SU556338A1 - Pneumatic level gauge bulk materials - Google Patents

Description

one

The invention relates to a technique for measuring the level of bulk materials and may find application in measuring the level of coal dust in industrial bunkers of thermal power plants.

A pneumatic level gauge of bulk materials is known, the principle of action of which is based on a change in the flow rate of air flowed through a tube, perforated but its length with calibrated holes, surrounded by an elastic sheath and lowered into a container. When the level of the bulk material changes due to the thinning of the elastic shell to the walls of the tube, part of the calibrated orifices closes, the tube changes its conductivity, and consequently, the air pressure in it, judging by its magnitude.

However, such a level gauge has a low measurement accuracy due to pressure fluctuations in the supply air and low sensitivity due to the need to measure small increments of the output pressure at a relatively large absolute value.

These drawbacks are partially eliminated in the pneumatic level gauge of bulk materials containing a source of stabilized pressure, an elastic shell, a rigid hermetic partition, equipped with

divided by the same partition into two parts with a tube with holes evenly distributed over its entire length, throttles and differential manometer.

The disadvantage of this level gauge is the discreteness of the measurement, as well as possible during operation changes of the cross section or complete clogging of individual holes as a result of clogging, corrosion effects, etc., which decreases the sensitivity and accuracy of the measurement.

Of the known level gauges, the closest but technical essence and achievable

The effect of the invention is a non-pneumatic level gauge containing a stabilized power source, a primary transducer made in the form of a board with an open longitudinal throttling channel,

covered by an elastic membrane, hermetically fixed around the perimeter of the board and the secondary device.

Claims (1)

However, this level gauge has an insensitive sensitivity due to the design of the primary transducer with one longitudinal throttling channel, which does not allow accurate recording of small increments in output pressure with a relatively large absolute value. The aim of the invention is to increase the sensitivity and accuracy of measurement. This is achieved by the fact that the primary converter board is additionally equipped with a second open longitudinal throttling channel located on its opposite side, as well as two closed longitudinal channels connecting the first and second open throttling channels respectively with a source of stabilized power. FIG. 1-3 a schematic diagram of the device with cuts is shown. The pneumatic level gauge contains a stabilized power supply 1, a primary converter 2, which includes a board 3, equipped with 4 open throttling channels connected in pairs and closed 5, an elastic membrane 6, an input choke 7, an output choke 8 and a differential pressure meter 9. The pneumatic level gauge works as follows. Compressed air from the source of stabilized power supply 1, forks on one side through throttle 7, right channel 5 and a TJ junction cavity formed by plate 3 and membrane membrane 6 to the atmosphere, on the other hand through left channel 5, corresponding to the left cavity and choke 8 into the atmosphere. In the absence of bulk material in the container, the elastic membrane 6 of both cavities under the action of air pressure moves away from the board 3 along its entire length. In this case, the pneumatic resistance of the cavities will be minimal. In this case, due to the selection of chokes 7 and 8, the pneumatic resistance of the duct sections before and after the connecting points of the differential pressure gauge is insignificant and the same, and the pressure at the connection points of the differential pressure gauge 9 is not the same - the differential pressure on the differential pressure gauge is maximum. As the container fills the bulk material, the elastic membrane 6 is pressed against the plate 3 by the action of the lateral pressure of the measured medium, as a result of which the flow area in the area where this pressure occurs decreases, and its minimum value is determined by the cross-sectional area of the throttling channels 4. In this case, the pneumatic resistance of these sections of the duct varies in proportion to the level of the medium being measured. Accordingly, the pneumatic resistance will vary the pressure in the inter-throttle portions of the air ducts. The pressure drop recorded by the differential pressure meter 9 at each time point corresponds to the degree of filling of the tank. Claims Pneumatic level gauge bulk materials containing stabilized power source, primary converter, made in the form of a board with an open longitudinal throttling channel, covered by an elastic membrane, hermetically fixed along the perimeter of the board, and a secondary device, characterized in that, in order to increase sensitivity and accuracy measurement, the primary converter board is additionally equipped with a second open longitudinal throttling channel located with its opposite side. and two closed longitudinal channels connecting, respectively, the first and second open throttling channels with a source of stabilized power. / 1-4 2 55 FIG. 3 FIG. /