JP2009092286A - Water heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water heater capable of adjusting the amount of drainage generated from a sub-heat exchanger. <P>SOLUTION: In this water heater 1, the drainage stored in a drain tank 17 is sucked by a drain pump 20, and jetted into a spray from a nozzle 22. A part of tap water flowing into a first supply pipe 30 can be allowed to flow to a main heat exchanger 9 through a bypass pipe 38 when a level of the drainage in the drain tank 17 becomes higher than an upper limit water level or more to prevent the drainage from being excessively sprayed outside of the device 2. Thus the amount of tap water flowing into the sub-heat exchanger 10 can be reduced, and the generation of drainage in the sub-heat exchanger 10 can be effectively reduced. Further as a solenoid valve 45 is disposed in the bypass pipe 38, latent heat from combustion exhaust can be sufficiently recovered in the sub-heat exchanger 10 by normally closing the bypass pipe 38. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a water heater, and more particularly, to a water heater provided with a heat exchanger that recovers sensible heat and latent heat from combustion exhaust of a burner to heat water.

  Conventionally, a main heat exchanger mainly for the purpose of sensible heat recovery is provided upstream in the combustion exhaust passage, and a secondary heat exchanger mainly for the purpose of recovering latent heat is provided on the downstream side to achieve a high heat exchange rate. An obtained latent heat recovery type water heater is known (for example, see Patent Document 1). This type of water heater has, for example, a finned tube type auxiliary heat exchanger and a finned tube type main heat exchanger that are spaced apart in two upper and lower stages, and in the space between them, the latent heat is generated by the auxiliary heat exchanger. The drain receiving tray for receiving the drain (condensed water after the latent heat recovery) generated by the recovery is provided.

In such a latent heat recovery type water heater, first, the high-temperature combustion exhaust from the burner flows between the main fins of the main heat exchanger through the air supply fan, and heat is exchanged well. Further, the combustion exhaust whose temperature has decreased flows between the sub-fins of the sub-heat exchanger, and heat is exchanged well in the sub-heat exchanger, and is discharged outside the appliance through the exhaust hood. On the other hand, the drain generated by the latent heat recovery in the auxiliary heat exchanger placed above is collected in the drain pan, processed in the neutralizer through the drain discharge pipe, and then discharged to drainage facilities such as sewers. It has become so. In order to eliminate the need for drainage equipment, for example, the drain generated in the secondary heat exchanger (sub-heat exchanger) is stored in the tank, and the drain stored in the tank is stored in the instrument. There is also known a water heater that can be finely discharged to the outside (for example, see Patent Document 2). In this water heater, the drain in the tank can be sucked up by a pump and discharged from the nozzle in the form of a mist.
JP 2002-267273 A JP 2007-101167 A

  However, in the water heater described in Patent Document 2, since the amount of drain generated in the auxiliary heat exchanger increases when used for a long time, if the drainage from the tank is not in time, the drain overflows from the tank. There was a risk that it would end up.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a water heater capable of adjusting the amount of drain generated in the auxiliary heat exchanger.

  In order to achieve the above object, a water heater according to a first aspect of the present invention includes a burner that burns fuel gas in a combustion chamber provided in the appliance, and recovers sensible heat from the combustion exhaust of the burner. A main heat exchanger for heating the water flow in the heat transfer tube, and a sub heat exchanger for recovering latent heat from the combustion exhaust gas passing through the main heat exchanger and heating the water flow in the second heat transfer tube A first supply pipe interposed between a water supply port provided in the appliance, an inlet of the second heat transfer pipe, an outlet of the second heat transfer pipe, and an inlet of the first heat transfer pipe A second supply pipe interposed between the tank, a tank for temporarily storing the drain generated in the auxiliary heat exchanger, a drain discharging means for discharging the drain in the tank to the outside of the instrument, and the first One supply pipe and the second supply pipe are interposed, and a part of the water flow of the first supply pipe is transferred to the second supply pipe. Comprises a bypass pipe for feeding, the passing water amount adjusting means for adjusting the passing water of the bypass pipe.

  The water heater of the invention according to claim 2 is characterized in that, in addition to the configuration of the invention of claim 1, the water flow rate adjusting means is provided in the bypass pipe.

  In addition to the configuration of the invention according to claim 1 or 2, the water heater of the invention according to claim 3 includes a water level detection means for detecting a drain water level in the tank, and a drain detected by the water level detection means. And a water flow rate control means for controlling the water flow rate adjusting means based on the water level.

  In addition to the configuration of the invention described in claim 1 or 2, the water heater of the invention according to claim 4 is characterized by the combustion time of the burner, the non-combustion time of the burner, the combustion amount of the burner, and the output of the appliance. Adjusting the water flow rate by at least one of a preset temperature of hot water supplied from the water gate, a water inlet temperature at the water inlet, a water inlet amount per unit time at the water inlet, an outside air temperature, and a drain discharge time by the drain discharge means Water flow rate control means for controlling the means is provided.

  In the water heater of the invention according to claim 1, a part of the water flow of the first supply pipe is supplied to the second supply pipe by the bypass pipe, so the amount of water flowing to the second heat transfer pipe of the auxiliary heat exchanger Can be relatively reduced, and the amount of drain generated in the auxiliary heat exchanger can be reduced. Furthermore, the water flow rate in the bypass pipe can be freely adjusted by the water flow rate adjusting means. For example, when the amount of drain generated is small, the amount of water passing through the bypass pipe is reduced. Thereby, since latent heat can fully be recovered in the auxiliary heat exchanger, heat exchange can be performed efficiently. In addition, if the amount of drain generated is large, increase the water flow rate of the bypass pipe. Thereby, since the amount of water flow to the sub heat exchanger is reduced, the amount of drain generation in the sub heat exchanger can be reduced. Therefore, it is possible to prevent the drain from overflowing from the tank even when the water heater is used for a long time.

  Further, in the water heater of the invention according to claim 2, in addition to the effect of the invention of claim 1, the water flow rate adjusting means is provided in the bypass pipe, so compared with the case where it is provided in the first supply pipe, The amount of water flow in the second heat transfer tube can be indirectly adjusted. For example, when reducing the water flow rate in the second heat transfer pipe, the water flow rate of the bypass pipe may be increased by the water flow rate adjusting means. Moreover, what is necessary is just to reduce the water flow rate of a bypass pipe by a water flow rate adjustment means, when increasing the water flow rate in a 2nd heat exchanger tube.

  In the water heater of the invention according to claim 3, in addition to the effect of the invention of claim 1 or 2, the drain water level in the tank is detected by the water level detection means. And since the water flow rate control means controls the water flow rate adjusting means based on the detected drain water level, the water flow rate of the bypass pipe can be adjusted according to the drain generation amount.

  Further, in the water heater of the invention according to claim 4, in addition to the effect of the invention of claim 1 or 2, the longer the burner combustion time, the more continuously the drain is generated from the auxiliary heat exchanger. The amount of drain increases. In addition, the shorter the non-burning time of the burner, the more the drain in the tank increases because the drain in the tank does not evaporate. Also, the more burner burns, the greater the amount of drain generated in the auxiliary heat exchanger, and the greater the amount of drain in the tank. In addition, the lower the set temperature of hot water, the greater the amount of drain generated in the auxiliary heat exchanger, and the greater the amount of drain in the tank.

  In addition, the lower the incoming water temperature at the water supply port, the greater the amount of drain generated in the auxiliary heat exchanger, so the amount of drain in the tank also increases. Moreover, since the amount of drain generation in the auxiliary heat exchanger increases as the amount of water entering per unit time at the water supply port increases, the amount of drain in the tank also increases. Also, the lower the outside air temperature, the greater the amount of drain generated in the auxiliary heat exchanger, and the greater the amount of drain in the tank. As the drain discharge time by the drain discharge means is shorter, the drain in the tank is not discharged, so the amount of drain in the tank increases. Based on these properties, the water flow rate adjustment control means controls the water flow rate adjustment means, so that the water flow rate of the bypass pipe can be adjusted according to the amount of drain generated.

  Hereinafter, a water heater 1 according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a side sectional view of the water heater 1 according to the first embodiment, FIG. 2 is an explanatory diagram of a lower limit water level (H1) and an upper limit water level (H2) in the drain tank 17, and FIG. 4 is a flowchart of a drain discharge process by the controller 40.

  First, the overall structure of the water heater 1 will be described. As shown in FIG. 1, the water heater 1 includes a box-shaped appliance 2. A combustion chamber 3 is provided in the upper stage inside the instrument 2. A combustion air supply fan 5 connected to the motor 4 is fixed below the combustion chamber 3. Furthermore, a controller 40 that controls the combustion operation of the water heater 1 is provided inside the appliance 2. In addition, air supply ports 6 and 6 for taking outside air as combustion air are respectively provided in the lower front portion and the lower back portion of the instrument 2. Further, an exhaust hole 7 for exhausting combustion exhaust after recovery of sensible heat and latent heat to the outside of the instrument 2 is provided in the upper front portion of the instrument 2.

  The controller 40 includes a CPU as a central processing unit (not shown). Furthermore, ROM, which is a read-only memory that stores various programs, RAM, which is a readable / writable memory that temporarily stores programs that are being executed, and that stores various data, etc., and flash memory that is nonvolatile memory Etc. are built-in.

  Next, the internal structure of the combustion chamber 3 will be described. As shown in FIG. 1, a burner 8 for burning a mixed gas of fuel gas and primary air supplied from a combustion air supply fan 5 is provided below the combustion chamber 3. A main heat exchanger 9 that mainly recovers sensible heat in the combustion exhaust gas flowing from the burner 8 is provided above the burner 8. Further, above the main heat exchanger 9, there is provided a sub heat exchanger 10 that mainly recovers latent heat from the combustion exhaust from which sensible heat has been recovered, and generates drain in accordance with the latent heat recovery. . In addition, the main heat exchanger 9 is a fin tube type provided with the main heat exchanger tube 9a and the main fin 9b, and it is preferable to use the thing made from copper excellent in thermal conductivity. The auxiliary heat exchanger 10 is also of a fin tube type including the auxiliary heat transfer tubes 10a and the auxiliary fins 10b, and is preferably made of stainless steel having excellent corrosion resistance against drain.

  In addition, a combustion chamber exhaust hole 27 through which the combustion exhaust after heat exchange by the main heat exchanger 9 and the sub heat exchanger 10 is discharged to the outside of the combustion chamber 3 is provided in the upper part of the combustion chamber 3. A cylindrical exhaust hood 28 is provided between the combustion chamber exhaust hole 27 and the exhaust hole 7. The exhaust hood 28 is provided so as to protrude outward from the instrument 2, and an exhaust outlet 29 is formed at the tip thereof.

  Next, a drain discharge structure will be described. As shown in FIG. 1, a stainless steel drain tray 11 is inclined below the auxiliary heat exchanger 10. The drain tray 11 receives drain generated in the auxiliary heat exchanger 10. A drain hole 12 for discharging the drain is provided at a contact portion between the drain tray 11 and the combustion chamber 3. Further, a drain exhaust pipe 13 is connected to the drain hole 12. An S-shaped trap 14 that is bent in an S shape is provided in the middle of the drain exhaust pipe 13. By collecting the drain in the S-shaped trap 14, it is possible to prevent the combustion exhaust from passing through the drain exhaust pipe 13 and returning into the instrument 2.

  A neutralizer 15 for neutralizing acidic drain is connected to one end of the drain exhaust pipe 13 on the downstream side. The outlet of the neutralizer 15 is connected to a drain exhaust pipe 16 through which neutralized drain flows. A drain tank 17 for temporarily storing the neutralized drain is provided below the outlet of the drain discharge pipe 16 where the drain is discharged.

  The drain tank 17 is formed in a box shape whose top surface is open. The drain tank 17 is provided with a drain hole (not shown), and a drain exhaust pipe 18 is connected to the drain hole. A drain pump 20 is connected to one end of the drain exhaust pipe 18 on the downstream side. Further, a drain exhaust pipe 21 is connected to the outlet of the drain pump 20. The drain exhaust pipe 21 extends from the drain pump 20 toward the upper portion of the appliance 2, penetrates the lower surface of the exhaust hood 28, and is bent at a right angle toward the exhaust outlet 29 inside the exhaust hood 28. And the drain discharge pipe 21 is extended to the exhaust outlet 29, and the nozzle 22 for ejecting drain in the shape of a mist is attached to the front-end | tip.

  Next, the piping configuration inside the instrument 2 will be described. As shown in FIG. 1, a water supply port 24, a hot water outlet 25, and a gas supply port 26 are provided at the bottom of the instrument 2. A first supply pipe 30 is connected to the water supply port 24 into which tap water flows. The first supply pipe 30 extends toward the upper part in the appliance 2, and one end on the downstream side through which the tap water flows is connected to the sub heat transfer pipe 10 a (the “second heat transfer pipe of the present invention”). Is equivalent to the entrance). A second supply pipe 31 is connected to the outlet of the sub heat transfer pipe 10a. The second supply pipe 31 is folded downward and extended, and one end portion on the downstream side is connected to the inlet of the main heat transfer pipe 9a of the main heat exchanger 9 (corresponding to the “first heat transfer pipe” of the present invention). Has been. And the hot water pipe 32 is connected to the exit of the main heat exchanger tube 9a. The hot water discharge pipe 32 is folded downward and extended, and one end portion on the downstream side is connected to the hot water outlet 25.

  A gas pipe 33 is interposed between the gas supply port 26 and the burner 8. The main electromagnetic valves 35 and 37 are provided on the downstream side of the gas flow in the gas pipe 33, and the gas proportional valve 36 is provided between the main electromagnetic valves 35 and 37. Further, a bypass pipe 38 is provided between the middle of the first supply pipe 30 and the middle of the second supply pipe 31. The bypass pipe 38 supplies a part of tap water flowing through the first supply pipe 30 to the second supply pipe 31 and supplies it to the main heat transfer pipe 9a. An electromagnetic valve 45 (corresponding to the “water flow rate adjusting means” of the present invention) that opens and closes the flow path is provided at an intermediate position of the bypass pipe 38. A water-side control unit 34 including a water flow sensor and a water governor is provided on the upstream side of the first supply pipe 30 through which tap water flows. The water flow sensor, the main electromagnetic valves 35 and 37, the gas proportional valve 36, the motor 4, the drain pump 20, and the electromagnetic valve 45 in the water-side control unit 34 described above are electrically connected to the controller 40. That is, the water flow sensor, the main electromagnetic valve 35 and the gas proportional valve 36, the motor 4, the drain pump 20, and the electromagnetic valve 45 in the water side control unit 34 are controlled by the controller 40.

  Next, adjustment of the water flow rate of the bypass pipe 38 by the electromagnetic valve 45 will be described. As shown in FIG. 1, the electromagnetic valve 45 opens and closes the flow path of the bypass pipe 38. The electromagnetic valve 45 is normally closed. In this state, all the tap water passing through the first supply pipe 30 flows into the sub heat transfer pipe 10 a of the sub heat exchanger 10. Here, for example, when the amount of drain generation in the auxiliary heat exchanger 10 increases due to long-time use of the water heater 1, a large amount of drain must be discharged out of the appliance 2, so it is necessary to reduce the amount of drain generation. There is. In this case, the electromagnetic valve 45 is opened. Then, a part of the tap water passing through the first supply pipe 30 does not flow into the sub heat transfer pipe 10 a but flows into the main heat transfer pipe 9 a via the second supply pipe 31. That is, since the amount of tap water flowing into the auxiliary heat transfer pipe 10a is relatively reduced, the amount of drain generated in the auxiliary heat exchanger 10 can be effectively reduced. In this embodiment, the controller 40 adjusts the opening / closing of the electromagnetic valve 45 in accordance with the drain water level of the drain tank 17. Thereby, the amount of drain generation in the auxiliary heat exchanger 10 can be automatically adjusted according to the drain water level. The relationship between the drain water level and the control of the electromagnetic valve 45 will be described later.

  Incidentally, as described above, the electromagnetic valve 45 adjusts the amount of water flow through the bypass pipe 38. Then, the amount of tap water flowing into the auxiliary heat transfer pipe 10a is indirectly adjusted by adjusting the amount of water flow through the bypass pipe 38. This can reduce the water passage pressure loss as compared with the case where the electromagnetic valve 45 is provided on the downstream side of the first supply pipe 30. Furthermore, since the tap water flowing into the auxiliary heat transfer pipe 10a can be ensured regardless of whether the electromagnetic valve 45 is opened or closed, the auxiliary heat transfer pipe 10a can be prevented from being in an empty state.

  Next, the drain water level of the drain tank 17 will be described. As shown in FIG. 2, the drain tank 17 is set with a lower limit water level (H1) and an upper limit water level (H2) of the drain. A water level sensor 51 is installed at a position corresponding to H1. On the other hand, a water level sensor 52 is installed at a position corresponding to H2. These water level sensors 51 and 52 are general electrode type water level sensors. The water level sensors 51 and 52 are connected to the controller 40 (see FIG. 1), and output an on signal when the water level is detected, and output an off signal when the water level is not detected. The controller 40 determines whether the current water level in the drain tank 17 is less than H1, within the range from H1 to less than H2, or greater than H2 based on the detection signals output from the water level sensors 51 and 52. Can be determined. The water level detection may be performed only at the upper limit water level (H2).

  Next, control of the drain pump 20 and the electromagnetic valve 45 will be described. The controller 40 controls the driving of the drain pump 20 and the opening / closing of the electromagnetic valve 45 according to the drain water level of the drain tank 17. For example, when it is determined that the drain water level is equal to or higher than H1, the drain pump 20 is driven. If it is less than H1, the drain pump 20 is stopped. Thereby, the power consumption concerning the drive of the drain pump 20 can be saved. Moreover, when the drain water level is equal to or higher than the upper limit water level H2, it is estimated that the amount of drain generated in the auxiliary heat exchanger 10 is large. That is, if the drain discharge is not in time for the drain generation amount, the drain may overflow from the drain tank 17. In order to avoid such a situation, the electromagnetic valve 45 is opened. Then, as described above, part of the tap water flowing through the first supply pipe 30 flows into the main heat transfer pipe 9a via the bypass pipe 38. Thereby, since the amount of the tap water which flows into the sub heat exchanger tube 10a of the sub heat exchanger 10 decreases relatively, the amount of drain generation in the sub heat exchanger 10 can be reduced. That is, the amount of drain sprayed from the nozzle 22 can be reliably reduced.

  Next, the combustion operation of the water heater 1 will be described. As shown in FIG. 1, first, when a hot-water tap (not shown) is opened, tap water flows through the first supply pipe 30. Then, the detection signal from the water quantity sensor in the water side control unit 34 is output, and the controller 40 starts the main hot water supply control operation. Then, a predetermined pre-purge is performed by the combustion air supply fan 5. Thereafter, the ignition operation of the burner 8 is performed by an igniter (not shown), the main electromagnetic valve 35 and the gas proportional valve 36 of the burner 8 are opened, and gas is supplied from the gas pipe 33 to the burner 8.

  Next, when the ignition operation is finished, the proportional control of the gas is started. In this proportional control, the gas proportional valve 36 is controlled according to the difference between the hot water temperature detected by the hot water temperature thermistor (not shown) and the set temperature. Thereby, since the gas amount can be continuously changed, the outlet temperature of the main heat exchanger 9 can be kept constant. Further, the rotational speed of the combustion air supply fan 5 is controlled in accordance with the change in the gas amount by the gas proportional valve 36. Therefore, control is performed so that the gas amount and the air supply amount are always maintained in a predetermined relationship.

  By the way, in this water heater 1, since the main heat exchanger 9 is provided upstream of the exhaust passage and the auxiliary heat exchanger 10 is provided downstream of the exhaust passage, the high-temperature combustion exhaust gas flowing from the burner 8 is The combustion air supply fan 5 flows between the main fins 9b of the main heat exchanger 9 to exchange heat well. Furthermore, the combustion exhaust gas whose temperature has decreased flows between the sub fins 10b of the sub heat exchanger 10 and is also exchanging heat well in the sub heat exchanger 10 and is discharged to the outside through the exhaust hood 28.

  On the other hand, the combustion exhaust discharged from the main heat exchanger 9 is discharged at a high temperature of about 200 ° C. in order to prevent partial drain generation in a local low temperature portion such as the main heat transfer tube 9a which is a water flow portion. Has been. On the other hand, the auxiliary heat exchanger 10 collects sensible heat that could not be recovered by the main heat exchanger 9, and drainage is generated when the combustion exhaust gas temperature becomes the dew point or lower, so that latent heat can also be recovered. The drain generated here is collected in the drain pan 11, passes through the drain discharge pipe 13, and is neutralized in the neutralizer 15. The drain neutralized by the neutralizer 15 is dropped through the drain exhaust pipe 16 and stored in the drain tank 17.

  Next, the drain discharge process by the controller 40 will be described with reference to the flowchart of FIG. The drain discharge process is executed separately from the main process related to the combustion control of the water heater 1, but may be executed as a part of the main process.

  First, the drain water level in the drain tank 17 is detected (S1). The drain water level is determined by detection signals output from the water level sensors 51 and 52. Next, it is determined whether or not the drain water level is equal to or higher than H1 (S2). For example, when the detection signals from the water level sensors 51 and 52 are both off signals, since the drain water level is less than H1 (S2: NO), it is estimated that the amount of drain generated in the auxiliary heat exchanger 10 is small. In this case, the drain pump 20 is stopped (S8). Further, the electromagnetic valve 45 is closed in order to promote the latent heat recovery by the auxiliary heat exchanger 10 (S9). Thereby, since all the tap water which flows through the 1st supply pipe | tube 30 flows in into the sub heat exchanger tube 10a of the sub heat exchanger 10, latent heat can fully be collect | recovered from combustion exhaust gas. The drain generated in the auxiliary heat exchanger 10 flows through the drain tray 11, the drain exhaust pipe 13, the neutralizer 15, and the drain exhaust pipe 16 and is stored in the drain tank 17.

  Next, the process returns to S1, and the drain water level is detected again. And when the drain water level of the drain tank 17 rises and the water level sensor 51 detects drain, an ON signal is output from the water level sensor 51. In this case, since the drain water level is H1 or higher (S2: YES), it is subsequently determined whether the drain water level is H2 or higher (S3). Here, when the detection signal from the water level sensor 52 is an off signal, the drain water level is in the range from H1 to less than H2 (S3: NO), so the drain pump 20 is driven (S6) and the solenoid valve 45 is closed. (S7). Then, the drain accumulated in the drain tank 17 is sucked and supplied to the nozzle 22 through the drain exhaust pipes 18 and 21. And since the discharge pressure of the drain pump 20 is applied to the nozzle 22, the mist-like drain is ejected vigorously from the nozzle 22. Further, the nozzle 22 is disposed in the exhaust hood 28 at the downstream end in the combustion exhaust discharge direction. Therefore, there is no possibility that the mist-like drain ejected from the nozzle 22 adheres to the inside of the exhaust hood 28 and erodes the instrument. In addition, the drain can be blown farther from the appliance 2 on the combustion exhaust flowing in the exhaust hood 28. In addition, since the solenoid valve 45 is closed, all the tap water flows into the sub heat transfer pipe 10a of the sub heat exchanger 10. Therefore, it is possible to sufficiently recover the latent heat from the combustion exhaust after the sensible heat recovery.

  Next, the process returns to S1, and the drain water level is detected again. And when the drain water level of the drain tank 17 further rises and both of the water level sensors 51 and 52 detect the drain, ON signals are output from the water level sensors 51 and 52, respectively. In this case, since the drain water level is equal to or higher than the upper limit water level H2 (S3: YES), the drain pump 20 is driven (S4), and the electromagnetic valve 45 is opened (S5). Then, a part of the tap water passing through the first supply pipe 30 flows through the bypass pipe 38 and flows into the main heat transfer pipe 9 a of the main heat exchanger 9. Thereby, since the amount of tap water flowing into the sub heat transfer pipe 10a of the sub heat exchanger 10 is reduced, the amount of drain generation in the sub heat exchanger 10 can be effectively reduced.

  In this way, by repeating a series of operations related to drain discharge, the amount of drain spray from the nozzle 22 can be adjusted according to the drain water level in the drain tank 17. And by adjusting the drain generation amount in the auxiliary heat exchanger 10 according to the drain water level, it is possible to prevent the drain from overflowing from the drain tank 17 and to effect that the drain is excessively sprayed outside the appliance 2. Can be prevented. Further, if the drain water level is within the allowable range, the sub heat exchanger 10 can sufficiently recover the latent heat by stopping the water flow through the bypass pipe 38, so that the thermal efficiency of the water heater 1 can be maintained. Furthermore, since the amount of drain generation can be adjusted, the capacity | capacitance of the drain tank 17 can also be made small.

  In the above description, the electromagnetic valve 45 shown in FIG. 1 corresponds to the “water flow rate adjusting means” of the present invention. 1 corresponds to the “first heat transfer tube” of the present invention, and the sub heat transfer tube 10a corresponds to the “second heat transfer tube” of the present invention. Further, the CPU of the controller 40 that executes S2 and S3 in the flowchart of FIG. 3 corresponds to the “water level determining means” of the present invention, and the CPU of the controller 40 that executes the processes of S5, S7, and S9 is “ Corresponds to “water quantity control means”.

  As described above, in the water heater 1 of the present embodiment, the drain stored in the drain tank 17 is sucked by the drain pump 20 and supplied to the nozzle 22, so that the drain is ejected from the nozzle 22 in the form of a mist. . Thereby, drainage for discharging the drain and piping work for the drainage are not required, and the burden on the installer can be reduced. In order to prevent the drain from being excessively sprayed outside the appliance 2, when the drain water level of the drain tank 17 becomes H2 or more, a part of the tap water flowing through the first supply pipe 30 is bypassed. 38 to the main heat exchanger 9. Thereby, since the amount of tap water flowing into the auxiliary heat exchanger 10 can be reduced, the amount of drain generation in the auxiliary heat exchanger 10 can be effectively reduced. In addition, since the bypass pipe 38 is provided with the electromagnetic valve 45, the auxiliary heat exchanger 10 can sufficiently recover the latent heat from the combustion exhaust gas by being normally closed.

  Needless to say, the present invention is not limited to the above-described embodiment, and various modifications are possible. For example, in the above embodiment, the electromagnetic valve 45 is provided in order to regulate the water flow rate of the bypass pipe 38, but an electric valve capable of continuously adjusting the flow path area by driving a motor may be provided. When an electric valve is used, the amount of water flow through the bypass pipe 38 can be continuously increased or decreased, so that the amount of drain generation can be controlled more finely.

  Moreover, in the said embodiment, in order to determine the drain water level of the drain tank 17, the two water level sensors 51 and 52 were used, However, You may use the number of water level sensors more than this. In this case, since the drain water level in the drain tank 17 can be detected more finely, it is possible to variously change the adjustment of the water flow rate in the bypass pipe 38.

  Further, in the above embodiment, the drain in the drain tank 17 is pumped up by the drain pump 20 and sprayed and discharged from the nozzle 22 in the form of a mist. For example, an ultrasonic vibrator is installed in the drain tank 17 to remove the drain. You may make it make it mist-like by ultrasonic vibration and to discharge out of the instrument 2.

  Further, the present invention can be applied to a type that does not spray drain. For example, in the case of draining together with the drainage of the bathroom (for example, a recirculation pipe), the drain tank 17 does not pass through the bypass pipe 38 when draining, and the drain tank 17 has a predetermined capacity when not draining. When the above is reached, water may be passed through the bypass pipe 38. As a result, the amount of drain generated temporarily decreases, so that it is possible to prevent the drain from overflowing from the drain tank 17.

  Furthermore, in the above-described embodiment, the amount of water flow in the bypass pipe 38 is adjusted by detecting the drain water level in the drain tank 17, and the amount of drain generated in the auxiliary heat exchanger 10 is adjusted. Time, burner 8 non-combustion time, burner 8 combustion amount, set temperature of hot water supplied from the outlet 25, incoming water temperature at the inlet 24, incoming water per unit time at the inlet 24, outside temperature, drain pump The amount of water passing through the bypass pipe 38 may be adjusted by using a driving time of 20 or the like. Therefore, instead of the water level sensors 51 and 52, modified examples using these methods will be described in order. In the description of the first to eighth modifications, the structure to be changed will be described with reference to the structure of the water heater 1 shown in FIG.

  First, the first modification will be described. In the first modification, the amount of water passing through the bypass pipe 38 is adjusted according to the combustion time of the burner 8. As the combustion time of the burner 8 is longer, drain continues to be generated in the auxiliary heat exchanger 10, so that the amount of drain in the drain tank 17 increases. In order to utilize this property, for example, a timer is provided in the controller 40. The CPU uses the output from the timer to measure the time after the burner 8 ignites as “burning time”, and determines whether the burning time is equal to or longer than a predetermined time. When it is determined that the combustion time is equal to or longer than the predetermined time, the drain amount in the drain tank 17 is expected to be large. In this case, the CPU opens the electromagnetic valve 45 to allow water to flow through the bypass pipe 38. Thereby, since the amount of water flow of the sub heat exchanger tube 10a of the sub heat exchanger 10 can be reduced, the amount of drain generation in the sub heat exchanger 10 can be reduced effectively. Further, when it is determined that the combustion time is less than the predetermined time, the drain amount in the drain tank 17 is expected to be small. In this case, the CPU closes the electromagnetic valve 45 in order not to allow water to flow through the bypass pipe 38. As a result, the amount of water flow through the sub heat transfer tube 10a of the sub heat exchanger 10 can be increased, so that the sub heat exchanger 10 can sufficiently recover the latent heat.

  Next, a second modification will be described. In the second modification, the amount of water passing through the bypass pipe 38 is adjusted according to the non-combustion time of the burner 8. As the non-burning time of the burner 8 is shorter, the drain in the drain tank 17 does not evaporate and the amount of drain generated during the combustion of the burner 8 increases, so the drain amount in the drain tank 17 also increases. In order to use this property, for example, a timer is provided in the controller 40 as in the first modification. The CPU uses the output from the timer to measure the time from when the burner 8 is extinguished until it is ignited as “non-burning time”, and determines whether the non-burning time within a predetermined time is equal to or shorter than the predetermined time. . If it is determined that the non-combustion time is equal to or shorter than the predetermined time, the drain amount in the drain tank 17 is expected to be large for the above reason. In this case, the CPU opens the electromagnetic valve 45 to allow water to flow through the bypass pipe 38. Thereby, since the amount of water flow of the sub heat exchanger tube 10a of the sub heat exchanger 10 can be reduced, the amount of drain generation in the sub heat exchanger 10 can be reduced effectively. Further, when it is determined that the non-burning time exceeds the predetermined time, the drain amount in the drain tank 17 is expected to be small for the above reason. In this case, the CPU opens the electromagnetic valve 45 to allow water to flow through the bypass pipe 38. As a result, the amount of water flow through the sub heat transfer tube 10a of the sub heat exchanger 10 can be increased, so that the sub heat exchanger 10 can sufficiently recover the latent heat.

  Next, a third modification will be described. In the third modification, the amount of water passing through the bypass pipe 38 is adjusted by the amount of combustion of the burner 8. As the burner 8 burns more, the amount of drain generated in the auxiliary heat exchanger 10 increases, so the amount of drain in the drain tank 17 also increases. In order to use this property, for example, the relationship between the combustion amount (kcal) of the burner 8 and the drain water level of the drain tank 17 is obtained. That is, when the burner 8 burns up, the drain water level in the drain tank 17 rises.

  Therefore, the amount of combustion (kcal / h) per unit time of the burner 8 is measured in advance. Thereby, the amount of combustion (kcal) in the burner 8 so far can be calculated from the actual combustion time (h) of the burner 8. When it is determined that the combustion amount of the burner 8 is greater than or equal to a predetermined value, the drain amount in the drain tank 17 is expected to be large. In this case, the CPU opens the electromagnetic valve 45 to allow water to flow through the bypass pipe 38. Thereby, since the amount of water flow of the sub heat exchanger tube 10a of the sub heat exchanger 10 can be reduced, the amount of drain generation in the sub heat exchanger 10 can be reduced effectively. Further, when it is determined that the combustion amount is less than the predetermined value, the drain amount in the drain tank 17 is expected to be small. In this case, the CPU closes the electromagnetic valve 45 in order not to allow water to flow through the bypass pipe 38. As a result, the amount of water flow through the sub heat transfer tube 10a of the sub heat exchanger 10 can be increased, so that the sub heat exchanger 10 can sufficiently recover the latent heat.

  Next, a fourth modification will be described. In the fourth modification, the amount of water passing through the bypass pipe 38 is adjusted according to the set temperature of hot water. As the set temperature of hot water is lower, the amount of drain generated in the auxiliary heat exchanger 10 increases, so the amount of drain in the drain tank 17 increases. In order to use this property, for example, when the set temperature of hot water is determined to be equal to or lower than a predetermined temperature, the amount of drain in the drain tank 17 is expected to be large. In this case, the CPU opens the electromagnetic valve 45 to allow water to flow through the bypass pipe 38. Thereby, since the amount of water flow of the sub heat exchanger tube 10a of the sub heat exchanger 10 can be reduced, the amount of drain generation in the sub heat exchanger 10 can be reduced effectively. Moreover, when the preset temperature of hot water exceeds a predetermined temperature, the amount of drain in the drain tank 17 is expected to be small. In this case, the CPU closes the electromagnetic valve 45 in order not to allow water to flow through the bypass pipe 38. As a result, the amount of water flow through the sub heat transfer tube 10a of the sub heat exchanger 10 can be increased, so that the sub heat exchanger 10 can sufficiently recover the latent heat.

  Next, a fifth modification will be described. In the fifth modification, the amount of water passing through the bypass pipe 38 is adjusted according to the incoming water temperature at the water supply port 24. The lower the incoming water temperature, the greater the amount of drain generated in the auxiliary heat exchanger 10. In order to utilize this property, for example, a water temperature sensor for detecting the incoming water temperature is provided at the water supply port 24 of the appliance 2. The controller 40 receives an output signal from the water temperature sensor, and the CPU determines whether or not the incoming water temperature detected by the water temperature sensor is equal to or higher than a predetermined temperature. When it is determined that the incoming water temperature is lower than the predetermined temperature, the amount of drain generated in the auxiliary heat exchanger 10 is expected to be large. In this case, the CPU opens the electromagnetic valve 45 to allow water to flow through the bypass pipe 38. Thereby, since the amount of water flow of the sub heat exchanger tube 10a of the sub heat exchanger 10 can be reduced, the amount of drain generation in the sub heat exchanger 10 can be reduced effectively. In addition, when it is determined that the incoming water temperature is equal to or higher than the predetermined temperature, the amount of drain generated in the auxiliary heat exchanger 10 is expected to be small. In this case, the CPU closes the electromagnetic valve 45 in order not to allow water to flow through the bypass pipe 38. As a result, the amount of water flow through the sub heat transfer tube 10a of the sub heat exchanger 10 can be increased, so that the sub heat exchanger 10 can sufficiently recover the latent heat.

  Next, a sixth modification will be described. In the sixth modification, the amount of water flow through the bypass pipe 38 is adjusted by the flow rate (inflow amount) of tap water per unit time flowing into the appliance 2 from the water supply port 24. The greater the amount of incoming water per unit time, the greater the amount of drain generated in the auxiliary heat exchanger 10. In order to use this property, a flow rate sensor that measures the amount of water received at regular intervals (for example, 0.2 seconds) is provided at the water supply port 24 of the appliance 2. The controller 40 receives the output signal from the flow sensor, and the CPU determines whether or not the amount of incoming water measured by the flow sensor is greater than or equal to a predetermined flow rate. When it is determined that the amount of incoming water is greater than or equal to the predetermined flow rate, the amount of drain generated in the auxiliary heat exchanger 10 is expected to be large. In this case, the CPU opens the electromagnetic valve 45 to allow water to flow through the bypass pipe 38. Thereby, since the amount of water flow of the sub heat exchanger tube 10a of the sub heat exchanger 10 can be reduced, the amount of drain generation in the sub heat exchanger 10 can be reduced effectively. In addition, when it is determined that the amount of incoming water is less than the predetermined flow rate, the amount of drain generated in the auxiliary heat exchanger 10 is expected to be small. In this case, the CPU closes the electromagnetic valve 45 in order not to allow water to flow through the bypass pipe 38. As a result, the amount of water flow through the sub heat transfer tube 10a of the sub heat exchanger 10 can be increased, so that the sub heat exchanger 10 can sufficiently recover the latent heat.

  Next, a seventh modification will be described. In the seventh modification, the amount of water passing through the bypass pipe 38 is adjusted according to the outside air temperature. The lower the outside air temperature is, the more drain is generated in the auxiliary heat exchanger 10. In order to utilize this property, an outside air temperature sensor for detecting an outside air temperature is provided outside the appliance 2 of the water heater. The controller 40 receives an output signal from the outside air temperature sensor, and the CPU determines whether or not the outside air temperature detected by the outside air temperature sensor is equal to or higher than a predetermined temperature. When it is determined that the outside air temperature is lower than the predetermined temperature, the amount of drain generated in the auxiliary heat exchanger 10 is expected to be large. In this case, the CPU opens the electromagnetic valve 45 to allow water to flow through the bypass pipe 38. Thereby, since the amount of water flow of the sub heat exchanger tube 10a of the sub heat exchanger 10 can be reduced, the amount of drain generation in the sub heat exchanger 10 can be reduced effectively. Further, when it is determined that the outside air temperature is equal to or higher than the predetermined temperature, the amount of drain generated in the auxiliary heat exchanger 10 is expected to be small. In this case, the CPU closes the electromagnetic valve 45 in order not to allow water to flow through the bypass pipe 38. As a result, the amount of water flow through the sub heat transfer tube 10a of the sub heat exchanger 10 can be increased, so that the sub heat exchanger 10 can sufficiently recover the latent heat.

  Next, an eighth modification will be described. In the eighth modification, the amount of water passing through the bypass pipe 38 is adjusted according to the driving time of the drain pump 20 for sucking up and discharging the drain. For example, as the driving time of the drain pump 20 is shorter, the drain flows in despite the drain in the drain tank 17 is not so much discharged, so the amount of drain in the drain tank 17 increases. On the other hand, the longer the drive time of the drain pump 20, the more the drain in the drain tank 17 is discharged, so the drain amount in the drain tank 17 decreases. In order to utilize this property, the controller 40 is provided with a timer. The CPU uses the output from the timer to measure the driving time of the drain pump 20 as “drain discharging time”, and determines whether or not the discharging time is equal to or longer than a predetermined time. When it is determined that the drain discharge time is less than the predetermined time, the CPU opens the electromagnetic valve 45 to allow water to flow through the bypass pipe 38. Thereby, since the amount of water flow of the sub heat exchanger tube 10a of the sub heat exchanger 10 can be reduced, the amount of drain generation in the sub heat exchanger 10 can be reduced effectively. In addition, when it is determined that the drain discharge time is equal to or longer than the predetermined time, it is expected that the amount of drain generated in the auxiliary heat exchanger 10 is small. In this case, the CPU closes the electromagnetic valve 45 in order not to allow water to flow through the bypass pipe 38. As a result, the amount of water flow through the sub heat transfer tube 10a of the sub heat exchanger 10 can be increased, so that the sub heat exchanger 10 can sufficiently recover the latent heat.

  Further, in the first to eighth modifications, the water flow rate of the bypass pipe 38 is controlled based on each element such as the burn time of the burner 8. For example, the drain water level of the drain tank 17 is used using these elements. And the amount of water flow through the bypass pipe 38 may be controlled based on the estimated drain water level.

  In the first to eighth modifications described above, an electric valve that can continuously adjust the flow passage area by driving a motor instead of the electromagnetic valve 45 in order to regulate the water flow rate of the bypass pipe 38. May be provided. When an electric valve is used, the amount of water flow through the bypass pipe 38 can be continuously increased or decreased, so that the amount of drain generation can be controlled more finely.

  The water heater of the present invention is applicable to a water heater in which drain is generated in a heat exchanger.

2 is a side sectional view of the water heater 1. FIG. It is explanatory drawing of the minimum water level (H1) and the upper limit water level (H2) in the drain tank. 3 is a flowchart of drain discharge processing by a controller 40.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hot water heater 2 Apparatus 8 Burner 9 Main heat exchanger 9a Main heat transfer pipe 10 Sub heat exchanger 10a Sub heat transfer pipe 11 Drain pan 13 Drain exhaust pipe 16 Drain exhaust pipe 17 Drain tank 18 Drain exhaust pipe 20 Drain pump 21 Drain exhaust pipe 22 Nozzle 30 First supply pipe 31 Second supply pipe 38 Bypass pipe 40 Controller 45 Solenoid valve 51 Water level sensor 52 Water level sensor

Claims (4)

A burner that burns fuel gas in a combustion chamber provided in the instrument;
A main heat exchanger for recovering sensible heat from the combustion exhaust of the burner and heating the water flow in the first heat transfer tube;
A sub heat exchanger for recovering latent heat from the combustion exhaust gas passing through the main heat exchanger and heating the water flow in the second heat transfer pipe;
A first supply pipe interposed between a water supply port provided in the appliance and an inlet of the second heat transfer pipe;
A second supply pipe interposed between the outlet of the second heat transfer pipe and the inlet of the first heat transfer pipe;
A tank for temporarily storing drain generated in the auxiliary heat exchanger;
Drain discharge means for discharging the drain in the tank out of the appliance;
A bypass pipe interposed between the first supply pipe and the second supply pipe and supplying a part of the water flow of the first supply pipe to the second supply pipe;
A water heater comprising a water flow amount adjusting means for adjusting a water flow amount of the bypass pipe.   The water heater according to claim 1, wherein the water flow amount adjusting means is provided in the bypass pipe. Water level detection means for detecting the drain water level in the tank;
The water heater according to claim 1 or 2, further comprising a water flow rate control unit that controls the water flow rate adjustment unit based on a drain water level detected by the water level detection unit.   Combustion time of the burner, non-burning time of the burner, combustion amount of the burner, set temperature of hot water supplied from the outlet of the appliance, incoming water temperature at the inlet, incoming water per unit time at the inlet The water heater according to claim 1, further comprising a water flow rate control unit that controls the water flow rate adjusting unit according to at least one of a drain discharge time of the outside air temperature and the drain discharge unit.

Images