US 3315447 A
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Description (OCR text may contain errors)
April 25, 1967 v. D. MEIER WATER REPELLANT DEHUMIDIFIER Filed Oct. 23, 1964 FIG. 1
INVENTOR. VINCENT D. MEIER F/GE wxhgveeaw ATTORNEY United States Patent 3,315,447 WATER REPELLANT DEHUMIDIFIER Vincent D. Meier, Port Washington, N.Y., assignor to the Um'ted States of America as represented by the Secretary of the Navy Filed Oct. 23, 1964, Ser. No. 406,205 2 Claims. (Cl. 55384) The present invention relates to a novel and improved container and more particularly to a novel and improved container in which a dehumidified environment may be maintained for prolonged periods of time.
In the preservation of items such as metallic hardware for prolonged storage intervals, it is generally desirable to minimize deterioration of various types including corrosion, mildew, fungus and other microbiological attacks. Inasmuch as the presence of moisture is generally necessary before any such deterioration can begin, various types of packing materials and containers have been devised in the past in an attempt to provide an effective vapor barrier about the item to be protected. Heretofore, however, such attempts to control and dehumidify the environment about the item to be protected in a practical and economically feasible manner have been at best only partially successful.
It is therefore a principal object of the present invention to provide a novel and improved protective package or container within which a dehumidified atmosphere may be maintained for extended periods of time.
It is a further object of the present invention to provide a novel and improved protective package or container which includes a membrane type closure through which gases and moisture vapor pass but through which no larger particles including fungus spores, insects, corrosive dust and water droplets may infiltrate.
It is a further object of the present inveniton to provide a novel and improved protective package or container which includes a membrane type closure that on exposure to radiant solar energy permits the transfer of moisture outwardly from the interior of the package more readily than in the opposite direction.
Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawing wherein:
FIG. 1 of the drawing is a partially cutaway perspective view of a preferred embodiment of the present invention; and
FIG. 2 is a cross-sectional view of the embodiment of the invention shown in FIG. 1 along reference line IIII therein.
A preferred embodiment of the invention is illustrated in FIGS. 1 and 2 of the drawing. As shown therein, a moisture proof container having a closure 3 is indicated at 5. Container 5, which is shown in one suitable form,
is a metallic drum having a cylindrical peripheral wall 7 and a bottom 9. An opening at the top of container 5 for the insertion and removal of its contents is of substantial size and is herein illustrated to extend across the full diameter of the drum. Around the opening in container 5, the peripheral edge of wall 7 is preferably rolled outwardly and downwardly into a hollow bead 11 of circular cross-section.
The closure 3 includes the perforated metallic plate or grid 13 which in its container sealing position extends across the entire opening at the top of container 5 and extends downwardly as at 15 at its outer edge to resiliently engage the bead 11 on container 5. Two flexible permeable membranes 17 and 19 are disposed on opposite sides of plate 13 and are preferably secured to the plate in any 3,315,447 Patented Apr. 25, 1967 suitable manner adjacent its outer downwardly flanged edge. Otherwise, the membranes 17 and 19 are unattached to the plate 13 and generally form pockets that respectively bellow above and below the plate 13. Each pocket on either side of plate 13 is filled with a suitable hygroscopic material 21 such as silica gel or lithium chloride. The outer membrane 17 which forms the pocket above plate 13 is preferably dark in color so as to absorb heat from solar radiant energy in a manner which will be described more fully hereinafter. The inner membrane 19 which extends downwardly beneath plate 13 is preferably transparent or colorless. Otherwise, any suitable plasticized vinyl film which exhibits an increase in porosity with an increase in temperature in a manner which is described more fully hereinafter may be used to form membranes 17 and 19.
In operation, the item to be protected is first placed in container 5 and the closure 3 is resiliently secured over the head 11 on the upper lip of container 5. When during the heat of the day, solor energy penetrates closure 3 and warms the membranes 17 and 19, the desiccant 21, and the atmosphere Within the container, the desiccant 21 tends to discharge moisture into the interior of container 5 as well as the outer atmosphere. However, inasmuch as the temperature of the atmosphere within the container 5 rises more than that of the outside atmosphere, the internal moisture vapor pressure increases more than the moisture vapor pressure outside the container and more moisture from the desiccant 21 is transmitted outwardly into the outer atmosphere than inwardly into the interior of the container. Moreover, inasmuch as membranes 17 and 19 become more porous with an increase in temperature and inasmuch as the outer membrane 17 is dark in color and therefore absorbs more heat from the solar radiant energy than the colorless inner membrane 19, moisture from the desiccant 21 passes more readily into the outer ambient atmosphere than into the interior of container 5.
Later, at the end of the day when the sun goes down and the container 5 and its contents begin to cool, the desiccant 21 tends to reabsorb moisture from the interior of container 5 as well as from the outer atmosphere. The atmosphere within the container generally cools more than the atmosphere outside so that the moisture vapor pressure inside container 5 decreases more than that outside. Therefore, there is a tendency during the cooling interval for the desiccant 21 to absorb more moisture from the outer atmosphere than from the interior of container 5. However, at the same time outer membrane 17 cools faster than inner membrane 19 causing outer membrane 17 to be less porous than inner membrane 19. There is therefore a simultaneous counter tendency of the desiccant to absorb more moisture from the interior of container 5 during the cooling interval. Thus, it will be seen that the net effect of the intermittent exposure of container 5 to solar energy is to maintain a relatively dehumidified atmosphere within container 5 for extended periods of time without a need of replacing the desiccant 21 which otherwise might be expected to become moisture saturated.
Obviously, many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.
What is claimed is:
1. A closure for an enlarged opening in a container, said closure comprising:
(a) a first plasticized vinyl membrane which covers the entire opening and is sealed to the lip of the container that defines the opening;
- e the exterior surface of said first membrane and is also sealed to the lip of the container, said second membrane being dark in color so as to readily absorb heat from radiant solar energy; and
(c) a desiccant disposed between the first and second membranes. 7
2. A closure for an enlarged opening in a container, said closure comprising:
(a) a perforated plate disposed across the opening in the container; 7
(b) a first plasticized vinyl membrane which covers the entire interior surface of the plate;
(0) a second plasticized' vinyl membrane which covers the entire exterior surface of the plate, said second membrane being dark in color so as to readily absorb heat from radiant solar energy; and
(d) a desiccant disposed between the plate and both said membranes.
References Cited by the Examiner UNITED STATES PATENTS Poetschke 55 -3ss X FOREIGN PATENTS Great Britain.
REUBEN FRIEDMAN, Primary Examiner.
J. W. ADEE, Assistant Examiner.