How do Plate and Frame Exchangers Work in a Hydraulic heat exchanger?

Hydraulic systems constitute the heart of modern industrial production, supplying everything from heavy construction equipment to presses. However, wherever there is power, there's heat that is not controlled. Heat is the silent death knell for hydraulic fluid seals, pumps, and seals.

Enter the Plate and Frame Heat Exchanger (PHE). This tiny, high-efficiency piece is fast replacing bulkier, older cooling techniques in hydraulic applications around the world. What is it that makes this design so efficient at sustaining an optimal oil temperature?

How the Plate and Frame Design Works

The main feature of the frame and plate heat exchanger lies in its unique structure, which maximizes its amount of surface to transfer heat in a minimal area.

1. The Components: Plates, Gaskets, and Frame

A PHE is made up of four elements that are the most important:

• The frame is an unbending structure that has a fixed plate at the end and a pressure plate that can be moved, which is held in place by bolts that tighten. The frame is used to secure plates and stop leaks.

• The Plate Pack The Plate Pack is a stack made of embossed, thin or curved metallic plates (often stainless steel) that are parallel to one another.

• Gaskets (in Gasketed PHEs): Elastomeric seals are put between each plate. They have two crucial purposes:

  • For sealing the plates and keeping the cold and hot mixture of fluids.

  • to control the flow of two fluids to create alternating channels.

2. The Counterflow Principle

1. Fluid Separation: The gaskets or brazed connections form a set of channels that are narrow channels. The hot hydraulic fluid (the fluid to be cooled) flows through each unusual channel, and coolant (typically either water or a mix of water and glycol) flows through each regular channel.

2. Contact and Turbulence The plates are adorned with chevron-like corrugations. The patterns push the liquids to form extremely turbulent counterflow routes. This turbulence continually breaks that boundary of stagnant fluid which is formed on any surface, and exposes hot, fresh oil directly to the cold plate.

3. Maximum Transfer Because the two fluids are controlled through a very thin metal plate and the flow is the opposite directions (hot oil is introduced when cooling water departs and reverses) this means that the heat transfer rate is extremely high. This permits the system to reach the very exact temperature, meaning that the coolant that is discarded is left in the exchanger only two degrees cooler than the coolant that is entering.

Key Advantages of Plate Exchangers in Hydraulic Cooling

• Superior High Thermal Efficiency:

  • PHEs are usually three to five times more productive than conventional shell-and-tube units.

  • This fast heat transfer results in cooling the hydraulic oil more quickly, while using less cooling fluid and also reducing the overall energy usage.

• Compact Footprint (Space Savings):

  • The stacked plate design allows for the highest surface area for heat transfer in the smallest volume.

  • The result is a smaller size as compared to coolers made of shell and tube that have the same capacity, making it the ideal choice for applications that require space, such as mobile devices (cranes, excavators) and small machines for industrial use.

• Easy Maintenance (Gasketed PHEs):

  • Gasketed models permit an item to be fully removed by unbolting the bolts on the frame.

  • Plates can be removed individually from the table, examined, and cleaned to prevent the possibility of fouling (sludge scale, scale, or debris buildup), making it easier to reduce time to repair and the complexity of maintenance.

• Scalability and Expandability:

  • The modular design permits simple capacity expansion by simply adding plates to the frame.

  • This means that the PHE an an investment that is able to be used in the future that is able to adapt to changes in system configurations or upgrades in cooling requirements, without requiring the complete replacement of the unit.

• Reduced Fouling and Self-Cleaning Effect:

  • A Corrugated Plate pattern creates high turbulence in the flow of fluid.

  • The turbulence helps prevent the fluid from stagnating and reduces the accumulation of mineral scale on the surface of the heat transfer, providing the appearance of a "self-cleaning" action and extending the interval between maintenance cycles.