An increase in heavy-duty truck production and new contract wins in China helped Donaldson Co. report strong third-quarter earnings that were up more than 16 percent.

The Bloomington-based technology-driven filtration company reported sales of $700 million, up 15.1 percent from the $608.2 million it recorded in the same period last year. Currency translations contributed 6 percent of the gain. Earnings for the quarter were $69.9 million, or 53 cents a share, a penny above analysts' expectations.

"We are pleased to have delivered another quarter of strong sales growth in both [major] segments, reflecting benefits from consistent execution of our strategic priorities combined with favorable market conditions," said Donaldson Chairman and CEO Tod Carpenter in a news release.

Sales in the company's engine products segment increased 16.4 percent; the industrial products segment saw an increase of 12.4 percent over the year-ago periods. Increasing production of heavy-duty trucks meant more sales of Donaldson filtration products. The new contract wins, officials said, will produce ongoing revenue.

"We've been actively planting seeds with new program wins for many years now," Carpenter told analysts on the company's quarterly conference call. "As the market turns, we are seeing an outsized benefit from those past wins."

Momentum allowed Donaldson to raise its forecast for the remainder of the fiscal year, which ends July 31. The company now expects year-end sales to increase about 15 percent, up from the prior range of 13 to 15 percent, and adjusted EPS to range from $1.97 to $2.01.

One potential downside of the report for investors: Gross margin dipped 60 basis points in the quarter due to inflation and rising costs of raw materials, particularly steel and media. The company said expense controls and price increases initiated during the quarter minimized the margin decline and is expected to be beneficial to margins going forward.

Shares of Donaldson closed at $47.20, down 42 cents or less than 1 percent. Year-to-date shares are down 3.5 percent.