SU1441309A1 - Multiple-point extensometer - Google Patents

Abstract

The invention relates to the field of measurement technology, in particular, to devices for measuring the potential of soil moisture. The aim of the invention is to improve measurement accuracy and enhance functionality. The multipoint tensiometer (MT) consists of body 1, microporous sensors 15, connecting hoses, air coolers 16 with elastic cuffs 17 mounted on them, gauge tubes 2 and gauge tank. Increase accuracy

Description

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measurement is achieved by maintaining the fluidity of system W at. removing air and a valley of water into air catchers 16. To improve performance and enhance functionality, case 1, body cover and support stand are made of duralumin box section section, the connection points, gauges 15 with pressure gauges are compact, and the pressure gauge has a cover 7 with a hole 8 closed by a gas-permeable stopper 9. 1 h, p. f-ly, 5 ill.

The invention relates to a measurement technique, namely, devices for measuring the potential of soil moisture, and can be used in closed and open field agriculture, land reclamation and ecology.

The purpose of the invention is to increase the accuracy of the measurement and enhancement of functionality.

FIG. 1 shows a multipoint tensiometer, a general view; on a multipoint tensiometer installed for operation, vi, d to the left; FIG. 3. - section A-A in FIG. 2; in fig. 4 shows the sensor of the tensiometer j in FIG. 5 - the tensiometer in the assembly;

The multipoint tensiometer consists of a body made of dures aluminum box section, in which there are two gauge tubes 2 made of glass. For field conditions, housing 1 is fixed to support leg 3, which is located in the soil. At the front and on top of the housing 1 is covered with a claw 4; In the lower part of the housing 1 there is a transparent container 5, intended for a manometric liquid, which is fixed in the movable carriage 6, the container 5 is provided with a cap 7, which has three openings, one of which is connecting 8, to create atmospheric pressure in the bone 5. This opening is closed by a gas permeable fabric plug 9, which protects the gauge fluid from contamination. The other two openings (inlet openings 10) are intended for inserting the lower ends of the manometric tubes 2 into the manometric container 5, the Manometric tubes 2 are located ..

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on the plastic gasket 1I, fixed inside the housing 1. The gasket 11 does not reach the lower edge of the housing 1 and forms a step in which the pressure gauge 5 enters in the working position of the tensiometer. Each manometric tube 2 has a measuring bar 12, mounted on a plastic gasket 11, made, for example, of a standard measuring tape tape measure. The upper ends of the manometer tubes 2 are connected to plastic tees 13. The lateral outlets of the tees 13 are connected to the connecting hoses 14, the upper ends to the air trap 16. The cuffs 17 made of a vacuum hose are mounted on the air coolers 1, with an inner the diameter of the latter is such that the fitting of the syringe is securely sealed in the cuff 17. At the bottom of the cuffs

, e 17 there are screw clamps 18, the width of the compression planes of which is equal to the inner diameter of the cuff 17, the connecting hoses 14 are connected to the upper ends of the cone-shaped tubes 20, which are made, for example, from a single-use needle syringe cap. The cone-shaped tubes 20 are secured by rubber seals 21 in the upper ends of the extension tubes 19, which

35 are made, for example, of transparent hard plastic. The sensors I5 and the extension tubes 19 are connected by pieces of polyethylene tube 22, while the internal diameter of the latter is less than the external diameter of the flexible tubes 19 and the upper parts of the sensors 5, In the transport cable 1 x1: 1, body I

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the pressure gauge, support leg 3 and body cover 4 are packaged, they are vertically one above the other and connected with a portable belt 23. To protect the ends of the gauge tubes 2 during transport, an additional key 24 is installed between the body cover 4 and the body 1,

Multipoint tensiometer works as follows.

The sensor 15 tensiometer installed in the soil at a predetermined depth vertically or at an angle of 70-80 °. As a result of the equalization of the moisture potential between the soil and the microporous sensor 15, the water from the sensor 15 begins to flow into the soil, so water tension is created in the cavity of the microporous sensor 15. The resulting tension from the cavity of the sensor 15 connected via a polyethylene tube 22 to the extension tube 19 is transferred through the water of the tensiometer system to the pressure gauge. At the same time, the manometric liquid from the tank 5 rises into the manometric tube 2 mounted on a plastic gasket 11 located inside the housing 1. The lifting height of the manometric liquid is fixed on a measuring scale 12 that corresponds to a certain potential of moisture in the soil. During the operation of the tensiometer, a constant Moisture exchange between sensor 15 and soil. As a result, soil moisture with gases dissolved in it enters the tensiometer system, where the dissolved gases, under the influence of water tension and temperature fluctuations, appear in the form of air bubbles. Lead air passes from sensors 15 and extension tubes 19 into cone-shaped tubes 20 fixed in the latter with the help of seals 21, then into the connecting hoses 14. Of the latter, air gets into the tees 13, and then into the air catchers 16. Removal of the accumulated air from the air catchers 16 without depressurization of the tensiometer system. For this purpose, the standard syringe fitting is sealed in the cuff 17. The syringe is pre-filled with water in an amount corresponding to twice the volume of the air balloon.

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The gateway 16 is then opened by 18; as a result, the internal volume of the syringe is connected to the tensiometer system without disturbing the latter. From the air catching bodies 16, the air is transferred to the internal volume of the syringe with the help of flowing reciprocating movements of the syringe piston with a piston stroke of 0.5-1.0 cm. As a result, an equal amount of air flows into the air trap 16 water from a syringe. After the piston has been removed by a return stroke, the column of gauge fluid in tube 2 is set at the mark on the gauge scale 12, at a small amount that exceeds the tension of the water in the tensiometer before it was removed. This value is determined in advance. It is equal to the decrease in water tension in the tensiometer, which occurs when the latter is sealed with a screw clamp 18. After this, seal the cuff 17 with a screw clamp 18 and remove the syringe fitting from the cuff 17,

To bring the tensiometer in the transport position sa take off. The housing is disconnected from the support post 3, which is removed from the soil, the I 5 sensors are removed from the soil, then the water in the tensiometer is discharged by fully immersing the sensors 15 in a vessel with water. Then, the carriage 6 is disconnected with a manometer 5 and hermetically closed the ends of the manometric pipes 2, for example, with plugs made of pieces of connecting hoses 14, tightly closed on one side. After that, an additional kryshka 24 is installed over the ends of the tubes 2, the gas-permeable fabric stopper 9 is removed from the connecting hole 8 of the key 7 of the manometric tank, then the connecting plug is closed with plugs

0 hole 8 and outlets 10. From the extension pipes 19, the rubber seals 21 and the cone-shaped tubes 20 fixed in them are taken out.

5 full 20 tubes closed with traffic jams. The connecting hoses 14 are placed inside the housing 1 tensiometer. The sensors 15 hermetically sealed with plastic bags and together with at 14

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Claims (2)

Claim 1. A multi-point tensiometer, including 15 microporous sensors, liquid manometers, connecting hoses, and air traps located in the housing, distinguishing distinctive hoses of microporous sensors are made in the form of conical flexible transparent tubes. 2. The tensiometer in π. 1, wherein the transparent container for the gauge liquid is provided with a lid with an opening in that, in order to increase the accuracy of measurement and expand the functionality, it is equipped with a transparent container for the gauge liquid, a movable carriage 20 mi and a gas-permeable porous tube, moreover, a gas-permeable porous tube is installed in one hole, and the other holes are connected to manometric tubes. ayug.g L- 4 <Fie. 3