Transition casting for boiler with steam cooled upper furnace

A transition casting, comprising

• a first steam tube having a steam tube diameter and a steam passageway extending between a front end pointing in a forward direction and a vertical end pointing in a first vertical direction;
• a first water tube having a water tube diameter and a water passageway extending between a front end pointing in the forward direction and a vertical end pointing in a second vertical direction opposite the first vertical direction;
• a first pass-through tube having a pass-through tube diameter and a fluid conduit extending between a first vertical end pointing in the first vertical direction and a second vertical end pointing in the second vertical direction;
• and
• a membrane joining the first steam tube, the first water tube, and the first pass-through tube to form a pressure seal therebetween, wherein the first steam tube and the first water tube are located one above the other;
• wherein a center of the vertical end of the first steam tube and a center of the first vertical end of the first pass-through tube define a first line;
• wherein a center of the vertical end of the first water tube and a center of the second vertical end of the first pass-through tube define a second line;
• and
• wherein the first line and the second line form an acute angle;
• wherein the first steam tube and the first water tube do not cross over each other at a middle of the transition casting;
• and
• wherein the transition casting is one piece made by casting.

A boiler, comprising:

• an upper furnace having steam-cooled membrane walls comprising steam wall tubes;
• a lower furnace having water-cooled membrane walls comprising water wall tubes;
• and
• a transition section disposed between the upper furnace and the lower furnace, wherein the transition section comprises an upper transition casting and a lower transition casting that are joined by alternating straight water tubes and straight steam tubes;
• wherein the upper transition casting comprises
• an upper steam tube having a steam tube diameter and a steam passageway extending between a front end pointing in a forward direction and an upper end pointing in an upper vertical direction;
• an upper water tube having a water tube diameter and a water passageway extending between a front end pointing in the forward direction and a lower end pointing in a lower vertical direction;
• a steam pass-through tube having the steam tube diameter and a fluid conduit extending between an upper end pointing in the upper vertical direction and a lower end pointing in the lower vertical direction;
• and
• a membrane joining the upper steam tube, the upper water tube, and the steam pass-through tube to form a pressure seal therebetween, wherein the upper steam tube and the upper water tube are located one above the other;
• wherein a center of the upper end of the upper steam tube and a center of the upper end of the steam pass-through tube are aligned in a first plane, and a center of the lower end of the upper water tube is offset from the first plane, wherein the upper steam tube and the upper water tube do not cross over each other at a middle of the transition casting, and wherein the upper transition casting is one piece made by casting;
• wherein the lower transition casting comprises
• a lower steam tube having the steam tube diameter and a steam passageway extending between a front end pointing in the forward direction and an upper end pointing in the upper vertical direction;
• a lower water tube having the water tube diameter and a water passageway extending between a front end pointing in the forward direction and a lower end pointing in the lower vertical direction;
• a water pass-through tube having the water tube diameter and a fluid conduit extending between an upper end pointing in the upper vertical direction and a lower end pointing in the lower vertical direction;
• and
• a membrane joining the lower steam tube, the lower water tube, and the water pass-through tube to form a pressure seal therebetween, wherein the lower steam tube and the lower water tube are located one above the other;
• wherein a center of the lower end of the lower steam tube and a center of the lower end of the steam pass-through tube are aligned in a second plane, and a center of the upper end of the lower steam tube is offset from the second plane, wherein the lower steam tube and the lower water tube do not cross over each other at a middle of the transition casting, and wherein the lower transition casting is one piece made by casting.