Troubleshooting of hammer crusherDate: 2019-08-02 Views:
Hammer crusher in the production process will appear various faults, only timely troubleshooting can ensure the production efficiency and profit.
1 hammer crusher hammer head failure
Hammer head wear failure mode is mainly impact gouging, accompanied by erosion microcutting wear.
1.1 fault characteristics
The macroscopic characteristics of hammerhead failure are wear and fracture.The wear of hammer head occurs on the surface and top of hammer head and the friction surface between hammer hole and hammer shaft.
1.2 fault analysis
The wear of hammerhead is normal, the fracture of hammerhead is abnormal.Its reason basically is the defect of material choice and manufacturing technology, make hammerhead itself strength and plasticity are insufficient, produce stress concentration, or use the factor such as improper to cause.
1.3 treatment strategy
1.3.1 choose the appropriate material to make the hammer head
According to the different size of hammer head and the different working conditions, choose the suitable material to manufacture the hammer head.For hammer heads under 12kg, materials with certain toughness and great hardness should be selected.For the 50kg class hammer head, it should choose high toughness super high manganese steel manufacturing hammer head, its yield strength should reach 450N/mm2, the initial hardness should reach HB260~300;For large crusher 90kg and 125kg hammer head, must choose high toughness materials, supplemented by other comprehensive properties.
1.3.2 existing life-extending methods for hammers
To improve the wear resistance of the hammerhead, a thin layer of cemented carbide is welded on the hammerhead working surface.
The manganese steel system after the hammerhead wear, can use manganese steel electrode surfacing.In the process of surfacing of hammer head top, the composition of 1.2~1.5mm unequal shaft grate granular cemented carbide can be introduced into the surfacing metal, while the basic alloy is special high chromium cast iron.When lilitte is added, it is filled along the top of the hammer head to obtain more hard granulates.It can also use surfacing paste (surfacing paste is a new wear-resistant material made by powder of ferrochrome, carbon and iron relying on plastic binder).Namely on surface coated surfacing layer thickness for 5 mm surfacing cream, after 5 ~ 12 h dry, ф 10 mm copper coated carbon electrode to melt, hammer head to the anode, dc is connection with surfacing, current is 400 ~ 450 a, surfacing layer thickness is 2.5 ~ 3.5 mm.
2 hammer crusher grate broken off
2.1 fault characteristics
The grate groove of the grate support is worn out, and the end of the grate collapse, leading to the grate fall off or break off the grate itself, jam bucket elevator and other post-sequence equipment, and even the attached motor is burned.
2.2 fault analysis
Grate is cast with high manganese steel, or some forged steel, long-term bearing hammer head and material impact, or because of accidents caused by the grate fracture, loose, bending, until down.The grate groove of the grate supporting frame is also easy to be worn out, resulting in micro-cracks and even collapse of the groove end, leading to the grate drop.In addition, the insufficient thickness of the grate surface, the unreasonable structure of the grate itself, the unreasonable gap between the hammer head and the grate, and the improper area of the lining plate in the rack, which hinder the adjustment of the grate, as well as the lax assembly and unreasonable design of the grate screen, are also reasons for the grate drop.
2.3 treatment countermeasures
2.3.1 select appropriate materials to make grate and grate support.
The grate not only plays the role of partially crushing materials, but also plays the role of controlling the particle size of finished products.Therefore, generally choose high toughness, hardness (slightly less than the hammer head) of the material made of grate and its support.Usually cast in high manganese steel, but also can be forged.According to the introduction, forging grate can increase its wear resistance and toughness.
2.3.2 timely maintenance and improvement of assembly quality.
The gaps between gratings should be suitable and arranged in a compact manner. Some gratings with large deviation should be repaired as necessary to remove burrs or other parts that may hinder assembly.When the grate spacing is larger than the granular-size index, it should be replaced or repaired in time.When the grate falls or looses, it should be solved by strict assembly.After assembly, it should be pressed tightly without loosening.In order to increase the strength and avoid bending deformation, a convex boss can be added in the middle of making grate with small section and large length.
2.3.3 improve the grate structure through technical modification.
With a wear-resisting electrode in the grate on the surface of the surfacing welding layer of 20~30mm, to increase the thickness of the grate.
(2) each grate with stainless steel welding rod in the grate frame, constitute an integral, improve its stability.
We can increase an arc length on the end of grate frame to enlarge the work area of hammer head.
In addition, cut a part of the original lining board, to appropriately reduce the width of the lining board, convenient adjustment of grate rack.
It has changed the original designed grate provisions with groove into without groove grate, the short grate into the long grate with convex edge in the middle.
3 single section hammer crusher rotor bearing high temperature
The bearing temperature of single section hammer crusher is normal as long as it does not exceed 70~80℃.But the temperature of rotor bearing is often on the high side.
3.1 failure performance
The temperature of rotor bearing can reach more than 80℃ after starting the machine for 3h. Frequent alarms are given. It is useless to blow one bearing with two fans, so it is forced to stop and cool down.
3.2 fault analysis
The causes of excessive temperature of rotor bearing may include the following aspects:
The bearing clearance is too small, resulting in excessive bearing temperature rise.
The oil brand choice is improper, viscosity is too big or too small viscosity is not easy to form oil film, can lead to high temperature rise of the bearing.Especially when the viscosity of lubricating oil is high, it not only increases the internal friction between lubricating oil molecules, but also increases the friction between oil products and metals, thus generating too much heat.
The installation is not correct, rubber plate coupling rubber plate is too thick, too much stiffness, insufficient deflection, resulting in bearing rivalry, friction intensification, heat generation too much.
In addition, the amount of oil is excessive, up to or beyond the center of the most below a ball or roller, not in line with the use of oil bath lubrication of rolling bearings, heat generation in constant agitation is too much.5] shell heat dissipation area is insufficient, heat cannot be sent out in time, cannot balance in the required temperature, so the temperature of rotor bearing is high.
3.3.1 adjust the bearing clearance to meet the specified requirements.
3.3.2 rainfall distribution on 10-12 alignment motor and the alignment of the crusher rotor, and the level of two bearing in motor shaft neck, crusher rotor and flywheel on the bearing outer race to find the level of the motor rotor and rotor respectively, and then use pipe review, review of the motor and using the method of thread hanging a heavy hammer crusher centerline of straightness, until meet the requirements.
3.3.3 reduce the stiffness in the connection between the rotor and the motor of the crusher, that is, remove the rubber plate of the rubber plate coupling, so that the deformation in operation can be timely absorbed by the rubber plate, reduce the rotor shaft (crusher) in the bearing, and then reduce the additional force and friction in the bearing.
3.3.4 proper selection of lubricating oil and reasonable determination of oil loading.It is reported that the use of viscosity small N68 extreme pressure gear oil instead of the original N150 load extreme pressure gear oil, and the amount of oil control (oil standard oil surface) in the bottom of a roller center line below, that is, the height of oil control in 105mm after the re-start, bearing temperature to maintain 70℃ below.