Channel head tubesheet

I had the front endplate on the cooling water side of the surface condenser (called the channel head cover) removed. Most of the tube inlets in the channel head tubesheet were plugged with crayfish (but in Louisiana where this story is set everyone calls these little creatures, crawfish). 

Inside the exchanger s channel head, we have the pass partition baffle, which divides the channel head into two equal portions. This baffle forces the total flow only through the bottom half of the tubes. The tubes themselves are pipes of either 3/4 or 1 in OD (outside diameter). The front end of each tube is slipped into a slightly larger hole drilled into the channel head tubesheet. This tubesheet is a disk about 2 in thick, slightly larger than the inner diameter of the shell (shell ID). 

Both the channel head cover and the channel head tubesheet (see Fig. 19.1) must be remachined to accommodate the new baffles. 

Channel head The portion of a shell-and-tube heat exchanger that covers the channel head tubesheet. 

Channel head tubesheet The fixed end of the tube bundle. 

Venting inerts from the floating head end of a horizontal reboiler can be difficult. A novel method which successfully accomplished this (232) was installing a 1-in internal pipe that extended a top tube from the channelhead tubesheet to a vent in the channel head (Fig. 15.10c). The top tube was thus converted into a "vent tube. The internal pipe was coupled to the vent from inside the channel head, to permit removal. This technique cured a CO2 corrosion problem attributed to poor venting at the floating head end. 

Primary head draining capability is provided by channel head drains. Tubesheet drains allows secondary side draining. Such drain capability enhance access for inspection and maintenance. 

Shells, Channels, Covers, Floating Heads, Tubesheets, and Flanges Pipe... 

Stationary Head Flange—Channel or Bonnet 22. Floating Tubesheet Skirt... 

FIGURE 3 Sectional view of a typical fixed tubesheet shell-and-tube heat exchanger (A) tubes (B) tubesheets (C) shell (D) tube-side channel and nozzles (E) channel cover (F) pass divider plate (G) stationary rear head (bonnet type) (H) tube support plates (or baffles). 

B) Tubesheets hold the tubes in place and provide the barrier between the tube-side fluid in the tube-side channels or head and the shell-side fluid. The tubesheet is a circular plate, thick enough to withstand any pressure difference between the two fluids and suitably drilled to accept the tubes. The tubesheets may be welded to the shell... 

---