As for the overhaul of ammonia evaporator, let's give a brief introduction today. The main faults of the ammonia evaporator are: oil and dirt sticks in one pipe block the pipe; cracks or needle-shaped holes in the outside of the second pipe due to rust and other factors.
If the oil and mechanical impurities in the evaporator mix and the viscosity is high, the pipeline should be blocked first by hot ammonia defrosting, if defrosting can not solve the problem, the evaporator should be pumped a thousand net ammonia, and then 0.6 MPa (surface pressure) compressed air blowing off. If you blow it, you will not solve the problem. Explain that some blockage, such as wooden plug, abrasive cloth and cotton yarn used for cleaning pipe fittings, has been left in the pipe fittings.
This kind of situation should generally be cut off. But in order to reduce the number of roots in the pipe. The obstruction in the tube should be found. The blockage can be found according to the frosting condition before and after the tube and the liquid flow sound in the pipe. Find the obstruction, cut off the pipe fittings, take out the obstruction, and then weld the pipe fittings, after pressure test to find the leakage qualified before resuming the use of the evaporator.
Two, plugging the leak
If there is leakage for evaporation drain pipe, such as in smooth wall pipe or pipe jacking, needle-shaped hole, should be welded. If the production task is busy, can not immediately weld repair, used to plug the leak in the rubber plate, with pipe jam, until production off-season welding treatment. If the finned tube of the air cooler leaks, the treatment method should be to close the inlet valve and the air return valve of the air cooler, open the hot ammonia defrosting return valve and the total defrosting return valve, use the circulating barrel or the discharging barrel to evacuate, and open the defrosting water at the same time to increase its pressure, so as to pump quickly and cleanly. Do not use the method of opening the return valve to evacuate, this method of evacuation time is long, and ammonia is difficult to clean clumsily. After the equipment is evacuated, the relevant connections can be dismantled and connected to the atmosphere and welded or welded by electric welding or gas welding.
Some equipment because the valve internal leakage, can not be pumped, but can be pumped below atmospheric pressure, then can use a sharp punch to punch the pin-shaped hole, not to leakage ammonia outside, can be welded. The service life of the equipment is less than s years, and the pipe fittings without serious corrosion can be treated like this, in the treatment must be welded with electric welding can not be repaired with gas welding.