Abstract:
A fluid-dispensing device and method of dispensing fluid comprising a container for holding the fluid, a housing having an interior in which a portion of the container is located, and a source for compressing a portion of the container disposed within the interior of the housing. When the container is compressed, the fluid exits the container to flow to a desired location. The methods of compressing the container to force the fluid out of its interior include, for example, a housing holding the container that is pressurized above atmospheric pressure; an expandable balloon positioned adjacent the container and inflated; and a plate driven by a cylinder to compress the container. It is noted that this abstract is provided to comply with the rules requiring an abstract that will allow a searcher or other reader to ascertain quickly the subject matter of the technical disclosure. The abstract is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims pursuant to 37 C.F.R. §1.72(b).

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a method and apparatus for dispensing fluids and, more particularly, to a method and apparatus for dispensing viscous liquids, such as monomer.  
           [0003]    2. Background  
           [0004]    Many manufacturing processes require fluids to be dispensed or injected in a controlled manner. As one skilled in the art appreciates, controllably injecting viscous liquids often presents more challenges than less viscous fluids. An example of an industry that faces such challenges is the ophthalmic industry, which is involved in forming eyeglass lenses, contact lenses, and telescope and binocular lenses. Such lenses are typically formed in a molding process, in which a viscous lens-forming fluid, such as liquid monomer, is placed into a cavity of a lens-mold assembly defined by two molds and a gasket, after which the monomer subsequently cured into a polymeric structure.  
           [0005]    Problems that arise while dispensing liquid monomer into the lens mold assembly often result in defects in the final lens. For example, since the monomer is typically pumped from an open container through a dispensing pipe or tube into the lens mold cavity, air can mix with or otherwise become trapped within the monomer, potentially resulting in unacceptable bubbles or chemical changes within the final lens product. Another potential problem is that contamination, such as dust or other debris, sometimes becomes lodged in the piping and is introduced into the monomer, thus appearing in the final product.  
           [0006]    Another potential problem is that premature curing may occur of monomer remaining inside the piping, which is caused by heat generated by mechanical pumping devices or simply from heat absorption that occurs over time. This premature curing results in dispensing operations being halted until the line is unclogged. Similarly, when a change of monomer type is made between manufacturing processes, removal of all traces of the prior monomer type existing in the dispensing pipe or tube is usually necessary. Therefore, before each different monomer is used, it is often necessary to remove all extraneous monomer trapped in the dispensing piping by purging it with chemical solvents. This purging, however, is time consuming, messy, and produces chemical waste.  
           [0007]    To address these issues, lens-manufacturing processes have traditionally been performed in a large-scale, clean room manufacturing environment. Correspondingly, smaller-scale operations, such as in a doctor&#39;s office or the store of an eyeglass vendor, are uncommon.  
         SUMMARY OF THE INVENTION  
         [0008]    The present invention provides a fluid-dispensing device and method of dispensing fluid. The present invention includes a container for holding the fluid, a housing having an interior in which a portion of the container is located, and a means for compressing a portion of the container disposed within the interior of the housing. When the container is compressed, the fluid exits the container to enter a desired location, such as a lens-forming assembly to make a lens. Methods of compressing the container to force the fluid out of its interior include, for example, a housing holding the container that is pressurized above atmospheric or ambient pressure; an expandable balloon positioned adjacent the container and inflated; and a plate driven by a cylinder to compress the container.  
           [0009]    The present invention, as one skilled in the art will further appreciate, minimizes the amount of ambient air or other gases contacting the dispensed fluid because the container holding the fluid is sealed from atmosphere. Likewise, the present invention minimizes the amount of dirt, extraneous monomer, or other contamination that may potentially accumulate in the dispensing tube.  
           [0010]    As one skilled in the art will appreciate, the present invention is relatively simple to operate, yet allows controlled dispensing of fluids held within the container. The dispensed fluid is not itself pumped, which reduces heating of the fluid and further minimizes the chances that impurities will mix with the fluid being dispensed. Also, in the exemplary embodiment of the present invention discussed above, changing between fluids being dispensed is relatively easy (i.e., changing the container and associated tubing), as opposed to flushing out or purging pipes and tubes that interconnect with a pumping source during or between manufacturing operations.  
           [0011]    The method and apparatus of the present invention also allows for a clean, cost effective way to manufacture optical lenses in a standard office-type environment. The need for clean room and chemical waste disposal facilities are eliminated or greatly reduced. Depending on the design of the present invention, it additionally may be less expensive than other fluid dispensing technologies. Thus, using the present invention to form optical lenses makes more feasible the installation of a lens-forming device in a doctor&#39;s or an eyeglass vendor&#39;s office. 
       
    
    
     BRIEF DESCRIPTION OF THE FIGURES OF THE DRAWINGS  
       [0012]    [0012]FIG. 1 is a perspective view of an apparatus for dispensing fluids according to a first embodiment of the present invention.  
         [0013]    [0013]FIG. 2 is a perspective view of a bag assembly used as part of the apparatus according to the first embodiment of the present invention shown in FIG. 1.  
         [0014]    [0014]FIG. 3 is a perspective view of a second embodiment of an apparatus for dispensing fluids of the present invention.  
         [0015]    [0015]FIG. 4 is a cross-sectional view of an apparatus for dispensing fluids according to the second embodiment of the present invention shown in FIG. 3.  
         [0016]    [0016]FIG. 5 is a perspective view of an apparatus according to a third embodiment of the present invention.  
         [0017]    [0017]FIG. 6 is a side view, partially in cross-section, of FIG. 5.  
         [0018]    [0018]FIG. 7 is also a side view, partially in cross-section, showing an alternative design of the third embodiment illustrated in FIGS. 5 and 6.  
         [0019]    [0019]FIG. 8 is a perspective view of an apparatus according to a fourth embodiment of the present invention.  
         [0020]    [0020]FIG. 9 is a side view, partially in cross-section, of FIG. 8. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0021]    The present invention is more particularly described in the following examples that are intended as illustrative only since numerous modifications and variations therein will be apparent to those skilled in the art. As used in the specification and in the claims, “a,” “an,” or “the” can mean one or more, depending upon the context in which it is used.  
         [0022]    FIGS.  1 - 9  show exemplary embodiments and designs of present invention, which comprises a fluid-dispensing device  10  and method of dispensing fluid. In general, the present invention includes a container  20  for holding the fluid, a housing  40  having an interior  42  in which a portion of the container  20  is located, and a means for compressing a portion of the container  20  disposed within the interior  42  of the housing  40 . The preferred embodiments are now described in more detail below with reference to these figures, in which like numbers indicate like parts throughout.  
         [0023]    The illustrated embodiments are discussed in the context of dispensing a lens forming fluid, specifically monomer, which is viscous liquid. Monomer dispersed from the container  20  is injected into an optical lens in a mold (not shown), and an example of a mold assembly useful in conjunction with the present invention is disclosed in U.S. Pat. No. 6,099,764, which is incorporated herein in its entirety by reference. Those skilled in the art will appreciate, however, that the present invention has application to dispensing other fluids, including both gases and liquids.  
         [0024]    Prior to dispensing operations, the fluid (e.g., monomer in one exemplary embodiment) is added into the container  20  through the outlet  24  or other sealable orifice (not shown). The container  20  is sealed from ambient, which prevents the introduction of air, other fluids, or other contaminants surrounding the exterior of the container  20  from mixing with the fluid held within the container  20 . One skilled will appreciate that in addition to the container  20  being impermeable to contaminants, it should also be strong enough not to break when the compressing source exerts a force on the container  20  to cause the internal pressure to increase and dispense the fluid held within the container  20 .  
         [0025]    At least a portion of the surface  22  of the container  20  is deformable, flexible, or collapsible. For the container  20  illustrated in FIGS.  1 - 9 , substantially the entire surface  22  of the container  20  is deformable. One potential material of which the deformable portion of the container  20  may be formed is low-density polyethylene; however, any material that is sufficiently deformable, that can withstand the chemical properties of the fluid held therein, and that is capable of enduring the pressurized environment resulting from the compressing means may be employed. Although not presently preferred, it is contemplated that multiple materials may be used, some deformable and others rigid.  
         [0026]    As illustrated in FIGS.  1 - 9 , the outlet  24  of the container  20  is shown disposed at its lower portion, specifically, at its bottom. Although this positioning of the outlet  24  is not necessary, one skilled in the art will appreciate that it is beneficial for gravity to assist—instead of opposing—flow of the fluid out of the container  20 .  
         [0027]    As also illustrated, the outlet  24  is also connected to and in fluid communication with a first end  32  of a dispensing tube  30 . The dispensing tube  30  has an opposed second end  34  that is in fluid communication with a needle  12 , which is provided in the exemplary embodiment for inserting into the mold cavity (not shown). Thus, when fluid exits out of the outlet  24  of the container  20 , it enters the dispensing tube  30  through its first end  32 , travels therethrough, and then exits out of the second end  34  via the attached the needle  12 .  
         [0028]    In the illustrated embodiments, the dispensing tube  30  is of sufficient length so that it extends through the interior  42  of the housing  40  and its second end  34  is located outside of the interior  42 . The shape and diameter of the dispensing tube  30  should be chosen to promote laminar flow of the fluid held within the container  20  through its length. To avoid pinching of the dispensing tube  30  during use, it is preferable that the dispensing tube  30  be made from a material that is not subject to, or resistant to, deforming in the pressure exerted from the compression source that is applied to the container  20 . A semi-rigid plastic, such as medium-density polyethylene, may be used. Alternatively, the dispensing tube  30  may be made with the same material as the container  20  but with relatively thicker walls. The dispensing tube  30  is also preferably clear or translucent to allow viewing or inspection of the fluid as it passes through and along its length.  
         [0029]    [0029]FIGS. 1 and 5- 9  also show a valve  14  in communication with the dispensing tube  30  intermediate its first and second ends  32 ,  34 . The valve  14 , which is preferably located outside the interior  42  of the housing  40 , may be used for controlling the flow of fluid out of the dispensing tube  30 . Specifically, the valve  14  is movable between a shut position, in which fluid is hindered from traversing through the dispensing tube  30 , and an open position, in which fluid flow more freely occurs through the dispensing tube  30 . Although one design of the valve  14  is shown, those skilled in the art will appreciate various types can be used, including globe-type valves that stop and allow flow.  
         [0030]    The housing  40 , as noted above, has an interior  42  where at least a portion of the container  20  is located and, more specifically, where at least a portion of the deformable surface  22  of the container  20  is located. As one skilled in the art will appreciate, the housing  40  may take different shapes. FIGS. 1 and 5- 9  show the housing  40  being a cubical or rectangular structure with a top  44 , a bottom  46 , and four interconnecting walls  48 , but one skilled in the art will appreciate that other shapes are viable. Examples include cylindrical, spherical, and polygonal shapes or volumes. Also, all the illustrated embodiments show the presently preferred embodiment in which the entire container  20  is fully disposed within the interior  42  of the housing  40 , but as one skilled in the art will appreciate, it is not necessary that the container  20  be fully contained within the interior  42  to fall within the scope of the present invention.  
         [0031]    The method or means to compress the deformable portions of the container  20  may embody different forms, and the design of the housing  40  may change accordingly. Initially discussing a first embodiment of the present invention shown in FIGS. 1 and 2, the interior  42  of the housing  40  is a closed and substantially fluid-tight volume. A pressurized fluid source  70 , which is shown schematically and discussed in more detail below, is in fluid communication with the inlet orifice  50  and used to compress the deformable portions of the container  20  by increasing the pressure within the interior  42  of the housing  40 .  
         [0032]    Addressing in more detail the housing  40  used with this first embodiment, it is rectangular (but as noted above may take different alternative forms). Specifically, the housing  40  has a top  44 , a spaced-apart bottom  46 , and a plurality of walls  48  abutting each other and interconnecting the top  44  and bottom  46  so that, collectively, the housing  40  is air impermeable and rigid. Metal or high-density polyethylene is the preferred material for the walls  48 , although a rigid plastic may be used in the event the housing  40  is to be disposable.  
         [0033]    The housing  40  includes an inlet orifice  50 , which is preferably provided through the top  44  of the housing  40 . The inlet orifice  50  allows pressurized fluid from the pressurized fluid source  70 , such as air, another gas, or a liquid such as water, to flow through it into the interior  42  where the container  20  is located. Additionally, the housing  40  also preferably includes a sealable aperture  52  through which a portion of the dispensing tube  30  intermediate its first and second ends  32 ,  34  is disposed. This sealable aperture  52  is preferably provided through the bottom  46  of the housing  40 .  
         [0034]    Referring still to FIG. 1, one of the walls  48  of the housing  40  includes a sealable door  54  that is movable between an open position, in which the container  20  may be accessed within the interior  42  of the housing  40 , and a shut position, in which the interior  42  is substantially sealed from ambient. That is, when the door  54  is in the shut position as shown in FIG. 1, the housing  40  is sealed to hold a positive fluid pressure within its interior  42 . If the housing  40  is made of metal or other material that is not transparent, a clear viewing window  58  may be used to see the interior  42  when the door  54  is in the shut position.  
         [0035]    Accessing the interior  42  of the housing  40  through the door  54 , the operator can position the container  20  within its interior  42 . One or more brackets  56  (which may include standard-type screws or other fastening means) may attach to the top  44  or upper wall  48  of the housing  40 , which are in turn are capable of being removably fastened to hanging points  26  on the container  20 . Also attaching the container  20  to brackets  56  positioned at the lower portion of the housing  40  is also an option. The first end  32  of the dispensing tube  30  is also connected to the outlet  24  of the container  20  and the dispensing tube  30  is disposed through the sealable aperture  52 . After the container  20  is positioned and the door  54  is moved to its shut position, then the container  20  within the sealed interior  42  may be surrounded by fluid from the pressurized fluid source  70  entering through the inlet orifice  50 .  
         [0036]    The pressurized fluid source  70  can take numerous forms known in the art, such as a source of pressurized air or other gas, which may be embodied as an air compressor, a compressed gas cylinder or tank, and the like. Alternatively, the pressurized fluid source  70  may include a water pump or the similar device that injects a liquid into the interior  42  of the housing  40  through the inlet orifice  50 .  
         [0037]    When fluid from the pressurized fluid source  70  is added into the interior  42  of the housing  40  through its inlet orifice  50 , pressure within the interior  42  increases. The deformable surface  22  of the container  20  moves inwardly toward its opposed surface, causing the fluid within the container  20  to be forced through its outlet  24  to enter the dispensing tube  30  and traverse toward its second end  34 . Since the container  20  is sealed from ambient and the pressure applied to the surface  22  of the container  20  can be controlled, air bubbles and other distortions in the dispensed fluid are minimized. Also, since the fluid is not pumped in this design, less heat is added to the fluid as it traverses from its storage location (i.e., the container  20 ) to its destination (i.e., the mold).  
         [0038]    It is also preferred to use a regulating device  72 , such as an air regulator if compressed air is used, to control the amount of fluid injected or added into the interior  42  of the housing  40 . The regulating device  72  should be capable of ensuring that constant positive pressure is maintained within the interior  42  of the housing  40  sufficient to compensate for the loss of fluid in the container  20  as the container is deformed when the fluid it holds is dispensed out of its outlet  24 .  
         [0039]    With the components of the first embodiment outlined, the method of operation of one specific design is discussed. A tank of compressed air  70  is placed in fluid communication with the inlet orifice  50 , and air is controllably delivered to the housing  40  until a desired pressure is achieved inside the interior  42 . The dispensing needle  12  is placed into the cavity of the mold (not shown). As noted above, the present invention is described in the context of dispensing a viscous liquid, namely, monomer, in a lens forming process. As disclosed in U.S. Pat. No. 6,099,764, the lens forming assembly is formed from an elastomeric strip wrapped around the edges of two molds to form a sleeve-like structure, which in turn cooperates with the molds to form a molding cavity. To inject the monomer, the needle  12  attached to the second end  34  of the dispensing tube  30  pieces through the sleeve-like structure to communicate with the cavity of the mold. The elastomeric character of the sleeve-like structure also insures that no unnecessary air is introduced to the cavity. However, it should be understood that the present invention may also be used with other types of molding assemblies, as well as with other processes with which a controlled injection of fluid is desired or required.  
         [0040]    With the tip of the needle  12  positioned within and in fluid communication with the mold and with the interior  42  of the housing pressurized, the valve  14  is placed in its open position. The positive pressure within the interior  42  of the housing  40  surrounding the container  20  causes its surface  22  to deform by collapsing inwardly toward the opposed surface. Deformation of portions of the surface  22  forces the monomer within the container  20  through the dispensing tube  30  and then out the needle  12 .  
         [0041]    To avoid inconsistent flow rates of monomer from the container  20  and out through the needle  12  and to minimize the presence of bubbles and distortions in the final lens product, it is desirable that a consistent flow of monomer through the dispensing tube  30  be maintained throughout injecting operations. To achieve such a flow in this design, air is continually added into the interior  42  of the housing  40  through the inlet orifice  50  in an amount required to compensate for the volume of monomer exiting the container  40 . As noted above, the regulator  72  may be used to control automatically the pressure within the interior  42  to achieve a substantially constant velocity, pressure, and other flow properties of the monomer as it travels from the container  20 , through the dispensing tube  30 , and out the needle  12  into the mold. To further automate the process, a controller, such as an electronic processing unit (not shown), may be used for controlling the valve  14  to start and stop the flow of the monomer and also for controlling the pressure within the interior  42  of the housing  40  via the pressurized fluid source  70  and the regulator  72 .  
         [0042]    One skilled in the art will further appreciate that other designs of the first embodiment of the present invention may be used. For example, although not preferred, the entire surface  22  of the container  20  is not necessarily deformable. As another example, the entire container  20  does not need to be disposed within the interior  42  of the housing  40 , but as one skilled in the art will appreciate, the interior  42  must be substantially fluid-tight so that there is no communication (i.e., leakage) to ambient when the pressurized fluid is introduced therein.  
         [0043]    As another variation, a second embodiment of the present invention is shown in FIGS. 3 and 4 that includes an outer shell  60  and a liner  64 . The outer shell  60  has an inside surface  62  and the liner  64  is disposed within and substantially circumscribed by that inside surface  62  of the outer shell  60 . The liner  64  forms the closed volume of the housing  40  in which the container  20  is positioned. The outer shell  60  is preferably formed of a substantially rigid material and the liner  64  is formed of a flexible and fluid-impervious material. Thus, the outer shell  60  does not need to be sealable; rather, the liner  64  is capable of holding the pressurized fluid injected by the pressurized fluid source.  
         [0044]    Similar to the first embodiment shown in FIGS. 1 and 2, the inlet orifice  50  is in fluid communication with the interior  66  of the liner  64  and allows fluid to be controllably added into the interior  66  of the liner  64  from the pressurized fluid source. Likewise, the dispensing tube  30  extends through the liner  64  through a sealable aperture  52  and preferably through and out the outer shell  60 .  
         [0045]    In the method of using the second embodiment shown in FIGS. 3 and 4, pressurized fluid is injected into the interior  66  of the liner  64  through the inlet orifice  50 . The liner  64 , accordingly, acts in a similar manner as the interior  42  of the housing in the first described embodiment by holding a controllable positive fluid pressure against the deformable surface  22  of the container  20 . As that positive pressure pushes against the surface  22 , fluid held within the container  20  is dispensed through the dispensing tube  30 . Because the positive fluid pressure is contained within the fluid impervious liner  64 , there is no need for the surrounding container  20  to be sealable or made from expensive material. This advantageously enables the device  10  to be disposable. However, similar to the other embodiments, this design likewise minimizes distortions in the dispensed fluid, such as air bubbles.  
         [0046]    For other embodiments of the present invention, it may not be necessary to use a fluid-tight or sealed housing  40 . Referring now to FIGS. 5 and 6, a third embodiment of the present invention is shown. The method or means to compress the container  20  comprises at least one inflatable balloon  80  (or other inflatable structure) and a pressurized fluid source  70  in fluid communication with the balloon  80 . The balloon  80  is at least partially disposed within the interior  42  of the housing  40  adjacent the container  20 . Also, the balloon  80  may be similar to the liner  64  discussed above for FIGS. 3 and 4, e.g., the balloon  80  is fluid-impervious and is thus capable of being inflated with air, other gases, water, or other liquids. The balloon  80  may be formed of rubber, elastic polymer, or any other material that will allow it to inflate and, preferably, a material that will not stick to or otherwise adversely affect the surface  22  of the container  20 .  
         [0047]    The housing  40 , as noted above, does not need to be sealable in this embodiment. In fact, the housing  40  may be as simple as opposed walls  48  that stationarily position the balloon  80  and container  20  relative to each other. Thus, when the balloon  80  expands and is maintained at its relative position by its adjacent wall  48 , the balloon  80  compresses the container  20 , which is also held stationarily by its respective adjacent wall  48 , which is opposed to the wall positioning the balloon  80 . It is also advantageous to have a bottom  46  to interconnect the walls  48  of the housing  40 . FIGS. 5 and 6, however, illustrate that the housing  40  is similar to the design of the first embodiment, shown in FIGS. 1 and 2. That is, the housing  40  has a bottom  46 , a top  44 , four walls  48 , an inlet orifice  50  and aperture  52  through which the dispensing tube  30  is disposed, but as noted above, the interior  42  does not need to be sealable from ambient. A conduit  74  interconnects the inflatable balloon  80  and the pressurized fluid source  70  through the inlet orifice  50 . As described in the previous embodiments, a regulator may control the volume and pressure of fluid provided to the balloon  80 .  
         [0048]    In use, the container  20  holding the fluid to be dispensed is positioned within the interior  42  of the housing  40  between the balloon  80  and a wall  48  of the housing  40 . Air or another fluid from the pressurized fluid source  70  is injected or added into the balloon  80  through the conduit  74 , causing the balloon  80  to inflate. The wall  48  of the housing  40  having the door  54  stationarily positions the balloon  80  relative to the container  20  as it inflates and the container is squeezed or “sandwiched” between its adjacent wall  48  and the inflating balloon  80 . The deformable surfaces  22  of the compressed container  20 , accordingly, are forced inwardly as the balloon  80  continues to expand, forcing the fluid therein from its outlet  24  and through the dispensing tube  30 , if attached, and out of the attached needle  12 . That is, fluid from the pressurized fluid source  70  expands the balloon  80 , which correspondingly compresses a portion of the deformable surface  22  of the container  20  located within the interior  42  of the housing  40  inwardly so that fluid within the container  20  is forced through its outlet  24 . A controlled, consistent flow of the fluid from the container  20  is achieved by adding additional fluid to the balloon  80  to compensate for the volume of fluid leaving the container  20 .  
         [0049]    Referring now to FIG. 7, an alternative design of the third embodiment is shown. As will be noted, there are two balloons  80  and the container  20  is disposed intermediate those two balloons  80 . The pressurized fluid source  70  is in fluid communication with both balloons  80  via the conduit  74  that branches, although separate pressurized fluid sources (not shown) can be used for each respective balloon  80 . As illustrated, one balloon  80  is placed adjacent respective opposed surfaces  22  of the container  20  such that both balloons  80  each contact the surface  22  of the container  20 . These balloons  80  also contact the walls  48  of the housing  40 . As with the design shown in FIGS. 5 and 6, fluid is provided to the two balloons  80  shown in FIG. 7 through the conduit  74 , which inflates the balloons  80  and causes the surface  22  of the container  20  to be forced inwardly toward the opposed surface  22 . The balloons  80 , accordingly, “sandwich” and deform or constrict the container  20 , creating an internal pressure that dispenses the fluid (e.g., liquid monomer in one design) in the controllably consistent manner described above.  
         [0050]    Although not expressly illustrated, one skilled in the art will appreciate that other designs are also contemplated. For example, there may be three or more separate balloons that each circumscribes a portion of the surface of the container. Alternatively, there may be a single balloon having a gap in the center (similar to a doughnut) into which the container is disposed and that single balloon is inflated to constrict the surface of the container.  
         [0051]    Referring now to FIGS. 8 and 9, a fourth embodiment of the present invention is illustrated. The method or means to compress the container  20  comprises a moveable plate  90  (or some other force-applying structure) and a cylinder  92  for moving that plate  90  to contact a portion of the container  20 . The plate  90  is preferably a flat metal structure, but other hard materials of different shapes may be employed. The plate  90  is disposed facing one wall  48  of the housing  40  and at least a portion of the deformable surface  22  of the container  20  is disposed intermediate the plate  90  and the facing wall  49 .  
         [0052]    The cylinder  92  may embody any type of means for controllably driving or moving the plate  90 . One specific type of cylinder  92  is a Series CA1, 80 mm bore diameter-driving cylinder available from SMC Pneumatics Inc. of Indianapolis, Ind. Other exemplary types of cylinders include electrically-operated solenoids and cylinders.  
         [0053]    One skilled in the art will appreciate that in this embodiment, there is also no requirement that the interior  42  of the housing  40  be sealable or pressurized. As such, the housing  40  may be as simple as comprising a single wall  48 , the wall  49  facing the plate  90 . However, as illustrated in FIGS. 8 and 9, the housing  40  comprises a bottom  46  and a plurality of walls  48  circumscribing the container  20  and the plate  90 . The illustrated design also includes the dispensing tube  30  traversing through the bottom  46  and including a needle  12  attached to its second end  34 .  
         [0054]    During operation, the container  20  is positioned within the interior  42  between the plate  90  and the facing wall  49 . The cylinder  92  is actuated and the plate  90  is controllably moved to and against the container  20  holding the fluid, such as liquid monomer. When the cylinder  92  moves the plate  90  toward the container  20 , he facing wall  49  restrains the container  20  so that fluid located within the container  20  is forced through its outlet  24 . That is, the container  20  is squeezed between the plate  90  and the facing wall  49 , causing the surface  22  of the container  20  to deform. Deformation of the container  20 , as discussed above for the other embodiments, forces the fluid out of the container  20  through the dispensing tube  30  and out the dispensing needle  12  into the mold or other structure. Consistent flow of fluid out of the container  20  and through the dispensing tube  30  is achieved by controlling the cylinder  92  and, thus, the force applied to the container  20  by the plate  90 .  
         [0055]    Alternatively, multiple plates (not shown) may be provided. For example, the plates may be arranged in a side-by-side relationship and move in synchronization with each other. As another example, the plates may be oriented facing each other so that one plate is in the same position as the facing wall discussed above.  
         [0056]    Although the present invention has been described with reference to specific details of certain embodiments thereof, it is not intended that such details should be regarded as limitations upon the scope of the invention except as and to the extent that they are included in the accompanying claims. For example, although the present invention has been discussed in the exemplary context of injecting monomer in a lens forming process, the present invention has applicability to other processes in other arts and industries.