| 摘要 |
<p>A diaphragm 10 comprises a first circular portion 12 that is deformable between first and second configurations (see fig.2a and fig.2c); and a second annular portion 14 that is deformable between first and second configurations whilst the first circular portion12 is in the first configuration (see fig.2a and fig.2b). The second annular portion 14 surrounds the first circular portion 12 (see fig.1). A pneumatic pressure detector 20 comprising the diaphragm 10 has a housing 32, whereby the diaphragm 10 is secured to the housing 32 to define first and second plenums 28,30 within the housing. Increasing the pressure within the first plenum 28 causes the second annular portion 14 to deform between first and second configurations and then further increasing pressure causes the first circular portion 12 to deform between first and second configurations.</p> |
