GB2194035A - Ventilator apparatus for buildings - Google Patents

Abstract

Ventilator apparatus in which the flow output of a fan 11 is used to pressurise the apparatus and displace flaps 17 against a bias 26 to vary the ratio of air recirculated (via ducts 12 and 15) to discharge and intake ventilation air flows (via ducts 12 and 14 or ducts 16 and 15). The fan may alternatively be arranged to depressurise the apparatus, and the apparatus may provide for either of said ventilation air flows only. Low or no fan induced flow allows recirculation flow at least whereas at higher flow rates a control flap in the flow causes increase of ventilation flow. <IMAGE>

Description

SPECIFICATION Ventilator apparatus for buildings This invention concerns ventilator apparatus for buildings.

Ventilator apparatus is known which com- prises a flow directing flap arrangement which is manually hydraulically, or electric-mechani cally positionable to permit air to be recircu lated within the building, or to permit a venti lating flow to be drawn into or forced out of the building for ventiiating the building, by an electric fan. However, such apparatus has dis advantages particularly relating to improper or fautly setting or actuation of the flap arrange ment and problems in controlling the apparatus to provide required conditions within the building.

To avoid such disadvantages and problems, it has been proposed to provide ventilator apparatus with two fans, one to determine the recirculatory flow and the other to determine the ventilating flow. This dual-fan apparatus has the disadvantages of manufacturing cost and complexity, running costs and increased risks of, for example, fan motor or switchgear failure due to the need for the extra fan.

An object of the invention is to enable said disadvantages and problems to be avoided or reduced.

According to the present invention there is provided ventilator aparatus, in or for installa tion in a building, comprising a fan and a flap arrangement movable between a first condi tion, wherein fan rotation generates at least a recirculation flow through the apparatus, for recirculating air within the building, and a sec ond condition wherein fan rotation causes at least a ventilation flow through the apparatus, for ventilation of the building; and character ised in that the flap arrangement is exposed to, and movable towards the second condition by, a pneumatic thrust caused by the fan; and in that the flap arrangement is biased towards the first condition irl opposition to said thrust, so that for at least part of the output range of the fan, the ratio of ventilation flow to recircu lation flow increases automatically with in crease of said thrust.

In particular, the invention further provides ventilator apparatus comprising a flow junction between at least three air flow paths; means to cause a forced flow of air along a first of said paths and said junction; and a flap ar rangement movable between a first condition, wherein said forced flow flows also along a second of said paths and air flow along a third of said paths is obstructed, and a sec ond condition wherein the obstruction to flow along the third path is reduced; and character ised in that the flap arrangement is movable toward said second condition by a pneumatic thrust caused by said -fan and is biased to wards said first position in opposition to said thrust, so that the positioning of the flap arrangement is at least partially determined by the amount of said thrust.

The flap arrangement preferably comprises one or more flaps disposed at said junction, which flap or flaps is or are exposed and- re- spond directly to said thrust. However, the flap arrangement may comprise qne or more flow controlling flaps disposed at said junction and operatively associated with, e.g. mechanically connected to, a further flap directly exposed and responsive to said thrust for moving the flow controlling flap or flaps.

The apparatus may provide a fourth path at said junction, and the flap arrangement may.

serve to provide a variable restriction to flow along the fourth path.

A preferred form of the invention provides ventilator apparatus, for mounting in a roof of a building, comprising a ventilation outlet .or riser path, a discharge path and an- extractor path, which paths meet at a junction con- trolled by a flap arrangement, and an extractor fan to impel air through the extractor- path to the junction so as to impinge on -the flap arrangement, and wherein the flap -arrangement is biased so that at low fan speeds the arrangement deflects at least a subs.tantial proportion of the flow of impelled airato the discharge path, and is movable by said impingement impelled air against said bias at higher fan speeds to reduce obstruction to the impelled flow flowing up into the ventilation outlet or riser path.

A ventilation intake or downtake path may be-provided so as to be permanently open to the discharge path, or so as to be at. least partially obstructable by the flap arrangement so that this obstruction is reduced in unison .with obstruction to flow in the ventilationMout- let or riser path.

The flap arrangement may comprise a.plural- ity of flaps to control flow in duplicates-df some of the paths, which flaps may -act:;c.o.o- peratively to provide obstruction-to the flow in one of said paths.

Said bias is preferably provided by grnv.ita- tidnal force on the flap arrangement or a mass connected to the flap arrangement,.but may be provided, at least partially, by resilient means such as a tension spring' and said bias is preferably adjustable.

The or each flap may comprise a plurality of portions e.g. to control flow in respective paths, and said portions may be unequal in area.

The flaps, or members cooperating with the flaps, may be adjustable to limit the maximum extent to which any path can be blocked;-so that irrespective of the position or condition of the flap arrangement there exists at all times at least a mihimum ventilation flow andZor--re- circulation flow whilst the fan isrunning~ is running: The paths may be at least partially defined by ductwork. A portion or portions'of said ductwork between adjacent paths may be thermally conductive to permit heat exchange from the flow along one of said adjacent paths to the flow along the other paths.The ductwork may include a drop panel held by release means responsive to failure of a- power supply for the fan to release the drop panel and thereby provide an emergency opening to one or more- of said paths. Fur--- thermore, the flap arrangement may be ar ranged so that any such power supply failure will permit or cause the flap arrangement to assume an emergency condition in which one or more of said paths or an emergency venti lation path is open.

The apparatus ie preferably.provided with heating means to heat at least one of said flows, and/or filter means to filter one of said - flows .

The invention includes an installation and/or a building incorporating said apparatus, and the apparatus may be arranged to draw air -ihto the building from a space between the roof and a transparent cover arranged to trap cover solar cover arranged to trap solarlradia- tion and roof-loss heat for -warming the air.

Further preferred and advantageous features of the invention will become apparent--from the following description, referring to the ac companying diagrammatic drawings, of examples of: the invention. In the drawings: Figure 1 shows, in vertical section-, a first embodiment of the invention; Figure 2 is a view similar to:Fig. 1 of a second embodiment of the invention; Figure 3 shows an enlarged detail of the first embodiment; Figure 4is a perspective view of a lower or internal portion bf ventilator apparatus of the invention; Figure 5 is a sectional view of a -third-em- bodiment; Figure 6 is a sectonal view of a fourth em :embodiment; Figure 7 is a perspective view Of a flap arrangement of the fourth embodiment; and Figure 8 is a-sectional view of a fifth em - bodiment.

In first and second embodiments, the appa ratus is mounted on a roof~10 of a buildipg and generally comprises an electric motor powered variable speed fan 1 f in a very short extractor duct 12 to impel air from within the building along an extractor path through the duct 12 to a junction 13; a riser duct 14 above the duct 12; a pair of discharge ducts 15 extending from opposite sides of the junc tion 13; -a pair Of intake ducts 16 which ex- tend, from external inlets= 16-A, along opposite sides of the duct 14 towards the-ducts 15 and a flap arrangement which comprises a pair of flaps 17.The flaps are biased so that they assume a horizontal position (Fig. 3) to close or obstruct entry to an outlet path defined by the riser duct 14 and to leave open entry to discharge paths defined by the discharge ducts 15 when the fan runs a low speed; and so that as the fan speed is increased, to increase the air flow and thus increase a- pneumatic- thrust exerted on the flaps, they move against said bias progressively towards a -ver- tical or near vertical condition in which they offer minimum obstruction of the riser duct and maximum obstruction of the discharge ducts. Stops, not shown, may be provided to limit movement of the flaps and thus the maximum and minimum obstruction.The flaps are shown in Figs. 1 and 2 in an intermediate position assumed under a particular moderate fan speed wherein some air is recirculated within the building via the ducts 12 and 15, some; air is extracted from the building via the ducts 12 and 14, and expelled via can external outlet 14A, and some fresh air is drawn into the ducts 16 and admixed with the recirculated air in the ducts 15 for blending warm recirculated air with cooler fresh ventilation air.

The speed of the fan may thus be -controlled to give automatic control of temperature within the building.

The first and second embodiments differ pri marily in that in the first embodiment the intake ducts 16 define intake paths which are permanently open to the discharge ducts 15, whereas in the second embodiment the flap arrangement obstructs the intake ducts when the flaps are in or near the horizontal position as indicated partially in broken lines in Fig. 2.

In both embodiments each flap comprises two portions on opposite sides of the pivotal axis 23 of the flap, which portions may be of unequal-area, one portion serving to obstruct the duct 15 and the other portion 20 serving to obstruct the duct 14 in conjunction with the portion 20 of the other flap. One or both of the portions 20 may have an adjustable end piece 21, as shown in Fig. 3, to permit adjustment of a minimum ventilation flow gap 22 between the portions 20 in the horizontal position.

The pivotal axis 23 about which each flap turns may be offset from the flap as indicated in Fig. 3. The axis may conveniently be pro vided by short trunnions provided by or on the flap and sockets or supports provided by walls 24 of the apparatus in or on which the trunnions engage; alternatively the axis 23 may be provided by a pivot on which the flap is mounted, which pivot may extend outside the wail 24 to carry an arm on which a weight 25 is mounted adjustably to provide, and permit adjustment of, said bias, as indi cated in Fig. 4.

As an alternative to or in addition to the weight 25, each flap may have mounted, optionally adjustabty, thereon a bias weight 26 as indicated in Fig. 3.

These embodiments may be simplified to in clude only one of each- of said ducts 15 and 16, e.g. by dividing the apparatus and provid ing a duct wall along the broken line 27 in Fig. 3, and, of course, using a smaller fan. If required, intake duct 16 or ducts may be omitted or separated from said junction 13 and duct 15 by a wall 28 indicated in. broken lines in Fig. 3.

These embodiments, whilst being illustrated in a orientation in which the ventilation flows are vertical to serve as roof mounted ventilators, may be arranged for mounting in any required orientation e.g. for wall mounting so that said flow are horizontal or inclined, with suitable repositioning of the bias weights or substitution or supplementation thereof by resilient bias means such as springs.

The ducts may be varied in shape, relative positioning and length to suit path and other requirements. E.g. the duct-12 may be of negligible length and provided simply by a hole in a wall 29 of the apparatus, so that the extractor path extends through the hole to the junction.

Further, the flap arrangement may comprise separate, optionally mechanically connected, flaps (instead of a flap or flap incorporating respective portions) to control the ventilation and recirculation flows.

Instead of the fan being arranged to pressurise the junction, the fan and ducts may be arranged so that the fan de-pressurises the junction, with suitable re-arrangement of the flap arrangement so that it responds, against the bias, to a pneumatic force which increases in magnitude with decrease in pressure in the junction, for example as indicated in the third embodiment shown in Fig. 5.

In this embodiment, the fan 11 is disposed in the discharge duct 1 5 to draw air into the junction 13 through an extractor 12, for recir-.

culation, and through a ventilation intake duct 16, for ventilation, according to the positioning of the flap arrangement 30 which responds, against a bias provided in- any suitable manner as hereinbefore set forth, to increasing fan output to reduce the obstruction of the duct 16.

The flap arrangement 30 comprises a flow control flap 17 at said junction 13 and a flow responsive pendant flap 31 at-the outlet of the discharge duct 15, which flaps 17 and 31 are-connected by a mechanical linkage 32 arranged so that as the flap 31 is displaced by said flow to reduce the restriction of the duct 15 the flap 17 is lowered to restrict the duct 12 and reduce restriction to the duct 16.

Furthermore, the flap arrangement and ductwork may be simplified, for example, as shown in Fig. 6. In the fourth embodiment a single duct 40 provides an upper portion 16B, providing the intake path, and a lower portion 12A providing the extractor path. The lower portion 1 2A provides extractor openings 42.

to admit air for recirculation. The fan 11 is disposed at the junction 13 to force air into discharge ducts 15.

The flap arrangement comprises a flap. 17 to restrict the intake path, which flap 17 is provided laterally with upstanding -extensions 43 (Fig. 7) which serves as slide valve mem- bers for obstructing the openings 42 and thus the extractor path. The extensions 43 are preferably spaced a few millimetres from the adjacent surfaces of the duct 40.

The flap arrangement is biased,. e.g. by the weight 25, towards a condition in which the extractor path is unrestricted; and the flap is movable downwards by suction -from the:fån in the direction of arrow A. This embodiment may be modified as partially indicated in broken lines in Fig. 6 to include further ductwork 44 providing an outlet or riser duct 14, which may be obstructable by a further portion 17A of the flap 17.

In all embodiments, the ductwork may incor- porate a panel 50 or panels which is or are releasable to provide an emergency path 51, in the event of the power supply to the fan being interrupted for more than a.predeter-.

mined time, for example, as indicated in.

broken lines in Figs. 1 and 5.

However, the ductwork and flap-arrangement may be arranged to provide such an emergency air flow or discharge path, for example, as provided in the fifth embodiment shown in Fig. 8. This embodiment is partially similar to the third embodiment, in that the fan 11 is disposed in the discharge duct 15 and the flap arrangement comprises a flow responsive flap 31 which is disposed at the outlet and connected by mechanical linkage 32, which is disposed at the outlet, to the flow control flap 17 at the junction 13 and is partially similar to the fourth embodiment in that the ductwork provides a single duct 4013, an upper portion 16B of which provides the intake path and a lower portion 12B of which provides the extractor path.However said. intake and extractor paths lead from. respective open ends in opposite directions to said junction; and said flap 17 is movable about a substantially central axis by said linkage from a first condition in which it obstructs the intake. path, as shown in Fig. 8,to a second condition indicated in broken lines in which it obstructs the extractor path, via intermediate conditions in which both said paths are open to the discharge 15. This arrangement has the advantages that ioads on the linkage are mini final due to the balanced nature of the flap 17, and that emergency ventilation can be provided simply by biasing the arrangement, e.g.

by a weight 52, to an emergency condition in which the flap 17 is vertical (or approximately so) so that air can flow along the length of the duct 4013. The movement of the flap arrangement into the emergency condition under normal circumstances can be blocked, e.g. by a stop device 53, which stop device -is is.releas- able by control means responsive to failure of an electrical power supply to the fan, and which stop device is undirectionally effective so that pneumatic thrust from the fan can drive the flap 31 past the stop device and out ofthe discharge duct, to resume normal oper ation automatically when power is restored.

Functionally equivalent automatic emergency ventilation means can be incorporated into the other embodiment, e.g. by employing solenoid tensioned bias springs to provide the-normal working bias instead of bias weights 25, 26 and by weighting the flap or flaps to-assume a condition in which a direct emergency air flow path is provided in the event of the fan ceasing to operate and the working bias being removed by relaxation of the solenoid.

In all ernbodiments, the degree of maximum obstruction may be set or adjustably deter mined e.g. as hereinbefore -set forth in relation to the first or second embodiments; the pro vision of a riser duct for expulsion of air from the building and control of the flow there through by the flap arrangement are optional; and the apparatus may be arranged for instal lation in any required orientation, e.g. for wall mounting, as previously mentioned with refer ence to the first and second embodiments.

A cover may be provided to prevent ingress of rain and/or birds, and air distribution trunk ing may be connected to the -ducts.

- The apparatus is simple to construct, relia ble, relatively inexpensive, and, in use, is eas ily set up to achieve a necessary automatic progression between recirculation and ventila tion by control of the fan, without needing further subsequent attention or control.

For example, for livestock housing it is pre férable to provide at all times rates of flow which are sufficient to minimise the risks of pockets or zones of poor air circulation arising- in a building without giving rise two undue cool ing, so that the flaps may be biased to delay moving from the recirculating condition until the fan output isquite high, whilst the degree of obstruction to ventilation fiow may be re stricted to ensure sufficient ventilation for the building; so that at high fan outputs the addi tional ventilation flow is utilis-ed primarily for cooling and the fan is controlled according to the need for such cooling.To minimise heat losses during operation in-the recirclating con diction, the ductwork is preferably arranged so that incoming ventilation air is warmed by heat conducted through a thermally conductive part of the ductwork which is warmed by out- going air, especially at low ventilation flow rates; and the ducts may be divided or pro vided with flow deflectors- to enhance such heat exchange at low ventilation flow rates.

For buildings used for storing or growing vegetables, the apparatus is preferably ar ranged to give-the required degree of air recir culation with no- or minimal ventilation flow (i.e. maximum obstruction of the ventilation path or paths) until such time as. cooling is required. When cobling is required the fan is preferably controlled so that if the external air temperature is above a predetermined. minimum temperature e.g. 1"C, maximum flow output is provided to reduce the internal temperature as quickly as possible; whereas if the external air temperature is below said minimum, an intermediate level fan output is provided to -blend ventilation air with recirculated air in proportions sufficient to avoid excessively cool air being released into the building.

In all embodiments, the air flow or flows discharged into the building from the apparatus may be warmed, particularly in winter at low ventilation flow rates, by heating-means, such as an electric-heater 60, incorporated into the apparatus, e.g. as indicated-in Fig. 1; the ventilation air- inlet flow may be drawn,.

particularly in winter, from a solar-heat collection space 61 between a transparent covering 62 and the roof 10 as indicated in Fig. 2, which covering 62 may be movable or removable; and air drawn from within the building for recirculation may be filtered by an intake filter- 63 of porous material which is reieasably attached, e.g. by a clamping ring 64, to the apparatus, especially in winter when relatively high recirculation to ventilation air flow ratios are employed for most of the tine. The apparatus may employ any combination of such warming, heat saving and filtering arrangements, or all thereof as indicated for example in Fig. 8. The duct to which the filter is filtered may be shaped, e.g. flanged to assist the retention of the filter on the apparatus, and flow directing means. may be provided to direct the flow or flows of air expelled from the apparatus.

Claims (24)

1. Ventilator aparatus, in or for installation in a building, comprising a fan and a flap arrangement movable between a first condition, wherein fan rotation generatates at least a recirculation flow through the apparatus, for recirculating air within the building, and a second condition wherein fan rotation causes at least a ventilation flow through the apparatus, for ventilation of-the building; and characterised in that the flap arrangement is exposed to, and movable towards the second condition by,.- a pneumatic thrust caused by the fan; and in that the flap arrangement is biased towards the first condition in opposition to said thrust, so that for at least part of the output range of the fan, the ratio of ventilation flow to recirculation flbw increases automatically with increase of said thrust.

2. Ventilator apparatus as claimed in Claim .1 wherein said ventilation flow is expelled from an external outlet for extraction of air from the or a building.

3. Ventilator apparatus as claimed in Claim 1 wherein said ventilation flow is drawn into said apparatus from an external inlet for injection of air into the or a building.

4. Ventilator apparatus as claimed in Claim 3 wherein the apparatus is arranged to provide a further ventilation flow to an external outlet for extraction of air from the or a building.

5. Ventilator apparatus as claimed in Claim 1, 2, 3 or 4 comprising means responsive to failure of a power supply to the fan to open an emergency ventilation flow path through the apparatus.

6. Ventilator apparatus comprising a flow junction between at least three air flow paths; means to cause a forced flow of air along a first of said paths and said junction; and a flap arrangement movable between a first condition, wherein said forced flow flows also along second of said paths and air flow along a third of said paths is obstructed, and a -second condition wherein the- obstruction to flow along the third path is reduced; and characterised in that the flap arrangement is movable toward said second condition by a pneumatic thrust caused by said means and is biased towards said first position in opposition to said thrust, so that the positioning of the flap arrangement is at least partially determined by the amount of said thrust.

7. Ventilator apparatus as claimed in Claim 6 wherein the flap arrangement comprises one or more flaps disposed at said junction, which flap or flaps is or are exposed and respond directly to said thrust.

8. Ventilator apparatus as claimed in Claim 6 the flap arrangement comprises one or more flow controlling flaps disposed at said junction and operatively associated with connected to a further flap directly exposed and responsive to said thrust for moving the flow controlling flap or flaps.

9. Ventilator apparatus as claimed in Claim 6, 7 or 8 arranged to provide a fourth path to the junction.

10. Ventilator apparatus as claimed in Claim 9 wherein the flap arrangement serves to provide a variable obstruction to flow along the fourth path.

11. Ventilator apparatus, for mounting in a roof of a building, comprising a ventilation outlet or riser path, - a discharge path and an extractor path, which paths meet at a junction controlled by a flap arrangement, and an extractor fan to impel air through the extractor path to the junction so as to impinge on the flap arrangement, and wherein the flap arrangement is biased so that at low fan speeds the arrangement deflects at least a substantial proportion of the flow of impelled air to the discharge path, and is movable by said impingement of impelled air against said bias at higher fan speeds to reduce obstruction to the impelled flow flowing up into the ventilation outlet or riser path.

12. Ventilator apparatus as claimed in Claim 11 wherein a ventilation intake or downtake path is provided so as to be permanently open to the discharge path, or so as to be at least partially obstructable by the flap arrangement so that this obstruction is reduced in unison with the obstruction to flow in the yen- tilation outlet or riser path.

13. Ventilator apparatus as claimed in Claim 11 or 12 wherein the flap arrangement comprises a plurality or flaps to control flow in duplicates of some of the paths, which flaps act cooperatively to provide obstruction to the flow in one of said paths.

14. Ventilator apparatus as claimed in any one of Claims 6 to 13 wherein the or each flap comprises a plurality of portions to control flow in respective paths.

15. Ventilator apparatus as claimed in any one of Claims 6 to 14 wherein the flaps, or members cooperating with the flaps, are adjustable to limit the maximum extent to which any path can be blocked, so that irrespective of the position or condition of the flap arrangement there exists at all times at least a minimum ventilation flow and/or recirculation flow whilst the fan or means is operating.

16. Ventilator apparatus as claimed in any one of Claims 6 to 15 wherein the paths are at least partially defined by ductwork having a portion or portions between adjacent paths which is thermally conductive to permit heat exchange from the flow along one of said adjacent paths to the flow along the other paths.

17. Ventilator apparatus as claimed in any one of Claims 6 to 16 and comprising a drop panel held by release means responsive to failure of a power supply for the apparatus to release the drop panel and thereby provide an emergency opening to one or more of said paths.

18. Ventilator apparatus as claimed in any one of Claims 6 to 17 wherein the flap arrangement is arranged so that a power supply failure will permit or cause the flap arrangement to assume an emergency condition in which one or more of said paths or an emergency ventilation path is open.

19. Ventilator apparatus as claimed in any preceding claim wherein said bias is adjustable and is provided by gravitational force on the flap arrangement or a mass connected to the flap arrangement, or by resilient means such as a tension spring.

20. Ventilator apparatus as claimed in any preceding claim incorporating or provided with heating means to heat at least one of said flows.

21. Ventilator apparatus as claimed in any preceding claim incorporating or provided with filter means to filter one of said flows.

22. Ventilator apparatus substantially as hereinbefore described with reference to any FIGURE of the accompanying drawings.

23. An installation in a building, whereit apparatus as claimed in any preceding claim is arranged to draw air into the building from a space between a roof of the building and a transparent covering.

24. A building-provided-with apparatus or an installation as claimed--in any preceding claim.