Balance Vibration Technologies, Inc.

Energy costs for rotating equipment are many times higher than maintenance costs. Even a small percentage energy savings can quickly exceed the total cost of a lubricant purchase.

Production employees at a paper mill had attempted to put a higher pli load on a control crown (CC) roll in the calendar stack due to some new grades of paper now being made. The limiting factor had been the temperature rise of the oil in the CC roll with increased pli. The oil temperature was causing concern as it was reaching a level at which the oil viscosity and lubrication limits were being compromised. The plant had never been able to go above 650 pli.

Lubrication quality was determined to be the factor limiting equipment performance. Reliability staff made the decision to seek a better performing lubricant in an attempt to resolve the issue. They elected to upgrade from their current brand name petroleum-based paper machine oil to a high film strength paper machine oil. The high-performance synthetic lubricant allowed them to increase machine speed, reduce temperatures, and achieve a pli level they had never been able to attain: 873 pli (Table 1).

	Conventional oil	High- performance synthetic oil

Machine speed average	1,600 fpm	1,780 fpm
Oil temperature to roll average	130° F	130° F
Oil temperature from roll average	194° F	194° F
CC roll PLI average	650 PLI	873 PLI

After 15 months, the oil condition had remained exceptional, with iron wear metals remaining nearly nonexistent. The vast improvement in equipment operation created annual energy savings of $27,945. Energy savings were calculated using the data in Table 2. The energy savings alone exceeded the total cost of upgrading the lubricants within a few months and created substantial cost savings long-term.

Data

	Gallons oil flow through roll per minute	11.8
	Temperature difference between standard and upgraded oil	32
	Specific gravity (SG) of petroleum-based oil	0.893
	Specific heat (SH) of petroleum-based oil	0.505
	No.of BTUs to raise one lb of water 1° F	1
	No. of BTUs per hour to equal one hp	2,547.16
	Annual energy cost per hp at mill	$213
	Weight gallon of water	8.345

Calculation

11.8 gpm x 8.345 lb / gallon of water x 0.893 SG = 87.93 lb / min 87.93 lb / minute x 60 minutes = 5,275.8 lbs / hr (oil flow) 5,275.8 x 32° = 168,825.6 BTU / hr 168,825.6 / .505 SH = 334,308.11 334,308.11 / 2,547.3 = 131.2 hp 131.2 hp x $213 cost per hp = $27,945 in annual energy savings

Lubrication management encompasses all of the lubrication practices and procedures attentive to properly storing, applying, monitoring, and taking care of the selected lubricant. It includes making sure the right oil gets into the right equipment in the right place in the right amount at the right time. It also encompasses used oil analysis programs, visual inspections and maintenance of fluid levels, timely oil changes, and attention to contamination control from water, etc.

The elements that constitute good fluids management are far too extensive to address in this article, but they are essential to achieving quality lubrication. It is important to note however, that good lubrication practices are not a substitute for selecting high quality lubricants with the performance properties necessary for optimum performance in equipment.

Good lubrication practices simply cannot make a poor lubricant become a high-performance lubricant. Good lubrication practices are important in helping to preserve the original lubricating properties of the selected oil.