Internal Coils for Columns

Roben, Mfg., Inc. specializes in the custom engineering and fabrication of internal coils available for chemical, fine chemical, petrochemical, pharmaceutical, food and beverage, defense, and power-generation industries. Every project is designed to ASME Section VIII Division 1 (with optional Division 2), is National Board registered, complies with the European Pressure Equipment Directive (PED 2014/68/EU) for CE marking, and is registered under the Canadian Registration Number (CRN) system for all Canadian provinces.

What Internal Coils Available Are

Internal coils are heat-transfer surfaces installed inside a column or vessel to add or remove heat from the process — without requiring an external heat exchanger. Common types include pipe coils (helical or serpentine), plate-type coils, and half-pipe coils on the inside of the shell. They are widely used in reactor vessels, batch process tanks, and certain column designs.

Why Internal Coils Available Matter

Internal coils provide localized heating or cooling, eliminate piping to external exchangers, reduce footprint, and improve process responsiveness. They are common in batch reactors, jacketed-and-coiled vessels, and columns requiring intermediate heating or cooling.

Internal Coils Available — Specifications and Capabilities

Coil types: Pipe (helical, serpentine), plate-type, half-pipe

Materials: Stainless steel (304/304L, 316/316L), Hastelloy, Inconel, Monel, carbon steel

Heat-transfer fluids: Steam, hot oil (Therminol, Dowtherm), cooling water, glycol, refrigerants

Design code: ASME VIII Div. 1, with U-stamp on the coil where it is a pressure-containing component

Inspection: Hydro test, helium leak test, RT/UT of welds

Certifications and Codes

ASME Section VIII Division 1 — U-stamp

ASME Section VIII Division 2 — available on request

National Board registration — R-stamp

PED 2014/68/EU — CE marking with Notified Body coordination

CRN — registered for all Canadian provinces

NACE MR0175 / ISO 15156 — sour-service compliance

AWS D1.1 / ASME Section IX — qualified welding procedures and welders

Frequently Asked Questions About Internal Coils Available

When should I use internal coils vs. an external heat exchanger?

Internal coils are preferred when the duty is small-to-medium, when local control is needed, when piping space is limited, or when the process requires gentle, distributed heat transfer. External exchangers are preferred for large duties or high heat flux.

What are half-pipe coils and how are they used?

Half-pipe coils are pipes (typically half-round in cross-section) welded to the inside of the vessel shell, providing distributed heat transfer through the shell wall without consuming internal volume. They are common in jacketed reactor designs.

What materials does Roben Mfg. fabricate internal coils from?

Stainless steel is most common. Hastelloy, Inconel, Monel, and Alloy 20 are used when the process side is corrosive. Carbon steel is used for steam or hot-oil service when the process side does not corrode.

What is the maximum operating temperature for internal coils?

Limited by the metallurgy. Stainless coils run reliably to 800 °F. Hot-oil coils typically run to 600 °F. Steam coils up to saturation conditions for the design pressure (e.g., 600 psig saturated = 489 °F).

Are internal coils ASME code-stamped?

Yes — when the coil is a pressure-containing component, it is fabricated to ASME VIII Div. 1 with U-stamp, integrated into the vessel's manufacturer's data report.

Request a Quote on This Project

Contact Roben Mfg., Inc. to discuss your project specifications, timeline, and material requirements.

📞 (732) 364-6000 ✉ sales@robenmfg.com 📍 760 Vassar Ave, Lakewood, NJ 08701

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Internal Coils for Columns and Pressure Vessels