GB955405A - Sonic atomizer for liquids - Google Patents

Abstract

955,405. Spray producers. ESSO RESEARCH & ENGINEERING CO. Oct. 1, 1962, No. 37164/62. Heading B2F. Liquids are vaporized by a method wherein a gas is subjected to sonic or ultrasonic energy vibrations and thereby given a pulsating movement and the liquid is flowed into an area of said pulsating gas movement and thereby vaporized. High frequency alternating voltage from a source 10 is applied to a piezo-electric element 18 which is bonded to the larger end of a conical resonator element 22. The element 18 is of barium titanate or other suitable ceramic material. The element 22 is of aluminium, or it may be of brass on stainless steel, and it is maintained in spaced relation to a ring 34 by screws 38, directed radially inwards and having pointed ends which bear on the element 22 along a circumference which coincides with the node of the vibrations therein. Screwed into the smaller end of the resonator element 22 is a bolt 24 and just clear of the bolt-head is a plate 42 in which is an orifice 44 in axial alignment with the element 22 and bolt 24. The bolt is exchangeable with others of different head diameters. The plate 42 is clamped to a ring 48 which may be adjusted upwards and downwards, being carried by a yoke 54 adjustable on a post 56. The post 56 rises from a block 62 which is slidable on the base 26, as controlled by a screw-threaded rod 72 and spring 82, to give backwards and forwards adjustment to the plate 42. The orifice 44 is surounded by a lip extending away from the resonator. The liquid to be atomized is directed to the face of the plate 42 through a feed tube 84, which is adjustable in position, and runs down on to the lip around the orifice. The high frequency vibration of the element 22 causes the bolt 24 to act as a pump and send a rapidly pulsating air stream through the orifice, and as liquid passing over the edge of the lip is struck by the pulsating air jet it is thereby atomized. As the bag 86 of atomized liquid is driven away from the orifice it will tend to draw into it air, in the direction shown by the curved arrows, Fig. 1, which, if the liquid is fuel oil, assists in forming a combustible mixture. To increase the heating-up effect on the liquid there may be a group of lipped orifices instead of a single one and to increase the air pumping effect there may be a collar on the plate, on the reverse side from the lip or lips, surrounding the head of the bolt 24. In a modification the orifice plate may be horizontal so that the liquid forms a pool, from which some flows over the orifice lip. Experiments are described dealing with the effect of orifice diameter, distance between the bolt head 24 (transducer tip) and the orifice, air jet velocity and other factors with respect to different liquids atomized.