Hydroelectric, Nuclear

Ontario Hydro replaces gauges for readability

Issue 3 and Volume 100.

Ontario Hydro replaces gauges for readability

Maintenance staff at Ontario Hydro`s 4,300-MW nuclear generating station at Pickering, near Toronto, Canada, had experienced difficulties reading glass gauges on condensate drain tanks and high-pressure feedwater tanks.

The danger of broken glass was also a safety and environmental concern. Ontario Hydro management decided to replace the glass gauges on the boiler circuits with Klinger Magnetic Level Gauges.

Clear view

The magnetic gauges offer clear and accurate readability from a distance through a display that is actuated by an isolated float inside the gauge chamber. Ferrite wafers in the display are linked to each other magnetically.

When the liquid column is empty, the wafers` white faces are on display, but as the float rises and falls within the liquid column, the float`s stronger magnetic field flips the wafers over, showing their red side, which matches the liquid level inside the column.

Point level switches are attached directly to the outside of the gauge by flexible clamps, and are linked magnetically to the float. Set points can be changed by moving the switch up or down. Ontario Hydro also receives continuous level signals through a modular transducer, also attached to the outside of the gauge, providing a 4-20 mA signal.

The gauges are reducing maintenance and providing greater flexibility, according to Ontario Hydro. Complete system shutdowns are no longer required for adjustments. Ontario Hydro has since installed the gauges at two other nuclear power stations.

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Klinger Magnetic Level gauges installed in Ontario Hydro`s nuclear generating station near Toronto, Canada.