Flanges With the rapid development of domestic foreign minister pipeline construction, pipeline pressure test has become an essential important link, before and after the pressure test, must pass the ball sweep line for each section of the pipeline, the number of times is generally 4~5. Especially after the pressure test, it is difficult to clean the stored water in the pipeline, so there will be more cleaning times.

The construction method of repeated welding head is adopted at the ball receiving place, which has the following problems: first, it increases the labor intensity of workers; Second, the repeated welding head method has high consumables, large equipment and high cost. In order to solve the problems of high labor intensity, high consumable material, large equipment times and high cost, a new construction method of quick opening large flanged blind plate is proposed when using repeated welding head method at the service point to sweep through the ball after pressure test. The construction method introduces the structure, working steps and strength checking of the fast-opening blind plate. Through the application in gas pipeline engineering, it is proved that the construction method of quick opening blind plate improves the work efficiency by three times compared with the construction method of repeated welding head, which not only reduces the labor intensity of workers, but also reduces the cost. Flange before the measurement needs to do a certain preparation work, according to a certain way and method of measurement, according to the specific situation to determine different measurement methods, to ensure the accuracy of measurement.

The following introduces the measurement method of flange: Preparation before measurement:

1. Before measurement, according to the position of the flange, the connecting flanges of the equipment should be first sketched and numbered consecutively, so that the fixture can be installed in a certain way and principle to ensure normal use.

2. Because the flange may have different outside diameters, different openings (different cores), and the gasket thickness is not the same, so the processed fixture should not be interchangeable with the flange on the side, so measuring the size and number of each part is the key to the processing and installation of the fixture.

3. Arrange three people for measurement, including two for measurement and one for proofreading and filling in the form. Use vernier calipers for measurement tools, and use external calipers and steel ruler if there is no condition. Measurement is a meticulous work, is the premise of fixture installation, measurement and record must be prepared correctly, when filling in the form must be careful and clear. In the real

International measurement work to cooperate with each other, can be in accordance with the correct principles of cooperation and use.