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.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates generally to biological safety cabinets and, more particularly, to means and methods for providing users with information related to operational parameters of such biological safety cabinets which may change during ongoing operation. 
         [0002]    Biological safety cabinets provide a biohazard containment means which enable laboratory personnel in diverse industries, e.g., life science, medical, and pharmaceutical industries, to perform various laboratory, experimental and like procedures utilizing biologically hazardous substances while protecting the personnel, the work product and the ambient environment from exposure to and contamination by such substances. Biological safety cabinets are currently certified by the National Sanitation Foundation (NSF) International, of Ann Arbor, Mich., according to three levels of classification. The present invention is described herein in an embodiment adapted to a biological safety cabinet of the type referred to as a Class II cabinet, particularly sub-type A2, but the present invention has broader applicability to all classes and types of biological safety cabinets. 
         [0003]    Class II A2 biological safety cabinets basically have a work chamber that is mostly enclosed except for a front access opening sufficient for a user&#39;s hands to perform procedures within the work chamber. An air circulation system maintains a continuously circulating positive air flow within the work chamber which is controlled to move laminarly in parallel relation to the front access opening to prevent escape of the internal cabinet air outwardly through the forward access opening to protect the user and the ambient area from contamination. The air circulation system utilizes a fan to continuously withdraw air from the work chamber into an adjacent filtration chamber from which a portion of the air is recirculated into the work chamber through a first high efficiency particulate air filter, commonly referred to as a HEPA filter, while the balance of the withdrawn air is exhausted outside the cabinet through a second HEPA filter. Typically, a ratio of about 70% recirculated air to 30% exhausted air is maintained in Class II A2 cabinets. The exhausted air is replaced by ambient air from the surrounding room drawn first into the filtration chamber before entering the work chamber through the first filter, thereby to prevent room air contamination of the work chamber and also to maintain the integrity of the laminar air flow along the front access opening. 
         [0004]    It is important that the filters in such biological safety cabinets be replaced with sufficient frequency to maintain uniformity in the laminar velocity of the circulating air and to minimize airborne contaminants in the circulating air. In turn, therefore, it is important that personnel monitor the degree of loading of the filters with contaminants to be alerted to replace the filters when reaching or approaching a predetermined full condition. It is correspondingly important that personnel continuously monitor the so-called face velocity prevailing within the cabinet, i.e., the velocity of the laminar air flow at the front access opening into the work chamber. 
         [0005]    Various means and devices are available to measure these operational parameters, and other operational parameters of biological safety cabinets. Not only is it important that the sensor and measurement means be reliable and accurate, it is equally important that the relevant information be presented to operating personnel in a clear, organized, intuitive and readily understood format enabling users to quickly assess the status of these operational parameters without diverting attention away from the procedure being performed within the cabinet for any extended period of time. Known conventional biological safety cabinets typically utilize gauges, LED displays and/or monochrome liquid crystal displays that may require a detailed or high level of knowledge of the operation and functioning of the cabinets and are not immediately intuitive to interpret. 
         [0006]    Hence, there is a need in the industry for a form of informational display in biological safety cabinets for presenting operational information to operating personnel in a simple, easily understood and intuitive manner. 
       SUMMARY OF THE INVENTION 
       [0007]    The present invention seeks to address the foregoing needs of the industry, and to overcome the deficiencies of the state of the art, by providing an improved graphical system for displaying information related to one or more operational parameters of a biological safety cabinet that may change during ongoing operation thereof. Basically, the display system comprises a sensor for detecting a prevailing value of a selected operational parameter at least periodically during operation, a display adapted to present a pictorial graphic representative of the prevailing value of the parameter, and a processor associated with the sensor and with the display for controlling the actuation of the display. According to the present invention, the pictorial graphic of the display includes 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. The processor is operative to compare 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. 
         [0008]    The graphical display system of the present invention is susceptible of many and various desirable embodiments. For example, the present display system may be utilized to provide a graphical display representing essentially any operational parameter which may warrant periodic monitoring during ongoing operation of the biological safety cabinet, but typically operational parameters that may be expected to change during ongoing operation of the cabinet and/or parameters whose value provides an indicator of the satisfactory or unsatisfactory operation of the cabinet. One parameter that will typically merit monitoring and display is the degree of contamination loading of an air filter in the biological safety cabinet, which may advantageously be expressed as a percentage of the remaining filter capacity of the filter. Another parameter which is desirable to monitor is the velocity of air flow entering the containment area of the biological safety cabinet. 
         [0009]    The pictorial graphic may be provided with particular features, characteristics and/or capabilities to enhance the recognition and understandability of the display, e.g., the segments of the display may be adapted to illuminate in different colors, such as wherein at least the first segment illuminates in a first color, at least the last segment illuminates in a second color, and at least one of the intermediate segments illuminates in a third color. The graphical display may also include a numerical graphic, with the processor being further operative to cause the numerical graphic to display a numeral corresponding to the prevailing value of the operational parameter. The display may further comprise an audio-visual screen for displaying video content stored in a memory of the processor. The display may also comprise other selectively actuable alert signals. 
         [0010]    In one particularly preferred embodiment, the graphical display system comprises a first sensor for at least periodically detecting a prevailing value of a degree of contamination loading of an air filter in the biological safety cabinet, and a second sensor for at least periodically detecting a prevailing value of air flow velocity circulating within the biological safety cabinet. A first display comprises a first pictorial graphic having a first series of adjacent arcuate segments graphically representing a range of possible values for the contamination loading of the air filter 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 intermediate segments between the first and last segments, and further comprising a first numerical graphic associated with the series of arcuate segments. A second display similarly comprises a second pictorial graphic having a second series of adjacent arcuate segments graphically representing a range of possible values for the air flow velocity 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 intermediate segments between the first and last segments, and further comprising a second numerical graphic associated with the series of arcuate segments. 
         [0011]    In this embodiment, a processor is associated with each of the first and second sensors and with each of the first and second displays. The processor is operative for calculating a percentage of the remaining filter capacity of the filter based upon the prevailing value of the degree of contamination loading of the air filter and selectively illuminating all, none or another number of the segments of the first pictorial graphic to visually signify the remaining filter capacity of the filter. The processor also causes the first numerical graphic to display a numeral corresponding to the percentage of the remaining filter capacity of the filter. The processor is further operative for calcaulating the prevailing value of the air flow velocity circulating within the biological safety cabinet and selectively illuminating all, none or another number of the segments of the second pictorial graphic to visually signify the prevailing value of the air flow velocity. The processor also causes the second numerical graphic to display a numeral corresponding to the prevailing value of the air flow velocity. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  is a partially exploded and partially broken-away perspective view of a biological safety cabinet in which the present graphical display system of the present invention may preferably be embodied; 
           [0013]      FIG. 2  is a vertical cross-sectional view of the biological safety cabinet of  FIG. 1 , taken along line  2 - 2  thereof; 
           [0014]      FIG. 3  is another vertical cross-sectional view of the biological safety cabinet of  FIG. 1 , taken along line  3 - 3  thereof; 
           [0015]      FIG. 4  is a schematic diagram depicting the display system of the biological safety cabinet; and 
           [0016]      FIG. 5  is an elevational view of the graphical display panel of the display system. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0017]    Referring now to the accompanying drawings, and initially to  FIG. 1 , a representative form of biological safety cabinet in which a graphical display system according to the present invention may preferably be embodied is indicated generally at  10 . The safety cabinet  10  basically comprises a housing  12  supported on a trestle stand  14 , which may include a set of casters  16  for moveability of the cabinet structure. The housing  12  is a generally rectangular structure having spaced-apart end walls  18 , a bottom wall  20 , a rear wall  22 , a partial front wall  24 , and a top wall  26 , collectively defining an open interior which is divided by a horizontal intermediate wall  28  into a lower work chamber  30  and an upper air recirculation chamber  32 . The housing  12  may preferably be fabricated of sheet metal, such as stainless steel. 
         [0018]    The partial front wall  24  predominately encloses only the air recirculation chamber  32 , leaving open front access by users into the work chamber  30 . A transparent sash  34  is supported by and extends downwardly from the front wall  24  to partially enclose the work chamber  30  except for a narrow front access opening  36  into the work chamber  30  between the bottom wall  20  and the lower edge of the sash  34  through which users may have manual access into the work chamber  30 . The transparency of the sash  34  permits visual access into the work chamber  30  by users. The sash  34  may also be retractable as necessary to permit greater access into the work chamber  30  by users. 
         [0019]    In  FIG. 1 , the front wall  24  is shown in exploded relation to the remainder of the cabinet  10  for illustration of the air recirculation chamber  32 . As shown in  FIG. 1  and further seen in  FIG. 3 , the majority of the air recirculation chamber  32  is occupied by a hollow sub-housing  40  the open interior of which serves as an air filtration chamber  42 . An air circulation fan  38  is mounted within one end of the recirculation chamber  32  with the output side of the fan  38  mounted to one end of the sub-housing  40  to discharge blown air under positive pressurize into the air filtration chamber  42 . The lowermost bottom side of the sub-housing  40  is open with a first air filter  44  affixed to the sub-housing in covering relation to the opening. Similarly, the uppermost topside of the sub-housing  40  is open with a second air filter  46  affixed to the sub-housing in covering relation to the opening. The two air filters  44 ,  46  are preferably high efficiency particulate air filters, more commonly referred to as HEPA filters, for their ability to capture molecular-sized microorganisms and like biological matter. 
         [0020]    The intake side of the fan  38  draws air from within the work chamber  30  and also from the ambient air surrounding the safety cabinet  10  through hollow interior channels defined within the bottom and rear walls  20 ,  22  of the housing  12 . More specifically, as best seen in  FIG. 2 , each of the bottom and rear walls  20 ,  22  are formed by dual spaced wall panels defining a continuous interior airflow channel  48  within the bottom wall  20  and continuing upwardly within the rear wall  22  to open into the air recirculation chamber  32 . A series of perforations  50  are formed along substantially the full length of the forward edge of the bottom wall  20  to open into the forwardmost end of the airflow channel  48 . A similar series of perforations  52  are formed along the lowermost end of the rear wall  22  adjacent its juncture with the bottom wall  20 , also opening into the airflow channel  48  thereat. 
         [0021]    The housing  12  of the safety cabinet will thus be understood to provide a controlled air recirculation system which operates as follows. The fan  38  continuously creates a negative pressure condition within its end of the air recirculation chamber  32  which acts through the airflow channel  48  to draw air from within the work chamber  30  through the perforations  52  and into the airflow channel  48 . To a somewhat lesser extent, surrounding ambient air is drawn into the airflow channel  48  through the perforations  50 . The fan  38  pressurizes the in-drawn air and discharges it under positive pressure into the filtration chamber  42  from which a portion of the air passes downwardly through the filter  44  into the work chamber and a portion of the air passes upwardly through the filter  46  into an exhaust duct  55 . The filter  44  is of a substantially larger size than the filter  46  such that the majority of the airflow, preferably approximately 70%, returns into the work chamber  30  through the filter  44 , with only a smaller proportion, preferably approximately 30%, of the airflow being exhausted. Within the work chamber  30 , the air passing downwardly through the filter  44  moves predominantly vertically downwardly in a laminar manner which, together with the constraint of the sash  34 , the constraint of incoming ambient air into the perforations  50 , and the negative pressure exerted from the fan through the rearward perforations  52 , substantially prevents the escape of any of the airflow outwardly through the access opening  36 . Thus, users may perform laboratory procedures within the work chamber  30  utilizing hazardous substances, e.g., microorganisms, toxic chemicals, etc., without risking escape of such substances into the ambient area outside the cabinet. Moreover, as such procedures are ongoing, the continuous recirculation of the air internally within the housing  12  progressively filters airborne contaminants so as to maintain sufficient cleanliness within the internal air to prevent contamination of the procedure. 
         [0022]    As will be understood, the filters  44 ,  46  will progressively become loaded with filtered contaminants over time as the cabinet is operated and, as described above, it is important to monitor the degree of filter loading so that the filters may be replaced on a periodic basis. For this purpose, a pressure transducer  54  is positioned within the air recirculation chamber  32  on the intake side of the fan  38  as depicted in  FIG. 4 . The pressure transducer  54  is supplied with operating electrical power from a power supply  61  within a control module  62 , each shown only schematically. The transducer  54  has a first input sensor  56  which is thereby exposed to and senses the prevailing negative pressure within the recirculation chamber  32 . The transducer  54  also has a second input sensor  58  which is connected via a tube  60  through a wall of the sub-housing  40  to be similarly exposed to and to sense the prevailing positive pressure within the filtration chamber  42 . An output connection  64  extends from the transducer  54  back to the control module  62 . The transducer  54  is operative to transmit via the output  64  a variable output voltage proportionate to and thereby representative of the differential in pressure between the negative and positive prevailing pressures sensed by the input sensors  56 ,  58 . 
         [0023]    As will be understood, as the filters  44 ,  46  become progressively loaded with contaminants, the filters impose a greater resistance to airflow through the filters and, in turn, prevailing positive air pressure within the filtration chamber  42  will increase in proportion to the degree of filter loading. On the other hand, the prevailing negative pressure within the air recirculation chamber  32  is essentially unaffected by the loading of the filters. Thus, the overall pressure differential detected by the transducer  54  is proportionally representative of the degree to which the filters are loaded. In turn, monitoring of the progressively increasing pressure differential from the time new clean filters  44 ,  46  are installed is indicative of the progressive loading of the filters. Accordingly, the control module  62  is equipped with a processor, indicated only schematically at  66 , which has a memory and stores operating program logic for computing a quantitative value representative of the contamination loading of the filters  44 ,  46  as a function of changes sensed in the pressure differential over a time period of use of the filters  44 ,  46 . 
         [0024]    For example, the logic stored in the processor  66  may be programmed to calculate a percentage of the remaining filter capacity of the filter based upon changes sensed in the pressure differential over the use of the filters  44 ,  46 . Such calculation may be accomplished in various ways according to various possible algorithms or mathematical computations. In a simplistic algorithm, a first lower pressure differential value may be predetermined, e.g. by actual empirical measurements or by mathematical extrapolation or calculation, to represent a value of 100% filter capacity corresponding to new clean filters  44 ,  46  when first installed, a second higher pressure differential value may be similarly predetermined (by measurement or other means) to represent a value of 0% filter capacity corresponding to a maximum acceptable level of loading of the filters  44 ,  46  at which replacement of the filters is required after a period of use, and the filters may be assumed to become loaded with contaminants during operation at a linear rate for purposes of computing a value signifying the remaining capacity of the filters  44 ,  46  as a percentage of the total filter capacity. Thus, a measured pressure differential at the median value between the first and second pressure differential values is calculated to signify that the filters are 50% loaded and have a 50% capacity remaining. Of course, persons skilled in the art will readily recognize and understand that this simplistic form of algorithm for determining remaining filter capacity is merely one representative illustration. The present invention is not limited to such algorithm. 
         [0025]    As the filters  44 ,  46  become progressively loaded with contaminants, the velocity of air circulating within the work chamber  30  may be affected, particularly as the filters approach their full capacity to hold particulate contaminants. More fundamentally, it is critical to the operational integrity of the biological safety cabinet in preventing the escape of contaminated air into the ambient area surrounding the cabinet and to prevent internal contamination of the procedure being carried out in the work chamber  30  that the velocity of the circulating air be maintained above a minimum threshold and also not exceed a maximum value. Thus, it is also important to monitor the air flow velocity within the work chamber on an ongoing basis. 
         [0026]    The most critical air flow parameter in this regard is the so-called face velocity of the outside air flow entering the biological safety cabinet. For this purpose, a sensor, which may be any suitable form of device capable of accurately measuring the linear speed of the laminar air flow and which is therefore only representatively depicted schematically at  75  in  FIG. 4 , is positioned at any appropriate location at the downstream side of the exhaust air filter  46  suitable for measuring the velocity of the air being exhausted from the cabinet, from which the so-called face velocity of the air flow entering the cabinet may be calculated since the volumes of incoming and exhausted air are equal. The sensor  75  is supplied with operating electrical power via an input lead  76  from the power supply  61  and is connected via an output lead  78  with the processor  66  for transmitting a variable output signal thereto representative of the actual prevailing face velocity of the air flow within the work chamber  30  at the sensor  75 . 
         [0027]    In order for the measured air flow face velocity to have context and to enable personnel to evaluate the acceptability or unacceptability of the prevailing measured value, the memory of the processor  66  stores a range of acceptable face velocity values. Such range may be determined in any of various ways according to differing criteria, e.g., based on experience in operation of biological safety cabinets, or empirical measurements and experimentation. Also, The National Sanitation Foundation (NSF) International has established guidelines for acceptable average face velocities in Class II biological safety cabinets. By way of example only, in the operation of the biological safety cabinet  10 , an acceptable face velocity range has been set between a minimum face velocity of 80 feet per minute and a maximum face velocity of 150 feet per minute, with the preferred range being maintained between 100 and 130 feet per minute. 
         [0028]    The processor  66  is connected to a display panel, indicated only schematically at  68  in  FIG. 4 , which is operative to display a graphical representation of the quantitative value of the remaining filter capacity and the face velocity of air flow prevailing within the biological safety cabinet  10 , enabling the user to constantly monitor the progressive loading of the filters and fluctuations in face velocity as operation of the cabinet is ongoing. The display panel  68  is positioned in a conspicuous and convenient location at the front side of the cabinet  10 , e.g., on the front wall  24  as indicated at  68  in  FIG. 1 . One possible embodiment of the graphical display of the panel is depicted in greater detail in  FIG. 5 . Various programmable display units are currently available in the electronics market, and it is therefore contemplated that a number of available display devices could be utilized as the display panel  68 . For example, one currently available device which has been adapted for use as the panel  68  is the Coldfire® microprocessor Model No. MCF5227x, manufactured and sold by Freescale Semiconductor, Inc., of Austin, Tex. 
         [0029]    As seen in  FIG. 5 , the display panel  68  has three graphical sections, arranged side-by-side, within an overall rectangular flat panel display, which include a “Remaining Filter Capacity” display section  80 , a “Status” display section  82 , and a “Face Velocity” display section  84 . The “Remaining Filter Capacity” display section  80  includes a pictorial graphic  86  formed by a series of adjacent abutting arcuate segments  88  each in the shape of an equilateral circular sector of a semicircular annulus, and with a numerical graphic  90  located in the center area of the annulus. The “Face Velocity” display section  84  similarly includes a pictorial graphic  92  formed by a series of adjacent abutting arcuate segments  94  each in the shape of an equilateral circular sector of a semicircular annulus, and with a numerical graphic  96  located in the center area of the annulus, all in mirror image relation to the “Remaining Filter Capacity” display section  80 . 
         [0030]    The segments  88 ,  94  of the “Remaining Filter Capacity” display section  80  and the “Face Velocity” display section  84  are adapted to be selectively illuminated in differing colors for signifying whether the remaining capacity of the filters  44 ,  46  and the prevailing face velocity within the work chamber  30  of the cabinet  10  are within or outside acceptable values. For example, the color green may be utilized to illuminate segments to indicate an acceptable value, the color yellow may be utilized to illuminate segments to indicate a marginal value, and the color red may be utilized to illuminate segments to indicate a cautionary or an unacceptable value. Thus, the “Remaining Filter Capacity” display section  80  may have a sufficient number of segments  88  to represent a number of percentage increments in the total range of 0% to 100% filter capacity, with associated numerical gradations labeling at least some of the segments  88 , and with the segments  88 A representing the range of 50% to 0% remaining filter capacity illuminated in red, the segments  88 B representing the range of 75% to 50% remaining capacity illuminated in yellow, and the segments  88 C representing the range of 100% to 75% remaining capacity illuminated in green. 
         [0031]    Similarly, the “Face Velocity” display section  84  may have a like number of segments  94  to represent increments in a total range of possible face velocities, including a central group of segments  94 A which are illuminated in green to signify a mid-range of acceptable velocities, adjacent groups of segments  94 B adjacent each side of the central group of segments  94 A which are illuminated in yellow to signify upper and lower marginal ranges of velocities above and below the acceptable mid-range, and outer groups of segments  94 C outwardly adjacent each side of the marginal group of segments  94 B which are illuminated in red to signify unacceptably high and unacceptably low ranges of velocities above and below the upper and lower marginal ranges. Associated numerical gradations label at least some of the segments  94 . 
         [0032]    The “Status” display section  82  may include any of various other informational graphics, legends or alerts, as may be desirable for personnel to monitor the ongoing operation of the cabinet. For example, the “Status” display section  82  may include a video screen  98  which can display text, images, and/or alpha-numeric messages (e.g., “Fan ON”) or play video images. The display panel may also have “touch screen” inputs for enabling users to access from the memory of the processor  66  text, graphical or video content stored in the memory, e.g., an operating or service manual for the cabinet, an instructional or safety video, etc. The “Status” display section  82  may also include dedicated signal alert indicators, such as LED or similar lights  100  adjacent a dedicated informational tag, such as “Sash not 10 inches” and/or “UV Light ON.” 
         [0033]    The operating logic stored in the processor  66  is programmed to operate the “Remaining Filter Capacity” display section  80  and the “Face Velocity” display section  84  based on the respective inputs from the transducer  54  and the velocity sensor  75 , and to operate the “Status” display section  82  according to the intended functionality of the display section  82  and, as necessary or appropriate, based on any other needed sensor inputs. Specifically, the program logic of the processor  66  is operative to calculate the remaining filter capacity of the filters  44 ,  46  as a percentage of the total filter capacity according to the aforementioned algorithm and, in turn, to selectively illuminate, none, some or all of the segments  88  of the “Remaining Filter Capacity” display section  80 , and/or to leave unilluminated or to darken other of the segments  88 , as appropriate to signify graphically the percentage of the remaining filter capacity of the filters  44 ,  46  and thusly, by the colors of the segments alone, to signify whether the remaining capacity is within the acceptable, marginal or cautionary/unacceptable range. At the same time, the program logic of the processor  66  is operative to cause the numerical graphic  90  to display the precise numeral corresponding to the calculated percentage of the remaining filter capacity of the filters. 
         [0034]    At the same time, and in similar manner, the program logic of the processor  66  is operative to calculate the prevailing value of the face velocity of air flow within the biological safety cabinet as sensed by the sensor  75 , and to compare the calculated velocity value against the ranges of values stored in the memory of the processor  66 , to ascertain whether the prevailing face velocity is within the acceptable, marginal or unacceptable range. In turn, the processor  66  is operative to then selectively illuminate, none, some or all of the segments  94  of the “Face Velocity” display section  84 , and/or to leave unilluminated or to darken other of the segments  94 , as appropriate to signify graphically the prevailing face velocity of the air flow within the work chamber  30  and thusly, by the colors of the segments alone, to signify whether the velocity is within the acceptable, marginal or unacceptable range. The program logic of the processor  66  is also operative to cause the numerical graphic  96  to display the precise numeral corresponding to the prevailing air flow velocity as sensed in feet per minute. 
         [0035]    The advantages of the graphical display system of the present invention will this be apparent. The graphical layout and format of the system, and particularly, the use of color and the motion generated by the changing illumination of the pictorial graphics of the display system, provide a user friendly, intuitive and readily understood presentation of information to users, without requiring a high level of special knowledge as to the operational structure and functionality of the biological safety cabinet. The intuitive nature of the display graphics allows users to quickly review the status of the operational parameters being monitored, with minimal diversion of attention away from the procedure that is underway, and also to quickly react to undesirable changes in status when necessary. The ability of the system to store and call up text, video and other content promotes a higher level of safety in the use of the cabinet, and overcomes the potential that relevant manuals and like resources are misplaced, lost or otherwise not readily accessible when needed. 
         [0036]    It will therefore be readily understood by those persons skilled in the art that the present invention is susceptible of a broad utility and application. Many embodiments and adaptations of the present invention other than those herein described, as well as many variations, modifications and equivalent arrangements will be apparent from or reasonably suggested by the present invention and the foregoing description thereof, without departing from the substance or scope of the present invention. Accordingly, while the present invention has been described herein in detail in relation to its preferred embodiment, it is to be understood that this disclosure is only illustrative and exemplary of the present invention and is made merely for purposes of providing a full and enabling disclosure of the invention. The foregoing disclosure is not intended or to be construed to limit the present invention or otherwise to exclude any such other embodiments, adaptations, variations, modifications and equivalent arrangements, the present invention being limited only by the claims appended hereto and the equivalents thereof.