HO Scale Heat Exchanger+Pig Launcher

A pig launcher is an installation that is used for cleaning and inspecting pipelines. A thing called a pig scrapes the walls of the pipe clean, they can also scan the pipe walls for defects etc. The pipe is full of oil or gas so this installation is used to get the pig into the pipe without the oil or gas escaping, because that would get rather messy.
Heat exchangers are used to heat up or cool down a liquid or a gas in industrial facilities like refineries, chemical plants, but also in food manufacturing and other plants.