Float level control circuit

The float-type liquid level control circuit is very simple, but it is large in size and has low sensitivity. If the mechanical connecting rod is corroded, it is easy to get stuck and cause
failure. Often used in situations where reliability is not required.
The circuit is shown in Figure 11-1. It belongs to the filling type liquid
level automatic control circuit. That is, when the liquid level is lower than the lowest limit line
, the pump starts working and pumps the liquid into the liquid storage container
. If it is a withdrawable liquid level automatic control, you only need to reverse the positions of the limit switches SQi and SQ2
in the figure. At this time, when the liquid level is higher than the maximum limit line, the pump starts working and pumps the liquid out of the liquid storage container. The above two liquid level control methods both maintain the liquid within a certain limit.     In the figure, SBi is the start button and SB2 is the stop button, which is used when automatic control fails. When the automatic control fails (the limit switch fails) the buzzer HA will send out an alarm signal.