Technological diagram of the installation crane unit with a diameter of 1020 mm.

The technological scheme for the installation of a crane unit with a diameter of 1020 mm includes the following stages:

1. Preparation. Workers are provided with the necessary equipment, tools, inventory, first aid supplies, drinking water, and fire safety equipment. Lifting devices are checked and tested. Structural elements, pipe blanks, and reinforced concrete products for the installation of the crane unit are delivered to the construction site. 1
2. Trench laying of the pipeline and backfilling. At the installation sites of the crane unit, the trench with the pipeline must remain unfilled on one side of the ball valve at a distance of 25 m and on the side of the overlap at a distance of up to 80–90 m. 1
3. Checking the axis of the pit. The correctness of transferring the actual axis of the pit and its compliance with the project position is checked using geodetic control tools. 1
4. Marking on the pipeline. According to the actual axis of installation, marking is made on the pipeline for cutting the pipe for the crane unit, taking into account the overlap on one side of the valve. 1
5. Cleaning the surface of the pipeline. In the cutting areas, the surface of the pipeline is cleaned of insulation for a width of at least 150 mm on both sides from the cutting point. 1
6. Removing the cut section of the pipeline and closing the ends of the pipeline with inventory plugs.  1
7. Excavation of pits for welding. Pit dimensions: length — 0.5 m on both sides from the joint, width — 0.6 m on both sides from the side edges of the pipe, depth — 0.7 m from the bottom edge of the pipe. 1
8. Installation of portable inventory ladders for the descent and ascent of workers.  1
9. Installation of a transition bridge over the trench.  1
10. Edge cleaning. The edges and adjacent inner and outer surfaces of the pipe are cleaned to bare metal over a width of at least 25 mm from the end of the pipe. 1

Also, during the installation process, preparation for the assembly and welding of the valve unit is carried out: the valve body and electric drive are freed from packaging, their integrity and completeness are checked, grease is removed from the surface, factory edge preparation on transition pipes for welding and wall thickness are checked.