Pneumatic indicator for detecting liquid level

A pneumatic sensor/indicator device, comprising:

• a sensor housing having a bellows receiving chamber created in the sensor housing;
• an inlet pressure port and a reference port;
• an elastic bellows positioned in the bellows receiving chamber, the bellows having an inner chamber isolated from the bellows receiving chamber and in communication with the inlet pressure port, the bellows receiving chamber external to the bellows being in communication with the reference port;
• an indicator dome connected to the sensor housing;
• an indicator member positioned in the sensor housing in a non-indicating condition and axially displaced at least partially into the indicator dome by extension of the bellows defining an indicating condition having the indicator member visible through the indicator dome;
• a shaft slidably disposed in the sensor housing, the bellows further being frictionally connected to the shaft at a mounting ring of the bellows such that longitudinal motion of the bellows causes axial motion of the shaft, a pressure in the inlet pressure port exceeding a pressure in the reference port causing an extending motion of the bellows and thereby axial motion of the shaft;
• and
• a first magnet connected to the shaft and thereby co-axially displaced during axial motion of the shaft, and further being operably associated with the indicator member to cause movement of the indicator member when axial motion of the shaft occurs.