Patent Publication Number: US-2013239432-A1

Title: Apparatus and system for controlling the temperature of objects

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation application of international patent application PCT/EP2011/068780, filed Oct. 26, 2011, designating the United States and claiming priority from German application 10 2010 043 522.8, filed Nov. 5, 2010, and the entire content of both applications is incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to an apparatus and system for controlling the temperature of objects, in particular of workplaces, after a cleaning operation, in that the latter are subjected to an incident flow of gaseous fluid after the cleaning operation. The invention also relates to a method for controlling the temperature of the objects. 
     BACKGROUND OF THE INVENTION 
     For the quality and reliability of industrially produced products, it is important that workpieces in corresponding production processes are clean. In industry, use is therefore made of cleaning systems with liquid baths. In these baths, the workpieces are flushed in order to free them of swarf, lubricant, dust and chemicals. A good cleaning action can be achieved in this case in particular with hot cleaning liquids. The workpieces are heated in such cleaning liquids. It is then often necessary for steps In the production process which follow the cleaning that workpieces or else subassemblies are cooled. In modified processes, however, reverse operations can also be provided, in which a cooling operation is followed by a process-related (re)heating operation. 
     For controlling the temperature (cooling and/or heating) of workpieces in industrial production facilities, devices are known in which workpieces are moved through a tunnel continuously or in a clocked manner by means of a conveying system. In the tunnel, the workpieces are subjected to a temperature-controlled air flow. Here, however, there is the risk that cleaned workpieces become contaminated again, because dirt particles are often carried along in a temperature-controlled air flow owing to various treatment operations and fed to the tunnel. If the air flowing in such a tunnel has to be cooled with cooling units or heated with heaters, the operation of such devices additionally also leads to a high energy consumption. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to provide an apparatus and a system for controlling the temperature of objects, in particular of workpieces for use in an industrial production facility, which makes it possible to efficiently control the temperature of objects and workpieces without considerable contamination. 
     This object is achieved by an apparatus of the type mentioned above wherein a controlled temperature zone is formed as a cooling and/or heating zone and is formed in a chamber which can be subjected to a fluid flow which flows into the chamber. 
     The invention is based on the concept that objects, in particular workpieces, can also be cooled with the air flow which is circulated in a clean-room cell. The invention exploits the fact that the risk of contamination of workpieces by an air flow in such a clean room is not present if the supplied air to such a clean-room cell is filtered in order to keep the particle size and particle concentration in the cell below a predefined threshold value. 
     One concept of the invention is in particular that, by circulating purified gaseous fluid in a chamber, workpieces can be cooled in a manner which saves energy if the workpieces are subjected to an incident flow of slowly flowing fluid, for example, air, in the chamber over a relatively long time (for instance half an hour, several hours or even days). It is also a concept of the invention to move workpieces between spaced-apart production stations for efficiently cooling an industrial production facility in a clean-room cell with a circulated air flow. 
     In a further configuration of the invention, the controlled temperature zone is designed as a cooling and/or heating zone, wherein the controlled temperature zone is arranged in a chamber which is thermally insulated with respect to the environment, and wherein a fluid flow flows into the chamber through a filter preferably formed as a fine filter, in particular through a HEPA filter. A HEPA filter of the filter class H10 or higher in accordance with the European standard EN 18 22-1:1998 is preferably chosen as the filter in an apparatus according to the invention. Extremely small particles having a size of down to in the region of 0.3 μm can be filtered out in a HEPA filter. A HEPA filter therefore makes it possible in particular to free room air of fine dust, tobacco smoke, smoke, house dust, pollen, pores and odors. With a HEPA filter, it is possible to achieve overall degrees of separation of 99.9% for fine dust and suspended matter, that is, of 10000 dust particles, only three are not separated in a corresponding HEPA filter. A HEPA filter can be made up of a fine-mesh fabric of cellulose, synthetic fibers or glass fibers. Such fabrics are laid one on top of another with up to 1000 layers in a filter according to the invention. This provides a very large filter area. A particularly good filter action can be achieved by combining the HEPA filter with an activated carbon filter. This activated carbon filter is advantageously provided upstream of the HEPA filter. A pressure which is elevated compared to an ambient pressure (excess pressure) can be generated in the chamber by feeding in filtered, gaseous fluid. This ensures that no dust particles, dirt particles and liquid droplets can penetrate into the chamber from the outside from the environment. 
     In order that a fluid flow suitable for heating and/or cooling forms in the chamber, it is advantageous if the fluid flow flowing into the chamber through the filter is guided to at least one suction opening connected to the line system in the chamber. The fluid flow preferably flows in via the cover of the chamber. It advantageously runs through the controlled temperature zone to a suction extraction opening formed on a lateral portion of the chamber in the region of the bottom thereof. It is advantageous in particular if the flow of the fluid flow has an arc form in the controlled temperature sons. 
     In a further configuration of the invention, the chamber is connected to a line system for feeding gaseous fluid to the chamber and for carrying gaseous fluid away from the chamber and also for circulating the gaseous fluid in a circuit formed by way of the line system. In particular, it is a concept of the invention to circulate gaseous fluid for cooling or heating workpieces in a largely closed line system with a circuit. A heat exchanger for transferring heat into the fluid or out of the fluid is preferably provided in such a largely closed circuit, in which preferably more than 90% of the fluid is circulated. Fluid which is fed to the circuit is preferably pumped through a filter and introduced into the circuit at an elevated pressure compared to the environment. 
     A pump device is arranged in the line system for circulating fluid. This pump device can be formed, for example, as a Venturi nozzle connected to the compressed air system of an industrial production installation. A suitable pump device is also, however, a fan or compressor driven by electric motor. Using such a pump device, the gaseous fluid is sucked into the chamber through one or more suction openings and then fed to the filter. It is advantageous if the pump device is connected, to a further feed duct for feeding gaseous fluid into the line system. It is then possible in particular for an overpressure to be generated in the chamber. This has the effect, that no dust particles, dirt particles and liquid droplets can penetrate into the chamber from the outside from the environment. 
     It is advantageous in particular if the chamber is accommodated with the line system for circulating fluid in a transporting cabinet in the form of a container. In order that the apparatus can be moved in a simple manner in an industrial production facility, it is advantageous to provide this transporting cabinet or container with transporting elements in the form of rollers so that it can foe moved easily in the hall of a production facility. A transporting cabinet designed as a container preferably comprises transporting elements in the form of a means or a plurality of means nor the engagement of a fork of a forklift truck. With this measure, it is not only possible to control the temperature of workplaces as they are being moved between different production stations, but also an undesirable contamination of workpieces as they are being transported to stations in an industrial production facility is avoided. In order to make it possible here for fluid to be circulated even without connection to an electrical supply system, it is advantageous to integrate an electrical energy store, for example, a storage battery, in the transporting cabinet for operating a fan. 
     The chamber contains a holding device with a plurality of workpiece holders for receiving workpieces which are to be controlled in terms of temperature, in particular cooled. This holding device serves to hold the workpieces in the controlled temperature zone. If the chamber is formed with a columnar housing, this holding device can have, for example, workpiece holders with round storage bases, on which corresponding workpieces can be deposited. For the movement of such round storage bases in the chamber, the apparatus for cooling may have a drive. It is advantageous if the workpiece holders are formed for the cascading arrangement of the workpieces offset in relation to one another in the fluid flow. This has the effect that dirt, particles removed from a workpiece with the fluid flow are not carried to another workpiece and do not contaminate it in the controlled temperature zone. 
     In order to carry away the quantity of fluid moving via the further feed duct into the chamber, there are one or more openings for releasing gaseous fluid to the environment in the chamber. This ensures that dirt particles are flushed from the cooling zone of the chamber to the outside. 
     It is advantageous to arrange at least one flushing nozzle for flushing out the chamber with flushing liquid in the chamber. This makes it possible to easily and systematically clean the chamber of dirt particles. It is advantageous if the chamber has a device for collecting flushing liquid which has been fed into the chamber. This device for collecting flushing liquid which has been fed into the chamber can be connected to an installation for processing flushing liquid. 
     The apparatus for cooling objects and workpieces can be used, for example, as a clean room or else as an unload lock in final assembly. However, the apparatus for cooling is also suitable as a buffer store for workpieces in a production facility, in order to thereby set a consistent feed of workpieces. For loading objects, in particular workplaces, into and unloading them from the apparatus, the latter can be combined in particular with a handling robot to form a system. It is advantageous to feed objects or workpieces for cooling to the apparatus via a lock, such that no dirt particles are introduced into the cooling zone of the chamber. 
     With the apparatus or system for temperature control, the temperature of workpieces can be controlled between two production steps in an industrial production facility. For this purpose, for example, after a production step in a first production station and before a further production step in a second production station spatially separated from the first production station, a plurality of workpieces are arranged in the chamber having the controlled temperature zone. The workpieces arranged in the chamber are subjected there to an incident flow of gaseous fluid filtered by way of a fine filter in such a manner that dirt particles removed from a workplace with the gaseous fluid are not carried to another workpiece by the gaseous fluid. In this respect, it is possible in particular to move the workpieces in the chamber from the first production station to the second production station as the temperature is being controlled. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
       The invention will now be described with reference to the drawings wherein: 
         FIG. 1  is a first view of an apparatus for cooling workpieces; 
         FIG. 2  shows the apparatus for cooling workpieces with an additional handling apparatus; 
         FIG. 3  is a section view of the apparatus for cooling workpieces taken along line III-III of  FIG. 1 ; and, 
         FIG. 4  is a section of the apparatus along the line IV-IV of  FIG. 1 . 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION 
     An apparatus  10  for controlling the temperature of workpieces  16  as shown in  FIG. 1  has, according to a feature of the invention, a chamber  12 . The chamber  12  is located in a container  28  formed as a transporting cabinet. The chamber  12  surrounds a controlled temperature zone  14  in the form of a cooling zone, in which workpieces  16  can be cooled proceeding from an elevated temperature compared to ambient conditions. 
     The apparatus  10  contains a holding device for workpieces  16 , which has a plurality of workpiece holders ( 18 ,  20 ,  22 ). In the chamber  12 , workpieces  16  can be arranged on the workpiece holders ( 18 ,  20 ,  22 ) in the cooling zone  14  in a manner spatially offset in the manner of a cascade. 
     The transporting cabinet  28  has a sliding door  24 , The sliding door  24  can close off the chamber  12  so as to avoid the penetration of dirt particles into the cooling zone  14 . On that side, which lies opposite the sliding door  24 , the chamber  12  in the apparatus  10  has a closed wall  34 . The chamber  12  is accommodated in a container  28 . The container  28  has handling elements ( 30 ,  32 ). At the handling elements ( 30 ,  32 ), the container  28  can be held with the fork of a forklift truck. This makes it possible to move the container  28  in an industrial production installation. In order to make it possible for the container to be moved in a production facility, it is also possible, however, to mount the container  28  on rollers. 
       FIG. 2  shows the apparatus with an opened sliding door  24  and a handling robot  26 . Through the opened sliding door  24 , the handling robot  26  can be used to load the chamber  12  with workpieces  15  which have to be cooled. Correspondingly, cooled workpieces  16  can be removed from the chamber  12 . The introduction of dirt particles into the chamber  12  can be minimized by loading the workpieces  16  into the chamber  12  through an air lock  59 . 
       FIG. 3  shows the apparatus  10  as a section along the line III-III shown in  FIG. 1 . The side walls ( 36 ,  38 ) of the chamber  12  which adjoin the wall  34  are also closed. The chamber  12  is formed with a bottom portion  40 . The bottom portion  40  is funnel-shaped. The funnel-shaped bottom portion  40  opens into a pipeline  42 . The funnel-shaped bottom portion  40  acts as a device for collecting flushing liquid  75  which has been fed into the chamber  12 . 
     The chamber  12  has a cover  44 . There are openings in the form of air ducts  46  in the cover  44 . A HEPA filter  48  (High Efficiency Particulate Air Filter) is arranged on the cover  44 , The HEPA filter  48  is a fine-mesh ultrafine filter. It is a filter of the filter class H10 in accordance with the European standard EN 1822-1:1998. 
     The apparatus  10  contains a fan  52 . The fan  52  is arranged in a line system  54  for circulating gaseous fluid in the form of air in the chamber  12 . The gaseous fluid can be circulated in particular in the manner of a circuit through the line system  54 . At its pressure-side connection, the fan  52  is connected to the HEPA filter  48  by way of a funnel-shaped line portion  50 . For the dissipation of heat which the gaseous fluid has absorbed in the cooling zone  14 , there is a heat exchanger  57  in the line system  54 . This heat can be carried away to the area surrounding the apparatus  10  by means of the heat exchanger  57 . 
     The HEPA filter  48  can be subjected to blowing air by the fan  52  by way of a funnel element  50 . The line system  54  is connected to a feed duct  55  for ambient air. A controllable valve  64  is arranged in the feed duct  55 . By setting the valve  64 , ambient air can be added in a controlled manner to the circulating air conducted in the line system  54 . This makes it possible to set an overpressure in the chamber  12  by means of the fan  52 . This has the effect that no dust particles, liquid droplets and dirt particles can penetrate into the chamber  12  from the outside. There are suction extraction openings  56  for gaseous fluid in the chamber  12 . The suction extraction openings  56  are connected to the line system  54 . An air flow  58  with filtered air is formed in the chamber  12  upon operation of the fan  52 . The HEPA filter  43  filters dust, liquid or dirt particles from air, which pass from the line system  54  into the chamber  12 . The air flowing in via the ducts  46  in the cover  44  is moved through the chamber  12  with an arc-shaped flow. 
     With the arc-shaped flow, the air flows to the suction extraction opening  56  and to openings  62  in the sliding door  24 . The continuous feed of air through the HEPA filter  48  sets an overpressure in the chamber  12 . This overpressure ensures that no air contaminated with liquid droplets and dirt particles can penetrate into the chamber  12  from the outside. 
     The arc-shaped flow of the air flowing through the chamber  12  makes it possible to cool workpieces  16  which are arranged on the holders  18 ,  20  and  22 . The arrangement of the workpieces  16  in the chamber  12  in the manner of a cascade ensures that a workpiece  16  in the chamber  12  does not shade the air flow for another workplace  16 , and therefore each workpiece arranged in the chamber  12  can be subjected to an incident flow of air for cooling. 
     With the apparatus  10 , it is also possible for the degree of contamination of workpieces  16  in the chamber  12  to be improved by virtue of the air flowing in accordance with the flow  58 . Unlike in conventional apparatuses for cooling workpieces, the degree of contamination when cooling workpieces with gaseous fluid is thus reduced, that is, in no way impaired. 
     In order to remove dirt particles which are introduced into the chamber  12  by way of the workpieces  16  from the chamber  12 , there is a device  60  for flushing out the chamber with flushing liquid  75 . The device  60  comprises a line system  66 . The line system  66  connects flushing nozzles  58 , which are arranged in the chamber  12 , to a reservoir  70  for the flushing liquid  75 . The reservoir  70  is connected with the pipeline  42  to the chamber  12  at the funnel-shaped bottom portion  40  by way of a shut-off valve  71 . 
     The device  60  contains an assembly  55  for processing flushing liquid  75 . The assembly  65  includes a flushing pump  72  and a filter  74 . For flushing out the chamber  12  with flushing liquid  75 , the flushing pump  72  is activated. Then, dirt particles which have deposited on the closed walls ( 34 ,  36 ,  38 ) are flushed away with the flushing liquid  75  flowing out of the flushing nozzles  68 , and carried into the reservoir  70  by way of the funnel-shaped bottom portion  40 . The dirt particles are removed from the flushing liquid  75  here by the filter  14  upon circulation of the flushing liquid  75 . 
     In an industrial production facility, the apparatus  10  can be used in particular for transporting workpieces  16  between two or more different production stations and/or as a buffer store for workpieces  16  at a production station. 
     In summary, the following preferred features of the invention are noted in particular: an apparatus  10  for controlling the temperature of objects, in particular of workpieces  16 , after a deeming operation has a controlled temperature zone  14 , which is formed as a cooling and/or heating tone and in which the objects  16  can be subjected to an incident flow of gaseous fluid. The controlled temperature zone  14  is formed in a chamber  12  which can be subjected to a fluid flow  58  which flows into the chamber  12 . 
     It is understood that the foregoing description is that of the preferred embodiments of the invention and that various changes and modifications may be made thereto without departing from the spirit and scope of the invention as defined in the appended claims.