There is no doubt that the pressureless three product dense medium cyclone is the most widely used equipment in the coal preparation field, with simple structure and high separation accuracy. Especially, the best choice for the separation of fine coal is also mature in engineering application. On the other hand, its application effects in different projects are quite different, such as power consumption per ton of coal, dielectric consumption, lower limit of sorting, medium coal with fine, medium coal with gangue, etc. Similarly, there is no systematic analysis of the laws behind this, which also troubles everyone. At the same time, some people also called for saying: "The level of re mediation theory is seriously lagging behind." I really think so. After a long period of thinking and practice, I recently had an epiphany (or a superficial understanding) about it and shared it with my friends in coal preparation.

In the article "Non Negligible Demineralizer Water Spray", we draw a conclusion that "the water spray volume of the demineralizer nozzle is only related to the pressure at the nozzle and the diameter of the nozzle, but not to the performance of the circulating water pipeline and the circulating water pump". In other words, on the premise that the nozzle specification is determined, the water spraying amount is only related to the pressure, and each pressure has a uniquely determined flow corresponding to it.

The same theory is extended to the three product cyclone. On the premise that the specifications of the three product hydrocyclone are fixed, each feeding pressure has a certain amount of medium circulation, which is independent of the performance of the medium mixing pump. The three product cyclone is equivalent to a "nozzle" of another shape ". In this way, each specification of three product dense medium cyclone has a unique determined H-Q curve, just like the H-Q curve of the pump. With the H-Q curve, we can query the precise circulation volume of the cyclone and the medium distribution ratio of each discharge outlet under a certain pressure. Under the condition that the medium quality at each discharge outlet is determined, there is a relatively determined range of the amount of materials that can pass through, which actually corresponds to the best Composition of feeding float and sink.

Summarize and explain:

1. Each specification of hydrocyclone has a determined H-Q curve, which is independent of the performance of the medium mixing pump.

2. Different hydrocyclones of different specifications have different H~Q curves, that is, the corresponding medium distribution proportion is different, that is, the suitable feed floating and sinking composition is also different. (The H~Q curves of conventional hydrocyclone and super hydrocyclone must be different.)

3. If we can get the H~Q curve through experiments, we can make the design more accurate by checking the H~Q curve, or find out the problem quickly and accurately during production.

4. The specifications of hydrocyclones are relatively certain, and the number is small. Through tests and similar principles, we can get all the H-Q curves of hydrocyclones with specifications.

5. For hydrocyclones of the same specification, the pressure is the only factor determining the medium circulation volume. However, different media density will affect the distribution ratio of media at each outlet and the separation density of the first and second sections. Considering two limit cases, when pure water and high-density suspension are pumped into the same cyclone, the response of pressure drop loss in the cyclone to the feed pressure is different.

6. With the H~Q curve of a hydrocyclone of a certain specification under different medium densities, we can query the circulating volume of the medium, the distribution ratio of the medium, and the separation density of the first and second sections under a certain pressure, so as to judge the raw coal processing capacity composed of specific floatation and sedimentation.

This is my staged understanding, and I hope it can enlighten you.