The Composition Of The Complete Plant Of Ring Roller Mill


The complete plant of ring roller mill is made up of four systems which are the Main engine, powder extraction system, feeding system, and control system (Fig.1). According to the needs of different industries, the material used for making some accessory may choose carbon steel or stainless steel or other material of different quality.


Fig.1 The sketch map of the complete plant of HLM series ring roller mill

1. Material storehouse 2. Electric vibrating feed 3. Main engine  4. Grading system

5. Bag-type deduster 6. Air valve  7. Fan 8. Discharge stirrer 9. Closing fan motor

10. Electrical control cabinet(large machine is not including independment cyclone)

2.1 The configuration of the main engine and the operating principle of the hoop-roller mill

The main engine of ring roller mill mainly includes the crushing system, grading system, power and speed reducer system.

Figure two is the sketch map about the Operating Principle of hoop-roller mill. There is a big space for moving between the grinding hoop and the pin axletree which are installed on the grinding hoop bracket. When the grinding hoop bracket revolves following the principal axletree, the grinding hoop will be thrown towards the grinding circle with centrifugal force and impact the grinding hoop wall. So the grinding hoop can also rotate around the pin axletree. When the material passes the clearance between the grinding hoop and the grinding circle, it will be crushed because of the impact, rolling and grinding by the grinding hoop. The crushed material falls on the material throwing dish with the gravity, and it is thrown to the airflow passage. At the effect of the negative pressure attraction of the systemic fan, the crushed material enters the grading cell following the airflow to be graded. The eligible fine-powder passes the grading wheel, and then goes into BEOL collection system to be collected. Meanwhile, the rough material is thrown onto the wall of the diffluence hoop, and drops into the smashing cell to be crushed over again. The grinding hoop is two-double distributed. When the material passes the clearance between the grinding hoop and the grinding circle of the first floor, it is crushed for the first time. And when it passes the second floor, it is crushed again. So the material is crushed sufficiently. And then the product is fine.


Fig.2 The sketch map about the operating principle of HLM-580 centrifugal ring roller mill

1. Grinding wheel 2.Diffluence hoop 3.Grinding circle 4.Pin axletree

5. Grinding hoop 6.Grinding hoop bracket 7.Material throwing disk 8.Stator frame

2.2 The extraction system of the powder 

The extraction system of the powder consists of the high pressure centrifugal fan, Pulse filter, transporting pipe, closing fan motor and other main components. The eligible crushed powder is extracted from the main engine by the negative pressure which is generated by the high pressure centrifugal fan. After the gas-solid separation by the vortex segregator of the first stage and the air cleaning by the bag-type deduster of the second stage, the depurative air is discharged from the fan outlet. And the collected powder is further mixed by feed screw ,finally discharged from the closing fan motor output.

2.2.1 Bag-type deduster

Bag-type deduster filters the dust-laden gas using the porous fibre filter bags. It can separate the dust which is below 5μm, making the exhaust gas reach the national discharge standard. The HLM series Hoop-Roller Mill uses the pulse blowing-back bag-type deduster. It mainly consists of the cabinet (also called bag house), filter bags, frame and deashing device. Except that the customer requires the material of especial quality, the filter bags usually use the water-repellent and oil-proof punched felt.

The dust-cleaning device of the pulse bag-type deduster consists of the pulse valve, spray-tube, air storage,bag, induction unit (This equipment uses Venturi tube) and control instrument. The compressed air which is the power of the dust-cleaning is supplied by the customers yourselves (For details, see 4.4). All the other devices are supplied by our company in whole set.

2.2.2 Closing fan motor(also called air-lock material-unloading device

The hoop-Roller Mil uses the convolution-type Closing fan motor which is installed under the vortex separation or the dust catcher ash bucket. It can both discharge the collected powder and prevent from the air outside entering which may affect the separation effect. It mainly consists of the convoluted impeller, crust, cycloid pin gear speed reducer, electrical machine and other parts.

2.2.3 High pressure centrifugal fan

    It uses the negative pressure produced by the fan to extract and transport the powder.

2.3 Material feeding system

According to the characteristic of the material, feeding has two types that are screw-feeding and electromagnetic vibrating-feeding. The customers can select any one of them. Screw feed uses frequency conversion to control the feeding quantity. And the electromagnetic vibrating feeder uses the electric vibrating controller to control the feeding quantity. Usually, the screw feed is for the fine powder, and the electromagnetic vibrating feeder is for the material of rough grains.

Material feeding system consists of the central material storehouse, central storehouse bracket, screw feed (or electromagnetic vibrating feeder), control device and other parts. In the running process, the change of the feeding quantity and the running status of the complete set of the equipment interact each other. That makes the output and the product fineness keep in good condition.

2.4 Control system

The control of the Hoop-Roller Mill has two types. That are the hand control and auto control by programmable logic controller(PLC). It usually uses the hand control. The control principle is showed in figure three (see addenda):

 Pulse control instrument is solely installed near the dust catcher. Except that, all the control circuitry and the instruments are installed inside the control cabinet. So the manipulation is convenient.

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