Abstract: An insulation structure attached to a wall having a multitude of anchors projecting from the wall to support the insulation structure includes a permanent refractory layer adjacent the wall and a restorable refractory layer adjacent the permanent refractory layer. An anchor supports the refractory material and includes a first stud and a second stud. The second stud includes a cap connected to a shaft, wherein the cap defines an indentation on a side of the cap opposite the shaft. The second stud receives the first stud within the indentation within the cap. The double layer of refractory material allows for maintenance and replacement of a restorable refractory layer without disturbing or replacing the permanent refractory layer.

Abstract: A refractory system of the type having a refractory material attached to a wall by anchoring studs has a plurality of improved anchoring studs. These studs have grooves extending from the top toward the bottom of the stud and refractory material in at least some of the grooves. Preferably the grooves are parallel to one another and to a longitudinal centerline through the stud. The studs may have a smooth section on the side wall adjacent the bottom. The bottom may be conical. Spikes may be provided on the top of the stud.

Abstract: A studded wall in, or replacement panel for, a boiler or furnace has a plurality of substantially parallel tubes, each pair of adjacent tubes being connected. Separate regions of studs are attached to the wall. In each region every pair of adjacent studs is a selected distance apart, typically from one-eighth to one-half inch. The regions are configured and positioned to define a line between the regions. That line has a width different from the selected distance between the studs in the regions adjacent the line. Corrosion testing is done at selected points on the lines. The lines enable each successive test to be performed at the same locations.

Abstract: A stud of the type attached to a furnace wall or boiler tube has a plurality of projections extending from the top of the stud which act as a heat sink. The projections also have a corrosion or erosion resistant coating such as a chromium diffusion layer. The stud as well as the furnace wall or boiler tube to which they are attached will have a longer service life.

Abstract: A studded wall in, or replacement panel for, a boiler or furnace has a plurality of substantially parallel tubes, each pair of adjacent tubes being connected. Separate regions of studs are attached to the wall. In each region every pair of adjacent studs is a selected distance apart, typically from one-eighth to one-half inch. The regions are configured and positioned to define a line between the regions. That line has a width different from the selected distance between the studs in the regions adjacent the line. Corrosion testing is done at selected points on the lines. The lines enable each successive test to be performed at the same locations.

Abstract: A stud has an exterior in which a diffusion coating is provided on a portion of the stud and the remainder of the stud has no diffusion coating thereon. The uncoated portion is welded to a boiler tube or furnace wall. This stud can be diffusion coated in a retort having a layer of inert material covering a first portion of the stud and a diffusion pack mix covering a second portion of the stud. When the retort is heated a diffusion coating will form on the second portion of the stud while no diffusion layer will be formed on the portion of the stud that is covered by the inert material.

Abstract: A stud of the type attached to a furnace wall or boiler tube has a plurality of projections extending from the top of the stud which act as a heat sink. The projections also have a corrosion or erosion resistant coating such as a chromium diffusion layer. The stud as well as the furnace wall or boiler tube to which they are attached will have a longer service life.

Abstract: A refractory system of the type having a refractory material attached to a wall by anchoring studs has a plurality of improved anchoring studs. These studs have grooves extending from the top toward the bottom of the stud and refractory material in at least some of the grooves. Preferably the grooves are parallel to one another and to a longitudinal centerline through the stud. The studs may have a smooth section on the side wall adjacent the bottom. The bottom may be conical. Spikes may be provided on the top of the stud.

Abstract: Boiler tube studs of composite construction, particularly for protecting waterwall tubes in pulp mill recovery boilers. The studs include an inner solid cylindrical core of a material having thermal conductivity sufficient to provide proper heat transfer to the boiler tubes during operation, and an outer cylindrical sleeve of a material resistant to destructive conditions within a boiler during operation, such as chemical attack and abrasion. The sleeve surrounds the cylindrical surface of the core, but leaves an end surface of the core exposed. The core may be made of low carbon steel, and the sleeve of stainless steel. In order to avoid melting of the stainless steel sleeves when the studs are welded to the tubes, the cylindrical sleeves do not extend all the way to the attachment end such that axial gaps are defined where the sleeves do not cover the cylindrical surfaces of the cores.