Refractory shield design for superheater tubes

Claim 1

A refractory shield for protecting a superheater tube against fluid attack comprising: a) a first partial-tube having a C-shaped cross section, the C-section having first and second ends, each end comprising an outer radial portion and an inner radial portion, each inner radial portion having a convex outer surface and extending farther than each outer radial portion to define a seat at the terminus of each outer radial portion, each inner radial portion terminating in an inner tip having an outer side; b) a second partial-tube having a C-shaped cross section, the C-shaped cross section terminating in first and second ends defining first and second outer tips, each outer tip having an inner side; wherein the outer tips of the second partial-tube oppose the seats of the first partial-tube, each end of the second partial tube has a concave inner surface corresponding to the convex inner surface of the corresponding inner radial portion of the first partial tube, and the distance between the outer sides of the inner tips of the first partial-tube is greater than the distance between the inner sides of the outer tips of the second partial-tube.