Vertical reciprocating compressors are oil-free, highly reliable, and extremely versatile & are used to transfer LPG between tanks, off-load and load-out LPG, recover residual vapor and evacuate vapors for maintenance purposes. Typically they are used to unload barges, rail cars, transports and LPG delivery trucks. In many countries a compressor is used to off-load LPG at the auto gas stations. Reciprocating compressors work in a very similar manner as does as internal combustion engine but basically in a reverse process. They have cylinders, pistons, crankshafts, valves and housing blocks. Heavy duty reciprocating compressors designed to maximize the reliability and availability of the complete equipment package. Non-lubricated cylinders are kept to avoid the presence of oil in the gas (oil content pollutes the storage banks and accumulates with each refilling, reducing the available volume in the vehicle tanks), and minimize lubricating oil expenses.