AU767871B2 - Smoke spill ventilator - Google Patents

Description

P/00/0il 128/5/9 1 Regulabon 3.2(2)

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT 4 *44k 4* 4 4 4 4* 4 4

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44**44 Application Number: Lodged: Invention Title: SMOKE SPILL VENTILATOR The following statement is a full description of this invention, including the best method of performing it known to :-us SMOKE SPILL VENTILATOR FIELD OF THE INVENTION The present invention relates generally to ventilation equipment. In particular, the invention concerns ventilators of the type used for exhausting smoke from a building. Such ventilators, which are commonly known in the art as "smoke spill ventilators", are typically designed for mounting on the roof of a building such that, during a fire, smoke may be extracted from within the building and expelled away from the building. It will therefore be convenient to describe the invention in relation to that 10 example application but it should be understood that the invention is oooo o intended for more general application and use.

Smoke spill ventilators may be powered, incorporating a motor driven fan, or may be unpowered. Powered ventilators are commonly referred to as "smoke spill fans". Unpowered ventilators may be called "smoke spill vents". The present invention is equally applicable to both types of ventilator.

BACKGROUND OF THE INVENTION Smoke spill fans typically include a motor driven extraction fan mounted within a housing and having an upwardly facing ventilation opening. A non-return discharge damper having a number of damper flaps (typically two) may be arranged over the ventilation opening to prevent wind and rain entering the ventilator, and hence the building, when the fan is not in use. During operation of the fan, the air pressure produced by the fan forces the flaps open to allow smoke laden air to be expelled from the building.

Smoke spill systems are manufactured in accordance with various standards, such as Australian/New Zealand standard 1668.1:1998 "The use of ventilation and airconditioning in buildings, Part 1: Fire and smoke control in multi-compartment buildings".

During a fire, a smoke spill fan may fail due to high temperatures, and in that event the above standard requires that the smoke spill path (through the ventilator) remains open so that smoke may be naturally ventilated through the smoke spill system. The damper flaps of the ventilator must therefore remain in an open position in the event of failure of the fan.

Because the installation of smoke spill ventilators involves significant capital cost, it is desirable for smoke spill systems to be able to perform a secondary function in more general building ventilation. In that function, the damper flaps should close automatically once the fan has been deactivated. Such a dual function or "dual mode" ventilator would therefore need to latch open the flaps when operating in "smoke spill S 10 mode" and close the flaps automatically when operating in general "ventilation mode". It would therefore be desirable for a facility to be provided for switching between operating modes.

Smoke spill fans are typically designed to extract high volumes of smoke laden air. They therefore run at high speed, and thus tend to be noisy. General ventilation, however, may be achieved at a lower volume, such that a slower speed may be used. It would therefore also be desirable for the ventilator to include a dual speed fan, or to operate in .''.conjunction with such a fan, and to automatically operate in "smoke spill mode" (incorporating a latching mechanism) when the fan operates at 20 high speed and operate in "ventilation mode" (without a latching mechanism) when the fan operates at low speed.

SUMMARY OF THE INVENTION One aspect of the present invention accordingly provides a smoke spill ventilator including: a housing having a ventilation opening, at least one flap hingedly connected to the housing and at least partially overlying the ventilation opening, the flap(s) being movable between a closed position, in which airflow through the opening is substantially inhibited, and an open position, in which airflow through the opening is permitted, and flap latching means for holding the flap(s) in a latched position between the open and closed positions.

3 It will be appreciated that any position of the flap(s) other than when fully closed will allow some airflow through the ventilation opening.

A whole range of "open" positions is therefore possible, depending on the design of the particular ventilation system. The latched position may lie anywhere between and including the fully open position for a particular system and the fully closed position.

In one embodiment the latching means includes a first member and a second member. In this embodiment the first and second members are releasably coupled in the latched position. Preferably, the first member includes a ratchet bar having at least one retaining recess associated with .the latched position. The second member may include a latching pin arranged to engage the retaining recess.

The retaining recess may be in the form of an indentation or notch in an otherwise relatively flat surface or edge of the ratchet bar.

Alternatively, the retaining recess may be in the form of a gap between two projections or teeth of the ratchet bar. Any suitable shape of recess may be used as long as it serves to retain the latching pin.

Advantageously, the ratchet bar includes a plurality of recesses :corresponding to a plurality of available latched positions for the flaps.

The latching pin may be of any suitable form, as long as it serves the function of latching within the retaining recess, or one of the retaining recesses. For example, the pin may be of any suitable cross section, such as round, square, triangular, etc., and it may be fixed to or formed integrally with the relevant structure or component by any suitable method. The pin may be fixed at one of its ends only, or at both ends such that it extends between two opposing surfaces. Other variations would become apparent to a person skilled in the art and these are also considered to fall within the scope of the present invention.

In a typical smoke spill ventilator the flaps are movable towards the open position by positive air pressure below the flaps and are automatically returnable to the closed position under the action of gravity.

4 Another aspect of the present invention provides a smoke spill fan including a smoke spill ventilator as described above in combination with a motor driven fan mounted within the housing. The fan may generate the positive air pressure necessary to push the flaps open. In this embodiment the latching means is operable to hold the flaps in the latched position in the event of failure of the motor or fan, thereby meeting the Australian/New Zealand standard for smoke spill fans.

Such a combination unit allows for convenient installation on, or within, the roof of a building. An alternative, however, may be to mount a S 10 smoke spill vent (unpowered) on the roof of the building and mount the fan separately within the building. The fan may then be connected to the vent by suitable ducting.

In one embodiment the smoke spill ventilator (powered or unpowered) includes two flaps arranged in butterfly fashion. The latching means may be configured to operate between the flaps. Preferably, a ratchet bar is pivotably connected to a first of the flaps and a latching pin is fixed to or forms part of the second of the flaps.

In an alternative embodiment, however, a separate ratchet bar may be pivotably connected to each flap and a corresponding latching pin, may be fixed to the housing of the ventilator. In a further alternative, the arrangement may be reversed such that the ratchet bars are pivotably connected to the housing and the latching pins are fixed to or form part of the flaps.

In a still further alternative, the ratchet bar or bars may be fixed to or form part of either the flaps or the housing, and the latching pin may be a movable member associated with the other part. In effect, the latching pin may then operate in much the same manner as a convention pawl used in known ratchet mechanisms.

In one embodiment, retaining recesses are provided in an operative edge of the ratchet bar and that operative edge rests upon the latching pin. In use, the latching pin engages one of the retaining recesses by pivotal movement of the ratchet bar relative to the latching pin.

In a preferred embodiment, the operative edge of the ratchet bar includes a first portion and a second portion. The first portion is operative over a first range of movement of the flaps which extends from the closed position to a predetermined open position. The second portion is operative over a second range of movement of the flaps which extends beyond the first range of movement. In this embodiment, the retaining recesses are provided in the second portion of the ratchet bar S 10 corresponding to the second range of movement of the flaps. This feature is useful in "dual mode" ventilators having a two-speed fan wherein a smoke spill mode is provided by running the fan at high speed and a general ventilation mode is provided by running the fan at low speed.

In this implementation of the invention the predetermined open position is selected such that the fan's low speed (ventilation mode) produces sufficient pressure to open the flaps within the first range of movement only, whilst the fan's high speed (smoke spill mode) produces sufficient pressure to open the flaps to within the second range of movement. The latching means is thus effective when the fan is in smoke spill mode but is ineffective when the fan is in ventilation mode.

The smoke spill ventilator advantageously includes release means for disengaging the latching means when desired. In embodiments where the latching means includes a ratchet bar having an operative edge resting upon a latching pin, the release means may act to pull the operative edge away from the latching pin. In this way, the latching pin is disengaged from the retaining recess of the ratchet bar.

In one embodiment the release means includes an electrically operated actuator which, preferably, may be remotely controlled from within the building. Alternatively, any other suitable means may be provided to pull the operative edge of the ratchet bar away from the latching pin, or vice versa, thus allowing the flaps to close.

The release means may also be used to implement a "dual mode" facility, even where a single speed fan is employed. In a general ventilation mode, the release means may be activated at the same time as power is applied to the fan motor. In the preferred embodiment, the operative edge of a ratchet bar is pulled away from the latching pin such that the latching pin cannot engage a retaining recess of the ratchet bar, and latching of the flaps is not possible. The flaps may thus automatically close when the fan is turned off. In a smoke spill mode, the release means is not activated, thus allowing the latching pin to engage within a retaining recess. The flaps are then held in a latched position after the fan motor stops. The flaps may be released upon subsequent activation **of the release means.

BRIEF DESCRIPTION OF THE DRAWINGS To assist the further understanding of the invention, reference will now be made to the accompanying drawings which illustrate a preferred embodiment. It is to be appreciated that this embodiment is given by a way of illustration only and the invention is not to be limited by this illustration.

20 In the drawings: Figure 1 illustrates a side view of a smoke spill ventilator in S•accordance with an embodiment of the present invention, in a rest position; Figure 2 shows a side view of the smoke spill ventilator of Figure 1, with the flaps held in a latched position; and Figure 3 shows a side view of the smoke spill ventilator of Figure 1, and showing the operation of the release means.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT Figures 1 to 3 show a smoke spill ventilator 10 intended for mounting on a roof of a building or the like. The ventilator 10 includes a housing 12 having a ventilation opening 14. Overlying the ventilation opening 14 are two damper flaps 16 and 18 which are hingedly connected to the housing 12 by axel rods 20 and 22 respectively. The flaps 16 and 18 are made of a rigid, light weight material that is able to withstand high temperatures, for example, aluminium.

When the ventilator 10 is not in use the flaps 16 and 18 remain at rest in a closed position as shown in Figure 1. They are sloped downwardly away from the axel rods 20 and 22 so that rain water is drained away from the ventilation opening 14. In the embodiment shown, a flexible seal 24 connects the flaps 16 and 18 to prevent rain water passing between them.

The smoke spill ventilator 10 may include a motor operated fan (not shown) within the housing 12, or it may be constructed as an unpowered smoke spill vent. In the latter case, the ventilator 10 may be connected by a suitable ducting system to a remotely located fan.

In use, the fan produces a positive air pressure below the flaps 16 S 15 and 18, causing them to move from the closed position as shown in Figure 1 to an open position as shown in Figures 2 and 3. A wind band or shield 26 may be provided to screen the flaps 16 and 18 from wind, particularly when they are in an open position.

The smoke spill ventilator is also provided with a flap latching 20 means 27 in the form of a ratchet bar 28 and associated latching pin The ratchet bar 28 is pivotably connected to the flat 16 by a bolt 32 and bracket 34. The latching pin 30, which is also a bolt, is fixed to the flap 18 via a bracket 36.

In the embodiment shown, the ratchet bar 28 has an operative edge 38 having a first portion 40 and a second portion 42. The second portion 42 includes four retaining recesses 44 which, as will be explained below, serve to engage the latching pin 30. Because the ratchet bar 28 is loosely held by its bolt 32, the operative edge 38 rests upon the latching pin 30 under the influence of gravity.

In use, air pressure from the fan forces the flaps 16 and 18 upwardly and this causes the latching pin 30 to slide along the operative edge 38 of the ratchet bar 28. Depending upon the pressure/ flow 8 characteristics of the fan, and hence the extent to which the flaps 16 and 18 open, the latching pin may stay within the first portion 40 of the operative edge 38 or it may pass to the second portion 42. As will be appreciated by studying the drawings, a first range of movement of the flaps 16 and 18 will be associated with the first portion 40 of the operative edge 38 and a second range of movement will be associated with the second portion 42 of the operative edge 38. A predefined flap position will thus be associated with a predefined point of the operative edge 38 separating the first and second portions 40 and 42 respectively.

If the fan opens the flaps 16 and 18 only within the first range of movement, they will automatically close when the fan stops. This may be *o useful for providing general ventilation of the building.

If the fan opens the flaps 16 and 18 to within the second range of movement, such that the latching pin 30 is within the second portion 42 of the operative edge 38 of the ratchet bar 28, the latching pin 30 may engage any one of the retaining recesses 44. In the embodiment shown, the four retaining recesses 44 correspond to four possible latched .positions of the flaps 16 and 18. When the fan stops, for example due to failure during a fire, the flaps 16 and 18 would begin to close. However, 20 in doing so, the latching pin 30 will engage the first of the recesses 44 it encounters, -thereby holding the flaps at the latched position. Figure 2 shows an example of the flaps being held at a latched position, as may occur in the event of failure of the fan. Smoke may then be naturally vented through the ventilation opening 14.

The smoke spill ventilator 10 is also provided with release means 46 in the form of an electrically operated actuating motor 48, an arm and a cable 52. The actuating motor 48 may be remotely operated from within the building, thus facilitating remote resetting of the ventilator after testing, false alarms, or the like.

Figures 1 and 2 show the release means 46 in an inoperative state whilst Figure 3 shows the release means 46 in operation. The actuating motor 48 rotates the arm 50, which pulls the ratchet bar 28 upwardly by 9 means of the cable 52. This causes the latching pin 30 to disengage from the recess 44, thus allowing the flaps 16 and 18 to return to the closed position as shown in Figure 1. The actuating motor 48 can then be deenergized, allowing the arm 50 to lower again.

The release means 46 may also be used to render the latching means 27 inoperative. If power is applied to the actuating motor 48 at the same time as power is applied to the fan motor, the ratchet bar 28 is lifted such that the latching pin 30 is prevented from engaging any of the retaining recesses 44. This feature may be useful to enable the smoke 10 spill ventilator 10 to operate in a general ventilation mode, wherein one wants the flaps 16 and 18 to close automatically when the fan is switched off.

Finally, it will become apparent to those skilled in the art that various modifications or additions may be made to the above described latching means and to the smoke spill ventilator as a whole. For example, the ratchet bar 28 shown in the drawings is curved and the operative edge 38 is an upper edge of an elongate slot formed within the ratchet bar 28.

The ratchet bar may, however, have be straight and the operative edge 0: may have been the bottom edge of the bar. Such modifications and additions are considered to fall clearly within the spirit and scope of the p .n present invention.

Claims (13)

1. A smoke spill ventilator including: a housing having a ventilation opening, at least one flap hingedly connected to the housing and at least partially overlying the ventilation opening, the flap(s) being movable between a closed position, in which airflow through the opening is substantially inhibited, and an open position, in which airflow through the opening is permitted, and flap latching means for holding the flap(s) in a latched position '•between the open and closed positions.

2. A smoke spill ventilator as defined in claim 1 wherein the latching means includes a first member and a second member, the first and second members being releasably coupled in the latched position.

3. A smoke spill ventilator as defined in claim 2 wherein the first member includes a ratchet bar having at least one retaining recess associated with the latched position and the second member includes a latching pin arranged :eooo o to engage the retaining recess. °°lea 9 9

4. A smoke spill ventilator as defined in claim 3 wherein the ratchet bar includes a plurality of retaining recesses corresponding to a plurality of available latched positions. A smoke spill ventilator as defined in any one of claims 2 to 4 wherein the first member is connected to the flap and the second member is connected to the housing or another flap. r° 11

6. A smoke spill ventilator as defined in any one of claims 1 to including two.flaps arranged in butterfly fashion, the latching means being configured to operate between the flaps.

7. A smoke spill ventilator as defined in claim 6 when appended to claim 4, wherein the ratchet bar is pivotably connected to a first of the flaps and the latching pin is fixed to a second of the flaps.

8. A smoke spill ventilator as defined in claim 7 wherein the retaining recesses are provided in an operative edge of the ratchet bar and the operative edge of the ratchet bar rests upon the latching pin, such that in use the latching pin engages one of the retaining recesses by pivotal movement of the ratchet bar.

9. A smoke spill ventilator as defined in claim 8 wherein the operative edge of the ratchet bar includes a first portion and a second portion, the first o. portion being operative over a first range of movement of the flaps which extends from the closed position to a predetermined open position and the second portion being operative over a second range of movement of the S flaps which extends beyond the first range of movement, and wherein the second portion of the ratchet bar includes the retaining recesses. 9 A smoke spill ventilator as defined in any one of the preceding claims, further including release means for disengaging the latching means.

11. A smoke spill ventilator as defined in claim 10 when appended to claim 8 or 9, wherein the release means acts to pull the ratchet bar away from the latching pin such that the latching pin disengages from the retaining recess.

12. A smoke spill ventilator as defined in claim 10 or 11 wherein the release means includes a remotely operable actuator. 12

13. A smoke spill ventilator as defined in any one of the preceding claims wherein the flap(s) are movable towards the open position by positive air pressure below the flap(s) and are returnable to the closed position under the action of gravity.

14. A smoke spill fan including a smoke spill ventilator as defined in any one of the preceding claims in combination with a motor driven fan mounted within the housing. A smoke spill fan including a smoke spill ventilator as defined in claim 13 in combination with a motor driven fan mounted within the housing for generating the positive air pressure, the latching means being operable to hold the flap(s) in the latched position in the event of failure of the motor or fan.

16. A smoke spill ventilator substantially as herein described with reference to the accompanying drawings. DATED this 26th day of February 2003 FANTECH PTY LTD WATERMARK PATENT TRADE MARK ATTORNEYS 290 Burwood Road Hawthorn Victoria 3122 Australia P8A° P16383AUAU RLT/SH