SU559124A1 - Pneumatic level - Google Patents

Description

one

The invention is VULNERATED to the technique and the level of bulk materials, and can be used as a sensor in automated control systems.

Devices for measuring the level of bulk materials are known, the principle of action of which is based on a change in foam resistance by throttling the holes along the path of the passage of the lithium air by an elastic membrane under the influence of the measured medium 1.

The disadvantage of this sensor is low sensitivity and high measurement resolution.

Also known is a level gauge containing a primary transducer with a 1-meter tight membrane attached to it around the perimeter, covering the throttling channel, the air inlet and outlet nipples and the secondary device L.2. . The primary transducer is a strip with a longitudinal throttling channel on its surface.

The disadvantage of such a device is the low sensitivity of the device, since a significant increment of pneumatic resistance corresponds to a significant increase in the level.

The purpose of the invention is to increase the sensitivity of the gauge.

The goal is achieved by the fact that, in a well-known pneumatic level gage, the primary transducer, which is hermetically covered over the entire height by an elastic membrane, is made in a vice hollow cylinder, with a throttling channel screw-shaped on its outer surface.

The drawing shows a schematic diagram of the proposed level gauge.

Claims (2)

The level gauge has a primary transducer 2 located in the bunker 1 with bulk material, connected by means of pneumatic lines 3 to a measuring circuit with a secondary device 4 fed by compressed air of constant pressure. The primary transducer 2 contains a hollow cylinder 5 with ripoc-Seli-rukhim 6 and a hole 7, which is screw-shaped on its outer surface and communicates postotions with the cylinder cavity p. The valve in the lower part 5 is closed with a plug 8 into an elastic sheath (membrane) 9, sealed with a cover Yu, which is fitted with an air inlet fitting 11 and an air outlet fitting 1. Pneumatic gauge works in the following way. At zero level in the bunker 1 of the elastic shell 9 of the primary converter 2, only the static pressure of the air passing through it acts, as a result of which the shell 9 has a lowering at which the flow cross section is greatest and which depends on the elastic properties of the shell and the pressure entering through the hole 7 of air. In this case, the pneumatic resistance of the primary converter 2 is minimal. As the bunker 1 is filled with loose material, the lateral pressure of the medium being measured acts on the elastic shell 9, as a result of which the flow section in the area where this pressure occurs is reduced, and its minimum value is determined by the cross-sectional area of the throttling channel 6, and design parameters (cylinder diameter and helix pitch). Thus, when the level changes, the wedge of the throttling section of the channel changes, i.e. the length of the section of the primary presenter with the minimum cross-sectional area, which leads to a change in its conductivity in proportion to the level value. Pneumatic resistance measurements can be made using any of the known methods (including a primary converter into a pressure divider circuit or a pneumatic bridge circuit). A new form of the throttling channel g is a form of a groove screwed on the outer surface of the cylinder, which increases the sensitivity of the primary converter compared to in l / siTi d. times, since for a known level gauge the change in the length of the throttling section of the channel (thereby changing the conductivity of the primary converter) when the level changes in the bunker ° is de.di, and for the proposed level gauge. & H where H is the level increment; uL | ul-ij is the corresponding H increment of the length of the throttled channel section, respectively for the known and proposed level gauges; o (. is the angle between the tangent to the helix and the cross-sectional plane of the cylinder. The device can be used in the energy, coal, metallurgical, mining and food industries, especially in explosive and fire hazardous conditions. Invention formula Pneumatic level gauge containing primary a transducer with a sealed membrane attached to it around the perimeter, covering the throttling channel, the air inlet and outlet nipples, the secondary device, characterized in that, in order to increase the sensitivity STI, the primary transducer, hermetically covered over the entire height by an elastic membrane, is made in the form of a hollow cylinder with a helical throttling channel on its outer surface. Information sources taken into account during the examination; 1. USSR author's certificate No. 456985, M. Kl. Q 01 F 23 / 16,1973. 2. USSR author's certificate G 01 F 23/16, J 973 No. 484406, M. Cl. (prototype). Aa eight