What kind of certification does environmentally friendly oil-free air compressors need to pass to prove their oil-free performance?

A. Food, drugs, electronics, chemicals B. Home use, commercial use C. Oil and gas, construction, logistics D. Manufacturing, oil and gas, construction Answer: A. Food, drugs, electronics, chemicals

A. Screw B. Piston C. Centrifugal wheel D. Scroll disk answer: B. piston

A. 0.5-0.6 B. 0.7-0.85 C. 0.9-1.0 D. 1.1-1.2 Answer: B Analysis: When selecting the model, it needs to be multiplied by an efficiency factor of 0.7-0.85.

A. Price and brand B. Performance, price and brand C. Appearance and color D. Production date and transportation method Answer: B. Performance, price and brand

A. Higher B. Lower C. Same as oil injection air compressor D. The answer cannot be determined: B Analysis: Oil-free air compressors usually consume less energy and improve energy efficiency due to reduced use of lubricating oil.