Con Edison's New York steam system is the biggest in the world, but it is packed with problems. Every 20 to 40 feet along the 104-mile pipeline beneath the city's streets, the antiquated rubber and asbestos gaskets and flanges that have joined the segments of the pipes since the system debuted in 1882 are decaying.
To fix the pipes, the New York utility usually deploys a team of 20 men who must stop the bustling traffic, dig down 15 to 20 feet to the concrete-encased steam pipes, and painstakingly weld together the pipe - which reaches temperatures of 400 degrees - one new joint at a time.
This could soon change when Con Edison begins testing an automated labor source. The Welding and Inspection and Steam Operations Robot (WISOR) is a robot the utility hopes will speed up the repair process and save money, which could give it an edge in the new age of deregulation.
At the very least, it is attracting attention from unlikely places. To understand WISOR "you have to understand steam," said Michel Negroponte, a filmmaker who is shooting a documentary about WISOR. "When the first steam pipes were laid in the 1880s, they predated electricity. This is a story that begins in the 19th century and goes into the 21st."
WISOR, designed by Honeybee Robotics, is a 6-foot, 300-pound inchworm, said Jack Pirkey, principal engineer for Con Edison's R&D group. With 12 legs, the robot has two main sections with a telescoping "accordion" area between them.
Although Con Edison will still have to break pavement and drill down to the steam system, it will only have to do this process one time to insert WISOR. Inside the steam pipe, the robot crawls along tiny sled runners until it reaches a gasket. Once there, WISOR uses a balloon to temporarily seal off the pipe from moisture and heat, and then grasps the pipe with its legs to brace itself with a force of 300 pounds per square feet. It quickly grinds up the joint, vacuums up the debris, and then begins welding the piping together. WISOR can grind and repair up to six joints before it must resurface.
"[WISOR means] less excavation, less manpower, and no stopping traffic," said Con Edison spokesman Mike Spaul.
As it trolls through the underground, WISOR drags a 125-foot umbilical cord of camera wires, cooling air, and lights. These appendages allow technicians located above ground to monitor the process and control the welding. They also guard against overheating, the biggest initial obstacle to the project, said Pirkey.
To do repairs now, Con Edison has to shut the system down - stopping hot water and heat service - and lift the scorching pipes out with a crane. "We can't wait for the pipe to cool down completely. So we wait until the pipes cool to about 275 and 300 degrees when we send the robot in," Pirkey said.
The US$900,000 project is part of a major push by Con Edison to prepare for stiff competition when utility deregulation begins in earnest next year.
And Con Edison expects big savings, even before testing begins. So great is its optimism that the company has already contracted the development of a second WISOR. Although Con Edison holds a virtual monopoly on steam and electricity in New York, starting January "people will be able to choose [their utility company]," said Spaul. "And we've got be ready."
