Electric power is always in demand, so coal-fired power plants are always on duty. These plants burn coal that has been pulverized – and require multiple coal pulverizers. Pulverized coal produces fewer emissions and more efficient burning.
Lovejoy was enlisted to help a power plant that was having costly downtime, maintenance and material expenses from the v-belts on its coal pulverizer drive system.
The pulverizer was using a 10 groove 5v cross section banded belt drive. Normal, daily operations allowed these belts to stretch over time. The sheaves also wore quickly.
“Due to warm ambient temperatures, stretching occurs quickly and weekly tensioning of the v-belts is common,” says John Ernst, Lovejoy National Sales Manager. “Improper tension results in belt slippage which also wears out the large sheaves. Both are expensive and time-consuming to replace.”
To eliminate this problem, a Lovejoy Heavy Duty Tensioner was installed to manage the tension on the v-belts. This tensioner was designed to address situations involving larger horsepower motors, in this case, the coal puliverizer’s 300-hp belt-drive.
The Lovejoy Tensioner automatically self-adjusts to compensate for normal stretching and to absorb shock loads. Its rubber-torsion spring uses four, tough elastomeric inserts to isolate the tension arm, while providing constant tensioning of the v-belts.
The sliding base system, used previously, required the maintenance team to slide an idler pulley along the mounting rails, losing precious production time. The Lovejoy Tensioner does not replace the existing motorbase, but instead utilizes fabricated arms and an idler pulley between the arms to apply the correct tension to the belts.
“We were able to leave the existing motorbase intact, setting the alignment and allowing just enough room to slide the new belts over the sheaves,” says Ernst. “Then, we applied the Lovejoy Tensioner against the belts to give them proper tension. Proper tension reduces downtime and stops belt slippage.”
The Lovejoy Tensioner is easy to install and maintain. The motor is set so that, when releasing tension, the belts can be taken off and new belts reinstalled without moving the motor. This eliminates the need for monthly maintenance. Twice a year, they lubricate the idler ball bearings.
The Lovejoy HD Tensioner keeps chains and belts taut, which eliminates slip and vibration and prevents uneven drive surges and power loss. It also can increase motor life by protecting the radial loads on the output shaft bearings. The elastomeric elements absorb shock loads and, in addition, decrease vibration and noise levels – an important OSHA consideration. The predicted lifespan for the Lovejoy Tensioner is ten to 15 years.
Find out more about Lovejoy, ask IBT.