SU949460A1 - Soil humidity pickup - Google Patents

Description

The invention relates to a measurement technique, namely, to electric express methods for measuring the moisture of soil layers and, mainly, can be used in agriculture at hydro- and ai- meteorological stations and stations, as well as in construction, geology and other Folk households when accurate measurements of the moisture content of amorphous and bulk materials of various densities are needed.

A known sensor for measuring soil moisture, the sensitive elements of which are two isolated electrodes connected to a measuring device l.

However, a known moisture sensor for measuring the moisture of soil layers of various densities is not very suitable due to insufficient sensitivity or mechanical fragility.

The closest in technical essence to the present invention is a capacitive sensor of soil moisture, containing two metal electrodes isolated from each other in the form of screws fixed on

Rod and connected to the measuring device. The electrodes are made in the form of thin-walled screw elements combined and half a step shifted one relative to the other in the longitudinal direction, fixed on a rod of insulating material having a tapered tip.

The screws act as liners.

10 electrical capacitor and serve to immerse the sensor in the ground to the required depth 2.

A significant disadvantage of such a sensor is its low mechanical strength and manufacturing complexity, which significantly reduces the possibilities of using the sensor to measure the moisture content of bulk materials only.

20

When using the sensor in field conditions on dense soils, the augers often fall off of the rod, since the insulation, with which they are attached to the rod, does not withstand 25 multiple loads. The manufacture of screw elements is technologically quite difficult.

The purpose of the invention is to increase the sensitivity and mechanical

Claims (2)

30 strength humidity sensor. The goal is achieved by the fact that in a moisture sensor containing two isolated electrodes attached to a rod and connected to a measuring device, the electrodes are made in the form of two half-screws fastened together by an insulator, forming a screw in general, and one of the half-screws is rigid. connected to the rod, has at the end a guide tooth in the cavity, perpendicular to the direction of immersion of the sensor in the test medium. The drawing shows the proposed humidity sensor, the cut. It consists of a metal half-screw 1, having a guide tooth 2 at the end, which is rigidly attached to the hollow rod 3, electrically connected to it and to one of the connectors of the connector, insulator 4, the second half-screw 5 electrically connected to the other contact connector wire b, passing through the hollow rod 3. Wavelength 10 cm, rod - 90 cm With a circular rotation of the rod, the sensor is immersed to a predetermined depth in accordance with the marks on the rod, then connect the measuring device, and measure. Typically, the moisture content of soil layers on agricultural fields is measured averaged for each layer 10 cm high to a depth of one meter. By extending the rod, the depth of measurement can be increased to 150-300 cm. If necessary, measurements can be made at shorter intervals, for example, after 1 cm. To do this, put appropriate marks on the rod. The averaging value of the measured material can also be changed by increasing or decreasing the height of the sensitive part of the sensor — two half-screws. The main mechanical load is carried by the semi-screw 1, which is connected to the rod having the guide tooth 2, the second semi-screw 5 penetrates the UIC by a trace made by the first screw. It can be glued, for example, with epoxy glue or screwed onto the half-screw 1 with cogs of durable insulating material. The half-screws are made in one-piece monolith by casting in molds or undercuts on a lathe with the last meager separation of the whole screw into two half-screws, which greatly simplifies the manufacturing technology and increases the mechanical strength of the electrical humidity sensor. The use of the proposed electric humidity sensor makes it possible to increase its durability as compared with the known ones by a factor of 10–20, to simplify the manufacturing technology of the sensor. It is possible to use the sensor universally for measuring the moisture content of soils with different mechanical densities and compositions, for example, sands, dense clays, crushed soils. The sensor has a high mechanical strength. DETAILED DESCRIPTION OF THE INVENTION A soil moisture sensor comprising two isolated electrodes attached to a rod and connected to a measuring device, characterized in that, in order to increase its sensitivity and mechanical strength, the electrodes are made in the form of two half-screws fastened together with an insulator to form a whole a screw, one of the half-screws being rigidly connected to the rod and having at the end a guide tooth in a plane perpendicular to the direction of immersion of the sensor in the medium under study. Sources of information taken into account during the examination 1.Berliner M.A. Electrical Measurements, Automatic Control and Regulation of Volatility, M., Energie, 1965, p. 32-52. 2. USSR author's certificate №518707, cl. G 01 N 27/22, 1976 (prototype).