US3366030A

US3366030A - Roof mounted ventilator

Info

Publication number: US3366030A
Application number: US447186A
Authority: US
Inventors: Lambie Howard Russell; Raymond A F Burtenshaw
Original assignee: Colt Ventilation and Heating Ltd
Current assignee: Colt Ventilation and Heating Ltd
Priority date: 1964-04-13
Filing date: 1965-04-12
Publication date: 1968-01-30
Anticipated expiration: 1985-01-30
Also published as: BE662451A; GB1061187A; DE1918397U; NL6504729A; DE1604145B1

Description

Jan. 30, 1968 i H. R. LAMBIE ETAL 3,366,030

ROOF MOUNTED VENTILATOR Filed April 12, 1965 2 sheets-.sheet 1 INvENW-oa MMA Russe win( A4 ATTQRNEYS Jan. 30, 1968 H. R. I AMBlE ETAL l ROOF1 MOUNTED VENTILATOR Filed April 12, 1965 2 Sheets-Sheet 2 United States Patent Ciiice liiidd Patented Jian. 310, i968 3,366,ll3tl FLGE MUUNTED VENTILATE Howard Russell Lambie, Hayiing island, and Raymond A. F. Burtenslraw, Havant, England, assignors to Colt Ventilation and Heating Limited, Surbiton, Engiand, a British company liiiled Apr. 12, i965, Ser. No. 447,186 Claims priority, application Great Britain, Apr. 13, 1964, 15,226/64 2 Claims. (Cl. 98--43) This invention relates to ventilators and is concerned with powered, upward discharge ventilators for use without a weathering cowl. ln such a ventilator a self-weathering, non-return shutter assemblage is employed to close the exit from the extraction ian duct when the fan is not operating and thereby prevent weather entry and down draught, as well as conserving the heat in the building.

According to the present invention there is provided a powered, upward discharge ventilator having a self weathering non-return shutter assemblage for closing the exit from the extraction fan duct of the ventilator when the ventilator is not operating, the shutter assemblage being provided with a surrounding tubular windshield having an upper, open end and a lower end which is blocked or substantially wholly blocked by the shutter assemblage whereby, in use of the ventilator, entrainment of air into the air stream discharging from the shutter assemblage, through the tubular shield, from outside the shield, through the lower end of the shield, is wholly or substantially wholly prevented.

It will be understood that the shutter assemblage blocks the lower end of the tubular shield in the sense that it occupies the whole or substantially the 'whole ot the opening in its lower end whereby the lower end of the shield is open only to the air stream emerging through the non-return shutters and is closed when the non-return shutters are closed.

Entrainment of air through the lower end of the windshield involves the unnecessary acceleration of extraneous air, with a consequent loss of eiiciency of the ventilator. By substantially or wholly preventing such entrainrnent, it has been found that the emciency of the ventilator may be increased to a significant extent. Thus, by this means, a useful contribution may be made to increasing the capacity of the ventilator or to reducing the fan speed rwhilst maintaining the same rate of extraction of air from the building and, in this way, reducing the noise level of the ventilator.

As will readily be appreciated, since the shutter assemblage blocks the lower end of the shield, the effect is to form a large open-topped receptacle for rain water when the extraction fan is not operating and the nonreturn shutters are closed. At the expense of some entrainment therefore, openings must be left for the drainage of water from inside the shield on to the roof around the outside of the non-return shutter assemblage.

The means provided to drain ott this water need not, however, be at the expense of any significant entrainment of air into the windshield and .consequent loss of efciency provided that the openings are kept small.

According to a feature of the present invention, a guttering may be incorporated at the bottom of the tubular shield, the guttering surrounding the non-return shutters at a level below the plane of the shutter openings and communicating with one or more localised drain openings for draining water to the outside of the windshield at right angles.

The tubular shield may be of constant cross-sectional rea or it may be smoothly and upwardly convergent at least over an exit portion thereof towards its upper end. Preferably however, the windshield is smoothly and upwardly divergent at least over an exit portion thereof towards its upper end, so as to reduce the velocity of discharge ot the air and thereby secure a further improvement in eciency of ex action for the ventilator.

A specific embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings in which:

FlG. 1 is a side elevation of a powered upward discharge ventilator according to the present invention partly broken away and partly in cross-section to show certain details of construction, and

FIG. 2 is a plan view of the Ventilator shown in FIG. l.

Referring to the drawings, the ventilator comprises a self weathering non-return shutter assemblage generally indicated at 1li (see FG. 2). comprising a rectangular base plate 11 carrying a rectangular sectioned extract fan duct portion 12 which opens through the base plate 11 and extends upwardly therefrom. The self `weathering nonreturn shutters 13 close this duct portion, the plane of the shutter openings corresponding with that of the upper end of the duct portion 12 and lying above the level of the base plate 11. The base plate 11 has a surrounding, down-turned flange 1d at its outer periphery. A tubular `windshield 15, which is of corresponding rectangular cross-section to the base plate 1i at its lower end, is carried by the down-turned ilange 11's of the base plate so as to extend upwardly above the level of the top of the shutters 13 when the shutters are in their fully open position (as shown chain dotted in FIG. l). The base plate 11 fully blocks the lower end of the tubular windshield. Small localised windows or drain openings 1S are provided in the lower corners of each of the four walls of the windshield at the level of the upper surface of the base plate 11.

The duct portion 12, a lower portion of the tubular wall of the windshield 12 adjacent its lower end. and the base plate 11 together form a rectangular sectioned guttering 2@ surrounding the shutter assemblage at the bottom of the windshield 15 at a level below the level of the plane of the shutter openings and this guttering collects water entering the windsheld when the shutters are closed, the water draining through the openings 18 to the outside of the windshield on to the surrounding roof. The drain openings 1d are conveniently formed by cutouts extending from the lower edge of the windshield 15.

The windshield has a lower tubular portion of uniform cross-section and an upper, exit portion which is smoothly and upwardly divergent, the walls of the exit portion being correspondingly r'lared outwardly. rlhe velocity of disharge of the air stream is accordingly slowed ia the exit portion. Alternatively, the windshield may be of constant cross-sectional area or again it may be smoothly and upwardly convergent over at least an exit portion thereof towards its upper end whereby the velocity of discharge of the airstream is increased to carry it up- 3 wardly well clear of the roof surface in special circumstances.

The self weathering shutter assemblage according to the present example is constructed as described in our co-pending application No. 413,715. The non-return shutters i3 are automatic in that they are opened by the forced draught of the fan and close under the action of gravity assisted by torsion bar springs when the fan is stopped. The windshield 1S acts to shelter the shutters l5 from movement by the wind both when they are open and when they are closed.

Specifically, as may be seen by reference to FIG. 2, four hinged shutters 13 are employed. Each shutter is hinged on a hinge rod 13a radiating from the center of the non-return shutter assemblage. A separate hinge bracket 13b is provided to support the outer end of each hinge rod i351, the bracket having an angled part overlying the shutter on the hinge rod, the angled part carry- Zing a rubber gromrnet plug 22 which acts as a top lirniting the `opening of the shutter to an angle or" about .50 in the present example as shown in chain dotted outline in FIG. 1.

The shutter assemblage is hingeably mounted as 'at 24 on a pedestal base generally indicated at 25. The pedestal base houses the fan-motor unit 2S of the ventilator. The pedestal base comprises an upper rectangular end plate 30 corresponding substantially in shape and dimensions with the base plate l1 of the shutter assemblage and which tits within the down turned flange 14 carrying the windshield l5, an intermediate duct portion 31 opening therethrough, the intermediate duct portion 3i Corresponding in cross-sectional shape and dimensions with the duct portion 12 of the shutter assemblage 1t) and forming the fan-motor unit housing, and a lower end plate 32 which is dashed (by means not shown) to the roof 33. The duct portion 31 of the pedestal base opens through the upper and lower end plates 30, 32 of the base and joins with the duct portion l2 of the shutter assemblage to form the extraction duct of the ventilator.

The shutter assemblage itl may be swung back on its hinge axis 2d to expose the fan-motor unit 23 for servicing. Bolts 33 entered through open ended slots in the flange 14 and the lower edge of the windshield carry wing nuts 3d to secure the shutter assemblage lt) against opening when not desired.

The drain openings 18 lie parallel to the direction of the air stream emerging through the non-return shutters 15 when the ventilator is operating. They are therefore, unfavourably disposed for entrainrnent through them of extraneous air. The openings 1S are nevertheless kept small whereby no significant loss due to entraiument of extraneous air can take p-lace.

instead of forming the openings 18 in the tubular wall of the windshield l5 they may be formed in the base plate lll. For example, the four corners of the base plate it may have drain openings, these openings coinciding with openings in the upper end plate 30 O the pedestal base. The drain openings last described are kept small whereby no signiiicant loss occurs due to entrainment of extraneous air through the openings.

When the ventilator is operating, the shutters 113 float on the air stream discharged by the fan and the velocity of disharge of air through the windshield is suhcient to blow away rain and prevent it entering through the shutter openings into the building.

When the fan is stopped the shutters close automatically. in their closed position each shutter 13 is inclined so as to drain water towards and into the guttering 2li where it is collected and drained on to the roof through the drain openings i8. Gutters ll are also provided, as part of the non-return shutter assemblage l), crossing the upper open end of the duct portion l2 to collect water draining ofi the shutters i3 over the duct portion l2, into the guttering 2d.

The smoothly and upwardly divergent exit portion of the windshield l5 acts on the discharging airstream to reduce the velocity of discharge of the air thereby reducing the kinetic energy dissipated in the airstrearn without iucurring substantial losses due to creating turbulence in the airstream and the pertorrnance of the ventilator is thus improved. This effect is achieved despite the necessity of providing a gap between the lower end of the windshield and the duct portion l2, vthe upper end of which deiines the exit of the extraction fan duct, to allow the drainage of water entering the upper end oi the windshield 15 downwardly outside the direction portion l?, between it and the windshield and into the glittering Zd. The shutters 13, since they are inclined with respect to the airstrearn emerging from the extraction fan duct when open and particularly when they are engaged against the shutter stops 22, act to deflect the airstream in part towards the inner surface of the windshield whereby discharging air is assisted in bridging the drainage and attaching itself to the inner wall surface of the windshield. The swirling motion imparted to the air in the fan impeller also assists in this respect.

We claim:

A powered, direct upward discharge ventilator for a buildino comprising an extracion fan duct having an upper, upwardly directed open end and a lower open end, said extraction fan duct leading extracted air from the building entering the lower open end of the duct from inside the building outside the buiding through the upper upwardly directed open end of the duct, an extraction fan, first mounting means mounting said extraction fan in said extraction tan duct, second mounting means, on said extraction fan duct for mounting the duct to the building, non-return shutters mounted on the upper upwardly directed open end of the extraction fan duct and arranged when open for the direct upward discharge of the extracted air through the upper upwardly directed open end of the extraction fan duct, and, when closed, to weather the upper upwardly directed open end of the extraction lan duct and to prevent downdraught and the loss of heat from inside the buildig, a tubular windshield for said shutters, said windshield having a lower end third mounting means on said duct and outside said duct below the level of the upper upwardly directed open end of said duct and mounting said tubular windshield to the extraction fan duct with the lower end of the windshield below the level of the upper upwardly directed open end of said extraction fan duct, the lower edge of the windshield surrounding the upper upwardly directed open end of the extraction tan duct with clearance and deiining therewith an annular gap, the windshield extending upwardly above the upper upwardly directed open end of the extraction fan duct to an upper upwardly directed open end through which the upper upwardiy directed open end of the extraction fan duct is exposed to direct weather entry, the improvement consisting in that the third mounting means comprises a peripheral outwardly directed mount` ing llange on the exterior of extraction fan duct which ange at least substantially wholly blocks said annular gap se as to prevent the entrainment of at least any substantial quantity of air from outside the building through the lower end of the windshield into the airstream discharging through the upper, upwardly directed end of the extraction fan duct, said extraction fan duct cornprising a base portion having a lower open end defining the lower open end of the duct, said base portion having an outwardly directed ange at its upper end, and an open upper portion defining the upwardly directed open end of the duct, said upper portion having an outwardly directed iiange at its lower end overlying said first said flange at the upper end of the base portion of the duct, the outwardly directed Piange on the upper portion of the duct constituting said peripheral mounting liange and carrying said windshield, and means is provided hingeably connecting said flanges.

2. A powered upward discharge ventilator as claimed in claim 1, wherein the said windshield being smoothly and upwardly divergent at least over an exit portion thereof towards its upper end, so as to reduce the velocity of discharge of the extracted air from the upper end of the Windshield.

References Cited UNITED STATES PATENTS 6 2,684,621 7/1954 Cook 98--116 X 2,783,702 3/1957 ODay 98--111 X 3,012,495 12/ 1961 Miller 98-119 X 3,181,451 5/1965 Hess 98-119 X FOREIGN PATENTS 129,416 8/ 1932 Germany. 1 14,499 4/ 1918 Great Britain.

ROBERT A. OLEARY, Primary Examiner. M. A. ANTONA-KAS, Assistant Examiner.

Claims

1. A POWERED, DIRECT UPWARD DISCHARGE VENTILATOR FOR A BUILDING COMPRISING AND EXTRACTION FAN DUCT HAVING AN UPPER, UPWARDLY DIRECTED OPEN END AND A LOWER OPEN END, SAID EXTRACTION FAN DUCT LEADING EXTRACTED AIR FROM THE BUILDING ENTERING THE LOWER OPEN END OF THE DUCT FROM INSIDE THE BUILDING OUTSIDE THE BUILDING THROUGH THE UPPER UPWARDLY DIRECTED OPEN END OF THE DUCT, AND EXTRACTION FAN, FIRST MOUNTING MEANS MOUNTING SAID EXTRACTION FAN IN SAID EXTRACTION FAN DUCT, SECOND MOUNTING MEANS, ON SAID EXTRACTION FAN DUCT FOR MOUNTING THE DUCT TO THE BUILDING, NON-RETURN SHUTTERS MOUNTED ON THE UPPER UPWARDLY DIRECTED OPEN END OF THE EXTRACTION FAN DUCT AND ARRANGED WHEN OPEN FOR THE DIRECT UPWARD DISCHARGE OF THE EXTRACTED AIR THROUGH THE UPPER UPWARDLY DIRECTED OPEN END OF THE EXTRACTION FAN DUCT, AND, WHEN CLOSED, TO WEATHER THE UPPER UPWARDLY DIRECTED OPEN END OF THE EXTRACTION FAN DUCT AND TO PREVENT DOWNDRAUGHT AND THE LOS OF HEAT FROM INSIDE THE BUILDING, A TUBULAR WINDSHIELD FOR SAID SHUTTERS, SAID WINDSHIELD HAVING A LOWER END THRID MOUNTING MEANS ON SAID DUCT AND OUTSIDE SAID DUCT BELOW THE LEVEL OF THE UPPER UPWARDLY DIRECTED OPEN END OF SAID DUCT AND MOUTING SAID TUBULAR WINDSHIELD TO THE EXTRACTION FAN DUCT WITH THE LOWER END OF THE WINDSHIELD BELOW THE LEVEL TO THE UPPER UPWARDLY DIRECTED OPEN END OF SAID EXTRACTION FAN DUCT, THE LOWER EDGE OF THE WINDSHIELD SURROUNDING THE UPPER UPWARDLY DIRECTED OPEN END OF THE EXTRACTION FAN DUCT WITH CLEARANCE AND DEFINING THEREWITH AN ANNULAR GAP, THE WINDSHIELD EXTENDING UPWARDLY ABOVE THE UPPER UPWARDLY DIRECTED OPEN END OF THE EXTRACTION FAN DUCT TO AN UPPER UPWARDLY DIRECTED OPEN END THROUGH WHICH THE UPPER UPWARDLY DIRECTED OPEN END OF THE EXTRACTION FAN DUCT IS EXPOSED TO DIRECT WEATHER ENTRY, THE IMPROVEMENT CONSISTING IN THAT THE THIRD MOUNTING MEANS COMPRISES A PERIPHERAL OUTWARDLY DIRECTED MOUNTING FLANGE ON THE EXTERIOR OF EXTRACTION FAN DUCT WHICH FLANGE AT LEAST SUBSTANTIALLY WHOLLY BLOCKS SAID ANNULAR GAP SO AS TO PREVENT THE ENTRAINMENT OF AT LEAST ANY SUBSTANTIAL QUANTITY OF AIR FROM OUTSIDE THE BUILDING THROUGH THE LOWER END OF THE WINDSHIELD INTO THE AIRSTREAM DISCHARGING THROUGH THE UPPER, UPWARDLY DIRECTED END OF THE EXTRACTION FAN DUCT, SAID EXTRACTION FAND DUCT COMPRISING A BASE PORTION HAVING A LOWER OPEN END DEFINING THE LOWER OPEN END OF THE DUCT, SAID BASE PORTION HAVING AN OUTWARDLY DIRECTED FLANGE AT ITS UPPER END, AND AN OPEN UPPER PORTION DEFINING THE UPWARDLY DIRECTED OPEN END OF THE DUCT, SAID UPPER PORTION HAVING AN OUTWARDLY DIRECTED FLANGE AT ITS LOWER END OVERLYING SAID FIRST SAID FLANGE AT THE UPPER END OF THE BASE PORTION OF THE DUCT, THE OUTWARDLY DIRECTED FLANGE ON THE UPPER PORTION OF THE DUCT CONSTITUTING SAID PERIPHERAL MOUNTING FLANGE AND CARRYING SAID WINDSHIELD, AND MEANS IS PROVIDED HINGEABLY CONNECTING SAID FLANGES.