Abstract: A liquid feed pump includes a pump housing, a diaphragm forming a pump chamber together with the recessed portion surface and partitioning the pump chamber from the hole, a reciprocating member reciprocatably inserted into the hole and reciprocating to press the diaphragm to deform, a driving member displacing the reciprocating member periodically in a direction of reciprocation, a seal portion sandwiching the diaphragm to seal the diaphragm in a position around an outer peripheral side of the recessed portion surface, a diaphragm receiving surface provided between the seal portion and the opening portion, and its contact area contacting the diaphragm decreases in response to an increase in the displacement of the reciprocating member to the recessed portion surface side and increases in response to an increase in the internal pressure of the pump chamber.

Abstract: A piezoelectric micro-blower includes an inner case to which a peripheral portion of a vibrating plate including a piezoelectric element is fixed such that a blower chamber is defined between the inner case and the vibrating plate and an outer case arranged to cover an outer periphery of the inner case with a gap therebetween. The inner case is elastically retained in the outer case by a plurality of connecting portions. A first opening is provided in a top plate portion of the inner case that faces a central portion of the vibrating plate, and a second opening is provided in a top plate portion of the outer case that faces the first opening. A central space is provided between the top plate portions, and fluid introduced from the outside is guided to the central space through the gap between the inner and outer cases. The vibrating plate is driven in a bending mode so that air is sucked into the central space and is discharged through the second opening.

Abstract: A fluid transportation device includes a valve seat, a valve cap, a valve membrane, and an actuating module. The valve seat has an outlet channel and an inlet channel. The valve cap has a tilt structure. The valve membrane has an inlet valve structure and an outlet valve structure. The actuating module has a vibration film and an actuator. When the fluid transportation device is in a non-actuation status, a pressure cavity with a gradually-increasing depth is defined. When a voltage is applied on the actuator to result in deformation of the actuator, the vibration film generates a pressure difference to push the fluid. The fluid is introduced into the inlet valve structure through the inlet channel, guided by the tilt structure of the valve cap to be flowed from the pressure cavity to the outlet valve structure, and then flowed out of the outlet channel.

Abstract: The piezoelectric pump comprises a housing, containing the following components connected in series: a rear piezoelectric clamp section, a piezoelectric extender section and a front piezoelectric clamp section. A displacer of pumped fluid is connected to the front piezoelectric clamp section. Electric pulses accessing at sections from a control station cause said sections to become fixed alternately inside the housing. Under the effect of electric pulses, the piezoelectric extender section moves the displacer step-by-step in one direction. Positive effect achieved by the invention is that of increasing the service life of the piezoelectric pump, expanding the scope of use thereof by increasing the number of fluids that can be pumped and also providing for a greater pressure by preventing contact between the pumped fluid and the friction surfaces of the housing and the piezoelectric clamp sections.

Abstract: A disc pump valve includes an elliptical pump base having at least one aperture extending through the base. The base comprises a first end wall and a sealing surface. The pump includes an isolator overlying the base and having an isolator valve aperture extending through the isolator at or near the periphery of the isolator and partially overlying a cavity formed by the base to form an outlet. In addition, the disc pump includes a valve flap disposed between the pump base and the isolator. The flap has apertures arranged about its periphery, beyond the periphery of the cavity but underlying an isolator valve aperture. The flap seals against the sealing surface to close the pump outlet and prevent fluid from flowing from the outlet into the cavity and flexes away from the sealing surface to allow fluid to pass from the cavity through the pump outlet.

Abstract: Methods and systems for applying charge to a piezoelectric element include and/or facilitate implementation of processes including cyclical multi-stage processes for: providing a piezoelectric element with an accumulated charge; providing one or more charge holding elements with a scavenged charge from the piezoelectric element; substantially removing or discharging a remaining charge from the piezoelectric element; and applying the scavenged charge to the piezoelectric element with an opposite polarity in relation to the polarity of the remaining charge.

Abstract: A piezoelectric pump includes a leaf spring including a disc portion defining an actuator, an outer frame portion defining a housing, and an elastic support portion. The actuator flexurally vibrates from a center portion of a principal surface thereof to an outer periphery thereof. The elastic support portion includes a beam portion and connection portions and elastically supports the disc portion on the outer frame portion. The beam portion extends in a gap between the disc portion and the outer frame portion in a direction along an outer periphery of the disc portion. A first of the connection portions connects the beam portion to the disc portion. Second and third connection portions are offset from the first connection portion and connect the beam portion to the outer frame portion.

Abstract: The invention relates to an ultrasonic traveling wave micropump for moving a liquid, said micropump comprising: two single linear piezoelectric transducers (2, 3); a flexible metal blade (4), each end portion of which rests on one of the two linear piezoelectric transducers; a sealable channel (5) that is made of shape-changing material and is intended for transporting the liquid from an inlet (E) to an outlet (S) of the micropump, said channel (5) resting longitudinally on said blade (4) between said linear piezoelectric transducers (2, 3); and an excitation means (7) for exciting at least the linear piezoelectric transducer (2) located near the inlet (E) of the micropump so that said transducer generates a transverse vibration in the blade (4) and the channel (5) along a traveling wave moving to the outlet (S) of the micropump.

Abstract: There is described a microvalve system having a first body portion having a fluid channel defined in a face, an electrode disposed in the fluid channel and electrically connectable to a power source, a channel membrane disposed over the fluid channel and aligned with the electrode, and a second body portion disposed on the first body portion, the first body portion comprising a liquid receiving cavity aligned with the membrane. The liquid receiving cavity is adapted to receive an electrical conducting liquid that is electrically connectable to the power source. The channel membrane is displaceable towards the electrode upon application of an electrical potential difference between the electrode and the electrical conducting liquid in order to at least partially obstruct the fluid channel.

Abstract: Piezoelectric pump for a household electric appliance having a moving wall interposed between a first casing element defining a pumping chamber with the moving wall, and a second casing element applying pressure to the periphery of the moving wall in order to hold the latter in position. The moving wall has an exterior face in contact with a piezoelectric actuator designed to cause the moving wall to move so as to bring about a periodic variation in the volume of the pumping chamber under the action of the piezoelectric actuator wherein the first casing element and the second casing element are held together under stress by an elastic clip, the elastic clip applying a pressure that tends to compress the first casing element onto the second casing element.

Abstract: A piezoelectric pump is capable of reliably discharging gas and reliably transporting liquid even when intermittently driven. The piezoelectric pump includes a piezoelectric vibrator, a diaphragm deflected and deformed by the piezoelectric vibrator, a pump chamber including at least one wall surface defined by the diaphragm, an inlet through which liquid, gas, or a mixture of liquid and gas flows into the pump chamber, an outlet through which the fluid is discharged, and a liquid holding member arranged to provide a gap between the liquid holding member and the inner surface of the pump chamber and to maintain the liquid in the gap using capillary effect or surface tension. A flow passage plate includes a flow passage groove provided therein.

Abstract: Provided is an ironing appliance, including a pump that has a pumping chamber provided with an inlet and an outlet, the pumping chamber including a moveable wall having an outer surface contacting a piezoelectric actuator provided to move the movable wall while changing the volume of the pumping chamber by the piezoelectric actuator, wherein the pump is placed in the ironing appliance such that the outlet of the pumping chamber is located at a higher level than the inlet in a normal position for operating the appliance.

Abstract: A micropump device including a first wafer and a second wafer attached to the first wafer. The first and second wafers are configured to define a chamber therebetween having a predetermined volume. A third wafer is attached to the second wafer to define an inlet section and an outlet section in fluid communication with the chamber. At least one of the second and third wafers are formed to define a moveable diaphragm configured to change the predetermined volume of the chamber for pumping a fluid between the inlet section and the outlet section.

Abstract: A piezoelectric micropump in which a pump chamber is isolated by a diaphragm. A piezoelectric element is disposed on a back surface of the diaphragm, and the diaphragm is deformed by bending deformation of the piezoelectric element to change the volume of the pump chamber and transport fluid in the pump chamber. A support member for supporting a back surface of the piezoelectric element is provided so that the support member inhibits bending of a peripheral portion of the diaphragm in a reverse direction. The support member thus prevents the piezoelectric element from being floated. Accordingly, the displacement of the piezoelectric element can be reliably transmitted as the change in volume of the pump chamber, thereby enhancing the fluid transportation performance.

Abstract: Control process for a piezoelectric pump (100) of an electric household appliance comprising a pump chamber (110) equipped with a mobile wall (111) displaceable under the action of a piezoelectric actuator (111A), characterized in that during a startup phase of the pump (100), the piezoelectric actuator (111A) is supplied during a plurality of alternations with an alternating supply signal having a voltage U bringing about a substantial deformation of the piezoelectric actuator (111A) for a maximum sweeping of the volume of the pump chamber (110) by the mobile wall (111), and further characterized in that the pump startup phase is followed by a normal operation phase during which the supply signal is modified so that the mean flow rate provided by the pump (100) is less than the flow rate provided during the startup phase.

Abstract: A fluid transporting device is provided with a pump chamber that has a pump function for sucking and discharging a fluid, and is filled therein with the fluid, a casing unit which forms one portion of a wall surface of the pump chamber, a diaphragm which is formed by a conductive polymer film that is subjected to electrochemomechanical expansion and contraction, and forms one portion of the wall surface of the pump chamber, an electrolyte chamber that contains an electrolyte therein, with one portion of the electrolyte being made in contact with the diaphragm, a power supply that applies a voltage to the diaphragm, and a pressure maintaining unit that maintains a pressure of the diaphragm within a predetermined range by moving or deforming the one portion of the wall surface of the electrolyte chamber.

Abstract: A piezoelectric actuator is provided, including a piezoelectric layer which is joined to a joining member and which has a coefficient of linear expansion smaller than a coefficient of linear expansion of the joining member; a first electrode which is arranged on one surface of the piezoelectric layer; a second electrode which is arranged on a portion of the one surface of the piezoelectric layer different from the first electrode and which is in conduction with the first electrode; and a low dielectric layer which is formed between the piezoelectric layer and the second electrode and which has a dielectric constant lower than a dielectric constant of the piezoelectric layer.

Abstract: A piezoelectric micro-blower includes a blower chamber located between a blower body and a vibrating plate, a first wall portion of the blower body arranged to face the vibrating plate across the blower chamber so as to vibrate with vibrations of the vibrating plate, a first opening in the first wall portion, a second wall portion on the opposite side of the first wall portion with respect to the blower chamber, a second opening in a portion of the second wall portion which faces the first opening, and an inflow passage located between the first wall portion and the second wall portion. Each of the first and second openings includes a plurality of holes, and each hole of the first opening and each hole of the second opening are arranged to face each other. Thus, noise is significantly reduced while the flow characteristic is maintained.

Abstract: A fluid control device includes a vibrating plate unit, a driver, and a flexible plate. The vibrating plate unit includes a vibrating plate including a first main surface and a second main surface, and a frame plate surrounding the surroundings of the vibrating plate. The driver is provided on the first main surface of the vibrating plate, and vibrates the vibrating plate. The flexible plate has a hole formed thereon. Furthermore, the flexible plate faces the second main surface of the vibrating plate, and adheres to the frame plate by the adhesive agent that contains a plurality of particles arranged such that the plurality of particles are interposed between the flexible plate and the vibrating plate.

Abstract: A fluid control device includes a vibrating plate unit, a driver, a flexible plate, and a base plate. The vibrating plate unit includes a vibrating plate including first and second main surfaces, and a frame plate surrounding the surrounding of the vibrating plate. The driver is bonded to the first or the second main surface of the vibrating plate and vibrates the vibrating plate. The flexible plate includes a hole provided therein, and is bonded to the frame plate so as to face the vibrating plate. The base plate is bonded to the main surface of the flexible plate on a side opposite to the vibrating plate. A size relationship between the coefficients of linear expansion of the material of the base plate and the frame plate is equal to a size relationship between the coefficients of linear expansion of the material of the vibrating plate and the driver.

Abstract: A fluid feeding pump which varies a volume of a pump chamber and thus feeds a fluid out of the pump chamber, includes: a piezoelectric element which accumulates electric charges inside when a voltage is applied, and which deforms according to an amount of accumulated electric charges and thus increases or decreases the volume of the pump chamber; a drive unit which applies a drive signal with a waveform increasing to a predetermined maximum voltage and then decreasing, and thus drives the piezoelectric element; and an air bubble determining unit which detects a current flowing through the piezoelectric element within a predetermined period after the drive signal is applied to the piezoelectric element, and thus determines whether there are air bubbles in the pump chamber or not.

Abstract: Disclosed is a piezoelectric pump. The piezoelectric pump includes a pump body, a drive unit, a detection section, and a control unit. The pump body includes a hole for introducing a fluid from outside thereinto and jetting the fluid from inside, a wall portion disposed so as to face the hole, and a piezoelectric body provided on the wall portion to vibrate the wall portion. The drive unit drives the piezoelectric body. The detection section detects a signal corresponding to a discharge rate of the fluid from the hole. The control unit controls a drive voltage and a drive frequency of the drive unit on the basis of the signal.

Abstract: A pump arrangement includes a pump having a pump inlet and a pump outlet, and a safety valve arranged between the pump outlet and an outlet of the pump arrangement and having a valve seat and a valve lid. The valve seat, the pump outlet and the pump inlet are patterned in a first surface of a first integrated part of the pump arrangement, whereas the valve lid is formed in a second integrated part of the pump arrangement. An inlet of the pump arrangement and a fluid region fluidically connected thereto are formed in a third part of the pump arrangement. The second integrated part is arranged between the first integrated part and the third part of the pump arrangement such that a pressure in the fluid region has a closing effect on the safety valve, the pump inlet and the inlet of the pump arrangement being connected fluidically.

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 a valve for controlling the flow of fluid through the valve.

Abstract: Provided is a micro fluidic transportation device capable of controlling discontinuous transportation of micro droplets using surface acoustic wave (SAW), and a method for manufacturing the same. The micro fluidic transportation device which includes: a substrate; a piezoelectric layer formed on the substrate; an inter digitated transducer (IDT) electrode formed on the piezoelectric layer for energy conversion by generating a surface acoustic wave (SAW); and a fluid passage formed on the piezoelectric thin layer.

Abstract: A microfluidic device is described. The microfluidic device comprises at least one transport channel and at least one working chamber, wherein the at least one transport channel and the at least one working chamber are separated from each other by a common deformable wall. The at least one transport channel is for containing a transport fluid and the at least one working chamber is for containing a working fluid. The microfluidic device comprises at least one pair of electrodes for changing the pressure on the working fluid such that when the pressure on the working fluid is changed, the deformable wall deforms, resulting in a change of the cross-section of the at least one transport channel. The working chamber comprises a flexible wall different from the common deformable wall and at least one electrode of the at least one pair of electrodes is provided on the flexible wall.

Abstract: A drive waveform signal as a reference of a drive signal to be applied to a piezoelectric element is power-amplified, and the drive signal after passing through a coil is applied to the piezoelectric element. A resonant circuit is formed of the coil and the piezoelectric element, and a resonant peak is suppressed by performing a phase advance compensation of the drive signal and by performing a negative feedback. At this time, the degree of suppression of the peak is adjusted so that a slight reverse voltage is generated. Since this can eliminate residual distortion of the piezoelectric element by the reverse voltage, even when driving is performed at a high repetition frequency, the original amount of deformation can be ensured. Besides, the circuit does not become complicated.

Abstract: Systems, devices and methods are provided, for acquiring and dispensing predetermined volumes of liquids and, in particular, to a unique piezoelectric dispenser for acquiring and dispensing of small volumes of fluid in an automatic or manual production of DNA arrays and assays, wherein droplets are dispensed in a single drop format with volumes that may range from about a few picoliters to several nanoliters. The dispenser can advantageously utilize a disposable capillary tube assembly while desirably retaining the piezoelectric actuator for subsequent further uses, thereby mitigating the possibility of cross contamination of fluids and providing an economical and cost effective approach with reuse of the piezoelectric actuator for further operation such as with a variety of liquids to be dispensed and transferred. A unique longitudinal transducer can transmit radial tube displacement into controlled axial motion of the tube.

Abstract: There is provided a piezoelectric type cooling device including: a housing having an internal space formed by combining an upper housing and a lower housing and having openings allowing the internal space to be in communication with the atmosphere to allow air to be introduced thereinto and discharged therefrom; a diaphragm provided to traverse the internal space of the housing to divide the internal space into upper and lower blower chambers; and a piezoelectric actuator provided on at least one surface of the diaphragm to provide vertical driving force to the diaphragm.

Abstract: A pump chamber (15) is formed between a piezoelectric vibrator (7) and a valve main plate (10). The valve main plate (10) includes an inlet port (13) at its central portion, and an outlet port (14) in its peripheral portion, and the inlet port (13) is made in a smaller diameter than the outlet port (14). On the valve main plate (10) an inflow check valve (11) and an outflow check valve (12) are provided, so that when the inflow check valve (11) and the outflow check valve (12) open and close in response to the vibration of the piezoelectric vibrator (7), a fluid is introduced into and discharged from the pump chamber (15).

Abstract: A fluid conveyance device includes a substrate, and a disk-shaped piezoelectric element arranged in a bendable manner on the substrate. A plurality of substantially circular concentric segment electrodes are provided on the piezoelectric element, and are provided with voltages with phases that are shifted. A wavy ring deformation is thus produced on the piezoelectric element. A pocket produced between the piezoelectric element and the substrate is moved in a radial direction so as to convey a fluid from an outer substantially circular portion to a central portion and to discharge the fluid from the central portion.

Abstract: A valveless MEMS micropump capable of improved efficiency and performance is disclosed. The micropump includes two adjoining chambers separated by a piezoelectric actuated pump membrane. The micropump moves fluid through the chambers through diffuser elements characterized by differential directional resistance to fluid flow by piezoelectric actuation of the pump membrane.

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 fluid conveyance device includes a substrate, and a disk-shaped piezoelectric element arranged in a bendable manner on the substrate. A plurality of substantially circular concentric segment electrodes are provided on the piezoelectric element, and are provided with voltages with phases that are shifted. A wavy ring deformation is thus produced on the piezoelectric element. A pocket produced between the piezoelectric element and the substrate is moved in a radial direction so as to convey a fluid from an outer substantially circular portion to a central portion and to discharge the fluid from the central portion.

Abstract: A micropump in the form of a stack comprising, in succession, a flexible diaphragm, a pumping chamber and a closing-off plate, said pumping chamber communicating with the outside, for example via the flexible diaphragm; said diaphragm being furthermore secured to an actuator arranged outside the micropump, characterized in that said diaphragm is secured to the actuator by way of at least one element in the form of a strip, which is rigid along its main axis and flexible in the direction perpendicular to its main axis.

Abstract: A piezoelectric pump for pumping a fluid at a high flow rate includes a housing and an actuator located within the housing. An electric voltage applied to the actuator causes the actuator to apply a force to a first diaphragm that is proximate to the actuator. A piston assembly is located within the housing and is moveable between at least a first position and a second position. A first fluid chamber is defined by the housing, the first diaphragm, and the piston assembly. A coupling fluid is located within the first fluid chamber for coupling the first diaphragm to the piston assembly. A second fluid chamber is defined by the housing and the piston assembly. An inlet valve is in communication with the second fluid chamber and an outlet valve is in communication with the second fluid chamber.

Abstract: A liquid cooling apparatus for cooling an inversely mounted electronic component, includes a casing defining a receiving room therein, a diaphragm, a partition plate forming a nozzle thereon, and a piezoelectric element attached to the diaphragm in such a manner that a vibrating direction thereof is perpendicular to the diaphragm. The diaphragm is arranged in the receiving room and divides the receiving room into a top first chamber and a bottom second chamber isolated from each other. The partition plate is arranged in the first chamber and divides the first chamber into an upper region and a lower region. The lower region is filled with a working fluid. When the diaphragm is driven to vibrate upwardly by the piezoelectric element, the diaphragm pushes the working fluid in the lower region of the first chamber to the upper region of the first chamber via the nozzle.

Abstract: In a piezoelectric micro-blower, a vibration plate assembly includes a piezoelectric element attached to a diaphragm, with an intermediate plate interposed there between. A blower chamber plate includes a circular opening in a center thereof. A blower chamber defined by the diaphragm, a flow path plate, and the opening of the blower chamber plate is sized to allow internal pressure to be substantially uniformly changed by vibration of the diaphragm. The blower chamber plate and the flow path plate are provided with a first outlet and a second outlet, respectively. Compressive fluid pressurized in the blower chamber is blown out through the first and second outlets.

Abstract: A cooling device (1) using pulsating fluid for cooling of an object, comprising: a transducer (2) having a membrane adapted to generate pressure waves at a working frequency (fw), and a cavity (4) enclosing a first side of the membrane. The cavity (4) has at least one opening (5) adapted to emit a pulsating net output fluid flow towards the object, wherein the opening (5) is in communication with a second side of the membrane. The cavity (4) is sufficiently small to prevent fluid in the cavity (4) from acting as a spring in a resonating mass-spring system in the working range. This is advantageous as a volume velocity (u1) at the opening is essentially equal to a volume velocity (u1?) at the second side of the membrane, apart from a minus sign. Thus, at the working frequency the pulsating net output fluid can be largely cancelled due to the counter phase with the pressure waves on the second side of the membrane resulting in a close to zero far-field volume velocity.

Abstract: A small-sized, low-profile fluid pump having high pumping capabilities includes an actuator and a planar section including a metal plate. The actuator includes a disk-shaped piezoelectric element attached to a disk-shaped diaphragm. As a result of application of a square-wave or sine-wave drive voltage, the actuator performs a bending vibration from the central portion to the peripheral portion. The peripheral portion of the actuator is not restrained. The actuator performs a bending vibration in the state in which it is in proximity to the planar section while facing the planar section. A center vent is provided at or in an area adjacent to the center of an actuator facing area of the planar section that faces the actuator.

Abstract: A piezoelectric pump includes a diaphragm that defines a pump chamber between the diaphragm and a pump body, and a piezoelectric element bonded to a surface of the diaphragm. The piezoelectric element is a bimorph piezoelectric element in which a plurality of piezoelectric layers are stacked, including a neutral layer disposed in the approximate middle of the piezoelectric element in the thickness direction and that is not displaced. The piezoelectric element can be efficiently displaced because a neutral plane of the diaphragm and the piezoelectric element bonded therein is located in the neutral layer.

Abstract: A microfluidic system includes a bubble valve for regulating fluid flow through a microchannel. The bubble valve includes a fluid meniscus interfacing the microchannel interior and an actuator for deflecting the membrane into the microchannel interior to regulate fluid flow. The actuator generates a gas bubble in a liquid in the microchannel when a sufficient pressure is generated on the membrane.

Abstract: A channel is formed as an asymmetric diffuser-shaped channel having a narrow channel on a diffuser inlet side and a wide channel on a diffuser outlet side. The narrow channel is communicated with a variable volume chamber which is provided therein with a piezoelectric element. Vibration generated by actuation of the piezoelectric element causes a pressure variation of a fluid in the variable volume chamber to generate a nozzle flow which in turn causes a smooth flow of the fluid from the wide channel to the narrow channel.

Abstract: An electrical connection structure for use in a micro piezoelectric pump is disclosed. The electrical connection structure includes a driving circuit board and a multilayered wiring structure. The electrical connection structure includes the driving circuit board, the wiring structure, and a piezoelectric element arranged from top to bottom. The driving circuit board is provided with a driving circuit for driving the piezoelectric element and at least an electrical contact, wherein the electrical contacts are electrically connected to the driving circuit. A first electrode contact region and a second electrode contact region electrically insulated from each other are defined on the same surface of the piezoelectric element. The wiring structure sends a signal from the electrical contacts to the first electrode contact region and the second electrode contact region.

Abstract: A piezoelectric pump includes a pump body with a pump chamber, and a piezoelectric element that closes the pump chamber. The central area and the peripheral area of the piezoelectric element are bent in opposite directions by applying voltages to the piezoelectric element so that the volume of the pump chamber is changed. The piezoelectric element is a laminate including a plurality of piezoelectric layers with electrodes interposed therebetween. The central area and the peripheral area of each piezoelectric layer are polarized opposite to each other in the thickness direction, and the electrodes are formed such that voltages in the same direction in the thickness direction are applied to the central area and the peripheral area of each piezoelectric layer. Since voltages at the same potential are applied to the electrodes formed in the same planes of the piezoelectric layers, short-circuits caused by migration can be prevented.

Abstract: A pump using a piezoelectric diaphragm is designed to allow the diaphragm to be supported appropriately and accurately and to facilitate assembly of housing members. The peripheral edge of a sheet metal of a unimorph diaphragm 40 on the side thereof facing a first housing member 14 is pressed and supported with the ridge of an annular projection 52 annularly provided along the peripheral edge of a vent chamber 38. The first to third housing members 14, 16 and 30 are stacked on one another, and the first and third housing members 14 and 30 are welded together by ultrasonic welding such that the first and second housing members 14 and 16 abut against each other at abutting portions 66 and 68 and the second and third housing members 16 and 30 abut against each other at abutting portions 70 and 72, thereby definitely determining the positional relationship between the housing members.

Abstract: A self-contained pump is disclosed that is an integrated pump. It has a reservoir, a pumping mechanism, and at least one outlet. The pumping mechanism is for controlled compression of the reservoir to force a required volume of fluid in the reservoir through the at least one outlet.

Abstract: Provided are a micropump that makes it possible to reduce the entire size and improve pumping performance of fluid, and a method of operating the micropump. The micropump includes a case that forms a first space and a second space that are connected through a connection channel, a fluid intake pipe that is connected to the first space, a fluid discharge pipe that is connected to the second space, a first deforming member that is disposed on the case to cover the first space, and a second deforming member that is disposed on the case to cover the second space. The second deforming member is formed larger than the first deforming member and the maximum displacement of the second deforming member is larger than the maximum displacement of the first deforming member.

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 disposable fluid contacting portion which defines a fluid inlet and outlet and a fluid path there between. The pump includes a drive portion configured to engage the disposable portion to cause fluid to be moved from the fluid inlet to the fluid outlet. The disposable portion is configured to be selectively coupled to the drive portion. The disposable portion includes a driven membrane which forms a portion of the fluid path, and the drive portion includes a drive membrane. The two membranes are vacuum coupled to each other, whereby movement of the drive membrane causes the driven membrane to move, causing fluid to be pumped through the disposable portion. The pump has particular utility in the medical field for moving fluid from a source to a patient. The pump may include features such as an air-trap, bubble detection, fluid flow controls, and pressure detection.