Custom Double Pipe Heat Exchanger Design & Manufacture

Safe Professional Innovative

High-integrity thermal solutions for small duties, extreme pressure differentials, and space-critical installations. Graham Hart Process Technology provides bespoke double pipe (concentric) heat exchangers engineered for pure counter-current flow and maximum thermal efficiency.

Graham Hart Process Technology specializes in the design and manufacture of high-performance double pipe heat exchangers (also known as hairpin or concentric pipe exchangers). These units are the ideal choice when conventional shell and tube designs are uneconomical or space is at a premium. By utilizing a single tube mounted within another, they achieve true counter-current flow, enabling superior temperature crosses and reliable performance in high-pressure or low-flow applications.

What is a Double Pipe Heat Exchanger?

A double pipe heat exchanger consists of a small-diameter pipe mounted concentrically inside a larger-diameter pipe. One process fluid flows through the inner pipe (tubeside), while the second fluid flows through the annular space between the two pipes (shellside). This "hairpin" configuration is specifically engineered for duties that require a large temperature change in a compact footprint.

Manufacturing of High-Integrity Heat Exchangers

When should you choose a Double Pipe Heat Exchanger over Shell and Tube?

Double pipe heat exchangers come into their own when process duties involve low flow rates, large temperature crosses, or extreme pressure differences. Because of their small diameter, they can handle higher pressures with thinner walls than conventional shell and tube units, making them more cost-effective for high-pressure service. They are also the preferred solution for pilot plants and sites where modularity and ease of maintenance are critical.

Technical Specifications & Capabilities

Feature	Specification / Capability
Design Codes	PD 5500, EN 13445, ASME VIII, TEMA
Design Standards	TEMA, API 661
Flow Configuration	Pure Counter-Current (allows for temperature crosses), Co-Current (for precise control).
Pressure Range	Ultra-High Pressure to Full Vacuum
Mounting Options	Vertical or Horizontal; Series or Parallel banks
Material Options	Carbon Stee, Stainless Steel, Duplex, Titanium, Hastelloy, and Exotic Alloys

The Graham Hart Process Technology Difference

The challenge with small-scale thermal duties is that a standard shell and tube unit is often over-engineered, bulky, and thermally inefficient for low flow rates. Furthermore, achieving a "temperature cross"—where the cold fluid outlet is hotter than the hot fluid outlet—is physically impossible in many traditional designs.

At Graham Hart Process Technology, we bridge this gap with precision-engineered double pipe solutions. By thermal modelling, we ensure that your unit is optimized for pure counter-current heat transfer. Our "inside-out" mechanical design allows the unit to handle high cyclic temperature variations without the need for expansion bellows, as the inner pipe is free to expand. Whether you are processing high-viscosity fluids in a refinery or managing safety-critical cooling in a nuclear facility, our double pipe exchangers provide a robust, maintainable, and space-saving solution.

Frequently Asked Questions

Can double pipe heat exchangers handle temperature crosses?

Yes. Unlike many other configurations, the pure counter-current flow of a double pipe exchanger allows the cold fluid to be heated above the exit temperature of the hot fluid. This makes them ideal for heat recovery applications where maximum energy transfer is required.

How are double pipe heat exchangers cleaned?

Graham Hart Process Technology designs these units with flanged connections, allowing them to be completely stripped down. This provides full mechanical access to both the inner pipe and the outer annulus, making them highly suitable for high-fouling fluids that require periodic manual cleaning.

Are double pipe exchangers suitable for high-pressure gas?

Absolutely. Their small diameter allows for high-pressure integrity with significantly lower material thickness compared to larger vessels. We frequently supply these for high-pressure gas processing and hydrogen service where safety and leak-prevention are paramount.

Optimise Your Process Efficiency

Request a Technical Quotation or Download the Double Pipe Data Sheet

Related Products

Multi-Tube Hairpin Heat Exchanger Design & Manufacture

Graham Hart Process Technology specialises in Multi-Tube Hairpin Heat Exchangers, often referred to as "multis." These units utilise a U-tube bundle within separate shells for each leg, achieving true counter-current flow. This design is specifically engineered to handle significant "temperature crosses" and thermal expansion without the need for expansion bellows, making them the premier choice for high-pressure, high-temperature, and cyclic industrial services.

Find out more