GB2155170A - Adjustable ventilators - Google Patents

Abstract

The adjustable laminar flow ventilator comprises a housing 2 connected to an air supply duct by a spigot 4. Air entering the ventilator flows through a honeycomb mesh 16 into a perforated spigot 17 which contains a baffle plate 24. The position of the baffle plate, and thus the rate of air flow through the ventilator can be adjusted by operating a screw 22. The lowermost part of the chamber 2 is bounded by a perforated fascia 3 through which air is introduced to the space e.g. a room to be ventilated in a laminar flow. The ventilator can be mounted in a ceiling or wall. <IMAGE>

Description

SPECIFICATION Improvements in or relating to a ventilator The invention relates to a ventilator, and more particularly relates to a ventilator adapted to be mounted on a wall or ceiling of a building, the ventilator being connected to a conduit supplying ventilating air.

Many different ventilators have been proposed previosly to be mounted on a ceiling or wall and adopted to be connected to a duct supplying ventilation air to be passed through the ventilator into the room or space to be ventilated. Many prior ventilators are of a generally square configuration, thus presenting a substantially square fascia to the room or space to be ventilated, and have a rearwardly extending cylindrical spigot adapted to be connected to the duct supplying ventilating air.

In connection with previous ventilators the air flow of the ventilating air emanating from the ventilator depends, to a large extent, upon the construction of the exposed fascia. Often the pattern of the air flow is such that turbulance is caused, and this results in the intermixing of the fresh air being introduced to the room or space to be ventilated, and stale air already present in the room or space. A consequence of this is that any dust or other airborne particles present in the room or space are spread throughout the entire room or space being ventilated. This can be disadvantageous, especially in areas such as "clean rooms" in electronic manufacturing plants, hospital operating rooms, and the like, where there is a special requirement for a continuous supply of fresh clean air.

Thus recently attempts have been made to make ventilators which provide air to a room to be ventilated as a laminar flow, that is to say as an air flow in which adjacent layers of the flow do not mix, except at a molecular scale.

The present invention seeks to provide an adjustable ventilator which may produce a laminar flow.

According to this invention there is provided a ventilator adapted to be mounted on a wall or ceiling, and adapted to be connected to a conduit supplying ventilating air, to supply ventilating air to a room or space bounded by said wall or ceiling, said ventilator comprising a housing defining a chamber; a spigot for connecting said chamber to a conduit supplying ventilating air, a perforated extension of said conduit extending into said chamber; a baffle plate contained within said perforated conduit and having external dimensions substantially corresponding to the internal dimensions of the conduit, the baffle plate and perforated conduit being relatively adjustable to increase the area of the perforated conduit directly exposed to air entering said perforated conduit through said supply spigot, and thus to control the rate of supply of ventilating air; said chamber is directed into the room or space to be ventilated.

In one embodiment the baffle plate is movable axially within the perforated conduit.The perforated conduit will be fixed in position. In an alternative embodiment, however, the baffle plate may be fixed and the perforated conduit may be movable axially relative to the baffle plate, thus altering the proportion of the perforated conduit exposed below the baffle plate.

Preferably said baffle plate is perforated, and advantageously the percentage free area of the perforated spigot is greater than the percentage free area of the baffle plate. In one embodiment the perforated spigot has approximately 42% free area and a perforated baffle has approximately 28% free area.

Conveniently the perforated spigot is cylindrical and the baffle plate is substantially circular.

Preferably the spigot is closed, at the end thereof located within the chamber, by a face plate, and said face plate may be perforated, and may be 28% free area.

In a preferred embodiment the face plate supports means defining an internally screw threaded bore which accommodate a screw, the baffle plate being fixedly mounted on the screw, the arrangement being such that rotation of the screw adjusts the position of the baffle plate relative to the face plate, thus adjusting the area of the perforated spigot exposed to air introduced to the ventilator.

Preferably said spigot incorporates a flow equalising grid, and conveniently the flow equalising grid is of honeycomb construction.

Advantageously the fascia is releasably connected to said housing to provide access to the interior of the housing.

Conveniently the fascia has a substantially flat region exposed to the space to be ventilated, said substantially flat region being perforated.

In order that the 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 perspective view, partly cut away, of a ventilator in accordance with the invention, and Figure 2 is a transverse cross sectional view of the complete ventilator taken on the line ll-ll of Figure 1.

A ventilator 1 in accordance with the present invention consists of a generally rectangular housing 2, presenting a substantially square fascia 3 at its underside and having, on its top surface in the position illustrated, a cylindrical spigot 4 adapted to be connected to a conduit supplying ventilating air.

The conduit 4 is associated with a mechanism 5 for adjusting the rate of flow of air through the ventilator, as will be described hereafter in greater detail.

In use of the ventilator air flows through the spigot 4, into the housing 2, and leaves the ventilator through the fascia 3.

The housing 2 has a substantially rectangular upper wall 6 which, when the ventilator is in a position illustrated in Figure 1, is horizontal. There are four depending side walls 7 each terminating with an outwardly directed flange 8. Frame members 9 are provided, each having an inwardly di rected flange 10 which is located adjacent the above-mentioned flange 8 and is pop-rivetted thereto. The frame member 9 is provided, at its lowermost edge, with a contoured flange 11 adapted to abut a ceiling or wall on which the presently described ventilator will primarily be used in a ceiling mounted position.

Each frame member 9 defines, on its inner surface, a substantially "U" shaped recess 12.

The fascia 3 comprises a tray like element having a planar lower region 13 which is perforated. Preferably the perforations constitute a regular array of circular holes, but the perforations may have many possible shapes, sizes and relative positions. The tray like element has a peripheral upstanding side wall 14 which carries protruding screws 15 which, as can be seen from Figure 2, engage in the "U" shaped recesses 12 and the frame members 13.

The fascia 3 is connected to the frame in a hinged manner and is retained by spring clips, thus enabling the fascia 3 to be readily lowered to provide access to the interior of the housing 2.

The spigot 4 is constituted by a cylindrical sheet metal element having, at its lower end, an outwardly directed flange 15. The spigot is located in position in an aperture formed in the upper wall 6 of the housing 2, with the flange 15 secured to the underside of said upper wall 6. The spigot 4 contains a honeycomb mesh 16 which defines a plurality of air channels each substantially parallel with the axis of the spigot 4.

A depending cylindrical perforated spigot 17 is provided, which depends from the lower end of the spigot 4, the upper regions of the perforated spigot 17 being spot welded 18 to the lower interior part of the spigot 4. The perforated spigot 17 is provided with an outwardly directed flange 19 at its lower end, and a circular face plate 20 is spot welded to the flange 19. The face plate 20 effectively closes the lowermost end of the perforated spigot 17. The face plate 20 is perforated and has 28% free area.

At the centre of the face plate 20 a rivet 21 is provided which defines a central vertical internally threaded bore. A screw 22 is provided in position in said threaded bore, the screw extending upwardly. Adjacent its uppermost end two nuts 23 which are threadedly engaged on the screw 22 trap between them a substantially circular baffle plate 24. The baffle plate 24 has a diameter substantially equal to the internal diameter of the perforated spigot 17 and is snugly received within the perforated spigot 17. The baffle plate is perforated and has 28% free area.

As the screw 22 is rotated, so the screw will rise or fall relative to the rivet 21, and consequently the perforated baffle plate 24 will also rise or fall within the tubular spigot 17.

In operation of the device the spigot 4 is connected to a conduit supplying ventilating air. The air will flow through the honeycomb mesh 16, and thus a plurality of substantially parallel flows will be created through the channels formed in the honeycomb mesh 16. The air will then flow into the space above the perforated baffle plate 24. Some of the air will pass through the perforated baffle plate 24, and the remainder of the air will flow laterally through that part of the perforated spigot 17 which is located above the perforated baffle plate 24.

The air flowing through the perforated baffle plate 24 will eventually pass either through the portion of the perforated spigot lying beneath the perforated baffle plate 24, or through the perforated face plate 20.

When the perforated baffle plate is in a fully elevated position, as shown in Figure 2, the perforated area exposed to the air flowing through the airflow equalising honeycomb element 16 is at a minimum. However, as the baffle plate 24 is lowered, by actuation of the screw 22, an increasingly greater area of the perforated spigot 17 will be directly exposed to the air flowing through the flow equalising honeycomb element 16. It is to be noted that the perforated spigot has a free area of 42%, compared with the free area 28% of the perforated baffle plate 24, and thus, as the perforated baffle plate 24 is lowered, for a constant air supply pressure, there will be an increasing rate of flow of air through the ventilator. Thus the adjustable perforated baffle plate constitutes an air flow rate con troi means.

When the baffle plate 24 is in the fully lowered position, a maximum flow rate of air through the ventilator will be experienced.

As will be appreciated, regardless of the position of the baffle plate, air will enter the housing 2 through the perforated spigot and through the perforated face plate. The configuration of the housing will direct this air flow downwardly, and the air will leave the housing through the fascia 3. Due to the above-described construction of the ventilator the air leaving the fascia will have a substantially laminar flow.

It will be appreciated, from the foregoing description, that the preferred embodiment of the invention comprises a ventilator which can be mounted on a ceiling (or on a wall) and which can be connected to a conduit supplying ventilating air, the rate of flow of air through the ventilator being adjustable, the air leaving the ventilator with a substantially laminar flow.

Claims (16)

1. A ventilator adapted to be mounted on a wall or ceiling, and adapted to be connected to a conduit supplying ventilating air, to supply ventilating air to a room or space bounded by said wall or ceiling, said ventilator comprising a housing defining a chamber; a spigot for connecting said chamber to a conduit supplying ventilating air, a perforated extension of said conduit extending into said chamber; a baffle plate. contained within said perforated conduit and having external dimensions substantially corresponding to the internal dimensions of the conduit, the baffle plate and peforated conduit being relatively adjustable to increase the area of the perforated conduit directiy exposed to air entering said perforated conduit through said supply spigot, and thus to control the rate of supply of ventilating air; said chamber being provided with a fascia through which air introduced to the chamber is directed into the room or space to be ventilated.

2. A ventilator according to claim 1, wherein the baffle plate is movable axially within the perforated conduit.

3. A ventilator according to claim 1 or 2 wherein said baffle plate is perforated.

4. A ventilator according to claim 3 wherein the percentage free area of the perforated spigot is greater than the percentage free area of the baffle plate.

5. A ventilator according to claim 4 wherein the perforated spigot has approximately 42% free area and a perforated baffle has approximately 28% free area.

6. A ventilator according to any one of claims 1 to 5 wherein the perforated spigot is cylindrical and the baffle plate is substantially circular.

7. A ventilator according to any one of claims 1 to 6 wherein the spigot is closed, at the end thereof located within the chamber, by a face plate.

8. A ventilator according to claim 7 wherein said face plate is perforated.

9. A ventilator according to claim 8 wherein said face plate has 28% free area.

10. A ventilator according to any one of claims 7 to 9 whereinthe face plate supports means defining an internally screw threaded bore which accommodate a screw, the baffle plate being fixedly mounted on the screw, the arrangement being such that rotation of the screw adjusts the position of the baffle plate relative to the face plate, thus adjusting the area of the perforated spigot exposed to air introduced to the ventilator.

11. A ventilator according to any one of claims 1 to 10 wherein said spigot incorporates a flow equalising grid.

12. A ventilator according to claim 11 wherein the flow equalising grid is of honeycomb construction.

13. A ventilator according to any one of the preceding claims wherein the fascia is releasably connected to said housing to provide access to the interior of the housing.

14. A ventilator according to any one of claims to wherein the fascia has a substantially flat region exposed to the space to be ventilated, said substantially flat region being perforated.

15. A ventilator substantially as herein described with reference to and as shown in the accompanying drawings.

16. Any novel feature or combination of features disclosed herein.