Dust level indicator for vacuum cleaner filter bag - is operated by piston with by=pass allowing position recovery following transient differential pressure rise

摘要

A piston (4) arranged to be displaceable in a piston chamber (3) is connected to a restoring spring (11) and directly or indirectly coupled to an indicator element. The piston is exposed to atmospheric pressure on one side and to the reduced pressure in the dust chamber on the other. A by-pass (17) arranged between the high and low pressure is first opened when the piston reaches the end of its travel. The piston has an air channel leading to the end exposed to atmospheric press. which coincides with a channel (17) formed in the wall (16) of the piston housing in the end region of the piston stroke. USE/ADVANTAGE - Indicating fill level in fi lter bag in dust chamber of vacuum cleaner. Developed so that piston returns to position corresp. to differential pressure following transient rise in differential pressure.