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Quotes - Engineering - Sales| BUNDLE | SHELL SIDE | TUBE SIDE | REPLACEMENT |
| Removable or Fixed | Mechanical or chemical | Chemical or rodded | Bundle or unit |
Removable and Fixed Bundles
Which Side Can You Actually Clean
A removable bundle withdraws from the shell as one assembly, exposing the shell interior and the outside of every tube. A fixed bundle is welded into the shell and forms part of the pressure vessel, so nothing comes apart.
The consequence is cleaning access. With a removable bundle the shell side can be brushed or hydroblasted. With a fixed bundle it can only be flushed chemically, and on a deposit that chemical cleaning will not shift that is a hard limit on service life.
The other consequence is replacement economics. A shell is a simple pressure vessel with no moving parts and it frequently outlives several bundles. Where the bundle is removable, a worn-out exchanger becomes a bundle purchase rather than a capital replacement, and the nozzles, supports and pipework stay untouched.
Clearance is what makes it real. A removable bundle needs clear space in front of the unit at least equal to the bundle length, plus room to handle it. Without that, the advantage exists on the drawing and not in the plant room.
Most of the Bell & Gossett range is removable. The SU, WU, OC, HTWU, CHX, CHXS and all the tank heater bundles withdraw. That is a deliberate consequence of the U-tube geometry the ranges are built on.
Bundle Access Comparison
The decision is made at purchase and cannot be changed afterwards.
Removable
- Shell side: Mechanically cleanable
- Replacement: Bundle only
- Requires: Clearance equal to bundle length
- Ranges: Most of the catalogue
Fixed
- Lower initial cost
- Shell side chemical clean only
- Tube side rodded end to end
- Individual tubes replaceable
- Whole unit replaced eventually
Plan For
- Bundle pull clearance at layout
- Unions close to the bonnet
- Lifting arrangement
- Plugged tube tracking
- Spare gasket set on the shelf
Related
CONFIGURATION • COMPARISON
U-Tube vs Straight-Tube
The construction decision behind it.
+ Learn MoreClearance Is the Thing People Forget
Establish It at Layout, Not at Commissioning
A removable bundle needs clear space in line with the shell at least equal to the bundle length, and that space has to stay clear of pipe racks, cable trays, adjacent equipment and structural steel for the life of the installation.
It is the most commonly overlooked item in a plant room layout and the most expensive to resolve afterwards. Where the space genuinely does not exist, say so early, because a shorter larger-diameter shell or two smaller units may serve better.
Track Plugged Tubes
Every plugged tube removes surface area and shifts the flow distribution slightly. Plants routinely run past the point where the exchanger can still make its duty, because plugging is incremental and nobody is counting.
Record the count at each service. Once it reaches the low single-digit percentages of tube count, cost a replacement bundle against continued plugging.
