A. higher
B. lower
C. Same as injection air compressor
D. unable to determine
Answer: B
Analysis: Oil-free air compressors do not require replacement of lubricants and oil filters, so maintenance costs are low.
Answer: Follow the manufacturer’s instructions for draining and refilling the water tank.
Answer: It can monitor parameters such as discharge pressure, temperature, motor current, and lubrication water level.
Answer: It is designed to be energy-efficient and environmentally friendly, with low energy consumption and zero emissions.
Answer: It can be determined by observing the pressure differential indicator of the water filter or based on usage time and water quality.
Answer: It consumes less energy and operates more efficiently, resulting in lower operating costs.