Abstract:
An inertial gas-liquid impactor separator has a de-icer for preventing ice accumulation at the acceleration nozzles. A heater heats a nozzle plate to minimize plugging of acceleration nozzles otherwise due to icing.

Description:
BACKGROUND AND SUMMARY 
     The invention relates to inertial gas-liquid impactor separators for removing liquid particles from a gas-liquid stream, including in engine crankcase ventilation separation applications, including closed crankcase ventilation (CCV) and open crankcase ventilation (OCV). 
     Inertial gas-liquid separators are known in the prior art. Liquid particles are removed from a gas-liquid stream by accelerating the stream or aerosol to high velocities through nozzles or orifices and directing same against an impactor, typically causing a sharp directional change, effecting the noted liquid separation. Such inertial impactors have various uses, including in oil separation applications for blowby gases from the crankcase of an internal combustion engine. 
     Under cold conditions, water vapor in the blowby gas can freeze, which in turn may cause restriction or plug the smallest cross-sectional area through the system. The acceleration nozzles may thus be susceptible to ice accumulation and freeze-up. It is known in the prior art to prevent icing by heating the incoming gas-liquid stream upstream of the nozzles, for example as shown in U.S. Pat. No. 5,024,203, FIG. 10, at electrical heater 21 in inlet 11. 
     The present invention arose during continuing development efforts in the above technology, and provides various improvements, including another solution to the noted icing problem. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1 and 2  are taken from FIGS. 27 and 28, respectively, of commonly owned co-pending U.S. patent application Ser. No. 11/622,051, filed Jan. 11, 2007, incorporated herein by reference. 
         FIG. 1  is a sectional illustration of an inertial gas-liquid impactor separator. 
         FIG. 2  is like  FIG. 1  and shows a further operational condition. 
         FIG. 3  is a sectional illustration of an inertial gas-liquid impactor separator in accordance with the invention. 
         FIG. 4  is an enlarged view of a portion of  FIG. 3 . 
         FIG. 5  is an exploded perspective view showing a further embodiment. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows an inertial gas-liquid separator  510  for removing liquid particles from a gas-liquid stream  512 , for example oil particles from a blowby gas stream from crankcase  514  of internal combustion engine  516 . In such embodiment, the separator returns separated oil  518  at drain  520  to crankcase  514 , and returns separated air  522  at outlet  524  to air intake manifold  526  of the engine. In such application, it is desired to vent blowby gases from crankcase  514  of engine  516 . Untreated, these gases contain particulate matter in the form of oil mist and soot. It is desirable to control the concentration of the contaminants, especially if the blowby gases are to be recirculated back to the engine&#39;s air intake system, for example at air intake manifold  526 . The oil mist droplets are generally less than 5 μm in diameter, and hence are difficult to remove using conventional fibrous filter media while at the same time maintaining low flow resistance as the media collects and becomes saturated with oil and contaminants. The separator may be used in closed crankcase ventilation (CCV) systems and in open crankcase ventilation (OCV) systems, as well as other inertial gas-liquid impactor separator applications. 
     Separator  510  includes a housing  528  having an inlet  530  for receiving gas-liquid stream  512 , and an outlet  524  for discharging a gas stream  522 . The inlet may have a gasket such as O-ring  532  for sealed mounting to a component such as an engine crankcase. First and second flow branches  534  and  536  are provided through the housing from inlet  530  to outlet  524 . First flow branch  534  has a set of one or more nozzles  538  receiving gas-liquid stream  512  from inlet  530  and accelerating the gas-liquid stream in the first flow branch in a downstream direction through the first set of one or more nozzles  538  against a first inertial impactor collector  540  in the housing in the path of the accelerated gas-liquid stream through first flow branch  534  and causing liquid particle separation. Inertial impactor collector  540  in the housing is in the path of the accelerated gas-liquid stream and causes liquid particle separation by a sharp directional change as shown at  542 . In the preferred embodiment, impactor collector  540  has a rough porous collection or impingement surface causing liquid particle separation from the gas-liquid stream, and is like that shown in U.S. Pat. No. 6,290,738, incorporated herein by reference. In another embodiment, a smooth impervious impingement surface is used, providing a sharp cut-off size particle separation, as noted in the &#39;738 patent. Nozzles  538  may be provided by orifices having a venturi or frustoconical shape as in the &#39;738 patent. Second flow branch  536  has a second set of one or more nozzles  544  receiving the gas-liquid stream from inlet  530  and accelerating the gas-liquid stream in second flow branch  536  in a downstream direction through the second set of one or more nozzles  544  and against a second inertial impactor collector  546  in the housing in the path of the accelerated gas-liquid stream through second flow branch  536  and causing liquid particle separation by a sharp directional change as shown at  548 ,  FIG. 2 . A variable controller  550  in second branch  536  controls flow therethrough. 
     Variable controller  550 ,  FIGS. 1 ,  2 , in second flow branch  536  is responsive to pressure of gas-liquid stream  512 . Variable controller  550  in second flow branch  536  is upstream of the noted second set of one or more nozzles  544 . First and second flow branches  534  and  536  preferably diverge at a junction  552  downstream of inlet  530 , and variable flow controller  550  is preferably downstream of such junction  552 . First flow branch  534  is continuously open such that gas-liquid stream  512  can continuously flow therethrough and through the first set of one or more nozzles  538 . Variable flow controller  550  includes a valve  554  actuatable to control flow through second flow branch  536  and the second set of one or more nozzles  544 . Valve  554  is preferably a pressure relief valve responsive to increasing pressure of gas-liquid stream  512 . Valve  554  may be actuatable between open and closed positions respectively passing and blocking flow through second flow branch  536  and the second set of one or more nozzles  544 , which valve opens responsive to increasing pressure of gas-liquid stream  512 . Flow branch  534  provides a first stage, and one or more flow branches such as  536  provide second, third and so on stages, one of which is shown at  536 . Respective valves  554  may open at different pressures to provide a staggered sequentially opening multistage array providing staggered sequentially increasing flow area. In another embodiment, valve  554 , rather than on/off, may provide a variable opening variably increasing the size of the opening to variably increase flow area through second branch  536  in response to increasing pressure of gas-liquid stream  512 , including for example as in U.S. Pat. Nos. 7,238,216 and 7,473,291, both incorporated herein by reference. This multistage effect enables the above noted advantages including providing increased separation efficiency early in the life of the engine without suffering objectionably high pressure drop late in the life of the engine including end-of-life condition of the engine. 
     Gas-liquid stream  512  flows through the first and second sets of nozzles along parallel flow paths  534  and  536 . The noted first and second inertial impactor collectors  540  and  546  share in one embodiment a common impaction plate  556  at impaction zones  540  and  546  laterally spaced along a lateral direction  558  normal to the direction of flow  560  along each of the noted parallel paths. The distance  562  between the first set of nozzles  538  and the first inertial impactor collector  540  is constant. Variable flow controller  550  is movable to control flow through second branch  536 , and the distance  564  between the second set of one or more nozzles  544  and second inertial impactor collector  546  is constant, including during movement of variable flow controller  550 . Distance  562  is preferably equal to distance  564 . 
     First and second side-by-side chimneys  566  and  568  are provided in housing  528 . Each chimney defines a respective axially extending flow path therethrough, as shown at  534  and  536 . First chimney  566  has a first axial end  570  receiving gas-liquid stream  512  from housing inlet  530 , and has a distally opposite second axial end  572  having the first set of one or more nozzles  538  therethrough. First chimney  566  has a first axial flow passage  574  therethrough between first and second axial ends  570  and  572 , which axial flow passage  574  provides the noted first flow branch  534 . Second chimney  568  has a first axial end  576  receiving gas-liquid stream  512  from housing inlet  530 , and has a distally opposite second axial end  578  having the second set of one or more nozzles  544  therethrough. Second chimney  568  defines a second axial flow passage  580  therethrough between the first and second axial ends  576  and  578 , which axial flow passage  580  provides the noted second flow branch  536 . 
     Variable flow controller  550  is axially movable in second chimney  568 ,  FIGS. 1 ,  2 , along axial flow passage  580 . Variable flow controller  550  preferably includes a valve member  554 , which preferably includes a disc or the like, axially movable into and out of engagement with a valve seat  582  formed in second chimney  568 , to respectively close and open second flow branch  536 , as shown in  FIGS. 1 and 2 , respectively. Disc valve member  554  may include an annular gasket  584  for sealingly engaging valve seat  582 . Valve seat  582  is at the noted first axial end  576  of second chimney  568 . A biasing member such as helical compression spring  586  bears between the noted second axial end  578  of second chimney  568  and valve member disc  554  and biases valve member  554  to a normally closed position,  FIG. 1 , against valve seat  582 . Valve member  554  is axially movable upwardly to an open position,  FIG. 2 , in response to pressure of gas-liquid stream  512  overcoming the bias of biasing member  586 . Valve member  554  in the open position of  FIG. 2  permits flow of the gas-liquid stream axially as shown at arrow  588  through second chimney  568  to the second set of one or more nozzles  544  at the noted second axial end  578  of chimney  568 . 
       FIG. 3  shows an inertial gas-liquid impactor separator  600  for removing liquid particles from a gas-liquid stream. The impactor includes a housing  602  having an inlet  604  for receiving gas-liquid stream  512 , and an outlet  606  for discharging gas stream  522 . Nozzle plate  608  in the housing has one or more nozzles  610  receiving gas-liquid stream  512  from inlet  604  and accelerating the gas-liquid stream through the nozzles. An inertial impactor collector  612  in the housing is in the path of the accelerated gas-liquid stream and causes liquid particle separation from the gas-liquid stream, as described above. The flow then travels downwardly along internal dividing wall  614  and then into collection well or plenum  616 , from which the separated liquid may drain as shown at drain outlet  618 , and from which the separated gas or air may flow upwardly and then exit at outlet  606  as shown at arrow  522 . A heater  620 ,  FIG. 4 , in the housing heats nozzle plate  608  to minimize plugging of nozzles  610  otherwise due to icing. Heater  620  is downstream of inlet  604  and is thermally coupled to nozzle plate  608  such that the gas-liquid stream passes through inlet  604  unheated by heater  620 , whereafter the gas-liquid stream  512  is heated by contact with nozzle plate  608 . In one embodiment, the heater is an inductive heater, e.g. an annular or other shape band around and in contact with nozzle plate  608 , inductively heating the nozzle plate. The band has an inner surface engaging nozzle plate  608 , and an outer surface engaging and supported by chimney  566 . In a further embodiment, the nozzle plate is an electrically resistive element heated by electric current therethrough, whereby the heater is an electrical resistance heater and is provided by the nozzle plate itself. 
       FIG. 5  shows another embodiment wherein nozzle plate  630  has a first upstream side  632  facing the unheated incoming flow of the gas-liquid stream from the inlet, and a second downstream side  634  facing distally oppositely from the upstream side. One or more thermally conductive diffuser discs  636 ,  638  are provided on one or both respective sides  632  and  634 . The diffuser discs thermally conductively diffuse heat of the electrical resistance heater for rapid even heating of the nozzle plate. It is preferred that each side  632  and  634  of the nozzle plate  630  has its own respective diffuser disc  636  and  638  thermally conductively diffusing heat of the electrical resistance heater for rapid, even heating of the nozzle plate. Housing  602 ,  FIGS. 3 ,  4 , and housing  640 ,  FIG. 5 , have respective electrical conductor wires  642 ,  644 ,  FIG. 4 ,  646 ,  648 ,  FIG. 5 , passing into the respective housing for supplying electric current to the respective heater, for example at respective electrical connections  648 ,  650 . The wires are preferably sealed to the housing in gas-tight and liquid-tight relation. In one embodiment, the heater is preferably selected from the group consisting of an inductive heater, including a coil heater and a dielectric heater, a Peltier thermoelectric heater, and a passive heater, including a heat exchanger, for example such heat exchanger deriving heat from hot engine fluid from engine  516  in an internal combustion engine application. In further embodiments, the nozzle plate is a thermal conductor, e.g. aluminum, to efficiently and quickly distribute heat from an attached resistive heater. In further embodiments, as noted above, the nozzle plate is an electrically resistive element heated by electric current flow therethrough, whereby the heater is an electrical resistance heater and is provided by the nozzle plate itself. The electricity flows through the noted conductors to the resistive element which forms the acceleration nozzles, which element heats up when electricity flows through it. A metal plate, e.g.  636  and/or  638 , on one or both sides of the resistive element diffuses the heat for quicker, more even performance. 
     In the foregoing description, certain terms have been used for brevity, clearness, and understanding. No unnecessary limitations are to be inferred therefrom beyond the requirement of the prior art because such terms are used for descriptive purposes and are intended to be broadly construed. The different configurations, systems, and method steps described herein may be used alone or in combination with other configurations, systems and method steps. It is to be expected that various equivalents, alternatives and modifications are possible within the scope of the appended claims.