Central bolt ultrasonic atomizer

Claim 2

An ultrasonic liquid atomizing transducer assembly comprising: a driving element including a pair of annular piezoelectric disks and an annular electrode coaxially positioned therebetween; terminal means for feeding ultrasonic frequency electrical energy to said electrode; a cylindrical rear dummy section having a front end contacting one piezoelectric disk of the driving element, a rear end, and a constant outside diameter from the front end to the rear end; a front section having a cylindrical portion, the cylindrical portion having a rear end contacting the other piezoelectric disk of the driving element and a front end, and an amplifying portion extending from the front end of the cylindrical portion, the amplifying portion comprising a probe having a tip that forms an atomizing surface, an axial passage being provided through the length of the transducer assembly from the rear end of the rear dummy section to the atomizing surface, and a portion of the passage adjacent the driving element in both the front atomizing section and the rear dummy section being enlarged and internally threaded; a tubular central bolt having an externally threaded portion engaging said internally threaded portion of the passage in both the front atomizing section and the rear dummy section with sufficient torque to connect the front atomizing section and the rear dummy section under a tension that provides all of a predetermined total compressive preload on the driving element, the externally threaded portion extending from a front end portion of the bolt located in the front atomizing section and formed with a smooth cylindrical sealing surface to a rear feed tube portion of the bolt located in the rear dummy section and extending axially beyond the rear end of the dummy section; and means for sealing the piezoelectric disks from contact with the liquid being atomized, said means comprising a resilient annular sealing member disposed between said sealing surface and the axial passage in the front section to prevent liquid flowing in the pasasge from reaching the inner circumferential surfaces of the piezoelectric disks.

Claim 3

An atomizing transducer assembly according to claim 1 wherein the annular sealing member comprises an O-ring.

Claim 4

An atomizing transducer assembly according to claim 1 wherein the means for sealing the piezoelectric disks comprises an additional annular sealing member disposed between the smooth exterior surface of said liquid feed tube and the axial passage to prevent moisture in the environment surrounding the transducer assembly from reaching the inner circumferential surfaces of the piezoelectric disks.

Claim 5

An atomizing transducer assembly according to claim 3 wherein the additional annular sealing member comprises an O-ring.

Claim 6

An atomizing transducer assembly comprising: a driving element including a pair of annular piezoelectric disks and an annular electrode coaxially positioned therebetween; terminal means for feeding ultrasonic frequency electrical energy to said electrode; a cylindrical rear dummy section having a front face contacting one piezoelectric disk of the driving element, a rear face, the dummy section having a constant outside diameter from the front face to the rear face, and a concentric portion having a smooth cylindrical outer sealing surface of reduced diameter extending from said rear face; a front section having a cylindrical portion, the cylindrical portion having a rear face contacting the other piezoelectric disk of the driving element and a front face, and an amplifying portion extending from the front face of the cylindrical portion, the amplifying portion comprising a probe having a tip that forms an atomizing surface, an axial passage being provided through the length of the transducer assembly from the rear face of the rear dummy section to the atomizing surface, and a portion of the passage adjacent the driving element in both the front atomizing section and the rear dummy section being enlarged and internally threaded; a tubular central bolt having an externally threaded portion engaging said internally threaded portion of the passage in both the front atomizing section and the rear dummy section with sufficient torque to connect the front atomizing section and the rear dummy section under a tension that provides all of a predetermined total compressive preload on the driving element, the externally threaded portion extending from a front end portion of the bolt located in the front atomizing section and formed with a smooth cylindrical sealing surface to a rear feed tube portion of the bolt located in the rear dummy section and extending axially beyond the rear end of the dummy section; and means for sealing the piezoelectric disks from contact with the liquid being atomized, said means comprising a resilient first annular sealing member disposed between said sealing surface and the axial passage in the front section, to prevent liquid flowing in the passage from reaching the inner circumferential surfaces of the piezoelectric disks, and an enclosed circular cylindrical shell surrounding the transducer assembly, the cylindrical shell having a front end wall provided with a first cylindrical passage that loosely receives the cylindrical portion of the front section, a rear wall provided with a second cylindrical passage that loosely surrounds the concentric portion extending from the rear face of the dummy section, a resilient second annular sealing means disposed between the inner surface of the first cylindrical passage and the circumference of the cylindrical portion of the front section, and a resilient third annular sealing means disposed between the inner surface of the second cylindrical passage and the outer sealing surface of the concentric portion, the radial spacing between the cylindrical portion of the front section and the first cylindrical passage and the radial spacing between the concentric portion of the rear dummy section and the second cylindrical passage being respectively less than the radial thicknesses of the second and the third annular sealing means when unconstrained, so that the second and third annular sealing means are radially compressed between said passages and said cylindrical and concentric portions, respectively, and wherein said first and second annular sealing means are unconstrained in the axial direction, with no axial pressure exerted thereon.

Claim 7

An atomizing transducer assembly comprising: a driving element including a pair of annular piezoelectric disks and an annular electrode coaxially positioned therebetween; terminal means for feeding ultrasonic frequency electrical energy to said electrode; a cylindrical rear dummy section having a front face contacting one piezoelectric disk of the driving element, a rear face, the dummy section having a constant outside diameter from the front face to the rear face, and a concentric portion having a smooth cylindrical outer sealing surface of reduced diameter extending from said rear face; a front section having a cylindrical portion, the cylindrical portion having a rear face contacting the other piezoelectric disk of the driving element and a front face, and an amplifying portion extending from the front face of the cylindrical portion, the amplifying portion comprising a probe having a tip that forms an atomizing surface, an axial passage being provided through the length of the transducer assembly from the rear face of the rear dummy section to the atomizing surface, and a portion of the passage adjacent the driving element in both the front atomizing section and the rear dummy section being enlarged and internally threaded; a tubular central bolt having an externally threaded portion engaging said internally threaded portion of the passage in both the front atomizing section and the rear dummy section with sufficient torque to connect the front atomizing section and the rear dummy section under a tension that provides all of a predetermined total compressive preload on the driving element, the externally threaded portion extending from a front end portion of the bolt located in the front atomizing section and formed with a smooth cylindrical sealing surface to a rear feed tube portion of the bolt located in the rear dummy section and extending axially beyond the rear end of the dummy section; and means for sealing the piezoelectric disks from contact with the liquid being atomized, said means comprising a resilient first annular sealing member disposed between said sealing surface and the axial passage in the front section, to prevent liquid flowing in the passage from reaching the inner circumferential surfaces of the piezoelectric disks, and an enclosed circular cylindrical shell surrounding the transducer assembly, the cylindrical shell having a front end wall provided with a first cylindrical passage that loosely receives the cylindrical portion of the front section, a rear wall provided with a second cylindrical passage that loosely surrounds the concentric portion extending from the rear face of the dummy section, a resilient second annular sealing means disposed between the inner surface of the first cylindrical passage and the circumference of the cylindrical portion of the front section, and a resilient third annular sealing means disposed between the inner surface of the second cylindrical passage and the outer sealing surface of the concentric portion, the radial spacing between the cylindrical portion of the front section and the first cylindrical passage and the radial spacing between the concentric portion of the rear dummy section and the second cylindrical passage being respectively less than the radial thicknesses of the second and the third annular sealing means when unconstrained, so that the second and third annular sealing means are radially compressed between said passages and said cylindrical and concentric portions, respectively, and wherein said first and second annular sealing means are unconstrained in the axial direction, with no axial pressure exerted thereon.

Claim 8

An atomizing transducer assembly according to claim 5 wherein said enclosed shell comprises a cylindrical cup and a cylindrical cap threadedly fitting on said cup.