A miniature fluid control device includes a piezoelectric actuator, a gas collecting plate and a base. The piezoelectric actuator includes a suspension plate, an outer frame, at least one bracket and a piezoelectric ceramic plate. The suspension plate is a square plate. The outer frame is arranged around the suspension plate. A surface of the outer frame and a surface of the suspension plate are coplanar with each other. The gas collecting plate is a frame body with an accommodation space. The base includes a gas inlet plate and a resonance plate. The base is disposed within the accommodation space to seal the piezoelectric actuator. An adhesive layer is arranged between the second surface of the outer frame of the piezoelectric actuator and the resonance plate. Consequently, a depth of a compressible chamber between the piezoelectric actuator and the resonance plate is maintained.

A miniature pneumatic device includes a miniature fluid control device and a miniature valve device. The miniature fluid control device includes a gas inlet plate, a resonance plate, a piezoelectric actuator and a gas collecting plate. A first chamber is formed between the resonance plate and the piezoelectric actuator. After a gas is fed into the gas inlet plate, the gas is transferred to the first chamber through the resonance plate and then transferred. Consequently, a pressure gradient is generated to continuously push the gas. The miniature valve device includes a valve film and a gas outlet plate. After the gas is transferred from the miniature fluid control device to the miniature valve device, the valve opening of the valve film is correspondingly opened or closed and the gas is transferred in one direction. Consequently, a pressure-collecting operation or a pressure-releasing operation is selectively performed.

The present invention relates to a fuel pump for pumping fuel, comprising a piston (2) and a diaphragm seal element (3), which seals on an inner annular seal seat (4) and an outer annular seal seat (5), wherein the following equation is satisfied: (Ra.sup.2ra.sup.2)/(ri+L).sup.2=ra/ri, where ri is the inner radius of the inner seal seat (4), ra is the inner radius of the outer seal seat (5), Ra is the outer diameter of the piston (2) and L is a difference between an outer radius (Ria) of the inner seal seat (4) and the inner radius (ri) of the inner seal seat (4). The invention further relates to a method for operating a fuel pump.

A flow control device comprises a laminate structure of an electroactive material layer and a non-actuatable layer. An array of orifices is formed in one of the layers wherein the orifices are open in one of the rest state and actuated state and the orifices are closed in the other of the rest state and actuated state. Actuation of the electroactive material layer causes orifices to open and close so that flow control function may be implemented.

An object of the present invention is to provide a pump device that is capable of improving a discharge performance. A first orifice 301 that is provided on a discharge oil passage (a pipe 12) of a pump 2 and a second orifice 302 that, when a flow amount Q becomes greater than a predetermined flow amount Q1, allows pass of brake fluid are provided.

A rapid-discharge-valve structural body (2) allows air to flow from an input-side space (9A) to an output-side space (9B) in accordance with the flow rate of air to be supplied to a supply passage (101). Accordingly, the flow rate of air to be discharged from a discharge passage (113) also changes. As a consequence, flow rate peaking can be prevented.

A diaphragm pump has at least one pump chamber, the pump chamber being connected to an inlet chamber via an inlet valve and to an outlet chamber via an outlet valve. The inlet valve has an inlet opening which can be closed by an inlet valve body, and the outlet valve has an outlet opening which can be closed by an outlet valve body. The outlet opening surrounds the inlet opening, or the inlet opening surrounds the outlet opening.

A miniature pneumatic device includes a miniature fluid control device and a miniature valve device. The miniature fluid control device includes a gas inlet plate, a resonance plate, a piezoelectric actuator and a gas collecting plate. The length and width of the gas collecting plate are between 4 mm and 10 mm. A first chamber is formed between the resonance plate and the piezoelectric actuator. After a gas is fed into the gas inlet plate, the gas is transferred to the first chamber through the resonance plate and then transferred downwardly. Consequently, a pressure gradient is generated to continuously push the gas. The miniature valve device includes a valve film and a gas outlet plate. After the gas is transferred from the miniature fluid control device to the miniature valve device, the valve opening of the valve film is correspondingly opened or closed and the gas is transferred in one direction.

A miniature pneumatic device includes a miniature fluid control device and a miniature valve device. The miniature fluid control device includes a gas inlet plate, a resonance plate, a piezoelectric actuator and a gas collecting plate. A first chamber is formed between the resonance plate and the piezoelectric actuator. After a gas is fed into the gas inlet plate, the gas is transferred to the first chamber through the resonance plate and then transferred. Consequently, a pressure gradient is generated to continuously push the gas. The miniature valve device includes a valve film and a gas outlet plate. After the gas is transferred from the miniature fluid control device to the miniature valve device, the valve opening of the valve film is correspondingly opened or closed and the gas is transferred in one direction. Consequently, a pressure-collecting operation or a pressure-releasing operation is selectively performed.

A miniature fluid control device includes a piezoelectric actuator, a gas collecting plate and a base. The piezoelectric actuator includes a suspension plate, an outer frame, at least one bracket and a piezoelectric ceramic plate. The suspension plate is a square plate. The outer frame is arranged around the suspension plate. A surface of the outer frame and a surface of the suspension plate are coplanar with each other. The gas collecting plate is a frame body with an accommodation space. The base includes a gas inlet plate and a resonance plate. The base is disposed within the accommodation space to seal the piezoelectric actuator. An adhesive layer is arranged between the second surface of the outer frame of the piezoelectric actuator and the resonance plate. Consequently, a depth of a compressible chamber between the piezoelectric actuator and the resonance plate is maintained.