Patent Publication Number: US-2012024887-A1

Title: Liquid Butter Dispenser

Description:
BACKGROUND 
     Many restaurants, food service providers and restaurant chains strive to make their products consistent in order to control costs but also because patrons expect menu items to be consistent, regardless of where a particular menu item is purchased or which employee prepared it. Prepared food product consistency is difficult to achieve if different processes are used to prepare the product, as often happens when different employees of a restaurant use different amounts of ingredients to prepare the same item. 
     One way to help achieve food product consistency is to use the same ingredients, in the same amount. Prepared menu items can be made consistent by preparing an item using the same amount of each ingredient. Seasonings and toppings that are applied to a food item either before or after it is cooked are often applied in different amounts by different employees. Butter and margarine are considered herein to be toppings. 
     Many restaurants and restaurant chains offer breakfast foods that include English muffins. Many restaurants offer English muffins with toppings that are applied by the restaurant and thereafter served to a customer. 
     Consistently applying the same amount of butter or margarine to an English muffin is time consuming and problematic because of the surface roughness of an English muffin. A method and apparatus by which a liquid or melted butter or margarine, or other liquid food product can be consistently applied to food products like English muffins would be an improvement over the prior art. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of a dispenser of fluid products such as liquid or melted butter or margarine; 
         FIG. 2  is a perspective view of the dispenser shown in  FIG. 1  looking downwardly into the container of the dispenser; 
         FIG. 3  is a perspective view of the bottom of the dispenser shown in  FIG. 1  and showing dispensing valves through which a liquid food product passes; 
         FIG. 3A  is an isolated view of the dispensing valves shown in  FIG. 3 ; 
         FIG. 4  is another perspective view of the dispenser shown in  FIG. 1 , looking downwardly into the container and showing a pump at the bottom of the container which drives liquid food products outwardly and showing a piston actuating lever which extends across the container; 
         FIG. 5  is a cross sectional view of the dispenser shown in  FIG. 1 ; 
         FIG. 6  is an exploded view of the dispenser; 
         FIG. 7  is an exploded view of the pump which captures a volume of the fluid product from the container and discharges it from the dispenser; 
         FIG. 8  is a cross sectional view of the pump shown in  FIG. 7 . 
         FIGS. 9(A)-9(F)  depict the capture, enclosure, translation, and dispensing of a liquid product from the pump shown in  FIGS. 7 and 8 ; 
         FIG. 10  is a cross sectional view of the dispenser with a pump displacement limiter; 
         FIG. 11  is a top view of the dispenser shown in  FIG. 10 ; 
         FIG. 12  is a cross sectional view of the dispenser with an alternate embodiment of a pump displacement limiter; and 
         FIGS. 13A and 13B  are isolated views of the pump displacement limiter. 
     
    
    
     DETAILED DESCRIPTION 
     Reference is made to the accompanying figures.  FIG. 1  is a side view of a dispenser  10  for relatively viscous fluid food products  10  that include melted butter and/or margarine and salad oil. The dispenser will work with fluids having other viscosities within a viscosity range of 1 to about 100,000 centipoise. 
     Viscosity is an internal property of a liquid that offers resistance to flow. In a sense, viscosity is liquid friction. 
     Viscosity is the inverse of fluidity, i.e., viscosity=1/fluidity. The unit of measure of viscosity is centipoise. 1 centipoise (cp)=0.01 dyne-sec/cm 2 . The higher the coefficient of viscosity, the higher is the liquid&#39;s viscosity. Viscosity is also dependent upon temperature however. In general, the viscosity of a liquid varies inversely with the liquid&#39;s temperature. The higher the temperature of a liquid, the lower will be its viscosity. At room temperature, butter has a viscosity of about 50,000-75,000 cp. Melted butter on the other hand has a lower viscosity of about 1,000 up to about 5,000 cp. 
     Virtually any liquid with a viscosity of between about 1 cp up to about 100,000 cp can be dispensed using the dispenser disclosed herein but whether a liquid can be dispensed can also depend on a liquid&#39;s thixotropic characteristics. 
     Thixotropy is a property of various gels that become fluid when disturbed, such as by shaking Thixotropic means that a liquid&#39;s viscosity decreases as stress on the liquid increases. Substances which are thick like a solid, but which flow like a liquid when a sideways force is applied to them, are called thixotropic. 
     A thixotropic fluid undergoes a decrease in viscosity with time, while it is being subjected to constant shearing. Ketchup and mayonnaise are examples of thixotropic materials. Mayonnaise has a viscosity of about 28,000 cp; ketchup has a viscosity of about 75,000 cp. They appear thick or viscous, but can nevertheless be pumped because they are thixotropic. 
     The preferred embodiment of the dispenser  10  is comprised of a rigid container  12 , preferably made of molded plastic or molded fiberglass. The container  12  has a top portion that is also referred to as a top part  14 . The top part  14  has a shape reminiscent or suggestive of a rectangular parallelepiped, which is well known to be a six-faced polyhedron all of whose faces are parallelograms lying in pairs of parallel planes and wherein the faces of the polyhedron meet at right angles. 
     The top part  14  is hollow and has an open top  16 , as can be seen in  FIG. 1  and  FIG. 2 . The open top  14  allows fluid food products to be poured into the rigid container  12 . Thixotropic liquids can be “scooped” into the open top  14 . 
     The parallelepiped-shaped top part  14  has a bottom edge identified by reference numeral  18 . The bottom edge is joined to, attached to, or formed with, a substantially funnel-shaped portion  20 . The bottom edge  18  of the top part  14  corresponds to the top edge of the funnel-shaped portion  20 . 
     The funnel-shaped portion  20  has a bottom edge  22 , which is joined to, attached to, or formed with, a substantially cylindrical discharge portion  24 . The bottom edge  22  of the funnel-shaped portion also corresponds to the top edge of the discharge portion  24 . 
     As can be seen in  FIGS. 1-3 , the discharge portion  24  is cylindrical. It has a bottom portion  26  having a shoulder part that narrows the discharge portion  24 . The bottom portion  26  is provided with several holes  29  through which fluid food products from the inside of the rigid container are discharged by the action of a pump assembly  40  located inside the discharge portion  24 . A handle  32  is attached to one side of the top part  14  and to the discharge portion. 
     Fluid food products are dispensed from the dispenser  10  by grasping a handle  32  attached to one side of the rigid container  12  and depressing a tab  82 , which is one end of a piston actuator  34 , not visible in  FIG. 1 ,  2  or  3  but seen best in  FIGS. 4 and 5 . The handle  32  is substantially “D” shaped, which facilitates a user grasping the handle  32  with four fingers and actuating the tab  82  with a thumb. 
     As can be seen in  FIGS. 4 and 5 , the piston actuator  34  is essentially a beam. The piston actuator  34  extends across the open top  16  of the parallelepiped-shaped top part  14 . The distal end, which is away from the handle  32 , is inserted into an opening formed in an opposite side wall of the top part  14 . 
       FIG. 3  shows that the bottom of the discharge portion  26  is comprised of protuberances  31  that extend from the bottom  26  of the discharge portion  30 . The protuberances  31  have a shape reminiscent of a cylinder, on top of which is a zone of a sphere. A zone of a sphere is considered herein to be the portion of a sphere contained between two, spaced-apart parallel planes, which both intersect the sphere. 
     The protuberances  31  have relatively small diameter dispensing holes  29 , which are covered by dispensing valves  30 , such as the ones disclosed in U.S. Pat. No. 5,339,995, issued Aug.  23 ,  1994 . The dispensing valves  30  are identified in the &#39;995 patent by reference numeral 3. The contents of U.S. Pat. No. 5,339,995 are therefore incorporated herein in its entirety, as are the contents of U.S. Pat. No. 5,439,143 and U.S. Pat. No. 5,213,236. 
     Liquid and liquid food in the rigid container  12  is dispensed from the holes  29  and through the dispensing valves  30  using a pump assembly  40  inside the discharge portion  24 . The pump assembly  40  is comprised of a holding cup  42 , which fits inside a cylindrical interior portion of the discharge portion  24 , and a piston assembly  52  that reciprocates up and down inside the cup  42 . The cylindrical interior portion of the discharge portion  24  is hereafter referred to as a cylinder  36  inside the discharge portion  24 . 
       FIGS. 6 ,  7  and  8  show that the holding cup  42  is essentially a cylinder having an inside diameter, an outside diameter, a closed and substantially planar bottom  44  and an open top  50 . The outside diameter of the cup  42  is selected so that the cup  42  fits snugly inside the cylinder  36 . The “closed” planar bottom  44  is provided with a hole  46 , through which liquid food products are discharged into the discharge portion  26 . 
     As stated above, the cup  42  fits snugly into the cylinder  36  formed into the inside of the discharge portion  24 . The holding cup  42  therefore does not move in the cylinder  36 . As best seen in  FIG. 8 , the outside bottom edge of the cup  42  is provided with a shoulder or chamfer identified by reference numeral  43 . The chamfer  43  is configured to receive an O-ring or gasket identified by reference numeral  43   a.  The O-ring  43   a  is made of a pliable material such as neoprene or the like. It provides a seal, which prevents fluid that seeps between the outside surface of the cup  42  and the cylinder  36  from leaking into the holes  29  formed into the bottom  26  of the discharge portion  24  and accumulating above the dispensing valves  30  where it might leak onto a surface that supports the dispenser  10 . 
     The inside diameter of the cup  42  is selected to receive a piston assembly  52  best seen in  FIGS. 6 ,  7  and  8 . The piston assembly  52  is configured to reciprocate up and down inside the cup  42 . As shown in  FIGS. 9A-9F  and as described below, up and down movement of the piston assembly  52  in the cup  42  captures liquid from the container  12 , seals it inside the cup  42  and drives the captured liquid/fluid through the hole  46  in the bottom of the cup  42 , through the holes  29  formed in the protuberances  31  and out through the dispensing valves  30 . 
     The piston assembly  52  moves downward in response to downward force exerted on the piston assembly  52  through the piston actuator  34 . The piston assembly  52  moves upward in response to an upward force exerted on the piston assembly  52  by a coil-type piston return spring  66 , which forms part of the piston assembly  52 . 
     As best seen in  FIGS. 6 ,  7  and  8 , the piston assembly  52  is comprised of a push rod  54  having a top end  74  and a bottom end, which is formed as a hemispherical-shaped cap  72 . The piston assembly  52  is also comprised of a disk  56 , a first check valve and the coil-type piston return spring  66 . 
     As mentioned above, the piston actuator  34  is essentially a beam, one end of which fits loosely into a hole formed into one side of the rigid container  12 , the other end of which is formed to extend over the user handle  32 . As can be seen in  FIGS. 4 ,  5  and  6 , the piston actuator  34  is provided with a hole that receives the top end  74  of the push rod  54 . The top end  74  of the push rod is narrowed to fit into the hole in the piston actuator  34  and to form a wider, shoulder  76 . Downward force applied to the user-actuating tab  82  of the piston actuator  34 , is therefore applied against the shoulder  76 , driving the push rod  54  downward. Driving the push rod  54  downward therefore drives the hemispherical cap  72  downward. Driving the cap  72  downward pushes the disk  58 , check valve and spring  66  downward and further into the cup  42 . 
     Referring now to  FIGS. 6 ,  7  and  FIG. 8 , the pump assembly  40  can be seen to be comprised of the fluid product holding cup  42  and the piston assembly  52 . Fluid from inside the rigid container  12  flows into the cup  42  through a check valve  51 , which is comprised of a stopper  60 , which translates up and down in the hole  58  formed into the disk part  58  of the piston assembly  52 . 
     As can be seen in the figures, the top  50  of the cylinder  48  that comprises the cup  42  is open. The cylinder  48  has an inside diameter selected to receive the piston assembly  52  into the open top  50  of the cylinder  48  and to permit the piston assembly  52  to freely move up and down in the cylinder  48 . The cup  42 , container  12  and piston assembly  52  are configured such that when the piston assembly  52  is at or near the top  50  of the cup  42 , the level of the “bottom” of the fluid in the container  12  is above the cup  42  and above the piston assembly  52 . A check valve in the piston assembly  52  allows fluid from the container  12  to flow into the cup  42  until the cup  42  is full. Downward force on the push rod  54  closes the check valve in the piston assembly  52  and drives the piston assembly downward in the cup  42 , against fluid that flowed into the cup  42  while the first check valve was open. 
     A second check valve  90  is operatively coupled to the hole  46  in the bottom  44  of the cup  42 . The second check valve  90  is normally closed until a downward force exerted on the second check valve  90 , through the captured fluid in the cup  42 , is great enough to open the second check valve  90 . When the second check valve  90  opens, fluid in the cup  42  flows through the hole  46 , out of the cup and into the discharge portion  24 . Additional force on fluid that flows into the discharge portion  24  from the cup will drive the fluid in the discharge portion  24 , into holes  29  formed in the bottom  26  of the discharge portion  24  and through the dispensing valves  30  that cover and seal the holes  29 . 
     The first check valve  51  is comprised of a relatively thin, substantially planar rigid disk  56  having a central hole  58 , a stopper  60  which moves up and down in the central hole  58 , and the hemispherical cup  72 . The disk  56  has an outside diameter slightly less than the inside diameter of the cup  42  so that the disk  56  can freely translate up and down, i.e., reciprocate, inside the cup  42  but also be able to force or drive fluid out of the cup  42  in response to force applied to the piston assembly  52 . A groove  53  is preferably formed into the peripheral edge of the disk  56 . The groove  53  is sized, shaped and arranged to receive an O-ring  55 , which improves the seal between the disk  56  and the inside surface of the cylinder  48  of the cup  42 . The O-ring  55  is, of course, preferably made of a pliable material suitable for use with food products and the material from which the dispenser parts are made. 
     The hole  58  that extends through the disk  56  has a predetermined diameter, selected to freely receive the stopper  60 . The stopper  60  has a round and substantially planar, disk-like bottom end  64 . Four, L-shaped prongs  61  extend “upwardly” from the planar bottom end  64  and have a predetermined length, which is selected such that when the stopper  60  is installed in the disk  56 , the vertical portions the L-shaped prongs  61  extend through the hole  58  in the disk  56  and are able to extend to the top of the inside surface of the cap  72 . The top of the vertical portions of the L-shaped prongs  61  define a top end  62  of the stopper  60 . The stopper  60  is preferably molded from a plastic that is sufficiently flexible to allow for the insertion of the prongs into the hole. 
     While the top end  62  of the stopper  60  extends into the cap  72 , the bottom  64  of the stopper  60  contacts the top end  68  of the coil-type piston spring  66 . The bottom end  70  of the spring  66  works against the bottom  44  of the cup  42 . The characteristics of the spring  66  are selected in order to be able to push the disk  56  and the stopper  60  upwardly and away from the bottom  44  of the cup  42 , when there is no downward force applied to the piston assembly  52  by the piston actuator  34 . 
     As best seen in  FIG. 7 , the horizontal portions  63  of the L-shaped prongs  61  have a height, relative to the surface of disk-like bottom end  64 . The height of the horizontal portions  63  of the prongs  61  prevent the disk-like bottom end  64  from making contact with the lower surface of the disk  56 , which would close the hole  58 . The horizontal portions  63  of the prongs  61  thus keep the hole  58  “open” by holding the bottom end  64  of the stopper  60  away from the disk  56 . 
     The prongs  61  of the stopper  60  and the diameter of the hole  58  are selected so that the stopper prongs  61  fit loosely inside the hole  58 . The loose fit of the stopper prongs  61  thus allows the stopper  60  to move up and down in response to forces applied to it by the hemispherical cup  72  and the coil spring  66 . 
     The first coil spring  66 , which is located below the bottom end  64  of the stopper  60  and above the bottom of the cup  42 , applies an upward force against the bottom end  64  of the stopper. When the horizontal portions  63  of the L-shaped prongs  61  engage the bottom face of the disk  56  due to the upward force from the spring  66 , the same force is transmitted through the stopper  60  to the disk  56 , push rod  34  and the piston actuator  34 . 
     In  FIG. 5 , the arrow identified by reference numeral  80  is a vector representing downward force applied (by a user) to an actuating tab  82 . Driving the piston actuator  34  downward drives the push rod  54  downwardly. Driving the push rod  54  downward will drive the top end  62  of the stopper  60  downward and against force applied to the stopper  60  by the first coil spring  66 . In order to drive the piston assembly  52  downward, the force exerted on the cap  72  needs to at least overcome the upward force provided by the spring  66 . It also needs to overcome friction between the O-ring  55  and the cylinder  48 , as can be seen in  FIG. 7 . 
     When the cap  72  is driven downward, it eventually meets the top surface of the disk  56 . Since the inside diameter of the hole  58  through the disk  58  is less than the inside diameter of the cup  72 , the cup  72  effectively covers and closes the hole  58  in the disk  56  when the cup  72  meets the top surface of the disk  56 . When the hole  58  is closed, fluid in the container  12  cannot flow into the cup  42 . An optional O-ring  57 , formed of a soft, pliable material suitable for use with a food product, is therefore sized and shaped to fit around the prongs  61  of the stopper  60 . The O-ring  57  is placed between the disk  56  and the cap  72  to enhance the seal between the cap  72  and the disk  56  when the cap  72  is driven downwardly and into engagement with the disk  56 . 
     As mentioned above, the first coil spring  66  biases or urges the stopper  60  upwardly. When the stopper  60  is pushed upwardly, the top end  62  of the stopper  60  pushes against the hemispherical cap  72 . If the force from the coil spring  66  is greater than downward force applied through the cup, as happens when a user releases the user actuating tab  82 , the cap  72  is moved upwardly and away from the disk  56 , opening the first check valve  52 , by exposing the hole  58  in the disk  56  to liquid inside the container  12 . 
     The volume of the cup  42  below the disk  56  and above the planar bottom  44  of the cup  42  defines a maximum volume that can be captured inside the piston. As mentioned above, captured liquid is considered to be liquid that flows into the cup  42 . Fluid in the cup is “captured” in the cup  42  when the first check valve  52  closes. The first check valve  52  closes when the cap  72  is pushed downwardly and into engagement with the top of the disk  56 , closing the hole  58 . Captured fluid in the cup  42  is translated downwardly in the cup  42 , through the hole  48  in the bottom  44  of the cup  42 , into the bottom  26  of the discharge portion  24  and out of one or more holes  29  formed into the bottom  26  of the discharge portion  24 , by the application of additional downward force on the cap  72  via the push rod  54 /user actuating tab  82 . 
     A second check valve  90  is provided at the bottom of the cup  42 . The second check valve  90  is configured to open and allow fluid to flow out of the cup  42  and into the discharge portion  24  in response to downward force applied to liquid in the cup  42  from the piston assembly  52 . The second check valve  90  closes when the piston assembly  52  moves upward in the cup, i.e., away from the bottom of the cup  42 . It thus prevents fluid from being drawn up into the cup  42 . 
     As best seen in  FIGS. 7 and 8 , the second check valve  90  is comprised of a substantially planar disk  92 , having a stopper portion  94  that extends upwardly through a hole  46  formed in the planar bottom  44  of the cup  42 . This second disk  92  also has four, partial-annulus openings  93  that allow fluid from the hole  46  to flow through the disk  92 . 
     A second coil spring  96  is located below the bottom of the stopper  94  and above the bottom  26  of the discharge portion  24  to bias the stopper  94  upwardly. When the second planar disk  92  portion of the second stopper  94  is biased against the bottom  44  of the cup  42 , the hole  46  in the bottom  44  of the cup  42  is sealed. 
     The second spring  96  is compressed downwardly and the hole  46  opened when hydrostatic pressure inside the cup  42  exceeds the force applied to the planar disk  92  by the second spring  96 . Stated another way, when the hydrostatic force applied to a fluid product inside the cup  42  exceeds the force applied to the planar disk  92  of the second stopper  94 , the planar disk  92  will be urged downwardly and away from the planar bottom  44  of the cup  42 . Liquid inside the cup  42  is thereafter driven through the hole  46  and into the discharge openings  29  formed in the bottom  26  of the discharge portion  24 . 
     The disk  56  and cup  42  are configured such that the disk  56  fits snugly in the cup  42 . Upward movement of the disk  56  will thus create a negative pressure inside the cup  42 . Negative pressure, i.e., a partial vacuum, inside the cup  42  will slow the disk&#39;s upward movement, but a negative pressure inside the cup  42  will also draw liquid from the container  12  into the cup  42  through the hole  58 . When downward force/pressure is released, the spring will overcome the partial vacuum and allow the assembly to return to its quiescent or starting position. 
       FIGS. 9A ,  9 B,  9 C,  9 D and  9 E collectively show how the dispenser  10  operates to dispense fluid. In  FIG. 9A , the cap  72  is away from the disk  58  because no force is applied to the push rod  54 . The horizontal portions of the L-shaped prongs  61  of the first stopper  60  hold the bottom end  64  of the stopper  60  away from the disk  56 . Liquid  100  in the container  12  flows into the cup  42  through the hole  58  in the disk  56 . 
     In  FIG. 9B , downward force on the push rod  54  drives the hemispherical cap  72  downward. The cap  72  covers and closes the hole  58 . When the hole  58  is closed, liquid  100  inside the cup  42  is captured. 
     In  FIG. 9C , additional downward force through the push rod  54  drives the hemispherical cap  72  farther down. Pressure below the piston assembly  52  and inside the cup  42  increases the hydrostatic pressure inside the cup  42  until the bias force applied by the second spring  90  is overcome and the second stopper through the hole in the bottom of the cup  42  is pushed downwardly, opening the hole in the bottom of the cup  42 . Liquid  100  inside the cup  42  is thereafter pushed through the holes  93  in the disk  92  and into the discharge portion  24  below the bottom  44  of the cup. 
     Additional hydrostatic pressure drives the liquid  100  completely down into the discharge portion and out of the discharge opening  30  as shown in  FIG. 9D . Continued downward force  104  on the push rod  54  eventually empties the contents of the piston  40 . Since the volume inside the cup  42  is fixed, repeated cycling of the piston assembly  52  results in a constant or nearly-constant volume of liquid  100  being discharged on each complete actuation of the piston actuator  34 . 
     The pump assembly  40  is in reality a positive displacement pump. Its displacement on each actuation, and hence the volume of liquid that is dispensed on each actuation of the piston actuator  34 , is a function of the diameter of the cup  42  and the length of the stroke of the piston assembly  52  in the cup  42 . The volume of liquid that is dispensed on each actuation can therefore be selectively controlled, i.e., changed by a user, by limiting the piston assembly  52  travel in the cup  42 . The volume of a cylinder is defined by: V=π r 2 h=π(d/2) 2 h, where r=inside radius of a cylinder, d=diameter of a cylinder, h=height of cylinder or stroke 
       FIG. 10  is a cross sectional view of a liquid butter dispenser that also depicts a first embodiment of a pump displacement limiter  120 .  FIG. 11  is a top view of the dispenser shown in  FIG. 10  with the piston actuator  34  removed. 
     The pump displacement limiter  120  shown in  FIGS. 10 and 11  is embodied as a rotatable hub  121  that is rotatably attached to the handle  32 . Three lobes  124 ,  126  and  128 , each having a different height, extend outwardly from the hub  121 . A thumbwheel  122  is attached to one end of the hub  121 . Rotation of the thumbwheel  122  rotates the hub  121 . Rotation of the hub  121  positions a different one of the lobes  124 ,  126  and  128  under the tab  82 . The maximum downward deflection of the tab  82  is thus limited by the particular lobe  124 ,  126  and  128  that is rotated under the tab  82  by rotation of the thumbwheel  122 . 
     Reducing the downward travel distance of the actuator  34  by the height of the lobes  124 ,  126  and  128  reduces the piston assembly  52  stroke length in the cup  42  accordingly. Reducing the piston assembly stroke length, reduces how much liquid is dispensed each time that the piston actuator  34  is depressed. By controlling the piston stroke travel using discrete distances defined by the different lobes, the limiter  120  in  FIGS. 10 and 11  defines specific amounts of liquid that can be dispensed on each actuation of the piston assembly depending on which lobe is rotated into position. 
       FIG. 12  and  FIGS. 13A and 13B  depict an alternate embodiment of a pump displacement limiter  140 , and which can control the amount of liquid dispensed on each actuation, continuously. In  FIGS. 12 ,  13 A and  12 B, a thumbscrew  142  limits the distance that the piston actuator  34  can travel upwardly, which controls the amount of fluid that can be captured by the piston. 
     The thumbscrew  142  has a threaded shank  144 , which extends through a slot  145  formed into the actuating tab  82 . The thread on the shank  144  mate with and engage a threaded hole  146  that extends through the flat lip  147  surrounding the open top  16 . Rotating the head  143  of the screw  142  causes the screw  142  and screw head  143  to move up and down in the threaded hole  146 , relative to the lip  147 . 
     In  FIG. 13A , the actuating tab  82  is shown in an “up” position, resting against the bottom of the head  143  of the thumbscrew  142 . In  FIG. 13B , the user actuating tab  82  is shown in a “down” position, resting against the flat lip  147  surrounding the open top  16 . The up and down distance that the user actuating tab  82  travels limits the amount of fluid captured by the piston assembly. The volume of liquid discharged by each actuation of the tab  82  is thus controlled by controlling the vertical travel of the user actuating tab  82  with the volume of dispensed liquid being continuously variable depending on the position of the thumbscrew. 
     Those of ordinary skill in the art will recognize that clearances between the side wall of the cup  42  and cylinder  36  that the piston  40  translates in will allow material inside the rigid container to leak past and settle at the bottom  26  of the discharge portion  24 . An accumulation of the material will eventually leak through the discharge openings  30  unless a closure is provided to retain the liquid inside the discharge openings. An effective dispensing valve is disclosed in U.S. Pat. No. 5,439,143, which is entitled “Dispensing Valve for Packaging.” The &#39;143 patent issued on Aug. 8, 1995, the term of the patent subsequent to May 25, 2010, was disclaimed. The contents of the &#39;143 are incorporated herein in their entirety. 
     An additional dispensing valve is disclosed in U.S. Pat. No. 5,339,995 which issued Aug. 23, 1994, and which is entitled, “Dispensing Valve for Packaging.” The contents of the &#39;995 patent are also incorporated herein in its entirety. 
     Descriptions of the structure and operation of the dispensing valves  110  depicted in  FIG. 3 , as being attached to and extending over the discharge openings  30 , control the flow of liquid product from those discharge openings  30 . A complete description of their operation and structure can be found in the aforementioned &#39;995 patent and or the &#39;143 patent. A detailed description of them is omitted for brevity. 
     The foregoing description is for purposes of illustration only. The true scope of the invention is set for in the appurtenant claims.