Title:
Vertical Door Fan Shutter
Kind Code:
A1


Abstract:
A fan shutter having one end attachable to an exhaust fan and the opposite inlet end having a pair of vertical doors that are biased to close when the fan is off and to open by the force of vacuum when the fan is on. The use of vertical doors prevents the accumulation of dust and dirt on the doors. The vertical doors pivot horizontally in a housing that may have any desired shape, including a tubular shape with a bell mouth. The tubular bell mouth shutter design further provides improved air flow characteristics and decreased stress on the exhaust fan, compared to conventional fan shutters.



Inventors:
Jenkins, Lesley Ray (Hanceville, AL, US)
Daniels, Waymon Neal (Danielsville, GA, US)
Application Number:
10/586431
Publication Date:
09/25/2008
Filing Date:
01/18/2005
Primary Class:
International Classes:
F24F13/00; F04D25/14; F24F7/007; F24F13/04; F24F13/08; F24F13/14
View Patent Images:
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Primary Examiner:
TOWNS, BRITTANY E
Attorney, Agent or Firm:
BUSH INTELLECTUAL PROPERTY LAW (Birmingham, AL, US)
Claims:
1. A fan shutter, comprising: a) a housing having one end attachable to a fan; b) said housing having an opposite end with one or more doors attached pivotably and centrally to said opposite end of said housing; and c) said one or more doors biased to close said opposite end of said housing.

2. The fan shutter of claim 1 wherein said one or more doors are attached to a center post by hinges at said opposite end of said housing.

3. The fan shutter of claim 1 wherein said one or more doors are biased to close by gravity by said opposite end of said housing being tilted from vertical.

4. The fan shutter of claim 1 wherein said one or more doors are biased to close by gravity by said housing being tilted downward while said opposite end of said housing remains vertical.

5. The fan shutter of claim 1 wherein said one or more doors are biased to close by the use of one or more counterweights.

6. The fan shutter of claim 1 wherein said one or more doors have hinges and are biased to close by the use of springs in said hinges.

7. The fan shutter of claim 1 wherein said housing is tubular.

8. The fan shutter of claim 7 wherein said opposite end of said housing has a bell mouth.

9. The fan shutter of claim 8 wherein said housing and said fan form a single unit.

10. The fan shutter of claim 1 wherein said opposite end of said housing has a bell mouth.

11. The fan shutter of claim 1 wherein said housing and said fan form a single unit.

12. A fan shutter, comprising: a) a housing having one end attachable to a fan and an opposite end having one or more doors attached pivotably to a centerpost; and b) said one or more doors being vertically oriented, biased to close said opposite end of said housing when said fan is not operating, and opening said opposite end of said housing when said fan is operating.

13. The fan shutter of claim 12 wherein said one or more doors are attached to said center post by hinges.

14. The fan shutter of claim 13 wherein said one or more doors are biased to close by gravity by said opposite end of said housing being tilted from vertical.

15. The fan shutter of claim 13 wherein said one or more doors are biased to close by gravity by said housing being tilted downward while said opposite end of said housing remains vertical.

16. The fan shutter of claim 13 wherein said one or more doors are biased to close by the use of one or more counterweights.

17. The fan shutter of claim 12 wherein said one or more doors have hinges and are biased to close by the use of springs in said hinges.

18. A fan shutter, comprising: a) a tubular housing having one end attachable to a fan and an opposite end having a bellmouth and one or more doors attached pivotably and centrally to said opposite end; and b) said one or more doors being vertically oriented, biased to close said opposite end of said housing when said fan is not operating, and opening said opposite end of said housing when said fan is operating.

19. The fan shutter of claim 18 wherein said one or more doors are biased to close by gravity by said opposite end of said housing being tilted from vertical.

20. The fan shutter of claim 18 wherein said one or more doors are biased to close by gravity by said housing being tilted downward while said opposite end of said housing remains vertical.

21. The fan shutter of claim 18 wherein said one or more doors are biased to close by the use of one or more counterweights.

22. The fan shutter of claim 18 wherein said one or more doors have hinges and are biased to close by the use of springs in said hinges.

23. The fan shutter of claim 18 wherein said housing and said fan form a single unit.

Description:

TECHNICAL FIELD

The present invention relates generally to the field of fan shutters and, more particularly, to fan shutters having a vertical orientation and which prevent air flow through a fan when the fan is off.

BACKGROUND ART

Buildings often have ventilation systems for the exchange of air between the building and the outside. These ventilation systems are usually complex and are connected to the air handling or heating and air conditioning system of the building. Other ventilation systems are less complex and are merely for exhausting stale air from the building, for introducing fresh air into the building, or for basic temperature regulation by exhausting hot or cold air from the building as necessary.

Various shutters, dampers, and closure panels for fans are known to regulate the exchange of air between the inside and outside of a building. For example, a series of horizontal louvers can be constructed to remain closed when the fan is off, but are pulled open by the airflow when the fan is on. A disadvantage of horizontal louvers is that dust builds up on the louvers, impeding their operation and airflow. Shutters constructed like a window shade roll down when the fan is off and roll up when the fan is on. A disadvantage of rolling shutters is that there are many mechanical and electrical parts that can fail or are difficult to maintain.

The general use of automatically opening and/or closing louvers, vents, and doors in connection with fans or other forced air systems is well known, including the use of the weight of the door alone, or the use of a counter weight to keep the door open or closed, or the use of string and pulley systems.

U.S. Pat. No. 6,533,656 to Hertel discloses a counterweighted cover for an air handling system duct. This is a horizontal closure to fit over an overhead or surface mounted duct vent. Forced air opens the cover, and when the forced air stops, the counterweight pivots the cover closed. U.S. Pat. No. 6,203,423 to Craw discloses a typical structure for a vertical damper flap. This is a gravity driven flap that is opened by forced air and closes by gravity when the forced air flow stops. U.S. Pat. No. 6,183,359 to Klein discloses a typical structure for a horizontal register flap. This is a gravity driven flap that is opened by forced air and closes by gravity when the forced air flow stops. U.S. Pat. No. 6,183,359 to Klein discloses a typical structure for a horizontal register flap. This is a gravity driven flap that is opened by forced air and closes by gravity when the forced air flow stops.

U.S. Pat. No. 6,061,968 to Zimmerman discloses a hinged door assembly comprising a weight to keep the door opened and a string/pulley/motor system to close the door. When it is desired to open the door, the motor unwinds the string and the weight, and the weight of the door opens the door. To close the door, the motor is reversed, winding the string. U.S. Pat. No. 5,921,862 to Ucciardi discloses a horizontally mounted door flap for use on the discharge opening of a fan. The forced air from the fan forces the door open and when the Forced air flow stops, the weight of the door causes the door to close by gravity. The door has a counterweight to make it easier for the door to remain open.

U.S. Pat. No. 5,567,114 to Wallace discloses a typical structure for a counterweighted door for closing a downwardly oriented fan outlet. This is a gravity driven flap that is opened by forced air and closes by the weight of the counterweight when the forced air flow stops. U.S. Pat. No. 5,195,927 to Raisanen discloses an intake vent for a barn. The described advantages of this vent include its ability to be mounted on either side of a wall and a counterweight for keeping the vent closed. U.S. Pat. No. 4,850,265 to Raisanen discloses a cupola mounted air vent for a building having a structure for baffling rain. This device also has counterweights for keeping the vent closed.

U.S. Pat. No. 4,047,328 to Kehl discloses a greenhouse structure including a cooling system comprising a horizontally pivotable vent flap held closed by a string/pulley and counterweight. The vent flap is hinged at its bottom to the greenhouse wall and opens from the top when the air pressure in the greenhouse is greater than outside. The string is attached to the top of the vent and is weighted to keep the vent closed. U.S. Pat. No. 3,631,790 to Olsen discloses an automatically closing louver. The louver has a horizontally mounted hinge and sits downstream of the air flow. The air flow opens the louver and when the air flow stops, the weight of the louver causes it to close. U.S. Pat. No. 3,363,531 to Kohlmeyer discloses a vent for an animal house comprising a closure flap operated by a string/pulley device. Pulling the string causes the flap to rotate open or closed.

U.S. Pat. No. 2,823,600 to Cole discloses a vent for use in an air conditioning system. The system comprises dampers that open and close depending on whether a fan is on or off. When the fan is on, the pull of the air opens the dampers. U.S. Pat. No. 2,502,736 to Marcoe discloses a horizontally hinged intake vent with a counterweight damper plate. Air pressure causes the vent to open and when the air pressure equilibrates, the counterweight causes the vent to close. U.S. Pat. No. 218,596 to Taber discloses a horizontally hinged damper that opens inwardly to a duct when the air pressure within the duct is lower than the air pressure outside of the duct, and is for use in a stovepipe. A counterweight closes the vent when the air pressure equilibrates.

Animal houses, such as chicken houses must have exhaust ventilation. Large fans typically are mounted on one end of the chicken house to pull air out of the chicken house. When the fans are on, there must be as unimpeded an air flow through the fan as possible to allow for both adequate ventilation and fan efficiency. When the fans are off, it is preferable to prevent air from escaping from the chicken house and/or air entering the chicken house through the fan box. This is especially true in the summer and winter to prevent the chicken houses from becoming too hot (summer) or too cold (winter) and to prevent excessive cooling or heating costs. Fan shutters can be valuable in lowering heating and cooling costs and in providing a better environment for the inhabitants of the building.

Notwithstanding the use of known ventilation systems, there is need for a mechanically simple and relatively low cost fan shutter that does not require frequent maintenance and/or repair.

DISCLOSURE OF THE INVENTION

The present invention has a housing that fits over a fan on the interior of a building. The back of the housing faces the fan. The front or inlet of the housing has two vertical doors that swing horizontally and that open and close when the fan is turned on and off, respectively. The housing uses one or more mechanisms to keep the doors shut when the fan is off. In a first embodiment the top of the housing extends farther out than the bottom of the housing so that the doors are not quite vertical, and the tops of the doors are biased outward relative to the fan. Thus, gravity makes the doors swing shut. When the fan is on, the vacuum caused by the fan is sufficient to open the doors. In a second embodiment a counter weight is attached by a wire to each door. The counter weight biases the doors toward a closed position. In a third embodiment a spring is built into the hinge of each door to bias the doors toward a closed position. A combination of these mechanisms can be used to ensure the doors remain closed when the fan is off. The housing can have a rectangular or triangular shape. Alternatively, the housing can have a tubular shape with a bell mouth on the inlet side.

An advantage of the present invention is a fan shutter that is simple in construction, durable, and easy to construct.

Another advantage is a fan shutter that requires little maintenance.

Another advantage is a fan shutter that is inexpensive.

Another advantage is a fan shutter that prevents air flow across the fan when the fan is off.

Another advantage is a fan shutter that improves the performance and efficiency of an air moving device such as, for example, a fan.

Another advantage is a fan shutter that improves breeding productivity in a poultry house.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a front view of the fan shutter of the present invention wherein the doors are mounted slightly less than vertical, using gravity for door closure.

FIG. 2 is a side view of the fan shutter of FIG. 1 showing the front end of the housing tilting downward.

FIG. 3 is a side view of an embodiment in which the entire housing tilts downward.

FIG. 4 is a side view of the fan shutter wherein the doors are mounted vertical, using springs or counterweights for door closure.

FIG. 5 is a front view of the fan shutter with a tubular housing having a bell mouth on the intake side of the housing, the doors being in a closed position.

FIG. 6 shows the fan shutter of FIG. 5 with doors in an open position.

BEST MODE FOR CARRYING OUT THE INVENTION

While the following description details the preferred embodiments of the present invention, it is to be understood that the invention is not limited in its application to the details of construction and arrangement of the parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced in various ways.

FIG. 1 shows a front view of the fan shutter 10 of the present invention. Fan shutter 10 has a housing 11 that covers exhaust fan 24 and that supports doors 17. Housing 11 has a top 12, a bottom 13 and sides 14. The front end (inlet side) 25 is, preferably, triangular in shape with a center post 16. Doors 17 are mounted pivotally to center post 16 with hinges 18. Doors 17 are biased to close the open front end of housing 11 when the fan is off. Doors 17 are biased in a closed position, preferably, by the force of gravity. This is accomplished by mounting housing 11 vertically, but having the front end 25 tilt downward slightly from vertical about 1 to 20 degrees. Alternatively, the housing can be mounted tilting downward slightly from vertical about 1 to 20 degrees, while the front end 15 of the housing remains vertical. These features are shown in more detail in FIGS. 2 and 3. Because the doors are mounted in a vertical orientation and rotate horizontally, they will close the openings of the front end of shutter 11 when the fan is off. Doors 17 contact front edges 15 of housing 11 upon complete closure of the front end of housing 11. Front edges 15 prevent doors 17 from swinging outside housing 11. Back end 26 of housing 11 is attached adjacent to Fan 24 using tabs or flanges 19. Doors 17 can also be biased using counter weights 21 with cables 22, or with springs in the hinges 18. Gravity, counterweights, or springs can be used separately or in combinations to bias door 17 in a closed position. When exhaust fan 24 is turned on it creates sufficient vacuum to open the doors, even though the doors are biased towards a closed position. The use of vertical doors instead of horizontal louvers provides improved air flow and less stress on the fan. In addition, vertical doors provide less surface openings for the accumulation of dirt, compared to horizontal louvers.

FIG. 2 shows a side view of the fan shutter 10 shown in FIG. 1. The top 12 of housing 11 extends further from the wall 23 than the bottom 13. Thus, front end 12 and center post 16 tilt downward, biasing the doors 17 to close by the force of gravity when fan 24 is not operating. FIG. 3 shows an alternate construction of housing 11, wherein the entire housing 11 tilts downward but front end 25 remains vertical. Doors 17 are also biased in the closed position by the force of gravity with this construction.

FIG. 4 shows a side view of the fan shutter 10 of FIG. 1, except that neither the housing 11 or front end 25 tilt downward. The entire housing is mounted precisely vertical. In this embodiment doors 17 are not biased to close by the force of gravity. The doors can be biased with counterweights 21 or springs in hinges 18 or both.

FIG. 5 illustrates an alternate embodiment of the present invention wherein the housing is round. Fan shutter 30 has a tubular housing 31. The back end 36 of housing 31 fits over wall 35 in front exhaust fan 38. Front end 37 (inlet) of housing 31 has a bell mouth 32, and two vertical doors 33 which are hinged directly to front end 37 of housing 31 at hinge points 34. The bell mouth 32 and tubular shaped housing 31 allow air to flow more smoothly and evenly without turbulence compared to rectangular units, improving the air flow and efficiency of exhaust fan 38. The front end 37 of the housing 31 can be tilted as described in FIGS. 1-4, so that doors 31 are biased in a closed position by gravity. Accordingly, the doors 33 will remain shut when exhaust fan 38 is off. When exhaust fan 38 is on, the vacuum created by exhaust fan 38 will open doors 33. Hinging of doors 33 at hinge points 34 can be accomplished by pins or inserts on doors 33 extending into housing 31. Thus, vertical doors 33 will pivot horizontally at hinge points 34. Doors 33 can also be biased in a closed position by the use of springs at the hinge points 34, or by counterweights, as described in FIGS. 1-4. FIG. 6 shows the fan shutter 30 of FIG. 5 with doors 33 in an open position. A one piece, unified, damper fan combination can be constructed by having housing 31 and fan system 38 form a single unit.

The foregoing description has been limited to specific embodiments of this invention. It will be apparent, however, that variations and modifications may be made by those skilled in the art to the disclosed embodiments of the invention, with the attainment of some or all of its advantages and without departing from the spirit and scope of the present invention. For example, the fan shutter can have curved edges and corners for safety. Other pivot joints known in the art besides hinges can be used on the doors. In addition to the front edges of the housing, other door stop mechanisms known in the art can be used to prevent the doors from swinging outside the housing and to insure that the doors seal the front end of the housing. A spring device can be added in the center of the doors and counter levered over so that when the doors are open, while the fan is operating, they will not have any pressure against them. Any type of suitable material can be used for the cable to connect the counterweight to the door, including string, twine, cable, chain, rope, and the like. The fan shutter can be built to any size to accommodate any size fan, and can be incorporated into the fan housing to form a single unitary housing for the fan, fan motor, shutter, and related parts. The shutter housing can be round, elliptical, square, or otherwise, and the bell mouth can be used with any shaped housing. The front end of the housing can be flat (coplanar with the fan) or round, instead of triangular. The front end of the housing can have one or a plurality of doors. The fan shutter of the present invention can be made from any suitable materials such as, for example, plastic, metal, wood, ceramics, fibers, glasses or a combination thereof.

It will be understood that various changes in the details, materials, and arrangements of the parts which have been described and illustrated above in order to explain the nature of this invention may be made by those skilled in the art without departing from the principle and scope of the invention as recited in the following claims.