1. The control parameters of plate heat exchanger are material, working pressure, design temperature, etc.
2. When selecting heat exchanger, the side with small heat transfer coefficient should get large flow rate as far as possible, and the heat transfer coefficient of both sides of the two fluid heat exchange surfaces should be equal or similar as far as possible, so as to improve the heat transfer coefficient. The temperature of the fluid heated by the heat exchanger shall be 10 ℃ lower than the saturation temperature under the outlet pressure of the heat exchanger, and shall be lower than the working temperature of the pump used for the secondary water.
3. The fluid containing silt and dirt should be filtered before entering the heat exchanger.
4. When the plate heat exchanger is selected, the flow velocity at the interface of the fluid at the side with small temperature difference shall not be too large, which shall meet the requirements of pressure drop.
5. If the flow is large and the allowable pressure drop is small, the plate type with small resistance shall be selected; otherwise, the plate type with large resistance shall be selected.
6. The detachable type or electric welding type shall be selected according to the fluid pressure and temperature.
7. It is not suitable to select plates with too small single plate area, so as to avoid too many plates, too small flow velocity between plates and low heat transfer coefficient.
8. The heat exchange medium of plate heat exchanger should not be steam.
Key points of construction and installation of plate heat exchanger:
1. The heat exchanger shall be free of deformation, and fasteners shall be free of looseness or other mechanical damage.
2. When hoisting the equipment, the lifting rope shall not be hung on the connecting pipe, positioning beam or plate.
3. Enough space shall be reserved around the heat exchanger for maintenance.
4. The inlet and outlet nozzles of hot and cold media shall be installed in the direction specified on the factory nameplate.
5. The pipes connecting the heat exchanger shall be cleaned to prevent sand, welding slag and other sundries from entering the heat exchanger and causing blockage.
6. The heat exchanger shall be subject to hydraulic test at 1.5 times of the maximum working pressure. The steam part shall not be lower than 0.3MPa of steam supply pressure; the hot water part shall not be lower than 0.4MPa.