GB2436448A

GB2436448A - Containment assembly comprising an operator booth with downward recirculatory airflow

Info

Publication number: GB2436448A
Application number: GB0705020A
Authority: GB
Inventors: Paul Hudson; Alan Wainwright
Original assignee: Extract Technology Ltd
Current assignee: Tetra Pak CPS Ltd
Priority date: 2006-03-17
Filing date: 2007-03-15
Publication date: 2007-09-26
Anticipated expiration: 2027-03-15
Also published as: GB2436448B; GB0705020D0; GB0605342D0

Abstract

A containment assembly comprises an operator booth 1 defining a box-like interior volume, capable of admitting an operator, and means for inducing a recirculatory airflow downwardly in the interior volume. The operator booth has an open front face 20 and a rear wall 7. The lower end of the rear wall receives the recirculatory airflow from the interior volume whilst the upper end of the rear wall transmits the recirculatory airflow. A ceiling plenum (60, fig.1b) defines a ceiling (61, fig.1b) and transmits the recirculatory airflow from the upper end of the rear wall through the ceiling downwardly into the interior volume. A baffle 10 shrouds a section of the ceiling and is adapted to divert a proportion of the recirculatory airflow 'A' from the ceiling plenum through the open front face. Preferably, the operator booth further comprises a perforated plate 103 in the path of the proportion of recirculatory airflow. The open front face of the operator booth is defined by first and second opposing side walls 2, where each side wall comprises a number of contiguous exterior and interior panels (24, 25; fig.3a) with the contiguous interior panels in opposed interlocking engagement with the contiguous exterior panels. A primary plenum 3a is provided together with one or more secondary plenums 3b, to the rear of the rear wall, downstream of the primary plenum. At least one fan unit (408, fig.5b) is situated to the rear of the rear wall, at or near to its upper end, with a unitary framework 4 adapted to mount the fan unit. A ceiling filter 5 has a sealant-filled perimeter channel, where the ceiling plenum includes a continuous knife edge (63, fig.6b) seated in the sealant-filled perimeter channel. One or more ceiling plenum-mounted lightboxes 6 are included for illuminating the interior volume. In use, the apparatus seeks to improve the performance of a down flow containment assembly by using a front air bleed to divert a proportion of clean air to the exterior of the operator booth.

Description

ASSEMBLY

The present invention relates to a containment assembly.

In conventional containment assemblies for use in (for example) handling pharmaceuticals, the air quality in the operator booth may be controlled using forced ventilation.

One category of forced ventilation is "down flow" in which surrounding air is drawn downwardly to entrain contaminants to a level below the handling area (eg to a level below the typical operators breathing zone) . For down flow containment, exhaust is usually carried out at low level relative to the source of the contaminant. :...:. *** * S * S. *

Current Good Manufacturing Practices exercised within the pharmaceutical manufacturing industry and legislation impose stringent demands on containment performance and operator *.: exposure levels of down flow containment assemblies. Features S...

of a conventional down flow containment assembly which *S * contribute to these factors include HEPA filters installed in *: the ceiling, PLF screen bleeds, partial width bleeds for generating turbulent air, sealant filled crevices, joints or ledges and pendant light fittings.

The present invention seeks to improve the performance of a down flow containment assembly by diverting a proportion of clean air to the exterior of the operator booth. In particular, the present invention relates to a down flow containment assembly comprising a judiciously positioned front bleed.

Thus viewed from one aspect the present invention provides a containment assembly comprising: an operator booth defining a box-like interior volume capable of admitting an operator, means for inducing a recirculatory airflow downwardly in the interior volume, wherein the operator booth has an open front face, a rear wall adapted at or near to its lower end to receive the recirculatory airflow from the interior volume arid at or near to its upper end to transmit the recirculatory airflow, a ceiling plenum defining a ceiling and capable of transmitting the recirculatory airflow from at or near to the upper end of the rear wall through the ceiling downwardly into the interior volume; and a baffle shrouding a section of the ceiling and adapted to divert a proportion of the recirculatory airflow from the ceiling plenum through the open front face.

By diverting a proportion of the downward airflow beyond the interior volume, the containment performance of the assembly is improved. The baffle is easy and rapid to install, *..

commission, dismantle (eg for cleaning) and maintain. The baffle is a viable alternative to providing a filter on the open front face of the assembly and may eliminate the need for separate bleed filters, expensive HEPA filters or PLF screen bleed arrangements.

Preferably the baffle is adapted to divert the proportion of the recirculatory airflow substantially horizontally.

In a preferred embodiment, the operator booth further comprises a perforated member (eq a perforated plate) in the path of the proportion of recirculatory airflow. The perforated member advantageously serves to diffuse the proportion of the recirculatory airflow. The perforated member is typically positioned at the open front face of the operator booth (eq at the upper end of the open front face) The perforated member may be substantially flush with the open front face of the operator booth. The perforated member is typically uniformly perforated.

Preferably the baffle substantially spans the open front face of the operator booth. This advantageously ensures that the proportion of recirculatory airflow is substantially uniform at and beyond the open front face.

Preferably the baffle is ceiling-mounted. Typically the baffle is ceiling-mounted to a close tolerance to prevent air jetting which might otherwise compromise the recirculatory airflow. * *

Preferably the baffle comprises a tapered wall positioned in the path of the proportion of recirculatory airflow to divert the proportion of the recirculatory airflow from the ceiling plenum through the open front face. The tapered wall may terminate in a horizontal base wall. Typically the tapered wall is tapered at about 45 to the vertical. ** * S. S.

The baffle may be composed of a wipe clean material such as steel.

Typically the containment assembly of the invention is adapted so that air falls in an undisturbed, non-turbulent manner past the region of the interior volume in which the operator operates ("the operator breathing zone") at a predetermined velocity. The assembly may be adapted to attain perfect laminar flow (PLF) of air. The ceiling plenum may comprise one or more ceiling plenum chambers. The or each ceiling plenum chamber may be generally adapted to minimise the ceiling plenum volume. The or each ceiling plenum chamber may be adapted to contribute to perfect laminar flow (PLF) To the or each ceiling plenum chamber may be mounted PLF material (eg a PLF screen) . To the or each ceiling plenum chamber may be mounted one or more HEPA filters.

The open front face of the operator booth may be defined by first and second opposing side walls joined in substantially parallel spaced apart relationship by the rear wall to support the ceiling plenum. One or more of the first side wall, second side wall and rear wall may be panelled.

In a preferred embodiment, each of the first side wall and the second side wall comprises: a plurality of contiguous exterior panels; and a plurality of contiguous interior panels, wherein the S....

contiguous interior panels are in opposed interlocking engagement with the contiguous exterior panels.

S S..

The contiguous exterior panels may be reversible. The contiguous interior panels provide a skin for the contiguous exterior panels. The skin advantageously minimises the number..

of joints, ledges or crevices exposed to the interior volume which need to be filled (eg by mastic) and hides exposed fasteners thereby eliminating areas of possible contamination. The contiguous exterior panels and contiguous interior panels provide easily wiped down surfaces inside and outside the booth. The embodiment is simply and rapidly constructed and installed.

The number of contiguous exterior panels will generally be determined by the size of the operator booth. The contiguous exterior panels may be mounted against a wall or equipment.

Each exterior panel may be self-standing. Each exterior panel is typically an upright U-shaped body. The upright U-shaped body may be symmetrically U-shaped. The upright U-shaped body may have a substantially planar outer wall. Extending from the lateral edges of the substantially planar outer wall may be respectively a first substantially orthogonal side wall and a second substantially orthogonal side wall. The first substantially orthogonal side wall may extend from the substantially planar outer wall by substantially the same degree as the second substantially orthogonal side wall.

Each interior panel may be self-standing. Each interior panel is typically an upright U-shaped body. The upright U-shaped body may be asymmetrically U-shaped. The upright U-shaped body may have a substantially planar outer wall. Extending from the lateral edges of the substantially planar outer wall may be respectively a first substantially orthogonal side wall and a second substantially orthogonal side wall.

Preferably the first substantially orthogonal side wall extends from the substantially planar outer wall to a greater degree than the second substantially orthogonal side wall.

In a preferred embodiment, the first substantially orthogonal *..

side wall of the exterior panel extends from the substantially planar outer wall by substantially the same degree as the second substantially orthogonal side and the first substantially orthogonal side wall of the interior panel extends from the substantially planar outer wall to a greater degree than the second substantially orthogonal side wall.

Preferably the plurality of contiguous interior panels and the plurality of contiguous exterior panels are offset to assist opposed interlocking engagement.

Preferably the plurality of contiguous interior panels and the plurality of contiguous exterior panels have substantially the same lateral dimension. The substantially planar outer wall of the interior panel and the substantially planar outer wall of the exterior panel may be of substantially equal width.

In a preferred embodiment, the inner face of the first substantially orthogonal side wall of a first exterior panel abuts the inner face of the second substantially orthogonal side wall of a first interior panel and the outer face of the second substantially orthogonal side wall of the first interior panel abuts the outer face of the first substantially orthogonal side wall of a second interior panel. Preferably the outer face of the second orthogonal side wall of the first exterior panel abuts the inner face of the second substantially orthogonal side wall of the second interior panel. This arrangement of opposed interlocking contiguous exterior and contiguous interior panels is repeatable over the plurality of interior panels and exterior..

panels so as to advantageously minimise the sealable space between panels. * *

Adjacent contiguous exterior panels and adjacent contiguous interior panels may be attached using a proprietary adhesive tape and adhesive liquid seal to eliminate any tendency for product entrapment whilst giving overall structural rigidity.

The exterior and interior panels may be adapted to provide exceptional noise damping and vibration isolation.

To the rear of the rear wall there may be one or more plenums adapted to transmit the recirculatory airflow from the lower end of the rear wall to the upper end of the rear wall.

In a preferred embodiment, the containment assembly further comprises: a primary plenum; and one or more secondary plenums to the rear of the rear wall downstream of the primary plenum, wherein the primary plenum has an at least partially open front face adjacent to or part of the rear wall at or near to its rear wall which is capable of transmitting airflow from the operator booth to the secondary plenum.

The primary plenum may be substantially full-width (eq substantially span the rear wall) . The or each secondary plenum may be less than full-width.

The (or each) secondary plenum may be rearwardly adjacent to the primary plenum. The (or each) secondary plenum may be fastened to the primary plenum by any conventional fastening member (eq bolts) . The (or each) secondary plenum may be an S* * .*S open-fronted, open-top compartment (eq a box-like compartment) of a width less than the width of the rear wall.

The open top of the secondary plenum may be located beneath (eq adjacent to) one or more filter housings. For example, the open top may be adapted to horizontally mount a filter housing such as a hepafilter housing. :: The primary plenum may be an open-fronted, elongate compartment (eq a box-like compartment) of a width substantially equal to the width of the rear wall. The open front is typically fitted with a perforated plate which may be detachable.

The (or each) secondary plenum may be in fluid cornrrtunication with the primary plenum. For this purpose, an exhaust aperture (eq a rearward exhaust aperture) in the primary plenum may be adjacent to the open front of the (or each) secondary plenum.

Preferably a basal wall of the primary plenum is inclined.

This usefully permits liquid or powder drainage.

Preferably a basal wall of the (or each) secondary plenum is inclined. This usefully permits liquid or powder drainage.

The primary plenum and/or the (or each) secondary plenum may be composed of a wipe clean material. The primary plenum and/or the (or each) secondary plenum may be modular. This reduces manufacturing costs and permits construction in situ.

The means for inducing the airflow may include one or more filters or a fan unit. For example, a fan unit may be housed in a fan housing to the rear of the rear wall (eq at or near to its upper end) * **.*.

In a preferred embodiment, the containment assembly further comprises to the rear of the rear wall at or near to its upper end: one or more fan units; and * * * I I a unitary framework adapted to mount and compartmentalise the one or more fan units. I... **S. *** * * I

By compartmentalising the (or each) fan unit in a framework, the containment assembly achieves low booth noise (eq less than about 72dba) and is lightweight to permit easier installation.

The unitary framework may be fitted with side diffusion plenums or isolation plates.

The unitary framework may be box-like (eg cuboidal or cubic) The unitary framework may be open-fronted. The unitary framework may be open-backed. The unitary framework may be open-top. The unitary framework may have one or more (eq a plurality) of open sides. The unitary framework may be fitted with a solid base. The solid base may include one or more inlet apertures.

In a preferred embodiment, the unitary framework is open top and open-sided and has a solid base with one or more inlet apertures. This advantageously permits airflow through the base, sides and top to drive the recirculatory airflow.

The unitary framework may mount and compartmentalise a plurality of fan units. For this purpose, the unitary framework may comprise a plurality of discrete compartments.

The plurality of compartments may be separated by an intervening diffusion plenum or isolation plate.

The unitary framework is preferably adapted to mount and compartmentalise twin fan units and the unitary framework S...

comprises discrete first and second compartments. S..

The unitary framework is preferably adapted to mount and compartmentalise a single fan unit and the unitary framework comprises a discrete first compartment. S.. * S*

A part (eg the top) of the unitary framework may comprise one or more (preferably twin) fan unit suspension members. The (or each) fan unit suspension member may comprise a cross-member (eg a cross-member spanning the open top of the unitary framework) Preferably the (or each) fan unit suspension member comprises twin cross-members spanning the open top of the unitary framework in substantially parallel spaced apart relationship.

The unitary framework typically comprises a plurality of struts (eq a plurality of horizontal struts and a plurality of vertical struts) . Each strut of the unitary framework may be fabricated from metal (eg aluminium or steel) extrusions which are joined in a conventional manner (eg permanently joined with an air tight corner piece) The fan unit may be driven by a motor. The fan unit may be seated on highly compressed anti-vibration mounts to ensure that no vibration is passed onto the adjacent parts of the operator booth.

The ceiling may be further defined by one or more ceiling filters mounted in or on the ceiling plenum. The ceiling plenum is typically equipped with a single or multiple ceiling filters. * *

In a preferred embodiment, the containment assembly further comprises: a ceiling filter with a sealant-filled perimeter channel, wherein the ceiling plenum includes a continuous knife edge seated in the sealant-filled perimeter channel. *.** * * ****

In a preferred embodiment, the knife edge is seated in the sealant-filled perimeter channel in a manner such that the interior volume of the booth is exposed to no sealant. This advantageously provides a clean interface for the working area of the operator booth.

The perimeter of the ceiling filter is typically pre-filled with sealant. The sealant may be a sealant gel. The ceiling filter may be a HEPA filter.

In a preferred embodiment, the containment assembly further comprises: one or more ceiling plenum-mounted lightboxes for illuminating the interior volume.

Preferably the one or more ceiling plenum-mounted lightboxes are recessed (eg upstream of the ceiling defined by the ceiling plenum and ceiling filter(s)). Particularly preferably the one or more ceiling plenum-mounted lightboxes are recessed to be substantially flush with the ceiling. In these embodiments (and for example in the absence of pendant light fittings), the downward airflow is exposed furthest downstream to a ceiling filter before entering the interior volume so that potential contaminants are removed.

The (or each) lightbox may be sealingly mounted in the ceiling plenum (eg in an air tight manner) * The (or each) lightbox may comprise a housing. The housing may be fastened to the ceiling plenum using conventional fasteners (eg with a gasket seal) . The lightbox may comprise a diffuser. *:.*. *.**

The rear wall of the operator booth may comprise a "service band" which may contain inter alia control buttons, the electrical and gauge piping and commissioning interface mounted on a fan unit.

In a preferred embodiment, the rear wall comprises: a rear wall framework; and a plurality of doors mounted in juxtaposition in the rear wall framework, wherein the plurality of doors are dismountable from the rear wall framework.

The plurality of dismountable doors permit ready access to equipment at the rear of the rear wall (eg filters and the fan unit) . This is particularly useful for safe change filtration.

The plurality of doors may be tool-free (eq quick release) dismountable or disrnountable by releasing fasteners (eg a plurality of bolts) . The plurality of doors are preferably a first door mounted in the rear wall framework in juxtaposition to a second door mounted in the rear wall framework, wherein the first door and the second door are tool-free disrnountable from the rear wall framework.

The number of doors is generally determined by the size of the operator booth and may be up to six.

Each door may be mounted in the rear wall framework by a plurality of pins engaging a plurality of bores. Preferably the pins (eg two pins) extend from the lower edge of the door and engage bushes (eg two bushes) in the rear wall framework (eg in the primary plenum) . The pins are typically remote from the end of the lower edge of the door. *:.*.

Preferably the rear wall comprises a plurality of releasable catches for restraining the plurality of doors in the rear The perimeter of each door may be sealingly engaged with a first face of a rear wall by a sealant (eg a silicone sealant) . Alternatively on the perimeter of each door may be mounted a seal (eg a resilient seal) . The seal may be sealingly engaged with a first face of the rear wall framework and a second face of the rear wall framework. For this purpose, the seal may comprise a furled portion mounted on the perimeter edge of the door which sealingly engages a first face of the rear wall framework, wherein the furled portion terminates in an unfurled portion which sealingly engages a second face of the rear wall framework.

The sealing arrangements dispense with the need for filling joints with chemical filler such as mastic which carry potential contaminants and need frequent replacement.

Viewed from a further aspect the present invention provides a containment assembly comprising: an operator booth defining a box-like interior volume capable of admitting an operator; means for inducing a recirculatory airflow downwardly in the interior volume, wherein the operator booth has an open front face, a rear wall adapted at or near to its lower end to receive the recirculatory airflow from the interior volume and at or near * to its upper end to transmit the recirculatory airflow, a ceiling plenum defining a ceiling and capable of transmitting.

the recirculatory airflow from at or near to the upper end of the rear wall through the ceiling downwardly into the interior volume, wherein the open front face of the operator booth is defined by first and second opposing side walls joined in substantially parallel spaced apart relationship by the rear wall to support the ceiling plenum, wherein each of the first side wall and the second side wall comprises: a plurality of contiguous exterior panels; and a plurality of contiguous interior panels, wherein the contiguous interior panels are in opposed interlocking engagement with the contiguous exterior panels.

Viewed from a yet further aspect the present invention provides a containment assembly comprising: an operator booth defining a box-like interior volume capable of admitting an operator; means for inducing a recirculatory airflow downwardly in the interior volume, wherein the operator booth has an open front face, a rear wall adapted at or near to its lower end to receive the recirculatory airflow from the interior volume and at or near to its upper end to transmit the recirculatory airflow, a ceiling plenum defining a ceiling and capable of transmitting the recirculatory airflow from at or near to the upper end of the rear wall through the ceiling downwardly into the interior volume; a primary plenum; and one or more secondary plenums to the rear of the rear wall downstream of the primary plenum, wherein the primary plenum has an at least partially open front face adjacent to or part of the rear wall at or near to its rear wall which is capable of transmitting airflow from the operator booth to the secondary plenum. :

I I..

Viewed from a yet still further aspect the present invention provides a containment assembly comprising: 1....: an operator booth defining a box-like interior volume..... I...

capable of admitting an operator; means for inducing a recirculatory airflow downwardly in the interior volume, wherein the operator booth has an open front face, a rear wall adapted at or near to its lower end to receive the recirculatory airflow from the interior volume and at or near to its upper end to transmit the recirculatory airflow, a ceiling plenum defining a ceiling and capable of transmitting the recirculatory airflow from at or near to the upper end of the rear wall through the ceiling downwardly into the interior volume; one or more fan units to the rear of the rear wall at or near to its upper end; and a unitary framework adapted to mount the one or more fan units.

Viewed from an even still further aspect the present invention provides a containment assembly comprising: an operator booth defining a box-like interior volume capable of admitting an operator; means for inducing a recirculatory airflow downwardly in the interior volume, wherein the operator booth has an open front face, a rear wall adapted at or near to its lower end to receive the recirculatory airflow from the interior volume and at or near to its upper end to transmit the recirculatory airflow, a ceiling plenum defining a ceiling and capable of transmitting the recirculatory airflow from at or near to the upper end of the rear wall through the ceiling downwardly into the, * interior volume; and a ceiling filter with a sealant-filled perimeter: channel, wherein the ceiling plenum includes a continuous knife edge seated in the sealant-filled perimeter channel. * . * ** **

Viewed from an even yet still further aspect the present * *** invention provides a containment assembly comprising: an operator booth defining a box-like interior volume capable of admitting an operator; means for inducing a recirculatory airflow downwardly in the interior volume, wherein the operator booth has an open front face, a rear wall adapted at or near to its lower end to receive the recirculatory airflow from the interior volume and at or near to its upper end to transmit the recirculatory airflow, a ceiling plenum defining a ceiling and capable of transmitting the recirculatory airflow from at or near to the upper end of the rear wall through the ceiling downwardly into the interior volume; and one or more ceiling plenum-mounted lightboxes for illuminating the interior volume.

The invention will now be described in a non-limitative sense with reference to the accompanying Figures in which: Figure la illustrates a side perspective view of a containment assembly in accordance with an embodiment of the invention; Figure lb illustrates a perspective view from below of the containment assembly in accordance with the embodiment of the invention; Figure ic illustrates a side elevation of the containment assembly in accordance with the embodiment of the invention; Figures 2a-c illustrate in isolation a front face of the containment assembly in accordance with the embodiment of the invention; Figures 3a-c illustrate in isolation a side wall of the containment assembly in accordance with the embodiment of the invention; Figures 4a and b illustrate in isolation rear plenums of the containment assembly in accordance with the embodiment of the.".

invention; Figure 5a illustrates in isolation a framework for a fan housing of the containment assembly in accordance with an embodiment of the invention; Figure 5b illustrates in isolation a framework for a fan housing of the containment assembly in accordance with an embodiment of the invention; Figures 6a and b illustrate in isolation a ceiling part of the containment assembly in accordance with the embodiment of the invention; Figures 7a and b illustrate in isolation a lightbox of the containment assembly in accordance with an embodiment of the invention; Figures 7c and d illustrate a lightbox of the containment assembly in accordance with an embodiment of the invention; Figures 8a and b illustrate in isolation the removable rear wall sections of the containment assembly in accordance with the embodiment of the invention.

With reference to Figures la-c, there is shown (in various views) an embodiment of the containment assembly of the invention. The containment assembly comprises generally an operator booth (1) defining an interior volume of a configuration and dimension sufficient to admit an operator.

The operator booth (1) has an open front face (20), a rear wall (7) and a ceiling plenum (60) defining a ceiling (61) In the operator booth (1), airflow is driven downwardly through the ceiling (61) and through the lower end of the rear wall (7)) . The airflow re-enters the interior volume from the rear of the rear wall (7) through the ceiling (61) . via the ceiling plenum (60) . More specific parts of the containment assembly will now be described with reference to Figure 1 and the remaining Figures. *0** * S...

Shown in more detail from the interior, the exterior (in * part) and in elevation in Figures 2a, b and c respectively, a baffle (10) substantially spans the open front face (20) of the operator booth (1) . The baffle (10) shrouds a section of the ceiling (61) to divert a proportion of the recirculatory airflow ((A) in Figure 2c) beyond the interior volume. The baffle (10) comprises a tapered wall (101) in the path of the proportion of recirculatory airflow (A) to divert the proportion of recirculatory airflow (A) through the open front face (20) -The tapered wall (101) terminates in a horizontal wall (102) which ensures that the proportion of recirculatory airflow (A) is diverted substantially horizontally to the exterior. The operator booth (1) further comprises a perforated plate (103) in the path of the proportion of recirculatory airflow (A) -The perforated plate (103) is positioned substantially flush with the open front face (20) of the operator booth (1) to ensure uniformed diffusion of the proportion of recirculatory airflow (A) The open front face (20) of the operator booth (1) is defined by first and second opposing side walls (2) which are shown in Figures 3a to 3c. Each of the side walls (2)comprises four contiguous exterior panels (24) and four contiguous interior panels (25) which face and interlock the contiguous exterior panels (24) . Each interior panel (25) is an upright U-shaped body (as shown in Figure 3c) comprising a substantially planar outer wall (25a) extending from the lateral edges of which are a first substantially orthogonal side wall (25b) and a second substantially orthogonal side wall (25c) . The first substantially orthogonal side wall (25b) is wider than the second substantially orthogonal side wall (25c) . Each exterior panel (24) is similar to the interior panel (25) illustrated in Figure 3c (and similar numerals will be adopted below) but first and second substantially orthogonal side walls (24b, 24c) are of equal width.

An opposing pair of the contiguous interior panels (25', 25) and an exterior panel (24) are shown in isolation in Figure 3b from which it will be apparent that the contiguous interior panels (25', 25) are offset from the contiguous exterior panels (24) to assist opposed interlocking engagement. The inner face of a first substantially orthogonal side wall (24b) of the exterior panel (24) abuts the inner face of a second substantially orthogonal side wall (25'c) of the first interior panel (25') and the outer face of the second substantially orthogonal side wall (25'c) of the first interior panel (25') abuts the outer face of a first substantially orthogonal side wall (25b) of the second interior panel (25) . The outer face of a second orthogonal side wall (24c) of the first exterior panel (24) abuts the inner face of a second substantially orthogonal side wall (25c) of the second interior panel (25) . This arrangement of opposed interlocking contiguous exterior and contiguous interior panels is repeatable over the four interior panels and exterior panels To the rear of the rear wall (7) is a secondary plenum (3b) downstream of a primary plenum (3a) (see Figures 4a and 4b) The primary plenum (3a) has an open front face (301) covered by a detachable perforated plate (37) which forms a part of the rear wall (7) . The primary plenum (3a) is substantially full width. The secondary plenum (3b) has an open-front (351) and an open top (352) and is of a width less than the width of the rear wall. The secondary plenum (3b) is rearwardly adjacent and fastened by bolts to the primary * : plenum (3a) and the open front face (301) is coincident with an exhaust aperture (302) in the primary plenum (3a) . The basal wall (303) of the primary plenum (3a) is inclined for drainage purposes. The basal wall (351) of the secondary plenum (3b) is also inclined for drainage purposes. Airflow *".: (A) is transmitted through the perforated plate (37) covering the open front face (301) of the primary plenum (3a), through the exhaust aperture (302), through the open front face (351) of the secondary plenum (3b) and through the open top (352) of the secondary plenum (352) . Mounted on the open top (352) is a filter housing (not shown) In an embodiment of the invention illustrated in Figure 5a, airflow (A) is induced by twin fan units (not shown in the Figures) mounted in a unitary framework (4). The unitary framework (4) comprises a plurality of horizontal struts (47) and vertical struts (49) in a box like configuration and compartmentalises the twin fan units in discrete compartments (41 and 42) separated by an intervening diffusion plenum (400) . The unitary framework (4) is fitted with side diffusion plenums (43 and 44) . The unitary framework (4) is (at least in part) open top and open sided and has a solid base with twin inlet apertures (45 and 46) The twin fan units are mounted respectively on the inlet apertures (45 and 46) so that airflow (A) is transmitted through the inlet apertures (45 and 46), the sides and the top of the unitary framework (4) to drive recirculatory airflow. Each of the twin tan units is suspended on twin cross members (48) spanning the open top of the unitary framework (4) In an embodiment of the invention illustrated in Figure 5b, airflow is induced by a single fan unit (408) mounted in a S **.S S unitary framework (4) . The unitary framework (4) comprises a plurality of horizontal struts (47) and vertical struts (49) in a box like configuration and compartmentalises the fan unit (408) in a discrete compartment (41) . The unitary framework (4) is (at least in part) open top and open sided and has a solid base with an inlet aperture (45) . The fan S...

unit (408) is mounted on the inlet aperture (45) so that airflow is transmitted through the inlet aperture (45), the sides and the top of the unitary framework (4) to drive recirculatory airflow. The fan unit (408) is suspended on twin cross members (48) spanning the open top of the unitary framework (4) The ceiling (61) is further defined by a ceiling filter (5) (see Figures 6a and 6b) mounted in the ceiling plenum (60) The ceiling filter (5) is equipped with a sealant-filled perimeter channel in which is seated a continuous knife-edge (63) on the sealing plenum (60) . This creates a sealing mounting between the ceiling filter (5) and ceiling plenum (60) without exposing the interior volume of the operator booth (1) to sealant.

The operator booth (1) is illuminated in a first embodiment by a light box (6) which is recess mounted in the ceiling plenum (60) (see Figures 7a and 7b) . The light box (6) is substantially flush with the ceiling (61) and is mounted in a sealing manner. The light box (6) comprises a housing (67) for bulbs (68) which is fastened to the plenum (60) by fasteners and gasket seals (69). The housing (67) is fitted with a diffuser (70) The operator booth (1) is illuminated in a second embodiment by a light box (600) which is recess mounted in a recess (62) of the ceiling plenum (6000) (see Figures 7c and d) For the sake of clarity, Figure 7d shows only one of the two ****S filters (680) which are illustrated in Figure 7c. The light S..,.

box (600) comprises a housing (675) for bulbs. The housing (67) is fitted with a diffuser (676) . The light box (600) is substantially flush with the ceiling (610) . The periphery (650) of the the light box (600) is provided with spaced apart apertures (660) which engage complimentary spaced *..

apart studs (640) around the circumference of the recess (62) in the plenum (6000) to enable the light box (600) to be seated in the ceiling plenum (6000) As illustrated in Figure lb, the rear wall (7) is provided with a service band (7a) which contains control buttons and commissioning interfaces operable from the interior volume of the operator booth (1) by the operator. As shown in Figures 8a and 8b, the rear wall (7) comprises a rear wall framework (73), a first door (74) mounted in the rear wall framework (73) in juxtaposition to a second door (75) mounted in the rear wall frame like (73) . The first door (74) and the second door (75) are dismountable from the rear wall framework (73) without tooling. This permits ready access to equipment at the rear of the rear wall (7) . The rear wall framework (73) is provided in part by the service band (7a) and the primary plenum (3a) . The first door (74) and second door (75) are mounted in the rear wall framework by pins (97) in their lower edge engaging bushes (98) in the upper edge of the primary plenum (3a) The first door (74) and second door (75) are restrained by releasable catches (99) * * S. * . . *5 S

S S..

S * * * * S S. 55 S.' * . S... *. * *I

Claims

CLAIMS

1. A containment assembly comprising: an operator booth defining a box-like interior volume capable of admitting an operator, means for inducing a recirculatory airflow downwardly in the interior volume, wherein the operator booth has an open front face, a rear wall adapted at or near to its lower end to receive the recirculatory airflow from the interior volume and at or near to its upper end to transmit the recirculatory airflow, a ceiling plenum defining a ceiling and capable of transmitting the recirculatory airflow from at or near to the upper end of the rear wall through the ceiling downwardly into the interior volume; and S... * . S

a baffle shrouding a section of the ceiling and adapted to divert a proportion of the recirculatory airflow from the ceiling plenum through the open front face. * * : *. S.
2. A containment assembly as claimed in claim 1 wherein..

the baffle is adapted to divert the proportion of the *,: recirculatory airflow substantially horizontally.

3. A containment assembly as claimed in claim 1 or 2, wherein the operator booth further comprises a perforated member in the path of the proportion of recirculatory airflow.

4. A containment assembly as claimed in claim 1, 2 or 3 wherein the baffle substantially spans the open front face of the operator booth.

5. A containment assembly as claimed in any preceding claim wherein the baffle is ceiling-mounted.

6. A containment assembly as claimed in any preceding claim wherein the baffle comprises a tapered wall positioned in the path of the proportion of recirculatory airflow to divert the proportion of the recirculatory airflow from the ceiling plenum through the open front face.

7. A containment assembly as claimed in any preceding claim adapted so that air falls in an undisturbed, non-turbulent manner past the region of the interior volume in which the operator operates at a predetermined velocity.

8. A containment assembly as claimed in any preceding claim wherein the open front face of the operator booth is defined by first and second opposing side walls joined in * substantially parallel spaced apart relationship by the rear wall to support the ceiling plenum, wherein each of the first side wall and the second side wall comprises: :.

a plurality of contiguous exterior panels; and a plurality of contiguous interior panels, wherein the contiguous interior panels are in opposed interlocking **1* engagement with the contiguous exterior panels.

9. A containment assembly as claimed in claim 8 wherein the contiguous interior panels provide a skin for the contiguous exterior panels.

10. A containment assembly as claimed in claim 8 or 9 wherein each exterior panel is self-standing.

11. A containment assembly as claimed in claim 8, 9 or 10 wherein each interior panel is self-standing.

12. A containment assembly as claimed in any of claims 8 to 11 wherein the exterior panel has a substantially planar outer wall, wherein extending from the lateral edges of the substantially planar outer wall is respectively a first substantially orthogonal side wall and a second substantially orthogonal side wall, wherein the first substantially orthogonal side wall extends from the substantially planar outer wall by substantially the same degree as the second substantially orthogonal side wall, and wherein the interior wall has a substantially planar outer wall, wherein extending from the lateral edges of the substantially planar outer wall is respectively a first substantially orthogonal side wall and a second substantially orthogonal side wall, wherein the first substantially orthogonal side wall extends from the substantially planar outer wall to a greater degree than the second substantially orthogonal side wall. I... * * *

13. A containment assembly as claimed in any of claims 8 to 12 wherein the plurality of contiguous interior panels and the plurality of contiguous exterior panels are offset to assist opposed interlocking engagement. **** * S S...

14. A containment assembly as claimed in any of claims 8 to ***: 13 wherein the plurality of contiguous interior panels and the plurality of contiguous exterior panels have substantially the same lateral dimension.

15. A containment assembly as claimed in any of claims 8 to 14 wherein the inner face of the first substantially orthogonal side wall of a first exterior panel abuts the inner face of the second substantially orthogonal side wall of a first interior panel and the outer face of the second substantially orthogonal side wall of the first interior panel abuts the outer face of the first substantially orthogonal side wall of a second interior panel.

16. A containment assembly as claimed in claim 15 wherein the outer face of the second orthogonal side wall of the first exterior panel abuts the inner face of the second substantially orthogonal side wall of the second interior panel.

17. A containment assembly as claimed in any preceding claim further comprising: a primary plenum; and one or more secondary plenums to the rear of the rear wall downstream of the primary plenum, wherein the primary plenum has an at least partially open front face adjacent to or part of the rear wall at or near to its rear wall which is capable of transmitting airflow from * * the operator booth to the secondary plenum. * * S I. S

18. A containment assembly as claimed in any preceding claim further comprising to the rear of the rear wall at or near to its upper end: one or more fan units; and S...

a unitary framework adapted to mount and ***.: compartmentalise the one or more fan units.

19. A containment assembly as claimed in claim 18 wherein the unitary framework is open top and open-sided and has a solid base with one or more inlet apertures.

20. A containment assembly as claimed in claim 18 or 19 wherein the unitary framework is adapted to mount and compartmentalise twin fan units and the unitary framework comprises discrete first and second compartments.

21. A containment assembly as claimed in any preceding claim wherein the ceiling is further defined by one or more ceiling filters mounted in or on the ceiling plenum, wherein the containment assembly further comprises: a ceiling filter with a sealant-filled perimeter channel, wherein the ceiling plenum includes a continuous knife edge seated in the sealant-filled perimeter channel.

22. A containment assembly as claimed in claim 21 wherein the knife edge is seated in the sealant-filled perimeter channel in a manner such that the interior volume of the booth is exposed to no sealant.

23. A containment assembly as claimed in any preceding claim further comprising: one or more ceiling plenum-mounted lightboxes for * * ****** illuminating the interior volume. * I I I. I

24. A containment assembly as claimed in claim 23 wherein * *1I the one or more ceiling plenum-mounted lightboxes are. * recessed to be substantially flush with the ceiling. ,11 I... * S

25. A containment assembly as claimed in any preceding **,: claim wherein the rear wall comprises: a rear wall framework; and a plurality of doors mounted in juxtaposition in the rear wall framework, wherein the plurality of doors are dismountable from the rear wall framework.

26. A containment assembly comprising: an operator booth defining a box-like interior volume capable of admitting an operator; means for inducing a recirculatory airflow downwardly in the interior volume, wherein the operator booth has an open front face, a rear wall adapted at or near to its lower end to receive the recirculatory airflow from the interior volume and at or near to its upper end to transmit the recirculatory airflow, a ceiling plenum defining a ceiling and capable of transmitting the recirculatory airflow from at or near to the upper end of the rear wall through the ceiling downwardly into the interior volume, wherein the open front face of the operator booth is defined by first and second opposing side walls joined in substantially parallel spaced apart relationship by the rear wall to support the ceiling plenum, wherein each of the first side wall and the second side wall comprises: a plurality of contiguous exterior panels; and a plurality of contiguous interior panels, wherein the contiguous interior panels are in opposed interlocking engagement with the contiguous exterior panels.

27. A containment assembly comprising: .. : an operator booth defining a box-Jike interior volume capable of admitting an operator; * ** ** means for inducing a recirculatory airflow downwardly in the interior volume, **** wherein the operator booth has an open front face, a rear wall adapted at or near to its lower end to receive the recirculatory airflow from the interior volume and at or near to its upper end to transmit the recirculatory airflow, a ceiling plenum defining a ceiling and capable of transmitting the recirculatory airflow from at or near to the upper end of the rear wall through the ceiling downwardly into the interior volume; a primary plenum; and one or more secondary plenums to the rear of the rear wall downstream of the primary plenum, wherein the primary plenum has an at least partially open front face adjacent to or part of the rear wall at or near to its rear wall which is capable of transmitting airflow from the operator booth to the secondary plenum.

28. A containment assembly comprising: an operator booth defining a box-like interior volume capable of admitting an operator; means for inducing a recirculatory airflow downwardly in the interior volume, wherein the operator booth has an open front face, a rear wall adapted at or near to its lower end to receive the recirculatory airflow from the interior volume and at or near to its upper end to transmit the recirculatory airflow, a ceiling plenum defining a ceiling and capable of transmitting the recirculatory airflow from at or near to the upper end of the rear wall through the ceiling downwardly into the interior volume; one or more fan units to the rear of the rear wall at or near to its upper end; and a unitary framework adapted to mount the one or more fan units. *... :

29. A containment assembly comprising: an operator booth defining a box-like interior volume capable of admitting an operator; means for inducing a recirculatory airflow downwardly ** in the interior volume, wherein the operator booth has an open front face, a rear wall adapted at or near to its lower end to receive the recirculatory airflow from the interior volume and at or near to its upper end to transmit the recirculatory airflow, a ceiling plenum defining a ceiling and capable of transmitting the recirculatory airflow from at or near to the upper end of the rear wall through the ceiling downwardly into the interior volume; and a ceiling filter with a sealant-filled perimeter channel, wherein the ceiling plenum includes a continuous knife edge seated in the sealant-filled perimeter channel.

30. A containment assembly comprising: an operator booth defining a box-like interior volume capable of admitting an operator; means for inducing a recirculatory airflow downwardly in the interior volume, wherein the operator booth has an open front face, a rear wall adapted at or near to its lower end to receive the recirculatory airflow from the interior volume and at or near to its upper end to transmit the recirculatory airflow, a ceiling plenum defining a ceiling and capable of transmitting the recirculatory airflow from at or near to the upper end of the rear wall through the ceiling downwardly into the interior volume; and one or more ceiling plenum-mounted lightboxes for illuminating the interior volume. * S

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