The reason why the crusher board hammer does not wear well
Date：2019-07-31 15:53 Source：未知Views:
Crusher board hammer damage mode is mainly two kinds: loose and broken.No matter what kind of damage caused by the impact is very large, light to break other accessories, damage to the rotor and counter frame.Heavy damage to the rotor center bearing, and even personal safety problems, the cost is very large.
Factors affecting the service life of board hammer
The plate hammer of the impact crusher turns with the high speed of the rotor, hitting the broken material, and the material impact and wear off, so it is extremely easy to wear.The factors that affect the service life of the board hammer are: the material of the board hammer, the quality of manufacture, the property of the broken material, the circumferential speed of the rotor, the structure of the board hammer, the handling capacity and so on.
(1). Material of board hammer
Half of the counter plate breaking hammer in the market is made of high manganese steel, high chromium cast iron and other wear-resistant materials.An ordinary impact crusher, if used for crushing limestone, works 24 hours a day, and the high chromium cast iron crusher board hammer USES an average of 300-700 hours.But if used for crushing granite, the service life will be shorter.
In the domestic market, high chromium cast iron is the most common hammer material.Therefore, it is now common to turn the counterattack board hammer directly into a high chromium board hammer.And high manganese steel is most often used to break back lining plate.The materials of the products produced by different manufacturers are basically the same, but the quality of the products also depends on the specific composition, casting process, production equipment and production experience of high manganese steel.In addition, the mine also needs to choose the most suitable products according to the actual situation on the mine.
(2) circumferential speed of rotor
In addition to the board hammer material impact on its life, the following reasons also affect the life of some crushers board hammer: because of the impact crusher rotor linear speed is higher, the rotor with 3-6 pieces, up to 8-10 pieces of board hammer.
The time interval between the front and rear hammers is only a few tenths of a second.In such a short time, only a few materials can enter the strike area, and most materials, especially large materials, only one end into the strike area, so the board hammer is not hit on the center of gravity of the material block, that is, the board hammer and the whole material block front impact broken, but on the oblique collision.
In this way, not only reduces the crushing effect, but also causes the sliding friction between the material and the hammer, which causes the hammer to wear very quickly.In addition, the counterattack plate with powder material, the board hammer and powder friction is more serious, the board hammer more rapid wear.
In order to reduce the wear of the plate hammer, the number of the plate hammer on the rotor should not be too much, the diameter of the rotor should not be too small, to increase the height of the hammer, and try to give people the powder material, soil and moisture in advance screen.
(3) structure and fixing method of plate hammer
The structure of the plate hammer and its fixing method also have an effect on its life.At present, our country manufactures the impact crusher, the plate hammer mostly USES the countersunk screw fixation.This fixing method is simple in structure, convenient in disassembly and replacement without lifting the rotor out of the body.Overcome this shortcoming, the board hammer is fixed more firmly, but need to work on the back groove of the board hammer.Some crusher hammers are inserted into rotor grooves from the side.Each side has 1:5 slope, by the centrifugal force produced in the operation of the wrench.The two ends of the board hammer of this kind of structure should be pressed with a pressing board to prevent movement.This fixing method is not very reliable, it is not safe to work, the board hammer is easy to fly out, it is best not to use.
Another USES wedge iron to fix the board hammer. The board hammer is put into the rotor groove. From the rotor side, wedge iron with slope on both sides is driven into wedge hammer.Plate hammer pre - tightening, work under the role of centrifugal force, the plate hammer, wedge iron and rotor will be more and more tight, reliable work, but difficult to disassemble, rarely used at present.