Hydro-quebec

Pierre Lavigne

Yves Choquette

Pierre Ducharme

Jean Lavallee

Patrick Mongenot

Jean-Pierre Martin

Leon Veronneau

Alain Houdayer

Pascale Rondot

A gamma monitoring apparatus and method for measuring water equivalent of snowpack over a selected ground area. A detector unit is installed at a given height above the area. The detector unit has a collimator and a scintillator coupled to a photomultiplier tube for detecting gamma rays emitted by naturally radioactive elements present in soil under the snowpack and absorbed by the snowpack in a field of view defined by the collimator. Pulses in a signal produced by the photomultiplier tube are measured and those exceeding threshold energy levels in a number of energy windows are registered as gamma counts. The water equivalent of the snowpack is periodically computed as functions of the gamma counts in the energy windows and the height of the detector unit with respect to ground level. The data representing the computed water equivalent are stored and controllably transmitted for reporting. Soil moisture content is also determinable.

Apparatus and method for monitoring snow water equivalent and soil moisture content using natural gamma radiation

Disclosed is a method for quantitatively evaluating the tightness of the stator wedges of an alternator, which can be reduced to practice without having to remove or dismantle the rotor of the alternator even when the air-gap of the alternator is as small as 10 mm, and which permits to obtain a quantitative evaluation of the compression percentage of the ripple spring holding the wedges in a simple, efficient and reliable manner. This method makes use of a thin flat sensor having one face provided with a recess in which a piston is mounted. This sensor is inserted into the air-gap of the alternator and positioned in front of the stator wedge to be evaluated so that the piston faces this wedge. Thus, a fluid is injected into the sensor to bring the piston to contact and then press against the wedge while the sensor is backed against the rotor. The pressure of the injected fluid which is proportional to the force applied to the ripple spring, is measured together with the displacement of the stator wedge while the pressure is exerted and the so-measured force and displacement are used to determine the tightness of the wedge. The above mentioned measurement of the displacement of the wedge is achieved by measuring the displacement of the piston in its cylinder by means of strain gauge fixed onto resilient blades bearing against the piston. An apparatus for carrying out this method is also disclosed.

Method and apparatus for quantitatively evaluating the stator wedge

Growing community of inventors

Boucherville, Canada

Pierre Lavigne