JP2002048742A - Analyzer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive analyzer for estimating contents of two or more kinds of materials. SOLUTION: This analyzer is provided with a single heater, a temperature sensor, and a content estimating device receiving temperature data obtained from the temperature sensor while controlling a temperature change in the heater and estimating a content of a by-product included in a main substance according to analysis on the received temperature data. This analyzer is applicable to a field ranging very widely, and in a soil water content sensor measuring the water content in the soil, for example, when the temperature of the heater 1 is increased, this heat is propagated through the soil so as to increase the temperature of the temperature sensor 2. Because the temperature rise fluctuates according to the water content in the soil, an unknown water content of the soil can be estimated when the temperature rise is compared with a reference data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention is applied to various forms such as powders and granules such as soil, sand, flour, and concrete polymer materials, liquids such as paper and polymer sheets and chemicals, and gels. The present invention relates to an analyzer for estimating the contents of the second and third substances, for example, the contents of water, salt, alcohol, trace amounts of different kinds of powder, etc., contained in the main substance. Since the analysis device according to the present invention can be applied to an extremely wide range of fields, it may be complicated to explain all of the analysis devices in the present patent. Therefore, as a convenient method for simplifying and clearing the description, in the following description, as a typical application example, a soil moisture sensor for measuring moisture contained in soil will be described.

[0002]

2. Description of the Related Art For example, conventional soil moisture sensors include devices based on various principles such as a tensiometer, a ceramic soil moisture meter, a TDR meter (time domain refractometry meter), and are used in the right place for the right material.

[0003] A tensiometer is a moisture sensor in which a ceramic cup filled with water is sealed, and the pressure in the cup is measured. When it is buried in dry soil, the pressure inside the ceramic cup decreases as the water inside penetrates the ceramic wall and is drawn into the outside soil. On the other hand, when buried in soil with a lot of moisture, moisture is pushed from the soil into the ceramic cup, so that the pressure inside the ceramic cup increases. Tensiometer is
This device uses this phenomenon to read the amount of soil moisture as the level of atmospheric pressure in a ceramic cup.

A ceramic soil moisture meter is a device for measuring the electric resistance of a ceramic plate. When this ceramic plate is buried in the soil, the amount of permeated water changes according to the amount of water in the soil. Accordingly, the electric resistance value of the ceramic changes. The ceramic soil moisture meter is a device that uses this phenomenon to measure the amount of soil moisture by converting it into a level of resistance.

[0005] The TDR method is a device that emits an ultra-high frequency radio wave from a small antenna buried in soil, and measures the time it takes to reflect and return from moisture in the soil. This delay time changes with moisture. As described above, the TDR method is an apparatus for measuring the amount of soil moisture by converting the amount of soil moisture into an earlier or later delay time.

[0006]

However, these conventional devices are expensive in all cases, subject to the effects of salts in the soil and ions contained in the fertilizer, during measurement and between the soil and the sensor. Since the exchange of moisture occurs, it is not possible to measure a minute amount of moisture, it is susceptible to ambient temperature, it is necessary to loosen the roots for long-term measurement, and maintenance such as water supply is required There are many problems, for example, that power consumption is large and that it is difficult to drive with a battery or the like.

[0007]

In order to solve such problems, the present invention proposes a moisture sensor which focuses on differences in soil moisture content, specific heat of soil, and thermal conductivity.
Various methods of device configuration based on this basic concept can be considered, and three examples of the configuration will be presented below, and the operation will be described. The first embodiment proposes a device that emits heat from a heating element buried in soil and quantifies the amount of soil moisture from a temporal change in temperature at a point away from the heating element. In the second embodiment, when a board having good thermal conductivity is buried in the soil, a heating element is attached to one end of the board, and a temperature sensor is attached to the other end, and the heating element is heated to transmit heat to the board. Another object of the present invention is to propose an apparatus for quantifying the amount of soil moisture by utilizing a phenomenon in which the amount of heat release differs depending on the amount of moisture in the soil. Further, in the third embodiment, even when the heating element is buried in the soil and a temperature sensor is attached in close contact with the heating element itself, the speed of the temperature rise of the heating element varies depending on the amount of moisture in the soil. The present invention proposes an apparatus for quantifying the amount of soil moisture using a phenomenon.

[0008]

With such a configuration, a moisture sensor that is less susceptible to salts having high electric conductivity, can measure a small amount of moisture by using a simple technique, is inexpensive, and has low power consumption. Can be realized.

[0009]

FIG. 1 shows an example of the constitution of a moisture sensor according to the present invention, wherein 1 is a heating element, 2 is a temperature sensor, 3 is a cover of the heating element, 4 is a window opened in the heating element cover, and 5 is a temperature. This is a data converter that estimates the amount of water by comparing the measured value of the sensor with the standard data. The data conversion device 5 also performs various controls such as turning on / off the power of the heating element, amplifying the temperature measurement signal, displaying and storing the obtained water content, and transferring the data to another computer. Although a control device is assumed, the description below will be limited to the function as a moisture sensor.

When moisture is measured, the heating elements 1, 3, and 4 and the temperature sensor 2 are buried in the soil.
The data conversion device 5 includes a memory, a one-chip microcomputer, a display device, an input / output terminal, and the like. The memory previously stores standard data using soil whose moisture content is known. The one-chip microcomputer has measurement data,
By comparing this standard data, a program that can estimate the current soil moisture content is installed. The estimated water content is stored in a memory or displayed on a display device. Since the data conversion device has such a configuration, it is apparent that a normal computer or a commercially available data collection system can be used instead.

With such a configuration, when the device as shown in FIG. 1 is buried in the soil and the temperature of the heating element 1 is raised, this heat propagates through the soil and the temperature of the temperature sensor is reduced. And eventually settle to a certain temperature. At this time, how the temperature of the temperature sensor rises changes depending on the amount of water in the soil. This is because the specific heat and thermal conductivity of water are different from the specific heat and thermal conductivity of soil. Therefore, by measuring standard data that measures the time lapse of temperature rise from soil whose moisture content is known in advance, and comparing it with data obtained from soil with an unknown moisture content, It will be clear that the quantity can be estimated.

FIG. 2 shows a second configuration example of the moisture sensor according to the present invention, wherein 1 is a heating element, 2 is a temperature sensor, 3 is a cover of the heating element, and 5 is a comparison between the measured value of the temperature sensor and standard data. A data converter for estimating the amount of water by using the heat radiation plate. The heating element 1 is attached to one end of the radiator plate 6, and the temperature sensor 2 is attached to the other end. At the time of moisture measurement, the heating element 1, the temperature sensor 2, the radiator plate 8, and the like are buried in the soil.

With such a configuration, when the temperature of the heating element 1 rises, heat is mainly transmitted to the temperature sensor through the heat sink 6. Heat transfer through the surrounding soil is low. However, the soil around the heat sink draws heat from the heat sink 6. The amount of heat deprived is greatly affected by moisture in the soil. Therefore, the manner in which the temperature rises in the temperature sensor section is greatly affected by the moisture in the soil, as in the first embodiment. Therefore, by comparing measurement data on soil with a known moisture content with data obtained from a soil with an unknown moisture content, the moisture content of an unknown soil can be estimated.

Generally, the greater the area of the radiator plate 6 in contact with the soil, the greater the influence of soil moisture. Therefore,
A longer length gives higher sensitivity. Further, not limited to the plate-like structure, various structures such as a wire-like structure and a radial structure such as a radiation fin can be considered. When a thermocouple is used as the temperature sensor, the metal used for the thermocouple can also serve as the heat sink. In addition, if the structure is wound around the heating element cover 3 to form a spiral structure, the whole structure can be a rod-like structure, which is convenient for embedding in soil.

FIG. 3 shows a third configuration example of the moisture sensor according to the present invention, wherein 1 is a heating element, 2 is a temperature sensor, 3 is a heating element cover, and 5 is a comparison between the measured value of the temperature sensor and standard data. A data converter 7 for estimating the amount of water by using a heat radiating plate, on one end of which a heating element 1 and a temperature sensor 2 are attached. When moisture is measured, the heating element 1, the temperature sensor 2, the radiator plate 7, and the like are buried in the soil. The difference from the second configuration example is that the heat radiation plate protrudes and is buried in the soil, whereas in the case of the third configuration example, the heat radiation plate is wound around the radiator cover 3. That is. Further, as a configuration example similar to this, both the heating element and the temperature sensor are attached to one end of the heat sink, and the other end is only buried in the soil. As an extreme configuration example, the heating element cover 3 may be removed, and the temperature sensor 2 may be directly attached to the heating element 1 without using a heat sink. In this case, the surface of the heating element 1 plays the role of the heat sink 7.

With this configuration, when the temperature of the heating element 1 rises, the heat immediately propagates to the temperature sensor 2. However, the soil around the radiator plate 7 removes heat from the radiator plate 7. The amount of heat deprived is greatly affected by moisture in the soil. Therefore, the manner in which the temperature is increased by the temperature sensor 2 is greatly affected by the moisture of the soil, as in the first embodiment. Therefore, similar to the first and second embodiments,
By comparing measured data on soil with a known moisture content and data obtained from a soil with an unknown moisture content, the moisture content of an unknown soil can be estimated.

In the present embodiment, various shapes can be considered as the structure of the heat sink. Generally, the greater the area of the heat sink in contact with the soil, the greater the effect of soil moisture. Therefore, for example, a structure in which a heat radiating plate spreading radially around the heating element is attached, and the temperature sensor 2 is attached so as to be attached to the heating element can be considered.

FIG. 4 shows a fourth embodiment of the moisture sensor according to the present invention, wherein 1 is a heating element, 2 is a temperature sensor, 3 is a cover of the heating element, and 5 is a comparison between measured values of the temperature sensor and standard data. A data converter 8 for estimating the amount of water by using the second temperature sensor. At the time of moisture measurement, the heating element 1, the temperature sensors 2 and 8, the radiator plate 8, and the like are buried in the soil. The temperature sensor 8 is installed at a distance such that the temperature sensor 8 is not affected by the heat generated from the heating element 1.

With such a configuration, when the temperature of the heating element 1 rises, the heat is measured by the temperature sensor 2, but at the same time, the temperature is also measured by the temperature sensor 8 located far away. In this case, since the temperature observed by the temperature sensor 8 is almost constant, if the difference between the temperatures of the temperature sensors 2 and 8 is calculated, the temperature change due to the heating element being heated is not affected by the ambient temperature. Can be known more accurately. Therefore, by comparing the difference data of the temperature in the soil whose moisture content is known in advance with the difference data of the temperature obtained from the soil whose moisture content is unknown, the moisture content of the unknown soil can be more accurately estimated. You can do it.

If thermocouples are used as these two temperature sensors, as in the case of measurement using a normal thermocouple,
If the reference contact is used as the temperature sensor 8 and the temperature measuring contact is used as the temperature sensor 2, it is possible to directly read the temperature difference. Of course, it is clear that the temperature rise can be estimated by combining two temperature sensors such as thermistors. In this description, the third embodiment is described as an extension of the third embodiment. However, it is apparent that the same contrivance can be applied to the first embodiment and the second embodiment. Further, it is obvious that the temperature sensor 8 does not necessarily have to be embedded at a position separated in the lateral direction as shown in FIG. 4, and may be directly below the heating element. For example, consider a rod-shaped device as a whole, and arrange a heating element 1 and a temperature sensor 2 at one end,
It is conceivable to arrange the temperature sensor 8 at the other end and pierce the soil for use. It will be apparent that by adjusting the length of the rod, a length can be obtained that does not affect the heating element. These are design ideas when the present patented device is designed as a practical device.

FIG. 5 is a diagram schematically showing the time change of the output of the temperature sensor 2, 9 is a diagram showing the time change of the heating element temperature, and 10 is a diagram showing the time change of the temperature of the temperature sensor 2. FIG. 11 is when soil moisture is high 12
Is a schematic diagram of a time change in temperature rise of the temperature sensor 2 when the soil moisture is medium, and 13 is a case where the soil moisture is low. Reference numeral 14 denotes a temperature rise delay region,
5 is a temperature rising region, and 16 is a saturation temperature region. Such standard data is roughly stored in advance in a memory portion of the data converter 5 for obtaining the water content by comparing the measured value of the temperature sensor with the standard data.

When comparing the standard data and the unknown data, it is the best method to compare all the data. However, in this case, the amount of processing performed by the data converter 5 becomes enormous,
Impractical. Therefore, as a simple method, it is conceivable to first compare a temperature sensor temperature at a time t2 in FIG. 5 after a lapse of a certain time from the time t0 when the power of the heating element is turned on. Other methods include the time in the temperature rise delay region 14, the time in the temperature rise region 15, which is the rate at which the temperature rises with time, and the saturation, which is the temperature at which the temperature has settled to a constant value after a long time. It is also possible to perform comparison by focusing on parameters such as the temperature of the temperature region 16.

[0023]

As described above, by adopting such a configuration, various effects are produced as follows. This patent utilizes the thermal properties of substances and does not use the electrical conduction of substances, so even if there are ions generated from, for example, salt or fertilizer, the amount of the Obviously, as long as the amount is smaller than the substance, the estimation of the water content is less affected. This has been confirmed experimentally.

A considerable part of the ambient temperature change can be automatically corrected by incorporating a comparison device with a reference temperature sensor as in the embodiment shown in FIG. . Therefore, it is possible to measure soil moisture stably even when the surrounding temperature environment changes.

Since there is no exchange of water between the sensor and the soil, it is possible to measure an extremely small amount of water. In addition, since the roots of the plant do not cling to each other in search of moisture, there is no root streaking, so that the measurement can be performed accurately. Further, maintenance such as supplying water to the sensor is not required.

Further, according to the present invention, only a small amount of current flows through the heating element at the time of measurement, and a data converter for controlling these can be designed to be turned on only at the time of measurement. Long-term measurement using such a method is also possible.

The main parts of the sensor are a heating element and a thermocouple,
Since it is composed of simple components such as a heat sink, it can be easily realized. If a one-chip microcomputer or the like is used recently, a compact data converter 5 can be realized by simple programming. Therefore, it is possible to obtain an effect that an extremely simple technique and an inexpensive moisture sensor can be realized.

In the above description, description has been made mainly on the premise that soil moisture is measured. However, other powdery substances,
For example, flour, cement, plastic powder,
Obviously, it can be applied to moisture measurement of various powdery substances and sheet-like substances.

Although the above description has been made on the assumption that the amount of water in the soil is measured, even when various materials other than water, for example, fertilizer and sand, are mixed,
It is clear that the amount of the contaminant can be easily estimated if the contaminant and the main substance have significantly different thermal conductivities, specific heats, and the like, and if standard data are obtained in advance. Furthermore, if the application of the device according to the present patent is considered widely, it is also clear that the ratio of the second and third substances having different specific heats and thermal conductivity in one main substance can be estimated. It is also clear that the present invention has features such as low cost and simple device in the application to the field of (1).

[Brief description of the drawings]

FIG. 1 shows a first embodiment of the present invention.

FIG. 2 shows a second embodiment of the present invention.

FIG. 3 shows a third embodiment of the present invention.

FIG. 4 is a fourth embodiment of the present invention.

FIG. 5 is a measurement drawing for estimating water content in soil from the present invention.

[Explanation of symbols]

1 Heating element 2 Temperature sensor 3 Heating element cover 4 Heating element cover Heat release window 5 Data converter for comparing the measured value of the temperature sensor with the standard data to determine the amount of water 6 Heat-radiating plate 7 extending from the heating element cover 7 ·········································································· Heat generation. Time change diagram of current flowing through heating element of body 1 Time change diagram of temperature rise of temperature sensor 2 Time change diagram of temperature rise when water content is small 12 ························································································································· / 14 ····· Temperature rise delay region 15 ······· Temperature rise region 16 ······· Saturation temperature region

Claims (1)

[Claims] 1. A heating element, a temperature sensor, and temperature data obtained from a temperature sensor while controlling a temperature change of the heating element, and analyzing the received data to include a sub-substance contained in a main substance. Analyzer having a device for estimating the amount