Syringe needle abstract
According to this invention, there is provided a filter device
adapted to be used with a syringe and a needle wherein longitudinally
positioned hollow filter fibres and a flow blocking material are
arranged within the tubular body for directing flow through the
material of the hollow fibres. The device according to the invention
can be embodied either as a single filter element or as a combination
syringe, filter and needle.
Syringe needle claims
I claim What is claimed is:
1. A filtering device, adapted to be used with a syringe and a
needle, for filtering fluids drawn in or ejected from said syringe,
said filtering device comprising:
(a) An elongate tubular body having a first mounting means on one
end thereof adapted to be sealingly connected to the needle mounting
on said syringe and a second mounting means on the opposite end
thereof adapted to be sealingly connected to the cooperative syringe
mounting means on said needle;
(b) Elongate microporous hollow filter fibres arranged longitudinally
within said tubular body, said fibres being closed at one end thereof
and open at the opposite end thereof; and,
(c) Flow blocking material arranged around said fibres for blocking
flow through said tubular body other than through the material of
said hollow fibres, said flow blocking material being provided at
a position in said elongate tubular body to provide with said elongate
microporous hollow filter fibres a reservoir of fluid around said
hollow filter fibres to promote transverse flow of said fluid through
the material of said hollow filter fibers,
(d) Said first mounting means being adapted to be connected to
a male needle mounting means of conical configuration of a syringe
and said second mounting means being adapted to be sealingly connected
to a female mounting means of conical configuration of a needle,
said first and second mounting means being conical in configuration
and adapted to mate with corresponding conical portions of said
needle mounting means and said needle, the conical angle of said
concial mounting being about 1' to 2', said flow blocking material
being located in said tubular body adjacent the end of said tubular
body having said second mounting means, the open end of said elongate
microporous hollow fibres being adjacent the end of said tubular
body having said second mounting means, the ratio of length to the
outside diameter of said elongate tubular body being in the range
of about 5 to 20 the porosity rating of said fibres being in the
range of about 0.05 to about 1 micron and the packing density of
said fibres being less than about 60%, the porosity of said fibres
being greater than about 50%, the effective filtering area of said
fibres being about 1 cm to about 10 cm the total length of said
filtering device beinb about 0.5 inches to about 4 inches, the outside
diameter of said elongate tubular body being about 0.10 inches to
about 0.30 inches and, the inside diameter of said elongate tubular
body being about 0.05 inch to about 0.20 inches.
2. A combination syringe, filter and needle comprising:
(1) a syringe having a mounting means thereon;
(2) a needle having a mounting means thereon;
(3) a filter for filtering fluids drawn in or ejected from said
syringe, said filter comprising:
(a) an elongate tubular body having a first mounting means on one
end thereof adapted to be sealingly connected to the needle mounting
on said syringe and a second mounting means onthe opposite end thereof
adapted to be sealingly connected to the cooperative syringe mounting
means on said needle;
(b) elongate microporous hollow filter fibres arranged longitudinally
within said tubular body, said fibres being closed at one end thereof
and open at the opposite end thereof; and,
(c) flow blocking material arranged around said fibres for blocking
flow through said tubular body other than through the material of
said hollow fibres, said flow blocking material being provided at
a position in said elongate tubular body to provide with said elongate
microporous hollow filter fibres a reservoir of fluid around said
hollow filter fibres to promote transverse flow of said fluid through
the material of said hollow filter fibers,
(d) said first mounting means being adapted to be connected to
a male needle mounting means of conical configuration of a syringe
and said second mounting means being adapted to be sealingly connected
to a female mounting means of conical configuration of a needle,
said first and second mounting means being conical in configuration
and adapted to mate with corresponding conical portions of said
needle mounting means and said needle, the conical angle of said
conical mounting being about 1' to 2', said flow blocking material
being located in said tubular body adjacent the end of said tubular
body having said second mounting means, the open end of said elongate
microporous hollow fibres being adjacent the end of said tubular
body having said second mounting means, the ration of length to
the outside diameter of said elongate tubular body being in the
range of about 5 to 20 the porosity rating of said fibres being
in the range of about 0.05 to about 1 micron and the packing density
of said fibres being less than about 60%, the porosity of said fibres
being greater than about 50%, the effective filtering area of said
fibres being about 1 cm to about 10 cm the total length of said
filtering device being about 0.5 inches to about 4 inches, the outside
diameter of said elongate tubular body being about 0.10 inches to
about 0.30 inches and, the inside diameter of aid elognate tubular
body being about 0.05 inch to about 0.20 inches.
Syringe needle description
BACKGROUND OF THE INVENTION
This invention relates generally to a filtering device adapted
to be used with a syringe and a needle; and, in another embodiment
of the invention, to a combination syringe, needle and filter.
The current state of the art of syringe filters is believed to
involve the use of a round flat sheet microporous membrane that
is sealed between two plastic halves as an intermediate filter typically
for use between a syringe and needle. If air is introduced to the
syringe side of one of these filters and pressure is applied, the
air is compressed over the entire surface area of the membrane thus
substantially blocking or minimizing the flow of fluid. It will
be appreciated, that if liquid is introduced to the syringe side
of the flat filter (which is horizontal to the vertical axis of
the syringe and needle), the liquid will only cover the entire surface
of the membrane, in most cases, if the syringe and needle are in
a vertical position. If the syringe and needle are in a horizontal
position, or angled, the liquid may only cover part of the surface
of the membrane thus causing air blockage. Moreover, increased filtering
capacity of such filters can only be attained by increasing the
diameter resulting in filters having dimensions that sometimes exceed
the diameters of the syringe barrels to which they are attached
and result in awkward handling.
In recent years, attempts to devise various syringe filters have
resulted in that shown in U.S. Pat. No. 4316462 which discloses
an adapter which extends between the needle that is already in place
on the syringe and a second needle. A flat membrane filter is used
in this adapter.
According to this invention, there is provided a filtering device
adapted to be used with a syringe and a needle wherein longitudinally
positioned hollow filter fibres and a flow blocking material are
arranged within the tubular body for directing flow through the
material of the hollow fibres. The device according to the invention
can be embodied either as a single filter element or as a combination
syringe, filter and needle.
The foregoing arrangement produces the advantage that, even though
the syringe and needle are tipped from vertical during use, the
fluid will pass through the filter fibers tangentially to the longitudinal
axis of the filter, thus eliminating air blockage. If air is present,
any air blockage that will occur will be minimal compared to the
flat membrane filters.
SUMMARY OF THE INVENTION
According to this invention, there has been provided a filtering
device adapted to be used with a syringe and needle including an
elongate tubular body having a first mounting means on the end thereof
adapted to be sealingly connected to the needle mounting on said
syringe and a second mounting means on the opposite end thereof
adapted to be sealingly connected to the cooperative syringe mounting
means on said needle. Elongate microporous hollow filter fibres
are arranged within said tubular body with said fibres being closed
at one end thereof and open at the opposite thereof. A flow blocking
material is arranged around said fibres blocking flow through said
tubular body other than through the material of the hollow fibres.
In accordance with another aspect of the invention, there is provided
a combination syringe, needle and filter utilizing a filter of the
foregoing type between the syringe and the needle.
It was an object of this invention to provide a filter for a syringe
and needle whereby the fluid drawn into the syringe through the
needle or ejected from the syringe through the needle was filtered
by a filter means intermediate the syringe and needle.
A further object of this invention was to provide a filter of the
foregoing type which would eliminate or minimize air blockage.
A still further object of this invention was to provide a filter
for use with a syringe and needle that would be easy to manufacturer
and convenient to use.
These and other objects of the invention will be evident from the
following more detailed description of the invention.
DESCRIPTION OF THE DRAWINGS
The invention will be more fully understood and described with
reference to the drawings wherein:
FIG. 1 is a view in cross-section of a syringe, needle and filter
according to the invention;
FIG. 2 is a cross-sectional view of the filter according to the
invention;
FIG. 3 is a view in cross-section taken on lines 3--3 of FIG. 2;
FIG. 4 is a view similar to FIG. 2 showing an alternate embodiment
of the invention; and,
FIG. 5 is a view in cross-section taken on lines 5--5 of FIG. 4.
DETAILED DESCRIPTION OF THE INVENTION
There is shown in FIG. 1 an arrangement according to the invention
including a syringe 10 a filter 11 and a needle 12. The syringe
has a barrel member 13 and a plunger element 14. The syringe includes
a male needle mounting means 15 having a conical surface 16 that
is normally adapted to mate with a mounting means on a needle such
as needle 12. Conical surface 16 terminates in opening 17. Filter
11 includes an elongate tubular body 18 having a first mounting
means 19 of outwardly tapered concial configuration adapted to mate
with conical surface 16 of syringe 10 in a fluid sealing manner.
At the opposite end of elongate tubular body 18 there is a second
mounting means 20 of inwardly tapered conical configuration adapted
to mate with corresponding mounting means of a needle such as needle
12.
Needle 12 includes an outwardly tapered female mounting means 21
of conical configuration and cannula 22.
Mounted inside elongate tubular body 18 are elongate microporous
hollow filter fibres 23. As best shown in FIG. 2 hollow fibres
23 have an open end 24 and a closed end 25. While a single fibre
can be used having an open end and a sealed closed end, the arrangement
shown in FIG. 2 wherein a fibre is looped back upon itself to form
two open ends 24 with the loop providing closed ends 25 is preferred.
Flow blocking material 26 is arranged to position hollow filtering
fibres 23 in elongate tubular body 18 such that flow through tubular
body 18 other than through the material of hollow filtering fibres
23 is blocked. It is preferred to have the blocking material 26
in this position to provide a reservoir of fluid upstream of said
material in said elongate tubular body 18 to promote transverse
flow of said fluid material through the material of hollow filter
fibres 23.
In a preferred form of the invention, the concial surfaces of elements
16 19 20 and 21 all have a conical angle of from about 1' to about
2'.
The elongate tubular body 18 of filter 11 in its referred form,
should not exceed the diameter of a barrel member 13 of syringe
10.
In a preferred form, the total length of filter unit 11 will be
about 0.5 inches to about 4 inches with a preferred outside diameter
in the range of about 0.10 inches to about 0.30 inches with an inside
diameter approximating about 0.05 inches to about 0.20 inches. The
ratio of length to the outside diameter of filter will be in the
range of about 2 to about 20.
The microporous hollow fibres 23 can be of any length, preferably
up to and including the length of tubular body 18 less the depth
of protrustion of the male needle mounting means 15 which otherwise
might damage the fibres. The fibres 23 can also be relatively short
in length compared to the length of tubular body 18 provided that
sufficient filtration surface is present for the particular application.
The porosity rating of fibres 23 is in the microporous range of
about 0.05 to about 1 microns. A preferred range is about 0.1 to
about 0.45 microns.
The inside diameter for fibres 23 can be from about 0.008 inches
to about 0.08 inches with a preferred inside diameter being in the
range of about 0.012 inches to about 0.05 inches with a further
preferred diameter being about 0.18 10%. It has been found in accordance
with the invention that larger fibres under the pressures applied
by injection force on the syringe may collapse. Smaller diameter
fibres also increase the packing density. The outside diameter should
be that which will result in a wall thickness of about 0.001 inches
to about 0.005 inches with a preferred wall thickness being about
0.0015 inches to about 0.004 inches.
Flow blocking potting material 26 can be selected from the group
consisting of silicone, polyurethane, epoxy, and cyanoacrylate ester
resins with polyurethane being the currently preferred potting material.
Elongate tubular body 18 in its preferred form is made out of a
rigid plastic material, preferably transparent or transluscent,
such as an acrylic or polycarbonate resin.
The effective filtration area of the microporous hollow fibres
23 in a given filter element 11 is in the range of about 0.25 cm.sup.2
to about 10 cm.sup.2 with a preferred range being about 5.0 cm.sup.2
or less. The effective filtration area is measured on the inside
walls of the fibres.
The porosity of fibres 23 should be greater than about 50% with
a preferred range being about 65% to 85% with the upper range of
porosity being limited at a point where the fibres have no structural
integrity.
Packing density of fibres 23 in tubular body 18 as expressed in
a ratio of cross-sectional areas of fibres to cross-sectional area
of the lumen of tubular body 18 should be less than about 60%. The
number of fibres 23 in tubular body 18 is preferably between 1 and
10 and more preferably between 2 and 8.
In FIG. 4 there is shown an alternate embodiment according to
the invention wherein the elongate tubular body is tapered, in this
case, at an angle of about 1' to about 3' and wherein there are
also included finger grippable projections in the form of an elongate
ribs 27. These ribs extending substantially the length of the tubular
portion 18 of filter unit 11. The existence of ribs 27 make it not
only easier to grip the filter when it is connected with needle
12 and syringe 10 but further make it easier to install on the
syringe and to facilitate removal and connection with needle 12.
An added advantage of the elongate filter 18 of the invention is
that the filter itself will fit into ampoules for the withdrawal
of liquids therefrom. The filter, therefore, has the advantage of
filtering either in asperation or injection of fluids.
As best shown in FIG. 5 grips 27 can be spaced equal distance
around tubular body 18 and it is preferred to have such ribs projecting
from said tubular body at a distance in the range of from 0.008
to 0.015 inches. The elongate ribs 27 are themselves tapered and
it is preferred that the angle of taper be from about 1.0 to about
1.5 degrees. The taper of the tube 18 and the ribs 27 facilitate
manufacture of the filter by the injection molding process whereby
the parting line can be at the face 28 of a standard luer fitting
29. It is also preferred, to have the interior of tube 18 tapered
at an angle substantially the same as that of the exterior to provide
for easy removal from mold parts in the injection molding process.
The invention may be embodied in other specific forms without departing
from the spirit or essential characteristics thereof. The present
embodiments are therefore to be considered in all respects as illustrative
and not restrictive, the scope of the invention being indicated
by the appended claims rather than by the foregoing description;
and all changes which come within the meaning and range of equivalency
of the claims are therefore intended to be embraced therein. |