The presem invention relates ?o a shielding apparatus for use sn conjunction with a sensing element, more specifically, but not exclusively, the invention resales to a 5 sensing element such as a laser sensor used for monitoring the presence of an article being processed Dy, for example, a packaging machine.

Laser sensors and other sensing elements can be used <n conjunction with processing machines such as packaging machines to monitor the qual-iy, integrity

^ and presence of articles as they are conveyed through s production or processing line Quality and safety controls are becoming evermore stringent and demands on production machines to increase output are always increasing, in such Circumstances, sensing elements are needed to monitor, amongst other aspects, the presence, type and quality of articles as they are conveyed and processed. In order

: > to monitor the quaiity and integnty of such articles the sensing elements need to he disposed in ciose proximity to the articles as they are processed, in certain processing environments this can be problematic due to the nature of the processing methods.

^■ o Electrical sensors can be sensitive to humidity and temperature and in some processing environments such sensors Will fail to operate due to the environmental conditions.

By providing an apparatus for shielding the sensing elements whsch does not restrict ?^ thesr performance as sensing elements, the present invention seeks to avoid or at least mitigate the above and other problems associated with the prior art

According to a first aspect of the present Invention there ss provided a shielding apparatus for use with a sensing element disposed withsn 3 processing apparatus, the sensing element for monstonng artscies processed by a radiating device

comprised within the processing apparatus, the shielding apparatus comprising a housing for shielding the sensing element, the housing composing a coupling means disposed to facilitate coupling between the sensing element and an article processed by the processing apparatus, and the housing being structured and arranged such > that radiation emitted by the radiating device and incident upon the sensing element is confined by the shielding apparatus.

Preferably wherein the sensing element comprises a radiation emitting element.

^; ■ ^■ > Optionally the housing comprises an upnght Uvular member wheresn the coupling means ineiudes an aperture disposed within the upnght tubular member, the aperture extends from a lower end of the upnght tubular member adjacent the sensing element, toward an upper end of said upnght tuβuiar member adjacent a path of articles being processed by the processing apparatus, such that coupling

;5 between the sensing element and said articles being processed effected

Optionally the sensing element is disposed in vertical registry wsth the coupling element to facilitate coupling between the sensing element and one of the articles, wherein the coupling element ss disposed in ørϊser relationship relative to the ^• o radiating device thereby to limit radiation emitted by the radiating device being directly incident upon the sensing element.

Preferably, the radiating device comprises an infra-red emitting lamp for heating a surface of an article being processed by the processing apparatus

Preferably me tubular member comprises one or more ventilation holes ro enable recycling of a;r within the housing thereby to reduce the heating effect on the housing caused by the Infra-red radiation emitted by the infra-red emitting lamp.

H? Optionally the housing further comprises a horizontal member, the upright member being mounted within lhe horizontal member such that the upnght tubular member and the horizontal member are in thermal oonraot, the horizontal member comonsino

a cooling system for reducing the heating effect on !he housing caused by radiation emitted by the infra-red emitting lamp. Preferably the cooling system is water based,

Ootionallv, the houssnq comprises a iaver of thermal insulaϋnq matenai for llmitino the heading effect on the housing caused Dy radiation emitted by the radiating device

Preferably the sensing element comprises a radiation emitting sensor tor monitoring the presence of artseies processed by the processing apparatus Even more preferably the radiation emitting sensor ss a iaser.

Optionally, riie sensing eiemem comprises a iaser-ernitting device, and the housing comprises an upnght tubular member extending from the sensing element toward the path of arucles processed by the processing apparatus, wheresn the coupling element may be provided by an optical fiber formed in part by a core of a first material and in part Dy a surrounding second maienai, the hrsr and second materials having refractive indices such that the radiation emitted hy the laser-envtting device is transmitted through the core to facilitate coupling between the sensing element and the articles

According to a second aspect of the present invention, there is provided a packaging machine for forming seated composite packages, the sealed composite packages formed by combining n?vo or more articles, the packaging machine comprises a radiating devica for processing, in part, one or each of the articles, a sensing element for monitoring one or each of the articles and a shielding apparatus according to the preceding paragraphs for restricting the incidence of radiation emitted by the radiating device upon the sensing element as the articles are processed and monϋored during me formation of a sealed composite package by the packaging machine.

An exemplary embodiment of the invention wiil now be described wsth reference to the accompanying drawings in which:

RGURE 1 shows a perspective view of a plurality of senssng elements and shielding apparatus according to one embodiment of the present invention. The entering apparatus are shown sn use within a heating station of a packaging machine, and

FIGURE 2 shows a cross -sectional view of one of the shielding apparatus shown m Figure 1.

i3 A shielding apparatus of the present invention will now be described m the context of an exemplary application, in which a seaied composite package ss formed by a packaging machine, in thrs application a packaging machine ss provided which seals an intermediary ariide, such as a busle? ^" pack of medicine or tablets wsthsr* an outer sleeve such as a paperboard carton blank, ft ss desirable, tor safety reasons, to

::» completely seal blister packs containing drugs Within psperboard sleeves so that the packages are child-proof.

Such packages may be produced Py pre-lreatsng a paperhoard sleeve with an adhesive which is reactivated by methods such as heating in one such process, an

:^ outer surface of a paperboard sleeve is condsuoned by cαniroiled heating as the paperboard sleeve ss conveyed though the machine toward a Plister pack feed mechanssm A blister pack is then placed onto the paperboard sleeve and adhered ^' thereto Py means of the heat reactivated adhesive. Due to the high-level of quahiy control associated with the packaging of pharmaceuticals and due io the safety

Hs measures necessary when utilising a heat source within a machine processing flammable material such as paperboard it *s important to monitor the progress.

condirjon and integrity of the processed articles throughout the packaging machine

U is particularly important to monitor lhe presence of paperboard blar ;ks when the :■ artsdes are conveyed through the heating station. The heat required to reactivate the adhesive generates a very high risk of fire, if a paperboard blank became jammed within the heating station it would sgnste wi?hιn seconds due to the flammable nature of the materiai and the intensity of heat.

so In the exemplary processing machine of the present embodiment, the heat conditioning process takes place within a heahπQ station 80 which is illustrated in Figure 1. The heat conditioning is achieved by means of medium wavelength Infrared emitting lamps 82 A plurality of radiating devices or heat lamps 82 may be provided as illustrated in Figure i . T he processed artsdes, m this case paperboard i > blanks 10 are conveyed along a track 70 sn the direction of ^λ >C as indicated As the blanks 10 are conveyed, infra-red radiation emitted from rhe lamps 82 is incident upon an outer surface of me blanks l ϋ and thereby heats the surface of the blanks 10 to reactivate the adhesive coated on the paperboard

hi To monitor the progress of the paperboard blanks 10 as they are conveyed a series of iocatson sensing elements are provided. A location sensing element 28 Is illustrated in cross-section m Figure 2 in this embodiment ihe location-sensing element 28 comprises a radiation emitting device OO such as a iaser-ernstting diode and a detector 62 such as a phorodiode. An optical ray 20 emitted by the me

:> emitting device 80 is disposed such tha* it intersects the path "X ^" of the conveyed articles 10. A series ol location sensing elements 28 are used such that throughout the heating station 80 the presence of an article 10 at each pitch of the packaging machine is monitored and checked. The presence of an article 10 is detected by She article interrupting the optical ray or laser beam 20 and reflecting the laser beam 20

^ toward the detector 62. A reflected or returned optical bean's 20 ss detected by the detector 62 and this indicates the presence of an article 10 A positive feedback signal is used to monitor the presence of articles 10 and the feedback signal ss

synchronised with the pitch and speed of the machine such thai if Hie laser beam is not interrupted when it ss expected to be, an alarm Signal can be raised to indicate the possibility that an article 10 has become jammed within the heating station, Additionally, the positive feedback Signal can be used to determine the possibility of two articies overlaying one another if for example lhe optical beam 20 is not interrupted when it is expected to be or is interrupted tor too iong if the overlaid blanks are staggered

The location sensing element 28 comprises a radiating emitting device, for example, a lighr emitting diode and a photodsode each o? when are eiectnoal devices which are sensitive to temperature and the environment of the conditioning section of the packaging machine in order to protect the sensing elements 28 from the heat radiation generated by the infra-red lamps a shielding apparatus is provided.

The shielding apparatus <!ø ss shown in Figure 1 and in c* ess -section in Figure 2 The shielding apparatus 40 comprises an upright tubular member 26 mounted within a horizontal member 30, The detector 62 of the sensing element 28 is disposed at a lower end of the upnght tubular member 26. Coniaiπed within the upright tubular member 26 is column of matenai 32 whsch may be a heal insulating material and/or light reflecting material A coupling means is provided by the pathway of the optical ray within the tubular member 26. The pathway extends from the iocauomsensmg element 28. through the core of the upright tubular member 26 and column of material 32 toward an aperture 38 in the upper end 34 of the upright tubular member 26, A typical pathway useful m the invention may be provided Py an optical frber . The pathway or coupling means facilitates coupling between the sensing element 28 and the articles 10 being processed by the packaging machine by allowing the optical ray or laser beam 20 to be transmitted through the upnght tubular member 26 The upper end 34 of the tubular member 26 comprises a pan of rhe coupling means, the part in this example being the aperture 36. The aperture 36 may sake the form of a circular hole, si zed only to allow a narrow optical beam to be transmitted therethrough, such that the remainder of the upper end 34 of the tubular member 26 reflects, and/or absorbs any radiation incident thereon to restrict or confine the

radiation emitted by the heating lamps 82 from penetrating ihe tubular member and affecting the operation of the sensing element 28, to prevent the register of incident radiation upon the sensing element fhus causing a fa^se Signal.

3 In Fig re 1 the upper end 34 of the tubular member 26 is illustrated, provided with a groove disposed in parallel alignment with ihe line of the heatmg lamps 82. This groove provides further deflectors of the infra-red radiation away from the coupling means, the aperture 36.

K; Due to Hie nature of the conditioning means of the packaging machine, the heating iarnps 82 are disposed above the path of the processed articles 10, the presence ano ¹ integrity of which is monitored by the sensing element 28 The sensing element 28 is disposed neneath the path of articles 10 and in order to reduce ihe magnitude and quantity of radiation being directiy incident upon rhe sensing elements the

;: ^; shielding elements are disposed such thai the coupling means 36 is positioned sn between two adjacent heating lamps 82, i.e. offset from the direct path of the conditioning radiators.

Within the heating station BO, an ssr circulation system is provided which extracts ::o warm a;r υ ^" from an upper portion of the hood and which inlets cooler asr ^" Z ^κ through a lower portion of the heating section 80, in this embodiment the upright tubular member 26 comprises a series of ventilation holes 24 which are provided Io facilitate the recycling of asr within ihe tubular member 26 Io facilitate a reduction of temperature within Ihe tubuiar member and/or to maintain a tower temperature within .:> the tubular member 26

The horizontal member 30 of the shielding apparatus, whilst not essential provides a support means for the upnght tubular member 26 and additionally may be provided with a water based cooling system, The upright tubular member 26 and horizontal ^: member 30 may be connected in thermal contact such that the water based cooling system comprised in the honzontai member 30 can assist In the cooling of the shielding apparatus 40 and thereby assist in maintaining the sensing element 28

withsπ a temperature range at which it can operate. A typical example c horizontal member 30 is a seaied, hollow rial structure made of metal, in which a flow passage for a coolant (e.g., water) is defined by guide panels.

> Upon reading the forgoing descriptors it will be apparent to one skilled in the art that various modifications could be made to the shielding apparatus heresπ described without departing form the scope of the present invention. For example, the shape and structure of the upright tubuiar member may take a different form to a tubular hollow structure, indeed if the heating lamps or other conditioning element are H: disposed in a different orientation relative to the articles to be processed then the shielding element may not comprise an upright tubular member, and/or the tubuiar member may have an alternative cross-sectional shape.

Preferably the upright tubular member 26 and the horizontal member 30 may be *; ^; made of a thermally conductive and/or reflective materia? such as aluminium or steel. Alternatively the horizontal member may not be provided or indeed may be used to support a number of upright tubular members,

Ii is also envisaged that In a processing rnachme employing means of conditioning ::o articles other than by heat or radiation, the shielding apparatus will be used to protect a sensing element from environmental conditions thai may affect the operation of the sensing element other than heat in such applications the coupling means may not take the form ef an aperture. For example it is envisaged that In other embodiments, the core of the upright tubuiar member 26 will comprise two ;;5 materials; an Inner core of a material having a first refractive index and a second outer cladding material having a second refractive index In this way the optical beam 20 would be transmuted within and confined to the inner core and the materials within lbs tubuiar member would further serve to protect the sensing element from a condition means such as humidifier.

Xi

In an alternative embodiment, the sensing element will not fake the form of a radiation emitter and detector, and/or ?he component parts of the sensing element

WiH be separately and oppositely disposed in this arrangement (he shielding apparatus itself may comprise two parts, each tor shielding a component pan of she seπssπg element

St is ai&o envisaged rhai the shielding apparatus of the present invention may find application m other processing machines a?xl Indeed ύ should r>ot be construed as any limitation on the scope of the invention that the shielding apparatus has been described sn the context of a specific packaging machine.