| 摘要 |
Feedwater preheater for heating feedwater in the form of steam turbine condensate by means of condensing extraction steam from a turbine, includes a casing, a fixed tube plate and a movable tube plate disposed opposite one another in the casing, feedwater inlet and outlet chambers located adjacent the fixed tube plate, a feedwater reversing chamber disposed in the casing and partly defined by the movable tube plate, a first group of feedwater conducting tubes connected at one end thereof through the fixed tube plate to the feedwater inlet chamber and at the other end through the movable tube plate to the reversing chamber, a second group of tubes connected at one end thereof through the movable tube plate to the reversing chamber and at the other end thereof through the fixed tube plate to the feedwater outlet chamber, a steam vessel disposed in the casing and surrounding the second group of tubes, the first group of tubes, on the one hand, and the second group of tubes, on the other hand, being mutually spaced apart a distance so great that stresses produced by varying thermal expansion of the tubes which, in turn, produce a tipping movement and deformation of the movable tube plate do not exceed a permissible value. |
