SU1262291A1 - Device for determining media boundary - Google Patents

Abstract

A DEVICE FOR DETERMINING A SECTION BORDER OF ENVIRONMENT containing a pulse generator, a level sensor made in the form of a spiral placed in a sealed, non-magnetic, electrically conductive body connected to an indicator, and a float with a magnet, characterized in that, in order to extend the measuring range and simplify the design, the winding the helix is deposited on a dielectric tube filled with ferromagnetic fluid and connected to a generator. (L to o | C | C; o

Description

The invention relates to instrumentation and can be used to build meters and regulators of the liquid level in devices of automation and telemechanics in the oil and chemical industries.

A device for determining the interface between media, containing a sensor in the form of an electromagnetic delay line, a pulse generator and a measuring unit. The sensor is a spiral, placed with a gap in the housing, made in the form of a coarse, open from the bottom and top, which forms a uniformly distributed capacity of the delay line, the measured medium through the lower opening of the housing fills the gap between the spiral and the housing. The level is determined by measuring the time interval between the probe pulse and the pulse reflected from the inhomogeneity in the delay line that occurs due to a change in capacitance at the media interface [1].

The disadvantage of this device is the influence of environmental parameters on the accuracy of determination, since the medium is an element of the delay line.

Closest to the invention in technical essence is a device for determining the interface between media, containing a pulse generator, a level sensor made in the form of a spiral placed in a sealed non-magnetic housing and wound around a magnetic circuit, at the end of which a piezoelectric element connected to the generator is mounted, an annular float with magnet and indicator [2].

The disadvantages of the known design are the complexity due to the presence of piezoelectric elements, and a limited measurement range, determined by the size of the bar magnet, on which the spiral is wound.

The purpose of the invention is the expansion of the measuring range and simplification of the design.

This goal is achieved by the fact that in the device containing the pulse generator, the level sensor, made in the form of a spiral, placed in a sealed non-magnetic electrically conductive housing connected to the indicator, and a float with a magnet, the winding and spirals are applied to a dielectric tube, hermetically sealed and filled with a ferromagnetic liquid, and connected to a generator.

The drawing shows a diagram of the proposed device.

The device comprises a hermetically sealed housing 1 made of non-magnetic electric wire .ό material in the form of a pipe. A dielectric tube 2 filled with ferromagnetic fluid 3 is located inside the casing with a gap. A spiral 4 is wound around the tube 2, forming together with the casing 1 an electromagnetic delay line. On the outside of the housing 1 is installed a float 5 with a magnet 6.

The electrical part of the device contains a pulse generator 7, which generates a periodic sequence of probe pulses, and a level indicator 8, which provides a measurement of time proportional to the level of medium separation.

The device operates as follows.

An annular float 5 with a magnet 6 moves along the housing 1, the position of which coincides with the interface. In the magnetic field formed by the magnet 6, the properties of the ferromagnetic fluid change, in particular, its magnetic permeability increases. This leads to an increase in inductance (therefore, the wave impedance of the delay line) at the location of the magnet 6.

The pulse generator 7 periodically generates probing pulses. In this case, two reflected pulses periodically occur at the input of the level 8 indicator. The first pulse appears as a result of the reflection of the probe pulse in the delay line caused by the magnet, and the second from the end of the delay line. The time interval between these reflected pulses is proportional to the measurement level and is equal to

where f is the distance from the passage of the magnet to the end of the delay line (measured level of medium separation);

V is the propagation velocity of the electromagnetic wave in the delay line;

At is the time interval.

By measuring the time interval At, it is possible to obtain information on the magnitude of the level of media separation.

In the proposed device, the housing is made hermetically sealed from a material resistant to aggressive substances. This allows you to use it to measure the level of separation of media, where the media are chemically active substances. Since the parameters of the delay line are independent of the electrical properties of the measured liquids, these properties do not affect the accuracy characteristics of the device.

The dielectric tube with a ferromagnetic fluid on which the spiral is wound can be rigid or flexible, which makes this design suitable for large measuring ranges, and the use of ferromagnetic fluid and the production of a spiral directly to the generator eliminates the need for piezoelectric elements, as a result of which the construction is simplified.

Claims (1)

DEVICE FOR DETERMINING THE BOUNDARY OF THE MEDIUM SECTION, containing a pulse generator, a level sensor made in the form of a spiral placed in a sealed non-magnetic electrically conductive housing connected to the indicator, and a float with a magnet, characterized in that, in order to expand the measurement range and simplify the design, the winding spiral applied to a dielectric tube filled with ferromagnetic fluid, and connected to a generator. SU <„, 1262291