1. Positive displacement pump: use the periodic change of the volume of the working chamber to transport liquid.

2. Vane pump: use the interaction between blades and liquid to transport liquid.

It is widely used in shipbuilding, oil exploration, truck, etc. In 2008, the ship output reached 15000 tons, and the deadweight tons accounted for 21% of the world market. By 2015, it will become the world's largest shipbuilding country. In order to ensure the normal navigation or mooring of the ship and meet the living needs of the crew and passengers, each ship should be equipped with a certain number of marine pumps that can play a corresponding role. Marine pumps are one of the important auxiliary engines. According to incomplete statistics, among various marine auxiliary machinery and equipment, the total number of marine pumps of various types and purposes accounts for 20% - 30% of the total amount of marine machinery and equipment, and the price of marine pumps also accounts for a large proportion of the cost of marine equipment. In the total cost, marine pumps account for 4% - 8% of the cost of marine equipment. Generally, the purchase of marine pumps for a medium-sized ship can reach more than 10 million yuan. When it comes to the key pump market, it is necessary to mention that China has completed the "West to East Gas Transmission" project, which also requires pump products. At the same time, the state will also build other natural gas transmission pipelines, in which a large number of pump products are required.