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Quotes - Engineering - SalesHelical Tube Design
A plain copper tube transfers heat well enough; a helical tube transfers more of it in the same length.
IPAC's water-cooled aftercoolers use a patented helical extended-surface tube: a copper tube formed with a continuous spiral that increases the surface area on both sides and breaks up the boundary layer of air inside it. The spiral keeps the compressed air turbulent along the full length of the tube, where a plain tube lets it settle into a smooth, insulating film at the wall. The result is more heat transferred per foot, which is how the 51 Series fits 4,785 SCFM into a 51 inch shell.
Helical or Plain?
Decided by what is in the air and the water.
- Clean air, clean water: helical - smallest unit for the duty
- Oil carry-over from a lubricated compressor: plain tube
- Fouling cooling water: plain tube, removable bundle
- Replacement bundle: match the original tube type
The Water Side, and the Cost
The same geometry works on the water side, where the spiral ridges disturb the shell-side flow across the bundle. The cost is a slightly higher pressure drop than a plain tube of the same bore - the catalogue holds the air-side drop under 2 PSI on average - and a tube that is cleaned by flushing rather than rodding. Where the compressed air carries carry-over oil or the cooling water is heavily fouling, a plain-tube bundle, often removable, is the better specification and is offered on the same shells.
Tube Materials
Both tube types are supplied in copper as standard and in stainless steel, admiralty brass or 90/10 copper-nickel where the water demands it. The tube type does not change the model number; state it at the time of order or read it from the original order record when replacing a bundle.
| RANGE | TYPE | COVERS | RATING |
| Water-Cooled 51 Series | Water-Cooled Aftercooler | Fifteen shell and tube models from 38 to 4,785 SCFM, all 51-1/8 inches long | 200 PSIG (300 PSIG small NPT units) |
| Water-Cooled 59 Series | Water-Cooled Aftercooler | Nineteen close-approach models from 37 to 11,970 SCFM, all 59 inches long | 200 PSIG (300 PSIG small NPT units) |
Common FAQs
No - the spiral stops a rod. They are cleaned by flushing or chemically. Where the air carries oil or the water fouls heavily, specify the plain-tube bundle, which can be rodded and is offered on the same shells.
No. W0110 is W0110 with either tube. State the tube type at the time of order or read it from the original purchase record when replacing a bundle.
The spiral keeps the compressed air turbulent along the full tube length, breaking up the insulating boundary layer at the wall, and it adds surface on both sides. More heat moves per foot of tube, so the shell is shorter for the duty.
Related Pages
Water-Cooled 51 Series
Fifteen shell and tube models from 38 to 4,785 SCFM, all 51-1/8 inches long.
READ
Water-Cooled 59 Series
Nineteen close-approach models from 37 to 11,970 SCFM, all 59 inches long.
READ
Fixed vs Removable Bundles
The difference between a fixed bundle (F) and a removable bundle (R) in an IPAC water-cooled aftercooler, and how to choose between them.
READ
