Thordon supplies Ontario generating station WITH suite of bearings

Thordon Bearings is supplying multiple sets of grease-free bearings to completely replace old technology at the Otto Holden Generating Station on the Ottawa River in Ontario, Canada.

Andritz Hydro was contracted to undertake the mid-life refurbishment of the station’s turbines on behalf of Ontario Power Generation (OPG). Two of the 243MW station’s eight units have now been fitted with Thordon’s ThorPlas-Blue and Thorseal products, via its local distributors RMH Industries in Quebec and Millstream Engineering in Ontario.

Unit 7 was refurbished in 2022, unit 5 in 2023, and unit 8 is next with installation expected in the fourth quarter of 2024. By 2029, all eight of the station’s units will have been refurbished.

Each retrofit involved 262 bearings per turbine including wicket gate bearings and seals, Thorseal linkage bearings, Thordon SXL operating ring wear pads, and servo motor bearings and seals. The bearings being installed have high-end edge loading performance and range from about 100 to 300mm (4-12in) outside diameter.

The servomotors are being made entirely by Thordon distributor RMH Industries, one of the company’s specialties honed over the last 50 years. Gaétan Dionne, RMH Industries’ General Manager, cites, for example, that the company can install Thordon’s bearings on the servomotors using liquid nitrogen in less than a minute.

Thordon’s bearing and sealing solutions were chosen for their reputation for being the highest-performance materials available on the market. A key on-going benefit is that they eliminate the need for regular greasing, thus reducing maintenance costs and avoiding contamination of rivers.

Thordon’s wicket gate, operating mechanism and linkage bearings operate wet or dry and are self-lubricating to ensure performance in limited-motion applications. There is no galling from edge loading caused by minor misalignments or gate deflections. The bearing material is ThorPlas-Blue which is a homogeneous, self-lubricating engineered thermoplastic capable of withstanding operating pressures up to 45MPa (6,527 psi).

Thordon’s Thorseals are made of a proprietary elastomer with no shelf life or degradation of properties over time. Thorseals are available in a wide range of standard sizes or can be quickly machined to custom size requirements up to 1.5m (60in) in diameter.

Greg Auger, Commercial Director at Millstream Engineering, explains that installing the wicket gate bearings requires careful attention to detail.

“It is critical to get accurate measurements of the shaft and housing dimensions before final machining of the ThorPlas-Blue bearings so that they can be sized correctly for proper fit and clearance. During installation, care must be taken to press-fit the bearings to prevent damage, and then they must be protected from risk of damage while other overhaul work continues. Careful measuring of the installed dimensions will help verify that all the large components will assemble correctly.”