Untitled record

FRENCH REPUBLIC

MINISTRY OF INDUSTRY

INDUSTRIAL PROPERTY SERVICE

PATENT OF INVENTION, A / · o

PV n ° 862.642 V * \ ^? '1N ° 5Î297.828

International classification: AG 01 f

Improved pendulum applicable to the mea surement of a fluid current and measuring device using such a pendulum.

ELECTRICITY OF FRANCE, National Service residing in France (Seine).

Requested on May 24, 1961, at 1 p.m.¹¹ 59^m, in Paris. Issued by order of May 28, 1962.

(Official bulletin of industrial property, n ° 27 of 1962.) (Patent of invention whose delivery was postponed in execution of article 11, § 7, of the law of July 5, 1844 modified by the law of July 7 April 1902.)

We know that we can measure with a pendulum the speed and direction of a fluid current. If we immerse in such a current the heavy mass of a pendulum it moves in the direction of the current and takes a position of equilibrium which is all the more distant from the point of rest as the speed of the current is greater ; the spacing of the pendulum therefore makes it possible to know the speed of this current.

The method recalled above which is used in particular in hydraulic models has, however, so far the disadvantage of being marred by errors due to the oscillations which occur around the equilibrium position and which are of the more important the higher the current speed.

The present invention due to the National Hydraulic Laboratory relates to a pendulum intended for the measurement of a fluid current and perfected so as to remedy this drawback.

The pendulum according to the invention is characterized in that its heavy mass, intended to be immersed in the flow of fluid to be measured, comprises a tail and stabilizing fins.

The present invention also relates to a device for measuring a current of fluid using a pendulum of the above type or of a similar type.

The device comprises in combination with the pendulum, a support for the latter, a first reflective element fixed on the pendulum wire, a second reflective element disposed vertically from the point of attachment of the pendulum to the support, a projector for lighting these elements reflectors, and a camera for photographing said reflective elements.

We have described below by way of nonlimited example

- 41372 shows an embodiment of the invention with reference to the attached drawing in which:

Fig. 1 is a perspective view of the pendulum;

Fig. 2 is an elevational view of the device for measuring a flow of fluid;

Fig. 3 is a plan view of this device.

In the drawing, the heavy mass of the pendulum, which is hung on a wire 1, comprises a vertical tail 2 and horizontal fins 3 arranged on either side of this tail, all of these fins forming a U in the plane median of which is the empennage. Furthermore, it comprises a relatively heavier element 4 which is intended to balance the weight of the tail and the fins with respect to the attachment point 5 of the wire 1. The assembly is determined so that the weight has an average density close to that of the fluid to be measured.

The device for measuring a fluid current which is shown in FIGS. 2 and 3 and which is applicable in particular on maritime scale models where it makes it possible to establish on the curves variations in the speed and direction of the currents at locations chosen on the model, includes a pendulum which is of the type described here above and whose weight is generally designated by reference 6.

The pendulum wire 1 is hung on a support 7 and carries a reflective paper 8 forming a mirror. A reflective paper 9 is also placed at the point of attachment of the wire 1 to the support 7.

Above the pendulum in the rest position is a camera 10 next to which is placed a projector 11 illuminating the reflective papers 8 and 9.

The heavy mass 6 being placed in the stream of liquid 12 to be measured, the photograph of the reflective papers 8 and 9 makes it possible to know on the one hand

Price of the booklet: 2 NF [1,297,828] - the direction 13 of the current which is given by the direction of displacement of the pendulum and on the other hand the speed of this current by measuring the displacement D of the reflective paper 8.

It goes without saying that the invention is not limited to the embodiment described and shown but on the contrary covers all the variant embodiments and applications.