Note: Descriptions are shown in the official language in which they were submitted.
This invenlion relates -to a manually operable washer for
washing the wells of multi well plates with a liquid.
Automatic washers for simultaneously washing all wells of a
mul-ti well plate with a liquid, such as water, are commercially avail-
5 able.
When multi well plates which typically comprise ~ wellsarranged in 8 rows, each comprising 12 wells are used for testing
purposes, only some rows of wells are ordinarily used in each test
series. ~lowever, -the prior ar-t washers do not permit part o-F -the
10 wells to be selectively washed. This is a serious drawback of the
prior art washers because the unused washed wells ordinarily cannot
be used for fur-ther test series. Consequently, the whole test plate
has to be thrown away. This drawback is particularly serious in case
the interior surface of the wells is coated with a substrate or the
15 plate has been subjected to other treatments.
The problem discussed above could be solved by washing
each well separately. However, such a procedure would be slow and
!abour-consuming and might cause -test errors due to a non-uniform
washing of the wells. Therefore, there is a need for providing a
20 washer for simultaneously and uniformly washing part of the wells ot
a multi well plate.
This need is -Fulfilled with the washer of the inven-tion,
said washer being characterized in that it comprises a manifold
comprising a liquid supply channel and a suction channel, said liquid
25 supply channel being connected with a single row of parallel liquid
supply pipes and the suction channel being connected with a similar
number of suction pipes, each suction pipe being located paral lel
with and adjacent to a liquid supply pipe, that the liquid supply
channel via a valve is connected with means for connecting said
30 liquid supply channel with a source for washing liquid and that the
suction channel is connected wi th means for connecting the suction
channel with a source of vacuum.
When the washer of the invention is connected with a
source of washing liquid and the valve is opened, washing liquid
35 may be supplied to the liquid supply pipes and from these pipes it
Flows into the wells to be washed.
In the initial phase of a washing procedure the washer is
preferably held at such a distance above the wells that the free ends
o-F the suction pipes are locatecl at the level of the upper edges of
-~he wells so as to prevent excessive amounts of washing liquid -from
flowing from one well in-to an adjacent well.
When the wells have been filled, the valve is closed so as
to stop the supply of liquid and the apparatus of the invention is
moved downwardly to a position in which the lower ends of the suc-
tion pipes are located a short distance above the bottoms of the
wells. During this movement liquid is continuously sucked out of the
wells and the wells ordinarily are empty when the above mentioned
lower position has been reached. The apparatus is then raised to the
starting position and the washing operation may be repeated e. g . 2-3
times .
The ends of -the suction pipes, which pipes preferably are
made from stainless steel, are prefsrably located at 3 longer distance
from the manifold than the ends of the liquid supply pipes so as to
allow the ends of the suction pipes to be moved down to the bottoms
of wells having round bottoms without risking contact between -the
ends of the liquid supply pipes and the rounded bot-tom parts of said
wells .
The manifold preferably is a block, e.g. of a plastics
material, in which a bore forrns a liquid supply channel which is
located parallel to another bore forming the suction channel. The
liquid supply pipes, e.g. thin pipes of stainless steel, are preferab-
ly mounted in the lower part of distributor channels in the form of
bores extending -from the top surface through the liquid supply
channel to the bottom surface oF the manifold block, the upper ends
of said distributor channels being closed by removable closure means.
The closure means are preferably screws, such as Umbraco~ screws,
having an external thread corresponding to an internal thread in the
upper ends of said ciistributor channels.
By providing distributor channels extending all way
through the block manifold, a dis-tributor channel can reaclily be
cleaned in case a liquid supply pipe is blocked during use. Thus,
the screw in the upper end of -the distributor channel is merely
removed and a wire or a similar thin member is introcluced into the
distributor channel and the blocked liquid supply pipe.
The number of liquid supply pipes may vary within broad
ranges but when the washer of the invention is to be used in con-
~lt~
nection with mul-ti well plates of the above mentioned -type, ~ or 12
pipes are pre-ferably employed.
In order -to prevent the ends of the liquid supply pipes or
suction pipes from contacting the bottoms of the wells which are to
5 be washed or a coating, if any, on said bo-t-toms, the washer of the
invention preferably comprises a-t least one and preferably two spa-
cers provided at the underside of the manifold block. These spacers
rnay consist of a fixed cylindrical core and an interchangeable bush-
ing mounted on said core.
An O-ring is preferably provided on the cylindrical cylin-
der surFace of the core in order to maintain the bushing thereon in
a fixed position. By using interchangeable bushings, -the distance
between the underside of the manifold block and the well plates to
be washed can be adjusted relative to the depth of the wells.
The valve controlling the liquid supply to the liquid supply
channel is preferably a spring activated valve which in its position
of rest prevents washing liquid from flowing into the liquid supply
channel and which can be opened by a slight finger pressure. The
valve is preferably mounted in a further bore in the manifold block
20 and is rnaintained in said bore by a bottom screw which is screwed
into said bore. Thus, the valve can easily be dismantled and both
the movable parts of the valve and the bore can readily be cieaned.
The means for connecting the liquid supply channel with
-the source of washing liquid and -the means for connecting the suc-
25 tion channel with a source of vacuum are preferably pipe stubs madefrom a plastics material and inserted into bores in the mani-Fold
block .
A further important advantage of the apparatus of -the in-
vention is that in case the liquid supply channel or a liquicl supply
30 pipe is blocked, it can be cleaned simply by connecting the pipe
stub communicating with the liquid supply channel with -the source of
vacuum .
~ suitable source of vacuum is a water jet pump.
The invention will be described in further detail with re-
3~ ference to the drawings, in which
Fig. 1 shows a top view of a preferred embodiment ofthe washer of the invention,Fig. 2 is a sectional view along the line ll-ll of the wa-
sher illustra-ted in Fi~. 1, except thdt the valve
has been removed,
Fig . 3 is a sectional view along the line l l l-l l l of the
washer illustrated in Fig. 1, and
Fig. 4 is a vertical sectional view in large scale of a
valve and the adjacent par~ of the mainfold block
of the washer illustrated in Figs. 1-3.
The washer illustrated in the drawings comprises a mani-
fold in the form of a block 1 comprising two internal longitudinally
10 ex-tending channels, viz. a liquid supply channel 2 and a suction
channel 3.
The liquid supply channel 2 is a-t one end connected with a
bore 4 having provided therein a valve which will be described be-
low. ~he opposi-te end of the liquid supply channel 2 is closed by a
15 screw 5 having an external -thread corresponding to an internal
thread in said channel.
In the washer illustrated the block 1 comprises 8 channels
6 extending from the top surface of the block 1 -through -the channel
2 and to the bottom surface o-f the block and perpendicular to the
20 channel 2.
The portion 7 of each channel 6 located above the channel
2 comprises an internal thread, and a screw 8 having an external
thread is screwed in-~o said portion 7. A liquid supply pipe 9 extend-
ing some distance out from ~he block 1 is inser~ed in the lower por-
25 tion of each channel 6.
At the bottom surface of the block 1 there is providedholes having inserted therein spacer cores 10 having on their sur-fa-
ces annular grooves in which O-rings 11 are mounted. The -two
spacer cores 10 are each surrounded by an in-terchangeable bushing
30 12.
-~ A channel ~ connects the bore ~ with the exterior side of
the block 1 and a pipe stub 1~ is inserted in said channel 13. Ano-
ther channel 15 connects one end of the suction channel 3 with the
exterior side of the block 1, and a pipe stub 16 is inserted in the
35 channel 15. The opposite end of the suction channel is closed by a
screw 17 having an external thread corresponding to the internal
thread of said channel.
The block 1 further comprises 8 channels extending per-
pendicularly from -the suction channel 3 and each having inserted
therein a suction pipe 1~ extending a few millimetres longer out -From
the block 1 -than the corresponding liquid supply pipes 9.
As mentioned above the valve which is illustrated in detail
5 in Fig. 4 is provided in -the bore 4 of the block 1. The valve con-
sists of a valve body 19 having a lower portion 20 o-f a greater
diametre than the upper portion 21 . I n the zone between the upper
portion 21 and the lower portion 20 of the valve body it comprises a
zone 22 of reduced diametre. An annular groove in which an O-ring
10 23 is mounted is provided on the ex-terior surface of the upper
portion 21 o-F the valve body.
The underside oF the valve body is hollow and the upper
end of a coil spring 24 is inserted in said hollow portion. The lower
end of the coil spring 24 rests on a bottom screw 25 which is screw-
15 ed into the lower portion of -the bore 4 and which is sealed to the
block 1 by means o-F an O-ring 26. The lower portion of the bore 4
has a greater diametre than its uppor portion and the lower portion
of the valve body 19 canno-t move upwardly through the bcre 4.
The block 1 is sealed relative to the lower portion 19 of -the valve
20 body by means of an O-ring 27 which is provided in the transition
zone between the upper and the lower por-tion oF the bore 4.
When the valve body 19 is pressed down, -the zone 22 hav-
ing a reduced diametre is moved into the zone in which the channel
13 opens into the bore 4, and the liquid supply means are brought
25 in communication with the liquid supply channel 2, thus permitting
washing liquid to flow out -through the liquid supply pipes 9.
When the pressure on the valve body 19 is relieved, -the
coil spring 24 will Force the lower portion of the valve body 29 up-
wardly and thus disconnect the channels 13 and 2.
~5
