Patent Search


Desiccant system


A desiccant system in which a body of water-vapor-adsorbing desiccant material is sealed in a bag which is permeable to water vapor, but not to liquid water or particulates. A humidity indicator is sealed to the bag, and is sensitive to humidity within the bag, but not to water or water vapor outside the bag. The indicator changes color when a predetermined humidity level has been reached within the bag, and thereby to signal that the bag should be replaced.


What is claimed is:

1. A desiccant system, comprising a bag made of a material which is permeable to water vapor, and impermeable to liquid water and particulates, a desiccant material sealed in the bag, and a humidity indicator secured to the bag to sense humidity within the bag, and to be insensitive to water vapor outside the bag.

2. The system defined in claim 1 in which the humidity indicator changes color to signal when a predetermined humidity within the bag has been reached.

3. The system defined in claim 2 in which the humidity indicator is cobalt chloride.

4. The system defined in claim 1 in which the material of which the bag is made is a spun-bonded polyolefin sheet material.

5. The system defined in claim 1 in which the desiccant material comprises a mixture of calcium chloride, Montmorillonite clay, and diatomacious earth.

6. The system defined in claim 5 and in which the desiccant material further comprises scented plastic beads.

7. The system defined in any of the preceding claims, in which the humidity indicator is secured to an outer surface of the bag.



This invention relates to a desiccant bag for adsorbing water vapor from a surrounding space, and having an integrated humidity indicating card which changes color when the adsorption capacity of the bag reaches a level where the bag should be discarded and replaced. The bag finds particular utility in adsorbing water vapor from spaces such as boat cabins and storage areas, stored automobiles, closets, drawers and other home spaces, and storage areas in a seaside location which are especially susceptible to high humidity and damage-causing condensed water.


The desiccant system of this invention comprises a desiccant material sealed in a bag made of a material, preferably spun-bonded polyolefin sheet material, which is permeable to water vapor, and impermeable to liquid water and particulates. A humidity indicator secured to an outer surface of the bag senses the humidity level within the bag, and signals, preferably by a color change, when the adsorbing ability of the desiccant material is exhausted and the moisture-adsorbing desiccant system should be discarded and replaced. The desiccant material may include pleasantly scented plastic beads.


FIG. 1 is a front elevation of a desiccant bag according to the invention; and

FIG. 2 is a sectional view on line 2--2 of FIG. 1 and additionally showing a foil container for storing the bag until it is to be used.


Referring to the drawings, a desiccant bag 10 is made of a porous material which is permeable to, and will pass water vapor, but is impervious to liquid water, dust, and other particulates. A preferred plastic sheet material for the bag is a spun-bonded polyolefin marketed by E. I. duPont under the trademark TYVEK.RTM. with a thickness in a range of 2.0 to 9.1 mils, and typically of about 5.3 mils.

A humidity indicator 11 is in the form of a self-adhesive rectangular card which is adhered to an outer surface of the bag. Only the rear surface of the card facing the bag outer surface senses humidity within the bag, and the card front surface is covered with a transparent and impervious plastic sheet to be isolated from the outside environment. Humidity indicators or markers of this type use a humidity-sensing color-change material 13 such as cobalt chloride, and are available from Desiccare, Inc., in Santa Fe Springs, Calif., assignee of the present invention. This material will change color from, for example, blue to pink or red when a specific humidity level (e.g., typically 50% or 60% depending on the application) is reached within the bag. The bag is then discarded, and replaced with a fresh desiccant bag.

The bag is filled with about six to seven ounces (for the illustrated bag size of about 8 to 9 inches high and about 4 to 41/2 inches wide) of a desiccant material 15 of the following presently preferred formulation:

22% calcium chloride

30% Montmorillonite clay.

Balance of diatomacious earth which absorbs water.

About 5 grams of polyethylene pellets entrained with pleasantly scented material such as lemon oil are added to this mixture. Scented plastic beads of the type described above are available from Aroma Tech in Somerville, N.J., and Polyvel in Hammonton, N.J., and in a variety of long-life odorants which lend a pleasant aroma to the space in which the desiccant bag is located.

The bag can be economically assembled and loaded by a known production device called a "form, fill and seal machine." Humidity indicator 11 is adhered to a cut flat sheet of the Tyvek Bag material on a side which will become the bag outer surface. The sheet is then machine folded along its length to form a tube which is heat sealed along a side or back edge. The lower end of the bag is similarly heat sealed, and the bag is then loaded with desiccant material 15 following which the open upper end of the bag is heat sealed to completely enclose the desiccant. For shipment and storage before use, the completed bag is sealed in a foil bag 17 (FIG. 2) to be isolated from the outside environment.

The materials used in the bag and contents are nontoxic, and no disposal problems are presented when the indicator shows desiccant exhaustion. The bag is easily stored, handled, and placed in service, and provides a convenient, effective and economical means for humidity control and prevention of condensate water in storage areas to be protected.

Heater device for desiccant rotor dehumidifier
Desiccant bag with integrated filter and method of making same
Desiccant device and humidity measuring means
Process for the regeneration of a desiccant
Regenerative desiccant bundle
Desiccant dehumidification system
Desiccant structures for OLED displays

PAT. NO. Title
7037393 Method of constructing a desiccant container
7022167 Desiccant dehumidifier hose connector
6973795 HVAC desiccant wheel system and method
6968713 Desiccant cup with integral filter
6967438 Display device with desiccant coating
6843387 Cover for desiccant dispenser
6835953 Desiccant structures for OLED displays
6833668 Electroluminescence display device having a desiccant
6740145 Desiccants and desiccant packages for highly moisture-sensitive electronic devices
6720054 Desiccant system including bottle and desiccant sheet
6716276 Desiccant system
6711907 Desiccant refrigerant dehumidifier systems
6691640 Animal feeder insert with desiccant cavity
6689197 Desiccant composition
6685452 Implantable drug delivery pump with desiccant humidity protection
6623549 Dye wafer retention in a desiccant container
6534571 Desiccant dispersion for rubber compounds
6531197 Desiccant barrier container
6530973 Air desiccant system and method for automotive climate control
6511525 Method and apparatus for extracting water from air using a desiccant
6506233 Desiccant tablets for gas drying
6481222 Desiccant based humidification/dehumidification system
6474098 Integrated condenser-receiver desiccant bag and associated filter cap
6467185 Potted timer and circuit board assembly for use in a regenerative desiccant air dryer
6453576 Control of solids deposition from used desiccant solution

Copyright © 2006 - 2015 Patent Information Search