<p>A piezo-electric valve has a housing (1) around a flow chamber (2) with an inlet (5; 6) and a seal to a jet (3; 4). The chamber incorporates a piezoelectric bending element (7) with a moving section (9) tip that deforms to open or close the valve. The tip has a flexible pad (13; 14). The valve seat face rests against a jet insert (15) that slides at right angles to the seat (17) and is located within a fixed socket (24). A heat expansion compensation member (25) is located between the socket and jet insert.</p>
