Common faults and solutions for plate heat exchanger maintenance_
Common failures and solutions for plate heat exchanger maintenance
906, as an energy-saving equipment, sometimes causes problems like this due to improper use. We can analyze and deal with some simple faults by ourselves. Below, Diguang Heat Transfer will analyze and summarize the maintenance of the lower plate heat exchanger. Common faults and solutions. 1. Common problems of plate heat exchangers are: 1. Plate heat exchanger liquid leakage 2. Plate heat exchanger leakage 3. Plate heat exchanger pressure drop is too large 4. Plate heat exchanger heating temperature can not meet the requirements Let me explain the reasons and solutions for the above problems one by one. Causes of liquid leakage in the plate heat exchanger: due to improper selection of plate material, cracks or perforations due to plate corrosion, and operating conditions that do not meet the design requirements; residual stress after cold stamping of the plate and the clamping size during assembly is too small Stress corrosion caused by; slight leakage at the plate leakage groove, causing the harmful substances in the medium to concentrate and corrode the plates, forming a string of liquid. The treatment method of the liquid flow is: replace the cracked and perforated plate, use the light transmission method to find the crack of the plate on the spot; adjust the corresponding operating parameters to meet the design conditions; the clamping size of the plate heat exchanger should be in accordance with the repair and assembly Requirements are not as small as possible. Causes of external leakage of the plate heat exchanger: the clamping size is not in place, the size of each place is uneven (the size of each place should not be greater than 3mm) or the clamping bolt is loose; the sealing gasket of the part is out of the sealing groove, and the main sealing surface of the sealing gasket There is dirt, the sealing gasket is damaged or the gasket is aging; the plate is deformed, and the assembly misalignment causes the running pad; there are cracks in the plate sealing groove or the second sealing area. Plate heat exchanger leakage treatment method: under no pressure, re-clamp the equipment according to the clamping size provided by the manufacturer, the size should be uniform, and the deviation of the compacted size should not be greater than plus or minus 0.2N (mm) (N Is the total number of plates), the equality between the two compression plates should be kept within 2mm; mark the leakage parts, and then disassemble the heat exchanger to investigate and solve them one by one, reassemble or replace the gaskets and plates; Repair or replace the deformed part of the plate. When there is no spare part for the plate, the deformed part can be temporarily removed and reassembled for use; when reassembling the disassembled plate, the surface of the plate should be cleaned to prevent dirt from adhering to The sealing surface of the gasket. The reason for the excessive pressure drop of the plate heat exchanger: the pipeline of the operating system is not normally purged, especially when many dirt such as welding slag in the pipeline of the newly installed system enter the inside of the plate heat exchanger, due to the abortion of the plate heat exchanger The cross-sectional area is relatively narrow, and the frequent and suspended matter in the heat exchanger gathers at the corner holes and the diversion area, which causes the flow channel area to be greatly reduced, causing the main pressure loss in some parts; the plate heat exchanger is the first time The area is too small during model selection, resulting in excessively high flow velocity between the plates and a large pressure drop; after a period of operation of the plate heat exchanger, the pressure drop is too large due to fouling on the plate surface. Treatment method of excessive pressure drop of plate heat exchanger: remove dirt or waste residue or fouling in the flow channel of plate heat exchanger. For each new operation household, clean it once a week according to the actual situation or set a fixed setting according to the application. Clean at intervals of time; the secondary circulating water adopts soft water after softened water treatment. Generally, the quality of suspended solids in the water should not be greater than 5mg/L, the diameter of impurities should not be greater than 3mm, and the pH should be greater than or equal to 7; when the water temperature is not greater than 95 degrees , The concentration of Ca and Mg should not be greater than 2mmol/L; when the water temperature is greater than 95℃, the concentration of Ca and Mg should not be greater than 0.3mmol/L, and the mass concentration of dissolved oxygen should not be greater than 0.1mg/L; for central heating systems, it can be Adopt the method of replenishing water once to twice. The heat supply temperature of the plate heat exchanger cannot meet the requirements. The reasons: insufficient medium flow on the primary side, resulting in a large temperature difference on the hot side and small pressure drop; low temperature on the cold side, and low temperature at the cold and hot ends; multiple plate heat exchangers operating in parallel The flow distribution of the heat exchanger is uneven; the internal scale of the heat exchanger is serious. The treatment method that the temperature of the plate heat exchanger cannot meet the requirements: increase the flow rate of the heat source or increase the diameter of the heat source medium pipeline; balance the flow of multiple plate heat exchangers operating in parallel; disassemble the plate heat exchanger to clean the surface of the plate fouling .