The carillon of Hyde Park fell silent this summer, but its enormous bells swung through the air last week, beginning a long journey to a Dutch foundry to be cleaned and retooled.

The trip marks the first major cleaning for the bells since their installation in 1932, according to the Rockefeller Memorial Chapel at the University of Chicago.

"Technically, this is the largest instrument to be constructed at one time anywhere in the world," Lorraine Brochu, assistant to the dean of the chapel, said with a smile. Riverside Church in New York City boasts two more bells in its carillon - a mechanical instrument that allows a piano-like keyboard to play huge, hanging bells - but those who keep track of such records note that many of Riverside's bells have been added through the years.

Rockefeller Chapel's carillon consists of 72 bells, 46 of which will be cleaned and repaired by the Royal Eijsbouts foundry in Asten, Netherlands, according to Coen Feijen, the company's chief engineer.

"Over time the bells become dented or misshaped," Feijen, 36, said as he oversaw the removal of the bells. "We will take all bells between 6 pounds and 2,700 pounds," he said, though the very largest bells will stay in the tower.

Brochu said the bells, originally made in Croyden, England, were headed by ship to the Netherlands for the best maintenance and retooling in the world.

"We will try to scrape 'England' off the bells so they say 'Holland' when we bring them back," joked Dirk Fransen, a 28-year-old engineer at Royal Eijsbouts.

"Just as long as they're back in time for our June 8 concert," Brochu said, referring to the premiere of the improved bells at the Hyde Park Art Fair next summer.

Rockefeller chapel began renovations on the 100-ton carillon in August, and Bergland Construction is overseeing removal of the bells, as well as repair to the masonry and steel skeleton of the chapel's tower.