Gas separation: apparatus – Solid sorbent apparatus – Soluble or deliquescent type
Reexamination Certificate
1999-12-01
2001-08-14
Spitzer, Robert H. (Department: 1724)
Gas separation: apparatus
Solid sorbent apparatus
Soluble or deliquescent type
C096S147000, C055S424000
Reexamination Certificate
active
06273942
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to the field of dehumidification, in particular, to a tubular moisture absorption apparatus provided with a desiccant in an upper chamber. On contact with moisture, the desiccant forms an aqueous solution which is received by a liquid collection chamber in communication with the desiccant chamber and disposed beneath it.
BACKGROUND OF THE INVENTION
The present invention departs from the tubular moisture-absorbing device disclosed in U.S. Pat. No. 5,676,739 (Gustafsson) designed for vertical disposition in, for instance, a closed steel container for transport of humidity-sensitive goods. The device is made of a polymer coated board which provides a required stiffness. Starting from its upper end, it comprises, in a longitudinal direction, a chamber with a moisture-absorbing material, such as calcium chloride, which forms an aqueous solution on contact with humid air. The salt solution is continuously drained into a lower liquid collection chamber provided in the form of a plastic container with which the upper chamber is in communication. The particulate desiccant material is retained in the upper chamber by a sieve means comprising a non-return valve. Contact of the desiccant with ambient air is ensured by a netting element located in front of an opening in the wall of the upper chamber. The netting element is designed to prevent the aqueous solution from leaving the upper chamber through it rather than through the sieve means.
While the moisture-absorbing device of Gustafsson has been shown to function well in industrial practice, there is room for improvement. Manufacture of the device of the '739 patent necessitates folding and longitudinal gluing of a sheet of plastic board to provide a tubular structure, manufacturing and attaching several plastic parts, such as the sieve means and the netting element, to the tubular structure by gluing, and attaching the plastic container forming the lower chamber to the sieve means, etc.
OBJECTS OF THE INVENTION
A main objective of the present invention is to provide an apparatus of the aforementioned kind which is easier and cheaper to manufacture while retaining the advantageous properties of the device of U.S. Pat. No. 5,676,739.
Further objectives of the invention will become evident from the following summary of the invention, the drawings, the description of preferred embodiments, and the claims.
SUMMARY OF THE INVENTION
The moisture absorption apparatus of the invention comprises an elongated flexible plastic tube having sealed upper and lower ends, one or several wall openings disposed in a wall portion adjacent to the upper end portion, a tubular desiccant container holding a deliquescent desiccant and having gas and liquid permeable walls disposed radially inwardly of said one or several wall openings, and spacer means, preferably of tubular shape, interposed between the plastic tube wall and the desiccant container and/or integrated in the desiccant container to prevent liquid formed in the container from leaving the apparatus through the wall openings. It is preferred that the spacer means is incorporated into the desiccant container. The desiccant container of the invention is of a gas and liquid permeable material, such as a woven or a non-woven plastic material. In the context of the present invention, “axial(ly)” refers to the tube axis while “radial(ly)” refers to a direction perpendicular thereto. Since the apparatus of the invention is designed for use in an upright position, the terms “upper” and “lower” are referenced relative to this working position. The apparatus is kept in the working position by, for instance, a wire fastened at an eye provided at the upper end of the plastic tube, and its other end being held at a suitable point of fixation along an inner wall of a steel container or other compartment.
According to a preferred aspect of the invention, a lumen restrictor disposed in-between the upper and lower ends divide the tube into an upper moisture absorption chamber and a lower liquid collecting chamber.
The present invention is based on the concept that the liquid formed in the container by the absorption of humidity by the desiccant should be kept away from the tube wall to prevent accidental spillage through the wall openings. This is accomplished through impeding flow in the radial direction by the spacer means. The spacer means may be separate from the container or integrated into the container's outer (in a radial direction) wall portion. If separate, a flexible hose of a netted plastic material such as, for instance, the tubular plastic devices used for protecting glass bottles from damaging each other, may be interposed between the container and the wall. If integral, a tubular peripheral portion of the container may be shaped or treated to impede radial flow. For instance, the container may be made of a non-woven plastic material, such as polyethylene terephthalate, in such a manner that its inner wall portion is more dense than its peripheral wall portion, that is, the average distance between filaments is smaller in the inner wall portion than in the outer wall portion. Alternatively or additionally, the filaments of the outer wall portion may be chemically treated to make them more hydrophobic or the filaments of the inner wall portion may be chemically treated to make them more hydrophilic, or both, thus using surface tension phenomena to keep the aqueous solution of the desiccant away from the tube wall.
A preferred desiccant is calcium chloride or desiccant mixtures containing calcium chloride, but in principle, all desiccants which become deliquescent on contact with humid air can be used. The aqueous solution of the desiccant flows through the lumen restrictor into the liquid collection chamber. A non-return valve may be arranged at the restrictor but this is not critical for the performance of the apparatus of the invention; its only function is to prevent liquid from flowing back into the upper chamber and out from there in the event the apparatus falls on the container floor if the suspending wire breaks or comes loose.
The lumen restrictor of the invention preferably supports the desiccant container when the apparatus of the invention is in an upright position. In the absence of a lumen restrictor or if so desired, the desiccant container can be fastened, for instance, at the sealed upper end of the plastic tube.
The sealing of the tube ends and/or the provision of the lumen restricting means can be obtained by any appropriate technique, such as heat or microwave welding or gluing.
To prevent moist air from prematurely entering into the apparatus of the invention the wall openings are suitably covered by a removable seal, such as a plastic sheet applied to outside of the wall portion in which the openings are formed using a non-permanent adhesive of appropriate strength.
The upper and lower end sealed portions of the plastic tube are preferably oriented in the same radial direction, that is, as if the tube were sealed while being flattened against a flat surface. If the sealed portions are arranged in this manner, it is preferred for at least some of the wall openings to be disposed in a wall portion aligned between one or both pairs of axially corresponding radial ends of the sealed portions, i.e., the left ends or the right ends of the sealed portions. In this manner, the apparatus of the present invention, when suspended in a working position and resting with ore side against a steel container or similar wall, will align its sealed ends in parallel with the external wall. Plastic tube wall openings disposed in a wall portion axially disposed between corresponding radial ends of the upper and lower plastic tube sealed portions therefore will be unlikely to abut against an external wall. Such abutment would prevent or at least hinder the apparatus of the invention from exerting its beneficial humidity absorption effect.
The invention will now be explained in more detail with reference to the drawings illustrating the pre
Auxilium Jersby Aktiebolag
Ostrolenk Faber Gerb & Soffen, LLP
Spitzer Robert H.
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