Dimple jacket

Laser-welded dimple jacket integrated into process or bulk vessels

We have experience to fit jacketed vessel for over 40 years, specializing in dimple jacketed tanks and reactor plates for process, storage vessels, and pressure vessels. Our vessels utilize thermal heat exchange surfaces to control the temperature and quality of the contents inside.

Jacketed vessels are common in various industries. The surfaces of these vessels can be designed to either heat up or cool down the contents. They may be utilized to remove excess heat generated during a reaction (heat reactor vessel) or decrease the thickness of highly viscous fluids.

Dimple plate jackets and homogeneous tempering

Based on process analysis, it has been proven that enclosing the product completely with a dimple jacket as the heat transfer surface provides the most homogeneous tempering. This results in more favorable temperature differences and better efficiency compared to compact external thermal heat exchangers. Such treatment is particularly gentle on products, especially beverages.

Dimple plate jackets, compressive strength and scratchfree inner tank surface walls

Laser-welded pillow plate jackets are primarily utilized as process tank plates, particularly in milk tanks, wine tanks, beer tanks, reactor vessels, and pharmaceutical vessels. They are also commonly used in vessels for warming up and cooling in the food industry or cylinders for solvent recovery. However, when it comes to warming up or maintaining a constant temperature in melting vessels for waxes or fats, double-wall vessels have had issues due to the strength of their jackets.

Our single embossed dimple plates have already been deformed and rolled with 100 bar. They have the advantage of providing compressive strength while also ensuring a smooth and scratch-free interior for the inner tank wall.

Pillow plate jacketed vessels surface and quality benefit

The surface of the vessel has a large dimple jacket which helps control the temperature of the product during various process steps. This design also allows for safe and homogeneous temperature control. By using this method, a separate thermal process stage may not be needed, which can lead to increased productivity and better quality products.

Vessels that are made using laser-welded dimple jackets have less weight due to the reduced use of stainless steel material. This also results in vessels being manufactured at a lower cost while maintaining a high product quality.

Dimple jacketed method of operation

Single embossed dimple jackets consist of two metal sheets of different thickness welded together using laser or resistance welding. Fluid channels are created between the metal sheets by a unique inflation process. These channels, along with the fittings such as pipes with welded, flanges, or threaded socket ends, create a pressure chamber. The chamber is used to transfer heat to or from a room as a fluid passes through it. The Single embossed laser-welded dimple jacket surrounds this chamber. If the Laser-welded dimple jacket chamber is under pressure (more than 0.5 bar above ambient) or vacuum, this has been taken into account during the design process.

Pillow Plate integration into operation

Our process vessels have single embossed dimple jackets that function for both cooling and warming up. These jackets are customizable in terms of material, shape, and size, making them suitable for various industries. Additionally, they can be retrofitted to vessels already existing by rolling them into a cylindrical half-jacket that clamps onto the vessel or by welding them into rings to construct a new pressure vessel.

How to manufacture a dimple jacket?

Inflation and dimple plate profiles

Vessels are constructed using laser-welded panels, without any blown-up profiles. The flow profile of the heat exchange panels will be created after the vessel has been built. The laser welding process does not cause any damage to the later dimple plate vessel or pressure vessel inside. In modern times, surface treatments are unnecessary and various shapes of cuts for pipes can be accommodated. A closed-loop heating system for a vessel with a jacket provides a lot of convenience in batching processes. It is common for certain industries to require a vessel to undergo both heating and cooling in a single process. Utilizing a well-designed jacket with a thermal fluid system is a smooth way to accomplish the necessary temperature changes.

Connection to process of dimple jackets

To prevent damage to the plate connections, it is important to lay the connecting pipe work to the laser-welded dimple jacket in a manner that can handle tensions arising from thermal and mechanical expansion. In addition, suitable supports need to be used to bear the weight of the connecting pipe work. If expansion bends and/or expansion joints are not included in the delivery, we suggest that you use them. Proper welding procedures should be followed and checked for any connection seams that need to be welded to the connections. This recommendation is provided in accordance with valid and authorized welding procedures.

Single embossed pillow plate standard connection version

There are two versions of the embossed dimple plate. The standard version includes a butt-welded tube to the inner metal sheet. The reinforced version includes a crown that is welded to the base metal sheet, and then the tube is welded to the crown. To connect the fluid to the laser-welded dimple jacket, you can use flanges, welding nozzles, or screw pipe connections. It's important to follow the projected flow direction for the heat transfer fluid.

Pillow plate screw connection version

For screw connections, it's necessary to retighten them while the equipment is running after a certain period. The heat exchange plates are not electrically connected and, if the design does not already provide a venting facility for the plates during liquid operation of the laser-welded dimple jacket, one should be arranged above the upper piping. If the design of the plates did not include an oil removal device and the refrigeration process requires it, then one should be installed through the lower pipe for the laser-welded dimple jacket to function properly with refrigerants.

Dimple jacket advantages in comparison to half pipe or double wall manufacturing of process vessels

To build process and bulk vessels, there are three primary options: dimple jackets, double shell, and hilf pipe manufacturing. Laser-welded dimple jacket plates are more efficient and homogenous compared to the double-jacket design or welded-on half-pipe coils that only cover half of the surface. Laser-welded dimple plates occupy the entire surface and require less volume, allowing for thinner tank wall thicknesses.

Therefore, we should not explore the option of double shell any further when comparing prices of the three alternatives, as its wall thickness is too high compared to competitive pricing. In terms of cost, the process of welding a half pipe can be more than twice as expensive as laser-welded dimple jacket execution. The main factors driving up manufacturing costs for half pipes are their thicker walls and longer welding times.

Assembly of Laser-welded dimple jackets

Our laser-welded dimple single embossed jacket heat exchange plates can be delivered either inflated or not inflated. Not inflated means they have not been inflated yet. If you choose to inflate the fluid channels yourself, we can provide assistance with the important steps.

Embossed dimple plates, either single or double, can be used for cylindrical or rectangular vessels. Single plates can be welded into the tank, functioning as the pressure-approved tank wall, and customized to fit complicated tank shapes. Double plates can be clamped onto existing vessels, with improved heat transfer possible through the use of heat transfer cement.

How is the single embossed dimple plate supplied to the customer?

I. As weld-im element

1. Component for a cylindrical shell

1.1. Delivered as a flat laser-welded dimple plate
The customer provides the necessary information about tank size, inner jacket wall thickness, pressure, medium in outer jacket space, and flow rate. Refrigeration AG designs and produces the dimple plates for the tank based on this information, including channel layouts, connections, and pressure drops. The company creates custom drawings and manufactures the dimple plates using a laser welding machine. The plates are shipped in a flat condition.

1.2. Complete dimple plate components
Refrigeration AG is responsible for rolling, inflating, pressure testing, and fitting tubes to the dimple plate jacket manufactured by Heat Transfer Technology AG. Additionally, component parts for conical dimple plate bottoms are available in English language code (EN-GB). No new details or facts were added.

2.1. Delivered as a flat laser-welded dimple plate bottom
Refrigeration AG provides flat laser-welded dimple plates that are cut into the required shape.

2.2. Complete conical dimple plate bottoms
If customers require it, we can provide conical dimple plate bottoms with a certification as a finished and approved component.

3. Component parts for dimple plate dished ends

3.1. Complete dimple plate dished heads
We can provide customers with finished dimple plate dished ends, including a double shell and certificate, if requested. These dimple plate dished ends are produced under special requirements and undergo laser welding to become a complete component part.

What is the customer’s procedure to manufacture the tank?
The manufacturer can process laser-welded components in the same way as standard metal sheets. However, the laser-welded dimple plates must be rolled according to Refrigeration AG regulations. All the laser-welded shell sections, bottoms, and top ends must be welded together to complete the tank. After welding is complete, the inflation of the laser-welded metal sheets must be carried out following Refrigeration AG's guidelines. Once this is done, the necessary tubes can be welded onto the tank.

It is possible to add single embossed dimple plates to any vessels without the need for welding or approved vessels. These plates can be attached using tension strips as only contact points or stay bolts with clamping links. For optimum heat transfer, it is recommended to use a suitable BUCOmastic between the dimple plate jacket and the tank wall. Existing tanks retroactively.

Certifications of dimple jackets

Our company has developed, constructed and experimented with pressure equipment in the form of laser-welded dimple jacket heat exchange plates. These plates are accompanied by a works certificate and can also be certified with CE labeling and a declaration of conformity if mandated by the European Pressure Equipment Directive 97/23/EC. We can provide additional certificates upon request. Our delivery includes information about the design, size, connections and approved operational parameters. The language used in our communication is English (United Kingdom).

Pillow Plate: Why is it cheaper to produce than a Shell & Tube?

Laser-welded dimple jacket advantages

  • Our jacketed vessels provide efficient heat transfer and minimal pressure drop, without needing costly double shells or half pipe construction. Customized spot spacing.

  • Our dimpled jacket tank are lightweight and made with thin metal sheets, leading to lower production and material costs. Less stainless steel material in use.

  • Our laser-welding process prevents any surface damage on the inside of the tank, so expensive grinding or polishing isn't necessary.

  • Our pillow plates are perfect for achieving homogenous and conciliatory tempering of products for numerous industries.

  • The materials are chosen individually to ensure a long lifetime for manufactured vessels.

  • Welding contours of the plates can be freely programmed, allowing for any design to be created according to your application needs with flexible use for easier welding.

  • We offer a range of kinds of weldings for pillow plates, cut-outs for pipes and legs, and even integration into vessels for both mechanical and thermal functions.

  • Using our pillow plates means you will need smaller quantities of refrigerant as cooling media or heating medium for heating steps due to their small volume and safe process control.

  • If you have vessels in place already, we also offer clamp-on plates as dimpled jackets.

  • Our products are highly reliable for process tank cooling in many industries.

Pillow Plate technical data

  • We manufacture large sizes up to 14000 x 2000 mm, as well as one-piece cylinders with diameters ranging from 600 to 3800 mm as normal standard for all kind of dimple jacket specifications.

  • Our dimple jackets are suitable for both conical and elliptical pressure vessel heads, and can withstand up to 50 bar operating pressure by a special inflation process.

  • We create a dimple jacketed vessel for pressure vessels with wall thicknesses between 0.8 and 1.5 mm, featuring dimpled plates on the outer side with customized channels form.

  • For dimple jacketed pressure vessels, we also offer groundplates up to 12 mm with single embossed dimple plate profiles on the inner side.

Pillow Plate specifications

  • We offer a dimple jacket design suitable for water, glycol, thermal oil, or steam inside the vessel.

  • Our tank cooling dimple jacket vessels are available in the form of dimple plates, compatible with all refrigerants.

  • Our experienced engineers can design the pillow height channel of the dimple jacket according to your individual calculations.

  • We offer dimple jackets made from carbon steel or stainless steel, including AISI 304, AISI 316L, AISI 316Ti, and titanium.

  • Our dimple jackets are available with stained, ground, or polished surfaces.

  • We provide certificates according to TÜV, PED, TR CU (GOST), and ASME standards.

Pillow Plate applications and benefits

Homogenious tempering of liquids in process tanks. Such as in milk tanks, wine tanks, beer tanks, reactor vessels and pharmaceutical tanks.

For over 50 years BUCO tank plates and pressure vessel walls.