Abstract:
A multiport valve is taught for regulating flow of liquid therethrough originating from at least two sources. The valve includes a three cylindrical valve chambers each having a piston residing therein such that through actuation of the pistons flow through each valve chamber can be permitted or stopped independently. There is an inlet port that tangentially intercepts the first cylindrical valve chamber and there is an outlet port that tangentially intercepts an intermediate cylindrical valve chamber. The design of the three valve chambers and the inlet and outlet ports to the valve chambers effectively eliminates any bubble traps in the valve and allows bubbles to be swept from the valve chambers.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates generally to valves for regulating the flow of fluids and, more particularly, to multiport valves for controlling flow of fluids from at least two sources to at least two destinations.  
         BACKGROUND OF THE INVENTION  
         [0002]    In the manufacture of coated web substrates, for example photographic films and papers, a liquid composition is coated via a specialized coating apparatus, typically a coating die or hopper, onto a moving web substrate. The composition, which may be one of several being coated simultaneously through the same hopper, is delivered to the hopper from a holding vessel via a solution delivery system. Current solution delivery systems in the photographic industry are highly automated and include a number of specialized valves for performing specific functions including, for example, changing flows between vessels, changing inline filters, purging of entrained air from the components of the system, and delivering coating compositions and flush water to the coating hopper.  
           [0003]    Bubbles in solution (in the form of entrained air) are a reality of the modem high speed methods to coat complex photographic films in papers. If not removed prior to coating, bubbles are a major source of machine down time and coated waste. A single bubble, 30 microns or larger can cause a coating defect and must be avoided. Bubbles may be introduced into coating solutions in many ways. Bubbles may be directly introduced as a result of voids or air pockets created in various system components. Bubbles may be the result of entrained gases present in the liquids flowing through the system. Bubbles may further be the result of dissolved gases released as components of the coating solutions are “melted” from the solid to the liquid state. As a result, bubbles must be effectively removed from the coating system to reduce coating waste.  
           [0004]    Bubbles are initially removed and minimized by known deaeration processes. Once the bubbles are removed from the coating solution, the coating solution delivery system is prepared. The solution delivery system (SDS) (lines and components) are prepared by first filling the system with deaerated high purity water at 40° C. This water fill step is designed to eliminate all air and bubbles from the SDS. In the next step, the water is displaced (purged) by bubble free coating solution. However, SDS components, particularly the valves, can be difficult to purge. Dead legs, threads, cracks, and valve cavities can all produce bubble traps that eventually release bubbles during the coating operation (as a result of a flow rate change, some other upset, or just by chance).  
           [0005]    Commercially available valves (ball valves, etc.) typically have many internal areas such as crevices, pipe threads, passageways, and valve chambers wherein air can be trapped and fail to be purged during a purge cycle with flush water. In addition, commercially available valves do not have all of the routing features needed for delivering both coating compositions and flush water to a coating apparatus. In particular, commercially available valves do not allow for purging of coating solution from the SDS to drain, while the coating hopper is draining or flushing independently of the SDS.  
         SUMMARY OF THE INVENTION  
         [0006]    It is therefore an object of the invention to provide an improved multiport valve wherein the potential for the trapping of air leading to the formation of bubbles is reduced.  
           [0007]    It is a further object of the invention to provide an improved multiport valve wherein residual coating composition may be readily removed by flush water.  
           [0008]    It is still a further object of the invention to provide an improved multiport coat select valve wherein the solution delivery system may be purged to drain while a connected hopper is draining or being flushed independent of the solution delivery system.  
           [0009]    Briefly stated, these and numerous other features, objects, and advantages of the present invention will become readily apparent upon a reading of the detailed description, claims and drawings set forth herein. These features, objects, and advantages are accomplished by a multiport valve for regulating flow of liquid therethrough originating from at least two sources comprising:  
           [0010]    a first cylindrical valve chamber having a first inlet port and a first outlet port, the first inlet port tangentially intercepting the first cylindrical valve chamber;  
           [0011]    a first piston residing in the first cylindrical valve chamber, the first piston being movable to engage and disengage with a first valve seat located at the first outlet port;  
           [0012]    a second cylindrical valve chamber having a second inlet port and a second outlet port;  
           [0013]    a second piston residing in the second cylindrical valve chamber, the second piston being movable to engage and disengage with a second valve seat located at the second inlet port;  
           [0014]    a primary liquid inlet port for delivering liquid to an internal conduit, the internal conduit connecting with and being coaxial with the second inlet port, the internal conduit also connecting with and being coaxial with a alternative inlet port in an intermediate cylindrical valve chamber, the intermediate cylindrical valve chamber having a third inlet port and a third outlet port, the third inlet port being connected to and coaxial with the first outlet port, the third outlet port tangentially intercepting the intermediate cylindrical valve chamber; and  
           [0015]    a third piston residing in the intermediate cylindrical valve chamber, the third piston being movable to engage and disengage with a third valve seat located at the alternative inlet port.  
           [0016]    The multiport valve of the present invention is preferably oriented such that the third outlet port is substantially horizontal and tangentially intercepts the intermediate cylindrical valve chamber at a top surface thereof. Each of the valve seats are positioned in a respective end wall of the cylindrical valve chambers. The transition from cylindrical wall to end wall should be radiused.  
           [0017]    The first inlet port, tangentially intercepting the first cylindrical valve chamber, creates a swirling or sweeping flow path through the first cylindrical valve chamber allowing bubbles to be swept therefrom. Similarly, the third outlet port, tangentially intercepting the intermediate cylindrical valve chamber, creates a swirling or sweeping flow path through the intermediate cylindrical valve chamber allowing bubbles to be swept therefrom. In addition, the tangential connections aid in avoiding bubble traps in the valve chambers.  
           [0018]    It is preferred that each of the pistons is independently controlled and actuated. This allows for selection of flow path therethrough originating from one of two sources and transmitted to one of two destinations. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]    [0019]FIG. 1 is a perspective view of the multiport valve with actuators attached thereto.  
         [0020]    [0020]FIG. 2 is a perspective view of the multiport valve body without the actuators attached thereto.  
         [0021]    [0021]FIG. 3 is a top view of the valve body shown in FIG. 2.  
         [0022]    [0022]FIG. 4 is a front view of the valve body shown in FIG. 2.  
         [0023]    [0023]FIG. 5 is a bottom view of the valve body shown in FIG. 2.  
         [0024]    [0024]FIG. 6 is a right end view of the valve body shown in FIG. 2.  
         [0025]    [0025]FIG. 7 is an exemplary cross-sectional view of a cylindrical valve chamber.  
         [0026]    [0026]FIG. 8 is an exemplary cross sectional view of a valve chamber with an actuator mounted thereon and a valve piston extending into the valve chamber.  
         [0027]    [0027]FIG. 9 is a generic cross sectional view showing connection between an external conduit and a port in the valve body.  
         [0028]    [0028]FIG. 10 is a flow schematic of the flow paths through the multiport valve.  
         [0029]    [0029]FIG. 11 is a cross-sectional view taken along line  11 - 11  of FIG. 3.  
         [0030]    [0030]FIG. 12 is a cross-sectional view taken along line  12 - 12  of FIG. 4. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0031]    Turning first to FIGS. 1 through 6 there is shown the multiport valve  10  of the present invention. The multiport valve  10  includes a valve body  12  and is shown in FIG. 1 with three actuators  14  mounted thereto. Valve body  12  (see FIGS.  2 - 6 ,  11 ,  12 ) is preferably formed by machining from a single blank, for example, stainless steel, titanium aluminum alloy, or plastic. Thus, valve body  12  is one integrally fabricated component.  
         [0032]    There is a first cylindrical valve chamber  16  formed in valve body  12  having a first inlet port  18  and a first outlet port  20 . The first inlet port  18  tangentially intercepting the first cylindrical valve chamber  16 . There is a first valve seat  22  located at the first outlet port  20 .  
         [0033]    There is a second cylindrical valve chamber  24  formed in valve body  12  having a second inlet port  26  and a second outlet port  28 . The second inlet port  26  may tangentially intercept the second cylindrical valve chamber  24 . There is a second valve seat  30  located at the second inlet port  26 .  
         [0034]    Valve body  12  further includes a primary liquid inlet port  32  for delivering liquid to an internal conduit  34  formed in valve body  12 . Internal conduit  34  connects with and is coaxial with the second inlet port  26 . The internal conduit  34  also connects with and is coaxial with a alternative inlet port  36  accessing an intermediate cylindrical valve chamber  38 . The intermediate cylindrical valve chamber  38  has a third inlet port  40  and a third outlet port  42 , the third inlet port  40  being connected to and coaxial with the first outlet port  20 . The third outlet port  42  tangentially intercepts the intermediate cylindrical valve chamber  38 . There is a third valve seat  46  located at the alternative inlet port  36 .  
         [0035]    Looking next at FIGS. 7 and 8 there is shown an exemplary cross-sectional view of the three cylindrical valve chambers  16 ,  24 ,  38 . FIG. 8 includes an exemplary actuator  14  mounted above the cylindrical valve chamber. A respective piston  50  resides in each of the three cylindrical valve chambers  16 ,  24 ,  38 . Each of the respective pistons  50  is movable to engage with and disengage from a respective valve seat  22 ,  30 ,  46  thereby allowing ports  20 ,  26 ,  36  to be opened and/or closed through actuation of pistons  50 . Each of the valve seats  22 ,  30 ,  46  is positioned in a respective end wall of the cylindrical valve chamber. The transition from cylindrical wall to end wall should be radiused to present a smooth curved surface  51  thereby avoiding potential bubble traps.  
         [0036]    Each actuator  14  is preferably a pneumatic or hydraulic type actuator as are well known in the art. Each actuator  14  includes a housing element  52  with a cover element  54 . Slidably residing in each housing element is a shaft  56 . Shaft  56  is generally coaxial with and connected to piston  50  such as by a mandrel extending from shaft  56  which threadably engages piston  50 . Affixed to shaft  56  is a drive piston  58 . Drive piston  58  can be driven up or down within housing element  52  by providing pneumatic or hydraulic pressure to either side of drive piston  58 . In such manner, each piston  50  can be driven into engagement with and disengagement from a respective valve seat  22 ,  30 ,  46 . There is a spring  60  in each housing element  52  normally biasing drive piston  58  and piston  50  away from a respective valve seat. As shown, each of pistons  50  preferably includes an elastomeric diaphragm  62  which permits piston  50  from being reciprocated within a cylindrical valve chamber between open and closed positions. Elastomeric diaphragm  62  includes a flange portion  64  which resides in annular recess  66 . Thus, elastomeric diaphragm  62  with flange portion  64  provides a seal between housing element  52  and the valve chamber  16 ,  24 ,  38 . Each respective valve actuator  14  is preferably independently controllable for actuating each of the three pistons  50 .  
         [0037]    To allow for the most efficient purging of bubbles from multiport valve  10 , it is preferable that multiport valve  10  be oriented such that the third outlet port  42  is substantially horizontal and tangentially intercepts the intermediate cylindrical valv3e chamber  38  at a top surface thereof. Further, it is preferable that multiport valve  10  be oriented such that the second outlet port  28  is located on the top surface of the valve body  12 . When so oriented, coating solutions always flow up through valve  10 .  
         [0038]    As discussed above, valve body  12  includes ports  18 ,  28 ,  32  and  42 . Such ports  18 ,  28 ,  32  and  42  are generically depicted in cross-section in FIG. 9 to show that they are preferably internally threaded. In such manner, valve body  12  includes for integrally formed fittings. The internally threaded portion of each port has a larger inside diameter than the inside diameter of the remainder of the port. When properly sized, the threaded conduit or nipple  70  engaged with the threaded portion of the port will have the same inside diameter as a non-threaded portion of the port. In this manner, crevices, large seams, and other discontinuities within the valve body that could undesirably trap air bubbles or residual composition are substantially eliminated. A washer or gasket  72 , formed preferably of an incompressible and generally non-reactive substance, resides between the threaded end of the conduit or nipple  70  and the step in the port created by the change in inside diameter from the threaded portion thereof to the non-threaded portion thereof. Washer or gasket  72  should have the same inside diameter as the conduit or nipple  70 . By way of example, silver is an excellent material for washer  72  when the valve is used with photographic emulsions.  
         [0039]    When used as a valve to supply both coating composition and flush water to coating apparatus, first inlet port  18  is preferably used for flush water inlet, primary liquid inlet port  32  is preferably used for coating composition inlet, second outlet port  28  is preferably used to go to drain, and third outlet port  42  is used for coating composition outlet from the valve  10  to the coating apparatus.  
         [0040]    The flow paths provided through valve  10  may be summarized as with reference to the schematic depiction of multiport valve  10  in FIG. 10. A liquid coating composition to be regulated by valve  10  enters valve body  12  via primary liquid inlet port  32  on the underside of valve body  12  and fills the internal conduit or passageway  34  leading to valve seats  30 ,  46  of second cylindrical valve chamber  28  and intermediate cylindrical valve chamber  16 , respectively. Preferably, the internal conduit or passageway  34  is as short as practically possible to minimize the length of dead leg inherent therein. Water entering valve body  10  via first water inlet port  18  fills first cylindrical valve chamber  16 . Water can be flowed from the water supply to the coating apparatus by actuating pistons  50  such that the piston in first cylindrical valve chamber  16  is in the open position and the piston and in the intermediate cylindrical valve chamber  38  is in the closed position. Coating composition can be flowed from coating composition supply to drain by actuating the pistons  50  such that the piston within intermediate cylindrical valve chamber  38  is in the closed position and the piston within second cylindrical valve chamber  24  is in the open position. Coating composition can be flowed from coating composition supply to the coating apparatus by actuating the pistons within second cylindrical valve chamber  24  and intermediate cylindrical valve chamber  38  such that the piston within second cylindrical valve chamber  24  is in the closed position and the piston within intermediate cylindrical valve chamber  38  is in the open position.  
         [0041]    As shown and described herein, coating solutions delivered to a coating apparatus via multiport valve  10  are not exposed to any threads. The process ports in valve body  12  are designed to allow a constant diameter through the valve to be maintained with the exception, of course, of the cylindrical valve chambers. The cylindrical valve chambers are designed to allow effective bubble purging. First inlet port  18  and third outlet port  42  tangentially intercept first cylindrical valve chamber  16  and intermediate cylindrical valve chamber  38 , respectively, to effectively eliminate any bubble traps in chambers  16 ,  38  and allowing bubbles to be swept from chambers  16 ,  38 .  
         [0042]    From the foregoing it will be seen that this invention is one well adapted to attain all of the ends and objects hereinabove set forth together with other advantages which are apparent and which are inherent to the process.  
         [0043]    It will be understood that certain features and subcombinations are of utility and may be employed with reference to other features and subcombinations. This is contemplated by and is within the scope of the claims.  
         [0044]    As many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth and shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.  
       Parts List  
       [0045]    [0045] 10  Muliport Valve  
         [0046]    [0046] 12  Valve Body  
         [0047]    [0047] 14  Actuators  
         [0048]    [0048] 16  First Cylindrical Valve Chamber  
         [0049]    [0049] 18  First Inlet Port  
         [0050]    [0050] 20  First Outlet Port  
         [0051]    [0051] 22  First Valve Seat  
         [0052]    [0052] 24  Second Cylindrical Chamber  
         [0053]    [0053] 26  Second Inlet Port  
         [0054]    [0054] 30  Second Valve seat  
         [0055]    [0055] 32  Primary Liquid Inlet Port  
         [0056]    [0056] 34  Internal Conduit  
         [0057]    [0057] 36  Alternative inlet port  
         [0058]    [0058] 38  Intermediate Cylindrical Valve Chamber  
         [0059]    [0059] 40  Third Inlet Port  
         [0060]    [0060] 42  Third Outlet Port  
         [0061]    [0061] 46  Third Valve Set  
         [0062]    [0062] 50  Piston  
         [0063]    [0063] 51  Smooth Curved Surface  
         [0064]    [0064] 52  Housing Element  
         [0065]    [0065] 54  Cover Element  
         [0066]    [0066] 56  Shaft  
         [0067]    [0067] 58  Drive Piston  
         [0068]    [0068] 60  Spring  
         [0069]    [0069] 62  Elastomeric Diaphragm  
         [0070]    [0070] 64  Flange Portion  
         [0071]    [0071] 66  Annular Recess  
         [0072]    [0072] 70  Threaded Conduit or Nipple  
         [0073]    [0073] 72  Washer or Gasket