Where cranes are subject to arduous conditions – heavy lifts, high intensity operations, frequent motor starts, high speed of operation or greater height of lift – heavy duty open winch hoists fit the bill.
Equally, there are some industrial processes that have complex and unusual handling requirements, such as dual or multi-point lifting or very special safety needs, thus, excluding standard hoists.
The biggest markets for open winch hoists are the USA and Canada, where they are commonly referred to as built-up hoists.
The open design provides for easier assembly, inspection and maintenance and avoids crowding of the components for better cooling. This may be especially significant where the hoist is used in hot applications such as handling ladles, castings or ingots. The open plan design also allows for an almost unlimited combination of components to provide customised solutions to individual lifting applications. This is especially relevant when the crane is integrated into a particular industrial process allowing special equipment such as grabs, magnets and other lifting devices to be incorporated.
As Al Horgan, Whiting crane application group supervisor, says, “The heavy industrial manufacturer will typically require a more robust overhead material handling system, wherein the crane becomes an essential and integral part of the facility’s production throughput.” Minimising downtime and maximising reliability and maintainability are major considerations in the purchase of such heavy duty units.
A few of the markets key players have outlined their take on this section of the marketplace.
UK firm Street Crane’s offering in this category is the VX heavy duty open winch hoist. Available in capacities up to 200t and for EU classifications up to M8 (US Class F), this workhorse is generally used in steel mills, foundries, heavy-end engineering and other demanding applications.
Managing director Andrew Pimblett says: “In most cases we sell heavy duty open winch hoists where neither we nor our competitors have a series built hoist to meet the requirement. However, we do have a number of large customers who insist on open winch hoists regardless in the knowledge that they are getting a product that is both more robust and reliable.”
The high strength open chassis provides a versatile platform within which different lengths or diameters of barrel can be fitted to suit customer needs. Twin scrolled barrels are typical and achieve a vertical lift path, with zero hook drift, for greater load safety and stability and less chance of product damage. Deep groove double scrolling and flanged barrels obviate the need for rope guides, which can be a problem where rope deviation is unavoidable.
Different motor and gear box configurations can be used to achieve the desired speed of operation and duty rating to meet customers’ specific process needs. Characteristically, in addition to electrical braking using flux vector, Street VX hoists have failsafe mechanical brakes operating on the first gearbox reduction shaft. This means that the load is safe even if the motor fails or is removed.
There are many examples of Street’s expertise in this area. At Fujairah Power Station in Dubai they provided two 125t cranes for the turbine hall; these facilitate more efficient dismantling and re-building of the turbines during the scheduled maintenance programme. Via North Queensland Cranes, Australia, it supplied four 30t hoists for use on draglines to achieve ultra short hook approaches. For Corus in the UK, Street recently supplied two 30t cranes with special coil handling equipment and for Aluminium Bahrain it has recently supplied two dual hoist 20/8t hot metal cranes for continuous use in a high temperature environment where there is also a permanently high electrical/magnetic flux.
Demag Cranes & Components has developed an open winch hoist as a module for its process crane programme. The multi-purpose winches (MPW) are hoisting units constructed from mass-manufactured components and system subassemblies.
The variable combination of these elements enables “the realisation of maximum technical and economic benefit,” it said.
Advantages:
– high level of standardisation with a high degree of flexibility.
– good for stockage of spare parts.
– clear interfaces for easy maintenance and controlling.
– compact arrangement of all components.
– reachability of the components.
The capacity of one MPW is 170t, in special cases up to 200t.
The MPW was developed and designed as universal lifting equipment for different industries. Examples for running Demag cranes with MPW are in the paper, automotive and steel industries.
Our success “hinges around our built-up hoist,” says Brian Shapiro, Whiting vice-president of business development.
Its built-up hoists are typically comprised of a foot-mounted hoist motor and brake coupled to a 2, 3 or 4 reduction, horizontally split, gear reducer, which either directly drives the hoist’s wire rope drum, or indirectly drives a much larger hoist drum through one or more external, guarded gear reductions.
In the last three years alone, Whiting has designed custom built-up hoists in the 5-300t range. “While the need for a built-up hoist is readily apparent at the higher end of the range, users at the lower end clearly have a choice,” it points out. Recent Whiting examples at the lower tonnages include 5t hoist units used in the handling of nuclear waste.
Another recent application at the very low end was a 12t hoist for a crane Whiting supplied for a refuse-to-energy plant. The customer uses the crane around the clock where downtime will severely impact the operation.
The bulk of Whiting’s built-up applications are in the 15-125t range, although recently the percentage of applications in the 125-300t range has been growing.
Like many manufacturers of these units, Whiting has designed and built cranes with a rated load up to and beyond 1,000t. Cranes with built-up hoists typically provide a 20-50 plus-year service life. In several industries, such cranes have even been modernised after only 75 to 100.
Whiting says end users should be aware of the true characteristics of a hoist. The term “built-up” is used by some manufacturers even though their product offering may be a “hybrid” incorporating a lot of package hoist elements, it says.
Konecranes offers the pre-engineered SM winch for heavy duty up to 63t. For higher capacity or special rope reeving, it can build a tailor-made winch up to 400t by using in-house manufactured standard heavy duty components.
It says demand largely comes from steel mills, scrap yards, hot metal plants, steel processing, hot rolling, cold rolling and plate finishing lines. For example, the large capacity of such lifting equipment lends itself to general manufacturing, while the petrochemical market requires continuous operation at high capacity.
Konecranes says last year was “good” for process cranes but warns: “The turmoil in the economical environment is affecting everything.”
American Crane & Equipment Corporation has expanded its current product line to include standardised industrial hoist machinery meeting Class D and E requirements. All equipment is designed per Crane Manufacturers Association of America (CMAA) specifications.
Its built-up hoist is available in capacities up to 300t and is designed for high speed and heavy duty service. The hoist features, among other things, hardened steel wheels, helical travel drive gearing, forged steel hook, hardened steel sheaves, and double grooved drum for true vertical lift.
