Number of hammers arranged

The number and arrangement of hammers on the rotor of the hammer crusher affect the balance of the rotor, the distribution of materials in the crushing chamber, the uniformity of the wear of the hammer and the working efficiency of the crusher.

The number of hammers is measured by the number of hammers per unit rotor width (hammer density). If the density is too large, the rotor starting torque will be large, the material will be hit many times, and the output of kWh will be reduced. Will be affected.

The arrangement of hammers refers to the relative positional relationship between each group of hammers and the same group of hammers on the rotor. The arrangement of hammers is best to meet the following requirements: when the rotor rotates, the movement trajectory of each hammer does not repeat; the material will not shift to one side under the movement of the hammers (except for special requirements); The rotor is balanced in force and does not vibrate during high-speed operation. Figure 5-9 is a flat plan view of several common hammer arrangements. They show the relative positions of the four groups of hammers on the rotor.

a. Spiral arrangement b. Symmetrical arrangement c. Staggered arrangement d. Symmetrical staggered arrangement

1. Spiral arrangement (Figure 5-9a) This is the simplest arrangement, divided into single spiral and double spiral. Its hammers are evenly distributed and the trajectory is not repeated. However, when the rotor rotates, the force is extremely uneven, and the entire device vibrates greatly, and the movement trajectories of all the hammers form a spiral line, which pushes the material to the side of the crushing chamber, resulting in uneven force on the hammers and material deviation. The wear of the hammers on one side increases. Therefore, this arrangement is only applicable to small crushers with very small power and low speed, as well as those required by the process.

2. Symmetrical arrangement (Figure 5-9b) Corresponding to the two sets of hammers installed symmetrically, therefore, the centrifugal force on the symmetrical two pins on the rotor can be balanced with each other, the rotor runs balanced, the materials in the crushing chamber are evenly distributed, and all the hammers wear synchronously. At the same time, there are few types of spacers required for this arrangement, and the installation of the hammer is simple and convenient. At present, the FSP series and SFSP series hammer mills used most in domestic feed production use this method. However, the trajectories of hammers that are symmetrical to each other are repeated, so that to maintain the same hammer density, the number of hammers required will increase exponentially.

3. Staggered arrangement (Figure 5-9c) There are two kinds of single-chip and double-chip. The trajectories of the staggered hammers are uniform and do not repeat. The centrifugal force on the symmetric pin balances with each other, but the materials are slightly offset during work, and there are many types of spacers required for hammer positioning. Convenience.

4. Symmetrical staggered arrangement (Figure 5-9d) In theory, this is the best arrangement. Not only the trajectory is uniform but not repeated, the material does not move, and the center of the four pin shafts is on the same plane. The symmetry axes are balanced with each other, so the balance performance of the rotor is good.