Abstract: In a laboratory hood system having a housing with an access window opening into an interior work chamber for performing laboratory processes, and an air circulation system for creating an air flow from the laboratory environment inwardly through the access window into the work chamber for preventing hazardous materials from escaping into the laboratory environment through the access window, one or more air intake control devices are disposed in a selected location or locations at the access window to overcome any tendency for air turbulence to occur. The air intake control device has an air flow channel extending from an air intake opening to the laboratory environment to an air discharge opening to the work chamber, with a constriction in the channel for causing a venturi-effect increase in air velocity while flowing through the channel to promote non-turbulent air flow entering the work chamber at the selected location or locations.

Abstract: An improved filter mounting mechanism for laboratory work cabinets, especially biological safety cabinets, enables simple and quick removal and replacement of a filter supported in the cabinet housing between a work chamber and a filtration chamber. The filter mounting mechanism includes a stationary filter support surface between the work chamber and the filtration chamber, and a filter clamping surface movable toward and away from the filter support surface between a clamping position relatively proximal to the filter support surface for holding the filter in an operational disposition against the filter support surface and an installation position relatively distal to the filter support surface for permitting insertion and removal of the filter between the filter support and clamping surfaces. An extensible and retractable linkage mechanism, e.g.

Abstract: A ductless laboratory hood apparatus includes a housing defining an interior work chamber, a filtration chamber, an access window opening into the work chamber from an ambient laboratory environment, and an exhaust outlet opening from the filtration chamber into the laboratory environment, a filter system disposed between the work and filtration chambers, and an air circulation system for creating and directing an airstream to flow from the laboratory environment through the access window, the work chamber, the filter system, the filtration chamber, and the exhaust outlet to return into the laboratory environment. The filter system has both a main filter whose constituent material is highly efficient but is also degradable if exposed directly to laboratory processes, and an attenuation filter disposed between the work chamber and the main filter to intercept and attenuate laboratory processes that potentially degrade the main filter, thereby preventing degradation of the main filter.

Abstract: A ductless laboratory hood apparatus includes a housing defining an interior work chamber, a filtration chamber, an access window opening into the work chamber from an ambient laboratory environment, and an exhaust outlet opening from the filtration chamber into the laboratory environment, a filter system disposed between the work and filtration chambers, and an air circulation system for creating and directing an airstream to flow from the laboratory environment through the access window, the work chamber, the filter system, the filtration chamber, and the exhaust outlet to return into the laboratory environment. The filter system has both a main filter whose constituent material is highly efficient but is also degradable if exposed directly to laboratory processes, and an attenuation filter disposed between the work chamber and the main filter to intercept and attenuate laboratory processes that potentially degrade the main filter, thereby preventing degradation of the main filter.

Abstract: A system for displaying information related to an operational parameter of a biological safety cabinet that may change during ongoing operation thereof, comprises a sensor for detecting a prevailing value of the operational parameter at least periodically during operation, a display comprising a pictorial graphic having a series of adjacent arcuate segments graphically representing a range of possible values for the operational parameter between a minimum value represented by a first segment, a maximum value represented by a last segment, and incremental intermediate values represented by a plurality of segments intervening between the first and last segments, and a processor associated with the sensor and with the display for comparing the prevailing value of the operational parameter to the range of possible values and selectively actuate illumination of all, none or another number of the segments to visually signify the prevailing value in relation to the range of values.

Abstract: A biological safety cabinet with several air flow directional control enhancements. A perforated air intake grille within the work chamber inwardly adjacent the user access opening has a forwardly facing make-up air intake surface and a rearwardly facing internal air intake surface angled in converging relation to promote a physical division between intake of ambient air and internal air into the cabinet's air recirculation system. An aerodynamic user arm rest is affixed to a support stand to extend alongside the access opening at a spacing outwardly from the housing to assist in directing make-up air to the ambient air intake opening without cross-contamination between the arm rest and the work chamber. An air transmission grille above the work chamber has a horizontal main extent terminating at a spacing from the sash and an upwardly angled extent adjacent the sash to direct increased laminar air flow downwardly along the sash.

Abstract: An improved system and method for monitoring contamination loading of a filter in a biological safety cabinet comprising a housing defining a work chamber and a filtration chamber, a system for circulating air between the work chamber and the filtration chamber via a fan which draws air under negative pressure from the work chamber and delivers the air under positive pressure through the filter and into the filtration chamber. The filter monitoring system determines a pressure differential between the negative and positive air pressure at opposite sides of the fan, and evaluates the degree of contamination loading of the filter on the basis of the pressure differential. An air flow baffle is disposed within the filtration chamber adjacent the fan for dividing the pressurized air delivered by the fan and partially redirecting a portion thereof for more uniformly delivering the air to the filter.

Abstract: A shelf support system that includes a shelf member having a flat support surface, and a flange adjacent at least one end of the support surface that includes a downwardly extending wall portion and an inwardly extending wall portion connected thereto, the inwardly extending wall portion having an edge formed with a notch having a predetermined width. At least one support bracket includes a U-shaped mounting flange having an upwardly extending connecting wall that includes a spacer wall portion having a predetermined width and an engagement wall portion that is connected to the spacer wall portion and that extends beyond the predetermined width of the spacer wall portion. The support bracket is connected to the shelf member by positioning the U-shaped mounting flange of the support bracket within the wall portions of the shelf member to provide a secure connection without the use of tools.

Abstract: A fume hood adapted to be connected to an exhaust system, the fume hood including a cabinet formed with a chamber having a generally flat bottom wall and a sash door mounted at the front end of the chamber for movement in a vertical plane to provide an access opening to the chamber. An air directing member is mounted on the cabinet outside of the plane of movement of the sash door relative to the chamber and it is generally aligned with the bottom wall. The air directing member is formed with an opening positioned to cause a first path of outside air to flow into the chamber along the surface of the bottom wall and being formed with another portion for directing a second path of outside air in a direction generally parallel to and above the first path.

Abstract: A counterweight apparatus is provided for automatically self-returning an enclosure sash or other closure member to at least one preselected intermediate position when released after being opened beyond that intermediate position and for selectively maintaining the closure member in at-rest positions, when released, between that intermediate position and a fully closed position.

Abstract: A housing of a fume hood includes walls defining a chamber for containment of air therein. One of the walls defines an air passageway opening into the chamber, and a sensor is located outside of the chamber and measures airflow velocity through the air passageway into the fume hood. An elongate, perforated tubular member supported within the chamber includes a first end mounted to the wall of the chamber defining the air passageway in surrounding relation thereto, and a second, distal end substantially closed off from the contaminated air within the chamber whereby airflow through the air passageway into the fume hood generally must pass through a perforation in the tubular member to gain access into the air chamber. The tubular member extends across the width of the chamber and airflow velocity through the air passage is representative of overall air entry velocity into the air chamber.

Abstract: A laboratory fume hood apparatus and method for containing contaminated air within the confines of the fume hood which includes a generally rectangular housing having a vertically movable door for providing an opening to the interior of the fume hood. A contoured air foil on the bottom of the door, an adjacent sill, openings in the door, a bypass slot formed in the housing and an air directing wall portion within the housing combine to provide a flow of outside air downwardly along the interior surface of the door and then directly toward an exhaust plenum located at the rear wall of the interior cabinet.

Abstract: A mold (10) for molding thin resin sheets includes a center mold plate (12) and two side mold plates (14, 16) disposed on opposite sides of the center mold plate. The mold plates are oriented generally vertically and parallel to each other, and the side mold plates are narrowly spaced from the center mold plate to define a pair of generally vertical mold cavities (18, 20) on either side of the center mold plate. The side mold plates may optionally include recesses (51) in their generally planar mold surfaces (38, 40) adjacent at least one longitudinal edge of the plate, for molding thin resin sheets with integral edge flanges. The mold includes spacer strips (46, 47) for spacing the side mold plates a precise distance from the center mold plate and parallel thereto. The mold thus permits molding of thin resin sheets having precisely controlled uniform thickness.

Abstract: The laboratory countertop of the present invention utilizes a thin chemical and heat resistant surfacing panel in the form of a thin planar sheet made of a cured thermoset resin composition. In accordance with one broad aspect of the present invention, the thin chemical and heat resistant surfacing panel is mounted overlying a backing panel of a less expensive and lighter material such as particle board or plywood. The surfacing panel is of a cast, monolithic construction and has a width at least 50 times its thickness and a length at least 100 times its thickness. The surfacing panel can additionally include an edge flange integrally formed with the thin planar sheet. The edge flange hides the underlying backing panel from view and gives the countertop the appearance of a unitary thick slab.