Views:0 Author:Site Editor Publish Time: 2020-06-19 Origin:Site
While the conventional heat transfer plate has a homogeneous corrugation pattern, the asymmetrical plate has heat transfer section divided into four quadrants, with two different angles, B1 and B2, Figure 4. The asymmetrical plate utilizes a patented invention that permits the gasket groove to be positioned in the neutral plane of the plate, recessed 50%, Figure 3.2. With the gasket groove in the neutral plane, now the distance between adjacent plates’ gasket surface and the gasket groove will always be the same regardless of the rotation of the plate. Conventional plates, with gasket groove 100% recessed, can only rotate about one axis, the Z axis.
Asymmetrical heat transfer plates are available with a high- or low - theta pattern. With these two patterns and the additional rotational degrees of freedom, it is possible to have six different channel geometries. This is double that available in conventional PH E s .
HS Channel. Two high-theta plates combined with arrowheads in
the same direction, Figure 4.1.
HD Channel. Two high-theta plates combined with arrowheads
in the opposite direction, Figure 4.2.
LS Channel. Two low-theta plates combined with arrowheads in
the same direction, Figure 4.3.
LD Channel. Two low-theta plates combined with arrowheads in
the opposite direction, Figure 4.4.
MS Channel. Combining a high- and low-theta plate with arrow
heads in the same direction, Figure 4.5.
MD Channel. Combining a high- and low-theta plate with arrowheads in the opposite direction, Figure 4.6.
Channels HD, LD and MD are identical to conventional H, L and M channels. Three new channels formed with arrowheads in the same direction have increased thermal efficiency in comparison to their counterparts with arrowheads in the opposite direction. This increase in efficiency is a result of increased turbulence of the process fluids. To form the asymmetrical channels within the plate pack, the plates are systematically rotated to achieve the desired combination of S and D channels, matching the thermal length required for each fluid.
The ability to rotate the plates relative to each other enables the design engineer to independently optimize the channel for the hot and cold fluids, matching the required thermal lengths for each fluid with that achievable by the grouping. This allows thermal duties with different hot- and cold-side thermal length requirements to be effectively handled by a PHE, no longer having exchanger designs controlled by one side or the other. The benefits of asymmetrical groupings are illustrated below, where the same conditions are used as in the previous example for conventional plates.