[0001] The present invention relates to ventilation arrangements, particularly for ventilating
a garage, workshop, factory unit or other indoor enclosures prone to contain noxious
gases.
[0002] Modern garage doors provide a relatively air-tight seal. This is generally advantageous
but leads to the situation that if a vehicle is driven into a garage and then the
door is immediately closed, the garage will be filled with exhaust gases which cannot
escape. There are, however, many other indoor enclosures which are liable to contain
noxious gases.
[0003] We have now devised arrangements for overcoming the above-described problem.
[0004] In accordance with the present invention, there is provided a ventilating installation
which comprises a door installed or for installing in an entrance of a building enclosure,
and an extraction fan assembly arranged for energisation upon closure of the door,
to expel air from within the enclosure through an outlet formed in the door.
[0005] The extraction fan assembly is preferably mounted at or adjacent the top of the door.
In the case of a roller shutter door, the fan assembly is preferably mounted below
the roller housing of the door: preferably one of the horizontal slats of the door
is provided with a grille or a perforated section, to register with the fan assembly
outlet. In the case of an up-and-over door, a grille or perforated section is provided
in the door, to register with the fan assembly outlet.
[0006] The fan assembly is preferably energised once the door reaches its closed position.
This may be sensed by de-energisation of the door motor, in the case of a powered
door, or by a switch positioned so that it actuated as the door reaches its closed
position.
[0007] The fan assembly may be arranged so that it remains energised for a predetermined
period of time. Preferably however, a sensor of one or more noxious gases (e.g. carbon
monoxide) is mounted in or adjacent the fan assembly, to sense the concentration of
such gas or gases in the outlet air flow: the fan remains energised until the sensed
concentration of the noxious gas or gases falls below a predetermined threshold value.
[0008] Additionally, an occupancy detector (e.g. a passive infra red detector) may be mounted
in the garage or other enclosure, and arranged to energise the fan assembly upon detecting
the presence of a person in the enclosure, if the noxious gas sensor senses greater
than a given value of such gas or gases in the enclosure.
[0009] Preferably the installation further comprises an inlet for fresh air, to replace
the air extracted by the fan assembly. Preferably this air inlet is installed at a
position remote from the extraction fan assembly, preferably at or adjacent the opposite
end of the garage, or other enclosure. In the case of a large enclosure, such as a
factory unit, a fan may be provided in the fresh air inlet, to positively introduce
the fresh air: preferably the inlet fan assembly switches on and off with the extraction
fan.
[0010] An embodiment of the present invention will now be described by way of example only
and with reference to the accompanying drawing, the single Figure of which is a schematic
sectional view through a roller-shutter garage door which has an extraction fan assembly.
[0011] Referring to the drawing, there is shown a garage doorway in which a roller shutter
door is installed. The roller shutter door comprises a housing 10 mounted behind a
lintel L extending across the top of the garage doorway. The door itself comprises
a number of horizontal slats 12, adjacent slats being pivotally coupled together.
A roller 14 is mounted within the housing 10 and the door is wound around the roller
14, extending through a slot 11 in the lower side of the housing 10. An electric motor
(not shown) is mounted within the housing to turn the roller in order to raise or
lower the door. U-section channels are mounted down the opposite sides of the doorway
and the opposite edges of the door run in these, providing a seal between the edges
of the door and the doorway. A remote control system is provided to enable the vehicle
driver to control the raising and lowering of the door.
[0012] In accordance with the invention, an extraction fan assembly 20 is installed in the
garage, below the roller shutter housing 10 and behind the door itself (when lowered).
The extraction assembly comprises a casing in which a fan impeller 22 is rotatably
mounted: an electric motor (not shown) is provided to drive the impeller 22. The fan
casing has an inlet 24 in its rear, directed towards the garage interior, and an outlet
26 in its front. One of the slats of the roller shutter door is formed with a grille
or perforated section 16: when the door is fully lowered and therefore closed, the
grille 16 is registered with the outlet 26 of the fan assembly.
[0013] The motor of the fan assembly is provided with a controller which is connected to
the control system of the roller shutter door. The arrangement is such that as the
door reaches its closed position, and the door motor is switched off, the fan motor
is energised to extract air and exhaust gases from within the garage and expel them
from the garage through the grille 16. The fan motor may be arranged to run for a
predetermined (preferably adjustable) length of time.
[0014] Alternatively or in addition, a carbon monoxide sensor 18 may be mounted in the air
flow passage of the fan assembly, and arranged to maintain the fan motor running until
the sensed concentration of carbon monoxide falls below a predetermined threshold
value.
[0015] Additionally, a passive infra red (PIR) sensor 28 may be mounted in the garage and
arranged to switch the fan motor on upon detecting the presence of a person in the
garage, whilst the door is closed, if at the same time the carbon monoxide detector
senses that the concentration of carbon monoxide is above a given value.
[0016] In any event, the garage is provided with an inlet 30 for fresh air, to replace the
air extracted by the fan assembly. The inlet 30 is installed at a position remote
from the fan assembly, preferably at or adjacent the opposite end of the garage and
preferably adjacent ground level. Preferably the air inlet includes a filter through
which the fresh air passes.
[0017] Whilst the invention has been described in use with a roller shutter door, it may
instead be used with up-and-over doors, whether powered or manually raised and lowered.
Where the up-and-over door is powered, the fan motor may be energised upon the drive
motor of the door switching off, as the door reaches its closed position: alternatively,
a switch may be provided on the door frame and arranged to be actuated as the door
reaches its closed position, in order to energise the fan motor; the latter arrangement
is employed where the door is manually operated.
[0018] It will be appreciated that the installations which have been described ensure that
the atmosphere within the garage will be cleared rapidly of vehicle exhaust gases
and will accordingly facilitate the safety of the garage.
[0019] Whilst the invention has been described when installed in a garage, particularly
a domestic garage, the invention may be installed in any building enclosure liable
to contain noxious gases, for example a workshop, factory unit or other industrial
premises.
1. A ventilating installation which comprises a door installed or for installing in an
entrance of a building enclosure, and an extraction fan assembly arranged for energisation
upon closure of the door, to expel air from within the enclosure through an outlet
formed in the door.
2. A ventilating installation as claimed in claim 1, in which said extraction fan assembly
is mounted at or adjacent the top of said door.
3. A ventilating installation as claimed in claim 1, in which said door comprises a roller
shutter door.
4. A ventilating installation as claimed in claim 3, in which said extraction fan assembly
is mounted below a roller housing of said door.
5. A ventilating installation as claimed in claim 4, in which said door comprises a series
of horizontal slats, one of which is formed with a grille or perforated section to
register with an outlet of said extraction fan assembly.
6. A ventilating installation as claimed in claim 1, in which said door comprises an
up-and-over door.
7. A ventilating installation as claimed in claim 6, in which said door is provided with
a grille or perforated section to register with an outlet of said extraction fan assembly.
8. A ventilating installation as claimed in any preceding claim, arranged for said extraction
fan assembly to be energised in response to said door reaching its closed position.
9. A ventilating installation as claimed in claim 8, in which said door is powered by
a motor and said installation is arranged for said extraction fan assembly to be energised
in response to de-energisation of said motor.
10. A ventilating installation as claimed in claim 8, further comprising a switch positioned
to be actuated as said door reaches its said closed position.
11. A ventilating installation as claimed in any preceding claim, arranged for said extraction
fan assembly to remain energised for a predetermined period of time.
12. A ventilating installation as claimed in any preceding claim, further comprising a
sensor of one or more noxious gases mounted adjacent said extraction fan assembly
and arranged so that said extraction fan assembly remains energised until the sensed
concentration of said noxious gas or gases falls below a predetermined threshold value.
13. A ventilating installation as claimed in claim 12, further comprising an occupancy
detector which is arranged to energise said extraction fan assembly upon detecting
the presence of a person in said building enclosure to which said door is fitted,
if said sensor of noxious gas or gases senses a concentration of such gas or gases
greater than a given value.
14. A ventilating installation as claimed in any preceding claim, further comprising an
inlet for fresh air to replace air extracted by said extraction fan assembly.
15. A ventilating installation as claimed in claim 14, in which said air inlet is installed
at a position, in said building enclosure in which said door is fitted, remote for
said extraction fan assembly.
16. A ventilating installation as claimed in claim 14 or 15, in which said air inlet is
provided with a fan assembly for the positive introduction of fresh air.
17. A ventilating installation as claimed in claim 16, arranged for said inlet fan assembly
to switch on and off with said extraction fan assembly.