| 摘要 |
<p>Disclosed is a fluid level sensor including a float (12) mounted for movement in a mounting tube (10) by a pair of spiral springs (22, 24) which are relatively rigid in a radial direction but relatively flexible in a longitudinal direction. At the top of the float (12) a magnet (14) is located and at the top of the mounting tube (10), a Hall effect device (20) is located. As fluid enters the mounting tube through apertures (40) in the lower portion, the float (12) is gradually buoyed and moves closer to the Hall effect device (20) changing its electrical output. Because the springs (22, 24) position the float (12) inside the mounting tube (10), stiction and hysteresis in conventional float supports is eliminated as well as wear between the float and the outer tube. Measurement range may be changed by changing float length and outer tube length as well as the spring constants themselves.</p> |
