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The
standard shell and tube graphite heat exchangers comprises a
steel shell enclosing a graphite tube bundle fitted with end
covers.
Because
of the differences in their coefficients of thermal expansion,
(steel expands 2-3 times as much as graphite) the differential
expansion between the steel shell and the graphite parts is
taken up by the externally packed floating tube sheet. This compensate
expansion and contraction of the shell over the tube bundle.
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The
graphite tube bundle is held in the shell by the stud holding
the fixed tube sheet to the fixed end shell flange. These bolts
remain in place to ensure that the tube bundle is restrained whenever
the exchanger is in service, or subjected to pressure testing,
or whenever the exchanger is moved. The fixed end cover is fixed
to the fixed tube sheet by the stud between the pressure plate
and the fixed end shell flange. The
floating end cover is held against the floating tube sheet by
the stud between the pressure plate and the floating tube
sheet
flange. This flange holds a split ring, which is located in
the groove in the floating tube sheet. Floating Head Sliding
Gland seals the shell and floating tube sheet employing a stuffing
box.
Specification:
Shell-and-tube graphite heat exchangers are
constructed from the following components:
- Three
kind of graphite tubes: Pressing Extrusion Tube, Impregnated
Tube, Carbon Fiber Reinforcement Tube on request.
- Graphite
tube with or without carbon fiber reinforcement in standard
dimensions of 22/32, 25/37 and 36/50 mm
- Standard
graphite tube lengths up to 6 m
- Two tube
sheets--one fixed and the other floating, relative to the
shell
- Large
heat transfer areas (over 1,000 m2)
On this basis, shell and tube graphite heat
exchangers are used as heaters, coolers, condensers, falling
film coolers, evaporators and absorbers.
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