Pillow plate Heat Exchanger

A pillow plate heat exchanger is widely used in the dairy industry for cooling milk in large direct-expansion stainless steel bulk tanks. The pillow plate permits for cooling across nearly the whole surface region of the tank, without gaps that would happen between pipes welded to the exterior of the tank. The pillow plate in built by a slender sheet of metal spot welded to the surface of another thicker sheet of metal.

Innovative ideas and implementation

The slender plate is welded in a regular pattern of dots or with a serpentine pattern of weld lines. After welding the enclosed space is pressurized with enough force to cause the thin metal to swell out around the welds, offering a space for heat exchanger liquids to flow and creating a characteristic appearance of a swelled pillow formed out of metal. Several companies have implemented innovative projects in contemporary times.

Comparison to half tube and double jacket

In order to better understand, before forming two stainless plates are placed on each other and connected by laser welding. After the plates have been welded and formed into the final shape or vessel, the plates are hydraulically inflated using pressure by water or nitrogen; as a result bringing ellipse shaped hollow openings which can be used to conduct various heat transfer media. The pillow plate heat exchanger is an innovative concept that provides an economical alternative to traditional heat exchanger systems such as the half-tube coil and double-jacket.

Advantages of plate heat exchanger

There are many advantages when comparing to the above two types. The pillow plate heat exchanger are cheaply available are known for their lower operational costs. These are better than heat transfer and possess better control characteristics. This is more efficient in utilization of the heat transfer medium. And the factor such as the performance of existing installations can be raised without the need for additional space, makes it more advantageous. In addition the lower weight and inside the vessel maintains the primary 100% surface quality after laser welding.

The low system volume enables to accomplish turbulent flows already at low volumetric flow rates of the heat transfer medium, thus resulting in outstanding heat transfer characteristic and excellent values. And the pillow plate heat exchanger is created of mostly all stainless steels, nickel alloys and duplex materials. And this plate heat exchanger is just like any other heat exchanger, but is such case they use plates to transfer heat between two fluids.

Questions:

• What is pillow plate heat exchanger?
• State the disadvantages of pillow plate heat exchanger.