Explosion-proof crane installed in Nebraska24 December 2019
AFE Crane, based in Cedar Falls, Iowa, has installed a 5t-capacity Acco explosion-proof crane at a facility in Nebraska, for lifting bulk container bags in a hazardous area.
The project required AFE, a distributor for crane manufacturer Acco Material Handling Solutions, to install a replacement custom motorised underhung single-girder crane and to double the length of the runway from 60ft to 120ft. The confidential site was classified due to electrical equipment installation in an atmosphere with combustible dusts, representing a risk of fire and explosion. The existing crane system was also manufactured by Acco, in 1999.
The new crane is a Class II, Group G, Division I crane with a 14ft span and a 17ft 6in overall patented track bridge. It features an Acco-Wright electric wire rope hoist that offers a lift height of 66ft and 30ft a minute in single speed—this was the fastest possible without sacrificing headroom, said Nick Burns, applications engineer at AFE Crane. The trolley is also single speed, moving at up to 50ft a minute.
Jim Orme, district sales manager at Acco, explained that Class II covers combustible dusts; Group G relates to grain dust; and Division I refers to there being ignitable concentrations of dust present either all of the time or some of the time, under normal operation conditions.
“All hoist components for use in classified areas are marked as such,” said Orme. “The hoist motor, motor brake, conduit fittings, etc. are all labeled for Class 2, Group G, Division I. The Work-Rated hoist model includes an overload device as standard, as well as a Weston-style mechanical load brake as a secondary means of braking.”
Burns added: “We increased the speed for the new hoist due to the long lift. The installation provides high speed and capacity in line with the demands of the facility. Radio remote controls provide further safety and efficiency benefits as the end user can operate the crane and hoist at a safe distance from the hook.”