Page 310 - Mechanical Engineers' Handbook (Volume 4)

1 Heat Exchanger Types and Construction 299

Figure 9 Baffle types.

double segmental instead of segmental. Minimum pressure drop is obtained if baffles are
replaced by rod-type tube supports. 52

1.2 Plate-Type Heat Exchangers
Composed of a series of corrugated or embossed plates clamped between a stationary and a
movable support plate, these exchangers were originally used in the food-processing industry.
They have the advantages of low fouling rates, easy cleaning, and generally high heat-transfer
coefficients, and are becoming more frequently used in the chemical process and power
industries. They have the disadvantage that available gaskets for the plates are not compatible
with all combinations of pressure, temperature, and chemical composition. Suitability for
specific applications must be checked. The maximum operating pressure is usually consid-
3
ered to be about 1.5 MPa (220 psia). However, welded plate versions are now available for
much higher pressures. A typical plate heat exchanger is shown in Fig. 10. Welded plate
exchangers and other compact types are discussed in Section 6.

1.3 Spiral Plate Heat Exchangers
These exchangers are also becoming more widely used, despite limitations on maximum
size and maximum operating pressure. They are made by wrapping two parallel metal plates,
separated by spacers, into a spiral to form two concentric spiral passages. A schematic
example is shown in Fig. 11.