SU447590A1 - Electrokinetic pressure sensor - Google Patents

Description

The invention relates to instruments for measuring pressure in various media.

Known electrokinetic pressure sensors make it possible to measure pressure in air and water. Measuring their pressure in soils leads to large errors, since their perceived elements are in poor contact with the soil material.

The known electrokinetic pressure sensors are made in the form of a sludge, ayush, a vessel with a single cylindrical chamber, placed inside an annular chamber so that when a pressure is applied to the sensing element of one of the chambers (flexible membrane), the liquid flows into another chamber through the porous wall, electrodes which produces an electrical signal proportional to pressure. Since the cameras are directed in the same direction, the effect of the acceleration of the non-flowing does not occur and, therefore, the output signal is not distorted.

However, in measuring, it is necessary to apply pressure to one of the sensing elements, and the other to isolate from pressure, which is practically impossible when installing the sensor in the ground.

The purpose of the invention is to increase the accuracy by measuring the pressure in various media.

For this, the proposed sensor is provided with a reference pressure source, exchanged;

in the middle chamber, with the collector current collecting spectrode of the partitions connected in parallel.

The drawing shows the proposed device.

The device consists of a housing 1, two external chambers 2, flexible membranes 3, porous partitions 4, electrodes 5, an internal chamber 6, a source of reference pressure 7 and a polar working fluid that fills all three chambers.

Flexible membranes, for example, of rubber are made with a thickening in the cylindrical part and at the points of bending. The role of the reference volume (source of reference pressure) is performed by a gas bubble, for example air. It can be enclosed in a flexible sheath, e.g. a rubber sheath, to prevent it from falling onto the erect wall. To do this, it can be strengthened in the center of the inner chamber.

The sensor works as follows.

When it is immersed in any medium under the influence of its static pressure, a part of the liquid flows from the outer chambers into the inner chamber and compresses the on-volume volume, in which the pressure is equalized with the ambient pressure. Membranes, having bent in places of a bend, have elastic contact with the environment. An increase in pressure at the point of sensor installation causes the liquid to flow through the porous partitions from the external chambers to the internal one, and a signal proportional to the pressure appears on the electrodes. When the pressure (vacuum) decreases, the membranes are discharged, and under the influence of the pressure of the reference volume, the liquid begins to flow from the inner chamber to the outer chamber.

A reverse sign appears on the sensor electrodes proportional to the vacuum. In both cases, the liquid flows through the partitions are directed towards each other, and the signals appearing on the electrodes are added.

When the sensor is acted upon by the acceleration, the liquid, the liquid, and with the inertial mass, flows through both partitions into one and the same

the same side, and the electrical signal arising on the wall electrodes is subtracted.

Subject invention

An electrokinetic pressure sensor containing a housing filled with a working polar liquid, the internal cavity of which is divided into three chambers by two porous partitions with collector electrodes, and flexible membranes attached to the ends of the housing, characterized in that, in order to improve the accuracy in measuring pressure in various media, it is provided with a reference pressure source located in the middle chamber, the current collecting electrodes of the partitions being connected in parallel.