A liquid material ejection device in which a plunger is efficiently accelerated. The device includes a liquid chamber communicating with an ejection port and being supplied with a liquid material, a plunger including a tip portion having a smaller diameter than the liquid chamber and is moved in the liquid chamber, an elastic member urging the plunger upward, an arm disposed in a state extending in a substantially horizontal direction, an arm driver serving as a driving source to operate the arm, and a base member on which the arm driver is disposed. The device further includes a rocking mechanism unit connected to the arm driver and rockingly supporting the arm, the arm driver includes a plurality of actuators, the arm includes a pressing portion pressing the plunger downward, the plunger is pressed by the pressing portion, and the plunger is linearly reciprocated with rocking motion of the arm.

A power driver of an unmanned aerial vehicle is disclosed and includes a main body, a fluid actuation system and a controller, wherein the fluid actuation system includes a driving zone, a converging chamber, a plurality of valves and a fluid discharging zone. The driving zone includes a plurality of flow guiding units which arranged in series, parallel or series-parallel, each of the flow guiding unit generates an inside pressure gradient after being actuated, so as to inhale fluid and diverge fluid by guiding channels, and flow into the convergence chamber for storage, wherein the amount of the fluid transported is controlled by the plurality of valves disposed in the connection channels through the controller, and fluid is finally converged to the fluid discharging zone for discharging the specific transportation amount of fluid.

A fluid control device includes a piezoelectric pump, a piezoelectric pump, a container, and a control unit. The piezoelectric pumps and are connected in series. The piezoelectric pump is an upstream-side pump, and the piezoelectric pump is a downstream-side pump. The control unit controls driving of the piezoelectric pumps. The control unit makes the driving start timing of the piezoelectric pump on an upstream side earlier than the driving start timing of the piezoelectric pump on a downstream side.

A fluid end assembly comprising a plurality of fluid end sections positioned in a side-by-side relationship. Each fluid end section comprises a housing made of multiple-piece construction. One or more pieces of the housing are configured to have a plurality of stay rods attached thereto. The stay rods interconnect the fluid end assembly and a power end assembly.

A method for altering one or more properties of a dielectric fluid for use in an electrohydrodynamic, EHD, thermal management system (100), as well as the system, are provided. The system comprises at least one EHD pump unit (110) comprising at least two electrodes for pumping the dielectric fluid and at least one enclosure (120) for accommodating the fluid within the system. The method comprises exposing the dielectric fluid to an ionizing process (122) configured to ionize the dielectric fluid, and operating the pump unit to circulate the exposed fluid in the enclosure.

A method for altering one or more properties of a dielectric fluid for use in an electrohydrodynamic, EHD, thermal management system (100), as well as the system, are provided. The system comprises at least one EHD pump unit (110) comprising at least two electrodes for pumping the dielectric fluid and at least one enclosure (120) for accommodating the fluid within the system. The method comprises exposing the dielectric fluid to an ionizing process (122) configured to ionize the dielectric fluid, and operating the pump unit to circulate the exposed fluid in the enclosure.

A high pressure pump. The pump comprises a fluid end assembly supported on a power end assembly. The power end assembly is modular and held together by a first set of stay rods. The fluid end assembly comprises a plurality of fluid end sections positioned in a side-by-side relationship. Each fluid end section comprises a housing made of multiple-piece construction. One or more pieces of the housing are configured to having a second set of stay rods attached thereto. The second set of stay rods interconnect the fluid end assembly and a power end assembly and a vertically offset from the first set of stay rods.

A pump includes a cylinder having a lower end formed with a suction pipe; an inlet section including a housing, a lower externally threaded section, an upper externally threaded section, an upper nut secured to the upper externally threaded section, and an inlet having a valve, a first connector having one end connected to the valve, and a second connector having a connection element connected to the valve, a hollow projection opposite to the connection element and provided through the housing, and an axial hole through the hollow projection; a joining section secured to the cylinder and including a hollow first externally threaded section, a hollow second externally threaded section, and a hollow first internally threaded section secured to the second externally threaded section; a manual operation section including a piston rod extending downward from a spring biased handle into the cylinder; and an outlet section.

A piezoelectric element drive circuit includes a piezoelectric element driven at a predetermined frequency and having a resonant frequency of (2n+1) times the predetermined frequency (n is a predetermined natural number), and a drive voltage generator that has a first output terminal connected to a first terminal of the piezoelectric element and a second output terminal connected to a second terminal of the piezoelectric element. When the piezoelectric element is driven, a waveform of potential difference between the first output terminal and the second output terminal is a step wave which transitions while taking an intermediate potential. A time length for which the potential difference is the intermediate potential is around (t2−t1)/(2n+1) in a period of time from time t.sub.1 at which the potential difference falls to the intermediate potential to time t.sub.2 at which the potential difference falls to the intermediate potential subsequently.

Systems to drive a downhole pump include an enclosure body with a magnetically transparent wall. A magnetic driver or a stationary member with coil windings in slots is disposed outside the enclosure body. A magnetic follower or a movable member with one or more permanent magnets is disposed inside the enclosure body such that the magnetic follower or movable member is exposed to a different environment compared to the magnetic driver or stationary member. The magnetic driver and magnetic follower, or the stationary member and movable member, are separated by a gap containing at least a portion of the magnetically transparent wall. A prime mover is operatively coupled to the magnetic driver. A rod couples the magnetic follower or the movable member to the downhole pump. Movement of the rod with the magnetic follower or the movable member operates the pump.