US 3357632 A
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Description (OCR text may contain errors)
Dec. 12 1967 c M. STANFORTH SELF-SEALING CONTAINER Filed Sept.
p F Wm 7: 2 5 2 4 a 5L f \1- C J f v z n n a h 4 H n E m m a m M V w United States Patent 3,357,632 SELF-SEALING CONTAINER Charles M. Stanforth, Cincinnati, Ohio, assignor to General Electric Company, a corporation of New York Filed Sept. 26, 1966, Ser. No. 581,806 Claims. (Cl. 22962.5)
ABSTRACT OF THE DISCLOSURE The disclosure shows a container formed by two layers of flexible polyethylene terephthalate sheet material joined together by seamed portions which define an expansible storage chamber and an inlet passageway. The inlet passageway is elongated and defined, at least in part, by a seamed portion of the sheet material which also defines on its opposite side the storage chamber. The container is filled by inserting a tube through the inlet passageway. Pressurized gas from the tube inflates the storage chamber. When the tube is withdrawn, the inlet passageway is self sealing.
The present invention relates to improvements in fluid containers and, more particularly, to improvements in containers for collecting and storing gas samples.
There are many situations where it is desired to collect a gas sample and then carry it to a remotely-located analyzer, such as a gas chromatograph, for an accurate determination of the constituent components thereof. In order that the integrity of the gas sample be preserved between the time of its collection and the analysis thereof, it has become an accepted practice to employ glass, or other similar inert material, containers for collecting or receiving and then storing such gas samples for later analysis. Not only does this involve a relatively large investment in the containers, it also entails a considerable expense in washing or cleaning the containers after each use so that subsequent samples will not be adulterated by traces of the previous sample.
Not only these specialized containers but, in a broader sense, all containers for fluid storage usually require a closure which represents a substantial portion of the container cost. In the case of gas-storing containers, this is a further problem in that it is desirable to have a closure of the so-called self-sealing type, i.e., a closure which automatically seals itself, after a gas sample has been introduced into the container, without requiring manipulation of a cap or valve element to obtain the sealing action.
Accordingly, one object of the invention is to provide an improved and particularly inexpensive fluid container having a closure of the self-sealing type.
Another object of the invention is to provide such a container which is particularly adapted for the collection of gas samples, which containers are capable of preserving the integrity of the gas sample for a substantial, if not indefinite, length of time and which are sufficiently inexpensive that they may be disposed of after a single use at a cost substantially less than the present cost of using glass containers and Washing or cleaning them for reuse.
Containers formed in accordance with the broader aspects of the present invention are characterized by two sheets or layers of flexible sheet material, joined together by seamed portions which define an expansible storage chamber and an inlet thereto. The inlet is elongated and defined, at least in part, by a seamed portion of the sheet material which also defines on its opposite side the storage chamber.
The container may be filled by inserting a tube through the inlet so that pressurized fluid may be introduced into the storage chamber. When the desired volume of fluid has been introduced into the storage chamber, the filling tube may then be retracted. It is a characteristic of the container that, upon retraction of the filling tube, the elongated inlet passageway, which is isolated from the storage chamber by the seamed portions of the sheet material, automatically seals itself.
Particularly for the collection of gas samples, it is de sirable that the sheet material be impervious to all known gaseous elements, at least of the sample. The best known material for this purpose is polyethylene terephthalate. This resinous polymeric material further fulfills other requisite functions of the container in that it is flexible in order that the storage chamber may be expanded as a fluid sample is introduced therein. Further, the material is relatively stiff, and this characteristic is believed to be a contributing factor to the effectiveness of the sealing action which is obtained by the container configuration.
The above and other related objects and features of the invention will be apparent from a reading of the following description of the disclosure found in the accompanying drawing and the novelty thereof pointed out in the appended claims.
In the drawing:
FIGURE 1 is a view of a container embodying the present invention;
FIGURE 2 is a fragmentary perspective view of the container seen in FIGURE 1 after a fluid sample has been introduced therein;
FIGURE 3 is a section, on an enlarged scale, taken on line III-III in FIGURE 2; and
FIGURE 4 is a section, also taken on line III-III in FGURE 2, which illustrates the use of a tube for introduc ing a fluid sample into the container.
Referring now to the drawing, a rectangularly shaped container 2 for receiving and/or storing a fluid mixture and particularly a gaseous mixture is illustrated in FIG- URES 1-4. Specifically, container 2 is comprised of two superposed sheets or layers of material 6 and 8 secured together by a seam 4 which extends around the peripheral marginal edge portions of the layers. Additionally, the layers 6 and 8 are secured together by a seam 14 which is spaced from and generally parallel to a portion of peripheral seam 4. The seams 4 and 14 define an inflatable storage chamber 10 and an inlet passageway 16 having an inlet port 12 and an exit port 18 opening into the chamber 10.
As previously discussed, the present container is especially suited for receiving and storing gaseous samples. Such containers are useful in the performance of analytical tests on gas samples and, particularly, tests on gaseous combustion products. For such tests to be successful, it is important to insure that the integrity of the gas sample composition will be preserved. It is characteristic of many materials otherwise suitable for the layers 6, 8 to be impervious to some constituents of a given gas sample while not to others. Of particular difficulty is obtaining a suitable material which is impervious to hydrogen. Polyethylene terephthalate resin has been found particularly effective and is preferred for purposes of preserving the gas sample integrity. It is also recognized that material thickness can affect perviousness. A thickness of .005 inch has been found effective but thinner or thicker layers could be used.
The seams 4, 14 of the container must effectively seal the layers 6, 8 and may be formed by various methods, including sealingby heat, solvents or adhesives. Normally, it is preferred to use heat sealing because it is the least expensive method. In the case of the preferred material, special sealing techniques known to the art may be required.
To illustrate use of the container, FIGURE 1 shows schematically, a filler tube 20 connected to a source of pressurized fluid. The filler tube 20 is introduced into inlet passageway 16 (see also FIGURE 4) integral to the con- 3 tainer 2, by deflecting the layers 6 and 8 of the container material which comprise the lips of the inlet port 12. In order to facilitate the introduction of the filler tube into the inlet passageway, one of the layers may be offset or notched, as at 22 depicted in both FIGURES 1 and 2. The space between the tube 20 and the walls of the inlet passageway 16 (FIGURE 4) provides a leakage passageway to prevent overpressurization of the chamber 10. After the storage chamber 10 is filled to a desired amount, as shown in FIGURE 2, the filler tube is retracted. The inlet passageway 16 will automatically return to the condition illustrated in FIGURE 3 and seal itself to thereby isolate the sample of gaseous material from the atmosphere.
The self-sealing properties of the passageway 16 are attributable to several factors. First to be noted is that the passageway 16 is elongated and isolated from the storage chamber 10 by the seam 14.
The relative stiffness of the preferred material is believed to contribute to a self-sealing function. Deflection of the sheet material walls 6, 8, defining the inflated chamber 10, apparently constrict the exit port 18 to form the desired sealing action which is supplemented by other contact areas between the layers 6, 8 along the length of the passageway 16. Further, with a relatively stiff material as the preferred polyethylene terephthalate, a ratio of passageway length to width of at least about 10:1 is preferred.
To withdraw the sample from the storage area, an extraction tube (not shown), similar to the tube 20, is inserted through the inlet port 12 and the inlet passageway 16 and the exit port 18. As this is done, the exit port may be manually pinched to minimize escape or contamination of the sample until the extraction is ready to pass through the exit port to withdraw the sample. The container layers 6, 8 may then be pressed against the extraction as it passes through the exit and into the chamber 10. The chamber 10 may then be collapsed to discharge the fluid sample through the extraction tube.
The container thus formed and described above is a relatively inexpensive item. For collection of gas samples, it may be disposed of after a single use at a cost substantially less than the cost of glass containers and their preparation for reuse.
While the embodiment of FIGURES 1 and 2 illustrate a generally rectangularly configured container having an inlet port located in the vicinity of one of its corners, it should be understood that the invention is not limited thereto and that other embodiments are within the present inventive concepts.
Having thus described the invention, what is claimed as novel and desired to be secured by Letters Patent of the United States is:
1. A container for receiving and storing fluids, said container comprising,
two superposed layers of flexible polyethylene terephthalate sheet material joined together by seamed portions defining an inflatable storage chamber and a passageway thereto,
said passageway being defined by elongated, generally parallel, spaced, sea-med portions isolating the inlet itself from internal fluid pressures in said storage chamber,
said passageway having an inlet at one end and an exit opening into said chamber at its opposite end and further being characterized by the sheet material layers defining same being normally contiguous at least substantially throughout its length,
said layers defining said passageway being deflectable for the insertion of a tube to provide communication with said chamber and resilient to a sealing position upon retraction of said tube.
2. A container for receiving and storing fluids as recited in claim 1 wherein each of said layers of polyethylene terephthalate resin is of 5 mil. gage thickness.
3. A container for receiving and storing fluids as recited in claim 1 wherein the ratio of the length of said passageway to its width is approximately 10:1.
4. A container as in claim 1 having a generally rec tangular outline and the seamed portions are formed marginally of the periphery and include a seam extending inwardly from one edge to a point spaced from the seamed portion at the opposite edge, said seam being parallel to and spaced from the seamed portion of the adjacent edge to define the inlet passageway.
5. A container as in claim 4 wherein the polyethylene terephthalate sheet material has a thickness of approximately .005 inch,
the seamed portions are heat sealed,
said passageway has a length to width ratio of approximately 10:1 and,
one of the layers at the passageway inlet is offset to facilitate insertion of a tube therein.
References Cited UNITED STATES PATENTS 2,719,100 9/1955 Banigan 22948 2,998,340 8/1961 Conway et al. 3,142,437 7/1964 Grant et a1 229-68 3,144,976 8/ 1964 Freshour 2297 FOREIGN PATENTS 980,859 1/1965 Great Britain. 580,742 8/ 1958 Italy.
DAVID M. BOCKENEK, Primary Examiner.