Bell & Gossett HT 205B SM Models ACA Straight Tube, Removable Bundle Heat Exchangers - Manual (Page 4)

c. Remove packing (G) and retaining rings (H). It may be nec-
essary to tap lightly on the retainer rings for starting their
removal. More detail of floating tube sheet is given in Illus-
tration No. 3. Illustration No. 4 shows the method of prying
retainer rings off. If tapping is necessary, be sure to tap
evenly about the circumference so the retainer ring does
not bind on the floating tube sheet.
d. Mark tube sheet (B) and shell flange for later re-alignment.
Illustration No. 5.
e. Use chain jack. One suitable is Coffing Hoist, Model MA-15
3 /
4
ton capacity. Place short piece of 4x4 hardwood (oak)
between chain of jack and floating tube sheet (E). See
Illustration No. 1. Use longer 4x4 pieces as bundle is
removed. Support the bundle by lifting or resting on the
stationary tube sheet (B), as bundle is pushed out. Illus-
tration No. 6.
CAUTION: Failure to follow the procedures mentioned
in steps 8a, b, and c may result in damage to the tubes
or tube joints leading to premature failure of the heat
exchanger.
9. Removing the tube bundle:
Refer to drawings on pages 6 and 7 giving part names of
models MEAH, OC, GC and ACA. The model MEAH tube
bundles are more difficult to remove than the other models.
The MEAH exchanger has the horizontal baffles (N) extending
from the stationary tube steel (B) to about 5 inches of the
packed floating tube sheet (E). Two rubber baffle strips (O) are
adhered to the horizontal steel baffle (N). The rubber baffle
strips seal the space between the shell and horizontal baffle,
and prevent liquid by-passing. These rubber baffle strips (O)
in the MEAH act as brakes against the shell (C) making bundle
removal more difficult.
a. If the exchanger is difficult to work upon, hoist it into the
open after disconnecting piping.
b. Remove front (A) and rear (F) heads. See Illustration No. 2.
Illustration No. 2 – Removing rear head (completely remove front and
rear heads).
Illustration No. 3 – Cross section of type “OC” Heat Exchanger showing
rear tube sheet construction. (See packing retainer detail)
Illustration No. 5 – Marking of tube sheet and shell flange.
Illustration No. 4 – Prying off retainer rings.
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