Note: Descriptions are shown in the official language in which they were submitted.
~ - ~ogz~99 ~IP-6880/6881
Backqround of the Inventton
Fieid of the Invent70n
This invention relates to the field of biological testing a
bacterial suspension against a variety of reagents simultaneously.
The invention relates to the field of test apparatus which contains a
plurality of chambers for conducting different tests upon a common test
specimen. More particulariy the invention relates to the prevention
of the release of gas, vapor, or liquid from the test apparatus during
use thereof.
Descri~tion of the Prior Art
In the past a variety of different methods has been employed for
the identification of organisms in families of bacteria such as
Neisseria and Enterobacteriaceae. Many of these methods have relied
upon the different patterns of development of cultures in the presence
of a variety of fermentation media. One of the most common species of
Neisseria is N. qonorrhoeae.
; Until recent years the identification of N. qonorrhoeae although
accurate required a twelve to sixteen hour incubation period.
It is now possible, however, through the use of a rapid fermentation
process described by D.S. Kellogg and E.M. Turner, in an article
entitled "Rapid Fermentation Confirmation of Neisseria Gonorrhoeae"
published in Applied Microbiology, April 1973, p. 550-552, to decrease
the incubation time to about four hours. This method as in the past
utilizes the different growth patterns of the organisms in a variety of
fermentation media but is able to speed up the fermentation process
through the use of a lightly buffered salt solution. The basic method
of patterned growth identification, however, is relatively the same.
For example, N. Gonhorrhoeae will ferment glucose wh7le being
completely unreactive to maltose, fructose, sucrose, lactose and mannitol.
AH~-6880/6881
~O9Z~99
Table I whtch Is taken from the Kellogg-Turner artlcle Is a
complete list of the species within the Ne7sseria genus, which
includes N. Gonorrhoeae, showing their individual patterns against
the six most common fermentation media used in their identiflcation.
TABLE l: Typical Growth Fermentation Reactions of
Neisseria Species
Glu- Mal- Fruc- Su- Lac- Manni-
Organism cose tose tose _crosse tose tol
.
N. gonorrhoeae +
N. meningitidis + + - - --
N. Iactamicus + + - - +
N. subflava + + - - - -
N. flava + + +
N. perflava + + + +
N. sicca + + + +
N. flavescens
N. catarrhalis
W. J. Brown Tn his paper published in Applied Microbiology,
June 1974, p. 1027-1030, developed an improved method of rapid0
fermentation of Neisseria qonorrhoeae based on the Kellogg-Turner
method mentioned above. Brown by varying the volumes of buffer-salt
solutions used by Kellogg and Turner in their testing procedure was
able to reduce the time necessary to obtain positlve results from
approximately four to two hours.
Enterobacteriaceae is a class of bacteria found in animals
wherein many of the species within a genus can be identified by its
growth pattern in a variety of fermentation media. Table 2 lists the
typical biochemical reactions of Enterobacteriaceae against the ten
most common fermentation media used in their identlfication.
A~IP-6880/6881
``'` lO9Z499
+ test result generally positlve
+ test result more often positive
- test result generally negative
+ test resuIt more often negative
d iilfferent biochemical types
Although the above-mentioned methods have resolved most of the
objections as to time of incubation and accuracy of results they still
require a human operator to first prepare the fermentation media and
- place them in a series of test tubes or containers and then individually
inoculate these tubes with the bacterial suspension to be tested.
This preparation process is not only time consuming, but also has the
disadvantage of exposing the operator to the bacterial suspension while
inoculating the tubes. In some cases such as in testing of Enterobacteriaceae
there can be as many as twenty tubes to be prepared and inoculated.
Thus it can be seen that the amount of handling and time required to
complete the inoculation can become quite substantial. Another difficulty
is that the tubes or containers must be suitable to be subjected to a
water bath for accelerating the rate of reaction.
U.S. Patent No. 3,832J532 which issued on August 27, 1974, in
addition to disclosing a photometric apparatus and an incubator shaker
device, discloses a compartmented contalner for testlng an Inoculated broth
against a variety of antibiotics. This device consists of a plurality
of linear arranged curvettes attached and in communicatjon with an end
reservoir. Initially the end reservoir is filled
-4-
~P-6880/6881
~O9Z~99
LL
~ ~ J ~ v~
ZIIJ O O O O u) LIJ O
-- ~ ~ ~ ~ ~ z O _
z o ~ m ~ ~ o
~ ~Z J o tY
(.)--'1: ~ Z O I
1 23 4 5 6 7 8 9 lO
_ _
E. coli - + + d - + d d
Shigella - + d d - d d - d
_
Citrobacter - + + d - + + _ d d
_
Arizona - + + ~ ~ + + ~ ~ +
Salmonella - + + d d + +
K. pneumoniae + + + + + + + + + +
E. aerogenes + + + - + + + + +
. _
E. cloacae + + + + _ + + + + +
-
E. hafniae d + + - - - + -
- E. Iique- + + + - + + _ +
faciens
Serratia + + + - + + - +
_
Proteus _ + _ _ - - d +
vulgaris
P. mirabilis d + - - - - - +
P. morganii - + - - - - - d
P. rettgeri - + + - + - d d
: 20
Providencia
dlcalifaciens + d - - _ _ d
Providencia + d - + d - d
stuarti i
Ed~ardsiella + - - - - - - -
. _
~ith the broth to be tested and then, through a three step physical
manipulation of the entire apparatus, the inoculated broth i5
delivered to the plurality of curvettes and thus contacts the
individual antibiotic discs located at the bottom of the curvettes.
--5--
~IP-6880/6881
~" ~092499
U.S. Patent No. 3,676,377 which issued on April 8, 1975
discloses a plurality of transparent micro-receptacles mounted on a
thin support each of which is provided with a dosed quantity of
determined coloured reagents. The products to be analysed is introduced
into each receptacle in liquid form and the reaction or non-reaction
is observed.
Unlike the present testing device inoculation of the above-
mentToned micro-receptacles must be done individually. Also these
micro-receptacles cannot be sealed once the product to be analysed is
introduced; thus heating in a water bath to speed up the fermentation
process would be difficult.
SummarY of the Invention
Now it has been found that the above disadvantages may be overcome
by providing a bTological testing device which consists of a hollow base
container and associated plug. The plug is designed to fit snugly within
the base container. The base container is provided at its closed end
with a plurality of microtubes arranged around the inside periphery of
the container, thereby forming a central chamber in the lower portion
of the base container. These microtubes are open at the top and are
vented to the central chamber. The closed end of each microtube is
provided with a dehydrated chemical reagent material for testing a bacterial
suspension. Prior to the use of the device, the plug is removed from
the container, thus exposing the central chamber and surrounding
microtubes located at the bottom of the container. The bacterial
suspension to be tested is then disposed in the central chamber.
-6-
AHP-6880/6881
109Z499
Thereafter the plug is partially inserted into the container and
the -lotal device is inverted. While the device remains in its
inverted position, the plug is urged inwardly with respect to the
container until it is fully inserted into the container. The plug is
provided with a vent passage extending therethrough to prevent the creation
of an excessive or undesirable pressure condition within the container
when the plug is urged thereinto. At this time the entire device is
reinverted, thereby distributing substantially equal amounts of
bacterial suspension to each of the microtubes.
The invention comprises a compression compensator assembly
which consists of a chamber adapted to cover the vent passage or
aperture of the btological testing device in order to prevent gas,
vapor or liquid from being vented from the testing device into the
surrounding atmosphere. The chamber of the compensator contains a
movable piston-like disc which enables the volume of the chamber in
communication with the vent passage to be varied. Thus the portion of
the chamber adjacent the vent passage is sealed from the atmosphere while
the remaining portion of the chamber is adapted to be vented to the
atmosphere.
Prior to the use of the compensator with the test apparatus,
the disc is placed in its initial position within the chamber which
is to be adjacent vent passage. The compression compensator is then
attached to the portion of the biologica! testing device having the vent
passage. Thereafter the biological testing procedure is carried out.
During use of the testing apparatus, gas or vapor within the testing device
may become contaminated by the bacterial suspension being tested.
When such gas or vapor is expelled from the testing device, it is
introduced into the portion of the chamber of the compression compensator
A~iP-6880/6881
` 1()9Z499
between the connection to the vent passage and the disc. The introduction
of such gas of vapor results tn an increase of pressure within the lower
chamber causing the disc to be moved along the chamber in the manner of
a piston. As the disc moves, it increases the volume of the chamber into
which the expelled gas or vapor can be stored. The volume of the other
portion of the chamber is proportionately decreased by the movement of the
disc and the excess air from the other portion is vented to the
atmosphere.
Accordingly an object of the present invention 7s to prevent the
escape of possibly contaminated fluid from the interior of a biological
test7ng device during its use.
Another object of this invention is to prov7de a chamber to
receive and hold any flu7d which may be vented from the intertor of a
biological testing dev7ce during use.
A further object of the Invention is to provide a chamber
which can be fitted to a biological testing device adjacent the
venting provision thereof to receive and hold any fluid vented from the
testing device.
Still another object of the invention is to prevent the
possible escape into the atmosphere of a bacterial aerosol from the
interior of a biological testing device.
Another object of this invention is to provide a test7ng
device wh7ch will be ready to use and which will reduce the time
required in carrying out a plurality of tests upon a single bacterial
suspension.
A further object of the 7nvention is to provide a testing
aevice which is adapted to be heated 7n a warm water bath to speed up
the testing of the bacteria against a number of reagents.
~ogz~99 AI~P-6880/6881
In one aspect of this invention, there is provided a
biological testing device comprising: a tubular container having
an opening in its upper portion extending across the longitudinal
axis of the tubular container, the lower portion of the tubular con-
tainer being closed, structure forming a plurality of tubes disposed
adjacent the inside periphery of the lower portion of the container,
each tube having its length extending substantially parallel to the
longitudinal axis of the container and having an open end portion
facing the opening in the upper portion of the container and a closed
end portion disposed opposite thereto, the tubes and the closed end
portion of the container forming a central open chamber therewithin
facing and substantially in alignment with the opening in the container,
the chamber being adapted to hold a biological test suspension; and
a plug for closing the upper portion of the container, the
plug having a cap portion and a neck portion narrower than the cap
portion and adjacent thereto, the cap and neck portions forming a
shoulder therebetween, the cap portion of the plug being adapted to
fit slidingly and removably within the upper portion of the container
to substantially seal the container, the plug having an initial position
~: 20 with respect to the container in which the cap portion of the plug is
engaged with the upper portion of the container and the shoulder portion
of the plug is spaced from the open end of each of the plurality of
tubes, the plug in the initial position thereof enabling the test sus-
pension to pass from the central open chamber to the shoulder of the plug
when the testing device is inverted, the neck portion of the plug being
adapted to fit slidingly and removably within the central open chamber
and to substantially seal said chamber when the plug is fully inserted
into the container, the plug having a~final position with respect to the
container in which the cap portion of the plug is further within the upper
portion of the container, the neck portion of the plug engages and sub-
-8a-
~ ~ 9 2 ~ 9 ~ P-6880/6881
stantially seals the open central chamber and the shoulder portion of
the plug is adjacent the open end of each of the plurality of tubes and
substantially divides the test specimen in an approximately equal amount
with respect to each of the tubes, the divided test specimen being con-
fined within the individual tubes as the testing device is reinverted.
In another aspect of this invention, there is provided a bio-
logical testing device comprising: a transparent cylindrical container
having an opening in its upper portion extending across the longitudinal
axis of the container, the lower portion of the container being closed,
structure forming a plurality of tubes disposed adjacent the inside
periphery of the lower portion of the container, each tube having its
; length extending substantially parallel to the longitudinal axis of the
container and having an open end portion facing the opening in the upper
portion of the container and a closed end portion disposed opposite
thereto, the tubes and the closed end portion of the container forming
a central open chamber therewithin facing and substantially in alignment
with the opening in the container, the chamber being adapted to hold a
biological test suspension, a portion of each tube of the plurality of
tubes adjacent the open end portion thereof and facing the central chamber
has an aperture for venting the tube to the central chamber, said tubes
also being provied at the closed end thereof with a predetermined chemical
reagent material; and
: a plug for closing the upper portion of the container, the
plug having a cap portion and a neck portion narrower than the cap
portion and adjacent thereto, the cap and neck portions forming a shoulder
therebetween, the cap portion of the plug being adapted to fit slidingly and
removably within the upper portion of the container to substantially seal
the container, the cap portion of the plug having a first and second
seating grooves in the surface thereof adapted to engage a retaining ridge
positioned in the inner surface of the upper portion of the container
for holding the plug at an initial and final position with respect to-the
container, wherein in the initial position the cap portion of the plug is
-8b-
~09Z~99
AIIP-6880/6881
engaged with the upper portion of the container and the shoulder portion
of the plug is spaced from the open end of each of the plurality of
tubes, thus enabling the test suspension to pass from the central open
chamber to the shoulder of the plug when the testing device is inverted,
the neck portion of the plug being adapted to fit slidingly and
removably within the central open chamber to substantially seal said
chamber when the plug is fully inserted into the container, the end of the
neck portion of the plug opposite the shoulder portion of the plug being
tapered, wherein in the final position the cap portion of plug is further
within the upper portion of the container, the neck portion of the plug
is within the central chamber and the shoulder portion of the plug is
adjacent the open end of each of the plurality of tubes dividing the test
specimen substantially into equal amounts with respect to each of the
tubes, the divlded test specimen being confined within the individual
tubes as the testing device is reinverted, the plug also being provided
with a passage extending through the length of the plug from the cap
portion to the neck portion thereof, the passage venting the interior
of the central chamber of the container when the plug is inserted into
the container.
-8c-
1092~99 AHP-6880/6881
Still another object of the invention is to provide a
testing apyaratus which is adapted to divide a bacterial suspension
simultaneously into substantially equal aliquots to be tested against
a variety of reagents.
Brief Description of the Drawings
For a fuller understanding of the invention reference is had
to the following description taken in connection with the accompanying
drawings of the preferred embodiment in which:
FIG. 1 is a perspective view of the biological testing device
showing the plug removed from the container;
FIG.2 is a plan view of the testing device;
FIG. 3 is a vertical section view of the container with the
plug removed and showing a bacterial suspension disposed in its lower
central chamber;
FIG. 4 is a vertical section view of the container with the
plug inserted to its initial position;
FIG. 5 is a vertical section of the container inverted while
the plug is Inserted to its intial position and the bacterial
suspension is resting on the shoulder of the plug;
FIG. 6 is a cross-sectional view of the apparatus showing
the plug fully inserted to its final position and the shoulder of
the plug contacting the opening of the microtubes;
FIG. 7 is a cross-sectional view bf the apparatus right-
side up showing the plug inserted to its final position and the
suspension to be tested contracting the reagent media at the bottom
of the microtubes;
FIG. 8 is a vertical section view of an embodiment of the
apparatus in which the plug is provided with a skirt portion to contain
the suspension being tested;
FIG. 9 is a perspective view of the apparatus showing indicia on
the outer surface thereof;
A~IP-6880/6881
109Z~99
FIG. 10 is a fragmentary vertical sect70n vlew show7ng the
container provided with a compresslon compensator with the separation
disc thereof in its initial position;
FIG. Il is a vertical section view of the compression compensator
mounted in its operative position; and
FIG. 12 is a fragmentary vertical section vTew of a seal
construction for the separation disc of the compression compensator.
Descri~tion of the Preferred Embodiments
As shown in the drawings the biological testing device of the
present invention comprises essentially two parts intended to work in
conjunction with each other to distribute a substantially equal amount
of bacterial suspension simultaneously to a number of different
reagents.
Referring now more particularly to the accompanying drawings
wherein like numerals designate slmilar parts throughout the various views,
attention is directed first to FIG. 1, wherein the biological testing
apparatus 10 of the present invention comprises a hollow base container
20 hereinafter referred to as a container and a plug 30. By way of
example, the container and plug can each have an outside diameter less
than one inch. Arranged around the inside wall of the lower portion of
the container and extending vertically approximately half-way up the
inner wall 21 is a plurality of microtubes 22. These microtubes are open
at the top and are provided with venting aper-tures 23. These microtubes as
shown in FIG. 3 are also provided at the bottom with different dehydrated
reagents 24 for testing a bacterial suspension 26. As shown in FIG. 2
the arrangement of the microtubes 22 around the inside wall 21 of the
container, provides for the formation of a central chamber 25 at the
lower half of the container 20. This central chamber is adapted to
--10--
~092~99 AHp~6880/6881
hold the bacterlal suspenslon to be tested. These mlcrotubes can
comprlse a plurality of separate tubes, or may be integrally formed or
molded as part of the base container.
Referring again to FIG. 1, the upper portion of the container
is provided with a ridge 21a which can be molded or formed to the
; inside wall 21 of the container 20. The ridge is adapted to engage
and sent within the groove 31 or groove 32 located on plug 30 when the
plug is inserted into the container. The ridge and grooves make it
possible to lock the plug in an initial position when ridge 21a is seated
in groove 31 and a final position when ridge 21a is seated in groove 32.
Alternately the grooves 31 and 32 may be located on the inslde wall 21
of the container 20 and the ridge 21a may be located on the plug 30.
As can be seen from FIG. 1, plug 30 is composed of an upper cap
portion 30a and a lower neck portion 30b. The neck portion is adapted to
fit slidingly and removably into the central chamber 25 located within the
lower portion of the container 20. The upper portion of the plug 30 is
adapted to fit slldingly and removably into the upper portion of the
container 20. Since the cap and neck portion of the plug are of different
sizes, a shoulder 33 is provided where the cap portion of the plug joins
the neck portion of the plug. The shoulder 33 contacts and seals the
opening of the microtubes 22 when the plug 7s fully inserted into the
container. It should be noted that the plug 30 and container 20 are
designed such that when the plug is inserted into the container, the
upper portion 30a of the plug forms a substantially ai`r tight seal
with the upper portion of the container 20, thus preventing the passage
of liquid and air to the exterior of the apparatus.
.~
; 30
'
_ I I _
~IP-6880/6881
1[)~2499
Furthermore when the plug is fully inserted into the
container, the outside surface of the lower portion 30b of the plug
contacts the inside surface of the central chamber 25 located in the
lower portion of the container, it also forms a substantially air tight
seal between the central chamber and the rest of the container, the plug
prevents the passage of liquid from the upper portion of the container
to the central chamber.
Plug 30, when inserted into the container, forms a substantially
air-tight seal with the container, thereby preventing escape of air from
the interior of the device which results in the formation of an internal
pressure within the central chamber and surrounding microtubes. This
can cause resistance to the insertion of the plug fully into the container.
Such resistance due to pressure can be reduced by a system of venting
apertures and passages Which connect the interior of the container and
microtubes to the outside atmosphere in the following manner. Referring
to FIG. 1, each microtube 22 is provided at its open end with a venting
aperture 23 which vents the interior of the tubes to the central chamber.
The central chamber 25 is in turn vented to the exterior of the apparatus
by means of a passageway 34 extending vertically through the plug.
This passage is of a size to prevent the passage of solution to the
exterior of the device and yet allow the escape of air from the internal
chambers of the container so that full insertion of the plug into the
container is possible. By way of example, passageway 34 may comprise a
fine bore hole such as that produced by a #80 drill. Although the
passageway 34 greatly reduces the pressure within the central chamber and
surrounding microtubes, thereby allowing the plug 30 to be easily
inserted, it should be understood that this passageway is optional and
that the apparatus will function properly without it.
-12-
~IIP-6880/6881
1092499
Prlor to the use of thls devlce, plug 30 is removed from
the container 20, thereby exposing the interior of the central chamber
25 located at the bottom of the container as shown in FIG. 2.
The bacterial suspension 26 to be tested, in liquid form, is then
disposed in the bottom of the central chamber 25.
Immediately thereafter the plug is partially inserted into
the container until the initial seating groove 31 loc~ted on the plug 30
engages the retatning ridge 21a positioned on the inside wall 21 of the
upper portion of the container as shown in FIG. 4, thereby locking the
plug in its initial position. In this initial position, the upper portion
of the container 20 is sealed by the upper portion 30a of the plug 30; however,
the lower or neck portion 30b of the plug 30 has not yet contacted the
inner walls of the central chamber 25 nor has the shoulder of the plug
contacted and sealed the opening of the microtubes 22. As can be
seen from FIG. 4, when the plug is in its initial position the central
chamber 25 has not yet been sealed to the space wh7ch exists between the
shoulder 33 of tne plug and the top of the microtubes.
The entire testing device is then fully inverted as shown in
FIG. 5 while the plug is stlll in its initial position relative to the
container. This causes the bacterial suspension 24 to travel down along
the cone-shaped tip of the neck portion of the plug as shown by arrows in
FIG. 5 and come to rest on the shoulder 33 of the plug. The cone-shaped
tip of the neck portion of the plug depicted in the preferred embodiment
serves a two-fold purpose. One is to insure that no liquid is trapped
in the central chamber 25 when the plug is fully inserted into the
container as would be possible if the end of plug 30 were flat.
Secondly the cone-shaped tip helps divert the suspension 26 away from
the venting passage 34, leaving it unobstructed to vent the interior of
the container of air. As mentioned above, upon inverston of the device
bacterial suspension 26, has come to rest on shoulder 33. Since the
A~iP-6880/6881
1092~99
suspension is in liquid form it will seek Tts own level and distribute
itself evenly around the plug. Thls even distribution will play an
important part in determining the subsequent division of the suspension
into equal aliquots to be delivered to the microtubes.
While the device is still in the inverted position the
plug is urged further into its final position so that as shown in-
FIG. 6 the final se~ting groove 32 engages the retaining ridge 21a
on the inside wall of the upper portion of the container. In this
position the neck portion 30b of the plug 30 comes into communication
with the inside wall of the central chamber 25 sealing it with respect
to the bacterial suspension 25 which is still resting on shoulder 33 of
the plug. At the same time the top openings of the microtubes 22 are
brought into communication with shoulder 33 of the plug whereupon the
suspension 26 which has been resting on the shoulder is divided into
equal aliquots by the upper open portion of the microtubes ?2. The
entire assembly is then reinverted as shown in FIG. 7. The liquid
suspension 26 which has been evenly divided by the upper open ends of
the microtubes 22~now descends into the tubes 22 and come into contact
with dehydrated reagents 24 located at the closed end of the microtubes 22.
Thereafter the bacterial suspension may or may not react-with the
individual reagents and thereby perform the required test procedure.
During construction of the apparatus the inner surface of the closed
end porttons of the microtubes are textured or roughened to facilitate
the adhesioll of the chemical test reagent to the closed end portion of
the microtubes.
If it is desired to speed up the test reaction the entire
apparatus may be placed in a warm water bath. As shown in FIG. 9 the
apparatus is designed such that tn the closed condit!on the microtubes
are sealed both from each other and from the exterior thus the operator
does not have to be concerned about keeping the apparatus in an
upright position.
-14-
` 1~92499 A~IP-6880/6881
Although the contatner and plug of the present Invention
may be constructed of a variety of different materials, one should
keep in mind when selecting the material to be used the type of
bacterial suspenston and the reagents which are to be used tn conjunctton
with the apparatus, stnce any reactton between the contatner and its
contents must be avoided.
The use of transparent plastic resin such as polystyrene is
conventent for the constructton of the container slnce tt is not only
chemically inert to the bacterta and reagents but also has the added
advantage of betng transparent and eastly molded. The transparency
enables the operator to clearly view at a glance the reactton or non-
reaction taktng place wtthtn the mtcrotubes. If the container is
constructed of a non-transparent matertal, it should be provided with
vtewing windows or a transparent strip which would run around the
circumference of the container, making observation of the interior of
the microtubes possible. The plug can be constructed from a variety of
~; different resilient-type materials such as styrene which would improve
the sealing capabtltttes of the plug wtth the contalner.
As mentioned tn the foregotng dtsclosure when the plug is
inserted into the container it forms a number of substantially air tight
seals. The qualtty of these seals may be tncreased, if desired, by
a number of rubber sealtng rings, whtch can be located on the outer
cTrcumference of the plug. The first is located on the cap portion
of the plug to increase the quality of the seals between the plug and
the upper portton of the container. The second is located on the neck
portton of the plug to tncrease the seal between the neck portton of
the plug and the centra1 chamber of the container, when the plug is in
its final position. The third is located on the shoulder 33 of the plug,
.
AilP-6880/6881
lO~?Z499
to increase the quality of the seal between the upper open portion of the
microtubes and the remainder of the container, when the plug is in its
final position.
Another embodiment of the present invention is shown in
FIG. 8, wherein the plug 30 is provided with a skirt portion 35 on the
outer circumference of the shoulder 33. This skirt portion forms a
trough around the shoulder portion of the plug such that when the
apparatus is inverted the bacter7al suspension 26 will rest within
the trough, thereby preventing any leakage of the suspension between
the cap portion of the plug and the inner wall of the upper portion of
the container 20, from occuring. This leakage will not normally occur
unless the apparatus is left in the inverted position for a sustained
period of time.
FIG. 8 also shows the open end portion of the microtubes 22
being provided w~th a relieved portion 36, at a point where the
microtubes meet the inside wall of the container 20. This relieved
portlon accepts the penetration of the skirt portion 35, thereby
permitting the open end portion of the microtube to come into direct
communication with the shoulder 33.
In FIG. 9, there is shown the application of numbers or symbols
40 to the outside of the container. These numbers or symbols designate
the different microtubes and facilitate the 7dentification of the
different test reagents as well as the test results. The base container
may also be provided with a gradient scaie 41 such that the operator
of the device can easily determine the volume of suspension introduced
into the central chamber or the amount of suspension contained in each of
the microtubes.
-16-
~ 092499 AHP-6880/6881
Still another embodiment of the present invention is shown
in FIGS. 10 and 11 wherein the upper cap portion 30a of the plug is
provided with extension 30c. The extension 30c protrudes above the
outer walls of the container 20 when the plug is in its final position.
This extension provides a means of attachment for a compression
compensator 49.
In many instances where the operator is testing a bacterial
suspension containing bacteria which are not communicable, the
apparatus can be used without compensator 49 and the air from within
the apparatus can be vented directly to the atmosphere. Where the
testing involves a bacterial suspension containing bacteria which are
contagious, it is preferred that any air vented from the venting passage
34 of the plug 30 to be safely contained within a closed chamber.
This provision is advisible since the air vented from passage 34 has
been in previous contact with the bacterial suspension 26. As a result
of such contact it is possible that a bacterial aerosol could be
released from vent 34 as the plug 30 is urged into its final position,
as shown in FIG. 7.
In order to eliminate the possible release of a bacterial
aerosol, the apparatus of the invention can be adapted with the
compression compensator assembly 49 shown in FIGS. 10 and 11. The
compression compensator 49 comprises a cylindrical hollow chamber 50
closed at its upper end portion 50a and open at its lower end portion 50b.
The lower end portion 50b is adapted to fit by friction or interference
in air-tight communication with the cap portion 30c of plug 30.
As shown in FIG. Il the cap portion 30c of the plug extends beyond
; the upper r1m of container 20 to fac11itate the fitting of the compression
assembly 49 to it.
Slidingly mounted within the interior portion of chamber 50 is
separation disc 51 having flange 51a disposed about the periphery of
the lower portion of the disc. The disc divides the chamber 50 into
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an upper and lower reglon, 52 and 53 respectTvely, such that the
volume thereof relative to each other is dependent upon the position
of disc 51 within the chamber. The upper region 52 is provided with a
venting aperture 54 which vents the air from the upper region to the
atmosphere.
Prior to the use of the compression compensator 49 in
conjunction with the biological testing device 10, the separation
disc 51, is brought to its lowest position within the compensator as
shown in FIG. 10. The entire compensator is then mounted on the top
of plug 30 by means of a simple press fit with the outer cap portion
of plug 30. In this position flange 51a bottoms on the top surface of
plug 30. When the separation disc 51 is in its initial or lowest
position, region 53 is of a smaller volume than region 52. Moreover,
region 53 is completely sealed from the upper region 52 as well as the
surrounding atmosphere while the upper region 52 Is free to vent to the
atmosphere through aperture 54.
When the plug 30 is inserted into container 20, subsequent to
the introducing of the inoculated bacterial suspension into the container
20, the air within the container 20 which has come into contact with the
bacterial suspension is vented through the plug by means of vent 34.
This "possibly contaminated" air is in this way introduced into region 53
the lower portion of the compression compensator 60. The introduction
of the contaminated air will cause an increase in pressure withTn region
53 which results in disc 51 moving upwardly, tFlG. Il) thereby increasing
the volume of the lower region 53. In this way it is possible for the
contamjnated air to be fully contained within the said lower region.
As the volume of the lower region 53 is increased, the volume of the
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uppor reglon 52 Is proportlonately decreased and the alr from the
upper region 52 which has not been contaminated is vented directly to
the atmosphere through venting aperture 54. It can be seen that none
of the contaminated air from within the container 20 can escape to the
outside atmosphere, but rather is completely contained within the
compression compensator 49.
The compression compensator may be constructed of a variety of
different materials. The use of a plastic resin such as polystyrene is
convenient not only because it is inexpensive and easily molded, but also
since it can be obtained in a transparent form. This transparency
enables the user to view the movement of the separatTon disc 51 during
use of the device, thereby providing a visual check that the air
vented from chamber 25 is being contained.
As with the biological testing apparatus itself, it is necessary
that the compression compensator form a number of substantially air tight
seals. The quality of these seals may be increased, if desired, by the
application of a number of inexpensive sealing rings. For example, as to
the seal formed between the lower open end of the compensator 49 and the
plug 30, a rubber gasket or washer may be located on the upper periphery
of the cap portion 30c of the plug, thereby increasing the quality of the
seal between the plug and the compensator. Also the seal formed between the
separation disc 51 and the inner walls of chamber 53 may be improved by fitting a
rubber 0-rirg around the outer circumference of the disc 51. Thus the
0-ring will be in constant frictional engagement with both the separation
disc and the inner wall of the compensator. It should be noted,
however, that this seal should not be so tight as to prevent the free
movement of the disc 51 within the compensator chamber 53.
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An alternate constructlon for Increaslng the quality of seal
between the separation disc 55 and the inner wall 50 of the compensation
49 is shown in FIG. 12. The separation disc 55 formed of flexible
material such as resin material is provided with an outer cylindrical
rim or flange 55a. This outer rlm 55a is provlded w1th upper and lower
annular lips 55b and 55c, respectively, which contact the inner wall
of the compensator. These lips form substantially two independent seals.
As a result any contaminated air which, after having been introduced Tnto
the lower region 53 manages to leak past the first seal formed between the
lower lip 55c and the inner wall of the compensator, will be blocked by
the second seal formed between the upper lip 55b and the inner wall
of the compensator. In this way leakage is prevented from entering the
upper region 52 and ultimately being vented to the atmosphere.
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