SU1203385A1 - Strain-measuring device - Google Patents

Description

The invention relates to measuring devices used in experimental soil hydrophysics, agrometeorology, orogenic agriculture.

The purpose of the invention is the use of a tensiometer with a vacuum-liquid manometer in the range of the depths of agricultural crops and the unification of the scale; Tensiometers of all sizes.

The drawing shows the proposed device.

The tensiometer contains a microporous tip 1 and is transparent, with a channel of a cross section, a tubular vacuum liquid manometer 2, hermetically connected to the tip through a plug 3. The channel of the pressure gauge is connected to the bottom of the tip cavity filled with water, and is sealed from above with a plug 4. The channel of the manometer to a certain level is filled with a contrasting working fluid 5, i.e. a measuring volume of 6 air is left in the upper part of the channel. In addition, in the channel, an additional 7 volume of air is added, which is divided into a measured volume by a part of the volume 8 of the working fluid.

The output of the column compensating for its air volume is determined from the ratio

, MIv-7 (n --- g,) 1 -foJPO-Y (H - to)

Cho: .- 5.rF4 | fn

gte {com - length (height) of the compensating air volume, cm, at the pressure RO, hPa;

| - dlipa (height) of the measured volume of air, cm, at pressure PI, hPa;

0

five

0

P | is the minimum value of pressure within the range of measurement, hPa;

7 - density of the working fluid gauge, G / CM; H is the length (height) of the heat gauge or

its size, cm; - length (height) Mepnoi o volume of air, cm, with pressure Рп, hPa; PO is the maximum value of pressure within the limits of the range of pressure (normal - normal pressure) hPa.

The tensiometer works as follows. If the soil pressure is 1: the soil moisture differs from zero (soil) (moisture), then through the pores of the accumulator immersed to the required depth into the soil, the latter sucks some water out of the bottom, resulting in pressure in the device nada, and the measured volume of air in the manometer increases. At the same time, the compensating air volume, which, at the same time, decreases the HEIGHT of the liquid column in the manometer, and thereby stabilizes (compensates) in, increases: the effect of hydrostatic pressure, which, without a compensating volume, would progressively increase as pressure drop in the instrument.

No 1 The amount of the established volumetric volume in the manometer makes it possible to judge the number of canals by the number of cans; 1s (not shown) of the magnitude of cannels about the pressure of soil moisture.

Claims (1)

A tensiometer containing a microporous tip and a vacuum-liquid manometer, characterized in that, in order to use it over the entire range of irrigation depths of agricultural crops and to unify the scales of tensiometers of all sizes, a compensating volume of air is introduced into the channel of the vacuum-liquid manometer, separated from the measured volume of air part of the volume of the working fluid of the pressure gauge. No. o СО СО о о cl