Lubricants are considered the "blood" in all equipment, machinery, automobiles, transport vehicles and systems of public plants. Lubricants are considered the "blood" in all equipment, machinery, automobiles, transport vehicles and systems of public plants. Lubricants are considered the "blood" in all equipment, machinery, automobiles, transport vehicles and systems of public plants. Lubricants are considered the "blood" in all equipment, machinery, automobiles, transport vehicles and systems of industrial plants.