The structure of the plate heat exchanger mainly includes plates, gaskets, compression plates (movable plates, fixed plates) and frames (upper guide rods, lower guide rods, front pillars). Plants use plate heat exchangers more and more, but the use of plate heat exchangers often encounter resistance, so how to change the resistance of plate heat exchangers.
(1) The use of heat-mixed heat exchange plates. The geometric structure of the corrugation on both sides of the thermal mixing plate is the same, and the plate is divided into a hard plate (H) and a soft plate (L) according to the angle of the herringbone corrugation.
(2) Adopt asymmetrical plate heat exchanger.
The symmetrical plate heat exchanger is composed of plates with the same corrugated geometry on both sides of the plate, forming a plate heat exchanger with equal cross-sectional areas of the cold and hot runners.
According to the heat transfer characteristics and pressure drop requirements of the cold and hot fluids, the asymmetric (unequal cross-sectional area) heat exchanger changes the wave geometry on both sides of the plate to form a plate heat exchanger with different cross-sectional areas of the cold and hot runners. The corner hole on the side of the wide runner has a larger diameter. The heat transfer coefficient of the asymmetrical plate heat exchanger decreases slightly, and the pressure drop is greatly reduced. When the flow of the cold and heat medium is relatively large, the use of an asymmetric single-process heat exchanger can reduce the plate area by 15%-30% compared to a symmetrical single-process heat exchanger.
(3)Set the bypass pipe of the plate heat exchanger. When the flow of cold and heat medium is large, a bypass pipe should be set between the inlet and outlet of the heat exchanger on the side of the large flow, so that the flow of the heat exchanger and the resistance can be reduced. In order to facilitate adjustment, a regulating valve can be installed on the bypass pipe. The countercurrent arrangement is mainly used to make the temperature of the cold medium out of the heat exchanger higher, and to ensure that the temperature of the cold medium can meet the design requirements after the heat exchanger outlet merges.