Air cleaner including an improved airflow path

1. An air cleaner including an improved airflow path, comprising:

a duct extending between an air inlet of the air cleaner and an air outlet, with the duct being configured to conduct an airflow and comprising:

an input region located downstream of one or more air cleaning components and upstream of an impeller;

a curved transition region downstream of the input region, with the curved transition region transitioning the airflow from an air inlet orientation to an air outlet orientation;

an expansion output region downstream of the curved transition region, with the expansion output region allowing the airflow to expand;

the impeller located in the curved transition region of the air duct wherein the airflow is smoothly conducted from the air inlet to the air outlet by the duct; and

a rounded nose comprising a tip, wherein the tip partially extends into the expansion output region towards the air outlet.

2. The air cleaner of claim 1 , with the air outlet being non-linear with the air inlet.

3. The air cleaner of claim 1 , with the air outlet being substantially angled with respect to the air inlet.

4. The air cleaner of claim 1 , with the air outlet being substantially at a right angle to the air inlet.

5. The air cleaner of claim 1 , with the impeller comprising a cross-flow fan impeller disposed substantially lengthwise in the curved transition region.

6. The air cleaner of claim 1 , further comprising a cutoff region between the input region and the expansion output region, with the cutoff region comprising a predetermined cutoff gap between the impeller and a chassis of the air cleaner and wherein the tip of the rounded nose is disposed downstream of the cutoff region.

7. The air cleaner of claim 1 , further comprising an outlet grill substantially at the air outlet and including one or more angled grill members at a predetermined angle to the airflow at the air outlet.

8. An air cleaner including an improved airflow path, comprising:

a duct extending between an air inlet of the air cleaner and an air outlet, with the air outlet being substantially non-linear with the air inlet and with the duct being configured to conduct an airflow and comprising:

an input region located downstream of one or more air cleaning components and upstream of an impeller;

a curved transition region downstream of the input region, with the curved transition region transitioning the airflow from an air inlet orientation to an air outlet orientation;

an expansion output region downstream of the curved transition region, with the expansion output region allowing the airflow to expand;

the impeller located in the curved transition region of the air duct, wherein the airflow is smoothly conducted from the air inlet to the air outlet by the duct;

a cutoff region between the input region and the expansion output region;

a cutoff gap disposed in the cutoff region for increasing a back pressure of airflow therein; and

a rounded nose including a tip, wherein the tip partially extends into the expansion output region.

9. The air cleaner of claim 8 , with the air outlet being substantially angled with respect to the air inlet.

10. The air cleaner of claim 8 , with the air outlet being substantially at a right angle to the air inlet.

11. The air cleaner of claim 8 , with the impeller comprising a cross-flow fan impeller disposed substantially lengthwise in the curved transition region.

12. The air cleaner of claim 8 , further comprising an outlet grill substantially at the air outlet and including one or more angled grill members at a predetermined angle to the airflow at the air outlet.

13. A method of forming an air cleaner including an improved airflow path, the air cleaner comprising:

providing a duct extending between an air inlet and an air outlet of the air cleaner and configures to conduct an airflow;

providing an input region in the duct and located downstream of one or more air cleaning components and upstream of an impeller located in a curved transition region of the duct;

providing the curved transition region in the duct downstream of the input region, with the curved transition region transitioning the airflow from an air inlet orientation to an air outlet orientation;

providing an expansion output region in the duct downstream of the curved transition region, with the expansion out region allowing the airflow to expand; and

reducing fan cutoff noise by providing a rounded nose including a tip that partially extends into the expansion output region towards the air outlet.

14. The method of claim 13 , with the air outlet being non-linear with the air inlet.

15. The method of claim 13 , with the air outlet being substantially angled with respect to the air inlet.

16. The method of claim 13 , with the air outlet being substantially at a right angle to the air inlet.

17. The method of claim 13 , further comprising providing the impeller in the curved transition region of the air duct, wherein the airflow is smoothly conducted from the air inlet to the air outlet by the duct.

18. The method of claim 13 , further comprising providing the impeller in the curved transition region of the air duct, with the impeller comprising a cross-flow fan impeller disposed substantially lengthwise in the curved transition region and wherein the airflow is smoothly conducted from the air inlet to the air outlet by the duct.

19. The method of claim 13 , further comprising providing a cutoff region between the input region and the expansion output region, with the cutoff region comprising a predetermined cutoff gap between the impeller and a chassis the expansion output region of the air cleaner.

20. The method of claim 13 , further comprising providing a cutoff region between the input region and the expansion output region, with the cutoff region comprising a predetermined cutoff gap between the impeller and a chassis of the air cleaner and wherein the rounded nose is disposed downstream of the cutoff region.

21. The method of claim 13 , further comprising providing an outlet grill substantially at the air outlet and including one or more angled grill members at a predetermined angle to the airflow at the air outlet.

22. The air cleaner of claim 1 , with the expansion outlet region being a partial spiral or scroll shape with increasing radius.

23. The air cleaner of claim 1 , wherein the rounded nose is disposed downstream of the impeller.

24. The air cleaner of claim 8 , wherein the cutoff gap is small.

25. The air cleaner of claim 8 , wherein the cutoff region is adjacent to the impeller.

26. An air cleaner including an improved airflow path, comprising:

an impeller; and

a duct to conduct an airflow extending between an air inlet of the air cleaner and an air outlet comprising:

an input region located upstream of the impeller;

a transition region downstream of the input region, with the transition region transitioning the airflow from an air inlet orientation to an air outlet orientation and with the transition region expanding in cross-sectional area from the air inlet to air outlet; and

an expansion output region downstream of the impeller with a portion of the expansion output region having a partial spiral or scroll shape with increasing radius;

wherein the impeller is located in the transition region of the air duct wherein the airflow upstream of the impeller is tangential with respect to the airflow downstream of the impeller.

27. The air cleaner of claim 26 with the air outlet being substantially non-linear with the air inlet.

28. The air cleaner of claim 26 further comprising a rounded nose partially extending into the expansion output region.

29. The air cleaner of claim 26 with the duct having no sharp corners.

30. The air cleaner of claim 26 with the duct being free of obstructions.

31. The air cleaner of claim 26 with the expansion output region including a larger cross-sectional area adjacent to the impeller.