Pumps are machines that convey fluids or pressurize them, and are mainly used to convey water, oil, slurries, acid and alkali liquids, emulsions, suspensions, gas mixtures and liquid metals, etc. They are common conveying equipments in mining, chemical and metallurgical industries, and different pumps differ in their structural appearances, load-bearing capacity, service life and application areas.There are many types of pumps, but we will only discuss two of them here: screw pump and gear pump. Understanding the difference between them is important for the correct choice of the desired product, which can effectively improve the service life and performance of mechanical equipment.