Outside the place where Tom Knox votes in Center City, two campaign consultants yelled at each other while demonstrators held signs proclaiming "Knox=Shark."

In South Philadelphia, workers for Michael Nutter blocked the Knox campaign from handing out sample ballots because they lacked the required disclosure that Knox had paid for them.

In West Philadelphia, rivals said that radio personality Mary Mason had torn down signs supporting Nutter. The District Attorney's Office said it could not prove that Mason had done that, but she was given a talking-to anyway.

These episodes, some machine malfunctions and a few other problems aside, Philadelphia's primary ran pretty smoothly yesterday - kept on the rails by a large contingent of workers from a crowded field of mayoral candidates and an unusually large showing of nonpartisan observers.

Zack Stalberg, president of the Committee of Seventy election-watchdog group, said it fielded 500 volunteers to monitor the primary. This was a 10-fold increase from some recent past elections, he said.

"This is definitely the biggest operation that we've ever run," Stalberg said at midday in the committee's offices as he watched volunteers answer its emergency phone lines.

As it happened, the phones were relatively quiet. The election turned out to be a "mellow" affair, as John McGarry, a judge of elections in Center City, put it.

To be sure, there was an episode involving a shotgun - though it wasn't really related to the election.

A man upset at losing a pickup basketball game brandished the gun on the playground of the Max Myers Playground in the Northeast - a polling place in the 54th Ward.

The man left without firing the gun. But the incident unnerved and distracted election workers, who were later interviewed by city detectives.

Although most polls closed on time, the day's lengthy ballot contributed to long lines and delays at some precincts.

At 7:45 last night, Julia Stein was looking at a two-hour wait in Mount Airy. She said the delay gave her a chance to catch up with old friends. "I'm not unhappy at all," Stein said. "I'm happy to stand here."

In one controversy at midmorning, Common Pleas Court Judge Harold M. Kane barred Knox supporters from handing out the flawed sample ballots to voters at 1021 S. Fourth St.

Kane, sitting in Election Court in City Hall, acted in response to a complaint from Nutter workers.

In the morning verbal face-off, the warring consultants were Knox foe Ken Smukler and Knox ally Frank Keel, who accused each other of dirty tricks.

They got into it after four men carrying giant "Knox=Shark" signs stationed themselves outside the polling place on 21st Street. The signs referred to Knox's former ownership of a bank that once made high-interest "payday" loans.

Smukler said that the sign-carriers were paid by his so-called "527" group, Economic Justice Coalition for Truth, that has tried to attack Knox during the campaign. Before joining that group, Smukler resigned from mayoral candidate Bob Brady's staff after Keel disclosed that Smukler had tried to create organizations to attack Knox.

In West Philadelphia, a dispute arose in the 52d Ward, home to Michael Nutter. Rivals complained that Mason, while serving as a judge of elections, had torn down signs for Nutter and other candidates she opposed.

In an interview with The Inquirer, Mason said she had not pulled down any signs.

Assistant District Attorney Peter Berson said that Mason would neither admit nor deny ripping down the signs.

"She talked around it," said Berson, an elections specialist with the District Attorney's Office.

Berson said staff from his office twice drove out to Mason's precinct to speak with her.

"We talked to her about a whole range of topics, explained to her the rules of the road," Berson said. "We haven't received any complaints since."

Contact staff writer Craig R. McCoy at 215-854-4821 or cmccoy@phillynews.com.

Contributing to this article were Inquirer staff writers Marcia Gelbart, Patrick Kerkstra and Michael Vitez.