Ключевые слова: background, blue, bolt, business, connection, construction, control, energy, engineering, equipment, factory, fuel, gas, gasoline, icon, illustration, industrial, industry, insulation, iron, isolated, line, machine, metal, natural, oil, petroleum, pipe, pipeline, piping, plant, plumbing, power, pressure, production, pump, refinery, sewerage, steel, supply, system, tap, technology, tube, valve, water, white, yellow,