SU754309A1 - Soil moisture-content measuring device - Google Patents

Description

The invention relates to means of moisture measurement and can be used to control soil moisture and its regulation in control devices for land reclamation systems. five

A device for measuring soil moisture is known, comprising a sensitive element enclosed in the upper part filled with water 10

a sealed tube that communicates with a porous vessel and has a metal ring inside, which serves as the core of an inductive transducer coil mounted on 15

the outer surface of the tube and included in the electrical measuring circuit [1}. The position of the metal ring in the tube depends on the water level in it and determines the output signal of the inductive transducer.

The disadvantage of this device is a significant error due to the accumulation of gases in the tube during its operation, which changes the water level in it, the position of the ring and the output signal of the inductive converter at the same soil moisture. . thirty

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Another device for measuring soil moisture is also known, including a porous vessel, communicated by a tube with an air catcher, a sensitive element connected to a transducer of its deformations into an output signal £ .2).

The sensing element of the known device is made in the form of a bellows, mounted on the tube and communicated with it by its cavity.

The disadvantage of this device is that the bellows, having greater sensitivity, make a significant error in the reading due to the effect of changes in atmospheric pressure and hysteresis, reaching 5%.

Measurement errors are also caused by the presence of gases in the bellows cavity, which get together with water in a dissolved state through a porous vessel.

The purpose of the invention is to improve the measurement accuracy is achieved by the fact that the sensing element is designed as a block of aneroid boxes, located in the housing, communicated with a porous vessel and air trap, and the unit is fixed in the building

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754309

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All one end is rigid, and the other is connected with it through an elastic diaphragm connected to the transducer.

The drawing shows the proposed device 'in section.

A device for measuring soil moisture contains a porous vessel 1, a housing 2 with a chamber, a tube 3, a dial-up unit 4 of aneroid boxes, a potentiometric transducer 5 and an air trap 6.

The dial block 4 of the aneroid boxes is located in the housing 2 and is screwed to the base 8 with one end and the other end through the rod 9 is connected by a potentiometer converter 5. The position of the base 8 is adjusted to the thread depending on the amount of aneroid short in block 4. Sealed housing · in place of the exit of the rod 9 from the housing 2 is carried out by an elastic diaphragm 10-, clamped by the inner part on the rod 9, by the nut 11 and the outer part in the housing 2 by the sleeve 12 having a console for fixing the potentiometric converter 5. The housing communicates through the opening 13 with the cavity of the vessel 1, which is attached to the housing with a rubber sleeve 14 and nut 15, and through a metal tube 3 with an air trap 6. The axes of the vessel 1 and the pipes 3 are in line and perpendicular to the axis of the block 4 aneroid boxes. The air trap for the purpose of detecting air in it is made of a transparent material and has an opening that is closed by a stopper 16 for filling the hermetically sealed system of the device with water and for removing air from it.

The length of the tube 3 is determined by the depth of installation of the device for measuring moisture in the soil.

Potentiometric transducer 5 is protected from the environment by a cap 17 having a channel 18 for inputting current-carrying wires. All parts are made of anti-corrosion materials and their joints are sealed.

The device works as follows.

Collected and filled with water, it is placed in the soil at the required depth at the bottom of the well and remains there during the operation of the measuring system. Moisture exchange with the soil is carried out through the porous bottom of the vessel 1. When the soil dries out, some of the water from the hermetic system of the device is sucked in by the soil until the vacuum in it balances the sucking power of the soil. 1 penetrates into the hermetic system of the device, changing the vacuum in it. Unit 4 aneroid boxes, attached at one end to a fixed base 8, under the action of the created pressure drop in the sealed

^e device system and in sealed

cavities of aneroid boxes is deformed, and the linear movement of the movable end of it through the rod 9

(O is transmitted to the engine of the potentiometric transducer 5. The voltage removed from it is functionally dependent on the sucking power of the soil or its moisture.

During operation of the device, the removal of accumulated air from its hermetic system is performed by topping up water through an opening in the air trap 6, which is closed

_c stopper 16.

Measurement of soil moisture by this device by means of an electrical quantity allows it to be used in remote automated control and regulation systems.

25 soil moisture. Improving the accuracy of measurements makes it possible to more effectively control and control soil moisture, as a result of which the yield of agricultural crops can be increased by 15–20%.

Based on this increase in yield, the annual economic effect of moisture control using data

35 devices in the operation of the irrigation system on the basis of two sprinkling machines "Frigate" can be 5-7 thousand rubles.

Claims (1)

Claim A device for measuring the moisture of a soil, including a porous vessel, communicated by a tube with an air catcher, and a sensitive element connected in a transducer of its deformation into an output signal, differing in that, in order to improve the measurement accuracy, 50, the sensing element is designed as an aneroid box unit in a housing in communication with a porous vessel and air trap, the unit being rigidly fixed in the housing with one end and the other ~ connected to it through an elastic diaphragm connected to the converter.