ESET-212 Lecture Notes - Lecture 15: Mercury Switch, Float Chamber, Boiler Feedwater
Document Summary
Low water fuel cut-off device: working principle of the controller. Low water cut-off controller is used to control the water level inside the drum. The main function is to protect the drum from overheated because of the low water level. There is a floating ball connected with a lever inside the floating chamber. When the water maintains the normal operating water level, the pump is off. The gauge glass is used to observe the water level. Draw the switch with the contacts shown and describe their function. There are two mercury switches inside the chamber. The mercury switches sense the signal of water level in the float chamber then send the signal made by the wire contact. The 2-wire switch (shown on the left) operate first. If the water level goes below the normal operating water level, the mercury switch turns on the pump.
