MANUALLY OPERABLE WASHER FOR MULTI WELL PLATES

Abstract: A manually operable washer for simultaneously wash­ ing a number of wells of a multi well plate comprising a manifold (1) comprising a liquid supply channel (2) and a suction channel (3), said channels being connected with a number of liquid supply pipes (9) and suction pipes (18), respectively, each suction pipe (18) being mounted parallel with and adjacent to a liquid supply pipe (9), a valve through which the liquid supply channel (2) can be connected with a source of liquid, and means for connecting the suction channel (3) with a source of vacuum. The washer permits a quick and efficient selective washing of a number of wells of a multi well plate.

Description: Manually operable washer for multi well plates This invention 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 multi well plate with a liquid, such as water, are commercially available. When multi well plates which typically comprise 96 wells arranged in 8 rows, each comprising 12 wells are used for testing purposes, only some rows of wells are ordinarily used in each test series. However, the prior art washers do not permit part of the 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 further 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 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 labour-consuming and might cause test errors due to a non-uniform washing of the wells. Therefore, there is a need for providing a washer for simultaneously and uniformly washing part of the wells of a multi well plate. This need is fulfilled with the washer of the invention, said washer being characterized in that it comprises a manifold comprising a liquid supply channel and a suction channel, said liquid 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 parallel with and adjacent to a liquid supply pipe, that the liquid supply channel via a valve is connected with means for connecting said liquid supply channel with a source for washing liquid and that the suction channel is connected with 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 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 of the suction pipes are located at the level of the upper edges of the wells so as to prevent excessive amounts of washing liquid from flowing from one well into 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 suction 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 preferably located at a 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 bottom parts of said wells. The manifold preferably is a block, e.g. of a plastics material, in which a bore forms 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 preferably 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 distributor channels. By providing distributor channels extending all way through the block manifold, a distributor channel can readily 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 introduced 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 connection with multi well plates of the above mentioned type, 8 or 12 pipes are preferably 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 be washed or a coating, if any, on said bottoms, the washer of the invention preferably comprises at least one and preferably two spacers provided at the underside of the manifold block. These spacers may consist of a fixed cylindrical core and an interchangeable bushing mounted on said core. An O-ring is preferably provided on the cylindrical cylinder 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 and is maintained 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 cleaned. The means for connecting the liquid supply channel with the source of washing liquid and the means for connecting the suction channel with a source of vacuum are preferably pipe stubs made from a plastics material and inserted into bores in the manifold block. A further important advantage of the apparatus of the invention is that in case the liquid supply channel or a liquid supply pipe is blocked, it can be cleaned simply by connecting the pipe stub communicating with the liquid supply channel with the source of vacuum. A suitable source of vacuum is a water jet pump. The invention will be described in further detail with reference to the drawings, in which Fig. 1 shows a top view of a preferred embodiment of the washer of the invention, Fig. 2 is a sectional view along the line Il-Il of the wa sher illustrated in Fig. 1, except that the valve has been removed, Fig. 3 is a sectional view along the line Ill-Ill of the washer illustrated in Fig. f, and Fig. 4 is a vertical sectional view in large scale of a valve and the adjacent part of the mainfold block of the washer illustrated in Figs. 1-3. The washer illustrated in the drawings comprises a manifold in the form of a block 1 comprising two internal longitudinally extending channels, viz. a liquid supply channel 2 and a suction channel 3. The liquid supply channel 2 is at one end connected with a bore 4 having provided therein a valve which will be described below. The opposite end of the liquid supply channel 2 is closed by a 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 of the block and perpendicular to the 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 into said portion 7. A liquid supply pipe 9 extending some distance out from the block 1 is inserted in the lower portion of each channel 6. At the bottom surface of the block 1 there is provided holes having inserted therein spacer cores 10 having on their surfaces annular grooves in which O-rings 11 are mounted. The two spacer cores 10 are each surrounded by an interchangeable bushing 12. A channel 13 connects the bore 4 with the exterior side of the block 1 and a pipe stub 14 is inserted in said channel 13. Another 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 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 perpendicularly from the suction channel 3 and each having inserted therein a suction pipe 18 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 in Fig. 4 is provided in the bore 4 of the block 1. The valve consists of a valve body 19 having a lower portion 20 of a greater diametre than the upper portion 21. In 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 0-ring 23 is mounted is provided on the exterior surface of the upper portion 21 of 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 screwed into the lower portion of the bore 4 and which is sealed to the block 1 by means of an 0-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 cannot move upwardly through the bore 4. The block 1 is sealed relative to the lower portion 19 of the valve body by means of an 0-ring 27 which is provided in the transition zone between the upper and the lower portion of the bore 4. When the valve body 19 is pressed down, the zone 22 having 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 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 19 upwardly and thus disconnect the channels 13 and 2.

Claims: Claims 1. A manually operable washer for washing the wells of multi well plates with a liquid, c h a r a c t e r i z e d in that it comprises a manifold (1) comprising a liquid supply channel (2) and a suction channel (3), said liquid supply channel (2) being connected with a single row of parallel liquid supply pipes (9) and the suction channel (3) being connected with a corresponding number of suction pipes (18), each suction pipe (18) being located parallel with and adjacent to a liquid supply pipe (9), that the liquid supply channel (2) via a valve is connected with means (14) for connecting said liquid supply channel (2) with a source of washing liquid, and that the suction channel (3) is connected with means (16) for connecting the suction channel (3) with a source of vacuum. 2. A washer according to claim 1, c h a r a c t e r i z e d in that the ends of the suction pipes (18) are located at a longer distance from the manifold (1) than the ends of the liquid supply pipes (9). 3. A washer according to claim 1, c h a r a c t e r i z e d in that the manifold consists of a block (1) in which a bore forms a liquid supply channel (2) which is located parallel to another bore forming the suction channel (3), and in which the liquid supply pipes (9) are inserted in the lower end of distribution channels (6) extending from the top surface of the block (1) through the liquid supply channel (2) to the bottom surface of said block, the upper portion (7) of the distribution channels (6) being closed by removable closure means (8). 4. A washer according to claim 3, c h a r a c t e r i z e d in that cylindrical spacer cores (10) having interchangeable surrounding bushings (12) are provided on the underside of the block (1). 5. A washer according to claim 1, c h a r a c t e r i z e d in that the valve is mounted in a bore (4) in the block (1).

Inventors: CAPPELEN, JORGEN, NIELSEN, BORGE
Applicants: A/S NUNC
Application year: 1982
Main classification: B01L11
IPC codes: B08B3, B01L11, A47L17