ACCELERATION RESPONSIVE DEVICES

摘要

1,240,692. Detecting vibrations; sensing acceleration. HONEYWELL Inc. Sept. 27, 1968 [Oct.18, 1967], No.46121/68. Headings G1J and G1K. Apparatus, for providing a fluidic output signal when excessive vibrations occur in a system, comprises a mass 12 held in one position during accelerations below a predetermined value but movable, when that value is exceeded, to another position, where it is held, a fluidic relay 13 producing a signal when this position is assumed. The mass 12 is mounted to oscillate about a vertical axis 16 by a flexible hinge 16 and has arms of magnetic material whose ends 12A, 12B are influenced by magnets 50, 51 attached to stops 30, 32 and also by a spring 20, tending to turn the mass 12 clockwise, which may be adjusted and locked by screws 19, 21 to predetermine the critical value of acceleration. The apparatus is set initially with the end 12A in contact with an adjustment screw 31 in magnet 50. When vibrations occur producing a force large enough to dislodge end 12A from magnet 50, the end 12A moves away from magnet 50 as end 12B moves towards magnet 51 causing a respective decrease and increase in the forces of attraction so that the end 12B snaps against magnet 51. This causes a member 35 to move towards the relay 13 (see Group G3) and to tilt a trip bar 36. This unseats a ball valve allowing fluid to flow from a passage 40 into the relay 13 so that the pressure in a passage 43 decreases sharply, providing a signal which may be used to actuate a fluidic amplifier. Mechanism shutting down the whole system (e.g. a natural gas line pumping system) may be operated by the amplifier fluidic signal. To avoid shut down due to temporary excessive vibration e.g. when starting, the apparatus may be automatically reset a pre-set interval after each signal. To this end unseating the ball valve also allows fluid to vent from a pressurized chamber 106 in the reset mechanism, Fig. 4, through a restriction 44A in a passage 44 and the relay exhaust 41. As the pressure in chamber 106 decreases a spring 103 pushes a diaphragm 100 down retracting its central pin 101, allowing a leaf-spring 84 to push a resetting bar 45 which pushes both the end 12A against magnet 50 and trip bar 36 to initial position. When automatic resetting is not wanted, a resetting selector arm 82 is turned to a manual position in which an inclined ridge 90 prevents the spring 84 from moving down when the pressure in chamber 106 diminishes. However the end of spring 84 can bend when a manual reset button 105 is pushed.