Syringe pump abstract
A syringe pump including a syringe including a plunger that slides
in a body which has a discharge port, a driving mechanism coupled
to the syringe, including a cylinder in which a piston mounted on
a shaft slides, and a biasing device operative to apply an urging
force on the piston to drive the piston distally in the cylinder,
and a safety catch that initially prevents the biasing device from
moving the piston, the safety catch being removable to permit the
biasing device to move the piston.
Syringe pump claims
What is claimed is:
1. A syringe pump comprising: a syringe comprising a plunger that
slides in a body which has a discharge port; a driving mechanism
coupled to said syringe, comprising a cylinder in which a piston
mounted on a shaft slides, and a biasing device operative to apply
an urging force on said piston to drive said piston distally in
said cylinder; and a safety catch that initially prevents said biasing
device from moving said piston, said safety catch being removable
to permit said biasing device to move said piston.
2. The syringe pump according to claim 1 wherein said cylinder
is at least partially filled with a hydraulic fluid.
3. The syringe pump according to claim 2 wherein said piston is
formed with a vent hole that passes through the thickness of said
piston and is in fluid communication with a port in said shaft,
wherein said vent hole and said port permit flow of said hydraulic
fluid from a distal portion of said cylinder in front of said piston
to a proximal portion of said cylinder behind said piston.
4. The syringe pump according to claim 2 wherein a biasing force
of said biasing device on said piston and a hydraulic damping of
said hydraulic fluid provide a close-to-linear pumping force.
5. The syringe pump according to claim 1 wherein said driving
mechanism is coupled to a head of said plunger with a clasp.
6. The syringe pump according to claim 1 wherein said biasing
device comprises a coil spring disposed on a portion of said shaft.
7. The syringe pump according to claim 1 wherein said syringe
contains sperm therein.
8. The syringe pump according to claim 1 wherein said syringe
and said driving mechanism are housed in a casing.
9. The syringe pump according to claim 8 wherein said casing has
a window through which travel of said driving mechanism is observable.
Syringe pump description
FIELD OF THE INVENTION
[0001] The present invention relates generally to syringe pumps,
and particularly to a disposable syringe pump for sperm delivery,
such as in slow-release insemination.
BACKGROUND OF THE INVENTION
[0002] Microfluidic pumping devices are used in numerous applications,
such as administration of medicine and biological and pharmaceutical
research. Such pumping devices include mechanical pumps, such as
syringe-type pumps and micromechanical pumps, and non-mechanical
pumps, such as electrohydrodynamic pumps, electro-osmotic flow pumps,
electrowetting pumps, and thermocapillary pumps.
[0003] There are drawbacks to different pumping devices. For example,
a steady flow rate is difficult to achieve. Moreover, many mechanical
pumps require an electrical power source, as do pumps that operate
based on electrical properties. Many of these pumps are costly and
often have slow response times.
[0004] Conventional syringe pumps are typically employed with either
a syringe or a vial and plunger system for administering a liquid
to a patient. In such conventional systems, a syringe or vial of
the liquid is oriented vertically in a fixed position on the syringe
pump. The bottom of the syringe or vial defines a discharge port
connected to a flexible, hollow tubing which extends to the patient.
The plunger or piston of the apparatus is engaged with the moving
pusher plate or drive member of the syringe pump and is driven downwardly
into the syringe body or vial to force the liquid agent from the
syringe body or vial through the tubing and into the patient.
[0005] An example of such a syringe pump is described in a system
of PCT published patent application WO03008102. The system employs
a microchannel and a gravity driven pump comprising horizontally
oriented fluid supply reservoirs. The pump supplies fluid to the
microchannel at a substantially constant rate. The device may be
used, among other things, for motile sperm sorting.
SUMMARY OF THE INVENTION
[0006] The present invention seeks to provide a novel, disposable
syringe pump for sperm delivery, such as in slow-release insemination,
as described more in detail hereinbelow. The invention may have
other applications and is not limited just to slow-release insemination.
For example, the invention may be used in the laboratory or other
research area for pumping sperm and other fluids.
[0007] There is thus provided in accordance with an embodiment
of the present invention a syringe pump including a syringe including
a plunger that slides in a body which has a discharge port, a driving
mechanism coupled to the syringe, including a cylinder in which
a piston mounted on a shaft slides, and a biasing device operative
to apply an urging force on the piston to drive the piston distally
in the cylinder, and a safety catch that initially prevents the
biasing device from moving the piston, the safety catch being removable
to permit the biasing device to move the piston.
[0008] The syringe pump may include one or more of the following
features. For example, the cylinder may be at least partially filled
with a hydraulic fluid. The piston may be formed with a vent hole
that passes through the thickness of the piston and may be in fluid
communication with a port in the shaft, wherein the vent hole and
the port permit flow of the hydraulic fluid from a distal portion
of the cylinder in front of the piston to a proximal portion of
the cylinder behind the piston. The biasing force of the biasing
device on the piston and hydraulic damping of the hydraulic fluid
may provide a close-to-linear pumping force.
[0009] The driving mechanism may be coupled to a head of the plunger
with a clasp. The biasing device may include a coil spring disposed
on a portion of the shaft. The syringe and the driving mechanism
may be housed in a casing. The casing may have a window through
which travel of the driving mechanism may be observable.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The present invention will be understood and appreciated
more fully from the following detailed description taken in conjunction
with the drawings in which:
[0011] FIG. 1 is a simplified pictorial illustration of a disposable
syringe pump, constructed and operative in accordance with an embodiment
of the present invention;
[0012] FIG. 2 is a simplified cutaway illustration of the syringe
pump of FIG. 1 showing inner components thereof;
[0013] FIG. 3 is a simplified cutaway illustration of a driving
mechanism used in the syringe pump of FIG. 1 constructed and operative
in accordance with an embodiment of the present invention; and
[0014] FIG. 4 is a sectional illustration of a plunger used in
the driving mechanism of FIG. 3 in accordance with an embodiment
of the present invention.
DETAILED DESCRIPTION OF EMBODIMENTS
[0015] Reference is now made to FIG. 1 which illustrates a syringe
pump 10 constructed and operative in accordance with an embodiment
of the present invention.
[0016] The syringe pump 10 may include an outer casing 12 in which
are housed a driving mechanism 14 coupled to a syringe 16. The casing
12 is illustrated as being constructed of two halves joined together
(e.g., by screws, bonding, sonic welding or any other suitable method
of connection), but may be constructed of one part or many parts
as well. The syringe pump 10 may have any size and shape, which
may depend, among other things, on the size and shape of the syringe
16 and the required flow rate. In one non-limiting embodiment of
the invention, syringe pump 10 may be about 5-9 cm long, 5 cm wide
and 3 cm thick.
[0017] The syringe 16 may include a body 18 in which a plunger
20 slides. The body 18 may hold any suitable volume of sperm 22
such as but not limited to, about 0.3-1.5 cc. The syringe 16 may
have a discharge port 24 which may be connected to suitable tubing
and a filter (not shown) for sperm delivery, such as in slow-release
insemination. The syringe 16 and its parts may be made of any medically
safe material, such as but not limited to, polycarbonate, and may
be completely disposable.
[0018] The driving mechanism 14 may be coupled to a head 26 of
plunger 20 such as by means of a clasp 28 or any other suitable
link or connection. The driving mechanism 14 may include a cylinder
30 in which a piston 32 slides. The travel of piston 32 inside cylinder
30 may be bounded by end caps 34. Piston 32 may be mounted on a
shaft 36 which is connected to clasp 28.
[0019] Reference is now made additionally to FIGS. 3 and 4. The
driving mechanism 14 may include a biasing device 38 such as but
not limited to, a coil spring, disposed on a portion of shaft 36
proximal to the piston 32. The biasing device 38 is operative to
apply an urging force on piston 32 to drive piston 32 distally (in
the direction of an arrow 40) in cylinder 30. Initially, a safety
catch 35 may arrest movement of shaft 36 and piston 32. For example,
the safety catch 35 may initially abut against one of the end caps
34 and sit in a notch 33 formed in shaft 36 thereby preventing
biasing device 38 from expanding and moving piston 32.
[0020] Cylinder 30 may be at least partially filled with a hydraulic
fluid 42 such as but not limited to, glycerin. Piston 32 may be
formed with a relatively tiny vent hole 44 (such as but not limited
to, a diameter of 0.1 mm) that passes through the thickness of piston
32 and is in fluid communication with a port 45 in shaft 36. The
combination of vent hole 44 and port 45 permit flow of hydraulic
fluid 42 from a distal portion 46 of cylinder 30 (that is, in front
of piston 32) to a proximal portion 48 of cylinder 30 (that is,
behind piston 32). Accordingly, after removal of safety catch 35
biasing device 38 pushes piston 32 distally in the direction of
arrow 40 and hydraulic fluid 42 is transferred between the distal
portion 46 to the proximal portion 48 of cylinder 30 (located at
the posterior end of the moving plunger) via vent hole 44 and port
45. The combination of the biasing force of biasing device 38 and
the hydraulic damping of the hydraulic fluid 42 may provide a close-to-linear
pumping force.
[0021] Referring again to FIG. 1 it is seen that the casing 12
may be provided with a window 50 through which the travel and forward
progress of driving mechanism 14 may be observed. For example, the
widow 50 may expose a tab 52 formed on shaft 36 which easily allows
observation of the movement of shaft 36.
[0022] The flow or pumping rate of syringe pump 10 may be adjusted
by adjusting or selecting different operating parameters, such as
but not limited to, the spring coefficient of biasing device 38
sizes and shapes of vent hole 44 and port 45 cross sectional area
of cylinder 30 and of body 18 and/or the viscosity of hydraulic
fluid 42 (e.g., in the range of 50-1000 centipoise at 20.degree.
C.).
[0023] It is appreciated that various features of the invention
which are, for clarity, described in the contexts of separate embodiments,
may also be provided in combination in a single embodiment. Conversely,
various features of the invention which are, for brevity, described
in the context of a single embodiment, may also be provided separately
or in any suitable subcombination.
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