The equipment factors affecting surface treatment are mainly reflected in the spray washing system of degreasing tank. The cleaning effect of the cleaning system is affected by the following points:
(1) Spray distance and spray angle. The distance between the nozzle and the steel strip in the degreasing tank and the spray angle between the nozzle and the steel strip are the decisive factors of the force of the spray flow on the dirt.
In Figure 4-5, a is the position before the horizontal movement speed of the jet fluid begins to decrease. At this position, the jet fluid interacts with the surface of the washing object, and the spreading area of the cleaning fluid is large, but the cleaning effect caused by the effective kinetic energy of the cleaning fluid is no longer good. The position B in Figure 4-5 is when the nozzle is very close to the washing object. At this time, the impact force of the fluid is large, but the spreading area of the cleaning solution is too small, and the overall cleaning effect is not good. And in a. There is a relatively large impact force between positions B, and a relatively large expansion area of cleaning solution also exists in position C. better cleaning effect can be achieved by placing cleaning objects in this position. D in the figure is the best position for the nozzle to spray obliquely to the surface of the cleaning object. The fouling dissociation effect of oblique jet is greater than that of vertical jet,
The relationship between cleaning distance, spraying distance, spraying angle and cleaning force is shown in Fig. 4-6. The comparison between oblique spraying and vertical spraying shows that the distance for oblique spraying to achieve the best cleaning effect is shorter than that of vertical spraying, and the decontamination effect is better than that of vertical spraying.
(2) Nozzle shape. The nozzles commonly used in spray washing system have different shapes. As shown in Figure 4-7, there are four kinds of nozzles: conical, rod-shaped, radial, etc. different shapes are suitable for different cleaning occasions. Among them, fan-shaped nozzle is most suitable for cleaning flat surface, and fan-shaped nozzle is also mostly used in color coating board unit.
(3) Tank material. The degreasing cleaning equipment is made of carbon steel without any anti-corrosion treatment, so the tank cover is easy to rust. In the repeated cycle, the rust slag turns into powder, and the equipment itself pollutes the water quality in the tank.