Apparatus for driving piezoelectric element for closing and opening valve member
First Claim
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1. An apparatus for driving a piezoelectric element to transmit a displacement of said piezoelectric element via a liquid to a valve member, for closing and opening said valve member, comprising:
- a high DC voltage generating means;
a charging switching means, connected to said high DC voltage generating means and said piezoelectric element, for generating a first voltage and applying said first voltage to said piezoelectric element for a predetermined time so that said valve member reaches a position near to a valve seat, and thereafter, increasing a voltage applied to said piezoelectric element from said first voltage to a second voltage higher than said first voltage so that said valve member is seated on said valve seat, to thereby close said valve; and
a discharging switching means, connected to said piezoelectric element, for discharging charges stored in said piezoelectric element to open said valve.
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Abstract
In an apparatus for driving a piezoelectric element used for closing and opening a valve member, a first-step voltage is applied to the piezoelectric element to move the valve element near to a valve seat, and thereafter, a second-step voltage higher than the first-step voltage is applied to the piezoelectric element to seat the valve element securely on the valve seat.
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Citations
14 Claims
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1. An apparatus for driving a piezoelectric element to transmit a displacement of said piezoelectric element via a liquid to a valve member, for closing and opening said valve member, comprising:
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a high DC voltage generating means;
a charging switching means, connected to said high DC voltage generating means and said piezoelectric element, for generating a first voltage and applying said first voltage to said piezoelectric element for a predetermined time so that said valve member reaches a position near to a valve seat, and thereafter, increasing a voltage applied to said piezoelectric element from said first voltage to a second voltage higher than said first voltage so that said valve member is seated on said valve seat, to thereby close said valve; anda discharging switching means, connected to said piezoelectric element, for discharging charges stored in said piezoelectric element to open said valve. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 13, 14)
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11. An apparatus as set forth in clam 10, wherein said charging switching means comprises:
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a first charging thyristor and a first coil connected in series between said first condenser and said piezoelectric element; and a second charging thyristor and a second coil connected in series between said second condenser and said piezoelectric element, an LC oscillation circuit being formed by said first condenser, said first coil, and said piezoelectric element, to generate said first voltage, when said first charging thyristor is turned ON by a first closing signal, an LC oscillation circuit being formed by said second condenser, said second coil, and said piezoelectric element, to generate said second voltage, when said second charging thyristor is turned ON by a second closing signal. - View Dependent Claims (12)
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Specification