JPS6344896B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cleaning device equipped with a feed water heater having a function of maintaining a constant temperature of the feed water.

[Prior Art] Conventionally, sanitary washing devices equipped with water heaters have been used. Since the hot water discharged from the hot water tank of the water heater comes into contact with sensitive parts of the body, it is necessary to maintain its temperature at a value that people feel is appropriate.

For this reason, as shown in Japanese Patent Application Laid-Open No. 145228/1982, the temperature of hot water in the hot water tank is detected using a temperature sensing element such as a negative characteristic thermistor and converted to voltage, and this detected voltage is set. A device is known that compares the potential with a reference potential corresponding to the temperature and controls the energization to the heater of the feed water heater according to the comparison result.

In other words, when the temperature of hot water is higher than the set temperature, power to the heater is stopped, and when the temperature of hot water is lower than the set temperature, power is started to the heater, so that the temperature of hot water becomes equal to the set temperature. Temperature control is performed.

Further, a variable resistor for temperature setting is connected in series with the temperature sensing element, and by changing the resistance value of the variable resistor, the set temperature can be changed.

[Problem that the invention seeks to solve]

However, in the temperature control circuit described in JP-A No. 55-145228, the set temperature on the high temperature side becomes abnormally high due to the tolerance of the resistance value of the variable resistor. There is a risk of spewing out hot water.

That is, the resistance value of a variable resistor generally has a ±10
Although there is a tolerance of % or more, the circuit described in the above publication is configured such that when the resistance value of the variable resistor is increased, the temperature is set to a high temperature. Therefore, the resistance value tolerance directly becomes a temperature error, and when the error occurs in the positive direction, the temperature on the high temperature side becomes higher than the intended maximum temperature, creating a risk of burns or the like.

An object of the present invention is to perform temperature control on the maximum temperature side with high precision by configuring a temperature control circuit so that the temperature of hot water becomes high when the resistance value of the variable resistor is set to the minimum. .

[Means for solving problems]

In order to achieve the purpose, the cleaning device of the present invention includes a heating section that heats water in a hot water storage tank, a temperature detection section installed in the hot water storage tank, a signal from the temperature detection section, and a signal for setting the hot water temperature. A feed water heater comprising a temperature control unit that controls the heating unit so that the temperature of the hot water in the hot water tank is always maintained within the optimum temperature range by comparing the potential with a reference potential set by a variable resistor. In the cleaning apparatus, the variable resistor which divides the power supply voltage and inputs it to the comparator as the reference potential is connected in series with the fixed resistor, and when the resistance value of the variable resistor decreases, the The temperature control section is characterized in that the temperature control section is configured to increase the temperature of hot water in the hot water storage tank.

〔Example〕

Hereinafter, the features of the present invention will be specifically clarified by describing embodiments with reference to the drawings.

In the embodiment of the present invention, two temperature sensors are installed in the hot water storage tank, the first temperature sensor is installed near the water inlet at the bottom of the hot water storage tank, and the second temperature sensor is installed near the water inlet at the top of the hot water storage tank. It shall be installed near the hot water outlet.

The figure shows an example of a temperature control circuit attached to the feed water heater of the sanitary washing device in this embodiment.

A DC voltage from a DC power supply 1 is applied between one input terminal and the other input terminal. Also,
AC power supply 2 is connected between the input terminal and the input terminal.
AC voltage is applied from 0.

A series circuit of a negative characteristic thermistor 2, which is the first temperature sensor, and a resistor 3 is connected between the input terminal and the input terminal. As a result, the DC voltage supplied between both input terminals is divided by resistance, and the voltage at the division point A is supplied as a detection voltage to the + side input terminal of the voltage comparison IC 5. Also,
The output terminal of the voltage comparison IC 5 is connected to the + side input terminal of the voltage comparison IC 5 via a resistor 4 and to the input terminal via a resistor 6.

Further, similarly to the above-described configuration, a series circuit of a negative characteristic thermistor 14, which is a second temperature sensor, and a fixed resistor 15 is connected between the input terminal and the input terminal. The DC voltage is resistance-divided, and the voltage at the dividing point E is supplied as a detection voltage to the + side input terminal of the voltage comparison IC 9. In addition, the output terminal of the voltage comparison IC9 is
It is connected to the + side input terminal of the voltage comparison IC 5 via the resistor 8 and to the input terminal via the resistor 7.

Furthermore, a series circuit of a variable low resistance resistor 11 and fixed resistors 12 and 13 (hereinafter simply referred to as resistors) is connected between the input terminal and the resistor. The DC voltage is resistance-divided by the combined resistance of variable resistor 11 and resistor 12 and resistor 13, and this dividing point is connected to voltage comparison IC 5.
and 9, and the voltage at division point 2 is commonly supplied to the negative input terminals of voltage comparison ICs 5 and 9 as a reference potential.

In addition, each output terminal of voltage comparison ICs 5 and 9 is
They are connected to each input terminal of the NAND gate IC 10, respectively. The NAND gate IC10 is a logic unit that combines the output conditions of the voltage comparison IC5 and the output conditions of the voltage comparison IC9.

The output terminal of NAND gate IC10 is connected to resistor 1
6 to the base of the transistor 17. The transistor 17 has its emitter connected to an input terminal, and its collector connected to one input terminal of a solid state relay 18. This solid state relay 18
is for controlling the driving of the heater 19.

The other input side terminal of solid state relay 18 is connected to an input terminal. . Further, one output side terminal of the solid state relay 18 is connected to an input terminal, and the other output side terminal is connected to the input terminal via a heater 19.

The temperature control circuit configured in this way operates as described below, and maintains the temperature of hot water discharged from the feed water heater at a constant value.

When the temperature of the hot water near the heat sensitive part of the negative characteristic thermistor 2, that is, the temperature of the hot water near the water inlet, decreases, the resistance value of the negative characteristic thermistor 2 increases.
As a result, the voltage at point A supplied to the + side input terminal of voltage comparison IC 5 becomes lower than the reference potential at point 2 supplied to the - side input terminal of voltage comparison IC 5. Therefore, the potential at the output point RO of the voltage comparison IC 5 becomes low level.

Conversely, when the temperature of the hot water near the heat sensitive part of the negative characteristic thermistor 2 increases, the resistance value of the negative characteristic thermistor 2 decreases. As a result, the potential at point A becomes higher than the reference potential at point D, and the voltage comparison IC 5
The potential at output point B becomes high level.

That is, the output potential of the voltage comparison IC 5 becomes a low level when the hot water temperature near the water inlet is below the set temperature, and becomes a high level when it is above the set temperature.

On the other hand, a similar operation is performed in the voltage comparison IC 9 as well.

When the temperature of the hot water near the heat sensitive part of the negative characteristic thermistor 14, that is, the temperature of the hot water near the taphole, decreases, the resistance value of the negative characteristic thermistor 14 increases. As a result, the voltage at point 1 becomes lower than the reference potential at point 2. Due to this drop in the voltage at point H, the potential at output point C of the voltage comparison IC 9 becomes low level. Conversely, when the temperature of the hot water near the heat-sensitive portion of the negative characteristic thermistor 14 increases, the resistance value of the negative characteristic thermistor 14 decreases. As a result, the voltage at point 1 becomes higher than the reference potential at 2 points,
The potential at the output point C of the voltage comparison IC 9 becomes high level.

In this way, the output potential of the voltage comparison IC9 is
When the temperature of hot water near the outlet is below the set temperature, the level is low, and when it is above the set temperature, the level is high.

The voltage at output point B of voltage comparison IC5 and the voltage at output point C of voltage comparison IC9 are
It is connected to two input terminals of 10. Therefore, when at least one of the potential at point B and the potential at point C is at a low level, that is, when at least one of the temperature of hot water near the water inlet and the temperature of hot water near the outlet is below the set temperature, , NAND
The potential at the output point of the gate IC 10 becomes high level, and the transistor 17 is activated via the resistor 16.
Turns on. In response to the ON operation of the transistor 17, the solid state relay 18 is turned ON, the heater 19 is energized, and the hot water is heated.

When both the potential at point A and the potential at point C, which are connected to the two input terminals of the NAND gate IC 10, are at high level, that is, both the hot water temperatures detected by the negative characteristic thermistors 2 and 14 are set. If it is above the temperature, NAND gate IC1
The potential to the 0 output point becomes low level. Therefore, transistor 17 is turned off. In response to this OFF operation of transistor 17, solid state relay 18 is turned OFF, power supply to heater 19 is cut off, and heating of hot water is stopped.

In this way, when at least one of the temperature of the hot water near the water inlet and the temperature of the hot water near the outlet is below the set temperature, the heater 19 is energized and the temperature of the hot water in the tank increases.

Therefore, not only when the temperature near the hot water outlet at the top of the hot water storage tank falls below the set temperature, but also when the temperature near the hot water outlet at the top of the hot water storage tank is at the set temperature, water supply causes the water inlet at the bottom of the hot water storage tank to drop. When the temperature of nearby hot water drops, the heater 19 is energized to preheat the hot water and maintain the water temperature in the tank at a predetermined temperature.

On the other hand, if the temperature near the tap outlet and the temperature near the water inlet are both higher than the set temperature, power to the heater 19 is cut off, and the temperature of the hot water in the tank decreases.

Therefore, the temperature of the hot water in the tank is controlled so that its temperature matches the set temperature.

At this time, adjustment of the set temperature in the first temperature sensor and the second temperature sensor is performed using the variable resistor 11.
It is carried out by. When the resistance value of the variable resistor 11 is changed, the resistance ratio between the combined resistance of the variable resistor 11 and the resistor 12 and the low resistance resistor 13 is changed, and the reference potentials at the two points are changed. The reference potentials at the two points are the negative input terminal of the voltage comparison IC 5 to which the detection voltage from the negative characteristic thermistor 2 which is the first temperature sensor is supplied, and the detection voltage from the negative characteristic thermistor 14 which is the second temperature sensor. - of voltage comparison IC9 to which voltage is supplied
Since it is commonly supplied to the side input terminals, the set temperature can be changed at the same time.

Now, one feature of the present invention is that the temperature control circuit is configured so that the set temperature is the highest when the resistance value of the variable resistor 11 is minimized.

In the present invention, when the resistance value of the variable resistor 11 is decreased, the reference potentials at the two points are increased. Since this reference potential corresponds to the set temperature, the temperature control circuit operates to increase the temperature of the hot water in the tank.

At this time, even if there is a tolerance in the resistance value of the variable resistor 11, the resistance value of the variable resistor 11 becomes 0 when the set temperature is set to the maximum temperature. Therefore, the tolerance of the resistance value of the variable resistor 11 does not affect the set temperature on the high temperature side. That is, the tolerance of the resistance value of the variable resistor 11 is expressed as the product of the resistance value and the tolerance, and the resistance value of the variable resistor 11 is 0.
When , the tolerance also becomes 0.

Therefore, the temperature on the highest temperature side, which requires the most precise temperature control, can be accurately controlled without error. As a result, there is no risk of hot water being discharged at a high temperature that would adversely affect the user's body, contrary to the user's intention.

Note that the set temperature range for temperature control based on the output of the first temperature sensor can be changed by adjusting the resistance ratio between the resistance value change width of the negative characteristic thermistor 2 and the resistance value of the resistor 3. On the other hand, the set temperature range for temperature control based on the output of the second temperature sensor can also be changed by adjusting the resistance ratio between the resistance value change width of the negative characteristic thermistor 14 and the resistance value of the resistor 15. can.

〔Effect of the invention〕

As explained above, when using the cleaning device of the present invention, in the cleaning device equipped with a feed water heater that has the function of maintaining the feed water temperature constant, when the set temperature of the feed water heater is set to the maximum, the temperature setting Temperature control can be performed with high precision without being affected by the tolerance of the variable resistor. Therefore, it is possible to reliably prevent high-temperature hot water from being discharged, which has an adverse effect on the human body, such as causing burns. As described above, the present invention has a great effect on improving the safety function of sanitary cleaning equipment.

[Brief explanation of the drawing]

The figure shows an example of a temperature control circuit attached to the feed water heater in the cleaning device of the present invention.

Claims (1)

[Claims] 1. Set by a heating unit that heats water in a hot water storage tank, a temperature detection unit installed in the hot water storage tank, a signal from the temperature detection unit, and a variable resistor for setting the hot water temperature. In a cleaning device equipped with a water supply heater comprising a temperature control unit that controls the heating unit so that the temperature of the hot water in the hot water storage tank is always maintained within an optimum temperature range by comparing the temperature with a reference potential, the power supply voltage The variable resistor, which divides the voltage and inputs the reference potential to the comparator, is connected in series with a fixed resistor, and when the resistance value of the variable resistor decreases, the temperature of the hot water in the hot water tank increases. A cleaning device equipped with a feed water heater, characterized in that the temperature control section is configured so that the temperature increases.