Abstract:
A manual pump dispenser includes a plunger head reciprocable between pressure and return strokes, and a pump body having an inlet valve for inletting of liquid product during each of the return strokes. A discharge valve assembly is fitted to a spout for permitting selective outletting of liquid product through the spout during each of the pressure strokes. The spout includes a bore having a predetermined diameter, with a unitary valve disposed substantially within the bore. The unitary valve is made of a material for permitting predetermined axial, or axial and radial expansion thereof under pressure from liquid product during each of the pressure strokes for thereby allowing liquid product to be discharged through a slitted opening in the unitary valve, and enabling rapid contraction thereof against a valve seat to prevent liquid product from being discharged through the slitted opening.

Description:
BACKGROUND OF INVENTION 
   a. Field of Invention 
   The invention relates generally to a manually actuated pump dispenser having an improved discharge valve member, and more particularly to such a valve member of elastomeric material capable of a quick shut-off of the discharge and having a slitted valve element for discharging personal use products such as hand lotions or the like. 
   b. Description of Related Art 
   The known manually actuated pump dispensers especially those designed for the dispensing of hand lotions, body lotions, liquid soaps, and other viscous products, typically have both inlet and outlet ball check valves for respectively controlling the flow of liquid product into the pump chamber on each piston suction stroke and for controlling the outflow of the liquid product from the pump chamber during each piston compression stroke. Alternatively, such dispensers may include an inlet ball check valve for controlling the flow of liquid product into the pump chamber and a deformable outlet valve disposed adjacent a discharge end of the spout. U.S. Pat. No. 5,447,258 (hereinafter “the &#39;258 Patent”) is exemplary of such a known pump dispenser. 
   Specifically, as illustrated in FIGS. 2-5 of the &#39;258 Patent, for the conventional spout as therein disclosed, the end of the spout includes a transverse hole 134 covered by an expandable/stretchable cap 135 having an internal annular bead seated within an external annular groove on the spout for maintaining the cap in place (FIG. 2). A discharge opening 136 is located in an end wall of the cap through which product is discharged upon operation of the pump as product flows through both the axial discharge passage 130 of the spout and through transverse hole 134. In order to more securely attach cap 135 in place, a fixed ring 137 is provided in the FIGS. 3, 4 embodiment or a fixed ring 237 is provided for the FIG. 5 embodiment. 
   The deformable outlet valve (i.e. cap 135) disclosed in FIGS. 2-5 of the &#39;258 Patent is problematic in many respects, in that cap 135 will simply dislodge from the end of the spout upon application of even slight pressure applied through axial passage 130 and transverse hole 134. This is tacitly recognized as the FIGS. 3 to 5 embodiments require a fixed ring 137 or 237 to maintain cap 135 securely mounted in place at the end of the spout. However, the provision of the extra fixed ring 137 or 237 requires an extra part for securing cap 135 during manufacture of the pump dispenser, and further increases the likelihood of the dispenser failing due to dislodgement of cap 135 during repeated pumping operation. 
   It would therefore be of benefit to provide a pump dispenser including an improved deformable outlet valve which both facilitates assembly of the pump dispenser, and which is securely disposed at an end of the dispenser spout for reducing or virtually eliminating the odds of the valve being dislodged from the spout. 
   Yet further, as illustrated in FIG. 1 of the &#39;258 Patent, there is disclosed an improved outlet valve assembly including first and second valve bodies 7, 11, respectively. For the dispenser of FIG. 1, as fluid passes from pipe 2 into hole 5, second valve body 11, which is made of flexible synthetic resin, deforms outwardly to discharge the contents of pipe 2 therethrough and thereafter should return to its rest configuration illustrated in FIG. 1. 
   As discussed above for cap 135 disclosed in FIGS. 2-5 of the &#39;258 Patent, the valve assembly disclosed in FIG. 1 of the &#39;258 Patent is also problematic in many respects, in that after repeated use, the interaction of product against the inner walls of body 11 and product remaining between shaft 6 and body 11 increases the time it takes for body 11 to close around shaft 6 and thereby prevent further product from being discharged. The interaction of product against the inner walls of body 11 can eventually cause the structure forming body 11 to remain in an outwardly deformed configuration. This condition deteriorates the cross-sectional quality of the discharged product, which at the initial use of the dispenser mechanism, is intended to have a predetermined cross-section designed to be ergonomically pleasing to the user and/or designed for a specific end use. Further, the valve assembly disclosed in FIG. 1 of the &#39;258 Patent includes at least three components fitted together for adequate operation, namely first and second valve bodies 7, 11, respectively, and stopper 22, which render the design thereof complex with regard to the manufacture thereof, and which further increase the odds of failure of one or more of the components. 
   It would therefore be of benefit to provide a pump dispenser having an improved deformable outlet valve which both facilitates easier and more economical manufacture and assembly of the pump dispenser, which provides repeatability in the cross-sectional quality of the discharged product over the life of the pump dispenser, and which is robust in design and efficient to operate. It would also be of benefit to provide a pump dispenser which will quickly respond for sealing the discharge flow path during each piston suction stroke irrespective of the viscosity of the product being dispensed. 
   SUMMARY OF INVENTION 
   The invention solves the problems and overcomes the drawbacks and deficiencies of prior art pump dispenser designs by providing in combination an improved deformable outlet valve which both facilitates manufacture and assembly of the pump dispenser, and which provides repeatability in the cross-sectional quality of the discharged product over the life of the pump dispenser. 
   The present invention thus provides a manual pump dispenser including a plunger head reciprocable between pressure and return strokes. The pump dispenser may include a pump body having an inlet valve for inletting of a liquid product into the pump dispenser during each of the return strokes, and a discharge valve assembly fitted to a spout provided with the pump body. The discharge valve assembly may permit selective outletting of the liquid product through the spout during each of the pressure strokes. The spout may include a bore having a predetermined diameter. The discharge valve assembly may include a unitary valve disposed substantially within the bore, the unitary valve having an outer diameter smaller than the predetermined diameter. The unitary valve may be made of a material for permitting predetermined axial and radial expansion of the unitary valve under pressure from the liquid product during each of the pressure strokes for thereby allowing the liquid product to be discharged out through a slitted opening at an outlet end of the unitary valve, and enabling rapid contraction of the unitary valve against a valve seat to prevent the liquid product from being discharged through the slitted opening. 
   For the pump dispenser described above, the unitary valve may include a plurality of slitted openings oriented such that the liquid product discharged therethrough includes a substantially star-shaped cross-section. The pump dispenser may further include a valve adaptor with the unitary valve being coupled to the valve adaptor for retaining the unitary valve within the spout. The valve adaptor and the unitary valve may be coupled together by the provision of an annular groove and an annular rib, or an annular rib and an annular wall. The valve adaptor may include an axial channel for passage of the liquid product from an upstream end of the spout toward the slitted opening. The valve adaptor may include a plurality of lateral passageways fluidly coupled with the axial channel for enabling uniform distribution of the liquid product from the upstream end of the spout toward the slitted opening. The valve seat may be formed integrally with the valve adaptor. The unitary valve may be formed of a silicone and/or a thermoplastic elastomer, and may be expandable within the bore. The unitary valve may primarily be radially contractible against a circumferential surface of the valve seat to prevent the liquid product from being discharged through the slitted opening. The unitary valve may include a generally cylindrical profile in its contracted configuration. The unitary valve may alternatively be axially and radially contractible against respective frontal and circumferential surfaces of the valve seat to prevent the liquid product from being discharged through the slitted opening. The unitary valve may also alternatively include a generally frusto-conical profile in its contracted configuration. 
   The invention yet further provides a plunger head for a manually actuated pump dispenser, being reciprocable between pressure and return strokes, and including a discharge spout. The plunger head may include a pump body having an inlet valve for inletting of a liquid product into the pump dispenser during each of the return strokes. A discharge valve assembly may be fitted to the spout for permitting selective outletting of the liquid product through the spout during each of the pressure strokes. The spout may include a bore having a predetermined diameter. The discharge valve assembly may include an outlet valve disposed substantially within the bore. The outlet valve may include an outer diameter smaller than the predetermined diameter. The outlet valve may be made of a material for permitting predetermined axial and radial expansion of the outlet valve under pressure from the liquid product during each of the pressure strokes for thereby allowing the liquid product to be discharged out through a slitted opening at an outlet end of the outlet valve, and enabling rapid contraction of the outlet valve against a valve seat to prevent the liquid product from being discharged through the slitted opening. 
   For the plunger head described above, the outlet valve may include a plurality of slitted openings oriented such that the liquid product discharged therethrough includes a substantially star-shaped cross-section. The plunger head may further include a valve adaptor with the outlet valve being coupled to the valve adaptor for retaining the outlet valve within the spout. The valve adaptor and the outlet valve may be coupled together by the provision of an annular groove and an annular rib, or an annular rib and an annular wall. The valve adaptor may include an axial channel for passage of the liquid product from an upstream end of the spout toward the slitted opening. The valve adaptor may include a plurality of lateral passageways fluidly coupled with the axial channel for enabling uniform distribution of the liquid product from the upstream end of the spout toward the slitted opening. The valve seat may be formed integrally with the valve adaptor. The outlet valve may be formed of a silicone and/or a thermoplastic elastomer, and may be expandable within the bore. The outlet valve may primarily be radially contractible against a circumferential surface of the valve seat to prevent the liquid product from being discharged through the slitted opening. The outlet valve may include a generally cylindrical profile in its contracted configuration. The outlet valve may alternatively be axially and radially contractible against respective frontal and circumferential surfaces of the valve seat to prevent the liquid product from being discharged through the slitted opening. The outlet valve may also alternatively include a generally frusto-conical profile in its contracted configuration. 
   The invention yet further provides a discharge spout including an inlet end for inletting of a liquid product. A discharge valve assembly may be fitted to the spout for permitting selective outletting of the liquid product through the spout. The spout may include a bore having a predetermined diameter. The discharge valve assembly may include an outlet valve disposed substantially within the bore. The outlet valve may have an outer diameter smaller than the predetermined diameter. The outlet valve may be made of a material for permitting predetermined axial and radial expansion of the outlet valve when under pressure from the liquid product for thereby allowing the liquid product to be discharged out through a slitted opening at an outlet end of the outlet valve, and enabling rapid contraction of the outlet valve against a valve seat to prevent the liquid product from being discharged through the slitted opening. 
   For the discharge spout described above, the outlet valve may include a plurality of slitted openings oriented such that the liquid product discharged therethrough includes a substantially star-shaped cross-section. The discharge spout may further include a valve adaptor with the outlet valve being coupled to the valve adaptor for retaining the outlet valve within the spout. The valve adaptor and the outlet valve may be coupled together by the provision of an annular groove and an annular rib, or an annular rib and an annular wall. The valve adaptor may include an axial channel for passage of the liquid product from an upstream end of the spout toward the slitted opening. The valve adaptor may include a plurality of lateral passageways fluidly coupled with the axial channel for enabling uniform distribution of the liquid product from the upstream end of the spout toward the slitted opening. The valve seat may be formed integrally with the valve adaptor. The outlet valve may be formed of a silicone and/or a thermoplastic elastomer, and may be expandable within the bore. The outlet valve may primarily be radially contractible against a circumferential surface of the valve seat to prevent the liquid product from being discharged through the slitted opening. The outlet valve may include a generally cylindrical profile in its contracted configuration. The outlet valve may alternatively be axially and radially contractible against respective frontal and circumferential surfaces of the valve seat to prevent the liquid product from being discharged through the slitted opening. The outlet valve may also alternatively include a generally frusto-conical profile in its contracted configuration. 
   The invention further provides a manual pump dispenser including a plunger head reciprocable between pressure and return strokes. The pump dispenser may include a pump body having an inlet valve for inletting of a liquid product into the pump dispenser during each of the return strokes. A discharge valve assembly may be fitted to a spout provided with the pump body. The discharge valve assembly may permit selective outletting of the liquid product through the spout during each of the pressure strokes. The spout may include a bore having a predetermined diameter. The discharge valve assembly may include a unitary valve disposed substantially within the bore. The unitary valve may have an outer diameter generally equal to the predetermined diameter. The unitary valve may be made of a material for permitting primarily predetermined axial expansion of the unitary valve under pressure from the liquid product during each of the pressure strokes for thereby allowing the liquid product to be discharged out through a slitted opening at an outlet end of the unitary valve, and enabling rapid axial contraction of the unitary valve against a valve seat to prevent the liquid product from being discharged through the slitted opening. 
   For the pump dispenser described above, the unitary valve may include a plurality of slitted openings oriented such that the liquid product discharged therethrough includes a substantially star-shaped cross-section. The pump dispenser may further include a valve adaptor with the unitary valve being coupled to the valve adaptor for retaining the unitary valve within the spout. The valve adaptor and the unitary valve may be coupled together by the provision of an annular groove and an annular rib, or an annular rib and an annular wall. The valve adaptor may include an axial channel for passage of the liquid product from an upstream end of the spout toward the slitted opening. The valve adaptor may include a plurality of lateral passageways fluidly coupled with the axial channel for enabling uniform distribution of the liquid product from the upstream end of the spout toward the slitted opening. The valve seat may be formed integrally with the valve adaptor. The unitary valve may be formed of a silicone and/or a thermoplastic elastomer, and may be axially expandable outwardly from the bore. The unitary valve may be primarily axially contractible against a frontal surface of the valve seat to prevent the liquid product from being discharged through the slitted opening. The unitary valve may include a generally cylindrical profile in its contracted configuration, and a frontal surface of the unitary valve may be substantially thicker than a side wall of the unitary valve. 
   The invention yet further provides a plunger head for a manually actuated pump dispenser, the plunger head being reciprocable between pressure and return strokes and including a discharge spout. The plunger head may include a pump body having an inlet valve for inletting of a liquid product into the pump dispenser during each of the return strokes. A discharge valve assembly may be fitted to the spout for permitting selective outletting of the liquid product through the spout during each of the pressure strokes. The spout may include a bore having a predetermined diameter. The discharge valve assembly may include an outlet valve disposed substantially within the bore, the outlet valve may have an outer diameter generally equal to the predetermined diameter. The outlet valve may be made of a material for permitting primarily predetermined axial expansion of the outlet valve under pressure from the liquid product during each of the pressure strokes for thereby allowing the liquid product to be discharged out through a slitted opening at an outlet end of the outlet valve, and enabling rapid axial contraction of the outlet valve against a valve seat to prevent the liquid product from being discharged through the slitted opening. 
   For the plunger head described above, the outlet valve may include a plurality of slitted openings oriented such that the liquid product discharged therethrough includes a substantially star-shaped cross-section. The plunger head may further include a valve adaptor with the outlet valve being coupled to the valve adaptor for retaining the outlet valve within the spout. The valve adaptor and the outlet valve may be coupled together by the provision of an annular groove and an annular rib, or an annular rib and an annular wall. The valve adaptor may include an axial channel for passage of the liquid product from an upstream end of the spout toward the slitted opening. The valve adaptor may include a plurality of lateral passageways fluidly coupled with the axial channel for enabling uniform distribution of the liquid product from the upstream end of the spout toward the slitted opening. The valve seat may be formed integrally with the valve adaptor. The outlet valve may be formed of a silicone and/or a thermoplastic elastomer, and may be axially expandable outwardly from the bore. The outlet valve may be primarily axially contractible against a frontal surface of the valve seat to prevent the liquid product from being discharged through the slitted opening. The outlet valve may include a generally cylindrical profile in its contracted configuration, and a frontal surface of the outlet valve may be substantially thicker than a side wall of the outlet valve. 
   The invention also provides a discharge spout including an inlet end for inletting of a liquid product. A discharge valve assembly may be fitted to the spout for permitting selective outletting of the liquid product through the spout. The spout may include a bore having a predetermined diameter. The discharge valve assembly may include an outlet valve disposed substantially within the bore. The outlet valve may have an outer diameter generally equal to the predetermined diameter. The outlet valve may be made of a material for permitting primarily predetermined axial expansion of the outlet valve when under pressure from the liquid product for thereby allowing the liquid product to be discharged out through a slitted opening at an outlet end of the outlet valve, and enabling rapid axial contraction of the outlet valve against a valve seat to prevent the liquid product from being discharged through the slitted opening. 
   For the discharge spout described above, the outlet valve may include a plurality of slitted openings oriented such that the liquid product discharged therethrough includes a substantially star-shaped cross-section. The discharge spout may further include a valve adaptor with the outlet valve being coupled to the valve adaptor for retaining the outlet valve within the spout. The valve adaptor and the outlet valve may be coupled together by the provision of an annular groove and an annular rib, or an annular rib and an annular wall. The valve adaptor may include an axial channel for passage of the liquid product from an upstream end of the spout toward the slitted opening. The valve adaptor may include a plurality of lateral passageways fluidly coupled with the axial channel for enabling uniform distribution of the liquid product from the upstream end of the spout toward the slitted opening. The valve seat may be formed integrally with the valve adaptor. The outlet valve may be formed of a silicone and/or a thermoplastic elastomer, and may be axially expandable outwardly from the bore. The outlet valve may be primarily axially contractible against a frontal surface of the valve seat to prevent the liquid product from being discharged through the slitted opening. The outlet valve may include a generally cylindrical profile in its contracted configuration, and a frontal surface of the outlet valve may be substantially thicker than a side wall of the outlet valve. 
   Additional features, advantages, and embodiments of the invention may be set forth or apparent from consideration of the following detailed description, drawings, and claims. Moreover, it is to be understood that both the foregoing summary of the invention and the following detailed description are exemplary and intended to provide further explanation without limiting the scope of the invention as claimed. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate preferred embodiments of the invention and together with the detail description serve to explain the principles of the invention. In the drawings: 
       FIG. 1  is a side elevation view of a pump dispenser, partly broken away, according to the present invention, illustrating the various internal features of a first embodiment of the discharge valve assembly and the elastomeric discharge valve in a rest configuration; 
       FIG. 2  is a cross-sectional view of the discharge valve assembly of  FIG. 1 , taken substantially along line  2 - 2 , illustrating the star-shaped valve outlet; 
       FIG. 3  is a partial side elevation view of the pump dispenser spout of  FIG. 1 , illustrating the first embodiment of the elastomeric discharge valve in a deformed discharge open configuration during pumping; 
       FIG. 4  is a cross-sectional view of the first embodiment of the discharge valve assembly of  FIG. 1 , taken substantially along line  4 - 4 , illustrating the layout of the lateral passages; 
       FIG. 5  is a side elevation view of a pump dispenser, partly broken away, according to the present invention, illustrating the various internal features of a second embodiment of the discharge valve assembly and the elastomeric discharge valve in a rest configuration; 
       FIG. 6  is a view of the discharge valve assembly of  FIG. 5 , taken substantially along line  6 - 6 , illustrating the star-shaped valve outlet; 
       FIG. 7  is a partial side elevation view of the pump dispenser spout of  FIG. 5 , illustrating the second embodiment of the elastomeric discharge valve in a deformed discharge open configuration during pumping; 
       FIG. 8  is a cross-sectional view of the second embodiment of the discharge valve assembly of  FIG. 5 , taken substantially along line  8 - 8 , illustrating the layout of the lateral passages; 
       FIG. 9  is a side elevation view of a pump dispenser, partly broken away, according to the present invention, illustrating the various internal features of a third embodiment of the discharge valve assembly and the elastomeric discharge valve in a rest configuration; 
       FIG. 10  is a view of the discharge valve assembly of  FIG. 9 , taken substantially along line  10 - 10 , illustrating the star-shaped valve outlet; 
       FIG. 11  is a partial side elevation view of the pump dispenser spout of  FIG. 9 , illustrating the third embodiment of the elastomeric discharge valve in a deformed discharge open configuration during pumping; and 
       FIG. 12  is a cross-sectional view of the third embodiment of the discharge valve assembly of  FIG. 9 , taken substantially along line  12 - 12 , illustrating the layout of the lateral passages. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring now to the drawings wherein like reference numerals designate like and corresponding parts throughout the several views,  FIGS. 1-4  illustrate a first embodiment of a pump dispenser according to the present invention, generally designated  10 . 
   As shown in  FIG. 1 , a manually operated pump dispenser  10  of a type which incorporates discharge valve assembly  12  according to the invention comprises a pump body which includes a pump cylinder (not shown) adapted to be affixed to a container (not shown) of product to be dispensed in a conventional manner, as described in detail in U.S. patent application Ser. No. 10/214,160, titled “Pump Dispenser Having an Improved Discharge Valve,” owned by the Assignee of the present invention, and the disclosure of which is incorporated herein by reference. As also described in detail in U.S. patent application Ser. No. 10/214,160, the pump cylinder may be adapted to be affixed to a container by means of a closure cap which may be internally threaded or which may be adapted for snap fit engagement with the container neck in any normal manner. The cylinder may suspend a dip tube (not shown) at its lower end which extends into the liquid in the container. Although discharge valve assemblies  12 ,  102  and  202  (described below) for the first through third embodiments, respectively, have been described as being used in addition to a separate discharge valve provided within pump dispenser assemblies  10 ,  100  and  200  (described below), respectively, assemblies  12 ,  102  and  202  may be readily used in addition to or in lieu of a separate discharge valve provided within pump dispensers  10 ,  100  and  200 , as would be apparent to those skilled in the art. 
   Pump dispenser  10  may further include a depending sleeve  14  for mounting plunger head  16  to an upper end of hollow piston stem  18  of a piston having at its lower end an annular piston seal (not shown) in sliding sealing engagement with the inner wall of the pump cylinder, as also described in detail in U.S. patent application Ser. No. 10/214,160. Plunger head  16  may include a depending sleeve  20  which frictionally engages the upper end of piston stem  18  to effect a tight seal, and an elongated transverse spout  22  defining a discharge passage  24  which directly communicates with the upper end of the piston stem. 
   Referring to  FIGS. 1 and 3 , discharge valve assembly  12  according to the present invention comprises a unitary valve  26  of resilient material such as a silicone or thermoplastic elastomer of various durometers. Valve  26  may be supported by valve adaptor  28  disposed at a distal end of spout  22 , as described in greater detail below. Valve adaptor  28  may include an axial passage  30  which terminates in at least a pair of lateral passageways  32  with six such passageways  32  as illustrated in  FIG. 4 . Valve adaptor  28  may be frictionally or otherwise adhesively retained within bore  34  of spout  22 . 
   As illustrated in  FIGS. 1 and 3 , spout  22  may include a further bore  36  at a distal end thereof such that bore  36  is slightly greater in diameter than bore  34  so as to provide a stop means at annular wall  38  for enabling a predetermined depth of insertion of valve adaptor  28  into bore  34  by engagement of annular rib  40  against complementary annular wall  38 . An annular groove  42  may be provided along the outer circumference of valve adaptor  28  for facilitating engagement and retention of valve  26  with valve adaptor  28  by means of annular ring  44  of valve  26  being disposed in annular groove  42 . The inner diameter of bore  36  in which valve  26  is seated may be slightly greater than the outer diameter of valve  26  to permit expansion of valve  26  upon the discharge of pressurized product through lateral passageways  32 , as discussed in greater detail below. 
   Referring to  FIGS. 1-3 , in the particular embodiment illustrated, valve  26  may include a star-shaped (or other, i.e. triangular, circular, rectangular etc.) configuration defined by outlet slits  46 , which in the embodiment of  FIG. 2 , may include six such outlet slits  46  formed integrally with circular skirt wall  48  of valve  26 . Slits  46  may be defined as gaps between generally pie-shaped walls  50 , which function to guide product through the adjacently disposed slits  46 . It should be noted that instead of outlet slits  46 , valve  26  may include a molded exit area (not shown), as would be apparent to those skilled in the art. Valve  26  may further include a central conical outlet  52  provided within protrusion  54  disposed at the central end of pie-shaped walls  50 . While a small amount of product may be discharged through outlet  52 , protrusion  54  primarily functions to maintain walls  50  at the predetermined orientation illustrated in  FIG. 2 . 
   In order for product to be discharged through valve  26  during the downward stroke of plunger head  16 , for the orientation of slits  46  illustrated in  FIG. 2 , product discharged via spout  22  through valve  26  may first enter axial passage  30  of valve adaptor  28 , as illustrated by flow-paths A 1  and A 2 . Thereafter, product in axial passage  30  may generally uniformly enter lateral passageways  32  and divide into six flow-paths within the lateral passageways  32 , as illustrated by flow-path A 3 . As pressure from the product in lateral passageways  32  continues to increase during the downward stroke of plunger head  16  and reaches a predetermined threshold, further increase of pressure from the product during the continuing downward stroke of plunger head  16  deforms and expands outer circular skirt wall  48  of valve  26  radially and walls  50  axially outwardly to permit product to pass by circular deflector  56 , as illustrated by flow-path A 4 , and thereafter continue onwards and out through outlet slits  46 , as illustrated by flow-path A 5 . While the majority of product may exit through outlet slits  46  via flow-path A 5 , some of the product may travel radially inwards towards outlet  52  via flow-path A 6 , and then exit out through outlet  52  via flow-path A 7 . 
   When manual pressure applied to plunger head  16  is released or is interrupted, the pressure of product in area  58  decreases below the aforementioned predetermined threshold, such that walls  50  and circular wall  48  of valve  26  quickly contract respectively axially and radially inwardly to reach their rest configuration, illustrated in  FIGS. 1 and 3 . Thus, at the end of a given downward stroke of the plunger head, just prior to the ensuing plunger up stroke, circular skirt wall  48  of valve  26  quickly contracts inwardly (i.e. relaxes) to prevent any further product from being discharged through outlet slits  46  of valve  26 , and thereby closes outlet slits  46  by closing against lateral passageways  32  by the interaction of circular skirt wall  48  of valve  26  with the outer wall of circular deflector  56  formed integrally with valve adaptor  28 . 
   With the flow of product from spout  22  through valve  26  via flow-paths A 1 -A 7 , the product output through valve  26  has a consistently uniform star-shaped cross-section by means of the sections of product output through outlet slits  46  and uniformly joined by outlet  52 . Moreover, since the valve assembly according to the present invention includes only two components, namely valve adaptor  28  and unitary valve  26 , the reduced number of components facilitates easy and economical manufacture and assembly of the pump dispenser, while providing repeatability in the cross-sectional quality of the discharged product over the life of the pump dispenser. Moreover, the efficient operation of unitary valve  26  provides a pump dispenser which will quickly respond for sealing the discharge flow path during each piston suction stroke irrespective of the viscosity of the product being dispensed. Additionally, since bore  36  is configured to control and limit the expansion of valve  26  disposed therein, this configuration prevents valve  26  from remaining in an expanded configuration (as is the case with conventional valve designs) during continued use of pump dispenser  10  due to dried or other viscous product remaining between circular skirt wall  48  and circular deflector  56 . 
   The second embodiment of pump dispenser  100  will now be described in detail with reference to  FIGS. 5-8 . 
   As shown in  FIG. 5 , in a similar manner as the first embodiment of pump dispenser  10 , pump dispenser  100  may likewise be a manually operated pump dispenser, described in detail in the aforementioned U.S. patent application Ser. No. 10/214,160. In addition to the standard components described above for pump dispenser  10 , pump dispenser  100  may include a discharge valve assembly  102  and a depending sleeve  104  for mounting plunger head  106  to an upper end of hollow piston stem  108  of a piston having at its lower end an annular piston seal (not shown) in sliding sealing engagement with the inner wall of a pump cylinder. Plunger head  106  may include a depending sleeve  110  which frictionally engages the upper end of piston stem  108  to effect a tight seal, and an elongated transverse spout  112  defining a discharge passage  114  which directly communicates with the upper end of the piston stem. 
   Referring to  FIGS. 5 and 8 , the second embodiment of discharge valve assembly  102  according to the present invention comprises a unitary valve  116  of resilient material such as a silicone or thermoplastic elastomer of various durometers. Valve  116  may be supported by valve adaptor  118  disposed at a distal end of spout  112 , as described in greater detail below. Valve adaptor  118  may include an axial passage  120  which terminates in at least a pair of lateral passageways  122  with four such passageways  122  as illustrated in  FIG. 8 . Valve adaptor  118  may be frictionally or otherwise adhesively retained within bore  124  of spout  112 . 
   As illustrated in  FIGS. 5 and 8 , spout  112  may include a further bore  126  at a distal end thereof such that bore  126  is slightly greater in diameter than bore  124  so as to provide a stop means at annular wall  128  for enabling a predetermined depth of insertion of unitary valve  116  and valve adaptor  118  into bore  124 . Unitary valve  116  may be retained within bore  126  by engagement of annular rib  130  of unitary valve  116  between circumferential wall  131  of valve adaptor  118  and complementary annular wall  128 . The inner diameter of bore  126  in which valve  116  is seated may generally be equal to the outer diameter of valve  116  to permit axial expansion only of valve  116  upon the discharge of pressurized product through lateral passageways  122 , as discussed in greater detail below. 
   Referring to  FIGS. 5-8 , in the particular embodiment illustrated, valve  116  may include a star-shaped (or other, i.e. triangular, circular, rectangular etc.) configuration defined by outlet slits  136 , which in the embodiment of  FIG. 6 , may include five such outlet slits  136  formed integrally with circular skirt wall  138  of valve  116 . Slits  136  may be defined as gaps between generally pie-shaped walls  140 , which function to guide product through the adjacently disposed slits  136 . It should be noted that instead of outlet slits  136 , valve  116  may include a molded exit area (not shown), as would be apparent to those skilled in the art. Slits  136  may each terminate at the central axis of valve  116 , such that a generally uniform star-shaped cross-section of product is discharged through slits  136 . As illustrated in  FIG. 5 , skirt wall  138  may be formed of a substantially lesser thickness as compared to walls  140  defining slits  136  therebetween for permitting axial expansion only of valve  116  upon the discharge of pressurized product through lateral passageways  122 . 
   In order for product to be discharged through valve  116  during the downward stroke of plunger head  106 , for the orientation of slits  136  illustrated in  FIG. 6 , product discharged via spout  112  through valve  116  may first enter axial passage  120  of valve adaptor  118 , as illustrated by flow-paths B 1  and B 2 . Thereafter, product in axial passage  120  may generally uniformly enter lateral passageways  122  and divide into four flow-paths within the lateral passageways  122 , as illustrated by flow-paths B 3  and B 4 . As pressure from the product in lateral passageways  122  continues to increase during the downward stroke of plunger head  106  and reaches a predetermined threshold, further increase of pressure from the product during the continuing downward stroke of plunger head  106  deforms and expands valve  116  in an outwardly axial direction to unseat the structure forming walls  140  from valve seat  142  from the frontal surface  144  of valve seat  142 , and thereafter allow product to continue onwards and out through outlet slits  136 , as illustrated by flow-paths B 5  and B 6 . 
   When manual pressure applied to plunger head  106  is released or is interrupted, the pressure of product in area  148  decreases below the aforementioned predetermined threshold, such that the structure forming walls  140  quickly contracts axially inwardly to reach its rest configuration against frontal surface  144  of valve seat  142 , illustrated in  FIGS. 5 and 7 . Thus, at the end of a given downward stroke of the plunger head, just prior to the ensuing plunger up stroke, the structure forming walls  140  quickly contracts axially inwardly (i.e. relaxes) to prevent any further product from being discharged through outlet slits  136  of valve  116 , and thereby closes outlet slits  136  by means of the structure forming walls  140  and valve seat  142 . 
   With the flow of product from spout  112  through valve  116  via flow-paths B 1 -B 6 , the product output through valve  116  has a consistently uniform star-shaped cross-section by means of the product output through outlet slits  136 . Moreover, since the valve assembly according to the present invention includes only two components, namely valve adaptor  118  and unitary valve  116 , the reduced number of components facilitates easy and economical manufacture and assembly of the pump dispenser, while providing repeatability in the cross-sectional quality of the discharged product over the life of the pump dispenser. Furthermore, the efficient operation of unitary valve  116  provides a pump dispenser which will quickly respond for sealing the discharge flow path during each piston suction stroke irrespective of the viscosity of the product being dispensed. 
   The third embodiment of pump dispenser  200  will now be described in detail with reference to  FIGS. 9-12 . 
   As shown in  FIG. 9 , in a similar manner as the first and second embodiments of pump dispensers  10  and  100 , respectively, pump dispenser  200  may likewise be a manually operated pump dispenser, described in detail in the aforementioned U.S. patent application Ser. No. 10/214,160. In addition to the standard components described above for pump dispensers  10  and  100 , pump dispenser  200  may include a discharge valve assembly  202  and a depending sleeve  204  for mounting plunger head  206  to an upper end of hollow piston stem  208  of a piston having at its lower end an annular piston seal (not shown) in sliding sealing engagement with the inner wall of a pump cylinder. Plunger head  206  may include a depending sleeve  210  which frictionally engages the upper end of piston stem  208  to effect a tight seal, and an elongated transverse spout  212  defining a discharge passage  214  which directly communicates with the upper end of the piston stem. 
   Referring to  FIGS. 9 and 12 , the third embodiment of discharge valve assembly  202  according to the present invention comprises a unitary valve  216  of resilient material such as a silicone or thermoplastic elastomer of various durometers. Valve  216  may be supported by valve adaptor  218  disposed at a distal end of spout  212 , as described in greater detail below. Valve adaptor  218  may include an axial passage  220  which terminates in at least a pair of lateral passageways  222  with four such passageways  222  as illustrated in  FIG. 12 . Valve adaptor  218  may be frictionally or otherwise adhesively retained within bore  224  of spout  212 . 
   As illustrated in  FIGS. 9 and 12 , spout  212  may include a further bore  226  at a distal end thereof such that bore  226  is slightly greater in diameter than bore  224  so as to provide a stop means at annular wall  228  for enabling a predetermined depth of insertion of unitary valve  216  and valve adaptor  218  into bore  224 . Unitary valve  216  may be retained within bore  226  by engagement of annular rib  230  of unitary valve  216  between wall  231  of valve adaptor  218  and complementary annular wall  228 . The inner diameter of bore  226  in which valve  216  is seated may be slightly larger than the outer diameter of valve  216  to permit radial and axial expansion of valve  216  upon the discharge of pressurized product through lateral passageways  222 , as discussed in greater detail below. 
   Referring to  FIGS. 9-12 , in the particular embodiment illustrated, valve  216  may include a star-shaped (or other, i.e. triangular, circular, rectangular etc.) configuration defined by expandable outlet slits  236 , which in the embodiment of  FIG. 10 , may include five such outlet slits  236  formed integrally with frusto-conical skirt wall  238  of valve  216 . Slits  236  may be defined as expandable gaps between generally pie-shaped walls  240 , which function to guide product through the adjacently disposed slits  236 . It should be noted that instead of outlet slits  236 , valve  216  may include a molded exit area (not shown), as would be apparent to those skilled in the art. Slits  236  may each terminate at the central axis of valve  216 , such that a generally uniform star-shaped cross-section of product is discharged through slits  236 . As illustrated in  FIG. 9 , skirt wall  238  may be formed of a substantially similar thickness as walls  240  defining slits  236  therebetween for permitting axial and radial expansion of valve  216  upon the discharge of pressurized product through lateral passageways  222 . 
   In order for product to be discharged through valve  216  during the downward stroke of plunger head  206 , for the orientation of slits  236  illustrated in  FIG. 10 , product discharged via spout  212  through valve  216  may first enter axial passage  220  of valve adaptor  218 , as illustrated by flow-paths C 1  and C 2 . Thereafter, product in axial passage  220  may generally uniformly enter lateral passageways  222  and divide into four flow-paths within the lateral passageways  222 , as illustrated by flow-paths C 3  and C 4 . As pressure from the product in lateral passageways  222  continues to increase during the downward stroke of plunger head  206  and reaches a predetermined threshold, further increase of pressure from the product during the continuing downward stroke of plunger head  206  deforms and expands valve  216  in an outwardly axial and radial direction to unseat the structure forming walls  240  from valve seat  242  from the frontal and lateral surfaces,  244 ,  246 , respectively, of valve seat  242 , and thereafter allow product to continue onwards and out through outlet slits  236 , as illustrated by flow-paths C 5  and C 6 . 
   When manual pressure applied to plunger head  206  is released or is interrupted, the pressure of product in area  248  decreases below the aforementioned predetermined threshold, such that the structure forming walls  240  and skirt wall  238  quickly contract axially and radially inwardly to reach its rest configuration against valve seat  242 , illustrated in  FIGS. 9 and 11 . Thus, at the end of a given downward stroke of the plunger head, just prior to the ensuing plunger up stroke, the structure forming walls  240  quickly contracts axially inwardly (i.e. relaxes) to prevent any further product from being discharged through outlet slits  236  of valve  216 , and thereby closes outlet slits  236  by means of the structure forming walls  240 , skirt wall  238  and valve seat  242 . 
   With the flow of product from spout  212  through valve  216  via flow-paths C 1 -C 6 , the product output through valve  216  has a consistently uniform star-shaped cross-section by means of the product output through outlet slits  236 . Moreover, since the valve assembly according to the present invention includes only two components, namely valve adaptor  218  and unitary valve  216 , the reduced number of components facilitates easy and economical manufacture and assembly of the pump dispenser, while providing repeatability in the cross-sectional quality of the discharged product over the life of the pump dispenser. Furthermore, the efficient operation of unitary valve  216  provides a pump dispenser which will quickly respond for sealing the discharge flow path during each piston suction stroke irrespective of the viscosity of the product being dispensed. 
   As discussed above, various modifications may be made to the first, second and third embodiments of pump dispensers  10 ,  100  and  200 , respectively, without departing from the scope of the present invention. For example, although a fixed number of lateral passageways  32 ,  122  and  222 , respectively, are illustrated in  FIGS. 4 ,  8  and  12 , for the first through third embodiments, the number of lateral passages may be increased or decreased as needed to alter the distribution of product from axial passages  30 ,  120  and  220 , respectively. Likewise, although a fixed number of outlet slits  46 ,  136  and  236  are illustrated in  FIGS. 2 ,  6  and  10 , respectively, for the first through third embodiments, the number of slits may be increased or decreased as needed to alter the cross-section of the product output. Further, although slits  46 ,  136  and  236  for the first through third embodiments, respectively, have been illustrated as including a generally rectangular cross-section, the cross-section of slits  46 ,  136  and  236  may be made elliptical, circular, include ridges or a variety of other shapes, for further altering the distribution and cross-section of product output therethrough. Moreover, whereas spout  22 ,  112  and  212  for the first through third embodiments, respectively, and the various components for discharge valve assemblies  12 ,  102  and  202 , respectively, have been illustrated as including a generally circular cross-section, those skilled in the art would appreciate in view of this disclosure that the aforementioned components may include an elliptical, rectangular or other cross-sections, for further altering the cross-section of product output through spout  22 ,  112  and  212  for the first through third embodiments, respectively. Further, while discharge valve assemblies  12 ,  102  and  202  for the first through third embodiments, respectively, have been illustrated herein for a manually operated pump dispenser, those skilled in the art would also appreciate in view of this disclosure that discharge valve assemblies  12 ,  102  and  202  may be used with squeeze or non-manually operated pump dispensers as well, i.e. a dispenser having a manually deformable side wall or wall portion, or a dispenser having a pump motor for discharging liquid product. It should also be noted that although discharge valve assemblies  12 ,  102  and  202  for the first through third embodiments, respectively, have been described as being used in addition to a separate discharge valve provided within pump dispenser assemblies  10 ,  100  and  200 , respectively, assemblies  12 ,  102  and  202  may be readily used in addition to or in lieu of a separate discharge valve provided within pump dispensers  10 ,  100  and  200 , as would be apparent to those skilled in the art. 
   Although particular embodiments of the invention have been described in detail herein with reference to the accompanying drawings, it is to be understood that the invention is not limited to those particular embodiments, and that various changes and modifications may be effected therein by one skilled in the art without departing from the scope or spirit of the invention as defined in the appended claims.