U.S. patent number 3,902,115 [Application Number 05/400,986] was granted by the patent office on 1975-08-26 for self-cleaning aperture tube for coulter study apparatus and electrolyte supply system therefor.
This patent grant is currently assigned to Coulter Electronics, Inc.. Invention is credited to Wallace H. Coulter, Guenter Ginsberg, Thomas J. Godin, Walter R. Hogg, Oscar Proni.
United States Patent |
3,902,115 |
Hogg , et al. |
August 26, 1975 |
**Please see images for:
( Certificate of Correction ) ** |
Self-cleaning aperture tube for coulter study apparatus and
electrolyte supply system therefor
Abstract
A two chamber aperture tube for obtaining signals from particles
suspended in a fluid which passes through a scanning aperture. The
suspension enters an aperture in an inlet chamber and passes
thereafter to an outlet chamber in fluid connection with the inlet
chamber. The inlet chamber of the tube is connected to a source of
clean electrolyte; the outlet chamber is connected to a waste
collecting container. A vacuum is applied to the collecting
container to cause clean electrolyte to be drawn through the inlet
chamber and wash behind the aperture simultaneously with passage of
the suspension through the aperture. A restriction in the path of
flow of the clean electrolyte causes the flow velocity thereof to
increase behind the aperture and ensure that proper signals from
all particles in the suspension are obtained.
Inventors: |
Hogg; Walter R. (Miami Lakes,
FL), Coulter; Wallace H. (Miami Springs, FL), Ginsberg;
Guenter (Miami, FL), Proni; Oscar (Hollywood, FL),
Godin; Thomas J. (Hollywood, FL) |
Assignee: |
Coulter Electronics, Inc.
(Hialeah, FL)
|
Family
ID: |
23585797 |
Appl.
No.: |
05/400,986 |
Filed: |
September 26, 1973 |
Current U.S.
Class: |
324/71.1 |
Current CPC
Class: |
G01N
15/12 (20130101); G01N 15/1218 (20130101); G01N
1/38 (20130101) |
Current International
Class: |
G01N
15/10 (20060101); G01N 15/12 (20060101); G01N
1/38 (20060101); G01n 027/00 () |
Field of
Search: |
;324/71CP ;73/432PS |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Smith; Alfred E.
Assistant Examiner: Hille; Rolf
Attorney, Agent or Firm: Silverman & Cass, Ltd.
Claims
What it is desired to secure by Letters Patent of the United States
is:
1. In a particle measuring apparatus including a vessel for
containing a body of particulate liquid suspension to be tested, an
aperture tube extending into said vessel and including an aperture,
fluid moving means for establishing pressure differentials and
adapted for moving the suspension from the vessel through the
aperture into and through the aperture tube to a waste collection
container, a first electrode in the vessel and a second electrode
in the aperture tube to establish an electrical field in the
aperture between said vessel and the aperture tube, means including
elecrical leads connected to the electrodes and adapted to extend
connections to a detector to respond to electrical measuring
signals produced across said electrodes with passage of particles
through said aperture, the aperture tube having an inlet chamber
adapted for fluid connection with a source of particle free liquid,
said inlet chamber having said aperture in fluid communication on
one side thereof with the suspension in the vessel to permit
passage of the suspension through the aperture into the inlet
chamber, there being a zone in the aperture tube proximate to and
downstream of the aperture in which spurious signals may normally
be produced, an outlet chamber in fluid connection with said inlet
chamber, means for connecting said outlet chamber to said fluid
moving means and said waste collection container, means for
initially filling the inlet and outlet chambers with particle free
liquid; the improvement comprising, the outlet chamber being formed
within the inlet chamber, said chambers having a common closed
bottom wall, said aperture tube having a restriction in the path of
flow of said particle free liquid to cause the flow velocity
thereof to increase in the spurious signal producing zone and
continuously to wash the zone simultaneously with passage of the
suspension through the aperture such that particles which have been
measured within the aperture and thereafter passing out of the same
immediately are swept out of the spurious signal producing zone by
the particle free liquid and moved into the outlet chamber.
2. The invention as claimed in claim 1 in which said restriction is
an orifice formed in the wall of the outlet chamber in
closely-spaced registry with said aperture.
3. The invention as claimed in claim 2 in which the aperture is
formed in a wafer which is fused to the wall of the inlet chamber
and the orifice is formed on a raised dimple on the wall of the
outlet chamber.
4. The invention as claimed in claim 2 in which the aperture and
orifice are formed in wafers which are respectively fused to the
chamber walls.
5. The invention as claimed in claim 2 in which the aperture is
formed in a wafer which is fused to the wall of the inlet chamber
and the orifice is formed on an upstanding jewel which is fused to
the wall of the outlet chamber.
6. In a particle measuring apparatus including a vessel for
containing a body of particulate liquid suspension to be tested, an
aperture tube extending into said vessel and including an aperture,
fluid moving means for establishing pressure differentials and
adapted for moving the suspension from the vessel through the
aperture into and through the aperture tube to a waste collection
container, a first electrode in the vessel and a second electrode
in the aperture tube to establish an electrical field in the
aperture between said vessel and the aperture tube, means including
electrical leads connected to the electrodes and adapted to extend
connections to a detector to respond to electrical measuring
signals produced across said electrodes with passage of particles
through said aperture, the aperture tube having an inlet chamber
adapted for fluid connection with a source of particle free liquid,
said inlet chamber having said aperture in fluid communication on
one side thereof with the suspension in the vessel to permit
passage of the suspension through the aperture into the inlet
chamber, there being a zone in the aperture tube proximate to and
downstream of the aperture in which spurious signals may normally
be produced, an outlet chamber in fluid connection with said inlet
chamber, means for connecting said outlet chamber to said fluid
moving means and said waste collection container, means for
initially filling the inlet and outlet chambers with particle free
liquid; the improvement comprising, the inlet chamber including a
first tube and a connecting tube formed normal to the first tube,
said outlet chamber being in fluid connection with the connecting
tube, said aperture being formed in the connection tube, said
aperture tube hairing an orifice formed in the wall of the first
tube opening into the connection tube, said orifice being in the
path of flow of said particle free liquid to cause the flow
velocity thereof to increase in the spurious signal producing zone
and continuously to wash and zone simultaneously with passage of
the suspension through the aperture such that particles which have
been measured within the aperture and thereafter passing out of the
same immediately are swept out of the spurious signal producing
zone by the particle free liquid and moved into the outlet
chamber.
7. In a particle measuring apparatus including a vessel for
containing a body of particulate liquid suspension to be tested, an
aperture tube extending into said vessel and including an aperture,
fluid moving means for establishing pressure differentials and
adapted for moving the suspension from the vessel through the
aperture into and through the aperture tube to a waste collection
container, a first electrode in the vessel and a second electrode
in the aperture tube to establish an electrical field in the
aperture between said vessel and the aperture tube, means including
electrical leads connected to the electrodes and adapted to extend
connections to a detector to respond to electrical measuring
signals produced across said electrodes with passage of particles
through said aperture, the aperture tube having an inlet chamber
adapted for fluid connection with a source of particle free liquid,
said inlet chamber having said aperture in fluid communication on
one side thereof with the suspension in the vessel to permit
passage of the suspension through the aperture into the inlet
chamber, there being a zone in the aperture tube proximate to and
downstream of the aperture in which spurious signals may normally
be produced, an outlet chamber in fluid connection with said inlet
chamber, means for connecting said outlet chamber to said fluid
moving means and said waste collection container, means for
initially filling the inlet and outlet chambers with particle free
liquid; the improvement comprising, the aperture tube being of
generally U-shaped configuration with one leg forming the inlet
chamber and the other leg forming the outlet chamber, said aperture
tube having a restriction in the path of flow of said particle free
liquid to cause the flow velocity thereof to increase in the
spurious signal producing zone and continuously to wash the zone
simultaneously with passage of the suspension through the aperture
such that particles which have been measured within the aperture
and thereafter passing out of the same immediately are swept out of
the spurious signal producing zone by the particle free liquid and
moved into the outlet chamber.
8.
The invention as claimed in claim 7 in which said restriction is a
generally V-shaped deformation in the wall of the tube extending
therewithin opposite the aperture.
9. In a particle measuring apparatus including a vessel for
containing a body of particulate liquid suspension to be tested, an
aperture tube extending into said vessel and including an aperture,
fluid moving means for establishing pressure differentials and
adapted for moving the suspension from the vessel through the
aperture into and through the aperture tube to a waste collection
container, a first electrode in the vessel and a second electrode
in the aperture tube to establish an electrical field in the
aperture between said vessel and the aperture tube, means including
electrical leads connected to the electrodes and adapted to extend
connections to a detector to respond to electrical measuring
signals produced across said electrodes with passage of particles
through said aperture, the aperture tube having an inlet chamber
adapted for fluid connection with a source of particle free liquid,
said inlet chamber having said aperture in fluid communication on
one side thereof with the suspension in the vessel to permit
passage of the suspension through the aperture into the inlet
chamber, there being a zone in the aperture tube proximate to and
downstream of the aperture in which spurious signals may normally
be produced, an outlet chamber in fluid connection with said inlet
chamber, means for connecting said outlet chamber to said fluid
moving means and said waste collection container, means for
initially filling the inlet and outlet chambers with particle free
liquid; the improvement comprising, the outlet chamber being a
capillary tube formed within the inlet chamber, the inlet chamber
having a closed bottom, the outlet chamber terminating at the
closed bottom of the inlet chamber at an open end positioned below
the aperture, said aperture tube having a restriction in the path
of flow of said particle free liquid to cause the flow velocity
thereof to increase in the spurious signal producing zone and
continuously to wash the zone simultaneously with passage of the
suspension through the aperture such that particles which have been
measured within the aperture and thereafter passing out of the same
immediately are swept out of the spurious signal producing zone by
the particle free liquid and moved into the outlet chamber.
10. The invention as claimed in claim 9 in which said restriction
is a generally V-shaped deformation in the wall of the inlet
chamber opposite the aperture.
11. In a particle measuring apparatus including a vessel for
containing a body of particulate liquid suspension to be tested, an
aperture tube extending into said vessel and including an aperture,
fluid moving means for establishing pressure differentials and
adapted for moving the suspension from the vessel through the
aperture into and through the aperture tube to a waste collection
container, a first electrode in the vessel and a second electrode
in the aperture tube to establish an electrical field in the
aperture between said vessel and the aperture tube, means including
electrical leads connected to the electrodes and adapted to extend
connections to a detector to respond to electrical measuring
signals produced across said electrodes with passage of particles
through said aperture, the aperture tube having an inlet chamber
adapted for fluid connection with a source of particle free liquid,
said inlet chamber having said aperture in fluid communication on
one side thereof with the suspension in the vessel to permit
passage of the suspension through the aperture into the inlet
chamber, there being a zone in the aperture tube proximate to and
downstream of the aperture in which spurious signals may normally
be produced, an outlet chamber in fluid connection with said inlet
chamber, means for connecting said outlet chamber to said fluid
moving means and said waste collection container, means for
initially filling the inlet and outlet chambers with particle free
liquid; the improvement comprising, the outlet chamber being formed
within the inlet chamber, the inlet chamber having a closed bottom,
the outlet chamber terminating at the closed bottom of the inlet
chamber at an open end positioned below the aperture, said aperture
tube having a restriction in the path of flow of said particle free
liquid to cause the flow velocity thereof to increase in the
spurious signal producing zone and continuously to wash the zone
simultaneously with passage of the suspension through the aperture
such that particles which have been measured within the aperture
and thereafter passing out of the same immediately are swept out of
the spurious signal producing zone by the particle free liquid and
moved into the outlet chamber.
12. The invention as claimed in claim 11 in which said restriction
is a protrusion in the wall of the outlet chamber opposite the
aperture.
13. The invention as claimed in claim 12 in which longitudinal
portions of the walls of the chambers are disposed in abutting
relationship and the wall of the outlet chamber opposite the
abutting wall is deformed in the shape of a longitudinal channel to
provide said inlet chamber.
14. An aperture tube for use in particle measuring apparatus
including a container of particulate liquid suspension into which
the aperture tube extends, said tube comprising, an inlet chamber,
an outlet chamber in fluid connection with the inlet chamber, said
outlet chamber being formed within the inlet chamber, the chambers
having a common closed bottom wall, the inlet chamber having an
aperture adapted to be in communication on one side thereof with
the liquid suspension, there being a zone in the aperture tube
proximate to and downstream of the aperture in which spurious
signals may normally be produced, means for connecting the inlet
chamber to a source of particle free liquid, means for connecting
the outlet chamber to fluid moving means to move the suspension
from the container through the aperture into the spurious signal
producing zone, the tube having a restriction in the path of flow
of the particle free liquid to cause the flow velocity thereof to
increase in the spurious signal producing zone and continuously
wash the zone simultaneously with passage of the suspension through
the aperture such that particles which have passed through the
aperture immediately are swept out of the spurious signal producing
zone by the particle free liquid and moved into the outlet
chamber.
15. The invention as claimed in claim 14 in which said restriction
is an orifice formed in the wall of the outlet chamber in
closely-spaced registry with said aperture.
16. The invention as claimed in claim 15 in which the aperture is
formed in a wafer which is fused to the wall of the inlet chamber
and the orifice is formed on a raised dimple on the wall of the
outlet chamber.
17. The invention as claimed in claim 15 in which the aperture and
orifice are formed in wafers which are respectively fused to the
chamber walls.
18. The invention as claimed in claim 15 in which the aperture is
formed in a wafer which is fused to the wall of the inlet chamber
and the orifice is formed on an upstanding jewel which is fused to
the wall of the outlet chamber.
19. An aperture tube for use in particle measuring apparatus
including a container or particulate liquid suspension into which
the aperture tube extends, said tube comprising, an inlet chamber,
an outlet chamber in fluid connection with the inlet chamber, the
inlet chamber having an aperture adapted to be in communcation on
one side thereof with the liquid suspension, there being a zone in
the aperture tube proximate to and downstream of the aperture in
which spurious signals may normally be produced, means for
connecting the inlet chamber to a source of particle free liquid,
means for connecting the outlet chamber to fluid moving means to
move the suspension from the container through the aperture into
the spurious signal producing zone, the tube having a restriction
in the path of flow of the particle free liquid, the inlet chamber
including a first tube and a connecting tube formed normal to the
first tube, said outlet chamber being in fluid connection with the
connecting tube, said aperture being formed in the connection tube,
and said restriction is an orifice formed in the wall of the first
tube opening into the connection tube, whereby the flow velocity of
the particle free liquid increases in the spurious signal producing
zone and continuously washes the zone simultaneously with passage
of the suspension through the aperture such that particles which
have passed through the aperture immediately are swept out of the
spurious signal producing zone by the particle free liquid and
moved into the outlet chamber.
20. An aperture tube for use in particle measuring apparatus
including a container of particulate liquid suspension into which
the aperture tube extends, said tube comprising, an inlet chamber,
an outlet chamber in fluid connection with the inlet chamber, the
tube being of generally U-shaped configuration with one leg forming
the inlet chamber and the other leg forming the outlet chamber, the
inlet chamber having an aperture adapted to be in communication on
one side thereof with the liquid suspension, there being a zone in
the aperture tube proximate to and downstream of the aperture in
which spurious signals may normally be produced, means for
connecting the inlet chamber to a source of particle free liquid,
means for connecting the outlet chamber to fluid moving means to
move the suspension from the container through the aperture into
the spurious signal producing zone, the tube having a restriction
in the path of flow of the particle free liquid to cause the flow
velocity thereof to increase in the spurious signal producing zone
and continuously wash the zone simultaneously with passage of the
suspension through the aperture such that particles which have
passed through the aperture immediately are swept out of the
spurious signal producing zone by the particle free liquid and
moved into the outlet chamber.
21. The invention as claimed in claim 19 in which said restriction
is a generally V-shaped deformation in the wall of the tube
extending therewithin opposite the aperture.
22. An aperture tube for use in particle measuring apparatus
including a container of particulate liquid suspension into which
the aperture tube extends, said tube comprising, an inlet chamber,
a capillary tube outlet chamber formed within the inlet chamber and
in fluid connection therewith, the inlet chamber having a closed
bottom and an aperture adapted to be in communication on one side
thereof with the liquid suspension, the outlet chamber terminating
at the closed bottom of the inlet chamber at an open end positioned
below the aperture, there being a zone in the aperture tube
proximate to and downstream of the aperture in which spurious
signals may normally be produced, means for connecting the inlet
chamber to a source of particle free liquid, means for connecting
the outlet chamber to fluid moving means to move the suspension
from the container through the aperture into the spurious signal
producing zone, the tube having a restriction in the path of flow
of the particle free liquid to cause the flow velocity thereof to
increase in the spurious signal producing zone and continuously
wash the zone simultaneously with passage of the suspension through
the aperture such that particles which have passed through the
aperture immediately are swept out of the spurious signal producing
zone by the particle free liquid and moved into the outlet
chamber.
23. The invention as claimed in claim 22 in which said restriction
is a generally V-shaped deformation in the wall of the inlet
chamber opposite the aperture.
24. An aperture tube for use in particle measuring apparatus
including a container of particulate liquid suspension into which
the aperture tube extends, said tube comprising, an inlet chamber,
an outlet chamber formed within the inlet chamber and in fluid
connection therewith, the inlet chamber having a closed bottom and
an aperture adapted to be in communication on one side thereof with
the liquid suspension, the outlet chamber terminating at the closed
bottom of the inlet chamber at an open end positioned below the
aperture, there being a zone in the aperture tube proximate to and
downstream of the aperture in which spurious signals may normally
be produced, means for connecting the inlet chamber to a source of
particle free liquid, means for connecting the outlet chamber to
fluid moving means to move the suspension from the container
through the aperture into the spurious signal producing zone, the
tube having a restriction in the path of flow of the particle free
liquid to cause the flow velocity thereof to increase in the
spurious signal producing zone and continuously wash the zone
simultaneously with passage of the suspension through the aperture
such that particles which have passed through the aperture
immediately are swept out of the spurious signal producing zone by
the particle free liquid and moved into the outlet chamber.
25. The invention as claimed in claim 24 in which said restriction
is a protrusion in the wall of the outlet chamber opposite the
aperture.
26. The invention as claimed in claim 25 in which longitudinal
portions of the walls of the chambers are disposed in abutting
relationship and the wall of the outlet chamber opposite the
abutting wall is deformed in the shape of a longitudinal channel to
provide said inlet chamber.
27. An electrolyte supply system for particle measuring apparatus
in which an aperture tube is suspended in a vessel for containing a
body of particulate liquid suspension to be tested, the tube having
an aperture to permit passage of the suspension from the container
into the tube, the apparatus including a first electrode in the
vessel and a second electrode in the aperture tube to establish an
electrical field in the aperture between the vessel and the
aperture tube, and means including electrical leads connected to
the electrodes and adapted to extend connections to a detector to
respond to electrical measuring signals produced across the
electrodes with passage of particles through said aperture, said
system comprising, the aperture tube having an inlet chamber for
introduction of particle free electrolyte, an outlet chamber in
fluid connection with the inlet chamber, the aperture tube being
mounted at the end opposite the suspended end in a coupling block,
an electrolyte reservoir in fluid communication with the inlet
chamber, a waste container in fluid communication with the outlet
chamber, and fluid moving means connected to the waste container,
whereby the fluid moving means will cause electrolyte to pass from
the reservoir through the inlet and outlet chambers and into the
container and simultaneously will draw suspension through the
aperture.
28. A system as claimed in claim 27 in which the second electrode
is the signal electrode for the particle measuring apparatus, the
system including an electrolyte drip chamber and supply conduit
interposed between the reservoir and inlet chamber, the drip
chamber and conduit being shielded with an electrical insulating
member.
29. A system as claimed in claim 27 in which the coupling block is
separable into two portions to permit removal of the aperture
tube.
30. A system as claimed in claim 27 in which the outlet chamber is
connected to the top of the waste container and the waste container
is a waste drip chamber having a drain conduit provided at the
bottom thereof terminating below the surface of the waste
electrolyte drawn into the waste drip chamber such that the
electrical connection between the electrolyte path through the
drain conduit and the outlet chamber will be broken by reason of
droplet formation of the electrolyte as it enters the waste drip
chamber.
31. The system as claimed in claim 27 in which the volume of
electrolyte in the reservoir is maintained constant by continuous
supply from an electrolyte source.
32. The system as claimed in claim 27 in which the fluid moving
means comprise a source of vacuum.
Description
CROSS-REFERENCE TO RELATED PATENTS
The structure to which this invention applies is of the type
described and disclosed in U.S. Pat. No. 3,299,354 (herein called
"the Related Patent") issued Jan. 17, 1967 for "Aperture Tube
Structure for Particle Study Apparatus" to one of the applicants
herein, and owned by the same assignee as the invention herein. The
said Related Patent is incorporated herein as a part hereof by
specific reference.
The herein invention also is related to and is an improvement upon
the structure disclosed in U.S. Pat. No. 3,746,976 issued July 17,
1973 for "Self-Cleaning Aperture Tube for Coulter Study Apparatus",
the applicant therein being one of the inventors herein, and owned
by the same assignee as this invention.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to the art of studying the
physical properties of particles carried in suspension and more
particularly is concerned with improved apparatus for obtaining
signals from particles passing through a scanning aperture without
extraneous interference from other particles.
2. Description of the Prior Art
The structure disclosed in the Related Patent substantially
decreases the possibility of undesirable spurious particle reading
and count signals which sometimes occured in prior art devices.
This was accomplished by replacing the so-called aperture tube of
prior art structures with a pair of chambers having an
interconnection for separating the electrical and mechanical
effects produced by particles passing through the aperture.
Particles passing through the aperture of the apparatus immediately
were transported away from the proximity of the aperture so that
there was little or no chance of spurious signals resulting from
said particles.
One of the objects of the invention disclosed in the Related Patent
was to provide an aperture tube which was self-cleaning in that the
suspension in the immediate vicinity of the aperture was kept free
of extraneous particles. As acknowledged in the patent, however,
eddy currents of fluid in the aperture tube at the downstream end
of the primary bore could occur, and these eddy currents swirled
into the secondary bore immediately adjacent the primary bore. It
was believed that the fluid would be stagnant liquid substantially
devoid of particles, hence not introducing appreciable extraneous
signals, but while this was largely true, the action was deemed not
sufficient to satisfy the more critical demands of today's
technology. A small percentage of particles was not caught by the
orifice in the elongate neck of the second chamber and these
sometimes produced extraneous signals by virture of the eddy
currents at the bottom of the central chamber of the aperture
tube.
For purposes of resolving the aforesaid problems with regard to
extraneous signals, the invention disclosed in U.S. Pat. No.
3,746,976 provides a self-cleaning aperture tube as disclosed in
the Related Patent, with the addition of a pump device interposed
between the first and second chambers to produce a closed system in
which there are no inlets or outlets other than the primary bore in
the first chamber. The pump operates to draw the particle
suspension up through the second chamber and force the same back
into the first chamber, completing a circuit around this path and
creating a sheath flow at the orifice. The flow created by the pump
is such as to ensure that all particles introduced into the
aperture tube are caught by the orifice of the second chamber so as
to prevent the occurrence of extraneous signals.
The invention of U.S. Pat. No. 3,746,976 satisfactorily eliminates
the extraneous signal problems inherent in the structure of the
Related Patent. In so doing, however, the structure incorporates a
pump and filter through which electrolyte is recirculated to
achieve the cleaning flow. Further, the structure of U.S. Pat. No.
3,746,976 includes a relatively fragile and cumbersome aperture
tube in which the chambers thereof are separated along a
substantial portion of the tube.
SUMMARY OF THE INVENTION
The present invention provides an improved selfcleaning aperture
tube for a Coulter study apparatus of the type disclosed in the
Related Patent. (The mark "Coutler" is the registered trademark,
Registration No. 995,825 of Coulter Electronics, Inc. of Hialeah,
Fla. The aperture tube of the herein invention eliminates the
disadvantages of the tube disclosed in U.S. Pat. No. 3,746,976 in
which one chamber has a branch or lateral diversion which passes
out of a second chamber and returns again. Further, the present
invention provides a system which supplies fresh clean electrolyte
from a reservoir and eliminates the need for recirculating the
electrolyte through a pump and filter as in the structure of U.S.
Pat. No. 3,746,976.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional view through a system constructed in
accordance with the invention, including some diagrammatic
representation of associated apparatus for the purpose of
explaining the same;
FIG. 2 is a fragmentary enlarged sectional view through the
aperture tube of the invention showing the details thereof;
FIG. 3 is a view similar to that of FIG. 2 illustrating a modified
construction of the aperture tube;
FIG. 4 is a view similar to that of FIG. 2 illustrating a further
modified construction of the aperture tube;
FIG. 5 is a fragmentary enlarged sectional view of another form of
aperture tube for use with the structure of FIG. 1;
FIG. 6 is a fragmentary enlarged sectional view of a still further
form of aperture tube for use with the structure of the
invention;
FIG. 7 is a fragmentary enlarged sectional view of another
alternate embodiment of the aperture tube for use with the
structure of the invention;
FIG. 8 is a sectional view taken along the line 8--8 of FIG. 7 in
the direction indicated generally;
FIG. 9 is a sectional view taken along the line 9--9 of FIG. 7 in
the direction indicated generally;
FIG. 10 is a fragmentary enlarged sectional view of an additional
alternate embodiment of the aperture tube for use with the
structure of FIG. 1;
FIG. 11 is a sectional view taken along the line 11--11 of FIG. 10
in the direction indicated generally;
FIG. 12 is a sectional view taken along the line 12--12 of FIG. 10
in the direction indicated generally; and
FIG. 13 is a sectional view taken along the line 13--13 of FIG. 10
in the direction indicated generally.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The apparatus with which the structure of the invention is intended
for use is known as the Coulter electronic particle analyzing
device. The Coulter device and its principle of operation is
referred to with particularity in the Related Patent. Since the
Related Patent is incorporated herein as a part hereof by specific
reference, the disclosure thereof will not be repeated except in
instances where understanding of the invention herein will be
enhanced.
Referring to FIG. 1, the structure of the invention is indicated by
the reference number 10. A dual chamber aperture tube 12 including
a first chamber 13 which is formed upon and completely surrounds a
second chamber 18, is suspended within a vessel or beaker 38. A
measuring aperture 14 is formed in the wall of the first chamber 13
near the lower end thereof; a cleaning orifice 16 is formed in the
wall of the second chamber 18 in registry with the aperture 14. The
vessel 38 retains a body of the sample solution 48 to be drawn
through aperture 14 and orifice 16; electrodes 34 and 36 are
positioned within the aperture tube 12 and vessel 38, respectively,
and are connected to the detector of a Coulter study apparatus
through leads 17 in the manner described in the Related Patent for
purposes of performing an analysis of the sample solution.
Aperture tube 12 is associated with the structure 10 by mounting
same on coupling block 54 which is separable along the juncture
line 56, the two portions 57, 58 of block 54 being secured together
by screws 59. The tube 12 terminates within the block 54 at its
upper end 62. An O-ring 64 is positioned about tube 12 to provide
an air and liquid-tight seal. The tube is secured by cast epoxy
resin to the lower half 57 of block 54 to form an easily mounted
integral assembly. The tube 12 thereby may be replaced readily with
another of the same type in the event of breakage, or with an
alternate form of tube as discussed hereinafter. A conduit 71 with
valve 73' for flushing and purging the tube 12 is connected to the
tube by fitting 70.
Chamber 18 terminates downstream in the upper portion 19 thereof at
a fitting 21 which couples the terminal portion 19 to a conduit 20.
A valve 22 is positioned in conduit 20 and the conduit terminates
at a waste drip chamber or waste container 24. A vacuum source (not
shown) is connected to the waste container 24 by conduit 23. A
waste conduit 42 with valve 43 is provided on the bottom of
container 24.
Chamber 13 forms the upstream portion of structure 10. The upper
port 25 of chamber 13 is connected by couplings and conduits
designated generally 80 through the "choke" or hydraulic resistance
27 to an electrolyte supply drip chamber 29 having access ports 31
and 35, normally closed by valves not shown, and a supply port 33.
Clean electrolyte 28 is supplied to chamber 29 through supply
reservoir 52 which empties into reservoir 26 and is drawn into the
chamber through fluid connection 40 having a valve 30 interposed
therein.
A shield represented by the dashed line 32 is provided electrically
to insulate connecting members 80 and supply drip chamber 29 when
the electrode 34 serves as the signal electrode for the Coulter
study apparatus. This will be the case when more than one aperture
are immersed in the sample bath 48 of vessel 38. If a single
aperture tube 12 is used in the sample bath, the electrode 34 may
be grounded and the electrode 36 may be the signal electrode in
which case the shield 32 may be omitted. Since the electrolyte path
40 between valve 30 and the aperture tube 12 is broken by the drip
chamber 29, it may be grounded and located at any convenient
position regardless which electrode is used as the signal
electrode.
The waste bottle/waste drip chamber 24 will serve one or the other
function depending upon the application and desired mode of
operation of the structure of the invention. If the bottle/chamber
24 has a volume greater than the combined sample and clean "wash"
electrolyte, and the waste is evacuated after each measurement
through tube 42 by opening valve 43, the bottle/chamber 24 will
serve merely as a drip chamber and the electrical connection will
be broken between the electrolyte path through the tube 42 and the
electrolyte path through the tube 20 and valve 22 by means of the
droplet formation indicated at 41. If the valve 43 is not opened
after each measurement cycle, the bottle/chamber 24 must have a
much larger capacity and will serve as a waste bottle.
Operation of the structure 10 is as follows: a vacuum is applied
from the vacuum source through conduit 23, the waste bottle/drip
chamber 24, valve 22 and tubing 20 to the inside chamber 18.
Assuming that the aperture 14 is plugged, suction is applied to the
orifice 16, which in turn sucks liquid up out of reservoir 26 along
a path through fluid connection 40, valve 30, accumulation chamber
29 and connection members 80. This flow of electrolyte creates a
washing action behind the measuring aperture 14. If the measuring
aperture is open as it will be in operation of the structure 10 the
sample 48 will be drawn into the aperture tube 12 at the same time
that electrolyte is passing behind aperture 14. The clean
electrolyte from reservoir 26 will surround the sample coming
through the aperture 14 and prevent particles from straying in the
aperture tube 12, thus eliminating the disadvantageous swirling
effect of eddy currents as in U.S. Pat. No. 3,746,976. The washing
action created by the flow of electrolyte behind the measuring
aperture 14 is such as to ensure that all particles introduced into
the aperture tube are caught by the orifice of the second chamber
18 so as to prevent the occurrence of extraneous signals.
The supply reservoir 52 is illustrated in the form of a livestock
waterer in order to keep the level 37 of clean electrolyte 28 in
reservoir 26 at a constant height. It is necessary to maintain the
pressure drop stable so that the flow rate through the aperture 14
will be relatively constant. Since in the arrangement shown it is
not possible to measure the volume of sample scanned by the
detector, it is mandatory that the flow rates be stable.
It is to be noted that, if desired, the structure of the present
invention may be adapted to a closed-loop circulatory system
similar to that disclosed in U.S. Pat. No. 3,746,976. This could be
accomplished by closing or omitting connection 23, and connecting
waste conduit 42 to fluid connection 40 with a pump and filter
interposed therebetween. The effective operation of the structure
herein would be the same except recirculating electrolyte would
flow through structure 10 instead of clean fluid from reservoir
26.
FIGS. 2, 3 and 4 illustrate three forms of construction of the
aperture tube comprising inner and outer chambers as shown in FIG.
1. In FIG. 2, the orifice 16 is drilled directly into the glass
wall of the second chamber 18. A tungsten point is inserted into
the wall of the inner chamber 18 before it is sealed into the outer
chamber 13. A tiny spot of heat is applied to the intended location
of orifice 16 and the dimple 60 is pushed out by the tungsten point
when the glass gets hot. The dimple subsequently is ground down
flat as shown and the orifice 16 is drilled thereon. The aperture
14 is formed within a wafer which is heat-sealed to the outer
chamber 13 in registry with orifice 16 in a known manner.
In the embodiment shown in FIG. 3, a jewel or sapphire wafer having
the measuring aperture 14' is mounted on the inside of the tubing
which is intended to form the wall of chamber 13'. The hole for the
wafer bearing aperture 14' is picked in the opposite side of the
tube and the wafer is positioned behind the hole. The wafer and the
glass around it are then heated and sealed, such that the wafer is
an integral part of the glass tubing. Similarly a wafer with
orifice 16' is mounted on the outside of a length of smaller
diameter tubing intended to form the inner chamber 18' of the
aperture tube.
In the aperture tube shown in FIG. 4, the aperture 14" is formed
within a wafer positioned on the wall of the outer chamber 13" in
the same manner as that of FIG. 2. The orifice 16" is formed on an
upstanding jewel or sapphire 61 which is fused to the wall of
chamber 18". The effect and operation of this tube is the same as
that of the tube shown in FIG. 2.
After the large bore tubing carrying aperture 14, 14' or 14", and
the small bore tubing carrying the respective orifice 16, 16' or
16" are both fabricated, they are held together in a suitable
fixture or vise so that the aperture and orifice are in registry
with proper spacing between the tubes. The two tubes are then
heat-melted and sealed at the locations 50, 50' or 50" to produce
the aperture tube as shown. It may be desirable to put a graded
seal in both tubes so that the temperature coefficients do not
cause breakage of the aperture tube on cooling. This may be avoided
if the entire structure is made of glass having the same
temperature coefficient as that of the wafer as known in the
art.
As indicated previously, the structure of the invention is such
that aperture tubes of a construction different from tube 12 may be
used by disassembling coupling block 54, removing tube 12 and
positioning a new tube. So long as the upper parts of the new tube
which are retained in block 54 have the same configuration as tube
12 any of a wide variety of tubes may be used.
In FIG. 5 one such interchangeable alternate form of aperture tube
is shown. There is a first tube 113 and a second tube 118. A
relatively narrow connecting tube 130 connects the tubes 113 and
118. An aperture 114 is provided in connecting tube 130 and an
orifice 116 is provided in the wall of tube 113. Coupling members
125, 162, 121, 170 and 173 corresponding to members 24, 62, 21, 70
and 73 shown in FIG. 1 are provided to enable positioning of the
aperture tube assembly on connecting block 54. O-ring 164 seals the
tube in the block in the same manner as O-ring 64 of FIG. 1. An
electrode 134 is located in tube 113 and corresponds to electrode
34.
In operation, after connection in block 54 the circulating flow of
clean electrolyte from reservoir 26 comes down through tube 113,
passes through orifice 116 and connecting tube 130 and then back up
through tube 118 into conduit 20 (FIG. 1). Sample simultaneously is
sucked into aperture 114 and the circulating flow carries the
particles which have been measured from left to right and away from
the measuring zone preventing them from returning to the measuring
zone. The flow through tubes 113 and 118 is kept at a desired rate
by means of the restriction 127 placed upstream of tube 113.
FIGS. 6, 7 and 10 illustrate three further interchangeable
alternate forms of aperture tube which may be used in the structure
10. In each figure the upper elements of the tube are shown with
conduits and fittings corresponding to like elements of the tube 12
to enable placement of the alternate tube in the connecting block
54. These like elements are identified with the same reference
numbers as in FIG. 1 with single, double or triple primes
added.
In FIG. 6 the aperture 214 is positioned in the side of a U tube
213 of small diameter measuring about 2.5 mm. A V-shaped
restriction 280 is formed in the wall of the U tube opposite the
aperture to increase the flow velocity of electrolyte as it passes
behind the aperture. The dimensions of the U tube proximate the
aperture and V-shaped restriction are on the order of about 1 mm.
Clean electrolyte flows down leg 215 and provides a continuous
washing effect behind aperture 214 normal to the aperture axis by
reason of the restriction 280. The wash electrolyte together with
the sample which has been drawn through aperture 214, then leaves
the U tube by passing up leg 217 and out into conduit 20'. The zone
216 immediately below restriction 280 and behind aperture 214 is
roughly equivalent to orifice 16 of aperture tube 12 in that the
fluid present in this zone is used wash electrolyte and sample.
This fluid immediately is carried away from the measuring aperture
214 by reason of increased flow rate behind the restriction
280.
In FIGS. 7, 8 and 9, aperture 314 is positioned on tube 313. A
V-shaped restriction 380 is formed in the wall of tube 313 opposite
the aperture, again for the purpose of increasing the flow velocity
of electrolyte as it passes behind the aperture. A capillary tube
317 is positioned within tube 313 and terminates at the lower end
330 of tube 313 below the aperture opening. Clean electrolyte flows
down tube 313 to provide the continuous washing effect behind
aperture 314 normal to the aperture axis by reason of the
restriction 380. The wash electrolyte together with the sample
which has been drawn through aperture 314 then leaves the aperture
tube by passing up capillary tube 317 and out into conduit 20". The
zone 316 immediately below restriction 380 and behind aperture 314
is roughly equivalent to orifice 16 of aperture tube 12 in that the
fluid present in this zone is used wash electrolyte and sample.
This fluid immediately is carried away from the measuring aperture
314 by reason of increased flow rate behind the restriction 380.
The whole assembly is fitted to a coupling block 54 (not shown) as
described in connection with FIGS. 1 and 5 for the appropriate
liquid and electrical connections.
In the embodiment of FIGS. 10 through 13 aperture 414 is positioned
on tube 413 at a location of reduced diameter. A second tube 417
which is open at the bottom 430 of tube 413 is positioned within
tube 413 with one wall 420 of tube 417 engaging the back wall 422
of tube 413 along the length thereof. The surface 424 of tube 417
opposite wall 420 is deformed in the shape of a longitudinal
channel such that tube 417 is of generally half-moon
cross-sectional configuration. A protrusion 480 is formed in
surface 424 proximate the back side of aperture 414 to provide the
desired increased flow velocity of electrolyte as it passes behind
the aperture. The tube 417 terminates below aperture 414 with space
below the terminal end for passage of fluid up the tube. The
half-moon configuration of tube 417 is such as to divide tube 413
into two portions, a first portion 430 for down-flow of electrolyte
and a second portion 432 for up-flow of electrolyte and sample.
Proximate the location of aperture 414 the inner tube 417 is
completely flat so that wash electrolyte must pass through
countersink 440 behind aperture 414, the countersink being formed
in the wall of tube 413 when the wafer having aperture 414 is
secured to the outside surface of the tube. Another longitudinal
depression is formed in tube 417 below the protrusion 480 to permit
wash fluid to pass out from behind aperture 414. The radial
dimension of the protrusion 480 proximate aperture 414 is as small
as possible in order to cause the cross-sectional area of the
electrolyte between the aperture and electrode to become large as
quickly as possible. Clean electrolyte flows down portion 430 of
tube 413 to provide the washing effect behind aperture 414 as
described. The wash electrolyte and sample which has been drawn
through the aperture then passes up tube 417 along portion 432 and
out into conduit 20'".
The restrictions 280, 380 and 480 behind the aperture of the
embodiments of FIGS. 6, 7 and 10, respectively, are such as to
provide very high electrolyte flow rates without necessitating the
use of large quantities of clean electrolyte. A criterion of
performance satisfied by each of the embodiments disclosed herein
is that the speed of the washing flow of clean electrolyte down
past the measuring aperture is greater than any upward components
of any currents formed behind the aperture thus sweeping particles
which have already been measured out of the sensing zone and
preventing any particles from traveling upwards behind the aperture
into the zone immediately upstream thereof where false pulses may
be created.
Minor variations in the structure and other variations in the
arrangements and size of the various parts may occur to those
skilled in the art without departing from the spirit or
circumventing the scope of the invention as set forth in the
appended claims.
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