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Quotes - Engineering - SalesU-Tube Heat Exchangers For
Tube Passes and Flow Arrangement
U-Tube Duty
A U-tube bundle is two-pass minimum. Adding partition plates to the channel makes it four, six or eight. Each additional pass sends the fluid across the bundle again through fewer tubes, so velocity rises.
Why velocity matters. Below turbulent flow the tube-side coefficient collapses, and low velocity lets particles settle and deposits build. Most liquid duty targets a velocity band that keeps flow turbulent without eroding the tube wall.
The even-pass constraint. Never forget it. Two, four, six, eight. If the duty needs a temperature cross, no pass arrangement fixes it; the shell or the rear head has to change.
Request a QuoteTube Passes and Flow Arrangement Applications
Where the Extra Pass Stops Paying
Adding passes reduces the surface area needed, which reduces exchanger cost. It also raises pressure drop, which raises pumping cost and may exceed what the system can deliver.
There is usually a clear optimum, and it is frequently at two or four passes rather than higher. If a rating comes back needing eight passes to make the duty, that is a signal to look at a different shell or a larger unit rather than to accept the pressure drop.
Selection Data We Need
Flow rate and identity of both fluids, inlet and required outlet temperatures, operating and design pressures, allowable pressure drop on each side, and any code, alloy or hygienic requirement. Fouling history, turndown range and cleaning method matter as much as the design point.
