Key points of explosive expansion of heat exchanger unit

Key points of explosive expansion:

1. The dosage shall be selected correctly. If the dosage is small, the pipe is not easy to expand firmly, and if it is too large, the pipe will burst, resulting in large plastic deformation of tubesheet and pipe hole, and it will enhance the difficulty of repair.

2. The clearance between pipe and pipe hole shall be reasonably controlled. If the gap is too small, it is easy to cause only elastic deformation between the pipe and the tubesheet, and the pipe cannot be expanded tightly. If the gap is too large, it is easy to cause excessive deformation of the pipe and crack, resulting in leakage or not tight expansion of the pipe, that is, "loose expansion".

3. The tubesheet hole of the heat exchanger unit must be slotted. Because the explosive expansion has a much better filling degree to the groove than the mechanical rolling expansion, it is easy to produce stronger tensile force.

4. The pressure resistance of explosive expansion joint increases with the decrease of the surface roughness of the joint. In order to enhance the fluidity of plastic deformation during explosive expansion joint, the surface roughness of pipe and expansion joint should be reduced as much as possible.

5. The same batch of detonators shall be used for the same explosion, and the lead materials shall also be the same, so as to prevent the cartridge from being brought out and damaging the pipe due to different initiation time.

6. A certain distance must be kept for the simultaneous initiation of multiple holes. Generally, the hole spacing is about 1.5 times of the pipe diameter, and the two ends of the pipe orifice cannot be detonated at the same time. Safety protection measures shall be taken at the initiation site, working procedures shall be formulated, safety monitoring shall be provided, and special personnel shall be responsible for command.