AU5773801A - Ventilation system - Google Patents

Description

Regulation 3.2 -1-

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT 0 0 0 0 0.0 APPLICANT: SUSTAINABLE AGRICULTURAL MACHINERY DEVELOPMENTS PL NUMBER: PQ 9149/00 FILING DATE: 3/ 8/2000 Invention Title: VENTILATION SYSTEM The following statement is a full description of this invention, including the best method of performing it known to me/us: -2- VENTILATION SYSTEM This invention relates to improvements in ventilation systems and in particular to improvements in exhaust fans and ducted heating and/or air conditioning systems.

It has been found that, generally, where exhaust fans are not operating rather than warm air leaving the space in which the fan is situated and passing to the ceiling space or the like, in fact, cold air enters through the fan blades into the space vented by the fan and this can add to the heating load required for a space.

In ducted air conditioning systems it can be found that when the air conditioning unit is not in operation, that is not passing conditioned air into a volume, then there can be a flow of air through the duct which is detrimental to the temperature of the volume.

The object of the present invention is to provide means in ventilating systems, means whereby flow of air through the system when this is not required is restricted.

In the first aspect of the invention we provide, in association with an airflow provided by a fan, valve means associated with the output of the fan which, when the fan is not in operation, is normally closed but, on operation of the fan, opens to permit air to pass readily through the valve.

In a preferred for of the invention, we provide valve means as mentioned above in which the valve is counter balanced so as to be readily moveable from its closed position when there is no air movement from the fan to its open position when the air is moving in the 20 required direction the arrangement being such that the valve is so balanced to be firmly closed when air tends to flow in the opposite direction.

In preferred aspects, the valve is used in association with an exhaust fan, the valve means associated with the output of the fan which valve means, when the fan is not in operation, K:\WP51 I\Spec\SAMDEVComp.wpd 31/7/01 is normally closed but, on operation of the fan, opens to permit air to pass readily through the fan to be vented.

The invention is also applicable to air-conditioning systems having ducts opening into volumes, where valve means are provided in the air conditioning duct to maintain the duct normally closed but which can, when air is passing through the system, open to effect little restriction to movement through the duct.

It is preferred that the lack of or restriction is by a valve means which is counter balanced so as to be readily moveable from its closed to its open position when the air is moving in the required direction but tends to remain firmly closed when air tends to flow in the opposite direction.

Particularly in the air conditioning aspect of the invention, the device can also be used as a flow control device to enable modification of the total flow through the duct.

In order that the invention may be more readily understood we shall describe, with o. ooreference to the accompanying drawings, various embodiments of the invention.

In these drawings; o Fig 1 shows a first embodiment of the invention in its closed orientation; Fig 2 is a sectional view of the embodiment of Fig 1 showing it in its open condition; Fig 3 is a sectional view somewhat similar to that of Fig 2 showing a modified form of the invention; and Fig 4 is a partial view similar to that of Fig 3 showing the valve closed.

K:\WPSI\Spec\SAMDEVComp.wpd 31/7/01 Each embodiment is shown as being associated with an exhaust fan but it can be applied to other applications as will be described hereinafter.

Exhaust fans are generally located in a ceiling and, when being operated, operate in a manner which causes air to be drawn from the volume in which the ceiling is located to vent, normally into a ceiling space or the like, although such fans can be ducted to an exterior wall, or through the roof.

In the invention, which in this embodiment is used with a fan, not shown, feeding into a ceiling space, we provide a valve member which comprises a cylindrical member or a piece of ducting 10 which is adapted to fit over the fan which member has, at its upper end, a counter balanced valve 20 which is normally closed.

The valve 20 comprises two members which are generally semi-circular in form and the main body portion 22 of which can rest on a valve seat 23 formed from shaping the o surface of the cylindrical member •These members may be made by moulding plastics material, shaping sheet plastics or from sheet metal.

Part way along their length the members 22 are provided with a lug or recess 23 which may be adapted to receive a pivot pin 24 which can be connected to an portion 25 of the duct which can be part of the duct before shaping to provide the valve seat.

There can be a shoulder 26 between the original portion of the duct 25 and the valve seat 20 23 and the pivot point can be adjacent the edge of the original portion.

K:\WP51 I\Spec\SAMDEVComp.wpd 31/7/01 The inner edge 30 of the semi-circular member 21 is at an angle to the remainder of the member and is such that when the member rests against the valve seat, as shown in Fig 1, the inner end 30 lies effectively across portion of the top of the normal end 25 of the cylindrical member The arrangement is symmetrical so that, in normal circumstances, the two semi-circular members rotate about the pivot 24 so that they rest against the valve seat 25 and at this time the inner ends of the inner portions 30 are closely adjacent and the end of the cylindrical member 10 is closed.

The arrangement is such that the portion of the semi-circular member which extends outwardly from the pivot 24 is not substantially heavier than the inner portion 30 which extends inwardly so that where there is a position of no airflow through the duct, the duct is effectively closed.

If necessary the inner portion 30 of each semi-circular member can be weighted to provide the correct balance between the two portions with the portion 21 having a 15 sufficient weight to ensure that it normally remains closed but is still permitted to rotate as will be described hereinafter.

°eoee S• The cylindrical member 10 can satisfactorily be made from a portion of a plastic ducting or can be specifically made so that the thickness of the material is sufficient to provide a good valve seat and, if required, seating material could be located around this but it is not generally deemed to be necessary.

The cylindrical member 10 may be of a sufficient length and size to be located over or to form a duct about the fan.

Very often exhaust fans are simply located directly above an aperture in the ceiling and there is a grille or the like adjacent the ceiling to provide a finished appearance and the K:\WPS l\Spec\SAMDEVComp.wpd 31/7/01 cylindrical member may be adapted to be connected over the grill or connect to a frame attached to the fan.

Under normal circumstances, when the fan is not operating, the semi-circular members 21 adopt the position shown in Fig 1 and there is effectively no flow of air past the fan and into the discharged area notwithstanding pressure or temperature differentials between the two which would generally lead to a movement.

When the fan is operating, however, the air moving in the cylindrical member because of the operation of the fan, causes an increase of pressure beneath the valve member 20 and because of the inequality of areas between the semi-circular outer portions of the members 21 and the inner portions 30, the members will rise permitting air to be passed from the fan into the ceiling space or exhaust ducting associated with the fan.

Because the two semi-circular members are substantially balanced there is no great resistance to the air passing from the fan so the fan operates at close to maximum efficiency.

Of course, once the fan ceases operation, then the weight of the outer portions 22 of the ooooo3 "semi-circular members will cause these to move downwardly to rest on their seats 23 again closing the cylindrical member The embodiment shown in Fig 3 is in a major part identical to that shown in Figs 1 and 2 and similar components have the same references.

In this case we provide a baffle 41 which may be a V-shaped member which extends across the width of the duct, the arms of the V being located beneath the inner portions of the valve members and the angle of the V being such that the upper surfaces closely correspond to the lower surfaces of the inner members when the valve is opened.

\Spec\SAMDEVComp.wpd 31/7/01 The arrangement can readily be seen from Fig 3 that when the fan is operating air from the fan pressurises the area between the fan and the valve of the invention but the Vshaped member tends to protect the inner portions from the action of the air and thus makes the opening of the valve substantially more positive.

s At the same time, the V-shaped member limits the opening of the valve and, as such, controls the flow but also makes the arrangement stable as it is possible to have a relatively strong airflow without the valve inadvertently being fully opened or even opened sufficiently far for the free ends 22 of the members 21 being forced over centre and thus into the position where it is unlikely that they will close normally.

Any air pressure on the valve tends to cause it to become more firmly seated whilst any air passing through the fan into the space will readily cause it to rotate about its pivot to permit this air to pass therethrough.

:"The cylindrical member or duct to which the valve is connected may be provided with coco•S an aperture, slot or the like which enables the power connection for the fan to readily pass s15 therethrough.

It would be possible to provide the tube or duct with a number of possible press outs around the periphery thereof, preferably on the end away from the valve, so that, depending on the point of access of the power to the fan, the duct and valve can be located in any required position to give the best results and a press out portion can be removed for the cable to pass therethrough.

5 If it is required, and if the outer portion of the semi-circular member is substantially heavier than the inner portion, then it is possible to associate with the pivot means a counter weight exterior of the cylindrical member 10 to minimise the pressure within the member 10 to enable the valve to open correctly.

K:\WP51\SpecSAMDEVComp.wpd 31/7/01 The particular form of valve can vary as can the counter balance.

If required, the valve and counter balance could be formed integrally and could be of a plastics material or the like and the actual spacing and location of the counter weight can be designed for operation so that the valve and counter weight occupies a minimum space but permits maximum opening.

Alternatively, the valve, the counter weight and the pivot can be separately formed.

The invention can also be located in ducting and this would be particularly useful in air cooling or conditioning systems but it could also, if required, be used with a ducted exhaust fan.

1o In this case, the valve is located within the duct and may be adapted, when closed, to lie directly across the duct but in a preferred form, is adapted to lie at an angle to the duct :"so that movement of air therethrough is normally restricted. It is preferred that the pivot may be somewhat off centre so that whenair moving in the required direction impacts on the plate, the plate can readily rotate as the pressure of the air on one side is greater s15 than on the other. The arrangement can be such that when the valve is fully open, that it lies substantially along a plane parallel to an axial plane so the restriction of fluid flow is minimal.

In this form of the invention the valve is preferably provided with a pivot which extends on either side of the duct and has located thereon, on one side, an arm which may well have an adjustable counter weight on this, the arm and counter weight acting to normally hold the valve closed.

The preferment for an adjustable counter weight is so that the system can be "tuned" to the particular system with which it is to be used to ensure that the valve readily opens 31/7/01 when a normal flow is established, but has a bias to return it to its shut position when the device ceases to operate.

In this application the valve can also be used to provide a balance arrangement to ensure that the air flow into different volumes is controlled to give an optimum flow. For example, some rooms, such as bedrooms, may require less air than other rooms, such as living rooms, and further because the ducting from the unit to the volumes to be treated can be of different lengths it may be preferred to provide additional throttling at the ducts closest to the unit to restrict the total quantity of air passing through.

This could be done by providing a collar on the duct where the shaft for the valve extends and a collar on the shaft and stops means which limits the maximum rotation of the shaft, and thus the valve, to that required for a particular area.

Preferably, this arrangement is adjustable so that the system can be correctly adjusted on fitting but variations can be made if required at a later time.

o o K:\WP51\Spec\SAMDEVCompwpd 31/7/01

Claims (13)

1. In association with an airflow provided by a fan, valve means associated with the output of the fan which, when the fan is not in operation, is normally closed but, on operation of the fan, opens to permit air to pass readily through the valve.

2. Valve means as claimed in claim 1 in which the valve is counter balanced so as to be readily moveable from its closed position when there is no air movement from the fan to its open position when the air is moving in the required direction the arrangement being such that the valve is so balanced to be firmly closed when air tends to flow in the opposite direction.

3. Valve means as claimed in claim 1 or claim 2 wherein the valve means is located at or adjacent the end of a cylinder which encompasses the fan or a duct in which the fan is located.

4. Valve means as claimed in claim 3 which has a pair of generally semi-circular members each having a larger portion comprising the outer portion of the valve and an inner portion which includes the diametric portion of the semi-circular members, each semicircular member being pivoted about a pivot axis parallel to the diametric edge the relative weights of the two portions being such as to normally maintain the valve closed.

5. Valve means as claimed in claim 4 wherein the valve seats against which the semi-circular members act are inclined at an angle from a transverse plane 5 through the cylinder. o o

6. Valve means as claimed in claim 5 wherein the outer portion of each semi- circular member is at an angle to the inner portion, the angle being effectively the same as the angle of inclination of the valve seat. K:\WP51\Spec\SAMDEVCompwpd 31/7/01

7. Valve means as claimed in any one of claims 4 to 6 wherein there is located in the cylindrical member between the fan and the valve member a baffle which restricts the direct passage of the air from the fan to portion of the semicircular members inwardly of the pivot.

8. Valve means as claimed in claim 7 which in the baffle is of V-shaped form, the included angle of the V being such as to closely receive the inner ends of the semi-circular members when the valve is open.

9. Valve means as claimed in any one of claims 4 to 7wherein each semi-circular member is counter-weighted to provide the required relative weights.

10. Valve means as claimed in claim 9 wherein the counter-weighting is effected by a weight external of the cylindrical member and being associated with the pivot arrangement of the member. o•

11. Valve means as claimed in claim 10 wherein the counter-weight is adjustable. 00

12. Valve means as claimed in any one of claims 9 to 1 wherein when the valve is located in an air conditioning duct the valve can also be used as a flow control 0000*0 device to enable modification of the total flow through the duct, the control being by adjustment of the counter-weight to limit the maximum opening of the valve S°.°in the designed air-flow parameters. 0000 °og0 K:\WP51\Spec\SAMDEVComp.wpd 31/7/01 -12-

13. Valve means substantially as hereinbefore described with reference to the accompanying drawings. DATED this 31 day of July, 2001 SUSTAINABLE AGRICULTURAL MACHINERY DEVELOPMENTS PTY. LIMITED By Its Patent Attorneys A TATLOCK ASSOCIATES I\Spec\SAMDEVComp.wpd