GB2314923A

GB2314923A - Fresh air recirculation unit

Info

Publication number: GB2314923A
Application number: GB9712366A
Authority: GB
Inventors: Kenneth James Woodcock; John William Lee
Original assignee: Individual
Current assignee: Individual
Priority date: 1996-06-29
Filing date: 1997-06-16
Publication date: 1998-01-14
Anticipated expiration: 2017-06-16
Also published as: GB2314923B; GB9613694D0; FR2750479B1; DE19726730A1; FR2750479A1; GB9712366D0

Abstract

A fresh air /recirculation unit (1) adapted to be mounted in or on an external wall of a room or building, comprise a sheet metal carcase (8) having an outer end (12) adapted to be located externally of a room or building, and an inner end (14) adapted to be located internally of a room or building, having a fresh air inlet aperture at its outer end (12); adjustable damper means (16) located downstream of the inlet aperture in the direction of fresh air flow to control the volume of fresh air admitted to the unit (1); a mixing chamber (17) located downstream of the damper means (16) in the direction of fresh air flow having an inlet end (18) and an outlet end (19), into which chamber fresh air and/or recirculated air is admissible; a flow path (20), for air to be recirculated, extending from the inner end (14) of the carcase (8) to the mixing chamber (17); a fan unit (21) having an inlet end (22) sealingly connected to the outlet end (19) of the mixing chamber (17) to draw air to be recirculated along the recirculation flow path (20) and/or fresh air through the inlet aperture, and also having an air outlet end (23); and a filter (24) located upstream of the inner end (14) of the carcase (8) and through which air expelled from the outlet end (23) of the fan unit (21) must pass to reach a discharge aperture (25) at the inner end (14) of the carcase (8).

Description

2314923

TITLE OF INVENTIO

Fresh air recirculation unit.

]BACKGROUND OF THE INVENTIO

Field of the Invention

The invention relates to a unit for both the recirculation of air within a room or building, and the admission of fresh air to a room or building.

Description of the Prior A

Basically, prior art units have been either of a puriely re-circulation type, or a purely fresh air admittance type, or a purely air extraction type. Consequently, users such as restaurants, theatres and other venues to which substantial numbers of persons are normally admitted, have been obliged to purchase, to have maintained, and to find suitable locations for, a multiple number of units.

OBJECT OF THE INVENTION A basic object of the invention is to provide a single unit, requiring a single location point, capable of effecting air circulation and/or fresh air admittance, under control of the user.

SUMMARY OF THE INVENTIO

According to the present invention there is provided a fresh air /recirculation unit adapted to be mounted in or on an external wall of a room or building, comprising a sheet metal carcase having an outer end adapted to be located externally of a room or building, and an inner end adapted to be located internally of a room or building, having:

(i) a fresh air inlet aperture at its outer end; (ii) adjustable damper means located downstream of the inlet aperture in the direction of fresh air flow to control the volume of fresh air admitted to the unit via the inlet aperture; (iii) a mixing chamber located downstream of the damper means in the direction of fresh air flow having an inlet end and an outlet end, into which chamber fresh air and/or recirculated air 2 is admissible; (iv) a flow path. for air to be recirculated, extending from the inner end of the carcase to the mixing chamber; (v) a fan unit having an inlet end sealingly connected to the outlet end of the mixing chamber to draw air to be recirculated along the recirculation flow path and/or fresh air through the inlet aperture, and also having an air outlet end; and (vi) a filter located upstream of the inner end of the carcase and through which air expelled from the outlet end of the fan unit must pass to reach a discharge aperture at the inner end of the carcase.

Thus, depending on the setting of the damper means, a fully closed damper means results in 100% recirculation and no fresh air admittance; a semi-opened damper means results in a mixture typically of 50%/50% recirculated air and fresh air; and a fully opened damper means results in 100%, or thereabouts, fresh air with no, or practically no, recirculation. Indeed when the damper means is open to any extent, a positive air pressure within the room or building results, which is particularly advantageous in some venues such as public houses, cafes, restaurants etc. to cause enhanced dispersion of contaminants such as cigarette smoke and cooking fumes. Furthermore, avoidance of simplistic air extraction avoids dispersal to the atmosphere of warm air and thus avoids heat losses and attendant heating costs. Clearly, the capacity of the unit in accordance with the invention for both air circulation and air admittance is finite, and obviously for larger size rooms or buildings, it would be necessary to install multiple units in accordance with the invention.

Preferably, the fan unit incorporates a variable speed fan rather than an on/off fan. It is also preferred for the fresh air inlet aperture of the carcase to be provided with a weather louvre, and the inner end of the carcase to be provided with a grille. The fan unit preferably incorporates a backward curved, centrifugal fan.

3 Preferably, damper control is effected manually, eg by a push/pull rod.

The unit may additional incorporate a heater which is preferably electrically powered with thermostatic control, and conveniently located in the mixing chamber.

The carcase is preferably of rectangular section, preferably comprising two telescopic sleeves whereby the overall length of the carcase may be adjusted for different wall thicknesses. With this arrangement it is preferred for flanges, of greater dimension than the telescopic sleeves, to be provided so that surfaces of the flanges that are orthogonal to the sleeves may seat against internal and external surfaces of the wall of the room or building in to which the unit is fitted as a perimeter seating flange around the aperture which needs to be provided in the wall to accommodate the unit.

The invention will now be described in greater detail, by way of example, with reference to the accompanying drawings, in which:

Figure 1 is a front elevation of a fresh air/recirculation unit in accordance with the invention; Figure 2 is a side elevation of Figure 1, in the direction of arrow A, showing the unit fitted, in situ, into a wall; is Figure 3 is a Section, to an enlarged scale, on the line B - B of Figure 1; and Figure 4 is a section, to an enlarged scale, on the line C C of Figure 1.

In the drawings a fresh air/recirculation unit 1 is adapted to be mounted in or on an external wall 2 of a room or building, the wall comprising an outer brickwork leaf 3, having an external surface 4, a thermally insulated cavity 5, and an inner leaf 6 of brickwork or blockwork having an internal surface 7.

The unit 1 comprises a rectangular sheet metal carcase 8 consisting of an inner sleeve 9 that telescopes into an outer sleeve 10 to accommodate a range of distances "D" between surfaces 4 and 7, so that a rectangular aperture 11 corresponding to the carcase dimensions, is cut into the leaves 3 and 6. Thus, the outer part 10 has outer end 12, located externally of a room 13, and an inner end 4 14 adapted to be located internally of the room 13.

Basically, and in accordance with the invention, the unit 1 has a fresh air inlet aperture 15 at its outer end 12; an adjustable damper means 16 located downstream of the inlet aperture 15 in the direction of fresh air flow, to control the volume of fresh air admitted to the unit via the inlet aperture 15; a mixing chamber 17 located downstream of the damper means 16, in the direction of fresh air flow, having an inlet end 18 and an outlet end 19, into which chamber 17, fresh air and/or recirculated air is admsisible; a flow path 20 for air to be recirculated, extending from the inner end 14 of the carcase 8, to the mixing chamber 17; a fan 6nit 21 having an inlet end 22 sealingly connected to the outlet end 19 of the mixing chamber 17 to draw air to be recirculated along the recirculation flow path 20 and/or fresh air through the inlet aperture 15, and also having an air outlet end 23: and a filter 24 located upstearn of the inner end 14 of the carcase 8 and through which air expelled from the outlet end 23 of the fan unit 21 must pass to reach a discharge aperture 25 at the inner end 14 of the carcase 8.

The fan unit 21 incorporates a variable speed fan, whilst the fresh air inlet aperture 15 of the carcase is provided with a weather louvre 26 and the inner end 14 of the carcase 8 is enlarged beyond the dimensions of the aperture 11 to define a flange 27 that constitutes a seating surface that is orthogonal to the longitudinal axis of the telescopic sleeves 9 and 10 to engage wall surface 7, whilst the sleeve 10 is provided with an orthogonal flange 28 providing a seating surface 29 to engage the wall surface 4.

As can be seen from Figure 3, the damper means 16 comprises five damper elements 30 each mounted on a rotary spindle 31 under manual control by a push-pull rod (not shown) to set the damper elements between fully open, fully closed and intermediate positions. The damper unit 16 is carried by a rectangular, sheet metal sub-assembly 32 fitted into the end of sleeve 10 and also carrying the flange 28.

At its end remote from the discharge aperture 25, the inner telescopic sleeve 9 is provided with inwardly directed deflector plate 33 (best seen in Figure 3), whilst a sub-assembly 34 located within the inner telescopic sleeve 9 carries the fan unit 21 by a transverse securing bracket 35 attached to opposite sides of the sub-assembly 34, to which bracket 35 the fan unit 21 is attached by bolts on axes 36, with the filter 24 carried by the opposite end of the sub-assembly 34 to that with which the fan unit 21 is associated. As can best be seen in Figure 4, the recirculation air flow path is defined between the outside of the sub-assembly 34 and the inside of the inner sleeve 9, whilst side grilles 38 cover inlet apertures into the recirculation air flow paths 20 and a grille 39 covers the inner end 14 of the unit 1.

Electrical power to the fan unit 21 is provided via an external connection 40, with lead 41 to the fan unit 21 and lead 42 to an indicator light 43, whilst a manually operable, rotary rheostat control 44 serves for user-adjustment of the speed of the fan unit 21, whilst the unit is also preferably provided, upstream of the fan unit 21, with a 1.5 Kw electric coil heater 45 which has a pre-set cut out switch (not shown).

1 6

Claims

CLAIMS:

1. A fresh air /recirculation unit adapted to be mounted in or on an external wall of a room or building, comprising a sheet metal carcase having an outer end adapted to be located externally of a room or building, and an inner end adapted to be located internally of a room or building, having:

(i) a fresh air inlet aperture at its outer end; (ii) adjustable damper means located downstream of the inlet aperture in the direction of fresh air flow to control the volume of fresh air admit&d to the unit via the inlet aperture; (iii) a mixing chamber located downstream of the damper means in the direction of fresh air flow having an inlet end and an outlet end, into which chamber fresh air and/or recirculated air is admissible:

(iv) a flow path, for air to be recirculated, extending from the inner end of the carcase to the mixing chamber; (v) a fan unit having an inlet end sealingly connected to the outlet end of the mixing chamber to draw air to be recirculated along the recirculation flow path and/or fresh air through the inlet aperture, and also having an air outlet end; and (vi) a filter located upstream of the inner end of the carcase and through which air expelled from the outlet end of the fan unit must pass to reach a discharge aperture at the inner end of the carcase.

2. A unit as claimed in Claim 1, wherein the fan unit incorporates a variable speed fan.

3. A unit as calimed in Claim 1 or Claim 2, wherein the fresh air inlet aperture of the carcase is provided with a weather louvre.

4. A unit as claimed in any preceding Claim, wherein the inner end of the carcase is provided with a grille.

7

5. A unit as claimed in any preceding Claim, wherein the fan unit incorporates a backward curved, centrifugal fan.

6. A unit as claimed in any preceding Claim, comprising manual control means for the damper means.

7. A unit as claimed in Claim 6, wherein the manual control means is a push/pull rod.

8. A unit as claimed in any preceding Claim, incorporating a heater.

9. A unit as claimed in Claim 8, wherein the heater is electrically powered.

10. A unit as claimed in Claim 8 or Claim 9, whirein the heater is subject to thermostatic control.

11. A unit as claimed in any one of Claims 8 to 10, wherein the heater is located in the mixing chamber.

12. A unit as claimed in any preceding Claim, wherein the carcase is of rectangular section.

13. A unit as claimed in any preceding Claim, wherein the carcase comprises two telescopic sleeves.

14. A unit as claimed in Claim 13, wherein flanges, of greater dimension than the telescopic sleeves, are provided so that surfaces of the flanges that are orthogonal to the sleeves may seat against inner and outer surfaces of the wall of the room or building into which the unit is fitted as a perimeter seating flange around the aperture which needs to be provided in the wall to accommodate the unit.

15. A fresh air/recirculation unit substantially as hereinbefore described with reference to the accompanying drawings.