Abstract:
A system for separating a mixture of two fluids of different specific gravities comprising:
       a first chamber having an inlet for receiving said mixture;   a second chamber having a connection for receiving the fluid with the higher specific gravity of said mixture from said first chamber, said connection being situated between a portion of the two chambers below the inlet; and   a waste outlet in said first chamber to drain residue situated at an interface between the two fluids.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates generally to separating fluids of different specific gravities. 
       BACKGROUND OF THE INVENTION 
       [0002]    Many different systems for separating immiscible fluids of different specific gravities have been introduced over the years. These systems are useful for example in the disposal of water contaminated by other fluids such as oil, gasoline and antifreeze. In some cases such systems allow collecting both fluids. 
         [0003]    Typically these systems comprise two separate sides with a fluid path connecting them on the bottom. One side receives the mixture of the contaminated fluid. The lighter fluid rises to the top of the receiving side and the other side typically contains the heavier fluid. Outlets on each side allow discharge of the separated fluids. 
         [0004]    The mixture of the contaminated fluid is supplied to the device at a rate at which the system can separate the fluids in order to receive the correct fluids at the outlets. U.S. Pat. No. 5,637,234 to McCasland, the disclosure of which is incorporated herein by reference, describes apparatus and method for separating fluids having different specific gravities and for increasing the rate of separating the fluids. 
         [0005]    In some cases, in the separation system, at the interface between the lighter fluid and the heavy fluid, a fungus or combination fluid or other undesired material (such as colorants or other materials) develops or is collected (trapped), which is heavier than the light fluid and lighter than the heavy fluid. The waste is typically removed by emptying out the system or by dismantling it. 
         [0006]    In liquid toner printing systems, especially those in which the liquid toner is heated during the printing process, carrier liquid, which is lighter than water, is evaporated. Since this material is generally a hydrocarbon whose release into the atmosphere is restricted, some prior art systems have been known to condense the carrier liquid, together with moisture from a system enclosure, prior to venting air from the enclosure to the outside. 
         [0007]    In U.S. Pat. No. 4,538,899, carrier liquid evaporated from printed sheets, which may be mixed with water vapor is catalytically oxidized to provide a hot vapor. The hot vapor is used to heat a substrate to fix an image thereon. 
       SUMMARY OF THE INVENTION 
       [0008]    An aspect of some embodiments of the invention relates to a separation system with a waste outlet that allows draining the waste that develops between the lighter fluid and the heavier fluid. In some embodiments of the invention, the waste outlet is positioned directly below the position of the interface between the two fluids. In some embodiments of the invention the mixture is supplied at a high inlet above the waste outlet. Alternatively, the mixture is supplied at a low inlet below the waste outlet. In some embodiments of the invention, the position of the inlet is selected according to the fluid that is more preferentially being salvaged. For example in a water-oil system, a high inlet is preferred for salvaging oil and a low inlet is preferred for salvaging water. 
         [0009]    In an exemplary embodiment of the invention, the system is constructed with a secondary outlet for one or both of the fluids in order to protect the system from a clogged outlet and/or backflow of the fluid from its primary outlet. In some embodiments of the invention, the secondary outlet is positioned above the primary outlet. Alternatively, the secondary outlet is positioned at the same level, adjacent or opposite the primary outlet. 
         [0010]    In some embodiments of the invention, the system is constructed with a secondary purifying level for one or both of the fluids, to reach a higher level of purity of the fluid. 
         [0011]    There is thus provided, in accordance with an exemplary embodiment of the invention, a system for separating a mixture of two fluids of different specific gravities comprising: 
         [0012]    a first chamber having an inlet for receiving said mixture; 
         [0013]    a second chamber having a connection for receiving the fluid with the higher specific gravity of said mixture from said first chamber, said connection being situated between a portion of the two chambers below the inlet; and 
         [0014]    a waste outlet in said first chamber to drain residue situated at an interface between the two fluids. 
         [0015]    Optionally, the inlet is above said fluid interface. Alternatively, the inlet is below said fluid interface. 
         [0016]    In an embodiment of the invention, the system includes a first outlet for the fluid having the lower specific gravity in the reception chamber. Optionally, the system comprises a second outlet for the fluid having the higher specific gravity, in the second chamber. Optionally, the system comprises a third outlet in the second chamber, above the second outlet. Optionally, the third outlet is at the same height as the first outlet. Alternatively, the third outlet is at a lower height than the first outlet. 
         [0017]    In an embodiment of the invention, the system comprises a second outlet for the fluid having the higher specific gravity in the second chamber. Optionally, the system comprises a third outlet in the second chamber, above the second outlet. 
         [0018]    In an embodiment of the invention, the system comprises a separation unit connected to the first outlet. In an embodiment of the invention, the system comprises a fourth outlet from the first chamber, the fourth outlet being higher than the first outlet. 
         [0019]    In an embodiment of the invention, the system comprises a second level separation unit connected to the outlet of the fluid having the higher specific gravity. Optionally, the system comprises a drain outlet for the separation unit. 
         [0020]    There is further provided, in accordance with an embodiment of the invention, a system for separating a mixture of two fluids of different specific gravities comprising: 
         [0021]    a first chamber having an inlet for receiving said mixture; 
         [0022]    a second chamber having a connection for receiving the fluid having the higher specific gravity of said mixture from said first chamber, said connection being situated between a portion of the two chambers below the inlet; 
         [0023]    a first outlet in the second chamber for the fluid having the higher specific gravity; 
         [0024]    a second outlet in the first chamber for the fluid having the lower specific gravity, said second outlet being higher than the first outlet; and 
         [0025]    at least one additional outlet comprising one or both of 
         [0026]    a) an additional outlet in the second chamber, said additional outlet being higher than said first outlet and lower than said second outlet; and 
         [0027]    b) an additional outlet in the first chamber, said additional outlet being higher than said second outlet. 
         [0028]    Optionally, the at least one additional outlet comprises an additional outlet in the second chamber, said additional outlet being higher than said first outlet and lower than said second outlet. 
         [0029]    Optionally or additionally, the at least one additional outlet comprises an additional outlet in the first chamber, said additional outlet being higher than said second outlet. 
         [0030]    There is further provided, in accordance with an embodiment of the invention, a printing system comprising: 
         [0031]    an enclosure; 
         [0032]    a printing engine within said enclosure, in which liquid ink comprising a carrier liquid is used to produce images, some of said carrier liquid being evaporated during printing; 
         [0033]    a condenser that condenses liquid carrier from within the enclosure, together with moisture from air in the enclosure; 
         [0034]    a separator that receives the condensed mixture of carrier liquid and moisture and separates the carrier liquid from the moisture; and 
         [0035]    a conduit that delivers the separated carrier liquid to the printing engine for reuse. 
         [0036]    Optionally, the separator is a separator system according to the invention. 
         [0037]    There is further provided, in accordance with a preferred embodiment of the invention, a printing system comprising: 
         [0038]    an enclosure; 
         [0039]    a printing engine within said enclosure, in which liquid ink comprising a carrier liquid is used to produce images, some of said carrier liquid being evaporated during printing; 
         [0040]    a condenser that condenses liquid carrier from within the enclosure, together with moisture from air in the enclosure; 
         [0041]    a separator system according to the invention, that receives the condensed mixture of carrier liquid and moisture and separates the carrier liquid from the moisture. 
         [0042]    In an embodiment of the invention, the liquid ink is a liquid toner and wherein the liquid toner is heated during the printing, evaporating the carrier liquid. 
         [0043]    In an embodiment of the invention, the carrier liquid is a liquid hydrocarbon. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0044]    Particular non-limiting embodiments of the invention will be described with reference to the following description of embodiments in conjunction with the figures. Identical structures, elements or parts which appear in more than one figure are preferably labeled with a same or similar number in all the figures in which they appear, in which: 
           [0045]      FIG. 1  is a schematic illustration of a separation system with a low inlet according to an exemplary embodiment of the invention; 
           [0046]      FIG. 2  is a schematic illustration of a separation system with a high inlet according to an exemplary embodiment of the invention; 
           [0047]      FIG. 3  is a schematic illustration of a separation system with secondary outlets according to an exemplary embodiment of the invention; 
           [0048]      FIG. 4  is a schematic illustration of a separation system with a secondary purifying level according to an exemplary embodiment of the invention; 
           [0049]      FIG. 5  is a schematic illustration of an implementation of a separation system according to an exemplary embodiment of the invention; and 
           [0050]      FIG. 6  is a very schematic illustration of a liquid toner printing system, in accordance with an embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0051]      FIG. 1  is a schematic illustration of a separation system  100  according to an exemplary embodiment of the invention. In an exemplary embodiment of the invention, separation system  100  comprises a main chamber  10  and a secondary chamber  20 . Main chamber  10  and secondary chamber  20  are connected together at the bottom with a fluid connection path  50 . In some embodiments of the invention, chamber  10 , chamber  20  and connection path  50  are comprised from a single chamber, in which left and right sides  10  and  20  are separated, for example, by a baffle. In such a case connection path  50  is almost virtual since it is reduced to the width of the separation between the chambers. 
         [0052]    In an exemplary embodiment of the invention, a mixture of fluids  45  with different specific gravities, for example water and oil, are directed to a container  70 . Optionally, the mixture is physically, positioned higher than chamber  10  in order for it to be able to flow to separation system  100  by the force of gravity. Optionally, container  70  is connected by a conduit  60  to an inlet  95  on the lower part of chamber  10  above connection path  50 . Alternatively conduit  60  is connected to an inlet  95  on the upper part of chamber  10  as described below regarding  FIG. 2 . However, as indicated in the figure, the level of the input mixture will be between the heights of outlets  30  and  40 , based on the amount of each fluid in the mixture. 
         [0053]    Optionally a large tray such as container  70  is used to receive the mixture, as for example, when the source of the mixture is a condenser. Alternatively, the mixture can be piped directly into  10 . 
         [0054]    In an exemplary embodiment of the invention, on the upper part of chamber  10  there is an outlet  30  for the lighter fluid and on the upper part of chamber  20  there is an outlet  40  for the heavier fluid. In some embodiments of the invention, a continuous flow of mixture  45  is supplied to separation system  100 . The continuous flow enters chamber  10  and separates itself under the influence of the gravitational force. The heavier fluid  15  (e.g. water) sinks to the bottom of chamber  10  and the lighter fluid  25  (e.g. oil), rises to the top of chamber  10 . The heavier fluid  15  flows from chamber  10  through connection  50  to chamber  20  and flows out of outlet  40 . Lighter fluid  25  is blocked by the separation between chamber  10  and chamber  20  from spreading through the rest of separation system  100 , lighter fluid  25  rises to the top of chamber  10  and flows out through outlet  30 . 
         [0055]    In some embodiments of the invention, separation system  100  is initialized by filling it with the heavy fluid  15  in order to prevent mixture  45  from reaching chamber  20 , which would cause an initial output of some of lighter fluid  25  from outlet  40 . Alternatively, the initial flow from outlet  40  is optionally discarded until separation system  100  stabilizes, wherein chamber  20  comprises only heavy fluid  15 . To empty the system, a valve (not shown) is conveniently provided at the bottom of passage  50  or at the bottom of chamber  10  or chamber  20 . Opening this valve will empty the system. 
         [0056]    In an exemplary embodiment of the invention, the top of chamber  10  and/or chamber  20  and/or container  70 , are optionally vented to the atmosphere in order to prevent a build up of pressure on the fluids in the chambers. If not so vented, it may be desirable to connect the tops of chambers  10  and  20  to avoid air pressure differentials between the chambers. 
         [0057]    In an exemplary embodiment of the invention, at the interface between lighter fluid  25  and heavier fluid  15 , a layer  35  comprised of a fungus and/or an amalgam of the fluids or other undesired waste is formed due to a small amount of interaction between the two fluids although they are essentially immiscible. Additionally contaminants which are lighter than the heavier fluid but heavier than the lighter fluid will remain trapped between the two fluids. Layer  30  may comprise a gel. 
         [0058]    In some embodiments of the invention, a waste outlet  55  is positioned directly below the position of layer  35 , which is defined by the specific gravity of the two fluids. Optionally, waste outlet  55  is closed with a valve  65 , which is periodically opened for a short time, in order to dispose of contaminants that are trapped between the fluids. 
         [0059]    In an exemplary embodiment of the invention, outlet  30 , is positioned at a height P above the top of fluid connection path  50 . Optionally, P is selected tall enough to accommodate inlet  95 , outlet  55  and outlet  30  with spacing between them to accommodate a buildup of the various fluids between the ports ( 95 ,  55 ,  30 ). Optionally, a larger value of P will contribute to a finer separation of the fluids, since it allows for a longer flow path before exiting the system outlets. P can be increased if higher flow is desired. In addition, since separation of the fluids takes place in chamber  10 , this chamber should be made wide enough (or of a large enough diameter if round) to allow enough time for separation to take place, considering the flow rate. 
         [0060]    It should be noted that the system does not have any intrinsic limitation on flow rate. However, as the flow rate is increased, the amount of time the mixture remains in chamber  10  is decreased, so that separation may be incomplete. The dimensions should be adapted to take into consideration the purity desired, the flow rate expected and the speed with which the materials separate. 
         [0061]    The position J of the interface between the two fluids in chamber  10  below outlet  30  is determined by the height difference K of outlet  30  and outlet  40  and the value of the specific gravity of the fluids. The following equation shows the resulting relationship: 
         [0000]        J=K /(( SG ( H )− SG ( L )) 
         [0000]    SG(H)—specifies the specific gravity of the heavy fluid.
 
SG(L)—specifies the specific gravity of the light fluid.
 
         [0062]    In an exemplary embodiment of the invention, with water as the heavy fluid (SG(H)=1) and with an oil as the light fluid (e.g., SG(L)=0.75) the vertical distance of the position of the interface between the two fluids from the oil outlet  30  is 4 times the vertical distance of the water outlet from the oil outlet. Optionally, based on such a calculation waste outlet  55  is positioned below the interface position. The height outlet  55  above the top of conduit  50  is chosen to leave a quantity of heavier liquid in chamber  10 . When outlet  55  is open, the level of liquid in chamber  20  will fall as will the level of light liquid in chamber  10 . If the height of outlet  55  is too low, the lighter liquid will pass into chamber  20 , from which it can only be removed by draining the whole system. 
         [0063]      FIG. 2  is a schematic illustration of a separation system  200  with a high inlet according to an exemplary embodiment of the invention. In some embodiments of the invention, inlet  95  is positioned on the upper portion of chamber  10 , wherein mixture  45  enters separation system  200  into the volume containing lighter fluid  25 , as shown in  FIG. 2 . In a system with a high inlet  95 , heavy fluid  15  sinks to the bottom of chamber  10  and light fluid  25  remains in the upper volume. In a separation system  200  with a high inlet  95 , the position of the interface  35  between the fluids and correspondingly waste outlet  55  are positioned below inlet  95 , in contrast to being above inlet  95  in a separation system  100  with a low inlet  95 . 
         [0064]    In some embodiments of the invention, purification of one of the fluids is of more important and the other is less important. For example, one of the fluids may be expensive and/or it may be costly or hazardous to discard so it is salvaged for reuse (e.g. an expensive oil). Alternatively or additionally, one of the fluids may be a by-product, which needs to be cleaned to a reasonable level in order to be discarded (e.g. contaminated water). 
         [0065]    In some embodiments of the invention, separation system  200  is used to salvage lighter fluid  25  and optionally discard heavy fluid  15 . In such a case a high inlet is optionally used as shown in  FIG. 2 , to prevent lighter fluid  25  from collecting additional contaminants by passing through layer  35 . In such a case heavier fluid  15 , which is to be discarded will sink down through layer  35 . In contrast separation system  100  is optionally used to salvage heavy fluid  15  and optionally discard lighter fluid  25 . In separation system  100  a low inlet is used so lighter fluid  25  passes through layer  35  and heavier fluid  15  will optionally, be less contaminated. 
         [0066]      FIG. 3  is a schematic illustration of a separation system  300  with secondary outlets according to an exemplary embodiment of the invention. In some embodiments of the invention, an additional outlet  80  is provided as an auxiliary for outlet  30  and an additional outlet  90  is provided as an auxiliary for outlet  40 . The additional outlets  80 ,  90  serve as safeguard outlets for the respective primary outlets to prevent fluid mixing due to backflow from a disturbance in a primary outlet channel. Alternatively or additionally, the additional outlets serve to overcome clogging in the primary outlet. In some embodiments of the invention, additional outlets  80 ,  90  are positioned directly above their respective primary outlets, wherein optionally outlets  40  and  80  are positioned lower than outlets  30  and  90 , in order to prevent a backup of the denser fluid into the less dense outlet channels. Alternatively or additionally, additional outlets  80 ,  90  are positioned adjacent to the primary outlet or opposite the primary outlet in the same chamber. Optionally, additional outlets  80 ,  90 , serve in parallel with the primary outlet to provide backup to the fluid flow. 
         [0067]      FIG. 4  is a schematic illustration of a separation system  400  with a secondary purifying level according to an exemplary embodiment of the invention. In some embodiments of the invention, separation system  400  comprises a secondary purifying level to enhance the purity of the separated fluids.  FIG. 4  shows a secondary purifying level  85  for the heavier fluid. Optionally, secondary purifying level  85  comprises a “U” shaped system of the same size or different size such as provided by the first purifying level. 
         [0068]    In some embodiments of the invention, a secondary purifying level can be for the heavier fluid, the lighter fluid or both. In some embodiments of the invention, secondary purifying level  85  blocks any residue of lighter fluid  25  that managed to pass through with fluid  15  to chamber  20  or other contaminants. Optionally, the residue of lighter fluid  25  will be trapped at outlet  40  in chamber  20  as a result of its lighter specific gravity. In some embodiments of the invention, an escape outlet  105  with a valve  115  is added at the bottom of purifying level  85 , in order to allow periodic drainage of the trapped residue of lighter fluid  25  and other contaminants. 
         [0069]      FIG. 5  is a schematic illustration of an implementation of a separation system  500  according to an exemplary embodiment of the invention.  FIG. 5  shows separation system  500  constructed from standard plumbing pipes, connectors and fixtures, as known in the art. The plumbing elements may be standard ⅜″ ½″ or ¾″ (or other size) connectors and pipes or may be larger or smaller depending on the size required. The pipe may also be welded or soldered. 
         [0070]    In some embodiments of the invention, the system may be very large (e.g. several meters high) or very small (e.g. a few centimeters high), depending on the application. 
         [0071]    In some embodiments of the invention, the plumbing elements are comprised from standard plumbing materials as known in the art, for example plastic, rubber, copper and/or other metals or materials that are commonly used. 
         [0072]    In an exemplary embodiment of the invention, separation system  500  is supported by being attached to a supporting board  150 , to hold the elements of the system in place without relying on separating system  500  to support itself. Optionally, supporting board  150  can be the wall of a building or any solid structure. 
         [0073]    As described above for separation system  100 , separation system  500  comprises two pipe chambers  10  and  20  connected together on the bottom with a pipe  50 . Separation system  500  further comprises a lighter fluid outlet  30 , a heavy fluid outlet  40 , a mixture inlet  95  and a waste outlet  55  with a valve  65 . Optionally, chambers  10  and  20  are vented to the atmosphere to eliminate the buildup of pressure in the chambers. 
         [0074]    Similar to the secondary purifying level  85  for the heavy fluid, shown in  FIG. 4 , separation system  500  is shown with a secondary purifying level  120  for the lighter fluid. Residue of any heavy fluid or other contaminant that managed to exit from outlet  30  will be trapped in a pipe  130 , and blocked by a valve  125 . By periodically opening valve  125  the residue heavy fluid can be drained out. 
         [0075]    It some embodiments of the invention, separating system  100  can be constructed using other methods, for example, using a mold to create it from plastic, glass, asbestos or any other material, the same being flame resistant, if need be. 
         [0076]    In some embodiments of the invention, separating system  100  can be heated or constructed with built-in heating elements in order to accelerate the separation process of the fluids. 
         [0077]    In an exemplary embodiment of the invention, shown very schematically in  FIG. 6 , a liquid printing system  600 , has a print engine  602 , utilizing a volatile carrier liquid, which may, for example be, Isopar H, I, J, K or L or other volatile hydrocarbons or other volatile liquids. System  600 , generally includes an enclosure  601 , for keeping the evaporated liquid from escaping. Of course, openings are provided for the paper input and output, but otherwise, the printer is closed, except for inlets for air. During the printing process the carrier liquid evaporates and exits the printer through a ventilation system, generally shown at  604 . By cooling the air that exits through an air exit  606 , by passing the evaporated liquid, mixed with ambient air, past a cooling element  608  of a cooling system  610 , the carrier liquid, together with water from the ambient air is condensed. The carrier liquid can then be recovered for reuse in the printer and the water purified to an extent that it can be discarded without special precautions being taken. Optionally, a closed system can be constructed, as shown in  FIG. 6 , in which a separator  612 , which allows continuous use of the printer with little or no addition of oil, is part of the printer. Alternatively, the mixture of oil and water is removed and separated outside of the printer. Alternatively, it is separated in the printer, but not used in a closed loop replenishment system. 
         [0078]    In an exemplary embodiment of the invention, a separation system such as system  100 ,  200 ,  300 ,  400  or  500  shown in  FIGS. 1-5  is used as separator  612  to separate the fluids collected from the printing system. The oil collected by the system is reused by the printer and the water is discarded. 
         [0079]    The present invention has been described using non-limiting detailed descriptions of embodiments thereof that are provided by way of example and are not intended to limit the scope of the invention. It should be understood that features and/or steps described with respect to one embodiment may be used with other embodiments and that not all embodiments of the invention have all of the features and/or steps shown in a particular figure or described with respect to one of the embodiments. Variations of embodiments described will occur to persons of the art. 
         [0080]    It is noted that some of the above described embodiments may describe the best mode contemplated by the inventors and therefore include structure, acts or details of structures and acts that may not be essential to the invention and which are described as examples. Structure and acts described herein are replaceable by equivalents which perform the same function, even if the structure or acts are different, as known in the art. Therefore, the scope of the invention is limited only by the elements and limitations as used in the claims. When used in the following claims, the terms “comprise”, “include”, “have” and their conjugates mean “including but not limited to”.