Coil springs supporting crushing and screening equipment have to put up with a lot in life.
Not only are they expected to function reliably in often wet and corrosive environments, but also they have to cope with rapidly changing loads and sudden severe impacts.
Not surprisingly, many suffer trauma as a result. One problem is noisy coil chatter as loads change. Under constant battering, coils may also suffer spring set, or permanent compression below their original design height. This means they do not perform to their original specifications.
In the worst cases, they break. Then there is not only downtime to consider, but also maintenance workers have to get right into some of the most inaccessible entrails of industrial equipment.
“And even when they are functioning perfectly, the row produced by conventional coils can be a hazard to hearing – not to mention sanity,” says actuation and isolation specifier Simon Agar.
Mr Agar, who has 15 years experience in his field with Air Springs Supply Pty Ltd, is developing the use of quieter and more efficient actuators and isolators, including proven rubber-and-fabric Marsh Mellow springs from Firestone.
Marsh Mellows are in use world wide in applications such as shaker screens, crushing equipment, vibrating bins and other vibrating equipment used in applications including food processing, manufacturing, materials handling, quarries, mineral processing and primary product processing.
While no one spring design is ideal for all applications, Marsh Mellows offer considerable advantages over both conventional coils and solid rubber springs for many tasks, he says.
“They operate silently with more spring travel and greater load capacities than conventional coil springs, while outperforming all-rubber alternatives in many areas, such as greater load capacity and more compact size for comparable tasks.
“The cylindrical Marsh Mellow springs are constructed of a solid rubber core with a hollow
centre and several plies of fabric-reinforced rubber as an outer cover. The plies provide the springs with stability as well as a consistent cylindrical shape.”
One of the big advantages of Marsh Mellows is that they offer constant vibration isolation with changing loads. Their variable spring rate allows for a nearly constant natural frequency under the impact of such loads.
And because of the Marsh Mellows’ greater deflection capabilities – and the load-carrying influences of the fabric reinforcement – it can carry a greater load when compared to a solid rubber part of the same modulus and dimensions.
Air Springs Supply Pty Ltd
Ph: 02 9807 4077