U.S. patent number 3,850,369 [Application Number 05/339,403] was granted by the patent office on 1974-11-26 for centrifuge for preparing platelet rich plasma.
This patent grant is currently assigned to Coulter Electronics, Inc.. Invention is credited to Brian S. Bull, Loran V. Melnick, Oscar Proni.
United States Patent |
3,850,369 |
Bull , et al. |
November 26, 1974 |
CENTRIFUGE FOR PREPARING PLATELET RICH PLASMA
Abstract
A centrifuge for production of platelet rich plasma by
accelerated sedimentation of whole blood. The centrifuge is adapted
to apply greater than gravity force laterally, that is,
approximately perpendicular, to the long axis of a thin cylindrical
container partially filled with whole blood. The centrifuge
includes cam actuated timer means cyclically operating a centrifuge
head in which the cylindrical containers are held. Drive means are
provided to rotate the head and said timer means includes means
controlling the coupling of said drive means with said head whereby
said head is driven for a predetermined duration, the drive means
deenergized and the head is uncoupled therefrom to a free
rotational state during which a gradual slowdown is effected to
permit the vertically oriented column of blood to return from the
side of the container to the bottom smoothly and with mixing within
the plasma and cell layers but not between the two layers. Also
provided are alarm means for indicating the expiration of a
predetermined time during which the head is at rest so as to enable
the operator to be certain sufficient time has elapsed to
accomplish the required degree of sedimentation.
Inventors: |
Bull; Brian S. (Loma Linda,
CA), Proni; Oscar (Hollywood, FL), Melnick; Loran V.
(Miami, FL) |
Assignee: |
Coulter Electronics, Inc.
(Hialeah, FL)
|
Family
ID: |
23328849 |
Appl.
No.: |
05/339,403 |
Filed: |
March 8, 1973 |
Current U.S.
Class: |
494/10; 494/16;
494/11 |
Current CPC
Class: |
B04B
13/00 (20130101); B04B 5/0414 (20130101) |
Current International
Class: |
B04B
5/04 (20060101); B04B 5/00 (20060101); B04B
13/00 (20060101); B04b 009/10 () |
Field of
Search: |
;233/26,27,28,23R,24,19R,1R |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Krizmanich; George H.
Attorney, Agent or Firm: Silverman & Cass, Ltd.
Claims
We claim:
1. A centrifuge device comprising a centrifuge head mounted for
rotation, sample holder means arranged on said centrifuge head for
receiving at least one elongate sample container on the
circumference of said centrifuge head, each sample container having
an open end and being oriented on said centrifuge head with its
open end closer to the rotational axis of said centrifuge head and
such that the long axis of said container intersects a plane normal
to said rotational axis at an angle between approximately
70.degree. and 90.degree., drive means including a drive motor, for
rotating said centrifuge head, timing means operative on said drive
means for rotating said centrifuge head in timed cycles and said
drive means including spinner means coaxially mounting said
centrifuge head to enable free rotation of said centrifuge head,
said spinner means having engaging means mounted thereon and said
centrifuge head having depending post means arranged to be engaged
by said engaging means to drive said centrifuge head only when the
spinner means is rotated and to be released therefrom when rotation
of said spinner means ceases, means to effect cessation of rotation
of said spinner means immediately upon de-energization of said
drive motor whereby to permit free rotation of said centrifuge head
on a gradually diminishing rate to assume a rest condition.
2. The centrifuge device as claimed in claim 1 in which said means
to effect cessation of rotation of said spinner means comprises,
first pulley means coupled to said drive motor and arranged to be
driven thereby, second pulley means coupled to said spinner means,
means for transmitting rotational drive between said first and
second pulley means to enable said pulleys to operate substantially
simultaneously whereby said spinner means stops substantially
instantaneously with deenergization of said drive motor.
3. A centrifuge device comprising a centrifuge head mounted for
rotation, sample holder means arranged on said centrifuge head for
receiving at least one elongate sample container on the
circumference of said centrifuge head, each sample container having
an open end and being oriented on said centrifuge head with its
open end closer to the rotational axis of said centrifuge head and
such that the long axis of said centrifuge head and such that the
long axis of said container intersects a plane normal to said
rotational axis at an angle between approximately 70.degree. and
90.degree., drive means including a drive motor, for rotating said
centrifuge head, timing means operative on said drive means for
rotating said centrifuge head in timed cycles and means for
enabling gradual diminishing of the rotation of said centrifuge
head to a rest condition upon deenergization of said motor, said
drive means includes spinner means arranged to drive said
centrifuge head, first pulley means coupled to said drive motor and
arranged to be driven thereby, second pulley means coupled to said
spinner means, means for transmitting rotational drive between said
first and second pulley means to enable said pulleys to operate
substantially simultaneously whereby said spinner means stops
substantially instantaneously with deenergization of said drive
motor, and said spinner means includes spring means mounted for
rotation therewith to place end portions thereof extending
outwardly of said spinner means on rotation thereof, and said
centrifuge head includes depending posts arranged in the rotational
path of said spring means whereby to be drivingly engaged thereby
on rotation of said spinner means, said spring means capable of
being driven by said depending posts inwardly out of said
intercepting path with said depending posts when said spinner means
ceases rotation, thereby permitting said centrifuge head gradually
to diminish its rotation to assume a rest condition on
deenergization of said drive motor.
4. The centrifuge device as claimed in claim 1 in which said timing
means includes a timer motor, first switch means operative on said
drive motor, second switch means operative on said timer motor and
cam means coupled to said timer motor and operative successively on
said first and second switch means whereby to energize said drive
motor for a predetermined time duration thereafter to deenergize
said drive motor and thereafter to deenergize said timer motor.
5. The centrifuge device as claimed in claim 4 and alarm means for
indicating an elapsed time duration, third switch means operative
to energize said alarm means immediately subsequent to expiration
of said elapsed time duration and said cam means also being coupled
to said third switch means to operate same on expiration of said
time duration.
6. The centrifuge device as claimed in claim 5 in which said alarm
means comprises audible buzzer means.
7. The centrifuge device as claimed in claim 5 and indicator lamp
means operable until the expiration of said elapsed time duration
and coupled to said third switch means for deenergization on
closing of said third switch means.
8. The centrifuge device as claimed in claim 6 and indicator lamp
means energized until the expiration of said elapsed time duration
and coupled to said third switch means for deenergization on
closing of said third switch means.
9. The centrifuge device as claimed in claim 1 in which said drive
means operates to rotate said centrifuge head sufficiently to apply
a centrifugal force of about 35 G to each sample container in a
direction traversely of the long axis of said container for a time
period duration less than one minute.
10. The centrifuge device as claimed in claim 1 in which the sample
container is adapted to be filled partially with whole blood.
Description
FIELD OF THE INVENTION
This invention relates generally to centrifugal separation of whole
blood fractions and more particularly, concerns the provision of an
improved centrifuge apparatus for rapid production of platelet rich
plasma from whole blood samples.
CROSS REFERENCE TO RELATED APPLICATIONS
The centrifugal augmentation of rouleaux formation of whole blood
is discussed and apparatus provided in co-pending U.S. Pat.
Applications Ser. Nos. 191,886 and 191,768, both filed on Oct. 22,
1971 and assigned to assignee of this application.
BACKGROUND OF THE INVENTION
The enumeration of platelets in a specified quantity of whole
blood, usually a cubic millimeter, is a clinical procedure, the
result of which is of great diagnostic utility. A common method for
counting platelets employs dilution of a whole blood sample with
diluents which lyse or destroy the red cell component, permitting
microscopic enumeration of the remaining platelets. Electronic
particle counters, which have a substantially lower coefficient of
variation than visual counting methods have been employed in
platelet counting methodology, the coefficient of variation being
about 4 percent compared with about 16 percent for conventional
manual counting procedures. Further, less time is required for
performance of the enumeration.
Such electronic particle counting methods require prior separation
of whole blood into platelet rich plasma and a sediment consisting
of red and white blood cells. As commonly performed, the technique
requires sedimentation of a specimen of anticoagulated blood,
withdrawal of a specific quantity of the supernatant plasma, high
dilution in the region of 1:3000, followed by actual counting. The
processes employed in sedimentation of the whole blood sample
conventionally in common are time consuming, requiring at least ten
minutes and sometimes as long as thirty minutes per sample.
Further, filling the small bore plastic tubes ordinarily employed
to provide microliter samples, requires considerable manual
dexterity.
As reported by Brian S. Bull in American Journal of Clinical
Pathology, Volume 54, Number 5, November 1970, pages 707-710; it is
known to perform the separation of platelet rich plasma from whole
blood by augmentation of rouleaux formation followed by a period of
normal sedimentation. Rouleaux may be described as red cell
agglomerates or "stacks." One method employs anticoagulated blood
collected in a 10 .times. 75 mm test tube to be centrifuged at 40
times G for 25 seconds with the test tube held vertically so that
the amount of sample in the tube does not change the effective
rotation radius of the supernatant plasma. This short spin or
rotation produces rouleaux and is followed by a 1 to 2 minute
period of gravity or G sedimentation to produce a column of plasma
in which there is no layering of platelets.
A small table top centrifuge has been modified to permit this
procedure with the governor thereof adjusted so that the centrifuge
rotates at approximately 1,000 rpm.
Test tubes 12 .times. 75 mm are inserted into the head and fixed in
a vertical position so as to function as holders for the smaller
bore, 10 .times. 75 mm sample containing tubes.
Centrifugation at low gravity force is known as an alternative
method of specimen preparation involving the use of a large angle
head centrifuge for this purpose. Attempts to reproduce this
approach using a small centrifuge have not been successful. The
platelet rich plasma produced in the small angle head centrifuge
shows marked overall loss of platelets into the erythrocyte column
as well as layering of platelets immediately over the buffy coat.
This unequal distribution of platelets in the plasma column results
in platelet counts that vary from normal to as much as 40 percent
low depending on the height at which the plasma column is sampled.
Plasma prepared in a swinging bucket, tabletop centrifuge shows far
less layering and samples recovered from the upper third of the
plasma column provide counts that compare favorably with those in
plasma separated from the same blood sample by normal sedimentation
methods. Because the centrifugal force on the plasma column varies
appreciably with the amount of blood in the sample tube, great care
has to be exercised to provide identical amounts of blood in all
tubes. This requirement plus the possibility of taking the sample
at too great a depth from the plasma column makes the method
unsatisfactory as a routine clinical procedure.
It would be advantageous to provide a centrifuge apparatus which is
particularly adapted to the production of platelet rich plasma by
centrifugal augmentation of sedimentation. This requires a
relatively simple structure having timing means particularly
adapted for requirements of the desired method of centrifugal
augmentation, and which is reliable, repetitive and economical.
SUMMARY OF THE INVENTION
A centrifuge device for obtaining platelet rich plasma from whole
blood samples is provided comprising a centrifuge head and a motor,
the centrifuge head carrying multiple sample tubes in holders
arranged to orient the samples substantially parallel to the
rotational axis of the centrifuge head, the sample containers being
inclined inwardly toward the rotational axis of the centrifuge head
at an angle between 70.degree. and 90.degree. to the vertical so as
to render closure of the tube unnecessary. Transfer means are
connected between the motor and the centrifuge head for effecting
rotation of the same sufficient to exert greater than gravity force
laterally to the long axis of said sample containers. Means are
provided for effecting gradual slow down of the centrifuge head
after the motor has been deenergized. Timing means are provided
operable upon the motor and transfer means for operating the
centrifuge head in timed cycles. Alarm means also operated by said
timing means are provided for permitting ready ascertainment of the
completion and/or non-completion of the sedimentation process.
The timing means provided includes plural switch means, cam means
arranged to operate the plural switch means in a predetermined
cycle, means for stopping the driven rotation of the centrifuge
head substantially instantly with the deenergization of the motor,
and means for effecting the gradual slowdown of the centrifuge head
subsequent to deenergization of said motor.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the centrifuge device constructed
in accordance with the invention.
FIG. 2 is a partially exploded perspective view of the centrifuge
device illustrated in FIG. 1, the cover removed to show interior
construction.
FIG. 3 is a top plan view section taken along lines 3--3 of FIG.
2.
FIG. 4 is a sectional view of the centrifuge taken along lines 4--4
of FIG. 3 in the direction indicated.
FIG. 5 is a sectional view of the centrifuge taken along lines 5--5
of FIG. 3 in the direction indicated.
FIG. 6 is an enlarged detail of the spinner arrangement utilized in
the centrifuge of FIG. 1 illustrated in vertical sectional
representation.
FIG. 7 is a sectional view taken along lines 7--7 of FIG. 6, in the
direction indicated.
FIG. 8 is a fragmentary perspective view of the centrifuge head and
spinner arrangement illustrating the operation of the clutch means
provided in accordance with the invention.
FIG. 9 is a schematic representation of the electrical circuit
utilized to operate the centrifuge of FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The centrifuge apparatus provided by the invention for production
of platelet rich plasma from whole blood particularly is adapted
for the performance of a method for such plasma production which
capitalizes upon the fact that whole blood, if permitted to stand
in a vertically oriented container such as a test tube, will
separate into two layers. The upper layer comprises a layer of
platelet rich plasma containing some of the white cells present in
the original sample. The lower layer is a layer of red cells in
"stacked" formations known to the art as "rouleaux" which contain
the remainder of the white cells and a small amount of the plasma
of the original whole blood sample.
Three phases are known to occur during the sedimentation of whole
blood. The first is characterized as the "rouleaux" formation. This
phase occupies the first few minutes subsequent to filling the
container with sample. Following this first phase, the phase of
maximum sedimentation occurs, wherein after about three to five
minutes, the red cell rouleaux reach the maximum velocity of fall.
When whole blood enters this last mentioned phase, the separation
process and hence the production of platelet rich plasma per unit
time is optimal. If it is possible to augment rouleaux formation
and subsequently allow a period of sedimentation, then adequate
platelet rich plasma to permit platelet counting can be produced
rapidly. A method of rouleaux augmentation involves the application
of greater than gravity force laterally to a long thin container
vertically arranged and partially filled with whole blood.
According to the invention, there is a provided a centrifuge
capable of delivering a force in the range of 35 G. for a period of
less than one minute in duration in a lateral direction relative to
a long thin container which is only partially filled with whole
blood. The laterally applied force acts to pack the red cells into
rouleaux and to express from between the rouleaux a certain amount
of platelet rich plasma, the amount varying with the hematocrit of
the whole blood sample under test. Subsequent to the formation of
rouleaux, the centrifugal force is lessened gradually so that the
substantially vertical oriented layers of platelet rich plasma and
the red cells are permitted to slide down to the bottom of the test
tube where minimal mixing occurs, but without disruption of the
rouleaux. The centrifuge, in accordance with the invention,
provides for a period of rest so that normal sedimenation under 1
G. force is permitted, which in general will produce adequate
platelet rich plasma within a short length of time subsequent to
the augmentation of the rouleaux formation.
Generally, the red cell sedimentation has been accelerated by the
greater of the gravity force applied during the initial phases of
sedimentation in order to decrease the time required to form red
cell rouleaux. Subsequently, the blood sample is remixed gently to
obviate any inequality or layering of platelets within the plasma
layer and is permitted then to sediment. Since the blood is now in
a state where platelet rich plasma will be produced with a maximum
efficiency, a brief period sometimes less than two minutes is all
that is required to produce adequate platelet rich plasma for
counting purposes.
Referring now to the drawings, in FIG. 1 there is illustrated a
centrifuge device constructed in accordance with the invention and
generally designated by reference character 10. The centrifuge
device 10 includes a centrifuge head assembly 12 mounted for
rotation at high speed, housing 14 containing drive means for the
centrifuge head assembly, timer means and the other operating
components of the centrifuge 10.
The centrifuge head assembly includes a centrifuge head formed of a
pair of discs 16 and 18 coaxially mounted to a central shaft 20 in
spaced apart relation. A plurality of top opening cylindrical tube
holders 22 are secured to the lower disc 18 symmetrically about the
circumference thereof. Each tube holder 22 has a protrusion 24
axially depending from the bottom wall 26 thereof so as to be
received tightly in suitable openings 28 formed in the disc 18.
(FIG. 8) Each holder 22 includes an interior groove 30 in which an
O-ring gasket 32 is seated. The upper disc 16 has passageways 34
formed therein about the circumference thereof. Each of the
passageways 34 is arranged for alignment with a respective holder
22, with its center offset inwardly relative to the axis of the
matching holder 22. The openings 28 have a diameter sufficient to
accommodate loosely small test tubes 36 which are seated in the
tube holders 22, the O-ring gasket 32 engaging the tubes 36 close
to the bottom ends thereof. Tubes 36 are adapted to be partially
filled with anticoagulated whole blood sample.
When the discs 16 and 18 are assembled to the shaft 20, the
openings 28 are aligned with the open ends of the tube holders 22,
so that when the test tubes 36 are passed through openings 28 with
their closed bottom ends seated in tube holders 22, the vertical
axis of each of the tubes 36 is inclined at an angle of between
70.degree. - 90.degree. inward toward the rotational axis of the
centrifuge head assembly 12 so as to render closure of the sample
tubes unnecessary as will be described hereinafter.
The housing 14 is formed of a U-shaped cover 40 having a top panel
42 and a pair of opposite side panels 44. A front panel 46 is
provided with suitable openings 48,50,52 and 54 to provide for
passage of operating levers 56,58 and 60 and a window for a pilot
or indicating lamp 62. Lever 56 operates an on-off switch to
momentarily initially energize the timer means, lever 58 operates
an on-off switch to energize the buzzer circuit and lever 60
operates an on-off switch controlling the power to the centrifuge
device 10. The purpose of indicating lamp 62 shall be discussed
hereinafter.
Within the housing and secured thereto are a pair of platforms 64
and 66. Platform 64 includes an upstanding front wall 70 and
upstanding rear wall or panel 72. The upper platform 66 includes a
pair of right angle flanges or lugs 74 at the front corners thereof
and an upstanding rear flange 76. The platform 66 is secured to the
front wall 70 by suitable fastening means such as screws 78. The
platform 66 has a rear extension 80 arranged to be fastened by
suitable bolt means 82 to the right angle inwardly extending lug 84
at the upper edge of rear panel 72. The upper platform 66 also
referred to as an upper chassis 66 carries on the top surface
thereof, the timing means and primary switch means associated
therewith, as well as means for transferring rotary motion from the
motor to the centrifuge head assembly 12. The motors operating the
drive and the timing means respectively are secured to the
undersurface of the platform 66 by suitable fastening means such as
including nut and bolt means 86 and nut and bolt means 86'. The
lower chassis or platform 64 has mounted thereto, the master switch
means 88 and alarm means, here in the form of buzzer means 90. The
electrical connection to the line is made at socket 92 which is
mounted to the rear panel 72 of lower chassis 64 while the
operating on-off switches are arranged mounted to the front wall of
chassis 64. A notch 94 is provided opening to one edge of the
platform 66 to permit passage of necessary electrical leads between
the platforms 66 and 64.
The drive means for centrifuge device 10 comprises a d.c. drive
motor 96 which has a driven shaft 98. Driven shaft 98 carries drive
pulley 100 having circumferential groove 102. A support bracket 104
is mounted to the platform 66. The bracket 104 includes a
horizontally disposed flange 106, the flange having a passage 108
to accommodate driven shaft 112 therethrough. Driven pulley wheel
114 is mounted on shaft 112 between the flange 106 and the platform
66 and includes a depending conical bearing 116 coaxially arranged
on the undersurface thereof, and a mounting center post 118.
Cylindrical tubular collar 120 is secured to bracket flange 106
through passage 108 with integral flange 122 thereof seated upon
the undersurface of said flange 106. Collar 120 functions as
journal means for the shaft 112. The driven pulley wheel 114
carries circumferential groove 115 which is aligned horizontally
with groove 102 of pulley 100. An endless belt 124 drivingly links
the drive pulley 100 with the driven pulley 114 by virtue of
seating within grooves 102 and 115.
The timer means provided by the invention for operating the
centrifuge device 10 in accordance with a predetermined timed
cycle, comprises a cam member 126, a timer motor 128, including
gear reduction means 130, contact switches 132, 134 and 136
operating master switch means 88 and the buzzer means 90.
Contact switch 132 includes contact arm 138 having a rolling
contact member 140 engaged on the outer circumferential edge of the
central circular cam 142 of cam member 126. Contact switch 132
normally is closed and controls the operation of the drive motor
96. Circular cam 142 has a notch 143, including drop-off 145 and
inclined surface 147.
Contact switch 134 functions as the timer motor control and
includes a switch arm 144 having a roller contact in engagement
with one corner 148 of the lower cam block 150 of cam 126. Closure
of switch 134 deenergizes the timer motor 128.
Switch 136 controls the operation of the buzzer means 90. Switch
136 includes a switch arm 152 having a roller 154 disposed in the
path of corner 156 of the upper cam block 158 of cam member 126.
Block 158 is of generally rectangular configuration, but has a
diagonal side surface 160, one corner 156 of which is arranged to
intercept the roller 154 causing the switch arm 152 to close switch
136. Closure of the switch 136 energizes the buzzer means 90.
According to the invention, spinner means 162 are provided to mount
the driven shaft 112 to the centrifuge head assembly. Spinner means
162 comprises a cylindrical hub 164 having an axial bore 166 of
diameter selected to enable telescopic engagement, frictionally,
with the driven shaft 112, suitable means such as Allen nuts being
utilized to maintain the assembly and yet permit selective
disengagement when desired. A pair of spaced like circular discs
168 and 170 are arranged coaxially at one end of the hub 164, flush
with one end of said hub 164. A pair each of pins 172 and 174 are
fastened between the discs 168 and 170. Pins 172 are disposed
diametrically opposite each other along a line taken through the
rotational axis of hub 164. Pins 174 likewise are disposed
diametrically opposite one another along a line also intersecting
the axis of said hub 164. In this manner a pin 172 is associated
with a pin 174 in pairs on opposite sides of the hub 164, each of
said pins 172 and 174 being spaced inwardly of the circumferential
edges of the matched discs 168 and 170.
Band springs 176 each having a loop 178 at one end thereof are
journalled for free rotation on pins 172 and between the hub 164
and the pins 174. The springs 176 accordingly can move between the
shaft 164 and the pins 174 so that the free ends 180 are movable to
a position outwardly extending from the circumferential edge of the
spinner discs 168 and 170 and each bearing at its approximate
midportion against a respective pin 174. On rotation of the spinner
means 162 in the direction of the arrow 182, the springs 176 are
forced outward from the spinner 162 to their broken line position
shown in FIG. 7.
The lower disc 18 carries a pair of diametrically spaced depending
pins 184, which are arranged so as to intercept and engage the
springs 176 when the springs 176 are in their outwardly extending
or broken line position on initiation of rotation of the spinner
means 162 whereby to drive the centrifuge head assembly. The lower
disc 18 of the centrifuge head 12 also carries an axial socket 186
opening downwardly. Ball bearing assembly 188 is mounted tightly
within said socket 186 which assembly 188 includes a central
passage 190 capable of receiving the hub 164 of spinner means 162
so that the centrifuge head 12 is rotatable freely on hub 164 of
the spinner means 162.
As earlier stated, spinner means 162 is fastened securely to the
driven shaft 112 and rotates therewith. On rotation of the spinner
means 162, in the direction of arrow 182 the springs 176 are
directed outwardly of hub 164 by centrifugal force so as to
intercept the depending pins 184, driving the centrifuge head
assembly 12. When the rotation of the driven shaft 112 is stopped,
rotation of spinner means 162 ceases. However, the rotation of the
centrifuge head assembly 12 does not stop, since it is freely
rotatable on hub 164 by virtue of bearing means 186. The pins 184
simply continue to rotate engaging the springs 176 and causing same
to be driven inward toward the hub 164. The centrifuge head
assembly therefore is permitted gradually to slow down until it is
at rest.
In operation of the centrifuge apparatus 10 in accordance with the
desired method, the blood samples are introduced into the test
tubes 36 partially to fill same. The tubes then are deposited each
in a respective one of openings 34 to seat in respective holders
22. Because the openings 34 are off-set inwardly of the axis of
rotation of head assembly 12 as compared with the position of the
matching holder 22, the test tubes are inclined with their upper
ends inwardly directed toward the axis of rotation of the
centrifuge head assembly 12, closure of the upper ends of the tubes
36 is not required and spillage will not occur. The centrifuge head
assembly is rotated to apply about 35 G force laterally to the long
axis of tubes 36. The time period duration for application of such
high G force is less than one minute, preferably from 10 to 15
seconds. As will be seen in the foregoing table, the total elapsed
time of the procedure is about 300 seconds.
The operation of the centrifuge apparatus 10 now will be described
with reference to the foregoing table and the circuitry illustrated
in FIG. 9.
______________________________________ TIME 0-5 5-35 35-295 295-299
300 SWITCH SECS. SECS. SECS. SECS. SECS.
______________________________________ 136 OPEN OPEN OPEN CLOSED
OPEN 134 CLOSED OPEN OPEN OPEN CLOSED 132 CLOSED OPEN CLOSED CLOSED
CLOSED 206 CLOSED OPEN OPEN OPEN OPEN 204 CLOSED OPEN OPEN OPEN
OPEN ______________________________________
After the partially filled test tubes 36 have been introduced into
the head 12 the power lever 60 and the buzzer lever 58 are
depressed closing switches 200 and 202 respectively. The start
lever 56 then is depressed momentarily closing switch 204,
energizing the timer motor 128 causing the cam 126 to rotate in the
direction of the arrow 127. With the momentary closure of switch
204, the spinner drive motor 96 is energized by closure of normally
open switch 206. The energization of spinner motor 96 causes the
drive pulley 100 to rotate, said rotation being transmitted
simultaneously by belt 124 to the driven pulley 114, driving the
spinner shaft 112 to rotate the spinner means 162. Rotation of the
spinner means 162 directs the springs 176 outwardly intercepting
the posts 184 of the centrifuge head assembly 12 causing same to
rotate.
In the meantime, rotation of the cam 126 causes the switch 132 to
be open by the dropping of roller 140 from the circumferential edge
of the circular cam 142 at drop-off 145. Opening of switch 132
continues the spinner motor operation until the cam member 126 has
rotated sufficiently so that the roller 140 of spring arm 138 has
moved along inclined surface 147 to place the circumferential edge
142 in contact with the roller 140 of spring arm 138, closing
switch 132 and deenergizing the spinner motor 96.
When the spinner motor 96 is deenergized, the pulley 100 ceases its
rotation and, because of the linkage by belt 124, the cessation is
transmitted immediately to driven pulley 114 so that rotation of
the spinner means 162 ceases. However, the centrifuge head assembly
12 continues to rotate freely at a gradually diminishing rate until
rotation ceases.
In the meantime, the cam member 126 continues to rotate. After an
elapsed time required for the centrifuge head assembly 12 gradually
to come to rest, the corner 156 of cam block 158 intercepts the
buzzer switch 136 to close same causing the buzzer to operate for a
short period of time. Now the operator is alerted to the fact that
the natural sedimentation stage is soon to be completed. After a
short time lapse, one corner of block 150 intercepts the roller 146
of switch arm 144 closing switch 134, thereby deenergizing the
timer motor 128 and, at the same time, corner 156 passes roller 154
to release arm 152 opening switch 136 to deenergize the buzzer
means 90. The natural sedimentation has been completed at this time
and the test tubes 36 may be removed and the supernatant platelet
rich plasma siphoned or otherwise removed by conventional
means.
The centrifugation can be varied simply by varying the length of
the inclined surface 147 of notch 143 in the circular cam 142. The
duration of the gradual slow down and rest period required to
assure sufficient time for natural sedimentation to follow the
period of augmentation of rouleaux formation can be varied simply
by varying the circumference of said portion 142 and the location
and dimensions of cam block 150. The timing is controlled by the
cam member 126 with the cams 142, 150 and 158 operating upon their
respective switches 132, 134 and 136 as described. The transmission
of driven rotation from the spinner to the centrifuge head assembly
12 is accomplished by means of the springs 176 engaging the posts
184, so long as the spinner means 162 rotates. When rotation ceases
the springs are forced out of their driving intercepting condition
by continued rotation of the centrifuge head assembly freely.
The pins 174 limit outward movement of the springs 176 and, also
function to provide a stop against which the springs 176 can bear
so that when the pins 176 engage the posts 184, the posts are
driven with the rotation of the spinner means 162. The use of a
pair of springs 176 permits balancing of the loads placed upon
springs 176 and reduces the shock produced by the engagement of the
springs 176 with the posts or pins 184 on initiation of rotation of
said spinner means 162.
Indicator lamp 62 is provided connected across the timer motor 128
and is energized so long as said timer motor is energized. While
the indicator lamp 62 is energized, the sedimentation process is
incomplete. When extinguished at the terminus of the cycle by
operation of switch 134, settling has been completed, the tubes 38
removed and the platelet rich plasma decanted.
As can be noted from the description hereinabove, the centrifuge
device 10 is a relatively economical assembly of readily available
components with equally economic timing means provided. The
assembly is compact and highly suitable for the production of a
platelet rich plasma fraction from whole blood samples in
accordance with the desired method of augmenting rouleaux formation
at its inception by centrifugation, that is the application of high
G force laterally to vertically arranged columns of the whole blood
sample. The test tubes 36 which hold the sample are passed through
openings 34 and seated in holders 22. On the driven rotation of the
centrifuge head assembly and for a considerable duration of the
free rotation of said head assembly, the plasma and red cell layers
will be held against the outwardly facing inner wall of the
respective test tube 36 is a desired vertically oriented
arrangement except for their inclination at angles between
70.degree. and 90.degree. from vertical, directed inwardly, their
upper ends pointing toward the rotational axis of the centrifuge
head assembly 12 so that spillage is avoided.
It is feasible to utilize holders 22 and openings 34 of diametric
dimensions sufficient to receive test tubes of slightly larger
diameter than tubes 36. Thus, tubes 12 .times. 75 mm may be set on
the head 12 while the tubes 36, being 10 .times. 75 mm may be
seated within the larger tubes. Also, it is likewise feasible to
construct the shaft 20 so that the disc 16 is seated thereon closer
to disc 18. In such instance, the openings 34 are spaced closer to
the circumferential edge of the disc 16 so as to maintain the
desired inclination of the tubes 36 at the lower position of disc
16 relative to disc 18. In the lower position, an effective guage
or measure thus is provided to aid the operator in visibly
determining and maintaining the level to which the tubes 36 can be
filled without exceeding the level which could result in spillage
during centrifugation, notwithstanding the angle of
inclination.
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