Ключевые слова: background, bend, bolt, carbon, cast, connector, construction, control, drain, element, engineering, equipment, faucet, fitting, flex, flexible, fuel, gas, industrial, industry, iron, line, main, mechanical, metal, object, off, oil, old, petrol, petroleum, pipe, pipeline, plumbing, pressure, refinery, set, sewage, sewer, steel, supply, symbol, system, tap, technology, tube, turn, valve, water, wheel,