Donaldson Co. Inc. topped Wall Street estimates in the second quarter and bumped up its guidance for the remainder of its fiscal year.

The Bloomington-based maker of industrial filters earned 35 cents per share, up 25 percent from 28 cents per share reported in the second quarter last year. That beat the analysts' consensus estimate by 3 cents per share.

"We are pleased with our year-to-date results, which reflect strong execution of our strategic priorities complemented by further stabilization in overall market conditions," said Tod Carpenter, Donaldson's president and chief executive, in the company's earnings release.

For the second quarter ended Jan. 31 the company had sales of $550.6 million and net earnings of $46.5 million, up 6.4 percent and 22.6 percent respectively over the same quarter a year ago.

For the six months ended Jan. 31, sales increased 4.6 percent to $1.1 billion, while earnings increased 36.6 percent to $104.5 million, or 78 cents per share.

Carpenter told analysts on the company's conference call that the quarter was almost entirely driven by gains in the company's engine products segment. Sales in that unit grew 12.8 percent for the quarter. Those results were offset by a 3.9 percent sales decrease in the company's industrial products business.

While the company said it now expects its full-year sales and earnings results to come in above its previously announced guidance, executives are not confident that sustained end market growth is on the horizon.

"We continue to view the overall market conditions as somewhat uncertain," Carpenter said. "Recent restocking is an encouraging sign of stabilization, but the mixed outlooks provided by many large customers combined with the re-emergence of headwinds from currency translation keep us cautious."

Patrick Kennedy • 612-673-7926