Laboratory work station with controllable environment

Means and methods for maintaining laboratory work stations which have essentially open work areas, free of noxious and malodorous air contaminants by the use of tempered induction air combined with contaminant bearing exhaust air to limit the throughput of more expensive conditioned air. The means enables both the utilization of an integral lighting unit and the efficient collection of noxious air without creating unwanted drafts and currents.

INTRODUCTION 
The present invention relates generally to a laboratory work station with a 
controlled environment and more particularly a unique work station 
providing for the treatment, management, containment, and disposition of 
contaminated air normally created in processing laboratories or teaching 
laboratories. Specifically, the assembly hereof provides means to control 
inhabitant exposure to fumes, gases, and particulates having potentially 
toxic or malodorous properties while reducing the use of temperature 
controlled air to a minimum. 
BACKGROUND OF THE INVENTION 
Energy conservation and protection from noxious air contaminants represents 
two divergent goals for a conditioned air environment, that is prewarmed 
air for cold climates and precooled for warm climates. The use of large 
amounts of make-up air through an exhaust system can effectively sweep the 
temperature controlled area free from air contaminants. However, the use 
of such energy conditioned air in large quantities inevitably results in 
untoward and expensive energy usage. 
The use of totally enclosed hoods which limit the availability of 
accessible work area and the ability to observe what occurs therewithin, 
while effectively controlling the dispersion of noxious fumes, does not 
lend itself to adequate or desirable supervision when untrained students 
are conducting those chemical experiments which are so necessary to the 
learning process. 
The present invention provides the educational laboratory with good visual 
observation, minimal energy requirements, plus effective air and fume 
control, all of which are essential to teaching the laboratory arts, 
especially chemistry. It accomplishes these goals by providing make-up air 
which is used primarily as the carrier fluid for said noxious fumes and 
particulates, thus avoiding the use of large volumes of expensive 
temperature controlled air. In moderate climates, outside air can be used 
directly. In severe climates, the outdoor air should be tempered before 
use. 
The extraction of noxious gases and fumes takes place near the bench top, 
thus affording the most efficient use of the air induction/partial 
pressure air removal that is easily adjustable to prevent unwanted 
currents or drafts, even at low air induction volumes. 
BRIEF SUMMARY OF THE INVENTION 
The present invention provides means and methods for maintaining laboratory 
work stations which have essentially open work areas, free of noxious and 
malodorous air contaminants by the use of tempered induction air combined 
with contaminant bearing exhaust air to limit the throughput of the more 
expensive conditioned air. The equipment design and implementation allow 
the use of an integral lighting unit and the efficient collection of 
noxious air without incurring unwanted drafts or currents. 
Accordingly, a prime object of the present invention is to provide a better 
and more efficient laboratory work station having a novel air distribution 
device to remove odors, fumes and irritants from chemistry laboratories. 
Another object of the present invention is to provide a new and improved 
laboratory work station with a controllable environment having in 
combination a supply plenum, distribution means, a diffusion plate, an air 
canopy, an exhaust plenum and a perforated exhaust equalization plate. 
A further object of the present invention is to provide new and improved 
means for removing obnoxious odors and fumes from a chemical laboratory 
work bench employing a low velocity diffusion plate. 
Still another object of the present invention is to provide new and 
improved means for controlling the environment on a chemistry laboratory 
work bench which allows one or more appropriate light fixtures to be 
installed therein without interference with the air flow therethrough. 
These and still further objects as shall hereinafter appear are readily 
fulfilled by the present invention in a remarkably unexpected manner as 
will be readily discerned from the following detailed description of an 
exemplary embodiment thereof, especially when read in conjunction with the 
accompanying drawing in which like parts bear like numerals through the 
several views.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to the drawing and particularly to FIG. 1, a laboratory work 
station embodying the present invention is identified by the general 
reference 10. Each work station 10 comprises a contaminant collection hood 
assembly 11 attached to a laboratory bench 12. Each hood assembly 11 has 
an ingress air diffusion channel 14 extending the entire length of the 
hood assembly 11 and supplied by one or more ingress air supply ducts 15 
attached to and forming a part of ingress air diffusion channel 14. 
Ingress air slotted baffle 16 is formed as the partitioning floor of 
ingress air diffusion channel 14 and coacts therewith to proportion the 
air flow along the length thereof. A perforated plate 17 is attached to 
the underside of slotted baffle 16 to complete the ingress air assembly 18 
which extends between Plexiglass.RTM. end plates 20, 21, respectively. 
Appropriate interior illumination is provided for work station 10 by the 
internal light 22 which is mounted below perforated plate 17 and extends 
axially along hood assembly 11. Each light 22 is normally a fixture of 
about four feet in length. A plurality of such fixtures may be used on 
eight foot centers when longer hood assemblies 11 are employed to meet the 
exigencies of a given installation. 
As shown in FIGS. 1 and 3, ingress air assembly 18 is supported upon a 
series of bipodal supports 24 which are disposed in spaced generally 
parallel relationship to each other along the axial length of work station 
10. 
Each member of each bipodal support 24 extends downwardly from the adjacent 
canopy side 25 past egress air channel 26 into seated engagement with 
bench top 27. Egress air channel 26 passes through air duct 29 and out 
exit air duct 31. Air duct 29 is supported in spaced relationship to bench 
top 27 by the bipodal supports 24 and has a perforated plate 28 disposed 
in the mouth 30 thereof in juxtaposition to receive the existing air 
therethrough. As shown in FIG. 1, the air flow pattern enters through 
ducts 15 and passes through baffle 16 and plate 17 around light fixture 22 
to sweep along the inner surface of canopy sides 25 through the work area 
and into mouth 30 for exit via egress air duct 29 and exit air duct 31. 
Plexiglass.RTM. shields 32 are mounted as with suitable hinges 33 at one or 
more locations along the outreaching edge 34, preferably both front and 
back, of sloped canopy members 25 of ingress air assembly 18. Shields 32 
may be pivoted about hinges 33 from a nonfunctional position on top of 
canopy member 25 into a functional position depending vertically from edge 
34 of canopy 25. 
Ancillary fans are used to supply ingress air. This air may be tempered or 
partially treated to avoid (a) condensation problems if the ingress air is 
cold, or (b) excessive heating, if the ingress air supply is hot. Such 
treatment is minimal. Air supply may be sourced from the outside 
environment or it may originate from an auxiliary plenum area depending on 
the climate where the laboratory is located. Egress air is removed from 
the work bench surface through the use of the negative pressure created by 
an ancillary exhaust fan. 
In operation, tempered ingress air is supplied through ingress air duct 15 
and flows over and through slotted plate 16 which distributes and 
regulates the air flow that is passed to and through perforated plate 17 
that further directs the air flow over and around the lighting fixtures 
22. The air flow is further contained by sloped canopy sides 25 and 
plexiglass end plates 20, 21 and plexiglass shields 32 when they are 
deployed vertically about hinges 33. 
The ingress air, provided as described above, is mixed with a small 
quantity of conditioned air and the noxious fumes generated at the work 
station 10 and the resulting mixture is drawn into and through perforated 
plate 28 which controls the air flow and prevents high velocity regions of 
extraction before passing through egress channel 26 and into egress air 
duct 29 to the ancillary exhaust fan and finally into the disposal, 
filtration or wash system, whichever is selected for the particular 
installation. 
The ingress induction air supplies most of the make-up air that is required 
for the system thereby retaining within the system most of the expensive 
completely air conditioned room air and affording economical and complete 
fume or noxious air removal. Further fume protection is provided through 
the use of the plexiglass shields 32 that may be placed in a vertical 
depending position in the event of copious fume production, or to provide 
protection from violent reactions. The ingress induction air is controlled 
to prevent its intrusion into the conditioned room air. The system is 
designed to supply, for example, 60 CFM induction air per lineal foot of 
bench top, and to exhaust 80 CFM per lineal foot of work bench. Usage of 
fully conditioned room air is limited therefore to the differential of 20 
CFM per lineal foot of work bench. 
The open design afforded by the elevation of the hood structure by the 
bipodal support structures 24, and the see-through plexiglass end plates 
20, 21 allow complete work visibility and also allows one supervisor or 
student instructor to monitor several work stations at the same time 
thereby assuring proper safety and economy of operation. 
The system thus has the effect of diluting and extracting fumes caused by 
noxious and odorous reactions at a rate of 80 CFM per lineal foot at a 
cost of only 20 CFM per lineal foot of preconditioned room air. 
Furthermore, since the majority of all particulate matter and reaction 
products are heavier than air, the extraction of such materials along the 
lower horizontal surface is a decided improvement over the equipment 
heretofore available. 
From the foregoing, it is readily apparent that a laboratory work station 
has been herein described and illustrated which fulfills all of the 
aforestated objectives in a remarkably unexpected fashion. It is of course 
understood that such modifications, alterations and adaptations that may 
readily occur to the artisan confronted with this disclosure are intended 
within the spirit of the present invention which is limited only by the 
scope of the claims appended hereto.