SU1376004A1 - Piezometer - Google Patents

Abstract

This invention relates to instrumentation technology. The purpose of the invention is to create a piezometer for measuring the differential compressibility of the working and investigated liquids. A piezometer consists of a measuring chamber in the form of a bellows filled with a working fluid and a test substance associated with a capacitive sensor. Coaxial measuring bellows is an additional bellows, and the cavity between them is filled with working fluid. 1 il.

Description

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The invention relates to devices for determining the change in volumes of substances under pressure and can be used to measure the porosity of substances.

The aim of the invention is to eliminate the influence of the compressibility of the working medium on the readings of the instrument.

The drawing shows schematically the proposed piezometer.

The device consists of a measuring bellows chamber 1 filled with the working medium 2 and the test substance 3, the upper end of which is connected through a flexible membrane 4 fixed in the upper lid 5 to a mercury sensor 6-8 of capacitive type (6 - glass tube, 7 - metal foil, 8 - mercury), the bottom end of the background 1 is covered with the bottom cover 9. An additional bellows 10 is attached to the measuring chamber 1 and coaxially, attached to the top 5 and bottom 9 of the housing cover. The interstitial space 11 formed is filled with working medium 12. In the bottom cover 9 there are openings with ball valves 13 and 14. On the upper cover 5, the housing 15 with windows 16 is screwed on. The bottom cover 9 is tucked into the housing by a spring 17. made of insulating material, inside the high-pressure vessel 19 with the shutter 20-23 (20 —head, 21 — nut, 22.23 — gaskets). The vessel 19 is filled with process fluid 24 introduced through fitting 25. The capacitive sensor leads 26 through an electrical inlet 2 of high pressure connected to a capacitive detector 28 connected to the indicating device 29.

The piezometer is loaded through the opening with valves 13 and 14. First, the test substance 3 and the working medium 2 are loaded into the inner bellows 1 through the channel 14, the valve closes, then the valve 11 fills the cavity 11 through the valve 13, equal to the volume of the working medium in the inner bellows 1. The housing 15 is screwed on the cap 5 until the liquid 12 is shown in the hole, then the valve 13 is closed.

Piezometer works as follows.

Under the action of the pressure P of the process fluid 24, injected into the high pressure vessel 19 transmitted through the mercury column 8 and the flexible membrane 4 into the measuring chamber 1, the working medium 2 inside it is compressed and enters the pores of the test substance 3. At the same time the pressure P, acting through the silo backgrounds 1 and 10, compresses the compensation medium 12, which causes the lower cover 9 to move upwards. Thus, the volume of the measuring chamber 1 is reduced by an amount proportional to the compressibility of the compensation medium 12. With equal volumes and properties of the compensation 12 and working 2 media, the movement of the mercury column 8 is determined only by the pore volume of the test substance 3 and does not depend on the compressibility of the working medium 2. The capacitance of the mercury sensor 6-8 is measured by the capacitive detector 28 and is recorded by the indicating device 29.

As compensation medium 12, working medium 2 can be used.

Using the proposed piezometer by eliminating the compressibility of the working medium when determining the porosity of substances, an accuracy of 0.08% is achieved.

Claims (1)

Formula of Absorption A piezometer containing a measuring chamber placed in a housing, the upper end of which is made in the form of an elastic membrane fixed in the upper crack of the housing, the lower end of the measuring chamber closed by the lower crack of the housing, the internal volume of the measuring chamber filled with working fluid and the test substance, the supramembrane cavity of with a capacitive sensor made in the form of a metal cap glass filled with mercury, the measuring chamber being placed in a high pressure chamber with techno logical fluid, characterized in that, in order to improve the accuracy of measuring the degree of compression of the test substance, the measuring chamber is made in the form of two coaxially arranged bellows, the end parts of which are closed respectively by the upper and lower lids of the case, the cavity between which is filled with a working fluid. 28 23