Centrifugal air blower unit having movable portion

A centrifugal air blower unit for blowing an air to a heat exchanger, the unit comprising:

• a centrifugal multi-blade fan having a rotation axis with an axial direction, an outer circumference and a plurality of blades disposed around the rotation axis of the fan;
• a scroll casing with a nose for accommodating the fan and for providing a first air passage so as to flow the air by an airflow amount;
• and
• an introduction duct having an inner wall for providing a second air passage,
• wherein the fan sucks the air from the axial direction of the rotation axis and blows the air toward the outer circumference of the fan,
• wherein the first air passage has a scroll shape and flows the air blown from the fan,
• wherein the second air passage introduces the air blown from the scroll casing toward the heat exchanger,
• wherein the inner wall of the introduction duct includes a movable portion, which connects to the nose of the scroll casing, and
• wherein the inner wall of the introduction duct is smoothly jointed between the first and second air passages even when the movable portion of the inner wall of the introduction duct is displaced in accordance with the airflow amount of the air blown from the scroll casing.

A centrifugal air blower unit for blowing an air to a heat exchanger, the unit comprising:

• a centrifugal multi-blade fan having a rotation axis with an axial direction, an outer circumference and a plurality of blades disposed around the rotation axis of the fan;
• a scroll casing with an outer periphery for accommodating the fan and for providing a first air passage so as to flow the air by an airflow amount;
• and
• an introduction duct having an inner wall for providing a second air passage,
• wherein the fan sucks the air from the axial direction of the rotation axis and blows the air toward the outer circumference of the fan,
• wherein the first air passage has a scroll shape and flows the air blown from the fan,
• wherein the second air passage introduces the air blown from the scroll casing toward the heat exchanger,
• wherein the inner wall of the introduction duct includes a movable portion, which connects to the inner wall disposed at the outer periphery of the scroll casing, and
• wherein the inner wall of the introduction duct is smoothly jointed between the first and second air passages even when the movable portion of the inner wall of the introduction duct is displaced in accordance with the airflow amount of the air blown from the scroll casing.