Chemical apparatus and process disinfecting – deodorizing – preser – Control element responsive to a sensed operating condition
Reexamination Certificate
2000-05-26
2003-03-18
Fortuna, Ana (Department: 1723)
Chemical apparatus and process disinfecting, deodorizing, preser
Control element responsive to a sensed operating condition
C422S063000, C422S064000, C422S051000, C422S067000, C422S091000
Reexamination Certificate
active
06534017
ABSTRACT:
The field of the present invention is the storage of test elements such as those used to detect analytes in sample liquids. Such test elements are used especially in the field of urine analysis and in the field of blood sugar determination. In addition test elements are widely used in environmental analysis. Another field of increasing importance relates to immunological tests e.g. the detection of drugs, HCG and HIV in blood and urine.
The test element is contacted with a sample in order to detect an analyte or to analyse a sample liquid. In this process a surface can for example be rubbed with the test element. However, the usual field of application for test elements is to analyse sample liquids whereby the sample liquid is either applied to the test element (especially for determinations from blood, serum, liquor) or the test element is dipped into the sample liquid (in particular urine).
Most test elements have to be protected against moisture to avoid reagent decomposition. This applies equally to so-called optical test strips in which a colour change is caused by reaction of an analyte with the sample and also to so-called sensor elements in which a chemical change of the test element caused by the sample is evaluated electrochemically. In addition it is usually necessary to protect test elements from mechanical influences and contamination in order to ensure reliable analytical results. Several types of test element storage methods are known in the prior art. In the first procedure loose test elements are present in a container such as a tube which can be sealed by a stopper or such like. It is also known that test elements can be sealed individually in water-vapour tight foils. However, with the said storage methods it is difficult to remove the test elements mechanically from the storage container or the sealing foil. A number of magazines are known in the prior art in connection with a mechanical removal of test elements as described for example in the patents U.S. Pat. Nos. 5,102,624, 5,154,889, 3,918,910, 4,911,344 and 4,142,863. In this type of magazine test elements are used which are stacked on top of one another. The test elements described in these US patents are specially adapted for use in a magazine i.e. they have a uniform thickness and can be moved relative to one another without getting caught on one another or jamming. However, the majority of commercial test elements do not have a uniform height profile and can therefore not be easily used in magazines of the prior art. A magazine is described in the specification U.S. Pat. No. 3,918,910 which is suitable for storing test elements in which several detection zones are mounted on a support. For manufacturing reasons the detection zones project over the support and thus cause a varying vertical structure of the test element. In FIGS. 5, 6, 7, 9 and 22 of U.S. Pat. No. 3,918,910 a magazine is shown which is suitable for storing such test elements. In this magazine the test elements are stacked on top of one another in such a way that the upper side and underside of successive test elements face one another. The stack of test elements is pressed by spring elements towards a region from where a test element is removed by being pushed or pulled out. Experimental investigations have shown that such magazines are very prone to malfunction. Failures occur frequently in which none of the test elements can be securely gripped by the withdrawal unit or two test elements are erroneously simultaneously transported from the magazine.
Devices are also known in the prior art for separating test strips which can be used to remove individual strips from a disordered quantity of test strips. Such a device is described for example in EP-A-0 255 675. Another separating device is disclosed in U.S. Pat. No. 5,298,425 which also describes a correction of the position of the individual test elements. Experience has shown that devices of this type are very susceptible to break down especially when the test elements are bent.
The object of the present invention was to provide a magazine which operates reliably with the widely used commercial test elements with an uneven height profile. An additional object of the present invention was to provide a magazine which enables a mechanical removal and a high packing density of the test elements.
An additional object of the present invention was to propose a system which enables an automated dispensing of test elements by interaction of a magazine and a removal device. In particular an object of the invention was to reduce the susceptibility to malfunction of known devices of the prior art for separating test elements.
The object is achieved by a magazine for storing test elements which has at least one pair of opposite guide grooves into which the test elements are inserted so that they lie directly adjacent to one another and the edges of adjacent test elements abut one another.
The present invention also concerns a system for dispensing test elements having a magazine with at least two opposite guide grooves into which the test elements are inserted so that they adjoin one another in one plane and the edges of adjacent test elements abut one another and containing a slide one end of which engages the layer formed by the test elements and moves the test elements along the grooves towards the opposite end of the layer.
Within the scope of the present invention it was found that the problems associated with a magazine according to U.S. Pat. No. 3,918,910 are mainly due to tilting of the test elements. With reference to FIG. 5 of U.S. Pat. No. 3,918,910 (see
FIG. 6
of this application) this means that the test elements get into a sloping position relative to the plate (61) or even the plate (61) itself can become lop-sided. This problem was observed in particular when the various test zones of an individual test element have a different height which is frequently the case for commercial test elements with several detection zones. It was also found that the flexibility of the test elements allows bending or even twisting of the test elements so that it is difficult to securely grasp such a test element with a mechanical device. The present invention therefore proposes a magazine in which the test elements are guided in guide grooves and are arranged such that the edges of adjacent test elements directly abut one another. The present invention utilizes the fact that as a result of their manufacture the test elements have an accurately defined width which is constant over the length of the test strip. If, as intended by the invention, both ends of the test elements are guided in grooves and the test elements are arranged next to one another instead of above one another as in the prior art, then as a rule the test elements, but at least the two ends of the test elements, can be definitely positioned. Accordingly the present invention allows a reliable mechanical removal of test elements from the magazine. In particular the magazine of the present invention is suitable for storing test elements which are flexible and/or have an irregular height profile. The present application additionally describes a system which enables test elements to be removed from the magazine according to the invention.
Commercial test elements are shown in
FIGS. 1A and 1B
of the present application.
FIG. 1A
shows a top-view of a test element. The test element (
1
) has a support (
2
) on which several test zones (
3
) are applied. The rectangular test element shown has a shorter side which is named width in the following and a longer side which is named length.
FIG. 1B
shows a side-view of a test element. The different heights of the test zones (
3
) and a bending of the test element can be clearly seen. The bending of the test element can be due to the properties of the support (
2
) as well as due to the manner in which the test zones (
3
) are applied. In a particularly advantageous manufacturing method for test elements, the test zones are mounted on the support and subsequently covered with a fine net. T
Bär Reinhard
Bottwein Gunter
Heid Friedrich
List Hans
Fortuna Ana
Knauer Richard T.
Roche Diagnostics Corporation
Roche Diagnostics GmbH
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