The bent sections produced in our Pipeline Prefabrication Center can be divided into:

• bend knee pipes
• segmented knee pipes,
• flat offset pipes,
• spatial offset pipes.

For bent knee pipes, the maximum shoulder length is 6m, the longer arm should not be shorter than 0.5m. The maximum bending angle is 5 ° to 180 °. We have the possibility of bending 1.5D, 2D, 2.5D - depending on the diameter and wall thickness. Bending radii for a given diameter and wall thickness are given in the table. For the offsets, the maximum bending angle is from 5 ° to 90 °, and the length of the shorter projection of the arm does not exceed 1.1m. The ovalisation of the pipe at the bending site is from 1% to 4%. The shaping of the wall on the outside bending radius is:

• for R = 1,5D - max 25% of the wall thickness,
• for R = 2D - max 21% of the wall thickness,
• for R = 2.5 - max 18% of the wall thickness.

The accuracy of the bending angle is 0.5°.

Bending takes place on 10003CNC and 1008CNC bending machines. Another alternative for bending is the use of a Hamburg knee or segmented knee. We use Hamburg knees from DN80 to DN450 with wall thicknesses according to customer needs. The standard bend radius of the Burgers is 1,5D. The pipe bend is assembled using welding on the contact. Segmented knees are made according to the ZN-5003 standard, in the diameter range from DN125 to DN500 with a wall thickness up to 20mm. We use two basic cutting angles: 15 ° and 11.5 °. We obtain a maximum angle of 180 ° by using the right number of segments.