Hairpin heat exchangers utilize true counter-current flow. Unlike multi-pass shell-and-tube designs where correction factors are used to account for inefficiencies resulting from co-current passes, this process maximizes temperature differences between shellside and tubeside fluids. When a process calls for a temperature cross (hot fluid outlet temperature is below cold fluid outlet temperature), a hairpin heat exchanger is the most efficient design, with fewer sections and less surface area. Double-pipe heat exchangers utilize a single pipe-within-a-pipe design and are commonly used for high fouling services such as slurries where abrasive materials are present, and for smaller duties. Standard shell diameters range from 2” (50,8 mm.) to 6” (152,4 mm.). Multi-tube heat exchangers are used for larger duties with standard designs for shell diameters up to 30” (762 mm.) and surface areas in excess of 10,000 ft2 (930 m2) per section. BROWN FINTUBE® range of products includes a variety of unique enhancement devices for different process conditions.
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The free-floating U-tube bundle compensates for the differential shell-tube expansion and eliminates the need for expansion joints or packed joints commonly used in shell & tube type heat exchangers. Large radius U-bends are easily cleaned with flexible shaft tube cleaners.
The mechanical advantage
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Our separated-head closure uses independent tubeside and shellside flanges, bolting and gasketing. This closure is used for moderate pressures up to 1,300 psi (92 kg/cm2), cyclic service, high temperature differences, and/or for temperatures below -20°F (-28.8°C) or greater than 650°F (343°C).
Our TAPER-LOK® closure is typically used for high pressure up to 15,000 psi (1055 kg/cm2) applications. Like our separated-head, the TAPER-LOK® closure uses separate tubeside and shellside flanges, bolting, and gasketing. The unique feature this closure offers is a reusable TAPER-LOK® ring which acts as a self-energizing seal. TAPER-LOK® is the registered trademark of Taper-Lok Corporation. Koch Heat Transfer Company has an exclusive license for TAPER-LOK® closures for use in double-pipe and multi-tube hairpin heat exchangers.
The LOK-FLANGE® closure uses common through-bolting with independent gaskets and is typically used for design pressures below 1,000 psi (70 kg/cm2). The center flange of this closure is threaded, which allows removal of the tube-end flange for inspection and cleaning of the tubes while maintaining pressure on the shellside. This closure allows the maximum number of tubes in a given shell diameter.
The ZR CLOSURE™ closure is the newest addition to the BROWN FINTUBE® family of closures. This closure bridges the gap between the separate-head and the LOK-FLANGE® closure by providing separate tubeside and shellside flanging and bolting, while retaining the maximum number of tubes in a given shell diameter.
This closure is a conservative through-bolted design. When the bonnet is removed, the U-bends of the tubes are completely exposed to permit full field inspection.

Our closure designs provide an effective means of providing a removable tube bundle for a variety of design conditions and applications. All of our closures have the following features:

Operation and maintenance manuals are available that address the disassembly and reassembly of specific designs. In general, the bundle of a hairpin exchanger is removed by first removing the tubeside bolting, flanges and split rings. The next step is to remove the shellside bolting, flanges and split rings. Finally, the return bonnet bolting is removed and the bonnet is placed to the side. The tube element can now be pulled from the back end of the shell by placing a sling around the U-bends. On larger multitubes, a plate is installed around the U-bend for proper sling placement. Assembly is performed by reversing the process and utilizing new gaskets.
Replacement parts for BROWN FINTUBE® or BAS-TEX exchangers are readily available. One complete set of gaskets is recommended for one year’s operation.
For facilities with numerous hairpin exchangers, Koch Heat Transfer Company will perform a survey of the facility and establish design equivalents to current BROWN FINTUBE® models. We will also evaluate ways to establish common designs for multiple services to allow commonality of spare parts and elements, resulting in reduced spare parts inventories and maintenance. Please contact a Koch Heat Transfer Company sales representative for more details.
ALCO Products™ has been a leader in the hairpin heat exchanger industry and has solved the industry's most demanding heat transfer problems. The ALCO™ designs -Double-Pipe & Multi-Tube - with either bare or longitudinally finned tubes, will provide you with the most economical solution for your heat transfer applications.
Ideal Applications For ALCO™ Hairpin Heat Exchangers:
Non-removable
Removable

Detachable U-bend cover for access to removable tubes.
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