Vibratory atomizer

#This invention relates to vibratory atomizers for atomizing a liquid, for example ultrasonic atomizers for atomizing liquid fuel.

#It is difficult in practice to determine accurately the vibration node of a vibratory atomizer. The vibratory node is required to be determined so that the atomizer may be rigidly secured in the region of the vibration node to an associated mounting. Because there is virtually no vibration at the vibration node, little or no energy is thus lost from the atomizer into the mounting during periods when the atomizer is being vibrated.

#Hitherto, it has been customary only to take into account vibrations in the longitudinal direction of the atomizer. Radial vibrations and radial movement due to Poissons ratio effect have hitherto been neglected. This has mainly been because it is virtually impossible to find a plane of zero vibrations in both the longitudinal and transverse planes. Since the radial vibrations and radial movements are neglected, energy loss from the atomizer to its mounting occurs.

#Embodiments of the invention will now be described by way of example and with reference to the accompanying drawings in which:

#FIG. 1 shows a first vibratory atomizer in accordance with the invention positioned on an engine manifold;

#FIG. 2 is an end view of the atomizer as shown in FIG. 1 locking from left to right and without the engine manifold;

#Referring to FIGS. 1 and 2, there is shown a vibratory atomizer 2 comprising a nozzle portion 4 from which a liquid is ejected, and a body portion 6 having attached thereto vibration means in the form of a piezoelectric crystal 8. The atomizer 2 also comprises a cover 10 which fits over the body portion 6 and which is provided with a flange 12 having apertures for receiving screws 14. As shown in FIG. 2 the screws 14 pass through the apertures 15 in the flange 12, via spring washers 16, and enable the flange 12 to be tightly screwed down on to the surface 18 of an engine manifold 20.

#The cover 10 is provided with a centrally disposed aperture 22 through which passes an electrical lead 24. The lead 24 terminates in a block electrode 26 which engages with a copper spring contact 28. The contact 28 is brazed or otherwise connected at points 30 to the surface of the piezoelectric crystal 8.

#The body portion 6 is provided with an outwardly extending circumferential flange 32 which may be made of thin metal. A rubber O-ring 34 is slotted and fits over the flange 32. The O-ring 34 thus provides the sole means by which the body portion 6 and the piezoelectric crystal 8 are mounted within the cover 10. As shown in FIG. 1, the O-ring 34 fits in a recessed portion 36 formed by a shoulder 38 provided in the flange 12. The O-ring 34 is thus pressed against the surface 18 of the manifold 20 when the screws 14 are tightened and provides a seal at this point so that gases in the manifold space 42 do not escape.