high-pressure grinding rolls

The structure of the high-pressure roller mill is relatively complicated, the load is large, and there are many systems and components. In order to make better use of the device, it is necessary to understand its various components and nightly and necessary. The high-pressure roller mill is composed of a shafting system, a main frame, a feeding device, a transmission system, a hydraulic system, a lubrication system, a roller cover, and a detection system.

First, the spindle shaft system

The component consists of a grinding roller spindle with a certain thickness of wear-resistant material, a double row spherical roller bearing, a bearing seat, and inner and outer bearing end caps, a positioning ring, an end face thermal resistance, a water cooling system and the like.

The main shaft adopts split type and consists of two parts: the shaft body and the sleeve. The surface of the sleeve is welded with a wear layer. After the wear layer is worn, it can be repaired directly on the surface. If the sleeve is used, it cannot be repaired. To the extent that a new bushing can be replaced. The bearing support of the main shaft of the main shaft is a conical section, so that the disassembly of the main bearing can be carried out by means of an ultra-high pressure oil pump, which is convenient for inspection and replacement.

The main bearing of the high-pressure roller mill uses double row spherical roller bearings with self-aligning function. The bearing has the characteristics of large carrying capacity and long service life. It is concentrated with dry oil to ensure good lubrication.

The end face thermal resistance is used to detect the working temperature of the main bearing. It is closely attached to the outer ring of the main bearing to ensure continuous detection, alarm and control of the main bearing temperature. The water cooling system is used to reduce the operating temperature of the main shaft and the bearing, so that the shaft system can operate stably and continuously.

Second, the main frame

The main frame is the basis of the entire extrusion pulverization, and the crushing force is absorbed by it. In order to reduce the weight, all the welded structures are composed of upper and lower beams, left and right columns, bearing pins, positioning pins, guide rails and connecting bolts. See the main frame assembly schematic. The upper and lower beams and the left and right columns are integrally annealed after welding to eliminate the welding stress.

The upper and lower beams adopt the I-shaped structure and have greater rigidity and strength. The left and right columns and the structure of the I-shaped and box-shaped structures also have high rigidity, so that the entire frame can be connected into one. Rigid whole.

The load bearing pin mainly functions until the pulverizing force received on the column is transmitted to the upper and lower beams. Pay attention to the marking when installing.

The main role of the locating pin is to determine the center distance of the upper and lower beams on both sides.

The guide rails are provided as guides for the movable roller chocks. The rail widths on both sides are different, and the guide rails on the drive side should be wider.

Bolt sets are the key to ensuring the connection of the rack. Therefore, the high-strength bolts cannot be replaced by ordinary bolts, and the tightening torque should be controlled when tightening.

Third, the feeding device

The high-pressure roller mill feeding device is an important device to ensure that the material can enter the pressure zone uniformly and quantitatively, and the material is well squeezed. In operation, the material always fills the entire feed device and is directed into the pressure zone of the grinding roller. The feeding device is composed of a feeding port, a regulating inserting plate, a bracket, and a side plate pressing device. At the lower end of the side baffle, a hard alloy material of high hardness is provided in the portion of the pressure zone where the wear is severely punished. This reduces wear and improves the quality of the extruded material. The adjustment insert is used to control the thickness of the material cake to achieve the control of the treatment amount. It consists of a hand wheel, an adjusting screw and a card with welded material.

The side plate pressing device is used for controlling the gap between the side baffle and the end surface of the grinding roller. The device is composed of a bracket, a top screw, a butterfly spring and a spring seat.

The over-tightening screw can adjust the gap between the lower end of the side baffle and the end face of the grinding roller. Adjusting the pressure plate can adjust the top tension of the butterfly spring, so that the side baffle can ensure proper clearance with the end surface of the grinding roller during normal operation, and reduce the leakage of the end surface of the grinding roller.

Fourth, the main motor and transmission system

The main motor is the main power source for the entire high pressure roller mill. Two high-voltage three-phase asynchronous motors are used, which can be purchased by the user or commissioned by the manufacturer.

The transmission system adopts the internationally advanced planetary reducer suspension transmission. The output shaft of the planetary reducer is rigidly fixed to the grinding roller spindle by a shrink sleeve coupling. The gear unit is mounted on the basis of the grinding roller spindle and the gear unit can withstand the horizontal movement of the spindle. The output torque of the reducer is balanced by the torque support. The torque support includes a four-bar linkage and an elastic system. The torque support can satisfy the horizontal movement of the movable roller, and at the same time, it can play the role of load sharing, vibration absorption and buffering, and can reduce the processing and installation precision. All the hinge points in the four-bar linkage adopt the joint bearing with the sealing ring, which is highly adaptable. The elastic member in the elastic system employs a butterfly spring having a small axial dimension and a large coefficient of rigidity. In the working of the equipment, the top tension of the spring can be adjusted by adjusting the device to adapt the elastic system to the condition of the equipment load, and the universal joint drive shaft is used between the main motor and the planetary reducer. Since the universal joint drive shaft is disposed at the high speed end, the torque required to transmit itself is relatively small, and the rotational speed is high. And the cross-shaft universal joint drive shaft has the characteristics of high transmission efficiency, large transmission torque, balanced transmission, good lubrication conditions and large node inclination.

The shrink sleeve coupling used in the transmission system is a non-standard accessory, which consists of a conical sleeve, two shrink discs, a high-strength bolt set and a dust seal. The working principle is: tightening the high-strength bolt, so that the conical sleeve presses the hollow shaft of the reducer, and elastically deforms it, and is hung on the journal shaft of the grinding roller, and uses the friction generated by the positive pressure therebetween. It functions to transmit torque and reducer positioning.

Five, hydraulic system

The hydraulic system is designed to provide the required crushing force for the grinding rolls. Its main function is the hydraulic springs, which also have hydraulic protection. Its performance directly affects the quality of the crushed material and the safety of the equipment.

The system consists of three parts: pump station, valve table and cylinder (see hydraulic system diagram). The valve table, pump station and cylinder are mounted directly on the frame and are compact.

The pump station provides a hydraulic oil pump, which is mainly composed of an oil pump, an oil pump motor relief valve, a pressure gauge and an oil filter.

The oil filter of the pumping station is arranged in series with the pressurized main oil circuit, so that the hydraulic oil is filtered by the oil filter and then enters the main oil circuit to avoid blockage of system components caused by impurities entering the main oil circuit, and the system pressure can be based on The operation requires stepless adjustment. The pressure required to control the system can be adjusted steplessly. A pressure differential device is attached to the oil filter. When the filter cartridge is clogged and the pressure difference between the two sides reaches a certain value, an alarm signal is issued to clean or replace the filter cartridge by the operator. The valve table section is the main oil circuit and control oil circuit of the hydraulic system, and is composed of two capacity accumulators and an electromagnetic overflow valve. During operation, the four main cylinders are connected to the two accumulators through large diameter pipes so that the pressure between them is always the same and the dynamic characteristics of the cylinders are sensitive. The pilot-operated relief valve mainly protects the hydraulic system. It has the characteristics of dynamic response and large flow. Once the roller enters the foreign object and the system pressure increases, it can open the pressure relief in time to protect the host equipment. The relief valve can be hydraulically controlled and electronically controlled.

When commissioning and handling accidents, you can press the push button to relieve pressure or high speed pressure. A pressure sensor and an electric contact pressure gauge are additionally provided on the valve table. The hydraulic system pressure signal main control room and control cabinet can be interlocked with the main unit through the pressure sensor, which is also convenient for the operator to observe the operation. The electric contact pressure gauge is mainly used to control the upper and lower limits of the hydraulic system pressure. Control the opening and closing of the pump pump motor.

The four cylinders act directly on the movable roller bearing housing to provide the appropriate crushing force for the grinding roller. The cylinder force can be applied to the single-side bearing seat or the double-side bearing seat by the displacement of the oil circuit control system. When the grinding roller is moved, the horizontal displacement of the two bearing seats is detected and controlled by the displacement sensor. The cylinder consists of a cylinder, a piston, an end cap, a wear ring and a sealing ring. See the schematic diagram of the cylinder assembly. The cylinder is a double-acting cylinder, so that once the black system of the equipment fails. The movable roller can be pulled back in time with the cylinder to increase the nip and eliminate the malfunction. At the end face of the cylinder rod of the cylinder, a toroidal head is provided to prevent the radial load from being added to the cylinder when the axis of the moving roller is deflected.

Sixth, lubrication system

The lubrication system is used for the lubrication of the main bearing, the sealing and the lubrication of the movable roller bearing housing. The lubrication system can adapt to the dusty working environment and ensure the lubrication of the main bearing and the movable roller bearing housing under good lubrication conditions. It is mainly composed of a oil storage cylinder, a pump component with a flange connected, and a geared motor. Grease can be manually or electrically filled with a pump and added to the oil cylinder through a hose to prevent the grease from being exposed to dust and contaminating the grease. A pressure limiting valve and a fuse are provided in the lubrication pump to adjust the maximum pressure of the lubrication system. When the pressure in the system is exceeded for some reason, the rupture plate breaks and the grease overflows. A filter screen is provided on the lubrication pump to filter grease to prevent debris from entering the system and to ensure normal operation of the system. The grease from the lubrication pump is proportionally distributed to each lubrication point by the progressive distributor. There are two oil separators in the system, one on each side of the main frame.

This type of oil separator is a relatively advanced oil separator. It is characterized in that any one of the divided roads is blocked, and the whole system stops working. This avoids the Achilles heel that one or more lubrication points are broken and the operator cannot detect in time. A proximity switch is placed on the oil separator to signal the operator as soon as the oil separator stops working.

Seven, detection system

The detection system is distributed among the various systems as the detection control signals. The signals detected by the detection elements enable interlocking, indication and alarm between the systems. Realize automatic control of the device.

1. The nip detection between the two grinding rolls adopts two inductive displacement sensors, which are respectively arranged on the two bearing seats of the movable roller. Through the sensor, the nip of the two grinding rolls can be reflected at any time, that is, the material cake is reflected. thickness. When the two bearing seats move unevenly, the deviation can also be reflected. When one of the two bearing housings or the two-shaft bearing housing retreats to the set maximum displacement, an alarm is issued, and the main motor is locked in parallel to ensure the safety of the equipment.

2, the main bearing temperature detection end face platinum thermal resistance. Each bearing is tested separately. The end face thermal resistance is attached to the outer ring of the bearing to detect and reflect the working test of the main bearing at any time. When the operating temperature reaches the set maximum value, an alarm is issued to notify the operator.

3. Pressure sensor is used for pressure detection of hydraulic system. The sensor detects the signal and transmits it to the host control cabinet. When the system pressure exceeds the set maximum system pressure, an alarm is issued and the main drive motor is stopped.

4. Lubrication system work detection uses proximity switch. The proximity switch is installed on the system oil separator. When the oil separator is working normally, the proximity switch is instructed once every other time. When a certain oil circuit is blocked, the proximity switch does not operate at all times. However, it must be noted that the premise of the oil separator or the proximity switch must be based on the normal operation of the lubricating oil pump motor and the unbroken grease in the oil reservoir.

5, the pressure difference alarm of the oil filter, using the differential pressure device. When the oil filter is used for a period of time, the impurities under filtration may block the filter cartridge, causing the pressure difference between the oil passages on both sides of the oil filter to increase. When it is increased to a certain value, the sound and light alarm signal is emitted from the main control cabinet. It is worth noting that the signal is only sent when the oil filter is working.

Eight, roller cover

The main function of the roller cover: one is to prevent accidental casualties and equipment damage accidents; the other is to seal and reduce dust. Observation and repair door holes are provided on both roller covers to check the wear of the roller surface at any time while the equipment is running.