The spiral plate heat exchanger is divided into a detachable spiral plate heat exchanger and an inseparable spiral plate heat exchanger. The structure of the irremovable spiral plate heat exchanger is relatively simple, and both ends of the spiral channel are welded. Except for the sealing structure at both ends of the spiral channel spiral plate heat exchanger, the other is the same as the non-detachable type. For the purpose of mechanical cleaning, the removable spiral channel is open at one end and sealed with a flat plate cover and gasket to prevent fluid from leaking into the atmosphere or a short circuit in the same channel. In order to improve the pressure bearing capacity of the spiral plate, it is supported by a distance column between the plate and the plate. There are two types of fluid inlet and outlet on the cylinder: normal and tangential. In China, tangential joints are generally used. Its fluid resistance is small and impurities are easily washed out. The use of rotary bearings is relatively convenient, allowing the heat exchanger to stand upright or horizontally. The heat exchange A and B fluids flow through the two sides of the spiral plate respectively. One of the fluids flows from the outside to the inside along the spiral channel to the center outlet. The other fluid enters the center along the spiral channel and flows out from the inside. . Both fluids flow in pure countercurrent flow. The maximum structural dimensions of the spiral plate heat exchanger are: plate width 1800 mm, outer diameter 1700 mm, heat transfer area 250 m2, and plate-to-plate distance 20 mm. Maximum operating pressure up to 2.5 MPa is allowed. The operating temperature is determined by the materials used, most of which are carbon steel, stainless steel, aluminum, copper and titanium.
Three ways to choose a heat exchanger:
1, The plate type or corrugated type should be determined according to the actual needs of the heat exchange application. In the case of a large allowable pressure drop for the flow rate, a plate type with a small resistance should be used, and a plate type with a large resistance should be used instead. According to fluid pressure and temperature conditions, make sure to choose removable or brazed. When determining the plate type, it is not appropriate to select the plate with a small plate area, so as to avoid excessive plates, small flow velocity between plates, and low heat transfer coefficient. Attention should be paid to the larger heat exchangers.
2, Regarding the design and selection of plate heat exchangers, there are certain requirements for pressure drop under normal circumstances, so it should be checked. If the check pressure drop exceeds the allowable pressure drop, design calculations must be re-calculated until the process requirements are met.
3, Heat exchanger flow refers to a set of parallel flow channels in the same direction of flow of a medium in a plate heat exchanger, and the flow channel refers to a medium flow channel formed by two adjacent plates in a plate heat exchanger. In general, several channels are connected in parallel or in series to form different combinations of cold and hot media channels. The type of flow combination should be calculated based on the heat exchange and fluid resistance, and determined under the requirements of the process conditions. Try to make the convection heat transfer coefficient in the cold and hot water flow channels equal or close to each other, so as to obtain a good heat transfer effect. Although the flow rate between the plates of the plate heat exchanger is not equal, the average flow rate is still used to calculate the heat exchange and fluid resistance.
