The Benefits of Dimple Jackets for Pressure Vessels

Used in a huge range of industries, from food and beverage processing to chemical and petrochemical manufacturing, fluid management is critical for ensuring smooth, efficient, and safe operations. In these applications, jacketed vessels are used for custom temperature control of containers’ contents, which may be hazardous or sensitive.

Available in a variety of different designs to meet specific application needs, jacketed vessels are used with heating and cooling media to help maintain uniform internal conditions.

Jacketed Pressure Vessel Styles

Cosmetics, pharmaceuticals, oil and gas, chemicals and petrochemicals, food, beverage, and dairy operations all have unique process system requirements. To meet these diverse needs, jacketed pressure vessels can be crafted in an assortment of styles to suit specific setups.

A standard jacketed pressure vessel is equipped with a secondary pressure enclosure, installed either on the shell or on the vessel’s dished heads. This cavity is utilized for heating and cooling via a circulating fluid, which is applied to either a portion of a tank or the full contents.

The American Society of Mechanical Engineers (ASME) approves three main styles of vessel jackets:

• Conventional Jackets, best-suited for small-volume vessels and jackets without excessive pressure. This jacket style provides a complete extra covering for either all or part of the container, creating a high-insulation enclosure with an inner and outer vessel wall.
• Dimple Jackets, offering a cost-effective solution for applications up to 300 psi. Dimple jackets are made of light-gauge metal and affixed via spot or plug welds for extra strength and durability without unnecessary additional weight. However, their one weakness is fatigue failure if subjected to rapid thermal cycling, which typically happens if the same jacket is quickly switched from a heating mode to a cooling mode or vice versa.
• Half-pipe coil Jackets, for optimal strength up to 750 psi. These jackets are excellent solutions for liquid heat transfer applications and high-temperature industrial processing. They usually entail higher manufacturing costs.
• Stayed Jackets, which offer higher pressures in the jackets as compared to a conventional jacket without inordinately increasing the required vessel thickness. They have a more robust construction against rapid thermal shocks, which can typically dramatically reduce the life-span of a dimple jacket, and thus combine the good characteristics of a conventional and a dimple jacket into one. Depending on the application, the extra cost of attaching stays can be offset against savings made in the required thickness of the inner vessel.

To ensure you choose the best vessel for your particular application, be sure to consider the specific weight, versatility, and cost-efficiency needed to ensure optimal material heating and cooling. Heat-transfer efficiency can also vary greatly from one design to another, with each style offering unique features and performance benefits.

Design Options and Common Applications for Dimple Jackets

One of the most versatile jacket styles, dimpled jackets are an excellent choice for both small and large tanks. For large applications, dimpled jackets provide a higher pressure drop at a lower price point than conventional jacket designs.

Dimpled jackets allow for large heating and cooling transfer areas at lower pressures (up to 300 psi). These jackets feature a layer of thin-gauge metal that is plug or spot welded to the vessel shell in a regular pattern. The punched and welded areas are referred to as “dimples,” which create turbulence in the jacket’s fluid flow, optimizing the heating and cooling power of the insulating fluids as they rush through the dimples.

Dimple jackets offer distinct advantages over other designs. Key benefits include:

• High jacket pressures without significant increases in structure thickness, allowing for reliable performance and optimal savings

• Excellent performance for steam applications

• Efficient heat transfer with low media flow due to the density of contact points

• Certified by Technical Standards and Safety Authority under the rules of ASME Section VIII, Rules for Construction of Pressure Vessels under Boiler and Pressure Code up to 110 psi

• Effective and economical

• Higher overall heat transfer coefficient (U)

• Superior liquid distribution

Dimple Jackets and Custom Fabrication Services from Highland Equipment

Here at Highland Equipment Inc., we’re proud to manufacture a wide range of industrial process equipment, from tanks and processors to blenders and pressure vessels. All of our equipment ensures the most reliable, efficient performance possible in sanitary and safety-critical environments.

Featuring a 2.83-inch rotated square-type pattern, our dimpled jacket, in particular, is one of the highest-efficiency jacketed vessels available on the market, and has an exceptional heat transfer coefficient.

To learn more about our dimple jacket vessels and custom design capabilities, reach out to our expert team today.