Abstract:
A diverter valve for extruded materials, including a split cylinder in the cylindrical opening of a base, each cylinder half being independently pivotable. The base includes first and second inlets for first and second extruded material, and first and second outlets for the material. Base first and second flow paths carry the first and second extruded materials from the inlets to the output openings, and third and fourth flow paths carry extruded material from the first and second first inlet openings to the first and second outlets. The first and second inlet openings and the first and second output openings are axially open to the central opening, and the cylinder halves are adjacent along a plane substantially radial to the central opening axis with each of the cylinder halves including a recess open along the radial plane.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This is a non-provisional application claiming priority to U.S. Provisional Application Ser. No. 62/118,818, entitled “Diverter Valve” and filed on Feb. 20, 2015. 
     
    
     FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not Applicable. 
       MICROFICHE/COPYRIGHT REFERENCE 
       [0003]    Not Applicable. 
       FIELD OF THE INVENTION 
       [0004]    The present invention is related to continuous molding using multiple extruded materials, and more particularly to diverter valves for swapping the extruded materials between mold inputs. 
       BACKGROUND OF THE INVENTION 
       [0005]    Molding of extruded materials to form countless products is widely done. As is well known, an extruder is used to provide the extruded material to a suitable die in which the extruded material is shaped to create the desired object. Commonly, the object which is created has a uniform continuous shape, such as conduits, pipes and flat sheets. 
         [0006]    Extruded sheets, for example, may be formed from many different materials, with many different thicknesses, and with different layer constructions. An extruded sheet may be formed by itself or combined with one or more other sheet layers that are concurrently formed, or combined after formation. In a typical apparatus for extrusion forming of sheet products, a roll stand is placed downstream of an extruder assembly with an associated sheet die. Flowable material is delivered from one or more extruders through the sheet die to a nip/lamination location between adjacent rolls on the roll stand. 
         [0007]    Apparatuses for forming an extruded sheet products are shown, for example, in my U.S. Pat. No. 8,240,180, entitled “Height Positioning Mechanism for Roll Stand Assembly on an Apparatus for Continuously Forming an Extruded Sheet Product”; U.S. Pat. No. 8,021,140, entitled “Linear Bearing Assembly to Guide Movement of Roll Stand on Apparatus for Forming an Extruded Sheet Product”; U.S. Pat. No. 8,152,509, entitled “Gap Adjusting Mechanism for Rolls on a Roll Stand Used in the Extrusion Forming of a Sheet Product”; and U.S. Published Patent Application No. US-2010-0038037-A1, entitled “Apparatus for Applying a Film to a Bottom Side of an Extruded Sheet”. The disclosures of all of these patent applications are hereby fully incorporated by reference. 
         [0008]    Moreover, various products, including sheet products, can require the use of two separate materials, such as shown, for example, in U.S. Publ. Application No. US-2008-0314525-A1, entitled “Web Lamination System”, the disclosure of which is hereby fully incorporated by reference. Molding of such products requires the supply of material from at least a first extruder assembly and a second extruder assembly, with a first material provided by one and a second material provided by the other. It should be appreciated that use two different materials may from time to time be switched. For example, when the two materials differ in color, or in texture, it may be desirable to form a product (e.g., a sheet material) having one color or texture on its outer skin, and also to form a similar product but with the other color or texture on its outer skin. This may be accomplished by swapping the connection between the outputs of the extruder assemblies to the inputs of the mold. 
         [0009]    It should be appreciated, however, that swapping connections with continuous products may be most advantageously accomplished while molding continues, that is, while molding of the product continues. Moreover, it should be appreciated that continuing molding while swapping connections can result in bleed over and mixing of materials in the lines between the extruder assemblies and the mold. If, for example, one of the materials is hidden on the interior of a sheet, covered by the other material on the skin of the sheet, such mixing of materials in the unseen interior of the sheet may not be a major concern. However, similar mixing of the material which is molded to form the skin of the sheet can cause the sheet to have a different visible color than desired, either through some mixing of the colors or a speckling of one color with the other. Such an appearance is not only not what is desired, but it can give the appearance that the sheet was poorly manufactured, and possibly make the sheet unacceptable to a buyer. Therefore it is desirable to minimize the amount of molded product having mixed materials. 
         [0010]    My U.S. Pat. No. 8,490,643 discloses a diverter valve which overcomes one or more of the problems set forth above, as it may be used to provide advantageous operation whereby continuous molding may be done even while swapping extruders between multiple inputs. The present invention is directed to advantageously accomplishing the same. 
       SUMMARY 
       [0011]    The disclosed diverter valve controls input of supplies of first and second extruded materials to a mold for molding products including both extruded materials. The valve has two inlets and two outlets, and is configured to change between a first state wherein the first inlet is connected to the first outlet and the second inlet is connected to the second outlet, and a second state ( FIGS. 2 and 5 ) wherein the first inlet is connected to the second outlet and the second inlet is connected to the first outlet. The diverter valve is configured so that when switching from the first state to the second state, the first inlet is connected to the second outlet before disconnecting from the first outlet, and the second inlet is connected to the first outlet before disconnecting from the second outlet, and when switching the diverter valve from the second state to the first state, the first inlet is connected to the first outlet before disconnecting from the second outlet, and the second inlet is connected to the second outlet before disconnecting from the first outlet. 
         [0012]    In one aspect of the present invention, a diverter valve is provided for controlling input of supplies of first and second extruded materials to a mold. The valve includes a base having a central opening cylindrical about an axis, and a cylinder pivotable about the axis in the base cylindrical central opening. The base includes first and second inlets for first and second extruded material, and first and second outlets adapted to output extruded material to first and second mold inlets. The base has a first flow path adapted to carry the first extruded material from the first inlet to a first output opening, a second flow path adapted to carry a second extruded material from the second inlet to a second output opening, a third flow path adapted to carry extruded material from a first inlet opening to the first outlet, and a fourth flow path adapted to carry extruded material from a second inlet opening to the second outlet, with the first and second inlet openings and the first and second output openings axially open to the central opening. The cylinder has first and second recesses around its outer surface axially aligned with first and second inlet openings and the first and second output openings. 
         [0013]    In one form, when extruded material is supplied to the diverter valve, the material constantly flows through the entirety of the first, second, third and fourth flow paths and the first and second recesses. 
         [0014]    In another form, the cylinder is rotatable between first and second states. The first recess is open to the first output opening, and extends around the cylinder sufficiently whereby, (a) in the first state the first recess is open to the first inlet opening, (b) in the second state the first recess is open to the second inlet opening, (c) when transitioning from the first state to the second state the first recess becomes open to the second inlet opening before closing from the first inlet opening, and (d) when transitioning from the second state to the first state the first recess becomes open to the first inlet opening before closing from the second inlet opening. The second recess is open to the second output opening, and extends around the cylinder sufficiently whereby, (a) in the first state the second recess is open to the second inlet opening, (b) in the second state the second recess is open to the first inlet opening, (c) when transitioning from the first state to the second state the second recess becomes open to the first inlet opening before closing from the second inlet opening, and (d) when transitioning from the second state to the first state becomes open to the second inlet opening before closing from the first inlet opening. 
         [0015]    In an alternate form, the cylinder is rotatable between first and second states. The first recess is open to the first inlet opening and the second recess open to the second inlet opening. The first recess extends around the cylinder sufficiently whereby, (a) in the first state the first recess is open to the first output opening, (b) in the second state the first recess is open to the second output opening, (c) when transitioning from the first state to the second state the first recess becomes open to the second output opening before closing from the first output opening, and (d) when transitioning from the second state to the first state the first recess becomes open to the first output opening before closing from the second output opening. The second recess extends around the cylinder sufficiently whereby (a) in the first state the second recess is open to the second output opening, (b) in the second state the second recess is open to the first output opening, (c) when transitioning from the first state to the second state the second recess becomes open to the first output opening before closing from the second output opening, and (d) when transitioning from the second state to the first state becomes open to the second output opening before closing from the first output opening. 
         [0016]    In still another form, the cylinder has first and second halves independently pivotable about the axis in the base cylindrical central opening, the cylinder halves being adjacent along a plane substantially radial to the central opening axis with each of the cylinder halves including a recess open along the radial plane. 
         [0017]    In yet another form, the base first and second output openings and the base first and second inlet openings axially overlap the cylinder recesses. In a further form, the inlets are axially spaced on one side of the cylinder recesses and the outlets are axially spaced on the other side of the cylinder recesses. 
         [0018]    In another form, the base first and second output openings are open to opposite sides of the central opening. 
         [0019]    In still another form, the base first and second inlet openings are open to opposite sides of the central opening. In a further form, the first and second output openings are open to opposite sides of the central opening and spaced around the base central opening substantially equally between the first and second inlet openings. 
         [0020]    In yet another form, the cylinder recesses extend more than 180 degrees around the cylinder. 
         [0021]    In another form the first and second cylinder halves are selectively pivotable to selectively connect each of the first and second flow paths with at least one of the third and fourth flow paths. 
         [0022]    In still another form, the valve is configured to change between (a) a first state wherein the first inlet is connected to the first outlet and the second inlet is connected to the second outlet, and (b) a second state wherein the first inlet is connected to the second outlet and the second inlet is connected to the first outlet, wherein the diverter valve is configured so that (1) when switching the diverter valve from the first state to the second state, the first inlet is connected to the second outlet before disconnecting from the first outlet and the second inlet is connected to the first outlet before disconnecting from the second outlet, and (2) when switching the diverter valve from the second state to the first state, the first inlet is connected to the first outlet before disconnecting from the second outlet and the second inlet is connected to the second outlet before disconnecting from the first outlet. In a further form, the cylinder recesses are aligned with one another when the valve is in either of the first and second states. In a still further form, the cylinder has first and second halves independently pivotable about the axis in the base cylindrical central opening, the cylinder halves being adjacent along a plane substantially radial to the central opening axis with each of the cylinder halves including a recess open along the radial plane, with the cylinder halves being pivotable through 90 degrees, whereby (i) when switching the diverter valve from the first state to the second state, one of the cylinder halves is first pivoted 90 degrees in one direction and the other of the cylinder halves is thereafter pivoted 90 degrees in the one direction, and (ii) when switching the diverter valve from the second state to first state, one of the cylinder halves is first pivoted 90 degrees in the direction opposite the one direction and the other of the cylinder halves is thereafter pivoted 90 degrees in the opposite direction. 
         [0023]    In yet another form, the base comprises a tubular body inside a valve body wherein the tubular body inner surface is the cylindrical opening and the flow paths are in part defined by space between the tubular body and the valve body. 
         [0024]    In another aspect of the invention, a diverter valve is provided for controlling input of supplies of first and second extruded materials to a mold, including a base having a central opening cylindrical about an axis, and a cylinder pivotable about the axis in the base cylindrical central opening. The base has first and second inlet openings and first and second output openings open to the central opening, with first and second flow paths through the base adapted to carry first and second extruded material to the first and second output openings, and third and fourth flow paths through the base adapted to carry extruded material from the first and second inlet openings to inlets of a mold. The cylinder has first and second recesses around its outer surface axially aligned with the first and second inlet openings and the first and second output openings. 
         [0025]    In one form, when extruded material is supplied to the diverter valve, the material constantly flows through the entirety of the first, second, third and fourth flow paths and the first and second recesses. 
         [0026]    In another form, the base first and second output openings and the base first and second inlet openings axially overlap the cylinder recesses. In a further form, the base first and second output openings are open to opposite sides of the central opening, and the base first and second inlet openings are open to opposite sides of the central opening, the input and output openings being spaced about 90 degrees from each other. In a further form, the cylinder recesses extend more than 180 degrees around the cylinder. 
         [0027]    In still another form, the cylinder has first and second halves independently pivotable about the axis in the base cylindrical central opening, the cylinder halves being adjacent along a plane substantially radial to the central opening axis with each of the cylinder halves including a recess open along the radial plane. The first and second cylinder halves are selectively pivotable to selectively connect each of the first and second flow paths with at least one of the third and fourth flow paths. 
         [0028]    In another aspect of the invention, a diverter valve is provided for controlling input of supplies of first and second extruded materials to a mold, including a base having a central opening cylindrical about an axis and a cylinder having first and second halves pivotable through 90 degrees about the axis in the base cylindrical central opening. The base has first and second inlet openings and first and second output openings open to the central opening, with first and second flow paths through the base adapted to carry the first and second extruded material to the first and second output openings, and third and fourth flow paths through the base to carry extruded material from the first and second inlet openings to first and second inlets of a mold. The base first and second output openings are open to opposite sides of the central opening, and the base first and second inlet openings are open to opposite sides of the central opening, with the input openings being spaced about 90 degrees from the output openings. The cylinder halves are selectively pivotable to selectively connect each of the first and second flow paths with at least one of the third and fourth flow paths. The cylinder halves also are adjacent along a plane substantially radial to the central opening axis with each of the cylinder halves including a recess extend more than 180 degrees around the cylinder and axially open to the recess of the other cylinder half along the radial plane. The base first and second output openings and the base first and second inlet openings axially overlap the cylinder recesses. 
         [0029]    Other objects, features, and advantages of the invention will become apparent from a review of the entire specification, including the appended claims and drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0030]    The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee. 
           [0031]      FIG. 1A  is a perspective view of a diverter valve and control rods according to the present invention in a first (straight through) configuration, with the extruded material flowing through the valve shown at the input and output; 
           [0032]      FIG. 1B  is a view similar to  FIG. 1  wherein components are shown semi-transparently to illustrate interior passages in the diverter valve; 
           [0033]      FIG. 2A  is a view of the diverter valve of  FIG. 1  wherein components are shown semi-transparently to illustrate interior passages in the diverter valve; 
           [0034]      FIG. 2B  is a view similar to  FIG. 2A , but with the valve body removed; 
           [0035]      FIG. 3A  is a view similar to  FIG. 2A , but from a different orientation; 
           [0036]      FIG. 3B  is a view similar to  FIG. 3A , but with the valve body removed; 
           [0037]      FIG. 4  is a view of the central cylinder of the diverter valve of  FIG. 1 ; 
           [0038]      FIG. 5  is a top view of the diverter valve in the configuration as in  FIGS. 1A-4 , wherein components are shown semi-transparently to illustrate interior passages in the diverter valve; 
           [0039]      FIG. 6  is a view similar to  FIG. 4 , but with the upper half of he central cylinder pivoted as during transition between valve configurations; 
           [0040]      FIGS. 7A, 7B, 8A, 8B and 9  are views similar to  FIGS. 2A, 2B, 3A, 3B and 5 , respectively, but showing the valve in the transitional configuration away from the straight through configuration of  FIGS. 1-5 ; and 
           [0041]      FIGS. 10A, 10B, 11A, 11B, 12A, 12B and 13  are views similar to  FIGS. 1A, 1B, 2A, 2B, 3A, 3B and 5 , but showing the valve in the cross-over configuration following the transition of  FIGS. 6-9 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0042]    While this invention is susceptible of embodiment in many different forms, this specification and the accompanying drawings disclose only one specific form as an example of the use of the invention. The invention is not intended to be limited to the embodiment so described. 
         [0043]    For ease of description, the apparatus operating in accordance with this invention is described in the normal (upright) operating position, and terms such as upper, lower, horizontal, etc., are used with reference to this position. 
         [0044]    The apparatus of this invention can have certain conventional components and control mechanisms the details of which, although not fully illustrated or described, will be apparent to those having skill in the art and an understanding of the necessary functions of such components and mechanisms. 
         [0045]    Some of the Figures illustrating the preferred embodiment of the apparatus of the present invention show conventional structural details and mechanical elements or components that will be recognized by one skilled in the art. However, the detailed descriptions of such elements are not necessary to an understanding of the invention, and accordingly, are herein presented only to the degree necessary to facilitate an understanding of the novel features of the present invention. 
         [0046]    The diverter valve  10  includes three main parts: a base or valve body  20  having a central opening  24  (see  FIG. 5 ) cylindrical about an axis  26 , a tubular body  30  in the valve body opening  24 , and a split center cylinder  40  in the tubular body  30 . While the described embodiment has cylindrical and pivoting components as further described herein, it should be appreciated that an advantageous diverter valve embodying the present invention may also be provided using flat components shifting or reciprocating in a linear direction. 
         [0047]    The valve body  20  and the tubular body  30  are fixed relative to one another (and may be integral to one another, though it will be understood that convenience of manufacture will be facilitated by forming the tubular body  30  separate from the valve body  20 ). 
         [0048]    The cylinder  40  includes two halves  42 ,  44  which may be independently pivoted within the tubular body  30 . The cylinder halves  42 ,  44  each have flow path defining recesses at their adjacent ends, which recesses each extend over greater than 90 degrees around the cylinder halves  42 ,  44  as described in further detail below. Control rods  52 ,  54  (see  FIG. 1A ) may be pivoted about the axis  26  to control the position of the cylinder halves  42 ,  44 , respectively. 
         [0049]    The valve body  20  includes two input openings  202 ,  204  and two output openings  212 ,  214  therethrough, with the input openings  202 ,  204  spaced axially from the output openings  212 ,  214 . 
         [0050]    Description of the valve  10  will first be had with reference to  FIGS. 1A-5 , in which the two extruded materials  102 ,  104  pass through the valve  10  without crossing over, with material  102  entering input opening  202  and exiting through output opening  212 , and material  104  entering input opening  204  and exiting through output opening  214   
         [0051]    Material  102  flows through input opening  202  in valve body  20  to a recess  302  in the tubular body  30 . The recess  302  defines a path between the valve body central opening  24  and the tube body  30  which extends first annularly from the input opening  202  around the inside of the valve body central opening  24  (and the outside of the valve body  20 ) and then axially (i.e., in the direction of the axis of the cylindrical valve body and tubular body  30 ), with the upper end of the axially extending portion of the recess  302  having an axially extending output opening  312  through its inner side and open to the cylinder  40 . The output opening  312  is at a height between the height of the valve body input openings  202 ,  204  and the valve body output openings  212 ,  214 . 
         [0052]    Material  104  flows through input opening  204  in valve body  20  to a recess  304  in the tubular body  30 . The recess  304  defines a path between the valve body central opening  24  and the tube body  30  which extends axially with the upper end of the axially extending portion of the recess  304  having an axially extending output opening  314  through its inner side and open to the cylinder  40 . The tubular body output openings  312 ,  314  extend over substantially the same height and are aligned with each other. 
         [0053]    It should be appreciated that the recesses  302 ,  304  serve to allow the output openings  312 ,  314  from the cylinder  40  to be on substantially opposite axial sides of the central axis  26  even though the input openings  202 ,  204  are not. 
         [0054]    A second set of flow paths through the tubular body  30  also defined by recesses  332 ,  334  in the tubular body  30  are provided to allow flow from the interior of the tubular body  30  to the valve body output openings  212 ,  214 . Each of these recesses  332 ,  334  has an interior opening  342 ,  344  from which material  102 ,  104  may flow from flow paths in the cylinder  40  (as described below) and then to the valve body output openings  212 ,  214 . It should be appreciated that the recesses  332 ,  334  serve to allow the interior openings  342 ,  344  in the cylinder  40  to be on substantially opposite axial sides of the central axis  26  even though the connected output openings  212 ,  214  are not. 
         [0055]    The interior openings  342 ,  344  extend axially so as to overlap in the axial direction the output openings  312 ,  314 , at substantially equal 90 degree spacing around the axis  26 . 
         [0056]    Control of flow from the tubular body output openings  312 ,  314  to the valve body output openings  212 ,  214  is controlled by the position of the two cylinder halves  42 ,  44 . As previously noted, and as illustrated in  FIGS. 4 and 6 , the cylinder halves  42 ,  44  each have flow path defining recesses at their adjacent (vertical) ends. Specifically, the upper cylinder half  42  has recesses  412   a ,  414   a  on opposite sides of its lower end, each extending over greater than 90 degrees around the cylinder half  42 . The lower cylinder half  44  has recesses  412   b ,  414   b  on opposite sides of its upper end, each also extending over greater than 90 degrees around the cylinder half  44 . The recesses  412   a - b ,  414   a - b  are at the axial position (height) of the tubular body openings  312 ,  314 ,  342 ,  344 , so that in all angular positions of the cylinder halves  42 ,  44 , each recess  412   a - b ,  414   a - b  overlies to at least one (in some configurations during transitioning, as described below), and during normal operation (and some transitioning configurations) two, of the tubular body openings  312 ,  314 ,  342 ,  344   
         [0057]    In the configuration illustrated in  FIGS. 1A-5 , the cylinder halves  42 ,  44  are in the position illustrated in  FIG. 4 , with recesses  412   a ,  412   b  aligned with each other and recesses  414   a ,  414   b  aligned with each other. Moreover, in that configuration, the recesses  412   a ,  412   b  are aligned at opposite ends with the output opening  312  of the tubular body  30  and the output opening  212  of the valve body  20  so that material  102  will flow through the path between the recesses  412   a ,  412   b  and the inner surface of the tubular body  30  from tubular body output opening  312  to valve body output opening  212 , and from there to one side of the mold(s). Similarly, in that configuration, the recesses  414   a ,  414   b  are aligned at opposite ends with the output opening  314  of the tubular body  30  and the output opening  214  of the valve body  20  so that material  104  will flow through the path between the recesses  414   a ,  414   b  and the inner surface of the tubular body  30  from tubular body output opening  314  to valve body output opening  214 , and from there to the other side of the mold(s). 
         [0058]    Transitioning of the valve  10  as it is moved to the cross-over position (illustrated in  FIGS. 10A-13  and discussed below) is shown in  FIGS. 6-9 . Such transition occurs as the valve  10  is shifted from the materials  102 ,  104  flowing from input openings  202 ,  204  to output openings  212 ,  214 , respectively, to the cross-over configuration in which the materials  102 ,  104  flow from input openings  202 ,  204  to opposite output openings  214 ,  212 , respectively. 
         [0059]    During such transitioning, one of the cylinder halves (e.g., upper half  42 ) is first pivoted through 90 degrees, to the configuration shown in  FIG. 6  where the recesses  412   a ,  414   a  in the pivoted half  42  span between the recesses  412   b ,  414   b  as illustrated in  FIG. 6 , recess  414   a  spans between recess  412   b  and recess  414   b , and on the opposite side [not seen], recess  414   b  also spans between recess  412   b  and  414   b ). It should be appreciated that as that pivoting occurs, the recesses in the pivoting half  42  will to varying degrees open in their opposite ends to both recesses  412   b ,  414   b  in the other half  44  until, when fully pivoted, there will effectively be a generally sinuous open path completely around the outside of the cylinder  40  (see  FIG. 6 ) wherein both extruded materials  102 ,  104  exiting tubular body output openings  312 ,  314  may flow either way. Thus, in this transition, mixes of materials  102 / 104  will flow through the cylinder recesses  412   a ,  412   b ,  414   a  and  414   b  and out both valve body output openings  212 ,  214 . 
         [0060]    At this point in the transition, recess  414   a  of the pivoted cylinder half  42  has been shifted from the initial position ( FIGS. 1A-5 ) to a position in which it is on one end (but its opposite end) still open to tubular body output opening  314  but on the other end instead is open to (aligned with) valve body output opening  212  (rather than opening  214 ). Similarly, recess  412   a  of the pivoted cylinder half  42  has been shifted from the initial position to a position in which it is on one end (but its opposite end) still open to tubular body output opening  312  and on the other end instead is open to valve body output opening  214  (rather than opening  212 ). 
         [0061]    Transitioning to the cross-over configuration (illustrated in  FIGS. 10A-13 ) is then completed by pivoting the other cylinder half (e.g., lower half  44 ) through 90 degrees, wherein the recesses  412   b ,  414   b  will again line up fully with upper half recesses  412   a ,  414   a , respectively, to define two separate closed flow paths. In this configuration the closed flow path of recesses  414   a ,  414   b  connect tubular body output opening  314  to valve body output opening  212 , and the closed flow path of recesses  412   a ,  412   b  connect tubular body output opening  312  to valve body output opening  214 . 
         [0062]    Transitioning the configuration of the valve  10  back to the original configuration of  FIGS. 1A-5  is simply a reversal of the above described transition. 
         [0063]    It should be appreciated that at all times, including during transitioning, at no point is flow of either material  102 ,  104  into, through, and/or out of the valve  10  blocked, thereby allowing advantageous continuous operation without dead (i.e., periodically non-flowing) channels and stagnant polymers (which can degrade should it be temporarily stagnant). Thus, undesirable flow channel restrictions, flow stoppage, undesirable pressure spikes and/or defects in the molded articles resulting from degraded polymers can be avoided. 
         [0064]    It should similarly be appreciated that the diverter valve disclosed herein uses all flow channels continuously. That is, extruded material will flow through all of the flow channels at all times in all states of the valve, with there being no dead channels and/or places where the flow of material will even temporarily stop, and therefore no place for the extruded material to stagnate. 
         [0065]    It should still further be appreciated that in one alternate form the cylinder could be solid (i.e., unitary and not two halves), with two recesses defining separate flow paths (separated, e.g., axially). Advantageously, as with the illustrated split cylinder  40 , rotation of such a unitary cylinder would cause the recesses to shift so that each recess connects a flow inlet to one or the other flow outputs, or the connects a flow output to one or the other flow inlets. That is, each recess may be associated with one flow inlet and rotated to divert flow to one or the other flow outputs, or alternatively each recess may be associated with one flow output and rotated to change between connecting to one or the other flow inlet). Moreover, the recesses of such a unitary cylinder advantageously extend sufficiently around the cylinder periphery so that when transitioning between, for example, flow inlets, the recess will connect to (i.e., be open to) the new output to which it is changing before it disconnects from (i.e., is no longer open to) the output from which it is changing. It should be appreciated that by ensuring a constant, uninterrupted flow of extruded material through all flow paths, even as the flow paths change, dead channels which could house stagnant polymer will be eliminated, as will the undesirable effects of stagnant polymer such as blocking or reducing flow channels, defects in the molded articles, and pressure spikes.