4 jun 2013

First thinks first, what is a PHE and how it works "THE BASICS"


Plate Heat Exchanger:
Plate Heat Exchangers have a high heat transfer rate compared to other types of heat exchangers due to their large surface area. They are composed of a number of thin metal plates compressed together into a ‘plate pack’ by two pressure plates. Within a plate heat exchanger, the fluid paths alternate between plates allowing the two fluids to interact, but not mix, several times in a small area. Each plate is corrugated to increase the surface area and maximize heat transfer. Plate Heat Exchangers have a number of applications in the pharmaceutical, petrochemical, chemical, power, industrial dairy, and food & beverage industry.


Types of Plate Heat Exchangers:
There are four main types of plate heat exchangers: Gasketed, Brazed Plate, Welded, and Semi-Welded. Each type is suited for a number of applications in various industrial fields.  
Gasketed plate heat exchangers GPHE use high quality gaskets and design to seal plates together and protect against leaks. Plates can easily be removed for cleaning, expansion, or replacing purposes, drastically reducing maintenance costs.
Some Applications 
Chemical Pharmaceutical Food & Beverage Dairy HVAC Marine Oil Cooking




Brazed Plate heat exchangers are used in many industrial and refrigeration applications.
Due to stainless steel plate composition with copper brazing, they are highly resistant to corrosion.

Brazed Plate heat exchangers are efficient and compact, making them an excellent economic choice.
     Typical applications

          Refrigerant Evaporating & Condensing
          Heat Pumps
          Steam Heating
          Engine or Hydraulic Oil Cooling
          District or Zone Heating Systems
          Various Heating and Cooling Duties
          Swimming Pool Heating






Welded plate heat exchangers WPHE are similar to Gasketed plate heat exchangers, but instead the plates are welded together. They are extremely durable, and are ideal for transferring fluids with high temperatures or corrosive materials. Since the plates are welded together, mechanical cleaning of plates is not an option as with plate and frame heat exchangers.
Typical applications
Process chemicals
Oil cooling
Caustic soda
Heat transfer fluids
Hazardous liquids
Expensive fluids









Semi-Welded plate heat exchangers SWPHE feature a mixture of welded and gasketed plates. They contain pairs of two plates welded together which are then gasketed to other pairs, therefore one fluid path is welded and the other fluid path is gasketed. This results in a plate heat exchanger that is easy to service on one side and able to transfer more intense fluids on the other. Semi-Welded heat exchangers are perfect for transferring expensive materials since they have a very low risk of fluid loss.
Typical applications    
Process chemicals
Oil cooling
Caustic soda        
Heat transfer fluids
Hazardous liquids
Expensive fluids





Effective Heat Transfer:

Large surface areas and corrugated plates allow Plate heat exchangers to transfer heat very efficiently. Each plate is pressed with a chevron-shaped design to create high turblent flow, excellent fluid distribution, and to increase surface area.The fluid passages between plates can be very wide, reducing fouling rates significantly. Plate heat exchangers are ideal when transferring heat between two fluids with similar temperatures and flow rates.

Easy Maintenance:
Gasketed heat exchangers are easily disassembled and reassembled to allow for cleaning. Single plates can be removed quickly for cleaning or maintenance, minimizing the inactivity of the heat exchanger. Plate heat exchangers have a high corrosion resistance and a low fouling rate, so they do not require as much maintenance as other heat exchangers. They are also very simple to expand in order to increase flow rate or to use for another application.


Compact Design:

Plate heat exchangers are small, yet efficient. It is possible to have a Plate
exchanger with the same thermal capacity of a Shell & Tube heat exchanger five times its size. The compact design conserves space in the heat
exchanger environment, as well as material cost. Plate heat exchangers are
available in a variety of sizes and materials to suit many different applications
and industries.
Cost-efficient:
Plate heat exchangers are smaller and use less material to produce, so they
are often the most effective economic choice for a heat transfer task. Plate and gasket materials are tailored according to the desired application, so that the heat exchanger will fit design and fluid accommotions. Thanks to advanced gasket design and welded plates, plate heat exchangers also lose very little fluid; making them ideal for transferring expensive and caustic fluids. Plate exchangers can easily be expanded to suit new applications or increase flow rate, often negating the need to purchase a new heat exchanger.

Materials:
Plate heat exchangers are available in a wide variety of materials, designed to fit specific applications. Corrosion resistance and good elongation are the main issue in material decision. Plates are available in: Stainless Steel, Titanium, Titanium-Palladium, Nickel, Hastelloy, Inconel, Tantalum, SMO-254, and Incoloy 825, selected for their durability and efficient heat transfer qualities. Gaskets are available in Nitrile, EPDM, Viton, and Compressed Fiber, with Glued or Clip-on designs.
Limitations:
Plate heat exchangers are not the best choice for all applications. In situations where there is an extreme temperature difference between two fluids, it is generally more cost efficient to use a Shell & Tube heat exchanger . In a Plate heat exchanger, there can be a high pressure loss due to the large amount of turbulence created by the narrow flow channels. Applications which require a low pressure loss may want to consider a S&T heat exchanger
Gasketed Plate Heat Exchangers are limited in high fluid temperatures, by the temperature limitations of the gasket. Despite these limitations, Plate heat exchangers are the most efficient choice for a wide variety of applications.







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