Patent Publication Number: US-7210990-B2

Title: Treatment apparatus for treating workpieces or groups of workpieces

Description:
RELATED APPLICATION 
   The present disclosure refers to the subject matter that was disclosed in German patent application No. 10 2004 015 5.6 of 30 Mar. 2004. The entire description of this earlier application is incorporated by reference in the present description (“incorporation by reference”). 
   FIELD OF THE DISCLOSURE 
   The present invention relates to a treatment apparatus for treating workpieces or groups of workpieces that are conveyed from an inlet to an outlet of the treatment apparatus. 
   BACKGROUND 
   Such an apparatus is known, for example, from DE 44 42 152 A1. 
   In the treatment apparatus known from DE 44 42 152 A1, the parts to be treated are fed to so-called “virtual chambers” and in these virtual chambers are conveyed through processing treatments. This treatment apparatus comprises a plurality of circular bases disposed with spacing one above the other, which are enclosed by a wall cylinder and between which there is in each case a system of blades disposed at uniform angular intervals. The blade systems rotate jointly relative to the bases, wherein each base has a window and the windows of successive bases in the direction of passage of the workpieces are disposed offset relative to one another counter to the direction of rotation of the blade systems so that the workpieces, which are fed in each case into a “virtual chamber” delimited by two blades, complete in each case a partial circuit along the bases to the window of the relevant base and, there, then fall onto the base situated underneath, where they then complete the next partial circuit. The chambers in this apparatus are described as “virtual” because in the course of conveying the workpiece they continuously exchange their real bottom and top walls. 
   The treatment apparatus known from DE 44 42 152 A1 is provided for the processing treatment of small workpieces, which are not damaged by the drop through a base window from one level to the next level of the treatment apparatus. 
   Particularly in the case of heavier workpieces having a surface that should not be damaged, an uncontrolled drop from one level to another level of the treatment apparatus does however present a considerable risk. 
   SUMMARY OF THE INVENTION 
   The underlying object of the present invention is to provide a treatment apparatus for treating workpieces or groups of workpieces that are conveyed from an inlet to an outlet of the treatment apparatus, wherein the treatment apparatus comprises a plurality of treatment levels and in the treatment apparatus the workpieces to be treated are passed from level to level in a safe and controlled manner. 
   According to the invention this object is achieved by means of a treatment apparatus, which comprises a housing and receiving chambers, which rotate relative to the housing, for receiving the workpieces or groups of workpieces, wherein the receiving chambers are disposed in at least two different chamber levels and an outlet opening in the housing is associated with a first chamber level, through which the workpieces or groups of workpieces travel first, and an inlet opening is associated with a second chamber level, through which the workpieces or groups of workpieces travel after the first chamber level, and wherein the treatment apparatus comprises at least one transfer apparatus, which moves the workpieces or groups of workpieces from the outlet opening to the inlet opening. 
   The treatment apparatus according to the invention makes it possible for even heavy workpieces with a sensitive surface to be moved in a controlled, damage-free manner within the levels of the treatment apparatus and during the transfer from one level to the next level. 
   At the same time, the advantages of the treatment apparatus known from DE 44 42 152 A1 are retained. 
   In particular, workpieces that are fed singly to the treatment apparatus remain single in the treatment apparatus and are discharged in the same time cycle. 
   The treatment apparatus according to the invention is comparable to a rectilinear throughfeed system, which has been wound up, and therefore has only a small footprint. 
   In a preferred development of the treatment apparatus according to the invention, it is provided that the workpieces or groups of workpieces are movable by means of the transfer apparatus in a defined spatial position from the outlet opening to the inlet opening. 
   It is moreover preferably provided that the workpieces or groups of workpieces in the first chamber level and/or in the second chamber level are moved through an angle of at least approximately 90°, preferably of at least approximately 180°, in particular of at least approximately 270°, about an axis of rotation of the treatment apparatus. 
   The workpieces or groups of workpieces in the first chamber level and/or in the second chamber level are moreover moved preferably through an angle of less than 360° about an axis of rotation of the treatment apparatus. 
   Preferably, all of the receiving chambers of the same chamber level rotate synchronously with one another. 
   In particular, it may be provided that all of the receiving chambers of the same chamber level are rigidly connected to one another. 
   It is further advantageous when at least two receiving chambers of different chamber levels rotate synchronously with one another. 
   In particular, it may be provided that at least two receiving chambers of different chamber levels are rigidly connected to one another. 
   In a preferred development of the treatment apparatus according to the invention, it is provided that all of the receiving chambers of all of the chamber levels rotate synchronously with one another. 
   In particular, it may be provided that all of the receiving chambers of all of the chamber levels are rigidly connected to one another. 
   The receiving chambers of the treatment apparatus may in particular be formed in that the treatment apparatus comprises a, preferably substantially cylindrical, chamber drum, which is rotatable about an axis of rotation of the chamber drum and comprises at least one bottom wall, which is constructed transversely of the axis of rotation, and at least two dividing walls, which are oriented transversely of the bottom wall. 
   In particular, it may be provided that the chamber drum comprises at least two bottom walls and at least one top wall, which is oriented transversely of the axis of rotation. 
   In order to separate the receiving chambers formed in the chamber drum in a fluid-tight manner from one another and from the environment of the receiving chambers, it is advantageously provided that the chamber drum is provided at its periphery with a surface seal. This allows the workpieces in the receiving chambers to be subjected to a treatment using a liquid or gaseous treatment medium. 
   Through the use of such a seal it is moreover possible to design at least one chamber level of the treatment apparatus as a lock, in which the workpieces are adapted in stages from an initial state to a new ambient state. The period of adaptation to the new ambient state may in this case be considerably longer than the time cycle, in which the workpieces or groups of workpieces fed to the treatment apparatus succeed one another. 
   The region of the treatment apparatus that has a lock function may extend over a plurality of levels of the treatment apparatus. 
   If the workpiece progression cycle is, for example, ten workpieces per second and the treatment apparatus comprises, for example, ten receiving chambers per level, then the speed of rotation of the receiving chambers is one revolution per second. If the lock region extends over three levels of such a treatment apparatus, then for the inward transfer operation approximately three seconds are available, this corresponding to 30 times the workpiece progression cycle. 
   The material of the surface seal preferably comprises a plastics material of low sliding friction, e.g. polyethylene. 
   The material of the surface seal may further comprise a fluoropolymer or a fluoropolymer compound, since these substances have a high chemical resistance and low friction. 
   Here, by a fluoropolymer compound in this description and in the accompanying claims is meant a mixture of at least one fluoropolymer and at least one organic or inorganic filler. Suitable examples of such fillers are, in particular, graphite, carbon, carbon fibres, bronze, molybdenum disulphide or organic fillers, in particular high-temperature-resistant thermoplastic materials and thermoset materials, e.g. polyamide. 
   As a fluoropolymer, polytetrafluoroethylene (PTFE) or a modified polytetrafluoroethylene is preferably used. Here, by a “modified polytetrafluoroethylene” is meant a substance, which is similar to PTFE and in which the molecular structure of the PTFE has been chemically modified by partially replacing the fluorine atoms of the PTFE with substituents. 
   So that differences in the thermal expansion of the material of the surface seal, on the one hand, and of the material of other components of the treatment apparatus, on the other hand, may be reduced or fully compensated, the surface seal is preferably provided with compensating recesses, wherein the compensating recesses comprise in each case at least one compensating region, which varies in width upon a change of temperature of the surface seal and/or upon loading of the surface seal with a mechanical stress. 
   This makes it possible to use the surface seal in a wide temperature range without any risk of fatigue. 
   In a preferred development of the surface seal, it is provided that at least some of the compensating recesses comprise in each case at least one compensating region, which has a longitudinal direction oriented transversely of, preferably substantially at right angles to, the peripheral direction of the chamber drum. 
   Alternatively or in addition thereto, it may be provided that at least some of the compensating recesses comprise in each case at least one compensating region, which has a longitudinal direction aligned substantially parallel to the peripheral direction of the chamber drum. 
   It is preferably provided that at least some of the compensating recesses comprise in each case at least two compensating regions. 
   In said case, it is particularly advantageous when in each case at least two compensating regions of a compensating recess have longitudinal directions oriented transversely of, preferably substantially at right angles to, one another. This allows differences of thermal expansion to be compensated both in the peripheral direction and in the axial direction of the chamber drum. 
   In a preferred development of the treatment apparatus according to the invention, it is provided that the compensating recesses of the surface seal comprise in each case at least one compensating region, which in the mounted state of the surface seal varies in width upon a change of the temperature of the surface seal in such a way that the difference between the thermal expansion of the surface seal and of the chamber drum is at least partially, preferably substantially fully, compensated. 
   It has moreover proved advantageous when at least some of the compensating recesses comprise a central region, into which open at least two compensating regions of the compensating recess open. 
   These two compensating regions that open into the central region of the same compensating recess advantageously have longitudinal directions oriented transversely of, preferably substantially at right angles to, one another. 
   So that the workpieces may be introduced into and removed from the receiving chambers of the chamber drum, the surface seal, in addition to the compensating recesses, advantageously has access openings, which in the mounted state of the surface seal afford access to receiving chambers of the chamber drum. 
   When the surface seal comprises webs, which separate these access openings from one another, at least some of the compensating recesses of the surface seal are preferably disposed in intersection regions of the webs. 
   In a preferred development of the treatment apparatus according to the invention, it is provided that the surface seal in the mounted state encircles the chamber drum. 
   It is particularly advantageous for the surface seal to be of an integral construction. Such an integral surface seal is particularly easy and time-saving to manufacture and mount and/or exchange, should maintenance be required. 
   The possibility of being able to seal off the receiving chambers from one another and from the environment by means of a single surface seal that embraces the chamber drum is a central advantage of the treatment apparatus according to the invention over the treatment apparatus known from DE 44 42 152 A1, in which the blades have to move relative to the bases of the treatment apparatus and it is therefore necessary additionally to provide a seal in each case for the upper edge and the bottom edge of each blade. 
   In the treatment apparatus according to the invention there is moreover no need to seal off the receiving chambers from a central rotary shaft of the treatment apparatus because the receiving chambers move together with the central torque shaft of the treatment apparatus. 
   The outer surface of the, preferably cylindrical, chamber drum is easy to machine. 
   The surface seal disposed on this peripheral surface of the chamber drum is readily accessible and easy to exchange. 
   To make maintenance of the treatment apparatus particularly simple, it is preferably provided that the receiving chambers are removable from the housing. 
   It is particularly advantageous when a plurality of receiving chambers form component parts of a chamber drum, which is removable as a whole from the housing. 
   So that the workpieces may rotate inside the respective receiving chamber during a processing treatment, in a preferred development of the treatment apparatus it is provided that at least one of the receiving chambers is provided with a workpiece support, by means of which the workpiece inside the receiving chamber is rotatable relative to the receiving chamber. 
   In particular, it may be provided that the workpiece is rotatable by means of the workpiece support about an axis of rotation that is aligned substantially parallel to the axis of rotation of the receiving chambers of the treatment apparatus. 
   As an alternative thereto, it may be provided that the workpiece is rotatable by means of the workpiece support about an axis of rotation that is oriented transversely of, preferably substantially at right angles to, the axis of rotation of the receiving chambers of the treatment apparatus. 
   There are many possible ways of setting the workpiece in rotation inside the receiving chamber. 
   For example, it may be provided that at least one of the receiving chambers is provided with a turning apparatus, which comprises means of picking off a rotational movement from an inner wall of the housing of the treatment apparatus. 
   Alternatively or in addition thereto, it may be provided that at least one of the receiving chambers is provided with a turning apparatus, which comprises a rotary shaft extending through a wail of the receiving chamber. 
   In order to be able to carry out a subsequent processing treatment of the workpieces in vacuo, it is advantageous when at least one chamber level of the treatment apparatus is designed as a vacuum lock. 
   It is particularly advantageous when the receiving chambers of the chamber level designed as a vacuum lock in the course of their movement from an inlet opening of said chamber level to an outlet opening of said chamber level are evacuated in a plurality of discrete stages. 
   By virtue of the multi-stage evacuation, a period that is extended compared to the workpiece progression time is available for creating the vacuum in each receiving chamber. Furthermore, the pressure difference and hence the leakage rate across the chamber seal are reduced by virtue of the multi-stage evacuation. 
   It is further advantageous when the receiving chambers of the chamber level designed as a vacuum lock in the course of their movement from an outlet opening of said chamber level to an inlet opening of said chamber level are aerated in a plurality of discrete stages. 
   It has further proved advantageous when in each case at least one of the receiving chambers of the chamber level designed as a vacuum lock that is on the way from the inlet opening of said chamber level to the outlet opening of said chamber level is connected in terms of gas to, in each case, one other receiving chamber of said chamber level that is on the way from the outlet opening of said chamber level to the inlet opening of said chamber level. This produces a gas short circuit between a not yet fully evacuated receiving chamber, which is on the way from the inlet opening to the outlet opening, and a not yet fully aerated receiving chamber, which is on hes way from the outlet opening back to the inlet opening. By virtue of such a gas short circuit some of the evacuation of the receiving chamber is already achieved without using a vacuum pump, so that the vacuum pump has to evacuate each receiving chamber only from an already reduced chamber pressure to the desired vacuum ultimate pressure. Furthermore, in this way the gas quantity that has to be pumped out of the receiving chambers by means of a vacuum pump is markedly reduced. 
   Further features and advantages of the invention are the subject matter of the following description and the graphic representation of embodiments. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  a diagrammatic horizontal cross section through a treatment apparatus; 
       FIG. 2  a diagrammatic vertical longitudinal section through the treatment apparatus of  FIG. 1 ; 
       FIG. 3  a diagrammatic view of a transfer apparatus for transferring workpieces between two chamber levels of the treatment apparatus; 
       FIG. 4  a diagrammatic vertical longitudinal section through the treatment apparatus, wherein a chamber drum of the treatment apparatus is being lifted out of a housing of the treatment apparatus; 
       FIG. 5  a diagrammatic developed view of a surface seal of the treatment apparatus in a cold mounted state; 
       FIG. 6  a diagrammatic plan view of a compensating recess of the surface seal of  FIG. 5 , the compensating regions of which are widened in the cold mounted state; 
       FIG. 7  a diagrammatic developed view of the surface seal of  FIG. 5  in a warm operating state; 
       FIG. 8  a diagrammatic plan view of a compensating recess of the surface seal, the compensating regions of which are narrowed in the warm operating state; 
       FIG. 9  a cutout-style diagrammatic plan view of the peripheral surface of a chamber drum of the treatment apparatus with a surface seal applied onto the chamber drum, before the surface seal has been extended by entrainment elements of the chamber drum; 
       FIG. 10  a cutout-style diagrammatic radial section through an edge region of the chamber drum with the applied surface seal, before the surface seal has been extended by means of the entrainment elements, viewed in the direction of the arrow  10  in  FIG. 9 ; 
       FIG. 11  a view as in  FIG. 9 , after the surface seal has been extended by means of the entrainment elements; 
       FIG. 12  a view as in  FIG. 10 , after the surface seal has been extended by means of the entrainment elements, viewed in the direction of the arrow  12  in  FIG. 11 ; 
       FIG. 13  a diagrammatic view of an apparatus for rotating a workpiece in a receiving chamber, wherein the turning apparatus comprises a drive shaft extending through a wall of the receiving chamber; 
       FIG. 14  a diagrammatic view of a turning apparatus for rotating a workpiece in a receiving chamber, wherein the turning apparatus is driven by means of frictional engagement with the housing of the treatment apparatus; and 
       FIG. 15  a diagrammatic horizontal section through a chamber level of the treatment apparatus that is designed as a vacuum lock. 
   

   Identical or functionally equivalent elements are denoted in all of the drawings by the same reference characters. 
   DETAILED DESCRIPTION OF THE INVENTION 
   A treatment apparatus for the processing treatment of workpieces  102 , which is illustrated in  FIGS. 1 to 8  and denoted as a whole by  100 , comprises a housing  104  having a circular disk-shaped base plate  106  and a hollow-cylindrical housing wall  108 , which extends in an upward direction from the upper side of the base plate  106  (see  FIG. 2 ). 
   The base plate  106  of the housing  104  rests on a plurality of posts  110 , which are supported on a subsurface (not shown). 
   In an upward direction the housing  104  is open. 
   Disposed in the interior of the housing  104  is a chamber drum denoted as a whole by  112 , which is rotatable about a substantially vertical axis of rotation  114 . 
   The chamber drum  112  at its bottom end comprises a circular disk-shaped drum base plate  116 , from the upper side of which a hollow-cylindrical hollow shaft  118  aligned coaxially with the drum base plate  116  extends in an upward direction. 
   The combined height of the drum base plate  116  and the hollow shaft  118  corresponds substantially to the height of the housing wall  108 . 
   From the outside of the hollow shaft  118  a plurality of annular disk-shaped base plates  120  and an annular disk-shaped top plate  122 , which is disposed on the top end of the hollow shaft  118 , extend outwards in radial and horizontal direction, wherein the base plates  120  are spaced apart in axial direction of the hollow shaft  118  from one another, from the drum base plate  116  and/or from the top plate  122 . 
   As may be seen from  FIG. 1 , vertical dividing walls  124  moreover extend outwards in radial direction from the outside of the hollow shaft  118 , wherein each of the dividing walls  124  is disposed in each case between two base plates  120 , between a base plate  120  and the drum base plate  116  or between a base plate  120  and the top plate  122 . 
   In each case, two vertical dividing walls  124 , a portion of the hollow shaft  118 , and two base plates  120  or one base plate  120  and the drum base plate  116  or one base plate  120  and the top plate  122  delimit a receiving chamber  126  of the chamber drum  112 . 
   The receiving chambers  126  that are disposed at the same height in the chamber drum  112  together form a chamber level  128  of the chamber drum  112 . 
   The treatment apparatus  100  illustrated by way of example therefore comprises a chamber drum  112  having six chamber levels  128 , each of which comprises eight receiving chambers  126 . 
   The number of receiving chambers  126  need not however be the same in every chamber level  128 ; rather, the number of receiving chambers per chamber level  128  may vary in any desired manner. 
   In particular, it may be provided that in one or more chamber levels one or more of the dividing walls  124  between successive receiving chambers  126  are omitted. 
   All of the receiving chambers  126  of the same chamber level  128  and the receiving chambers of different chamber levels  128  are connected to one another in a rotationally fixed manner so that they are rotatable jointly about the axis of rotation  114  of the chamber drum  112 . 
   For entrainment this turning apparatus, a rotary drive denoted as a whole by  130  is used, which comprises a rotary drive motor  132 , e.g. an electric geared motor, which is disposed on the underside of the base plate  106  of the housing  104 . 
   The output shaft  134  of the rotary drive motor  132  extends through a central through-opening  136  in the base plate  106  of the housing  104  and is connected in a rotationally fixed manner to the underside of the drum base plate  116  of the chamber drum  112 . 
   So that workpieces  102  may be introduced into the treatment apparatus  100 , the housing wall  108  is provided at the height of the uppermost chamber level  128   a  with an, e.g. four-cornered, inlet opening  138   a . The extent of the inlet opening  138   a  corresponds substantially to the extent of the mouth opening  140 —delimited by the vertical dividing walls  124 , the base plate  120  and the top plate  122 —of each of the receiving chambers  126  of the uppermost chamber level  128   a , so that the receiving chambers  126  of the uppermost chamber level  128   a  may be brought alternately into a loading position, in which the mouth opening  140  of the respective receiving chamber  126  is aligned with the inlet opening  138   a  in the housing wall  108 , as is shown in  FIG. 1  for the chamber  126   a.    
   After a workpiece  102  to be treated has been introduced through the inlet opening  138  into the receiving chamber  126  aligned in each case with the inlet opening  138 , the relevant receiving chamber  126  with the workpiece  102  disposed therein is rotated by the rotational movement of the chamber drum  112 —continuously or cyclically—through an angle of rotation of less than 360° about the axis of rotation  114  into a transfer position, in which the mouth opening  140  of the relevant receiving chamber  126  is aligned with an outlet opening  142 , which is disposed in the housing wall  108  likewise at the height of the uppermost chamber level  128   a . In  FIG. 1 , the receiving chamber  126   g  has just reached this transfer position. 
   Preferably, the angular distance between the outlet opening  142  and the inlet opening  138  of a chamber level  128  corresponds to the angle at circumference, over which one of the receiving chambers  126  or a plurality of receiving chambers  126  of the relevant chamber level  128  extends. 
   On the way between the inlet opening  138  and the outlet opening  142  the workpiece  102  disposed in the receiving chamber  126  may be subjected to any desired processing treatment. 
   These processing treatments may be, for example, heat treatments, in particular annealing treatments, such as e.g. the “soft annealing” of tubes, or drying treatments, such as e.g. the drying of an enamel coating of the workpiece  102 . 
   Other processing treatments may be, for example, sandblasting of a workpiece  102  or vapour coating of a workpiece  102 . 
   Other possible treatments of a workpiece  102  are, for example, washing treatments with aqueous or hydrocarbon liquids and/or treatments that have to be carried out under gas protection or in vacuo. 
   On each chamber level  128 , the workpiece  102  may be subjected to one or more of such processing treatment steps. 
   If a treatment medium for such a treatment is to be fed to the receiving chamber  126 , this occurs through feed connecting pieces  144 , which are disposed on the housing wall  108  at the angular position that is passed by the receiving chamber  126  at the desired treatment time. For removing a treatment medium from a receiving chamber  126 , discharge connecting pieces  146  are provided on the housing wall  108  and are offset relative to the respective associated feed connecting piece  144  by an angle of rotation that corresponds to the desired treatment period. 
   The discharge connecting piece  146  for a treatment medium however need not necessarily be situated at the same level as the feed connecting piece  144  for the same treatment medium. Rather, it may be provided that a treatment medium fed at one level of the treatment apparatus  100  is only discharged at a directly or indirectly succeeding level. 
   So that a workpiece  102  after passing through one level  128  of the treatment apparatus  100  may be transferred to a succeeding treatment level, the treatment apparatus  100  comprises a plurality of transfer apparatuses  148 , one of which is diagrammatically illustrated in  FIG. 3 . 
   The transfer apparatus  148  comprises a housing  150 , which is flange-mounted in a fluid-tight manner onto a fastening flange  152  of the housing  104  of the treatment apparatus  100 . 
   The fastening flange  152  surrounds a region of the housing wall  108  that surrounds the outlet opening  142  of a first chamber level  128   a  and an inlet opening  138  of a second chamber level  128   b , with the result that the fastening flange  152 , the housing  150  of the transfer apparatus  148  and the housing wall  108  of the treatment apparatus  100  form a closed chamber  154 , which connects the outlet opening  142  in a fluid-tight manner to the inlet opening  138 . 
   The transfer apparatus  148  further comprises a moving apparatus  156  for the workpiece  102 , which moving apparatus is disposed inside the chamber  154 . 
   The moving apparatus  156  comprises a movable workpiece receiver  158 , e.g. in the form of a movable fork  160 , which is displaceable in vertical direction by means of a chain hoist  162 . 
   The chain hoist  162  comprises e.g. a pull chain  164 , which is run via a driven chain wheel  166  and two deflection chain wheels  168 . 
   The chain hoist  162  together with the fork  160  is displaceable by means of a pneumatic piston  170  in radial direction of the chamber drum  112 . 
   The pneumatic piston  170  is held displaceably in a pneumatic cylinder  172  and may at its two end faces  174  be loaded alternately with an increased gas pressure in order to move the chain hoist  162  with the fork  160  disposed therein towards the axis of rotation  114  of the chamber drum  112  or away from the axis of rotation  114 . 
   The workpiece  102  that is to be transferred from the chamber level  128   a  to the chamber level  128   b  rests in the receiving chamber  126  of the chamber level  128   a  on spacers  176 , which are supported on the base of the receiving chamber  126 . 
   In order to receive the workpiece  102 , the fork  160  is lifted by means of the chain hoist  162  to the height of the chamber level  128   a.    
   Then the fork  160  is pushed by means of the pneumatic piston  170  through between the spacers  176  and under the workpiece  102 . 
   The fork  160  is then lifted slightly by means of the chain hoist  162 , with the result that the workpiece  102  is supported on the fork  160  and lifted off the spacers  176  of the receiving chamber  126 . 
   The fork  160  plus the workpiece  102  is then removed from the receiving chamber  126  of the chamber level  128   a  by means of the pneumatic piston  170  and lowered to the entry height of the chamber level  128   b  by means of the chain hoist  162 . 
   The fork  160  plus the workpiece  102  is then pushed by means of the pneumatic piston  170  into a receiving chamber  126 ′ of the chamber level  128   b.    
   By lowering the fork  160  by means of the chain hoist  162 , the workpiece  102  is deposited on the spacers  176  on the base of the receiving chamber  126 ′. 
   The pneumatic piston  170  then completely removes the fork  160  from the receiving chamber  126 ′, and the fork  160  is lifted by means of the chain hoist  162  to the level of the chamber level  128   a  in order to await and transfer the next workpiece  102  from the chamber level  128   a.    
   As the transfer apparatus  148  is fully enclosed, it is also possible for any treatment medium fed in the chamber level  128   a  to flow through the chamber  154  of the transfer apparatus  148  and on into the chamber level  128   b.    
   An equalization of pressure also occurs between the receiving chambers of chamber level  128   a  and chamber level  128   b  so that, in particular, a vacuum created in the chamber level  128   a  is maintained in the chamber level  128   b.    
   After the transfer of a workpiece  102  from one chamber level  128   a  to the next chamber level  128   b , the relevant workpiece  102  is conveyed in the chamber level  128   b  by rotation of the chamber drum  112  through an angle of less than 360° about the axis of rotation  114  to the outlet opening  142  of the chamber level  128   b.    
   The workpiece  102 , as it travels through this level of the treatment apparatus  100 , may be subjected to further processing treatments in the receiving chamber  126 ′. 
   On reaching the outlet opening  142  of the chamber level  128   b , the workpiece  102  by means of a further transfer apparatus  148 , which may be of a corresponding design to the previously described transfer apparatus  148 , is transferred to the inlet opening  138  of a further chamber level  128  or, if the chamber level  128   b  is the last level to be travelled through by the workpiece  102 , is removed from the treatment apparatus  100 . 
   In the previously described embodiment, travel through the levels of the treatment apparatus  100  is effected from top to bottom. It would of course also be equally possible for the workpieces  102  to be introduced first into the lowermost chamber level  128   f , then conveyed through the treatment apparatus  100  from the bottom up to the uppermost chamber level  128   a  and removed at this level from the treatment apparatus  100 . 
   Particularly if liquid or gaseous treatment media are used in the treatment apparatus  100  and/or if a vacuum is created inside the treatment apparatus  100 , a surface seal  178  has to be situated between the outer surface of the chamber drum  112  and the inner surface of the housing wall  108  in order to prevent a liquid or gaseous medium from flowing out of a receiving chamber  126  into vertically or horizontally adjacent receiving chambers  126  or into the environment. 
   This surface seal  178  is disposed in a rotationally fixed manner on the peripheral surface of the chamber drum  112  and moves together with the chamber drum  112  through the interior of the housing  104  of the treatment apparatus  100 . 
   The surface seal  178  takes the form of an integral wrapping foil seal. 
   A developed view of the surface seal  178  stretched onto the chamber drum  112  and in a cold mounted state (at room temperature) is illustrated in  FIG. 5 . 
   A developed view of the surface seal  178  in a warm operating state (at an operating temperature of e.g. 120° C.) is illustrated in  FIG. 7 . 
   The surface seal  178  is manufactured in the form of a foil from a sealing material produced from a fluoropolymer resin or a fluoropolymer compound. In particular, the surface seal  178  may be formed from a polytetrafluoroethylene (PTFE) foil. 
   As may be seen from  FIGS. 5 and 7 , the surface seal  178  is provided with substantially rectangular through-openings  180 , which in the mounted state of the surface seal  178  on the chamber drum  112  are each substantially coincident with a mouth opening  140  of a receiving chamber  126 . 
   The through-openings  180  are consequently arranged in a regular grid, wherein the number of rows  182  situated one above the other corresponds to the number of chamber levels  128  of the treatment apparatus  100  and the number of columns  184  of the grid corresponds to the number of receiving chambers  126  per chamber level  128 . 
   The through-openings  180  of the surface seals  178  are separated from one another by vertical webs  186  and by horizontal webs  188 , wherein the horizontal webs  188  and the vertical webs  186  intersect in approximately square intersection regions  190 . 
   In the mounted state of the surface seal  178 , the horizontal webs  188  extend along the peripheral direction  187  of the chamber drum  112  and the vertical webs  186  extend along the axial direction  189  of the chamber drum  112 . 
   As may best be seen from  FIGS. 5 and 6 , the surface seal  178  is provided in each intersection region  190  with a compensating recess  192 , which comprises a substantially circular central region  193 , from which two vertical compensating regions  194  in the form of vertical slots extend in an upward direction and in a downward direction and from which two horizontal compensating regions  196  in the form of horizontal slots extend to the left and to the right. 
   The through-openings  180  and the compensating recesses  192  are separated by a suitable separation method, e.g. by punching or cutting, from a substantially flat foil of the sealing material. 
   In a concrete embodiment, the thickness of the surface seal  178  is approximately 5 mm. The height of the chamber drum  112  and hence the height H of the surface seal  178  is, for example, approximately 1000 mm. The diameter of the chamber drum  112  is, for example, approximately 800 mm, so that the circumference of the chamber drum  112  and hence the length L of the surface seal  178  is approximately 2513 mm. In the embodiment, moreover, six chamber levels  128  and eight receiving chambers  126  per chamber level  128  are provided, so that the width of the vertical webs  186  and of the horizontal webs  188  is in each case approximately 30 mm. 
   The horizontal extent l and the vertical extent h of the compensating recesses  192  are preferably greater than the width of the vertical webs  186  and of the horizontal webs  188  respectively. 
   In a concrete embodiment, the vertical extent h of the compensating recesses  192  is, for example, approximately 40 mm. In the same embodiment, the horizontal extent l of the compensating recesses  192  is, for example, likewise approximately 40 mm. 
   The material of the surface seal  178  (e.g. PTFE or a PTFE compound) has a much higher coefficient of thermal expansion than the material of the chamber drum  112  (as a rule, a metal material, in particular a steel). In the course of warming from room temperature to an operating temperature of e.g. approximately 120° C., the surface seal  178  therefore expands by approximately 1% relative to the peripheral surface of the chamber drum  112 , i.e. in the previously described concrete embodiment by approximately 25 mm in the peripheral direction of the chamber drum  112  and by approximately 10 mm in the axial direction of the chamber drum  112 . 
   This difference in the thermal expansion of the surface seal  178 , on the one hand, and of the chamber drum  112 , on the other hand, is compensated by means of the compensating recesses  192  provided in the intersection regions  190  of the surface seal  178 . 
   As is evident from  FIGS. 5 and 6 , in the mounted state (at room temperature) the surface seal  178  stretched onto the chamber drum  112  is under a mechanical prestressing, because of which the compensating regions  194 ,  196  of the compensating recesses  192  are widened. 
   In particular, the vertical compensating regions  194  from their point-shaped tip  198  to their point of opening into the central region of the compensating recess  192  widen to a width b 1  of e.g. approximately 3 mm. In the mounted state at room temperature, the horizontal compensating regions  196  in each case from their tip  200  to their point of opening into the central region  193  of the compensating recess  192  widen to a width b 2  of e.g. approximately 1.5 mm. 
   By virtue of the greater thermal expansion of the surface seal  178  relative to the chamber drum  112  in the course of warming from room temperature to the operating temperature of e.g. approximately 120° C., the width of the vertical compensating regions  194  and of the horizontal compensating regions  196  decreases in the course of warming of the chamber drum  112  and of the surface seal  178  to the operating temperature until the width b 1  of the vertical compensating regions  194  and the width b 2  of the horizontal compensating regions  196  in the operating state is approximately equal to zero (see  FIG. 8 ). 
   In the operating state, therefore, the surface seal  178  lies against the outside of the chamber drum  112  in a substantially stress-free manner, in particular without stresses acting in the peripheral direction  187  of the chamber drum  112  or in the axial direction  189  of the chamber drum  112 . Thus, the surface seal  178  may be used in a wide operating temperature range without any risk of fatigue. 
   The surface seal  178  may easily be stretched onto the chamber drum  112  during manufacture of the treatment apparatus  100  or in the event of an exchange becoming necessary after a specific period of operation. 
   For this purpose, first the chamber drum  112  is lifted up out of the housing  104  of the treatment apparatus  100  in the manner shown in  FIG. 4 . 
   For this purpose, a lifting apparatus denoted as a whole by  202  may be used, which comprises a plurality of retaining rings  204 , which are fastened to the upper side of the top plate  122  and through which in each case a holding rope  206  is drawn. The top ends of the holding ropes  206  are connected at the point  208  to a bottom end of a carrying rope  210 , which is run via a stationary deflection pulley  212  and is liftable or lowerable by means of a motor-operated rope winch (not shown) in order to lift the chamber drum  112  out of the housing  104  or lower the chamber drum  112  again. 
   The surface seal  178  is designed in its dimensions to the warm operating state, i.e. designed in such a way that the vertical and horizontal slots of the compensating recesses  192  are closed in the warm operating state. 
   It is then possible in principle to lay out the surface seal  178  at the operating temperature onto the chamber drum  112 . To do so, however, the chamber drum  112  and the surface seal  178  have to be heated up to the operating temperature outside of the housing  104  of the treatment apparatus  100 , which—particularly in the case of the exchange of a surface seal  178  in the course of maintenance of the treatment apparatus  100 —is either impossible or possible only with difficulty. 
   Alternatively, however, the surface seal  178  in the cold state may initially be laid loosely onto the cold chamber drum  112  and then extended successively in the peripheral direction  187  and in the axial direction  189  of the chamber drum  112 . 
   The extension of the surface seal  178  in the peripheral direction  187  of the chamber drum  112  is effected by means of vertical entrainment plates  214  (see  FIG. 9 ), which are held by means of a plurality of—e.g. in each case two—fastening screws  216 , which engage by their shanks into vertically mutually spaced threaded blind holes  218  and penetrate in each case a through-hole  220  in the vertical entrainment plate  214 , on in each case one of the dividing walls  124  of the chamber drum  112 , namely in the region of the mouth opening  140  of a receiving chamber  126 , wherein an outer edge  222  of the respective entrainment plate  214  projects out in radial direction of the chamber drum  112  by a distance d, which is smaller than the thickness of the surface seal  178 , e.g. by approximately 3 mm, beyond the relevant dividing wall  124  (see  FIG. 10 ). 
   The requisite extension of the surface seal  178  in the axial direction  189  of the chamber drum  112  is effected by means of horizontal entrainment plates  224 , which are held in each case by means of a plurality of—e.g. in each case four—fastening screws  216 , which penetrate through-holes  220  in the horizontal entrainment plate  224  and are screwed into threaded blind holes  218  in the bottom wall or the top wall of a receiving chamber  126 , on the relevant bottom wall or top wall of the receiving chamber  126 , namely near the mouth opening  140  of the receiving chamber  126 , wherein an outer edge  222  of the horizontal entrainment plate  224  projects out in radial direction of the chamber drum  112  by a distance d′, which is smaller than the thickness of the surface seal  178 , e.g. by approximately 3 mm, out beyond the relevant base plate  120 ,  116  and/or top plate  122  of the chamber drum  112 . 
   At room temperature, the length L of the surface seal  178  is (e.g. 25 mm) shorter than the circumference of the chamber drum  112  and the height H of the surface seal  178  is (e.g. 10 mm) shorter than the height of the chamber drum  112 . 
   In the cold pre-mounted state of the surface seal, in which the surface seal  178  is subject to no external stresses, the compensating regions  194 ,  196  of the compensating recesses  192  of the surface seal  178  are (just as in the warm operating state) closed. 
   For stretching the surface seal  178  onto the chamber drum  112 , the surface seal  178  is initially placed with one of its vertical webs  186  onto a row of dividing walls  124  of the chamber drum  112 , which are disposed one below the other, and is fastened at this web  186  by means of the vertical entrainment plates  214  adjacent thereto to the chamber drum  112  by fully tightening the fastening screws  216  of the relevant vertical entrainment plates  214  until the entrainment plates  214  lie flat against the relevant dividing wall  124 . 
   The rest of the surface seal  178  is drawn initially only loosely round the chamber drum  112 , with the result that a gap that is at least 25 mm wide remains between the ends of the surface seal  178 . 
   Starting from the first vertical web  186 , by which the surface seal  178  has been fastened to the chamber drum  112 , the surface seal  178  at its—in the peripheral direction  187  of the chamber drum  112 —adjacent vertical web  186 ′ is extended by the anticipated thermal expansion by fully tightening (see  FIG. 11 ) the fastening screws  216  of the vertical entrainment plates  214 , which lie against the vertical web  186 ′ and initially still project by approximately 4 mm from the relevant dividing wall  124  (see  FIG. 9 ), until the respective associated vertical entrainment plates  214  lie flat against the relevant dividing wall  124 . In said case, the surface seal  178  is pulled apart at the vertical compensating regions  194  of the compensating recesses  192  disposed in the webs  186  and is therefore extended in the peripheral direction  187  of the chamber drum  112 . 
   As, in this case, only narrow web regions of the surface seal  178  that are situated alongside the vertical compensating regions  194  are slightly deformed, this extension of the surface seal  178  entails a much lower expenditure of force than would be the case if the whole vertical webs  186  in their overall width of e.g. approximately 30 mm had to be extended out of their material by the same amount (of e.g. approximately 3 mm). 
   In the same, previously described manner the surface seal  178  is fastened by its vertical webs, which succeed the vertical web  186 ′ in the peripheral direction  187  of the chamber drum  112 , to the chamber drum  112 . 
   The surface seal  178  is then extended successively in the axial direction  189  of the chamber drum  112 . 
   For this purpose, the surface seal  178  is fastened by a horizontal web  188  to a base plate  120  of the chamber drum  112  by fully tightening the fastening screws  216  of the adjacent horizontal entrainment plates  224  until the relevant horizontal entrainment plates  224  lie flat against the upper side and/or against the underside of the relevant base plate  120 . 
   The surface seal  178  is then extended in the axial direction  189  of the chamber drum  112  in that a horizontal web  188 ′, which is adjacent in vertical direction to the first horizontal web  188 , is fastened to a vertically adjacent base plate  120 ′, namely by fully tightening the fastening screws  216  of the horizontal entrainment plates  224  lying against the horizontal web  188 ′ until these entrainment plates  224  also lie flat against the underside and/or against the upper side of the base plate  120 ′. 
   In said case, the surface seal  178  is pulled apart at the horizontal compensating regions  196  of the compensating recesses  192  disposed in the region of the horizontal web  188 , with the result that the surface seal  178  is extended by the anticipated thermal expansion in the axial direction  189  of the chamber drum  112 . 
   The extension of the surface seal  178  in the axial direction  189  is then continued in that the surface seal  178  is fastened by a further horizontal web, which follows the web  188 ′ in the axial direction  189 , to a further base plate  120  or to the top plate  122  or to the drum base plate  116  of the chamber drum  112 . 
   Once all of the vertical webs  186  and all of the horizontal webs  188  of the surface seal  178  have been fastened by means of the entrainment plates  214 ,  224  to the chamber drum  112  and the surface seal  178  has therefore been fully spread onto the chamber drum  112 , mounting of the surface seal  178  on the chamber drum  112  is complete. 
   The chamber drum  112  may then be re-inserted into the housing  104  of the treatment apparatus  100  by means of the lifting apparatus  202 . 
   In a second embodiment of the treatment apparatus  100  illustrated in  FIG. 13 , the workpieces  102  passing through the treatment apparatus  100  are in at least one receiving chamber  126  not deposited onto stationary spacers  176  but received in a workpiece support  226 , which is rotatable about an axis of rotation  228  that is aligned radially relative to the axis of rotation  114  of the chamber drum  112 . 
   Rotation about the axis of rotation  228  is effected in said case by means of a rotary shaft  230 , which is fastened to a radially inner end wall  232  of the workpiece support  226  and supported rotatably on the hollow shaft  118  of the chamber drum  112 . 
   An end of the rotary shaft  230  situated inside the hollow shaft  118  is provided with a bevel gear  234 , which is in mesh with a stationary central bevel gear  236 , which is aligned coaxially with the axis of rotation  114  of the chamber drum  112  and connected to the upper side of the base plate  106  of the housing  104  of the treatment apparatus  100  by a vertical supporting tube  238 , which penetrates a through-bore  240  in the drum base plate  116 . 
   Consequently, upon a rotational movement of the hollow shaft  118  about the axis of rotation  114  of the chamber drum  112  the bevel gear  234 , which is in mesh with the stationary central bevel gear  236 , and hence the workpiece support  226  with the workpiece  102  accommodated therein rotate about the horizontal axis of rotation  228 . 
   So that the workpiece  102  may be removed from the workpiece support  226  by means of a transfer apparatus  148 , a plurality of spacers  242  are provided on the workpiece support  226  so that a movable workpiece receiver  158  of the transfer apparatus  148 , e.g. a movable fork  160 , may be moved into the space between the workpiece  102  and a wall of the workpiece support  226  in order to lift the workpiece  102  off the spacers  242  and move the workpiece  102  out of the workpiece support  226 . 
   In order to uncouple the speed of rotation of the workpiece supports  226  in the receiving chambers  126  from the speed of rotation of the chamber drum  112  about the axis of rotation  114 , it may also be provided that the central bevel gear  236 , which is constructed coaxially with the axis of rotation  114 , is not stationary but is supported rotatably relative to the housing  104  and comprises an independent rotary drive. 
   Otherwise, the second embodiment of a treatment apparatus  100  corresponds in construction and function to the first embodiment, to the above description of which reference is made in said regard. 
   A third embodiment of a treatment apparatus  100  illustrated in  FIG. 14  differs from the first embodiment in that the workpieces  102  in at least one receiving chamber  126  of the chamber drum  112  do not rest on stationary spacers  176  but are held in a workpiece support  246 , which is rotatable about an axis of rotation  244  that is aligned parallel to the axis of rotation  114  of the chamber drum  112 . 
   The workpiece support  246  comprises a rotating disk  248 , on the upper side of which spacers  250  are disposed, on which the respective workpiece  102  rests. 
   The underside of the rotating disk  248  is connected by a rotary shaft  252 , which is aligned coaxially with the axis of rotation  244  and supported (by means of non-illustrated bearings) rotatably on the base of the receiving chamber  126 , to a friction wheel  254 , the peripheral surface of which is in contact with the inner surface of the housing wall  108  of the housing  104  of the treatment apparatus  100 . 
   Upon a rotational movement of the chamber drum  112  about the axis of rotation  114 , the friction wheel  254 , owing to the frictional engagement between the friction wheel  254  and the housing wall  108 , rolls along the inner surface of the housing wall  108 , with the result that the friction wheel  254  and hence the workpiece support  246  are set in rotation about the axis of rotation  244 . 
   The spacers  250  of the workpiece support  246  allow a movable workpiece receiver  158  of the transfer apparatus  148  to be moved between the rotating disk  248  and the workpiece  102  in order to lift the workpiece  102  off the spacers  250  and then move the workpiece  102  out of the receiving chamber  126 . 
   Otherwise, the third embodiment of a treatment apparatus  100  corresponds in construction and function to the first implementation function, to the above description of which reference is made in said regard. 
   In a fourth embodiment of a treatment apparatus  100  illustrated in  FIG. 15 , at least one level of the treatment apparatus  100  has the function of a vacuum lock. 
   In the embodiment illustrated in  FIG. 15 , the relevant chamber level  128  is provided with sixteen receiving chambers  126 , which because of the rotational movement of the chamber drum  112  about the axis of rotation  114  are moved from the inlet opening  138  of the chamber level  128 , by which the chamber level  128  is in communication with the ambient atmosphere and through which the workpieces  102  are introduced into the chamber level  128 , to the outlet opening  142  of the chamber level  128 , which lies at an angular distance of 180° opposite the inlet opening  138  and at which the vacuum ultimate pressure of the chamber level  128  is reached and by which the chamber level  128  is connected to a following chamber level  128  that is likewise at least partially under vacuum. 
   Because of the rotational movement of the chamber drum  112 , the receiving chambers  126 —after removal of the workpieces  102  through the outlet opening  142 —are returned in the empty state to the inlet opening  138 . 
   On this level, each receiving chamber  126  therefore always travels from a region of high pressure (inlet opening  138 ) to a region having the vacuum ultimate pressure (outlet opening  142 ) and back again. 
   In the vacuum lock illustrated in  FIG. 15 , the vacuum is created in stages in that in each case an empty receiving chamber  126 , in which there is still a vacuum, is connected in a gas short circuit to a receiving chamber, which contains a workpiece  102  and in which the vacuum ultimate pressure has not yet been reached. 
   For this purpose, the housing wall  108  in a region that (in the direction of rotation  255 ) follows the inlet opening  138  is provided with a first air discharge connecting piece  256   a , which is connected by a first short-circuit line  258   a  to a first air feed connecting piece  260   a , which is disposed on the housing wall  108  (viewed in the direction of rotation  255 ) after the outlet opening  142  and before the inlet opening  138 . 
   A second air discharge connecting piece  256   b , which is disposed (viewed in the direction of rotation  255 ) after the first air discharge connecting piece  256   a , is connected by a second short-circuit line  258   b  to a second air feed connecting piece  260   b , which is disposed (viewed in the direction of rotation  255 ) before the first air feed connecting piece  260   a.    
   A third air discharge connecting piece  256   c , which is disposed (viewed in the direction of rotation  255 ) after the second air discharge connecting piece  256   b , is connected by a third short-circuit line  258   c  to a third air feed connecting piece  260   c , which is disposed (viewed in the direction of rotation  255 ) before the second air feed connecting piece  260   b.    
   A fourth air discharge connecting piece  256   d , which is disposed (viewed in the direction of rotation  255 ) after the third air discharge connecting piece  256   c , is connected by a fourth short-circuit line  258   d  to a fourth air feed connecting piece  260   d , which is disposed (viewed in the direction of rotation  255 ) before the third air feed connecting piece  260   c.    
   Disposed between the fourth air discharge connecting piece  256   d  and the outlet opening  142  of the chamber level  128  is a fifth air discharge connecting piece  256   e , which is connected by a suction line  262  to a vacuum pump (not shown). 
   A fifth air feed connecting piece  260   e  disposed between the first air feed connecting piece  260   a  and the inlet opening  138  of the chamber level  128  opens into the ambient atmosphere, so that the receiving chamber  126  situated in each case in the region of the fifth air feed connecting piece  260   e  is aeratable through the fifth air feed connecting piece  260   e  up to atmospheric pressure. 
   In the previously described chamber level  128  used as a vacuum lock, therefore, a short circuit between a not yet fully evacuated receiving chamber  126 , which is on the way from the inlet opening  138  to the outlet opening  142 , and a not yet fully aerated receiving chamber  126 , which is on the way from the outlet opening  142  back to the inlet opening  138 , is effected altogether four times. 
   Assuming an atmospheric pressure of e.g. 1000 mbar and a desired vacuum ultimate pressure of e.g. 10 mbar, the chamber pressure after the pressure equalization through the first short-circuit line  258   a  is still e.g. approximately 800 mbar, after the pressure equalization through the second short-circuit line  258   b  still e.g. approximately 600 mbar, after the pressure equalization through the third short-circuit line  258   c  still e.g. approximately 400 mbar and after the pressure equalization through the fourth short-circuit line  258   d  still e.g. approximately 200 mbar. 
   The vacuum pump therefore has to evacuate the receiving chamber  126  situated in the region of the fifth air discharge connecting piece  256   e  only from approximately 200 mbar to the desired vacuum ultimate pressure of 10 mbar. 
   By virtue of the multi-stage evacuation, the vacuum pump therefore has to pump far less gas out of the receiving chambers  126 . 
   Moreover, for the creation of the vacuum in a receiving chamber  126  a much longer period (given the use of 16 chambers in the chamber level  128  used as a vacuum lock, e.g. five times the workpiece progression cycle) is available for vacuum generation. 
   Furthermore, the pressure difference and hence the leakage rate through the surface seal  178  between receiving chambers  126  disposed successively in the peripheral direction  187  of the chamber drum  112  are also reduced by virtue of the multi-stage evacuation. 
   Otherwise, the fourth embodiment of a treatment apparatus  100  corresponds in construction and function to the first embodiment, to the previous description of which reference is made in said regard.