Replaceable capture hoods for recirculating, self-contained ventilation system

1. A ventilation system, comprising

a hood supporting unit, wherein said hood supporting unit includes a base, a riser duct, and an exhaust, wherein said riser duct has a top end, wherein said riser duct extends in a first direction with respect to said base, wherein said first direction is at a right angle to said base, wherein said base includes a second duct section, wherein said second duct section extends horizontally through said base;

a plurality of removable and replaceable capture hoods, wherein each of said plurality of removable and replaceable capture hoods includes a duct, a hood portion, and a connection portion, wherein said hood portion has an intake and wherein said connection portion has a bottom end, wherein said hood portions of said plurality of removable and replaceable capture hoods have different shapes, wherein each said bottom end is configured for connection with said riser duct top end, wherein said bottom ends of said connection portions of said plurality of removable and replaceable capture hoods are identical so each of said plurality of removable and replaceable capture hoods can connect to said top end of said riser duct of said hood supporting unit; and

a motor and a blower, wherein said motor and said blower are located to provide air movement in a path in to said intake in said hood portion, then through said duct in said removable and replaceable capture hood, then through said riser duct top end, then through said riser duct, then through said second duct in said base, and then out of said exhaust.

2. The ventilation system, as recited in claim 1 , wherein said exhaust is positioned for exhausting air to said intake to provide an air curtain.

3. The ventilation system, as recited in claim 2 , wherein said air curtain is for retaining air within said recirculating ventilation system.

4. The ventilation system, as recited in claim 2 , wherein said exhaust is positioned to direct air toward said intake to form said air curtain.

5. The ventilation system, as recited in claim 2 , wherein said exhaust includes a directing member to direct air toward said intake to form said air curtain.

6. The ventilation system, as recited in claim 5 , wherein said directing member includes an adjustable directing member.

7. The ventilation system as recited in claim 6 , wherein said adjustable directing member includes an adjustable air louver unit.

8. The ventilation system as recited in claim 7 , wherein said adjustable air louver unit includes a curved portion.

9. The ventilation system as recited in claim 8 , wherein said adjustable air louver unit has a louver axis, wherein said adjustable air louver unit further includes a wing having an axis perpendicular to said louver axis.

10. The ventilation system as recited in claim 2 , wherein said base is configured for supporting an appliance that may produce polluted air, wherein said intake is positioned to take in said polluted air, wherein said exhaust is located on said base to provide said air curtain for retaining said polluted air substantially over said base.

11. The ventilation system as recited in claim 10 , wherein said hood has a curved portion for directing rising air toward said intake.

12. The ventilation system as recited in claim 10 , further comprising a directing member, wherein when said directing member is positioned for directing exhaust air toward said intake to provide said air curtain, said polluted air is retained substantially over said base.

13. The ventilation system as recited in claim 10 , further comprising an ultraviolet light source positioned to treat said polluted air.

14. The ventilation system as recited as claimed in claim 10 , further comprising a catalytic converter positioned to treat said polluted air.

15. The ventilation system as recited in claim 2 , further comprising an appliance that generates polluted air, wherein said appliance is mounted so said polluted air is contained by said air curtain and captured by said intake.

16. The ventilation system as recited in claim 1 , wherein said blower includes a tangential fan.

17. The ventilation system as recited in claim 16 , further comprising a tangential fan housing, wherein said tangential fan housing includes said riser duct and said second duct section in said base.

18. The ventilation system as recited in claim 1 , further comprising a filter frame for holding a plurality of removable filters.

19. The ventilation system, as recited in claim 18 , wherein said riser duct houses said motor, said blower, and said filter frame.

20. The ventilation system as recited in claim 1 , further comprising a device for removing pollution from said polluted air, wherein said device for removing pollution from said polluted air is within said riser duct.

21. The ventilation system as recited in claim 20 , wherein said device for removing pollution from said polluted air includes at least one component from the group consisting of a particulate filter, an odor filter, a grease filter, and a grease trough.

22. The ventilation system as recited in claim 1 , further comprising a fire damper that automatically closes in the presence of a fire.

23. The ventilation system as recited in claim 1 , further comprising an appliance electrical connection and a power disconnector, wherein said appliance electrical connection is for providing power to an appliance mounted on said hood supporting unit, wherein said power disconnector is automatically activated to shut power to said appliance electrical connection in case of a fire.

24. The ventilation system as recited in claim 1 , further comprising a fire suppressant system for dispensing fire suppressant.

25. The ventilation system as recited in claim 1 , wherein at least one of said plurality of replaceable capture hoods includes an adjustable air intake slot.

26. The ventilation system, as recited in claim 1 , wherein said hood supporting unit includes a fan and filters.