Internal Low Fin Tubes are heat exchanger tubes with fins or helical ribs formed on the inside bore of the tube while the outside surface remains smooth and plain. This is the opposite construction to an Integral Finned Tube, which carries its fin on the outside surface, and the two should not be confused when specifying a heat exchanger. Internal Low Fin Tubes are used where the resistance to heat transfer is controlled on the tube side rather than the shell side, so increasing the internal surface area and inducing turbulence inside the tube gives more benefit than adding fins to the outside. Amardeep Steel Centre manufactures Internal Low Fin Tubes in copper, copper nickel and carbon steel for oil coolers, compressor intercoolers and gas side heat exchanger applications.
Technical Data
Specifications of Internal Low Fin Tube
| Specification Feature | Standard Range / Available Options |
|---|---|
|
Product Type |
Internal Low Fin Tube (Internally Ribbed / ID Enhanced Tube) |
|
Base Tube Outer Diameter (OD) |
15.88 mm to 25.40 mm (5/8" to 1") |
|
Outer Surface Finish |
Smooth / Plain Outer Diameter (OD) |
|
Wall Thickness Under Ribs |
1.00 mm to 2.50 mm |
|
Number of Internal Ribs |
8 to 20 Internal Ribs / Helical Grooves |
|
Internal Rib Height |
0.20 mm to 0.60 mm |
|
Base Tube Materials |
Copper (UNS C12200), Admiralty Brass (UNS C44300), Aluminium Brass (UNS C68700), Cu-Ni 90/10 (UNS C70600), Carbon Steel (ASTM A179) |
|
Applicable Standards |
ASTM B75, ASTM B111, ASTM A179, ASME SB111, ASME SA179 |
|
Tube Lengths |
Straight lengths up to 8 meters (custom cut lengths available) |
|
Testing & Quality Assurance |
Internal Bore Profilometry, Hydrostatic Testing, Pneumatic Testing, Eddy Current Verification |
Chemical Compositions of Internal Low Fin Tube
| Material Grade | Specification | Cu (%) | Ni (%) | Fe (%) | Mn (%) | Zn (%) | Sn (%) | C (%) | P / S / Pb (%) |
|---|---|---|---|---|---|---|---|---|---|
|
Copper UNS C12200 |
ASTM B75 |
99.90 min |
— |
— |
— |
— |
— |
— |
P: 0.015 – 0.040 |
|
Admiralty Brass UNS C44300 |
ASTM B111 |
70.0 – 73.0 |
— |
0.06 max |
— |
Balance |
0.9 – 1.2 |
— |
Pb: 0.07 max, As: 0.02 – 0.10 |
|
Cu-Ni 90/10 UNS C70600 |
ASTM B111 |
Balance |
9.0 – 11.0 |
1.0 – 1.8 |
1.0 max |
1.0 max |
— |
— |
Pb: 0.05 max |
|
Carbon Steel ASTM A179 |
ASTM A179 |
— |
— |
Balance |
0.27 – 0.63 |
— |
— |
0.06 – 0.18 |
P: 0.035 max, S: 0.035 max |
Internal Low Fin Tube Mechanical Properties
| Material Grade | Temper / Condition | Tensile Strength, Min (MPa / ksi) | Yield Strength, Min (MPa / ksi) | Elongation in 2 in. / 50mm, Min (%) | Hardness (Max) |
|---|---|---|---|---|---|
|
Copper UNS C12200 |
Light Annealed (O61) |
205 / 30 |
62 / 9 |
40 |
65 HRF |
|
Cu-Ni 90/10 UNS C70600 |
Light Annealed (O61) |
275 / 40 |
105 / 15 |
30 |
70 HRF |
|
Carbon Steel ASTM A179 |
Soft Annealed |
325 / 47 |
180 / 26 |
35 |
72 HRB |
Equivalent Grades of Internal Low Fin Tube
| Material Description | UNS / Grade | US / ASTM Standards | EN Standards | BS Standards | DIN Standards | JIS Standards |
|---|---|---|---|---|---|---|
|
DHP Copper |
C12200 |
ASTM B75 / B111 |
Cu-DHP (CW024A) |
BS 2871 Cu106 |
DIN 1787 SF-Cu |
JIS H3300 C1220 |
|
Copper Nickel 90/10 |
C70600 |
ASTM B111 |
CuNi10Fe1Mn (CW352H) |
BS 2871 CN102 |
DIN 17664 CuNi10Fe1Mn |
JIS H3300 C7060 |
|
Low Carbon Steel |
ASTM A179 |
ASTM A179 |
P235GH (1.0345) |
BS 3602-1 |
DIN 17175 St35.8 |
JIS G3461 STB340 |
Pressure Rating Chart of Internal Low Fin Tube
| Base Material Grade | Standard Specification | Max Allowable Stress S (PSI at 100°F) | Typical Working Pressure Range (Bar)* | Max Recommended Temperature (°C / °F) |
|---|---|---|---|---|
|
Copper UNS C12200 |
ASTM B75 / B111 |
6,000 |
30 to 75 |
205°C / 400°F |
|
Cu-Ni 90/10 UNS C70600 |
ASTM B111 |
10,000 |
50 to 120 |
300°C / 572°F |
|
Carbon Steel ASTM A179 |
ASTM A179 |
13,400 |
60 to 160 |
425°C / 797°F |
Dimensions Chart of Internal Low Fin Tube
| Tube Outer Diameter (mm) | Wall Thickness Under Rib (mm) | Number of Internal Ribs | Internal Rib Height (mm) | Internal Root Bore Diameter (mm) | Internal-to-Nominal Area Ratio |
|---|---|---|---|---|---|
|
15.88 (5/8") |
1.24 |
8 |
0.25 |
13.40 |
1.35x |
|
15.88 (5/8") |
1.24 |
12 |
0.30 |
13.40 |
1.50x |
|
19.05 (3/4") |
1.24 |
10 |
0.30 |
16.57 |
1.42x |
|
19.05 (3/4") |
1.65 |
14 |
0.40 |
15.75 |
1.65x |
|
25.40 (1") |
1.65 |
12 |
0.40 |
22.10 |
1.55x |
|
25.40 (1") |
2.11 |
16 |
0.50 |
21.18 |
1.80x |
|
25.40 (1") |
2.50 |
20 |
0.60 |
20.40 |
2.10x |
Applications and Industrial Uses of Internal Low Fin Tube
- Shell-and-Tube Heat Exchangers
- Refrigeration Evaporators
- Industrial Chillers
- Oil Coolers
- Condensers and Reboilers
- HVAC Cooling Systems
- Process Fluid Heaters
- Power Plant Heat Exchangers
Frequently Asked Questions
What is an Internal Low Fin Tube?
An Internal Low Fin Tube is a heat exchanger tube with low-height fins or ribs formed on its inner surface to improve internal heat transfer.
How are Internal Low Fin Tubes manufactured?
They are typically manufactured by mechanically forming or rolling the inner tube wall to create integral internal fins.
What are Internal Low Fin Tubes used for?
They are used in heat exchangers, chillers, refrigeration systems, coolers, condensers, and other thermal equipment.
What is the difference between Internal Low Fin Tubes and Integral Low Fin Tubes?
Internal Low Fin Tubes have low-height fins formed on the inner surface, while Integral Low Fin Tubes generally refer to low fins formed directly from the tube wall. The exact terminology can vary by manufacturer and tube design.
Are Internal Low Fin Tubes suitable for heat exchangers?
Yes, they are suitable for heat exchangers where improved internal heat transfer is required.
Can Internal Low Fin Tubes be used in industrial chillers?
Yes, they can be used in industrial chillers to improve heat transfer and cooling performance.
Are Internal Low Fin Tubes used in refrigeration systems?
Yes, they are used in refrigeration systems, including evaporators and other heat transfer equipment.
How do internal fins increase fluid turbulence?
Internal fins disturb the fluid flow, increase mixing near the tube wall, and help improve heat transfer.
