Pillowplates | Dimple Jackets

By Keppels Laser Welding

    Keppels Pillowplates and Dimple Jackets

    • Pillowplate laser welding
    • Pillowplate products
    • Pillowplate complete applications
    • Pillowplate specials

    Pillow plate laser welding

    Generally 98% of the pillowplate material is stainless steel, 304L up to 254SMO.

    Pillowplates can be designed with thin top plates for the applicable working pressure. For instance with 1.0 mm plate we can reach a burst pressure of 180 bar. With 2.5 mm we can design heat exchanger plates with burst pressures of 400 – 500 bars.

    The working pressure global guideline:

    • Water / glycol / thermal oil: 1 – 5 bar
    • Refrigerant Freon – NH3: 19 bar (at 20oC)
    • CO2 refrigerant: 120 bar
    • Steam: 0.5 – < 30 bar

    The maximum product size depends on the width of the laser welding machine. Products larger than 2000 x 2000 mm should be divided into a maximum machine width of 2000 mm. Thickness of the pillowplate, base plate + top plate can be 30 mm.

    Pillowplate products

    Laser welded flat plates, to be processed in your factory.

    Inflated pillowplate, ready to be used in your application

    Pillowplate complete applications

    Falling Film Water chillers (Freon, CO2)

    Ice banks

    Bulk Solid Heat Exchangers BSHE

    Pillowplate specials

    • Pillowplate pipes diameter 100+ mm
    • Copper and titanium pillowplates
    • Satellite simulation plates
    • Cryogenic plates
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    Laser-welded pillow plate stainless steel
    Inflated pillow plate heat exchanger
    Detail inflated pillow plate pillow
    Pillow plate weld pattern before inflation

    The applicable pressure code will have a safety factor on the working pressure.

    Knowing the working/design pressure, the following step is the test pressure that will be 1.3-1.5 times the design pressure. Than inflation pressure must be declared, to be on the safe side during testing of the pillowplate, the inflation pressure should be 30 to 50% above the test pressure. This is to prevent deforming of the pillowplates again when putting the test pressure on the plates. To safely inflate the pillowplate to the inflating pressure the burst pressure of the pillowplate should be 30% or more above the inflation pressure.

    Example:

    • Working pressure 10 bar
    • Design Pressure code 15 bar
    • Test pressure 15 – 18 bar
    • Inflation pressure 30 bar
    • Burst pressure 50 – 60 bar

    The working and test pressure should never come above the inflating pressure !!!! This will cause unpredicatable deformation of the pillowplate. Also burst of the plate is possible if inflated towards the burstpressure.

    With this burst pressure, the heat exchanger application, the pillowplate thickness is chosen with a application corresponding laser welding pattern, 0.8 – 1.0 – 1.2 – 1.5 – 2.0 are the normal plate thicknesses.

    The application gives a global indication for the pillowplate thickness [mm], or the plate thickness for the application:

    • 0.6 Solar collectors
    • 0.8 Milk tanks (BMC), Plate registers
    • 1.0 – 2.0 All applications (Tanks, wine plates, Falling Film Chillers, Ice banks)
    • 1.2 – 1.5 Steam / Thermal oil

    Design of pillowplates.

    The working pressure with the top plate defines the pillowplate pattern. After a sketch the CAD drawing is made. With this CAD drawing the machine laser welds the pillowplate. In the production is the final product made and the pillowplate inflated.