Abstract: An axial flow fan includes a hub driven to rotate and configured to serve as a rotation axis of the axial flow fan and a blade connected to the hub. The blade has a leading edge and a trailing edge. The trailing edge has an indentation indenting toward the leading edge. The indentation narrows from the trailing edge to the leading edge, and has an apex being a point closest to the leading edge from among the points constituting the indentation. The blade has, at the indentation, a maximum thickness portion at which a thickness of the blade is maximum, and which is positioned radially inside of the apex.

Abstract: An axial fan includes a hub having a rotation shaft and configured to be driven to rotate and blades provided to the hub. The blades each have a front edge portion and a rear edge portion. A first blade section is a section of a portion between the front edge portion and the rear edge portion of each of the blades along a direction in which the blades rotate, and the first blade section is an area of each of the blades that is further inward than an outer periphery edge portion that is a most radially outer periphery in each of the blades. In the first blade section, the blades each have a projection portion and a first recess portion. The projection portion projects from a portion of a pressure surface of each of the blades. The first recess portion recedes from a portion of the pressure surface that is between the projection portion and the rear edge portion.

Abstract: In an axial flow fan, a plurality of blades are rotated about a rotation axis of the plurality of blades to generate an air current. Each of the plurality of blades includes a leading edge portion on a forward side in a rotation direction, and a trailing edge portion on a rearward side in the rotation direction. At the trailing edge portion of the blade, a first recessed portion is formed such that the first recessed portion is recessed toward the leading edge portion. At the leading edge portion of the blade, the second recessed portion is recessed toward the trailing edge portion. Ranges of the first recessed portion and the second recessed portion in a radial direction overlap with each other or completely coincide with each other.

Abstract: An axial-flow fan includes a hub that is to be rotated and defines a rotation axis, and a vane provided on a circumference of the hub. The vane includes a leading edge, a trailing edge, an outer circumferential edge, and an inner circumferential edge. The vane is shaped such that a first line chart in a first diagram includes a downward convex portion that is convex further downward than a first virtual line chart, the first virtual line chart being a linear line connecting a point representing a size of an outlet angle formed at a point of the trailing edge that is at the inner circumferential edge and a point representing a size of the outlet angle formed at a point of the trailing edge that is at the outer circumferential edge.

Abstract: A propeller fan includes a shaft portion disposed on a rotation axis, and a blade disposed on an outer peripheral side of the shaft portion and including a leading edge and a trailing edge. The blade includes a negative pressure surface in which a plurality of recesses are formed, and the plurality of recesses include a first recess and a second recess disposed on the trailing edge side than the first recess in a circumferential direction about the rotation axis as a center. The first recess has a depth larger than a depth of the second recess.

Abstract: An axial-flow fan includes a hub that is to be rotated and defines a rotation axis, and a vane provided on a circumference of the hub. The vane includes a leading edge, a trailing edge, an outer circumferential edge, and an inner circumferential edge. The vane is shaped such that a first line chart in a first diagram includes a downward convex portion that is convex further downward than a first virtual line chart, the first virtual line chart being a linear line connecting a point representing a size of an outlet angle formed at a point of the trailing edge that is at the inner circumferential edge and a point representing a size of the outlet angle formed at a point of the trailing edge that is at the outer circumferential edge.

Abstract: A seismic sensor may include a simple earthquake detection mode in which measured acceleration data is not saved, and which mode is continued in a case in which the measured acceleration is equal to or less than a predetermined first threshold value. An earthquake detection mode may further be included in which the measured acceleration data is saved, and which mode is continued in a case in which the acceleration measured in the simple earthquake detection mode is greater than the first threshold value and equal to or less than a second threshold value that is greater than the first threshold value. An earthquake measurement mode may further be included in which the acceleration data and a spectrum intensity (SI) value are measured and saved, and which mode is continued in a case in which the acceleration measured in the earthquake detection mode is greater than the second threshold value.

Abstract: A package-type flow sensor includes a flow sensor chip having a sensor part configured to detect a flow of fluid, a package including a flat board part, forming an accommodating chamber configured to accommodate the flow sensor chip, and a connection terminal, provided on an outer surface of the board part, and connected to an external board. Further, in this package-type flow sensor, the board part is provided with a first vent hole communicating to inside and outside of the accommodating chamber, the package is provided with a second vent hole communicating to the inside and the outside of the accommodating chamber, at a position different from the board part, and the flow sensor chip is disposed on a flow passage of the fluid formed by the first vent hole and the second vent hole.

Abstract: An axial flow fan includes a hub and a blade provided around the hub and having a leading edge and a trailing edge. The blade has a thickness portion. The thickness portion includes a first thickness portion located adjacent to the leading edge and a second thickness portion located adjacent to the trailing edge.

Abstract: A pressure sensor includes a detection element that detects a change in pressure, and a cover member that accommodates the detection element and that includes a first through hole and a second through hole. Each of the first through hole and the second through hole is provided at a position that does not overlap the detection element in a front view of the respective hole.

Abstract: A detection device for detecting characteristics of a mixed fluid containing different types of substances with different thermal properties within a prescribed range, includes: one or a plurality of heaters for heating the mixed fluid; a plurality of temperature detectors for detecting the temperature of the mixed fluid heated; a flow rate calculation unit for calculating the flow rate of the mixed fluid using the output from at least a portion of the plurality of temperature detectors; a correspondence relation storage unit that stores the correspondence relation between the output from the temperature detectors for a prescribed flow rate and the mixture ratio of the substances in the mixed fluid; and a mixture ratio calculation unit for calculating the mixture ratio of the substances in the mixed fluid on the basis of the output from the temperature detectors and the correspondence relation.

Abstract: A propeller fan includes a shaft portion disposed on a rotation axis, and a blade disposed on an outer peripheral side of the shaft portion and including a leading edge and a trailing edge. The blade includes a negative pressure surface in which a plurality of recesses are formed, and the plurality of recesses include a first recess and a second recess disposed on the trailing edge side than the first recess in a circumferential direction about the rotation axis as a center. The first recess has a depth larger than a depth of the second recess.

Abstract: A propeller fan includes a shaft portion disposed on a rotation axis, and a blade disposed on an outer peripheral side of the shaft portion and including a leading edge and a trailing edge. The blade includes a negative pressure surface in which a plurality of recesses are formed, and the plurality of recesses include a first recess and a second recess disposed on the trailing edge side than the first recess in a circumferential direction about the rotation axis as a center. The first recess has a depth larger than a depth of the second recess.

Abstract: An air-sending device includes a fan and a grille provided downstream of the fan in a direction of airflow generated by the fan. The grille includes a first grille that includes a plurality of first bars spaced from each other, and a second grille that includes a plurality of second bars spaced from each other. The plurality of second bars are more densely arranged than the plurality of first bars. The second grille is provided upstream of the first grille in the direction of the airflow generated by the fan, and spaced from the first grille to face the first grille.

Abstract: An axial flow fan includes a hub driven to rotate and configured to serve as a rotation axis of the axial flow fan and a blade connected to the hub. The blade has a leading edge and a trailing edge. The trailing edge has an indentation indenting toward the leading edge. The indentation narrows from the trailing edge to the leading edge, and has an apex being a point closest to the leading edge from among the points constituting the indentation. The blade has, at the indentation, a maximum thickness portion at which a thickness of the blade is maximum, and which is positioned radially inside of the apex.

Abstract: An axial fan includes a hub having a rotation shaft and configured to be driven to rotate and blades provided to the hub. The blades each have a front edge portion and a rear edge portion. A first blade section is a section of a portion between the front edge portion and the rear edge portion of each of the blades along a direction in which the blades rotate, and the first blade section is an area of each of the blades that is further inward than an outer periphery edge portion that is a most radially outer periphery in each of the blades. In the first blade section, the blades each have a projection portion and a first recess portion. The projection portion projects from a portion of a pressure surface of each of the blades. The first recess portion recedes from a portion of the pressure surface that is between the projection portion and the rear edge portion.

Abstract: An axial fan includes a hub and blades. The hub has a rotating shaft, and is configured to be driven to rotate. The blades are provided to the hub, and each have a front edge portion and a rear edge portion. In a state in which the blades rotate to generate an airflow, the front edge portion is placed most upstream in the airflow, and the rear edge portion is placed most downstream in the airflow. In a shape of the blades rotated and projected onto a meridian plane that covers shapes of the blades and a shape of the rotating shaft, the front edge portion has an outline represented by a front-edge projected portion having a first recess portion formed in a recessed shape that recedes upstream in the airflow, the rear edge portion has an outline represented by a rear-edge projected portion having a second recess portion formed in a recessed shape that recedes upstream in the airflow, and the first recess portion has at least a portion that is formed further radially inside than is the second recess portion.

Abstract: A propeller fan includes a rotary shaft portion that rotates around an axial center and a plurality of blades disposed around an outer circumferential portion of the rotary shaft portion. Each of the plurality of blades has at least one recessed portion that opens at a trailing edge of the blade. The at least one recessed portion has a first side that is close to an inner circumference of the blade. The first side stretches from the trailing edge toward a leading edge of the blade, and is bent toward an outer circumference of the blade.

Abstract: Provided are a heater that heats a fluid, and a temperature detector that detects a temperature of the fluid, and a flow rate of the fluid flowing through a main channel is corrected based on a tendency of a detection value detected by the temperature detector to change over time.

Abstract: A suction tool includes: a hollow cylindrical main pipe having: a rear end side connected to a vacuum cleaner main body; a front end portion in which a main suction port is formed; and a hollow cylindrical sub pipe having: a rear end side at which an inside of the hollow cylindrical sub pipe communicates with an inside of the main pipe; and a front end portion in which a sub suction port is formed. The sub pipe is movable between a retracted position in which the front end portion of the sub pipe is arranged so as to be retracted from the front end portion of the main pipe, and a use position in which the front end portion of the sub pipe is arranged so as to protrude from the front end portion of the main pipe along an axial direction of the main pipe.