What exactly is a PHE ??
hmmmm
A Plate Heat Exchanger , or PHE as it is more commonly called as , is a type of heat exchanger that uses metal plates instead of the conventional pipes as in a Shell and Tube Heat Exchanger .
It was invented by Dr. Richard Seligman way back in 1923 .
The plate heat exchanger revolutionized the concept of indirect heating or cooling of fluids .
CONSTRUCTION :
The PHE consists of metal plates which are separated by rubber gaskets . The metal plates consist of holes at it's edges to facilitate the movement of the liquid .
The above picture illustrates the construction of a traditional PHE . The RED arrows represent the flow of the fluid which is hot , while the BLUE one represents the flow of the fluid which is relatively cooler. The metal plate can be either welded or semi-welded or brazen , accordingly to the industry in which the PHE is going to be incorporated into.
In place of pipes passing through a chamber , we have metal chambers , usually thin in depth and seperated by gaskets .
Notice the flow of the liquids in the PHE , you will notice that the RED and BLUE fluid flow into alternating chambers !!! Thats the beauty of the idea !!! The gaskets are so designed as to allow the two fluids into successively alternating metal chambers , facilitating more surface area contact and thus , more heat transfer efficiency !!! BINGO !!!
Now the question why PHE when we already have shell and tube heat exchanger ??? Well , here's the complication :
Shell and Tube Heat Exchangers cannot actually perform in par when we have a low-temperature or a low-pressure application , the design of the PHE is such that it is best suited for medium and low-pressure fluids because the driving factor in the concept is surface-area !!!
" Stainless- Steel " is the most commonly used metal to manufacture the plates in a PHE because of it's high strength , high corrosion resistance and it's ability to withstand high temperatures .
There are again types of PHE :
1) PLATE AND FRAME HEAT EXCHANGER
2) PLATE AND FIN HEAT EXCHANGER
They have been classified based on the modifications done to the PHE for better feasibility in industrial processes.
ADVANTAGES :
1) High Heat Transfer Efficiency because it provides Large Surface Area
2) The thin layer ensures that the majority of the volume of the fluid flows through the plate cavities , facilitating more heat exchange
3) We can get High Degree of Turbulence at even Low Flow Rates
4) We can control the amount of heat to be transferred between the fluids by changing the distance between the plates , i.e. by changing the volume of the cavities
5) Compact , Low Cost and Easy to Clean
DISADVANTAGES :
1) Potential For Leakage
2) Blocking of gaskets can occur due to the particulate impurities present in the fluids
3) After repeated use , particles may settle down in the metal cavities , thus decreasing the effective surface area of contact between the two fluids
USES :
1) In the petroleum industry - Lube Oil Cooling
2) As effective Condensers in pharmaceutical industries
3) In Combination Boilers
4) HVAC - Heating , Ventilating & Air-Conditioning ; It is used in this technology of indoor and automotive environmental comfort .
Thats about the all important PHE guys !!!
And ya !! From today am going to keep a problem as my poll !! I will give you " ONE DAY " to solve it out and click the answer !!! In that way we can also effectively develop our mathematical prowess in the subject !!!
THANKS GUYS FOR ALL THE SUPPORT !!!
HAIL CHEMMIES !!!
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