GB2391937A

GB2391937A - Mail screening unit for powders

Info

Publication number: GB2391937A
Application number: GB0219206A
Authority: GB
Inventors: Paul Anthony Kendall
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-08-17
Filing date: 2002-08-17
Publication date: 2004-02-18
Also published as: GB0219206D0

Abstract

A mail screening unit for items of mail containing hazardous powders (e.g. anthrax spores) has a containment case 6, a letter opening blade 3, and an envelope support guide 4. A method provides a process of punching a 5mm diameter hole 2, in an envelope 1, in one corner, the letter opening blade 3, is inserted inside the envelope 1, via the hole 2, the letter opening blade progressively widening such that at the base of the blade any powder contents secreted in the letter are released into the containment case. A beam, from a. light source unit 9, illuminates any fine powder particles failing into it, a magnifying lens 7 being provided, located in front of a CCTV camera 8 which captures images of any powder particles released. The video output of the camera can be displayed, recorded or further processed.

Description

This invention relates to a mail screening unit for powders method and apparatus.

The field of screening mail for powder content is new, however mail screening for explosive devices is well known and involves screening mail firstly for metal content, which indicates the possible presence of a power supply, the necessary detonator and any wiring. If metal is detected, the letter is then X-rayed, the discovery of metal content is what takes that one letter out of a bundle of two hundred letters and places it under close investigation and scrutiny using the X-ray equipment, the remaining 199 paper only letters (assuming they are correctly addressed, and assuming that they have no other outwardly suspicious characteristics) go on to final delivery inside the organisation in question.

The problem of hazardous powders, containing biological agents secreted in delivered mail passing straight through national postal system and existing mail screening operations was highlighted during attacks using anthrax spores in the autumn of 2001.

Screening mail for powders with the present invention, involves punching a 5mm diameter hole in the envelope of the letter being screened, the mail screening unit enables the restrictive opening of the letter releasing any powder secreted inside the letter into a containment chamber then detection and imaging apparatus enable the operator of the mail screening unit to determine one of two things :-

(a) the letter contains powder or (b) it does not contain powder.

The screening unit finds powder in mail only it can not identify the material, however as in screening for metal , if powder is found, that's enough to remove it from other letters and caH the police, because mail does not contain any powder particles and if they are found someone putthem there, small amounts or large, with or without a threatening note, are all suspicious.

If it turns out to be a hoax the police now have rapid testing kits and can rule them out quickly. According to the present invention there is provided a mail screening unit for powders method and apparatus comprising a containment case made of clear plastic in the form of a box with a single aperture slot cut into it's top panel, surrounding the aperture slot and rising up from and fixed to the case by the best means, an envelope guide and support made of moulded plastic and fashioned to enable a letter to be inserted into it, at an angle, so that one of comer of an envelope once fully inserted points down, to and over the aperture slot of the containment case, a letter opening blade fixed by the best means to the inside surface of the containment case, beneath and alongside the aperture slot, bending and curving up through the aperture through the middte space of the envelope guide and rising up to a point higher than the top of the envelope guide and cover material by at least 4 centimetres, this flat tapering stainless steel letter opening blade with two sharp or serrated edges is 3mm wide at it's uppermost tip widening progressively to at least 20mm wide at it's base where it then bends to the point where it is fixed to the case, a single sheet of black 3mm thickness smooth surface flexible foam rubber sheeting sized 21 cm x 29.6cm folded length ways and cut so that part of it can be slotted down the inside of the envelope guide until it reaches the base of the letter opening blade, the portion of the sheet protruding up above the top of the envelope guide is fold back over the top edges of the envelope guide and is then fixed permanently to the envelope guide and clipped along folded edges by the best means, the flexible cover sheeting providing a means of enabling an envelope to be inserted into the envelope guide in-between the springy side wall surfaces of the flexible sheeting which hug the sides of an inserted envelope preventing dust or fine powder particles drifting up from the powder release point at the base of the letter opening blade, to and into the environment above and surrounding the mail screening unit, a second case unit made of clear plastic provides a case housing for the containment case and it's restrictive mail opening attachments, the housing case also houses a visible light source unit of suitable brightness focused into a beam, the light source unit is located inside the housing case but outside the containment case and is positioned /placed by it's own weight or by magnetic force within the housing case, the light source unit located so that the beam of light emitted from the light source unit passes through a transparent wall of the containment case and traverses the inner space of the containment case across and through a plane directly beneath the aperture of the containment case to illuminate fine powder particles falling from a powder release point at the base of the letter opening blade which is an aforementioned feature of the containment case, also provided and located inside the housing case but outside of the containment case a CCTV camera 300 line picture resolution or more, the camera fitted with a wide angle fixed focus tens, a second larger magnifying lens is provided positioned in front of the CCTV camera, the camera and the magnifying lens pointing in a direction perendicular to the plane of the direction of aforementioned beam of light and capturing brightly illuminated and enlarged images of any fine particles floating in, or passing through the aforementioned beam, the CCTV camera's audio / video output conveyed via cable or microwave link to a suitable CCTV monitor screen located outside of the housing case, the audio video out put of the CCTV camera may also be fed into a video recorder or converted to a digital output and fed into a computer system for the images to be further analysed and processed , the CCTV camera with it's fixed focus lens is positioned / placed by it's own weight or magnetic force on a plastic chassis bed the chassis bed located and fixed by the best means to and at one end of the chassis bed is the large magnifying lens, the camera and tens chassis bed is positioned /placed by it's own weight or by magnetic force within the confines of the housing case, and outside of the containment case, provided is method, punching a hole in one comer of an envelope approximately 5mm in diameter, one centimetre from each of the two comer edges, made with a standard type single hole office paper punch, the hole in the envelope is then offered over the tetter opening blade, the blade then penetrates the inner part of the envelope and any papers within it, as the envelope is progressively lowered down the letter opening blade, the hole becomes wider and wider as the aforementioned blade widens the hole in the envelope, as the letter reached the furthest point which it can be inserted, any powder present will be released from the envelope falling into the aforementioned light beam, any fine particles illuminated in the beam are magnified by the tens and images captured by the CCTV camera, if powder is released it may be seen in two ways, firstly by the operator who looking through the clear plastic can see any powder present in the beam, the second way powder is detected is when images from the CCTV camera are enlarged and displayed on a provided CCTV monitor screen, if powder is discovered one of two provided spring G clamps is clamped around the envelope support and the envelope with in it, one or more G clamps will hold the letter in the jaws of the envelope support and prevent any powder aerosol escaping from the containment case, the containment case and it's mail opening attachments and the light unit may be used to screen mail without using the camera and monitor screen.

An embodiment of the invention will now be described by way of reference to the accompanying drawings in which :-

Figure 1 shows a cross section of the mail screening unit's containment case, the tetter support guide and it's flexible cover , illustrated are the relative locations of the light beam, CCTV camera and magnifying tens relative to each other, also shown the letter opening blade and a letter punched with a hole to be screened ;

Figure 2 shows how a letter is brought down the blade to open it and shows the light beams relative location to illuminate any powder particle fall from the envelope ;

Figure 3 shows the tetter opening blade's fixing point ;

Figure 4 shows the tetter support guide without the flexible cover sheet ;

Figure 5 shows the flexible envelope guide cover sheet and how it is cut and folded ;

Figure 6 shows the mail screening unit system housing case with the CCTV monitor screen ; Figure 7 shows a side view of the envelope support guide with the flexible cover sheet the sheet side clips the letter opening blade and a cross section of the containment case.

Referring to figure one, an envelope 1 , with a 5mm diameter hole 2, punched into one of it's comers, the hole 2, is made with a paper punch, the type that collects the part cut out in a compartment (the punch is not part of the invention). Punching a hole in the envelope in that location is part of the method provided, which is part of the invention.

Referring to figure one, the staiNess steel tetter opening blade 3, flat and 3mm wide at it's tip tapering to a width of at least 20mm at it's base, the blade bends to fix by riveting to the containment case 6, a six sided box the fifth sheet fixed by the best means, at final assembly in such a way, as it alone can be removed, the containment case 6, is made of transparent plastic acrylic or polycarbonate sheeting.

Referring to figure one, an aperture 10, is cut in the top sheet of the containment case 6, located over the aperture 10, and fixed to the containment case 6 , by 4 bolts and nuts, is the envelope support guide 4 , covering the envelope support guide 4 is the envelope support guide cover 5, which is made of flexible foam rubber sheeting, and fixed to the envelope support guide by the best means.

Referring to figure one, the magnifying lens and mount bed 7 , which can move left, right, backwards and forward and is located on the outside of the containment case 6 and fixed in place by it's own weight or magnetic force by attaching magnetic sheeting to the surfaces in question as needed, the cfiameter of the magnifying tens being at least 70mm. Referring to figure one, the CCTV camera is 8, fitted with a wide angle fixed focus lens, 300 line resolution or more with microwave or cable audio, video out put connection to a suitabte, CCTV monitor screen 11 , only shown in Figure six, the same audio, video out put of the CCTV camera can be connected into a suitable video recorder or converted and fed into a computer to be further processed or analysed.

Referring to figure one, the light source unit 9, produces a visible light source AC or DC of suitabte brightness, focused into a beam, to illuminate powder particles falling down into the inner part of the containment unit 3, the light source unit 9, is located on the outside of the containment unit 3, very small particles can be seen floating in the beam after powder has fallen through it, if very small amounts of powder are released they also will be lite up in the beam, tiie edges of particles glowing in the beam are thus enlarged.

Referring to figure two, the tetter opening blade 3 is shown inserted into the envelope 1 , the tetter opening blade 3, is penetrating inside the envelope, as the envelope is draw down the blade the hole will be enlarged as the blade widens, the tear can be enlarged further when the tetter is fully inserted, by tugging the envelopes sides, up and left or right against the sharpened or serrated edges of the flat letter opening blade 3.

Referring to figure three, the letter opening blade 3 is shown and how and where it is located it relation to the aperture opening in the top sheet of the containment unit 6.

Referring to figure four, the envelope support guide 4, is made of injection moulded plastic 1mm thickness, as per the shape shown in Fig 4, with holes in it's corners to enable it to be bolted to the containment case 6 (not shown in Fig 4). Referring to figure five, the envelope guide cover sheet 5, is made of flexible foam rubber or rubber sheet, the sheet must be of suitabte tiiickness, (at least 1 mm tNck- to 3mm tiiickness) the material being flexible but having a spring in it when folded, the envelope cover sheet 5, is folded and cut, from a single sheet of material as per the example shown in Fig 5.

Referring to figure six, a version of the invention is illustrated in Fig 6 , the CCTV monitor 11 is located out side of the housing case in a convenient position, the hosing case 12 is shown fashioned with a 50 mm wide ledge so that another case of exactly the same shape and size can be placed over, the housing case 12, and seal off further the containment case 3 tiiis containment measure is optional and is an addition to those of the restrictive tetter opening devices and the use of G clamps to close and lock the letter being screened in the jaws of the envelope support guide in cases where powder is found.

Referring to figure seven, The envelope support cover 5 and the envelope support 4 is shown in a side view, with the jaws of the envelope guide 4 opened out to illustrating the spring provided by the thin plastic walls of the envelope support guide 4, when in use the jaws are ideally closer together, however when an envelope is inserted they give slightly and being thin plastic spring back to close when the envelope is removed, further the envelope guide cover 5 provides further closure of the jaws of the device, two clips left 13, and right 14, are steel and fasten the the edges together of the flexible foam rubber sheeting , of 5, the envelope support guide cover, to seal and contain an envelope in the jaws of the envelope support guide 4, one or more spring loaded G clamps are attached to close the jaws trapping an envelope in-between them.

Claims

A mail screening unit for powders method apparatus comprising a containment case made of clear plastic in the form of a box with a single aperture slot cut into it's top panel, surrounding the aperture slot and rising up from and fixed to the case by the best means, an envelope guide and support made of moulded plastic and fashioned to enabte a tetter to be inserted into it, at an angle, so that one of comer of an envelope once fully inserted points down, to and over the aperture slot of the containment case, a tetter opening blade fixed by the best means to the inside surface of the containment case, beneath and alongside the aperture slot, bending and curving up through the aperture through the middle space of the envelope guide and rising up to a point higher than the top of the envelope guide and cover material by at least 4 centimetres, this flat tapering stainless steel letter opening blade with two sharp or serrated edges is 3mm wide at it's uppermost tip widening progressively to at least 20mm wide at it's base where it then bends to the point where it is fixed to the case, a single sheet of black 3mm thickness smooth surface flexible foam rubber sheeting sized 21 cm x 29*6cm folded length ways and cut so that part of it can be slotted down the inside of the envelope guide until it reaches the base of the tetter opening blade, the portion of the sheet protruding up above the top of the envelope gukte is fold back over the top edges of the envelope guide and is then fixed permanently to the envelope guide and clipped along folded edges by the best means, the flexible cover sheeting providing a means of enabling an envelope to be inserted into the envelope guide in-between the springy side wall surfaces of the flexibte sheeting wNch hug the sides of an inserted envelope preventing dust or fine powder particles drifting up from the powder release point at the base of the tetter opening blade, to and into the environment above and surrounding the mail screening unit, a second case unit made of clear plastic provides a case housing for the containment case and it's restrictive mail opening attachments, the housing case also houses a visible light source unit of suitable brightness focused into a beam, the light source unit is located inside the housing case but outside the containment case and is positioned /placed by it's own weight or by magnetic force within the housing case, the light source unit located so that the beam of light emitted from the light source unit passes through a transparent wall of the containment case and traverses the inner space of the containment case across and through a plane directly beneath the aperture of the containment case to illuminate fine powder particles falling from a powder release point at the base of the letter opening blade which is an aforementioned feature of the containment case, also provided and located inside the housing case but outside of the containment case a CCTV camera 300 line picture resolution or more, the camera fitted with a wide angle fixed focus lens, a second larger magnifying lens is provided positioned in front of the CCTV camera, the camera and the magnifying tens pointing in a direction perpendicular to the plane of the direction of aforementioned beam of light and capturing brightly illuminated and enlarged images of any fine particles floating in, or passing through the aforementioned beam, the CCTV camera's audio / video output conveyed via cable or microwave link to a suitabte CCTV monitor screen located outside of the housing case, the audio video out put of the CCTV camera may also be fed into a video recorder or converted to a digital output and fed into a computer system for the images to be further analysed and processed , the CCTV camera with it's fixed focus tens is positioned / placed by it's own weight or magnetic force on a plastic chassis bed the chassis bed located and fixed by the best means to and at one end of the chassis bed is the large magnifying tens, the camera and tens chassis bed is positioned /placed by it's own weight or by magnetic force within the confines of the housing case, and outside of the containment case, provided is method, punching a hole in one comer of an envelope approximately 5mm in diameter, one centimetre from each of the two comer edges, made with a standard type single hole office paper punch, the hole in the envelope is then offered over the tetter opening blade, the blade then penetrates the inner part of the envelope and any papers within it, as the envelope is progressively lowered down the letter opeNng blade, the hole becomes wider and wider as the aforementioned blade widens the hole in the envelope, as the tetter reached the furthest point which it can be inserted, any powder present will be released from the envelope falling into the aforementioned light beam, any fine particles illuminated in the beam are magnified by the tens and images captured by the CCTV camera, if powder is released it may be seen in two ways, firstly by the operator who looking through the clear plastic can see any powder present in the beam, the second way powder is detected is when images from the CCTV camera are enlarged and displayed on a provided CCTV monitor screen, if powder is discovered one of two provided spring G clamps is clamped around the envelope support and the envelope with in it, one or more G clamps will hold the tetter in the jaws of the envelope support and prevent any powder aerosol escaping from the containment case, the containment case and it's mail opeNng attachments and the light unit may be used to screen mail without using the camera and monitor screen.