Reasons for nozzle damage
1. Erosion. When the liquid with high flow rate passes through the metal surface of the nozzle hole, it will erode the nozzle hole, causing the nozzle pressure to decrease and the spray state to become irregular. The probability of nozzle erosion depends on the hardness of the liquid, the spray pressure, the type of chemical used and its amount. In addition, particulate impurities in the liquid can also severely erode the nozzle.
2. Accidental damage. Improper use and untimely maintenance are the main causes of accidental damage to nozzles. Although the nozzle orifice is usually designed to be concave, the offset structure of the fan nozzle can be easily damaged.
3. Corrosion. When chemical materials are used to spray workpieces, these chemicals can also cause corrosion of the nozzle material.
4. Blocking. The build-up of chemicals and impurities on the inside or outside edges of the nozzle can cause nozzle blockage. This will affect the spray shape of the nozzle and thus the spray pressure.
5. Temperature. If the nozzle works at high temperature or abnormal temperature for a long time, it will cause the nozzle to be damaged due to the softening of the material.
Identification of Nozzle Problems
When the spray pump operates at its rated capacity, the spray pressure of the nozzle will decrease with the expansion of the nozzle hole diameter. For a damaged nozzle, even if the actual flow rate of the nozzle exceeds 30% of its rated flow, the change in atomization state is difficult to identify with the naked eye.
The way to identify a nozzle problem is to observe the pressure change on the spray pipe. When comparing different nozzles in the same pretreatment system, the location of the pressure gauge is critical. Usually the pressure gauge should be placed at the front end of the spray pipe. When judging the pressure change on the spray pipeline, the spray pressure of the intact nozzle should be used as the benchmark, and the difference between the actual pressure and the reference pressure should be used to determine whether there is a problem with the nozzle.
Troubleshooting of Nozzle Problems
Since it is difficult to directly perceive the nozzle problem with the naked eye, the selection of the nozzle is the first priority. After choosing the right nozzle, there is a complete maintenance and replacement program.
1. Regularly check the nozzle. This includes regular cleaning of the nozzle and regular inspection of the nozzle for cosmetic damage. Generally, the nozzles of the first few processes (such as pre-degreasing and degreasing) in the pre-treatment production line must be inspected and cleaned every shift, and the frequency of inspection and cleaning of the subsequent processes can be appropriately controlled.
2. Regularly replace the nozzle. The frequency of nozzle replacement depends on the environment in which it is located, the composition of the spray liquid and the material of the nozzle. If the temperature is high and the spray liquid contains impurities, the number of nozzle replacements is relatively frequent.