JP2003207502A - Compost maturity determining device and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compost maturity determining device and its method, capable of being easily handled, and shortening a measurement time with high measuring accuracy. <P>SOLUTION: This compost maturity determining device comprises a heating and heat-retaining part 10 for heating a compost sample charged into a sample case 11 and keeping the same at a predetermined cultivating temperature, and a control circuit part 20 for controlling the temperature in the sample case 11 in a main body case 30, an oxygen concentration censor 50 is mounted inside of a lid part 40 for opening and closing an upper opening part of the sample case 11, and maturity of the compost sample is determined on the basis of the change of the oxygen concentration in the sample case 11. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compost maturity level determination device and a compost maturity level determination method for determining the maturity level of compost.

[0002]

2. Description of the Related Art Conventionally, a number of proposals have been made regarding methods for determining the maturity of compost, but these methods often require a long time for analysis and sophisticated techniques, and are not practical. The current situation. For example, the maturity level determination method based on BOD (biological oxygen demand) measurement involves culturing water extracted from compost and determining the maturity level of the 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, there is a measuring method described in JP-A-57-56752 as an improved method of the ripening degree determination method, which has a troublesome operation such as pH adjustment,
It had further improvements such as requiring a measurement time of about 24 to 30 hours.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above conventional circumstances, and an object of the present invention is to determine the maturity level of compost which is short in measurement time, high in measurement accuracy, and easy to handle. An object of the present invention is to provide an apparatus and a method for determining the degree of maturity of compost.

[0004]

In order to solve the above-mentioned problems, the apparatus for determining the degree of maturity of compost according to the first aspect of the present invention is a heating and heat-retaining apparatus for heating a compost sample put into a sample container and maintaining it at a predetermined culture temperature. Part and a control circuit part for controlling the temperature in the sample container are provided in the main body case, and an oxygen concentration sensor facing the sample container is provided to detect a change in the oxygen concentration in the sample container. The apparatus for determining the degree of maturity of compost according to claim 1, wherein the heating and heat retaining section covers the outer circumference of the sample container with a heat transfer body, and an electric heater is brought into contact with the outer peripheral surface of the heat transfer body. And an electric heater covered with a heat insulating material, wherein the control circuit unit has a temperature adjusting means for adjusting electric power supplied to the electric heater so as to keep the inside of the sample container at a predetermined culture temperature, and a predetermined temperature A first oxygen concentration measuring means for starting the first oxygen concentration measurement by the oxygen concentration sensor after a lapse of time, and a second oxygen concentration by the oxygen concentration sensor after a lapse of a predetermined time after the first oxygen concentration measurement is completed. A second oxygen concentration measuring means for starting the measurement is provided, and the result of the arithmetic processing based on the two oxygen concentration measured values is displayed on the display means exposed outside the main body case.

In the method for determining the maturity level of compost according to the second aspect of the present invention, the weight ratio of the water content of the compost sample is adjusted within the range of 60 to 75%, and the compost sample is cultured within the range of 30 to 40 degrees. After holding the temperature for a predetermined incubation time, perform the first oxygen concentration measurement, and after the first oxygen concentration measurement is completed and the culture temperature is maintained, the second oxygen concentration measurement after a predetermined time has elapsed. The maturity of the compost sample is determined based on the difference between the two oxygen concentration measurement values.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show an example of a compost maturity level determination device according to the present invention. As shown in FIG. 2, the apparatus A for determining the degree of maturity of compost includes a heating and heat-retaining unit 10 for heating a compost sample to be put into the sample container 11 in a main body case 30 to maintain a predetermined culture temperature, and a sample container. The sample container 11 is provided with an oxygen concentration sensor 50 facing the inside of the lid 40 that opens and closes the upper opening of the sample container 11. It is configured to detect a change in the oxygen concentration in 11.

The main body case 30 is made of a synthetic resin material or a lightweight metal material processed into a box shape having an opening at the top, and the inside thereof has a space for accommodating the heating and heat retaining section 10 by a partition plate 32. It is partitioned into a space for housing the control circuit unit 20. The upper opening of the main body case 30 is covered with a cover 31 which exposes the opening of the sample container 11 and the display means 21 which will be described later.

The lid 40 is made of the same material as the body case 30 and is formed so as to overlap the upper opening of the body case 30, and is provided with a hinge and an engaging / disengaging metal fitting between the body case 30 and the body case 30. An oxygen concentration sensor 50 is attached so as to open and close and engage and disengage with respect to 30, and the oxygen concentration sensor 50 is attached downward inside the lid portion 40 at a position corresponding to the central portion of the sample container 11 in the main body case 30.

The heating / heat-retaining portion 10 is formed in one space partitioned by a partition plate 32 in the main body case 30, and has an outer periphery of a bottomed cylindrical sample container 11 made of stainless steel, glass, copper, aluminum or the like. The sample container 11
Is covered with the heat transfer body 12 except for the upper opening, and a plurality of electric heaters 13 are brought into contact with and fixed to the outer peripheral surface of the heat transfer body 12, and further the heat transfer body 12 and the electric heater 13 are fixed. It is wrapped with the heat insulating material 14.
The material of the sample container 11 is preferably stainless steel from the viewpoints of thermal conductivity, durability strength, heat retention and the like.

The heat transfer body 12 may have either an integral structure or a divided structure as long as it is formed so as to cover the portion of the sample container 11 excluding the opening. 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 aluminum is particularly preferably used as a material having high thermal conductivity and light weight. In addition, the oxygen concentration sensor 5 is also provided in the lid 40.
A heat transfer body 12 'is provided so that 0 is inserted. Therefore, the sample container 11 has its entire circumference surrounded by the heat transfer bodies 12, 1.
It will be covered by 2 '. Further, the heat transfer body 12 ′ on the lid part 40 side is arranged so as to come into contact with the upper end of the heat transfer body 12 in the main body case 30 when the lid part 40 is closed.

Therefore, the heat of the electric heater 13 conducts the heat transfer bodies 12 and 12 'to uniformly heat the outer periphery of the sample container 11.

The electric heater 13 has a conductor covered with heat resistant rubber, is electrically connected to the control circuit section 20 by an electric wire (not shown), and receives heat from the control circuit section 20 to generate heat.

The heat insulating material 14 is made of expanded polystyrene, sponge, polyethylene foam or the like, and covers the outer circumferences of the heat transfer body 12 and the electric heater 13 to prevent the heat in the sample container 11 from leaking to the outside. The lid 40
The heat transfer body 12 ′ on the side is also outside (heat transfer body 1 in FIG. 2).
The upper side of 2 ') is covered with the heat insulating material 14'.

The oxygen concentration sensor 50 in the lid portion 40 is an oxygen concentration sensor having a well-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 supplied to an electric wire (not shown). To the control circuit unit 20 via the.

The control circuit section 20 includes a CPU, RAM, RO
An electronic circuit including M and the like, temperature adjusting means for adjusting the electric power supplied to the electric heater 13 so as to keep the inside of the sample container 11 at a predetermined culture temperature, and an oxygen concentration sensor 50 for measuring the temperature after a predetermined heat retention time. A first oxygen concentration measuring means for starting the first oxygen concentration measurement, and a second oxygen concentration for starting the second oxygen concentration measurement by the oxygen concentration sensor 50 after a lapse of a predetermined time after the first oxygen concentration measurement is completed. The measurement means is provided, 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.

The temperature adjusting means detects the temperature in the sample container 11 by the temperature sensor 15 and controls the voltage supplied to the electric heater 13 so that the detected temperature becomes the set culture temperature. ON / OFF
It is a feedback circuit that is adjusted by control or the like.

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 bottom from below, and the bottomed hole is inserted into the bottomed hole. The temperature sensor 15 indirectly detects the temperature of the compost sample in the sample container 11. Note that the present inventor has confirmed by experiment 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, so that the temperature sensor 15 detected the temperature difference. Although there is almost no problem even if the temperature is set to the temperature of the compost sample, the temperature difference may be corrected in the control circuit unit 20 to obtain the temperature of the compost sample, if necessary. Further, the culture temperature is 30 to 30 in a preferred example of the present embodiment.
It is set to 40 degrees.

Immediately after the start button (not shown) is pressed, the first oxygen concentration measuring means holds the culture temperature for a predetermined heat retention time by the timer function in the control circuit section 20, and then the oxygen concentration is maintained. This is a circuit for measuring the oxygen concentration for the first time by the concentration sensor 50 and temporarily storing the measured value. The start button may be provided on the upper surface of the body case 30, or a limit switch provided between the lid part 40 and the body case 30 so that the start button is turned on when the lid part 40 is closed. May be Further, the heat retention time is appropriately set according to the type of compost and the like, but according to a preferred example of the present embodiment, it is about 30.
Set to minutes.

The second oxygen concentration measuring means, after the measurement of the oxygen concentration by the first oxygen concentration measuring means is completed,
This is a circuit that holds the culture temperature for a predetermined time by a timer function in the control circuit unit 20, then measures the second oxygen concentration by the oxygen concentration sensor 50, and temporarily stores the measured value. The predetermined time is the time between the first oxygen concentration measurement and the second oxygen concentration measurement, and is set appropriately according to the type of compost and the like, but the present embodiment is preferable. According to one example, it is set to about 30 minutes.

The display means 21 is a liquid crystal display and displays the oxygen consumption calculated in the control circuit section 20. Then, this oxygen consumption amount is converted into the ripening degree using a conversion graph, a conversion table, or the like. The degree of ripening expresses the ripening degree of compost as a percentage. The graph in Fig. 3 shows that the maturity of fresh cow dung is 0% and the maturity of compost that is considered to be fully ripe is 100%, and the mixing ratio of the two composts is changed to 6 levels according to the experiment. This is a measurement of the oxygen consumption of each sample artificially made with different values. The term "ripening" is based on the assumption that oxygen consumption is measured regularly during the compost ripening process, and that the ripeness is reached when the oxygen consumption reaches almost zero. That is,
Compost contains a large amount of easily decomposable organic matter that is decomposed by microorganisms when it is immature, and the respiration of microorganisms is active. As the maturity progresses, the amount of easily decomposable organic matter decreases and the respiration of microorganisms decreases.

The experimental results shown in the graph of FIG. 3 are an example in the case where the compost component is cow dung, and it differs depending on various conditions when the compost is ripened, the compost component, and the like. Therefore, a conversion graph, a conversion table, or the like for converting the maturity degree from the oxygen consumption amount is appropriately created based on experiments according to the type of compost to be measured by the compost maturity degree determination device A.

The oxygen consumption amount is calculated 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 calculated by the following formula. Oxygen weight [μg] = (internal volume of sample container [ml] -volume of compost sample [ml]) x measured oxygen concentration (%) / 1
Oxygen weight per 00 × 1 ml [μg] The oxygen weight is, for example, 1430 [μg] when the temperature is 0 ° C. and 1 atm, and 1270 [μg] when the temperature is 35 ° C. and 1 atm. To do. Next, the difference between the oxygen weights at the two points is calculated by the following equation. Oxygen weight difference [μg] = Oxygen weight obtained from the first measurement [μg] −Oxygen weight obtained from the second measurement [μg] Then, according to the following equation, 1 g of compost per minute The amount of oxygen consumed is calculated. Oxygen consumption [μg / g / min] = difference in oxygen weight [μ
g] ÷ weight of sample [g] ÷ time from first oxygen concentration measurement to second oxygen concentration measurement [min]

Next, the method for determining the degree of maturity of compost using the above-mentioned apparatus A for determining degree of maturity of compost will be described in detail. As described above, this method for determining the degree of maturity of compost utilizes the fact that the maturity of compost has a correlation with the oxygen consumption due to the respiration of microorganisms in the compost.

According to this method for judging the degree of maturity of compost, first,
The collected compost sample has a weight ratio of water content of 6
The water content is adjusted to be within the range of 0 to 75%. This water content adjustment method measures, for example, the water content of a compost sample by a well-known method, and when the measured water content (ratio) is less than 60%, a predetermined amount of water is added to the compost sample. Further, in the case of 75% or more, a well-known moisture adjustment method such as air-drying the compost sample may be used.

The weight ratio of the contained water is based on the experimental result shown in FIG. That is, when the weight ratio of the water content of the compost sample is within the above range (60 in the figure)
%, And 65%, 70%, and 75% of the measured values), the oxygen consumption is almost constant and high. That is, the change in oxygen concentration during a predetermined period of time is remarkable, which is suitable for determining the maturity level. On the other hand, when the weight ratio is out of the above range (measured values of 55% and 80%), the oxygen consumption amount is extremely lower than the above value, that is, the change of the oxygen concentration in a predetermined time is small, so that the reliability of It is difficult to judge high maturity.

Next, the power of the compost maturity degree determination device A is turned on, and the sample container 11 is preset to a predetermined culture temperature (30 to 4).
It is heated to 0 degree). Then, the sample container 11
The above-mentioned compost sample with the adjusted water content is put therein, the lid 40 is closed, and a start button (not shown) is pressed.

When the start button is turned on, the culture temperature is maintained for a predetermined heat retention time, after which the oxygen concentration sensor 50 measures the oxygen concentration for the first time.

After the first oxygen concentration measurement 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.

Next, the control circuit section is 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, the volume of the sample loaded into the sample container 11 and the like. Oxygen consumption is calculated in 20 and display means 21
Is displayed in. Then, as described above, this oxygen consumption amount is converted into the maturity degree using a conversion graph (eg, the graph shown in FIG. 3) created in advance based on experiments or the like, a conversion table, or the like.

The culture temperature is set by the inventor of the present invention based on the following conditions to limit the most suitable temperature range. That is, the culture temperature is preferably a temperature at which oxygen consumption increases due to the activation of microorganisms, and in order to prevent dew condensation in the sample container 11, a temperature slightly higher than the normal outside air temperature is suitable. In addition, since it is necessary to cool the sample container 11 when the temperature is set lower than the outside air, it is appropriate that the temperature is higher than the normal outside air temperature, and if the temperature is too low, microorganisms are inactive. As a result, the oxygen consumption amount is small and the measurement time becomes 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. Considering the above, it was set within the range of 30 to 40 degrees.

Further, in the present embodiment, the oxygen consumption amount displayed on the display means 21 is converted into the maturity degree by a conversion graph or a conversion table, but the relationship between the oxygen consumption amount and the maturity degree is previously set. Is stored in the control circuit unit 20,
You may make it display the maturity degree calculated | required from the relationship directly on the display means 21.

[0032]

Since the present invention is constructed as described above, it has the following effects. According to the first aspect of the present invention, the compost sample that is put into the sample container can be maintained at a predetermined culture temperature, and the change in oxygen concentration before and after the elapse of a predetermined time can be detected. The maturity level of can be determined. Moreover, since the heat transfer body that covers 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 the variation in the temperature distribution in the sample container is improved. The decrease can be prevented.
Further, since the main body case and the lid part are integrally provided with the heating and heat retaining part, the control circuit part, the oxygen concentration sensor and the like, they are easy to carry and handle. Furthermore, according to the second aspect of the present invention, by maintaining the water content and the culturing temperature of the compost sample within a suitable range, it is possible to perform the maturity determination with high accuracy.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of a compost maturity degree determination device according to the present invention.

FIG. 2 is a vertical cross-sectional view of the compost maturity degree determination device.

FIG. 3 is a graph showing the relationship between the oxygen consumption of compost and the degree of ripening.

FIG. 4 is a graph showing the relationship between the water content of compost and the oxygen consumption.

[Explanation of symbols]

10: Heat insulation section 11: Sample container 12: Heat transfer body 13: Electric heater 14: Heat insulating material 20: Control circuit section 21: Display means 30: Body case 40: Lid 50: Oxygen concentration sensor A: Compost maturity determination device

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Minoru Ito             Fukushima Prefecture Nishishirakawa-gun Saigo Village Odakura Odakura Odakura             Hara 1 Inside the Livestock Environmental Technology Research Institute (72) Inventor Tomoko Furukawa             Fukushima Prefecture Nishishirakawa-gun Saigo Village Odakura Odakura Odakura             Hara 1 Inside the Livestock Environmental Technology Research Institute (72) Inventor Nobuyuki Shibayama             Fujidaira 6-11-6 Hongo, Bunkyo-ku, Tokyo             Industry Co., Ltd. (72) Inventor Tamotsu Ichimura             Fujidaira 6-11-6 Hongo, Bunkyo-ku, Tokyo             Industry Co., Ltd. (72) Inventor Sadao Nakano             Fujidaira 6-11-6 Hongo, Bunkyo-ku, Tokyo             Industry Co., Ltd. (72) Inventor Mitsuhiro Goto             Fujidaira 6-11-6 Hongo, Bunkyo-ku, Tokyo             Industry Co., Ltd. F term (reference) 2G004 BJ01 BK03 BK04 BL08 BL19                       BM04 BM06

Claims (2)

[Claims] 1. A main body case is provided with a heating and heat-retaining unit for heating a compost sample to be charged into a sample container to maintain a predetermined culture temperature, and a control circuit unit for controlling the temperature in the sample container, It is a compost maturity degree determination device which comprises an oxygen concentration sensor facing the inside of the sample container and detects a change in the oxygen concentration in the sample container, wherein the heating and heat retaining unit transfers heat to the outer periphery of the sample container. While covering with a body, an electric heater is brought into contact with the outer peripheral surface of the heat transfer body, and further, the heat transfer body and the electric heater are covered with a heat insulating material, and the control circuit unit has a predetermined inside of the sample container. Temperature adjusting means for adjusting the electric power supplied to the electric heater so as to maintain the culture temperature, and the first acid for starting the first oxygen concentration measurement by the oxygen concentration sensor after a lapse of a predetermined heat retention time. Concentration measuring means, comprising a second oxygen concentration measuring means for starting the second oxygen concentration measurement by the oxygen concentration sensor after the first time oxygen concentration measurement is completed and a predetermined time has elapsed, the two times of oxygen A compost maturity degree determination device, characterized in that the result of arithmetic processing based on the concentration measurement value is displayed on a display means exposed outside the main body case. 2. The weight ratio of water content of the compost sample is 60.
Adjusted within the range of ~ 75% and put the compost sample at 30 ~
After holding for a predetermined incubation time at a culturing temperature within the range of 40 degrees, the first oxygen concentration measurement was performed, and after the first oxygen concentration measurement was completed and the culturing temperature was kept, after a predetermined time elapsed. A method for determining the degree of maturity of compost, comprising performing a second oxygen concentration measurement and determining the degree of maturity of the compost sample from the difference between the two oxygen concentration measurement values.