Preparation before measuring carbon steel weld neck flanges

　　With the rapid development of foreign pipeline construction in China,carbon steel weld neck flanges becomes an essential part of pipeline pressure test. Before and after pressure test, it is necessary to conduct ball sweeping for each section of pipeline, generally 4-5 times. Especially after the pressure test, it is difficult to clean the water in the pipeline, and the cleaning times will be more. There are some problems in using the construction method of repeated welding head at the ball receiving place: first, increasing the labor intensity of workers; second, the method of repeated welding head has high consumables, needs more large equipment and costs.

　　In view of the problems such as high labor intensity, high consumables, many times of large-scale equipment and high cost in the process of ball cleaning after pressure test of long-distance pipeline, a new simple and quick opening large-scale ASTM A105 Carbon Steel FF Dn150 Class150 Weld Neck Flanges construction method is proposed. The construction method introduces the structure, working steps and strength check of the quick opening blind plate.

　　It is proved that the construction method of quick opening blind plate is three times more efficient than the construction method of repeated welding head, which not only reduces the labor intensity of workers, but also reduces the cost. Before the measurement of carbon steel weld neck flanges, certain preparations shall be done. The measurement shall be carried out in a certain way and method. Different measurement methods shall be determined according to the specific situation to ensure the accuracy of measurement.

　　The following describes the measurement method of carbon steel weld neck flanges: preparation before measurement:

　　1. Before measurement, according to the position of carbon steel weld neck flanges, first draw the sketch of each connecting carbon steel weld neck flanges of the equipment, and number them consecutively, so that the fixture can be installed according to the number, in a certain way and principle, to ensure normal use.

　　2. Because the carbon steel weld neck flanges may have different outer diameter, staggered joint (not concentric) and unequal gasket thickness during installation, the processed clamp shall be corresponding to the carbon steel weld neck flanges on its side and shall not be interchanged. Therefore, measuring the size and number of each part is the key to machining and installation of the clamp

　　3. When measuring, it is better to arrange three people, two of whom are measuring, one is checking and filling in the form, and the measuring tool is vernier caliper. If there is no condition, external caliper and steel ruler can be used. Measuring is a detailed work, the premise of fixture installation, and the measurement and record must be prepared correctly, When filling in the form, we must be careful and clear. In the actual measurement work, we should cooperate with each other and be able to cooperate and use according to the correct principle.