MEANS FOR CALIBRATING PRESSURE SWITCHES AT EXTRA-LOW PRESSURE SETTINGS

摘要

ABSTRACTA simplified calibration mechanism is provided fora pressure switch using an adjustable, spring-biased plungerarrangement for controlling the trip force and hence thepressure to which the switch responds. The mechanism includesan especially configured lever pivoted at one end, contactingan especially shaped cam as a follower at its other end and theplunger at its mid portion. A first calibration device isprovided at the lever's pivoted end to adjust the normal low-high pressure settings of the switch. Another calibrationdevice is provided to isolate the lever and cam from theplunger for effecting a precise setting of the pressure switchat extra-low pressures.