Background and Summary of the Invention
This invention relates to testing apparatus, and more particularly, a device for extracting toxic substances from a specimen, such as paperboard, so as to accurately determine the level of the toxicity present in the specimen.
With the advent of Federal regulations requiring that the level of potentially toxic substances in cardboard or paperboard food containers be held below certain minimum levels, it has become necessary to test such materials in order to be able to determine whether any potentially toxic substances exist in the paperboard or cardboard and if so, to what degree they do exist, as they must be held below certain predescribed limits. In order to accomplish this purpose, it was necessary to develop apparatus for testing for toxic substances which may be present in cardboard or paperboard samples formed into food containers. This invention relates to such an apparatus.
In accordance with the present invention, a toxic substance extraction cell is provided consisting of a chamber for housing a heated solvent, a pair of gaskets adapted to be seated on the solvent housing between which is clamped the specimen to be tested; the space between the gaskets being liquid tight, and a cover for clamping the gaskets to the solvent housing. After assembly of the cell with the preheated solvent in the housing and the specimen to be tested between the gaskets, the cell is inverted and supported on a plurality of legs provided on the cover. The solvent is thus placed in contact with the specimen in order to dissolve any toxic substances contained within the specimen.
The cell is then reinverted and supported on a suitable stand and allowed to cool, by placing the cell for example, in a water bath. The cell is then disassembled and the solvent removed and tested for toxic residue.
Brief Description of the Drawing
Further objects and advantages of the invention will become more apparent from the following description and claims, and from the accompanying drawing, wherein:
FIG. 1 is an exploded perspective view of the extraction cell of the present invention;
FIG. 2 is a longitudinal cross-sectional view of the assembled components of the extraction cell of FIG. 1 and further illustrating the initial step involved in using the cell;
FIG. 3 is a front view in elevation of the cell of FIG. 1 with portions broken away and illustrated in section, which cell has been inverted to enable the solvent to contact the specimen being tested and clamped within the cell; and
FIG. 4 is a view similar to FIG. 3, but with the cell reinverted and being cooled in a water bath.
Detailed Description of the Preferred Embodiment
Referring now to the drawing in detail, wherein like numerals indicate like elements throughout the several views, the components of the extraction cell of the present invention is illustrated in general in FIG. 1 by the numeral 10.
The extraction cell 10 includes a cylindrical solvent housing 12 having a larger diameter circular flange 14 provided along its outer circumference with a plurality of upright pins 16 threadedly engaged in the flange 14. The opposite end of each of the pins 16 is also threaded as indicated at 18.
A pair of Teflon gaskets 20 and 22 which are also circular in configuration are provided. Each of the gaskets includes a plurality of holes 24 about its outer circumference adapted to receive one of the pins 16 therethrough. The gasket 22 includes a circular opening 26 corresponding to the dimensions of the opening 28 in the solvent housing 12 and when the gaskets are placed over the pins 16, the openings 26 and 28 are placed in corresponding registration.
A cover element 30 of the same dimensions as the flange 14 is provided. The cover element 30 also includes a plurality of openings 32 about its outer circumference, each of which is also adapted to receive one of the pins 16 therethrough. A plurality of nuts 35 are adapted to be received on the outer threaded ends 18 of each of the rods 16 to clamp the cover and gaskets to the solvent housing 12 and form a liquid seal along the outer periphery of the clamped elements.
Four upstanding studs 34, 36, 38 and 40 are provided on the exposed surface of cover element 30. The studs 36 and 40 are connected by a radially extending bar 41 so that the bar 41 and studs 36, 40 can provide a handle for grasping and removing the cover from the extraction cell. The studs 34, 36, 38 and 40 also perform the function of providing support legs for the cell when it is inverted as described below.
In use, a suitable circular specimen S from a piece of cardboard or paperboard to be tested is removed and placed between the gaskets 20 and 22 over the opening 26. A suitable preheated solvent T is placed within the housing 12 through the opening 28. The gaskets 20 and 22 are then placed in registration with the rods 16 and the cover applied over the gaskets and the nuts 42 tightened so that the cover 30, gaskets 20, 22, specimen S, and solvent housing 12 are clamped together as a unit and threadedly connected to a standard 42 on a support base 44. The cell 10 is then placed in an upright condition in an oven and reheated, as illustrated in FIG. 2.
After a predetermined temperature has been reached, the cell is then inverted and supported upon the stud legs 34, 36, 38 and 40 provided on the exterior surface of the cover 30, as shown in FIG. 3. The solvent T within the housing 12 will come in contact with the specimen S overlying the registered openings 26 and 28 to dissolve any toxic substances being tested for which may be present in the specimen.
The cell 10 is then reinverted as shown in FIG. 4 and the solvent is allowed to cool by placing the cell in a water bath W. Then the cell 10 is opened by removing the nuts 35 and disassembing the components of the cell, and the solvent evaporated and tested for toxic residue.