Latent heat recovery type water heater

Abstract

To provide a latent heat recovery type water heater in which piping for discharging drain water to outside of the device is eliminated.SOLUTION: A latent heat recovery type water heater includes: atomization means 40 for atomizing drain water in a drain water tank 39; an atomization air flow passage 41 through which atomization air atomized by the atomization means 40 passes; a merging section 46 disposed in an air flow passage section 30 downstream of a combustion gas of a secondary heat exchanger 27 and communicated with the atomization air flow passage 41; a branch section 31 disposed in an air flow passage section 30 on a combustion gas upstream side of the merging section 46; an air supply passage 34 communicated with the branch section 31 and an inlet of the atomization air flow passage 41; first opening / closing means 43a capable of opening / closing the atomization air flow passage 41; and a control section 60 that performs combustion control of a combustion section 8, opening / closing control of the first opening / closing means 43a and drive control of the atomization means 40. The control section 60 closes the first opening / closing means 43a during combustion, and opens the first opening / closing means 43a after stop of the combustion to drive the atomization means 40 and a combustion fan 13.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a domestic latent heat recovery type water heater, and more particularly to a latent heat recovery type water heater in which a pipe for draining drain water discharged from a neutralizer to the outside of the apparatus is eliminated.

Background Art

[0002] Conventionally, in a latent heat recovery type water heater, high-temperature combustion gas is cooled by water in a heat receiving pipe in a secondary heat exchanger, and water vapor in the combustion gas becomes acidic condensed water. Therefore, the acidic condensed water is led to a neutralizer, neutralized by a neutralizing agent, and then drained to the outside of the apparatus. Therefore, when replacing from a non-latent heat recovery type water heater to a latent heat recovery type water heater, construction work such as piping work of drainage facilities is sometimes required. Therefore, a latent heat recovery type water heater has been conventionally devised, as shown in Patent Document 1, in which neutralized drain water is atomized by an atomizing means, eliminating the need for construction work such as piping work.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the latent heat recovery type water heater shown in Patent Document 1, the atomized drain water reattaches to the secondary heat exchanger and flows into the neutralizer again. As a result, it is difficult for the drain water to decrease, and when the usage time becomes long, the drain water overflows from the drain water tank.

[0005] The present invention has been made in view of such a background, and an object thereof is to provide a latent heat recovery type water heater in which atomized drain water does not reattach to the secondary heat exchanger and is surely discharged to the outside of the apparatus.

Means for Solving the Problems

[0006] The present invention has been made to achieve the above object. In claim 1, there are provided a housing, a combustion fan for sending air, an air flow path portion through which the blowing air sent by the combustion fan passes, a combustion portion provided in the housing for taking in the blowing air from the combustion fan and burning fuel, a primary heat exchanger for recovering sensible heat from the combustion gas generated in the combustion portion and heating hot water, a secondary heat exchanger for recovering latent heat from the combustion gas that has passed through the primary heat exchanger and heating hot water, a condensate water flow path for guiding the condensate water generated in the secondary heat exchanger, a neutralizer communicating with the condensate water flow path for neutralizing the condensate water, a drain water flow path through which the drain water discharged from the neutralizer passes, a drain water tank communicating with the drain water flow path for storing the drain water, atomizing means for atomizing the drain water in the drain water tank, an atomized air flow path through which the atomized air atomized by the atomizing means passes, a confluence portion arranged in the air flow path portion downstream of the combustion gas of the secondary heat exchanger and communicating with the atomized air flow path, a branch portion arranged in the air flow path portion upstream of the combustion gas from the confluence portion, an air supply path communicating the branch portion with the inlet of the atomized air flow path, first opening / closing means for opening and closing the atomized air flow path, and a control unit for performing combustion control of the combustion portion, opening / closing control of the first opening / closing means, and driving control of the atomizing means. The control unit is characterized in that the first opening / closing means is closed during combustion, and after combustion stops, the first opening / closing means is opened to drive the atomizing means and the combustion fan.

[0007] In claim 2, it is characterized in that second opening / closing means is provided in the air flow path portion between the confluence portion and the branch portion and capable of opening and closing the air flow path portion forming a parallel with the atomized air flow path.

[0008] In claim 3, it is characterized in that a damper integrating the first opening / closing means and the second opening / closing means is provided at the confluence portion or the branch portion.

[0009] In claim 4, the atomizing means is characterized in that the drain water is atomized by ultrasonic vibration.

[0010] In claim 5, a Venturi tube type flow path is provided in the atomizing air flow path, and the atomizing means is characterized in that the drain water is sprayed into the Venturi tube type flow path.

Advantages of the Invention

[0011] According to claim 1 of the present invention, since the atomized drain water does not reattach to the secondary heat exchanger, the drain water can be efficiently and reliably discharged.

[0012] Further, since the atomization of the drain water is performed inside the housing without providing a spray port at the exhaust outlet of the water heater to spray the drain water, there is no possibility of soiling the appearance of the housing of the water heater due to dripping of the drain water, and it can be used in a good state for a long time.

[0013] Further, since the first opening / closing means is arranged in the atomizing air flow path and the combustion gas at a high temperature (for example, 60°C) during combustion does not flow into the neutralizer (for example, made of resin) or the drain water tank during combustion, there is no risk of damaging the neutralizer or the drain water tank by heat, and it can be used in a good state for a long time.

[0014] Further, since the atomizing air flow path is blocked by the first opening / closing means among the two paths from the branch portion to the confluence portion, it is not necessary to blow air through the two paths simultaneously during combustion, and it is not necessary to increase the rotational speed to increase the air volume of the combustion fan, and the generation of noise during combustion can be suppressed.

[0015] Further, according to claim 2, when discharging the atomized air, the second opening / closing means for closing the air flow path portion (hereinafter referred to as the combustion exhaust path) provided in the air flow path portion between the confluence portion and the branch portion and forming a parallel with the atomizing air flow path is configured, so that air flows efficiently through the atomizing air flow path, and the atomized air can be efficiently discharged outside the device.

[0016] Further, according to claim 3, since the first opening / closing means of the atomizing air flow path and the second opening / closing means of the air flow path portion are realized by one damper, the structure can be simplified and the number of parts can be reduced, so that the manufacturing cost can be suppressed.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0018] The first embodiment of the latent heat recovery type water heater according to the present invention will be described with reference to FIG. 1.

[0019] 1 is a latent heat recovery type water heater according to the first embodiment, and is a water heater provided with a combustion section 8 that forms a flame downward. Specifically, 13 is a combustion fan, and the blown air sent from the combustion fan 13 passes through the air flow path section 30 and is discharged from the exhaust outlet 49. The air flow path section 30 is provided with a combustion section 8, a combustion chamber 19, a primary heat exchanger 25, a muffler 50, a secondary heat exchanger 27, a branch section 31, a combustion exhaust path 35, a dew condensation water flow path 32, a drain water flow path 38, an atomized air flow path 41, and a confluence section 46, which will be described later.

[0020] The combustion section 8 burns fuel oil such as petroleum, and 9 is a fuel pump that pumps fuel oil to the combustion section 8 via a fuel supply pipe 10. The primary air and secondary air burned in the combustion section 8 are supplied by the combustion fan 13.

[0021] A primary heat exchanger 25 is disposed on the downstream side of the combustion gas of the combustion section 8, and a secondary heat exchanger 27 is disposed downstream of the primary heat exchanger 25. The combustion gas that has passed through the primary heat exchanger 25 and the secondary heat exchanger 27 in sequence is exhausted outside the latent heat recovery type water heater 1 from the exhaust outlet 49 via the combustion exhaust passage 35 and the confluence section 46.

[0022] The primary heat exchanger 25 is a sensible heat exchanger housed in the combustion chamber 19, and is configured in a fin-tube type that recovers sensible heat from the combustion gas generated by the combustion of the combustion section 8 and heats the fluid to be heated flowing through the primary heat receiving pipe 24.

[0023] The secondary heat exchanger 27 recovers latent heat from the combustion gas after passing through the primary heat exchanger 25 and heats the fluid to be heated flowing through the heat receiving pipe 26. Below the secondary heat exchanger 27, an inclined bottom plate 29 is provided to guide the condensed water generated on the surface of the heat receiving pipe 26 and dripping down. The bottom plate 29 guides the condensed water to the branch section 31 provided below the secondary heat exchanger 27 and guides it to the condensate water flow path 32.

[0024] The condensed water guided by the bottom plate 29 is neutralized by a neutralizer 37 provided with a neutralizing agent mainly composed of calcium carbonate through the condensate water flow path 32 communicating with the condensate water flow path 32, and is stored in a drain water tank 39 communicating with the drain water flow path 38 via the drain water flow path 38.

[0025] The drain water tank 39 is provided with atomizing means 40 that is signal-connected to a control unit 60 described later. The atomizing means 40 atomizes the drain water stored in the drain water tank 39. An atomizing air flow path 41 is provided between the drain water tank 39 and the confluence section 46. The atomizing air flow path 41 is provided with a damper chamber 42. The damper chamber 42 is provided with a damper 43a which is a first opening and closing means that opens and closes about a drive shaft 45 and can open and close the atomizing air flow path 41. The damper 43a is opened and closed by the drive of a damper motor 44 that is signal-connected to the control unit 60.

[0026] The atomized air atomized by the atomizing means 40 is exhausted to the outside of the apparatus from the exhaust outlet 49 through the atomizing air flow path 41, the opened damper 43a, and the confluence part 46 by the driving of the combustion fan 13.

[0027] Thereby, the flow of air (the first path) from the silencer 50 to the secondary heat exchanger 27, the combustion exhaust path 35, the confluence part 46, the air flow path part 30, and then to the exhaust outlet 49, and the flow of air (the second path) from the silencer 50 through the branch part 31 to the dew condensation water flow path 32 and the drain water flow path 38 which are the air supply path 34, the atomizing air flow path 41, the damper 43a, the confluence part 46, the air flow path part 30, and then to the exhaust outlet 49 are formed.

[0028] The atomizing means 40 is configured to include an ultrasonic vibrator and atomize drain water by ultrasonic vibration.

[0029] As shown in FIG. 2, the control unit 60 is a microcomputer including a combustion control unit 62 that controls the combustion of the combustion unit 8 by controlling the driving of the combustion fan 13 and the fuel pump 9, an opening / closing control unit 61 that controls the opening and closing of the damper motor 44, and an atomizing control unit 63 that controls the driving of the atomizing means 40. On the input side, a flow rate sensor 23 of the water supply pipe 21 is connected, and on the output side, a spark plug (not shown) provided in the combustion unit 8, the combustion fan 13, the fuel pump 9, and the damper motor 44 are connected. Further, the control unit 60 and the operation unit 71 are communicably connected.

[0030] Next, the operation of the first embodiment will be described.

[0031] When a hot water tap (not shown) communicating with the hot water supply pipe 22 is opened and the flow rate sensor 23 detects the flow of the fluid to be heated, the control unit 60 causes the spark plug (not shown) to discharge, and the fuel oil is ignited in the combustion unit 8 by the driving of the fuel pump 9, and the combustion is started by the driving of the combustion fan 13. When the combustion is started, the fuel supply of the required spray fuel amount according to the required calorific value by the fuel pump 9 and an oil ratio valve (not shown) and the combustion fan 13 form a combustion flame in the combustion unit 8 while maintaining an appropriate air-fuel ratio.

[0032] The combustion gas generated by combustion heats the primary heat receiving tubes 24 of the primary heat exchanger 25 to heat the fluid to be heated flowing through the primary heat receiving tubes 24. After passing through the primary heat exchanger 25, the combustion gas recovers the latent heat from the combustion gas and heats the fluid to be heated flowing through the heat receiving tubes 26. The combustion gas that has passed through the primary heat exchanger 25 and the secondary heat exchanger 27 in sequence is exhausted outside the latent heat recovery type water heater 1 from the exhaust outlet 49 via the confluence part 46 with the combustion exhaust passage 35.

[0033] The condensed water generated on the surface of the heat receiving tubes 26 of the secondary heat exchanger 27 during combustion drips and is guided by the inclined bottom plate 29 to the condensate water flow path 32, where it is neutralized by the neutralizer 37 provided with a neutralizing agent mainly composed of calcium carbonate, and is stored in the drain water tank 39 via the drain water flow path 38.

[0034] Based on FIG. 3, the operation of this embodiment will be described.

[0035] In step S1, before the combustion of the combustion part 8 starts, the control unit 60 closes the damper 43a so that the combustion gas does not flow into the atomization air flow path 41. When combustion starts in step S2, drain water is stored in the drain water tank 39 as described above. After combustion stops, when it is confirmed in step S3 that combustion has stopped, the drain water in the drain water tank 39 stored during combustion is discharged outside the device in the subsequent steps.

[0036] In step S4, the timer count is reset, and in step S5, the damper 43a is opened to open the atomization air flow path 41. In step S6, the atomization means 40 is driven to start atomizing the drain water in the drain water tank 39, and in step S7, the combustion fan 13 is driven.

[0037] In step S8, when the timer count has elapsed for a predetermined time (a time sufficient for the drain water in the drain water tank 39 to run out, for example, 1 hour), in step S9, the atomization means 40 is stopped, and in step S10, the combustion fan 13 is stopped.

[0038] As a result, the atomized drain water can be efficiently and surely discharged without reattaching to the secondary heat exchanger 27. Further, a damper 43a, which is a first opening / closing means, is arranged in the atomizing air flow path 41. During combustion, the high-temperature (e.g., 60°C) combustion gas during combustion does not flow into the neutralizer 37 (e.g., made of resin) or the drain water tank 39. Therefore, there is no risk of damaging the neutralizer 37 and the drain water tank 39 by heat, and they can be used in good condition for a long time. In addition, in order to block the atomizing air flow path 41, which is the second path, out of the first path and the second path of the path from the branch portion 31 to the confluence portion 46 with the damper 43a, which is the first opening / closing means, it is not necessary to blow air through the first path and the second path simultaneously during combustion, and it is not necessary to increase the rotational speed to increase the air volume of the combustion fan 13. Therefore, the generation of noise during combustion can be suppressed.

[0039] In step S8, the atomizing means 40 is driven for a predetermined time. However, a water level detection means (e.g., a float and a microswitch or a water level electrode) capable of detecting the water level of the drain water in the drain water tank 39 may be provided, and the atomizing means 40 may be stopped when the drain water runs out.

[0040] Next, a second embodiment will be described with reference to FIG. 4. In each figure, the same reference numerals are given to common components and components of the same type, and their overlapping descriptions are appropriately omitted.

[0041] Reference numeral 200 denotes a latent heat recovery type water heater according to the second embodiment, which is a water heater provided with a combustion section 8 that forms an upward flame. Reference numeral 33 denotes a U-shaped pipe 33 provided for sending the condensed water generated in the secondary heat exchanger 27 and collected by the bottom plate 29 to the condensate flow path 32. The U shape forms a water seal state that can prevent the passage of combustion gas through the path.

[0042] On the downstream side of the exhaust gas of the secondary heat exchanger 27, at a position upstream of the confluence portion 46, there are provided a branch portion 31, a damper 43b in which a second opening / closing means capable of opening and closing the combustion exhaust path 35 between the confluence portion 46 and the branch portion 31 and a first opening / closing means capable of opening and closing the atomizing air flow path 41 are integrated. And it includes an air supply passage 34 that communicates the branch portion 31 with the inlet of the atomization air passage 41.

[0043] When the integrated damper 43b is on one side, the atomization air passage 41 is in a closed state, and the combustion exhaust passage 35 between the confluence portion 46 and the branch portion 31 is in an open state. When the damper 43b is on the other side, the atomization air passage 41 is in an open state, and the combustion exhaust passage 35 between the confluence portion 46 and the branch portion 31 is in a closed state.

[0044] Accordingly, the air from the combustion fan 13 is exhausted from the exhaust outlet 49 through the open combustion exhaust passage 35 when the atomization air passage 41 corresponding to step S1 in FIG. 3 is closed and in a blocked state, and is exhausted from the exhaust outlet 49 through the atomization air passage 41 together with the atomized air vaporized by the atomization means 40 when the atomization air passage 41 corresponding to step S5 in FIG. 3 is opened and in an open state.

[0045] Note that although the branch portion 31 is provided on the downstream side of the exhaust gas from the secondary heat exchanger 27, it may be provided near the outlet of the combustion fan 13 upstream of the secondary heat exchanger 27.

[0046] Next, a third embodiment will be described with reference to FIG. 5.

[0047] Reference numeral 300 denotes a latent heat recovery type water heater according to the third embodiment, which is a water heater including a combustion unit 8 that forms an upward flame. The difference from the latent heat recovery type water heater 200 of the second embodiment is that the branch portion 31 is provided with second opening and closing means capable of opening and closing the combustion exhaust passage 35 between the confluence portion 46 and the branch portion 31, the air supply passage 34 is provided with first opening and closing means capable of substantially opening and closing the atomization air passage 41, and a damper 43c in which the first opening and closing means and the second opening and closing means are integrated.

[0048] As a result, when the atomizing air passage 41 corresponding to step S1 in FIG. 3 is closed and in a blocked state, the air of the combustion fan 13 is exhausted from the exhaust outlet 49 through the open combustion exhaust passage 35. When the atomizing air passage 41 corresponding to step S5 in FIG. 3 is opened and in an open state, it is exhausted from the exhaust outlet 49 together with the atomized air vaporized by the atomizing means 40 through the atomizing air passage 41.

[0049] The embodiment is not limited to the above. For example, it may be embodied as shown in FIG. 6.

[0050] 400 is a latent heat recovery type water heater of the fourth embodiment, which is a water heater provided with a combustion section 8 that forms an upward flame. The difference from the latent heat recovery type water heater 200 of the second embodiment is that the atomizing air passage 41 is provided with a Venturi tube type passage 51, and the atomizing means 40 is provided with an atomizing pump 52 that sprays the drain water of the drain water tank 39 into the Venturi tube type passage 51. As a result, the atomizing means 40 for the drain water may be an ultrasonic method or a Venturi tube method, and the selection may be appropriately determined by the designer.

[0051] As a result, the atomized drain water does not reattach to the secondary heat exchanger 27, so that the drain water can be efficiently and reliably discharged.

[0052] In addition, since the atomization of the drain water is performed inside the housing 2 without providing a spray port for atomization at the exhaust outlet 49 to spray the drain water, there is no risk of soiling the appearance of the housing 2 due to dripping of the drain water, and it can be used in a good state for a long time. In addition, dampers 43a, 43b, or 43c, which are the first opening and closing means, are arranged in the atomizing air passage 41 so that high-temperature (e.g., 60°C) combustion gas during combustion does not flow into the neutralizer 37 (e.g., made of resin) or the drain water tank 39 during combustion. Therefore, there is no risk of damaging the neutralizer 37 or the drain water tank 39 by heat, and it can be used in a good state for a long time. Also, since the atomizing air flow path 41 among the two paths of the combustion exhaust path 35 and the atomizing air flow path 41 from the branch portion 31 to the confluence portion 46 is blocked by the damper 43a or 43b or 43c which is the first opening / closing means, it is not necessary to blow air through the two paths simultaneously during combustion, and it is not necessary to increase the rotational speed to increase the air volume of the combustion fan 13, and the generation of noise during combustion can be suppressed.

[0053] Also, when discharging the atomizing air, since the damper 43b or 43c which is the second opening / closing means for blocking the combustion exhaust path 35 is configured, air can flow efficiently through the atomizing air flow path 41, and the atomizing air can be discharged outside the apparatus efficiently. Also, since the first opening / closing means of the atomizing air flow path 41 and the second opening / closing means of the combustion exhaust path 35 are realized by one damper 43b or 43c, the structure can be simplified, the number of parts can be reduced, and thus the manufacturing cost can be suppressed.

[0054] Note that although the control unit 60 was described as closing the damper 43a before the start of combustion of the combustion unit 8 and blocking the atomizing air flow path 41 during combustion in step S1, it may be opened temporarily during combustion.

[0055] Note that the other configurations used in this embodiment are presented as an example and are not intended to limit the scope of the invention, and it can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and its equivalent scope.

Explanation of Reference Numerals

[0056] 1, 200, 300, 400: Latent heat recovery type water heater 2: Housing 8: Combustion unit 13: Combustion fan 25: Primary heat exchanger 27: Secondary heat exchanger 30: Air flow path section 31: Branch portion 32: Condensation water flow path 34: Air supply path 37: Neutralizer 38: Drain water flow path 39: Drain water tank 40: Atomizing means 41: Atomizing air flow path 43a, 43b, 43c: Damper 46: Confluence part 51: Venturi tube type flow path 60: Control unit

Claims

1. A housing, a combustion fan for sending air, an air flow path portion through which the blown air sent by the combustion fan passes, a combustion portion that is within the housing, takes in the blown air from the combustion fan, and burns fuel, a primary heat exchanger that recovers sensible heat from the combustion gas generated in the combustion portion and heats hot water, a secondary heat exchanger that recovers latent heat from the combustion gas that has passed through the primary heat exchanger and heats hot water, a condensate water flow path that guides the condensate water generated in the secondary heat exchanger, a neutralizer that communicates with the condensate water flow path and neutralizes the condensate water, a drain water flow path through which the drain water discharged from the neutralizer passes, a drain water tank that communicates with the drain water flow path and stores the drain water, atomizing means for atomizing the drain water in the drain water tank, an atomized air flow path through which the atomized air atomized by the atomizing means passes, a merging portion that is arranged in the air flow path portion downstream of the combustion gas of the secondary heat exchanger and communicates with the atomized air flow path, a branching portion that is arranged in the air flow path portion upstream of the combustion gas from the merging portion, an air supply path that communicates the branching portion with the inlet of the atomized air flow path, first opening / closing means for opening and closing the atomized air flow path, a control unit that performs combustion control of the combustion portion, opening / closing control of the first opening / closing means, and drive control of the atomizing means, comprising: The control unit: closes the first opening / closing means during combustion, and after combustion stops, opens the first opening / closing means to drive the atomizing means and the combustion fan. A latent heat recovery type water heater characterized by the above.

2. A latent heat recovery type water heater according to claim 1, further comprising second opening / closing means that is provided in the air flow path portion between the merging portion and the branching portion and is capable of opening and closing the air flow path portion that forms a parallel with the atomized air flow path.

3. A latent heat recovery type water heater according to claim 2, further comprising a damper that integrates the first opening / closing means and the second opening / closing means and is provided at the merging portion or the branching portion.

4. The atomizing means atomizes the drain water by ultrasonic vibration. A latent heat recovery type water heater according to any one of claims 1 to 3.

5. A venturi tube type flow path is provided in the atomized air flow path. The atomizing means sprays the drain water into the venturi tube type flow path. A latent heat recovery type water heater according to any one of claims 1 to 3. ​ ​

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