Note: Descriptions are shown in the official language in which they were submitted.
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APPARATUS FOR SCREENING MAIL FOR HAZARDOUS SUBSTANCES
BACKGROUND
[0001] The present invention relates to a mail screening apparatus and, more
particularly, to a mail screening apparatus that can be used to screen mail
for
hazardous agents.
[0002] Individuals bent on harming others and disrupting society have
demonstrated
that hazardous biological agents, such as anthrax in micron-sized particles,
can be
spread in envelopes or parcels delivered through the postal system. The
particles are
dispersed when mail is sorted by mail personnel or equipment or when the
envelope
or parcel is opened by the recipient. For example, in October 2001, anthrax
was
discovered in mail processed by the United States Postal Service in
Washington, D.C.
The resulting contamination caused serious illness to postal employees and at
least
one death. The incident also disrupted the flow of mail, caused economic loss,
resulted in the closure of postal facilities and offices of the United States
Congress,
and generated fear among postal/mailroom workers and the general population.
[0003] Existing mail screening systems typically sound an alarm once a
dangerous
level of anthrax is detected in mail. The suspect mail is then quarantined to
limit
contamination and protect mail handlers and recipients. However, existing mail
screening systems are not sufficiently accurate. For example, conventional
mail
screening systems may result in an unacceptably high number of false positives
(i.e.,
falsely indicating the presence of a dangerous level of a biological agent)
and false
negatives (i.e., falsely indicating the absence of a dangerous level of a
biological
agent). A false positive could cause unnecessary expense and disruption
including
building closure, medical quarantine, medical treatment, and public panic.
Conversely, a false negative could result in failure to detect and contain
contaniination, which could lead to widespread contamination and serious
illness
and/or death to those infected by the biological agent. Additionally,
decontamination
costs could be exceedingly high.
[0004] Another disadvantage of conventional mail screening systems is that
such
systems are too slow to enable rapid and cost-effective management of a
potential
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anthrax release. For example, existing systems do not enable near-real time
detection
and may require more than an hour to obtain and analyze a sample for the
presence of
anthrax.
[0005] Another disadvantage of conventional mail screening systems is that
such
systems remove an excessive amount of material from or otherwise deface a mail
item
to obtain a sample of the contents of the mail item. Thus, the confidentiality
and
appearance of the screened mail are compromised. For example, some mail
screening
systems remove the corners of an envelope, cut visible holes in the envelope,
or
completely slice open the envelope to collect a sufficient sample size. Such
systems
may also force air across the envelope or subject the envelope to vibration to
capture
the sample, which may contaminate the sample. Additionally, conventional
systems
have a limited ability to screen mail of various sizes. For example, such
systems may
be able to screen envelopes but not thicker parcels or boxes.
[0006] Moreover, existing mail screening systems are not equipped to detect
threats
other than anthrax, such as other biological agents, chemical agents,
explosive agents,
radioactive agents, and narcotic agents. A need to detect various types of
threats
exists. For example, a postal attack in Belgium in June 2003 involved a
chemical
agent and resulted in hospitalization of several individuals. The contaminant
included
a yellow powder that was an arsenic derivative typically used in nerve agents.
SUMMARY OF THE INVENTION
[0007] An embodiment of the present invention relates to a screening
apparatus.
The screening apparatus includes an access -device configured to create an
opening in
a mail item and a pressurizing device configured to increase an internal
pressure of
the mail item so that the pressure is released through the opening. The
screening
apparatus also includes a sampling device configured to receive a sample of an
interior environment of the mail item when the pressure is released through
the
opening and a detection device configured to analyze the sample to detect the
presence of a hazardous agent.
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BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The accompanying drawings, which are incorporated in and constitute a
part
of this specification, illustrate an example of the invention and together
with the
description serve to explain the principles of the invention.
[0009] Figure 1 is a perspective view of an embodiment of a screening
apparatus
according to the present invention.
[0010] Figure 2 is a front perspective view of the screening apparatus of Fig.
1 with
lower doors in an open position.
[0011] Figure 3 is a perspective view of detail A in Fig. 1 with some cover
panels
removed.
[0012] Figure 4 is a front elevation view of a cutting device and a guide
roller of the
screening apparatus of Fig. 1.
[0013] Figure 5 is a front elevation view of the cutting device and guide
roller of
Fig. 4 showing processing of a mail item.
[0014] Figure 6 is a top plan view of the mail item of Fig. 5.
[0015] Figure 7 is a perspective view of detail A in Fig. 1 with additional
cover
panels removed.
DETAILED DESCRIPTION
[0016] Referring to Figures 1 through 3, the screening apparatus 10 generally
includes an access device 20, a pressurizing device 30, a sampling device 40,
and a
detection device 50.
[0017] The access device 20 is configured to receive a mail item 15, such as
an
envelope, and to deliver the mail item 15 to the pressurizing device 30. The
mail item
15 can be introduced to the access device 20 automatically. For example, the
access
device 20 can include an intake device 23 (shown in Fig. 1) having a conveyor
mechanism 23a configured to feed the mail item 15 into the access device 20.
The
mail item 15 can be placed flat on the intake device 23 and advanced through
the
access device 20 by the conveyor mechanism 23a.
[0018] The access device 20 can also be configured to create an opening 15a in
the
mail item 15 (shown in Fig. 6). The opening 15a provides access to an interior
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environment of the mail item 15 so that a sample of the interior environment
(or
contents) can be forced through the opening 15a by the pressurizing device 30.
The
sample can then be collected by the sampling device 40 and analyzed by the
detection
device 50. Alternatively, the access device 20 can be configured so that the
access
device 20 does not cut or open the mail item 15 in any manner. When the access
device 20 does not cut or open the mail item 15, the sample can be extracted
through
pre-existing openings in the mail item 15, such as unsealed corner portions of
an
envelope.
[00191 If an opening 15a is desired, the access device 20 can include a
cutting tool
25 (shown in Figs. 4 and 7) for creating the opening 15a. The cutting tool 25
can
have various configurations. For example, the cutting too125 can comprise a
circular
disk having a plurality of blades 25a (e.g., eight blades 25a) disposed along
a
periphery of the disk, as shown in Fig. 4. The blades 25a can have a width W
and can
be disposed so that a center point of each blade 25a is located at an angle 0
from a
center point of a consecutive blade 25a. The width W can be, for example,
approximately 0.14 inches, and the angle 9 can be approximately 45 degrees.
Each
blade 25a can create an opening 15a, such as a slit, on a face of the mail
item 15. As
shown in Fig. 6, the opening 15a is very narrow. Thus, the blades 25a can
create
openings 15a in the mail item 15 without removing a substantial amount of
material
from the mail item 15.
[0020] The access device 20 can also include a guide roller 27 (shown in Figs.
4 and
7) to control and facilitate movement of the mail item 15 through the access
device
20. The guide roller 27 can be disposed above the cutting too125 so that the
mail
item 15 is received between the cutting too125 and the guide roller 27, as
shown in
Fig. 5. The guide roller 27 maintains a distance D between the guide roller 27
and an
edge of the cutting too125 to control formation of the opening 15a and to
enable the
access device 20 to receive mail items 15 of varying thickness. For example, a
mail
item 15 can have a thickness of approximately 1/4 inch or less. If the
distance D is
too great, the opening 15a may not be large enough to force a sample of the
contents
of the mail item 15 through the opening 15a. Conversely, if the distance D is
too
small, the cutting too125 may tear the mail item 15 or remove a noticeable
amount of
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material from the mail item 15. The distance D may be, for example,
approximately
0.005 inches.
[0021] The pressurizing device 30 is configured to receive the mail item 15
from the
access device 20 and to compress the mail item 15 to force a sample of the
contents
through the opening 15a (or through pre-existing openings). For example, the
pressurizing device 30 can be disposed adjacent to the access device 20 so
that the
conveyor mechanism 23a automatically feeds the mail item 15 into the
pressurizing
device 30. The pressurizing device 30 includes a compression member 35 (shown
in
Fig. 7) configured to continuously compress the mail item 15 to increase the
internal
pressure of the mail item 15 as the mail item 15 moves through the compression
member 35. For example, the compression member 35 can include a first roller
35a
and a second roller 35b, as shown in Fig. 7. The first roller 35a can be
disposed
above the second roller 35b so that a central axis A-A of the first roller 35a
is
substantially parallel to a central axis B-B of the second roller 35b. The
first and
second rollers 35a, 35b can be disposed substantially transverse to a
direction of
advancement of the mail item 15. Thus, the mail item 15 can be received
between the
first and second rollers 35a, 35b. As the first and second rollers 35a, 35b
rotate, the
mail item 15 advances through the compression member 35 so that the first and
second rollers 35a, 35b compress a first portion (or first end) of the mail
item 15, then
compress a middle portion of the mail item 15, and then compress a second
portion
(or second end) of the mail item 15.
[00221 The first and second rollers 35a, 35b can be moveable relative to one
another
to enable the compression member 35 to receive mail items 15 of varying
thickness.
Additionally, a length of the first and second rollers 35a, 35b can be
selected so that
the compression member 35 can receive mail items of varying dimensions. For
example, the mail item 15 can have a length of up to approximately 12 inches
and a
width of up to approximately 12 inches. The pressurizing device 30 can also be
configured to automatically deposit the compressed mail item 15 into a storage
bin 27,
such as a mail cart, stored within the screening apparatus 10 and accessible
via a door
5, as shown in Fig. 2. For example, the storage bin 27 can be disposed below
an end
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of the pressurizing device 30 so that the mail item falls into the storage bin
27 when
the mail item 15 exits the compression member 35.
[0023] In operation, the sample of the contents of the mail item 15 is
extracted as
the mail item 15 traverses the pressurizing device 30. For example, pressure
can build
up within the mail item 15 as the mail item 15 advances through the
compression
member 35 and undergoes compression. When a sufficient amount of pressure has
developed, the pressure bursts through the opening 15a (or through pre-
existing
openings) thereby releasing a sample of the contents of the mail item 15. The
sample
is then available for collection by the sampling device 40.
[0024] The opening 15a is configured to enable adequate pressure to develop
and to
allow a sample of sufficient size to be released. For example, the opening 15a
can
comprise a substantially straight cut, slit, or perforation or a plurality of
cuts, slits, or
perforations disposed in a substantially straight line, as shown in Fig. 6. A
length Lo
of each opening 15a must be large enough to release a sufficient sample size
but small
enough to allow pressure to develop within the mail item 15. For example, the
length
Lo of an opening 15a may be in a range of approximately 1/8 to 1/4 inch.
[00251 Similarly, the openings 15a must be sufficiently spaced apart to allow
adequate pressure to develop within the mail item 15. For example, a distance
Do
between an end of a first opening 15a and a beginning of a subsequent opening
15a
may be in a range of approximately 1 to 1.5 inches. Thus, the relationship
between
the length Lo and the distance Do can determine whether a sufficient sample is
released. For example, a ratio of the length L. and the distance Do may be
approximately 1:12 to 1:4 (preferably 1:8 to 1:6).
[0026] Additionally, although the openings 15a shown in Fig. 6 are disposed
below
an edge of the first mail item 15, it will be recognized that the openings 15a
could be
located at various locations on the mail item 15. In this manner, the access
device 20
can create an opening 15a so that a sufficient sample size is released without
significantly defacing the mail item 15 or compromising the confidentiality of
the
mail item 15. Moreover, the openings 15a are a discrete visual mark on the
mail item
15 that can be used to verify that the mail item 15 has been screened.
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[0027] The sampling device 40 is configured to collect (or receive) the sample
when
the pressure within the mail item 15 is released through the opening 15a (or
through
pre-existing openings). For example, the sampling device 40 can include an air
collection hose 42 (shown in Figs. 3 and 7) with an intake opening disposed
between
the access device 20 and the pressurizing device 30. The air collection hose
42 can be
operatively connected to a vacuum device so that a suction force is created at
the
intake opening. When the pressure is released through the opening 15a (as
discussed
above) the suction force draws the sample into the air collection hose 42. The
sampling device 40 can be controlled to maintain a desired air flow rate. For
example, the air flow rate can be approximately 450 liters per minute.
[0028] Once the sample is collected, the sample can optionally be converted to
a
liquid sample using a conversion device, such as a Spincon concentratr. The
sample
is automatically delivered to the detection device 50 using a pumping device.
In this
manner, the sampling device 40 can obtain a sample of the contents of the mail
item
15 without subjecting the mail item 15 to vibration and without forcing air
over the
mail item. Thus, the potential for contamination of the sample is reduced.
[0029] The screening apparatus 10 can also include a second access device 60
(shown in Fig. 1) configured to create an opening in a mail item 17 when the
mail
item 17 is too large to be processed through the access device 20 and the
pressurizing
device 30. Thus, the second access device 60 can be used to create an opening
in a
mail item 17 having a thickness greater than 1/4 inch, such as a box or a
package. For
example, the mail item 17 can have a length of up to approximately 13 inches,
a width
of up to approximately 13 inches, and a height of up to approximately 13
inches.
[0030] The second access device 60 can be configured for manual operation. For
example, the mail item 17 can be placed into a manual screening area 62 of the
screening apparatus 10 by an operator The manual screening area 62 can be an
open
area within the screening apparatus 10 large enough to receive the mail item
17, as
shown in Fig. 1 The operator manually opens the mail item 17 and can examine
the
contents of the mail item 17 for sealed items, such as letters or other closed
items. A
sample of the interior of the mail item 17 can be obtained using the sampling
device
40, wlzich can include a second air collection hose 47 (shown in Fig. 2). The
operator
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collects the sample by manually maneuvering the hose 47 near and/or within the
interior of the mail item 17. As discussed above, the sampling device 40
evacuates
the sample and delivers the sample to the detection device 50. The operator
then
reseals the mail item 17 and moves the mail item 17 into a package cabinet 65
through
an aperture 67. The mail item 17 is stored in the package cabinet 65 until
processing
of the sample by the detection device 50 is complete (or until a full
screening cycle is
complete). In this manner, the screening apparatus 10 can be used to screen
both
large and small mail items.
[0031] The detection device 50 is configured to analyze samples of the
contents of
the mail items 15, 17 to determine whether a hazardous agent is present in the
samples. The detection device 50 can include, for example, portable detectors,
such
as Smiths APD 2000 and Saber 2000; an ion scan mobility system; and/or a
polymerase chain reaction (PCR) instrument, such as GeneXpert or Bio-Seeq. If
a
PCR instrument is used (to screen for a biological agent), particles in the
sample are
first concentrated into a liquid sample and then transferred to a disposable
cartridge.
The cartridge is analyzed using PCR technology to detect the presence of the
biological agents. Through the completely automated PCR process, one molecule
of
Deoxyribonucleic Acid (DNA) is replicated up to approximately a billion-fold,
which
provides sufficient genetic material for detection and positive
identification. The time
for a result from a PCR test can be, for example, approximately thirty
minutes,
compared to several days for a conventional lab culture. Additionally, PCR
technology possesses excellent sensitivity and has the ability to detect a
single
bacterial cell.
[0032] If the detection device 50 obtains a negative result (i.e., indicates
the absence
of a dangerous level of a hazardous agent), the mail items 15, 17 can be
unloaded
from the screening apparatus 10 and re-introduced into the general mail
population
and flow. If the detection device 50 obtains a positive result (i.e.,
indicates the
presence of a dangerous level of a hazardous agent), an alarm can sound and a
paging
device can be activated to notify essential personnel. The screening apparatus
10 can
then be secured and the suspect mail items 15, 17 quarantined. Upon
quarantine, first
responder personnel can, for example, visually inspect each mail item for
unusual
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markings or other indications that a particular mail item is the source of the
hazardous
agent. Additionally, due to cross contamination, mail items other than the
source item
are likely to have traces of the hazardous agent. Thus, the entire batch of
quarantined
mail items can be treated as dangerous.
[0033] The detection device 50 can be configured to detect a biological agent,
such
as anthrax. Additionally, it will be recognized that the capabilities of the
detection
device 50 can be expanded to detect hazardous agents other than anthrax. For
example, the detection device 50 could be configured to detect other
biological
agents; chemical agents, including nerve and blister agents such as Tabun,
Sarin,
Soman, Cyclosarin, Agent VX and Vx, and Nitrogen Mustard; radioactive agents;
narcotic agents; and explosive agents, such as RDX, PETN, TNT, Semtex, NG, and
Ammonium Nitrate.
[00341 When the detection device 50 is configured to detect explosive agents,
the
screening apparatus 10 can further include a pre-screening X-ray device to
detect the
explosive agent (or explosive device) in a mail item 15, 17 before the mail
item 15, 17
is processed through the screening device 10. The X-ray device can be, for
example,
Smiths Heimmann Model 7555. Thus, potential detonation of the explosive agent
during processing in the screening apparatus 10 is avoided. For example, the X-
ray
device can be disposed prior to the intake device 23 so that the mail items
15, 17 can
be x-rayed before being introduced into the access device 20 or the second
access
device 60. If the presence of an explosive agent is detected by the X-ray
device, an
alarm can sound and the screening apparatus 10 can be secured so that the
suspect
mail item 15, 17 is not introduced into the access device 20 or the second
access
device 60. In this manner, the potential for detonation of the explosive agent
during
processing in the access device 20, the second access device 60, or the
pressurizing
device 30 is reduced.
[00351 The screening apparatus 10 can also include a protective enclosure 70
that
can be configured to be maintained at a negative pressure. For example, the
protective enclosure 70 can include an exhaust system disposed in an upper
portion
l0a of the screening apparatus 10. The exhaust system can comprise an air
handler
including a filter to capture aerosolized contamination and to prevent such
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contamination from being released into the environment surrounding the
screening
apparatus 10. For example, the filter can comprise a high efficiency
particulate air
filter and/or a carbon filter. When the access device 20, the pressurizing
device 30,
the sampling device 40, the detection device 50, the second access device 60,
and/or
the sealed package cabinet 65 are disposed within the protective enclosure 70,
the
potential for contamination external to the screening apparatus 10 is reduced.
[0036] In operation, multiple mail items 15, 17 can be processed during one
cycle of
the screening apparatus 10. Cycle process time (i.e., a time from mail loading
to mail
unloading) can be, for example, approximately one hour. The mail items 15, 17
are
loaded into the screening device 10. For example, an operator can manually
place a
mail item 17 into the manual screening area 62 of the second access device 60.
The
operator manually opens the mail item 17 and evacuates a sample from the
interior of
the mail item 17 using the air collection hose 47. The sampling device 40
delivers the
collected sample to the detection device 50 via a suction and/or a pumping
force. The
operator then reseals the mail item 17 and stores the mail item 17 in the
sealed
package cabinet 65 for storage during the remainder of the cycle. Another mail
item
17 can then be placed into the manual screening area 62 for manual processing.
[0037] Similarly, mail items 15 can be placed on the intake device 23 and
automaticalty fed into the access device 20. The access device 20 receives the
mail
items 15 one at a time, optionally creates openings 15a in each mail item 15,
and
feeds each mail item 15 into the pressurizing device 30. The pressurizing
device 30
compresses each mail item 15 so that a sample of the contents of the mail item
15 is
released through the openings 15a (or through pre-existing openings). The
sampling
device 40 collects and delivers the samples to the detection device 50 via a
suction
and/or a pumping force. When the mail items 15 exit the pressurizing device
30, the
mail items 15 are automatically deposited in the storage cart 27 for storage
during the
remainder of the cycle. Additionally, to reduce or prevent contamination of
the
environment external to the screening apparatus 10, the cycle steps discussed
above
can be performed under negative pressure maintained by the protective
enclosure 70.
[0038] A cycle of the screening apparatus 10 can screen a low to moderate
volume
of mail. For example, the screening apparatus 10 can be configured to process
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approximately 2,000 to 5,000 envelopes up to 1/4 inch thick in approximately
one
hour. The screening apparatus 10 can also include a user-friendly touch screen
interface 80 (shown in Figs. 1 and 2) with push button operation so that an
operator
can control the cycle. The screening apparatus 10 can be sized so that the
screening
apparatus 10 can be used on-site at various facilities, such as mail centers,
hospitals,
factories, commercial offices, and government offices. For example, the
screening
apparatus 10 can have a rectangular footprint of approximately 3 feet by 6
feet. The
screening apparatus 10 can also include rolling members, such as conventional
stem
or plat casters, for mobility.
[0039] Thus, according to embodiments of the present invention, a screening
apparatus 10 can provide accurate, rapid, safe, on-site testing for hazardous
agents
transmitted through mail items.
[0040] Modifications and other embodiments of the invention will be apparent
to
those skilled in the art from consideration of the specification and practice
of the
invention disclosed herein. It is intended that the specification and examples
be
considered as exemplary only, the scope of the invention being limited only by
the
appended claims.
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