161. The winch drive engine on the harbor tug to which you are assigned is fitted with a Roots-type blower as shown in the illustration. What statement is true concerning this blower

The correct answer is that rotor 1 turns counterclockwise, rotor 2 turns clockwise, area 3 is the discharge passage, and area 4 is the suction passage. This configuration ensures air is drawn in through area 4 and moved to area 3 as the rotors rotate in opposite directions.