Pump, filter and valve maker Pentair Ltd. reported Tuesday that tough oil and gas markets caused a 3 percent drop in first-quarter sales.

But cost cuts and post-merger synergies propelled adjusted earnings up 26 percent to 73 cents a share, which was in line with analysts' expectations.

Revenue fell to $1.7 billion, shy of the $1.79 billion expected on average by Wall Street analysts. Including one-time items, unadjusted earnings rose 129 percent to $118 million.

Pentair CEO Randall Hogan said in a statement that overall results were strong.

"We were pleased with our strong double-digit earnings growth in the quarter, which was driven by the continued momentum in productivity and synergies" after the 2012 merger with Tyco Flow Control, he said.

Hogan also said Pentair's beverage and residential and commercial businesses "delivered strong sales performance," helping to offset declines in energy and infrastructure units.

Pentair's valves and controls division saw sales fall 9 percent to $535 million as oil, gas and mining customers reduced orders. Upticks in food and beverage and commercial processing equipment helped offset the drop from resources-related clients.

Processing equipment division sales rose 5 percent to $418 million amid strong orders from food and beverage firms and from commercial and residential customers. However, the company's flow technologies division saw sales drop 7 percent to $364 million during the quarter.

The company is based in Switzerland but managed from offices in Golden Valley.