On the last day of March 2023, as the entire city is about to enter a weekend break, Dongfang Electric Corporation is back in the workshop, still busy.

"The cleaning and warehousing work must be completed within the next week, so everyone should seize the last few days and be ready for shipment at any time!" The atmosphere in the workshop was somewhat tense, and Xu Kaijian, the person in charge of the assembly area of Dongfang Electric Turbine Branch, was arranging the deployment work.

Twenty days ago, the second butterfly valve in the factory passed the acceptance inspection and is now undergoing the final cleaning and warehousing work. In early April, this "butterfly" will cross the Pacific and Indian Oceans and "fly" to the Julino Hydropower Station, the largest hydropower station under construction in Tanzania with a total installed capacity, to take up his post. "The owner has been pressing hard, and the finishing work is too slow to wait," Xu Kaijian said.

On the morning of the same day, Wang Qingfu, the deputy director designer of the butterfly valve for the Julino project of the Dongfang Electric Machinery Research and Development Center, arrived at the scene early.

"We need to continuously pressurize the butterfly valve filled with water to a fixed value to conduct a sealing test to determine whether there are defects in various parts of the butterfly valve after assembly." Pointing to the pressure gauge on the valve body, Wang Qingfu introduced that according to national standards, the design pressure of the butterfly valve is 2.1 MPa, while the standard requirements proposed by Dongfang Electric Corporation itself have reached 3.15 MPa.

Butterfly valves, compared to water guiding mechanisms, are truly "faucets". Butterfly valve switches not only determine whether water can flow, but also control the size of the water flow. The shaft end connecting mechanical arms on both sides of the valve body unfold to resemble butterfly wings, hence the name "butterfly valve". The butterfly valve of the Julino project is the largest butterfly valve in the industry and the largest butterfly valve independently developed by Dongfang Electric Co., Ltd. to date. Its total weight exceeds 450 tons and its diameter reaches 6.3 meters.

This also means that conducting a sealing test on such a large object is highly demanding and difficult.

"This is a slow pressurization process, which takes more than 2 hours to reach 3.15 MPa. We started the water storage work a few days in advance." Wang Qingfu introduced that according to the test process, a cycle would take about 1 day, and to complete the acceptance, it would take three consecutive sealing tests to complete.

During the few days of acceptance, Cui Xingguo was also mentally tense. In his hands, a challenging experiment was also conducted on this butterfly valve.

"We are conducting cleaning assembly and manufacturing tests, which simply means that each test cycle is completed, and the valve body does not need to be cleaned or replaced with water. The next step of testing is directly conducted to achieve blind observation." Cui Xingguo said that the purpose of doing so is to improve assembly efficiency, and also to "eliminate defects" and "optimize" the assembly process.

The second time I saw Cui Xingguo, it was at the Starlight Festival of the Third Tianfu Character Promotion Event in 2022. Upon meeting, the reporter asked him about the test results.

"It's been a success. We just need to shake off blind spots in every experiment, find new blind spots, and constantly improve and improve," Cui Xingguo said.

It is this relentless spirit of excellence that has allowed this huge steel "butterfly" to cross the oceans and showcase the charm of "Made in China" on the African continent. Editor/Sang Xiaomei