Operation and Maintenance Manual TABLE OF CONTENTS A. Plate Heat Exchanger Description B … (See Fig. 7) Installation The Polaris plate heat exchanger is pressure … discharge valves (or HX … A. B. Construction and Function The compact design of the Polaris PHE ( Plate Heat Exchanger) requires only a fraction of the space of a shell-and-tube heat exchanger. Both reduced heat transfer surface and lower hold-up volume mean less operating weight. Plates are manufactured in standard sizes in virtually any material that can be cold …

A. B. Construction and Function The compact design of the Polaris PHE (Plate Heat Exchanger) requires only a fraction of the space of a shell-and-tube heat exchanger. Both reduced heat transfer surface and lower hold-up volume mean less operating weight. Plates are manufactured in standard sizes in virtually any material that can be cold worked, such as stainless steels (304 and 316), titanium, Hastelloy®, and SMO-254. The gaskets serve to seal the fluids in the plate-pack and also to direct the hot and cold media into the proper flow channels. The space between the port gasket and the perimeter gasket is vented to atmosphere. This ensures that the fluids will never intermix, and that any leaks will be to the outside of the heat exchanger. (See Fig. 3) Plate Heat Exchanger Description The Polaris Plate Heat Exchanger consists of a FRAME and a PLATE PACK. The frame consists of the following: (See Fig. 1) • Fixed Head • Moveable Follower • Carrying Bar • Guiding Bar • Support Column • Tightening Bolts The plate pack is where the heat transfer takes place. It is constructed of a series of embossed, gasketed metal plates. The plates are gasketed so that the hot and cold media flow in a parallel fashion across alternating channels. (See Fig. 2) The pack is custom-designed to the exact requirements of the heat transfer application. Fig. 3 Fig. 2 Fig. 1
Plate Characteristics The Polaris plate is designed to obtain the maximum possible heat transfer efficiency. Each plate is embossed (pressed) with a “V-shaped” herringbone pattern. The “V’s” always point in opposite directions on adjacent plates. This creates a large number of contact points between the plates which in turn enables the plate pack to withstand high pressures with relatively thin (0.5-0.8 mm) plate materials. In order to more closely match the exact requirements of the application, Polaris plates are manufactured in both short and long thermal lengths. This is accomplished by varying the angle of the “V’s” in the herringbone pattern. The “long” plate features a relatively flat “V” pattern which produces extremely high turbulence and high heat transfer at the expense of higher pressure drop. The “short” plate features a more steeply-angled “V” pattern with correspondingly lower heat transfer and pressure drop. The two plate types may also be mixed to produce an intermediate result. (See Fig. 5) Polaris heat exchangers use the parallel flow pattern. Fluid in a circuit enters and exits on the same side of the heat exchanger. This means that the plates may be used as either left or right plates simply by turning them 180?. As shown, fluid runs from port 1 to port 4 and from port 3 to port 2. (See Fig. 6) The fluids enter the PHE through connections on the frame. A single-pass arrangement has all four connections on the fixed head. This design is preferred, where possible, because the unit may be opened for maintenance or expansion without breaking the pipe connections. For “close-approach” applications, a multi- pass unit may be required. This arrangement puts connections on both the fixed head and the moveable follower. (See Fig. 4) The most common flow pattern is called counter current, where the fluid inlets are on opposite ends of the fixed head. The co-current flow pattern is rarely used, but may be a good solution in some special cases.

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