Working principle of ring roller grinding and several problems that should be paid attention to when processing fine powder

Ring roller grinding works :

The ring roller mill uses the principle of impact, extrusion and grinding to pulverize the material. There is a large active gap between the grinding ring and the pin shaft mounted on the grinding ring bracket. When the grinding ring bracket revolves with the main shaft, the grinding ring is urged by the centrifugal force to the grinding ring, and the inner wall of the grinding ring is pressed and rotated around the pin shaft. When the material passes through the gap between the grinding ring and the grinding ring, it is impacted and squeezed by the grinding ring. Press, grind and smash. The pulverized material falls under the action of gravity, falls to the hopper tray and is smashed into the airflow into the grading chamber for grading. The qualified fine powder is collected by the grading wheel into the rear collecting system, and the coarse material is circumvented into the shunt ring and re-entered. The pulverization chamber is pulverized. The grinding ring is a single layer or a double layer of upper and lower layers. When the double-layer grinding ring pulverizer is working, the material is pulverized again when passing through the gap between the second layer grinding ring and the grinding ring. Therefore, the material is pulverized sufficiently and the product fineness is qualified.
Several problems should be noted when ring roll grinding of fine powder:

1 The contact between the grinding ring and the grinding ring is non-rigid contact, wherein the gap pad has a layer of pulverized material, the gap between the grinding ring and the pin shaft is large, and it has a certain retreat, and the current reflected to the spindle motor is not added. When it is debugged, under the premise of ensuring the fineness of the product, it should be gradually increased; if the feeding is too fast, the material will be unbalanced in and out, and the discharge speed will decrease, and the coarse powder will be taken out, and the product granularity will be uneven.

2 After stopping the feeding, there are still materials in the pulverizing chamber. All the materials must be pulverized and discharged before stopping, so that the next startup is smooth. After the feed is stopped, it should be kept on for about 5 minutes. When a sudden power failure occurs, the motor coupling is hand-held before the power is turned on, and the rotation is flexible and the power is transmitted. If the card is severely stuck, the material should be turned on.
Advantages of HLM ring roll grinding in heavy calcium crushing
Ring roll grinding is ideal for dry production of ultra-fine calcium powder. As an important inorganic filler, calcium carbonate is one of the three major fillers in the production of chemical products, and it is widely used. With the rapid development of China's economy, the requirements for the grade and fineness of calcium carbonate are getting higher and higher. In the past few years, domestic heavy calcium processing was mainly based on Raymond mill. The fineness of processed products is relatively coarse, generally in the range of 200-400 mesh. In recent years, although the technical modification of Raymond mill has been carried out, the product fineness has been improved. 600~800 mesh, but still can not meet the user's requirements, the added value of the product is low, and the resources cannot be used more effectively. The new ring roll mill can produce D97<10μm fine powder at a time when the crushing material has a particle size of not more than 20mm, water content of not more than 8% , Mohs hardness of 6 or less, and has many advantages. .
1. Investment and high efficiency:
Compared with large-scale complete sets of equipment, the investment saves nearly half/production of ultra-fine heavy calcium fine powder. At present, there is a ball-grinding and grading production process in China, and the product fineness can reach D97<10μm . The construction of a micro-powder production line with an annual output of 10,000 tons requires an investment of 1.39 million yuan. One piece of HLM-880 ring roller mill is used to produce the same fineness of the product, with an annual output of 10,000 tons. The investment is only 500,000 yuan, saving 60% of investment .
2. High classification accuracy:
With the internal grading device, the grading wheel has a unique structure, good grading effect and no large particle pollution. A mining company in Guangdong uses the same calcium carbonate ore, one is made from a vertical grinding line made in Taiwan, and the other is made by HLM-780 ring roll milling. It is also tested with a Malvern particle size analyzer made in the UK. The fineness of the product can reach the expected product fineness (about D97=12μm ).
3. Low energy consumption :
The product has a fineness of D97<10μm and a power consumption of 95kW·h/t . Compared with other models, it has obvious power saving and is a new type of energy-saving product.
4. Work is stable and reliable:
The drive spindle of the HLM series ring roller mill is driven by a reducer, which has low energy consumption, high efficiency and efficiency >9 6 % . Through the industrial test of the first-stage belt reduction drive and reducer drive, the following conclusions are drawn: the first-stage belt drive has simple structure and low cost, and the transmission efficiency is 90~95% . When overload occurs, it will cause slippage, and the belt movement is not. The steady state directly affects the normal work of pulverization. The pulverized powder has more coarse particles, which causes the grading load to increase, and the classification motor is easy to burn.
In order to reduce the sliding loss and reduce the transmission ratio, only the pulverizing rotor speed can be increased, and as a result, the host vibration is large and the noise is large. Switching to the traditional Raymond mill transmission structure, the power utilization rate is improved, and the above shortcomings are overcome. Although the manufacturing cost is slightly increased, the equipment operates reliably and the product quality is stable.
5, higher specific surface area:
The specific surface area of ​​the powder is the surface area occupied by the unit mass, in m 3 /g , which is an important indicator of the ability to participate in chemical reactions. The contact surface is large, the synthesis process is more perfect, easier to control, the utilization rate of calcium carbonate is higher, and the powder consumption rate is lower, thereby indicating high activity. Therefore, the specific surface area has become an important indicator of the activity of ultrafine calcium carbonate powder. HLM ring roll mill can produce ultrafine powder with specific surface area of 2.24m 3 /g (D97=10 μ m)~3.04m 3 /g (D97=4μm) , which is much higher than other domestic equipment.

Oil Pan Gasket function is to seals the oil pan to the bottom of the engine.
Oil Pan gasket Material: Cork, Framework Rubber, Metal Rubber. Sealing Paper,

1 CORK: Cork material is the earliest used in the oil pan seal. The most widely applied, Is a highly applicable sealing material. It is feather is: simple process, raw material is simple and easy. Low cost. 
But a wide range of apply does not mean it`s fully suited to the oil pan seal.
Its disadvantage is also very obvious: Easy to leak; Easy to pressure explosion when install the screws. 

European and American manufacturers have no longer use this material many years ago, but the aftermarket still have a huge inventory fort this cork oil pan gasket. 

2 RUBBER: Rubber oil pan gasket is widely used in the foreign maintenance market, It`s a very nice sealing material, The specific material can be: NBR, ACM,FKM. European cars prefer to use rubber oil pan gasket, such as Mercedes-Benz, Audi, and Volkswagen and so on.

3 Sealing Paper: Sealing paper oil pan gasket is a new material, it`s performance stable, good sealing effect, Suitable for flat sealing. The US repair kits form TTK,ATC,TRANSTEC etc- are mostly use this sealing paper material.  

4 Metal Rubber: Also named as module rubber, hard rubber, its use metal as a skeleton and coated with rubber outside, representative one like 4T65E, This is a new trend of the oil pan gasket, It combines the advantages of rubber material and avoid the disadvantage of not easy to fix. At present United States almost all new transmission box is use this metal rubber sealing gaskets. This is also widely used in the engines.


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