Abstract:
A self-contained closed loop system and method for detecting contaminants in, on, and around objects. The system includes an air duct subsystem connecting at least one sensor to a sealed housing containing a rotating container. Air from the sealed housing is circulated past a sensor to detect, for example, biological or chemical contaminants. If a contaminant is detected, an indicator is set and a contaminant neutralizer is optionally injected into the air duct subsystem.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority to U.S. Provisional Patent Application No. 60/344,848 filed Dec. 31, 2001, entitled CLOSED LOOP SYSTEM FOR AIR SAMPLING OF CONTAINED MAIL PRODUCTS which is incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     This invention relates generally to the containment and detection of hazardous material in a sealed container, and, more particularly to a closed loop system to recirculate air over or through items contained in a sealed container. 
     The recent incidents of anthrax-laced letters flowing through the United States Postal Service (USPS) facilities have alarmed the nation and the world. Currently, the tainted letters are discovered after the recipient accepts delivery or by alert postal employees noticing white powder that could be anthrax on mail parcels, sorting and distribution equipment, or themselves. There appear to be no current security devices or procedures that are available to intercept such letters at the earliest source of introduction into the USPS system, for example at the mailbox or post office drop box. Also, there appears to be no known device or procedure that safeguards against biological agents in powdery forms such as anthrax. 
     Current devices that could detect and safeguard against biological agents can present further problems such as introducing additional contaminants into the air sample that may cause false alarms or shorten the life span of contaminant detection devices. Some current devices are deficient in that they allow the migration of deadly contaminants to the outside environment, or they require the use of costly high efficiency particle air filters (HEPA) filters to process air before release to the outside environment. Some lack the capability to interject a contaminant neutralizer into a sealer container when a contaminant has been detected. 
     A system is needed in which detection and neutralization of mail- and parcel-born contamination can happen in a closed environment without manual intervention. 
     SUMMARY OF THE INVENTION 
     The problems set forth above as well as further and other problems are solved by the present invention. The solutions and advantages of the present invention are achieved by the illustrative embodiment of the present invention described hereinbelow. 
     The present invention is a self-contained closed loop system and method for detecting contaminants in and around objects, including mail pieces and parcels, and neutralizing the environment containing the contaminants. The system of the present invention includes, but is not limited to, a housing such as a cabinet, a perforated container, an air duct subsystem, a power subsystem, a sensor subsystem, an indicator subsystem, and a controller. Optionally, the system of the present invention can include a blower subsystem and a neutralization mechanism. 
     The housing creates an enclosure and forms an airflow barrier between the enclosure and the outside ambient air. The housing has a housing opening for inserting and removing the object(s). The container forms a cavity for holding the object(s). The container has a shell with at least one perforation and is rotatably mounted within the housing. The container has at least one container opening for inserting and removing the object(s). The power subsystem, operably connected to the container, rotates the container. 
     The sensor subsystem tests an air stream for contaminants. The indicator subsystem is operably connected to the sensor subsystem and provides a signal when at least one contaminant is detected. 
     The air duct subsystem is capable of ducting the air stream in a closed loop throughout the system. The air duct subsystem can duct the air stream into a perforated pipe that is mounted within the container. The perforated pipe allows the air stream to enter the cavity, and the perforation(s) in the cavity allows the air stream to enter the enclosure. The air duct subsystem can receive the air stream from the enclosure and can duct it past the sensor subsystem and back through the housing into the container, optionally forced by the blower subsystem. 
     The controller sequences operations among the sensor subsystem and the power subsystem so that particles that can be emitted while the object(s) are being tumbled within the cavity when the container is rotating. The particles can pass through the perforation(s) in the container from the cavity to the housing and then are entrained with the air stream into the air duct subsystem. The air stream and particles exit the housing and are ducted past the sensor subsystem which sends a signal to the indicator subsystem if contaminant(s) is detected in the particles. 
     Optionally, the blower subsystem can force the air stream through the air duct subsystem. If a blower subsystem is used to force the air stream, the controller can sequence activities among the blower subsystem, the sensor subsystem, and the power subsystem. Also optionally, when contaminant(s) is detected, a neutralization mechanism can inject a conventional contaminant neutralizer such as chlorine-calcium, formalin, or lye solutions into the air stream in the air duct subsystem. If a neutralization mechanism is used, the controller can sequence activities among the neutralization mechanism, the sensor subsystem, and the power subsystem, and optionally the blower subsystem. 
     The method of the present invention includes the steps of loading a perforated container with at least one object, enclosing the perforated container within a housing, and sealing the housing. In this method, the step of sealing forms an ambient air barrier which prevents air and particles emitted from the perforated container into the housing from entering the ambient air outside the housing. The method of the present invention further includes the step of rotating the perforated container. Rotation of the perforated container that contains objects can serve to release particles that are on and in the objects within the perforated container into an air stream that entrains emitted particles. The method further includes the step of sampling the air stream that enters the housing through the perforations in the container. The method includes the steps of testing for at least one contaminant and providing an indicator if at least one contaminant is detected. The method can optionally include the steps of forcing air into the rotating perforated container, which in turn is forced through the perforations into the housing, and introducing a neutralizing agent into the air stream if the air stream contains at least one contaminant. 
     For a better understanding of the present invention, together with other and further objects thereof, reference is made to the accompanying drawings and detailed description. The scope of the present invention is pointed out in the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         FIG. 1  is a schematic block diagram of the components of the system of the present invention; 
         FIGS. 2A and 2B  are flowcharts of the method of the illustrative embodiment of the present invention; 
         FIG. 3  is a pictorial representation of the illustrative embodiment of the system of the present invention; 
         FIG. 4  is a pictorial representation of a front view of the illustrative embodiment of the system of the present invention; 
         FIG. 5  is a pictorial representation of a rear view of the illustrative embodiment of the system of the present invention; 
         FIG. 6  is a pictorial representation of a front view of the open housing and container of an alternate embodiment of the housing stand of the present invention; 
         FIG. 7  is a pictorial cut-out representation of a rear view of the interface board and perforated container within the housing of the illustrative embodiment of the present invention; 
         FIG. 8  is a pictorial cut-out representation of a front view of the perforated container and interface board of the illustrative embodiment of the present invention; 
         FIG. 9  is a pictorial representation of a second alternate embodiment of the present invention in which the sensors and indicator are directly sensing the air stream in the housing; and 
         FIG. 10  is a pictorial representation of a third alternative embodiment of the present invention in which the blower, sensors, and indicator, are blowing an air stream directly into the housing and directly sensing the air stream in the housing respectively. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention is now described more fully hereinafter with reference to the accompanying drawings, in which the illustrative embodiment of the present invention is shown. 
     System  10  of the present invention, shown in  FIG. 1 , includes, but is not limited to, a sealed housing  107  forming an enclosure, the enclosure containing a perforated container  109  forming a cavity, a sensor subsystem  105 , and an indicator subsystem  113 . Optionally, system  10  can include a blower subsystem  101 . Components  101 ,  105 , and  107  are in airflow communication through air duct subsystem  103 . In addition, a power subsystem  111 , an optional neutralization mechanism  115 , and a controller  117  complete system  10 . 
     In operation, perforated container  109  is rotated by power subsystem  111  while optional blower subsystem  101  forces an air stream through air duct subsystem  103 . When perforated container  109  is loaded with objects, such as mail pieces and/or parcels, and rotated, any loose particles that are on or in the objects can be released. These particles can eventually be forced into the enclosure formed by the sealed housing  107  through the perforations in perforated container  109  by the pressure of air flowing into the perforated container  109  and by the container&#39;s centrifugal force. The particles can then be entrained into the air stream that is flowing into sealed housing  107  from the perforations in perforated container  109 . This air stream is ducted by the air duct subsystem  103  past sensor subsystem  105  where it is tested by conventional sensor equipment such as the BIONI or Biological Aerosol Real Time Sensors manufactured by Pacific Scientific Instruments and the Biological Aerosol Warning Systems I, developed by the assignee of this application, or any cost-effective, real-time sensor for airborne biological particles or other contaminants. If contaminants are detected, indicator subsystem  113  provides an indication of the presence of contaminants. Optionally, neutralization subsystem  115  can operate cooperatively with the sensor subsystem  105  to neutralize the air stream. Controller  117  can sequence operations among the various subsystems, for example, activation and deactivation of the blower subsystem  101  and the power subsystem  111 . 
     Referring now to  FIG. 2A , the method of the present invention includes the step of loading a perforated container with objects and closing the container (method step  201 ). The method further includes the steps of enclosing the perforated container within a housing and sealing the housing to prevent gas exchange between the air inside the housing and the air outside the housing (method step  203 ). The method of the present invention next includes the step of rotating the perforated container and the objects within the perforated container so that any particles that might on or in the objects are shaken loose by the rotation and emitted into an air stream surrounding the objects within the container (method step  205 ). The method further includes the steps of sampling the air stream by the sensors for the presence of contaminants (decision step  209 ), and setting an indicator if at least one contaminant is detected (method step  211 ). 
     Referring now to  FIG. 2B  optional steps that can be taken if the air stream contains contaminant(s) include introducing a conventional neutralizing agent into the air stream if at least one active contaminant is detected (method step  213 ) to neutralize the air stream. The method includes the further step of stopping the system and taking actions to make the workplace safe and to isolate contaminated objects (method step  215 ). If the air stream is found to be free of contaminants, the method of the present invention includes the final steps of stopping and unloading the perforated container (method step  217 ). 
     Referring now to  FIG. 3 , system  10  of the illustrative embodiment of the present invention includes housing  13  with housing lid  21  mounted on housing stand  31 . In the illustrative embodiment, the housing can be predominately 16–18 gauge stainless steel or any material to allow for corrosion resistance and internal sanitization if necessary. An external framework of powder-coated steel or any other type of material can be used for supporting the housing. The housing can be any size, and could be specially constructed to accommodate certain sizes of objects or areas of application. For example, if the system is to be used primarily in a mailroom, that application could require a relatively large housing to accommodate packages that might be entering the mailroom. On the other hand, if the system were primarily for home use, the housing could be quite small, if desired, to accommodate analysis of flat letters only, for example. 
     Continuing to refer to  FIG. 3 , the housing lid  21  is preferably, although not necessarily, a lift-open glass door operably connected to the housing  13  by lid hinges  48  (shown in  FIG. 6 ). System  10  also includes conventional sensors  17  which are, in the illustrative embodiment, a particle sensor and a biological agents sensor, the complementary action of which enhances contaminant detection possibilities. The particle sensing system, illustratively the BAWS I system, is specially suited to detect particles in the 2–10 micron range favored for aerosol dispersion of biologic agents. The biological agents sensor, illustratively the BAWS III sensor, utilizes ultra-violet laser fluorescence technology to analyze captured particles for the presence of biological agents. In the illustrative embodiment, the two sensors can be coupled together by an RS-232 communications line, or any other appropriate electronic communications mechanism. The particle sensor can communicate with a controller  11  through an RF link to the RF radio network or any other suitable means of wired or wireless electronic communications. Note that any sensors, including but not limited to chemical, biological, and particle, can be used in the system of the present invention. 
     Continuing to refer to  FIG. 3 , controller  11 , which can be a personal computer, a programmable logic controller, or other such device, is operably connected to interface panel  44  (shown in  FIG. 5 ). In the illustrative embodiment, controller  11  is a personal computer with a Universal Interface Unit for connecting external sensors and an RF network radio. The personal computer of the illustrative embodiment operates under Windows NT, but can operate under any operating system that supports the appropriate hardware and software to interface with and control the various components of the system. Application software to control system  10  is standard BAWS sensor software with upgrades as follows: (1) a new communications message format is added to accommodate information from the sensors of system  10 , and (2) the software is modified for non-military use. Any application software appropriate for the sensors selected for the system can be used. 
     Continuing to refer to  FIG. 3 , system  10  can also contain a visual indicator  15 , an illustrative embodiment of the indicator subsystem  113 , that can be color-coded to indicate contamination states. System  10  also includes a rear housing door  19  through which the operator can access the interface panel  44  but which does not allow gas exchange with the air-sealed environment of the housing  13 . System  10  also can optionally include discharge handle  25  and discharge receptacle  27 . Discharge handle  25  can be pressured manually to release objects from the container  55  (shown in  FIG. 6 ) and housing  13  into discharge container  27 , which can be any container suitable for the weight and size of the objects being tumbled in container  55 . The handle  25  and housing  13  are operably connected by an interlocking conventional mechanical linkage having a conventional camming feature that reliably seals the discharge hatch lid  35 . The conventional interlocking mechanism insures that so that the housing  13  is incapable of being opened during use. It&#39;s envisioned that this could be used manually or could be run off the control system and could a pneumatically- or electrically- or hydraulically-controlled, so manual intervention is required. In the illustrative embodiment, an optional loading ramp  29  is shown, having ramp rails  23  and leading to the housing  13 . The loading ramp  29  can aid in transporting objects to and loading objects into housing  13 . 
     Referring primarily now to  FIG. 4 , a front view of the housing  13 , housing stand  31  and controller  11  are shown. In the illustrative embodiment, controller stand  60 , mounted on controller shelf support  59 , is operably connected to housing  13  and housing stand  31 . Controller  11  can be located any distance from housing  13 , but must have electronic (wired or wireless) connection with interface board  44  (shown in  FIG. 5 ). Also shown is control panel  37  which, in the illustrative embodiment, is a panel with start, stop, load/unload, and emergency stop buttons. Also shown are housing lid latches  18  that insure that the housing is sealed against gas exchange with the ambient workspace. Also shown are housing recess  33  and housing discharge lid  35 . Housing recess  33  is formed to allow free rotation of container  55 . Housing discharge lid  35  is operably connected to handle  25  such that when handle  25  is depressed, after housing discharge lid  35  is opened and the removable lid (not shown) is removed from container  55 , container  55  rotates into discharge position and the objects within container  55  drop into receptacle  27 . 
     Referring now to  FIG. 5 , a rear view of housing  13 , housing stand  31 , and interface panel  44  are shown. In the illustrative embodiment, interface panel  44  includes electronics to provide the interface between controller  11  and operational subsystems of the system of the present invention. For example, controller  11  allows the operator to stop the rotation of container  55  through a push-button on control panel  37 . Interface panel  44  contains electronics to disable power to motor  41 , which thus disables rotation of container  55  (the coupling of motor  41  to the rotation of container  55  is shown in  FIG. 8 ). 
     Continuing to refer to  FIG. 5 , rear housing wall  45 , along with interface panel  44 , complete the rear sealed housing. Interface panel  44  is covered during operation by rear door  19  which can be operably connected to the housing  13  by rear hinges  38  and latched in place by latch  39 . Shown also is a pipe of the air duct subsystem  43 . This part of the piping ducts air from the housing  13  to the recirculation blower  63  (shown in  FIG. 7 ). 
     Referring now to  FIG. 6 , an alternate embodiment  20  of the system of the present invention shows a housing stand in which the housing  13  is supported by attached legs  51  and housing support connectors  53 . Also shown (and the same in both illustrative and alternate embodiments) is the perforated container  55  and cavity  57 . 
     Referring now to  FIG. 7 , a rear view of interface panel  44  and container  55  are shown with the housing removed. Container  55 , which can be any shape, is six-sided in the illustrative embodiment. It has a removable lid (not shown, attached conventionally when in place) which, when opened, can admit objects into container  55  to be tumbled. Once loaded, container  55 , perforated with one or more perforations  67 , can be rotated to tumble the objects and agitate them. The preferred rate of rotation is sufficient to tumble the objects in container  55 , but not so fast that the objects are pinned to the sides of container  55 , thus preventing agitation. The air duct subsystem  43  directs an air stream at the objects within the container by means of a perforated air pipe  83  (shown in  FIG. 8 ) that also acts as an axle to the rotating container  55 . Air pipe  83  is in airflow communication with the air duct subsystem  43  which junctions with air pipe  83  at intersection  69 . Rotating coupling  71  provides a rotatable connection between the air duct subsystem  43  and the container  55  by allowing the air stream to flow through the coupling  71  while the coupling  71  and the container  55  rotate. Container  55  is attached to housing  13  on one side by air duct housing mounting connection  77 . 
     Continuing to refer to  FIG. 7 , motor sprocket  73  which drives, for example, a chain, belt, or direct drive that acts as a container rotation means to rotate the container  55  is shown. Also shown is recirculating blower  63  which forces the air stream through the air duct subsystem  43 . It can be seen that air leaving container  55  at exit port  65  passes sensor probes  61  on its way to recirculation blower  63 . As long as power is supplied to the system, recirculation blower  63  forces the air stream back through interface panel  44  at air duct housing entry  75  and into container  55  at rotating coupling  71 . If contamination is detected by conventional sensors  17  through air stream sampling by sensor probes  61 , a signal is sent to the indicator subsystem and to controller  11  through interface panel  44 . 
     Referring now to  FIG. 8 , a front view of container  55  is shown with the housing removed. In this view, container sprocket  87  and chain or belt  81  are shown. Motor  41  (shown in  FIG. 7 ) drives the rotation of motor sprocket  73  and thus drives chain  81  and container sprocket  87  to rotate container  55 . Container  55  is connected to housing  13  on the motor side by chain or belt drive housing mounting connection  79 . Air duct junction  85  is shown by which the air stream is provided by the recirculation blower  63  at air duct housing entry  75  (shown in  FIG. 7 ). 
     Referring now to  FIG. 9 , second alternate embodiment  30  is shown in which conventional sensors  17  directly sample air inside recessed (reference number  33 ) housing  13  and provide a first signal to indicator  15  if at least one contaminant is detected. System  30  further includes container  55  which is a six-sided perforated (reference number  67 ) container that forms cavity  57 . Cavity  57  is loaded with objects and then closed as a lid (not shown) is positioned atop container  55 . After the objects are loaded, housing lid  21  is shut to prevent gas exchange between the air within housing  13  and the ambient air. Container  55  is rotated by any kind of conventional power supply (not shown), thus tumbling the objects within cavity  57  and perhaps releasing particles associated with the objects into the air in the cavity  57 . Air and particles mix and exit cavity  57  through perforations  67  into the enclosure formed by housing  13  where the air and particles are tested for contamination by conventional sensors  17 . 
     Referring now to  FIG. 10 , third alternate embodiment  40  in shown which is the same as alternate embodiment  30  except that a conventional blower  89 , operably connected to housing  13 , forces air into housing  13 . The forced air can increase air circulation into container  55  and conventional sensors  17 , thus potentially increasing the frequency and reliability of contaminant detection by conventional sensors  17 . 
     Although the invention has been described with respect to various embodiments, it should be realized this invention is also capable of a wide variety of further and other embodiments within the spirit and scope of the appended claims.