Question 19General Subjects - Assistant Engineer

The correct answer is D) reduce the temperature of compressed air. After air is compressed by an air compressor, the temperature of the air increases due to the compression process. Coolers are used after the compression stage to reduce the temperature of the compressed air. This is important because compressed air at a lower temperature is denser, which improves the efficiency and performance of the compressed air system. The other answer choices are incorrect because they do not accurately describe the primary purpose of using coolers with air compressors. Dampening pressure pulses, ensuring complete expansion, and decreasing the density of compressed air are not the main reasons for using coolers.