| CPC F28G 1/04 (2013.01) [B08B 9/043 (2013.01); B08B 9/0433 (2013.01); B65G 43/04 (2013.01); F28G 3/163 (2013.01); F28G 15/003 (2013.01); F28G 15/04 (2013.01)] | 20 Claims |

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1. An automatic blockage sensor circuit for controlling a drive motor configured to advance and retract at least one flexible lance, the apparatus comprising:
a first pressure transducer communicatively coupled with a forward air port of the drive motor, the first pressure transducer configured to generate a first signal based on a pressure at the forward air port;
a second pressure transducer communicatively coupled with a reverse air port of the drive motor, the second pressure transducer configured to generate a second signal based on a pressure at the reverse air port;
a microcontroller connected to the first pressure transducer and the second transducer, wherein the microcontroller is configured to:
determine a pressure differential while the drive motor is conveying the at least one flexible lance in a first direction, the pressure differential based on the first signal and the second signal,
compare the pressure differential to a threshold pressure, and
selectively energize a solenoid valve based on a result of the comparison, wherein the solenoid valve is configured to reverse pneumatic pressure connections to the drive motor when energized.
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