Abstract: An air blowing device includes a housing with a suction port and a blow-off port, and a fan placed in the housing. The fan includes a fan case with a tongue section, an impeller, and a motor. The fan case includes an inlet and an outlet, and is shaped such that a space between the impeller and an inner wall of the fan case increases along a rotary direction of the impeller up to a cross section cut along a line between the tongue section and its opposite section. An opening area of the fan case at the tongue section is kept equal or decreases up to the outlet.

Abstract: A multiblade air blower has a multiblade impeller, an orifice, an axially overlaid portion, and an airflow collision prevention device. The multiblade impeller includes a main plate and a blade. The blade is provided at the main plate to form a blade inner periphery. The orifice has an open end and an orifice inner periphery. The open end is positioned toward the main plate from a blade end face. The orifice inner periphery has an inner diameter larger than that of the blade inner periphery, and guides air to the multiblade impeller. The axially overlaid portion is a part where the orifice and the blades are overlaid. The airflow collision prevention device is provided at the blade and at an inner side of the orifice inner periphery. The multiblade air blower suppresses loss of air distribution efficiency and increased noise.

Abstract: A blower drawing air into the air path and discharging air to the discharge duct, including: a frame forming an outer shell; a fan driven by a motor and having a fan outlet, inside the frame; a duct connection part having a duct connection opening, connected to the discharge duct, outside the frame; and an in-frame blow-out part connecting the duct connection part with the fan outlet, inside the frame. The cross-section shape of the air path changes continuously and smoothly at the in-frame blow-out part and the duct connection part, from the fan outlet to the duct connection opening.

Abstract: A multiblade air blower has a multiblade impeller, an orifice, an axially overlaid portion, and an airflow collision prevention device. The multiblade impeller includes a main plate and a blade. The blade is provided at the main plate to form a blade inner periphery. The orifice has an open end and an orifice inner periphery. The open end is positioned toward the main plate from a blade end face. The orifice inner periphery has an inner diameter larger than that of the blade inner periphery, and guides air to the multiblade impeller. The axially overlaid portion is a part where the orifice and the blades are overlaid. The airflow collision prevention device is provided at the blade and at an inner side of the orifice inner periphery. The multiblade air blower suppresses loss of air distribution efficiency and increased noise.

Abstract: Centrifugal impeller (14) of centrifugal air blower (1) has main plate (15); a plurality of blades (18); ring-shaped plate (20); and a cylindrical wall (22). The blades (18) are circumferentially disposed on the side of the outer periphery of front side (17) of main plate (15). Ring-shaped plate (20) is attached to tip sections (19) of blades (18). Cylindrical wall (22) is disposed on the back side (21) of the main plate (15) so as to be concentric therewith. The structure above provides centrifugal impeller (14) and centrifugal air blower (1) with improved air-blow efficiency and noise-reduced operations.

Abstract: A multiblade air blower has a multiblade impeller, an orifice, an axially overlaid portion, and an airflow collision prevention device. The multiblade impeller includes a main plate and a blade. The blade is provided at the main plate to form a blade inner periphery. The orifice has an open end and an orifice inner periphery. The open end is positioned toward the main plate from a blade end face. The orifice inner periphery has an inner diameter larger than that of the blade inner periphery, and guides air to the multiblade impeller. The axially overlaid portion is a part where the orifice and the blades are overlaid. The airflow collision prevention device is provided at the blade and at an inner side of the orifice inner periphery. The multiblade air blower suppresses loss of air distribution efficiency and increased noise.

Abstract: A multi-blade fan including a spirally-shaped casing having an inlet and an outlet; an electric motor disposed inside the casing; a main plate provided perpendicular to a rotation axis of the electric motor and having a ventilation hole; first blades disposed at a side of the inlet of the main plate; and second blades disposed at an opposite side of the inlet of the main plate. Herein, a diameter of the main plate is smaller than an outer diameter of the first and second blades and is larger than an inner diameter of them. Furthermore, an outlet angle of any one or both of the first blade and the second blade is sequentially changed in an axis direction.

Abstract: A centrifugal fan used as a ventilating fan is provided which can increase a range of frequencies of noises in which noises can be suppressed and can adjust frequencies of noises at which noises can be suppressed. The centrifugal fan includes, in an outer casing, a motor that couples an impeller, a casing that surrounds a periphery of the impeller and has a bell-mouthed suction port on one side, and a bell-mouthed orifice that has an opening that is concentric with the suction port and has a diameter equal to or smaller than that of the suction port, wherein a member closing a clearance portion between an end of the orifice and the casing is a noise absorbing structural material, and a space formed by the orifice is a rear air layer, thereby forming a resonance type noise absorbing structure.

Abstract: An air blowing device includes a housing with a suction port and a blow-off port, and a fan placed in the housing. The fan includes a fan case with a tongue section, an impeller, and a motor. The fan case includes an inlet and an outlet, and is shaped such that a space between the impeller and an inner wall of the fan case increases along a rotary direction of the impeller up to a cross section cut along a line between the tongue section and its opposite section. An opening area of the fan case at the tongue section is kept equal or decreases up to the outlet.

Abstract: A blower drawing air into the air path and discharging air to the discharge duct, including: a frame forming an outer shell; a fan driven by a motor and having a fan outlet, inside the frame; a duct connection part having a duct connection opening, connected to the discharge duct, outside the frame; and an in-frame blow-out part connecting the duct connection part with the fan outlet, inside the frame. The cross-section shape of the air path changes continuously and smoothly at the in-frame blow-out part and the duct connection part, from the fan outlet to the duct connection opening.

Abstract: A centrifugal fan having a sound reduction effect for noises in a wide frequency range is provided. The centrifugal fan comprises a motor to which an impeller is connected, a casing which surrounds the impeller and which has a bell-mouth-like suction port, and a bell-mouth-like orifice which has a suction port being concentric with the suction port of the casing and having a diameter as large as that of the suction port of the casing, in an outer shell, providing a plurality of protrusions in a resonant space surrounded by the orifice, the casing, and the outer shell, and providing depressions which are formed so as to be interposed between the protrusions.

Abstract: Centrifugal impeller (14) of centrifugal air blower (1) has main plate (15); a plurality of blades (18); ring-shaped plate (20); and a cylindrical wall (22). The blades (18) are circumferentially disposed on the side of the outer periphery of front side (17) of main plate (15). Ring-shaped plate (20) is attached to tip sections (19) of blades (18). Cylindrical wall (22) is disposed on the back side (21) of the main plate (15) so as to be concentric therewith. The structure above provides centrifugal impeller (14) and centrifugal air blower (1) with improved air-blow efficiency and noise-reduced operations.

Abstract: A multiblade air blower has a multiblade impeller, a casing, an orifice, an axially overlaid portion, and an airflow collision prevention device. The multiblade impeller includes a main plate and a blade. The blade has a blade end face, and is provided at the main plate to form a blade inner periphery. The casing houses the multiblade impeller. The orifice has an open end and an orifice inner periphery. The open end is positioned toward the main plate from the blade end face. The orifice inner periphery has an inner diameter larger than that of the blade inner periphery, and guides air to the multiblade impeller. The axially overlaid portion is a part where the orifice and the blades are overlaid. The airflow collision prevention device is provided at the blade and at an inner side of the orifice inner periphery. With this structure, backflow of air and airflow disturbance at high air volume can be suppressed.

Abstract: A centrifugal fan used as a ventilating fan is provided which can increase a range of frequencies of noises in which noises can be suppressed and can adjust frequencies of noises at which noises can be suppressed. The centrifugal fan includes, in an outer casing, a motor that couples an impeller, a casing that surrounds a periphery of the impeller and has a bell-mouthed suction port on one side, and a bell-mouthed orifice that has an opening that is concentric with the suction port and has a diameter equal to or smaller than that of the suction port, wherein a member closing a clearance portion between an end of the orifice and the casing is a noise absorbing structural material, and a space formed by the orifice is a rear air layer, thereby forming a resonance type noise absorbing structure.

Abstract: A multi-blade fan including a spirally-shaped casing having an inlet and an outlet; an electric motor disposed inside the casing; a main plate provided perpendicular to a rotation axis of the electric motor and having a ventilation hole; first blades disposed at a side of the inlet of the main plate; and second blades disposed at an opposite side of the inlet of the main plate. Herein, a diameter of the main plate is smaller than an outer diameter of the first and second blades and is larger than an inner diameter of them. Furthermore, an outlet angle of any one or both of the first blade and the second blade is sequentially changed in an axis direction.