Alfa Laval CB27-50M Tamrotor NT5306 Aftercooler Plate Exchanger

Alfa Laval CB27-50M Tamrotor NT5306 After Cooler Brazed Plate Heat Exchanger

The Alfa Laval CB27-50M (Tamrotor OEM Ref: NT5306) is a high-efficiency, copper-brazed plate heat exchanger (BPHE) engineered specifically for demanding compressed air aftercooling and thermal transfer applications. Designed for integration within Tamrotor / Gardner Denver screw compressor packages and marine auxiliary machinery, this unit rapidly extracts heat from discharge air to bring operating temperatures down toward ambient dew point.

Manufactured with 50 corrugated AISI 316 (EN 1.4401) acid-resistant stainless steel plates vacuum-brazed with pure copper, the CB27-50M delivers a compact footprint, superior thermal conductance, and high resistance to cyclic thermal shock and vibration.

Model Details

• Manufacturer: Alfa Laval
• OEM Equipment Partner: Tamrotor / Gardner Denver Marine
• Model Code: CB27-50M
• Tamrotor Part Number (MPN): NT5306
• Alfa Laval Part Number: 32361-8250-1
• Channel Configuration: M-channel (Medium theta corrugation pattern for balanced pressure drop and heat transfer coefficients)
• Number of Thermal Plates: 50

Technical Details

Features

1. High-Turbulence Plate Corrugation: The asymmetrical M-channel design induces high Reynolds numbers at low fluid velocities, maintaining thermal performance while resisting particulate fouling.
2. Gasket-Free Vacuum Construction: Plates are bonded in an inert vacuum furnace with 100% copper filler, eliminating elastomer seal degradation, external leakage paths, and gasket maintenance routines.
3. Extreme Mechanical Integrity: Rated up to 31 bar design pressure and tested up to 46.5 bar, providing surge capacity against pneumatic hammer and pump transients.
4. Compact Power Density: Provides up to 85% volumetric reduction compared to conventional shell-and-tube aftercoolers while matching thermal dissipation.
5. Corrosion-Resistant Fluid Paths: 316-grade stainless steel surfaces protect against acidic moisture condensates found in heavy-duty compressed air streams.

Compatibility

• Tamrotor Screw Compressors: Marine and industrial screw units using aftercooler module NT5306.
• TMC (Tamrotor Marine Compressors): Shipboard working air and control air skids.
• Gardner Denver Compressors: Rotary screw packages requiring secondary fluid heat rejection.
• General Industrial Utility: Closed-loop glycol chillers, hydraulic oil return cooling, and compressed nitrogen aftercooling.

Part Number Cross-References

• Tamrotor OEM: NT5306 / NT-5306
• Alfa Laval Base Code: CB27-50M
• Alfa Laval Catalog MPN: 32361-8250-1
• Interchangeable Alternate Forms: CB27-50H (Higher shear/pressure drop), CB27-50L (Lower pressure drop)

Applications

• Compressed air intercooling and aftercooling in rotary screw packages.
• Marine engine room control air systems and service air drying stages.
• Hydraulic power unit (HPU) oil cooling via freshwater loops.
• Closed-loop chiller evaporators, condensers, and economizers.
• Industrial process heat recovery and vacuum system heat dissipation.

Frequently Asked Questions

What causes an aftercooler like the Alfa Laval CB27-50M to lose cooling performance?

Performance drops typically stem from two root issues: biological scaling or mineral buildup on the water side (reducing thermal transfer coefficients) and oil sludge accumulation on the compressed air side from failing compressor separators. Routine back-flushing with an approved mild cleaning solution restores original heat exchange ratings.

Can the CB27-50M be used with sea water / marine raw cooling water?

Standard CB27 units utilize pure copper brazing material. For marine compressor installations, they are designed to run on the central fresh water (LT-FW) cooling circuit. Direct open seawater exposure can cause dezincification and galvanic pitting of the copper braze fillets over time; an intermediate closed cooling circuit or titanium/nickel-brazed model is recommended if raw seawater is the primary coolant.

How do I distinguish between M, H, and L plate channels on Alfa Laval CB27 models?

The letter suffix identifies the plate corrugation chevron angle. The “H” model has an obtuse angle offering high thermal efficiency at the expense of higher pressure drops. The “L” model has an acute angle yielding low pressure drop but lower heat transfer. The “M” configuration features a balanced chevron combination that delivers moderate pressure resistance and optimized heat exchange, making it suited for rotary screw compressor air channels.

What is the primary indicator of an internal plate rupture?

An internal failure between circuits manifests as water carryover into the compressed air system (filling downstream receivers and air dryers) or, conversely, compressed air blowing back into the machinery cooling water header, causing air locks and cooling water expansion tank overflows. Hydrostatic differential testing isolates this issue immediately.

Is the Alfa Laval CB27-50M serviceable or repairable if leaking?

Because the unit is a vacuum-brazed single-block assembly, individual plates cannot be removed or re-gasketed. If an internal breach between circuits or external braze failure occurs, the unit must be replaced as a complete assembly. Regular strainer maintenance and adherence to operating pressures ensure operational lifetimes exceeding 10 years.