JP5157644B2 - Latent heat recovery water heater - Google Patents

Description

  The present invention relates to a latent heat recovery hot water supply in which drain water generated in a heat exchanger for latent heat recovery is subjected to a detoxification process such as a reforming process and / or a neutralization process, and the treated water after the process is drained. Related to the machine.

  The latent heat recovery water heater is also called a so-called high-efficiency water heater or condensing water heater. When heating the incoming water by sensible heat of combustion heat to supply hot water, the latent heat of the combustion exhaust gas after heating the incoming water It is a hot water supply device designed to increase the efficiency of heat utilization by further recovering. Here, condensing means condensation, and the condensation heat (latent heat) is recovered by condensing water vapor contained in the combustion exhaust gas.

  As this type of latent heat recovery hot water supply apparatus, conventionally, in order to neutralize the drain water generated in the heat exchanger for recovering latent heat, two types of neutralization tanks are provided in series with respect to the drain water outlet path. It is known (see, for example, Patent Document 1). In this, a neutralizing agent having a predetermined pH adjusting function is incorporated in the first neutralizing tank on the upstream side, and the neutralizing agent incorporated in the first neutralizing tank in the second neutralizing tank on the downstream side, Has a built-in neutralizer having a pH adjustment function of different values, and drain water derived from the heat exchanger can directly flow into the second neutralization tank by bypassing the first neutralization tank. I am doing so.

  In addition, drain water is introduced into the neutralization tank filled with the neutralizing agent through the introduction pipe, while it is introduced into the neutralization tank with respect to the neutralized treated water that passes through the neutralization tank and is drained by the drain pipe. There is also known one provided with a bypass pipe that branches from the introduction pipe and joins the drain pipe from the neutralization tank so that the previous drain water can be mixed (see, for example, Patent Document 2).

JP 2001-54794 A JP 2000-107771 A

  By the way, the exhaust gas after the latent heat has been recovered by passing through the latent heat recovery heat exchanger is released from the exhaust top (exhaust port) to the outside of the machine. Depending on the installation conditions of the latent heat recovery water heater, There is a case where the exhaust top is installed so as to open facing the external space outside. In such a case, if it rains, the opening of the exhaust top will be exposed to wind and rain, and there is a possibility of inconvenience.

  That is, during combustion operation for hot water supply etc., exhaust pressure from the blower fan acts on the opening of the exhaust top from the inside of the machine to the outside of the machine. If the operation is stopped, rainwater may enter from the opening of the exhaust top into the latent heat recovery heat exchanger. Such intrusion may be caused not only by the inflow of rainwater, but also by the inundation of seawater due to waves or the like in the coastal area, or when it is accidentally sprayed when watering the garden trees. Hereinafter, the above-mentioned water such as rainwater that may be blown into the latent heat recovery heat exchanger from the opening of the exhaust top is collectively referred to as “rainwater”.

  On the other hand, it is considered by the applicant of the present invention to use the treated water after the treatment by performing a reforming treatment for removing formaldehyde from the drain water in addition to the neutralization treatment for the drain water. . In this case, since a reforming tank is added as a drain water treatment tank in addition to the neutralization processing tank, the volume of the reforming tank is the smallest within the range that satisfies the performance requirements from the demand for downsizing of the latent heat recovery water heater. It will be set to the limit.

  Under such circumstances, when the latent heat recovery water heater is continuously operated in the maximum combustion operation and a relatively large amount of drain water is generated, the operation is stopped, and in the case of intrusion of rainwater or the like immediately after that, It is assumed that there will be a situation in which rainwater or the like is mixed in and introduced into the reforming tank or neutralization tank in an increased state.

  For this reason, when the volume of the drain water treatment tank such as the reforming tank or the neutralization treatment tank is set in consideration of the occurrence of such an assumed situation, the volume of the drain water treatment tank becomes relatively large. It also becomes a hindrance to the request for downsizing of the entire latent heat recovery water heater. In other words, even if rainwater has already entered the reforming tank that is almost full of drain water, in order to prevent the drain water from being pushed downstream by the intruding water, the reforming tank is taken into consideration Therefore, it is against the request for downsizing. In addition, due to the intrusion water, there is a possibility of causing poisoning and consumption of the modifying material for the reforming treatment and the neutralizing agent for the neutralizing treatment.

  The present invention has been made in view of such circumstances, and the object of the present invention is to improve the efficiency of drain water treatment in consideration of intrusion / mixing of rainwater, etc. An object of the present invention is to provide a latent heat recovery water heater capable of avoiding a situation where the capacity of a processing agent is reduced.

  In order to achieve the above object, according to a first aspect of the latent heat recovery water heater, a sensible heat recovery heat exchanger that recovers sensible heat from combustion gas generated by combustion of a burner, and this sensible heat recovery heat exchange Latent heat recovery heat exchanger for recovering latent heat from flue gas after passing through the vessel, and a drain water collection drain for collecting and draining drain water generated in the latent heat recovery heat exchanger The following specific items were prepared for the recovery hot water supply system. That is, a drain water treatment unit interposed in the middle of the drain water collection drainage channel, and a branch water treatment unit branched from the drain water collection drainage channel located upstream from the drain water treatment unit, bypassing the drain water treatment unit and downstream A bypass channel that joins the drain water collection and drainage channel at the side position, and a drain water collection and drainage channel at a position where this bypass channel branches, and the channel is either the drain water treatment unit side or the bypass channel side The flow path switching means for switching to any one of the above and the flow path switching means to the bypass flow path side is controlled so that intruded water that has entered the latent heat recovery heat exchanger from the outside is not supplied to the drain water treatment section. And a control means (claim 1).

  In the case of the first invention, when the flow path switching means is switched to the drain water treatment section side by the control means, the drain water generated in the latent heat recovery heat exchanger by the combustion operation is drained. When the flow path switching means is controlled to be switched to the bypass flow path side by the control means, the flow from the latent heat recovery heat exchanger is the drain water treatment section. Without being supplied to the water, it is guided to the downstream side of the drain water treatment section through the bypass flow path. Therefore, even if rainwater or the like enters the latent heat recovery heat exchanger from the outside, the intrusion water such as rainwater (hereinafter simply referred to as “intrusion water” in this specification) is drained from the latent heat recovery heat exchanger. Instead of being supplied to the water treatment unit, the drain water treatment unit is bypassed and guided to the downstream side. As a result, there is no inconvenience such as the drain water treatment part being worn out by the intrusion water, leading to a decrease in capacity, and the drain water treatment part volume can be set without considering the intrusion water. It does not impair the request for conversion.

  In the first aspect of the present invention, when the burner is in a non-combustion operation state and the drain heat is not substantially generated in the latent heat recovery heat exchanger, the flow path switching means is connected to the bypass flow path side. It is possible to adopt a configuration in which the flow path switching control is performed. By doing so, it is possible to perform flow path switching control so that the intrusion water from the latent heat recovery heat exchanger is not reliably supplied to the drain water treatment unit. That is, by switching to the bypass channel side uniformly during a period when rainwater or the like may enter, it is possible to prevent the intrusion water from being reliably supplied to the drain water treatment unit.

  In the second invention relating to the latent heat recovery water heater, the sensible heat recovery heat exchanger that recovers sensible heat from the combustion gas generated by the combustion of the burner, and the combustion exhaust gas after passing through the sensible heat recovery heat exchanger A latent heat recovery water heater that includes a latent heat recovery heat exchanger that recovers latent heat from the water and a drain water collection and drainage channel that collects and drains drain water generated in the latent heat recovery heat exchanger, The following specific matters were prepared. That is, a drain water treatment unit interposed in the middle of the drain water collection drainage channel, and a branch water treatment unit branched from the drain water collection drainage channel located upstream from the drain water treatment unit, bypassing the drain water treatment unit and downstream A bypass channel that joins the drain water collection and drainage channel at the side position, and a drain water collection and drainage channel at a position where this bypass channel branches, and the channel is either the drain water treatment unit side or the bypass channel side A flow path switching means for switching to any one of the above, a tank interposed in a drain water collection / drainage channel located upstream of the flow path switching means, and a water detection means for detecting the presence of water in the tank, Control means for controlling flow path switching by the flow path switching means. And as said control means, it was set as the structure which performs flow-path switching control based on the output of the water detection signal by the said water detection means, and the combustion operation state of the said burner (Claim 3).

  In the case of the second aspect of the invention, when the burner is in the combustion operation state, drain water is generated in the latent heat recovery heat exchanger, but rain water or the like does not enter from the latent heat recovery heat exchanger. The flow path switching means is switched to the drain water treatment section side by the control means, whereby the drain water guided through the drain water collection and drainage channel is processed in the drain water treatment section. On the other hand, when the burner is in a non-combustion operation state, there is a possibility of intrusion of rainwater, etc. from the latent heat recovery heat exchanger, but there is no generation of drain water, so water detection that there is water in the tank When the signal is output from the water detection means, it is determined that the water is intrusion water, and the flow path switching means is switched to the bypass flow path side by the control means. Thereby, intrusion water can be reliably prevented from being supplied to the drain water treatment unit.

  In the above-described latent heat recovery water heater, as the drain water treatment unit, either a reformer that removes harmful substances contained in the drain water and reforms, and a neutralizer that neutralizes the drain water or (Claim 4) Further, the drain water collecting and drainage channel is provided with a sterilizing device for sterilizing the drain water, and the downstream end of the bypass channel is positioned upstream of the sterilizing device. It can connect so that it may join to this drain water collection drainage channel (Claim 5). When the flow path switching means is switched to the bypass flow path side by the control means, the intruding water bypasses the drain water treatment section and is introduced into the sterilizer. As a result, even if the intruding water contains microorganisms, the microorganisms can be sterilized to avoid the propagation of microorganisms.

  As described above, according to the latent heat recovery hot water supply device of any one of claims 1 to 5, rainwater from the latent heat recovery heat exchanger side is controlled by the flow path switching control of the flow path switching means by the control means. Even if the water enters, the intrusion water can be prevented from being supplied to the drain water treatment unit and can be led to the downstream side of the drain water treatment unit. Accordingly, it is possible to prevent the occurrence of inconveniences such as the drain water treatment unit being worn out by the intrusion water and causing a decrease in capacity, and the volume setting of the drain water treatment unit can be performed without considering the intrusion water. Thus, the entire latent heat recovery water heater can be made compact.

  In particular, according to claim 2, by switching to the bypass channel side uniformly during a period in which rainwater or the like may enter, it is ensured that the intrusion water is not supplied to the drain water treatment unit. be able to.

  According to the latent heat recovery hot water supply apparatus of the third aspect, it is possible to accurately determine whether or not rainwater or the like has entered, and to more reliably perform the bypass of the intruding water.

  According to claim 4, the invention can be embodied by specifically specifying the configuration of the drain water treatment unit, and according to claim 5, even if microorganisms are included in the intrusion water The microorganisms can be sterilized to avoid the propagation of microorganisms.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<First Embodiment>
FIG. 1 shows a main part of a latent heat recovery water heater E according to an embodiment of the present invention, 1 is a secondary heat exchanger as a heat exchanger for latent heat recovery, 2 is a bathtub, 3 is a recuperation of bathtub water. The recirculation circuit 5 for carrying out is a reformer that removes formaldehyde (HCHO), which is a harmful substance contained in the drain water, from the drain water derived from the secondary heat exchanger 1 and performs a reforming process. A reforming tank, 6 is a sterilizing apparatus for sterilizing and neutralizing drain water after the reforming process in the reforming tank 5, and a neutralizing tank as a neutralizing apparatus, and 7 is a sheet after the reforming process and the neutralizing process. A buffer tank for temporarily storing the treated drain water, 8 is a switching valve as a flow path switching means. In the present embodiment, the drain water generated in the secondary heat exchanger 1 is subjected to a reforming process in the reforming tank 5 and a neutralizing process in the neutralizing tank 6 after the reforming process, or in addition to sterilization. After the drain water treatment is performed, the treated drain water is discharged into the tub 2 through the external piping 30 outside the machine for recirculation circulation by flowing the treated drain water into the recirculation circuit 3. Show. The treated drain water discharged into the bathtub 2 is drained from the drain port 20 to the general drainage facility 22, and the treated drain water that has undergone the above-described reforming treatment and neutralization treatment is sufficiently purified. Therefore, it can be handled according to the convenience of the user, such as storing it as it is without draining and reusing it as bathtub water, or reusing it as intermediate water for washing the bathtub. The drain water treatment unit of the present invention is configured by the reforming tank 5 or by both the reforming tank 5 and the neutralization tank 6. In addition, latent heat recovery is performed by the reheating circulation path 3 provided in the interior of the latent heat recovery water heater E and the external piping 30 connected to the recirculation circulation path 3 at the connection portions 300a and 300b and installed outside the apparatus. A recirculation circuit that circulates the bath water for reheating between the water heater E and the bathtub 2 is configured.

  The secondary heat exchanger 1 includes a heat exchanger case 11 and a heat exchanger main body 12 such as a multi-tube type disposed in the heat exchanger case 11. The flue gas supplied through the flue gas passage 10 to the secondary heat exchanger 1 flows into the inside from the inlet 111 at one side position (left side position in the figure) of the heat exchanger case 11, and the other side position. After flowing toward the outlet 112 (right side position in the figure), it is discharged out of the machine from the outlet 112 constituting the exhaust top. Then, while the combustion exhaust gas flows from the upstream inlet 111 side to the downstream outlet 112 side, it comes into contact with the outer wall of the heat exchanger body 12 through which cold water enters, and is included in the combustion exhaust gas. The condensed water vapor condenses, and the condensed water droplets (drain water) D are collected along the upper surface of the drain pan (drain receiving portion) 11a constituted by the inner surface of the bottom plate 113 of the heat exchanger case 11, The drain water thus made flows into the reforming tank 5 through the outlet pipe 13. The drain pan 11a, the outlet pipe 13, and the outlet pipes 14, 15, and 16 described later constitute a drain water collecting and draining channel for collecting and draining drain water.

  The drain pan 11a is formed as an inclined surface having a downward slope from the upstream inlet 111 side toward the downstream outlet 112 side, and is formed on the bottom plate 113 in the vicinity of the outlet 112 which is the lowest position of the inclined surface. On the other hand, it connects so that the upstream end of the outlet tube 13 may open. As a result, drain water that has fallen from the outer surface of the heat exchanger main body 12 to the drain pan 11a is guided to the upstream opening end 131 of the drain water outlet pipe 13 by the gravity action and collected along the inclined surface. ing. Conversely, the drain pan may be formed on an inclined surface having a downward slope from the outlet 112 side toward the inlet 111 side, and the upstream end of the outlet pipe 13 may be opened near the inlet 111 side.

The reforming tank 5 is filled with a modifying material containing manganese dioxide (MnO ₂ ) as a main component, and is brought into contact with the modifying material while drain water is flowing from one end to the other end. Formaldehyde contained in the drain water is removed (decomposed and removed) by a decomposition reaction using the catalyst as a catalyst. For example, one or a plurality of columns 51 (five in the example of FIG. 1) filled with the modifying material may be arranged in a row, and the drain water may be sequentially flowed in the vertical direction. At this time, the inside of each column 51 is continuously caused to flow by the extrusion pressure (extruding flow method) of drain water led out through the outlet pipe 13, so that the power of the pump or the like is unnecessary. it can.

  The manganese dioxide catalyst as the reforming material may be of various properties such as a powder catalyst, a granulated product catalyst (pellet catalyst), and a honeycomb catalyst. The granulated catalyst is formed by mixing manganese dioxide and a binder (for example, silica or alumina) into porous pellets. The honeycomb catalyst is coated with manganese dioxide on a honeycomb-shaped carrier and the surface is coated. It is carried on. From the viewpoint of contact with drain water, a porous pellet catalyst is most effective. Here, manganese dioxide has α-type, β-type, and γ-type crystal structures. However, γ-type is excellent in formaldehyde decomposition / removal ability or short-time treatment ability, and in particular, BET value (specific surface area value). Higher is more preferable because it shows higher ability.

Then, by the oxidative decomposition reaction (HCHO → H ₂ O + CO ₂ ) by the manganese dioxide catalyst in the reforming tank 5, almost all the formaldehyde contained in the drain water usually at a concentration of about 10 ppm is removed (HCHO concentration 0. It is set so that it can be detoxified by removal until it becomes 01 ppm or less. That is, the selection of the manganese dioxide catalyst as described above, the setting of the contact time (treatment time) between the drain water and the modifier by setting the number and length of the column 51, and the treated water as described later. By setting the temperature condition of a certain drain water, almost the entire amount of formaldehyde can be removed within a short processing time that can be put to practical use.

  The neutralization tank 6 is filled with a neutralizing agent (for example, calcium carbonate). In the neutralization tank 6, the drain water after the reforming process (formaldehyde removal process) in the reforming tank 5 is introduced from the inlet of the neutralization tank 6 through the lead-out pipe 14, and the drain water that has flowed in flows to the outlet. In the meantime, it is neutralized by contacting with the neutralizing agent, and the drain water after the neutralization treatment is supplied to the buffer tank 7 through the outlet pipe 15. The neutralization tank 6 has a sterilization means 61 as a sterilizer on the inflow side of the drain water from the outlet pipe 14, and has a sterilization function for general bacteria in addition to the neutralization function. It is configured. As the sterilizing means 61, for example, a sterilizing agent such as a silver tablet is provided and sterilized by contact between the sterilizing agent and drain water, or a heater is provided. What is necessary is just to comprise. Note that the sterilization means 61 may be installed separately from the neutralization tank 6.

  The buffer tank 7 has a predetermined internal volume, and drain water that has undergone the above-described reforming treatment and sterilization / neutralization treatment is introduced through the outlet pipe 15 and temporarily stored therein. And, the downstream end of the outlet pipe 16 whose upstream end is connected to the buffer tank 7 is connected to the recirculation circulation path 3 (in the illustrated example, the forward path 3b) via a three-way switching valve 17 as switching means. The three-way switching valve 17 is switched at a predetermined timing by a controller 26 as a control means, and drain water in the buffer tank 7 is led out to the recirculation circuit 3, and enters the bathtub 2 through the recirculation circuit 3 and the external piping 30. It is supposed to be discharged. When the latent heat recovery water heater E is installed on the first floor and the bathtub is also installed on the first floor, the discharge to the bathtub 2 is a drop based on the gravity action based on the height relationship between the buffer tank 7 and the bathtub 2 If the latent heat recovery water heater E is installed on the first floor and the bathtub 2 is installed on the second floor, for example, a pump (not shown) interposed in the outlet pipe 16 is operated. This can be done by doing so.

  The three-way switching valve 17 is normally closed on the outlet pipe 16 side to keep the recirculation circuit 3 (outward path 3b) in communication, and the drain pipe 16 is controlled by operation control from the controller 26 when drain water is discharged. The side and the recirculation circuit 3 are switched to a state where they communicate with each other. Such switching means is not limited to the three-way switching valve 17, and may be configured by combining a plurality of electromagnetic on-off valves, for example. The target to which the downstream end of the outlet pipe 16 is connected via the switching means described above may be one or both of the return path 3a and the forward path 3b constituting the recirculation circuit 3, and this recirculation circuit One or both of the return path 3a and the forward path 3b that constitutes 3 constitutes a bath communication path that is connected to the bathtub 2 in communication. Further, as a target to which the downstream end of the outlet pipe 16 is connected, for example, a drain pipe piped on-site so that the bathtub pan 21 can be drained directly, or can be drained to a general drainage facility regardless of the bathtub 2. A drainage pipe that is piped like this may be used.

  A switching valve 8 is provided in the middle of the outlet pipe 13 for leading the drain water from the secondary heat exchanger 1 to the reforming tank 5, and the secondary heat exchanger is controlled by switching control of the switching valve 8. The flow path switching is performed such that the drain water derived from 1 flows down to the reforming tank 5 side, or the reforming tank 5 is bypassed through the bypass pipe 18 and directly flows into the neutralization tank 6. Yes. A bypass pipe 18 serving as a bypass flow path has an upstream end connected to the switching valve 8 and a downstream end joined to the outlet pipe 14.

  The flow path switching control of the switching valve 8 is performed by the controller 26 as a control means, so that rainwater or the like entering from the outlet 112 side of the secondary heat exchanger does not flow into the reforming tank 5. Yes. That is, the switching valve 8 is switched to the bypass pipe 18 during the non-combustion operation state in which the possibility of intrusion of rainwater or the like occurs, and there is no possibility of intrusion of rainwater or the like during the combustion operation state. Therefore, the switching valve 8 is switched to the reforming tank 5 side. At this time, since the generation of drain water in the secondary heat exchanger 1 is also performed in a predetermined time range immediately after the combustion operation is stopped, the switching valve is set for a predetermined set time even after the combustion operation is stopped. The flow path switching from the reformer tank 5 side to the bypass pipe 18 side is delayed so that the flow path is switched to the bypass pipe 18 when drain water is not substantially generated. I have to.

  In order to realize such channel switching, the controller 26 performs channel switching control of the switching valve 8 based on the current combustion operation information. That is, if the current operation state is the combustion operation state, the switching valve 8 is switched to the reformer tank 5 side, and if it is in the non-combustion operation state, the channel is switched to the bypass pipe 18 side. In addition, when the operation state changes from the combustion operation state to the non-combustion operation state, the switching valve 8 is moved from the reforming tank 5 side after waiting for the elapse of a preset delay setting time from the combustion operation stop time. The flow path is switched to the bypass pipe 18 side. On the contrary, when the operation state changes from the non-combustion operation state to the combustion operation state, the switching valve 8 may be immediately switched from the bypass pipe 18 side to the reforming tank 5 side.

  Whether the controller 26 is currently in the combustion operation state or the non-combustion operation state is determined based on whether or not the controller 26 itself is executing the combustion control of the combustion burners 31 and 36 (see FIG. 2) described later. , 36 for the combustion operation, the blower fan 311 (see FIG. 2) is operating, and the fuel gas control valve 312 (see FIG. 2) is opened for the combustion operation of the combustion burners 31, 36. What is necessary is to perform based on one or more combustion operation information whether it is actuated or whether flame detection means such as a frame rod detects the flame of the combustion burners 31 and 36. When performing the above determination based on the operating state of the blower fan 311, the blower operation is performed for scavenging for a predetermined time even after the combustion is stopped, so that the execution of the flow path switching is delayed even after the combustion is stopped. The delay setting time may be shortened by subtracting the scavenging time from the delay setting time. Furthermore, when performing the above determination based on the operating state of the blower fan 311, the scavenging time is set to be longer than the normal time by a time during which dripping of drain water in the secondary heat exchanger 1 will not occur. The switching valve 8 may be switched from the reforming tank 5 side to the bypass pipe 18 side after the air blowing fan 311 is blown for the scavenging time set longer than the normal time. That is, the long scavenging time is set as the delay setting time.

  A specific example of a latent heat recovery water heater to which the secondary heat exchanger 1, the reforming tank 5, the neutralizing tank 6 and the buffer tank 7 as shown in FIG. 1 are applied will be briefly described with reference to FIG.

  The latent heat recovery water heater illustrated in FIG. 2 is configured in a combined heat source machine type having both a hot water circulation heating function, a bath reheating function, and a bath hot water function in addition to the hot water function. High efficiency is achieved by recovering latent heat from combustion exhaust gas in addition to sensible heat in the combustion heating section. In practicing the present invention, the present invention can be applied to at least a combustion heating unit provided with a secondary heat exchanger 1 for recovering latent heat, and has a bath replenishment function. If the water circulation circuit 3 is installed, drain water using the bathtub 2 can be easily discharged, which is more preferable.

  In the figure, reference numeral 21 is a hot water supply circuit for realizing a hot water supply function, 22 is a heating circuit for realizing a hot water circulation heating function, and 23 is a reheating function for realizing a bath reheating function as a bath side circulation circuit. A circuit 24 is a pouring circuit for realizing a bath hot water filling function, and a reference numeral 25 performs each treatment of reforming and neutralizing drain water generated in the secondary heat exchanger 1 for recovering latent heat. A drain water treatment circuit 26 is a controller for controlling the operation of each circuit. In the hot water supply apparatus, the hot water of the heating circuit 22 is heated as a heat source, and the bath water of the hot water circuit 23 is heated by liquid-liquid heat exchange heating with the bath heater 41 to perform the hot water heating. Although it is a type, it is not limited to this, and a reheating is performed with a combustion heating section for reheating (a combustion burner and a heat exchanger heated by the combustion heat of this combustion burner). It may be configured.

  The hot water supply circuit 21 includes a combustion hot burner 31 for hot water supply and a primary heat exchanger 32 for hot water supply for heat exchange heating of the incoming water by the combustion heat of the combustion burner 31 as a combustion heating unit. Is heated mainly in the primary heat exchanger 32 for hot water supply, and the heated hot water is discharged into the hot water outlet 34. At this time, the water entering from the water inlet 33 is passed through the hot water supply heat exchanging portion 1a constituting the secondary heat exchanger 1 before entering the primary heat exchanger 32, In this heat exchanging portion 1a, the water is preheated by the latent heat recovery from the combustion exhaust gas, and then enters the primary heat exchanger 32 and is mainly heated. Then, the hot water heated to a predetermined temperature and discharged into the hot water supply passage 34 is supplied to predetermined hot water supply locations such as a hot water tap 35 and the pouring circuit 24 in a kitchen or bathroom. In the illustrated example, only one hot water tap 35 is shown, but there are usually a plurality of hot water taps 35 disposed in the kitchen, washbasin, bathroom, and the like. The primary heat exchanger 32 and a heating primary heat exchanger 37 described later constitute a sensible heat recovery heat exchanger, and are configured by the hot water supply heat exchanging portion 1a and a heating heat exchanging portion 1b described later. The secondary heat exchanger 1 constitutes a latent heat recovery heat exchanger.

  The heating circuit 22 includes a heating combustion burner 36 and a heating primary heat exchanger 37 that heats and heats the circulating hot water using the combustion heat of the combustion burner 36 as a combustion heating unit, and this heating primary heat exchanger A heating hot water circulation path 38 is passed through 37.

  The hot water circulation path 38 sends low temperature water returned to the expansion tank 39 and stored to the inlet of the heating primary heat exchanger 37 by the operation of the heating circulation pump 40, where it is heated by the combustion burner 36. Hot water is supplied as a heat source to the bath heater 41, which is a liquid-liquid heat exchanger, from the high temperature outgoing path 38a, or supplied to the high temperature heating terminal 43 such as a bathroom dryer via the high temperature outgoing header 42. It has become. Further, by the operation of the circulation pump 40, the low-temperature water in the expansion tank 39 is supplied to the low-temperature heating terminal 45 such as a floor heater via the low-temperature forward header 44, and heat is radiated from all the heating terminals 43 and 45. The low-temperature water having a low temperature is circulated such that the low-temperature water is returned to the expansion tank 39 after passing through the return header 46 through the heating heat exchanger 1b of the secondary heat exchanger 1 for latent heat recovery. ing. In the heating heat exchanging portion 1b of the secondary heat exchanger 1, the low-temperature water is returned to the expansion tank 39 in a preheated state by the latent heat recovery from the combustion exhaust gas of the heating combustion burner 36.

  In the reheating circuit 23, a bath heater 41 as a liquid-liquid heat exchange type heating unit is interposed in a recirculation circulation path 3 composed of a return path 3a and a forward path 3b. The bath water taken out from 2 through the return pipe 30a and the return path 3a is sent to the bath heater 41, where it is reheated by liquid-liquid heat exchange using high-temperature water on the heating circuit 22 side as a heat source. The heated bath water is sent to the bathtub 2 through the outgoing path 3b and the outgoing pipe 30b.

  The pouring circuit 24 includes a pouring passage 48 in which an upstream end branches from the hot water supply circuit 21 and a downstream end joins the recirculation circuit 3, and a pouring solenoid valve that switches between performing and shutting off pouring by opening / closing switching. 49. The pouring solenoid valve 49 is controlled to be opened and closed by the controller 26, and by pouring, the hot water in the hot water outlet channel 34 is poured into the bathtub 2 through the pouring channel 48 and the recirculation circuit 3 (return channel 3a). A predetermined amount of hot water filling is performed.

  The drain water treatment circuit 25 is a drain generated by the flue gas being cooled and condensed by heat exchange for latent heat recovery in the secondary heat exchanger 1 (hot water heat exchange section 1a and heating heat exchange section 1b). It is a circuit that is installed to add reforming treatment and sterilization / neutralization treatment, which is a formaldehyde removal treatment, to the water for discharge to the outside of the machine or to flow into the bathtub 2 for reuse. is there.

  That is, in the drain water treatment circuit 25, if the current state is in the combustion operation state, the switching valve 8 is disposed at the lower position of the secondary heat exchanger 1 with the flow path switched to the reforming tank 5 side. The drain water collected and collected by the drain pan 11a (see FIG. 1) is introduced into the reforming tank 5 through the outlet pipe 13, and formaldehyde is removed by a decomposition reaction using a manganese dioxide catalyst as a reforming material. Is given. Next, the drain water after the reforming treatment is led to the neutralization tank 6 through the outlet pipe 14 and is neutralized by bringing it into contact with the neutralizing agent filled in the sterilization treatment and the neutralization tank 6. . Next, the drain water subjected to the neutralization treatment is guided to the buffer tank 7 through the outlet pipe 15 and is temporarily stored until a predetermined discharge timing comes. When the discharge timing arrives, the three-way switching valve 17 is switched by the operation control of the controller 26, whereby the drain water in the buffer tank 7 passes through the lead-out pipe 16 and recirculates the circulation path 3 (in FIG. 2, the forward path 3b). It is made to flow into the bathtub 2 by being flown into the example). On the other hand, if the current state is the non-combustion operation state, the switching valve 8 is switched to the bypass pipe 18 side, and even if rainwater or the like enters, the intruding water is led out from the outlet pipe 13. Subsequently, it is introduced into the neutralization tank 6 through the bypass pipe 18, and the sterilization process and the neutralization process in the neutralization tank 6 are performed without undergoing the reforming process in the reforming tank 5. Thereafter, it is guided to the buffer tank 7 and temporarily stored in the same manner as described above.

  As said discharge | emission timing, what is necessary is just to set the timing when the bathtub 2 is not used, ie, the timing when the hot water filling for bathing is not performed. Assuming the amount of drain water generated in one day depending on the scale and usage environment of the hot water supply capacity of the latent heat recovery water heater E, the discharge timing and the amount per day are calculated in consideration of the amount of drain water and the amount stored in the buffer tank 7. The number of times may be set. For example, assuming that the assumed maximum drain water amount generated per day is 10 L and the storage amount of the buffer tank 7 is set to 4 L, the discharge timing may be set three times a day. As the discharge timing, it is only necessary to select and set a timing at which the automatic washing of the bathtub or the control related to automatic hot water filling or automatic heat insulation is not performed. As setting of the discharge timing according to the time, a time zone in which bathing is not normally performed such as 10 am, 4 pm or 2 am may be selected.

  In the example of FIG. 2, the reforming tank 5 is disposed close to the burner case (combustion can body) of the combustion burners 31 and 36 so that the heat of combustion heat of the combustion burners 31 and 36 can be received from the burner case. It has become. For example, it may be disposed in contact with the side surface of the burner case, or may be disposed with a slight gap from the side surface of the burner case without contact. As a result, the drain water in the reforming tank 5 is heated by heat transfer from the combustion heat and maintained at a predetermined high temperature state, and the formaldehyde removal reaction by the manganese dioxide catalyst is promoted to increase the treatment speed. Become. That is, the drain water derived from the secondary heat exchanger 1 and reformed in the reforming tank 5 can be brought to a higher temperature state than that as it is derived from the secondary heat exchanger 1, and as a result Compared to the case where the drain water as derived from the secondary heat exchanger 1 is used as the water to be treated and reformed in the reforming tank 5, the oxidation reaction for removing formaldehyde can be further promoted, and the reaction rate is increased. It is possible to increase the processing speed and the processing time. In addition, by utilizing the heat transfer according to such an arrangement, heat for promoting the formaldehyde removal reaction from the drain water can be obtained without requiring other heat source power. For example, the temperature of the drain water immediately after being derived from the secondary heat exchanger 1 which is about 40 ° C. in the hot water supply heat exchanging portion 1 a and about 57 ° C. in the heating heat exchanging portion 1 b receives heat transfer from the burner case. The temperature can be raised to about 70 ° C.

  In the case of the above first embodiment, since the switching valve 8 is switched to the reforming tank 5 during the combustion operation state, there is no intrusion / mixing of rainwater or the like from the secondary heat exchanger 1. The drain water can be introduced into the reforming tank 5 and subjected to the reforming treatment, then sterilized and neutralized in the neutralizing tank 6, and then drained after temporary storage in the buffer tank 7. On the other hand, since the switching valve 8 is switched to the bypass pipe 18 during the non-combustion operation state in which no drain water is generated, rainwater or the like is discharged from the outlet 112 (see FIG. 1) of the secondary heat exchanger 1. Even if intrusion occurs, it is not introduced into the reforming tank 5 but can be directly introduced into the neutralization tank 6 by bypassing the reforming tank 5 by the bypass pipe 18. As a result, the reforming tank 5 can be set to a minimum volume corresponding to the maximum required treatment amount of drain water without considering intrusion / mixing of rainwater, etc., and the entire latent heat recovery water heater can be made compact. It does not inhibit. Furthermore, it is possible to avoid the inconvenience that the reforming material in the reforming tank 5 is poisoned or consumed by components dissolved in rainwater, etc., and the life of the reforming material can be extended. it can. In addition, when rainwater or the like is introduced into the neutralization tank 6 through the bypass pipe 18, the sterilization treatment by the sterilization means 61 is performed on the rainwater or the like, so that microorganisms contained in the rainwater or the like can be sterilized. The propagation and proliferation of microorganisms can be avoided during the temporary storage period in the buffer tank 7. Thereby, even if it uses the bathtub 2 as a discharge destination, generation | occurrence | production of the disadvantage with respect to the bathtub 2 can be avoided.

  As shown by reference numeral 18a in FIG. 1, the downstream end of the bypass pipe 18a is joined to the outlet pipe 15 so that the rainwater or the like whose flow path is switched by the switching valve 8 is directly guided to the buffer tank 7. May be. That is, the intruding water derived from the secondary heat exchanger 1 is guided to the buffer tank 7 by bypassing the drain water treatment unit composed of the reforming tank 5 and the neutralizing tank 6. By doing in this way, it is avoided that the neutralizing agent in the neutralizing tank 6 is consumed due to rain water or the like, and also the wear of the neutralizing agent due to acid rain is avoided, for example. It is possible to extend the life of the battery. In this case, the buffer tank 7 may be drained directly to the bathtub pan 21 or the general drainage facility.

Second Embodiment
FIG. 3 shows a main part of a latent heat recovery water heater according to the second embodiment of the present invention. In the second embodiment, a small-capacity buffer tank 9 as a tank and a water detection means 92 in the small-capacity buffer tank 9 are added to the first embodiment, so that determination accuracy or detection accuracy of intrusion of rainwater and the like is added. Is higher than that of the first embodiment. In addition, since the other component of the said 2nd Embodiment is the structure similar to the thing of 1st Embodiment, the same code | symbol is attached | subjected to the same component and the detailed description is abbreviate | omitted.

  The small-capacity buffer tank 9 is interposed in a lead-out pipe connecting the secondary heat exchanger 1 and the switching valve 8, and the inlet side is communicated with the inside of the secondary heat exchanger 1 through the lead-out pipe 13a. The switching valve 8 is connected through the outlet pipe 13b with the on-off valve 91 interposed on the outlet side. Further, a water detection means 92 is provided in the small-capacity buffer tank 9 to detect whether water is present (presence or absence of water) and to output it to the controller 26. For example, a water level electrode may be used as the water detection means.

  The flow path switching control of the switching valve 8 by the controller 26 in the second embodiment is performed as follows. That is, if it is determined that the current operation state is the combustion operation state based on the combustion operation information similar to that described in the first embodiment, the on-off valve 91 is opened and the switching valve 8 is set in the reforming tank 5. The channel is switched to the side. Thereby, the drain water generated in the secondary heat exchanger 1 during the combustion operation is transferred to the reforming tank 5 through the outlet pipe 13a, the small-capacity buffer tank 9, the open / close valve 91, the outlet pipe 13b, and the switching valve 8. be introduced. As described in the first embodiment, the buffer tank 7 is temporarily stored after the reforming process in the reforming tank 5 and the sterilization / neutralization process in the neutralizing tank 6, and the arrival of a predetermined discharge timing. For example, it is discharged to the bathtub 2 or the like.

  On the other hand, if it is determined on the basis of the combustion operation information that the current operation state is the non-combustion operation state, the on-off valve 91 is closed and thereafter the presence or absence of the output of the water detection signal from the water detection means 92 is monitored. To do. If there is no output of the water detection signal, that is, there is no flow of water from the secondary heat exchanger 1 to the small capacity buffer tank 9 regardless of drain water or rain water, the flow of the switching valve 8 until then The above-mentioned monitoring is continued while maintaining the path switching state. If there is an output of a water detection signal from the water detection means 92, it is determined that rainwater or the like has entered due to the flow of water despite the non-combustion operation state. Since there is a possibility that the flow of drain water remaining in the secondary heat exchanger 1 may also be included, the water detection signal from the water detection means 92 is output for the first time when water accumulates to a predetermined water level. That's fine. If it is determined that rainwater or the like has entered, the switching valve 8 is switched from the reforming tank 5 side to the bypass pipe 18 side, and the on-off valve 91 is opened. As a result, even if rainwater or the like enters, the rainwater or the like is directly introduced into the neutralization tank 6 through the bypass pipe 18 without passing through the reforming tank 5. Alternatively, it is introduced directly into the buffer tank 7 through the bypass pipe 18a without passing through the reforming tank 5 and the neutralization tank 6.

  As described above, in the case of the second embodiment as well, it is possible to obtain the same effects as the effects according to the first embodiment, and in the non-combustion operation state by the small-capacity buffer tank 9 and the water detection means 92. Nevertheless, by detecting the presence of water, it is possible to grasp and detect the occurrence of intrusion of rainwater and the like more accurately, and to more reliably perform flow path switching control of the switching valve 8 for bypassing rainwater and the like. become able to.

  In addition to the water detection means 92, a pH sensor is installed for the small-capacity buffer tank 9, and the water detected by the water detection means 92 based on the pH value detected by the pH sensor is drain water or rain water. The flow path switching control of the switching valve 8 may be performed after determining whether or not. By doing in this way, it becomes possible to more reliably perform the bypass of the intruding water.

<Other embodiments>
The present invention is not limited to the first and second embodiments described above, but includes other various embodiments. That is, in each of the above embodiments, the neutralization process in the neutralization tank 6 is performed after the reforming process in the reforming tank 5, but the neutralization process in the neutralization tank is performed first. You may make it perform the modification process in a modification tank. That is, you may make it arrange | position a modification tank in the downstream position of a neutralization tank with respect to the flow of drain water. In this case, both the neutralization tank and the reforming tank may be bypassed from the switching valve 8 as in the bypass pipe 18a.

  Further, when the sterilization means 61 of the neutralization tank 6 is separated and made independent as a sterilization apparatus, that is, the drain water treatment unit is constituted by the neutralization tank and / or the reforming tank except for the sterilization apparatus, and the drain water treatment to be bypassed When the sterilizer is excluded from the section, the sterilizer is disposed downstream from the position where the downstream end of the bypass pipe (bypass channel) joins the drain water collection and drainage channel. What is necessary is just to make it drain or temporarily store after passing through the sterilizer and sterilizing microorganisms. For example, when the drainage water collection and drainage channel is inserted in series in the order of the reforming tank-neutralization tank-sterilizer, the reforming tank and the neutralization tank are branched from the upstream position of the reforming tank. What is necessary is just to join the bypass pipe (bypass flow path) made to bypass between a neutralization tank and a sterilizer. Similarly, in the case where the neutralization tank, the reforming tank, and the sterilizer are interposed in series with respect to the drain water collection and drainage channel, the neutralization tank and the reforming tank are branched from the upstream position of the neutralization tank. What is necessary is just to join the bypass pipe (bypass flow path) which made it bypass by between a reformer and a sterilizer. In the above case, the configuration can be configured with only one bypass pipe (bypass flow path), but in the following case, the configuration may be provided with two bypass pipes (bypass flow paths). That is, when interposing in the order of the reforming tank-sterilization tank-neutralization tank, or when interposing in the order of neutralization tank-sterilization tank-reforming tank, The intruding water that is bypassed by the bypass pipe (bypass flow path) by bypassing the reforming tank and the neutralization tank is sure to pass through the sterilizer.

  In each of the above embodiments, when the drain water treatment unit is constituted by the reforming tank 5, it is bypassed by the bypass pipe 18, and when the drain water treatment unit is constituted by both the reforming tank 5 and the neutralization tank 6. Is bypassed by the bypass pipe 18a, but in addition to these, the drain water treatment part is provided only by one of the reforming tank 5 or the neutralization tank (neutralization tank 6 excluding the sterilization means 61 from the neutralization tank 6). Only the drain water treatment section composed of only one of the above may be interposed between the secondary heat exchanger 1 and the buffer tank 7, and in this case, the reformer tank 5 or the inside What is necessary is just to make it bypass the drain water treatment part comprised only by one side of the sump tank 6. FIG. Even in these cases, it is possible to avoid the consumption due to the intruding water in the reforming material of the reforming tank 5 or the neutralizing agent of the neutralizing tank, and it is possible to extend the service life thereof. In this case, the intrusion water that bypasses the drain water treatment unit may be guided to a sterilization means (sterilization device) and sterilized to be drained.

  The drain pan 11a in each of the above embodiments is formed so as to have a downwardly inclined surface toward the upstream opening end 131 of the outlet pipe 13. However, the present invention is not limited to this. You may form so that it may become. This is because the drain plane can be led out from the upstream opening end 131 if the drain water is collected even if it is a horizontal plane.

  In each said embodiment, although the drain pan 11a is comprised by the bottom face of the baseplate 113, and the bottom face of the baseplate 113 is made into the inclined surface, not only this but a drain pan in the case of the secondary heat exchanger 1 separately from a baseplate. In the case of arrangement, it is not necessary to incline the bottom plate, and the upper surface of the drain pan arranged on the bottom surface side of the bottom plate may be constituted by an inclined surface.

It is a mimetic diagram showing the important section of the latent heat recovery hot water supply machine of a 1st embodiment of the present invention. It is a schematic diagram which shows the example of what actualized the latent-heat recovery water heater of FIG. It is a FIG. 1 corresponding view which shows the principal part of the latent heat recovery water heater of 2nd Embodiment of this invention.

Explanation of symbols

1 Secondary heat exchanger (heat exchanger for latent heat recovery)
5 Reforming tank (reforming equipment)
6 Neutralization tank (neutralization equipment)
8 Switching valve (channel switching means)
9 Small-capacity buffer tank (tank)
13, 13a, 13b, 14, 15, 16 Lead pipe (drain water collection drainage channel)
18, 18a Bypass pipe (bypass flow path)
26 controller (control means)
61 Sterilization means (sterilization equipment)

Claims (5)

A sensible heat recovery heat exchanger that recovers sensible heat from the combustion gas generated by combustion of the burner, and a latent heat recovery heat exchanger that recovers latent heat from the combustion exhaust gas after passing through the sensible heat recovery heat exchanger, , A latent heat recovery water heater provided with a drain water collection and drainage channel for collecting and draining drain water generated in the latent heat recovery heat exchanger,
A drain water treatment unit interposed in the middle of the drain water collection drainage channel, and a downstream position bypassing the drain water treatment unit branching from the drain water collection drainage channel located upstream from the drain water treatment unit A bypass flow path that merges with the drain water collection and drainage channel, and a drain water collection and drainage channel at the position where the bypass flow branches, and the flow path is either the drain water treatment unit side or the bypass flow channel side And a control means for controlling the switching of the channel switching means to the bypass channel side so that intruded water that has entered the latent heat recovery heat exchanger from the outside is not supplied to the drain water treatment section. And
A latent heat recovery water heater characterized by that. The latent heat recovery water heater according to claim 1,
When the burner is in a non-combustion operation state and drain water is not substantially generated in the latent heat recovery heat exchanger, the control means controls the flow path switching means to the bypass flow path side. A latent heat recovery water heater configured to do. A sensible heat recovery heat exchanger that recovers sensible heat from the combustion gas generated by combustion of the burner, and a latent heat recovery heat exchanger that recovers latent heat from the combustion exhaust gas after passing through the sensible heat recovery heat exchanger, , A latent heat recovery water heater provided with a drain water collection and drainage channel for collecting and draining drain water generated in the latent heat recovery heat exchanger,
A drain water treatment unit interposed in the middle of the drain water collection drainage channel, and a downstream position bypassing the drain water treatment unit branching from the drain water collection drainage channel located upstream from the drain water treatment unit A bypass flow path that merges with the drain water collection and drainage channel, and a drain water collection and drainage channel at the position where the bypass flow branches, and the flow path is either the drain water treatment unit side or the bypass flow channel side A flow path switching means for switching to the tank, a tank interposed in a drain water collection / drainage channel upstream of the flow path switching means, a water detection means for detecting the presence of water in the tank, and the flow Control means for controlling flow path switching by the path switching means,
The control means is configured to execute flow path switching control based on the output of a water detection signal from the water detection means and the combustion operation state of the burner.
A latent heat recovery water heater characterized by that. The latent heat recovery water heater according to any one of claims 1 to 3,
The drain water treatment unit is constituted by one or both of a reformer that removes a harmful substance contained in the drain water and reforms, and a neutralizer that neutralizes the drain water. Latent heat recovery water heater. The latent heat recovery water heater according to any one of claims 1 to 4,
A sterilizer for sterilizing drain water is interposed in the drain water collection drainage channel, and the downstream end of the bypass channel is connected to join the drain water collection drainage channel located upstream of the sterilization device. There is a latent heat recovery water heater.

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