U.S. patent number 3,782,548 [Application Number 05/312,817] was granted by the patent office on 1974-01-01 for serum skimmer.
Invention is credited to John G. Bowen.
United States Patent |
3,782,548 |
Bowen |
January 1, 1974 |
SERUM SKIMMER
Abstract
An instrument is provided for skimming serum from the cellular
material, such as the red blood cells, of a blood sample; the cells
having been dispersed, for example, by centrifugal action, to the
bottom of the tubular receptacle containing the sample. The
instrument of the invention includes a resilient plug member which
is inserted down into the receptacle, and which has an opening
therein that permits the serum to pass through the plug member as
it is moved down through the serum in the receptacle. The plug
preferably has a filter across the opening which permits the serum,
but not the cellular material, to pass through the opening as the
plug is pushed down into the tubular receptacle. A hollow rigid rod
extends upwardly from the plug, and the rod is removably attached
to the plug to serve as a conduit for the serum flowing through the
opening in the plug. The rod also serves as a handle to permit the
plug to be pushed down into the serum in the tubular receptacle and
subsequently to be pulled up towards the mouth of the receptacle. A
label may be attached to the instrument which remains in the
tubular receptacle for labeling purposes after the instrument has
been removed. The label may be coded for machine reading.
Inventors: |
Bowen; John G. (South Pasadena,
CA) |
Family
ID: |
23213140 |
Appl.
No.: |
05/312,817 |
Filed: |
December 7, 1972 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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161696 |
Jul 12, 1971 |
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Current U.S.
Class: |
210/94; 210/518;
210/776; 422/918 |
Current CPC
Class: |
B01D
33/01 (20130101); B01L 3/5021 (20130101); G01N
33/491 (20130101) |
Current International
Class: |
B01L
3/14 (20060101); B01D 33/01 (20060101); B01D
33/00 (20060101); G01N 33/49 (20060101); B01d
021/24 () |
Field of
Search: |
;210/85,94,406,516-518,DIG.23,359 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Adee; John
Attorney, Agent or Firm: Beecher; Keith D.
Parent Case Text
This application is a continuation-in-part of Copending Application
Ser. No. 161,696, filed July 12, 1971, now abandoned.
Claims
What is claimed is:
1. An instrument for separating a liquid in an elongated tubular
shaped receptacle, or the like, from solids dispersed to the bottom
of the receptacle, including: a resilient plug member having an
outer periphery configured to fit snugly with the inner surface of
the receptacle and having an opening therein; a rigid tubular
member affixed to said plug member and extending axially therefrom
to provide a conduit for liquid passing through said opening in
said plug member, and also to provide a handle for moving said plug
member up and down within said receptacle, a detachable label
member attached to said plug member, in which said label member
includes a peripheral lip for engaging the end of the tubular
shaped receptacle when the plug member is inserted down into the
receptacle to cause the label member to be detached from said plug
member and to be mounted at the upper end of said tubular shaped
receptacle.
2. The instrument defined in claim 1, in which said label is
mounted externally of said tubular shaped receptacle.
3. The instrument defined in claim 1, in which said label is
mounted internally of said tubular shaped receptacle.
Description
BACKGROUND OF THE INVENTION
The examination of blood samples in a clinical laboratory usually
requires the blood serum to be separated from the cellular material
which is suspended in whole blood. For that reason, it is customary
to place the whole blood samples in test tubes, or similar
elongated receptacles, and to subject the samples to a centrifugal
force to cause the cells to be dispersed to the bottom of the
tubular receptacle. Then, it is usual in the prior art to provide a
skimmer for separating the serum in the test tube from the cellular
material.
For example, such an instrument is described in U. S. Pat. No.
3,355,098; Farr. The present invention is intended to be an
improvement over the unit described in the aforesaid patent, in
that it accomplishes the purpose of the Farr unit without the need
for a separate plastic tube, as is required in the unit described
in the Farr patent. It is usual to make such a tube out of
butyrate, since butyrate is not susceptible to breakage, and is
inexpensive. However, butyrate interferes with the serum in time
and it also transpires moisture.
The instrument of the present invention is advantageous as compared
with the unit described in the patent, since it does not require a
separate tube, and since it is adapted to be fitted directly into
the test tube in which the blood sample is contained. This feature
not only provides for a less expensive instrument, as compared with
the unit of the patent, but also one which does not require
butyrate tubing, or the like, and which has other inherent
improvements which will become evident as the present description
proceeds.
Although the instrument of the invention is primarily concerned
with the separation of serum or plasma from centrifuged clotted, or
whole blood specimens, contained, for example, in a usual glass
test tube; the device has general utility in the separation of any
liquid from any particulate matter dispersed in the bottom of the
receptacle containing the liquid and particulate matter.
The invention provides in general therefore, an instrument for
separating a liquid from dispersed solids suspended therein. In
particular, the invention provides an instrument for separating
blood serum from cellular bodies which have been dispersed to the
bottom of the receptacle containing the mixture.
In a second embodiment, a label is attached to the instrument which
remains in the receptacle after the separation has been effectuated
for labelling purposes.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an elevation of a test tube containing serum and cellular
material, in which the cellular material has been dispersed to the
bottom of the test tube, for example, by centrifuging; and showing
an instrument representing one embodiment of the present invention
inserted into the test tube;
FIG. 2 is a side view of one of the components of the instrument of
the invention shown in FIG. 1;
FIG. 3 shows the instrument of the invention in a test tube, and
used for a slightly different purposes from that of FIG. 1, and in
which the serum is actually transposed into a second
receptacle;
FIG. 4 is a cross-section of a second component of the instrument
of the invention;
FIG. 5 shows the manner in which the instrument of the invention
may be used in a multiplicity of test tubes, so as to cause the
serum in the test tubes to be established at a constant level, for
automatic machinery, or the like;
FIG. 6 shows a second embodiment in which a plastic cap is attached
to the instrument to serve as a label; and
FIGS. 7, 8 and 9 show different manners in which the label of FIG.
6 may be used to identify different serum samples.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
As shown in FIG. 1, a blood sample is contained in a tubular
receptacle, such as a test tube 10, and has been subjected to a
centrifuge action so that its red cells are dispersed to the bottom
of the tube, and the serum appears as a clear liquid disposed over
the red cells. The device of the invention in the embodiment of
FIG. 1, includes a plug member 12 which is formed of rubber, or
equivalent resilient material.
As shown in FIG. 4, for example, the plug member 12 has an opening
extending through it, and a filter 14 is mounted at the mouth of
the opening. The filter 14 serves to pass the serum, but to prevent
the passage of the red cells, or other cellular material, through
the plug 12. The filter 14 may be composed, for example, of
polypropylene felt, which has openings of the order of 3 microns,
and which is effective to impede the passage of the red blood cells
which have a particle size of the order of 7 microns. However,
other appropriate filters may be used, composed, for example, of
nylon, stainless steel screen, Teflon, paper of the like.
The device of the invention in the illustrated embodiment also
includes a hollow elongated rigid member 16 which may be composed,
for example, of aluminum, or any other suitable material. The
elongated member 16, as shown in FIG. 2, has an end portion 16a
which is adapted to be threaded into the plug 12. The member 16
serves as a handle and as a conduit for the liquid passed through
the filter 14 and through the opening in the plug 12. The liquid
emerges from the elongated member 16 through a flexible tubular
member 18 affixed to the upper end 16b of the rigid member.
The rigid elongated member 16 is also used as a handle to push the
plug 12 down into the test tube 10, and to pull the plug up and out
of the test tube. As the plug 12 is moved down into the test tube,
the serum passes through the filter 14 in the plug and up through
the hollow interior of the rod 16. The flexible tube 18 may be
inserted into the mouth of the tube 10, so that as the plug 12 is
pushed by the handle 16 down into the serum, the serum is passed
through the tube 18 into the upper part of the test tube.
Alternately, and as shown in FIG. 1, the tube 18 may be inserted
into a second test tube 30, so that the serum may be transferred
directly from the test tube 10 into the second test tube.
After the plug 12 has been pushed down to the position shown in
FIG. 1 so that it is in the vicinity of the red cells, with the
serum disposed above it, the handle 16 may be removed by unscrewing
it from the plug 12. Then, the top of the test tube 10 may be
plugged by an appropriate stopper, and the test tube may be sent
through the mail, or by any other means, to an appropriate
receiving station. Alternatively, the test tube 10 may be placed in
an automatic machine, so that the serum at the top of the plug 12
may be sampled for test purposes. In this respect, most present day
automatic machines require the levels of the specimens to be
essentially at the same height. This may be achieved by the device
of the invention, and by setting the plugs 12 at different levels
in different test tubes, such as designated A, B and C in FIG. 5,
so that the actual level of the serum will be the same in each of
the tubes.
In the embodiment of FIG. 6, a label 20 in the form, for example,
of a plastic cup is mounted on the skimmer adjacent, for example,
the upper end of the plug 12. The label may have identifying
numbers formed on it; or coded indicia, for example, of the
magnetic type, may be provided on the label, for machine reading of
the sample.
The label 20 may be formed with an external peripheral lip 21, so
that when the skimmer is inserted into the tubular receptacle 10,
the lip engages the upper edge of the receptacle, and the label
becomes detached, as designated 20a in FIG. 7. The label is now
positioned inside the tubular receptacle 10, so that its surface is
protected. However, its indications may be observed through the
transparent tubular receptacle, and/or its magnetic code may be
sensed by an appropriate machine sensor through the wall of the
receptacle.
As an alternative, the label 20 may be provided with an inwardly
extending lip. Such a lip 22, as shown in FIG. 8, may have a
diameter slightly larger than the outer diameter of the tubular
receptacle 10. The latter embodiment, as represented 20b, provides
for the label to be supported externally of the tubular member 10.
This may be desirable in some instances where the label may be
susceptible to causing contamination of the serum within the
receptacle.
The embodiments of FIGS. 7 and 8 are advantageous for machine
reading, since the labels are automatically detached from the
skimmer instrument when it is inserted into the tubular receptacle.
When detached, the labels are all supported at the same level on
the receptacle for convenient machine reading. However, if desired,
the labels may be permanently attached to the plug 12, as
designated 20c in FIG. 9, to remain with the plug within the
receptacle after the handle 16 has been removed.
The invention provides, therefore, a simple and inexpensive
instrument that may be used to skim serum from a first cellular
matter in the bloodstream, and which performs the operation
efficiently and simply.
While particular embodiments of the invention have been shown and
described, modifications may be made, and it is intended in the
following claims to cover all such modifications which come within
the spirit and scope of the invention.
* * * * *