Concrete production is big business in the UK, with around 1,000 ready-mix sites and a large number of facilities producing precast concrete structures. In these environments fast, safe access to the mixer is important as set concrete can easily cause blockages if not regularly washed down.
The World Business Council for Sustainable Development’s ‘Health and safety in the cement industry: Examples of good practice’ recommends that when access to hazardous areas is required during normal operation, interlocking guards should be considered the number one safety option. Regulation 11 of the HSE’s ‘Provision and use of work equipment regulations 1998 (PUWER 98) (ACOP 2008)’ suggests fitting interlocked guards to protect operators from the dangerous parts of machinery.
There are three main ways trapped key interlocking systems can provide an efficient safety solution for the cement mixing industry:
- Trapped key interlocks ensure operators follow a strict procedure.
- Isolation of the power supply can be coupled with a motion-monitoring device which grants access to the mixer as soon as safely possible. In contrast to fixed-time delay systems, which can overcompensate rundown times for lighter loads, a motion-sensing system reduces downtime for equipment with variable rundown speeds.
- Trapped key interlocks are highly durable, have a longer product life and require less maintenance than alternative safety systems. As a result, the machinery to which they are fitted suffers less downtime and so overall plant utilization is increased.
The robust mechanical nature of the locks and keys is well suited to the harsh environment of a concrete plant, as well as being resistant to regular wash downs.
By: James Seel, Marketing Assistant, Castell Safety International Ltd.