Patent Grant
8043685
The present invention relates to a sheet used in a liquid dispensing container for a liquid handling system used in chemical experiments and the like and a container using the sheet.
In a liquid handling system used in chemical experiments and the like, liquid is transferred (dispensed) into and out of a liquid dispensing container (hereinafter, referred to as a “tank” in the description) using a tip for a pipet (hereinafter, simply referred to as a “tip” in the description) for subsequent tests.
When dispensing a relatively low volatile liquid (water, various salt solutions and the like) to a tank, an open-topped tank 50, shown in
On the contrary, when dispensing a relatively high volatile liquid (organic solvent, such as ethanol, methanol and acetonitrile) to a tank, the opening of the tank 50 is usually closed with a lid 52 because the liquid may lose in weight owing to its high volatile characteristics. And, when the liquid is dispensed into and out of the tank 50 using a tip 51, the lid 52 is detached from the tank 50.
However, in a case in which the tank 50, shown in
Furthermore, as a tip 51 for a pipet, one made of resin having a higher chemical resistance than one made of metal has been in use. So, in view of sealing property of the tank, a septum, what is called, is proposed. However, the septum is only used for inserting a metal tip (needle) and therefore cannot resist several time of inserting and drawing of the tip. So, the septum is not applicable for practical use.
Consequently, to employ a tip made of resin, as shown in
To solve the problems, a tank 50 the opening of which is covered with a sheet 53 having a plurality of radial slit 55, as shown in
The radial slits 55 are formed corresponding to the tips 51. For example, when a series of eight tips 51 are used, the sheet 53 has eight of the radial slits 55.
However, when frequent inserting and drawing of the tip 51 increase, a friction between the slit 55 and the chip 51 deforms the radial pieces 55a and 55b of each slit 55. Consequently, sealing performance of the tank 50 still remains low.
Accordingly, the object of the present invention is to provide a sheet applicable for closing an opening of a liquid dispensing container for a liquid handling system used in chemical experiments, in which the sheet is capable of preventing natural volatilization of a liquid in the container even if the tip is frequently inserted and drawn, and also facilitating inserting and drawing of the tip.
The inventors of the present invention carried out an in-depth study to accomplish the object. As a result, he has found this object can be accomplished by using a sheet produced by stacking specific sheets.
The present invention has been accomplished based on the above finding and provide a composite sheet comprising a sheet having elastic property and another sheet having slip property wherein the sheets are stacked.
And, the present invention provides a container for dispensing liquid contained therein through an opening which is covered with a composite sheet comprising a sheet having elastic property and another sheet having slip property wherein the sheets are stacked.
According to the present invention, the slip property of the sheet allows the tip to be inserted and drawn with small resistance. And, the elastic property of another sheet shows restoring force to restore the sheet. Accordingly, the container is maintained sealed regardless of the number of inserting and drawing of the chip. In addition, when the tip of the pipet is drawn out of the container after sucking liquid from the container, the tip is wiped with the slit pieces of the sheet, whereby excess liquid attached to the outer surface of the tip, such as droplets attached to the tip, can be removed. So, a predetermined amount of the liquid can be correctly measured.
Hereinafter, preferred embodiments of a composite sheet of the present invention will be described.
A composite sheet according to the present invention comprises a sheet having elastic property and another sheet having slip property wherein the sheets are stacked.
A composite sheet of the invention is employed for closing an opening of a liquid dispensing container for a liquid handling system used in chemical experiments. Specifically, the composite sheet is employed for closing an opening through which liquid is dispensed in and out of a liquid dispensing container. That is, the composite sheet of the present invention can be employed as a sheet for closing an opening of a liquid dispensing container.
Hereinafter, a case in which a composite sheet of the present invention is employed for closing an opening of the aforesaid container will be described referring to the drawings.
As shown in the figures, the tank 10 is equipped with the sheet 20 which covers the opening 11 of the tank 10.
Usually, the opening 11 is equipped with a base plate 30 for supporting the sheet 20, and the sheet 20 is placed on the base plate 30.
And, on the sheet 20, a clamp plate 40 is placed.
The tank 10 may be made of any materials used in a container for a liquid handling system used in chemical experiments without limitation, preferably, made of materials having resistance to organic solvents because the tank is sometimes used for containing chemical solvent. As such materials, polyethylene, polypropylene and polycarbonate may be given.
The base plate 30 may be made of any materials used in a base plate for a liquid handling system used in chemical experiments without limitation. As such materials, polyethylene, polypropylene, polycarbonate, polytetrafluoroethylene, stainless steel, aluminum and polyimide may be given.
The clamp plate 40, made of metal plate, clamps the sheet 20 between the base plate 30 and itself due to its own weight for restricting deflection and displacement of the sheet 20.
The base plate 30 is formed with pluralities of bores 30a, and the clamp plate 40 is formed with pluralities of bores 40a. The bores 30a and the bores 40a are arranged in the same positions as slits, described below, in the vertical direction.
The composite sheet 20 comprises a “A” sheet 21 and a “B” sheet 22 wherein the sheets are stacked.
The “A” sheet 21 is made of sheet materials having small resistance for inserting and drawing the tip 51, that is, sheet materials having slip property. Specific preferable examples of sheet materials having slip property may be ones having both coefficient of dynamic friction and coefficient of static friction, the both of the coefficients being 0.2 or lower, depending on materials and shapes of the tip and shapes of the slit. The coefficient of dynamic friction and the coefficient of static friction are measured in accordance with ASTM-01894-63.
As the sheet materials having slip property, polypropylene (PP) and polyethylene (PE), polymethylpentene(PMP), each having a thickness of 0.5 mm or smaller, and polytetrafluoroethylene (PTFE) having a thickness of 1 mm or smaller will be specifically given. Especially, PTFE is an ideal sheet material because of its small coefficient of friction of 0.1 to 0.05 or smaller.
The “B” sheet 22 is made of sheet materials having elastic force for restoring the slit pieces (shown in
As the sheet materials having elastic property, sheet materials having hardness Hs of 30° to 90° and coefficient of restitution of 20% to 50% are preferably selected depending on materials and shapes of the tip and thickness of the sheet. Specifically, silicon rubber having a thickness of 0.5 to 1.0 mm is preferably employed. The hardness is measured in accordance with JIS K 6253 and the coefficient of restitution is measured in accordance with JIS K 6253.
In exchange of silicon rubber, fluorocarbon rubber, perfluoro (perfluoro elastomer) rubber, nitrile rubber, chloroprene rubber, ethylene-propylene rubber and polyimide resin may be given. The kind of the sheet material is selected depending on heat resistance, chemical resistance and oil resistance according to liquid contained in the tank. If employed under an area requiring light shielding (RI and the like), the sheet made of sheet materials which hardly transmits light, such as black silicone rubber and black fluorocarbon rubber, may be selected for light shielding.
In order to improve sealing performance, a supporting tool having no slit and hole may be placed on the “B” sheet. The supporting tool may be made of polyimide and aluminum.
The A sheet 21 and the B sheet 22 may be arranged such that the both sheets are simply stacked or bonded with adhesive. When the both sheets are bonded together, at least one sheet may be coated by a coating method.
Each of the A sheet 21 and the B sheet 22 is preferably formed with a slit (a cut). And, the slit may be shaped into a radial shape (shown in
The slit may be formed to cut the sheet completely or incompletely. That is, the slit does not need to penetrate through the sheet in the thickness direction or may terminate at the middle of the sheet in the thickness direction.
By using the sheet having the aforesaid shaped slits, the container will be maintained sealed while a reaction continues and thus a procedure for transferring liquid out of the tank using a tip is not carried out, because the slit is not penetrated through the sheet. In addition, the tip can be easily inserted to the container through the slit when the liquid after the reaction is transferred out of the tank using the tip. That is, since the slits terminate at the middle in the thickness direction of the sheet, the tip tears the sheet easily at the slit so as to penetrate through the sheet.
In addition, when the tip of the pipet is drawn out of the tank after suction of liquid, the outer surface of the tip is wiped with the slit pieces of the sheet. Therefore, excess liquid attached to the surface of the tip, such as droplets attached to the surface of the tip, is removed. Accordingly, a predetermined amount of liquid can be measured correctly.
As a suitable example employing the container, a laboratory device necessary for genetic manipulation in molecular biology field, that is PCR (polymerase chain reaction), will be given The PCR is a method for amplifying a small amount of target specific DNA sequences using heat-resistant DNA polymerase in a container.
Conventionally, in such a type of PCR, liquid is repeatedly reacted for about 25 times at a temperature cycling, for example, from 55° C. to 94° C. By the reaction, the inside of the container becomes a high pressure and high temperature state. In order to prevent volatilization of the liquid, the container is tightly sealed with a lid until the reaction finishes.
So, it is not easy to transfer the liquid out of the container because the container is tightly sealed with the lid. When the liquid is transferred out of the container, the lid which tightly seals the container has to be removed. This procedure complicates the experiment work.
In order to resolve the complication, the container may be sealed with “the aforesaid sheet having the slits penetrating the sheet incompletely”. By using this sheet, the container can be maintained at the sealed condition during the reaction, and the tip can be easily inserted through the slit when the solvent is transferred out of the container.
Next, a dispensing work using the sheet 20 formed with the radial slits will be described referring to
The dispensing work is explained as for one tip 51. Firstly, the distal end of the tip 51 is inserted into the radial slit 21a formed at the A sheet 21 through the opening 40a of the clamp plate 40. As shown in
Then, in the same way, the distal end of the tip 51 is inserted into the slit 22a of the B sheet 22, shown in
When the tip is drawn out, each of slit pieces 21b, 21c of the slit 22a is resiliently restored because of large elastic property of the B sheet 22. As a result, the slit is closed with the slit pieces 21b and 21c for maintaining the container 10 at the sealed condition. Besides, the A sheet 21 is not worn by friction with the tip 51 because of its slip property.
As mentioned above, easy inserting and drawing of the tip and sealing performance of the tank can be maintained even though inserting and drawing of the tip 51 are frequently conducted.
The aforementioned result can be applied to a case in which a number of the tip 51 is not only one but also plural (8 in the example shown in
The radial slits 21a and 22a formed at the A sheet 21 and the B sheet 22 respectively are shaped to radiate out from centers 21o and 22o. In this case, depending on a thickness of the sheet, a slit may be extended and, for example, may be communicated with adjacent slits and may end up spreading over the sheet. This leads to lowering operationality. To avoid this, ends of the slit are terminated with bores or lines, if necessary.
The slits 21a and 22a are arranged in such a manner that the centers 21o and 22o are located at the same position in the vertical direction, and that the cut lines of the slits are substantially conformed each other on plane so as to achieve smooth inserting and drawing of the tip 51. On the contrary, as shown in
The slit may have any shapes, without limitation, capable of smoothly inserting and drawing the tip, for example, shapes shown in
A composite sheet according to the present invention comprises a sheet having elastic property and another sheet having slip property wherein the sheets are stacked. In the present invention, the sheets may or may not have the same shape. When the sheets have the same shape, the cut lines of the slits may or may not be conformed to each other.
Heretofore, a case of the liquid dispensing container (tank) 10 having one opening 11, that is, the container having one storage space for liquid, has been described; however, the liquid dispensing container according to the present invention is not limited to.
Accordingly, the present invention can be applicable to the tank 10, shown in
The sheet 20 which covers the tank 10 is formed with the slits (21a and 22s), same as the above-mentioned, correspondent to the openings 11 shown in
A liquid dispensing container shown in
The container is covered with the sheet, not shown, such that the slits of the sheet are positioned above the tubular tanks 10 respectively, as the same way mentioned-above. The tubular tank 10 may be one at minimum. Alternatively, when plural dispensing works are carried out, the tubular tank 10 may be formed in plural equal to the number of the dispensing works. In any cases, the container significantly contributes on high efficiency and speeding up of the dispensing work.
As mentioned above, the clamp plate 40, made of metal plate, clamps the sheet 20 between the base plate 30 and itself due to its own weight for restricting deflection and displacement of the sheet 20. When pluralities of tips 51 (96 in the example shown in
In the liquid dispensing container equipped with pluralities of tubular tanks 10 shown in
The present invention is hereinafter to be described more specifically by the following examples. Such examples, however, are not to be construed as limiting in any way the scope of the present invention.
The tank of the container was examined for volatile property using the container shown in
As the sheet, one having the radial slits (shown in
In addition, the sheets, made of the same material, were stacked by displacing the cut lines of the slits of the sheets at about 22.5° and employed for the same volatile property test (hereinafter, referring to as a displaced type).
Furthermore, the sheets, made of the same material and having no slit, were stacked and employed for the same volatile property test (hereinafter, referring to as a sealed type). Furthermore, the container, in which 20 ml of acetonitrile was poured, was left to stand in a refrigerator at 4° C. without the sheet placed thereon and employed for the same volatile property test (hereinafter, referring to as a no-lid type).
Results are shown in Table 1. A numerical value in Table 1 means an amount (ml) of acetonitrile remaining in the tank. The results are also shown in
As shown in Table 1 and
In this example, the sheet was examined for durability to inserting and drawing of the tip. The test was carried out by using the container used in Example 1. And, the displaced type sheet in Example 1 was used. 10 ml of acetonitrile was poured in the tank, the tip was inserted through the slit into the tank and sucked 0.2 ml of acetonitrile, and then the sucked acetonitrile was placed back. Then, the tip was drawn out of the tank through the slit and reinserted through the slit. This procedure was repeated for 100 times at 20° C. The procedure period was 200 seconds. This series of procedure was repeated for 3 times. Then, acetonitrile remaining in the tank was weighed for obtaining a residual amount of acetonitrile. The result was shown in Table 2.
The displaced type sheet was examined by the naked eye whether or not the sheet was deformed. As the result, the sheet having slip property showed small deformation; however, the sheet having elastic property showed no deformation. So, it was found that conducting the inserting and drawing test about 100 times hardly deforms the composite sheet according to the present invention, whereby the test was smoothly carried out. As for volatilization of liquid, the container having no lid showed volatilization of a small amount of acetonitrile within 200 seconds; however, the container covered with the sheet according to the present invention shows little volatilization of acetonitrile. Accordingly, the sheet according to the present invention can maintain the container to be sealed even if the tip was inserted and drawn repeatedly.
The tank of the container was examined for volatilization of water using the container shown in
The sheet having a radial slit, the cut lines of which were conformed each other (shown in
Results were shown in Table 3. A numerical value shown in Table 3 means a ratio of an amount of the water remaining in the tank to the first amount of the water, which was represented by a capacity ratio. The results were also shown in
As shown in Table 3 and
| Number | Date | Country | Kind |
|---|---|---|---|
| 2004-091741 | Mar 2004 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2005/005684 | 3/28/2005 | WO | 00 | 12/14/2007 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2005/092734 | 10/6/2005 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 4362698 | Boosalis et al. | Dec 1982 | A |
| 20040096622 | Razavi et al. | May 2004 | A1 |
| Number | Date | Country |
|---|---|---|
| 58-32345 | Aug 1981 | JP |
| 58-46777 | Mar 1983 | JP |
| 5-154962 | Jun 1993 | JP |
| 08-301322 | Nov 1996 | JP |
| 10-132713 | May 1998 | JP |
| 11-241718 | Sep 1999 | JP |
| 2003-236989 | Aug 2003 | JP |
| Number | Date | Country | |
|---|---|---|---|
| 20080210691 A1 | Sep 2008 | US |
