Introduction to Atomizing Nozzle
Classification by fog flow shape
According to the shape of mist flow formed by the nozzle, the nozzle can be divided into two categories: conical solid nozzle and conical hollow nozzle. The solid nozzle is mainly used for dust suppression, and the hollow nozzle is mainly used for dust suppression.
The cone solid fog column sprayed by the solid nozzle has a high fog flow velocity, and the dust impacted by the fog particles can generally fall down. However, because of the high speed of fog flow, the air ejected around it is easy to blow away the respiratory dust with small particle size, which objectively affects the dust reduction effect. The conical fog curtain sprayed by the hollow nozzle is mainly for dust prevention. In order to increase the coverage area of the fog curtain, there is generally a large fog curtain cone angle, and the nozzle is relatively far from the dust source. This also causes that at the end of the fog curtain with large diameter, the speed of fog particles has been reduced to a very small value, and in addition to being unable to capture dust particles, it also loses its dust blocking effect.
From the shape analysis of fog body, the density of solid spray fog body is greater than that of hollow spray fog body in its full length area. In general, coal dust is difficult to pass through the fog curtain within the effective range of solid spray, so the solid cone fog body is better than the hollow cone fog body.
Classification by atomization method
(1) Mechanical atomization
Mechanical atomization mainly depends on the high-speed jet produced by liquid under the effect of pressure difference to atomize itself. Therefore, the nozzles can be divided into direct injection nozzles, centrifugal nozzles and rotary nozzles. Direct injection atomization and centrifugal atomization can be collectively referred to as pressure atomization.
The direct injection nozzle mainly relies on water injection to achieve the purpose of atomization. The water pressure requirement is relatively high, and the larger the nozzle diameter is, the thicker the atomization will be. Therefore, the nozzle diameter cannot be too large, and the flow adjustment range is relatively small. The centrifugal nozzle uses the centrifugal force generated by high-pressure water passing through the cyclone device to produce a liquid film, which is broken by air and atomized. The effect of centrifugal atomization is better than that of direct atomization, but it also requires higher water supply pressure, so the application conditions are limited.
Rotary nozzles are generally divided into rotary type and rotary nozzle type. The rotary body is divided into rotary cup type and rotary disc type. Rotating cup atomization is to spray water into the front end of the conical rotating cup, develop the water into a film with the help of the rotating cup at high speed, and atomize the liquid by the combined effect of "centrifugal force spray" and "speed spray". Similarly, the rotary disc atomization relies on the high-speed rotating disc to atomize the liquid.
(2) Medium atomization
According to different atomization methods, it can be divided into pneumatic atomization and bubble atomization. Pneumatic atomization nozzles are widely used, as shown in Figure 1. The pneumatic atomizing nozzle relies on the gas (compressed air or steam) under a certain pressure to form a high-speed airflow, which makes the air and water form a high relative speed to achieve the purpose of atomization. The utility model has the advantages that good atomization effect can be obtained under low water pressure, and the working condition can be adjusted in a large range. But the power source is not single, and the system composition is complex.
Special nozzles are usually atomized by the principles of ultrasonic, electromagnetic field and electrostatic effect. Although this type of nozzle has a good effect in other industrial applications, it is rarely used due to the harsh underground environment in coal mines.
The high-pressure atomizing nozzle has good spray effect and can achieve dust removal effect. In short, the working principle of high-pressure atomizing nozzle is to spray very small atomized particles under high pressure. It also has high pressure spraying force, which can be used to clean the cutting site. Next, let's take a look at the introduction of relevant knowledge of high-pressure atomizing nozzle.