Abstract: A silencer module for an air handling unit includes a first baffle and a second baffle spaced apart from the first baffle to form an air channel between the first baffle and the second baffle. The air channel is configured to receive a fluid flow and direct the fluid flow through the silencer module. The silencer module also includes a reactive acoustic feature formed in the first baffle. The reactive acoustic feature includes an attenuation profile configured to reduce propagation of tonal acoustic waves through the air channel.

Abstract: The present disclosure relates to a silencer module for a silencer bank of an air handling unit. The silencer module includes a support shell having a first inner wall and a second inner wall opposite the first inner wall. The silencer module also includes a first baffle coupled to the first inner wall, where the first baffle includes a first perforated baffle sheet, and a second baffle coupled to the second inner wall, where the second baffle includes a second perforated baffle sheet. The silencer module further includes an air flow gap that extends between the first perforated baffle sheet and the second perforated baffle sheet, where the air flow gap has a width that is substantially constant along a dimension of the first perforated baffle sheet and the second perforated baffle sheet that extends generally parallel to a direction of air flow through the air flow gap.

Abstract: A noise suppression apparatus for an air handling unit includes an inlet section connectable to a fan of the air handling unit. The inlet section includes a forward wall spaced apart from an aft wall to define an internal chamber, and an inlet wall extending between the forward wall and the aft wall, the inlet wall defining an inlet air opening. A plurality of internal walls in the inlet wall define a plurality of resonator openings that each open to at least one of a plurality of resonator sections within the internal chamber. The plurality of resonator sections include at least one quarter wave tube section and at least one Helmholtz resonator section. One or more resonator sections are configured to attenuate noise generated by the fan at two or more frequencies. At least one resonator opening of the plurality of resonator openings opens to a plurality of resonator sections.

Abstract: Aspects of the present disclosure include a casing comprising an air inlet and an air outlet, a fan configured to move air from the air inlet to the air outlet, and a tunable sound attenuating module having an opening at a first end of the tunable sound attenuating module, a cavity, and a back wall at a second end of the tunable sound attenuating module, wherein: the tunable sound attenuating module is oriented such that the back wall is closer to the fan than the opening, and a length of tunable sound attenuating module is substantially one fourth of the acoustic wavelength of a sound generated by the fan.

Abstract: The present disclosure relates to a silencer module for a silencer bank of an air handling unit. The silencer module includes a support shell having a first inner wall and a second inner wall opposite the first inner wall. The silencer module also includes a first baffle coupled to the first inner wall, where the first baffle includes a first perforated baffle sheet, and a second baffle coupled to the second inner wall, where the second baffle includes a second perforated baffle sheet. The silencer module further includes an air flow gap that extends between the first perforated baffle sheet and the second perforated baffle sheet, where the air flow gap has a width that is substantially constant along a dimension of the first perforated baffle sheet and the second perforated baffle sheet that extends generally parallel to a direction of air flow through the air flow gap.

Abstract: A noise suppression apparatus for an air handling unit includes an inlet section connectable to a fan of the air handling unit. The inlet section includes a forward wall spaced apart from an aft wall to define an internal chamber, and an inlet wall extending between the forward wall and the aft wall, the inlet wall defining an inlet air opening. A plurality of internal walls in the inlet wall define a plurality of resonator openings that each open to at least one of a plurality of resonator sections within the internal chamber. The plurality of resonator sections include at least one quarter wave tube section and at least one Helmholtz resonator section. One or more resonator sections are configured to attenuate noise generated by the fan at two or more frequencies. At least one resonator opening of the plurality of resonator openings opens to a plurality of resonator sections.

Abstract: The present disclosure relates to a silencer module for a silencer bank of an air handling unit. The silencer module includes a support shell having a first inner wall and a second inner wall opposite the first inner wall. The silencer module also includes a first baffle coupled to the first inner wall, where the first baffle includes a first perforated baffle sheet, and a second baffle coupled to the second inner wall, where the second baffle includes a second perforated baffle sheet. The silencer module further includes an air flow gap that extends between the first perforated baffle sheet and the second perforated baffle sheet, where the air flow gap has a width that is substantially constant along a dimension of the first perforated baffle sheet and the second perforated baffle sheet that extends generally parallel to a direction of air flow through the air flow gap.

Abstract: A silencer module for an air handling unit includes a first baffle and a second baffle spaced apart from the first baffle to form an air channel between the first baffle and the second baffle. The air channel is configured to receive a fluid flow and direct the fluid flow through the silencer module. The silencer module also includes a reactive acoustic feature formed in the first baffle. The reactive acoustic feature includes an attenuation profile configured to reduce propagation of tonal acoustic waves through the air channel.

Abstract: A centrifugal blower assembly includes a scroll wall, a pair of opposing sidewalls, and a cutoff plate. The scroll wall is positioned between the pair of opposing sidewalls such that the scroll wall and opposing sidewalls together define a blower chamber and a blower outlet. The scroll wall extends circumferentially between a cutoff point to an end point and defines a cutout extending circumferentially from the cutoff point. The scroll wall, the pair of opposing sidewalls, and the cutoff point define a blower outlet, wherein the blower outlet defines a blower outlet area. The cutoff plate extends circumferentially from the end point. The cutoff plate defines a notch defining a notch area, the notch area and the blower outlet area define a total blower outlet area, wherein the notch includes a center portion that defines a portion of an elliptical shape.

Abstract: A centrifugal blower assembly includes a scroll wall, a pair of opposing sidewalls, and a cutoff plate. The scroll wall is positioned between the pair of opposing sidewalls such that the scroll wall and opposing sidewalls together define a blower chamber and a blower outlet. The scroll wall extends circumferentially between a cutoff point to an end point and defines a cutout extending circumferentially from the cutoff point. The scroll wall, the pair of opposing sidewalls, and the cutoff point define a blower outlet, wherein the blower outlet defines a blower outlet area. The cutoff plate extends circumferentially from the end point. The cutoff plate defines a notch defining a notch area, the notch area and the blower outlet area define a total blower outlet area, wherein the notch includes a center portion that defines a portion of an elliptical shape.

Abstract: A centrifugal blower assembly includes a scroll wall, a pair of opposing sidewalls, and an adjustable cutoff plate. The scroll wall is positioned between the pair of opposing sidewalls such that the scroll wall and opposing sidewalls together define a blower chamber and a blower outlet. The scroll wall extends circumferentially between a cutoff point to an end point and defines a cutout extending circumferentially from the cutoff point. The scroll wall, the pair of opposing sidewalls, and the cutoff point define a blower outlet. The blower outlet defines a blower outlet area. The adjustable cutoff plate is adjustably positioned within the cutout to define a notch defining a notch area. The notch area and the blower outlet area define a total blower outlet area.

Abstract: A noise suppression apparatus for an air handling unit includes an inlet section connectable to a fan of the air handling unit. The inlet section includes a forward wall spaced apart from an aft wall to define an internal chamber, and an inlet wall extending between the forward wall and the aft wall, the inlet wall defining an inlet air opening. A plurality of internal walls in the inlet wall define a plurality of resonator openings that each open to at least one of a plurality of resonator sections within the internal chamber. The plurality of resonator sections include at least one quarter wave tube section and at least one Helmholtz resonator section. One or more resonator sections are configured to attenuate noise generated by the fan at two or more frequencies. At least one resonator opening of the plurality of resonator openings opens to a plurality of resonator sections.

Abstract: Aspects of the present disclosure include a casing comprising an air inlet and an air outlet, a fan configured to move air from the air inlet to the air outlet, and a tunable sound attenuating module having an opening at a first end of the tunable sound attenuating module, a cavity, and a back wall at a second end of the tunable sound attenuating module, wherein: the tunable sound attenuating module is oriented such that the back wall is closer to the fan than the opening, and a length of tunable sound attenuating module is substantially one fourth of the acoustic wavelength of a sound generated by the fan.

Abstract: The present disclosure relates to a silencer module for a silencer bank of an air handling unit. The silencer module includes a support shell having a first inner wall and a second inner wall opposite the first inner wall. The silencer module also includes a first baffle coupled to the first inner wall, where the first baffle includes a first perforated baffle sheet, and a second baffle coupled to the second inner wall, where the second baffle includes a second perforated baffle sheet. The silencer module further includes an air flow gap that extends between the first perforated baffle sheet and the second perforated baffle sheet, where the air flow gap has a width that is substantially constant along a dimension of the first perforated baffle sheet and the second perforated baffle sheet that extends generally parallel to a direction of air flow through the air flow gap.

Abstract: A centrifugal blower assembly includes a scroll wall, a pair of opposing sidewalls, and an adjustable cutoff plate. The scroll wall is positioned between the pair of opposing sidewalls such that the scroll wall and opposing sidewalls together define a blower chamber and a blower outlet. The scroll wall extends circumferentially between a cutoff point to an end point and defines a cutout extending circumferentially from the cutoff point. The scroll wall, the pair of opposing sidewalls, and the cutoff point define a blower outlet. The blower outlet defines a blower outlet area. The adjustable cutoff plate is adjustably positioned within the cutout to define a notch defining a notch area. The notch area and the blower outlet area define a total blower outlet area.

Abstract: A forward curved blower wheel has fan blades having relatively small leading edge blades angles and a relatively lengthy mean camber lines. The blower wheel also comprises leading edge notches adjacent its blower wheel inlet. The leading edge notches eliminate buffeting that would occur with such blades if such notches were not present.

Abstract: A forward curved blower wheel has fan blades having relatively small leading edge blades angles and a relatively lengthy mean camber lines. The blower wheel also comprises leading edge notches adjacent its blower wheel inlet. The leading edge notches eliminate buffeting that would occur with such blades if such notches were not present.