1. Reason analysis
The wear between rotor and hammer caused by material friction and impacting force is uneven during long time running, which causes a clearance between the interface of rotor and hammer，and there is a big difference with its rotation center due to rotor gravity, thus resulting in additional force, generate vibration and wear bearing . As a consequence, it will bend the shaft and cause serious wear and tear, the installation of the plate hammer will be badly affected, the shear bond strength of plate hammer can shorten the service life of the plate hammer, bend or break the crew of plate hammer. All these affect the normal operation badly.
2. Solution method
1. Keep the balance of the rotor when repair motor and plate hammer. Preparations are as follows:
1) Lift crusher head cover, remove V-belt, clean bearing and bearing housing on both sides;
2) Fill lubrication oil after cleaning, rotate the rotor by hand till motor is flexible;
3) Observe motor's balance when it rotates;
4) According to imbalance situation of the rotor rotation, make a mark on welding repair position.
5) Divide the length of the rotor into several segments, make marks on each 200 mm segment length;
6) Replace the old plate hammer with new weighed ones, make marks with chalk on the plate hammer;
7) Prepare hand grinding machine and arc-welding set.
2. The operation steps of repair the rotor and configure the flat hammer:
(1) On the first section of cylinder of equaled rotor, welding the wear parts with manual arc;
(2) After welding to the original design size of rotor, stop welding and smooth the surface that contact with side of the flat hammer with the hand emery wheel;
(3) Should observe the balance condition of rotor according to the static balance experiment method. If there is imbalance, continue to surface welding counterweight in the original overlaying position with manual arc until the rotor balance;
(4) Other segments of rotor welded with reference to the above steps;
(5) The same or slightly different weight of flat hammer should be installed with symmetric configuration along with around the repaired rotor, which makes the rotor have a better balance.
3.Operation and maintenance points:
1) Should often check the flat hammer (blow plate), impact plate and guard plate, as well as the abrasion condition of rotor or repair the wear parts. To make the connecting screws fasten to prevent loosing or dislocating;
2) Should pay attention to feeding materials whether mixed metals, found that the machine has abnormal sounds,should stop to check.
3) Balanced feeding, prevent blockage, and shall not feed into overgauge materials;
4) Do not open the inspection door for maintenance when the machine not stop completely, in case the rotor and impact plate damaged. Should tighten the screws after adjusting the impact plate;
5) When the equipment overhaul or rotor reinstalled, make sure the rotor that rotating flexible and weight balance. The impact plate should be replaced simultaneously, otherwise the weight of rotor is unbalance to make the machine vibration.