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Fabrication Services — Heat Exchanger Fabrication

Extended Surface Heat Exchangers

Finned-tube and tube-in-plate designs that pack more heat transfer surface into a smaller, lower pressure-drop footprint — engineered for gas cooling, compressor inter/aftercooling, and process heat recovery duty.

Overview

More surface area, the same footprint

An extended surface heat exchanger adds fins — longitudinal, transverse, or helical — to the outside of a tube, or sandwiches finned plates between tube rows, to multiply the effective heat transfer area without growing the shell. The result is a compact unit that moves the same thermal duty as a much larger primary-surface shell & tube exchanger, at a fraction of the pressure drop.

Fintelius fabricates both finned-tube bundle and tube-in-plate (plate-fin) designs, with continuous plate-fin support along the full tube length for a vibration-resistant structure, and integrated moisture separation where wet gas streams demand it.

  • Longitudinal, transverse & helical finned-tube, or continuous plate-fin (tube-in-plate) construction
  • Fin density from 8 to 20 fins per inch (FPI), matched to duty and allowable pressure drop
  • Carbon steel, stainless steel, copper-nickel & admiralty tubes with aluminum or copper fins
  • Designed to ASME code, TEMA-C/B/R class, PED, Chinese CML & Korean KFR standards
Finned tube bundle — extended surface fabrication
How It Works

From gas duty to a compact, tested cooler

Every extended surface unit follows the same disciplined path through the shop.

1

Thermal & Fin Selection

Process gas duty is rated and fin type, density, and tube layout are selected to balance heat transfer against allowable pressure drop.

2

Fin-Tube or Plate-Fin Assembly

Fins are wound, extruded, or punched onto tubes — or tubes are expanded through continuous plate fins for tube-in-plate construction.

3

Bundle & Shell Fabrication

The finned bundle is assembled into its shell or housing with multi-pass tube-side configuration where required.

4

Moisture Separation & Nozzles

Integrated or external moisture separators and nozzles are fitted per the process and maintenance access requirements.

5

Testing & Dispatch

Units are pressure-tested, ASME code-stamped where specified, and prepared for shipment.

Interactive Tool

Choose your fin density

Fin density (fins per inch) is the single biggest lever on performance — drag the slider to see the trade-off.

14 FPI
Heat Transfer Surface
Pressure Drop
Fouling Resistance
14 FPI (mid-density): a balanced choice for moderately clean gas streams — good surface area gain over bare tube with a manageable pressure drop penalty and acceptable cleaning intervals.
Construction Approaches

Three ways to extend the surface

Click a construction type to see how it's built and where it's specified.

Tube-in-Plate (Plate-Fin) Construction

Tubes pass through a stack of continuous plate fins, which support the full tube length and resist vibration under high gas velocity. Fin spacing from 8 to 20 FPI is punched to the thermal design, in aluminum, coated aluminum, or copper. Integrated silicone rubber seals between passes prevent cross-mixing of inlet and outlet streams, and a built-in or external moisture separator handles condensate as gas cools below its dew point.

Typical envelope: 20″ to 120″ shell diameter, 3′ to 35′ length, 2 or 4 tube-side passes (any even number available), 3/8″ or 5/8″ tube diameter — in carbon steel, 304 stainless, admiralty, or 90/10 & 70/30 copper-nickel.

Vibration-resistant, full-length support Integrated moisture separation Compressor inter/aftercooler duty

Finned-Tube Bundle Construction

Individual tubes carry their own fins — wound, extruded, or embedded — assembled into a conventional shell-and-tube style bundle with baffles and support plates. This construction gives the most flexibility in nozzle placement and tube-side pass arrangement, and suits retrofit or replacement bundles matching an existing shell.

Materials span stainless steel, carbon steel, cupro-nickel, copper, and brass tubes with aluminum, coated aluminum, phenolic-coated aluminum, or copper fins — selected against gas composition, moisture content, and corrosion risk.

Flexible nozzle placement Retrofit & replacement friendly Wide fin/tube material matrix

Helical, Longitudinal & Transverse Fin

Fin orientation is chosen for the flow regime: helical (spiral) fins promote turbulence and are common in cross-flow gas cooling; longitudinal fins run parallel to the tube axis and suit double-pipe or annular-flow designs; transverse (circular) fins maximize surface area per unit length for cross-flow bundles in ducted or forced-draft service.

Six standard fin geometries at 16mm, 12mm & 9.5mm tube diameter (smooth or turbulent pattern) cover the majority of gas compression and process cooling duties without a custom tooling charge.

Flow-matched fin orientation Standard fin geometry library Smooth or turbulent fin pattern
Interactive Tool

Extended surface vs. primary surface

Toggle to see why extended surface wins on footprint, pressure drop, and operating cost for gas cooling duty.

Primary Surface (Bare Tube Shell & Tube)

Relative Footprint100% (baseline)
Typical Gas-Side Pressure Drop~2 psi
Condensate HandlingExternal separator required
Relative Tube Count for Same DutyHigher

Extended Surface (Finned / Plate-Fin)

Relative FootprintUp to ~40% smaller
Typical Gas-Side Pressure Drop~0.1 psi
Condensate HandlingIntegrated moisture separation available
Relative Tube Count for Same DutyLower
Why it matters: on a 25,000 SCFM gas cooling duty, cutting pressure drop from roughly 2 psi to 0.1 psi can save on the order of $50,000 per year in downstream compressor operating cost — extended surface exchangers reach the same duty in a smaller shell precisely because the fins multiply surface area without adding gas-side resistance.
Core Equipment

Shop capability behind every unit

Fin forming, tube expansion, and testing equipment sized for extended surface fabrication.

01

Fin Winding & Extrusion Lines

Helical and longitudinal fin application onto tubes across the standard fin geometry library.

02

Plate-Fin Punching & Expansion Line

Continuous plate-fin stacks punched to the required FPI and mechanically expanded onto the tube bundle.

03

Tube Bending & Layout Fabrication

Multi-pass tube-side layouts fabricated to the thermal design's flow arrangement.

04

Shell & Housing Fabrication

Cylindrical and rectangular housings fabricated in carbon steel or 304 stainless steel.

05

Moisture Separator Integration

Built-in or external moisture separator assemblies fitted for wet gas and condensing service.

06

Seal & Pass-Partition Fabrication

Silicone rubber seals and pass partitions preventing cross-contamination between tube-side passes.

07

Certified Welding Fleet

Code-qualified welders across carbon steel, stainless, and copper-alloy materials.

08

Hydrostatic Test Rigs

Pressure-test stations verifying shell and tube-side integrity before code stamping.

09

Coating & Finishing Bays

Surface preparation and protective coating applied to specification before dispatch.

Design Specifications

Capability at a glance

Construction Types
Tube-in-plate, finned-tube bundle, helical/longitudinal/transverse fin
Fin Density
8 to 20 fins per inch (FPI)
Fin Materials
Aluminum, coated aluminum, phenolic-coated aluminum, copper
Tube Materials
Carbon steel, stainless steel, admiralty, 90/10 & 70/30 copper-nickel, cupro-nickel, brass
Shell Diameter
20″ to 120″
Length
3′ to 35′
Flow Passes
2, 4, or any even number of tube-side passes
Governing Codes
ASME, TEMA Class C/B/R, PED, Chinese CML, Korean KFR
Typical Pressure Drop
As low as ~0.1 psi gas-side, vs. ~2 psi for bare tube
Delivery Format
Tested, code-stamped units ready for site installation
Quality & Testing

Verified before it leaves the shop

PT

Pressure & Leak Testing

Shell and tube-side hydrostatic testing verifies pressure-boundary integrity before dispatch.

FI

Fin Integrity Inspection

Fin bond, spacing, and surface finish inspected to the approved design package.

CS

Code Stamping & Documentation

ASME code stamping and full material traceability documentation where specified.

Applications

Where our extended surface exchangers go to work

GC

Gas Compression Inter/Aftercoolers

Centrifugal and reciprocating compressor inter/aftercoolers for large-volume air, nitrogen & process gas cooling.

OG

Oil & Gas Processing

Gas coolers, dehydration support, and solvent recovery cooling across upstream and midstream facilities.

HV

HVAC & Refrigeration

Compact cooling and dehumidifying coils for process HVAC and industrial refrigeration systems.

WH

Waste Heat Recovery & Economizers

Economizer and waste heat recovery duty where footprint and pressure drop are tightly constrained.

ST

Steam Turbine Condensers

Extended surface condensing sections for smaller turbine and process steam condensing applications.

SG

Specialty Gas Cooling

Hydrogen, oxygen, nitrogen, ammonia condensing, and biogas dehumidification service.

Need a compact, low pressure-drop gas cooler?

Send us your gas composition, flow rate, and target pressure drop for a fabrication proposal.

Request a Proposal