Cylindrical grinding machine (I) Classification and working principle of cylindrical mills The specifications of cylindrical mills (referred to as mills) are expressed in the cylinder (straight) diameter and inner length (degree) dimensions. Although the types of mills are different, in general, the basic principles of crushing materials during grinding are similar. In short, when the mill rotates at a certain speed, the grinding medium such as steel balls (rods) or ore (gravel) loaded into the cylinder, the friction between the cylinder liner and the grinding medium The force, the gravity of the grinding medium, and the centrifugal force generated by the rotation of the mill will be lifted to a certain height as the cylinder moves upward, and then the gravity of the grinding medium (actually gravity) When the radial component is greater than or equal to the centrifugal force, it begins to detach from the inner wall of the cylinder and descends according to a certain trajectory. This recurring movement produces a continuous impact and grinding action to comminute the material. The cylinder is the basic component of the ball mill for grinding work. End caps 2 and 6 are fitted at both ends of the barrel, and a hollow journal on the end cap is supported on the main bearing 7. The discharge end of the cylinder is provided with a drainage grid plate 4. The large ring gear 5 is fixed to the cylinder. A flange is welded to both ends of the cylinder, and is respectively coupled to the flanges of the end caps at both ends. In order to facilitate the internal maintenance and installation of the lining of the mill, 1~2 holes are opened on the cylinder. The volute feeder (Fig. 4) is also fixed to the hollow journal of the ball mill feed end and rotates with the mill; it has a spiral shaped spoon that can be used to shovel the material in the tank into the spoon. The material enters the hollow journal through a circular hole in the side wall at the bottom of the spoon. The tip of the spoon is made of wear-resistant material and can be replaced with a spoon head. The material is mostly high manganese steel or alloy steel. The ore feeder can shovel and lift the slurry (or sand return) in the ore tank from the axis position below the ball mill and feed it into the ball mill. [next] The combined feeder (Fig. 5) is a collection of drum and volute feeders; it combines the functions of the above two types of ore feeders and is a kind of ore feeding device commonly used in closed-circuit grinding operations. [next] Cylindrical mills such as rod mills, ball mills, tube mills and self -grinding mills are characterized by heavy loads, low rotational speeds, and large starting torques. The transmissions are determined according to these characteristics. Figure 6 shows the transmission of a conventional cylindrical mill. [next] Hops Gun,Hop Gun 100L,Hop Gun For Beer Brewery,Brewery Hop Gun Dongguan Deao Food Equipment Co.,Ltd , https://www.craftbrewtech.com
There are many types of mills widely used in industrial production, and the classification methods are also different. Some are classified according to the shape of the grinding medium, some are classified according to the shape of the cylinder, some are classified according to the method of discharging, and some are classified according to the method of grinding production. 
[next]
The motion characteristics of the grinding media play a decisive role in the grinding process. The height of the grinding medium and the shape of the falling motion mainly depend on factors such as the structure of the mill, the rotational speed, the shape of the surface of the lining and the filling rate of the medium, etc., and may be in a state of sloping, throwing, pulsating or centrifugal ( image 3).
(2) Ball mill The ball mill mainly has two types of grid type and overflow type, which can be used for dry grinding or wet grinding of materials in the open or closed grinding process. The ball mill is mainly composed of a cylinder, a lining plate, a feeder, a mine discharging device, a main bearing, a transmission device and a lubrication system. Fig. 2A is a configuration diagram of a wet lattice type ball mill. Construction drawing of the mill. [next]
When the motor rotates the mill through the pinion gear and the large ring gear, the material enters the cylinder through the hollow journal through the feeder 1 . The material is ground in the body by the impact and grinding action of the grinding ball. The ground product is discharged through the hollow journal 8 through the bore of the drainage grid.
The inner wall of the cylinder and the end cover are provided with a lining plate. The role of the cylinder liner is two: one is to prevent the cylinder from being directly struck by the grinding medium and material and the corrosion and wear of the slurry; the second is to increase the grinding medium to produce grinding movement. Therefore, the material and geometry of the cylinder liner have a certain influence on the production of the mill. Lining betray many types of materials, generally can be divided into metal (alloy) and two categories of non-metallic materials. Lining a metal material are: high-manganese steel, high chromium white cast iron, hard nickel-manganese white cast iron and cast iron. Non-metallic material liners currently include: ceramics, rubber and rubber-magnetic liners.
The main advantage of rubber linings is their high corrosion resistance. The steel liner in the wet grinding production is easily corroded by the acid slurry, but the rubber liner has good corrosion resistance and corrosion resistance to acidic or alkaline medium, water, solution and the like at a certain temperature. The rubber has high elasticity and can be deformed by the impact of the grinding ball, and the force is small to reduce the wear; the energy saving effect is obvious. China's rubber linings generally save 10~15%; reduce the noise of the mill, generally reduce 10~15 decibels; light weight, usually 50~85% lighter than high-manganese steel; used for fine grinding operations, the service life is improved 2~ 3 times.
The geometry of the barrel liner is also varied and can be broadly classified into two types: smooth surface and non-smooth. Generally, the surface has a relatively smooth lining, and the relative sliding between the grinding ball and the lining plate is large. At the same rotation speed of the grinding machine, the grinding ball is lifted to a lower height, which is suitable for fine grinding; the surface shape is waved or The ribbed non-smooth lining has a large lifting height for the steel ball and is mostly used for rough grinding.
The thickness of the metal simple lining is usually 50 to 130 mm. The lining is generally fixed to the cylinder by screws. The difference between the overflow type ball mill and the lattice type ball mill is that there is no discharge grid plate installed at the end of the discharge, and the ore level difference is discharged.
In order to feed the crushed final product and the sand returning of the classifier into the ball mill, a feeder is installed at the ore end of the mill barrel. For dry grinding, the feeder can use a simple chute. In wet grinding, the commonly used ore feeders have three types: drum, snail and combined feeder.
The drum-shaped feeder (Fig. 3) is an open conical shell mounted on the hollow journal of the ball mill feeding end and rotating together with the mill; it is suitable for the material flowing into the mill at a position higher than the mill axis. occasion. The casing is welded from cast iron or steel plate with a spiral partition inside, and the partition has a fan-shaped hole for the material to enter the spiral portion of the casing. The material enters the conical shell through the feed hole and the scalloped hole, and the material is lifted by the spiral lifting plate inside the casing and fed into the hollow journal of the ball mill. [next]