Page 300 - Fluid mechanics, heat transfer, and mass transfer

HEAT EXCHANGERS 281

Different tube-to-tube joints.
FIGURE 10.10

Different types of expansion joints.
FIGURE 10.11

shell side is the hottest, the maximum is typically leaks could occur at the tube sheets, either the shell or
85 C. tube side fluid will collect in the space between both

& Usually if an expansion joint is required, it is because tube sheets. It is unlikely that both tube sheets will
the maximum allowable tube compressive stress has leak simultaneously.
been exceeded. According to the TEMA procedure
for evaluating this stress, the compressive stress is a
strong function of the unsupported tube span. This is
normally twice the baffle spacing.
. What is a double tube sheet design? When is it used?
Illustrate.
& If mixing of the shell side and tube side fluids cannot
be tolerated, the double tube sheet design, shown in
Figure 10.13, is used for extra protection. Because

Illustration showing shell expansion joint. FIGURE 10.13 Double tube sheet design.
FIGURE 10.12