Fluid dispenser

A portable device is provided for dispensing fluid in a controlled manner, and, optionally, for mixing two or more fluid components prior to dispensing the resulting mixture. The device comprises a modified syringe provided with needle valve and associated cannula through which fluid is drawn into the syringe chamber and expelled therefrom in a controlled manner by appropriate movement of the piston. In a particular embodiment propellant gas is released behind the piston which, in sealing slidable engagement with the syringe cylinder, thereby exerts expelling pressure on the fluid in the cylinder chamber. The rate of expulsion of fluid from the chamber is regulated by adjustment of the needle valve. The device is especially adapted for mixing two or more liquid components of a periodontal composition and for controlled dispensing of the resulting composition at the locus to be treated.

BACKGROUND OF THE INVENTION 
(1) Field of the Invention 
This invention relates to the dispensing of fluids and is more particularly 
concerned with an apparatus and method for mixing two or more fluids and 
dispensing the mixture in a controlled manner. 
(2) Description of the Prior Art 
It is desirable to dispense fluid from a relatively inexpensive package 
which may be disposable after use or which may be recoverable for re-use. 
In some applications it is desirable to be able to mix fluids from two or 
more separate containers and then dispense the mixed fluids. This is 
particularly the case with two or more fluids which may be chemically 
reactive or unstable when stored in admixture for a prolonged period and 
which must be dispensed very soon after mixing. A typical situation is 
that posed by periodontal applications where it is desirable to mix two 
incompatible chemicals as disclosed in U.S. Pat. No. 4,521,403. 
A typical device for dispensing fluids from a plurality of containers is 
disclosed in McCulloch, U.S. Pat. No. 3,613,956. The latter discloses two 
aerosol dispensing containers having hollow stems displaceable to 
discharge fluid under pressure. The actuating mechanism is a handle which 
pulls the valve stems inward toward their respective containers. The 
valves are manually pulled inwardly by a trigger which is returned to its 
original position when it is no longer desired to dispense fluid from the 
aerosol containers. One of the primary disadvantages of a system that 
contains aerosol valves that may be repeatedly opened and closed is that 
the fluid in the containers is not completely dispensed in one actuation 
of the valves. Since the pressures and the flow rates through the valves 
may differ from container to container depending upon the type of fluid 
being dispensed, the size of the valves, and the pressure in the 
container, the materials may be mixed in undesirable proportions. In 
addition, if the containers have equal pressures, but the flow rate 
through the respective valves is different, the head pressure in the 
mixing chamber may rise to a level where it prevents flow from one of the 
containers. Thus, the liquids will not be mixed in the desired 
proportions. 
As well as the above disadvantages this type of device suffers the serious 
problem of bulk which requires the operator to utilize both hands in the 
dispensing mode. Thus, one hand has to be utilized to actuate and maintain 
liquid flow and the other hand is utilized to direct the liquid being 
dispensed to the locus to be treated. 
It is accordingly highly desirable to provide a device which will not only 
mix and dispense fluids but which is of such size and mode of operation as 
to be held in one hand by an operator and to continue to dispense fluid to 
the locus to be treated at a controlled rate after actuation without 
further manual manipulation of the actuating mechanism. 
SUMMARY OF THE INVENTION 
It is an object of the invention to provide a device for dispensing fluid 
in a controlled manner without the continuous application of manual 
pressure by the operator to maintain fluid flow. 
It is a further object of the invention to provide a device for dispensing 
fluid in a controlled manner, which device can be held in one hand by the 
operator while the fluid being dispensed is directed to a desired 
location. 
It is yet another object of the invention to provide a device which can be 
utilized to mix two or more fluids and dispense the resulting mixture in a 
controlled manner without continuous application of manual pressure by the 
operator to maintain fluid flow. 
These objects, and other objects which will become apparent from the 
description which follows, are achieved by the apparatus and process of 
the present invention. 
In accordance with one aspect of the present invention a fluid dispensing 
device is provided comprising a piston slidably mounted in a cylinder and 
defining therewith a chamber for receiving fluid to be dispensed. Valve 
means, preferably needle valve means, is provided for controlling passage 
of fluid into and out of said chamber at a controlled rate. Passage of 
fluid into the chamber is achieved by withdrawing the piston and drawing 
fluid into the chamber from a source of fluid advantageously through a 
cannula or like tube associated with the valve means. Dispensing of fluid 
from the chamber is achieved by providing means for releasing propellant 
gas under pressure to bias said piston into said chamber. Manual means is 
provided for actuating release of the propellant gas. This means requires 
manual operation to commence release of the gas but does not require 
constant manual pressure throughout the fluid dispensing operation. 
In accordance with a preferred aspect of the invention the piston of the 
device is hollow and has a plunger detachably mounted therein. A container 
having valve means for dispensing propellant gas under pressure is 
slidably mounted within the plunger. The valve means on the container is 
normally biased to a closed position. The container is mounted in the 
plunger in a manner such that the end portion of the stem of the valve 
means is received in an appropriately sized and shaped passageway which 
precludes longitudinal movement of the valve stem relative to the 
passageway and which terminates in an orifice opening into the interior of 
the hollow piston. Actuating means is provided for moving the container 
longitudinally in the plunger which movement causes the valve stem, which 
is estopped from longitudinal movement in the above passageway, to be 
depressed and pressurized gas to be released. In order to commence 
dispensing of fluid from the device, means are provided for detaching the 
hollow piston from the plunger and means are also provided for locking the 
plunger in a fixed fluid sealing engagement with the cylinder. When both 
of these means have been activated the means for release of pressurized 
gas is actuated. The gas serves to bias the hollow piston into the chamber 
containing fluid. Controlled dispensing of the fluid is achieved by 
appropriate manipulation of the valve means on the cylinder. 
Where the device is to be used to mix two or more fluids in accurately 
measured proportions the device is provided with appropriate and visible 
graduation. The graduation is on the exterior of the cylinder if the 
latter is sufficiently transparent to reveal the level of liquid contained 
in the chamber or, alternatively, is on the exterior of the portion of the 
plunger which is withdrawn from the cylinder as fluid is drawn into the 
chamber. 
Stop means can also be provided for limiting the distance through which the 
plunger can be withdrawn from the cylinder during the fluid filling 
operations. Preferably the exterior contour of the portion of the piston 
received in the cylinder when the plunger is fully inserted therein 
conforms substantially to the interior contour of the cylinder. The 
ultimate substantially complete elimination of fluid from the chamber is 
thereby assured.

DETAILED DESCRIPTION OF THE INVENTION 
Referring now to the drawings, FIG. 1 shows a cross-sectional view taken 
along the longitudinal axis of a fluid dispensing device, shown generally 
as 2. Cylinder 4 has slidably mounted therein hollow piston 6 which is 
detachably retained in sleeve-like fashion on the end of plunger 8 by 
means of interaction of male threads 10 disposed on the exterior of the 
outer end of passageway 12 and female threads 14 disposed on the interior 
of throat 16. Annular projection 18 on the outer perimeter of piston 6 
engages corresponding annular projection 20 disposed on the inner wall of 
the upper end of cylinder 4 to prevent accidental withdrawl of piston 6 
and attached plunger 8 beyond the position shown in FIG. 1. Step 22 on the 
wall of plunger 8 receives the rim of the upper end of piston 6 in 
abutting relationship when the piston is mounted in fixed position on the 
plunger. The plunger 8 projects outwardly from the upper end of cylinder 4 
through the threaded collar 26 and in sliding engagement with the inwardly 
projecting rim 24 on the upper end of cylinder 4. Collar 26 is threadedly 
mounted on the end of cylinder 4 and can be tightened by manual rotation 
in the appropriate direction to lock the plunger 8 in fixed sealing 
engagement with the cylinder 4 by compression of the O-ring 28 between the 
abutting surfaces of the underside of collar 26 and the top rim of 
cylinder 4. 
The outer end of plunger 8 projects outwardly from the cylinder 4, in the 
view shown in FIG. 1, and terminates in skirted flange 30 the underside 32 
of which is spaced apart from the outer wall of plunger 8 a distance such 
that the skirted flange 30 can overlap the collar 26 when the plunger and 
attached piston 6 are displaced completely into cylinder 4. 
Propellant gas container 34 is slidably mounted within plunger 8 with valve 
stem 36 received in appropriately sized passageway 38 in the throat of 
said plunger 8. Valve stem 36 is normally biased to the closed position as 
shown in FIG. 1 but is movable inwardly into the container 34 against the 
bias to an open position. The tip 40 of valve stem 36 is in abutting, 
arresting relationship with orifice 42. Displacement of container 34 
longitudinally inwardly in said plunger 8 causes the valve stem 36, which 
is not free to move longitudinally because of interference with orifice 
42, to be moved inwardly into the container to the open position. 
Actuating knob 44 is mounted in the outer end of plunger 8 with inner end 
46 in abutting relationship with bottom 50 of container 34. Knob skirt 48 
on knob 44 is in frictional sliding engagement with the inner wall of 
plunger 8. Annular bead 52 on actuating knob 44 and corresponding annular 
beads 54 and 56 on the inner wall of plunger 8 serve to define and limit 
the distance through which knob 44 can be moved longitudinally. The 
frictional forces exerted by bead 56 on the skirt 48 of knob 44 and bead 
52 on the wall of plunger 8 are sufficient to maintain the knob 44 in any 
desired position against any backward pressure exerted by the container 34 
after the latter has been displaced longitudinally by manual pressure 
exerted on knob 44 in order to actuate valve 36. Alternative means (not 
shown) of maintaining valve 36 in the open position include the provision 
of a plurality of interference ribs on the outer wall of container 34 
and/or the inner wall of plunger 8 which would maintain the container 34 
in its advanced position after being displaced longitudinally by acutation 
of knob 44. 
Neck 58 of cylinder 4 is provided with threaded needle valve 60 (shown in 
the closed position) which can be rotated axially to open and to provide 
any desired rate of flow of liquid from chamber 62 for dispensing via the 
tip 66 of attached cannula 64. The inner contours of neck 58 correspond 
substantially to the outer contours of throat 16 of piston 6 so that, when 
piston 6 and attached plunger 8 are fully inserted into cylinder 4, the 
piston 6 is received in close fitting relationship with the inner end of 
cylinder 4 and any fluid or air previously present in cylinder 4 is 
substantially completely displaced therefrom. 
The mode of operation of a device according to the invention will now be 
described with reference to FIGS. 1-4. In order to introduce fluid into 
chamber 62 the needle valve 60 is opened, piston 6 and attached plunger 8 
are thrust fully into cylinder 4 to displace any air therefrom through 
valve 60 and attached cannula 64. This position is shown in perspective 
drawing in FIG. 4. Tip 66 of cannula 64 is then immersed in fluid in an 
appropriate container and a predetermined amount of fluid is drawn into 
chamber 62 by withdrawing plunger 8 and attached piston 6 an appropriate 
distance longitudinally in cylinder 4, followed by closure of needle valve 
60 advantageously prior to removal of tip 66 from the fluid in the 
container. The position of piston 6 and attached plunger 8 after drawing 
fluid into chamber 62 in the above manner is shown in FIGS. 1 and 3. 
As shown in FIGS. 3 and 4 the skirted flange 30 is preferably provided with 
raised ribs or like grip-facilitating means to aid in manual manipulation 
of plunger 8. Similar grip-facilitating means are preferably also provided 
on collar 26 of cylinder 4 and on skirt 68 of the needle valve 60. 
The amount of fluid drawn into chamber 62 is indicated by scale 70 disposed 
on the outer wall of plunger 8. Alternatively, when cylinder 4 is 
fabricated from transparent material which permits the level of fluid in 
chamber 62 to be observed directly, a corresponding scale can be disposed 
on the outer wall of cylinder 4 itself. 
Where the device 2 is employed to mix two or more different fluids, the 
required amount of each fluid is drawn into the chamber 62 sequentially in 
the above manner and the resulting mixture of fluids is thoroughly blended 
by appropriate shaking of the device 2. 
The intake of fluid(s) in the above manner leaves the device 2 in the 
position shown in cross-section in FIG. 1. In order thereafter to convert 
the device 2 to the liquid dispensing mode, the plunger 8 is first 
disconnected from piston 6 by appropriate manual rotation of skirted 
flange 30 to disengage threads 10 and 12. Plunger 8 is then locked firmly 
in sealing engagement with rim 24 on the upper end of cylinder 4 by 
screwing threaded collar 26 down tightly so as to compress O-ring 28 
between the underside of collar 26 and the upper inwardly sloping surface 
of rim 24. With plunger 8 locked rigidly in place in this manner, 
propellant gas container 34 is moved longitudinally in plunger 8 by manual 
pressure exerted on the outer end of actuating knob 44. Valve stem 36 is 
thereby caused to move into container 34 thereby relasing pressurized 
propellant gas from said container via orifice 42 and passageway 12. 
Detached piston 6 is thereby biased away from plunger 8, as shown in FIG. 
2, and pressurizes the fluid in chamber 62. The fluid is then dispensed 
from the chamber 62 at any desired flow rate by opening and adjusting 
needle valve 60. 
As set forth previously, the frictional forces holding actuating knob 44 in 
position in plunger 8 are sufficient to retain the knob 44 in the 
container actuated position so that valve stem 36 remains biased in the 
open position. Hence it is unnecessary to maintain constant manual 
pressure on knob 44 in order to maintain flow of liquid from the chamber 
62. Thus, once dispensing of liquid has commenced, the dispensing 
operation can be continued until all fluid has been expelled from chamber 
62. Alternatively, if desired, the flow of liquid can be interrupted at 
any time by closure of needle valve 60 and, optionally, by release of 
actuating pressure of knob 44 on container 34. 
The device 2 is of such size that it can be held conveniently in one hand 
and, once activated for dispensing in the manner described above, used to 
deliver fluid to a locus to be treated leaving the other hand of the 
operator free to carry out whatever additional procedures are necessary 
concurrently with the liquid dispensing procedure. 
The various components which make up the device 2 are preferably fabricated 
by injection molding or like technique from resilient structural plastic 
materials such as polypropylene, polycarbonates, polyamides and the like. 
Because of the resilient nature of such plastics, the piston 6, plunger 8 
and actuating knob 44 can be assembled by snapping the former into the 
cylinder 4 and the latter two into each other in the appropriate order. 
The cannula 64 is preferably integrally formed on the needle valve 60 as 
shown in FIGS. 1-4 but can be formed separately and attached to the exit 
port of needle valve 60 by any appropriate means known in the art. 
While the device of the invention can be employed for dispensing of any 
type of fluid using a hand held instrument it is particularly useful in 
periodontal applications which normally require the mixing of two or more 
fluids immediately prior to applying the fluid so formulated to gum 
tissue. Illustrative of such formulations are those obtained by mixing 
solutions of providone iodide and hydrogen peroxide in measured 
proportions. 
After use, the device of the invention can be disposed of in any suitable 
manner. Alternatively, the device can be prepared for re-use by replacing 
the container of propellant gas with a newly charged container and 
subjecting the other components of the device to cleaning and 
sterilization (if necessary). 
It is to be understood that, although specific embodiments of the invention 
have been described herein in detail, such description is for purposes of 
illustration only and is not intended to be limiting. Modifications which 
can be made thereto without departing from the scope of the invention will 
be obvious to those skilled in the art.