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This post was last edited by Taizi Yue on 2022-1-25 at 18:05. Here are some useful tips! Basic characteristics of ultra-fine pulverizers: Ultra-fine pulverizers, also known as hammer-blade pulverizers or aseptic pulverizers, are dynamic devices featuring a cross-shaped hammer-blade structure. They achieve pulverization through high-speed rotation that causes collisions between the hammer blades and the material, as well as between particles of the same material. These pulverizers have a simple structure, are easy to operate, offer excellent pulverization results, and have high production capacity. They are suitable for pulverizing various chemical substances, can be used for pulverizing some traditional Chinese medicines, and are also applicable to the pulverization of chemical pigments ； It features a direct connection between the motor and the hammer blade, and is equipped with dual-air-seal protection, shutdown protection in case the door cover is removed, over-temperature shutdown protection, and overload shutdown protection, making it very safe to use. The importance of rotation speed: Taking white sugar as an example, under the same conditions and using a 0.6mm sieve as well as the same grinder for the grinding experiments, the fineness of the ground sugar varies significantly depending on the rotation speed. It can be seen that there is already a noticeable difference in the grinding effect at 7200 rotations per minute compared to 6000 rotations per minute, while an extremely high rotation speed of 9000 rotations per minute enables even greater fineness in the ground product. The role of the sieve mesh: Well, aside from the impact of the hammer blade’s rotation speed on the degree of crushing, the pore size of the sieve mesh is also a key factor. We conducted another set of experiments: under the same rotation speed, using different sieve meshes resulted in significant variations in the fineness of the white sugar, but these variations were not as great as those caused by changes in rotation speed. In other words, rotation speed is the main factor affecting fineness, while the sieve mesh plays a secondary role ； At the same time, it’s not true that the finer the mesh size, the better; if the rotation speed is insufficient, the mesh has to do more work, and the consequence is a significant drop in production capacity as well as a substantial increase in the crushing time! In addition to the speed of the hammer knives and the impact of the sieve on the fineness of the crushing, the feeding method and speed are also extremely important! The feeding speed can be controlled manually or by using valves. Taking white sugar as an example, under the same rotation speed and screen conditions, feeding the material manually one time after another yields completely different results compared to feeding it at a constant rate using a screw valve ； Similarly, when crushing scorpions, we found that if the feeding speed was too high, the quality rate was only 71%; by controlling the feeding speed, the quality rate could reach 83%. The reason for heat generation during crushing: Those who are familiar with crushers will know that you’ve omitted something – namely, temperature. Indeed, a large amount of heat is released during the crushing process. If the temperature isn’t properly controlled, some materials may undergo denaturation due to excessive heat, resulting in failed quality control. In such cases, it’s impossible to increase production by keeping the machine running continuously. Therefore, to control the grinding temperature properly, it is necessary to know where the heat source for grinding comes from: 1. The heat generated by the motor’s work is transmitted to the grinding blades through the directly connected metal shaft ； 2. The transmission mechanism also generates heat, and this heat is transferred to the crushing blade through the metal shaft ； 3. Heat is generated due to the friction between the rotating crushing blade and the air. For crushing blades of the same size, different rotation speeds result in different temperatures; at 9,000 rotations per minute, the temperature can even reach 60°C. The higher the rotation speed and the larger the crushing blade, the greater its linear velocity, and thus the more heat is generated ； 4. Friction generates heat in materials, especially fibrous ones such as traditional Chinese medicines and insects. When grinding scorpions and leeches, even with a dual cooling system of air cooling and water cooling – where the water cooling uses a temperature as low as minus 40°C – if too much material is fed in, the temperature in the grinding chamber can still rise to around 50°C! Blade speed and linear velocity: Some people say that 9,000 revolutions per minute isn’t that high; we have models that reach 12,000 revolutions per minute. The crushers I mentioned earlier are those used in production, while those with 12,000 revolutions per minute are experimental or pilot-scale crushers. In other words, the size of the blades differs, and so does their linear velocity. Although 12,000 revolutions per minute seems like a high speed, the blades are smaller, resulting in a lower linear velocity. The blades used at 9,000 revolutions per minute are larger, which gives them a higher linear velocity; this leads to greater vibration, higher temperature rise, and more noise! The noise generated by crushers: Setting aside measures such as vibration damping and noise reduction, under the same conditions, for the same crusher, different rotation speeds result in significant differences in noise levels. Higher rotation speeds lead to higher noise levels, and this is an objective issue that needs to be addressed. After all, the requirements for the operating environment are becoming increasingly stringent, and high noise levels can easily cause operators to become fatigued, leading to mistakes in operation ； In addition to the characteristics of the grinder, the properties of the material itself and the requirements of the manufacturing process are also crucial factors. The properties of different materials vary greatly; some are prone to absorbing moisture and require high production capacities, such as potassium sorbate. In such cases, it is necessary to consider the sealing performance during grinding as well as the continuity of operation ； Some have high hardness; for example, calcium propionate requires 9,000 revolutions to meet the process requirements ； Some are sensitive to high temperatures; for example, white sugar, herbal extracts, and orlistat – if the temperature is not properly controlled, they will melt and oxidize during grinding, leading to sticking and adhering to the walls of the container ； Some can be ground multiple times; for example, leeches – 80% of them meet the quality standards after one grinding session, and the remaining material can be collected and ground a second time so that everything can pass through the sieve ； Some materials do not allow multiple pulverizations; for example, with scorpions, two rounds of pulverization may damage the cell walls, failing to meet the process requirements ； Some materials are clumped, which can cause the sieve to become pitted ； Some materials even contain small stones and copper wires, which requires the use of heavy-duty crushing screens; therefore, it is necessary to analyze each situation individually and design different crushing systems for various types of materials. In summary, we have analyzed and explained the application of ultra-fine powder crushers from aspects such as rotation speed, screening mesh, feeding method, temperature control, and noise. Currently, the rotation speed of ultra-fine powder crushers in the domestic market is generally around 6,000 revolutions per minute, which is sufficient to meet some market demands. However, if you are dealing with materials that require special handling or have high processing requirements, feel free to leave me a message; we can discuss this further, and it might bring you some surprises!