Explosion-averting Valla
16 February 2009
Pyroban, an explosion protection specialist, carried out the work on the two tonne capacity Valla TRX 20D. The crane operates on rubber tracks at a speed of 2 km/h. As a standard machine, it has many potential sources of ignition, which led the supplier, Valla Cranes UK, to contact Pyroban for a solution.
"Without suitable protection, if a flammable hydrocarbon is present in the atmosphere, it is possible that a mobile crane could be the source of an ignition. Compliance with DSEAR and HSE regulations helps to prevent such a situation at the refineries, which is why Pyroban protects equipment like this," explained Rob Vesty, Pyroban customer services manager.
Controlled through wireless remote, the compact Valla has a horizontal reach of almost 3 m and a maximum height of 4.5 m, with a three-stage boom. Weighing less than two tonnes, the crane is intended to be very compact which proved to be a challenge for Pyroban.
"In this case, the Valla Crane is powered by a small Kubota D722 diesel engine, testament to Japanese miniaturization and perfect for compact vehicles. However, there was limited space for us to make significant modifications to the engine and other components, which was an interesting challenge," said Vesty. "We designed a slim-line cooler to fit comfortably in the engine compartment, without any modification to the bodywork."
Following the pre-conversion testing, Pyroban engineers developed an explosion proof solution for the complete crane. On detection of a gas or vapour the system gives a visual and audible alarm followed by a complete shutdown of the equipment if dangerous levels are reached.
The equipment is for use in a Zone 2 hazardous area where a flammable atmosphere is only likely for very short periods or as a result of a breakdown in process. Tests showed all components of the crane stayed within the specified T3 Class (200°C), said the company.
