Influence of the type of the heat-insulating material used on the state of the bricking of ship boilers
It is shown that when the cardboard MKRKL-450 is deformed, the seal of the fixing bolt becomes leaky, and the air in the boiler air duct enters first behind the masonry, and then through the rod into the furnace space. In this case, the brick is cooled in the region of the hole and the bolt, which creates high temperature stresses. There is a cyclic mechanical load in the places where the bolt is attached to the brick due to the successive increase or decrease in length. When air leaks through the slot into the furnace, the edges of the brick are intensively cyclically cooled, which also contributes to the development of fatigue failures. At the same time, the destruction of the cardboard and the weakening of the bolts occur, which cease to hold the bricks, exposing them to the combined action of mechanical and thermal stresses. This leads to the occurrence of fatigue cracks, the destruction of the mortar and the bricks themselves. The unsatisfactory mechanical properties of MKRKL-450 cardboard, established during the study, lead to an initial breakthrough of air under the brickwork, abnormal compression of the cardboard with residual deformation, violation of the structure of the cardboard, its destruction and “blowing”, the subsequent weakening of the brick fit, the appearance of additional degrees of freedom of it fastening, overheating of bricks and mortar, its chipping, falling out of bricks, ingress of an air-gas mixture into neighboring areas and a chain reaction of masonry destruction.