THE PRESENT INVENTION relates broadly to the area of
heating, ventilating and air conditioning systems and more
particularly to an apparatus for directing and regulating
the flow of air from an outlet of the heating, ventilating
or air conditioning system into a room space.
At an outlet of a heating, ventilating or air
conditioning system air will typically pass from ducting
along which it has been conveyed through a plenum chamber,
which may be regarded as a box which acts as an air buffer,
through some form of damping arrangement which serves to
regulate the flow of air through the outlet and a grille or
diffuser which serves to direct the flow of air so that it
moves in a desired direction as it enters the space to be
ventilated. It is the grille or diffuser which is visible
within the room which is being ventilated.
The present invention is particularly concerned
with apparatus for directing and regulating the flow of air
at an outlet which incorporates a diffuser and is
particularly suited for use with an arrangement mounted in
a floor. Circular floor outlets are being used in
increasing numbers for underfloor supply and displacement
based systems. The floor diffusers are mounted within an
aperture in a floor tile so as to be substantially flush
with the floor surface.
Such floor diffusers need to be adjustable so as to
provide variable flow rates and variable air discharge
patterns. This is because it is relatively common for
larger working spaces to be sub-divided and re-arranged at
various times thereby necessitating the adaption of the
room ventilation system to suit the particular room design
and positioning of employees etc. It is known to provide
an adjustable floor diffuser of this type and one design of
such a diffuser is disclosed in EP-A-0446557. Whilst the
diffuser shown in that specification provides for
adjustable air discharge patterns and flow rates, the
adjustment of the air discharge pattern requires the
careful adjustment of two plates which make up the diffuser
relative to one another and the fixing of the two plates in
position. The adjustment of the air discharge pattern is
therefore not a totally straightforward task. Whilst it is
desirable to be able quickly and simply to dismantle the
diffuser and adjust the air discharge pattern, it is not
desirable that the diffuser should be readily removable
from its flush-mounted position within the floor by hand.
A problem which has been encountered with existing
designs of floor diffusers is that the damper is
constituted by aligned apertures provided in a dirt tray
and a mounting frame, with the aligned apertures being
adjustable relative to each other to vary the degree of
damping (i.e. the air flow rate). In previous designs
whilst the appropriate degree of air damping could be set
upon installation of the apparatus it has been found that
when the dirt tray is removed for cleaning or maintenance
purposes it is commonly replaced in the incorrect position
so that the degree of air damping is no longer as desired.
In addition, the assembly and dismantling of prior art
apparatus of this type has not been entirely
straightforward, thereby necessitating the attendance of
skilled personnel to effect cleaning and maintenance tasks.
The present invention seeks to provide an improved
apparatus for directing and regulating the flow of air from
an outlet of a heating, ventilating or air conditioning
system.
One aspect of this invention provides a diffuser
for use adjacent an outlet of a heating, ventilating or air
conditioning system, the diffuser comprising a plate-like
element having a pair of opposed, exposed surfaces, the
plate-like element defining apertures to permit a flow of
air therethrough and having means for releasably fixing the
element in an opening constituting the outlet of the
heating, ventilating or air conditioning system, each
aperture through the diffuser meeting the opposed, exposed
surfaces at differing angles to the two surfaces, the
releasable fixing means permitting fixing of the diffuser
within said opening in two alternative orientations, the
arrangement being such that in a first orientation air is
diffused through one of the opposed, exposed surfaces in a
first direction and in an inverted orientation air is
diffused through the other of the opposed, exposed surfaces
in a second, different direction.
Preferably each aperture through the diffuser
element has first and second portions, the first portion of
the aperture meeting its associated exposed surface at an
angle of less than 60 degrees to that surface so as to
provide a generally horizontal air discharge pattern when
in use with air discharging from the diffuser through that
first portion of the aperture and the second portion of the
aperture meeting its associated exposed surface at an angle
greater than 60 degrees to that surface so as to provide a
generally vertical air discharge pattern when in use with
air being discharged from the diffuser through that second
portion of the aperture.
Conveniently each aperture has a portion meeting
one exposed surface at an angle of approximately 50 degrees
to the horizontal and a portion meeting the other exposed
surface at an angle of approximately 71 degrees to the
horizontal.
Advantageously each aperture has a portion which
converges in the direction in which air flows through the
aperture when air discharges from the diffuser through that
portion of the aperture.
Preferably the plate-like diffuser element is
formed as two halves which are permanently interconnected,
the two halves comprising a top plate and a bottom plate,
each half defining one of the opposed, exposed surfaces,
the first and second portions of each aperture being formed
in respective halves of the diffuser element.
At the junction between the two halves of the
diffuser element, each aperture through the diffuser may
define a step or discontinuity for creating turbulence in
a flow of air through the aperture.
The diffuser may be provided in combination with a
mounting frame, the mounting frame defining the opening
constituting the outlet of the heating, ventilating or air
conditioning system, the releasable fixing means comprising
a snap-fitting arrangement permitting the releasable fixing
of the diffuser within the mounting frame in either of said
two alternative orientations.
Conveniently when mounted in the frame, the
outwardly direct, exposed surface of the diffuser lies
substantially flush with the frame and with minimum
clearance between the diffuser and the frame to prevent
removal of the diffuser from the frame other than by using
a tool designed for the removal of the diffuser.
A second aspect of this invention provides a
mounting arrangement for mounting a diffuser adjacent an
outlet of a heating, ventilating or air conditioning
system, the arrangement comprising a diffuser in the form
of a plate-like element defining apertures to permit a flow
of air therethrough and a mounting frame locatable adjacent
the outlet of the heating, ventilating or air conditioning
system, the mounting frame defining an opening for
receiving the diffuser with minimal clearance between the
diffuser and the frame, the diffuser and the frame being
formed with co-operating means for releasably retaining the
diffuser in position with the aperture within the mounting
frame to prevent undesired removal of the diffuser by hand
without the use of a tool for releasing the retaining
means.
Preferably the diffuser has an outwardly directed,
exposed surface which lies substantially flush with the
outwardly directed surface of the mounting frame when the
diffuser is received within the mounting frame, the
arrangement being such that no part of the diffuser upon
which purchase can be gained is exposed.
Conveniently the diffuser defines an internal,
undercut recess to which access is gained via an aperture
in the diffuser, a hook-like tool being provided, part of
the tool being adapted to engage said undercut recess to
enable the diffuser to be removed from the opening defined
by the frame.
A third aspect of this invention provides an
apparatus for directing and regulating a flow of air from
an outlet of a heating, ventilating or air conditioning
system, the apparatus comprising a first component defining
a plurality of apertures to permit a through flow of air,
a second component defining a plurality of apertures of
similar size to the apertures in the first component and
also to permit a through flow of air, the first and second
components being mounted adjacent each other and being
movable relative to each other such that the apertures can
be moved between positions of differing degrees of
alignment to regulate a flow of air through the two
components, means being provided for releasably fixing the
first and second components relative to each other to give
a desired degree of alignment between the apertures in the
first and second components and thereby give a desired air
flow rate, said releasable fixing means permitting removal
of one component from its position adjacent the other
component for maintenance or the like purposes, the fixing
means being such that the removed component can only be
replaced in the same position relative to the other
component as that from which it was removed thereby
ensuring that the desired air flow rate setting is
maintained.
Preferably the releasable fixing means comprise a
peg mountable at one of a plurality of positions on the
first component, the locations corresponding to different
degrees of alignment between the apertures in the first and
second components and an opening in part of the second
component, the arrangement being such that when the peg is
mounted at one of said locations on the first component
part of the peg projects upwardly such that the second
component can only be mounted adjacent the first component
in one predetermined position in which the projecting part
of the peg extends into the opening formed in the second
component.
Conveniently the plurality of locations defined by
the first component comprise a plurality of dovetail
sectioned slots and the peg comprises a dovetail-sectioned
peg designed to be received in the slots, the peg having a
head which projects beyond the end of the slot to form the
projecting portion which is received within the opening in
the second component.
Advantageously the plurality of locations at which
the peg may be mounted on the first component are off-set
from one another by a differing amount to that by which the
apertures in the first and second components are off-set
from one another such that the repositioning of the peg
from one location to the next provides a change in the
degree of alignment of the apertures in the first and
second components.
A fourth aspect of this invention provides an
apparatus for directing a flow of air from an outlet of a
heating, ventilating or air conditioning system, the
apparatus comprising a plenum chamber and one or more
further components disposed between the plenum chamber and
the outlet, the plenum chamber having an inlet adapted to
be connected to ducting of the heating, ventilating or air
conditioning system so as to receive air supplied via the
ducting, the plenum chamber also having an outlet through
which air flows from the chamber to a further component
forming part of the apparatus, the plenum chamber and the
further component having co-operating means forming a
substantially airtight snap fitting connection between the
outlet of the plenum chamber and the further component.
Preferably the means forming the substantially
airtight snap fitting connection between the outlet of the
plenum chamber and the further component comprise a co-operating
resilient lip and a step or recess formed on the
plenum chamber and the further component, movement of the
plenum chamber and the further component into engagement
with each other serving automatically to cause the lip to
become captively engaged behind the step or recess thereby
connecting the outlet of the plenum chamber to the further
component.
Conveniently the lip is formed around the periphery
of the plenum chamber outlet and the step is defined by the
further component to which the plenum chamber is to be
connected.
Advantageously the plenum chamber has a
substantially circular outlet and the step or recess is
defined in an outwardly directed surface of a
corresponding, annular part of the further component, the
annular part of the further component widening in the
direction in which the plenum chamber is moved into
engagement therewith such that the resilient lip flexes
outwardly as the plenum chamber and the further component
are moved together prior to snap-fitting into the step or
recess.
In order that the present invention may be more
readily understood and so that further features thereof may
be appreciated the invention will now be described by way
of example with reference to the accompanying drawings in
which:
FIGURE 1 is an exploded cross-sectional view of an
apparatus for directing and regulating the flow of air from
an outlet of a heating, ventilating or air conditioning
system; FIGURE 2 shows the apparatus of Figure 1 when in an
assembled condition; FIGURE 3 is a schematic perspective view of a
diffuser forming one aspect of the present invention; FIGURE 4 is a partial cross-sectional view taken on
the line IV-IV in Figure 3, illustrating features adjacent
the periphery of the diffuser; FIGURE 5 is a rough plan view of that part of the
apparatus illustrated in the right hand portion of Figure
4; FIGURE 6 is a cross-sectional view taken on the
line VI-VI in Figure 3; FIGURE 7 is a view corresponding to Figure 6 but
showing the diffuser in an inverted orientation; and FIGURES 8 and 9 are cross-sectional views through
part of an alternative arrangement used for mounting the
apparatus in a concrete slab floor.
Referring initially to Figure 1 of the drawings
there is shown an apparatus for directing and regulating
the flow of air from an outlet of a heating, ventilating or
air conditioning system where the apparatus is designed to
be mounted in a floor. A floor tile is illustrated
schematically as reference numeral 1 and defines a circular
aperture 2 designed to receive the apparatus. The
apparatus generally comprises a mounting frame 3, part of
which is threaded and which carries a threaded mounting
collar 4. The mounting frame 3 is passed into the hole 2
in the floor tile 1 from above whilst the mounting collar
4 is screwed onto the threaded part of the mounting frame
from beneath and may thereby be moved up such that the
floor tile is sandwiched between an upper part of the
mounting frame 3 and the mounting collar 4.
A damper/dirt tray 5 is received within the
mounting frame 3 and a diffuser disc 6 sits on top of the
uppermost rim of the damper/dirt tray 5 and extends across
the opening defined at the top of the mounting frame 3. A
plenum box 7 is mounted on the outer edge of the mounting
collar 4 and is positioned beneath the floor tile and has
means for connection to ducting or the like by way of which
air is conveyed to the outlet where the apparatus is
installed. The complete apparatus is centrally located
with respect to the central axis 8 of the aperture 2 and is
of generally "circular" form in plan view.
Looking at the individual components of the
apparatus in more detail, the mounting frame 3 is generally
circular in plan view and has an upper portion bounded by
an upstanding wall 9 which is formed, at its upper end,
with an outwardly directed lip or flange 10. The upper
portion is designed to accommodate the diffuser disc 6.
The wall 9 extends, at its lower end, inwardly such that a
step 11 is defined at a junction between the upper wall 9
and a central wall 12 which is formed with an external
thread 13. At its lower end the central wall 12 leads into
a lower portion of the mounting frame which comprises a
wall 14 which extends downwardly and inwardly and which
defines eight generally rectangular air inlet apertures 15
which are equally spaced, in a circumferential direction,
around the wall 14.
The upper portion of the mounting frame 3 is so
designed that it will pass through the aperture 2 formed in
the floor tile 1 with the wall 9 accommodated within the
aperture and the lip or flange 10 seated upon the upper
surface of the floor tile in order to "suspend" the frame
from the floor tile. The threaded wall 12 in the central
region of the mounting frame 3 is designed to receive the
mounting collar 4, which takes the form of an annular
component which, at any one point around the annulus, is of
generally inverted U-shaped cross-section, as can clearly
be seen in Figure 1.
Thus the mounting collar 4 defines an annular upper
surface 16 having a depending outer wall 17 and a depending
inner wall 18, the inner wall 18 being formed, on its
inwardly directed surface, with a single screw thread
which, in section, resembles a tooth 19 which co-operates
with the external thread 13 on the wall 12 of the mounting
frame to enable the collar 4 to be connected with the
mounting frame by way of the co-operating screw threads.
The mounting collar 4 may therefore be threaded onto the
frame 3 and rotated in order to move the collar up towards
the floor tile 1 until it reaches the position shown in
Figure 2 where the floor tile is effectively "clamped"
between the flange or lip 10 at the uppermost edge of the
frame 3 and the mounting collar 4.
To facilitate the rotation of the mounting collar
a plurality of generally radially outwardly extending webs
20 are provided on the outwardly directed surface of the
wall 18 of the mounting collar 4 such that they are
accommodated within the U-section thereof. Four such
"finger webs" 20 may be provided.
The upper surface 16 of the mounting collar 4 is
provided with four equally spaced apertures 21 at
approximately central positions between the walls 17 and
18, the apertures 21 being designed to receive fixing
screws 22 or the like (see Figure 2) which are passed
through the collar and extend into the floor tile 1 in
order to fix the collar to the floor tile.
Around its periphery at the junction between the
upper surface 16 and the outermost depending wall 17 the
mounting collar is formed with a cut away recess or step
23, by means of which the plenum chamber is mounted
thereon. The plenum chamber 7 is generally of circular
form in plan elevation having a scroll-type inlet adapted
to be connected to ducting through which air is conveyed
towards the outlet where the apparatus is to be mounted.
The plenum chamber has an outlet 24 which is circular and
which is designed to be mounted on the collar 4. The outer
wall of the plenum chamber 7 extends outwardly slightly, as
identified at reference numeral 25, as it extends towards
the outlet 24 and terminates with an inwardly directed lip
26 which is designed to sit within the recess 23 defined at
the outer periphery of the mounting collar 4. The plenum
chamber 7 is designed to be snap-fitted onto the mounting
collar and for this purpose the depending outer wall of the
collar 4 is of slightly lesser thickness at its lower, free
edge than at its upper edge where the recess 23 is defined.
The plenum chamber 7 is mounted on the collar 4 by
aligning the outlet 24 of the plenum chamber with the
mounting collar so that the depending wall 17 passes into
the outlet 24. The inwardly directed lip 26 engages the
outer surface of the depending wall 17 and the wall of the
plenum chamber 7 is deformed outwardly as the chamber is
pushed upwards and onto the mounting collar 4 until the lip
26 snaps into the recess 23 whereupon the plenum chamber 7
is firmly mounted upon the collar 4. The inherent
resilience of the plastics material from which the plenum
chamber 7 is moulded permits flexing of its outer wall so
that it can be mounted on the collar 4 in the manner
described.
Looking now at the components shown above the floor
tile 1 in Figure 1 of the drawings, it will be seen that
the damper/dirt tray or basket 5 is of similar general form
to the mounting frame 3 and is designed to be received
within the mounting frame 3. Thus the basket 5 is of
generally circular form in plan view and has an upper wall
27 formed at its uppermost edge with an outwardly directed
flange 28. The upper wall extends, at its lower edge, into
a downwardly and inwardly extending lower wall 29 which
leads into a base 30 which closes off the bottom of the
basket 5. The basket 5 is, as mentioned, designed to be
received within the mounting frame and is configured such
that upon insertion into to the mounting frame 3 the flange
28 rests upon the step 11 defined by the mounting frame so
that the basket is suspended within the mounting frame.
When inserted in this position the wall 27 is aligned
adjacent the wall 12 of the mounting frame whilst the wall
29 is disposed immediately adjacent the wall 14 of the
mounting frame.
The wall 29 defines eight air inlet apertures 31
which are of rectangular configuration and are equally
spaced around the periphery of the wall at 45 degree pitch.
Each aperture 31 has a circumferential extent of
approximately 18 degrees. The apertures 31 are of
substantially the same size and form as the apertures 15 in
the wall 14 of the mounting frame 3. Thus, when the basket
5 is received within the mounting frame 3 the apertures 31
are designed to be aligned, in a vertical direction, with
the apertures 15. Rotation of the basket 5 within the
mounting frame 3 allows the apertures 31 to be moved with
respect to the apertures 15 between fully aligned positions
where fully open apertures are produced and off-set
positions where the material between the apertures 31 serve
partially or fully to close off the apertures 15. Thus the
rotation of the basket 5 within the mounting frame 3 allows
the variation of the degree of damping i.e. control of the
air flow rate through the apparatus.
The base 30 of the basket 5 defines a T-shaped
upstanding tab 32 which is provided as an aid to assist in
pulling out the basket 5 from within the frame 3.
The basket 5 and the mounting frame 3 are provided
with means for releasably fixing the position of the basket
5 within the frame 3 so as to provide a desired degree of
damping or air flow rate. The releasable fixing means
comprise eight dovetail slots 33 which extend downwardly in
the inwardly directed surface of the wall 12 of the frame
3 from its upper edge. The eight dovetail
slots 33 are spaced around the internal surface of the
wall 12. The circumferential spacing between all bar two
of the slots is 48.2 degrees with the spacing between the
final two slots being 22.6 degrees. It will be appreciated
that with the apertures 31 and 15 being spaced around the
basket 5 and mounting frame 3 at 45 degree spacings, the
locations of the dovetail slots do not correspond precisely
with the locations of the apertures.
The slots 33 are designed so as to receive a
dovetail peg 34 (see Figure 2). The dovetail peg 34
carries an enlarged head at its upper end which projects
above the level of the step 11 defined by the mounting
frame 3 and is designed to be received within a single
aperture 35 which extends through the flange 28 defined at
the upper rim of the basket 5. When the apparatus is
assembled in the manner as shown in Figure 2 with the peg
34 located in one of the dovetail slots 33 so that its head
is accommodated within the aperture 35 in the rim of the
basket 5, the basket 5 cannot be rotated relative to the
mounting frame 3 but can still be lifted out of the frame
3. Thus it will be appreciated that the dovetail slots 33,
the peg 34 and the aperture 35 in the basket 5 serve to
lock the basket 5 in position relative to the frame 3 in
such a way as to provide a predetermined degree of damping
or air flow rate.
With the arrangement of the dovetail slots 33 being
at different angular settings around the frame 3 to the
apertures 15 the appropriate selection of one slot 33 to
receive the peg 34 determines the degree of damping. Each
slot 33 gives a gradually increased or decreased degree of
damping. When the apparatus is initially assembled the
appropriate degree of damping can be selected by locating
the peg 34 in the appropriate slot 33. This then sets the
degree of damping and even if the basket 5 is removed for
cleaning or the like the peg 34 does not have to be removed
and because the enlarged head of the peg 34 projects above
the level of the step 11 defined by the mounting frame 3
the basket 5 can only be reintroduced into the frame 3 in
the same position as that in which it was originally
located i.e. in the position where the head of the peg 34
is received within the aperture 35 in the rim of the
basket. Thus the desired degree of damping is maintained.
The diffuser 6 is of disc-like form having a
diameter of approximately 200mm and a depth of
approximately 20mm. The disc is formed as two halves,
there being an upper half and a lower half each of
approximate equal thickness. The two halves are formed as
moulded plastics components which are then permanently
bonded together to produce a single diffuser disc defining
a plurality of apertures extending therethrough. Each half
of the disc is moulded with co-operating pegs and recesses
and one index peg and recess (of a different size to the
remaining pegs and recesses) for correct mating. As
mentioned above the diffuser disc 6 is designed to be
received within the upper portion of the mounting frame 3.
Figure 3 is a schematic perspective view of the
diffuser disc from which it can be seen that the disc has
a circular central region 36 and a plurality of apertures
37, each of which extends at a tangent to the central part
36 of the disc. Every other tangentially extending
aperture 37 is split into two parts, there being an inner
part adjacent the central part 36 of the disc and an outer
part which extends out towards the periphery of the disc.
Thus in a circumferential direction every other aperture 37
is longer and split into two halves. There are a total of
24 tangentially extending apertures or airways 37 spaced
circumferentially around the disc. The underside view of
the disc corresponds to the view shown in Figure 3 insofar
as the arrangement of the apertures 37 and the central part
36 of the disc are concerned.
The disc 6 is, as previously mentioned, designed to
be accommodated within the upper portion of the mounting
frame 3, seated upon the upper rim of the dirt tray 5, as
illustrated in Figure 2. The disc 6 and the mounting frame
3 are provided with co-operating means for releasably
retaining the disc 6 in position within the mounting frame.
Thus, at one point on its periphery the disc 6 is provided
with upper and lower projecting tabs 38, 39 with a shallow
recess 40 therebetween. The tabs 38, 39 have a
circumferential extent of approximately 13mm.
Diametrically opposite the tabs 38, 39 the disc 6 is formed
with a small circumferentially extending projection 41,
having a circumferential extent of approximately 10mm. The
mounting frame 3 is formed with a slot or aperture 42 which
is designed to accommodate the projection 41. Thus the
aperture 42 serves, when it receives the projection 41, to
prevent rotational movement of the disc 6 within the
mounting frame 3. Opposite the slot or aperture 42 the
mounting frame 3 is provided with a resilient clip 43 in
the form of a depending finger 44 having an enlarged, lower
end 45. The finger 44 is, of course, free to move in the
radial direction at its lower end. The junction between
the wall 9 and the flange 10 of the mounting frame 3
defines a shallow recess or cut out 46 which is designed to
accommodate the upper tab 38 formed on the disc 6.
It will be appreciated that to locate the disc 6
within the mounting frame 3 the disc is positioned such
that the tabs 38, 39 are aligned with the clip 43 and the
edge of the disc carrying the projection 41 is lowered into
the space defined by the upper part of the mounting frame
so that the projection 41 is received within the slot 42.
The diametrically opposite edge is then pressed downwardly
into the opening defined by the mounting frame, the lower
tab 39 causing the resilient finger 44 of the clip 43 to
deflect radially outwardly before it passes, as a snap-fitting,
beneath the enlarged lower end 45 of the finger
whereupon the upper tab 38 is accommodated within the cut
away recess 46 at the upper edge of the mounting frame.
The design is such that the disc is securely "clipped" into
place and cannot rotate relative to the mounting frame due
to the engagement of the projection 41 within the slot 42
with minimum clearance. In addition the upper surface of
the disc 6 lies substantially flush with the top edge of
the mounting frame 3 so as to prevent persons from
tampering with the diffuser disc 6 and possibly removing it
from its mounting location. Means are however provided for
the removal of the disc 6 by authorised personnel.
Thus, adjacent the upper tab 38 and at the radially
outer end of one of the apertures 37 a small recess 47 is
defined within the body of the disc, the recess 47 being
designed to receive a hooked end of a pull-out tool 48
which may be hooked onto the disc and used in order to pull
it out of the mounting frame 3. As the disc is lifted
upwardly the lower tab 39 once again causes the lower end
of the resilient finger 44 to deflect radially outwardly
whereupon it moves passed the enlarged head 45 so that the
disc 6 may be "popped out" from the mounting frame 3.
Figure 6 illustrates, in cross-section, one of the
apertures 37 formed in the diffuser disc 6. As previously
mentioned the disc 6 is formed in two halves which are
permanently bonded together. Thus in Figure 6 the upper
half of the disc is identified by reference numeral 49
whilst the lower half of the disc is identified by
reference numeral 50. It will be observed that the part of
the aperture 37 which extends through the upper half 49 of
the disc 6 extends at an angle of approximately 50 degrees
to the horizontal and has parallel side walls. In
contrast, that part of the aperture 37 which passes through
the lower part 50 of the disc 6 has non-parallel walls and
extends, at the free face of the disc 6 at an angle of
approximately 19 degrees to the vertical (71 degrees to the
horizontal) whilst at the face which is bonded to the upper
half of the disc 6 it extends at approximately 13 degrees
to the vertical (77 degrees to the horizontal). Thus the
part of the aperture 37 formed in the disc portion 50
converges towards the free face. It will also be observed
that the two halves of the aperture 37 extend in opposite
directions so that a flow of air is turned from one
direction to another as it passes through the disc 6.
Whilst the "forwardmost" walls of the upper and lower parts
of the apertures 37 meet at an alignment point 51, it will
be noted that the rearmost walls of the apertures 37 are
off-set at the junction between the upper and lower parts
of the disc 6 so that a step 52 is created. The presence
of the step 52 serves to create turbulence within the flow
of air, the turbulence providing improved air flow
characteristics.
The arrows 53, 54 in Figure 6 illustrate the
general direction in which air flows through the disc when
the disc is mounted in the frame 3 in the orientation
illustrated in Figure 6. It will be observed that air
leaves the diffuser disc 6 in a generally horizontal
direction as illustrated by the arrow 54. The disc 6 is
designed to be mounted within the frame 3 either way up and
Figure 7 is a cross-section through an aperture 37 when the
disc is mounted in the frame 3 the other way up to that
shown in Figure 6 so that what was the upper half 49 of the
disc is located lowermost in Figure 7 whilst what was the
lower half 50 of the disc is shown uppermost in Figure 7.
The symmetrical arrangement of the tabs 38, 39, the clip 43
and the projection 41 and the slot 42 permit the mounting
of the disc 6 either way up within the mounting frame 3.
It will be observed from Figure 7 that when mounted
in the frame 3 in this particular orientation, the disc 6
provides for an air discharge in a substantially vertical
direction, the flow of air being illustrated by the arrows
55, 56. Thus, by simply reversing the orientation of the
disc 6 (using the pull-out tool 48) the air discharge
pattern may be varied between a substantially horizontal
discharge (as shown in Figure 6) and a substantially
vertical discharge (as shown in Figure 7).
It is envisaged that the majority of the components
of the apparatus may be formed from plastics materials.
Thus, the mounting frame 3, the diffuser disc 6, the
mounting collar 4 and the location peg 34 may be formed
from polycarbonate whilst the damper/dirt tray 5 and the
plenum 7 may be formed from polypropylene.
The apparatus is assembled by initially passing the
mounting frame 3 through an opening formed in the floor
tile 1 and then threading the collar 4 onto the frame 3 so
that the tile 1 is sandwiched in position between the
collar and the upper flange of the mounting frame. Screws
22 may then be passed through the collar to secure the
arrangement in place with respect to the tile 1. The
plenum 7 can then be simply snap-fitted onto the mounting
collar 4 and ducting or the like may be mounted on the
inlet of the plenum simply as a push fit. It is envisaged
that the plenum inlet may have an initial relatively narrow
portion which leads into a slightly wider inlet portion
with the two portions being interconnected by a parting
line. If the ducting which is to be connected to the
plenum is of relatively narrow diameter then it may be
push-fitted directly onto the initial inlet portion whereas
if a larger diameter ducting is to be used then the initial
relatively narrow inlet portion may be removed at the
parting line so that the ducting can be push-fitted onto
the relatively larger inlet portion.
The damper/dirt tray 5 is dropped into the mounting
frame 3 and rotated to provide the desired degree of
damping/air flow rate. The location peg 34 is then passed
through the aperture 35 in the rim of the tray 5 and into
one of the dovetail slots 33 formed in the mounting frame
3 thereby providing a predetermined location for the tray
5. The diffuser disc 6 is then snap-fitted into the
opening at the upper end of the mounting frame 3 in the
manner as described with reference to Figure 4, whereupon
it is securely held in place but can, as mentioned, be
removed by way of the pull out tool 48 when it is desired
to invert the disc 6 to provide a different air discharge
pattern. When the damper/dirt tray 5 needs to be removed
for cleaning or maintenance purposes the disc 6 can simply
be pulled out of the frame 3 using the tool 48. Following
cleaning or maintenance the dirt tray 5 can only be
replaced within the frame 3 in the same position as that in
which it was initially located due to the presence of the
upstanding location peg 34. This ensures that upon
replacing the tray 5 the desired damper setting is
retained. The damper setting can, of course, be adjusted
by removing the peg 34, rotating the tray 35 to a new
setting and replacing the peg 34, passing it through the
aperture 35 in the rim of the tray 5 and into a different
dovetail slot 33 in the wall of the frame 3.
It may be necessary in certain situations to mount
the apparatus within a relatively deep concrete slab floor.
This often presents difficulties and the apparatus is
therefore designed with an alternative mounting arrangement
for use with relatively deep concrete slab floors. The
arrangement is illustrated in Figures 8 and 9 of the
drawings. In Figures 8 and 9 a concrete slab floor is
identified by reference numeral 57. It will be appreciated
that it is not possible to pass screws through the mounting
collar 4 into the concrete slab floor. Instead the
apparatus is fixed in position by means of a pair of
mounting clamps 58, one of which is illustrated in each of
Figures 8 and 9.
It will be appreciated that a pair of mounting
clamps 58 are provided at diametrically opposed positions
on the mounting frame 3.
Thus, at diametrically opposed positions the step
11 formed at the junction between the upper and middle
portions of the mounting frame 3 defines bores 59 through
which clamping bolts 60 are passed. The bores 59 are
designed such that the head of a bolt 60 is retained within
the bore with the threaded shank of the bolt passing down
through the bore so as to be disposed adjacent the wall 12
of the mounting frame 3. At positions beneath the bores 59
the wall 12 defines recesses or cut away regions 61 each of
which serves to receive a resilient spring steel mounting
clamp 62. A clamping nut 63 is located on the end of each
of the bolts 60. The resilient spring steel clamp 62 is
configured such that its lower end engages and is urged
against the nut 63 and such that as the bolt 60 is rotated
in a clockwise direction the nut 63 rises up the threaded
shank of the bolt and urges the lower end of the resilient
clamp 62 radially outwardly. A lower region of the clamp
62 carries an outwardly directed barb or projection 64.
When assembling the apparatus using the arrangement
shown in Figures 8 and 9 a sleeve or collar 65 is initially
located within the aperture formed in the concrete slab 57,
that sleeve or collar having a circumferentially extending
recess or ridge 66 disposed at a position corresponding to
the location of the barb 64 formed on the resilient clamp
62. When the apparatus is to be mounted in position the
mounting frame 3 is dropped into the sleeve or collar with
the mounting clamps 62 located thereon in the manner as
shown in Figure 8. Each of the bolts 60 is then rotated so
as to cause to the nut 63 to rise up the threaded shank
until the position shown in Figure 9 is reached. This
urges the lower end of the resilient clamp 62 radially
outwardly until the barb 64 engages the recess 66 formed in
the sleeve or collar 65 and is then retained captive in the
recess. The clamping arrangement using the resilient
clamps 62 locks the complete assembly in place in the
sleeve within the aperture in the concrete slab floor.
The damper/dirt tray 5 may then be dropped into the
mounting frame 3 in the usual way whereupon the upper rim
of the tray 5 serves to conceal and extend over the top of
the heads of the bolts 60. The diffuser disc 6 may then be
mounted in place in the usual way and the threaded collar
4 can be located on the lower most end of the threaded wall
12 with the plenum connected thereto. It will be
appreciated that the mounting arrangement described above
provides a secure yet concealed fixing for locating the
apparatus in position within a floor constituted by a
relatively deep concrete slab.
From the description given above it will be
apparent that the apparatus overcomes a number of problems
associated with existing designs. In particular the design
is "tamper proof" in that the diffuser disc 6 cannot be
removed by hand without the use of the pull out tool. At
the same time, however, it is possible simply and easily to
vary the air discharge pattern by removing and turning over
the disc 6 and to clean and maintain the damper/dirt tray
region. In addition, the correct setting of the damper is
automatically maintained by virtue of the "memory facility"
constituted by the location peg 34 which ensures that the
damper/dirt tray 5 can only be replaced within the mounting
frame 3 in one predetermined position.
The features disclosed in the foregoing
description, in the following claims and/or in the
accompanying drawings may, both separately and in any
combination thereof, be material for realising the
invention in diverse forms thereof.