Individual small gaps in the air ducts can be removed by welding. Otherwise, damaged pipes are renewed or repaired using pieces of pipe, preferably by welding or grade-matching, unthreaded pipes (threadless connections).
For renewal or repair of air brake air pipes, steel pipes with quality specification according to DIN 2448 (seamless steel pipes), DIN 2458 (welded steel pipes) or DIN 2391/ precision steel pipes/ are used. In DIN 25 570, Part 1, these pipes are presented in one overview.
Only chip removal tools are used to extend the pipes. Burrs are removed by smoothing the ends of the pipe.
Bending of pipes
The pipes are bent to a precise fit to the connection points so that they can be inserted without any tension.
It is unacceptable for the pipes to bend under the heat of the vehicle itself. – Pipes must be bent cold with as large a bending radius as possible (see DIN 5508), in which neither creases nor cracks should occur. The use of sand or any other filler is inadmissible.
After bending, the pipes are cleaned by tapping, hitting and blowing from the inside with compressed air. Finally, the inner walls are lubricated with anti-corrosion oil.
After bending and before installation, the new pipelines, passage and pipe joints are checked for free passage with the help of a steel ball.
Pipe
As a rule, welding connections are performed as an overlapping seam. As a departure from the present, welds on straight pipe sections are placed approximately 100 mm from the end of the pipe as butt welds.
In doing so, the roughness appearing inside is removed without residue. Welding is not allowed on curved parts.
Repaired pipes must be strongly purged if this does not cause contamination of the pneumatic parts.
The main air duct is checked for free passage in the installed state with the help of a ball, if it has been replaced or individual pieces of pipes have been repaired.
Undismantled brake clutches and air shut-off valves are also checked. In doing so, the wires are checked with a steel ball from each connection at the end of the vehicle.
The main air duct is checked for free passage in the installed state with the help of a ball, if it has been replaced or individual pieces of pipes have been repaired.
Undismantled brake clutches and air shut-off valves are also checked. In doing so, the wires are checked with a steel ball from each connection at the end of the vehicle.
For pipe outside 42.4 mm /1 1/4 / with 20 mm ball For pipe outside 33.7 mm /1 / with ball 18 mm The size of the ball is not determined based on the nominal values of the pipe, but based on the most – the small passable cross-section.