TECHNICAL LIBRARY

 

Kason Gyrators – Unsurpassed On-Stream Reliability At Lower Operating Cost Per Hour

Gyrators, the heart of the circular screener, must be reliable, particularly in continuous service. Most people not familiar with gyrators assume more horsepower gives greater reliability and, for other applications, that may be true. But not in the case of gyrators driving circular screeners. Electrical problems in these gyrators are a rarity because once the unit is up to operating speed, the power requirements are minimal. That is, at the operating speed, one must only provide enough energy to move the process material within the screener, which is negligible because screen decks are lightly loaded, and also to overcome minor mechanical losses such as the hysteresis losses of the springs. The point where torque is required is when the unit is starting up and must drive through the resonant frequency of the machine. This low frequency torque can be attained by winding for the higher torque required at low RPM and maintaining low horsepower at operating speeds, or simply wiring additional horsepower for the unit at all speeds. Kason has chosen the former approach to conserve energy and thus assure lower operating cost.

When failure of these units does occur, it is virtually always the upper bearing that fails due to the heavy loads imposed by the top eccentric. Kason design engineers insure reliability by specifying oversized bearings designed specifically for vibrating screeners coupled, with special high pressure lubricants which have demonstrated performance over many years of in-plant operation. Paying close attention to design details and lubrication requirements led Kason to offer two different high pressure greases - one for bearings 70mm or below and one for 80mm and above. Adjusting the lubricant specification to closely match the bearing operating requirements has assured on-stream reliability in the screener under the most severe process conditions.

Kason design engineers tend to be conservative and this can best be seen by comparing the weight of Kason gyrators to competitive units:

Kason GyratorsCompetitive Units
1 hp - 190 Ibs.
2.5 hp - 1871bs.
2 hp - 300 Ibs.
5.0 hp - 187 Ibs.
3 hp - 420 Ibs.


Kason has designed these gyrators with the end user in mind. Unlike other gyrator suppliers who require complete end bell assemblies to be returned to their plant for repair, the Kason gyrator is designed so it can be repaired at any quality motor facility or on site if such capability is available.

Continuous review and evolution of the gyrator's design assures tomorrow's performance will be better than today's which is better than yesterday's.

Screen Tips - Volume 7, Number 2 Spring 1992