AEROSOL GENERATORS
An aperture plate is formed from a palladium nickel alloy comprising about 89% palladium and about 11% nickel. There is a generally fine substantially equiaxed grain microstructure throughout the thickness of the aperture plate. The average grain width (W) is in the range of from 0.2 μm to 5.0 μm, in some cases from 0.2 μm to 2.0 μm. Because the grain structure is equiaxed (L/W=1) the grain length (L) is the same as the grain width. The improved aperture plate extends the life of nebulisers, eliminates the risk of premature and unpredictable failure of a nebuliser in service, eliminates the risk of product returns from hospitals and patients, and eliminates the possible risk of fragments of the aperture plate breaking free from the nebulizer.
1 . An aperture plate body having a plurality of apertures extending between a first surface and a second surface, the plate being formed from a palladium nickel alloy comprising about 89% of palladium and about 11% nickel and having a generally fine randomly oriented substantially equiaxed grain microstructure throughout the thickness of the aperture plate.
2 . An aperture plate as claimed in claim 1 wherein the average grain width is from 0.2 μm to 2.0
3 . An aperture plate as claimed in claim 1 wherein the average grain width is from 0.2 μm to 1.0
4 . An aperture plate as claimed in claim 1 wherein the average grain width is approximately 0.5 μm.
5 . An aperture plate as claimed in claim 1 wherein the average grain width is from 0.2 μm to 8.0
6 . An aperture plate as claimed in claim 1 wherein the average grain width is from 0.2 μm to 5.0 μm.
7 . An aperture plate as claimed in claim 1 wherein the average grain width is 1.0 μm to 4.0 μm.
8 . An aperture plate as claimed in claim 1 wherein the aperture plate has a thickness of from 59 to 63 microns.
9 . An aperture plate as claimed in claim 1 which is domed-shaped in geometry.
10 . An aerosol generator comprising an aperture plate as claimed in claim 1 and a vibrator for vibrating the aperture plate.
11 . An aerosol generator as claimed in claim 10 wherein the vibrator is configured to vibrate the plate at a frequency of from 125 to 155 kHz.