JPS6329175B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a safety circuit for a hot water floor heating system.

(Prior Art) Fig. 1 shows a general hot water floor heating system.
A constant temperature (e.g. 80
°C) is circulated through the floor heating hot water panel 3 through the piping 2 and returned to the heat source equipment through the piping 2', and the hot water flow path is opened and closed by a thermal valve 4 provided in the piping 2. The temperature of the floor heating hot water panel 3 is controlled by this. Thermal valve 4
By energizing the adjacent heater (for example, POSISTOR) 5, the heated valve 4 opens and hot water flows to the floor heating panel 3, and by stopping the energization to the heater 5, the valve 4 is closed and the supply of hot water is stopped. I'm starting to do that. The heater 5 is energized by the floor temperature sensor 6.
A temperature control circuit 8 is configured to perform the control based on the output signal of the room temperature sensor 7, thereby controlling the bed temperature and the room temperature.

FIG. 2 shows an example of a temperature control circuit used in this type of device. In the figure, 14 is a power supply circuit, 9 is a resistance thermistor circuit, which obtains a bed temperature detection voltage and a room temperature detection voltage by a floor temperature sensor 6 and a room temperature sensor 7, and a voltage amplification circuit that converts the difference voltage between the bed temperature detection voltage and room temperature detection voltage. The duty of the oscillation output of the variable duty oscillation circuit 13 is varied depending on the magnitude of the output voltage of the voltage amplification circuit 12, and the oscillation output of the variable duty oscillation circuit is used to drive the thermal valve 4 through the relay circuit 11. The circuit configuration is such that the current supply to the heater 5 is controlled.
In other words, it is a circuit that shortens or lengthens the period of one level of oscillation output in response to the rise or fall of the bed temperature detected by the bed temperature detection circuit that detects the bed temperature, and when the bed temperature is higher than a predetermined temperature. Then, the circuit of relay Ry is cut off, thereby stopping heating of heater 5,
When valve 4 is closed and the bed temperature falls below a predetermined temperature,
It acts to open the valve 4, and the period of opening and closing of the valve 4 is controlled by the magnitude of the difference between the bed temperature and the room temperature.

However, the floor temperature sensor 6 is generally arranged at the inlet of the hot water floor panel and wired to the temperature control circuit sensor section by a lead wire. Therefore, the bed temperature sensor 6
Since the wires are placed on the floor, they are susceptible to mechanical stress due to their structure, and there is a risk of wire breakage. A negative characteristic thermistor (NTC) is often used as a bed temperature sensor.
In this case, the fact that the resistance value becomes infinite due to a disconnection is a signal equivalent to a very low floor temperature, and the temperature control circuit is always in a continuous state of energization, which causes the floor temperature to rise abnormally. , there was a risk of danger.

In addition, due to disconnection of the room temperature sensor, failure due to welding of the contacts of the relay that controls the heater 5 of the thermal valve 4, failure of the relay drive transistor or the comparator that controls the relay, etc., the continuous connection to the hot water panel due to an uncontrolled state It is possible that the valve is closed due to a water supply failure or the thermal valve itself is stuck, and in these cases there is a risk of an abnormal temperature rise in the floor heating hot water panel. The present invention has been proposed to eliminate the above-mentioned disadvantages and risks.

(Purpose of the Invention) The present invention provides a temperature control circuit for a hot water circulation type floor heating system in which the temperature detection sensor malfunctions (disconnection) or the opening/closing device of the hot water flow path, the contacts, circuits, etc. that control the opening/closing device malfunction. The purpose is to provide a safety circuit to prevent loss of control.

(Structure of the invention) Figure 3 shows the temperature control circuit of the invention.
In the figure, 1 is a heat source device, and 1a is a heat source device control circuit. The heat source device control circuit is activated by turning on the switch SW and connecting the contact R'y ₂ of the relay Ry ₂ . Ry ₁ is a relay, and the operation of this relay turns on and off the heating of the heater 5 and opens and closes the thermal valve 4. 14 indicates a power supply circuit. A room temperature sensor 7 is connected in series with a resistor R ₁ , and both ends of this series circuit are connected to a power supply circuit 14 . A floor temperature sensor 6 is connected in series with a resistor R _E , and both ends of this series circuit are connected to a power supply circuit 14 . Therefore, the connection point between the room temperature sensor 7 and the resistor R ₁ and the floor temperature sensor 6
The connection points between R E and the first resistor R _E are respectively given to a temperature processing circuit, and this temperature processing circuit is given a signal voltage obtained from the room temperature and the floor temperature, and outputs a signal corresponding to the difference between the two signal voltages. This is a circuit that does this. The temperature adjustment circuit is a circuit that sets high and low temperature levels according to the preferences of the person using the temperature control device (for example, the voltage at the variable contact of a variable resistor whose both ends are connected to the power supply circuit is used as the reference voltage). be able to.)
and the output of both circuits is the first comparator
Given to OP ₁ . In this embodiment, the third resistor R _B has a resistance equal to the resistance value when the floor temperature sensor reaches -30°C, and is connected in series with the second resistor R _A , and both ends of this series circuit are It is connected to the power supply circuit 14. Also, the fifth resistor R _D has a floor temperature sensor of +75℃.
with a resistance equal to the resistance value when the fourth
is connected in series with the resistor R _C , and both ends of this series circuit are connected to the power supply circuit 14 . Also, resistance R _E =
R _A = R _C is selected.

Therefore, the first voltage at the connection point between the floor temperature sensor 6 and the resistor R _E is V _A , and the second voltage at the connection point between the resistors R _A and R _B is V A .
When the voltage at the terminal is V _B and the third voltage at the connection point between the resistors R _C and R _D is V _C , the non-inverting input terminal of the second comparator OP ₂ has V _C and the inverting input terminal has V C. _A ,
The non-inverting input terminal of the third comparator _OP3 has
V _A and V _B are applied to the inverting input terminal, respectively. Furthermore, the outputs of comparators OP ₂ and OP ₃ are each connected to a resistor.
It is applied to the gate of thyristor SCR ₁ via R ₂ and R ₃ . Relay Ry ₂ and thyristor SCR ₁ are connected in series, and both ends of this series circuit are connected to power supply circuit 14.
connected to. Also, the output of comparator OP ₁ is a resistor
It is applied to the base of the transistor Tr ₁ via R ₆ , and this transistor Tr ₁ is connected in series with the relay Ry ₁ , and both ends of this series circuit are connected to the power supply circuit 14 .

Next, the operation will be explained.

The values of resistors R _A and R _C are selected to be equal to the value of R _E . Further, R _B is selected to have a resistance value corresponding to -30°C of the bed temperature sensor, and R _D is selected to have a resistance value corresponding to 75°C of the bed temperature sensor.
When the circuit is normal (usually when the bed temperature is between 10°C and 60°C), the values of each voltage V _A , V _B , and V _C are V _B > V _A
>V _C , the output voltages of the comparators OP ₂ and OP ₃ become low level voltages, and the gate of the thyristor SCR is not driven.

Next, consider the case when the floor temperature sensor 6 is disconnected. In this case, V _A = V _CC , and the relationship between the voltages of V _A , V _B , and V _C is as follows:
V _A > V _B > V _C , the output voltage of comparator OP ₃ becomes high, and thyristor SCR is driven.
Relay contact R′y ₂ is turned off (using NC contact:
The contact is on when the relay coil is not energized, and when voltage is applied to the relay coil, that is, when the SCR is on,
(the contact is opened), the heat source device 1 is stopped, and the supply of hot water is stopped.

Next, temperature control became impossible due to disconnection of the room temperature sensor, welding of the thermal valve control relay contact, continuity failure of the relay drive transistor, and comparator OP ₁ , and as a result, the floor temperature exceeded 75℃. At this time, the voltages of V _A , V _B , and V _C become V _B > V _C > V _A ,
The output voltage of the comparator OP ₂ becomes high, the thyristor SCR is driven, the relay contact R'y ₂ is turned off, the heat source device 1 is stopped, the hot water supply is stopped, and safe operation is ensured. Furthermore, thyristor SCR
By connecting a light emitting diode LED to the cathode of the circuit and grounding it, it is also possible to display an indication when there is a circuit problem.

(Effects of the Invention) As described in the present invention, the voltage V _A at the connection point between the resistor R _E and the floor temperature sensor 6, the resistor R _B corresponding to the resistance value of the resistor R _A and the floor temperature sensor at low temperatures. When the voltage V _B at the connection point between the resistor R _C and the resistance R _D corresponding to the resistance value of the floor temperature sensor at high temperature is V _C , the voltages V _B and V _C are respectively , to the third comparator, and the outputs of these comparators are configured to drive the control circuit of the heat source device. The safety of the device can be ensured even in the event of a failure or failure of the thermal valve. If necessary, a light emitting diode or the like may be used to indicate the presence of a malfunction to notify the user of the occurrence of a malfunction.

[Brief explanation of the drawing]

FIG. 1 shows a hot water floor heating system, FIG. 2 shows a conventional temperature control circuit, and FIG. 3 shows a safety circuit of the hot water floor heating system of the present invention. 1... Heat source machine, 2... Piping, 3... Floor heating hot water panel, 4... Thermal valve, 5... Heater, 6... Floor temperature sensor, 7... Room temperature sensor, 8... Temperature control circuit , 14...power supply circuit, _OP1 , _OP2 , _OP3 ...first, second, third comparators, R _E , R _A , R _B ,
R _C , R _D ...first, second, third, fourth, and fifth resistors.

Claims (1)

[Claims] 1 A signal detected by a room temperature sensor and a floor temperature sensor in a floor temperature control circuit that controls the supply of hot water at a constant temperature to a floor heating hot water panel by opening and closing a thermal valve to control the floor temperature within a constant temperature range. is applied, and the output of a temperature processing circuit that generates a signal corresponding to the difference voltage between both signal voltages is applied to the non-inverting input terminal of the first comparator, and the desired temperature level is applied to the inverting input terminal of the first comparator. The output of the temperature adjustment circuit to be set is given, the output of the comparator is given to the base of a transistor connected in series with the relay that drives the thermal valve, and a first resistor to which a power supply voltage is applied to both ends. In a series circuit with a floor temperature sensor, a voltage at a connection point between the first resistor and the Shothermal temperature sensor is used as the first voltage, and a series circuit of a second resistor and a third resistor to which a power supply voltage is applied to both ends. In the series circuit of the fourth and fifth resistors, the voltage at the connection point of the second and third resistors is the second voltage, and the power supply voltage is applied to both ends of the fourth resistor.
When the voltage at the connection point between and the fifth resistor is a third voltage, the first voltage is applied to the inverting input terminal of the second comparator, the third voltage is applied to the non-inverting input terminal, and the third voltage is applied to the inverting input terminal of the second comparator. A first voltage is applied to the non-inverting input terminal of the comparator, a second voltage is applied to the inverting input terminal, and
A safety circuit for a hot water floor heating system, characterized in that the outputs of the second and third comparators are applied to a gate of a thyristor connected in series with a relay that controls a heat source device.