| 摘要 |
<p>1,274,276. Fluid regulation; fluid-pressure servomotor systems. ATLAS COPCO A.B. Aug. 13, 1969 [Aug. 26, 1968], No.40499/69. Headings G3H and G3P. [Also in Divisions G1] The body of a fluidic device 1 has formed therein a substantially venturi-shaped main passage having inlet and outlet portions 3 and 4 respectively, and a signal passage 6, the passages being rectangular in cross-section and so disposed that the angle 7 between the signal passage 6 and the centre line of the main passage lies between 20 degrees and 60 degrees, and is preferably equal to 45 degrees. The signal passage is arranged to intersect the main passage at the minimum cross-sectional area portion 5 of the main passage and at this branch-off point the main passage cross-sectional area increases discontinuously in a direction from the inlet 3 to the outlet 4. With the above arrangement and in the absence of an impedance downstream of the outlet portion 4, flow within the inlet portion 3 adheres, inter alia, to wall 9 thereof, detaches itself from the wall at the point of intersection of the main and signal passages, and re-attaches itself to a wall 8 of the outlet portion at a point downstream of the intersection. Thus no flow enters the signal passage 6. Upon introducing an impedance downstream of portion 4, flow from the inlet portion 3 can be distributed between the portion 4 and passage 6, or diverted entirely into passage 6, Figs. 2a, 2b, 2c (not shown). Alternatively, Figs.3 and 4 (not shown), more than one signal passage may be provided. When applied to controlling a valve, Fig. 6, the device is connected to a signal source 33, an adjustable restrictor 34 and a signal responsive control 31 which may comprise a deflectable membrane to which a valve spindle is secured, the position of this spindle being determined by the state of restrictor 34 and hence by the pressure in signal passage 6.</p> |
