The horizontal pump is horizontally arranged (the liquid inlet pipe is lower than the liquid discharge pipe), and heating gas (set behind the pump or in front of the filter in front of the pump to prevent impurities from entering), seal gas, liquid discharge exhaust valve (discharge at low place and exhaust at high place) and return pipeline (return liquid inlet phase) are required.

Generally, there are three types of expanders, namely, low-pressure expander, medium pressure expander and liquid expander. For a certain type of gas expander, the greater the volume flow of working medium, the higher the efficiency. Generally, the efficiency of the low-pressure expander with a flow of more than 8000nm is 85 ∽ 88%, and the efficiency of the expander with a flow of less than 3000 ∽ 8000nm will be as low as 70 ∽ 80%.