JPS621500A - Heating control apparatus of methane fermentation tank - Google Patents

Abstract

PURPOSE:To smoothly perform methane fermentation by controlling temp., by mounting a liquid temp. detection circuit, an ignition detection circuit, an ignition timer circuit and a preset counter circuit. CONSTITUTION:When the temp. of the liquid in a fermentation tank reached predetermined temp. or less, the first relay 5 of a liquid temp. detection circuit A is operated to turn a gas boiler 6 ON. When the concn. of methane gas is low and the gas boiler 6 is not ignited, an ignition timer circuit C repeats ignition operation so as to leave a definite stop time. A preset counter circuit D counts the number of times of ignition operations and, when the ignition operation reaches the predetermined number of times, stops the supply of a current to the gas boiler 6 to supply a current to an electric water heater 20. When the temp. of the fermentation tank reaches predetermined temp., the supply of a current to the gas boiler 6 and the electric water heater 20 is stopped. By this method, fermentation gas can be effectively and rationally used.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] The present invention relates to a heating control device for a methane fermentation tank. In a methane fermentation device, a portion of the fermented methane is supplied to a gas boiler as fuel, and the warm water is used to heat the digestive fluid in the fermenter. However, if the methane concentration in the fermentation gas decreases due to poor fermentation or overload, and heating with boiler hot water is not performed sufficiently, it becomes impossible to maintain the appropriate temperature of the digestive fluid, and fermentation stops. and may eventually stop fermentation. In order to prevent such a phenomenon from occurring, the present invention provides a heating control device for a methane fermentation tank that maintains the temperature of digestive fluid at an appropriate temperature at all times to ensure smooth fermentation of methane. The purpose is to

[Structure of the Invention] The heating control device for a methane fermentation tank of the present invention includes a liquid temperature thermistor that detects the temperature of digestive fluid in the methane fermentation tank, and a comparator that compares the temperature detected by the liquid temperature thermistor with a reference temperature. and a first circuit operated by the output of the comparator.
a liquid temperature detection circuit A comprising a relay; an ignition thermistor that detects ignition of a gas boiler that starts combustion by the operation of the first relay; a comparator that compares the output of the ignition thermistor with a reference voltage; an ignition detection circuit B comprising a second relay operated by the output of the first relay; and a second relay that repeats the re-ignition operation for a fixed period of time after a fixed pause period when the gas boiler does not ignite due to the operation of the first relay. an ignition timer circuit C including one timer and a first timer relay, a second timer and a second timer relay, and a count coil that counts the number of times the ignition operation is repeated by the ignition timer circuit C.

A reset coil that resets this count coil,
a precent counter circuit comprising a third relay that operates when the number of ignition operations counted by the count coil reaches a predetermined value; and an electric hot water heater driven by the third relay. When the temperature of the digestive fluid reaches a predetermined temperature due to heating by an auxiliary heating device such as a boiler, the power supply to the gas boiler and the auxiliary heating device is stopped, and the power runt of the counter circuit is reset. It is characterized by

Embodiments of the present invention will be described with reference to the drawings. A is a liquid temperature detection circuit that detects the temperature of the methane fermentation tank (temperature of digestive fluid), which includes a liquid temperature thermistor 1 that detects the liquid temperature, and resistors 2a and 2b that set a reference temperature.

2c, a voltage comparator 3 for comparing these, a switching transistor 4, and a first relay 5. 5a is a normally open contact of the first relay 5, and 5b is a normally closed contact. B is a gas boiler 60 that supplies hot water for heating to the methane fermentation tank.
The ignition detection circuit detects the presence or absence of ignition, and includes an ignition thermistor 7, resistors 8a18b and 8c for setting a reference voltage, a voltage comparator 9, a switching transistor 1o, and a second relay 11. lla and llb are second relay 1
1 normally open contact. C is an ignition timer circuit, which includes a first timer 12 and a first timer relay 13 connected in parallel with this, and a second timer 14 and a second timer line 15 connected in parallel with this. 12a is a time-limited open contact of the first timer 12, 12b is a time-limited close contact, and 13a is the first timer 12.
Normally open contact of timer relay 13, 14a is second timer 14
15a is a normally open contact of the second timer relay 15, and 15b is a normally closed contact. D is a preset counter circuit consisting of a count coil 16, a reset coil 17, and a third relay 19 connected by a normally open counter contact 18. 19a is a normally open contact of the third relay 19;
19b is a normally closed contact, and 20 is an electric water heater provided as an auxiliary to the gas boiler 6.

Next, its effect will be explained. When the liquid temperature detected by the liquid temperature thermistor 1 becomes lower than the reference temperature (35C) set by the resistors 2b and 2c, the transistor 4 is turned on by the output of the voltage comparator 3, and the first relay 5 is turned on. When the first relay 5 is turned on, the normally open contact 5a is closed, the gas boiler 6 is turned on, and at the same time the first timer 12 and the first
Timer relay 13 is turned on. The first timer 12 opens the time-limited close contact 12b and closes the time-limited open contact 12a when the set on-time t has elapsed. When the time-limited closing connection 12b is turned off, the gas boiler 6 and the first timer relay 13 are turned off. On the other hand, when the second timer 14 is turned on by turning on the time-limited contact 12a, the time-limited contact 14a of the second timer 14 turns on the second timer relay 15 for the set time t2. When the second timer relay 150 is turned on, its normally open contact 1
5a is not on, the second timer 14 is kept on by itself.

On the other hand, the normally closed contact 15b of the second timer relay 15 is open. When time t has elapsed, the time limit contact 14a of the second timer 14 is turned off, so the second timer relay 15 is no longer turned off, and its normally closed contact 15b is turned on again. Therefore, the first timer 12, first timer relay 13, and gas boiler 6 are turned on. Then, the gas boiler 6 is ignited, and the temperature detected by the ignition thermistor 7 of the ignition detection circuit B reaches the resistance 8.
b.

The above on/off operation is repeated until the reference temperature set by 8C is reached. When the temperature detected by the ignition thermistor reaches the reference temperature, the second relay 11
closes the normally open contact 11a to keep the gas boiler 6 on.

If gas boiler 6 does not ignite for some reason, s
The ignition operation is performed by repeating the cycle of turning on for time t1 and turning off for time t3, but when the number of ignitions counted by the count coil 16 reaches a preset number of times (for example, 5 times) in the preset counter circuit, the normally open state is activated. Counter contact 18 closes and third relay 19 turns on. When the third relay 19 is turned on, its normally closed contact 19b is turned off, and the Shigas boiler 6 is turned off. At the same time, the normally open contact 19a of the third relay 19 is turned on, power is supplied to the electric water heater 20, and the electric water heater 20 performs heating. When the temperature of the digestive fluid reaches a specified temperature (35C) and the fluid temperature thermistor 1 detects this, the first relay 5 is activated and its normally closed contact 5b is turned on, so the reset coil 17 is reset and Counter contact 18 is turned off.

At the same time, the normally open contact 5a of the first relay 5 is also turned off, so
Both the gas boiler 6 and the electric water heater 20 are turned off and power supply is stopped.

[Effects of the Invention] As described above, in the device of the present invention, when the temperature of the liquid in the fermenter falls below a predetermined temperature, the liquid temperature detection circuit A is activated.
The first relay 5 is activated.

Turn on gas boiler 6. When the concentration of methane gas is low and the gas boiler 6 does not ignite, the ignition timer circuit C repeats the ignition operation after a certain pause time, and the preset counter circuit counts the number of times this ignition operation reaches a predetermined number. Then, power supply to the gas boiler 6 is stopped and power is supplied to the electric water heater 20. When the temperature of the fermenter reaches a predetermined temperature, the gas boiler 6 and the electric water heater 20
It is configured to stop power supply to
It is configured to automatically heat with a separate auxiliary heating device (electric water heater) only when heating with fermentation gas is impossible, so fermentation gas is used effectively and rationally, and methane fermentation It has an excellent effect of smoothing the process.

[Brief explanation of the drawing]

The figure is an electrical circuit diagram of an embodiment of the heating control device of the present invention. A...Liquid temperature detection circuit, 1...Liquid temperature thermistor, 2a
, 2b, 2c...Resistor, 3...Voltage comparator, 4
... Transistor, 5... First relay 6... Gas boiler B... Ignition detection circuit, 7... Ignition thermistor, 8a
18b, 8c...Resistor, 9...Voltage comparator, 1o
...Transistor, 11...Second relay C...Ignition timer circuit, 12...First timer, 13
...First timer relay, 14...Second timer, 15
...Second timer relay D...Preset counter circuit, 16...Count coil, 17...Reset coil, 18...Counter contact, 19...Third relay, 20...Electric hot water Equipment bow-゛y°゛

Claims (1)

[Claims] A liquid temperature thermistor that detects the temperature of the digestive fluid in the methane fermentation tank, a comparator that compares the temperature detected by the liquid temperature thermistor with a reference temperature, and operates based on the output of the comparator. a liquid temperature detection circuit A comprising a first relay; an ignition thermistor that detects ignition of a gas boiler that starts combustion by the operation of the first relay; and a comparator that compares the output of the ignition thermistor with a reference voltage. and a second relay operated by the output of the comparator; and an ignition detection circuit B comprising: a second relay operated by the output of the comparator; An ignition timer circuit C that includes a first timer and a first timer relay that repeats an operation for a certain period of time, and a second timer and a second timer relay, and a number of times that the ignition operation is repeated by the ignition timer circuit C. A precent counter circuit comprising a count coil for counting, a reset coil for resetting the count coil, and a third relay that operates when the number of ignition operations counted by the count coil reaches a predetermined value. D, when the temperature of the digestive fluid reaches a predetermined temperature due to heating by an auxiliary heating device such as an electric water heater driven by the third relay, the gas boiler and the auxiliary heating A heating control device for a methane fermentation tank, characterized by stopping power supply to the device and resetting the count of the counter circuit D.