JPS6115016A - Controlling system of hot-water supplier - Google Patents

Abstract

PURPOSE:To prevent non-uniform temprature in hot-water to be supplied, by providing a circuit which forcibly makes a burner burn for a predetermined time when supplying of hot-water is started again, even if the temperature in water near a thermistor has been raised to a set temperature. CONSTITUTION:A method of control to obtain a predetermined uniform temperature in hot-water to be supplied is as follows, after the water temperature near a thermistor 6 exceeds a set temperature (T2), and a burner 4 ceases burning after a burner 5 has stopped burning, and supplying of hot-water is once stopped, and is started again after a certain time has passed. When supplying of hot- water is started again at the time (t1), decoders 73a and 73b output signals based on the counted values (m1) and (m2), respectively, and high level signals are output from a processing circuit 74 from a counting time (m1) to a counting time (m2). As a result, signals are fed into solenoid-operated valves 31 and 41 through AND gates 35 and 45, respectively, and the burner 4 burns as long as a time (t) only. By this method, a sandwiched conditio of hot-water by cold water can be prevented, and ununiform distribution of water temperature in a heat exchanger can be dissolved.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a control device for an instantaneous water heater.

[Prior art]

Figure 4 shows the schematic structure of the instant water heater. In the figure,
A fin-type heat exchanger 2 is arranged in the upper part of the combustion cylinder 1, and three gun-type burners 3, 4.5 are usually arranged in the lower part. Flow sensor 2 is installed in the water supply piping to heat exchanger 2.
1 is provided, and a thermistor 6 as a water temperature sensor is provided in the water piping of the main body of the heat exchanger 2 in the middle thereof. Solenoid valves 31 and 41 are installed in the oil supply pipes of burners 3 and 4.5.
.

51 are provided respectively. Signals from the thermistor 6° flow sensor 21, etc. are sent to the control circuit 7. The control circuit 7 operates the solenoid valves 31 and 41 based on these signals.
．． In addition to controlling the opening and closing of 51.

The combustion blower 82 controls the ignition device (not shown) and the like.

This water heater can supply hot water only while a signal is being sent from the flow sensor 21. Namely.

Solenoid valves 31, 41. Flow sensor 21 to open '51
Requires a signal from When the flow of water in the water supply pipe is detected, gunners 3 and 4.5 are ignited.

The water passing through the heat exchanger 2 is not heated, but instead becomes hot water and is supplied to a predetermined location from the hot water piping. The water temperature is maintained at the set temperature by controlling the ignition and extinguishing of the burner 3°4.5. Of course, this set temperature is variable.

[Problem that the invention seeks to solve]

By the way, in this type of instantaneous water heater, there is a phenomenon in which after the hot water supply is stopped once and hot water at an appropriate temperature is dispensed when hot water is re-supplied, cold water is dispensed for a short period of time, and then the temperature returns to the appropriate temperature. This phenomenon is due to the creation of a cold water sandwich within the heat exchanger, 2. This will be explained with reference to FIGS. 5(a) to 5(,).

In FIG. 5 (,), since appropriate combustion control is being performed while hot water supply continues, hot water at an appropriate temperature is flowing out.

When hot water supply is stopped in FIG. 5(b), combustion is immediately stopped by a signal from the flow sensor.

When the hot water supply is resumed several seconds to several minutes after the hot water supply is stopped, the remaining hot water is supplied as shown in Fig. 5(c), but combustion does not occur until the water supplied from the water supply pipe reaches the area around the thermistor 6. It remains stopped.

In FIG. 5(d), when the low-temperature supply water reaches the vicinity of the thermistor 3, combustion resumes.

In FIG. 5 (,), even if combustion starts, some of the water in the heat exchanger comes out of the hot water tap piping without increasing its temperature.

The present invention aims to provide a control device for a water heater that solves the problem of unstable hot water supply temperature as described above.

[Means for solving problems]

The present invention is characterized by the addition of a circuit that forcibly performs combustion for a predetermined period of time when hot water supply is restarted even when the water temperature near the water temperature sensor has risen to the set temperature and no ignition signal is output. Namely.

It includes a circuit that detects the amount of water supplied from the start of water supply using a signal from the flow sensor, and a circuit that detects the flow rate. A circuit is provided that performs combustion using an amount of heat depending on the flow rate only from the tenth water supply amount to the second water supply amount.

〔Example〕

The present invention will be explained in detail below.

FIG. 1 is a block diagram of one embodiment of the present invention.

A case where the present invention is applied to the water heater shown in FIG. 4 will be explained. Therefore, the same parts as in FIG. 4 are designated by the same reference numerals.

Solenoid valves 31, 41.51 are provided in the fuel oil supply pipes to the burners 3, 4.5, respectively. Also.

A thermistor 6 for detecting water temperature is provided in the intermediate piping of the heat exchanger. The solenoid valve 31 is controlled by the output of a comparator 32 which receives a signal from the temperature setting device 33 and a signal from the thermistor 6 as input. The solenoid valve 41 has a comparator 4 which receives a signal from the temperature setting device 43 and a signal from the thermistor 6 as input.
Similarly, the solenoid valve 51 is controlled by the output of the comparator 52. Note that, as described above, between the comparators and the electromagnetic valves, there are provided the AND/GO valves 34, 44, and 54, each of which receives a water flow signal generated from the signal from the flow sensor 21 as one of its inputs.

Therefore, unless water is being supplied from the water piping, or in other words, hot water is not being supplied from the hot water piping, the solenoid valve will not open, and if the hot water supply is stopped during combustion, the fire will be automatically extinguished.

In the control system of the solenoid valve 31, the first temperature set by the temperature setting device 33 is
The signal corresponding to the zero set temperature T1 is compared with the water temperature detection signal obtained from the thermistor 6, and if the set temperature TI is higher, the solenoid valve 31 is opened to continue combustion. and,
When the water temperature around the thermistor 6 reaches close to the set temperature,
The solenoid valve 31 is closed to extinguish the fire.

In the control system of the electromagnetic valve 41, the second set temperature T2 of the temperature setter 43 is lowered by a few degrees Celsius to several tens of degrees Celsius than the set value TI of the temperature setter 33.

Furthermore, in the control system of the solenoid valve 5J, the third temperature setting device 53
The set temperature T3 is set several degrees Celsius to several tens of degrees Celsius lower than the set temperature T2.

Therefore, according to this device, when water is supplied, both burners 3 and 4.5 are ignited and combustion begins.

When the water temperature in the heat exchanger rises and reaches the third set temperature T3, the burner 5 is extinguished, and when the water temperature reaches the second set temperature T2, the burner 4 is extinguished. Furthermore, when the temperature rises and reaches the tenth set temperature TtK, the burner 3 is also extinguished.

The present invention is characterized in that this device is further provided with one forced combustion circuit. This circuit is a circuit that uses a signal from the flow sensor 21 to perform combustion according to the flow velocity regardless of the output of the AND gates 34, 44, and 54.

Here, the flow sensor 21 has a rotor 2 whose rotational speed changes in proportion to the flow velocity, as shown in FIG.
11 is detected by a sensor 212, and a pulse signal is generated in which the number of pulses per unit time is proportional to the flow velocity.

The forced combustion circuit starts counting the signal from the flow sensor 21 at the start of water supply using the counter 72a and the decoder 73a, and sends out a signal when it reaches a predetermined value. 10 A circuit for detecting the water supply amount, a circuit for similarly detecting a second water supply amount predetermined by the counter 26 and a decoder 36, and a solenoid valve 31, 41 using the output of these two water supply amount detection circuits. .51 Arithmetic circuit 7 that creates opening/closing signals
4 and 2 frequency-voltage converter 75 and comparator 76°77.7
8, the flow rate of water supply is predetermined as high, medium,
and a circuit for detecting which range of the small range it belongs to.

The solenoid valves 31, 41.51 are each connected to an AND gate 34.
．． In addition to the output of 44.54, and dart 35°45.
It is configured so that it can be opened and closed even with an output of 55.

That is, the output of the arithmetic circuit 74 and the output of the comparator 78 for low flow velocity detection are input to the AND gate 35.

Further, the output of the arithmetic circuit 74 and the output of the comparator 77 for medium flow velocity detection are input to the AND gate 45, and the output of the arithmetic circuit 74 and the output of the comparator 76 for high flow velocity detection are input to the AND gate 55. ing.

Next, the operation will be explained with reference to FIG. 3 showing input/output signal waveforms of each part.

In this circuit, at the same time that hot water supply starts, a pulse signal from the fo sensor 21 is sent to the counter 72a.

72b.

Period a+b in FIG. 3 is a waveform chart showing the transition of hot water supply when the water in the heat exchanger is in a low temperature state.

Counter 72a, ? 2b counts incoming pulse signals, and decoders 73a and 73b output a signal at a predetermined count value ml+m2 (m2).

The arithmetic circuit 74 outputs a high level signal from the time when the decoder 73a counts the town until the time when the decoder 73b counts m2. On the other hand, if the water supply during this period is 8, for example, at a medium flow rate, the comparators 77, 78 output a level signal, and this causes the solenoid valve 31, 41 to be supplied for the time t specified by the output of the arithmetic circuit 74. A signal to open is sent. However, at this time, the solenoid valve 31.
Since the combustion signal is being sent from 4.44, the signal is invalid.

Andgoo) 34. Burns by a signal based on 44.

Surpassed. If the flow rate of the water supply is low, only the comparator 78 outputs a high level signal, and a signal is sent only to the solenoid valve 31 attached to the burner 3. However, even in this case, the burner 3 receives the signal from the AND gate 34. Burn based on.

Referring to period b + c in Figure 3, when the water temperature around the thermistor 6 exceeds the set temperature T2 and burner 4 is extinguished following burner 5, hot water supply is stopped and hot water supply is restarted for a certain period of time. I will explain about it. When hot water supply is restarted at time tl, the decoders 73g and 73b each have a count value of +m.
2, and the arithmetic circuit 74 outputs an irregular signal from m1 counting to m2 counting. As a result, the solenoid valve 31.
A signal is sent to 41 and burner 4 burns for a time t.

Note that the second burner 3 burns based on the signal from the AND gate 34. Therefore, in this case, the forced combustion of the burner 4) prevents the cold water sandwich phenomenon, and also causes the uneven temperature distribution inside the heat exchanger, which conventionally occurs, as shown by the broken line in Figure 3. It disappears.

It goes without saying that the counts of the counters 72a and 72b correspond to the amount of water supplied. And decoders 73a, 7
ml r ml set in 3b is calculated by taking into account the water capacity of the heat exchanger 2. Normally, in a town, the water capacity μ corresponds to the water supply amount + mfi is a value corresponding to the water supply amount that is almost equal to the water capacity. is set to

In addition, in the example, three burners were used for ignition.

Although a device for switching exothermic food in three stages by extinguishing has been described, the present invention can be applied not only to control of ignition and extinguishing using one burner, but also to control of switching using two or four or more burners.

〔Effect of the invention〕

As explained above, one feature of the present invention is that the cold water sandwich phenomenon in the heat exchanger when hot water supply is resumed can be prevented regardless of the amount of hot water supply, and as a result, the hot water supply does not have the drawback of temporary cold water coming out. We can provide equipment.

[Brief explanation of drawings]

Fig. 1 is a block diagram of an embodiment of the present invention, Fig. 2 is a sectional view of a flow sensor therein, and Fig. 3 shows changes in water temperature in the heat exchanger and input/output signal waveforms of each part in Fig. 1. A time chart diagram, FIG. 4 is a schematic configuration diagram of a water heater to which the present invention is applied,
FIGS. 5(,) to 5(,) are diagrams for explaining the drawbacks of conventional example Q. In the figure, 1 is a combustion tube, 2 is a heat exchanger, and 3 and 4.5 are burners.

Claims (1)

[Claims] 1. Combustion control for ignition and extinguishment according to the difference between the detected water temperature and the set temperature while hot water is being supplied, using the signal from the water temperature sensor installed in the middle of the water pipe of the heat exchanger. The water piping is provided with a flow sensor, and the apparatus includes a circuit for detecting the amount of water supplied from the start of water supply and a circuit for detecting the flow velocity based on a signal from the flow sensor, and a circuit for detecting the flow rate from the start of water supply. 1. A control device for a water heater, comprising a circuit that forcibly performs combustion with an amount of heat according to the flow rate from when a second amount of water is detected to when a second amount of water is detected.