Containment device

Details Containment device Containment device

2001-03-22

2002-07-30

Maust, Timothy L. (Department: 3751)

Fluent material handling, with receiver or receiver coacting mea

With guard or screen for operator

C141S059000, C141S285000, C141S347000, C141S383000

Reexamination Certificate

active

06425423

ABSTRACT:

The benefit of priority is claimed based on UK Patent Application No. 0007024.3 filed on Mar. 23, 2000, the complete disclosure of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a device (e.g., an extraction hood) for localised containment of extraneous powdered material (e.g., powdered pharmaceutical materials) in a material transfer apparatus.
2. Description of the Related Art
In the field of material transfer technology, it is known to transfer material between a material supply means (e.g., a powder bin) and a material receiving means (e.g., a reaction vessel) using a valve-operated device. A number of valve-operated devices are known.
A basic butterfly valve comprises a simple flap (“the butterfly”) which is rotatable about an axis to increase or decrease the cross-sectional area of an aperture whereby to control the material flow rate between material supply means and material receiving means. The basic butterfly valve is appropriate for a fixed processing arrangement but is unsatisfactory for transfer between discrete material supply means and material receiving means. This has led to the development of the split butterfly valve in which the valve is split through the butterfly in a direction perpendicular to its longitudinal axis. Thus, the split butterfly valve comprises two discrete parts, a first part secured to the material supply means and a second part secured to the material receiving means, each of which permits containment of material in a material supply means or a material receiving means to which the respective part is secured. In use, the split butterfly valve permits the discrete material supply means and material receiving means to be mechanically docked (see
FIG. 1
) and thereafter operates as a normal fixed valve by controlling material flow rate across the interface. Thus, with reference to FIG.
1
(
a
), the split butterfly valve is shown with the two parts separated and with the material supply means isolated from the material receiving means. In FIG.
1
(
b
), the respective parts of the split butterfly valve are mechanically docked and the butterfly remains closed to contain the material in the respective means. In FIG.
1
(
c
), the butterfly valve is opened to allow material to flow across the valve interface. After transfer is complete, the parts are closed to re-isolate the material supply means from the material receiving means and are mechanically undocked.
During the transfer of potentially toxic materials, there is in general a need to provide a safe and contained local environment at and in the vicinity of the interface of the material supply means (e.g., a powder bin) and the material receiving means (e.g., a chemical reaction vessel). Current operating parameters and acceptable operator exposure levels have increased the need to address certain performance inadequacies of devices such as split butterfly valves during material transfer.
A particular disadvantage of the split butterfly valve is observed when material transfer is complete and the two parts of the valve are closed and undocked. During the transfer process, the edge faces of the open valve are exposed to extraneous material. Furthermore, extraneous material may become entrained on the split joint faces and is exposed when the valve is closed and the two parts are undocked. It will be appreciated that this type of exposure to extraneous material represents a hazard to operators, in particular where the extraneous material is of a toxic nature. It will also be appreciated that cleaning of the apparatus in the open air (i.e., outside a contained environment) is hazardous, e.g., airborne exposure and exposure through handling of cleaning wipes, etc.
Fine powders are capable of being suspended in the local working environment where they may be inhaled by operators with potentially disastrous consequences. In handling dangerous and potentially toxic powdered products, it is imperative that a safe breathing zone is provided for the operator which falls within current acceptable levels of exposure (e.g., within a magnitude of micrograms per cubic meter).
OBJECTS OF THE INVENTION
The invention seeks to address the present needs by providing a containment device which reduces the tendency for extraneous material to escape into the working environment of a material transfer apparatus. In particular, the present invention seeks to overcome the impracticality of completely sealing the environment in and around a material transfer apparatus by providing a device for localised containment which greatly improves the safety aspects of the material transfer apparatus and lowers the risk of material contamination.
SUMMARY OF THE INVENTION
According to one aspect the present invention, a device is provided for localised containment of extraneous material at and in the vicinity of the interface between a material receiving means and a material dispensing means. The device comprises a container having a containment chamber. The containment chamber has a first open end adapted to receive at least a part of the material dispensing means, a second open end adapted to receive at least a part of the material receiving means, and an air inlet. The device further comprises means for ventilating the interior of the containment chamber whereby extraneous material at and in the vicinity of the interface between the material receiving means and the material dispensing means is transported to a remote location.
Added to the advantages of increased operator safety achievable by minimizing the risk of exposure to extraneous material, the device of the invention also minimizes the risk of material contamination. In the pharmaceutical industry, this is important in enabling the industry's strict cleanliness and hygiene codes to be met. The device advantageously removes the majority of airborne particulates which might otherwise may be entrained into the material receiving means.
The device of the invention may be adapted to control the flow characteristics and air quality at and in the vicinity of the interface between the material receiving means and the material dispensing means using forced ventilation. Traditionally, forced ventilation falls into three main categories:
1. Up flow of the surrounding air at a velocity which captures the contaminants and carries them along with the air flow and subsequently into a filtration system before being exhausted to atmosphere. Exhaust is accomplished at high level relative to the contaminant source.
2. Down flow of the surrounding air which draws contaminants to a level below that of the typical operators breathing zone. Exhaust is usually accomplished at low level relative to the contaminant source.
3. Cross flow of the surrounding air at an appropriate capture velocity which evacuates contaminants in a horizontal plane. Exhaust and filtration systems may be set at any level when using this technique.
Whilst each forced ventilation system may be used in the device of the invention and has particular advantages and disadvantages, the device is preferably adapted to provide cross flow ventilation. Although it is generally the most difficult system to adopt, cross flow avoids contamination of horizontal upper or lower surfaces which might otherwise occur with vertical air flow (ie up flow or down flow). In other words, it lowers the risk of fallout and settling of powdered particulates and helps to maintain the recommended safe environmental conditions of the operator's breathing zone and of the operator working area in general.
In adopting the cross flow method (or any other ventilation method), it will be within the capabilities of the man skilled in the art to optimise particulate capture velocities, control the characteristics of the air flow and ensure clean working zones. For example, the free volumetric space through which the forced airflow is channelled may be balanced with the size of the air inlet aperture and the exhaust ducting. Air flow may be induced by any avail

Affiliated with

Also associated with

Rating

Containment device does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Containment device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Containment device will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2819306