HVAC damper

• US 6,435,211 B2
• Filed: 05/29/2001
• Issued: 08/20/2002
• Est. Priority Date: 07/13/1999
• Status: Expired due to Fees

• Current Assignee: Garrick S. Stone, William L. Stone
• Original Assignee: Garrick S. Stone, William L. Stone
• Inventors: Stone, Garrick S., Stone, William L.
• Primary Examiner(s): Buiz, Michael Powell
• Assistant Examiner(s): Krishnamurthy, Ramesh
• Application Number:
  US09/867,116
• Publication Number:
  US 20010027814A1
• Time in Patent Office: 448 Days
• Field of Search: 137/73, 137/74, 137/75, 137/77, 137/601.01, 137/601.12, 137/601.14, 137/601.15, 192/56.55, 192/56.56, 251/67, 251/212, 251/250, 251/901, 454/333, 454/369
• US Class Current: 137/601.12
• CPC Class Codes: F16K 17/383 the valve comprising fusible, softening or meltable elements, e.g. used as link, blocking element, seal, closure plug F16K17/386 takes precedence
• CPC Class Codes: F16K 51/02 specially adapted for high-vacuum installations
• CPC Class Codes: F24F 13/10 movable, e.g. dampers
• CPC Class Codes: F24F 2013/1446 with gearings
• CPC Class Codes: Y10T 137/87491 Mechanical movement between actuator and non-rotary valve

Abstract

A fail-safe HVAC damper apparatus comprises a duct channel with a closure comprising one or more quadri-panel hinged elements, each with four panels connected by four parallel hinge pins. A gear shaft with a toothed gear is controllably rotated to linearly drive a spring-biased plate to move one of the hinge pins of each quadri-panel element between an open and a closed position. A damper may use blades of different sizes and be driven to begin an opening and/or closing action sequentially and/or very gradually. A drive motor may be activated to open or close the closure, e.g. by a smoke detector or other controller. Melting of a fuse in the duct channel serves to disengage a gear from a gear shaft, enabling a spring mounted plate to move the hinged elements to a default closed (or alternative open) safety position. Various gear shaft and gear structures are shown.

Claims

1. A damper apparatus for controlling gas flow in a duct, comprising:

inner walls defining a gas-confining inner channel between inlet and outlet openings;

a closure operable between an open position and a closed position, said closure comprising;

a blade formed of first, second, third and fourth elongate panels, each panel having opposed hinged edges;

four parallel hinge pins connecting hinge edges of the panels in a quadrilateral wherein each panel is rotatable relative to adjacent connected panels;

a stationary hingepin with opposed ends, said stationary hingepin connecting first hinged edges of said first panel and said second panel, said stationary hingepin having its ends mounted in opposing inner walls;

a first floating hingepin connecting second hinged edge of said first panel and first hinged edge of said third panel;

a second floating hingepin connecting second hinged edge of said second panel and first hinged edge of said fourth panel;

a drive hingepin connecting second hinged edges of said third panel and said fourth panel;

whereby said panels form a quadrilateral with four exterior angles between adjacent panels; and

drive means communicating with said drive hingepin for driving said drive hingepin to move said closure between said open position and said closed position;

wherein in said closed position, the exterior angle between said third and fourth panels is less than 180 degrees.

2. A damper apparatus of claim 1 wherein in said closed position said exterior angle between said third and fourth panels is between about 165 and 180 degrees.

3. A damper apparatus of claim 1 wherein in said closed position said exterior angle between said third and fourth panels is between about 170 degrees and about 176 degrees.

4. A damper apparatus of claim 1 wherein the distance between said stationary hingepin and a floating hingepin exceeds the distance between said drive hingepin and a floating hingepin.

5. A damper apparatus of claim 1, further comprising a biasing means to bias said closure to one of said open position and said closed position.

6. A damper apparatus of claim 1, wherein said apparatus comprises at least two blades of substantially identical dimensions.

7. A damper apparatus of claim 1, wherein said apparatus comprises at least two blades with space therebetween, further comprising at least one blade seal attached to one of said blades for closing and sealing said space when said closure is in said closed position.

8. A damper apparatus of claim 7, wherein said blade seal comprises:

a sealing member attached to one panel of a first blade to extend to and compress against a panel of a second blade, generally coextensive with a floating hinge pin thereof.

9. A damper apparatus of claim 8, wherein movement of said closure to said closed position having an outer angle between said third and fourth panels of less than 180 degrees compresses said sealing member against said second blade.

10. A damper apparatus of claim 8, wherein said sealing member is formed of a thin flexible material bent along a longitudinal axis in a direction whereby said seal compresses and seals against an opposite panel of an adjacent blade in said closed position.

11. A damper apparatus of claim 10, wherein said blade seal comprises spring metal.

12. A damper apparatus of claim 7, said blade seal comprising:

a first blade seal fixed on a panel of a first blade along a first floating hingepin thereof; and

a second blade seal fixed on a panel of an adjacent blade along a second floating hingepin thereof;

wherein in said closed position said first blade seal is coextensive with a portion of said first floating hingepin to seal an equivalent coextensive portion of said second blade; and

wherein in said closed position said second blade seal is coextensive with the remaining portion of said first floating hingepin to seal the remaining portion of said first blade.

13. A damper apparatus of claim 7, wherein each said blade seal of a blade compressively covers an adjacent floating hingepin of the same blade when in said open position.

14. A damper apparatus of claim 1, wherein said drive means comprises:

a motor;

a motor shaft drivable by said motor between angular limits;

a gear shaft attached to said motor shaft for rotation thereby;

a gear hub mounted on said gear shaft for rotation thereby;

a gear mounted on said gear hub for rotation thereby;

a movable slide assembly with a toothed rack, said slide assembly engaging said drive hingepin to move it generally linearly; and

wherein said gear engages said toothed rack to move said movable slide assembly.

15. A damper apparatus of claim 14, further comprising a disengagement apparatus between said motor shaft and said gear for disengagement therebetween.

16. A damper apparatus of claim 15, wherein said disengagement apparatus comprises:

a gear hub attached coaxially to said gear;

a gear shaft passing through said gear hub and coaxial therewith; and

a rotatably movable cog connecting said gear shaft to said gear hub for engagement therebetween, said cog movable to a disengaging position whereby gear rotates freely on said gear shaft.

17. A damper apparatus of claim 1 wherein said drive hingepin has at least one end movable in a slot in one of said inner walls by said drive means, and further comprising a slot seal formed of a flexible material configured to be joined to said inner wall and overcover said slot, said slot seal having holes therethrough coextensive with slot end portions and a slit joining said holes, wherein said slot seal seals said slot.

18. A damper apparatus for controlling gas flow in a duct, comprising:

a duct having inlet and outlet openings;

inner walls defining a gas-confining inner channel between said inlet and outlet openings;

a multi-blade closure operable between an open position and a closed position, each said blade comprising;

four panels hinged with a stationary hingepin having its ends mounted at fixed positions in opposing inner walls, a linearly movable drive hingepin and two floating hingepins to form a quadrilateral; and

linear slots in an inner wall for passage therethrough of the drive hingepins of said blades;

wherein when in a closed position, said blades have different closing spans ranging from a largest span to a smaller span, said apparatus further comprising;

drive means for moving the drive hingepin of said blades between said open position and said closed position by substantially linear movement, said drive means including a slide plate communicating with said drive hingepins;

wherein said slide plate is a progressive action slide plate for moving said drive hingepins sequentially between an open position and a closed position to produce an exponential opening flow curve having reduced flowrate during first portion of plate movement, and an exponential closing flow curve having less flowrate reduction during first portion of plate movement, said flow curves being compared to a damper with blades having uniform closing spans.

19. A damper apparatus of claim 18, wherein said stationary hingepins lie in a plane perpendicular to the general direction of airflow, the drive hingepin of the largest blade has an end engaging a fixed location on said slide plate, and an end of a drive hingepin of a smaller blade is movable in a linear slot in said slide plate, said slide plate slot having ends corresponding to the open position and the closed position of said smaller blade.

20. A damper apparatus of claim 18, further comprising a slot seal formed of a flexible material joined to said inner wall and overcover said inner wall slot, said slot seal providing resistance to movement of said drive hingepin therethrough, said slot seal having holes therethrough coextensive with slot end portions and a slit joining said holes, wherein said slot seal reduces air leakage through said inner wall slot.

21. A damper apparatus of claim 18, wherein said drive means comprises:

a slide plate positioned in an inner wall;

linear slots in said inner wall for passage therethrough of the drive hingepins of said blades to communicate with said slide plate;

wherein said slide plate is a progressive action slide plate for moving said drive hingepins sequentially between an open position and a closed position to produce an exponential opening flow curve having reduced flowrate during first portion of plate movement, and an exponential closing flow curve having less flowrate reduction during first portion of plate movement, said flow curves being compared to a damper with blades having uniform closing spans.

22. A damper apparatus for controlling gas flow in a a duct, comprising:

a duct having inlet and outlet openings;

inner walls defining a gas-confining inner channel between said inlet and outlet openings;

inner walls defining a gas-confining inner channel between said inlet and outlet openings;

a multi-blade closure operable between an open position and a closed position, each said blade comprising;

four panels hinged with a stationary hingepin having its ends mounted at fixed positions in opposing inner walls, a linearly movable drive hingepin, and two floating hingepins to form a quadrilateral, wherein, when in a closed position, said blades have different closing spans ranging from a largest span to a smaller span, said apparatus further comprising;

linear slots in an inner wall for passage therethrough of the drive hingepin of said blades; and

drive means for moving the drive hingepins of said blades between said open position and said closed position by substantially linear movement, said drive means including a slide plate communicating with said drive hingepins;

wherein said stationary hingepins lie in a plane perpendicular to the general direction of airflow, the drive hingepin of said largest blade has an end engaging a fixed location on said slide plate, and

wherein an end of a drive hingepin of said smaller blade is movable in a linear slot in said slide plate, said slide plate slot having ends corresponding to said open position and said closed position of said smaller blade; and

wherein said slide plate is a progressive action slide plate for moving said drive hingepins sequentially between an open position and a closed position to produce an exponential opening flow curve having enhanced flowrate during first portion of plate movement, and an exponential closing flow curve having enhanced flowrate during first portion of plate movement, and an exponential closing flow curve having enhanced flowrate reduction during first portion of plate movement, said flow curves being compared to a damper with blades having equal closing spans.

23. A damper apparatus of claim 22, further comprising a slot seal formed of a flexible material joined to said slide plate to overcover said slide plate slot, said slot seal providing resistance to movement of said drive hingepin therethrough greater than resistance to movement at said inner wall slot, said slot seal having holes therethrough coextensive with slot end portions and a slit joining said holes.

24. A damper apparatus for controlling gas flow in a duct, comprising:

inner walls defining a gas-confining inner channel between inlet and outlet openings;

a closure within said inner walls;

motor means;

motor shaft attached to said motor means for rotation thereby;

drive means connecting said motor shaft to said closure for operating said closure between an open position and a closed position, said drive means comprising;

rotatable means operating to open and close said closure;

a disengagement apparatus for engaging and disengaging said motor shaft from said rotatable means, said disengagement apparatus comprising;

a gear shaft attached to said motor shaft for rotation therewith about a central axis;

a hub coaxially mounted on said gear shaft for controllable one of rotation therewith and rotation thereabout, said rotatable means mounted on said hub.

25. A damper apparatus of claim 24, wherein said rotatable means comprises a gear.

26. A damper apparatus of claim 24, wherein said disengagement apparatus further comprises:

an opening in said gear shaft;

an opening in said hub;

a cog rotatable within said gear shaft opening and extendable into said hub opening for engagement therewith;

a spring-biased key movable between an engagement position and a disengagement position within said gear shaft;

wherein said hub is biased relative to said gear shaft whereby said hub rotates cog inwardly from said hub opening when key is in a disengagement position.

27. A damper apparatus of claim 26, wherein said cog rotates about an axis parallel to said gear shaft axis.

28. A damper apparatus of claim 27, wherein said cog is mounted on a cog pin rotatable in slots in said gear shaft.

29. A damper apparatus of claim 27, further comprising two sets of radially distant cog pin slots in said gear shaft wherein said cog pin is mounted in one of said sets for one of clockwise movement and counterclockwise movement of hub about said gear shaft.

30. A damper apparatus of claim 27, wherein said key is held in an engagement position by a releasable member.

31. A damper apparatus of claim 30, wherein said releasable member comprises a cable attached to a meltable thermal fuse, for disengagement at a predetermined temperature.

32. A damper apparatus of claim 26 wherein said key has an engagement surface and a disengagement surface, said key axially movable for contact of said cog with one of said engagement surface and said disengagement surface.

33. A damper apparatus of claim 26 wherein said key is rotatable about a pivot pin mounted in said gear shaft at a right angle to said gear shaft axis, and having an engagement surface and a disengagement surface oblique to said engagement surface.