| 摘要 |
<p>A variable orifice liquid flow meter comprising a body (3), a bore (11) in the body defining a flow tube for liquid, a sharp edged orifice (9) in the bore, a piston (7) having a head (27) capable of blocking the orifice and a stem (29) by which the piston is supported for axial movement relative to the orifice, and resilient means (5) urging the piston head into a position to block the orifice, characterised by support means (2) in which the stem (29) of the piston (7) is axially slidably housed and shielded from liquid flow through the bore (11). Preferably the support means (2) has a blind bore (36) in which the piston (7) is slidably mounted.</p> |
