Ultrasonic Flow Meter
An ultrasonic flow meter is disclosed comprising at least one ultrasonic transducer, wherein the transducer comprises a piezoelectric disc, a nonconductive polymeric material and an electrically conductive layer between the piezoelectric disk and the nonconducting polymeric material.
1 . An ultrasonic flow meter comprising at least one ultrasonic transducer, wherein the transducer comprises a piezoelectric disc, a nonconductive polymeric material and an electrically conductive layer between the piezoelectric disk and the nonconducting polymeric material.
2 . The ultrasonic flow meter according to claim 1 , further comprising at least two ultrasonic transducers, wherein each of the transducers comprises a piezoelectric disc, a nonconductive polymeric material and an electrically conductive layer between the piezoelectric disk and the nonconducting polymeric material.
3 . The ultrasonic flow meter according to claim 2 , wherein the nonconducting polymeric material of the at least two transducers comprises one monolithic piece of material.
4 . The ultrasonic flow meter according to claim 2 , wherein the electrically conductive layers of the at least two transducers are electrically connected by a connecting electrically conductive layer deposited on the nonconducting polymeric material.
5 . The ultrasonic flow meter according to claim 1 , wherein the nonconducting polymeric material comprises a part of a housing for an electronic circuit.
6 . The ultrasonic flow meter according to claim 5 , wherein the housing comprises a hermetic enclosure containing the one or two transducers as well as the electronic circuit.
7 . The ultrasonic flow meter according to claim 1 , wherein the nonconducting polymeric material comprises a composite material reinforced by fibres.
8 . The ultrasonic flow meter according to claim 1 , wherein the electrically conductive layer is deposited on the nonconducting polymeric material using vapour deposition.
9 . The ultrasonic flow meter according to claim 1 , further comprising a coupling layer between the electrically conductive layer and at least one electrode on the piezoelectric disc.
10 . The ultrasonic flow meter according to claim 9 , wherein the coupling layer comprises an electrically conductive adhesive.
11 . The ultrasonic flow meter according to claim 10 , wherein the electrically conductive adhesive comprises a mixture of a nonconductive glue and electrically conductive metallic balls.
12 . The ultrasonic flow meter according to claim 9 , wherein the coupling layer comprises a dielectric material.
13 . The ultrasonic flow meter according to claim 1 , wherein the electrically conductive layer is electrically connected to an electronic circuit via an electrical conductor.
14 . The ultrasonic flow meter according to claim 13 , wherein at least a part of the electrical conductor is a flexible connection, such as a spring.
15 . The ultrasonic flow meter according to claim 1 , wherein the electrically conductive layer is at least partly reinforced by a protective layer.
16 . The ultrasonic flow meter according to claim 15 , wherein the protective layer is electrically conductive.
17 . The ultrasonic flow meter according to claim 7 , wherein said fibres comprise at least one material selected from the group consisting of glass fibres and mineral fibres.
18 . The ultrasonic flow meter according to claim 8 , wherein said vapour deposition comprises at least one deposition selected from the group consisting of chemical vapour deposition and physical vapour deposition.
19 . The ultrasonic flow meter according to claim 11 , wherein said conductive metallic balls comprise at least one material selected from the group consisting of silver, gold, and copper.