Maintenance method of air heater

The maintenance method and process of air heater are as follows:

(1) During the overhaul or minor repair of the unit, the water side shall be cleaned and the air side shall be visually inspected. Generally, in operation, if the air temperature is 5 ℃ higher than the normal temperature due to water side blockage, it is necessary to clean.

(2) Cleaning and inspection during gun repair

① Remove the flange screws of circulating water inlet and outlet valves, and remove the connecting pipes of inlet and outlet valves.

② Remove the screws on the joint surface of the front and rear water chambers, and remove the front and rear water chambers.

③ Clean the steel pipe. Pay attention to protect the nozzle when cleaning.

④ Clean the rust and mud in the water chamber and wash it with water.

⑤ Use a scraper to repair the joint surface of the wiper chamber and the gasket residue of the flange at the inlet and outlet of the cooling water.

⑥ Check the air side tube and radiator for damage.

⑦ Check the water chamber for cracks and the diaphragm for glass damage.

⑧ Install the gasket on the joint surface. The gasket is 3-5mm rubber pad.

⑨ Brush the bolts with kerosene and coat them with black lead powder oil after drying.

10. Apply red lead antirust paint on the inner side of water chamber and water inlet and outlet pipe board.

11 check that the tube bundle of air cooler and its joints with four walls shall be tight and airtight.

(3) Hydrostatic test

① Hydrostatic test shall be conducted when the air cooler is overhauled or has leakage.

② When the pressure of circulating water reaches or approaches 0.30mpa at the zero meter level of the steam turbine, the water pressure test face can use circulating water to pass into the water side of the air cooler, and then close the water outlet valve after filling. At this time, the inlet pressure of circulating water is maintained at the water side, and the air side is tested. This test can be carried out at the same time.

③ When the pressure of circulating water at the zero meter level of the steam turbine is low, the water pressure test face can use the circulating water to enter the water, close the outlet valve, and then raise the pressure to 0.30mpa by hand pump to check whether there is air leakage at the air side. This kind of test face is only carried out in a single group of tube bundles.

④ The hydraulic test requires that the copper tube or expansion joint of the copper tube should be checked at the air side to ensure no water leakage and no water seepage, and the joint surfaces at the water side should be tight. If there is water leakage at the expansion port, it can be filled with water; if there is water leakage at the copper pipe, it should be replaced. The water pressure test shall be repeated when the copper pipe is expanded or replaced.

⑤ If the number of blocked pipes in a group of circuits exceeds 5% of the number of main pipes in the circuit, this group of tubes should be replaced.