JPS6143618B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a water boiling device used in a supply machine for supplying tea, black tea, and the like.

Conventionally, in tea dispensers and the like, a heater provided in a water tank is controlled by a thermostat to maintain the water temperature in the tank within a specified temperature range. On the other hand, in tea dispensers and the like, it is necessary to display an appropriate temperature for the convenience of the user, and to provide a device to prevent excessive temperature rise in the event of safety concerns.

However, since these operating temperature settings are different from each other, the above-mentioned water temperature control thermostat alone cannot handle the various functions mentioned above, so a separate thermostat and temperature detection element corresponding to each operating temperature setting is required. I had to.

The object of the present invention is to use one temperature detection element,
It is an object of the present invention to provide a water heating device that can handle various functions such as appropriate temperature display and abnormality display in addition to water temperature control by analyzing changes in output signals corresponding to temperature changes.

The water heating device of the present invention includes a tank that stores water, a heater that heats the water in the tank,
A heater control circuit that controls the energization state of the heater, a plurality of indicators that display the water temperature in the tank including an appropriate temperature display and an abnormal display, and a temperature detection element that detects the water temperature in the tank. An oscillation circuit that operates with the output signal of the temperature detection element as input and generates output pulses with different frequencies in proportion to the output signal, and the output pulses of this oscillation circuit are counted and compared with a pre-stored reference pulse number value. The apparatus further includes a signal control circuit that drives the heater control circuit and operates each of the indicators according to the deviation value.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

In Fig. 1, 11 is a tank, and water supply pipe 12
This water is heated by a heater 13 provided in the tank 11 to reach a predetermined temperature, and then hot water is supplied by opening the hot water supply valve 17 of the hot water supply pipe 14. In this embodiment, a case is shown in which the hot water is used in a tea dispenser, and the hot water is supplied as tea to a cup 16 via a tea strainer 15.

18 is a temperature detection element that produces an output corresponding to the water temperature in the tank 11. As this temperature detection element 18, for example, a negative resistance element (thermistor) whose resistance value decreases as the temperature rises is used. 19
is an oscillation circuit which operates with the output signal of the temperature detection element 18 as input, and generates output pulses with different frequencies in proportion to the output. For example, when the water temperature rises and the resistance of the temperature detection element 18 decreases,
The oscillation frequency becomes faster.

21 is a signal control circuit using, for example, a microcomputer. This signal control circuit 21
Although not shown, there are a digital input section that receives output pulses from the oscillation circuit 19, a storage section that stores a predetermined control program and reference pulse numbers for various operation settings described later as data, and the control program. Accordingly, it has a central processing unit (hereinafter referred to as CPU) that performs arithmetic processing based on stored data and input data, and a digital output unit that outputs the results obtained by the CPU to each device described later. 23
2 is a heater control circuit which outputs various output signals generated by the signal control circuit 21, that is, water temperature control signals a, b, and which are output to control the water temperature within the range of temperatures B and C, as shown in FIG. Upon receiving the signal c for preventing excessive temperature rise that occurs when the water temperature reaches temperature A, the power supply to the heater 13 is turned on and off in accordance with these signals.
Control off.

Reference numerals 24, 25, and 26 indicate a plurality of indicators for displaying water temperature conditions and abnormal conditions in the tank 11, 24 an appropriate temperature indicator 25 for indicating that the water temperature has exceeded temperature 2 in FIG. 26 is a digital temperature indicator that displays the water temperature in decimal notation, and 26 is an abnormality indicator that indicates that an abnormality has occurred such as a failure of the temperature detection element 18. These are the signals d from the signal control circuit 21. , e, f.

In the above configuration, the signal control circuit 21 receives and counts output pulses generated by the oscillation circuit 19. As mentioned above, the oscillation frequency by the oscillation circuit 19 changes as a function of the water temperature in the tank 11. For example, if the water temperature rises, the number of oscillation pulses per unit time increases in proportion to this, and the signal control The count value in circuit 21 also increases. Signal control circuit 2
1, the CPU compares this counted value with a pre-stored reference pulse number value at regular intervals according to a predetermined control program, and calculates the deviation value.
That is, if this count value is the number of pulses corresponding to temperature d in FIG. 2, a signal d for indicating the appropriate temperature is generated, the appropriate temperature display 24 is operated, and the appropriate temperature is displayed. Further, if the number of pulses is greater than or equal to the temperature B in FIG. 2, a signal a is given to the heater control circuit 23,
The power to the heater 13 is cut off. On the other hand, if the number of pulses is less than the number of pulses corresponding to temperature C in FIG. Furthermore, when the number of pulses exceeds the temperature corresponding to temperature A in FIG. Cut off the power to. Next, this count value is converted into a signal e for display in decimal notation and is applied to the digital temperature display 25, which numerically displays the current value of the water temperature. On the other hand, if the temperature detection element 18 fails and its resistance value becomes zero or infinite, the number of pulses generated by the oscillation circuit 19 per unit time will also vary accordingly. Therefore, since the pre-stored upper and lower limit values are exceeded, it is determined that an abnormality has occurred in this case, and an abnormality display signal f is generated to operate the abnormality indicator 26.

In this way, by analyzing the output of one temperature detection element 18, various functions can be satisfied.

In the above embodiment, a negative resistance element is used as the temperature detection element 18, but a thermocouple may be used for similar control using its thermal electromotive force. Various other thermoelectric conversion elements can be used, such as those whose magnetization retention changes with heat or those whose dielectric constant changes. In addition, if a microcomputer is not used as the signal control circuit 21, a level detection circuit using the base voltage displacement of the transistor is used.
A relay or the like may be operated by the output.

As described above, according to the present invention, by analyzing the output signal of one temperature detection element as a function of frequency, it is possible to handle all of the various functions such as water temperature control, appropriate temperature display, abnormality display, etc. It is simpler than the case where temperature detection elements and related control circuits are provided for each function.
Moreover, accurate control can be performed.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a water heating apparatus according to the present invention, and FIG. 2 is a graph showing the relationship between water temperature changes and control signals in the apparatus according to the present invention. 11... Tank, 13... Heater, 18... Temperature detection element, 19... Oscillation circuit, 21... Signal control circuit, 23... Heater control circuit, 24... Appropriate temperature indicator, 25... Digital temperature display Vessel, 26...
...Abnormality indicator.

Claims (1)

[Claims] 1. A tank containing water, a heater that heats the water in the tank, a heater control circuit that controls the energization state of the heater, and an appropriate temperature display and abnormality display for the water temperature in the tank. a temperature detection element that detects the water temperature in the tank; and a temperature detection element that operates with the output signal of this temperature detection element as input and generates output pulses with different frequencies in proportion to the output signal. and a signal control circuit that counts the output pulses of this oscillation circuit, compares them with a pre-stored reference pulse number value, and drives the heater control circuit and operates each of the indicators according to the deviation value. A water heating device characterized by comprising the following.