Chemical apparatus and process disinfecting – deodorizing – preser – Analyzer – structured indicator – or manipulative laboratory... – Means for analyzing gas sample
Reexamination Certificate
2001-05-08
2004-08-17
Warden, Jill (Department: 1743)
Chemical apparatus and process disinfecting, deodorizing, preser
Analyzer, structured indicator, or manipulative laboratory...
Means for analyzing gas sample
C422S105000, C422S105000
Reexamination Certificate
active
06776964
ABSTRACT:
The invention relates to a sealing mat for sealing test tubes, in particular to a sealing mat comprising a carrier sheet provided with a multiplicity of sealing elements for sealing test tubes.
A sealing mat of this type is known in practice. In this known sealing mat the carrier sheet and the sealing elements are made as an integral whole from one material and permanently joined to one another. Such sealing mats are used in particular with storage and reagent means, such as test tubes (also termed microtubes), microtitration plates and “Deepwell” blocks (these are test tubes permanently joined to one another). In this case the test tubes are in general grouped in a cluster in accordance with an 8×12 matrix pattern. A major advantage of such mats is that it is possible by this means as it were to open and to seal a large number of test tubes at the same time in a single operation. One disadvantage of the known sealing mat, amongst others, is that opening the test tubes is not always equally easy. The sealing elements sometimes have the tendency to remain firmly seated in the test tubes, in which case a substantial force then has to be exerted on the mat in order to remove the mat, under the influence of which force the mat has the tendency to stretch and also to lift the tube concerned, and also other tubes, out of the rack. Another disadvantage is that soiling or contamination can occur in other test tubes when the sealing mat is removed. A further major disadvantage is that all test tubes have to be opened in order to gain access to one test tube. A further disadvantage is that tools must be used if an individual (single) sealing element has to be fitted.
Within the scope of the invention a test tube is to be understood to be a container for storing substances, either in liquid form, powder form, solid form or in combinations thereof, for the purposes of chemical analyses, sample storage, performing chemical reactions in the test tube, etc. Such test tubes can have sizes ranging from small test tubes, such as so-called “microtubes” with a capacity of the order of 0.2 ml (or possibly less), to large test tubes having a capacity of 10 ml or more. Within the scope of the invention a test tube must also be understood to be composite storage and reagent means, such as microtitration plates and Deepwell blocks.
U.S. Pat. No. 5,282,543 discloses a sealing mat for sealing test tubes placed in a matrix pattern. According to a second embodiment of U.S. Pat. No. 5,282,543, the sealing mat consists of a sheet-like body that joins together a number of nodules which act as sealing elements and are arranged in a matrix pattern corresponding to the test tubes. The sheet-like body is provided with passages diagonally between every two adjacent nodules in order to guarantee adequate circulation of air for the purposes of heat transfer from a contact block to the underside of the sheet-like body. The entire teaching of U.S. Pat. No. 5,282,543 is directed towards the nodules being permanently attached to the sheet-like body.
EP-A 0 836 884 discloses a sealing system consisting of so-called inner sealing means and outer sealing means. The inner sealing means consist of cylindrical components which are to be placed within the open top end of a test tube and are sealed at their tops by a flat plate-like component having therein an optionally open, pre-formed passage for the point of a pipette. A number of inner sealing means are joined to one another by joining strips to give a matrix-like pattern. In this case there is no question of a carrier sheet and EP-A 0 863 884 also does not teach that the inner sealing means can be separated from one another. For sealing, in particular, the passages in the inner sealing means EP-A 0 836 884 provides outer sealing means in the form of a large sheet that is placed over the test tubes provided with inner sealing means and is pressed down onto these to produce a seal. However, this large sheet is not a carrier sheet for the cylindrical components of the inner sealing means.
The aim of the present invention is to provide an improved sealing mat for sealing test tubes.
This aim is achieved according to the invention in that the carrier sheet, on the one hand, and the sealing elements, on the other hand, are made of different materials, such as plastics. As a result of making the carrier sheet and the sealing elements for the sealing mat of different materials it becomes possible, inter alia, to use one material for the sealing elements, which, on the one hand, has very good sealing properties, and to use a material for the carrier sheet which, on the other hand, has properties which are favourable with respect to removing the sealing mat from the test tubes. These sealing properties on the one hand and removal properties on the other hand can then be mutually incompatible.
By making the carrier sheet and the sealing elements for the sealing must of different materials it becomes possible to assign another material to one of the elements, without the characteristics of the other material being affected. Examples are different colourings or different chemical resistance. However, making the carrier sheet, on the one hand, and the sealing elements, on the other hand, of different materials also offers yet further advantages. Since the sealing elements have to seal test tubes, special requirements are generally imposed on these in connection with chemical resistance.
So that the sealing elements have a good sealing action it is advantageous, according to the invention, if the sealing elements are made from a flexible and/or resilient material. This makes a close fitting seal of the sealing element on the test tube possible.
According to a particularly preferred embodiment of the sealing mat according to the invention it is highly advantageous if the sealing elements are attached to the carrier sheet such that they can be removed. In particular, this makes it possible to be able to open, independently of one another, the test tubes sealed by means of the sealing elements. After sealing the test tubes the carrier sheet can, for example, be removed, after which each of the test tubes is individually sealed and can also be moved individually in the sealed state.
According to a particular further embodiment of the invention it is advantageous if the sealing elements are attached to a carrier sheet in such a way that they detach from the carrier sheet when the latter is pulled back, while folding it over towards the rear, after sealing one or more test tubes. Pulling the carrier sheet back while folding it over towards the rear, that is to say pulling it back in a direction essentially transverse to the longitudinal direction of the test tubes, prevents a force acting in the longitudinal direction being exerted on the test tubes, which force could lift the test tubes from their container or rack. The sealing mat with which sealing elements are detachably attached to the carrier sheet has the additional advantage that said mat can be employed more easily in an automated process. According to a further embodiment guides are therefore also provided on opposing sides of the mat.
From the production engineering standpoint the join between the sealing elements and the carrier sheet can be produced simply and reliably if the sealing elements are provided with a peripheral groove in which the edge of the opening made in the carrier sheet is accommodated. With this arrangement the production procedure can be as follows:
A sheet having one opening per sealing element is first formed, for example by punching the desired number of openings in the desired positions in a sheet of suitable material. This sheet is then placed taut in an injection moulding mould, such that each opening is located at the position of the mould cavity for a sealing element. The edge of the opening in the carrier sheet will then project somewhat into the mould cavity in order to be incorporated or embedded in the sealing element on injecting the material for that sealing element. Depending on, inter a
Kramer Bartholomeus Wilhelmus
Verton Cornelis Johannes
Wijnschenk Ronald Josephus Clemens
Bachman & LaPointe P.C.
Handy Dwayne K
Micronic B.V.
Warden Jill
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