US3140796A - Planchet - Google Patents

Description

July 14, 1964 BRQIDA 3,140,796

PLANCHET Filed Aug. 22, 1962 F|G 3 I 1 23 r 36 i 2 FIG 2 7 5 is I [f I x I I W I IN VEN TOR IflN/A-Z Eff/F4 i7?" rmers,

United States Patent 3,140,796 PLANCHET Daniel Broida, Ladue, M0., assignor to Sigma Chemical Company, a corporation of Missouri Filed Aug. 22, 1962, Ser. No. 218,615 2 Claims. (Cl. 220-66) This invention relates to planchets, particularly for use for radioassays.

Planchets for radioassays are of two main varieties, fiat and cupped. The cupped type has a bottom surrounded by a circumferential rim. This invention is more particularly directed to the cupped type. Commercially, the cupped planchets are available in smoothbottomed and concentric ring bottomed types. The bottom surface of the latter type is embossed to form, on the inner side, a series of concentric radially spaced annular ridges. This provides, in effect, a plurality of radially spaced shallow annular troughs, each bounded by uninterrupted dikes, so that materials, particularly liquids, which are placed in the planchet, are inhibited from creeping radially across the bottom.

One of the objects of this invention is to provide a planchet in which uniform distribution of materials is encouraged.

Another object is to provide planchets of the concentric ring bottom type in which uniform circumferential distribution is encouraged.

Still other objects will become apparent to those skilled in the art in the light of the following description and accompanying drawing.

In accordance with this invention, generally stated, a planchet is provided, with a plurality of concentric, annularly raised ridges in its bottom, and with a plurality of radially extending, symmetrically arranged ribs, lower in profile than the annularly extending ridges.

The radially extending ribs serve, in addition to making the bottom more rigid, to promote the uniform distribution of materials, around the bottom of the planchet. To this end, the disparity in height between the annular ridges and the radial ribs is significant. If the radial ribs were as high as the annular ridges, there would be danger of segregating material in one of the areas defined between two successive ribs.

In the drawing, FIGURE 1 is a top plan view of one embodiment of planchet of this invention;

FIGURE 2 is a much enlarged sectional view taken along the line 22 of FIGURE 1; and

FIGURE 3 is a top plan view of another embodiment of planchet of this invention.

Referring now to FIGURES 1 and 2 of the drawing for one illustrative embodiment of this invention, reference numeral 1 indicates a completed planchet. The planchet 1 has a flat bottom 2, upstanding circumferential rim 3, four concentric annular ridges 4, 5, 6 and 7, in order from the center, and four radially extending, symmetrically arranged ribs 8, 9, and 11.

The annular ridge 4 defines within its compass a flatbottomed basin 14, and with the ridge 5, an annular flatbottomed channel 15. The ridge 5, defines with the ridge 6, an annular flat-bottomed channel 16. The ridges 6 and 7 define between them an annular flat-bottomed channel 17, and the ridge 7 and the rim 3 define between them an outer annular channel 18.

It can be seen that, in the embodiment shown, the basin 14 and the outer annular channel 18 are uninterrupted by the ribs 8-11. It can also be seen, particularly in FIGURE 2, that the ribs 8-11 are shallower than the ridges 47. The small area of the basin 14 makes distribution of the material within it of less importance that its distribution through the channels 15- 3,140,796 Patented July 14, 1964 17 and the absence of the ribs within the basin avoids channeling into one quadrant of material introduced to the basin. As has been explained heretofore, the shallowness of the radially extending ribs, as compared with the annular ridges, permits material to be distributed throughout a channel, before the material overflows to the next outer channel. At the same time, if the level of the material decreases, as with the evaporation of liquid or sublimation of solids, the amount of material dammed by and between the radial ribs, will remain thus distributed throughout the channel.

Preferably material is introduced into the basin 14, and spills outwardly into successively radially outer channels. The outermost channel 18 is chiefly an overflow channel, in which excess material is contained. If the planchet is tilted, so as to introduce to the outermost channel an excess of material, the absence of radial ribs permits material to flow promptly to the low spot and thus be returned to the next outermost channel 17.

In the embodiment shown in FIGURE 3, a planchet 26 is illustrated, which has a bottom 22, a circumferential rim 23, only two annular ridges, an inner ridge 24 and an outer ridge 25 concentric therewith, and six radial ribs 26, 27, 28, 29, 30 and 31.

The inner ridge 24 defines a central basin 34. In this embodiment, the outer ridge 25 is positioned in relation to the rim 23 in about the same way as the ridge 7 is positioned with respect to the rim 3 of the embodiment shown in FIGURES 1 and 2. This leaves a wide intermediate channel 35, traversed by the ribs 26-31, and a relatively narrow channel 36 between the ridge 25 and the rim 23. In this embodiment, as in the first embodiment shown and described, the bottoms are flat.

In both embodiments, the ridges are radially narrow as compared with the commercial concentric-ringed planchets known heretofore, leaving wide-r channels, the bottoms of which are flat, as distinguished from the relatively narrow channels which are apparently somewhat concave in cross section in the present crommercial planchets of others. This feature of the present invention also aids the uniform distribution of material at a uniform depth.

The planchets of this invention can be made of any desired materials, such as aluminum, glass, plastic, stainless steel, iron, copper, or the like. The metal planchets may be plated. They are normally designed for throwaway use, but they need not be discarded. They may be made in any desired size, the present commercial planchets being commonly between 1 and 2 inches in diameter. A typical planchet of this invention would be 1 7 inches in diameter, with a rim inch high, ridges .015 inch high, and ribs .006 inch high. The ridges are approximately inch thick, radially, at their inside roots, the channels about & inch wide radially between roots of successive ridges and the basin about inch in diameter. It is to be understood that these specific dimensions are merely illustrative.

Numerous variations, within the scope of the appended claims, will occur to those skilled in the art in the light of the foregoing disclosure. For example, more or fewer ridges and ribs may be employed, and absolute dimensions may be varied, as long as the rim is at least as high as the ridges and the ribs are shallower than the ridges.

Having thus described the invention, what is claimed and desired to be secured by Letters Patent is:

1. In a cupped planchet the improvement comprising a flat bottom having a plurality of concentric annular ridges on its inner surface, and a plurality of radially extending symmetrically positioned ribs on its inner surface, said ribs being of a height less than the height of said annular ridges.

2. In a cupped planchet the improvement comprising a flat bottom having a plurality of concentric annular ridges in its inner surface, the innermost of said ridges defining a central basin in said bottom and the outermost of said ridges defining, with a circumferential rim, an annular outer channel, and a plurality of radially extending, symmetrically positioned ribs on the inner surface of the bottom, said ribs extending between the radially outer side of the innermost ridge and the radially inner side of the outermost ridge, whereby the basin and outer channel are uninterrupted by said ribs, and said ribs being of a height less than the height of said annular ridges.

References Cited in the file of this patent UNITED STATES PATENTS 1,865,742 Chapman July 5, 1932 10 1,970,151 Smith Aug. 14, 1934 2,080,125 Frost May 11, 1937

Claims (1)

1. 2. IN A CUPPED PLANCHET THE IMPROVEMENT COMPRISING A FLAT BOTTOM HAVING A PLURALITY OF CONCENTRIC ANNULAR RIDGES IN ITS INNER SURFACE, THE INNERMOST OF SAID RIDGES DEFINING A CENTRAL BASIN IN SAID BOTTOM AND THE OUTERMOST OF SAID RIDGES DEFINING, WITH A CIRCUMFERENTIAL RIM, AN ANNULAR OUTER CHANNEL, AND A PLURALITY OF RADIALLY EXTENDING, SYMMETRICALLY POSITIONED RIBS ON THE INNER SURFACE OF THE BOTTOM, SAID RIBS EXTENDING BETWEEN THE RADIALLY OUTER SIDE OF THE INNERMOST RIDGE AND THE RADIALLY INNER SIDE OF THE OUTERMOST RIDGE, WHEREBY THE BASIN AND OUTER CHANNEL ARE UNINTERRUPTED BY SAID RIBS, AND SAID RIBS BEING OF A HEIGHT LESS THAN THE HEIGHT OF SAID ANNULAR RIDGES.

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