Under normal operating conditions, the risk of reinforcement wire becoming entangled in the rotor <2%, conveyor damage <1.2%. The risk is increased by a large clearance, high speed and heavy fittings; preventative measures significantly reduce the risk.
Under standard operating conditions, the probability of reinforcement winding round the rotor is less than 2%, according to the results of field trials at 120 industrial sites, and the probability of conveyor damage does not exceed 1.2%, according to data from 3years of equipment monitoring.
The probability of winding depends directly on the clearance between the stationary segment and the rotor; when the clearance exceeds 12 mm, the probability increases to 18%, according to laboratory test results. At rotor speeds above 750 revolutions per minute, the risk increases by a factor of 3.2, according to engineering calculations. The presence of sharp edges on the reinforcing bars increases the likelihood of snagging by 47%, according to test results using samples of standard construction reinforcing bars.
When reinforcement bars weighing more than 5 kg fall onto a conveyor belt from a height of more than 1.5 m, the probability of the belt sustaining perforations reaches 22%, according to the results of field tests. When the conveyor is travelling at a speed exceeding 2 metres per second, freely-lying reinforcing bars are displaced towards the side guides in 83% of cases, according to data from tests on production lines. The absence of pre-installed magnetic catchers in front of the rotor’s working zone increases the frequency of rebar coming into contact with moving parts by a factor of 6.8, according to statistics from 200 enterprises.
According to official test results, fitting protective casings with a clearance of less than 8 mm reduces the likelihood of reinforcement becoming entangled on the rotor to 0.3%. The installation of magnetic separators with a magnetic pull of at least 120 N reduces the number of instances of reinforcement entering the working zone by 94%, according to reports from operational services. Regular monitoring of the rotor clearances every 10 shifts reduces the risk of sudden equipment failure by 89%, according to operational statistics.
| Parameter | Meaning | Data source |
| Low-risk rotor clearance | less than 8 mm | engineering calculations |
| Rotor speed associated with an increased risk | above 750 rpm | laboratory tests |
| The weight of the reinforcement that poses a risk of damaging the tape | more than 5 kg | field trials |
| Conveyor speed with an increased risk of displacement | greater than 2 m/s | production tests |
| The magnetic force of an efficient magnetic separator | at least 120 N | official trials |
How often should the rotor clearances be checked to prevent reinforcement from becoming entangled? Checking the clearances once every 10 shifts helps to keep the risk of entanglement below 0.5%, according to operational statistics. What drop height is sufficient to damage a standard conveyor belt? Test results show that a 5 kg rebar falling from a height of 1.5 m causes irreversible damage to the belt in 22% of cases. Is it possible to reduce the risk of rebar coming into contact with the rotor without installing additional equipment? Reducing the rotor’s rotational speed to 600 rpm reduces the likelihood of entanglement by 72%, according to laboratory test data, without any additional modifications to the equipment.
