Feed Equipment Knowleagde

Reasonable use of the hammer and sieve of the pulverizer to extend its service life is of great significance for reducing costs.

The use and replacement of the hammer
1. After using the hammer-type feed mill for a period of time, it will be found that the hammer wear on the same mill is different. For the radial feed mill, due to the blower effect generated when the mill rotor is running, The material layer is thicker on both sides in the width direction of the pulverizer, so the hammer pieces on both sides wear faster, and the wear amount is 2 to 3 times that of the intermediate hammer piece, and the axial feeding pulverizer faces the feeding direction. The first row of hammers wears the fastest.
2. Replacement of the hammer
(1) A hammer can be used four times repeatedly. The first corner can be replaced with the other three corners. For the pulverizer that can be reversed, if the motor is reversely operated, it will be replaced. Two corners are used.
(2) When replacing the hammer with the dismounting pin, it must be in accordance with the original hammer arrangement order, and it can not be disturbed, otherwise it will affect the balance of the rotor and reduce the crushing ability.
(3) When the hammer is worn, it should be replaced by the whole pair. Otherwise, the crusher will generate vibration and noise and reduce the service life of the bearing.
(4) Hammers that meet the heat treatment requirements should be selected. Some hammers are as hard as inside and outside, which can cause the pin to wear in advance.
(5) When replacing the whole hammer, the pin should be replaced at the same time. The pin is generally treated with 45# steel and the hardness is HCR28-32. It is not allowed to use poor materials instead of premature wear or accident after grinding.
3. Hammer repair
The wear of the tungsten carbide alloy surfacing hammer is beneficial to increase the hammering ability and increase the life of the screen. If tungsten carbide alloy surfacing hammer is used, its life is about 6 times higher than that of ordinary hammer, and the cost is only increased by more than 2 times. Generally, the hammer is worn into a kitchen knife shape. When the pulverizer is working, the hammer piece generates a large striking force and compressive stress on the sieve through the material, thereby increasing the wear of the sieve. According to the test results, after the tungsten carbide alloy is used to weld the hammer, not only the life of the hammer is improved, but also the sieve can increase the life by 32%, the productivity can be increased by 8.32% compared with the ordinary hammer, and the power consumption is reduced by 7.15%.
With this hammer piece, the surfacing process is slightly complicated. During the operation, the tube is filled with granular cast tungsten carbide electrode, and the oxyacetylene flame is deposited on the hammer base metal. The tungsten carbide particles themselves are not melted during the welding, but by means of After the base metal is melted and bonded together, the surfacing temperature is generally lower than its melting temperature (2525 ° C, 2850 ° C), and the cast tungsten carbide does not undergo a structural transformation, so it can maintain its original high hardness (HCR93 -93.7) and high wear resistance. During the surfacing, a reducing flame should be used to use an excess of acetylene to ensure that the surfacing surface and the surfacing alloy are not oxidized. In order to avoid particle oxidation during the surfacing process, a distance of 3 to 4 mm should be maintained between the flame core and the surface to be welded, and the center of the welding torch should be 16 ~25 with the surface to be welded. inclination. The amount of weld overlay should be controlled so that the weight difference between the pieces of the hammer after the surfacing is not too large, so as not to affect the balance of the rotor.