Maintenance method of air heater

- Oct 09, 2020-

Maintenance method of air heater

During major or minor repairs, the water side should be cleaned and the air side should be visually inspected. Generally, during operation, if the air temperature is 5°C higher than the normal temperature due to blockage on the water side, cleaning is necessary.

 Cleaning and inspection during gun repair

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

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

6 Check the air side pipe and heat sink for damage.

7  Check whether there are cracks in the water chamber and whether the partitions are damaged.

8 Install the joint surface gasket. The gasket adopts 3-5mm like rubber gasket.

9  Brush the bolts with kerosene, and apply black lead powder oil after drying.

10 Coat the inside of the water chamber and the inlet and outlet pipe plates with red lead anti-rust paint.

11 Check that the air cooler tube bundle and the joints with the four walls should be tight and airtight.

Hydraulic test

1 Hydraulic test should be done when the air cooler is overhauled or leaked.

2 When the circulating water pressure reaches or approaches 0.30 MPa at the zero meter layer of the steam turbine, the hydraulic test face can use circulating water to pass into the water side of the air cooler, and close the water outlet after filling. At this time, the water side maintains the circulating water inlet pressure. Test on the air side. This kind of test can be carried out simultaneously for each group of tube bundles.

3 When the pressure of the circulating water is low at the zero meter layer of the steam turbine, the hydraulic pressure test face can use the circulating water to enter the water, close the water outlet valve, and then increase the pressure to 0.30MPa with a hand pump, and check whether there is air leakage on the air side. This face test is only performed in a single set of tubes.

4 Hydraulic test requirements, check that the copper pipe or copper pipe bulge does not leak or seep on the air side; the joint surfaces on the water side should be tight. If the expansion mouth leaks, water can be filled to make up the expansion; the copper pipe should be replaced if it leaks. Make up the expansion or replace the copper pipe to repeat the water pressure test.

5 If the number of blocked pipes in a group of loops exceeds 5% of the total number of pipes in the loop, this group of pipe bundles should be replaced.