A respiratory assistance device 10 includes: a mask 13 having an expiratory hole 13a; an expiratory valve 15 provided in the mask 13, for opening and closing the expiratory hole 13a; and a control unit 17 for performing overall control on the entire device. The mask 13 and the expiratory valve 15 together form an opening and closing device. The expiratory valve 15 is deformable by deformation of a piezo element 15a. The expiratory valve 15 is disposed on an inner surface 13f so that a deformation direction thereof, i.e., a thickness direction thereof, extends along the inner surface 13f of the mask 13 and a side surface 15m slides along the inner surface 13f by the deformation thereof.

A respiratory assistance device 10 includes: a mask 13 having an expiratory hole 13a; an expiratory valve 15 provided in the mask 13, for opening and closing the expiratory hole 13a; and a control unit 17 for performing overall control on the entire device. The mask 13 and the expiratory valve 15 together form an opening and closing device. The expiratory valve 15 is deformable by deformation of a piezo element 15a. The expiratory valve 15 is disposed on an inner surface 13f so that a deformation direction thereof, i.e., a thickness direction thereof, extends along the inner surface 13f of the mask 13 and a side surface 15m slides along the inner surface 13f by the deformation thereof.

A vortex ring generation device includes a casing and an extrusion mechanism. The casing has a gas passage and a discharge port. The extrusion mechanism extrudes gas in the gas passage such that the gas in a vortex ring shape is discharged from the discharge port. V (m.sup.3) represents an extrusion volume, D (m) represents a diameter of the discharge port, L (m) represents a length of a cylinder having the diameter D and the volume V, and U (m/s) represents a discharge flow rate 0.045≤D≤0.135, 0.15≤L≤0.35, and 3≤U≤5.

In various embodiments, a cooling device for dissipating heat generated in an electronic or electrochemical device includes a substrate, multiple benders arranged on the substrate, and supply circuitry for supplying an electric field to actuate the benders for causing movement thereof, thereby producing an air flow.

In various embodiments, a cooling device for dissipating heat generated in an electronic or electrochemical device includes a substrate, multiple benders arranged on the substrate, and supply circuitry for supplying an electric field to actuate the benders for causing movement thereof, thereby producing an air flow.

The device for generating an air flow for cooling a heat dissipating electronic element such as an LED comprises a channel (12,56) extending between an inlet portion (18) upstream of the air flow to be generated and an outlet portion (20) downstream of the air flow to be generated, wherein the channel (12,56) comprises at least two substantially opposite side surfaces (14). Moreover, the device is provided with a first bendable air ventilating blade (10,58) arranged within the channel (12,56) and having an overall longitudinal extension substantially coinciding with the extension of the channel (12,56), with a first longitudinal end (24,62) arranged upstream of the air ventilating blade (10,58) flow to be generated and a second end (28,70) arranged downstream of the air flow to be generated. The first air ventilating blade (10,58) with its first end (24,62) is fixedly arranged and has its second end (28,70) is reciprocatingly arranged. Furthermore, the device comprises a driving means (32,34,36,66,68) for reciprocating the second end (28,70) of the air ventilating blade (10,58) in a direction between the two substantially opposite side surfaces of the channel (12,56).

The device for generating an air flow for cooling a heat dissipating electronic element such as an LED comprises a channel (12,56) extending between an inlet portion (18) upstream of the air flow to be generated and an outlet portion (20) downstream of the air flow to be generated, wherein the channel (12,56) comprises at least two substantially opposite side surfaces (14). Moreover, the device is provided with a first bendable air ventilating blade (10,58) arranged within the channel (12,56) and having an overall longitudinal extension substantially coinciding with the extension of the channel (12,56), with a first longitudinal end (24,62) arranged upstream of the air ventilating blade (10,58) flow to be generated and a second end (28,70) arranged downstream of the air flow to be generated. The first air ventilating blade (10,58) with its first end (24,62) is fixedly arranged and has its second end (28,70) is reciprocatingly arranged. Furthermore, the device comprises a driving means (32,34,36,66,68) for reciprocating the second end (28,70) of the air ventilating blade (10,58) in a direction between the two substantially opposite side surfaces of the channel (12,56).

An airflow generator and an array of airflow generators are provided for use with an object where each of the airflow generators includes a flexible structure having a first side spaced from a portion of the object to define an air space therebetween and at least one piezoelectric structure located on the flexible structure.

An airflow generator and an array of airflow generators are provided for use with an object where each of the airflow generators includes a flexible structure having a first side spaced from a portion of the object to define an air space therebetween and at least one piezoelectric structure located on the flexible structure.

An air-cooling system (10, 110, 210) utilizing a synthetic jet or airflow generator (20, 120, 220) and airflow generators utilizing piezoelectrics (26, 126, 226) to cool heat-emitting elements (12, 112, 212). Actuation of the piezoelectrics (26, 126, 226) results in movement of one or more flexible structures (22, 24, 122, 124, 221) to increase the volume of one or more cavities (28, 30, 32, 128, 228, 230, 232) to draw air in and then decrease the volume of the one or more cavities (28, 30, 32, 128, 228, 230, 232) to push out the drawn in air.