除了在特殊情况下的检修外，还应进行定期的维修，从而延长该产品的使用寿命。 In addition to the overhaul of the plate heat exchanger
under special circumstances, regular maintenance should be performed to extend the service life of the product. Because the heat exchanger is easy to assemble and disassemble, maintenance is simple, and special tools and equipment are generally not required. Different methods can be adopted according to different situations. So, let's take a look at the maintenance steps below!
1. Shutdown: When stopping and overhauling, the fluid valves on both sides of the heat exchanger should be closed slowly to make the pressure on both sides slowly decrease at the same time. After the residual liquid is emptied, tighten the nut. When disassembling the lever, do not proceed until the temperature has dropped to room temperature and the remaining liquid has been drained as far as possible.
2. Plate cleaning:
(1) A clean and oxide-free sheet surface is a necessary condition for ensuring tightness. When the thermal efficiency of the plate heat exchanger is significantly reduced and the pressure drop is significantly changed, the scaling is serious. The plates should be disassembled and laid flat and cleaned.
(2) When cleaning the sealing groove, lift up the washer with a screwdriver, gently remove it (or lightly bake it on the back, but avoid metal discoloration), and then tear it off. Clean the sealed tank with methyl acetone solution or other ketone organic solvents.
(3) After cleaning the plate, rinse it with water and then dry it with a clean cloth. No foreign particles or fibers on the surface of the board are allowed. The chloride ion content of the washing water is ≤25pp.
3. Check and confirm the workload After cleaning, check the plate carefully. There are three ways to check:
(1) Coloring method: check with colorant;
(2) Light transmission method: a light source is placed on one side of the plate, and a person checks on the other side;
(3) Unilateral pressure test method: test pressure to 0.35MPa (gauge pressure) on one side by water. If there is water on the other side, check the wet area of the plate quickly. We use the light transmission method for inspection. The advantages of this method are convenience and low cost. It is applicable to inspection of new and old plates.
4. Gasket sticking: Use adhesive or strong adhesive to evenly coat a layer on the bottom of the sealing groove, and then place the gasket in the sealing groove, fit evenly, pressurize, dry naturally, or heat to 100 ° C Dry at -120 ° C for two hours. Check one by one for uniform bonding and remove excess bonding 5. Assembly: The characteristics of the process combination of plate and plate heat exchangers are: if the fluid enters from the left corner hole of the plate, it always comes out from the left corner hole of the plate ,vice versa. When assembling, it is necessary to distinguish A plate and B plate correctly, that is, with the side of the plate adhesive pad as the front side, distinguish according to the direction of the deflector, and set the plate with a certain direction of the deflector as A plate, then The plate with the flow channel in the other direction is the B-plate, but there is no mark on the plate.
6. Hydrostatic test: Make four blank plates according to the size of the flange of the connection pipe, weld them at the entrance and exit, and weld the pipes on the plate to connect the compressor to the heat exchanger. Install a pressure gauge that has passed the verification and is within the validity period at the entrance and exit, and the pressure gauge range should be twice the test pressure. The test pressure is 1.5 times the working pressure.
We have learned the maintenance steps of the plate heat exchanger in detail. Only when the maintenance is performed in strict accordance with the above requirements will the quality meet the design requirements and the normal operation requirements of the product. In addition, it will save maintenance and operation costs from an economic perspective. It seems to be a cost-effective approach, after all, if there is a problem, it is very expensive to replace the new plate.