GB886751A - Valve for flow control of liquids - Google Patents

Abstract

886,751. Valves. TECHNICAL CERAMICS Ltd. (Gulton Manufacturing Corporation). Feb. 27, 1958, No. 6357/58. Class 135. A valve for flow control of liquids comprises a housing 10 having at least one inlet 11 and at least one outlet 12 or 13, a fluid flow path connecting the inlet and outlet, a piezo-electric sensitive element in the form of a plain or annular disc 17, the element acting as a valve closure means and being bonded to a piezoelectrically inert backing 16 of similar shape, the element and backing being supported centrally against movement in the axial direction by supporting means 14a mounted in said housing to allow vibration of the sensitive element in a flexural mode, the element being so positioned within the flow path that when the element is in its rest position it contacts a seating 20 in the housing so that there shall be no flow of liquid from the inlet 11 to the outlet 12, and wherein upon exciting said piezoelectric element such that the contact between said element and said housing seating is varied in accordance with said excitation, flow is allowed between the inlet and outlet. As shown, flow to the two outlets 12, 13 is controlled by similar elements 17, 19. The seatings 20, 21 must be insulated either from housing 10 or from face electrodes (not shown) of the elements 17, 19. With the elements 17, 19 oppositely polarized and their face electrodes electrically connected together and a suitable alternating voltage applied between the housing 10 and the face electrodes, the elements 17, 19 together with their backing discs 16, 18 will vibrate in a flexural mode in phase with the excitation so as to vary the contact between the elements 17, 19 and the end seatings 20, 21 and permit phases of flow to the outlets 12, 13 alternating with phases of interrupted flow, the flows periods from the respective outlets being in opposite phase. Under the same conditions of electrical connections and with the elements 17, 19 polarized in the same direction, the flow periods to the outlets will be simultaneous. If the elements 17, 19 are polarized in the same direction and oppositely phased flows from the outlets 12, 13 are required, housing 10 must be an insulator, the face electrode of element 17 must be connected to backing disc 18, the face electrode of element 19 must be electrically connected to backing disc 16, and the exciting voltage applied between the respective backing discs 16 and 18. In an alternative embodiment the two elements in a dual valve are plain discs on backings integral with supporting stems which are inwardly directed from end supports towards concave seatings at the centre of the body. A single valve having one inlet and one outlet is also disclosed. The piezo-electric elements 17, 19 may be ceramic elements of barium titanate either alone or combined with additive materials such as strontium or lead titanate. Specification 834,236 is referred to.