CONTAMINATION CONTROL APPARATUS

• US 3,811,250 A
• Filed: 04/25/1973
• Issued: 05/21/1974
• Est. Priority Date: 12/15/1971
• Status: Expired due to Term

• Current Assignee: James Mcfarland Jr. Fowler
• Original Assignee: James Mcfarland Jr. Fowler
• Inventors: Fowler, James McFarland Jr.
• Primary Examiner(s): Nozick, Bernard
• Application Number:
  US05/354,217
• Time in Patent Office: 391 Days
• Field of Search: 55/467,470-472,473,274,DIG.29 98/115LH 62/256 73/212 417/43
• US Class Current: 96/422
• CPC Class Codes: B01D 46/00 Filters or filtering processes specially modified for separating dispersed particles from gases or vapours filtering elements B01D24/00-B01D35/00; filtering material B01D39/00; their regeneration outside the filters B01D41/00
• CPC Class Codes: B08B 15/023 Fume cabinets or cupboards, e.g. for laboratories
• CPC Class Codes: B08B 15/026 Boxes for removal of dirt, e.g. for cleaning brakes, glove- boxes
• CPC Class Codes: B08B 2215/003 with the assistance of blowing nozzles
• CPC Class Codes: Y10S 55/29 Air curtains

Abstract

The contamination control apparatus of this invention includes a hollow cabinet having a work area in one portion thereof and an opening therein permitting access to the work area from the exterior of the cabinet. Decontamination and air supply means are in the cabinet and positioned so that air discharge therefrom will be decontaminated and then passed into the work area. Diffusion means are mounted in the cabinet and positioned between the decontamination and supply means and the work area to facilitate the diffusion of the air as it enters the work area. Consequently, the air flows uniformly through the work area and assist in providing a clean air curtain over the access opening to the work area to facilitate the prevention of contaminated air from leaving or entering the work area through the access opening. A series of interconnected air plenum chambers are in the cabinet in communication with the work area, decontamination and air supply means, and the opening to the exterior of the cabinet to permit the air passing through the work area and a portion of air from outside of the cabinet to be directed to the decontamination and air supply means. Negative pressure reducing means are in the cabinet to direct a predetermined amount of decontaminated air out of the cabinet sufficient to maintain a lesser pressure within the cabinet and exteriorly thereof and, finally, air velocity indicator and control means are mounted on the cabinet to facilitate the control of air flow within the cabinet.

Claims

1. A contamination control apparatus comprising:

a hollow cabinet having a work surface mounted in one portion thereof and an opening in the front wall of the cabinet permitting access and being adjacent to a portion of the work surface;

air supply means mounted in said cabinet;

high efficiency filter means mounted in said cabinet and connected to the air supply means by a plenum and positioned so that air discharge from said air supply means passes therethrough for decontamination and diffusion of the air;

diffusion means mounted in the cabinet between the high efficiency filter means and the work surface for diffusion as air enters the work area so that laminar flow is provided on the work surface and providing a controlled flow passage for a substantial portion of the air from the air supply means to the work surface;

means defining a channel mounted in said cabinet adjacent the access opening and adjacent the diffusion means for communication with flow from the filter for directing a predetermined portion of the filter air discharge from the air supply means across the access opening at a higher velocity than the air passing through the diffusion means and to thereby form an air curtain across the access opening within the cabinet and prevent interchangeability of air between the work area and the exterior of the cabinet;

exhaust means from said cabinet communicating with said work surface to direct a predetermined amount of air from said cabinet;

said exhaust means including negative pressure producing means sufficient to maintain a lesser pressure within a portion of said cabinet than exteriorly thereof;

said exhaust means including air direction means within said cabinet to direct the flow of air therethrough with only a negative pressure condition present in that portion of the cabinet adjacent to the exterior walls thereof to minimize the danger of leakage of air from the interior of the cabinet; and

means for directing a portion of the air from the work surface to the air supply blower.

2. The invention in accordance with claim 1 wherein a series of interconnected air plenum chambers are in said cabinet in communication with said work surface, said filter and diffusion means, said air supply means, said access opening, and said exhaust means, to facilitate the direction of air flow with respect to the interior of said cabinet.

3. The invention in accordance with claim 1 wherein said air supply means includes an air supply blower mounted in said cabinet and positioned so that air discharge therefrom will be directed into said work area, and said exhaust means including an exhaust blower mounted in said cabinet and in communication with the exterior of said cabinet to direct a predetermined amount of air out of said cabinet, and an exhaust filter mounted in said cabinet between the exhaust blower and the exterior of said cabinet to assure that only clean air is removed from the exterior of said cabinet.

4. The invention in accordance with claim 1 wherein said work surface includes the zone defined by a horizontal table and at least two substantially vertical plates spaced from one another and spaced above said table to permit removal of air from said work surface.

5. The invention in accordance with claim 1 wherein said diffusion means is a screen forming a substantial portion of the upper boundary of the work area and is positioned with respect to said filter means and air supply means so that a substantial portion of the air supply therefrom passes through said screen.

6. The invention in accordance with claim 1 wherein said channel means includes two substantially vertical plates in said cabinet adjacent to said work area and terminating above said access opening with the channel formed between said plates communicating at one end with the exhaust side of said filter and at the other end with the access opening so that a portion of the air exhausted from said filter passes at a relativEly high velocity through said channel and across said access opening to provide an air curtain.

7. The invention in accordance with claim 1 wherein air velocity indicator means are mounted on said cabinet to monitor the air velocity in said cabinet.

8. The invention in accordance with claim 7 wherein control means are on said cabinet in connection with said air supply means to facilitate the adjustment of air flow within said cabinet in response to an indication of said air velocity indicator.