SU634107A1 - Rate-of-flow meter sensitive element - Google Patents

Description

(54) SENSITIVE FLOWMETER

ELEMENT

The invention relates to a measurement technique and can be used, in particular, in. cement, ore-dressing and other areas; -industry for measuring consumption of:,, mainly Islam.

H;) DseiHD; flow meters comprising a housing made in the form of a rectangular elbow in which a nozzle is placed, mounted on an elastic element, on which a reactive force is generated, a deflecting nozzle and a deforming elastic element. The displacement of the nozzle is proportional to the square of the flow velocity and its density is measured, for example, using a strain gauge sensor 1.

This flow meter does not provide the necessary accuracy of flow measurement due to the fact that the plot of velocities of the flow flowing out of the knee is not symmetrical - areas with large velocities are shifted towards the center of the radius of rounding.

The purpose of the invention is to increase the accuracy of flow measurement.

This is achieved in that it is made in the form of successively located inlet cylindrical section, middle knee-shaped toroidal section and output profiled section formed by part of the cylindrical section of the pipeline bounded above by a plane passing through the chord of the output section and through the point of contact of the knee-shaped part, where the chord length is determined from the ratio a (arcsin - - cosarcsin -), where D is the internal diameter of the pipeline:

 -hord output section; F is a predetermined value.

strength;

QM «: - the maximum value of the stroke;

P is the density measured by the medium. FIG. 1 and 2 are given the scheme of the proposed sensitive element.

The sensing element is made of

0 of an elastic material, such as steel, and includes an inlet cylindrical section 1, a knee-shaped toroidal section 2, and an output shaped section 3.

Section 3 is formed by part of a cylindrical section of the pipeline, bounded above by plane 4, passing through the chord 5 of the output section (be) and through the point of contact with the arc of the smallest radius R of section 2.

The length of the chord 5 (be, b cf) is determined by -from the relation.

.o; 0

(arcsin - cosarcsin -) -y

D D „

where d

- internal diameter of the pipeline;

K - chord of the output section; F - reactive setpoint

strength;

Riaka-maximum flow rate;

I is the density of the medium being measured.

The position of the chord 5 (be, b)

may be lower or higher than horizontal

the axis of the output section of section 3 (see Fig. 1

and 2).

The sensing element works as follows.

The measuring flow passes successively through sections 1 and 2 and exits section 3 to the process tank (not shown in the drawings). In this case, a reactive force arises, deforming the elastic sensing element and is perceived by any transducer.

The effect of the unevenness of the velocity profile is reduced due to the fact that the path in the horizontal section 3 from the high speeds on the diagram is greater than from the small ones, therefore large speeds due to friction decrease more than low ones, and the velocity diagram will look to symmetrical about the axis of the knee.

Since the reactive force depends on the square of the velocity, the deceleration of high velocities in the plot is much more pronounced than the deceleration of low speeds, and the error in the flow measurement will decrease to 3-4%.

Claims (1)

1. Katys G. P. Volumetric flow meters, 35 M.-L., 1965, p. 79, fig. 55.