Clearance problem leads to heat treatment of crusher bearing

Product introduction:https://www.lvssn.com/crusher/

The bearing of limestone crusher has the problem of long-term heating, and two sets of bearings need to be changed every year, which not only affects the increase of expenditure, but also affects the production efficiency. The clearance problem leads to the treatment measures of heating of the bearing of crusher
 

1. Basic information of crusher

In the production process, the temperature of the two sets of bearing of the crusher rotor is around 85℃ all year round. Especially in summer, the bearing must be cooled down with compressed air, or even cooled by cooling water on the bearing seat at the end of the pulley, so as to maintain normal production.Crusher free end (non-transmission end) bearing due to heat damage, every year to replace two sets.

 

2. Analysis of bearing heating

 

(1) selection of lubricating oil:

The rotor bearing of the crusher is lubricated by mobil EP2 grease. The various indexes of grease can meet the stable operation of the bearing.
 

(2) problems of lubricating oil pollution:

Open the end cover of the bearing and check, the grease is clean and no impurities such as ash are introduced, so as to eliminate the bearing heat caused by this problem.
 

(3) excessive addition of grease in the bearing:

In general, excessive grease will lead to poor bearing heat dissipation, resulting in bearing heat.There is an oil drain hole at the lower end of the end cover of each bearing seat of the crusher rotor. Excessive oil addition will lead to a rise in temperature in a short time. After the old oil is discharged after a period of operation, the temperature of the bearing will return to normal.The crusher bearing perennial temperature in 85℃ or so high temperature operation, it should not be caused by this.
 

(4) bearing assembly:

Open the outer end cover of the free end bearing for inspection, measure the distance from the outer ring of the bearing to the side of the bearing seat is 26.3mm, and measure the length of the end cover stop of the bearing 30mm.
 

(5) calculation of thermal expansion of rotor shaft:

The center distance between the two ends of the bearing is 3400mm, the working temperature difference is 100℃, the expansion coefficient of ordinary carbon steel is 1.2×10-5/℃;The expansion amount was 4.08mm(3400mm×100℃×1.2×10-5/℃).
 

Compared with the two data, the problem of bearing heating was confirmed. It was because the outer end cover of the free end bearing was pressed too tightly, the end cover stop was pressed on the outer ring of the bearing, and there was no thermal expansion of the rotor shaft, which caused the bearing heating of the crusher.

When the limestone crusher works normally, the thermal expansion of the rotor shaft is 4.08mm.When the rotor is running, the bearing temperature will gradually rise, the rotor shaft will also elongate, and the free end bearing will produce axial displacement with the change of temperature.In consideration of assembly size and other errors, during the installation process of the rotor, a distance of more than 10mm should be reserved between the outer end cap and the outer ring of the free end bearing to ensure the thermal expansion of the rotor shaft in the normal production process. Otherwise, the bearing will suffer from high temperature due to the axial force and run for a long time, and the bearing will be damaged.

Therefore, the problem of swimming clearance is the root cause of bearing running at high temperature for a long time.

 

3. Measures to solve the heat of crusher bearing

According to the above analysis, the non-axial thermal expansion of free-end bearing is the main cause of bearing heating, which can be solved by adjusting the gap between the outer ring of bearing and the stop of bearing end cap.
 

There are two solutions, one is the bearing end cover stop car off 10mm;The other is to add a gasket to move the bearing end cover out.

After proper installation of the limestone crusher, the working temperature of the free end bearing is stable at 56℃ and the temperature of the belt wheel end bearing is stable at 68℃ after starting production, and the bearing heating problem is completely solved.The abnormal situation of the equipment is mostly caused by the incorrect installation according to the technical specification.As long as the cause is found and targeted technical measures are taken, the problem will be readily solved.

The page source:https://www.lvssn.com/Industry/Clearance-problem-leads-to-heat-treatment-of-crusher-bearing.html

Choose to buy the main points of crusher equipment

Product introduction:https://www.lvssn.com/crusher/Cone-crusher.html

With the rapid development of industrial construction, the types and types of crushing equipment are also increasing.The increasing types and models of crushing equipment provide more choices for users, and at the same time, customers are faced with the situation that they do not know how to choose appropriate crushing equipment when selecting crushing equipment.Choose to buy the main points of crusher equipment

For an aggregate sand and stone plant, different capacity and function of the crushing equipment to configure the production line to meet production requirements.So how to choose to adapt to their own stone field production requirements of the crusher equipment?

 

1. Characteristics of stone

The hardness, mud content and water content of the stone are very important data. In addition, the head breaking equipment should be selected according to the maximum particle size of the stone.

If the hardness of broken stone is too large, such as granite, basalt, pebbles and other stone, can choose jaw crusher, cone crusher for crushing;Less rigid stones, such as limestone, can choose the impact crusher for secondary crushing.

To minimize the wear of the tooth plate and other wearing parts, that is to save the production cost, but also improve the production efficiency.

 

2. Requirements on product quality

The customer's requirements on the size of the finished product, stone shape and other requirements also determine what kind of crushing equipment should be chosen.If the size of the crushed sand is different, the screening equipment should be equipped for screening.

In many projects, sand if the soil content is too high, also need sand washing machine, add a sand washing process.

 

3. Use of finished products

Need to according to the user finished stone configuration of stone production equipment reasonable arrangement.For example, highway, high-speed railway, dyke and other projects have high requirements on stone materials. If such projects are constructed with cracks and sharp corners, the risk of project collapse will be increased.The impact crusher is usually used to treat the stone material to meet the standard of fine material.

When choosing crushing equipment, users should take the above three points into full consideration and choose crushers according to their actual needs. If you need, you can leave a message with us, and we can give you more choices.

The page source:https://www.lvssn.com/Product/Choose-to-buy-the-main-points-of-crusher-equipment.html

Several key components of vertical mill

Product introduction:https://www.cementepc.net/grinding/LVRM-Vertical-Mill.html

Vertical mill is an ideal large-scale pulverizing equipment, widely used in cement, electric power, metallurgy, chemical industry, non-metallic ore and other industries.It sets crushing, drying, grinding, grading conveying in one, high production efficiency, can be block, particle and powder raw materials into the required powder material.You know, the key components of the vertical mill.

Vertical mill has high efficiency in production, energy conservation, environmental protection, material drying ability strong, stable product quality inspection, wear small, high efficiency, etc. But in the actual production typically has the production and safety issues such as excessive vibration, let's learn about the simple vertical mill's several big functions and maintenance of key parts, in order to better to protect the security of vertical mill production.
 

1, the roller

For the vertical mill, the roller is the heart of the vertical mill. The roller of the vertical mill is inclined in design, which has two main functions: one is to increase the contact area and improve the grinding efficiency;The second is to prevent large pieces of material from falling off the edge, blocking the air inlet.In addition, with the increase of the grinding time, the grinding roller is gradually worn, which can be used to turn the surface of the grinding roller, extending the service life and saving the cost.

Vertical mill and vibration due to long-term wear, each connection gap get bigger, easy to cause the center of the roller location deviation, can form to pull rod and twisted, on the pull rod torque, intensifying mill vibration, destructive damage to the hydraulic cylinder and the chassis base, and pull rod and pull rod bolt fracture easily.In daily maintenance, we should arrange at least one to two times of planned maintenance according to the production status every year, mainly to test the radial system of the mill and replace worn and aged spare parts.
 

2. Hydraulic tension system

The hydraulic tension system is one of the most important equipment systems in the vertical mill. It plays a key role in the stable operation of the vertical mill and is also a link prone to failure. The huge grinding pressure exerted by the roller on the material is provided by the hydraulic system.
 

Generally, the reasons for the failure of the hydraulic system mainly include the damaged fault of the accumulator nitrogen air bag and the frequent start-up fault of the high-pressure oil pump in the hydraulic station. In order to ensure the normal operation of the hydraulic system, the following points should be achieved in production:

(1) the hydraulic fluid in the hydraulic system is required to have a higher degree of cleanliness.In case of small particles into the hydraulic oil, resulting in cylinder scratches, nitrogen balloon damage;

(2) during the use of the hydraulic oil, the oil quality should be tested and checked regularly every half a year, and the hydraulic oil should be replaced in time if the oil is emulsified;

(3) a reasonable grinding pressure should be set according to the characteristics of the material. In normal production, the actual operating pressure should be set between 70% and 90% of the maximum pressure limit.
 

3. Other key components

In addition to grinding roller and hydraulic tension system, the safe and efficient production of vertical mill also depends on the following key components!

(1) the powder separator can timely select the particles of a certain size in the grinding materials, avoid the occurrence of material aggregation, adhesion to the grinding body and bin, and reduce the over-grinding of the grinding materials;Improve grinding efficiency.Generally, cone concentrator is mainly used for coarse powder selection (conventional powder selection);The movement direction of the impeller of the cage separator is opposite to the direction of the blade tilt, which increases the difficulty of powder selection and improves the accuracy of powder selection. It is mainly used for fine powder selection.

(2) reducer is the heart of the safe operation of the vertical mill. No matter the vertical mill reducer supplied by domestic and foreign manufacturers, it is necessary to detect the meshing of the spiral bevel gear pair by coloring before installation and operation.It is necessary to stop the machine after half a year's operation.In order to ensure the safe operation of the reducer, it is necessary to know the running condition of the gear and bearing of the reducer by checking the oil filter net impurity regularly and cooperating with the endoscopic examination.

(3) the functions of the hot blast furnace are mainly as follows: 1. Reduce the oxygen content of the air in the mill system to prevent explosion; 2.2. Drying materials;3. Pressurize to handle materials with certain humidity.

(4) explosion-proof valve (plastic sheet) is located on the top of the separator. When the pressure in the grinder is too high, the plastic sheet will explode automatically, thus preventing the explosion of inflammable and explosive materials when grinding.

(5) the limiter is a device used for fine-tuning the distance between the grinding roller and the grinding disc, so that there is no contact between the two, to avoid damage caused by contact between the grinding roller and the grinding disc due to uneven cloth vibration during work.

The page source:https://www.cementepc.net/productknowledge/Several-key-components-of-vertical-mill.html