ). It arises between the sealing surface 29 and the facing to this sealing surface 42 of the sealing coating 41 a narrow annular gap 45 , the non-contact, labyrinthine sealing of the relevant end face of the drum 11 opposite the housing 10 brought about so that no significant exchange of air between the inside of the drum 11 and the outside thereof, in particular a lower part 43 of the housing 10 , can take place. In addition, an air exchange with the environment is prevented by the lid 44 , The lid 44 closes when in-service continuous washing machine located on the loading side housing opening 20 and also a central part of the loading opening 16 the drum 11 but with an annular gap 45 no contact with the rotating drum 11 can take place.

The invention is not only suitable for the above-described continuous tumble dryer with a loading opening 16 on one end face of the drum 11 at a discharge opening 17 on the opposite end of the drum 11 ; rather, for other types of dryers, especially those that only at one end of the drum 11 have an opening which also serves as a loading and unloading. In this case, a seal needs 40 only at that end of the drum 11 to be present, which also serves to load and unload the laundry. The opposite, closed end of the drum 11 then needs no seal 40 , Incidentally, however, the drum is designed as described above, in particular with a self-supporting drum cage 22 and shell sheet metal parts 24 provided throughout the entire length of the transverse edges 31 or transverse edge regions clamped to the struts 25 of the drum cage 22 are attached.

10

casing

11

drum

12

Longitudinal central axis

13

race

14

Wheel

15

electric motor

16

loading opening

17

unloading

18

Kreisringwandung

19

end wall

20

housing opening

21

housing opening

22

drum cage

23

shell plate

24

Coat sheet metal part

25

strut

26

longer leg

27

tread

28

short leg

29

sealing surface

30

clamping leg

31

transverse edge

32

rib

33

web

34

leg

35

pressure-applying

36

coupling member

37

web

38

mother

39

Through Hole

40

poetry

41

sealing covering

42

sealing surface

43

lower part

44

cover

45

annular gap

46

corner angle

Claims (20)

Dryers, in particular tumble dryers, with a rotating drivable drum ( 11 ), which is a cylindrical jacket ( 23 ) and circular races ( 13 ), wherein the drum ( 11 ) with the races ( 13 ) on wheels ( 14 ) and at least one impeller ( 14 ), characterized in that the races ( 13 ) by striving ( 25 ) are connected such that the races ( 13 ) with the struts ( 25 ) a stable drum cage ( 22 ) form. Dryer according to claim 1, characterized in that the races ( 13 ) by several preferably evenly on the circumference of the drum ( 11 ) and parallel to a longitudinal central axis ( 12 ) of the drum ( 11 ) running struts ( 25 ), the struts ( 25 ) preferably firmly with the races ( 13 ) are connected. Dryer according to claim 1 or 2, characterized in that the struts ( 25 ) are profiled in cross section, in particular box or hollow profile-like design. Dryer according to one of the preceding claims, characterized in that the races ( 13 ) at the end faces of the drum cage ( 22 ) are arranged or end faces of the drum cage ( 22 ), and the aspirations ( 25 ) for connecting the races ( 13 ) between the end faces of the drum cage ( 22 ) to find oneself. Dryer, in particular tumble dryer, with a rotatably drivable, cylindrical drum ( 11 ), which is a jacket sheet ( 23 ) and races ( 13 ), in particular according to one of the preceding claims, characterized in that the races ( 13 ) by striving ( 25 ) to a drum cage ( 22 ), and the jacket plate ( 23 ) of several individual jacket sheet metal parts ( 24 ) is formed which at least partially clamped with the drum cage ( 22 ) are connectable. Dryer according to one of the preceding claims, characterized in that transverse edges ( 31 ) or from the transverse edges ( 31 ) outgoing edge regions of the shell sheet metal parts ( 24 ) on the struts ( 25 ) are clamped fastened. Dryer according to one of the preceding claims, characterized in that the transverse edges ( 31 ), in particular adjacent areas, the shell panel parts ( 24 ) by clamping strips preferably non-positively and / or frictionally engaged on the struts ( 25 ) are clamped. Dryer according to one of the preceding claims, characterized in that in the region of each strut ( 25 ) and each terminal strip opposite transverse edges ( 31 ) or adjoining border areas of adjacent shell sheet metal parts ( 24 ) continuously, preferably over the substantially entire length of the transverse edges ( 31 ) or adjoining edge regions, can be fastened in a clamping manner. Dryer according to one of the preceding claims, characterized in that the transverse edges ( 31 ) or adjoining edge regions of the shell sheet metal parts ( 24 ) between on opposite sides of the struts ( 25 ) projecting clamping legs ( 30 ) of aspiration ( 25 ) and approximately parallel to the clamping legs ( 30 ) extending Andruckschenkeln ( 35 ) of the terminal strips are clamped. Dryer according to one of the preceding claims, characterized in that in each case a terminal strip with a strut ( 25 ) releasably connected, in particular screwed, wherein the distance of the terminal block, in particular the Andruckschenkel ( 35 ) to the clamping legs ( 30 ) of the respective strut ( 25 ), preferably elastically or resiliently can be changed for the continuous clamping of the transverse edges ( 31 ) or adjoining edge regions of the shell sheet metal parts ( 24 ) on the drum cage ( 22 ). Dryer according to one of the preceding claims, characterized in that the shell sheet metal parts ( 24 ) with their circular arc-shaped longitudinal edges on the races ( 13 ) are additionally fastened, preferably by screws. Dryer according to one of the preceding claims, characterized in that the clamping strips as inside the drum ( 11 ) projecting ribs ( 32 ) are formed. Dryer, in particular tumble dryer, with a rotatably drivable, cylindrical drum ( 11 ), which is a jacket sheet ( 23 ) and races ( 13 ) and at least one opening in an end face, and with a drum ( 11 ) surrounding fixed housing ( 10 ), in particular according to one of the preceding claims, characterized in that at least the end face of the drum having the opening by at least one non-contact seal ( 40 ) opposite the housing ( 10 ) is sealed. Dryer according to one of the preceding claims, characterized in that the or each seal ( 40 ) in the region of at least one raceway ( 13 ) is arranged. Dryer according to one of the preceding claims, characterized in that the respective seal ( 40 ) between a free, outer end face of at least one raceway ( 13 ) and an opposite end wall ( 19 ) of the housing ( 10 ) is arranged. Dryer according to one of the preceding claims, characterized in that the seal in a narrow gap (annular gap 45 ) between the end face of the respective race ( 13 ) and the adjacent end wall ( 19 ) of the housing ( 10 ) is arranged. Dryer according to one of the preceding claims, characterized in that at least the or each of the end face of the respective race ( 13 ) facing inside of the end wall ( 19 ) of the housing ( 10 ) at least partially with a gap (annular gap 45 ) narrowing or one-sided limiting sealing coating ( 41 ) is provided. Dryer after one of the previous ones Claims, characterized in that at least one race ( 13 ) in particular on the outer peripheral surface (tread 27 ) and the end wall ( 19 ) of the housing ( 10 ) facing outer end face (sealing surface 29 ), edited. Dryer according to one of the preceding claims, characterized in that the outer end face of at least one raceway ( 13 ) is processed such that the end face (sealing surface 29 ) as exactly as possible perpendicular to the longitudinal central axis ( 12 ) of the drum ( 11 ) corresponding axis of rotation runs. Dryer according to one of the preceding claims, characterized in that the tread ( 27 ) at least one race ( 13 ) is machined so that they are as exactly as possible concentric to the axis of rotation or longitudinal central axis ( 12 ) of the drum ( 11 ) runs.