JP2000028513A - Simple measuring device for air permeability of soil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simple measuring device for diagnosing air permeability of soil. SOLUTION: Air permeability of soil is diagnosed by measuring the injection speed of air at injection of compressed air into the soil. For this diagnosis, members such as a storage container 4 of compressed air, an air flow regulating valve 30 to adjust an air flow rate discharged from the container 4, an air flowmeter 6 to measure the amount of discharged air, and an air injection tube 11 to inject the discharged air into the soil are connected to each other through narrow flexible air transportation tubes 5 to be used. When the measurement with high accuracy is required, an air pressure regulating valve 40 for adjusting the outflow pressure of the compressed air discharged from the storage container 4 is used together.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a simple measuring apparatus for air permeability, which is one item of physical property diagnosis of soil in the fields of horticulture and agriculture.

[0002]

2. Description of the Related Art In the field of horticulture and agriculture, good quality soil is required for healthy plant growth. Physical properties such as drainage, water retention, air permeability, and fertilizer retention are required as good quality soil. You. Drainage and drainage are measures of whether the water required for plant life is adequately supplied to the roots, and breathability is the supply of oxygen required for respiration performed by the roots to absorb nutrients It is a measure to know whether or not.

[0003] These physical properties are all related to the amount of large and small voids present in the soil (hereinafter referred to as the amount of coarse pores). The coarse pore volume is the sum of the liquid phase occupied by moisture and the gas phase occupied by air, carbon dioxide, or the like, and a liquid or gas exists in the pores. When it rains, most of the coarse pore volume is occupied by the liquid phase, which makes it difficult for air to pass through and deteriorates air permeability. When the rain stops, the water gradually sinks, and the gas phase increases instead of the liquid phase, and the air permeability improves.

The greater the amount of the coarse pores, the better the drainage and air permeability, and the smaller the amount of the coarse pores, the worse the drainage and air permeability. Therefore, an appropriate amount of coarse pores is required for plant growth. That is, when the amount of coarse pores in the whole soil is about 30% or more, drainage and air permeability are too good to easily dry, and almost 10%.
% Or less, it is said that the water content tends to be excessive and the air permeability is insufficient, and the growth of the plant is poor in any case.

[0005] Drainage and air permeability of horticultural soil and fields are adjusted by blending various medium materials of plant and mineral substances whose water permeability and porosity (air permeability) are known in advance. However, the medium material actually applied to the land has a complicated structure due to external factors such as cultivation, traffic of cars, vibration such as earthquakes, or penetration of rainwater, and in many cases, the properties do not always match the original materials .

Actual drainage of land is usually determined by observing the wetness of the ground surface. Also, it can be easily measured by an electric moisture meter. On the other hand, since there is no easy way to check the air permeability, it is only possible to indirectly estimate the air permeability by draining or drying. But,
This is a qualitative judgment to the extent of getting tired, and a quantitative evaluation of the specific degree of air permeability has not been made much.

[0007] To quantitatively determine the actual air permeability of land, (1) measurement of the water content and the gas phase content by a tensiometer,
There are methods such as (2) measurement of oxygen diffusion rate using a platinum electrode and calomel electrode, and (3) composition analysis of soil air (soil science, agricultural civil engineering handbook, etc.). However, these methods determine the air permeability from the behavior of the gas, and do not directly measure the air permeability itself. In any case, it is difficult to easily carry out these methods that require equipment and technology in a site such as a garden or a field. In addition, although the measurement of the ventilation velocity by a ventilation meter is partially introduced, the details are unknown.

[0008]

As described above, despite the fact that the permeability of soil is known to greatly affect the growth of plants, there is no easy method for examining the wetness and dryness. Alternatively, it has been appropriately estimated based on soil properties and the like, and in many cases, the actual state is unknown. For this reason, even if the air permeability becomes inappropriate and the growth of the plant is hindered and withering, the cause cannot be understood at all and no action can be taken. At present, it is not known how much it is even if it is intended to improve the air permeability.

Although there are various causes of plant withering, it is desirable to constantly examine the actual condition of at least air permeability, which is an important factor, and if there is a problem, to improve it promptly to maintain the living environment of the plant better. . In view of such a situation, an object of the present invention is to provide a simple measuring device for easily diagnosing the permeability of soil.

[0010]

SUMMARY OF THE INVENTION The present invention is to inject air into soil and to diagnose the permeability of the soil based on the rate of air injection. As a means for that,
A member such as a compressed air storage container, an air flow control valve, an air flow meter, and an air injection pipe is connected and used by a flexible thin air transport pipe. When performing more accurate measurement, an air pressure adjusting valve is also used.

The compressed air storage container is for temporarily storing air to be injected into the soil, and is provided with a general cock and / or valve at each of the air inlet and outlet. Various materials can be used as long as they are airtight, but rubber is preferable from a practical viewpoint. As the size is larger, more air is used for measurement, and the measurement accuracy can be improved. However, if the size is too large, handling becomes inconvenient, so the size is determined by a balance between the two.

[0012] The compressed air used in the measuring device flows into the storage container from a separately provided pump. As the pump, a general-purpose portable pump such as a manual pump or a stepping pump is generally used. Especially when performing highly accurate measurement, it is used by connecting to a device such as a compressor that can continuously discharge air at a constant pressure.

[0013] The air flow control valve is used to simplify the measurement.
This valve is used to determine in advance the opening / closing degree of a valve that outputs a reference amount of air. That is, in this measuring device, various measured values are output according to the amount of coarse pores in the soil, but it is better to determine a reference value in advance in order to evaluate the level of the measured values. It is convenient. As the reference value, the amount when the compressed air is discharged into the air, in other words, the flow rate when the coarse pore amount of the soil is assumed to be 100% is used. Specifically, when the compressed air is discharged into the air, the float of the flow meter is set to reach the upper limit of the scale, and the degree of opening and closing of the valve is fixed. By doing so, it is possible to immediately determine the ratio of the ventilation amount to the coarse pore amount of 100%.

However, when actually measuring the amount of air permeated through the soil, it is troublesome to adjust the outflow amount of air to a predetermined amount only with a general cock or valve provided on the outflow side of the storage container for compressed air. And the stored air may be lost during adjustment. Therefore, it is necessary to provide another valve that can immediately output a predetermined amount of air at the same time as starting the measurement. On the other hand, since the amount of air passing through the measuring device is very small, the degree of opening and closing of the valve must be finely adjusted in order to improve the accuracy. Naturally, it is necessary to clarify the outflow conditions, and the valves used here can be used to determine the opening and closing degree, and at the same time, fix the opening and closing degree of the valve so that the opening and closing degree of the valve does not change during measurement It is desirable to have a device.

The air pressure regulating valve is a valve provided for minimizing the fluctuation range of the air pressure and improving the accuracy of measurement. This measurement device is for comparing and diagnosing air permeability at an arbitrary position in soil, and air must be injected under as constant conditions as possible. However, as described above, the measurement apparatus is based on the principle that the air permeability in the soil is examined using the compressed air temporarily stored in the compressed air storage container. Therefore, if air flows out of the storage container, the pressure in the container gradually decreases, causing a measurement error. In order to reduce this error, it is desirable to reduce the pressure change of the air as much as possible before injecting the air into the soil.

An air flow meter measures the amount of air injected into the soil. The present inventor studied the applicability of various flow meters such as a squeeze flow meter, a volume flow meter, and an area flow meter as an air flow meter used in the present invention. As a result, any flow meter can be used. It has been found that the meter has the simplest structure, is easy to miniaturize, and is suitable for the purpose of the present invention. The area flowmeter can measure the flow rate by moving the float even if the air volume is about several milliliters per second if the float is lightened and the throttle area is reduced. In the case of this measuring device, since the amount of air passing through the soil is very small, measurement for several minutes can be performed if there is an air amount of several tens of liters. Therefore, even with the temporarily stored air amount, a simple comparative test can sufficiently measure. In addition, as a material of the float, a lightweight resin or a foamed resin is suitable.

When the above-mentioned area flow meter is used, it can be directly connected to an air flow control valve or the like, but if it is used as it is, the meter is easily damaged and is difficult to handle. Therefore, if the instrument is protected by storing it in a transparent container that is easy to see from the outside, such concerns will be eliminated and it will be easier to use. As the transparent container, various pipe structures such as plastic, glass, cylindrical, polygonal cylindrical, truncated cone, and truncated polygonal cones can be used. Among these, a cylindrical material made of plastic is preferable from a practical viewpoint.

The air injection tube is inserted into the soil to inject air for measurement. For this reason, it is necessary to have a strength that does not cause abnormal deformation when inserted into the soil. On the other hand, since the air injection pipe is often inserted near the root of a plant planted in soil, it is preferable that the air injection pipe be thin in order not to damage the root. On the other hand, if the air injection pipe is clogged by soil, measurement becomes impossible,
Particular care must be taken to prevent blinding. As a method of preventing clogging, the inventor has studied various means such as turning the vent sideways, covering with a mesh, or using a porous material, but a method of opening and closing the vent with a valve is known. It has been found to be simple and effective.

In the configuration of the present measuring device, various members such as an air pressure regulating valve, an air flow regulating valve, and an air flow meter are provided between the compressed air storage container and the air injection tube, such as a vinyl tube, a rubber tube, and a silicone rubber. They are connected by a flexible thin air transport pipe such as a pipe, but the order of connection is not particularly limited. If the storage container for compressed air and the air injection pipe are arranged at both ends, the operation is almost the same regardless of the order in which they are connected, so that they can be used in an easy-to-use order. Further, it is not always necessary to connect all the members with a flexible thin tube. When the apparatus is reduced in size, it can be partially connected with a rigid tube or used integrally.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIG. Since the present invention employs the above-described means, when implementing this, first, the compressed air storage container 4, the air flow control valve 30, the air flow meter 6, the air injection pipe 11, etc. are made flexible and thin. They are connected by a pneumatic transport pipe 5. To perform more accurate measurement, the air pressure adjusting valve 40 is incorporated.
Next, air is press-fitted into the compressed air storage container 4 using a separately provided pump (not shown). Then air flow meter 6
The cock 3 on the outflow side of the compressed air storage container 4 and the air flow control valve 30 are opened with the air vertically opened, and the air vent 19 of the air injection pipe 11 is fully opened according to the operation described later to release air into the air. I do. Then, while adjusting the opening / closing degree of the air flow control valve 30, the float 9 of the air flow meter 6 comes to the uppermost scale of the area flow meter 8, and the opening / closing degree of the air flow control valve 30 is fixed there. I do. This opening / closing degree is used as a reference as the opening / closing degree corresponding to the amount of air when the coarse porosity is 100%.

When the opening / closing degree of the reference air flow control valve 30 is determined, the opening / closing degree is fixed there, and the cock 3 on the outlet side of the compressed air storage container 4 is closed once to stop the flow of air. In this state, the air injection pipe 11 is inserted into a predetermined position in the soil, the slit 18 of the rotary valve 17 of the air injection pipe 11 is aligned with the ventilation port 19, and the cock 3 is opened again. The air volume is injected into the soil. By reading the injection speed at this time from the air flow meter 6, a ventilation amount corresponding to the coarse pore amount of 100% is obtained.
If the rise of the float 9 is slow at the start of the measurement, the measurement can be performed under the same conditions as in the adjustment by opening the air flow regulating valve 30 once, allowing the float 9 to rise, and then returning to the original opening / closing degree.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited thereto. FIG. 1 is a schematic configuration diagram showing the whole of the present invention, FIG. 2 is a schematic sectional view of an air flow regulating valve, FIG. 3 is a schematic sectional view of an air pressure regulating valve, and FIG. 4 is a schematic sectional view of an air injection pipe.

As shown in FIG. 1, the measuring apparatus according to the present invention has cocks (2, 3) at the air inlet and the air outlet, respectively.
Is connected in series to the air pressure regulating valve 40, the air flow regulating valve 30, the air flow meter 6, and the air injection pipe 11 by a flexible thin air transport pipe 5. It is constituted by being done. Here, the compressed air storage container 4 is made of rubber, and the cocks (2, 3) are general cocks having only an opening and closing function. The air flow meter 6 is provided inside a transparent plastic cylindrical container 7.
A plastic area flow meter 8 is also housed therein, and the float 9 is made of a foamed polystyrene resin. The material of the flexible thin air transport pipe 5 for connection is silicone rubber.

The air flow regulating valve 30 shown in FIG. 2 is a needle valve which can be finely adjusted. The valve opening / closing degree can be fixed to a valve rod 35 for adjusting the opening / closing degree of a valve element 36. A plate 34 is mounted. Further, a valve opening / closing indicator plate 33 is fixed on the upper part so that the opening / closing degree of the valve can be recognized. The material of the needle valve is not particularly limited to metal, and may be a valve mainly composed of plastic.

The air pressure regulating valve 40 shown in FIG. 3 is composed of three valves. Here, the valve 40a is a first valve, and the valve body 47 is held down by the valve seat 46 by the valve adjustment spring 48, and only air having a certain pressure or more can be passed by the force of the valve adjustment spring 48. It has become. Valve 40b
Is a second valve to which an area flowmeter is applied, and the float becomes a valve body 52 and is supported from below by a valve adjusting spring 53 having a weak force. If air enters here from above, if the force of the spring is smaller than the pressure of the air, the valve body is pushed down, the air passage is closed, and air cannot pass. If the air pressure inside the valve 40 decreases and the spring force is greater than the air pressure,
The valve body is pushed up and air passes. For this reason, when the pressure of the air is high against the force of the spring, the air does not pass, and when the pressure is low, the air passes. The valve 40c is a third valve having the same structure as the valve 40a, and is used so that the flow rate of air is smaller than that of the valve 40a by reducing the air passage or adjusting the force of the spring.

When air is passed through the air pressure regulating valve 40 having the above structure, air having a certain pressure or higher passes through the valve 40a and the valve 40a.
b and the valve 40c. At this time, if the pressure is greater than the force of the valve adjusting spring 53 of the valve 40b, air does not pass through the valve 40b, and a smaller amount of air passes through only the valve 40c than in the valve 40a. When the pressure inside the valve 40 decreases, the valve 40b
Is opened, and air flows from both the valve 40b and the valve 40c. In this way, compared to the case where only the valve 40a is used, a region where the decrease gradient of the outflow air amount at the air outlet 55 becomes gentler is formed, and the measurement error can be reduced.

The main body 16 of the air injection pipe 11 shown in FIG. 4 is a thin metal pipe having an appropriate strength, and a small ventilation port 19 is provided in the vicinity of the tip thereof. A rotary valve 17 having a slit 18 for passing air is provided at a position inside the air injection tube corresponding to the vent.
The rotary valve 17 is supported at its upper part by a valve stem 15, and can be rotated left and right by operating a valve rotary button 12 at the upper end connected thereto.

When the air injection pipe 11 is inserted into the soil, the ventilation port 19 is closed with a rotary valve 17, and the valve is rotated just before the start of the measurement so that the slit 18 is aligned with the ventilation port 19 to allow air to pass. Become like After the measurement is completed, if the air vent is closed as before, it is possible to prevent intrusion of earth and sand and reduce clogging.

The measuring apparatus of the present invention having the above-described configuration can start measurement immediately after various members are connected and assembled by the air transport pipe 5. As described above, the measuring method is to inject air into the compressed air storage container 4 and insert the air injection pipe into the soil to inject the air. The assembling of the device is simple, the operation of measuring the air flow rate is easy, and many measurements can be performed quickly.

[0030]

As described above, the apparatus for simply measuring soil permeability according to the present invention comprises a storage container for compressed air, an air pressure regulating valve, an air flow regulating valve, an air flow meter, and an air injection pipe. It has a simple structure in which compressed air is injected into soil such as a horticultural park through an air injection pipe, and the injection speed is directly measured. From the air injection rate obtained here, the air permeability of the soil is determined in real time, and it is possible to easily diagnose whether the air permeability of the soil has a problem with the growth of the plant. Furthermore, if this apparatus measures the air permeability of various soils, it is expected that various new findings will be obtained regarding the growth of plants and the air permeability of the soil. Further, if air is sent to soil having poor air permeability by this device, there is an indirect effect that oxygen can be supplied to the soil.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing the entirety of an embodiment of a soil permeability measuring apparatus according to the present invention.

FIG. 2 is a schematic sectional view of an air flow control valve of the embodiment.

FIG. 3 is a schematic sectional view of an air pressure adjusting valve according to the embodiment.

FIG. 4 is a schematic cross-sectional view of the air injection tube of the embodiment.

[Explanation of symbols]

1 Soil permeability simple measurement device 30
Air flow control valve 2, 3 cock (or valve) 31, 56
Body 4 Compressed air storage container 34
Valve opening / closing degree fixing plate 5 Pneumatic transport pipes 36, 47,
52, valve body 6 air flow meter 37, 46
Valve seat 7 Transparent cylindrical container 38, 43,
Packing 8 Area flow meter 39, 49,
Valve adjusting screw 9 Float 40
Air pressure regulating valve 10 Support rod 40a
1st valve 11 air injection pipe 40b
Second valve 12, 32 Valve rotation button 40c
Third valve 13, 33 Valve opening / closing indicator 42
Upper lid 14, 41 Air inlet 44, 57
Spacer 15, 35 Valve stem 45
Support ring 16 Air injection pipe main body 48, 53
Valve adjustment spring 17 Rotary valve 50
Inside the valve 40 18 Slit 51
Guide 19 Vent 54
Lower lid 20 Tip 55
Air outlet

Claims (5)

[Claims] 1. A storage container for compressed air and an air injection pipe for injecting air into the soil connected by a flexible thin air transport pipe via two or more valves and / or cocks and an air flow meter. Simplified soil permeability measurement device characterized by performing. 2. The soil permeability measuring apparatus according to claim 1, wherein an area flow meter is used as an air flow meter in a transparent container. 3. The air flow rate adjusting device according to claim 1, wherein at least one of the two or more valves and / or cocks can be finely adjusted and the degree of opening and closing of the valves can be fixed. A simple soil permeability measuring device characterized by being a valve. 4. The soil permeability measuring apparatus according to claim 1, wherein one of the two or more valves and / or cocks is an air pressure adjusting valve for adjusting air pressure. Soil permeability simple measurement device. 5. The soil permeability measuring apparatus according to claim 1, further comprising, as an air injection pipe, a rotary valve having a slit for allowing air to pass therethrough and being rotatable left and right, inside the vent. A simple measuring device for soil permeability.