Patent US3819250A successfully refreshed from Google Patents.
US3857049A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pulsed droplet ejecting system
Assignee: Gould Inc
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Filing: 1973-10-12
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Granted: 1974-12-24
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Expires: 1993-10-12
Abstract
Abstract An electro-acoustic transducer is coupled to liquid in a conduit which terminates in a small orifice adjacent to the transducer. Preferably, the acoustic impedance of the supply portion of the conduit is large compared with the acoustic impedance of the orifice. The liquid is under small or zero static pressure. Surface tension at the orifice prevents liquid flow when the transducer is not actuated. An electrical pulse with short rise time causes sudden volume change at the transducer, thereby creating an acoustic pressure pulse having sufficient amplitude to overcome the surface tension at the orifice and eject a small quantity of liquid therefrom. Thereafter, the pulse decays slowly, holding the rate of change of volume low enough so that the resulting pressure decrease is not sufficient to overcome the surface tension. Consequently, liquid flows from the supply portion of the orifice into the transducer to replace the liquid previously ejected, without drawing in air through the orifice.
Inventors
- 👤 S Zoltan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 11:04
CPC Classifications
B; B41; B41J; B41J2/00; B41J2/005; B41J2/01; B41J2/015; B41J2/04; B41J2/045; B41J2/04501; B41J2/04541; B41J2/04581; B41J2/04593; H; H04; H04R; H04R17/00; H04R17/04; H04R17/08
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
257 words
A system adapted upon pulsing to expel a small quantity or a succession of small quantities of liquid in controlled manner, comprising: a reservoir containing said liquid; a conduit connected to said reservoir and communicating with the liquid therein and filled with said liquid under small or zero static pressure, said conduit having an exit orifice which is sufficiently small that surface tension in the absence of pulsing prevents said liquid from flowing therefrom; a platelike piezoelectric transducer having two opposed major faces, and housing means sealed around the periphery of said transducer, said housing means forming a portion of said conduit with said ceramic transducer therein coupled to said liquid substantially only at the periphery of said transducer, substantially the full areas of said major faces of said transducer being free of coupling to said liquid, said transducer being adapted to expand parallel to said major faces to displace a small quantity of said liquids overcoming said surface tension to expel a small quantity of said liquid through said orifice and to contract prior to a subsequent expansion; electrical circuit means connected to said transducer for applying thereto an electrical pulse of a given polarity to cause said transducer to expand and upon decay of said pulse to allow said transducer to contract; said conduit during operation of said system at all times being open from said reservoir to said orifice whereby the liquid within said housing is replaced by liquid from said reservoir to make up for said expelled liquid upon termination of said pulse.
Claim 2
Independent Claim
257 words
A system adapted upon pulsing to expel a small quantity or a succession of small quantities of liquid in controlled manner, comprising: a reservoir containing said liquid; a conduit connected to said reservoir and communicating with the liquid therein and filled with said liquid under small or zero static pressure, said conduit having an exit orifice which is sufficiently small that surface tension in the absence of pulsing prevents said liquid from flowing therefrom; a platelike piezoelectric transducer having two opposed major faces, and housing means sealed around the periphery of said transducer, said housing means forming a portion of said conduit with said ceramic transducer therein coupled to said liquid substantially only at the periphery of said transducer, substantially the full areas of said major faces of said transducer being free of coupling to said liquid, said transducer being adapted to expand parallel to said major faces to displace a small quantity of said liquids overcoming said surface tension to expel a small quantity of said liquid through said orifice and to contract prior to a subsequent expansion; electrical circuit means connected to said transducer for applying thereto an electrical pulse of a given polarity to cause said transducer to expand and upon decay of said pulse to allow said transducer to contract; said conduit during operation of said system at all times being open from said reservoir to said orifice whereby the liquid within said housing is replaced by liquid from said reservoir to make up for said expelled liquid upon termination of said pulse.
Claim 3
Dependent Claim
29 words
A system as described in claim 1 in which said transducer is a piezoelectric ceramic transducer, said major faces are circular, and said transducer is adapted to expand radially.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-12-23 | 1978-06-24 | 1978-12-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-23 | 1982-06-24 | 1982-12-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-23 | 1986-06-24 | 1986-12-24 | $7700.00 | Window Closed / Lapsed |