One end of the tube plates at both ends of the floating head heat exchanger is not connected with the shell, which is called floating head. When the pipe is heated, the tube bundle and floating head can freely expand and contract along the axial direction, thus completely eliminating the temperature difference stress.

The floating head end structure of a novel floating head heat exchanger comprises a cylinder, a cover side flange, a floating head tube plate, a shackle, a floating head cover, a cover, a screw hole, a steel ring and the like, and is characterized in that a concave or trapezoidal sealing surface is arranged on the inner side of the cover side flange, and a plurality of screws are drilled or welded on the outer side close to the sealing surface so as to be evenly distributed; the shackle and related parts are eliminated at the floating head, and the sealing groove of the floating head tube plate is the original groove, which is the same. Drilling holes between concave and trapezoidal grooves, evenly penetrating or welding a plurality of screws, setting the floating head flange as a double seal with convex and trapezoidal bosses, and setting a wide flange with the same end face, wherein the convex, trapezoidal bosses and partition plates are respectively matched with the concave, trapezoidal grooves and partition plates of the floating head tubesheet, the floating head flange and the flangeless spherical head are welded into a floating head cover, and flange screw holes are matched with screw holes or screws of the floating head tubesheet. Fasten and compress the concave, trapezoidal groove, butt groove and gasket of the floating head tubesheet with bolts or nuts. If necessary, the structure can appropriately increase the thickness and diameter of the floating head tubesheet and the inner diameter of the cylinder, and at the same time change and increase the dimensions of related parts accordingly. In addition, there is also an auxiliary steel ring which is free from external force, and the inner diameter of the steel ring is larger than the outer diameter of the floating head tube plate. One end of the steel ring is connected and sealed with the concave or trapezoidal sealing surface on the inner side of the cover flange, and the other end is sealed with the original groove of the floating head tubesheet and its gasket or excircle through the flange or other structures.

Characteristics of floating head heat exchanger;

One end of the tube sheet of the floating head heat exchanger is fixed between the shell and the tube box, and the other end of the tube sheet can move freely in the shell, which can be seen in the field. The shell and tube bundle of this heat exchanger have free thermal expansion, and the tube bundle can be drawn out, which is convenient for cleaning between tubes and inside tubes. Its disadvantages are complex structure, high cost (20% higher than that of fixed tubesheet), leakage at floating head during operation, and difficulty in inspection and treatment. Floating-head heat exchanger is suitable for large temperature difference between shell side and tube bundle or easy scaling of shell side medium.