Abstract: Transducers are provided including a piezoelectric block having first and second opposing surfaces; a first conductive flexible support layer on the first surface of the piezoelectric block, the first flexible support layer having a first thickness; and a second flexible support layer on the second surface of the piezoelectric block, the second flexible support layer having a second thickness. Related devices are also provided.

Abstract: Transducers are provided including a piezoelectric block having first and second opposing surfaces; a first non-piezoelectric layer on the first surface of the piezoelectric block, the first layer including a low density material having a first thickness; and a second non-piezoelectric layer on the second surface of the piezoelectric block, the second layer including a high density material having a second thickness, the second thickness being different from the first thickness and being at least two times the first thickness. Related devices and methods are also provided.

Abstract: An acoustic sensor includes a side wall, closed at each end by an end wall, to form a substantially cylindrical cavity, a transmitter and a receiver operatively associated with first and second respective end walls. Properties of the relative dimensions of the cavity are configured to create a desired oscillatory motion of the end walls, and oscillations of a fluid pressure in the cavity, to generate an electrical signal via the receiver to be output from the sensor. An array of acoustic sensors can be connected to allow calibration of one of the array of sensors.

Abstract: A fluid pump comprising a flow channel containing an fluid inlet and a fluid outlet and bounded by two side walls, a substantially planar flap positioned inside the flow channel, and an actuator capable of transmitting an oscillating force or torque to the flap, where the side walls extend from the inlet to the outlet and are substantially planar and parallel to the flap and extend beyond the downstream end of the flap towards the outlet by a distance such that ld?lf/2, where lf is the length of the flap, where the side wall separation, h, length, lw, and width, ww, satisfy the relationships: lw>h and ww>h, whereby in use, the actuator drives oscillatory motion of the flap in a direction substantially perpendicular to the side walls with motion of the flap having larger amplitude near the outlet than near the inlet.

Abstract: A dual-frequency ultrasound transducer, comprising a piezo-electric element bonded to a substrate, has two resonant vibration modes: a low frequency mechanical bending resonance mode and a relatively high frequency thickness resonance mode. The low frequency bending resonance mode occurs when the piezo-electric element is excited, in use, by a voltage which includes a low frequency oscillating component. The high frequency thickness resonance mode occurs when the piezo-electric element is excited, in use, by a voltage which includes a relatively high frequency oscillating component. The transducer may include a mounting arrangement, such as a support ring securing the periphery of the substrate to an underlying base layer that enhances the depth of penetration and focus of the ultrasound.

Abstract: A print head comprising a nozzle plate having a plurality of nozzles extending therethrough, a piezoelectric bending mode actuator associated with each nozzle and connected with the respective nozzle so as to provide a plurality of independently actuatable nozzles, and a mount for, in use, connecting the nozzle plate to a liquid printer, wherein, in use, each nozzle can be driven at its resonant frequency such that motion of the driven nozzle causes liquid to be ejected only from the driven nozzle.

Abstract: A fluid pump comprising one or two cavities which, in use, contains a fluid to be pumped, the chamber or chambers having a substantially cylindrical shape bounded by first and second end walls and a side wall; an actuator which, in use, causes oscillatory motion of the first end wall(s) in a direction substantially perpendicular to the plane of the first end wall(s); and whereby, in use, these axial oscillations of the end walls drive radial oscillations of the fluid pressure in the main cavity; and wherein an isolator forms at least a portion of the first end wall between the actuator and the side wall and includes conductive tracks, wherein electrical connection is made to the actuator via the conductive tracks included within the isolator.

Abstract: An acoustic sensor includes a side wall, closed at each end by an end wall, to form a substantially cylindrical cavity, a transmitter and a receiver operatively associated with first and second respective end walls. Properties of the relative dimensions of the cavity are configured to create a desired oscillatory motion of the end walls, and oscillations of a fluid pressure in the cavity, to generate an electrical signal via the receiver to be output from the sensor. An array of acoustic sensors can be connected to allow calibration of one of the array of sensors.

Abstract: A valve for controlling the flow of fluid having first (16) and second (14) plates with offsetting apertures and a sidewall (12) disposed between the plates around the perimeter of the plates to form a cavity (15) in fluid communication with the apertures is disclosed. The valve further comprises a flap (17) disposed and moveable between the first and second plates and having apertures (22) substantially offset from the apertures (20) of one plate (16) and substantially aligned with the apertures (18) of the other plate (14). The flap is motivated between the two plates in response to a change in direction of the differential pressure of fluid across the valve.

Abstract: A fluid pump comprising a chamber which, in use, contains a fluid to be pumped, the chamber including a main cavity having a substantially cylindrical shape bounded by first and second end walls and a side wall and a secondary cavity extending radially outwards of the main cavity, one or more actuators which, in use, cause oscillatory motion of the first end wall in a direction substantially perpendicular to the plane of the first end wall, and whereby, in use, the axial oscillations of the end walls drive radial oscillations of the fluid pressure in the main cavity, and wherein the secondary cavity spaces the side wall from the first end wall such that the first end wall can move relative to the side wall when the actuator is activated.

Abstract: A pump comprising a side wall closed at each end by an end wall forming a cavity for, in use, containing a fluid, one or more actuators each operatively associated with one or more of the end walls to cause an oscillatory motion of the associated end wall(s) whereby, in use, these axial oscillations of the end wall(s) drive substantially radial oscillations of the fluid pressure in the cavity, two or more apertures in the cavity, a valve disposed in at least one of the apertures, wherein the actuator(s) is arranged to be non-axisymmetric in use such that, in use, a pressure oscillation with at least one nodal diameter is generated within the cavity.

Abstract: A print head comprising a nozzle plate having a plurality of nozzles extending therethrough, a piezoelectric bending mode actuator associated with each nozzle and connected with the respective nozzle so as to provide a plurality of independently actuatable nozzles, and a mount for, in use, connecting the nozzle plate to a liquid printer, wherein, in use, each nozzle can be driven at its resonant frequency such that motion of the driven nozzle causes liquid to be ejected only from the driven nozzle.

Abstract: A pump having a substantially cylindrical shape and defining a cavity formed by a side wall closed at both ends by end walls wherein the cavity contains a fluid is disclosed. The pump further comprises an actuator operatively associated with at least one of the end walls to cause an oscillatory motion of the driven end wall to generate displacement oscillations of the driven end wall within the cavity. The pump further comprises an isolator operatively associated with a peripheral portion of the driven end wall to reduce dampening of the displacement oscillations. The pump further comprises a valve for controlling the flow of fluid through the valve. The valve has first and second plates with offsetting apertures and a sidewall disposed between the plates around the perimeter of the plates to form a cavity in fluid communication with the apertures.

Abstract: A valve for controlling the flow of fluid having first (16) and second (14) plates with offsetting apertures and a sidewall (12) disposed between the plates around the perimeter of the plates to form a cavity (15) in fluid communication with the apertures is disclosed. The valve further comprises a flap (17) disposed and moveable between the first and second plates and having apertures (22) substantially offset from the apertures (20) of one plate (16) and substantially aligned with the apertures (18) of the other plate (14). The flap is motivated between the two plates in response to a change in direction of the differential pressure of fluid across the valve.

Abstract: A fluid pump comprising one or more actuators, two end walls, a side wall; a cavity which, in use, contains fluid, the cavity having a substantially cylindrical shape bounded by the end walls and the side walls, at least two apertures through the cavity walls, at least one of which is a valved aperture, wherein the cavity radius, a, and height, h, satisfy the following inequalities: a/h is greater than 1.2; and h2/a is greater than 4×10?10 m; and wherein, in use, the actuator causes oscillatory motion of one or both end walls in a direction perpendicular to the plane of the end walls; whereby, in use, the axial oscillations of the end walls drive radial oscillations of fluid pressure in the cavity.

Abstract: A pump having a substantially cylindrical shape and defining a cavity formed by a side wall closed at both ends by end walls wherein the cavity contains a fluid is disclosed. The pump further comprises an actuator operatively associated with at least one of the end walls to cause an oscillatory motion of the driven end wall to generate displacement oscillations of the driven end wall within the cavity. The pump further comprises an isolator operatively associated with a peripheral portion of the driven end wall to reduce dampening of the displacement oscillations. The pump further comprises a valve for controlling the flow of fluid through the valve. The valve has first and second plates with offsetting apertures and a sidewall disposed between the plates around the perimeter of the plates to form a cavity in fluid communication with the apertures.

Abstract: A gas flow generator comprising: an ultrasonic driver comprising a piezoelectric or electrostrictive transducer mounted on a substrate, operation of the transducer being arranged to cause the driver to bend; a first membrane disposed on or formed integrally with the transducer or the substrate; and a second membrane mounted substantially parallel with the driver and spaced a given distance therefrom, one of the membranes being perforate, whereby ultrasonic bending of the driver on actuation of the transducer causes a gas flow through the perforate membrane.

Abstract: A fluid pump comprising one or more actuators, two end walls, a side wall; a cavity which, in use, contains fluid, the cavity having a substantially cylindrical shape bounded by the end walls and the side walls, at least two apertures through the cavity walls, at least one of which is a valved aperture, wherein the cavity radius, a, and height, h, satisfy the following inequalities: a/h is greater than 1.2; and h2/a is greater than 4×10?10 m; and wherein, in use, the actuator causes oscillatory motion of one or both end walls in a direction perpendicular to the plane of the end walls; whereby, in use, the axial oscillations of the end walls drive radial oscillations of fluid pressure in the cavity.