U.S. patent number 3,831,816 [Application Number 05/374,983] was granted by the patent office on 1974-08-27 for chemical syringe.
Invention is credited to Richard S. Pauliukonis.
United States Patent |
3,831,816 |
Pauliukonis |
August 27, 1974 |
CHEMICAL SYRINGE
Abstract
A device with improved accuracy, repeatability and reliability
in collecting a first fluid such as samples of blood in a syringe
or other fluids of various volumes in a dispenser, including
volumes of a few lambdas and up to a few ounces, and mixing first
fluid volume with a second fluid volume ideally measured in
quantities of multiples of 1 to 1,000 times the first fluid volume,
which operates by means of a built-in positive displacement with
cut-off by a reciprocating plunger containing a telescoping spring
loaded piston rod assembly and entering a barrel filled with second
fluid with provision of collecting a first fluid by suction into a
receiver such as pipette through an elongated passage at the barrel
end which can also serve as receiver for the first fluid,
simultaneously the plunger moves up from the first discharge
position to the second filling position. incorporating a means of
filling the barrel only when the plunger is at the barrel top and
the barrel is under partial vacuum until the plunger seal
disengages the barrel rim to enter larger diameter end cap portion
connected to a second fluid supply permitting an instantenous
barrel filling with second fluid and means for control of
volumetric displacement by cut-off when plunger starts to descend
closing the barrel rim by the plunger seal and subsequently during
downstroke pressurizing second fluid trapped in the barrel to
simultaneously disengage the piston rod end from the elongated
passage at the barrel end discharging the fluids mixed from the
barrel during descend of the plunger and also washing the discharge
passage with surplus of second fluid exhausting from the barrel
after the first fluid was discharged under pressure of the second
fluid therefrom by piston rod reentering the elongated passage by
the force of a spring when the pressure of the second fluid dropped
at the end of the plunger downstroke rendering the device ready to
repeat the cycle of simultaneous filling of two different fluids on
upward motion of the plunger and their mixing during the discharge
on downward plunger motion, such motion controlled externally by
mechanical or electromechanical means such device including
volumetric adjustment of second fluid discharge therefrom.
Inventors: |
Pauliukonis; Richard S.
(Cleveland, OH) |
Family
ID: |
23479020 |
Appl.
No.: |
05/374,983 |
Filed: |
June 29, 1973 |
Current U.S.
Class: |
222/135; 222/386;
422/927 |
Current CPC
Class: |
B01L
3/0231 (20130101) |
Current International
Class: |
B01L
3/02 (20060101); B67d 005/56 () |
Field of
Search: |
;222/386,420,422,309,135
;128/218M |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Tollberg; Stanley H.
Claims
What is claimed is:
1. A device for mixing precisely two different liquids in various
quantities at fixed proportions comprising:
a housing means with fluid cavity and fluid supply and discharge
means therein, plunger means inside said housing means including an
intergral telescoping piston rod assembly and adaptable to be moved
inside said housing means from first discharge position to second
filling position by suction when plunger is urged to change such
position by external device operating means, means for collecting
and storing first liquid amount at fluid discharge means
simultaneously when generating partial vacuum inside said cavity of
said housing means for instantaneous filling of said cavity with
second liquid volume when said plunger is in said filling position,
means of maintaining two different liquids in said device after
filling unmixed, means for discharging said fluids from said device
via said discharge means during the position change of said plunger
from said second filling position to said first discharge position
whereby said second liquid volume from said cavity is mixed
thoroughly with said first liquid volume within said discharge
means, automatic control means of said discharge during said
position change from said second filling position to said first
discharge position, said control means including said telescoping
piston rod assembly whereby said piston is urged by the pressure of
discharging second volume fluid to disengage said discharge means
allowing said mixing of said second liquid volume with said first
liquid upon such discharge caused by said plunger position change
when urged by said external operating means, and means of adjusting
volumetric quantities of liquids collected during said second
filling cycle and mixed during said first discharging cycle,
including means of precise liquid displacement from said cavity by
cut-off controlled by said plunger inside said fluid cavity of said
housing means, said cut-off with exact liquid volume trapped and
pressurized in said cavity controlled during said position change
from said second filling position to said first discharge position
when said plunger is urged to change the direction of movement in
said housing caused by external operating means of said device
mechanically forcing said plunger to descend inside said cavity
displacing said second liquid volume therefrom, automatically
opening liquid discharge passage controlled by said telescoping
piston rod assembly urged to simultaneously ascend by said fluid
pressure during said discharge cycle uncovering said discharge
opening means automatically for said discharge of liquids mixed
therefrom.
2. A chemical syringe for mixing two liquids in precise quantities
comprising: a housing means including an elongated barrel with
cavity therein and one end open and adaptable to be closed by an
end cap and the other end provided with small fluid discharge
opening passing centrally therethrough and adaptable to be
connected to a pipette, an end cap having a central passage
therethrough and a mouth for closing said open barrel end, a
plunger means in said housing means including internally
telescoping piston rod assembly therein, said plunger slidably
received in said central passage of said end cap and adaptable to
enter snugly said open barrel end axially for sliding therein from
first fluid discharge position by pressure to the second fluid
filling position by suction when plunger is moved to shuttle by
external means, fluid supply port in said end cap for communication
with said barrel cavity when said plunger is moved to ascend and to
disengage said barrel open end at the end of said second fluid
filling position allowing an instantenous barrel filling with first
fluid of large volume, means for sample collection in said pipette
of small liquid volume of second fluid when said plunger is moved
from said first discharge position to said second filling position
by suction created by piston rod end of said telescoping piston
rod-assembly inside said fluid discharge opening of said barrel,
means for holding said first and said second fluids in their
respective compartments separated for as long as said plunger is in
said second filling position, means for mixing said fluids upon
fluid discharge via said small fluid discharge opening in said
barrel when said plunger is moved to descend pressurizing said
first fluid inside said barrel when said plunger end reenters said
barrel open end during the discharge cycle and continues downward,
means for an automatic opening of said discharge passage by
disengaging said piston rod end therefrom when first fluid pressure
is large enough to overcome biasing force means holding said piston
rod end in said discharge opening including means for discharge
flow control by said telescoping piston rod assembly in response to
said pressurization of said first fluid inside said barrel and for
mixing said first with said second fluids during said fluid
discharge accompanied by said piston rod ascent from said fluid
discharge opening, including means for washing pipette at the end
of discharge cycle by said first fluid during the automatic reentry
of said piston rod end into said discharge opening when said
plunger descent is stopped discontinuing said pressurization of
said first fluid with accompanied action over said telescoping
piston and said biasing force exceeding said pressure force over
said piston forcing return of said telescoping piston-rod assembly
to the original position with piston rod fully extended inside said
discharge opening and ready to begin new suction and filling cycle
of both the pipette with sample fluid from a test tube and the
barrel with large fluid volume from a reservoir.
3. A chemical syringe as in claim 2 wherein when said plunger is in
said first discharging position, said first fluid is subjected to
pressurization inside said barrel cavity exerting pressure force on
said telescoping piston of said piston rod assembly urging said
piston to move into the opposite direction thereby disengaging
piston rod end from said discharge opening during said discharge
cycle whereby said plunger is moved to descend inside said barrel
by external means, said external means including a mechanical
operator attached to said plunger operating end provided with a
blind plug.
4. A chemical syringe as in claim 3 including a spring providing a
biasing force to said telescoping piston-rod assembly inside said
plunger when located therein abutting said piston at one spring end
and said blind plug at the other spring end including an air vent
hole in said plug, said spring exerting sufficient force over said
piston to retain said piston rod assembly tight against a plunger
shoulder with rod extended and rod end engaged inside said
discharge opening when said plunger is in said second filling
position and when said plunger is in said first discharge position
pressurizing said first fluid inside said barrel, said piston rod
assembly is forced to telescopingly slide into plunger opening
against said spring thereby compressing it further, said
telescoping sliding motion controlled automatically by said
pressure of said first fluid on said piston surface exposed thereto
in conjunction with fluid discharge speed as regulated by the
position change of said plunger during said discharge cycle, said
spring tending to return to the original less preloaded position
automatically returning said piston rod end into engagement with
said discharge opening of said barrel when said plunger is at the
end of said first discharge cycle and said first fluid pressure has
dropped to that below of said biasing force of said spring.
5. A chemical syringe as in claim 2 wherein said barrel is
adaptable to be adjusted within said engagement with said end cap
providing volumetric displacement control of said first fluid
discharge from said barrel cavity when said plunger stroke is
fixed.
6. A chemical syringe as in claim 2 wherein said biasing force
means are separated from said first fluid inside said barrel cavity
by seals.
7. A chemical syringe as in claim 2 wherein said fluid separation
and holding first fluid inside barrel cavity and second fluid
inside said pipette during said second filling cycle including
seals in said plunger end and in said rod end, said rod end seal
providing means for holding said first and said second fluids in
their respective compartments separated for as long as said plunger
is in said second filling position.
8. A chemical syringe as in claim 2 wherein said mixing of said
first and said second fluid is accomplished during said first
plunger discharge position when said plunger descends and said
piston rod end ascends from said discharge opening allowing exhaust
of said first fluid into said pipette before exiting into the
receiver together with said second fluid forced by said first fluid
pressure therefrom mixed, including washing said pipette by said
first fluid flow therethrough.
9. A chemical syringe as in claim 2 including means for controlling
sample collection inside pipette, said means including recess
inside discharge opening facing pipette to facilitate free sliding
fit of the piston rod end therein when plunger is at the end of
said discharging cycle and the piston rod assembly is urged to
reenter said discharge opening by said biasing force wherein when
the plunger is in filling cycle, said plunger end seal enters said
opening end adjacent said chamber cavity for sealing and pipette
suction means of closer fit provided therein.
10. A device as in claim 1 for mixing two different liquids wherein
the first fluid is collected by suction inside said discharge
passage means and the second fluid is collected via fluid supply
port entering large diameter end cap portion inside said barrel
cavity simultaneously when said plunger is urged to move upward,
and mixing said first with said second fluids during said discharge
stroke when said plunger is urged to move downward, said plunger
motion controlled externally by mechanical means, said mechanical
means urging said position change of said plunger in a
reciprocating fashion continuously in a device dispensing mixed
fluids automatically.
11. A device as in claim 1 wherein said collecting and storing of
said first liquid at fluid discharge means including an attachment
containing directional check valves.
12. A device as in claim 11 including sealing means for improved
suction of collecting said first fluid and for separating said
first from said second fluids collected therein.
Description
This invention relates to mixing equipment, and more specifically
to the equipment used with various chemicals requiring mixing of
two liquids of different nature in precise quantities repeatedly
for subsequent service or for analytical studies.
Syringes representing present state of the art in this type of
equipment are incapable of providing accurate, repeatable and
reproduceable operation because they either employ a unidirectional
cycle for simultaneous suction of sample and of reagent in separate
individual compartments interlocked by valves each complex in its
design and subject to volumetric efficiencies which as a whole can
not physically provide unit operation of dependable performance, or
they are made to perform separately collecting sample first then
mixing such sample with reagent taken separately in a receiver with
notoriously inaccurate results.
A syringe that would alleviate above mentioned shortcomings has
been invented. The object of the present invention is therefore to
provide a syringe design that advances superior performance
characteristics and permits a solution to an age old problem of
accurate measurements and mixing of two different liquids precisely
in a repeated cycle.
A further object is to provide less complex design entailing such
control capability by elimination of components and of steps in
sample collection and in mixing such sample with appropriate
reagent simultaneously in a syringe which is simple to make and to
operate.
Another object of this invention is to provide a syringe which
incorporates washing capabilities of sample cavities by reagent
outflow at the cycle end to intensity cleanness and to prevent
sample contamination in automatic sequential system operation
involving multiple sample collection and accelerated analytical
testing within novel techniques.
Devices of this type which require fewer components for syringe
construction and operation, and improve ultimate performance of the
system are obviously desirable.
These and other objects and advantages of the invention will become
more fully apparent from the following description of the
embodiment of the invention, taken together with the accompanying
drawings:
IN THE DRAWINGS
FIG. 1 identifies a cross-section of the syringe with components
positioned at the end of the suction cycle with plunger
extended.
FIG. 2 shows the same syringe with components positioned during the
discharge of syringe prior to the cycle completion with plunger
retracted and piston rod withdrawn from discharge passage opening
leading to the pipette for fluid exhaust.
FIG. 3 identifies the same syringe at the end of the cycle with
plunger retracted and piston rod positioned inside fluid passage
opening after fluid discharge, ready to start suction inside
pipette by the piston rod and inside syringe barrel by the plunger
during the next cycle.
Shown in FIG. 1 is a syringe housing 10 with a barrel 11 of
elongated configuration with one open end 12 counterbored by a
cavity 13 which continues inwardly to terminate wth a shoulder 14
having central smaller diameter fluid passage opening 15 exiting at
the other end 16 which in the illustrated case retains a pipette 17
for sample collection from a test tube 18. Open end 12 adaptable to
be closed by an end cap 19 having central opening 20 with O-ring
seal 35 shows a plunger 21 with telescoping piston-rod assembly 44
therein in the extended position, and plunger seal 22 disengaged
from the close fitting engagement inside counterbore 13 while a
piston rod 23 of a piston 24 situated inside coaxial plunger
blind-end opening 25 has piston rod end 26 still engaged inside
opening 15 to block fluid communication therethrough. A side port
27 supplying the reagent into syringe enters the end cap 19 to
communicate with a counterbore 28 coaxially entering end cap open
end 29 which is provided with threads 30 adaptable to close open
end 12 of barrel 11 likewise threaded by mating threads 30-a and,
in the illustrated case, showing a gap 31 between end cap face 32
and barrel shoulder 33 at which threads 30-a end, identifies means
for control of volumetric discharge of reagent from the barrel
cavity 13 during plunger down stroke in operation. With the gap 31
closed and shoulder 33 positioned tight against the end cap face
32, the plunger face 34 would nearly bottom the barrel shoulder 14
when plunger is moved to rectract from the position shown in FIG. 1
to that shown in FIG. 3 displacing nearly all fluid that entered
the cavity 13 of the barrel 11. With the gap 31 present as shown in
FIG. 1, and with fixed plunger stroke length, the volume of reagent
retained in the cavity 13 is proportional to the length of the gap
31 which can be made smaller or larger depending on needs to vary
such volumetric reagent discharge from barrel cavity, with
provisions of simple volume adjustment identified hereby. Means
other than those identified to change volumetric displacement can
easily be incorporated herein without significantly affecting the
operation of this device. The fact remains however that the syringe
includes means for volumetric change should such volume change be
needed, without resorting to more complicated volume adjustments.
The syringe when assembled without the gap 31 and shoulder 33
against face 32 could be used with or without volumetric adjustment
of reagent discharge from the barrel cavity 13, and it would
displace less volume when assembled as illustrated in FIG. 1 with
gap 31 shown as compared with volumetric displacement without gap
31 as shown in FIG. 3, when plunger stroke length is fixed.
Returning back to FIG. 1 we see spring 36 abutting blind plug 37
with air vent hole 38 of the plunger operating end 39 at one spring
end and piston 24 provided with appropriate seal 40 at the other
spring end to maintain piston against shoulder 25-a of opening 25
and rod end 26 inside opening 15 for communication of port 27 via
annular space 41 formed between counterbore 28 of end cap 19 and
the plunger 21 end of which is disengaged from cavity 12 permitting
an instantaneous feeding of the barrel with reagent every time
plunger is pulled out of the seat at the end of suction stroke. The
discharge of the reagent from the barrel cavity can not take place
until the plunger becomes depressed to change the direction and to
reengage the open end 12 of the barrel cavity 13 upon retraction of
plunger during discharge stroke cutting off an exact amount of
fluid at the rim of barrel cavity during the initiation of such
discharge cycle and compressing this fluid volume during down
stroke sufficiently to exert ample force over piston side 42
provided with piston rod 23 and facing reagent under pressure to
move upward during plunger down-stroke simultaneously opening fluid
exhaust passage 15 rather automatically as the reagent is normally
incompressible and the downstroke of plunger is expected to exert
substantial force for this automatic fluid exhaust control from
within providing novel means for controlled and repeatable
performance of syringe with precision unattainable henceforth. This
is clearly illustrated in FIG. 2 which shows the same syringe with
components positioned to permit reagent discharge prior to the
cycle completion via discharge opening 15 leading to pipette 17 for
exhaust into a receiver 43 for further analysis by other
instruments in an automatic system, designated to perform
analytical studies of blood or other two component chemicals. In
particular this is evident from the fact that the spring 36 in FIG.
2 is compressed due to the piston 24 upward motion caused by
reagent pressure inside cavity 13 entering plunger opening 25 for
acting over piston face 42 with resultant axial motion against
spring 36 for as long as the plunger descends during the downstroke
cycle maintaining the piston 24 under pressure and piston rod end
26 disengaged from opening 15 to ascertain fluid discharge via
pipette 17. The reagent supply port 27 in FIG. 2 identifies direct
communication with annulus 41 formed between plunger 21 and end cap
19 counterbore 28 but separated from entering barrel cavity 13 by
plunger seal 22 at one end and from exiting into the atmosphere via
openig 20 at the other end by end cap seal 35 until the position of
plunger changes to that shown in FIG. 1 at which the barrel cavity
becomes instantaneously filled during filling stroke described when
discussing FIG. 1. To note is the fact that the spring 36 when
compressed as shown in FIG. 2 exerts a biasing force constantly
acting against piston 24, seeking the opportunity to return the
piston 24 with rod 23 to the original position with compression
spring 36 extended as that shown in FIG. 1 or FIG. 3. During the
spring compression from that shown in FIG. 1 to that shown in FIG.
2 the hole 38 permits air venting rendering unobstructed piston 24
upward motion and spring 36 compression as that shown in FIG. 2.
Gap 31 shown in FIG. 2 identifies volumetric adjustment in
existence during this cycle phase.
FIG. 3 identifies the same syringe at the end of the plunger
retraction cycle wherein the plunger 21 has bottomed at the barrel
shoulder 14 or nearly touches it when the plunger downstroke
externally controlled by mechanical means is at maximum and the
pressure of the reagent has dropped below the spring biasing force
permitting spring 36 to relax by extending and by pushing
simultaneously the piston 24 with rod 23 attached permanently
thereto to reenter discharge opening 15 in final steps of the
return cycle and to expel all residue of reagent that may have
accumulated therein upon discharge of the syringe during the
interim period described when discussing conditions identified in
FIG. 2. Because the design of the piston rod 23 considered a close
sliding fit entailing sealing characteristics when inside opening
15, in particular by purposely making rod end 26 snuggly fitting
inside the opening 15, the separation and the discharge as well as
suction by piston rod end within the opening 15 is thereby insured.
Because the diameteral difference between rod end 26 and the rod 23
is very small the drawings identify only the length of rod end but
not the diameteral differences. Also not shown is a diametral
recess of the fluid discharge passage identified by 15 which in
some special cases may be made slightly larger than the diameter of
opening 15, in particular in cases requiring suction level control
of pipette or needle. In practice therefore the piston rod end 26
in most applications may slide inside fluid discharge opening 15
snugly with rod of close fitting diameter irrespective of the rod
end position therein resulting in full suction and sealing along
the whole discharge passage length, and in some applications it may
be made to enter discharge opening 15 having snug diameteral fit at
the beginning and partway inwardly and thereafter proceed further
inwardly relatively free inside a recess of the discharge passage
length.
For cases requiring large opening 15 for large capacity
instruments, the rod end 26 may even employ an O-ring (not shown)
to facilitate positive suction of large flows through the pipette.
However, because in majority of cases such pipette collects rather
small blood samples varying between 10 and 50 lambdas of volume per
cycle and utilizes small diameters limited sometimes to capillary
sizes, the piston rod end 26 may be produced with sealing
capabilities even without the use of O-ring seals if made from
plastics, glass or other suitable materials for rod construction
normally used when building anticorrosive laboratory equipment.
Obviously, this device would function without pipette as well by
storing fluid in opening 15. The pipette 17 in such cases can be
replaced by an attachment (not shown) containing appropriate
directional check valves, and the syringe may become a dispenser
device for mixing two different liquids in one container,
mechanically operated by external means.
The invention is not restricted to the slavish imitation of each
and every one of the details described above which have been set
forth merely by way of example with the intent of most clearly
setting forth the teachings of the invention. Obviously, devices
may be provided which change, eliminate or add certain structural
or procedural details without departing from the invention.
* * * * *