A Design And Implementation Of LNG Submerged Pump Testing System

As a specially designed pump, liquefied natural gas pump(LNG Pump) is used for remote mass transportation of LNG. As the media through this pump is liquefied natural gas with a low temperature, it can also be called cryogenic pump. With the wide use of the green energy LNG, the demand for LNG submerged pumps is on the rise. A large number of the current LNG submerged pumps in use are from imports. It’s of great importance to design our own products. In the process of pump design, we need a stably and highly automated test system to help the designer to test the pump performance effectively and accurately.In this paper, we designed a set of LNG pump test system consisting of hardware and software, according to the requirements of a company in Chongqing and performed the field operation of this test system with our partner company. Main works are as follows:(1) We analyzed the key parameters and structure characteristics of the LNG submerged pump from both theory and engineering experience, and the composition and function of the test platform on the basis of overall structure of the existing closed LNG submerged pump. After finishing the overall structure design of this test system, we put forward hardware and software schemes for the test system.(2) According to the scheme of hardware design, we finished the circuit design where PLC and inverter are the key components, then finished the power supply cabinet and control cabinet design and integrated all these components. On the basis of the random error and systematic error analysis of this test system, we considered the specific test system design according to provisions of the national standards GB/T 3216-2005 1 level precision.(3) According to the scheme of software design, we finished the lower computer software and upper computer software design respectively. The main function of the lower computer software includes data acquisition, filtering, data communication and output control, etc. In the filtering module, we analyzed the signal characters and adopted an analog input filtering based on STEP7-Micro/Win system database to eliminate signal noise effectively. The main functions of upper computer software include data communication and management, operation interface, accident alarming, report form, curving plotting and database operation. Upper machine and lower machine software system help control this test system operation automatically.Finally, we summarized the whole works and put forward some suggestions for further researches.