Abstract:
A dispensing valve is provided for dispensing liquid from a cartridge. The valve includes a valve body that is adapted to receive at least a portion of the cartridge therein. A valve member is disposed in the valve body and is adapted for fluid communication with the cartridge. A valve seat element is disposed in the valve body and includes a liquid chamber that is in communication with the liquid outlet and is mounted for reciprocating movement between a closed position engaged with the valve member to prevent liquid from exiting the liquid outlet and an open position disengaged from the valve member to allow liquid to flow from the liquid chamber through the liquid outlet. The valve body may include a longitudinal axis and a receive bore extending along the longitudinal axis, with the liquid outlet being substantially co-axial with the receiving bore.

Description:
This application claims the priority of U.S. Provisional Patent Application Ser. No. 61/029,731, filed on Feb. 19, 2008, the disclosure of which is incorporated by reference herein. 
    
    
     TECHNICAL FIELD 
     This invention is related to apparatus and methods for dispensing liquids and, more particularly, to apparatus and methods for dispensing liquids from a cartridge. 
     BACKGROUND 
     In certain applications it is sometimes necessary to dispense liquids out of a cartridge or similar container and onto a desired target. For example, in the electronics industry, materials such as polyurethane reactive (“PUR”) adhesives may be dispensed out of a syringe-like cartridge and onto a desired target. Conventional apparatus for dispensing viscous liquids from cartridges may result in stringing of the liquid, and this can negatively affect quality and/or control of the dispensing operation. 
     There is a need, therefore, for apparatus and methods that address these and other issues associated with conventional apparatus and methods. 
     SUMMARY 
     In one embodiment, a dispensing valve includes a valve body that is adapted to receive at least a portion of the cartridge therein. A valve member is disposed in the valve body and is adapted for fluid communication with the cartridge. A valve seat element is disposed in the valve body. The valve seat element includes a liquid chamber with a liquid outlet and is mounted for reciprocating movement between a closed position engaged with the valve member to prevent liquid from exiting the liquid outlet and an open position disengaged from the valve member to allow liquid to flow from the liquid chamber through the liquid outlet. The valve body may include a longitudinal axis and a receiving bore extending along the longitudinal axis, with the liquid outlet being substantially co-axial with the receiving bore. Additionally or alternatively, the valve body may include a longitudinal axis and the valve seat element is mounted for reciprocating movement substantially along the longitudinal axis. 
     The valve body may include a luer connector that is adapted for coupling with the cartridge. The liquid outlet may be disposed in the valve seat element for movement therewith between the open and closed positions. At least one of the valve member or the valve seat element may be formed of a plastic material. The valve body may include an air inlet for receiving actuation air there through, with the valve seat element being in communication with the air inlet and being movable between the open and closed positions by action of the actuation air. The valve body may include a detachable distal portion, with removal of the detachable distal portion providing access to the valve seat element. 
     In another embodiment, an assembly is disclosed for dispensing liquid from a cartridge. The assembly includes a valve body that is adapted to receive at least a portion of the cartridge therein. A solenoid valve is coupled to the valve body and is in fluid communication therewith. A valve member is disposed in the valve body and is adapted for fluid communication with the cartridge. A valve seat element is disposed in the valve body and has opposed surfaces in communication with the solenoid valve and a liquid chamber with a liquid outlet. The valve seat element is mounted for reciprocating movement between a closed position engaged with the valve member to prevent liquid from exiting the liquid outlet and an open position disengaged from the valve member to allow liquid to flow from the liquid chamber through the liquid outlet. The reciprocating movement is effected by selective directing of actuation air from the solenoid valve against one of the opposed surfaces of the valve seat element. The valve body may include an actuation air inlet that is adapted for coupling with a source of air, with the actuation air inlet extending through the valve body and communicating with a solenoid air inlet for feeding of actuation air into the solenoid valve. 
     In yet another embodiment, a method of dispensing liquid from a cartridge supported within a bore of a valve body includes maintaining a valve member with a liquid flow passage fluidly coupled to the cartridge and substantially fixed relative to the valve body. A valve seat element reciprocates between open and closed positions respectively into engagement and out of engagement with the valve member to control flow of the liquid from the cartridge through the liquid flow passage and out of the valve body. The method may include coupling the valve member with the cartridge outside of the valve body prior to insertion of the cartridge into the bore of the valve body. Alternatively or additionally, the method may include pressurizing the liquid within the cartridge. The method may include heating the liquid in the cartridge through the valve body. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an assembly for dispensing a liquid out of a cartridge in accordance with one embodiment of the invention. 
         FIG. 2  is a view taken generally along line  2 - 2  of  FIG. 1 . 
         FIG. 2A  is a partially sectioned perspective view of a portion of the dispensing valve of  FIGS. 1 and 2 . 
         FIG. 2B  is a partially sectioned perspective view similar to  FIG. 2A  showing a valve seat element in an open position. 
         FIG. 3  is a perspective view of an exemplary cartridge. 
         FIG. 4  is a perspective translucent view of a portion of the dispensing valve of  FIGS. 1 and 2 . 
         FIG. 5  is a view taken generally along line  5 - 5  of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     With reference to the figures, and more particularly to  FIGS. 1-5 , a dispensing valve  10  is shown for dispensing a liquid  12  such as, and without limitation, polyurethane reactive (PUR) adhesive from a cartridge  14  containing such liquid  12 . A solenoid valve  11  is coupled to the valve  10  for selectively supplying actuation air to the valve  10 , as further explained below. Jointly, the valve  10  and solenoid valve  11  define an assembly  13  for dispensing the liquid  12  from cartridge  14 . The valve  10  includes a valve body  20  configured to receive at least a portion of the cartridge  14  therein to facilitate dispensing of the liquid  12  onto a target such as a schematically-depicted electronic component  22 . In this exemplary embodiment, valve  10  is configured for dispensing liquid  12  from an exemplary syringe-like cartridge  14  having a barrel  24  that defines a volume containing the liquid  12 . Barrel  24  extends between proximal and distal ends  26 ,  28  of cartridge  14  and includes a coupling portion for coupling the cartridge  14  with a cooperating feature of the valve  10 , as further discussed below. A cap  30  is disposed at the proximal end  26  of the cartridge  14  and blocks access to the liquid  12 . An orifice  32  in cap  30  permits injection of pressurized air there through to pressurize the interior  34  of barrel  24  and thereby facilitates dispensing of the liquid  12  through a dispensing aperture  36  at the distal end  28  of cartridge  14 . A gripping portion  40  of cartridge  14  facilitates manipulation thereof into and out of a receiving bore  50  of the valve  10  and further facilitates control of the distal placement of the cartridge  14  within valve body  20 . 
     As discussed, above, valve  10  receives at least a portion of the cartridge  14  therein. In this exemplary embodiment, the receiving bore  50  extends generally along a longitudinal axis  52  of valve body  20  and is suitably shaped and sized to receive the exemplary cartridge  14  of  FIG. 3  therein. The receiving bore  50  extends between proximal and distal ends  60 ,  62  of valve body  20  and includes, in this embodiment, a tapered section  64  that facilitates closely receiving barrel  24  of cartridge  14  within valve body  20 . Moreover, in this embodiment, the receiving bore  50  includes a coupling portion in the shape of a luer connector  66  ( FIG. 2A ) that cooperates with a luer coupling element  68  ( FIG. 3 ) of cartridge  14  to secure or at least conform cartridge  14  and valve  10  relative to one another. 
     The luer connector  66  in this exemplary embodiment may include threads (not shown) that engage cooperating threads (not shown) on luer coupling element  68  of the cartridge  14  to thereby secure the cartridge  14  and valve body  20  relative to one another. Those of ordinary skill in the art will readily appreciate that valve  10  may alternatively include a different type of connector or coupling element or no such structure at all. 
     With continued reference to  FIGS. 1-5 , a clasp  70  of the valve  10  is coupled to the proximal end  60  of the valve body  20  and is rotatable into and out of engagement with cartridge  14 , to thereby secure cartridge  14  relative to valve body  20 . More particularly, clasp  70  is rotatable about a reference axis  21  ( FIG. 5 ) defined by a bolt  23  or similar structure, into engagement with the cap  30  of cartridge  14  and is secured in place relative to valve body  20  via one or more fasteners, for example. In this particular embodiment, once rotated into engagement with cap  30 , clasp  70  is secured in place by a bolt or screw  74  ( FIG. 1 ) and a cooperating secondary fastener such as a set screw  75  that frictionally engages bolt or screw  74 . It is contemplated that other mechanisms including or obviating fasteners may substitute the fasteners above described to permit clasp  70  or another similar structure to secure cartridge  14  relative to valve body  20 . Likewise, it is contemplated that such structure may engage other portions of the cartridge  14  such as, and without limitation, the gripping portion  40 . 
     End surfaces  77 ,  78  of valve body  20  accommodate gripping portion  40  of cartridge  14  and thereby facilitate limiting of the distal placement (along longitudinal axis  52 ) of cartridge  14  within valve body  20 . An air conduit  80  is adjacent clasp  70  and extends through orifice  32  of cap  30  to communicate with the interior  34  of barrel  24 . Air conduit  80  permits coupling of an air source (not shown) to pressurize the interior of barrel  24  and thus facilitate dispensing of liquid  12 . To this end, in this embodiment, the exemplary air conduit  80  may include a recess  82  that permits relatively quick coupling of the air source (not shown) with air conduit  80 . 
     In this exemplary embodiment, valve body  20  is defined by a distal portion  90  and a main portion  92  coupled to one another, for example, via fasteners (not shown). This two-part construction of valve body  20  permits, if desired, separation of the portions  90 ,  92  for cleaning or replacement purposes, for example. 
     As discussed above, valve  10  is configured to dispense liquid  12  from cartridge  14 . To this end, a valve member  100  and a cooperating valve seat element  102  are disposed in distal portion  90  to dispense liquid  12  through a liquid outlet  110  of valve body  20 , as explained in further detail below. In operation, the valve member  100  may be pre-coupled to the cartridge  14  outside of valve  10  and then inserted through an opening into bore  50  at proximal end  60 . Valve member  100  may be made of any suitable material. For example, and without limitation, valve member  100  may be formed of a plastic material which may also facilitate disposability thereof. The valve seat element  102  may be inserted into valve body  20  through an opening  97  at distal end  62  and secured to valve body  20  via a detachable portion  103 . In this exemplary embodiment, detachable portion  103  is in the form of a nut that threadably engages an inner wall  105  of valve body  20 , although other forms of detachable portions are contemplated so long as they provide access to an interior of valve body  20  and, more particularly, access to valve seat element  102 . Such access may be desirable for cleaning or replacement of valve seat element  102  which may be further made of a plastic material to thereby facilitate disposability thereof. 
     With continued reference to  FIGS. 1-5 , the exemplary valve member  100  is a needle-like elongated structure extending generally from the coupling portion  66  of receiving bore  50  and includes a generally L-shaped passage  116  that is in fluid communication with dispensing aperture  36  of cartridge  14  to receive liquid  12  from cartridge  14 . Valve member  100  has a generally fixed position relative to valve body  20  and is generally surrounded by valve seat element  102 . Valve seat element  102  is movable relative to valve body  20  and thus movable relative to valve member  100 . A volume between valve member  100  and valve seat element  102  defines a chamber  104  that fills up with liquid  12  that flows out of passage  116 . Detachable portion  103  surrounds a distal portion of valve seat element  102  and restricts distal movement thereof. Valve seat element  102  reciprocates generally in a direction along or parallel to longitudinal axis  52  between an open position and a closed position. In this regard, valve member  100  includes a contacting surface  120  that engages a proximal entrance  122  into liquid outlet  110  when valve seat element  102  is in the closed position. When valve seat element  102  is in the open position, a gap  126  is defined between contacting surface  120  and proximal entrance  122 , thereby permitting flow of liquid  12  therethrough. More particularly, when in the open position, gap  126  permits flow of liquid  12  from chamber  104  and through liquid outlet  110 , thereby allowing dispensing of liquid  12  out of valve  10  and onto the target (e.g., electronic component  22 ). 
     Reciprocating movement of valve seat element  102  results in a corresponding reciprocating movement of liquid outlet  110  toward and away from the target. Moreover, the geometric disposition of the different components described above relative to the cartridge  14  facilitates a relative short path for the liquid  12  to travel as it exits dispensing aperture  36  and leaves valve  10  through liquid outlet  110 , which in this embodiment is substantially coaxial with receiving bore  50 . 
     With continued reference to  FIGS. 1-5 , reciprocating movement of the valve seat element  102  is, in this exemplary embodiment, facilitated by pneumatic components. In particular, an actuation air inlet  130  extends from a peripheral surface  132  of detachable portion  90  and into the valve body  20  to facilitate such reciprocating movement. Inlet  130  communicates with an air feed passage  133  that, in turn, feeds actuation air into the solenoid valve  11  ( FIG. 1 ) through a solenoid air inlet  11   a  of solenoid valve  11 . Solenoid valve  11  selectively directs actuation air into valve body  20  through upper and lower actuation air passages  135 ,  137  disposed within valve body  20 . As used herein, the terms “upper,” “lower,” “up,” and “down” and derivatives thereof are not meant to be limiting but rather refer to the illustrative orientations shown in  FIGS. 1-5 . Upper actuation air passage  135  communicates with a volume defined above an upper surface  139  of valve seat element  102 . Lower actuation air passage  137  communicates with a lower surface  141  of valve seat element  102  which is disposed axially opposite from upper surface  139 . When the solenoid valve  11  directs air through the upper actuation air passage  135 , actuation air pushes down on upper surface  139 , thereby causing downward movement of valve seat element  102 . This movement, as discussed above, disengages valve seat element  102  from valve member  100 , thereby permitting flow of liquid  12  through liquid outlet  110 . Conversely, when the solenoid valve  11  directs air through the lower actuation air passage  137 , actuation air pushes up on lower surface  141 , thereby causing upward movement of valve seat element  102 . This movement engages valve seat element  102  with valve member  100 , thereby restricting flow of liquid  12  through liquid outlet  110 . 
     While this embodiment illustrates actuation through a solenoid valve  11  that selectively directs actuation air to two separate regions of the valve body  20 , those of ordinary skill in the art will readily appreciate that other actuation components and processes may be used instead. For example, and without limitation, actuation may be effected through the combination of air and one or more springs or other biasing elements. Likewise, actuation may be effected through electromagnetic components rather than or in combination with pneumatic and/or mechanical components. Moreover, in the exemplary embodiment of  FIG. 1-5 , sealing elements restrict passage of air and/or liquid between different components of valve  10 . These sealing elements are in the form of o-rings  140  of types and materials known in the art. In this regard, those of ordinary skill in the art will readily appreciate that other types of sealing elements or no sealing elements at all may be used instead. 
     In some applications it may be desirable to heat the contents of the cartridge  14  while in valve body  20 . To this end, a heater box portion  150  of valve body  20  extends along a length of valve body  20  to contain heating components that provide heat to cartridge  14 . In particular, heater box portion  150  includes a bore  154  that is adapted to receive a heating element (not shown) therein. A chamber  156  in heater box portion  150  is adapted to hold wires (not shown) connecting the heating element to a power source (not shown). In this illustrative embodiment, which includes no heating element, a cover  160  blocks access to an interior of heater box portion δ  50  and is secured in place via exemplary screws  170 . 
     With continued reference to  FIGS. 1-5 , the valve body  20  may be coupled to a surrounding structure (not shown) via a mounting block  180  that is spaced from valve body  20  via one or more thermal insulating spacers  188  that reduce the transfer of heat between valve  10  and surrounding structures. This mounting block  180  is merely exemplary and may be replaced by any other type of suitably located mounting structure or no mounting structure at all. 
     While the present invention has been illustrated by the description of specific embodiments thereof, and while the embodiments have been described in considerable detail, it is not intended to restrict or in any way limit the scope of the appended claims to such detail. The various features discussed herein may be used alone or in any combination. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and methods and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the scope or spirit of the general inventive concept.