JP3697416B2 - Compost maturity judgment device and compost maturity judgment method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a compost maturity determination device and a compost maturity determination method for determining the maturity of compost.
[0002]
[Prior art]
Conventionally, many proposals have been made regarding methods for determining the degree of maturity of compost. However, these methods often require a long time and advanced techniques for analysis, and are currently not practical.
For example, the maturity determination method by measuring BOD (biological oxygen demand) measures water extracted from compost and determines the maturity of compost from the difference in dissolved oxygen before and after the culture. Since the culture requires 5 days, there is a problem that the measurement time becomes long.
Therefore, as an improvement of the method for determining the degree of maturity, there is a measurement method described in JP-A-57-56752. However, it has troublesome operations such as pH adjustment, and measurement for about 24 to 30 hours. It had further improvements such as taking time.
[0003]
[Problems to be solved by the invention]
The present invention has been made in view of the above-described conventional circumstances, and the object of the process is to provide a compost maturity determination apparatus and a compost maturity determination method that have a short measurement time, high measurement accuracy, and easy handling. There is to do.
[0004]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the compost maturity determination device of the first invention includes a heating and heat retaining unit that heats a compost sample put into a sample container and maintains it at a predetermined culture temperature, and a temperature in the sample container. A compost maturity determination apparatus that includes a control circuit unit that controls the inside of the main body case, an oxygen concentration sensor that faces the sample container, and detects a change in oxygen concentration in the sample container. The heating and heat retaining unit covers the outer periphery of the sample container with a heat transfer member, contacts an electric heater with the outer peripheral surface of the heat transfer member, and further covers the heat transfer member and the electric heater with a heat insulating material. The control circuit unit includes a temperature adjusting means for adjusting power supplied to the electric heater so as to keep the inside of the sample container at a predetermined culture temperature, and the oxygen concentration sensor after a predetermined heat retention time has elapsed. A first oxygen concentration measuring means for starting the first oxygen concentration measurement by the first, and a second oxygen concentration sensor for starting the second oxygen concentration measurement by the oxygen concentration sensor after the first oxygen concentration measurement is completed and a predetermined time has elapsed. An oxygen concentration measuring means, and the result of the arithmetic processing from the two oxygen concentration measurement values is displayed on the display means exposed outside the main body case.
[0005]
Moreover, the compost maturity determination method of 2nd invention adjusts the weight ratio of the moisture content of a compost sample in the range of 60-75%, and the compost sample is predetermined with the culture | cultivation temperature in the range of 30-40 degree | times. After the incubation time is maintained, the first oxygen concentration measurement is performed, the first oxygen concentration measurement is completed, and the second oxygen concentration measurement is performed after a predetermined time while the culture temperature is maintained, It is characterized in that the maturity of a compost sample is judged from the difference between two oxygen concentration measurements.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 and 2 show an example of an apparatus for determining compost maturity according to the present invention.
As shown in FIG. 2, the compost maturity determination apparatus A includes a heating and heat retaining unit 10 that heats a compost sample put into a sample container 11 into a main body case 30 and maintains it at a predetermined culture temperature, and a sample container. And a control circuit unit 20 that controls the temperature in the sample container 11, and an oxygen concentration sensor 50 that faces the sample container 11 inside the lid part 40 that opens and closes the upper opening of the sample container 11, and the sample container 11 is configured to detect a change in the oxygen concentration in the inside.
[0007]
The main body case 30 is formed by processing a synthetic resin material or a lightweight metal material into a box shape having an opening on the upper side, and the interior of the main body case 30 accommodates the heating and heat retaining unit 10 by the partition plate 32, and the control circuit unit. It is partitioned into a space for storing 20.
The upper opening of the main body case 30 is covered with a cover 31 that penetrates and exposes an opening of the sample container 11 described later and the display means 21.
[0008]
The lid 40 is made of the same material as the main body case 30 and is formed so as to overlap the upper opening of the main body case 30, and includes a hinge and an engagement / disengagement bracket between the main body case 30 and the main body case 30. The oxygen concentration sensor 50 is attached to the inside of the lid portion 40 so as to be opened / closed and engaged / disengaged at a position corresponding to the central portion of the sample container 11 in the main body case 30.
[0009]
The heat insulation unit 10 is configured in one space partitioned by the partition plate 32 in the main body case 30, and the outer periphery of the bottomed cylindrical sample container 11 made of stainless steel, glass, copper, aluminum, or the like, The sample container 11 is covered with a heat transfer body 12 except for the upper opening, and a plurality of electric heaters 13 are fixed in contact with the outer peripheral surface of the heat transfer body 12. The heater 13 is covered with a heat insulating material 14.
In addition, it is preferable to use stainless steel as the material of the sample container 11 from the viewpoint of thermal conductivity, durability strength, heat retention and the like.
[0010]
The heat transfer body 12 may be either an integral structure or a divided structure as long as the heat transfer body 12 is formed so as to cover a portion other than the opening of the sample container 11.
The material of the heat transfer body 12 is not limited as long as it is a material having high thermal conductivity such as aluminum, copper, and stainless steel, but it is particularly preferable to use aluminum as a material having high thermal conductivity and light weight.
A heat transfer body 12 ′ is also provided in the lid portion 40 so as to penetrate the oxygen concentration sensor 50. Accordingly, the entire circumference of the sample container 11 is covered with the heat transfer bodies 12 and 12 ′.
Further, the heat transfer body 12 ′ on the lid 40 side is disposed so as to contact the upper end of the heat transfer body 12 in the main body case 30 when the cover 40 is closed.
[0011]
Therefore, the heat of the electric heater 13 conducts the heat transfer bodies 12 and 12 ′, thereby uniformly heating the outer periphery of the sample container 11.
[0012]
The electric heater 13 has a conductor covered with heat-resistant rubber, and is electrically connected to the control circuit unit 20 by an electric wire (not shown), and generates heat when supplied with electric power from the control circuit unit 20.
[0013]
The heat insulating material 14 is made of foamed polystyrene, sponge, polyethylene foam or the like and covers the outer periphery of the heat transfer body 12 and the electric heater 13 so that the heat in the sample container 11 is not leaked to the outside. In addition, the heat transfer body 12 ′ on the lid 40 side is also covered with a heat insulating material 14 ′ on the outer side (the upper side of the heat transfer body 12 ′ in FIG. 2).
[0014]
The oxygen concentration sensor 50 in the lid portion 40 is an oxygen concentration sensor having a known structure such as a galvanic cell type or a zirconia solid electrolyte type, and an electric signal corresponding to the oxygen concentration in the sample container 11 is sent via an electric wire (not shown). Transmit to the control circuit unit 20.
[0015]
The control circuit unit 20 is an electronic circuit including a CPU, a RAM, a ROM, and the like, a temperature adjusting unit that adjusts the power supplied to the electric heater 13 so as to keep the inside of the sample container 11 at a predetermined culture temperature, First oxygen concentration measuring means for starting the first oxygen concentration measurement by the oxygen concentration sensor 50 after the heat retention time has elapsed, and a second time by the oxygen concentration sensor 50 after the first oxygen concentration measurement has been completed and a predetermined time has elapsed. A second oxygen concentration measuring means for starting the oxygen concentration measurement, and the result of the arithmetic processing based on the two oxygen concentration measurement values is displayed on the display means 21 exposed outside the main body case 30.
[0016]
The temperature adjusting means detects the temperature in the sample container 11 with the temperature sensor 15, and controls the power supplied to the electric heater 13 by voltage control or ON / OFF so that the detected temperature becomes the set culture temperature. It is a feedback circuit that is adjusted by control or the like.
[0017]
The temperature sensor 15 is a well-known temperature sensor using a resistance temperature detector, a thermocouple, or the like. A bottomed hole is formed in the bottom of the heat transfer body 12 from below, and is inserted into the bottomed hole. . The temperature sensor 15 indirectly detects the temperature of the compost sample in the sample container 11.
In addition, since this inventor has confirmed that the temperature difference between the temperature detected by the temperature sensor 15 and the temperature of the compost sample itself is 0.5 degrees or less by experiment, it was detected by the temperature sensor 15. Even if the temperature of the compost sample is hardly affected, the temperature difference of the compost sample may be obtained by correcting the temperature difference in the control circuit unit 20 as necessary.
Moreover, the said culture | cultivation temperature is set to 30-40 degree | times in the preferable example of this Embodiment.
[0018]
The first oxygen concentration measurement means holds the culture temperature for a predetermined incubation time by a timer function in the control circuit unit 20 immediately after a start button (not shown) is pressed, and thereafter, the oxygen concentration sensor 50 Is a circuit that measures the oxygen concentration for the first time and stores the measured value temporarily.
The start button may be provided on the upper surface of the main body case 30 or a limit switch provided between the lid portion 40 and the main body case 30 so that the start button is turned on when the lid portion 40 is closed. It may be.
Moreover, although the said heat retention time is suitably set according to the kind of compost etc., according to the preferable example of this Embodiment, it is set to about 30 minutes.
[0019]
The second oxygen concentration measuring unit holds the culture temperature for a predetermined time by a timer function in the control circuit unit 20 after the measurement of the oxygen concentration by the first oxygen concentration measuring unit is completed, and then the oxygen concentration sensor 50 is a circuit for measuring the second oxygen concentration by 50 and temporarily storing the measured value.
The predetermined time is the time from the first oxygen concentration measurement to the second oxygen concentration measurement, and is set as appropriate according to the type of compost, etc., which is preferable in the present embodiment. According to an example, it is set to about 30 minutes.
[0020]
The display means 21 is a liquid crystal display and displays the oxygen consumption calculated in the control circuit unit 20. And this oxygen consumption is converted into a maturity using a conversion graph, a conversion table, etc. The degree of maturity represents the degree of maturity of compost as a percentage.
The graph of FIG. 3 shows that the maturity of fresh cow dung is 0%, the maturity of compost considered to be fully ripe is 100%, and the mixing ratio of these two composts is changed to 6 levels. Samples with a difference between the two are artificially made and the oxygen consumption of each is measured.
The term “ripening” is based on the assumption that the amount of oxygen consumption is regularly measured during the maturation process of compost, and that the amount of oxygen consumption is almost zero when the amount of oxygen consumption is almost zero. That is, compost contains a large amount of easily decomposable organic substances that are decomposed by microorganisms when immature, and the respiration of microorganisms is active, and as the maturation progresses, the easily decomposable organic substances decrease and the respiration of microorganisms decreases.
[0021]
Moreover, the experimental result shown in the graph of FIG. 3 is an example in the case where the compost component is cow dung, and differs depending on various conditions when the compost is ripened, compost components, and the like. Therefore, a conversion graph, a conversion table, and the like for converting the maturity from the oxygen consumption are appropriately created based on experiments according to the type of compost to be measured by the compost maturity determination device A.
[0022]
The calculation of oxygen consumption is performed in detail as follows.
First, for each of the first oxygen concentration measurement value and the second oxygen concentration measurement value, the oxygen weight is obtained by the following equation.
Oxygen weight [μg] = (Inner volume of sample container [ml] −volume of compost sample [ml]) × measured oxygen concentration (%) ÷ 100 × oxygen weight per 1 ml [μg]
The oxygen weight is, for example, 1430 [μg] when the temperature is 0 degree and 1 atmosphere, and 1270 [μg] when the temperature is 35 degrees and 1 atmosphere.
Next, the difference in oxygen weight at the two points is obtained by the following equation.
Difference in oxygen weight [μg] = oxygen weight obtained from the first measurement [μg] −oxygen weight obtained from the second measurement [μg]
And the oxygen consumption consumed for 1 minute by 1 g of compost is calculated | required by following Formula.
Oxygen consumption [μg / g / min] = difference in oxygen weight [μg] ÷ sample weight [g] ÷ time from first oxygen concentration measurement to second oxygen concentration measurement [min]
[0023]
Next, the compost maturity determination method using the compost maturity determination device A will be described in detail.
As described above, this compost maturity determination method utilizes the fact that the maturity of compost has a correlation with the amount of oxygen consumed by respiration of microorganisms in the compost.
[0024]
According to this compost maturity determination method, first, the water content of the collected compost sample is adjusted so that the weight ratio of the contained water is in the range of 60 to 75%.
In this moisture adjustment method, for example, the moisture content of a compost sample is measured by a well-known method, and when the measured moisture content (ratio) is less than 60%, a predetermined amount of water is added to the compost sample. In the case of 75% or more, a known moisture adjustment method may be used, such as air drying of a compost sample.
[0025]
The weight ratio of the water content is based on the experimental results shown in FIG. That is, when the weight ratio of the moisture content of the compost sample is within the above range (measured values of 60%, 65%, 70%, and 75% in the figure), the oxygen consumption is almost constant and high. That is, the change in the oxygen concentration during a predetermined time is remarkable, which is suitable for determining the degree of maturity.
On the other hand, when the same weight ratio is outside the above range (measured values of 55% and 80%), the oxygen consumption is extremely lower than the above, that is, the change in the oxygen concentration in a predetermined time is small, so High maturity determination is difficult.
[0026]
Next, the compost maturity determination apparatus A is turned on, and the sample container 11 is heated in advance to a predetermined culture temperature (30 to 40 degrees).
Then, the compost sample in which the moisture content is adjusted is put into the sample container 11, the lid 40 is closed, and a start button (not shown) is pushed.
[0027]
When the start button is turned on, the culture temperature is maintained for a predetermined heat retention time, and then the first oxygen concentration measurement is performed by the oxygen concentration sensor 50.
[0028]
Then, after the measurement of the first oxygen concentration is completed and the culture temperature is maintained for a predetermined time, the second oxygen concentration measurement by the oxygen concentration sensor 50 is performed.
[0029]
Next, in the control circuit unit 20 based on data such as the first oxygen concentration measurement value and the second oxygen concentration measurement value, the internal volume of the sample container 11 and the volume of the sample put into the sample container 11. The oxygen consumption is calculated and displayed on the display means 21.
And as above-mentioned, this oxygen consumption is converted into a maturity degree using the conversion graph (for example, graph shown in FIG. 3), the conversion table, etc. which were created based on experiment etc. previously.
[0030]
In addition, the said culture | cultivation temperature limited the most suitable temperature range based on the following conditions by this inventor.
That is, the culture temperature is preferably a temperature at which oxygen consumption increases due to the activation of microorganisms, and a temperature slightly higher than the normal outside air temperature is appropriate for preventing condensation in the sample container 11. In addition, since it is necessary to cool the sample container 11 when it is set lower than the outside air, a temperature higher than the normal outside air temperature is appropriate, and microorganisms are inactive at a temperature too low. As a result, the oxygen consumption is small and the measurement time is long, and in order to use the oxygen concentration sensor 50 within the operating temperature range, it is appropriate to set it to 40 degrees or less. In consideration of the above, it was set within a range of 30 to 40 degrees.
[0031]
In the present embodiment, the oxygen consumption amount displayed on the display means 21 is converted into the maturity level by a conversion graph, a conversion table, or the like. However, the relationship between the oxygen consumption amount and the maturity level is controlled in advance by the control circuit. It may be stored in the unit 20 and the maturity obtained from the relationship may be directly displayed on the display means 21.
[0032]
【The invention's effect】
Since the present invention is configured as described above, the following effects can be obtained.
According to the first invention, the compost sample put into the sample container is maintained at a predetermined culture temperature, and a change in oxygen concentration before and after a predetermined time can be detected. The degree of maturity can be determined.
In addition, since the heat transfer body covering the sample container uniformly transfers the heat of the electric heater to the sample container, the sample container can be heated to the culture temperature in a short time, and the measurement accuracy due to variations in the temperature distribution in the sample container can be improved. A decrease can be prevented.
In addition, since the main body case and the lid are integrally provided with a heat insulation unit, a control circuit unit, an oxygen concentration sensor, etc., they are easy to carry and handle.
Furthermore, according to 2nd invention, a highly accurate maturity determination can be performed by maintaining the moisture content and culture | cultivation temperature of a compost sample in a suitable range.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an example of a compost maturity determination apparatus according to the present invention.
FIG. 2 is a longitudinal sectional view of the compost maturity determination device.
FIG. 3 is a graph showing the relationship between compost oxygen consumption and maturity.
FIG. 4 is a graph showing the relationship between the moisture content of compost and the oxygen consumption.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10: Heat insulation part 11: Sample container 12: Heat transfer body 13: Electric heater 14: Heat insulation material 20: Control circuit part 21: Display means 30: Main body case 40: Lid part 50: Oxygen concentration sensor A: Compost maturity judgment apparatus

Claims (2)

The main body case includes a heating and heat retaining unit that heats the compost sample to be put into the sample container and maintains the culture temperature at a predetermined culture temperature, and a control circuit unit that controls the temperature in the sample container. A composting maturity determination device provided with an oxygen concentration sensor facing and detecting a change in oxygen concentration in the sample container,
The heating and heat retaining unit wraps the outer periphery of the sample container with a heat transfer member, brings an electric heater into contact with the outer peripheral surface of the heat transfer member, and further wraps the heat transfer member and the electric heater with a heat insulating material. Become
The control circuit section includes temperature adjusting means for adjusting power supplied to the electric heater so as to keep the inside of the sample container at a predetermined culture temperature, and a first oxygen concentration sensor by the oxygen concentration sensor after a predetermined heat retention time has elapsed. First oxygen concentration measuring means for starting concentration measurement; and second oxygen concentration measuring means for starting second oxygen concentration measurement by the oxygen concentration sensor after the first oxygen concentration measurement is completed and a predetermined time has elapsed. A composting maturity determination device comprising: a display unit exposed outside the main body case, and a result obtained by performing arithmetic processing from the two oxygen concentration measurement values. The weight ratio of the moisture content of the compost sample is adjusted to within a range of 60 to 75%, and the compost sample is held at a culture temperature within a range of 30 to 40 degrees for a predetermined incubation time, and then the first oxygen concentration measurement The second oxygen concentration measurement is performed after a predetermined time has passed while the first oxygen concentration measurement is completed and the culture temperature is maintained, and the compost sample is ripened from the difference between the two oxygen concentration measurement values. A method for determining compost maturity, characterized in that the degree is determined.

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