CN101769807A - Raindrop hitting power tester - Google Patents

Abstract

The invention relates to a raindrop force tester, which comprises a control box, a computer terminal and a measuring terminal 1. The measuring terminal 1 is composed of a rain cover 10, a support 11, a sensor 20, a base 3 and an amplifier 40; signals from the amplifier 40 are input in sequence into the control box and computer terminal. It can convert the impact force of raindrops into an electrical signal, which is then amplified by the amplifier 40, analyzed and calculated by the computer terminal analysis software, and the calculation results are displayed to directly calibrate and characterize the physical meaning contained in the erosive force of rainfall, so as to reflect the potential of soil erosion caused by rainfall purpose of ability.

Description

A raindrop impact force tester

technical field

The invention relates to an electronic testing instrument, especially related to testing the energy of raindrops hitting the ground surface and characterizing "rainfall erosivity".

Background technique

Rainfall Erosivity is an index used to characterize the contribution of rainfall to soil erosion. It refers to the potential ability of soil erosion caused by rainfall, expressed in R, and the international unit is J mm m ^-2 h. During the rainfall process, the raindrops hit the surface and the confluence scours the topsoil, destroying the surface morphology and soil structure, causing soil particles and nutrients to be washed away with the rain. Rainfall is the direct force that causes soil erosion. Rainfall erosivity is an important erosion dynamics evaluation factor in the universal soil loss equation USLE, the modified universal soil loss equation RUSLE, and the soil erosion and productivity model EPIC. Accurate evaluation and calculation of rainfall erosivity values are essential for soil loss forecasting and soil and water conservation planning. Important links and prerequisites.

The rainfall process is very complicated, and the measurement of rainfall erosivity generally uses mathematical calculation methods, such as standard method and model method.

The standard method is Wischmeier's EI ₃₀ method, also known as the classic method, and the calculation formula is:

R=EI ₃₀ (1)

In the formula, E＝∑e·P, e＝11.897+8.73logi; i is the rainfall intensity (mm h ^-1 ) of a period of rainfall with relatively average rainfall intensity; e indicates the kinetic energy of rainfall per unit rainfall in this period (J m ^-2 mm); P represents the rainfall in this period (mm); E represents the kinetic energy of rainfall (J m ^-2 ); I ₃₀ represents the maximum 30-min rainfall intensity of a rainfall process (mm h ^-1 ).

Since the concept of rainfall erosivity was put forward, the R value has been obtained through the indirect calculation of the algorithm model. The disadvantage is that the calculation process often requires years of self-calculated rainfall observation data, and the data volume and accuracy of rainfall data are very high. , the data collation process is also time-consuming and laborious. If a rough estimation model is used, the validity of the results cannot be guaranteed.

Contents of the invention

The purpose of the present invention is to provide a raindrop impact tester, which can observe the impact force of raindrops in real time during rainfall, so as to directly calibrate and characterize the physical meaning contained in the rainfall erosive force, and achieve the ability to reflect the potential ability of rainfall to cause soil erosion Effect.

The purpose of the present invention is achieved like this: comprising a control box, a computer terminal and a specially arranged measuring end, the measuring end is made up of a rain cover, a support, a sensor, a base and an amplifier; wherein the rain cover is arranged on the support, and The sensor, the base and the amplifier are installed in sequence; the signal of the amplifier is input into the control box and the computer terminal in sequence.

As can be seen from the above, the present invention is divided into three components, measuring end (outdoor part)+control box (indoor part)+computer terminal (indoor part)

The first part: the measurement end, which is the core component of the present invention, is provided with raindrop sensing sensitive components and placed in the field.

The second part: the control box. Provide panel control buttons and digital display functions, placed indoors. The main components are: junction box, display instrument, control panel, etc.

The third part: computer terminal, which provides software and hardware platforms for data display, storage and analysis, and includes connection parts: RS485, RS232 transmission lines, USB extension lines, etc.

During the measurement, the raindrop hits the rain cover, and the sensor converts the raindrop striking force into an electrical signal, which is then amplified by the amplifier and transmitted to the control box and computer terminal, analyzed and calculated by the analysis software, and the calculation result is displayed to achieve the purpose of the present invention.

Description of drawings

Fig. 1 is a composition schematic diagram of the present invention

Fig. 2 is the schematic diagram of the embodiment of the measurement terminal of the present invention

Detailed ways

Referring to Fig. 1, the present invention is made up of three components, measuring end 1, control box 2, computer terminal 3, during measurement, raindrop hits on the rain-bearing cover of measuring end 1, changes raindrop striking force into electric signal through sensor, Then it is amplified by the amplifier and transmitted to the control box 2 and the computer terminal 3. The analysis software analyzes and calculates and displays the calculation results.

Referring to FIG. 2 , the measuring end 1 is composed of a rain cover 10 , a support 11 , a sensor 20 , a base 31 and an amplifier 40 . The sensor 20 is fixed on the base 31 through the spacer 21 , the base 31 is adjusted to the level by the fine adjustment screw 30 , and the levelness of the base 31 is tested by the level bubble 32 . The sensor 20 includes a sensitive element and a structural support, and the sensitive element is attached to the structural support to form the sensor 20 . The sensitive element converts the impact force of the raindrop into an electrical signal, which is amplified by the amplifier 40 and then output.

The raindrop impact force measuring instrument system composed of the above several parts can intermittently measure the impact force F(N) of all raindrops on a unit area at a certain moment of natural rainfall at short intervals, and the sampling frequency is 1-500 times/s , The entire rainfall process has a complete measurement record, which can be conveniently and effectively displayed, stored, and called.

The upper surface panel of the rain cover 10 directly senses and contacts rainfall, does not buffer raindrops, does not consume rain energy, and allows the surface to form a thin layer of water flow similar to the surface. The panel is made of PVC material, and the size can be 50cm*50cm*1cm.

The rain cover 10 hangs vertically along the panel wall with a certain height to form a circle, so that the whole structure forms a windshield design, which prevents the wind from penetrating from below, and forms a disturbing wind field with upward lifting force under the panel, which affects Observations. The size of each side of the windproof side can be 7cm*50cm; the thickness is 3-5mm. Use high-quality PVC materials with smooth surface and light texture (low viscosity coefficient) as far as possible for the windproof edge.

A load cell is installed under the support 11: a measuring range of 0-5 kg, cantilever beam type, independent signal amplifier;

Resistance strain type cantilever beam structure load cell usually uses metal elastic body as the element that converts force into strain. The elastic body (elastic element) produces elastic deformation under the action of external force, so that the resistance strain gauge pasted on its surface is also deformed. After the resistance strain gauge is deformed, its resistance value will change (increase or decrease). The corresponding measurement circuit converts this resistance change into a voltage signal, so that the process of converting external force into an electrical signal is completed through the four conversion links of force, strain, resistance change, and voltage signal change.

The basic parameters of the sensors used in the embodiments of the present invention are as follows:

Model: NSTH-5

Features: Anti-corrosion aluminum alloy material, cantilever beam elastic body;

4-M6 double holes, thread installation is more convenient;

Size: 22mm*30mm*130mm

Capacity: 5kg

Overload: 150%

Power supply: 24VDC

Output: 4～20mA/0～5v (optional)

The base 31 is used to fix the entire device, 48cm*48cm, and the amplifier 40, spacers 21, and horizontal air bubbles 32 are installed and placed on the upper surface. The four corners of the base 31 are installed with 30 legs of fine-tuning screws to ensure that the base 31 is in a horizontal state when the instrument is working.

As can be seen from the above, the present invention can obtain a series of continuous data on the impact force of raindrops in the rainfall process by field real-time observation in the rainfall process, and by analyzing the result data of the rainfall process, dig out its relationship with rainfall rainfall, rain pattern, rainfall erosive force and soil loss. The relationship between F-R is established to achieve the purpose of characterizing and directly observing the R factor and directly evaluating the potential risk of soil erosion.

Under the principle of similarity of rainfall type and characteristics in the same area, using the raindrop impact strength data recorded by this instrument in the long-term test of the whole rainfall process, combined with the current rainfall curve of the rainfall process of the self-recording rain gauge, the extraction of every 10 minutes under the rainfall condition is obtained. The rainfall kinetic energy generated under the rainfall (rainfall intensity) and impact force conditions, and the functional relationship between the 10-min rainfall (rainfall intensity) and rainfall kinetic energy at different gradients were analyzed.

Comprehensively analyze the repeated and verified test results to achieve the calibration of the functional relationship between the two, and use the above-mentioned functional correspondence as a standard to establish a direct relationship from the 10min rainfall to the measured rainfall kinetic energy data. Practice has proved that the present invention can calculate the rainfall erosive force in the past The cumbersome steps of the value are reduced by more than half, which greatly improves the efficiency of obtaining the rainfall erosive force value. If it is necessary to calculate the small-scale rainfall erosive force calculation that requires higher precision, the function can be further calibrated and corrected according to the above method.

The invention can be used as an innovative way to calculate the rainfall erosive force index, has a reliable theoretical basis, enriches the physical meaning of the rainfall erosive force index, and has efficient, accurate and convenient practical functions.

Claims (4)

1. A raindrop impact force tester, comprising a control box (2), a computer terminal (3), is characterized in that the measuring end (1) is specially arranged, and the measuring end (1) is composed of a rain cover (10), a support (11), sensor (20), base (31) and amplifier (40); Wherein the rain cover (10) is arranged on the support (11), and sensor (20), base (31) and amplifier are installed successively (40); the amplifier (40) signal is input in the control box (2) and the computer terminal (3) successively. 2. The raindrop impact tester according to claim 1, characterized in that horizontal air bubbles (32) are set on the base (31). 3. The raindrop impact tester according to claim 1 or 2, characterized in that: the four corners of the base (31) are equipped with finely adjustable screws (30) legs. 4. The raindrop impact tester according to claim 1, characterized in that: the length of the vertical edge of the rain cover (10) covers the base (31).

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