JP2019045085A - Water heater - Google Patents

Abstract

To eliminate the possibility that high-temperature hot water in an apparatus may be delivered even when a safety device for boiling without water is actuated.SOLUTION: When a determination that hot water supply combustion is being performed is made in S1, whether or not a detection temperature from a water pipe thermistor provided in a hot water supply heat exchanger exceeds 110°C is determined in S2. When exceeding 110°C is confirmed, a controller prohibits combustion of a burner and indicates an abnormality on a hot water supply remote controller and a bath remote controller in S3. At the same time, an instruction is issued to cause a distribution valve of a bypass pipe to become in a fully open position so as to supply all water from the bypass pipe to a hot water delivery pipe. Due to this, the water from the bypass pipe can be mixed with high-temperature hot water retaining in the hot water supply heat exchanger. When a state where the distribution valve is in the fully open position is confirmed in S4, an instruction is issued to cause a water amount control valve to become in a fully close position so as to minimize a flow rate from the hot water delivery pipe in S5.SELECTED DRAWING: Figure 2

Description

  According to the present invention, a bypass pipe for bypassing the heat exchanger is connected between the water supply pipe connected to the heat exchanger and the hot water discharge pipe, and the flow rate of the bypass pipe is controlled to output the hot water temperature from the heat exchanger. It relates to the adjustable water heater.

In the water heater, the water supply pipe and the hot water discharge pipe are connected to the heat exchanger heated to the burner, and the bypass pipe is connected between the water supply pipe and the hot water discharge pipe. By variably controlling with the operating distribution valve, the hot water temperature (outlet temperature) from the heat exchanger is maintained above a predetermined temperature to prevent the generation of drain, and in the case of high temperature hot water, the flow path of the bypass pipe is It is known to prevent overheating of the heat exchanger by closing it.
In such a water heater, although the water is not actually supplied to the heat exchanger due to a failure of the water quantity sensor provided in the water supply pipe or a partial freezing of the pipe connected to the heat exchanger, the burner As the heat exchanger may be heated and the heat exchanger may be heated, the water in the heat exchanger is superheated and boils. In order to detect the open state and stop the appliance, for example, as disclosed in Patent Document 1, when the detected hot water temperature is detected to be higher than the set temperature by a predetermined value or more, the hot water discharge pipe Measures to stop the hot water supply by closing the control valve of

Unexamined-Japanese-Patent No. 10-89771

  However, even if the hot water is stopped by such an open-loop safety device, the hot water may stay in the appliance even when the user opens the hot water tap. There was a risk of being discharged.

  Therefore, an object of the present invention is to provide a water heater in which there is no risk of the hot water in the appliance being discharged even if the dry air safety device is activated.

In order to achieve the above object, the invention according to claim 1 is connected to a burner, a heat exchanger through which the combustion exhaust of the burner passes, a feed pipe connected to the heat exchanger, and a heat exchanger A hot water discharge pipe, a bypass pipe connected between the water supply pipe and the hot water discharge pipe to bypass the heat exchanger, a bypass flow control means for controlling the flow rate of the bypass pipe, and the temperature of hot and cold water in the heat exchanger The heat exchanger temperature detection means and the burner combustion and bypass flow rate control means are controlled, and when the temperature detected by the heat exchanger temperature detection means exceeds a predetermined temperature during the burner combustion, the burner combustion is prohibited. A water heater having a controller capable of executing dry heating safety control;
The controller is characterized in that the flow rate of the bypass pipe is changed to the increase side by the bypass flow rate control means when executing the dry air safety control.
The invention according to claim 2 is characterized in that, in the configuration according to claim 1, the hot-water outlet flow rate control means for controlling the flow rate of the hot-water outlet pipe, the controller changes the flow rate of the bypass pipe to the increase side It is characterized in that the flow rate of the outlet pipe is changed to the reduction side.

According to the first aspect of the invention, the flow rate of the bypass pipe is increased when the hot water is generated, so that the hot water in the device can be mixed with the water from the bypass pipe to lower the outlet temperature. Therefore, even if the open-air safety device is activated, there is no risk of the hot water in the device being released.
According to the invention of claim 2, in addition to the effect of claim 1, the flow rate of the outlet pipe is changed to the decrease side after changing the flow rate of the bypass pipe to the increase side. Even then, the hot water in the device will not be flushed out vigorously.

It is a schematic circuit diagram of a water heater. It is a flowchart of dry air safety control.

Hereinafter, embodiments of the present invention will be described based on the drawings.
FIG. 1 is a schematic circuit diagram showing an example of a water heater. This water heater 1 supplies combustion air to each burner unit 3 and three burner units 3, 3... Provided with a plurality of burners 4, 4. In the upper part in the combustion chamber 2, a hot water supply heat exchanger 6 and a bath heat exchanger 7 through which the combustion exhausts of the burners 4, 4... Pass are juxtaposed. 8 is a spark plug, 9 is a flame rod, and an exhaust hood 10 for exhausting the combustion exhaust gas passing through both heat exchangers 6, 7 is provided at the upper part of the combustion chamber 2. A sheet-like overheat protection device 11 printed with a fuse circuit for detecting leakage of combustion exhaust gas from the chamber 2 is wound.

  A gas pipe 12 to which a gas pipe from the outside is connected is connected to a gas inlet of a device accommodating the combustion chamber 2 and the like, and each burner unit 3 is connected to branch pipes 13, 13 · · · branched from the gas pipe 12 Are connected to each other, and each branch pipe 13 is provided with a gas solenoid valve 14 for opening and closing a gas flow path. Further, in the gas pipe 12 before branching, a source gas solenoid valve 15 and a gas proportional valve 16 are provided from the upstream side.

The hot water supply heat exchanger 6 includes a hot water supply heat transfer pipe 18 penetrating the plurality of fins 17, 17 ··· arranged at a predetermined interval in a serpentine manner, and the inlet of the hot water supply heat transfer pipe 18 is a water inlet of an appliance. The water supply pipe 19 connected to is connected, and the outlet pipe 20 connected to the hot water outlet of the appliance is connected to the outlet of the hot water supply heat transfer pipe 18. A water tube thermistor 21 as heat exchanger temperature detection means for detecting the temperature of the hot water supply heat transfer pipe 18 is provided at a bent portion of the hot water supply heat transfer pipe 18 exposed to the outside of the hot water supply heat exchanger 6. Further, a bypass pipe 22 bypassing the hot water supply heat exchanger 6 is connected between the water supply pipe 19 and the hot water discharge pipe 20, and a connection portion between the water supply pipe 19 and the bypass pipe 22 is driven by a stepping motor. A distribution valve 23 is provided as bypass flow rate control means for variably controlling the flow rate of the bypass pipe 22.
There is.

Further, on the upstream side of the connection portion of the water supply pipe 19 with the bypass pipe 22, a water inlet thermistor 24 for detecting the temperature of the incoming water and a hot water supply sensor 25 for detecting the amount of water flowing through the water supply pipe 19 are provided.
Then, at the outlet of the hot water supply heat exchanger 6 in the hot water discharge pipe 20, a hot water supply heat exchanger thermistor 26 for detecting the outlet temperature is provided, and the hot water discharge temperature is detected downstream of the connection portion with the bypass pipe 22 A hot water discharge hot water thermistor 27 and a water flow control valve 28 as a hot water discharge flow control means which is driven by a stepping motor to variably control the flow rate of the hot water discharge pipe 20 are provided.

  On the other hand, the bath heat exchanger 7 includes a bath heat transfer pipe 30 penetrating the fins 17 17 in a meandering manner, and the bath adapter 32 of the external bath 31 at the inlet of the bath heat transfer pipe 30 via external piping. The bath return pipe 33 connected is connected to the outlet of the bath heat transfer pipe 30, and the bath return pipe 34 connected to the bath adapter 32 via an external pipe is connected. A pump 35 is provided in the bath return pipe 33, and a bath return thermistor 36 for detecting a bath return temperature is provided on the upstream side thereof, and a hot water in the bath return pipe 33 is provided on the downstream side of the pump 35. A bath water flow switch 37 which is turned ON / OFF by the flow and a water level sensor 38 which detects the water level in the bath 31 by water pressure are provided. Further, a bath-tripping thermistor 34 is provided in the bath-passing pipe 34 for detecting the bath-passing temperature.

Further, a drop-in pipe 41 is connected to the downstream side of the water amount control valve 28 in the tapping pipe 20 and between the pump 35 and the bath return thermistor 36 in the bath return pipe 33. A bath water amount sensor 42 for detecting the amount of water flowing in the dropping 41 is provided on the upstream side of the dropping pipe 41, and a dropping water solenoid valve 43 for opening and closing the dropping pipe 41 is provided on the downstream side. Furthermore, two check valves 44, 44 are provided on the downstream side of the dropping water solenoid valve 43, respectively, and between the check valves 44, 44, the hot and cold water flowing back from the bath return pipe 33 is A discharge valve 45 is connected.
Reference numeral 50 denotes a controller that receives detection signals from the thermistors, sensors, etc., operates the valves, etc., and performs hot water temperature control, pouring control to the bathtub 31, etc. 51 is a hot water supply remote control, and 52 is a bath remote control.

In the water heater 1 configured as described above, first, normal hot water supply is performed as follows.
The hot water supply tap of the external piping connected to the hot water outlet is opened and water flows in the device, and when the water flow is detected by the hot water supply amount sensor 25, the controller 50 rotates the combustion fan 5 for a predetermined time to burn The combustion exhaust stored in the chamber 2 is discharged (prepurge). Thereafter, the source gas solenoid valve 15 of the gas pipe 12 and each gas solenoid valve 14 are opened, the gas proportional valve 16 is opened at a predetermined opening degree, gas is supplied to each burner unit 3, and the igniter is operated. The burner 4, 4,... Is ignited by the spark plug 8.
Thereby, in the hot water supply heat exchanger 6, the water flowing through the hot water supply heat transfer pipe 18 is heat-exchanged with the combustion exhaust of the burner 4, and the heated hot water is discharged from the hot water supply tap through the hot water discharge pipe 20 and the external piping.

The controller 50 monitors the outlet temperature by the hot water supply heat exchanger thermistor 26 of the hot water discharge pipe 20, and drives the stepping motor of the distribution valve 23, and the outlet temperature prevents the generation and overheating of the drain in the hot water supply heat exchanger 6. The flow rate (bypass rate) to the bypass pipe 22 is controlled so as to be maintained within the possible temperature range.
Still, the hot water discharge temperature is monitored by the hot water discharge hot water thermistor 27, and the open / close control of each gas solenoid valve 14 and the open of the gas proportional valve 16 so that the hot water discharge temperature becomes the set temperature instructed by the hot water supply remote control 51 or the bath remote control 52. The air amount is continuously changed by controlling the rotational speed of the combustion fan 5 while performing the power adjustment.
When the hot water supply plug is closed, the controller 50 that has confirmed the stop of the signal from the hot water supply amount sensor 25 closes the original gas solenoid valve 15 and the gas solenoid valve 14 to extinguish the burner 4 and rotates the combustion fan 5 for a predetermined time (post purge).

On the other hand, when the automatic switch of the hot water supply remote control 51 or the bath remote control 52 is pressed, the controller 50 opens the drop water electromagnetic valve 43 of the drop pipe 41 to cause the hot water supply heat exchanger 6 to flow water to burn the burner 4. Hot water from the hot water discharge pipe 20 is supplied to the bath 31 through the drop-in pipe 41 and the bath return pipe 33. When the water amount detected by the bath water amount sensor 42 provided in the dropping pipe 41 reaches the set water amount, the dropping water solenoid valve 43 is closed to stop the water flow, and the burner 4 is extinguished.
Next, the pump 35 is operated to circulate hot water between the bath heat exchanger 7 and the bath 31. At this time, if the temperature of the hot water circulating is monitored by the bath return thermistor 36 and the bath going thermistor 36 and it is confirmed that the temperature from the set temperature is lowered, the burners 4, 4. Combustion air is supplied by the fan 5. Therefore, when the bath circulating water circulating between the bath heat exchanger 7 and the bath 31 flows through the bath heat transfer pipe 30, it is heat-exchanged with the combustion exhaust of the burner 4 and heated to the set temperature. When the set temperature is reached, the combustion of the burner 4 is stopped and the pump 35 is stopped.

Then, the controller 50 monitors the temperature detected by the water pipe thermistor 21 during hot water supply combustion using the hot water supply heat exchanger 6, and performs an open flame in which the burner 4 burns without passing through the hot water supply heat exchanger 6. When detected, it is possible to execute an air-plow safety control that stops the combustion of the burner 4 and prohibits the subsequent use. This blanking safety control will be described based on the flowchart of FIG.
First, at S1, the controller 50 determines whether hot water supply combustion is in progress. The confirmation of the operation state is performed by detecting the flame current from the frame rod 9 provided in the burner 4 or the like.

  Here, if hot-water supply combustion is in progress, it is determined in S2 whether the temperature detected from the water tube thermistor 21 exceeds 110 ° C. The reason is that the burner 4 burns without water flowing into the hot water supply heat exchanger 6 due to a failure of the hot water detection sensor 25, a freezing of the water supply pipe 19 or the hot water discharge pipe 20, an open failure of the gas solenoid valve 14 or the like. If done, the hot water supply heat transfer pipe 18 is heated to 110 ° C. to 120 ° C., so if the temperature detected by the water pipe thermistor 21 exceeds 110 ° C., it can be determined that a dry-up has occurred.

Therefore, when it is confirmed in S2 that the temperature exceeds 110 ° C., in S3, the controller 50 closes the source gas solenoid valve 15 and the gas solenoid valve 14 to extinguish the burner 4 to prohibit the subsequent combustion, An abnormality display is performed on the hot water supply remote control 51 and the bath remote control 52. At the same time, the stepping motor is instructed to bring the distribution valve 23 to the fully open position to supply all the water from the bypass pipe 22 to the hot water outlet pipe 20. Thus, the hot water accumulated in the hot water supply heat exchanger 6 can be mixed with the water passing through the bypass pipe 22.
When it is confirmed in S4 that the distribution valve 23 is in the fully open position, in S5, the controller 50 instructs the water quantity control valve 28 to be in the fully closed position. As a result, the flow rate from the hot water discharge pipe 20 is minimized, and it is not possible to force the hot water supply tap to discharge hot water.

As described above, according to the water heater 1 of the above-described embodiment, the controller 50 maximizes the flow rate of the bypass pipe 22 by the distribution valve 23 when executing the dry-air safety control, and therefore when dry-air occurs. The hot water in the device can be mixed with the water from the bypass pipe 22 to lower the hot water temperature. Therefore, even if the open-air safety device is activated, there is no risk of the hot water in the device being released.
Especially in this case, after the flow rate of the bypass pipe 22 is maximized, the flow rate of the hot water outlet pipe 20 is minimized by the water amount control valve 28. Therefore, even if the hot water supply tap is opened thereafter, the hot water in the appliance is vigorously discharged It will not be done.
Here, when only one drive circuit of the stepping motor is formed on the control board constituting the controller 50, if the distribution valve 23 and the water quantity control valve 28 are simultaneously driven, the movement of each valve will be delayed. . However, if the distribution valve 23 and the water amount control valve 28 are sequentially operated in this way, even if there is only one drive circuit, it is possible to rapidly mix the water into the hot water. Therefore, the controller 50 can be manufactured at low cost while securing safety.

In the above embodiment, when performing dry air safety control, the flow rate of the bypass pipe 22 is maximized by the distribution valve 23. However, the flow rate is not limited to the maximum. Less flow may be acceptable.
Similarly, after changing the flow rate of the bypass pipe 22 to the increase side, the flow rate of the hot water discharge pipe 20 is minimized by the water amount control valve 28. However, the flow rate is not limited to the minimum, The flow rate may be higher than the minimum. In addition, the minimum of the flow rate also includes 0 (fully closed).
However, it is not essential to provide both the bypass flow rate control means (distribution valve 23) and the hot water discharge flow rate control means (water amount control valve 28), even if the hot water flow rate control means is omitted and only the bypass flow rate control means is provided Hot water prevention is possible.

On the other hand, there may be a plurality of water tube thermistors serving as heat exchanger temperature detection means (in this case, it may be determined whether the average value of each detected temperature exceeds a predetermined temperature). Also in the judgment of (1), it may be judged as open-air at 110 ° C. or higher, and the detected temperature may be increased or decreased not limited to 110 ° C. The heat exchanger temperature detection means is not limited to the water tube thermistor, and a bimetal switch or the like may be employed.
In the above embodiment, although the hot water supply heat exchanger and the bath heat exchanger are combined in one combustion chamber, the hot water supply combustion chamber having the hot water supply heat exchanger and the bath heat exchanger are described. The water heater may be provided separately from the bath combustion chamber. In addition, a bath circuit connecting the bath heat exchanger and the bath is not essential, and the present invention can be applied to a water heater having only a hot water supply circuit consisting of a hot water supply heat exchanger, a water supply pipe, a hot water discharge pipe and a bypass pipe. It is applicable.
Furthermore, although the hot water discharge flow control means is provided with a water flow control valve in the hot water discharge pipe, even if the hot water supply flow control means such as a water flow control valve is provided in the water supply pipe, reduction control of the hot water discharge flow is possible.

  1 · · Water heater, 2 · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · combustion fan, 5 · · hot water heat exchanger, 7 · · bath heat exchanger, 12 · · gas pipe 18 · · · hot water heat transfer pipe, 19 · · water supply pipe, 20 · · hot water discharge pipe, 21 · · water pipe thermistor, 22 · · bypass pipe, 23 · · distribution valve, 24 · · incoming water thermistor, 25 · · hot water detection sensor , 28: water flow control valve, 30, 30: bath heat transfer pipe, 31: bath, 33: bath return pipe, 34: forward bath pipe, 41: drop pipe, 50: controller.

Claims (2)

With the burner,
A heat exchanger through which the combustion exhaust of the burner passes;
A water supply pipe connected to the heat exchanger;
A tapping pipe connected to the heat exchanger;
A bypass pipe connected between the water supply pipe and the tapping pipe to bypass the heat exchanger;
Bypass flow rate control means for controlling the flow rate of the bypass pipe;
Heat exchanger temperature detection means for detecting the temperature of hot and cold water in the heat exchanger;
An open-air safety that controls the combustion of the burner and the bypass flow control means, and prohibits the combustion of the burner when the temperature detected by the heat exchanger temperature detection means exceeds a predetermined temperature during the combustion of the burner And a controller capable of performing control, wherein the water heater comprises
A water heater, wherein the controller changes the flow rate of the bypass pipe to the increase side by the bypass flow rate control means when executing the open-air safety control.   The hot water discharge flow control means for controlling the flow rate of the hot water discharge pipe, the controller changes the flow rate of the bypass pipe to the increase side, and then changes the flow rate of the hot water discharge pipe to the decrease side by the hot water discharge flow control means. The water heater according to claim 1, characterized in that.

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