Prolonged scale plugging causes deterioration of heat transfer conditions. The heat transfer surface of the plate heat exchanger exceeds the rated temperature or partially overheats, which may cause the heat exchanger to crack and burst and cause an accident. The energy consumption increases, and the effect of energy saving cannot be achieved. The accumulation of dirt threatens the safe operation of the heat exchanger and shortens the service life of the heat exchanger, making the heat exchanger face equipment shutdown and maintenance. In severe cases, the original heat exchanger needs to be scrapped and replaced with new equipment.
The plate heat exchanger is in use. Due to improper operation of water treatment equipment. The water quality control is not up to standard, and unqualified softened water is injected into the heating system, so that the calcium, magnesium, and carbonate in the water will be decomposed into calcium carbonate and magnesium hydroxide after being heated. A hard scale is formed. Due to the poor thermal conductivity of scale, the heat exchange efficiency of the heat exchanger is reduced and the heat energy is wasted seriously. As a result, the heating effect is affected, and the heating unit has a serious negative impact.
The plate heat exchanger is not cleaned in time, and the dirt in the water is not completely filtered, resulting in the incomplete filtering of the water from the water outlet, which is directly supplied to users. Generally, domestic hot water units are basically used for bathing. Long-term contact of unfiltered water with the skin will produce bad results and affect people's health.
Due to the large number of plates in the plate heat exchanger, it needs to be cleaned one by one and replaced with new pads. Therefore, the overall installation position is generally lifted from the installation position during overhaul, and it is disassembled and overhauled at a suitable place. When the scale on the plate is very thin and the scale layer is easily soluble in water, the plate can be placed in a special sink and scrubbed with soft fiber brown wool, or washed with 1-29cg/cmz pressure water or low-pressure steam. The use of acetylene flame heating is prohibited under any circumstances. Before maintenance, the gasket to be replaced must be carefully inspected. The surface should be smooth, consistent in thickness, free of transverse cracks, no bubbles, no gaps, no aging, no signs of overlap and butt joints. First remove the pipe, and then loosen the fixing bolts in the diagonal direction. Only after the system gas, pressure, temperature and other parameters meet the maintenance requirements, can it enter the site for construction. The adhesive used should also be within the validity period. For perforated plates, hydrogen arc welding can be used to repair and flatten. Before disassembly, the medium inlet valve should be blocked, and the high-pressure side valve should be blocked first, and then the outlet valve should be blocked, so that the heat exchanger is slowly cooled to 40°C and then discharged, then the connected pipes should be removed and the whole can be lifted off.