Issues regarding the start-up of expansion joints
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For tie-rope type expansion joints used in high-temperature pipelines, some bolts need to be loosened and others tightened at the time of commissioning; what determines which bolts should do what?
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At the start of work, I’ve never seen any tight ones; all I’ve seen were loose ones.
For tie-rod type expansion joints used in high-temperature pipelines, some bolts need to be loosened and others tightened at the time of commissioning. What determines this? In the case of constrained expansion joints, it is necessary to check whether the load-bearing components on the expansion joint are in a constrained state both before the system starts operating and during operation. For example, the spherical nuts and spherical (conical) washers on the tie rods must be in a tightened state, with no loosening or damage that may have occurred during transportation or installation. In the same product, any pull rods marked with a yellow label must have their nuts at both ends removed or loosened, so that the product can easily absorb displacements (along the axis of the pipe) during operation. For non-restrained expansion joints, the tie rods and nuts on the product should be removed; they serve as rigid supports during transportation or for adjusting the pre-deformation of the product, and must be taken out before the system is put into operation.