摘要 |
A piezo-electrically actuated fluid control valve (10) has a nozzle type seat (18), a magnet (22) opposite from the seat (18), and a piezo-electric actuator (20) in sheet form between the seat (18) and magnet (22). The actuator (20) includes a piezo-ceramic layer (50) laminated to an electrode sheet (48), so that the composite is parallel to the seat (18) and a surface of the magnet (22). The electrode sheet (20) has opposite edges (20A, 20B) which extent beyond the piezo-ceramic layer (51) and are clamped by the housing (12) of the valve (10) so that the center of the actuator (20) is positioned between the seat (18) and magnet (22). When an electric field is applied to the piezo-ceramic layer (50), the actuator (20) bows or dishes so as to displace from the seat (18) toward the magnet (22), and the magnetic field of the magnet (22) draws the actuator (20) further away from the seat (18), to increase the valve opening between the actuator (20) and the seat (18). The actuator (20) may be operated by a pulse width modulated or a proportional analog electrical signal, which may be applied in combination with the magnetic field to move the actuator (20), or if the magnetic field is induced by an electromagnet (22), electrical and magnetic control modes may be used alternatively. |