Across the chemical, oil, and gas industries, ASME pressure vessels are critical components for heating and cooling process materials. One of the key design considerations for these pressure vessels is the type of jacket used to transfer heat efficiently, maintain pressure integrity, and reduce operational costs.
Conventional Vessel Jackets
Ideal for: Small-volume pressure vessels (<300 gallons), high internal pressure.
Conventional jackets consist of an outer shell welded around part or all of the vessel to form a separate chamber for the heating or cooling medium. Baffles within the jacket guide flow and maximize heat exchange.
Benefits:
- Excellent for high-pressure differentials (vessel pressure > jacket pressure).
- Robust and well-suited for steam and high-thermal-load applications.
- Provides a high insulation value.
Dimple Vessel Jackets
Best for: Moderate-pressure applications (up to 300 psig), space-constrained designs.
Dimple jacketed vessels offer efficient heat transfer using spot-welded channels in light-gauge metal. Ideal for applications where weight, wall thickness, or external space is limited, dimple jackets provide a cost-effective solution with uniform thermal performance. Their compact profile makes them especially suitable for retrofits or tight process layouts, and they’re approved by the National Board for use up to 300 psi.
Benefits:
- Compact design with consistent heat transfer.
- Approved by the National Board for up to 300 psig.
Laser-Welded Plate Jackets (Modern Alternative)
A next-generation solution replacing traditional dimple jackets in many applications, laser-welded jackets are created by welding two stainless steel sheets in a circular pattern. A contour weld around the edge creates a sealed, pressure-tight boundary.
Once integrated into the pressure vessel or tank wall, the plates are inflated with water or nitrogen to form internal channels.
- Benefits:
- Uniform heat transfer with precision flow paths.
- Cleaner design with reduced risk of pinhole leaks.
- Flexible for flat, curved, or custom surfaces.
- Excellent for sanitary and pharmaceutical environments.
Half-Pipe Coil Jackets
Best for: High-pressure (up to 750 psig) and high-temperature processes.
Half-pipe jackets are formed by welding a split section of pipe in a spiral or serpentine pattern around the vessel shell. This design excels in processes requiring high thermal input and strong mechanical stability.
- Benefits:
- High strength-to-weight ratio.
- Allows for zoning and independent flow paths.
- Excellent drainage and maintenance access.
Surface Enhancements
In addition to jacket type, surface finish plays a critical role in pressure vessel performance. Grit blasting and polishing help optimize cleaning, reflectivity, and heat transfer. Smooth finishes are particularly valuable in clean-in-place (CIP) environments and sanitary processing.
See our Guide to Vessel Surface Enhancement.
Conclusion
Selecting the right jacket for your ASME pressure vessel involves balancing thermal needs, pressure ratings, material costs, and maintenance considerations. Traditional options like conventional, dimple, and half-pipe jackets each have their place—but laser-welded plates are redefining what’s possible in vessel design.
See our Jacket Selection Guide for more details.