DOUBLE SIDED WORK STATION

Abstract: A work station (10) includes a pressure cabinet (22) and a work surface (60) forming the top of the pressure cabinet. The work surface is perforated along at least a portion of the work surface. A pressure inducing assembly (34) is located within the cabinet below the work surface to draw air into the cabinet. A plenum (14) is coupled to the pressure cabinet. An air chamber (16) is mounted on the plenum and receives air passing from the cabinet through the air plenum to the air chamber. The air chamber then guides the air towards the work surface (60).

Description: DOUBLE SIDED WORK STATION BACKGROUND OF THE INVENTION This invention is directed to a work station at which laboratory animals can be moved from one cage to another, and in particular, a work station which protects the animals within the cage from contamination while being worked on. Laminar flow work stations are known in the art, such as, for example, from Lab Products model numbers Stay-Clean 30909B and 30910B. Those work stations include a table surface enclosed on three-sides by a hood that extends generally upward from the table surface. That configuration creates a housing about the work surface with one open side thereby limiting access and viewability to the work surface. At least a portion of the work surface is perforated to allow air to flow therethrough. Flow blowers are disposed beneath the surface to cause a negative pressure at the table surface perforations to draw air from the work surface, and front exterior area, in through the work surface to filter the air. In this way, any impurities at the work station which are airborne and likely to contaminate worker and animals at the work station are prevented from reaching the worker or animals. While such work stations have been satisfactory, the requirement for the large three-sided containment hood makes the work station bulky, heavy, and limits access to the work station. Only one or two workers working at the open side of the hood can access the work station. Accordingly, a work station which overcomes these deficiencies is desired. SUMMARY OF THE INVENTION In an embodiment of the present invention, a work station has a base and a perforated work surface supported thereon. First and second plenums extend from the base to support a top cabinet disposed above and at least coextensive with the work surface. The top cabinet has a perforated lower surface facing the work surface. Negative pressure blowers are disposed between the work surface and the air plenums to draw air through the work surface and cause it to pass generally upward through the plenums and through the top cabinet to be expelled or forced back toward the work surface below. In a preferred embodiment of the present invention, a filter is disposed between the work surface and the lower surface of the cabinet to filter the air drawn by the negative pressure blowers. A removable divider may be provided to essentially divide the work surface and to separate one side of the work surface (and work station) from the other. The divider prevents cross-contamination between one side of the work surface and another side of the work surface such as when two users are simultaneously working on opposite sides of the work station. The height of the work station and work surface may be adjusted manually by a crank provided on the base. Accordingly, it is an object of the invention to provide an improved work station. Still, another object of the invention is to provide a work station lighter in weight with increased stability. A further object of the invention is to provide a work station which provides protection to the room in which the work station is utilized as well as to the users of the work station while allowing more access to the work station by the user. Still another object of the invention is to provide a work station which allows simultaneous working on a greater number of cages without increasing the overall size of the work bench. Yet another object of the invention is to utilize recycled air to provide protection from cross contamination over a greater area. Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification. The invention accordingly comprises the features of construction, combination of elements, and arrangement of parts which will be exemplified in the construction hereinafter set forth, and the scope of the invention will be indicated in the claims. BRIEF DESCRIPTION OF THE DRAWINGS For a fuller understanding of the invention, reference is had to the following description taken in connection with the accompanying drawings, in which: FIG. 1 is a rear perspective view of a double-sided work station constructed in accordance with an embodiment of the present invention; FIG. 2 is a front perspective view of the work station depicted in FIG. 1; FIG. 3 is a side elevational view of the work station depicted in FIG. 1 ; FIG. 4 is a sectional view of the work station of FIG. 2 taken along line 4-4; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings in detail, a double-sided work station, generally indicated as 10, constructed in accordance with an embodiment of the present invention is depicted in FIGS. 1-4. Referring first to FIG. 1, the inventive work station 10 generally includes a base 12 and a top cabinet 16 supported by plenums 14 extending generally upward and out of the base 12. The base includes a wheel assembly 18 that facilitates easy movement of the work station 10. A top surface 60 of the base 12 has a plurality of perforations 62 provided at least partially about its perimeter. A divider 90 separates one side of the work station 10 from the other. Thus, the divider 90, and the generally open configuration of the work station (i.e., user access may be from either side) provide a double-sided work station 10. A laminate shroud 63 may also extend about top cabinet 16 to better confine and guide air passing from the top cabinet 16 to the base 12, as described in more detail below. A removable access plate 24 provides access to the interior of a pressure cabinet 22 provided in the base 12 for repair and maintenance, and for closing cabinet 22 during use of the work station 10 As shown in FIG. 4, pressure cabinet 22 has a substantially hollow interior divided into first and second chambers 26, 28 by a center cabinet partition 27. The construction of chambers 26 and 28 is substantially identical and therefore, like numbers are utilized for describing each chamber and, unless otherwise indicated, the description of chamber 26 is substantially identical to the following description of chamber 28, and therefore will not be repeated. A first support 30 is mounted between center cabinet partition 27 and a side wall 32 of plenum 14 extending into pressure cabinet 22. A motorized blower assembly 34 is mounted on support 30 and provides a negative pressure to draw air through the blower assembly 34 and into chamber 28. Blower assembly 34 includes a motor 36 for driving a fan 38. A prefilter 40 is mounted upstream (in an airflow direction) of fan 38 to prefilter air being drawn into the chamber 28. A grill 42 is disposed between filter 40 and fan 38 to protect the operator from the fan blades when changing filter. Motorized blower 34 is mounted to support 30 by vibration isolator motor mounts 44. A communication cabinet 46 communicates with air plenum 14. Air communication cabinet 46 has an opening 48 into respective chamber 28 through which air may flow from the chamber 28 into air plenum 14. A HEPA filter 50 is disposed at opening 48 to filter the air prior to its passage into plenum 14. A grill 52 is mounted between HEPA filter 50 and the remainder of cabinet 26 to protect the filter 50 from any large objects or service technicians which may damage the filter. A first flange 56 is mounted around base 12 near the top of the base 12 and extends partially into pressure cabinet 22. A second flange 58 extends from flange 56 and holds a pan 54 within pressure cabinet 22. Pan 54 is provided to further protect blower assemblies 34 from spillage of cleaning agents and collect any dirt which may pass through perforated opening 62 which are not air-borne. Work surface 60 is supported by flange 56 so as to form a top surface of base 12. Surface 60 is formed with a plurality of air intake slots or perforations 62 (see, e.g., FIG. 1), which although not shown in FIG. 4 for clarity, preferably extend completely about the perimeter of surface 60. In another embodiment of the present invention, the perforations 62 could extend across substantially the entire surface of the top of surface 60 which may actually result in reduced weight of the overall work station 10 and improved air flow and circulation in and through the work station 10. With continued reference to FIGS. 1-4, top cabinet 16 is supported directly above surface 60 by plenums 14, and is at least coextensive with surface 60 so as to define a work space 120 between the top cabinet 16 and surface 60. Top cabinet 16 has an air chamber 68 defined therein which communicates with plenums 14 and has a lower surface with a plurality of perforations 72 defined therethrough that defines an air diffuser ceiling 70 for the work station 10. The perforations 72 permit air to pass from the chamber 68 in a generally uniform pattern in the general direction of arrows F and A and toward surface 60. This results in the recirculation of air between an input at surface 60 (via perforations 62) and an output at ceiling 70 (via perforations 72). By placing perforations 72 at least at the periphery of ceiling 70 so as to correspond with perforations in 62 at the work surface 60, a curtain of filtered air is provided that separates the work space of work station 10 from the ambient environment and also captures some ambient air. Referring next to FIG. 4, an air-flow path is defined in and through the work station 10 as depicted by arrows A, B, C, D, E. The air-flow path thus defined is generally facilitated by the blower assembly 34 which draws air in through the perforations 62 in the surface 60 creating a negative pressure area above the surface 60, i.e. in the work space 120. Although referred to in the singular, it will be obvious to persons skilled in the art and from the disclosure provided herein that both blower assemblies 34 facilitate air flow in and through the work station 10. Air is then directed by the blower assembly 34 into chamber 28 and into communicating cabinet 46. Following arrow E, the air is caused to flow upward through plenum 14, into chamber 68, and is then drawn generally downward toward the surface 60, as indicated by arrows F and A. A curtain of air is thus created between the top cabinet 16 and base 12 so that the environment provided in the work space 120 is controllable and free from contamination from ambient air (i.e., outside of the air curtain). Top cabinet 16 also supports therein a fluorescent light source 74 (see, e.g., FIG. 4). A generally translucent panel 80 is provided at the top of air chamber 68 so the light can shine through into chamber 68 and through the translucent ceiling 70 to provide illumination of the work surface 60. A power cord 82 mounted within top cabinet 16 eliminates the need for a cord at floor-level and is connected and provides power to light source 74, motors 36, and in an automated embodiment, to crank assembly 64. A retractable plug 84 connected to power cord reel 82 may be selectively connected to a remote power source, e.g., a wall outlet, power panel, etc.. A control panel 86 is mounted to top cabinet 16 and controls the speed of blower assemblies 34 and in turn, the amount of air pressure provided in pressure cabinet 22 and air chamber 68, monitoring HEPA filter 50, on and off control of the light source 74, and power for the work station via a plurality of switches 88 (see, e.g., FIG. 2). A laminate shroud 63 may also extend about top cabinet 16 to better confine and guide the curtain of air. As can be seen clearly in FIG. 1, because top cabinet 16 is supported at the sides by plenums 14, the work station 10 is an open work station to which access can be provided from both the front and back. Therefore, at least two workers can work on separate cages, both on the same side of the work station 10 or opposite each other. In order to prevent cross-contamination of the animals within the cages between workers, a divider 90 is provided. Divider 90 is substantially a screen having a frame 92 and a body portion 94 supported therein. Frame 92 includes pegs 96 which are received by holes 98 in surface 60 to allow easy removal of divider 90. During use, the work station 10 may be wheeled into position near a ventilated rack having one or more animal cages contained thereon to be worked on at work station 10. Work station 10 is connected to a power supply by plugging power cord 84 into the building power source, for example. The blower assemblies 34 are then turned on by use of a switch 88 on control panel 86. This creates a negative pressure at work surface 60 and causes air to be drawn through each of cabinets 26, 28. As air passes through perforations 62, the air is filtered through prefilter 40 and then filtered again through HEPA filter 50 as it passes up plenum 14 into air chamber 68. The air creates a positive pressure in air chamber 68. The air then moves through perforations 72 of air chamber 68 down towards surface 60. This in effect provides an air curtain about the working surface 60 and a pressurized volume above the work surface 60. A first technician may remove a cage from the rack and place it on the surface 60. The technician is now isolated from the cage by the air curtain. Additionally, the cage is now isolated from the ambient environment outside of the work station and outside of the rack by the air curtain. The cage may now be opened without fear of cross-contamination of the animals within the cage by the ambient environment, and visa-versa. Furthermore, a second technician may take a cage and place it on the surface 60 on the other side of barrier 90 and open the cage without fear of cross-contamination with the first technician's cage. After operation or exchange of animals to a clean cage, the cage would then be returned to the rack. The work station 10 (i.e., the surface 60) may be selectively raised and lower to provide a comfortable height for a technician. In a first embodiment, and with reference to FIGS. 1 and 3, a manual crank mechanism 64 may be used to adjust the height of surface 60 relative to base 12. A handle 66 may be provided for a user to turn, causing the work station 10 to raise or lower from the wheel assembly 18. In an alternative embodiment, a the crank mechanism 64 may include hydraulics for easier positioning and movement of the surface 60. It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained and, since certain changes may be made in the above construction without departing from the spirit and scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense. It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention which, as a matter of language, might be said to fall there between.

Claims: CLAIMS WHAT IS CLAIMED IS: 1. A double-sided work station having an open front side and an open back side, said work station comprising: a pressure cabinet; a work surface disposed on and forming a top to the pressure cabinet and being accessible by a worker from either one of the front side or the back side of the work station; the work surface having perforations along at least a portion thereof; a first pressure inducing assembly located within said pressure cabinet for moving air through said perforations; a first air plenum coupled to said pressure cabinet providing a channel through which air may be caused to move; an air chamber mounted on said first air plenum and coupled thereto for receiving air from said first air plenum and guiding said received air toward said work surface. 2. The work station of claim 1, further comprising a filter disposed between said first pressure inducing assembly and said first air plenum. 3. The work station of claim 1, further comprising a divider extending across a length of said work surface to divide said work surface into a first portion and second portion, said first portion being isolated from said second portion. 4. The work station of claim 1, further comprising a second air plenum coupled to said pressure cabinet providing a channel through which air may be caused to move. 5. The work station of claim 1, further comprising: a second air plenum coupled to said pressure cabinet providing a channel through which air may be caused to move; a center cabinet partition disposed within said pressure cabinet for separating said pressure cabinet into a first pressure cabinet and a second pressure cabinet; and a second pressure inducing assembly being disposed in said second pressure cabinet and said first pressure inducing assembly being disposed in said first cabinet and, said first pressure cabinet communicating with said first plenum and said second pressure cabinet communicating with said second plenum. 6. The work station of claim 1, wherein said perforations are formed about a periphery of said work surface. 7. The work station of claim 5, further comprising a second filter disposed between said second pressure inducing assembly and said second plenum. 8. The work station of claim 3, wherein said divider is removable.

Inventors: DARBY THOMAS, DIETRICH ERIC, MURRAY DALE, DARBY, THOMAS, DIETRICH, ERIC, MURRAY, DALE
Applicants: PRODUCTS LAB INC, LAB PRODUCTS INC.
Application year: 2000
Main classification: A01K1
IPC codes: A01K1, A01K13