SU767653A1 - Flow velocity metering apparatus - Google Patents

Description

(54) DEVICE FOR MEASURING FLOW RATE

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The invention relates to. to the field of measurement of motion parameters, it will be useful to measure the flow rate of a liquid or gas.

A device containing 5 sensitive element, mounted on a cantilever beam with two grooves, in which tenso-cells are placed, is known.

This device has a limited range of 10 measurements.

It is also known a device containing a sensitive element associated with an electromagnetic system connected to a constant voltage source 15 and a threshold device | 2

This device does not provide adequate measurement accuracy.

The purpose of the invention is to improve the accuracy of measurements.

For this, the device is equipped with a switching relay, ballast resistance, a trigger with separate inputs, an alternating voltage generator and a trigger generator, while the 25 sensitive element is placed on a magnetic conductive plate mounted for movement, and the electromagnetic system is made in the form of an W-shaped core with three 30

windings connected respectively to the alternating voltage source, through a switching relay to the ballast resistance and a constant voltage source, as well as to a threshold device, the output of which is connected to one of the trigger inputs, the second input of which is connected to the start generator.

The drawing shows a block diagram of the device.

The device contains an electromagnet 1 consisting of a movable magnetic conductive plate 2 and three cores with windings, L / .2 and W, one end of the winding W, connected through the contacts of the relay P to the positive terminal of source 3, and the other end of the winding W (- The negative terminal of this source is parallel to the winding Vi /, the ballast resistance is connected through the relay contacts 4. The winding W of the second core is connected to the alternating voltage generator 5. The winding of the third core is connected to the input of the threshold device B. Output A threshold device is connected to one of the inputs of the trigger 7. To the second input of this trigger, a signal is supplied from

generator 8 run. A single trigger output is connected to the winding of the relay 9. From the output of the threshold device 10, an information signal is output in the form of a sequence of pulses. The flow acts on a plate 11 rigidly fixed to plate 2,

The device works as follows. .

In the initial state, the plate 2 under the action of the flow force is withdrawn from the cores of the electromagnet and the contacts of the relay P are open, and the RC2 coy contacts are closed. With the advent of the impulse of the generator 8, the trigger 7 passes. state one. Relay P contact is closed and the contacts are Shorted. Through the relay contacts P, a constant voltage source 3 is connected to the winding W.

Under the action of the magnetizing force in the first core, the movable plate 2 is attracted. At the moment of pressing the plate, the magnetic circuit closes through the outer cores and the plate, in the winding an emf is induced, the amplitude of which is sufficient for triggering the threshold device 6 The output signal of the threshold device transfers the trigger 7 to the initial state. The contacts of the relay P open, and the contacts P.j close, connecting the winding to the ballast resistance 4. The electromagnetic force stored in the core begins to decrease. The pulling of the movable plate 2 weakens and under the action of the flow it is detached from the cores. At the moment of the detachment of the movable plate ot the cores, the signal at the output of the winding W0 decreases sharply. Threshold device stops working.

The number of pulses transmitted through the threshold device is inversely proportional to the force of the current acting on the plate 11.

767653

The flow rate is related to the force acting perpendicular to the plate area, as follows:

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;

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where p is the density of the medium; the force acting on the plate perpendicular to the flow.

Claims (2)

1. USSR author's certificate number 481839, cl. G 01 P 5/08, 1973. 2. Authors certificate USSR 390448, KJ1. G 01 P 5/06, 1970 (prototype). eleven