JP2016017709A - Water heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water heater capable of restricting a variation in temperature of hot water flowing at a downstream side of a hot water discharging passage by a simple and less-expensive structure.SOLUTION: This invention relates to a water heater 1 having a heat exchanger 2 for heating water supplied from a water supply passage 5 with combustion heat of a burner 3 and fed out to a hot water feeding passage 6. There is provided a bypass passage 10 having one end branched from an upstream side of the hot water feeding passage and the other end merged with the downstream side of the hot water feeding passage. Hot water is left at the bypass passage after stopping of hot water feeding at a previous time due to the fact that hot water flows from the upstream side of the hot water feeding passage by the hot water feeding at the previous time into the bypass passage, and in hot water feeding at a next time, the hot water left in the bypass passage and hot water flowing from the upstream side of a hot water feeding pipe to the downstream side of the hot water feeding pipe by hot water feeding at the next time are mixed to each other and the mixed hot water is flowed to the downstream side.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a water heater having a heat exchanger that heats water supplied from a water supply channel with combustion heat of a burner and discharges it to a hot water supply channel.

  For example, Patent Document 1 discloses a water heater that suppresses fluctuations in the hot water temperature during intermittent re-heating. The water heater in Patent Document 1 includes a heat exchanger that heats water supplied from a water supply channel by combustion heat of a burner and supplies the heat to a hot water channel, and bypasses the heat exchanger to connect the water supply channel and the hot water channel. A bypass path for communication and a bypass valve for opening and closing the bypass path are provided. In the water heater of Patent Document 1, when a post-boiling phenomenon occurs after the start of the hot water operation, the temperature of the hot water remaining in the heat exchanger rises. However, when the hot water tap is opened and the hot water discharge operation is started again, when a flow rate smaller than the ignition flow rate is detected, the controller opens the bypass valve at a timing earlier than the ignition flow. On the downstream side, mixed hot water in which hot water whose temperature has increased and water supplied from the bypass passage is mixed flows. Thereby, a bypass valve can be opened early and the rise in the temperature of the hot water flowing to the downstream side of the hot water outlet can be suppressed.

  In addition to the technique described in Patent Document 1, for example, a shape memory alloy spring whose spring constant changes depending on the temperature of hot water flowing through a tapping channel adjusts the opening of a bypass valve that opens and closes the bypass channel. An increase or decrease in the temperature of hot water flowing downstream of the hot water outlet is suppressed by increasing or decreasing the amount of water supplied from the bypass road to the hot water outlet.

Japanese Patent Laid-Open No. 10-19379

  However, as in the hot water heater described above, the controller controls the opening and closing of the bypass valve to suppress the rise of the hot water temperature on the downstream side of the hot water path, so that the hot water temperature detected by the temperature sensor is set to the target temperature. In order to approach, it was necessary for the controller to perform a plurality of controls including a control for continuously opening and closing the bypass valve. For this reason, there has been a demand for suppressing fluctuations in the temperature of hot water flowing downstream of the hot water outlet with a simple structure that does not require complicated control consisting of a plurality of controls. Furthermore, when the shape memory alloy spring as described above is used, the manufacturing cost of the hot water heater increases, and there has been a demand for suppressing fluctuations in the temperature of the hot water flowing downstream of the hot water outlet with an inexpensive structure. . In addition, when the ignition flow rate is suddenly reached, such as when the hot-water tap is opened greatly, there may be a problem that heated hot water is supplied before the bypass valve is opened. In order to prevent this, the amount of water needs to be supplied in two stages at the time of ignition, but it is useless because it is necessary to provide a separate throttle valve or the like.

  This invention is proposed in view of such a situation, and it aims at providing the hot water heater which can suppress the fluctuation | variation of the temperature of the hot water which flows into the downstream of a tapping channel with a simple and cheap structure. .

In order to achieve the above object, the invention described in claim 1 is a water heater having a heat exchanger that heats water supplied from a water supply channel by the combustion heat of a burner and discharges the water to a hot water channel. Is branched from the upstream side of the hot water outlet, and the other end has a detour that joins the downstream side of the hot water path, and the hot water has flowed into the detour from the upstream side of the hot water path due to the previous hot water, Hot water remains in the detour after the last stoppage of the hot water, and the hot water remaining in the detour and the hot water that flows from the upstream side of the tapping pipe to the downstream side of the tapping pipe by the next tapping. The mixed hot water is caused to flow downstream.
The invention described in claim 2 is characterized in that, in the configuration described in claim 1, a heat insulating material covering the outer periphery of the detour is provided.

According to the first aspect of the present invention, even if the temperature of the hot water upstream of the hot water outlet may increase due to a post-boiling phenomenon after the previous hot water stop, The mixed hot water in which the hot water whose temperature has increased and the hot water remaining in the detour by the previous hot water can be flowed to the downstream side. Thereby, the raise of the temperature of the hot water which flows into the downstream of a hot water path can be suppressed.
Further, since the burner ignites after the start of water flow to the water supply channel at the time of the next hot water discharge, heating of the water flow becomes insufficient. As a result, the water immediately after the ignition of the burner is not sufficiently heated. The hot water at a temperature lower than the target temperature may flow on the upstream side of the hot water outlet, but this hot water and the hot water remaining in the detour by the previous hot water are mixed on the downstream side of the hot water outlet. Hot water can be flown, and thereby a decrease in the temperature of hot water flowing downstream of the hot water outlet can be suppressed.
Therefore, fluctuations in the temperature of the hot water that flows downstream of the hot water channel (rise and decrease) with a simple and inexpensive structure that simply provides a detour in the hot water channel without complicated control by a conventional controller. Can be suppressed.
According to the second aspect of the present invention, since heat radiation from the detour can be suppressed by the heat insulating material, in particular, it remains in the detour after the stop of the last hot water, and from the target temperature at the time of the next hot water. Moreover, it can suppress that the temperature of the hot water mixed with low temperature hot water falls. As a result, it is possible to effectively suppress a decrease in the temperature of the hot water flowing downstream of the hot water discharge pipe in the next hot water discharge. In addition, if enough time has passed since the last burner ignition and there is no risk of post-boiling, suppressing the heat release from the hot water in the detour will result in insufficient initial heating of the burner Water can be supplied to the downstream side of the tapping pipe in a warmed state.

It is a schematic block diagram of the gas water heater of embodiment of this invention.

  An embodiment of the present invention will be described with reference to FIG. FIG. 1 shows a schematic configuration of a gas water heater 1 according to an embodiment of the present invention. The gas water heater 1 includes a heat exchanger 2 and a gas burner 3. The heat exchanger 2 is disposed in the main body case 4 of the gas water heater 1 that has a long rectangular shape in the vertical direction (vertical direction in FIG. 1). The water supply pipe 5 is arranged in the vertical direction in the main body case 4. One end of the water supply pipe 5 is connected to the inlet side of the heat exchanger 2 in the main body case 4, and the other end of the water supply pipe 5 is connected to a water pipe (not shown) outside the main body case 4. ing. Furthermore, the hot water discharge pipe 6 is also arranged in the vertical direction in the main body case 4. One end of the hot water supply pipe 6 is connected to the outlet side of the heat exchanger 2 in the main body case 4, and the hot water tap 7 is connected to the other end of the hot water supply pipe 6 outside the main body case 4.

  In addition, in the main body case 4, a gas burner 3 for heating the heat exchanger 2 is disposed below the heat exchanger 2. Gas is supplied to the gas burner 3 through a gas supply path (not shown). In the main body case 4, one bypass pipe 10 is provided in the middle of the hot water supply pipe 6. As shown in FIG. 1, one end of the bypass pipe 10 is connected to the upstream side (upper side in FIG. 1) of the outgoing hot water pipe 6 and communicates with the upstream side. Furthermore, the other end of the bypass pipe 10 is connected to the downstream side (the lower side in FIG. 1) of the hot water supply pipe 6 and communicates with the downstream side. As a result, one end of the bypass pipe 10 branches from the upstream side of the hot water discharge pipe 6, and the other end of the bypass pipe 10 joins the downstream side of the hot water discharge pipe 6. And the heat insulating material 14 is provided in the state which covers the outer periphery of the piping 10 for bypasses. The bypass pipe 10 is an example of the bypass circuit of the present invention.

  Next, in the gas water heater 1 of this embodiment, the operation | movement which suppresses the fluctuation | variation of the temperature of the hot water which flows into the downstream of the hot water piping 6 is demonstrated. By opening the hot-water tap 7 shown in FIG. 1, the flow rate of water supplied from the water pipe to the water supply pipe 5 becomes a predetermined amount by a flow rate sensor (not shown) provided in the water supply pipe 5. When this is detected, gas is supplied to the gas burner 3 and the gas burner 3 is ignited. As a result, the heat exchanger 2 is heated by the combustion heat of the gas burner 3. The water supplied to the heat exchanger 2 through the water supply pipe 5 is heated by the combustion heat to become hot water having a predetermined temperature. The hot water is discharged from the heat exchanger 2 to the hot water discharge pipe 6 and then discharged through the hot water tap 7. At the same time, the hot water flows into the bypass pipe 10 from the upstream side of the hot water discharge pipe 6, then flows through the bypass pipe 10 and is supplied to the downstream side of the hot water discharge pipe 6. In addition, the piping 5 for water supply is an example of the water supply path of this invention, and the piping 6 for hot water supply is an example of the hot water supply path of this invention.

  In this embodiment, even when a post-boiling phenomenon occurs and the temperature of hot water on the upstream side of the hot water supply pipe 6 rises during the hot water operation of the heat exchanger 2, as described below, the downstream of the hot water supply pipe 6 An increase in the temperature of hot water flowing to the side can be suppressed. After opening the hot-water tap 7 shown in FIG. 1 and starting the hot water discharge operation of the heat exchanger 2, when the hot water tap 7 is closed and the previous hot water discharge operation is stopped and a certain amount of time has elapsed, the heat exchanger When the remaining heat of 2 is transferred to the hot water remaining in the heat exchanger 2, a post-boiling phenomenon of this hot water occurs. Furthermore, before the next hot-water supply operation is started after the previous hot-water supply operation is stopped, the hot water has flowed into the bypass pipe 10 from the upstream side of the hot-water supply pipe 6 by the previous hot-water supply operation. Thus, hot water having a temperature close to the target temperature remains in the bypass pipe 10. In this embodiment, since the outer periphery of the bypass pipe 10 is covered with the heat insulating material 14, the heat dissipation from the bypass pipe 10 can be suppressed by the heat insulating material 14. For this reason, it is possible to suppress the temperature of the hot water remaining in the bypass pipe 10 from decreasing from the target temperature after the previous hot water discharge operation is stopped.

  In this state, when a certain amount of time has elapsed from the stop of the previous hot-water supply operation and the next hot-water supply operation is started by opening the hot-water tap 7, when a post-boiling phenomenon occurs, the temperature is higher than the target temperature. The hot water that has risen in temperature flows from the heat exchanger 2 to the upstream side of the hot water piping 6 and then flows toward the downstream side of the hot water piping 6. At the same time, part of the hot water that has risen to a temperature higher than the target temperature flows into the bypass pipe 10. At this time, the hot water flowing into the bypass pipe 10 pushes out the hot water having a temperature close to the target temperature remaining in the bypass pipe 10 to the downstream side of the hot water discharge pipe 6. When hot water having a temperature close to the target temperature is pushed out to the downstream side of the hot water discharge pipe 6, the hot water that has risen to a temperature higher than the target temperature by the next hot water discharge operation reaches the downstream side of the hot water supply pipe 6. As a result, on the downstream side of the hot water supply pipe 9, mixed hot water in which hot water that has risen to a temperature higher than the target temperature and hot water having a temperature close to the target temperature remaining in the bypass pipe 10 is mixed. It can flow. Thereby, the raise of the temperature of the hot water which flows into the downstream of the piping 6 for hot water can be suppressed.

  On the other hand, in the next hot water discharge operation, after the start of water flow to the water supply pipe 5 is confirmed by a flow rate sensor (not shown) provided in the water supply pipe 5, the gas burner is delayed from the start of water flow. 3 ignites. Then, the water supplied to the heat exchanger 2 from the water supply pipe 5 is sent out from the heat exchanger 2 to the hot water supply pipe 6 without being heated. Thereby, even when hot water having a temperature lower than the target temperature is discharged to the upstream side of the tap water piping 6, as described below, a decrease in the temperature of the hot water flowing downstream of the tap water piping 6 is suppressed. it can. After stopping the previous hot-water operation, the hot-water tap 7 is opened to start the next hot-water operation. After the flow sensor confirms the start of water flow to the water supply pipe 5, the gas burner 3 is ignited. In this case, as a result of insufficient heating of the water supplied to the heat exchanger 2 after the start of the next hot water operation, hot water having a temperature lower than the target temperature is discharged from the heat exchanger 2 to the hot water piping 6. Flows out toward the downstream side of the piping 6 for hot water after being discharged to the upstream side. At the same time, part of the hot water having a temperature lower than the target temperature flows into the detour route 10. At this time, the hot water that has flowed into the bypass pipe 10 causes the hot water remaining in the bypass pipe 10 to be pushed downstream of the hot water discharge pipe 6 by the previous hot water discharge operation. At this time, hot water having a temperature close to the target temperature remains in the bypass pipe 10 in a state where a short time has elapsed since the stop of the last hot water operation. When hot water having a temperature close to the target temperature is pushed out to the downstream side of the tap water piping 6, hot water having a temperature lower than the target temperature reaches the downstream side of the tap water piping 6 by the next tap water operation. As a result, mixed hot water in which hot water having a temperature lower than the target temperature and hot water having a temperature close to the target temperature are mixed can flow downstream of the hot water supply pipe 6. Thereby, the fall of the temperature of the hot water which flows into the downstream of the piping 6 for hot water can be suppressed. Particularly in the present embodiment, the heat insulating material 14 can suppress heat radiation from the bypass pipe 10. For this reason, it is possible to suppress the temperature of the hot water remaining in the bypass pipe 10 from decreasing from the target temperature after the previous hot water discharge operation is stopped. As a result, since the temperature drop of the hot water mixed with the hot water having a temperature lower than the target temperature is suppressed in the next hot water operation, the temperature of the mixed hot water flowing downstream of the hot water supply pipe 6 is reduced. Can be effectively suppressed.

  In the gas water heater 1 of the present embodiment, when the next hot water discharge operation is started when the post-boiling phenomenon occurs, the gas burner 3 is ignited with a delay from the start of water flow to the water supply pipe 5 together with the post-boiling phenomenon. A phenomenon will occur. In such a case, as will be described below, fluctuation (increase and decrease) in the temperature of hot water flowing downstream of the hot water discharge pipe 6 can be suppressed. When the next hot-water operation is started when the post-boiling phenomenon has occurred, the hot-water supply pipe 9 is used in the same manner as in the case where the post-boiling phenomenon has occurred until a certain amount of time has elapsed since the next hot water operation. The hot water that has risen to a temperature higher than the target temperature and the hot water having a temperature close to the target temperature that has remained in the bypass pipe 10 can flow to the downstream side. Thereby, the raise of the temperature of the hot water which flows into the downstream of the piping 6 for hot water can be suppressed. At this time, part of the hot water that has risen to a temperature higher than the target temperature also flows into the bypass pipe 10.

  Until a certain period of time elapses thereafter, hot water having a temperature lower than the target temperature is discharged from the heat exchanger 2 due to the ignition of the gas burner 3 with a delay from the start of water supply to the water supply pipe 5. After the hot water is discharged to the upstream side of the pipe 6, it flows toward the downstream side of the hot water discharge pipe 6. At the same time, part of the hot water having a temperature lower than the target temperature flows into the bypass pipe 10. At this time, the hot water that has flowed into the bypass pipe 10 and is raised to a temperature higher than the target temperature remaining in the bypass pipe 10 is pushed out to the downstream side of the hot water discharge pipe 6. As a result, mixed hot water in which hot water having a temperature lower than the target temperature is mixed with hot water having a temperature higher than the target temperature pushed out from the bypass pipe 10 to the downstream side is caused to flow downstream. be able to. Thereby, the fall of the temperature of the hot water which flows into this downstream can be suppressed.

  Subsequently, when a certain amount of time has elapsed, the hot water maintained at the target temperature is discharged from the heat exchanger 2 to the upstream side of the hot water discharge pipe 6 by the next hot water discharge operation in which the gas burner 3 is ignited, and then the hot water discharge pipe. 6 flows toward the downstream side. At the same time, part of the hot water maintained at the target temperature flows into the bypass pipe 10. At this time, hot water having a temperature lower than the target temperature remaining in the bypass pipe 10 is pushed out downstream of the hot water discharge pipe 6 by the hot water flowing into the bypass pipe 10. As a result, the hot water kept at the target temperature and the hot water having a temperature lower than the target temperature pushed out from the bypass pipe 10 to the downstream side can be flowed to the downstream side. . Thereby, the rise in the temperature of the hot water flowing downstream is suppressed.

  When a certain amount of time has passed, the temperature of the hot water flowing through the hot water piping 6 and reaching the downstream side of the hot water piping 6 is maintained at the target temperature by the next hot water discharge operation when the gas burner 3 is ignited. At the same time, part of the hot water maintained at the target temperature flows into the bypass pipe 10. At this time, the hot water kept at the target temperature remaining in the bypass pipe 10 is pushed out to the downstream side of the hot water discharge pipe 6 by the hot water flowing into the bypass pipe 10. As a result, the temperature of the hot water flowing downstream can be maintained at the target temperature.

<Effect of this embodiment>
In the gas water heater 1 of the present embodiment, even if the temperature of hot water upstream of the hot water discharge pipe 6 may rise due to a post-boiling phenomenon after the previous hot water discharge operation is stopped, The mixed hot water obtained by mixing the hot water whose temperature has increased with the hot water remaining in the bypass pipe 10 by the previous hot water discharge operation can be flowed to the downstream side of the hot water piping 6. Thereby, the raise of the temperature of the hot water which flows into the downstream of the piping 6 for hot water can be suppressed.
In addition, since the gas burner 3 is ignited after the start of water flow to the water supply pipe 5 at the time of the next hot water discharge operation, heating of the water flow becomes insufficient. The hot water having a temperature lower than the target temperature may flow, but this hot water and the hot water having a temperature close to the target temperature remain in the bypass pipe 10 by the previous hot water discharge operation on the downstream side of the hot water supply pipe 6. Then, a mixed hot water in which is mixed can be poured. Thereby, the fall of the temperature of the hot water which flows into the downstream of the piping 6 for hot water can be suppressed.
Therefore, the temperature of the hot water flowing downstream of the hot water supply pipe 6 can be reduced by a simple and inexpensive structure in which the bypass pipe 10 is provided in the hot water supply pipe 6 without performing complicated control by a conventional controller. Variation (increase and decrease) can be suppressed.

  In addition, since heat radiation from the bypass pipe 10 can be suppressed by the heat insulating material 14, it remains in the bypass pipe 10 after the last hot water discharge operation is stopped, and more than the target temperature in the next hot water discharge operation. It can suppress that the temperature of the hot water mixed with the low temperature hot water falls. As a result, it is possible to effectively suppress a decrease in the temperature of hot water flowing downstream of the hot water supply pipe 6 during the next hot water discharge operation.

  The present invention is not limited to the above-described embodiment, and can be implemented by appropriately changing a part of the configuration without departing from the spirit of the invention. In the above-described embodiment, the example in which the water supply pipe 5 and the hot water supply pipe 6 are arranged in the vertical direction in the main body case 4 of the gas water heater 1 is shown. A long rectangular shape may be formed, and a water supply pipe or a hot water supply pipe may be disposed in the main body case in the front-rear direction of the main body case. In addition, one bypass pipe 10 may be provided in the body case in the middle of the hot water pipe.

  In the above-described embodiment, an example in which one bypass pipe 10 is provided in the middle of the hot water discharge pipe 6 is shown, but the present invention is not limited thereto, and two bypass pipes are provided in the middle of the hot water discharge pipe 6. You may provide above. Also in this case, similarly to the above-described embodiment, each bypass pipe functions in the same manner as the bypass pipe 10, and fluctuations in the temperature of hot water flowing downstream of the hot water discharge pipe 6 can be suppressed.

  In an embodiment in which two or more bypass pipes are provided in the middle of the tap water pipe 6 (hereinafter referred to as other embodiments), a bypass is provided in the middle of the tap pipe 6 in the extending direction of the tap water pipe 6. Two or more pipes may be provided side by side independently. Further, as an embodiment in which two or more bypass pipes are provided (hereinafter referred to as other embodiments), the other end of one bypass pipe provided on the upstream side of the hot water discharge pipe 6 (with the hot water supply pipe 6). From the upstream side of the hot water discharge pipe 6 with respect to the merging end) and from the downstream side of the hot water supply pipe 6 with respect to one end of the one bypass pipe (a branch end from the hot water discharge pipe 6). One end of another bypass pipe provided on the downstream side of the hot water discharge pipe 6 with respect to the pipe is branched, and the other bypass pipe is connected to the other end of the one bypass pipe with respect to the other hot water discharge pipe. You may make it merge in the downstream of 6. Further, as a different embodiment, one end of the bypass pipe is branched from the upstream side of the tap water pipe 6, the other end of the bypass pipe is branched into a plurality, and the plurality of other ends are connected to the one end. Alternatively, it may be joined to a different position of the hot water supply pipe 6 on the downstream side of the hot water supply pipe 6. In addition, in other embodiments, other embodiments, and different embodiments, the outer periphery of each bypass pipe may be covered with a heat insulating material. If it does in this way, like the embodiment mentioned above, it can control that the temperature of the hot water which remains in each detour pipe after the last hot water discharge operation stops.

  Moreover, although the example which applied this invention to the gas water heater 1 was shown in embodiment mentioned above, even if this invention is applied to the water heater with a water heater and a heating apparatus with a heating function, it is not restricted to this. Good.

  1 .... Gas water heater, 2 .... Heat exchanger, 3 .... Gas burner, 5 .... Piping for water supply, 6 .... Piping for hot water, 10 .... Piping for diversion, 14 .... Heat insulation material.

Claims (2)

A water heater having a heat exchanger that heats water supplied from a water supply channel by combustion heat of a burner and discharges water to a hot water supply channel,
One end is branched from the upstream side of the tapping channel, and the other end includes a detour that joins the downstream side of the tapping channel,
Due to the fact that hot water has flowed into the detour from the upstream side of the tapping channel by the last tapping, hot water remains in the detour after the last tapping,
At the time of the next hot water, mixed hot water mixed with the hot water remaining in the bypass and hot water flowing from the upstream side of the hot water pipe to the downstream side of the hot water pipe by the next hot water, A hot water heater characterized by flowing downstream.   The water heater according to claim 1, further comprising a heat insulating material covering an outer periphery of the bypass.

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