The open sand mill has been continuously improved in the application, focusing on solving the adaptability to high-viscosity paint slurry, reducing or eliminating air pollution and solvent loss, improving wetting and dispersibility, and adapting to small batches and multiple varieties.
1. Vertical closed sand mill
The biggest difference between the vertical closed sand mill and the open sand mill is that the top screen is moved to the upper side of the grinding cylinder, and a double-end mechanical seal box is placed at the original top screen position, so that the sand mill can be completely It is airtight and operated under a pressure not exceeding 0.3MPa, so it has the following characteristics:
a. Pressurized operation can process high-viscosity paint paste, and it is also suitable for paint paste with high thixotropy and low fluidity, so as to increase the pigment content in the paint paste and improve the dispersion efficiency;
b. Airtight operation to eliminate solvent volatilization loss and reduce environmental pollution;
c. The top sieve is not easy to skin in the round frame, which reduces the cleaning work.
2. Horizontal sand mill
The horizontal sand mill is a new product in the 1970s. Its characteristic is that the main shaft and the grinding cylinder of the sand mill are installed horizontally. The separator replaces the top sieve, which simplifies the structure and makes it easy to disassemble and wash. At the same time, the machine is also airtight. Therefore, in addition to the advantages of the above-mentioned vertical closed sand mill, it also has:
a. Large amount of sand, high grinding and dispersing efficiency,
b. Easy to disassemble, wash, load and disassemble, suitable for multi-variety production;
c, the dispersion medium is evenly distributed in the cylinder;
d. Cooling effect is good.
Especially in recent years, foreign manufacturers have improved the structure of the dynamic separator, avoiding the problem of easy sand jamming in the gap, drilling holes on the dispersion plate, increasing the return flow of the medium, and placing the dispersion plate eccentrically to increase the uniformity of dispersion. The advantages of this machine are more prominent after reducing the heat generated by grinding, reducing energy consumption, maintaining stable operation, and reducing the heat generated by grinding.
3. Double shaft sand mill
The double-shaft sand mill is equipped with two main shafts and two sets of dispersing discs in the same grinding body, which greatly improves and lowers the energy consumption.
4. Square sand mill
The square sand mill is a new type of sand mill successfully developed in Germany in recent years. Especially the grinding body is a square shape , usually two, connected in series up and down, and a motor drives the main shaft to rotate. Zirconia and silicon dioxide sintered ceramic balls with diameters of 1.0~1.6mm and 1.6~2.5mm are respectively installed in the upper and lower cylinders . It is said to have the characteristics of reasonable cylinder shape, high dispersion efficiency , small volume, convenient disassembly and cleaning, easy color change, and multiple units can be combined and connected in series.
5. Basket sand mill
The basket sand mill is a new type of sand mill developed in recent years. Unlike previous sand mills, the dispersing disc driven by the main shaft runs in a cylinder filled with grinding media. The ground slurry is transported by a mechanical pump in a flowing state from the bottom of the grinding body and overflows from the top. Instead, put the ground slurry in the mixing bucket, and put the basket equipped with grinding media and stirring knife deep into the slurry for grinding and dispersing.
