JP2010007980A - Latent heat recovery heat source machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a latent heat recovery heat source machine, draining water after the drainage is simply and surely cleaned. <P>SOLUTION: The drainage generated with latent heat recovery from combustion exhaust gas by a secondary heat exchanger 6 is neutralized in a neutralizing vessel 51, and the neutralized drainage is filtered in a filtering vessel 52. A reverse osmosis film is taken as a filtration film, and the boundary between a raw solution passage for running a filtering object and a filtration passage which filtered clean water enters is partitioned by the filtration film, and the pressurized water to be treated is caused to flow into the raw solution passage by a drain pump 53 according to a crossflow filtration system to be filtered. The filtered clean water is discharged from a delivery pipe 84, and unfiltered concentrated water is returned to the downstream part of the neutralizing vessel by a return pipe 83. In here, the neutralized drainage and the concentrated water are mixed to be circulated as the water to be treated and supplied to the filtering vessel. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a latent heat recovery heat source unit that recovers latent heat of combustion exhaust gas by heat exchange with combustion exhaust gas in a heat exchanger for recovering latent heat, and in particular, purifies drain water generated during the recovery of latent heat. It relates to a latent heat recovery heat source machine that can be easily drained.

  Generally, a latent heat recovery heat source machine is a secondary heat for recovering latent heat recovery after recovering sensible heat of combustion gas with a primary heat exchanger to heat the object to be heated and then passing the combustion exhaust gas after passing through the primary heat exchanger. It is a heat source machine that is introduced into the exchanger to further recover the latent heat of the combustion exhaust gas, thereby improving efficiency. In such a latent heat recovery heat source machine, when the latent heat recovery is performed in the secondary heat exchanger, the flue gas in contact with the secondary heat exchanger causes the water vapor in the flue gas to condense and condense, and drain water (condensation water). ) Will occur. Since this drain water contains nitrogen oxides (NOx) and sulfur oxides (SOx) taken from combustion exhaust gas and is strongly acidic, it is necessary to at least neutralize it to drain it to the outside. Usually, in order to collect drain water and perform neutralization treatment, a neutralization tank is built in and installed in a heat source machine.

  Conventionally, in order to treat drain water generated during the recovery of latent heat, strong acidic drain water is passed between an anode and a cathode that are energized with direct current to remove harmful substances such as lead and copper. It is known that water quality is improved to a hydrogen ion concentration of pH 5.8 or higher, and then suspended precipitates such as lead hydroxide and copper hydroxide are filtered with a filter paper and then drained. (For example, refer to Patent Document 1).

  In addition, for drain water collected by steam piping that feeds steam generated in the boiler, the drainage water that has passed through the filter after removing solids such as iron fine particles on the piping scale with a filter is used for boilers. There is also known one that is reused as supplementary water (for example, see Patent Document 2).

Japanese Examined Patent Publication No. 62-42222 JP 2001-50499 A

  By the way, in order to drain the drain water generated due to the recovery of latent heat from the combustion exhaust gas as a general waste water, it is not sufficient to simply perform the neutralization treatment, and it is considered that the drain water is dissolved or mixed in the drain water. It is thought that it is necessary to remove and purify unnecessary impurities.

  However, impurities that are considered to be dissolved or mixed in the drain water are not solids that can be removed by simply filtering, but are propagated in formaldehyde, in the process of neutralization, or mixed in by rainwater blowing. Because it is a miscellaneous bacteria, it is necessary to purify it with appropriate chemical treatment and sterilization treatment, and it will be a large measure as a countermeasure to be added to the drain heat purification treatment for the latent heat recovery heat source machine. .

  This invention is made | formed in view of such a situation, The place made into the objective is providing the latent-heat-recovery heat-source machine which can be made to drain after performing the purification process of drain water simply and reliably. It is in.

  In order to achieve the above object, in the present invention, a primary heat exchanger that recovers sensible heat from combustion gas generated by combustion of a burner and a latent heat that recovers latent heat from combustion exhaust gas after passing through the primary heat exchanger are provided. The following specific matters were provided for a latent heat recovery heat source device including a secondary heat exchanger and a drain water treatment circuit for treating drain water generated in the secondary heat exchanger. That is, as the drain water treatment circuit, a neutralization tank for neutralizing the drain water, a filtration tank for filtering the neutralized drain water after being neutralized by the neutralization tank as treated water, It is assumed that a drain pump that discharges the water to be treated to the filtration tank and a return path that returns the untreated water to be filtered from the filtration tank to the downstream portion of the neutralization tank. The filtration tank includes a filtration membrane, and the purified water filtered through the filtration membrane is discharged to the downstream side, while the unfiltered water that does not pass through the filtration membrane passes through the return path. (Claim 1).

  In the case of this invention, it becomes possible to remove the impurities dissolved in the neutralized drain water by the filtration membrane of the filtration tank and filter it into purified water. Therefore, purified water rendered harmless by filtration Can be easily drained into a general drainage facility as it is. On the other hand, unfiltered water that does not pass through the filtration membrane is returned by the return path, mixed with the neutralized drain water, circulated through the filtration tank, and the filtration process can be continuously repeated. It becomes possible. Further, by realizing the filtration process in such a continuous flow state, the filtration process can be repeatedly performed continuously without applying an extra load to the filtration membrane, and the unfiltered coating can be performed. There is no need to take any special measures such as draining or storing the treated water outside the machine.

  As the filtration tank in the present invention, a raw liquid flow path through which treated water flows toward the return path, a filtration flow path through which filtered purified water flows downstream, the filtration flow path and the raw liquid flow path (Claim 2), and in this way, it is ensured that the filtration process is continued while flowing the water to be treated. It becomes possible, and it becomes possible to repeat a filtration process, without applying an excessive load with respect to the filtration membrane in said filtration tank. In addition, the filtration tank may be provided with a filtration membrane, and the water to be treated may be caused to flow along the surface of the filtration membrane by a cross flow filtration method (Claim 3). Thus, the filtration process performed while flowing the water to be treated can be realized more reliably. In addition, when the filtration process is performed by the total filtration method, the life is shortened due to the load on the filtration membrane, whereas the use of the cross flow filtration method makes it possible to extend the life of the filtration membrane longer. Become. On the other hand, in the case of the cross flow filtration method, drainage of unfiltered treated water is usually required along with filtered water. However, in the present invention, the unfiltered treated water is returned as described above. Therefore, it is not necessary to take measures for draining unfiltered water to be treated.

  Further, in the present invention, further functions can be obtained by adding various components as described below. That is, first, a buffer tank is interposed downstream of the neutralization tank and upstream of the filtration tank, and the return path is returned to the buffer tank so that the unfiltered water is returned to the buffer tank. It is possible to connect the downstream ends of the two (claim 4). By doing so, as treated water circulated from the buffer tank to the filtration tank for the filtration treatment, neutralized drain water flowing down from the neutralization tank to the buffer tank and unreturned water returned from the return path. Thus, the water to be treated for filtration can be surely mixed.

  Secondly, the conveyance flow rate adjusting means that changes and adjusts the conveyance flow rate of the water to be treated with respect to the filtration tank, and the conveyance flow rate of the treatment water corresponds to the amount of drain water generated by controlling the operation of the conveyance flow rate adjustment means. And a control means for changing it (claim 5). By doing so, it becomes possible to balance the amount of drain water generated in the secondary heat exchanger and subject to drain water treatment to the conveyance flow rate of water to be treated subject to filtration. Therefore, it is possible to perform drain water treatment in a state without excess or deficiency.

  Thirdly, a bypass path that bypasses the filtration tank and switching means that can switch the discharge side of the drain pump to either the filtration tank side or the bypass path side are provided, and the switching means is switched to the bypass path side. Thus, the water to be treated can be discharged to the downstream side without passing through the filtration tank (claim 6). By doing so, the switching means is switched at a drain timing that does not cause any inconvenience due to drainage of the treated water that has been returned through the return path without being filtered and has been enriched with impurities by continuing filtration. Thus, the drain water treatment circuit can be discharged through the bypass passage, and the subsequent filtration treatment can be continued without applying an excessive load to the filtration membrane. As a result, it is possible to improve the durability by avoiding shortening the life of the filtration membrane.

  Fourthly, a check valve for preventing inflow in the reverse flow direction to the filtration tank side can be interposed in the outlet path for discharging the purified water from the filtration tank to the downstream side (Claim 7). By doing so, even if the downstream end of the outlet path for draining the purified water is connected to any facility, the back flow of hot water from the facility side is prevented and the purified water remains as purified water. It becomes possible to make it.

  A reverse osmosis membrane can be used as the filtration membrane provided in the filtration tank of the latent heat recovery heat source machine. By doing so, it becomes possible to remove all impurities and bacteria such as formaldehyde dissolved in the water to be treated, and the purified water after filtration can be rendered harmless.

  As described above, according to any one of claims 1 to 8, the latent heat recovery heat source machine removes and purifies impurities dissolved in the neutralized drain water by the filter membrane of the filter tank. The water can be filtered, and the purified water that has been rendered harmless by filtration can be drained easily and directly into a general drainage facility. On the other hand, unfiltered water that does not pass through the filtration membrane can be returned as it is through the return path, mixed with the neutralized drain water and circulated through the filtration tank, and the filtration process can be continued repeatedly. become able to. In addition, filtration in such a continuous flow state can be realized, and without applying an extra load on the filtration membrane, untreated water to be treated is drained or stored outside the machine. It is possible to eliminate the need to take special measures such as

  According to the second aspect of the present invention, it is possible to reliably realize the filtration process while flowing the water to be treated by partitioning the stock solution flow path and the filtration flow path along the flow paths by the filtration membrane. Thus, the filtration process can be repeated without reliably applying an extra load to the filtration membrane. In addition, according to claim 3, by allowing the water to be treated to flow along the surface of the filtration membrane by the cross-flow filtration method, it is possible to more surely realize the filtration treatment while performing the water to be treated. Will be able to. In addition, while it is possible to reliably increase the life of the filtration membrane, it is not necessary to take measures for draining unfiltered water even if a cross-flow filtration method is employed.

  According to claim 4, by providing a buffer tank, neutralization that flows down from the neutralization tank to the buffer tank as water to be circulated from the buffer tank to the filtration tank for the filtration treatment. The treated drain water and the unfiltered water to be treated returned from the return path can be reliably mixed.

  According to the fifth aspect of the present invention, by providing a transport flow rate adjusting means capable of changing and adjusting the transport flow rate of the water to be treated with respect to the filtration tank, and a control means, the drain water treatment is generated in the secondary heat exchanger. It is possible to balance the amount of drain water generated that is subject to the filtration and the conveyance flow rate of the water to be treated that is subject to filtration, and it is possible to realize drain water treatment in a state where there is no excess or deficiency. .

  According to claim 6, by providing a bypass passage for bypassing the filtration tank and a switching means for switching the discharge side of the drain pump to the bypass passage side, impurities are concentrated without being filtered by continuing the filtration treatment. The treated water can be discharged from the drain water treatment circuit through the bypass passage, and the subsequent filtration treatment can be continued without imposing an excessive load on the filtration membrane. The durability can be improved by avoiding shortening of the life of the film.

  According to claim 7, even if the downstream end of the outlet path for draining the purified water is connected to any facility by interposing a check valve in the outlet path for discharging the purified water downstream from the filtration tank. The back flow of hot water from the facility side can be prevented, and the purified water can be maintained as the purified water.

  According to claim 8, by using the reverse osmosis membrane as the filtration membrane, all impurities and bacteria such as formaldehyde dissolved in the water to be treated can be removed, and the purified water after filtration is truly treated. Can be rendered harmless.

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

<First Embodiment>
FIG. 1 shows a latent heat recovery heat source apparatus according to the first embodiment of the present invention. This latent heat recovery heat source machine is configured in a composite heat source machine type having both a bath replenishment function and a bath hot water filling function in addition to a hot water supply function. In addition to the above, the latent heat is also recovered from the combustion exhaust gas, so that it is configured as a latent heat recovery type that achieves high efficiency. In practicing the present invention, any apparatus having at least a secondary heat exchanger 6 for recovering latent heat from combustion exhaust gas can be applied, and has a bath replenishment function. If the water circulation circuit 32 is installed, it is more preferable because drain water can be easily discharged using the recirculation circuit or a drainage facility of a bathtub (not shown).

  In the figure, reference numeral 2 is a hot water supply circuit for realizing a hot water supply function, 3 is a reheating circuit for realizing a bath reheating function, 4 is a pouring circuit for realizing a hot water filling function, Reference numeral 5 denotes a drain water treatment circuit for neutralizing and purifying drain water generated in the secondary heat exchanger 6 for recovering latent heat, and 7 is a controller for controlling the operation of each circuit.

  The hot water supply circuit 2 includes a burner 8 and a primary heat exchanger 21 for hot water supply for heat exchange heating of the incoming water by sensible heat (combustion heat) of the combustion gas of the burner 8. In the hot water supply primary heat exchanger 21, the hot water is mainly heated, and the heated hot water is discharged into the hot water outlet 23. At this time, the water from the water inlet 22 is passed through the secondary heat exchanger 6 disposed in the exhaust collecting cylinder before entering the primary heat exchanger 21. The secondary heat exchanger 6 is preheated by recovering latent heat from the combustion exhaust gas, and enters the primary heat exchanger 21 through the water inlet connection path 24 to be mainly heated. Then, the hot water heated to a predetermined temperature and discharged to the hot water supply passage 23 is supplied to a predetermined hot water supply location such as a hot water tap 25 such as a kitchen or a bathroom or the pouring circuit 4. In the illustrated example, only one hot water tap 25 is shown, but there are usually a plurality of hot water taps 25 disposed in the kitchen, washstand, bathroom, and the like. The primary heat exchanger 21 and a reheating primary heat exchanger 31 that uses fins in common with the primary heat exchanger 21 constitute a sensible heat recovery heat exchanger, and the secondary heat exchanger 6 has latent heat recovery heat. Configure the exchanger. In addition, an incoming water flow sensor 26, an incoming water temperature sensor 27, and the like are interposed in the incoming water passage 22, and a flow control valve 28, a hot water supply temperature sensor 29, and the like are interposed in the hot water outlet 23.

  The reheating circuit 3 recirculates bathtub water between a reheating primary heat exchanger 31 that heats and heats the circulating hot water by sensible heat of the combustion gas of the burner 8 and a bathtub (not shown). And a recirculation circuit 32 to be driven. In the reheating circulation path 32, the bath water from the bathtub is returned to the primary heat exchanger 31 through the return path 32 a by the operation of the recirculation circulation pump 33, and is reheated and heated in the primary heat exchanger 31. The bathtub water after the bath is sent to the bathtub through the outgoing path 32b. The burner 8 is configured to operate by receiving fuel gas supplied from a fuel supply system having an original gas valve 81 and a gas proportional valve 82 interposed therebetween. The combustion capacity can be switched to a plurality of stages by opening / closing switching control of 83,.

  The pouring circuit 4 switches between the hot water supply path 41 where the upstream end branches from the hot water supply path 23 of the hot water supply circuit 2 and the downstream end is joined to the recirculation circuit 32 and the execution and shut-off of the pouring by opening / closing switching. A pouring solenoid valve 42 is provided. The pouring solenoid valve 42 is controlled to be opened and closed by the controller 7, and when pouring is performed, the hot water in the tapping path 23 is poured into the bathtub via the pouring path 41 and the recirculation circulation path 32 (return path 32a), and reaches a predetermined amount. The hot water filling is performed.

  The drain water treatment circuit 5 adds neutralization treatment and purification treatment to drain water generated by the combustion exhaust gas being cooled and condensed by heat exchange for latent heat recovery in the secondary heat exchanger 6. It is a circuit installed to discharge outside the machine. That is, the drain water treatment circuit 5 includes a neutralization tank 51, a filtration tank 52, a drain pump 53, and a check valve 54.

  The neutralization tank 51 is filled with a neutralizing agent (for example, calcium carbonate; not shown in FIG. 1). Drain water collected and collected by the drain pan 61 disposed at the lower position of the secondary heat exchanger 6 is introduced into the neutralization tank 51 from the inlet 511 of the neutralization tank 51 through the outlet pipe 81, While the drain water that has flowed in flows to the outlet 512 at the downstream end, the drain water is neutralized by contact with the neutralizing agent, and the drain water that has been neutralized (hereinafter referred to as “neutralized drain water”) is the outlet pipe 82. It is supplied to the filtration tank 52 through. During this supply, unfiltered water is merged as described later, and water to be treated, which is a mixed water of unfiltered water and neutralized drain water, is supplied to the filtration tank 52 in a pressurized state by the drain pump 53. It has become so.

  As shown in FIG. 2, the filtration tank 52 is composed of a raw liquid flow path 521 communicated with the downstream end of the outlet pipe 82 from the neutralization tank 51 and a filtration flow disposed adjacent to the raw liquid flow path 521. A passage 522 and a filtration membrane 523 constituting a boundary wall that partitions the filtration passage 522 and the stock solution passage 521 from each other are provided. That is, the stock solution channel 521 constitutes the primary side and the filtration channel 522 constitutes the secondary side across the filtration membrane 523, and the water filtered by the filtration membrane 523 passes from the primary side to the secondary side. Become. The downstream end of the stock solution flow path 521 is connected to a return pipe 83 as a return path, and the downstream end of the return pipe 83 is connected to a downstream portion on the outlet 512 side of the neutralization tank 51. The downstream end of the filtration channel 522 is connected to a lead-out pipe 84 as a lead-out path, and the downstream end of the lead-out pipe 84 is connected to the drain side. In the example of FIG. 1, the downstream end of the outlet pipe 84 is connected to the recirculation circuit 32 (return path 32 a), and is communicated to the drainage port of the bathtub facility via this recirculation circuit 32. Yes. The check valve 54 is interposed in the outlet pipe 84 on the upstream side of the junction with the recirculation circuit 32, and the bath water on the recirculation circuit 32 side flows into the drain water treatment circuit 5 side. I try to prevent you from doing it.

  When the filtration membrane 523 is further described, the filtration membrane 523 is formed by a reverse osmosis membrane (RO membrane; Reverse Osmosis Membrane). This reverse osmosis membrane is a filtration membrane having a pore size of approximately 2 nm (nanometers) or less and allowing water to permeate, but impervious to impurities such as ions and salts, bacteria and viruses. The filtration membrane 523 is preferably formed of a reverse osmosis membrane, but instead, it is formed using an ultrafiltration membrane (UF membrane; Ultra-filtration Membrane) having a pore size of, for example, 10 nm or less. However, it is possible to remove the impurities, bacteria, viruses and the like in the same manner. Then, the water to be treated is caused to flow along the surface of the filtration membrane 523 while being pressurized by the discharge pressure of the drain pump 53, and in the process of flowing, the water passes through the side filtration membrane 523 and enters the filtration channel 522. The purified (detoxified) filtered water flows through the outlet pipe 84 to the drain side. That is, it is filtered by flowing by the cross flow filtration method. On the other hand, the concentrated water in which impurities and the like are concentrated in the undiluted solution flow path 521 without being filtered is returned to the downstream side portion of the neutralization tank 51 through the return pipe 83, and the neutralized drain water inside the downstream portion at this downstream side portion. And concentrated water will be mixed. By this mixing, the concentrated water is diluted, and the neutralized drain water in the downstream portion of the neutralization tank 51 is pushed out and supplied to the filtration tank 52. And the to-be-processed water after dilution flows again through the outlet pipe 82 and the drain pump 53 into the raw solution flow path 521 of the filtration tank 52, and the above-mentioned filtration and flow of the filtered water to the drain side and unfiltered concentrated water. The return circulation is repeated.

  In addition, as said filtration membrane 523, the thing of various structures, such as a hollow fiber membrane, a spiral membrane (spiral membrane), or a tubular membrane (cylindrical membrane), can be employ | adopted, and it is as a filtration direction. Either from the outside to the inside or from the inside to the outside can be employed. Further, as the structure in the filtration tank 52 of the stock solution channel 521 and the filtration channel 522 sandwiching such a filtration membrane 523, for example, a spiral membrane is used in addition to the basic arrangement and structure shown in FIG. It is also possible to adopt an arrangement / structure in which the flow direction of the flow path extends spirally.

  For example, an AC pump may be used as the drain pump 53 as long as a predetermined pressure is applied to the water to be treated on the raw liquid flow path 521 side with the filtration membrane 523 sandwiched between the discharge pressures. Further, the drain water treatment control of the controller 7 using a DC pump capable of changing and adjusting the conveyance flow rate for filtration by changing the number of revolutions for the purpose of proper operation (preventing idling) of the drain pump 53 in the drain water treatment. The operation is controlled by means. The DC pump constitutes a conveyance flow rate adjusting means.

  That is, the controller 7 stores in advance information on the amount of drain water generated in the secondary heat exchanger 6 based on the combustion operation, and calculates the amount of drain water derived from the drain pan 61 based on this information. By controlling the operation of the drain pump 53 constituted by the DC pump based on the derived amount, the conveyance flow rate of the water to be treated with respect to the filtration membrane 523 is changed and adjusted. As the above information, the relationship between the time from the start of combustion and the amount of drain water generated is related in advance by theoretical calculation, testing, etc., depending on the temperature of water entering the water inlet 22 and the combustion capacity of the burner 8. Is. That is, based on the latent heat amount of the fuel exhaust gas coming into contact with the secondary heat exchanger 6 and the incoming water temperature or the like entering the secondary heat exchanger 6, the amount of drain water generated or the drain water is neutralized by the neutralization tank 51 or the filtration. It is data that estimates the timing derived to the tank 52, and directly, the amount of drain water generated with respect to the elapsed time axis from the start of the combustion operation, the operation control amount (rotation speed control amount) of the drain water pump 53, and Is stored in the controller 7 (relation table). Then, the controller 7 is set so that drain water is generated after the combustion operation is started and reaches the neutralization tank 51 and the filtration tank 52 where the water is collected and the stock solution flow path 521 side becomes almost full. The elapsed time is counted by a timer, and when the time is up, operation of the drain pump 53 is started. Then, the operation control (rotational speed control) of the drain pump 53 is executed so that the conveyance flow rate becomes the flow rate according to the drain water generation amount determined based on the above information. In short, the amount of drain water generated matches the conveyance flow rate for the filtration process in the filtration tank 52. As described above, the drain pump 53 can be operated so that the amount of drain water generated, that is, the conveyance flow rate according to the amount of drain water supplied to the drain water treatment circuit 5, can be generated. In addition to being surely avoidable, it is possible to apply pressure when performing filtration on the raw solution flow path 521 side of the filtration tank 52. It should be noted that the operation control of the drain pump 53 based on the above relationship table may be changed in real time with respect to the passage of time, or may be changed step by step every predetermined time.

  Here, for further accuracy, a relatively small-capacity buffer tank 55 is provided in the lead-out pipe 82 between the neutralization tank 51 and the drain pump 53, and a water level detecting means (for example, a water level electrode or a float switch) is provided in this. The drain pump 53 may be controlled based on a water level detection signal (drain water amount detection signal) from the water level detection means. For example, the controller 7 monitors the water level detection signal from the start of the combustion operation, and starts the operation of the drain pump 53 when the stored water level becomes a predetermined water level or higher. The operation of the drain pump 53 is controlled so that the corresponding conveyance flow rate is obtained.

  Further, when such a buffer tank 55 is installed, the operation control of the drain pump 53 is based on only the water level detection signal relating to the actual stored water level in the buffer tank 55 without using the above information (relation table). May be performed. For example, if a water level above a certain set water level is detected, the drain pump 53 is changed by a predetermined amount more than the set reference rotation speed, and if the water level is gradually lowered by this operation to detect a water level below the set water level, The drain pump 53 is changed to be decreased by a predetermined amount from the set reference rotational speed. In this case, a single water level electrode is used to detect the set water level, and the above-described operation control can be performed depending on whether the detected water level is equal to or higher than the set water level, or the set water level is not detected. The control for changing the rotational speed as described above may be executed by using two of the water level electrode on the high water level side and the water level electrode on the low water level side. Furthermore, for example, two high water level electrodes for detecting a predetermined high water level and low water level electrodes for detecting a predetermined low water level can be provided as water level detecting means. In this case, the operation of the drain pump 53 may be turned on by detecting the high water level, and the rotational speed may be gradually decreased with time, and the operation of the drain pump 53 may be turned off by detecting the low water level. . Furthermore, if an intermediate water level electrode that detects the intermediate water level between the high water level and the low water level is added and the operation of the drain pump 53 is started by detecting the high water level by the high water level electrode, the intermediate water level is detected by the intermediate water level electrode. May keep the rotation speed constant, gradually decrease the rotation speed when it falls below the intermediate water level, and stop the operation by detecting the low water level.

  Here, when installing the buffer tank 55, the downstream end of the return pipe 83 may be joined to the buffer tank 55 instead of joining the downstream portion of the neutralization tank 51. Further, in realizing the above-described change control of the transfer flow rate to the stock solution flow path 521 of the filtration tank 52, the drain pump 53 is configured by a DC pump, and the transfer flow rate is changed by changing the rotation speed. However, the present invention is not limited to this, and the drain pump 53 may be configured by an AC pump and a flow rate adjusting valve may be added. That is, the conveying flow rate adjusting means is configured by a combination of a drain pump configured by an AC pump and a flow rate adjusting valve. In this case, change control of the conveyance flow rate can be realized by ON / OFF switching control of the operation of the AC pump and flow rate change control by the flow rate adjustment valve.

  In the case of the above embodiment, all impurities such as formaldehyde and bacteria dissolved in the water to be treated can be filtered and removed by the filtration membrane 523. And only the purified water rendered harmless by this filtration can be drained to the outside through the filtration flow path 522 and the outlet pipe 84. At that time, since the drainage target is the purified water as described above, The facility can be drained as it is. Therefore, in FIG. 1, the downstream end of the outlet pipe 84 is communicated with the recirculation path 32, but the downstream end of the outlet pipe 84 may be directly extended to a general drainage facility or the like. In this case, the check valve 54 can be omitted. On the other hand, the treated water that has become concentrated water without passing through the filtration membrane 523 is returned to the downstream portion of the neutralization tank 51 by the return pipe 83, mixed with the neutralized drain water, diluted, and filtered again. The filtration process can be repeated by circulating in the tank 52. At this time, the neutralized drain water can be pushed out from the neutralization tank 51 by the above merging / mixing and can be flowed to the filtration tank 52 together with the concentrated water for filtration. In addition, when draining using the recirculation circuit 32 as a drainage destination from the lead-out pipe 84, draining from the bathtub drainage port through the bathtub or branching before entering the bathtub, What is necessary is just to make it drain to the bathtub pan installed in the lower side. Alternatively, since the water drained from the outlet pipe 84 is purified water, it can be reused as bathtub water.

Second Embodiment
FIG. 3 shows a latent heat recovery heat source machine according to the second embodiment of the present invention. The second embodiment is different from the first embodiment in that a bypass pipe 56 is added as a bypass path that bypasses the filtration tank 52 and the controller 7 includes a maintenance mode in which concentrated water is discharged through the bypass pipe 56. Since the other components are the same as those in the first embodiment except for the additional execution, the same components are denoted by the same reference numerals and detailed description thereof is omitted.

  The drain water treatment circuit 5 a according to the second embodiment includes a bypass pipe 56. That is, a three-way switching valve 57 as a switching means is interposed in the outlet pipe 82 between the drain pump 53 and the filtration tank 52, and the upstream end of the bypass pipe 56 branches from the outlet pipe 82 by the three-way switching valve 57. The downstream end communicates with the outlet pipe 84 between the filtration tank 52 and the check valve 54.

  In the three-way switching valve 57, the bypass pipe 56 side is normally closed, and the discharge side of the drain pump 53 and the stock solution flow path 521 (see FIG. 2) of the filtration tank 52 are maintained in communication. When the concentrated water accumulated in the buffer tank 55 is discharged, the controller 7 is switched to a state where the discharge side of the drain pump 53 and the bypass pipe 56 communicate with each other by the operation control from the controller 7. Such switching means is not limited to the three-way switching valve 57, and may be configured by combining a plurality of electromagnetic on-off valves, for example.

  In the second embodiment, the downstream end of the return pipe 83a is connected to the buffer tank 55 so as to join, and the neutralized drain water flowing down from the neutralization tank 51 in the buffer tank 55; The concentrated water returned from the return pipe 83a is mixed, and this mixed water is circulated and supplied to the filtration tank 52 as the water to be treated as a target for filtration.

  The following control is executed as the drain water treatment control by the drain water treatment control means of the controller 7. That is, when the combustion operation is started in the burner 8, latent heat recovery is performed in the secondary heat exchanger 6 to generate drain water, and this drain water passes through the drain pan 61 and the outlet pipe 81, and the neutralization tank 51. Will be introduced. Then, the neutralized drain water overflowed when the neutralization tank 51 is filled with water flows down to the buffer tank 55 through the outlet pipe 82 and is stored. When the neutralized drain water stored in the buffer tank 55 is detected by the high water level side water electrode 551, the operation of the drain pump 53 is started by the controller 7, whereby the neutralized drain water is collected. Is flowed under pressure into the undiluted solution channel 521 (see FIG. 2) of the filtration tank 52 as water to be treated. The purified water filtered through the filtration membrane 523 is drained downstream from the outlet pipe 84, while the water to be treated that has not passed through the filtration membrane 523 becomes concentrated water through the return pipe 83a to the buffer tank 55. Will be returned to. Thereafter, the water to be treated, in which the neutralized drain water and the concentrated water are mixed in the buffer tank 55, is circulated and supplied to the raw solution flow path 521 of the filtration tank 52, and the filtration process is repeated.

  When the combustion operation of the burner 8 is stopped, the generation of drain water is also terminated after a lapse of a certain time, so the controller 7 stops the operation of the drain pump 53. Thereafter, while the combustion operation is stopped, for example, an operator who performs maintenance inputs, for example, an instruction to shift to the maintenance mode on the remote controller 7a or the input operation unit of the controller 7, whereby the controller 7 performs the drain water treatment control. As a part, processing related to the next maintenance mode is executed. In this maintenance mode, a process of draining the concentrated water accumulated in the buffer tank 55 from the bypass pipe 56 is performed by the drain water treatment (filtration process). That is, the controller 7 receives the output of the transition command to the maintenance mode and switches the three-way switching valve 57 so that the discharge side of the drain pump 53 and the bypass pipe 56 communicate with each other, and then operates the drain pump 53. Let Accordingly, the concentrated water accumulated in the buffer tank 55 is discharged through the three-way switching valve 57 and the bypass pipe 56. If it is detected that the water level in the buffer tank 55 has dropped and the water level cannot be detected even with the low water level electrode 552, that is, the buffer tank 55 has been emptied, the operation of the drain pump 53 is stopped. The three-way switching valve 57 is switched to the original state (the state in which the discharge side of the drain pump 53 and the filtration tank 52 are in communication), and for example, the remote control unit 7a displays on the display unit that the processing related to the maintenance mode has been completed. Alternatively, the drain water treatment control is switched from the maintenance mode to the normal control after notifying the operator or the like with a voice guide.

  In the case of this second embodiment, the maintenance mode can be executed in a period in which the combustion operation is stopped and there is no generation of drain water, thereby discarding the unfiltered concentrated water generated by the previous drain water treatment. In addition, it is possible to reliably perform the next drain water treatment, and avoid the shortening of the life of the filtration membrane 523 due to the continued increase in the concentration degree of the concentrated water. It becomes possible to increase the durability.

  A dedicated drainage channel to the drainage facility outside the machine is installed at the downstream end of the outlet pipe 84 from which the concentrated water is discharged, and the concentrated water in the maintenance mode is drained through this drainage channel. You may do it. Alternatively, the dedicated drainage channel may be detachably connected to an appropriate position of the outlet pipe 84 when the concentrated water is drained in the maintenance mode. Further, the execution of the process related to the maintenance mode may be performed by an automatic process without depending on the operator's input operation as described above. In that case, the drainage processing related to the maintenance mode may be executed after detecting the drainage timing that does not cause any inconvenience even when draining. When the drainage destination is a tub-side facility, the timing when the tub is not used is detected, for example, the detection that there is no remaining water, and in addition to this, all combination conditions such as time zone conditions such as midnight are satisfied. It is only necessary to determine the drainage timing after detecting the timing. The detection of the absence of residual water can be detected by, for example, the fact that the water flow switch 34 is inactive even when the circulation pump 33 of the recirculation circuit 32 is operated, or if the bathtub is equipped with an automatic drain plug, it is opened. What is necessary is just to detect that it is in a state.

It is a mimetic diagram showing a 1st embodiment of the present invention. It is sectional explanatory drawing which shows the principle of a filtration tank. It is a figure corresponding to FIG. 1 which shows 2nd Embodiment.

Explanation of symbols

5 Drain water treatment circuit 6 Secondary heat exchanger 7 Controller (control means)
8 Burners 21, 31 Primary heat exchanger 51 Neutralization tank 52 Filtration tank (reverse osmosis membrane)
53 Drain pump (conveying flow rate adjusting means)
54 Check valve 55 Buffer tank 56 Bypass pipe (bypass path)
57 Three-way selector valve (switching means)
83, 83a Return pipe (return path)
84 Lead pipe (lead path)
521 Stock solution channel 522 Filtration channel 523 Filtration membrane

Claims (8)

A primary heat exchanger that recovers sensible heat from the combustion gas generated by combustion of the burner, a secondary heat exchanger that recovers latent heat from the flue gas after passing through the primary heat exchanger, and the secondary heat exchanger A latent heat recovery heat source device comprising a drain water treatment circuit for treating drain water generated in
The drain water treatment circuit is
A neutralization tank for neutralizing the drain water, a filtration tank for filtering the neutralized drain water after being neutralized by the neutralization tank as treated water, and the treated water for the filtration tank A drain pump for supplying and discharging, and a return path for returning the unfiltered treated water from the filtration tank to the downstream portion of the neutralization tank,
The filtration tank includes a filtration membrane, and purified water filtered through the filtration membrane is discharged downstream, while unfiltered water that does not pass through the filtration membrane passes through the return path. A latent heat recovery heat source machine configured to be returned. The latent heat recovery heat source machine according to claim 1,
The filtration tank includes a raw liquid flow path through which treated water flows toward the return path, a filtration flow path through which filtered purified water flows downstream, and a space between the filtration flow path and the raw liquid flow path. A latent heat recovery heat source machine, comprising a filtration membrane arranged so as to partition each other along the flow path. The latent heat recovery heat source machine according to claim 1 or 2,
A latent heat recovery heat source machine, wherein the filtration tank includes a filtration membrane, and the water to be treated is configured to flow along the surface of the filtration membrane by a cross flow filtration method. The latent heat recovery heat source machine according to any one of claims 1 to 3,
A buffer tank is interposed downstream of the neutralization tank and upstream of the filtration tank, and a downstream end of the return path is provided so that the unfiltered water to be returned is returned to the buffer tank. Connected, latent heat recovery heat source machine. The latent heat recovery heat source machine according to any one of claims 1 to 4,
A conveyance flow rate adjusting means for changing and adjusting the conveyance flow rate of the water to be treated with respect to the filtration tank, and changing the conveyance flow rate of the treatment water in accordance with the amount of drain water generated by controlling the operation of the conveyance flow rate adjustment means. And a latent heat recovery heat source machine comprising a control means. The latent heat recovery heat source machine according to any one of claims 1 to 5,
A bypass passage that bypasses the filtration tank; and a switching means that can switch the discharge side of the drain pump to either the filtration tank side or the bypass path side. The filtration tank is switched by switching the switching means to the bypass path side. A latent heat recovery heat source machine that can discharge treated water to the downstream without passing through. The latent heat recovery heat source machine according to any one of claims 1 to 6,
A latent heat recovery heat source machine, wherein a check valve for preventing inflow of the purified water from the filtration tank to the downstream side in the reverse flow direction is interposed in the outlet path for discharging the purified water downstream. The latent heat recovery heat source machine according to any one of claims 1 to 7,
The filtration membrane of the filtration tank is a latent heat recovery heat source device configured by a reverse osmosis membrane.

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