One feature pertains to an acoustic attenuation device. The acoustic attenuation device comprises a fan assembly, the fan assembly including at least one fan module that directs airflow in at least one direction, wherein the at least one fan module includes a top surface and a bottom surface, a plurality of air deflectors mounted to the top surface and the bottom surface of the at least one fan module, wherein the plurality of air deflectors include a plurality of surfaces, and wherein at least one of the plurality of surfaces is an angled surface that redirects the airflow 90-degrees, and acoustic attenuating foam, wherein the acoustic attenuating foam has a two-dimensional (2-D) surface and is applied to interior surfaces of the plurality of surfaces.

Disclosed fans include an impeller and a guide device. The impeller is configured to generate an air flow path having an upstream direction and a downstream direction, and the guide device is positioned in the flow path located on an upstream side of the impeller. The guide device is configured as an intake grid having flat webs having branches and node points, and the webs form a plurality of flow channels configured as grid cells. The webs extend either between two branches or between one branch and a border area and each branch may include three webs that meet. In one configuration, flow channels include channels having a honeycomb cross section. In other example, flow channels may have a rectangular, pentagonal, and/or hexagonal shape. The fan further includes an inlet nozzle having an inlet area, and the guide device is located upstream from the inlet area of the inlet nozzle.

A temperature destratification assembly can include an outer housing. An impeller can be positioned within the outer housing between the inlet and outlet of the outer housing. The impeller can have an impeller hub and a plurality of impeller blades extending radially outward from the impeller hub. The assembly can include an impeller motor configured to rotate the impeller blades about an axis of rotation. A stator can be positioned within the outer housing between the impeller and the outlet of the outer housing. The stator can include a plurality of vanes. The stator vanes can include an upstream edge at the upstream end of the stator, a first surface extending from the upstream edge to the downstream edge of the vane, and a second surface opposite the first surface and extending from the upstream edge to the downstream edge of vane. A plurality of the vanes can have a downstream edge at the outlet of the outer housing.

A blower device includes a pair of fans, a housing, and a lid. The pair of fans generates an airflow on one side in the axial direction along the central axis and is coaxially arranged. The housing has a tubular shape extending along the central axis, accommodates the pair of fans, and has two end surfaces opened in the axial direction. The lids cover axial end surfaces of the housing and provide ventilation. The lid includes an annular portion in contact with the inner peripheral surface of the housing and including a through hole penetrating in the radial direction. The housing includes an engagement protrusion that protrudes radially inward from the inner peripheral surface and engages with the periphery of the through hole.

A straddled vehicle including a radiator, a radiator fan disposed behind the radiator and configured to generate air passing through the radiator and flowing rearward, a fan cover disposed behind the radiator fan and including a lateral blowing port configured to blow out sidewards the air flowing rearward from the radiator, a side cover covering the radiator laterally and having an opening formed therein, an inner panel disposed between the side cover and the radiator, to thereby define an accommodation space between the inner panel and the side cover, and an electrical component disposed in the accommodation space. The inner panel includes a slope that is located rearward of the radiator, slants with respect to aright-and-left direction of the straddled vehicle, is configured to lead the air blown out from the lateral blowing port to the opening in the side cover, and divides the accommodation space.

A refractory metal core (RMC) finishing method according to an exemplary aspect of the present disclosure includes, among other things, performing a plurality of finishing operations on a plurality of RMC samples, analyzing one or more properties of at least a portion of the plurality of RMC samples and selecting a combination of finishing operations for generating an RMC having desirable properties for manufacturing a part free from defects.

A vacuum pump includes a rotor provided with a plurality of rotor blades and a rotor cylinder portion, a driving portion, a bearing, stator blades, a thread groove stator that is disposed downstream of the stator blades and has an inner peripheral surface facing an outer peripheral surface of the rotor cylinder portion, and a heat insulating wall disposed downstream of the thread groove. The heat insulating wall includes a ring-shaped annular portion, and a substantially cylindrical wall portion extending from an inner portion of the annular portion in the radial direction to the upstream side and forming a flow path on the outer peripheral surface side. A first corner portion is formed between an upstream-side surface of the annular portion and the outer peripheral surface of the wall portion, the first corner portion being formed in an arc shape.

A concentrator nozzle attachment for a blower device is disclosed that increases the airflow velocity of the blower without sacrificing the field of the jetting air. The concentrator nozzle is formed of an outer ring with a centrally located guide surface and is placed at the exit of an air tube. As the air exits the air tube, it's forced to flow around the guide surface, thus increasing its velocity. The attachment is secured to the end of the air tube and so does not alter the outer diameter through which the air exits. In this way, air velocity is increased without reducing its effectiveness.

An air cleaner includes a fan that is configured to suck air in an axial direction and discharge air between the axial direction and a radial direction. The air cleaner further includes a fan motor that is configured to rotate the fan. The air cleaner further includes an air guide unit that includes a cylindrical outer wall and an inner wall that is located in a center portion of the outer wall and that defines a space that is configured to receive the fan motor. The air guide unit defines an annular air flow path that is configured to receive air discharged by the fan and that is defined by an inner circumferential surface of the outer wall and an outer circumferential surface of the inner wall. The air guide unit further includes a plurality of guide ribs. The air guide unit further includes a plurality of flow guide protrusions.

A fan, and a silencer that silences a sound generated by the fan are provided, in which the silencer has a resonance characteristic, the silencer is disposed at a position connected to a sound field space of the sound generated by the fan, and a sum of an absorbance and a reflectivity of the silencer at a resonance frequency is 10% to 43% and a standardized half-width of the silencer is more than 0.05 and 0.25 or less.