Coil curvature
A curved tube can generate secondary motion across its section. The effect depends on tube diameter, coil radius, fluid properties and flow rate; a coil alone does not guarantee turbulent flow.
SHELL & COIL technology
Helical Coil Heat Exchangers
Helical coil heat exchangers, also called shell and coil heat exchangers, use removable coiled tube bundles for steam-to-water heating, process cooling and industrial heat recovery.
Working principle
How does a helical coil heat exchanger work?
One medium flows through the helical tube bundle while the second medium travels through the surrounding shell. The curved tube path provides a long heat-transfer length in a compact cylindrical body.
Shell, dished heads and coil bundle are based on the supplied HEXNOVAS CAD. Animated liquid paths illustrate flow direction; the transparent shell and tubes are viewing aids.
COIL DESIGN & DUTY SELECTION
More than a long tube in a small shell.
The coil geometry, flow distribution and maintenance arrangement must work together. Start with the operating duty, then choose the construction.
Two circuits. Heat through the tube wall.
The tube-side medium stays inside the coil. The shell-side medium occupies the space around it. A temperature difference drives heat through the metal without mixing the fluids.
Helical winding fits tube length into a cylindrical envelope. In a multi-tube bundle, the tubes share the flow; their number and length affect velocity, area and pressure loss.
Confirm the actual inlet/outlet assignment on the drawing. Steam duties also require a suitable condensate exit, rather than simply reversing a liquid-flow diagram.
Tube surface
Smooth and corrugated tubes represent different heat-transfer and pressure-loss choices. Compare both at the same duty and pumping limit. Tube profile availability must be confirmed for the selected HEXNOVAS design.
Shell-side distribution
Shell flow must reach the active tube surface. Bundle spacing, internal flow guidance and nozzle position matter alongside the tube area. Avoid treating a large shell volume as proof of good distribution.
| Duty | What determines the selection | Installation focus |
|---|---|---|
| Hot water / glycol | Design and part-load temperatures, concentration, viscosity and pressure loss on each side. | Pump capacity, insulation and vent/drain points. |
| Steam-to-water | Steam pressure at the exchanger, heating load, control range and condensate conditions. | Control valve, drainage and condensate return backpressure must be reviewed together. |
| Oil / process cooling | Viscosity at startup and operation, fouling behaviour and cooling-water availability. | Access for flushing, sampling and maintenance. |
| Heat recovery | Simultaneous source and demand profiles, target temperatures and available pumping head. | Bypass/control strategy when source temperature or flow changes. |
Design the maintenance route before the piping.
For a removable bundle, reserve its withdrawal length and lifting access. Extraction exposes external tube surfaces; it does not make a helical bore straight-through brushable. Confirm the internal cleaning method separately.
A welded non-removable exchanger needs a different service plan. A flanged pipe connection does not prove that the bundle can be extracted. Check the construction drawing and cleaning instructions.
Send your shell-side and tube-side duty →Further technical reading
Industry reference: HEXONIC JAD / JAD X and its shell-and-coil brochure. These explain another manufacturer’s construction; its model ratings, certifications and proprietary details are not HEXNOVAS specifications.
Manufacturing & quality control
From tightly formed coil to final testing.
Follow four workshop stages behind the compact shell-and-coil construction.
Forming the compact helical bundle
Corrugated tubing is wound into a compact helical bundle while the operator checks spacing and alignment.
Joining the tubes to the tubesheet
Each tube end is positioned and welded at the tubesheet to maintain separation between the tube-side and shell-side circuits.
Aligning the shell connection
The shell nozzle is aligned before welding so the connection matches the project piping arrangement.
Test-bench verification
The completed assembly is inspected and tested against the approved project procedure before release.
Why this technology
Designed around performance, integrity and serviceability.
- Long helical tube length in a compact shell
- Removable tube-bundle configuration supports inspection
- Curved flow path promotes turbulence
- Flexible stainless-steel and project-specific alloy options
Product configuration
Structure and material options.
Available configurations
- Horizontal or vertical installation
- Threaded, flanged or welded connections
- Steam-to-water and liquid-to-liquid duties
- Project-specific shell size and coil geometry
Material options
- Stainless steel 304 / 316L
- Titanium or corrosion-resistant alloys after duty review
- Project-specific shell and tube combinations
Typical applications
A compact exchanger for plant steam heating.
This vertical installation shows a shell-and-coil exchanger integrated into an industrial steam system. The cylindrical format provides a compact footprint where piping space is limited.
Plan the steam, condensate and control system together.
Confirm steam pressure at the exchanger, condensate drainage, trap selection, control-valve range and return backpressure for the actual duty.
Steam-to-water heating
District-energy interfaces
Marine and industrial utilities
Process water and heat recovery
Applications and selection resources
Selection information
What our engineers need from you.
Provide shell-side and coil-side media, temperatures, flow rates, design pressure, allowable pressure drop, materials, connection standard and installation orientation.
Frequently asked questions
Key questions before product selection.
Does a helical coil guarantee turbulent flow?
No. Flow regime and secondary motion depend on velocity, viscosity, tube diameter and coil curvature. Selection must check heat transfer together with pressure loss across the operating range.
Are all shell and coil heat exchangers removable?
No. Welded non-removable designs and removable-bundle constructions require different maintenance plans. Confirm the offered construction and access requirements on the HEXNOVAS project drawing; a connection flange alone does not establish removability.
Should I choose smooth or corrugated tubes?
Compare heat-transfer duty, available pumping head, fouling behaviour and cleaning requirements. Surface enhancement may improve mixing but must be assessed against pressure loss. Confirm available tube profiles for the selected design.
What is a helical coil heat exchanger?
A helical coil heat exchanger places a coiled tube bundle inside a surrounding shell. One medium flows through the coil and the other through the shell, creating a long heat-transfer path within a compact cylindrical body.
Is a helical coil heat exchanger the same as a shell and coil heat exchanger?
Shell and coil is the broader product description; helical coil identifies the spiral tube geometry inside the shell. This HEXNOVAS product page covers removable helical tube-bundle shell and coil exchangers.
How does a helical coil heat exchanger work?
The two fluids remain in separate shell-side and coil-side circuits. The curved coil provides a long flow path and promotes secondary flow, transferring heat through the tube wall in a compact space.
Can a helical coil heat exchanger be used for steam-to-water heating?
Yes. Steam may be assigned to the shell or coil side according to pressure, condensate drainage, control and maintenance requirements. The final arrangement is confirmed from the full operating conditions.
What data is required to size a helical coil heat exchanger?
Provide both fluids, flow rates, inlet and outlet temperatures, phase condition, operating and design pressure, allowable pressure drop, materials, connection standard, installation orientation and cleaning requirements.
Product documentation
Catalogue and technical downloads.
Use the published catalogue for product-range reference. Final dimensions, ratings and materials are confirmed for the selected model and operating duty.
Discuss this product