Abstract:
A compact fluid dispenser for use in controllably dispensing fluid medicaments, such as antibiotics, oncolytics, hormones, steroids, blood clotting agents, analgesics, and like medicinal agents from prefilled containers at a uniform rate. The dispenser uniquely includes a stored energy source that is provided in the form of a substantially constant-force, compressible-expandable wave spring that provides the force necessary to continuously and uniformly expel fluid from the device reservoir. The device further includes a fluid flow control assembly that precisely controls the flow of medicament solution to the patient. Additionally, the device includes a novel modulating assembly for controllably modulating the force exerted by the wave spring tending to expel the fluid from the device reservoir.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates generally to medicament infusion devices. More particularly, the invention concerns an improved apparatus for infusing medicinal agents into an ambulatory patient at specific rates over extended periods of time, which apparatus includes a novel modulated energy source provided in the form of a compressible spring, and a novel flow rate control means for precisely controlling the rate of fluid flow from the reservoir of the device.  
         [0003]     2. Discussion of the Prior Art  
         [0004]     A number of different types of medicament dispensers for dispensing medicaments to ambulatory patients have been suggested. Many of the devices seek either to improve or to replace the traditional gravity flow and hypodermic syringe methods, which have been the standard for delivery of liquid medicaments for many years.  
         [0005]     The prior art gravity flow methods typically involve the use of intravenous administration sets and the familiar flexible solution bag suspended above the patient. Such gravametric methods are cumbersome, imprecise and require bed confinement of the patient. Periodic monitoring of the apparatus by the nurse or doctor is required to detect malfunctions of the infusion apparatus.  
         [0006]     Many medicinal agents require an intravenous route for administration thus bypassing the digestive system and precluding degradation by the catalytic enzymes in the digestive tract and the liver. The use of more potent medications at elevated concentrations has also increased the need for accuracy in controlling the delivery of such drugs. The delivery device, while not an active pharmacologic agent, may enhance the activity of the drug by mediating its therapeutic effectiveness. Certain classes of new pharmacologic agents possess a very narrow range of therapeutic effectiveness, for instance, too small a dose results in no effect, while too great a dose can result in a toxic reaction.  
         [0007]     For those patients that require frequent injections of the same or different amounts of medicament, the use of the hypodermic syringe method of delivery is common. However for each injection, it is necessary to first draw the injection dose into the syringe, then check the dose and, after making certain that all air has been expelled from the syringe, finally, inject the dose either under bolus or slow push protocol. This cumbersome and tedious procedure creates an unacceptable probability of debilitating complications, particularly for the elderly and the infirm.  
         [0008]     As will be appreciated from the discussion, which follows, the apparatus of the present invention is uniquely suited to provide precise, continuous fluid delivery management at a low cost in those cases where a variety of precise dosage schemes are of utmost importance. An important aspect of the apparatus of the present invention is the provision of novel fill means for filling the reservoir of the device using a conventional medicament vials or cartridge containers of various types having a pierceable septum. Another novel feature of the apparatus of the present invention comprises a unique, modulated stored energy source. A further unique feature is the provision of various fluid flow rate control means, including an embedded micro fluidic capillary multichannel flow rate control means, which enables precise control of the rate of fluid flow of the medicament to the patient. More particularly, the apparatus of the present invention includes a unique, adjustable fluid flow rate mechanism, which enables the fluid contained within the reservoir of the device to be precisely dispensed at various selected rates.  
         [0009]     The apparatus of the present invention can be used with minimal professional assistance in an alternate health care environment, such as the home. By way of example, devices of the invention can be comfortably and conveniently removably affixed to the patient&#39;s body or clothing and can be used for the continuous infusion of injectable anti-infectives, hormones, steroids, blood clotting agents, analgesics, and like medicinal agents. Similarly, the devices of the invention can be used for most I-V chemotherapy and can accurately deliver fluids to the patient in precisely the correct quantities and at extended microfusion rates over time.  
         [0010]     By way of summary, the apparatus of the present invention uniquely overcomes the drawbacks of the prior art by providing a novel, disposable dispenser of simple but highly reliable construction. A particularly important aspect of the apparatus of the present invention resides in the provision of a novel, self-contained modulated energy source comprising a compressible-expandable spring members that provides the modulated force necessary to uniformly and precisely dispense various solutions from standard prefilled vial containers that can be conveniently loaded into the apparatus. Because of the simplicity of construction of the apparatus of the invention, and the unique nature of the energy source, the apparatus can be manufactured at low cost without in any way sacrificing accuracy and reliability.  
         [0011]     With regard to the prior art, one of the most versatile and unique fluid delivery apparatus developed in recent years is that developed by the present inventor and described in U.S. Pat. No. 5,205,820. The components of this novel fluid delivery apparatus generally include: a base assembly, an elastomeric membrane serving as a stored energy means, fluid flow channels for filling and delivery, flow control means, a cover, and an ullage which comprises a part of the base assembly.  
         [0012]     Another prior art patent issued to the present applicant, namely U.S. Pat. No. 5,743,879, discloses an injectable medicament dispenser for use in controllably dispensing fluid medicaments such as insulin, anti-infectives, analgesics, oncolylotics, cardiac drugs biopharmaceuticals, and the like from a prefilled container at a uniform rate. The dispenser, which is quite dissimilar in construction and operation from that of the present invention, includes a stored energy source in the form of a compressively deformable, polymeric elastomeric member that provides the force necessary to controllably discharge the medicament from a prefilled container, which is housed within the body of the device. After having been deformed, the polymeric, elastomeric member will return to its starting configuration in a highly predictable manner.  
         [0013]     Another important prior art fluid delivery device is described in the U.S. Pat. No. 6,063,059 also issued to the present inventor. This device, while being of a completely different construction embodies a compressible-expandable stored energy source somewhat similar to that used in the apparatus of the present invention.  
         [0014]     Still another prior art fluid delivery device, in which the present inventor is also named as an inventor, is described in U.S. Pat. No. 6,086,561. This latter patent incorporates a fill system that makes use of conventional vials and cartridge medicament containers.  
       SUMMARY OF THE INVENTION  
       [0015]     It is an object of the present invention to provide a compact fluid dispenser for use in controllably dispensing fluid medicaments, such as, antibiotics, oncolytics, hormones, steroids, blood clotting agents, analgesics, and like medicinal agents from prefilled containers at a uniform rate.  
         [0016]     Another object of the invention is to provide a small, compact fluid dispenser that includes a housing to which fill vials can be connected for filling the dispenser reservoir with the fluid.  
         [0017]     Another object of the invention is to provide a dispenser in which a stored energy source is provided in the form of a compressible-expandable wave spring that provides the force necessary to continuously and uniformly expel fluid from the device reservoir.  
         [0018]     Another object of the invention is to provide a dispenser of the class described, which includes novel modulating means for modulating the force exerted by the compressible-expandable wave spring.  
         [0019]     Another object of the invention is to provide a dispenser as described in the preceding paragraphs that includes a novel fluid flow control assembly that precisely controls the flow of the medicament solution to the patient.  
         [0020]     Another object of the invention is to provide a dispenser that includes precise variable flow rate selection.  
         [0021]     Another object of the invention is to provide a fluid dispenser, which is adapted to be used with conventional prefilled drug containers to deliver beneficial agents there from in a precise and sterile manner.  
         [0022]     Another object of the invention is to provide a fluid dispenser of the class described which is compact, lightweight, is easy for ambulatory patients to use, is fully disposable, and is extremely accurate so as to enable the continuous infusion of precise volumes of medicament over prescribed periods of time.  
         [0023]     Another object of the invention is to provide a device of the character described which embodies a novel fluid volume indicator that provides a readily discernible visual indication of the volume of fluid remaining in the device reservoir.  
         [0024]     Another object of the invention is to provide a self-contained medicament dispenser which is of very simple construction and yet extremely reliable in use.  
         [0025]     Another object of the invention is to provide a fluid dispenser as described in the preceding paragraphs, which is easy and inexpensive to manufacture in large quantities. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0026]      FIG. 1  is a generally perspective front view of one embodiment of the medicament infusion apparatus of the present invention for dispensing fluids at a uniform rate.  
         [0027]      FIG. 2  is an enlarged, longitudinal cross-sectional view of the apparatus shown in  FIG. 1 .  
         [0028]      FIG. 2A  is an enlarged, fragmentary, cross-sectional view of a portion of the collapsible bellows component of the apparatus shown in  FIG. 1 .  
         [0029]      FIG. 3  is a cross-sectional view taken all lines  3 - 3  of  FIG. 2 .  
         [0030]      FIG. 4  is a cross-sectional view taken along lines  4 - 4  of  FIG. 2 .  
         [0031]      FIG. 5  is a cross-sectionalview taken along lines  5 - 5  of  FIG. 2 .  
         [0032]      FIG. 6  is a left end view of the apparatus shown in  FIG. 2 .  
         [0033]      FIG. 7  is a cross-sectional view taken along lines  7 - 7  of  FIG. 2 .  
         [0034]      FIG. 8  is an interior view of the bezel component of the apparatus shown in  FIG. 2 .  
         [0035]      FIG. 9  is a cross-sectional view taken along lines  9 - 9  of  FIG. 8 .  
         [0036]      FIG. 10  is a generally perspective, exploded view of the apparatus of the invention shown in  FIG. 2 .  
         [0037]      FIG. 10A  is an enlarged, generally perspective, exploded rear view of the forward portion of the apparatus shown in  FIG. 10 .  
         [0038]      FIG. 11  is an enlarged fragmentary cross-sectional view of a portion of the device housing showing one form of the air collar and control shaft of the stored energy means of the invention.  
         [0039]      FIG. 12  is a cross-sectional view taken along lines  12 - 12  of  FIG. 11 .  
         [0040]      FIG. 13  is an enlarged fragmentary cross-sectional view similar to  FIG. 11 , but showing the control shaft of the stored energy means moved into a second position.  
         [0041]      FIG. 14  is a cross-sectional view taken along lines  14 - 14  of  FIG. 13 .  
         [0042]      FIG. 15  is an enlarged fragmentary cross-sectional view showing the stored energy means of the apparatus of the invention in an intermediate fluid delivery position.  
         [0043]      FIG. 16  is an enlarged fragmentary cross-sectional view similar to  FIG. 15 , but illustrating the position of the operating components following completion of the delivery of the medicinal fluid from the fluid reservoir of the device.  
         [0044]      FIG. 16A  is a generally diagrammatic, graphical view illustrating the manner in which the force generated by the wave spring loading is modulated by the compression modulator or modulating means of the invention  FIG. 17  is a generally perspective, front view of one form of the fluid flow control assembly of the apparatus of the invention.  
         [0045]      FIG. 17A  is a generally perspective, exploded front view of the fluid flow control assembly shown in  FIG. 17 .  
         [0046]      FIG. 18  is a greatly enlarged, fragmentary cross-sectional view of one of the flow control channels formed in the flow control member shown in the central portion of  FIG. 17 .  
         [0047]      FIG. 19  is a generally perspective, rear view of the fluid flow control assembly of the apparatus of the invention.  
         [0048]      FIG. 20  is a generally perspective, exploded rear view of the fluid flow control assembly shown in  FIG. 19 .  
         [0049]      FIG. 21  is a generally perspective view of an alternate form of the flow control member of the invention.  
         [0050]      FIG. 21A  is a generally perspective view of yet another form of the flow control member of the invention.  
         [0051]      FIG. 22  is a front view of the assembly shown in  FIG. 19 .  
         [0052]      FIG. 23  is a cross-sectional view taken along lines  23 - 23  of  FIG. 22 .  
         [0053]      FIG. 24  is a view taken along lines  24 - 24  of  FIG. 23 .  
         [0054]      FIG. 25  is a cross-sectional view taken along lines  25 - 25  of  FIG. 23 .  
         [0055]      FIG. 26  is a cross-sectional view taken along lines  26 - 26  of  FIG. 23 .  
         [0056]      FIG. 27  is a generally perspective front view of an alternate embodiment of the medicament infusion apparatus of the present invention for dispensing fluids at a uniform rate.  
         [0057]      FIG. 28  is an enlarged, longitudinal cross-sectional view of the apparatus shown in  FIG. 27 .  
         [0058]      FIG. 29  is a left end a view of the alternate embodiment of the invention shown in  FIG. 27 .  
         [0059]      FIG. 30  is a right end view of the alternate embodiment of the invention shown in  FIG. 27 .  
         [0060]      FIG. 31  is a cross-sectional view taken along lines  31 - 31  of  FIG. 28 .  
         [0061]      FIG. 32  is a cross-sectional view taken along lines  32 - 32  of  FIG. 28 .  
         [0062]      FIG. 33  is a cross-sectional view taken along lines  33 - 33  of  FIG. 28 .  
         [0063]      FIG. 34  is a generally perspective, exploded view of the apparatus of the invention shown in  FIG. 28 .  
         [0064]      FIG. 35  is a fragmentary, cross-sectional view of a portion of the device housing showing the air collar and control shaft of the stored energy means of this latest form of the invention.  
         [0065]      FIG. 36  is an enlarged cross-sectional view taken along lines  36 - 36  of  FIG. 35 .  
         [0066]      FIG. 37  is a fragmentary cross-sectional view similar to  FIG. 35 , but showing the control shaft of the stored energy means moved into a second position.  
         [0067]      FIG. 38  is a cross-sectional view taken along lines  38 - 38  of  FIG. 37 .  
         [0068]      FIG. 39  is an enlarged fragmentary cross-sectional view showing the stored energy means of this latest form of the apparatus of the invention following completion of the fluid delivery step.  
         [0069]      FIG. 40  is an enlarged fragmentary cross-sectional view similar to  FIG. 39 , but showing the stored energy means of this latest form of the invention in an intermediate fluid delivery position.  
         [0070]      FIG. 41  is an enlarged, fragmentary cross-sectional view of the upper right hand portion of the apparatus shown in  FIG. 28 , better illustrating an alternate form of rate control assembly of the apparatus of this latest form of the invention.  
         [0071]      FIG. 42  is a generally perspective fragmentary, exploded view of the upper right hand portion of the apparatus shown in  FIG. 27 .  
         [0072]      FIG. 43  is a greatly enlarged, bottom perspective, exploded view of the rate control assembly of the apparatus of this latest form of the invention.  
         [0073]      FIG. 44  is a greatly enlarged, top perspective, exploded view of the rate control assembly of the apparatus of this latest form of the invention.  
         [0074]      FIG. 45  is a generally diagrammatic, tabular view illustrating and describing the various types of springs that can be used as the stored energy source of the invention.  
         [0075]      FIG. 46  is a generally diagrammatic, tubular view further illustrating and describing the various types of springs that can be used as the stored energy source of the invention. 
     
    
     DESCRIPTION OF THE INVENTION  
       [0076]     Referring to the drawings and particularly to  FIGS. 1 and 2 , one embodiment of the dispensing apparatus of the present invention is there illustrated and generally designated by the numeral  32 . The apparatus here comprises a moldable plastic outer housing  34  having a first, second and third portions  34   a ,  34   b  and  34   c  respectively. Disposed within outer housing  34  is a first, expandable housing  36  having a fluid reservoir  38  ( FIG. 15 ) provided with an inlet  40  for permitting fluid flow into the fluid reservoir and an outlet  44  for permitting fluid flow from the fluid reservoir. Expandable housing  36 , which can be constructed from a metal or plastic material, can include a coating of the character presently to be described. Expandable housing  36  here comprises a bellows structure having an expandable and compressible, accordion-like, annular-shaped sidewall  36   a , the configuration of which is best seen in  FIGS. 15 and 16 . The open end of the bellows is preferably sealably bonded to the device housing by an appropriate adhesive. Additionally, a sealing ring, such as ring  37   a , prevents fluid leakage between the bellows and the device housing ( FIG. 2 ).  
         [0077]     Disposed within second portion  34   b  of outer housing  34  is the novel, modulated stored energy means of the invention for acting upon inner expandable housing  36  in a manner to cause the fluid contained within fluid reservoir  38  to controllably flow outwardly of the housing. In the present form of the invention, this important stored energy means comprises a resiliently deformable, spring member  47  that is carried within the second portion  34   b  of the outer housing. In a manner presently to be described spring member  47  is controllably further compressed by fluid flowing into reservoir  38  and then is controllably expanded to cause fluid flow from the outer housing through the dispensing means of the invention. Stored energy member  47  can be constructed from a wide variety of materials including spring steel and plastic. In the preferred form of the invention, member  47  comprises a wave spring of the general type that is commercially available from various sources including the Smalley Company of Lake Zurich, Ill. However, as illustrated in  FIGS. 45 and 46 , and as will be discussed in greater detail hereinafter, several different types of springs can be used as the stored energy source of the invention.  
         [0078]     Frequently, wave springs operate as loading devices. They can also take up play and compensate for dimensional variations within mechanical assemblies. A virtually unlimited range of forces can be produced whereby loads build either gradually or abruptly to reach a predetermined working height. This establishes a precise spring rate in which load is proportional to deflection. Typically, a wave spring will occupy an extremely small area for the amount of work it performs and will operate within a known deflection range. The use of this type of spring product is demanded, but not limited to tight axial and radial space restraints.  
         [0079]     Forming an important aspect of the apparatus of the present invention is fill means carried by the third portion  34   c  of outer housing  34  for filling the reservoir  38  with the fluid to be dispensed. As best seen in  FIG. 2 , third portion  34   c  includes a fluid passageway  48  in communication with inlet  40  of fluid reservoir  38 . Proximate its lower end  48   a , fluid passageway  48  communicates with a cavity  50  formed within the third portion  34   c  of the housing. Disposed within cavity  50  is a pierceable elastomeric septum  52  that comprises a part of one form of the fill means and drug recovery of this latest form of the invention. Septum  52  is held in position by a suitably bonded retainer  52   a  and is pierceable by the needle of the syringe which contains the medicinal fluid to be dispensed and which can be used in a conventional manner to fill or partially fill reservoir  38  via passageway  48 . The fill and recovery means of the invention can also comprise a slit septum and a mechanical check valve system of a type well known to those skilled in the art.  
         [0080]     Third portion  34   c  of housing  34  also includes a chamber  55  for telescopically receiving a medicament containing closed-end shell fill vial  58 . An elongated support  60 , which is mounted within first chamber  55 , includes a threaded end portion  62  and carries a longitudinally extending, elongated hollow needle or cannula  64  having a flow passageway that communicates with fluid passageway  48 . Chamber  55 , elongated support  60  and hollow needle  64  together comprise an alternate form of the fill means of the apparatus of the invention. The method of operation of this alternate form of fill means will presently be described.  
         [0081]     Referring particularly to  FIG. 2 , the medicament containing plastic or glass shell fill vial  58  includes a body portion  66 , having a fluid chamber  68  for containing the injectable fluid medicament. Chamber  68  is provided with a first open end  68   a  and second closed end  68   b . First open end  68   a  is sealably closed by closure means here provided in the form of an externally threaded elastomeric plunger  70  which is telescopically movable within the vial from a first location where the plunger is disposed proximate first open end  68   a  to the second device-fill location shown in  FIG. 2  where the plunger is disposed proximate second closed end  68   b.    
         [0082]     After opening of the slidable vial closure  73 , which forms a part of the third portion  34   c  of housing  34  ( FIG. 10 ), vial  58  can be inserted into chamber  55 . As the fill vial is so introduced and the plunger  70  is threadably interconnected with end  60   a  of support  60 , the sharp end of the elongated needle  64  will pierce the central wall  70   a  of the elastomeric plunger. Continuous pushing movement of the vial into chamber  55  will cause the structural support to move the elastomeric plunger inwardly of the vial chamber  68  in a direction toward the second or closed end  68   b  of the vial chamber. As the plunger is moved inwardly of the vial, the fluid contained within the vial chamber will be expelled there from into the hollow elongated needle  64 . As best seen in  FIG. 2 , the fluid will then flow past elastomeric umbrella type check valve  76  and into a passageway  78  formed in third portion  34   c  of the apparatus housing. Umbrella type check valve  76  functions as a check valve to control fluid flow from the elongated hollow needle  64  toward fluid passageway  78 . From passageway  78  the fluid will flow into passageway  48  and then into reservoir  38  of the bellows component  36  via ullage filling channel or inlet  40 .  
         [0083]     As the fluid flows into the bellows reservoir, the bellows will be expanded from the collapsed configuration shown in  FIG. 2  into an expanded configuration (see  FIG. 15 ). As the bellows member expands it will urge a telescopically movable volume indicator member or engagement coupling  82  that is carried within a second portion  34   b  of the housing and in engagement with the stored energy source, or spring member  47  causing it to compress. It is also to be understood that, if desired, the reservoir of the bellows component can be filled with an adjuvant drug or other appropriate fluid by alternate filling means of the character previously described which comprises a syringe having a needle adapted to pierce the pierceable septum  52  which is mounted within third portion  34   c  of the apparatus housing. As the reservoir  38  fills with fluid either from the fill vial or from the filling syringe, any gases trapped within the reservoir will be vented to atmosphere via vent means “V” mounted in portion  34   b  of the ullage member. This vent means here comprises a bonded gas vent  83  that can be constructed of a suitable hydrophobic porous material such as a porous plastic. Gas vent  83  is held in position within the housing by a bonded retainer ring  83   a  ( FIG. 2 ).  
         [0084]     Upon opening the fluid delivery path to the administration set  84  of the invention ( FIG. 1 ) in a manner presently be described, the stored energy means, or member  47 , will tend to return toward its starting configuration thereby controllably urging fluid flow outwardly of reservoir  38  via the flow control means of the invention the character of which will presently be described.  
         [0085]     Administration set  84 , which forms a part of the dispensing means of the invention for dispensing fluid to the patient, is connected to the first portion  34   a  of housing  34  by a connector  84   a  in the manner shown in  FIG. 1  of the drawings. The proximal end  86   a  of administration line  86  of the administration set is in communication with an outlet fluid passageway  88  which is formed in housing portion  34   a  in the manner best seen in  FIG. 2 . Disposed between the proximal end  86   a  and the distal end  86   b  of the administration line is a conventional gas vent and particulate filter  90  and a conventional clamp  91 . Provided at the distal end  86   b  is a luer connector  92  and a cap  92   a  of conventional construction ( FIG. 1 ).  
         [0086]     As previously discussed, a number of liquid injectable beneficial agents can be contained within shell vial  58  and can be controllably dispensed to the patient including, by way of example, medicaments of various types, drugs, pharmaceuticals, hormones, antibodies, biologically active materials, elements, chemical compounds, or any other suitable material useful in diagnostic cure, midigation, treatment or preventing of diseases or the maintenance of the good health of the patient.  
         [0087]     As the fluid contained within the bellows reservoir  38  is urged outwardly thereof by the stored energy means, the fluid will flow into a fluid passageway  94  formed in the first portion  96   a  of an ullage member  96 . Ullage member  96  forms a part of the first portion  34   a  of the housing  34  and includes a first portion  96   a , which is housed within bellows  36 , and within which the bellows slidably cooperates ( FIG. 2 ). First portion  96   a  functions as a ullage member to ensure that substantially all of the residual fluid contained within the fluid reservoir is appropriately dispensed. The fluid will next flow under pressure through a filter means shown here as a filter  97  that is peripherally bonded with a cavity provided in the flow control member  100  of the flow control assembly  104 . Filter  97 , which functions to filter particulate matter from the fluid flowing outwardly from reservoir  38 , is of a character well known to those skilled in the art and can be constructed from various readily available materials such as polysolfone and polypropylene wafers having a desired porosity. After flowing through filter  97 , the fluid will flow, via a stub passageway  103  ( FIG. 2 ) into the novel flow control means of the invention that is disposed interiorly of housing  34 . This important flow control means functions to precisely control the rate of fluid flow outwardly from reservoir  38  and toward the patient.  
         [0088]     If the internal materials interface of the bellows structure and other fluid channels or surfaces are not sufficiently compatible with the planned beneficial agent to be delivered, either in terms of its biocompatibility or drug up-take characteristics, application of a surface modification process is appropriate. This surface modification methodology to provide a barrier coating “C” as shown in  FIG. 2A , may take one of several forms including single or multiple layer coatings. One process that is extremely clean, fast and efficient is plasma processing. In particular this technique allows for any of the following: plasma activation, plasma induced grafting and plasma polymerization of molecular entities on the internal drug surface of the bellows. For cases where an inert hydrophobic interface is desired, plasmas using fluorine-containing molecules may be employed. That is, the bellows surface as well as other surfaces or fluid passageways that may be contacted by the beneficial agent may be cleaned with an inert gas plasma, and subsequently, a fluorine-containing plasma may be used to graft these molecules to the surface. Alternatively, if a hydrophilic surface is desired (e.g. for drug solutions that are highly corrosive or in oil-based solvents) an initial plasma cleaning may be done, followed by a plasma polymerization using hydrophilic monomers.  
         [0089]     Referring to  FIGS. 17 through 26 , it can be seen that flow control assembly  104  comprises an outer casing  106  having a plurality of circumferentially spaced apart fluid outlets  108 , a flow control member  100 , which is telescopically receivable within casing  106  and a selector knob  112  that is interconnected with control member  100  in the manner best seen in  FIG. 23 . As illustrated in  FIGS. 17A and 20 , flow control member  100  is uniquely provided with a plurality of elongated, micro-fluidic flow control channels  114 , each having an inlet  114   a  and an outlet  114   b . The flow channels may be of different sizes, lengths, widths, depths and configurations as shown by  FIG. 21 , which depicts an alternate form of the flow control member having flow channels  115   a ,  115   b ,  115   c ,  115   d , and  115   e . The flow channels identified by the numerals  117   a  amd  117   b  in  FIG. 21A , which illustrates yet another form of flow control member of the invention, can be of still another configuration. Here the flow channels define circuitous flow paths in a plurality of individually, spaced-apart flow segments. Further, the flow control channels may be rectangular in cross-section as illustrated in  FIG. 18 , or alternatively, they can be semicircular in cross-section, U-shaped in cross-section, or they may have any other cross-sectional configuration that may be appropriate to achieve the desired fluid flow characteristics. The flow control channels may also be coated, if appropriate, with a coating “C” or alternate surface treatment (see  FIG. 11 ) of the character previously described herein. When the flow control member is properly positioned and bonded within outer casing  106 , the inner surface of the outer casing wall cooperates with channels  114  ( FIG. 20 ) to form a plurality of generally spiral shaped fluid flow passageways of different overall lengths and flow capacities. When the flow control member is positioned within the outer casing, a notch  100   b  formed in member  100  receives a tongue  106   a  provided on casing  106  so precisely align the outlets  114   b  of the flow channels  114  with fluid outlets  108  formed in casing  106 . It is to be understood, the suitable O-rings, generally designated as “O” are used to sealably interconnect the completed assembly (see  FIG. 19 ) to outer housing  96 .  
         [0090]     Selector knob  112 , which comprises a part of the selector means of the invention, is rotatably sealably connected to second portion  96   b  of ullage defining member  96  by means of an elastomeric band  113  and, in a manner presently to be described, functions to rotate the assembly made up of outer casing  106  and flow control member  100 . In this way, a selected outlet  108  in casing  106  can be selectively aligned with the flow passageway  88  provided in the ullage-defining member (see  FIG. 2 ).  
         [0091]     As previously discussed herein, as the fluid contained within the bellows reservoir  38  is urged outwardly thereof by the stored energy means, the fluid will flow into a fluid passageway  94  formed in the first portion  96   a  of an ullage member  96 . The fluid will next flow under pressure through filter  97  that is bonded within cavity  100   c  ( FIG. 20 ) provided in the flow control member  100  of the flow control assembly  104 .  
         [0092]     After flowing through filter  97 , the fluid will flow, via stub passageway  103  into the distribution means of the invention for distributing fluid from the fluid reservoir to each of the plurality of spiral passageways  114  ( FIG. 20 ). This distribution means here comprises several radially outwardly extending flow passageways  120  formed in flow control member  100  ( FIG. 25 ). The filtered fluid will fill passageways  120  and then will flow into the plurality of spiral passageways  114  via ports  114   a  formed in member  100  and then outlets  114   b , which communicate with passageways  114  (see  FIG. 20 ). The fluid contained within spiral passageways  114  can flow outwardly of the device only when one of the fluid outlets  108  formed in casing  106  is aligned with reservoir outlet passageway  88  ( FIGS. 2 and 19 ). A single apertured elastomeric sealing band  113  provides for rotating sealing between ullage  96  and housing  106 . As indicated in  FIG. 2 , the aperture provided in band  113  aligns with fluid passageway  88 .  
         [0093]     The flow control channels  114  can be made by several techniques including (micro) injection molding, injection-compression molding, hot-embossing and casting. The techniques used to make these imbedded fluid channels are now common-place in the field of microfluidics, which gave rise to the lab-on-a-chip, bio-MEMS and micro-total analysis systems (m-TAS) industries. Additionally, depending on the size of the fluid channels required for a given flow rate, more conventional micro injection molding techniques can be used.  
         [0094]     The first step in making the channels using an injection molding or embossing process is a lithographic step, which allows a precise pattern of channels to be printed on a “master” with lateral structure sizes down to 0.05 mm. subsequently, electroforming is performed to produce the negative metal form, or mold insert. Alternatively for larger chanel systems, precision milling can be used to make the mold insert directly. Typical materials for the mold insert or embossing tool are nickel, nickel alloys, steel and brass. Once the mold insert of embossing tool is fabricated, the polymer of choice may be injection molded or embossed to yield the desired part with imprinted channels.  
         [0095]     Alternatively, channels can also be made by one of a variety of casting processes. In general, a liquid plastic resin (e.g. a photopolymer) can be applied to the surface of a metal master (made by the techniques described above) and then cured via thermal of UV means. After hardening, the material is then “released” from the mold to yield the desired part. Additionally, there are similar techniques available that utilize CAD data (of the desired channel configuration) and direct laser curing of a liquid monomer to yield a polymerized and solidified part with imbedded channels. This process is available by contract, for example, for MicroTEC MbH of Duisburg, Germany.  
         [0096]     A number of materials can be used to fabricate flow control member  86 . While medical grade polymers are the most appropriate materials, other materials can be used including: Thermoplastics (embossing &amp; injection molding); Duroplastics (injection molding); Elastomers (injection compression molding and soft lithography); Polyurethanes (castings); and Acrylics and Epoxies. U.S. Pat. No. 6,176,962 and WO 99/5694 disclose various techniques for making micro-fluidic flow channels  
         [0097]     Selection of the passageway  114  from which the fluid is to be dispensed is accomplished by rotation of the selector knob  112  which, as best seen in  FIGS. 20 and 23  includes a reduced diameter portion  112   a  having a slot  112   b  formed therein. As illustrated in  FIGS. 17A and 26 , slot  112   b  is adapted to receive a spline  123  ( FIG. 17A ) formed anteriorly of member  100 . With this construction, rotation of selector member  112  by gripping a transversally extending finger grip ping member  25  will impart part rotation to member  112 . As seen in  FIG. 20 , inwardly extending spline segment  106   a  is received within slot  100   b  formed in the rearward periphery of member  100 . Accordingly, rotation of member  112  will also impart concomitant rotation to casing member  106 .  
         [0098]     As illustrated in  FIGS. 20 and 26 , selector knob  112  is provided with a plurality of circumferentially spaced apart indexing cavities  127  that closely receive an indexing finger  130  which forms a part of the indexing means of the invention, which means comprises a locking shaft cover  129  that is connected to third portion  34   c  of the apparatus housing (see  FIGS. 2 and 5 ). Indexing finger  130  is continuously urged into engagement with a selected one of the indexing cavities  127  by a coil spring  134  that also forms a part of the indexing means of the invention. Coil spring  134  can be compressed by an inward force exerted on an indexing shaft  136  that is mounted in locking shaft cover  129  and is movable from the extended position shown in  FIG. 2  to an inward, finger release position wherein spring  134  is compressed and finger  130  is retracted from a selected indexing cavity  127 . With finger  130  in its retracted position it is apparent that control knob  112  can be freely rotated to a position wherein gripping member  25  can be aligned with selected flow rate indicia  135  formed on the front bezel  129  of the apparatus housing ( FIG. 1 ).  
         [0099]     When the selector knob is in the desired position and pressure is released on indexing shaft  136 , spring  134  will urge finger  130  of the indexing means of the invention into locking engagement with one of the indexing cavities  127  thereby placing a selected one of the spiral shaped flow control channels  114  in communication with the fluid reservoir  38  via passageways  44 ,  103  and  120 . As the fluid flows outwardly of the apparatus due to the urging of the stored energy means or spring member  47 , the bellows structure  36  will be collapsed and at the same time coupling member  82  will travel inwardly of housing portion  34   b . Member  82 , which forms a part of the volume indicator means of the invention, includes a radially outwardly extending indicating finger  82   a  that is visible through a volume indicator window  139  that is provided in a second portion  34   b  of the apparatus housing and also comprises a part of the volume indicator means of the invention ( FIGS. 1 and 2 ). Indicia  141 , which are provided on indicator window  139 , function to readily indicate to the caregiver the amount of fluid remaining within fluid reservoir  38 . Referring to  FIG. 3 , disabling means, shown here as a disabling shaft  144  that is telescopically movable within a passageway  146  formed within housing portion  34   a  functions to disable the device. More particularly, shaft  144  has a distal end  144   a , which, upon insertion of the shaft, will block fluid flow through passageway  88 . A bonded retainer  144   b  normally holds shaft  144  in the retracted position.  
         [0100]     Considering next the important modulating means of the invention for modulating the force exerted upon inner expandable housing  36  by the stored energy means, or spring  47 . In the present form of the invention this modulating means comprises a second expandable housing  150  that is carried by outer housing  34  and is operably associated with first expandable housing  36 . Second expandable housing comprises a bellows structure having an accordion like sidewall  150   a  that defines a fluid chamber  153  for containing a fluid such as air. Second expandable housing  150 , which has an outlet  155  for permitting the flow of air there through, is movable from the substantially expanded configuration shown in  FIG. 2  to the substantially collapsed configuration shown in  FIG. 16 , by a force exerted thereon by spring member  47 . The modulating means of the present form of the invention further includes impedance means, here provided as an impedance porous frit  154 , that is disposed within fluid outlet  155 , for controllably impeding the flow of the fluid contained within fluid chamber  153  outwardly thereof to atmosphere via a flow passageway  156  formed in second housing portion  34   b  and a vent V- 1 .  
         [0101]     Disposed between spring  47  and second bellows housing  150  is an air collar  158  that is slidably movable within housing  34  along upper and lower, longitudinally extending shafts  160  and  162  (see  FIGS. 15 and 16 ). During the medicament delivery step, spring  47  acts upon indicator member  82 , which, in turn acts upon first bellows assembly  36  tending to collapse it and to cause the medicinal fluid contained within reservoir  38  to be forced outwardly thereof via reservoir outlet  44 . At the same time, spring  47  acts upon air collar  158  which, in turn, acts upon second to bellows  150  tending to collapse it. However, before air collar  158  can slidably move along control shafts  160  and  162 , the air collar must be released from its normally locked position shown in  FIGS. 11 and 12  of the drawings. As indicated in  FIGS. 11 and 12 , sliding movement of air collar  158  is normally prevented by locking means shown here as a stop tab  164  that engages a shoulder  166  formed on control rod  160 . At the commencement of the medicament delivery step, control rod  160  is rotated by gripping the finger grip portion  160   a  thereof. As indicated in  FIGS. 13 and 14 , when the control shaft  160  is controllably rotated, the stop tab  164  to ride up on the shaft and out of locking engagement with shoulder  166  allowing the air collar to move rearwardly of the control shaft in the manner illustrated in  FIG. 14 .  
         [0102]     Rearward movement of the air collar due to the urging of spring  47 , in the manner illustrated in  FIG. 15 , will cause the air within chamber  153  of the second bellows assembly  150  to controllably flow through porous frit  154 , which is appropriately tuned to the particular spring constant, and outwardly to atmosphere via the vent V- 1 . As the air collar moves rearwardly of the housing, it is apparent that the force being exerted on first bellows  36  by spring  47  will be modulated. As shown in  FIG. 16A  of the drawings, this modulation of the force exerted by spring  47  on second bellows  36  uniquely results in a more linear flow of medicinal fluid outwardly of the device as depicted in the lower-most graph of  FIG. 16A . More particularly, as shown in the upper-most graph of  FIG. 16A , the greater the compression on the spring, the greater will be the force generated by the spring. Accordingly, at the beginning of the fluid delivery cycle, when the spring is highly compressed, the force generated by the spring will be greater than the force generated as the spring relaxes and approaches the end of the fluid delivery cycle. This spring unloading, unless compensated for, will result in a greater fluid flow at the beginning of the fluid delivery cycle and a lesser fluid flow toward the end of the delivery cycle. Second bellows assembly  150  of the modulating means functions to compensate for this undesirable condition. More particularly, as the second bellows, is compressed by the spring in the manner shown in  FIGS. 15 and 16 , the second bellows assembly  150  functions to counter act, or modulate the greater force generated by the spring during the early portion of the flow delivery cycle. This novel modulating action as depicted in the lower-most graph of  FIG. 16A , results in the vastly improved constant flat linear flow of the medicinal fluid outwardly of the apparatus. When all of the medicinal fluid has been delivered from the fluid reservoir  38 , spring  47  will have expanded into the configuration shown in  FIG. 16  and both of the first and second bellows assemblies  36  and  150  will have been fully collapsed. As shown in  FIG. 28 , a suitable seal ring  151  is provided to prevent leakage between the bellows and housing portion  194 .  
         [0103]     Referring now to  FIGS. 27 through 44 , another embodiment of the dispensing apparatus of the present invention is there illustrated and generally designated by the numeral  170 . This alternate form of the apparatus of the invention is similar in many respects to that shown in  FIGS. 1 through 26  and like numerals are used in  FIGS. 27 through 44  to identify like components. The primary differences between this latest form of the invention and that shown in  FIGS. 1 through 26  concern the provision of a differently configured flow rate control means for controlling the rate of fluid flow from the apparatus and the provision of a differently designed control mechanism for controlling the flow of fluid outwardly of the second bellows assembly of the apparatus. More particularly, this alternate form of control mechanism is operable from the rear of the apparatus rather than from the front. Additionally, as will be better understood from the discussion, which follows, this latest embodiment of the invention includes a plurality of flow control, porous frits that are strategically positioned relative to the second bellows to control fluid flow from the second bellows.  
         [0104]     As best seen by referring to  FIGS. 27 and 28 , the apparatus of this latest form of the invention comprises an outer housing  172  having a first, second and third portions  172   a ,  172   b  and  172   c  respectively. Disposed within outer housing  172  is a first, expandable housing  36 , which is a similar construction to that previously described and includes a collapsible bellows like structure that defines a fluid reservoir  38 . As before, reservoir  38  is provided with an inlet passageway  176  for permitting fluid flow into the fluid reservoir and an outlet  178  for permitting fluid flow from the fluid reservoir.  
         [0105]     Disposed within second portion  172   b  of outer housing  172  is the modulated stored energy means of the invention for acting upon first expandable housing  36  in a manner to cause the fluid contained within fluid reservoir  38  to controllably flow outwardly of the housing. In this latest form of the invention, this important stored energy means is generally similar to that previously described and comprises a compressively deformable, spring member  47  that is carried within the second portion  172   b  of the outer housing. As before, spring member  47  is first compressed by fluid flowing into reservoir  38  and then is controllably expanded to cause fluid flow from the outer housing through the dispensing means of the invention.  
         [0106]     As in the earlier described embodiment of the invention, fill means are carried by the third portion  172   c  of outer housing  172  for filling the reservoir  38  with the fluid to be dispensed. In this regard, third portion  172   c  includes a fluid passageway  180  in communication with inlet passageway  176  of fluid reservoir  38 . Proximate its lower end  180   a , fluid passageway  180  communicates with a cavity  182  formed within the third portion  172   c  of the housing. Disposed within cavity  182  is an elastomeric, pierceable septum  184  that comprises a part of one form of the fill means of this latest form of the invention. Septum  184  is held in position by a retainer  184   a  and is pierceable by the needle of the syringe which contains the medicinal fluid to be dispensed and which can be used in a conventional manner to fill or partially fill reservoir  38  via passageway  180 .  
         [0107]     Third portion  172   c  of housing  172  also includes a chamber  185  for telescopically receiving a medicament containing fill vial  58 , which is identical in construction and operation to that previously described, as is the elongated support  60 , which is mounted within first chamber  55 . Chamber  55 , elongated support  60  and hollow needle  64  together comprise an alternate form of the fill means of the apparatus of this latest form of the invention.  
         [0108]     During the reservoir filling step in the manner previously described, as the elastomeric plunger is moved inwardly of the vial, the fluid contained within the vial chamber will be expelled there from into the hollow elongated needle  64 . As best seen in  FIG. 28 , the fluid will then flow past umbrella type check valve  76  and into a passageway  187  formed in third portion  172   c  of the apparatus housing. Umbrella type check valve  76  functions to control fluid flow from the elongated hollow needle  64  toward fluid passageway  187 . From passageway  187  the fluid will flow into passageway  180  and then into reservoir  38  of the bellows component  36  via inlet passageway  176  and a suitable filter  177 . Any gas is contained within the fill vial can be vented to atmosphere and via a vent “V- 3 ”.  
         [0109]     As the fluid flows into the bellows reservoir, the bellows will be expanded from a collapsed configuration into an expanded configuration shown in  FIG. 28 . As the bellows member expands it will urge a telescopically movable volume indicator member  82  that is carried within a second portion  172   b  of the housing into engagement with the stored energy source, or spring member  47  causing it to compress. It is also to be understood that, if desired, the reservoir of the bellows component can also be filled by alternate filling means of the character previously described which comprises a syringe having a needle adapted to pierce the pierceable septum  184  which is mounted within third portion  172   c  of the apparatus housing. As the reservoir  38  fills with fluid either from the fill vial or from the filling syringe, any gases trapped within the reservoir will be vented to atmosphere via vent means “V- 3 ” that is mounted in portion  190   b  of an ullage member  190 . This vent means here comprises a gas vent  83  that can be constructed of a suitable hydrophobic porous material such as a porous plastic. Gas vent  83  is held in position within the housing by a retainer ring  83   a  ( FIG. 28 ).  
         [0110]     Upon opening the fluid delivery path to the administration set  84  of the invention ( FIG. 27 ), which is identical to that previously described, the stored energy means, or member  47 , will tend to return to its starting configuration thereby controllably urging fluid flow outwardly of reservoir  38  via the flow control means of the invention the character of which will presently be described.  
         [0111]     As the fluid contained within the bellows reservoir  38  is urged outwardly thereof by the stored energy means, the fluid will flow into an outlet passageway  192  and then into a stub passageway  194  formed in portion  190   b  of the ullage member  190 . Ullage member  190  includes, in addition to portion  190   b , a second portion  190   a  that is housed within bellows  36  ( FIG. 28 ). After flowing into stub passageway  194 , the medicinal fluid will flow into the novel flow control means of the invention that is disposed within ullage portion  190   b . This important flow rate control means functions to precisely control the rate of fluid flow outwardly from reservoir  38  and toward the patient.  
         [0112]     Referring to  FIGS. 28, 41 ,  42 ,  43  and  44 , it can be seen that the flow rate control means here comprises a rate control assembly  198  that is housed within a cavity  198   a  formed in ullage portion  190   b . As best seen in  FIGS. 43 and 44 , this novel rate control assembly comprises an inlet manifold  202  having an inlet port  204  that is in communication with an outlet manifold  206  that is interconnected with intake manifold  202  by means of a separator plate  208 . As indicated in  FIGS. 28 and 44 , outlet manifold  206  as an outlet port  206   a  that is in communication with administration line  86  of the administration set  84 . As shown in  FIG. 43 , outlet manifold  206  is provided with an elongated micro channel  210  that is in communication both with inlet port  204  and with outlet port  206   a  of the outlet manifold. It is to be understood that, while micro fluidic channel is here shown in a spiral configuration, it can be provided in a number of different types of configurations and, if desired, can be appropriately coated. Disposed intermediate inlet manifold  202  and the generally circular shaped separator plate  208  is filter means here provided as a filter member  212  that functions to filter fluid flowing toward outlet port  206   a  of the outlet manifold. Generally disk shaped filter member  212  can be formed from various porous materials, including porous metals and porous ceramics.  
         [0113]     As best seen in  FIG. 43 , separator plate  208  is provided with standoff ribs  214  for supporting filter member  212 . The assemblage made up of inlet manifold  202 , outlet manifold  206 , separator plate  208  and filter  212  is encapsulated within housing cavity  198   a  in the manner shown in  FIG. 28 .  
         [0114]     As indicated in  FIG. 43 , the flow rate control means, or assemblage  198 , has an axial centerline “C” with which the inlet port  204  of the inlet manifold  202  is coaxial aligned. However, the outlet port  206   a  of the outlet manifold  206  is radially spaced from the axial centerline. With this construction, fluid will flow from reservoir  38  into inlet port  204 , through filter member  212 , through a central opening  208   a  formed in separator plate  208  and thence into micro channel  210 . By controlling the length and depth of the micro channel  210 , the rate of fluid flow flowing outwardly of outlet  206   a  can be precisely controlled. In this regard, the micro channel can take several forms and is not limited to the configuration shown in  FIG. 43  of the drawings.  
         [0115]     Turning once again to  FIG. 27 , the dispensing means for dispensing fluid to the patient comprises the previously identified administration set  84  that is connected to the first portion  172   a  of housing  172  in the manner shown in the drawings. As previously discussed, a number of beneficial agents can be controllably dispensed to the patient including, by way of example, medicaments of various types, drugs, pharmaceuticals, hormones, antibodies, biologically active materials, elements, chemical compounds, or any other suitable material useful in diagnostic cure, medication, treatment or preventing of diseases or the maintenance of the good health of the patient.  
         [0116]     During the fluid delivery step, as the fluid flows outwardly of the apparatus due to the urging of the stored energy means or spring member  47 , the bellows structure  36  will be collapsed and at the same time member  82  will travel inwardly of housing portion  172   b . Member  82 , which forms a part of the volume indicator means of the invention, includes a radially outwardly extending indicating finger  82   a  that is visible through a volume indicator window  139  that is provided in a second portion  172   b  of the apparatus housing and also comprises a part of the volume indicator means of the invention ( FIGS. 27 and 28 ). Indicia  141 , which are provided on indicator window  139 , function to readily indicate to the caregiver the amount of fluid remaining within fluid reservoir  38 .  
         [0117]     Referring to  FIG. 42 , disabling means of the same construction and operation as that previously discussed in connection with the first embodiment of the invention are provided to disable the device. More particularly, shaft  144  has a distal end  144   a , which, upon insertion of the shaft, will block fluid flow through passageway  194  and toward the previously described rate control assembly  198 . As before, retainer  144   b  normally holds shaft  144  in the retracted position.  
         [0118]     Considering next the important modulating means of this latest form of the invention for modulating the force exerted upon inner expandable housing  36  by the stored energy means, or spring  47 . The modulating means in this latest form of the invention is similar in construction and operation to that previously described and here comprises a second expandable housing  220  that is carried by outer housing  172 . Second expandable housing  220 , which is operably associated with first expandable housing  36 , comprises a bellows structure having an accordion like sidewall  220   a  that defines a fluid chamber  223  for containing a fluid such as air. Second expandable housing  220 , which has an outlet  225  for permitting the flow of air there through, is movable from the substantially expanded configuration shown in  FIG. 28  to the substantially collapsed configuration shown in  FIG. 39 , by a force exerted thereon by spring member  47 .  
         [0119]     The modulating means of the present form of the invention further includes impedance means, here provided as a plurality of circumferentially spaced impedance frits  226   a ,  226   b ,  226   c  and  226   d  which are mounted within a control knob  228  that is rotatably carried proximate back of the drive by housing portion  172   b  (see  FIGS. 29 and 32 ). These impedance frits, which can be constructed with different porosity, can be moved into index with bellows outlet  225  by controllably rotating control knob  228 . In this way, the rate at which the fluid, such as air, will flow from reservoir  223  of bellows  220  to atmosphere via a selected frit can be controllably varied.  
         [0120]     Disposed between spring  47  and second bellows housing  220  is an air collar  231  that is slidably movable within housing  172  along longitudinally extending shafts  234  and  236  (see  FIGS. 28, 35  and  36 ). During the medicament delivery step, spring  47  acts upon indicator member  82 , which, in turn, acts upon first bellows assembly  36  tending to collapse it and to cause the medicinal fluid contained within reservoir  38  to be forced outwardly thereof via reservoir outlet  178 . At the same time, spring  47  acts upon an air collar  231  which, in turn, acts upon second bellows  220  tending to collapse it. However, before air collar  231  can slidably move along control shafts  234  and  236 , the air collar must be released from its normally locked position shown in  FIGS. 35 and 36  of the drawings. As indicated in  FIGS. 35 and 36 , sliding movement of air collar  231  is normally prevented by locking means shown here as a stop tab  238  that engages a shoulder  240  formed on rod  234 . At the commencement of the medicament delivery step, control rod  234  is rotated by rotating the rearwardly mounted control knob  228 . As illustrated in  FIG. 34 , control knob  228  is provided with a plurality of driving teeth  228   a  that engage driven teeth  242  provided proximate the end of control rod  234 . With this construction, rotation of control knob  228  causes rotation of control shaft  234  which, in turn, causes the stop tab  238  to ride up on the shaft and out of locking engagement with shoulder  240  in the manner shown in  FIG. 37  thereby allowing the air collar to move rearwardly of the control shaft in the manner shown in  FIG. 38 .  
         [0121]     Rearward movement of the air collar due to the urging of spring  47 , as illustrated in  FIG. 28 , will cause the air within chamber  223  of the second bellows assembly  220  to controllably flow through the selected porous frit that is in index with outlet  225  and then outwardly to atmosphere via the selected frit. As earlier described herein and as illustrated by  FIG. 16A  of the drawings, as the air collar moves rearwardly of the housing, the force being exerted on first bellows  36  by spring  47  will be modulated. As before, this modulation of the force exerted by spring  47  on second bellows  220  uniquely results in a more linear flow of medicinal fluid outwardly of the device as depicted by the lower graph of  FIG. 16A .  
         [0122]     Referring once again to  FIGS. 45 and 46 , the various types of springs suitable for use as the stored energy source of the invention are there illustrated and described. By way of background, springs are unlike other machine/structure components in that they undergo significant deformation when loaded—their compliance enables them to store readily recoverable mechanical energy.  
         [0123]     With respect to the specific spring configurations shown in  FIGS. 45 and 46 , the following discussion amplifies the descriptive notations in these drawings.  
         [heading-0124]     Compression Springs:  
         [0125]     Compression springs are open-wound helical springs that exert a load or force when compressed. They may be conical or taper springs, barrel or convex, concave or standard cylindrical in shape. The ends can be closed and ground, closed but unground, open and unground and supplied in alternate lengths. They also can include a configuration where a second compression spring of similar or different performance characteristics which can be installed inside the inside diameter of their first compression spring, i. e., a spring in a spring.  
         [0126]     Many types of materials can be used in the manufacture with compression springs including: Commercial Wire (BS5216 HS3), Music Stainless Steel, Phosphur Bronze, Chrome Vanadium, Monel 400, Inconel 600, Inconel X750, Nimonic 90: Round wire, Square and Rectangular sections are also available. Exotic metals and their alloys with special properties can also be used for special and applications; they include such materials as beryllium copper, beryllium nickel, niobium, tantalum and titanium.  
         [0127]     Compression springs can also be made from plastic including all thermoplastic materials used by custom spring winding service providers. Plastic springs may be used in light-to-medium duty applications for quiet and corrosion-resistant qualities.  
         [heading-0128]     Wave Spring:  
         [0129]     Multiwave compression springs, an example of which is shown as “F” in  FIG. 19B  are readily commercially available from sources, such as the Smalley Company of Lake Zurich, Ill. As previously discussed, such springs operate as load bearing devices. They can take up play and compensate for dimensional variations within assemblies. A virtually unlimited range of forces can be produced whereby loads built either gradually or abruptly to reach a predetermined working height. This establishes a precise spring rate in which load if proportional to deflection, and can be turned to a particular load requirement.  
         [0130]     Typically, a wave spring will occupy an extremely small area for the amount of work it performs. The use of this product is demanded, but not limited to tight axial and radial space restraints; one or more disc springs can be used and also of alternate individual thicknesses. Alternate embodiments of the basic disc spring design in a stacked assembly can be also utilized including specialty disc spring similar to the Belleville configuration called K Disc Springs manufactured by Adolf Schnorr BM8H of Singelfingen, Germany, as well as others manufactured by Christian Bauer GMBH of Welzheim, Germany.  
         [heading-0131]     Disc Springs:  
         [0132]     Disc springs, examples of which are shown in G through P in  FIGS. 45 and 46  comprise conically shaped annular discs (some with slotted or fingered configuration) which when loaded in the axial direction, change shape. In comparison to other types of springs, disc springs product small spring deflections under high loads. Some examples of the disc-shaped compression springs include a single or multiple stacked Belleville washer configuration as shown in G and H of  FIG. 45 , and depending on the requirements of the design (flow rate over time including bolus opportunity) one or more disc springs can be used and also of alternate individual thicknesses. Alternate embodiments of the basic disc spring design in a stacked assembly can be also utilized including specialty disc springs similar to the Belleville configuration called K disc springs manufactured by Adolf Schnorr GM8H of Singelfingen, Germany, as well as others manufactured by Christian Bauer GMBH of Welzheim, Germany.  
         [0133]     Disc springs combine high energy storage capacity with low space requirement and uniform annular loading. They can provide linear or nonlinear spring loadings with their unique ability to combine high or low forces with either high or low deflection rates. They can be preloaded and under partial compression in the design application.  
         [0134]     All these attributes, and more, come from single-component assemblies whose nontangle features (when compared to wirewound, compression springs) make them ideal for automatic assembly procedures.  
         [0135]     With respect to the various springs discussed in the preceding paragraphs, it is to be understood that many alternate materials can be used in the design and application of disc springs and include carbon steel, chrome vanadium steel, stainless steel, heat resistant steels, and other special alloys such as nimonic, inconel, and beryllium copper. In some special applications, plastic disc springs designs can be used.  
         [0136]     It should be further observed that, in comparison to other types of springs, disc springs produce small spring deflections under high loads. The ability to assemble disc springs into disc spring stacks overcomes this particular limitation. When disc springs are arranged in parallel (or nested), the load increases proportionate to the number of springs in parallel, while when disc springs are arranges in series (alternately) the travel will increase in proportion to the number of springs serially arranged. These assembly methods may be combined in use.  
         [0137]     One special feature of the disc spring is, undoubtedly, the fact that the load/deflection characteristic curve can be designed to produce a wide variety of possibilities. In addition to practically linear load/deflection characteristic curves, regressive characteristics can be achieved and even disc springs which exhibit increasing spring deflection while the corresponding disc spring load is decreasing are readily available.  
         [0138]     Slotted disc springs present a completely different case. Slotting changes the load/deflection characteristic of the single disc spring, providing larger spring deflections for greatly reduced loads. The slotted part is actually functioning as a series of miniature cantilever arms. In some cases the stacked, slotted disc spring, as shown in the clover dome design, will also produce a non-linear, stress strain curve with a noticed flat region (force/deflection). Application and use of this type of spring operating in this region will provide a near constant force between 15% and 75% of compression.  
         [0139]     Having now described the invention in detail in accordance with the requirements of the patent statutes, those skilled in this art will have no difficulty in making changes and modifications in the individual parts or their relative assembly in order to meet specific requirements or conditions. Such changes and modifications may be made without departing from the scope and spirit of the invention, as set forth in the following claims.