This month, Ontario Power Generation (OPG) commissioned the first successfully reversible polytetrafluoroethylene (PTFE) thrust bearing in North America at the 175-MW Sir Adam Beck Pump Storage Generating Station, on the Canadian side of Niagara Falls, according to OPG officials.
Part of the Niagara Plant Group, the OPG facility utilizes Lake Erie as its drainage basin, fed by the Niagara River. Near Queenston, Ontario, the facility began service in 1958 and has six generating units.
North American PTFE Bearing LLC supplied the PTFE-lined, reversible non-eccentricity thrust bearing that has the following specifications:
• Power output 29 MW
• Load on thrust bearing 885,866 kg
• Rotational speed 92.3 rpm
• Bearing type Pivot
• Bearing outer diameter 2,030 mm
• Bearing inner diameter 1,031 mm
• Number of pads 8
• Bearing oil ISO VG 68
According to published scientific data, PTFE is a fluorocarbon solid that is hydrophobic, meaning neither water nor water-containing substances wet PTFE.
OPG contracted Hydro Tech Inc. (HTI) for the design and supply of the new, split-thrust runner, and HTI also oversaw the assembly and installation of the thrust bearing and runner. The bearing is expected to operate at full load with a properly designed safety factor, according to OPG officials.
For the past several years, the generating station’s thrust bearing was not achieving full hydraulic thrust due to recurrent failures. The project involved design and supply of a new improved runner plate and new PTFE bearing pads, as well as other design upgrades and a study of the oil film wedge across the bearing.