Abstract:
The invention relates to a melting apparatus ( 100 ) for melting paraffin ( 1 ), having: a melting container ( 110 ) for receiving paraffin ( 1 ) to be melted; a storage container ( 190 ) for storing molten paraffin ( 4 ); having a melting container heating device ( 120 ) for heating the melting container ( 110 ), having a storage container heating device ( 191 ) for heating the storage container ( 190 ), having a fluid connection ( 113 ) fluidically connecting the melting container ( 110 ) and the storage container; the melting container ( 110 ), the storage container ( 190 ), and the fluid connection ( 113 ) being arranged so that molten paraffin ( 4 ) flows out of the melting container ( 110 ) into the storage container ( 190 ).

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority of German patent application number 10 2016 202 506.0 filed Feb. 18, 2016, the entire disclosure of which is incorporated by reference herein. 
       FIELD OF THE INVENTION 
       [0002]    The present invention relates to a laboratory device having a melting apparatus for melting paraffin, and to a use of such a melting apparatus for melting paraffin. 
       BACKGROUND OF THE INVENTION 
       [0003]    DE 102 23 304 A1 discloses an apparatus for embedding samples in paraffin, having a pouring station and a reservoir container for the paraffin. The reservoir container is equipped with a heating device for melting paraffin in solid form. Here all of the paraffin is melted, and stored in a molten state during operation. 
         [0004]    DE 10 2008 054 071 A1 describes a tissue processor for processing tissue samples. The processor comprises, besides several chemical tanks, containers for liquid paraffin as well as a reservoir station for melting paraffin pellets or paraffin flakes. Molten paraffin can be pumped via conduits from the reservoir station into the containers. 
         [0005]    WO 2006/089365 A1 discloses a tissue processor having a reservoir container whose floor is equipped with a heating element, for melting paraffin blocks. The paraffin blocks can be stacked on one another, at first only the lower block being melted. Contact between the lower paraffin block and the heated floor is ensured by a weight on the paraffin blocks. A heating mandrel projecting into the melting container is furthermore provided as an additional heating element. 
         [0006]    US 2010/0167038 A1 discloses a melting apparatus for melting materials based on polyester, polyamide, polyolefin, or the like, by means of which apparatus motor vehicles can be coated with those materials. For this, the material is melted in a melting container and then conveyed into a storage container. 
         [0007]    EP 0 331 768 A1 discloses an apparatus for melting adhesive, in which a melting container is heated and the adhesive is then withdrawn therefrom by means of a pump. 
         [0008]    The known melting apparatuses are disadvantageous in that melting takes a relatively long time, and in the meantime it is not possible to withdraw liquid paraffin. Proceeding from this existing art, the intention is to shorten the melting time. 
       SUMMARY OF THE INVENTION 
       [0009]    The present invention proposes a laboratory device having a melting apparatus for melting paraffin, and a use of such a melting apparatus, having the features of the independent claims. Advantageous embodiments are the subject matter of the dependent claims and of the description that follows. 
         [0010]    In the context of the invention, a melting apparatus for melting paraffin, having a heated melting container for receiving paraffin to be melted and a heated storage container for storing molten paraffin, is presented, molten paraffin being capable of flowing out of the melting container into the storage container. In particular, the paraffin does not need to be pumped into the storage container. Thanks to the provision of two special containers, both melting and the delivery of paraffin to be melted, on the one hand, and the withdrawal of molten paraffin, on the other hand, can take place mutually independently and, in particular, simultaneously. It is not necessary to melt all the paraffin present in the melting container. Melting time and energy consumption are thereby reduced. The invention makes it possible for exactly a desired or predefinable quantity of molten paraffin always to be on hand in the storage container without requiring a great deal of energy for the purpose. 
         [0011]    The invention is used in laboratory devices, such as tissue processors (cf. WO 2006/089365 A1, DE 10 2008 054 071 A1, WO 2005/116609 A1) or automatic embedding machines (cf. DE 102 23 304 A1, DE 10 2007 022 014 A1). 
         [0012]    A very practical solution that is of simple design results if the melting container comprises an outflow to which a fluid conduit fluidically connecting the melting container and the storage container is connected. The molten paraffin can thereby always flow in very simple and direct fashion out of the melting container into the storage container. The outflow can comprise a valve in order to block the fluid connection. 
         [0013]    An outflow of this kind preferably likewise having a downward sloping floor, and/or a withdrawal pump, can likewise be provided for withdrawal of the molten paraffin from the storage container. 
         [0014]    According to the present invention the storage container comprises a measuring device for measuring the weight or volume of the molten paraffin. It is thereby possible in particular to implement a fill level monitoring function that allows exactly a desired or definable quantity of molten paraffin always to be on hand in the storage container. For example, if a value falls below a lower threshold value, a melting container heating device is activated and/or a valve between the melting container and storage container is opened. For example, when an upper threshold value is reached or exceeded, the melting container heating device can be deactivated and/or the valve can be closed. 
         [0015]    According to a preferred embodiment, the melting container comprises a floor that slopes downward toward the outflow. The molten paraffin can thereby reach the outflow independently and with no pumps or the like. For example, the floor can comprise a funnel-shaped and/or obliquely extending portion, or can be configured overall in a funnel shape or in the form of an oblique plane or a pyramid standing on its tip, or the like. 
         [0016]    Usefully, the melting container comprises a measuring device for measuring the weight and/or volume of the paraffin to be melted. As a result, the operator of the melting apparatus can be informed in timely fashion, for example by means of warning messages and/or warning signals, that paraffin to be melted is running short and must be refilled. Alternatively or additionally, automatic refilling from a reservoir container can also occur, for example by means of an automatic transport device (e.g. screw conveyor system) or bulk fill apparatus. 
         [0017]    The melting container heating device and/or the storage container heating device preferably comprise an inductor for inducing eddy currents in a floor and/or a wall of the container and/or in metallic bodies that are received in the container. Inductive heating has better efficiency and faster response times than resistance heating. The melting container heating device and/or storage container heating device can nevertheless also comprise one or more resistance heating elements. 
         [0018]    The melting container heating device is preferably arranged in the region of the outflow so that (only) the region around the outflow, for example the downward sloping region of the container floor, becomes heated. For example, the floor can be metallic at least in the region of the outflow, and can be heated inductively and/or by means of a resistance heating element. Because only a limited quantity of liquid paraffin is ever withdrawn from the melting container into the storage container in order to fill the latter, it is in particular not necessary to heat the entire melting container. 
         [0019]    In contrast thereto, the entirety of the storage container is preferably heated, for example by way of a (resistance- and/or inductively) heated floor or outer walls, and/or heating coils in the container. In particular, heating or warming of the molten paraffin in the storage container can make use of the feature of inductively heating a container floor and/or container walls, or arranging the liquid paraffin and metallic bodies in the storage container and then inductively heating the metallic bodies. Thanks to the extensive distribution of the metallic bodies in the liquid paraffin, the latter is heated not only from outside as in the case of conventional melting methods, but in its bulk, which is appreciably more energy-efficient. 
         [0020]    The metallic bodies preferably encompass particles and/or spheres and/or grid strips and/or ferromagnetic bodies, e.g. comprising iron, cobalt, nickel, and/or rare earths, and/or have a volume of less than 5 mm 3 , in particular of 2 to 3 mm 3 . The metallic bodies are preferably made of a non-corroding metal or have a coating made of a non-corroding metal. 
         [0021]    The metallic bodies preferably encompass metallic bodies mounted or inserted in the storage container, e.g. inserted, suspended, and/or skewered spheres and/or an inserted or mounted grid or the like. The volume of mounted or inserted metallic bodies is usefully greater than the volume of loose bodies. Provision can be made that the mounted bodies are mounted in the storage container detachably, for example for cleaning purposes. The metallic bodies can thus be reused, which makes this alternative very inexpensive. 
         [0022]    Further advantages and embodiments of the invention are evident from the description and the appended drawings. 
         [0023]    It is understood that the features recited above and those yet to be explained below are usable not only in the respective combination indicated, but also in other combinations or in isolation, without departing from the scope of the present invention. 
         [0024]    The invention is schematically depicted in the drawings on the basis of an exemplifying embodiment, and will be described in detail below with reference to the drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING VIEWS 
         [0025]      FIG. 1  very schematically shows an embodiment in principle of a melting apparatus according to the present invention. 
           [0026]      FIG. 2  very schematically shows a further preferred embodiment of a melting apparatus according to the present invention. 
           [0027]      FIG. 3  very schematically shows an alternative embodiment of a melting container for a preferred embodiment of a melting apparatus according to the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0028]      FIG. 1  very schematically shows an embodiment of a melting apparatus according to the present invention, which is labeled  100  in its entirety. 
         [0029]    Melting apparatus  100  comprises a melting container  110  for the reception of paraffin  1  to be melted, and a storage container  190  for storing molten paraffin  4 . The paraffin can be introduced or poured into melting container  110 , for example, in the form of blocks or plates, pieces, beads, pellets, flakes, etc. 
         [0030]    Melting container  110  comprises a floor having a funnel-shaped portion  111  that slopes downward toward an outflow  112 . A sieve  130  for retaining solid paraffin  1  is arranged at the outflow. A valve for blocking a fluid connection  113  between melting container  110  and storage container  190  can also be provided. 
         [0031]    With this embodiment it would also be conceivable to use funnel-shaped paraffin blocks. 
         [0032]    Melting container  110  is heated by a melting container heating device, configured here as a resistance heating element, in the region around outflow  112 . Paraffin melting on the heated portion  111  can thus flow downward (in the Figure) to outflow  112 , and from there to storage container  190 . 
         [0033]    An alternative embodiment of a melting container  110  is depicted in  FIG. 3 . Metallic bodies  4  are arranged in melting container  110  together with paraffin  1  to be melted. The metallic bodies can in particular be embedded as metallic particles in paraffin  1  to be melted, and/or they can be mounted in melting container  110 , for example in the form of an arrangement  4  of lined-up or skewered spheres or the like. 
         [0034]    In order to induce eddy currents in metallic bodies  4 , the melting apparatus comprises at least one inductor  120  that can be embodied in particular in the form of a flat induction coil. Inductor  120  is arranged below a floor of melting container  110 . 
         [0035]    For withdrawal or release of the molten paraffin into storage container  190 , melting container  110  comprises an opening having an optional valve  130 . 
         [0036]    Storage container  190  is heated by a storage container heating device  191  that is embodied, for example, as an inductor or induction coil that heats a metallic floor and/or metallic walls of storage container  190 , and/or metallic bodies arranged inside storage container  190 . Storage container heating device  191  can also comprise at least one resistance heating element. 
         [0037]    A weighing device  192  (W) is provided in order to measure the weight of molten paraffin  4  in storage container  190 . 
         [0038]    Weighing device  192  can be in communication with a control device  195  that is embodied to control melting container heating device  120  and/or a valve preferably arranged between melting container  110  and storage container  190 . When control device  195  recognizes that the quantity or mass of molten paraffin  4  has reached or fallen below a predefinable threshold value, control device  195  can preferably be configured to activate melting container heating device  120  and/or to open a valve (e.g.  130  in  FIG. 3 ) that is present. When control device  195  recognizes that the quantity of molten paraffin  4  has reached or exceeded a predefinable upper threshold, control device  195  can preferably be configured to deactivate melting container heating device  120  and/or to close the valve. 
         [0039]    A pump  193  (P) is provided for withdrawing molten paraffin  4  from storage container  190 . 
         [0040]      FIG. 2  very schematically depicts a further preferred embodiment of a melting apparatus  200  according to the present invention. Melting apparatus  200  comprises a melting container  210  in which paraffin  1  to be melted, and metallic bodies  2 , are arranged. Melting apparatus  200  furthermore comprises inductors, embodied as coil windings  220 , which are arranged behind a side wall of melting container  210 . The coil windings can be guided, for example, around melting container  210  as a cylindrical coil, or can be arranged as flat coils next to, for example, planar side walls. 
         [0041]    In the illustration depicted, melting container  210  comprises an oblique floor  211  that is tilted toward an outflow having a valve  230 . This configuration serves to allow very easy withdrawal of the molten paraffin from melting container  210  by opening a valve  230 . 
         [0042]    Arranged downstream from the valve is a storage container  300  for molten paraffin, which is also heated, for example by means of conventional resistance heating elements  310 . A fill level sensor  320  of storage container  300  serves to detect the fill level of the molten paraffin and, for example, can interact with valve  230  in such a way that valve  230  opens as soon as the fill level of the molten paraffin in storage container  300  reaches or falls below a predefinable lower threshold value, and/or closes as soon as the fill level of the molten paraffin in storage container  300  reaches or exceeds a predefinable upper threshold value. 
         [0043]    Melting container  210  comprises a separation apparatus embodied as a detachable sieve  250 , so that loose metallic particles  2  can be withdrawn from melting container  210 . An oblique intermediate floor  211  serves to guide the loose metallic bodies  2  into separation apparatus  250 , which can have a trough shape for collection of the loose metallic bodies. Intermediate floor  211  can be permeable to the paraffin. 
         [0044]    A sensor  260  for determining the quantity of loose metallic bodies  2  can be provided in order to ensure timely withdrawal of the metallic bodies. 
         [0045]    Melting apparatus  200  furthermore comprises a reservoir container  400  for paraffin  1  that is to be melted and has embedded metallic bodies  2 , from which container paraffin  1  that is to be melted and has embedded metallic bodies  2  can be conveyed via a feeder, e.g. a screw conveyor system  410 , into melting container  210 . 
         [0046]    Metallic bodies  2  are embodied, for example, as ferromagnetic particles that are embedded into the fragmented, in particular spherical or substantially spherical, paraffin. The size of metallic particles  2  is preferably in a range from 2 to 3 mm 3 . 
         [0047]    Ferromagnetic metallic bodies can be heated more easily by induction than non-ferromagnetic ones, and in particular can also be collected and disposed of, after melting, using a magnet.