SU1763892A1 - Flow transducer - Google Patents

Abstract

Use: to determine the flow rate of a fluid in a pipeline. SUMMARY OF THE INVENTION 1 The sensor has a flow chamber 1 with a window inside which, perpendicular to its longitudinal axis, there is an elastic plate 2, one end of which is rigidly fixed and the other opposite the window of the flow chamber 1. A permanent magnet is mounted on the free end of the elastic plate 2 3. The window of the flow chamber 1 is closed by a plug 4 of a non-magnetic material, on which a semiconductor converter 5 is installed, located outside the flow chamber behind the plug 2 p.

Description

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The invention relates to the field of instrumentation and can be used to determine the flow rate of a fluid in a pipeline.

Known flow sensors, whose work is based on the measurement of the velocity head of the flow using the body located in the measured flow. Such sensors contain a body in the flow of fluid, a transducer of the movement of this body into an information signal, a flow cell of these sensors should include low accuracy, low reliability and bulkiness. The disadvantages are usually caused by the imperfections of the converter used.

Closest to the proposed technical solution is a flow meter comprising a housing, an elastic plate in a fluid flow, means for fastening said elastic plate, a magnetic converter for moving the elastic plate into an electrical signal, a permanent magnet placed on the loose end of the elastic plate. In the indicated flow meter, the movement of the elastic plate under the action of the velocity head of the fluid flow is fixed by several magnetically sensitive elements (reed switches). located in certain places of the body, outside the flow chamber, along the trajectory of the elastic plate. The state of the reed switch (closed or open) depends on the relative position of the reed switch and the elastic plate and characterizes the magnitude of the velocity head of the fluid flow.

The disadvantages of this flow meter are poor sensitivity, low accuracy and cumbersome. The technological feature of the converter on reed switches limits the potential accuracy of the meter due to its large size. The curvature of the flow chamber profile causes laminar flow instability, additional turbulent velocity pulsation occurs, and this leads to a decrease in the accuracy of determining the position of the elastic plate with reed switches. The discreteness of placement of the reed switches creates a zone of insensitivity of the transducer to the movement of the plate and leads to the discrete nature of the measurements. The signal of the converter is not informative (due to the binary view) and requires multichannel processing.

The aim of the invention is to increase the sensitivity and accuracy.

The goal is achieved by the fact that in a flow sensor containing a magnet, a magnetic transducer, a flow chamber with a window, inside which

perpendicular to its longitudinal axis, there is an elastic plate fixed at one end on the chamber wall, and the other free end is located opposite the window, the flow chamber window is closed flush with the wall with a nonmagnetic material plug, a permanent magnet is mounted on the free end of the elastic plate, and a magnet-sensitive transducer is located outside the flow chamber behind the cap, while the magnetic transducer is made in the form of a semiconductor transducer induction constant magnetic field in the frequency pulse signal.

The salient features in the aforementioned combination are the flow chamber with a window, closed with the plug of a non-magnetic material, flush with the wall, the placement of a permanent magnet at the free end so that its magnetic field spreads to the semiconductor transducer, the magnetic transducer is designed as a semiconductor a constant magnetic field induction converter into a pulse frequency signal and its installation outside the flow chamber behind a plug from agnitnogo material.

The indicated set of essential features predetermines the presence of a new property in the current flow sensor, which will increase its speed (reaction rate) to change the flow rate and improve its hydrodynamic characteristics.

FIG. 1 and 2 show the flow sensor circuit.

The flow sensor contains a flow chamber 1 with a window, inside which an elastic plate 2 is located perpendicular to its longitudinal axis, one end of which is rigidly fixed to the chamber wall and the other end

It is located against the window of the flow chamber 1. A permanent magnet 3 is mounted on the free end of the elastic plate 2. The window of the flow chamber 1 is closed flush with a plug 4 of a nonmagnetic material. Behind

plug 4 is installed semiconductor converter 5, the magnetic field of the permanent magnet 3 is distributed to the semiconductor converter 5. A semiconductor converter with a pulse frequency signal allows

to produce direct low-inertia transformation of the intensity of a constant magnetic field into a pulse frequency signal of large amplitude.

The device works as follows. Under the action of the hydrodynamic pressure of the fluid flowing inside the flow chamber 1, the elastic plate 2 with the permanent magnet 3 fixed on it is deflected, and the magnetic field is induced by the permanent magnet 3 and the semiconductor converter 5, which is located behind the cap 4 of non-magnetic material, outside the flow chamber. Magnetic field induction in the gap Permanent magnet 3 - the semiconductor converter B. characterizes the flow value.

The design of the sensor, as compared with the known ones, is significantly simplified, the cost of its manufacture is reduced. The use of a semiconductor converter with a frequency-pulse output signal increases the sensitivity of the sensor and allows continuous flow variation with high accuracy. This makes it possible to increase the speed of control and make it more efficient in systems using a sensor.

Claims (2)

1. A flow sensor comprising a magnet, a magnetic pre-generator, a flow chamber with a window, inside which an elastic plate is located perpendicular to its longitudinal axis, fixed at one end on the wall of the chamber, and the other free end opposite the window, characterized in that sensitivity and accuracy of measurement; the flow chamber window is closed flush with the wall with a plug made of a nonmagnetic material; a permanent magnet is mounted on the free end of the elastic plate and a magnetically sensitive transducer s located outside the flow chamber for the plug. 2. The flow sensor according to claim 1, characterized in that the magnetic transducer is made in the form of a semiconductor transducer induction of a constant magnetic field into a pulse frequency signal. Flow