Schmidt'sche® Conventional Round-Type Transfer Line Exchangers (TLEs) are multi-tube exchangers having several double tube registers welded together to form a compact exchanger. The "tube sheets" are formed by the oval headers. This TLE configuration typically has a single gas inlet connected to multiple furnace coils. Between one and eight conventional Transfer Line Exchangers are installed on one furnace as shown in the arrangement sketch. The ends of the double tube registers are connected to the riser and downcomer manifolds. The "tube sheets" are then connected to the process gas inlet and outlet channels using specially designed flanges. The inlet channel is internally lined to protect the shell from high gas temperatures. The exchanger outlet channel is of conical or cylindrical design with the outlet nozzle flange located either on the top or on the side and connects to the downstream piping. The outlet channel is not internally insulated unless the cracked gas temperature is higher than approx. 985°F (530°C) to 1,020°F (550°C). The outlet flange is made of high resistant materials without internal insulation.

The gas inlet channel of the conventional exchanger is designed to provide uniform gas distribution, minimize residence time, gas flow recirculation and coke formation.