Plate Type Heat Exchangers

Plate Type Heat Exchangers

A plate type heat exchanger is a type of heat exchanger that uses metal plates to transfer heat between two fluids. The plate heat exchanger (PHE) is a specialized design well suited to transferring heat between medium- and low-pressure fluids. Welded, semi-welded and brazed heat exchangers are used for heat exchange between high-pressure fluids or where a more compact product is required. In place of a pipe passing through a chamber, there are instead two alternating chambers, usually thin in depth, separated at their largest surface by a corrugated metal plate.

The plates used in a plate and frame heat exchanger are obtained by one piece pressing of metal plates. Stainless steel is a commonly used metal for the plates because of its ability to withstand high temperatures, its strength, and its corrosion resistance. The plates are often spaced by rubber sealing gaskets which are cemented into a section around the edge of the plates.

The plates are pressed to form troughs at right angles to the direction of flow of the liquid which runs through the channels in the heat exchanger. These troughs are arranged so that they interlink with the other plates which forms the channel with gaps of 1.3–1.5 mm between the plates.

As compared to shell and tube heat exchangers, the temperature approach in plate heat exchangers may be as low as 1 °C whereas shell and tube heat exchangers require an approach of 5 °C or more. For the same amount of heat exchanged, the size of the plate heat exchanger is smaller; because of the large heat transfer area afforded by the plates (the large area through which heat can travel). Increase and reduction of the heat transfer area is simple in a plate heat-exchanger, through the addition or removal of plates from the stack.

PLATE TYPE HEAT EXCHANGERS CONSTRUCTION MATERIAL

TECHNICAL SPECIFICATION

1.Heat exchange surface per plate: 0,04 – 2,50 m²
2.Plate types: M6, M6-M and M6-MD
3.Max. Design pressure: 25 bar
4.Max. Design temperature: 170°C

BENIFITS OF BRAZED PLATE HEAT EXCHANGERS

*Low investment.
* Operation and maintenance costs.
* Highly efficient heat transfer (K- values on average 3-5 times higher than in case of bare-tube heat exchangers).
* Asymmetrical flow gap available for the most cost-effective solution.
* Use of smallest temperature difference

ALUMINIUM FAN

* 1.4301/AISI 304 (cost-effective in the case of uncritical media)
* 1.4539/AISI 904L (with high nickel content against stress corrosion cracking, good price/performance ratio in the case of media with the low acid and chloride content).
* 1.4529/254 SMO (higher chloride and acid – resistance than 1.4401/ AISI 316)
* Hastelloy (highly resistant against acids and chlorides, e.g. for concentrated sulphuric acid)
* Titanium ASTM B 265 * Titanium – Palladium (highest material quantity, suitable e.g. for chlorides at higher temperatures)