WO1994001340A1

WO1994001340A1 - Activated carbon closure vent

Info

Publication number: WO1994001340A1
Application number: PCT/US1993/000312
Authority: WO
Inventors: Christopher J. Lancette; Michael J. Creed; Scott R. Olson; Keith D. Lokkesmoe
Original assignee: Ecolab Inc.
Priority date: 1992-07-14
Filing date: 1993-01-14
Publication date: 1994-01-20
Also published as: AU3472393A

Abstract

A vented closure device (10) is disclosed which is useful in operation with shipping packaged liquids in containers, such as drums (11). The vented closure device (10) incorporates at least one liquid impermeable, gas permeable membrane (20, 25, 32) to prevent leakage of the liquid contents and contains a scrubbing media (26) which acts to prevent the release of undesirable chemical vapors from the shipping container (11) into the atmosphere. The scrubbing media (26) may be an activated carbon absorber.

Description

ACTIVATED CARBON CLOSURE VENT

Field of the Invention This invention relates to the transportation (shipping), warehousing, and storage of liquid compositions. More particularly, the invention relates to venting packaged liquid chemical compositions while preventing the escape of undesirable vapors into the atmosphere. Background of the Invention

Shipping and handling liquid chemical compositions often involves exposure of the packaged chemicals to a wide range of temperatures. As the temperature of the contents of shipping containers fluctuates, the interior pressure in the container may vary widely. This is especially evident when there is a vapor space above the liquid within the container. Indeed, according to the Ideal Gas Law, assuming the vapor volume and molecular quantity of the vapor remains constant, the pressure in the vapor space will vary in direct proportion to temperature changes. Generally, the container is designed to withstand and contain such pressure variations without resort to venting excess pressure to the atmosphere. However, there are some specific products which are too dangerous to store and transport in unvented containers. Therefore, some packaged liquid chemical compositions may be stored and transported in vented containers. Usually, the shipping container closures comprise some form of pressure release vent, generally, some form of a deformable pressure release device. However, these simple pressure release devices often suffer from the drawback of allowing a portion of the liquid contents of the container to escape during pressure release venting. To combat the problems associated with the leakage of the liquid contents, it has been proposed to use gas- liquid separator membranes within the vented closures. Examples of such vented closures include Cistone, U.S. Pat. No. 3,471,051, von Reis et al. , U.S. Pat. No. 4,765,499, and Dubois et al. , U.S. Pat. No. 4,136,796. These references disclose the use of membranes having varying effectiveness at controlling liquid penetration and escape ranging from spun-bonded polyethylene fibers to more advanced gas permeable, liquid impermeable membranes.

While these closure devices represent an advance in the art, they still suffer from a number of drawbacks. The closure devices discussed above make no attempt to prevent the escape of undesirable vapors into the atmosphere during the pressure release venting. As the Environmental Protection Agency (EPA) promulgates more stringent rules regarding the release of organic and other hazardous gases and vapors into the atmosphere, the use of traditional, pressure release closure vents must be reexamined. A now desirable feature in such closure vents is the ability simultaneously to release vapor pressure buildup within a shipping container and to prevent the escape into the atmosphere of undesirable vapors. Further, many of the shipping containers used with packaged liquid chemical compositions are reused. These containers should be reusable without losing their ability to simultaneously release pressure and sequester undesirable vapors. Therefore, a new vented closure system is needed for shipping containers for liquid chemical compositions. These vented closures should be able to simultaneously regulate internal vapor pressure of the container without allowing the escape into the atmosphere of harmful vapors from the interior of the container. Finally, these vented closures should be reusable or rechargeable to provide for numerous use cycles of both the container and the vented closure assembly.

Summary of the Invention A venting closure device can be manufactured to address the shortcomings of the prior art. In particular, a venting closure device can be prepared from a closure for a shipping container and a venting device operatively connected to the closure. The venting device can be made from a gas permeable, liquid impermeable membrane and a vapor scrubbing media disposed within the venting means. The membrane and the closure cooperatively prevent the passage of liquid from the interior to the exterior of the container, and vapors leaving the interior of the container pass through the membrane and vapor scrubbing media prior to their escape into the atmosphere. The venting closure device may be arranged and configured to substantially lie within or outside of the shipping container when installed. This device may be used with shipping containers for packaged liquids, containers having a capacity of less than about 2,000 liters (L) .

The phrase "undesirable vapors" as used here in the specification and the claims is intended to include organic and inorganic gases and vapors which are corrosive, toxic, odorous, flammable or explosive, reactive, hazardous, and the like.

In addition, the term "vapor" as used here in the specification and the claims includes that matter which exists in the vapor state or which may be carried in the gaseous phase of a multiphase mixture. Representative, non-limiting examples of such matter includes vapors evaporated from a liquid, aerosols, gases dissolved or entrained in a product and the like.

Brief Description of the Drawings FIGURE 1 is a perspective view of one embodiment of the vented closure device fitted on a drum for the transport of liquid chemical compositions.

FIGURE 2 is a partially cut-away frontal view of the vented closure device of Fig. 1 in exploded form.

FIGURE 3 is a partially cut-away frontal view of a vented closure device which is primarily contained within the shipping container.

FIGURE 4 is a partially cut-away frontal view of a vented closure device which is predominantly contained within a shipping container.

Detailed Description of the Drawings Referring to Fig. 1, the vented closure device 10 of the present invention is designed for use with shipping containers such as a drum 11. When the drum 11 is charged with a liquid chemical composition, there is generally a vapor space lying above the liquid level within the drum 11. With increasing temperature, the vapor pressure tends to increase within the confines of the drum 11. As the vapor pressure builds up within the drum 11, vapors may be released through the vented closure device 10. To prevent the release of undesirable vapors, the escaping vapors are cleaned by passage through a scrubbing media contained within a rechargeable canister 12. The term "cleaned" as used here in the specification and in the claims, is meant to encompass the general concept of rendering the vapors less objectionable by neutralizing, sequestering, removing, etc., undesirable vapors from the escaping vapors. The cleaned vapors 13 are then permitted to escape into the atmosphere. The canister 12 may be removably attached to a threaded closure 14 which sealingly engages a fill aperture in the shipping container 11.

Referring now to Fig. 2, the vented closure device 10 is shown in greater detail. In the embodiment of the invention illustrated in Fig. 2, the vented closure device 10 comprises a scrubbing canister 12, a canister cover 15, and a threaded closure 14.

The threaded closure 14 has outer threads 16 for engaging the threaded aperture of the shipping container (e.g., 11 in Fig. 1), inner threads 17 for engaging a threaded connecting portion of the canister 12, and a bottom plate 18 having an aperture 19 which is covered by a membrane 20. When sealingly engaging the threaded aperture of the shipping container 11, the threaded closure 14, bottom plate 18, and membrane 20 provide a barrier to prevent the escape of liquids from the shipping container 11. However, the membrane covered aperture 19 in the threaded closure 14 nonetheless provides a path for the escape of vapors 21 from the interior of the shipping container 11.

The scrubbing canister 12 has a threaded connecting portion 22 which may be welded, crimped, screwed, or otherwise attached to or formed integrally with the canister 12. This connecting portion 22 provides a conduit for vapors 21 leaving the interior of the shipping container 11. The base 23 of the canister 12 is provided with an aperture 24 sealingly covered by a membrane 25. Again, this membrane 25 is liquid impermeable and vapor permeable. This aperture/membrane arrangement provides a backup to that in the threaded closure 14 to prevent the leakage of liquid from the shipping container 11 and also contains a quantity of a scrubbing media 26. The scrubbing media 26 absorbs, sequesters, reacts with, or otherwise purifies

(hereinafter generally termed "purifies") the vapors 21 leaving the interior of the shipping container 11 and traveling through the scrubbing media 26 toward the outside atmosphere. Canister 12 is closed by means of a canister cover 15 having threads 27 for sealingly engaging threads 28 in the canister 12. In addition, there is a gasket 29 which fits in a groove 30 along the top rim of canister 12. Finally, the cover 15 also has an aperture 31 and a membrane 32 to prevent the escape of the scrubbing media 26 and as a final backup to prevent the escape of the liquid content of the shipping container 11. Purified and scrubbed vapors 13 may then escape through this aperture 31 and membrane 32 into the atmosphere to relieve excess pressure within the shipping container 11.

In a second embodiment, illustrated in Fig. 3, the vented closure device (similar to 10 of Fig. 1) of the present invention is designed to project into the interior of a shipping container (similar to 11 of Fig. 1) . This embodiment comprises a scrubbing canister 50 having an outer perforated wall 51 providing a plurality of apertures 52 for conducting vapors 53 away from the interior of a shipping container. Within the confines of the outer perforated wall 51 is a smaller cylindrical canister 54. This canister 54 is arranged and configured to contain a quantity of scrubbing media 55. A conduit 56 extends from a charging region of the scrubbing media 55 near the bottom inside portion of the interior canister 54 through an aperture 57 to an annular space 58 between the interior canister 54 and the perforated wall 51. The outer terminus of the conduit 56 is covered with a liquid impermeable, vapor permeable membrane 59.

The conduit 56 provides a passage for vapor 53 from the interior of the shipping container via the annular space 58 through the membrane 59 to the charging region of the inner canister 54. At this point, the vapors 53 contact the scrubbing media 55 to begin the "purification" of the vapors 53. The vapors ultimately exit a discharge region at the upper surface 60 of the scrubbing media 55. The "purified" vapors leaving the surface 60 are essentially free of the undesirable vapors 61.

The interior canister 54 is sealingly connected to a threaded shipping container closure 62 and is enclosed by means of a top cover 63. The top cover 63 engages the container closure 62 by means of a threaded mating. A portion of the top cover 63 is provided with an aperture 64 sealed by a membrane 65 which defines an outlet passage for the "purified" vapors 61. The container closure 62 is configured and arranged to sealingly engage a threaded aperture in a shipping container. In a third embodiment, illustrated in Fig. 4, the vented closure device 70 (similar to 50 of Fig. 3) of present invention is designed to project into the interior of a shipping container (similar to 11 of Fig. 1). This embodiment comprises a scrubbing canister 71 which is welded, crimped, screwed, integrally formed with, or otherwise connected to a threaded shipping container closure 78 and is enclosed by means of a top cover 79. The top cover 79 engages the container closure 78 by means of mating threads 80 of the cover 79 to threads 77 of the container closure 78. A portion of the top cover 79 is provided with an aperture 81, which may or may not be sealed by a membrane 82, which defines an outlet passage for the "purified" and scrubbed gases 83 to escape the canister 71. The container closure 78 has outer threads 76 for sealingly engaging the threaded aperture of the shipping container (e.g., 11 in fig. 1), thus preventing the escape of liquids from the shipping container 11. The bottom of the scrubbing canister 71 has an aperture 72 which is sealingly covered by a membrane 73. Again, this membrane 73 is liquid impermeable and vapor permeable. The membrane covered aperture 72 provides a path for the escape of vapors 74 from the interior of the shipping container 11, while preventing the liquid contained in the shipping container 11 from escaping into the canister 71. Canister 71 contains a quantity of scrubbing media 75 which adsorbs, sequesters, reacts with, or otherwise purifies the vapors 74 leaving the interior of the shipping container 11 and traveling through the scrubbing media 75 toward the outside atmosphere.

The vented closure device as described herein is useful for venting shipping containers for packaged liquid chemical compositions. These containers generally range from about 1 to about 2,000 L, preferably about 20 to 200 L. Standard container sizes include five gallon pails (about 20 L) and 55 gallon drums (about 200 L) .

These containers may be used for shipping liquid chemical compositions which contain or are capable of generating undesirable vapors. Often, these compositions include organic, caustic, and acidic compounds. The generation of vapors from such compositions may be undesirable due to the vapors' corrosiveness, toxicity, odor, flammability or explosiveness, reactivity, etc.

In order to prevent the escape of these compounds in a vapor state, the vented closure device contains a scrubbing media. As used herein in the specification and in the claims, the term "scrubbing media" is intended to encompass those materials which are capable of immobilizing, neutralizing, etc. organic or other undesirable vapors to prevent their escape into the atmosphere. Useful means for removing these undesirable vapors include absorbers, and chemically reactive compounds. A representative, non-limiting list of useful absorbers includes activated carbon and sodium carbonate. Reactive compounds may be chosen to selectively react with and neutralize or immobilize the undesirable vapors known to be in the contained liquids. A representative, non-limiting list chemically reactive compounds includes carbonate salts, phosphate salts, calcium hydroxide, sodium sulfate, sodium bisulfate, etc.

The vented closures are designed to permit the recharging of the scrubbing media within the canisters. Further, these canisters can be proportioned to provide a volume of scrubbing media necessary to effectively prevent the escape of undesirable vapors into the atmosphere during the period of time between shipping and ultimate consumption of the chemical compositions contained within the shipping containers. Of course, this volume will vary depending upon the volatility of the undesirable components within the composition, the temperatures expected to be encountered by the shipping container, and the volume contained by the shipping container itself. An additional factor which is to be considered is the length of time needed for the scrubbing media to be effective.

The liquid impermeable, gas permeable membrane may be of any configuration which provides pores smaller than necessary to allow penetration of the membrane by liquids under pressures normally seen in the shipping and warehousing environments. In addition, the membrane should be resistant or inert to attack by the chemical compounds and compositions contained within the shipping container. A representative, non-limiting list of useful membrane materials includes polytetrafluoroethylene such as GORETEX ®, fluorocarbon filaments, polyolefins such as polyethylene and polypropylene, polysulfone, polynitrile, and polysytrene. The venting closure device may be formed of any suitable material including metals, plastics, ceramics and glass, etc. The components of the device may be joined by any means such as welds (including ultrasonic), crimps, cement and other adhesives, mechanical fasteners, etc., or the components may be formed as a unit.

The venting closure device sealingly engages the charging aperture of the shipping container using any suitable means. The closure device may engage in a threaded fashion, through a deformable snap-locking closure, through a quick-release twisting engagement, or a clamping engagement.

Examples The following Examples are intended to illustrate the above invention and should not be construed as to narrow its scope. One skilled in the art will readily recognize that these Examples suggest many other ways in which the present invention could be practiced. It should be understood that many variations and modifications may be made while remaining within the scope of the invention. Example 1

A test was conducted on two drums, 4 replications each, at 73°F. Each drum contained 50 gallons of an oxidizing solution consisting of approximately 8% acetic acid, 5.2% peracetic acid, and 25% hydrogen peroxide. all in aqueous.

Each drum was fitted with a tube. One end of the tube was attached to the drum vented closure and sealed, and the other end was placed into 100 mL of 0.1N aqueous caustic solution (NaOH) . The solution trapped the vapors by neutralizing them. The vapors were allowed to bubble through the solution for 4 hours. A 10 mL sample from the solution was titrated using hydrochloric acid and found to contain an average of 9.8 mg of acetic acid for drum #1, and an average of 9.2 mg of acetic acid for drum #2 (see table below). This equates to an overall average rate of 9.5 mg of acetic acid vapors per hour. These data illustrate that the gases released from the drums contained acetic acid.

Three drums containing 50 gallons of an aqueous oxidizing solution consisting of approximately 8% Acetic Acid, 5.2% Peracetic acid, and 25% Hydrogen Peroxide at 73°F were fitted with closures and canisters (as illustrated in Fig. 2). Each canister contained 39.6 g, 39.8g, and 39.9 g of activated carbon pellets respectively. As a control, a fourth drum was fitted with a canister which did not contain carbon pellets or other odor absorbing media. Each day the drums were checked for odors by smell. (Two different people checked the drums each day for odors as a means of addressing each individuals odor sensitivity) . Odors were first sensed at 32 days from drum number 1, 33 days for drum number 3, and 35 days for drum number 2. In addition, the carbon increased in mass by the following: Drum #1: +4.0g. Drum #2: +4.5g, and Drum #3: +4.1g, indicating an absorption of odorous gases. Odors were detected on drum #4 (control) within the first hour of test commencement. This example illustrates that the canister with activated carbon absorbs odors from organic vapors. Other modifications of the invention will be apparent to those skilled in the art in light of the foregoing description. This description is intended to provide specific examples of individual embodiments which clearly disclose the present invention. Accordingly, the invention is not limited to these embodiments or the use of elements having specific configurations and shapes as presented herein. All alternative modifications and variations of the invention which follow in the spirit and broad scope of the appended claims are included.

Claims

WHAT IS CLAIMED IS:

1. A device (10) for closing a shipping container

(11) having a capacity of less than about 2,000 L and defining an interior and an aperture for charging and dispensing liquids therefrom, which device (10) provides for venting excess vapor pressure, prevents leakage of liquids from the container, and comprises:

(a) means (14) for sealingly engaging the aperture; and

(b) venting means (12) operatively connected to the means for sealingly engaging the aperture, which venting means comprises:

(i) a gas permeable, liquid impermeable membrane (25) having a liquid side and a vapor side wherein vapors (21) leaving the interior of the container pass through the liquid side of the membrane (25) before passing through the vapor side thereof; and (ϋ) means (26) for removing undesirable vapors from a gas adjacent the vapor side of the membrane (25); wherein the membrane (25) and means (14) for sealingly engaging the aperture cooperatively prevent the passage of liquids through the aperture of the container (11) and vapors leaving the interior of the container pass through the membrane (25) and means (26) for removing undesirable vapors prior to escape into the atmosphere.

2. The device of claim 1 wherein the venting means (12) is arranged and configured to be substantially contained within the shipping container (11).

3. The device of claim 1 wherein the venting means

(12) is arranged and configured to be substantially located outside of the shipping container (11).

4. The device of claim 1 wherein the gas permeable, liquid impermeable membrane (25) comprises a polytetrafluoroethylene membrane.

5. An article for the transport of liquids which comprises:

(a) a shipping container (11) having a capacity of less than about 2,000 L, which container (11) is impermeable to liquids and defines an interior and an aperture for charging and dispensing liquids therefrom;

(b) means (14) for sealingly engaging the aperture; and (c) venting means (12) operatively connected to the means (14) for sealingly engaging the aperture, which venting means (12) comprises:

(i) a gas permeable, liquid impermeable membrane (25) having a liquid side and a vapor side wherein vapors leaving the interior of the container (11) pass through the liquid side of the membrane (25) before passing through the vapor side thereof; and

(ii) means (26) for removing undesirable vapors from a gas adjacent the vapor side of the membrane (25); wherein the membrane (25) and means (24) for sealingly engaging the aperture cooperatively prevent the passage of liquids through the aperture of the container (11) and vapors leaving the interior of the container (11) pass through the membrane (25) and means (26) for removing undesirable vapors prior to escape into the atmosphere.

6. The article of claim 5 for the transport of liquids which comprises:

(a) a shipping container (11) having a capacity of less than about 500 L, which container (11) is impermeable to liquids and defines an interior and an aperture for charging and dispensing liquids therefrom;

(i) a gas permeable, liquid impermeable polytetrafluoroethylene membrane (25) having a liquid side and a vapor side wherein vapors leaving the interior of the container (11) pass through the liquid side of the membrane (25) before passing through the vapor side thereof; and

(ii) an effective amount of activated carbon (26) for removing undesirable vapors from a gas adjacent the vapor side of the membrane (25); wherein the membrane (25) and means (14) for sealingly engaging the aperture cooperatively prevent the passage of liquids through the aperture of the container (11) and vapors leaving the interior of the container (11) pass through the membrane (25) and activated carbon (26) prior to escape into the atmosphere.

7. The device of claim 1 for closing a shipping container (11) defining an interior and an aperture for charging and dispensing liquids therefrom and having a capacity of less than about 2,000 L, which device comprises:

(a) means (62) for sealingly engaging the aperture; and

(b) venting means (50) operatively connected to the means (62) for sealingly engaging the aperture extending into the interior of the container (11), which venting means (50) comprises: (i) a gas permeable, liquid impermeable membrane (59) having an interior and an exterior side wherein vapors leaving the interior of the container (11) pass through the interior side of the membrane (59) before passing through the exterior side thereof; (ii) removable means (55) for removing undesirable vapors from a gas having a charging region and a discharge region (60) which is disposed within the venting means (50); (ϋi) means (56) to conduct vapors leaving the interior of the container (11) from the interior side of the membrane (59) to the charging region of the means (55) for removing undesirable vapors; and (iv) means (64, 65) to conduct vapors from the discharge region (60) of the means (55) for removing undesirable vapors to the exterior of the container (11); wherein the membrane (59) and means (62) for sealingly engaging the aperture cooperatively prevent the passage of liquids through the aperture of the container (11) and vapors (53) leaving the interior of the container (11) pass through the membrane (59) and means (55) for removing undesirable vapors prior to escape into the atmosphere.