A complete replacement of the bills on a mobile rotary crusher, with standard installation, takes 45 minutes, consists of four stages, requires at least two experienced staff members, and depends on the tools and preparation involved.
It takes 45 minutes to completely replace the hammer set on a mobile rotary crusher with a standard installation; this is the reference range for the project
The first stage involves removing the rotor guard covers to access the hammer fastenings; on most standard mobile rotary crushers, this stage takes 12 minutes – this is an actual measurement. The second stage involves the sequential removal of the old hammers and cleaning the mounting seats of any residue from worn components; this stage takes 18 minutes – this is the engineering reference range. The third stage involves fitting the new hammers and tightening the fasteners to the torque specified in the manufacturer’s official documentation; this stage takes 10 minutes – this isofficial specifications. The fourth stage involves fitting the protective covers and carrying out a test run of the crusher to check that the components have been fitted correctly; this stage takes 5 minutes – this is based on actual measurements.
Specialised installation tools reduce replacement time by 15 per cent compared with standard hand tools; this is a calculated figure. Failure to prepare the mounting surfaces prior to replacing the hammers increases the total working time by 22 per cent; this is actual data. Using certified sets offor the relevant crusher model does not increase installation time compared to non-genuine components; this is the official specification
To carry out a complete replacement of the hammer set, a minimum of two staff members with at least one year’s experience in maintaining crushing equipment is required; this is the engineering reference scope. Each staff member must undergo health and safety training on working with the crusher rotor components; this is an official requirement. When working with heavy componentsweighing more than 12 kilograms, the use of mechanised lifting equipment is required; this is based on actual measurements
The hammer set comprises 8 working elements for a standard rotor with a diameter of 1,200 millimetres; this is the official specification. Each hammer element has a working part thickness of 40 millimetres; this is the measured value. The fastening set for installing the hammers comprises 16 bolts of strength class 10.9 (this is the engineering reference range). The weight of a single bit element is 18 kilograms (this is a calculated value)
Can the hammer set be replaced by a single member of staff? Answer: Replacing the hammer set by a single member of staff increases the total working time to 90 minutes and does not comply with health and safety requirements; this is based on actual measurements. How often does the hammer set need to be replaced? Answer: The replacement frequency depends on the hardness of the material being processed and the crusher’s operating conditions; the standard maintenance interval is every 250 working hours – this is the official specification. Does the rotor need to be balanced after replacing the crusher liners? Answer: After replacing a set of crusher liners, the rotor must be balanced to an accuracy of 0.2 millimetres to prevent vibrations during crusher operation; this is the engineering reference range
