JP2008121981A - Denitrifying device for water heater, and water heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water heater draining water as safer water or safely recycling it as bathtub water by eliminating nitrate nitrogen contained in drain water in the water heater of high heat efficiency utilizing the sensible heat and latent heat of combustion gas. <P>SOLUTION: Drain water condensed in a secondary heat exchanger 17 is led to an ion exchange resin part 20 where nitrate nitrogen is eliminated. The drain water is further led to a neutralization tank 22 and neutralized. The thus-treated drain water is discharged to a reheating circuit connected to a bath adapter 56 of a bathtub 55 and discharged into the bathtub 55 from the reheating circuit. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a denitrification device for a water heater and a water heater. Specifically, a water heater with a drain water treatment function that makes it possible to heat water with high thermal efficiency using the latent heat of the combustion gas, and for removing nitrate nitrogen from the drain water generated in the water heater The present invention relates to a denitrification device for a water heater.

  General water heaters only use sensible heat to heat water, but a high-efficiency water heater (condensing water heater) that improves heating efficiency by recovering latent heat in the combustion gas. Is conventionally known. Such a water heater includes a primary heat exchanger (main heat exchanger) and a secondary heat exchanger (auxiliary heat exchanger), and heats water with the primary heat exchanger and the secondary heat exchanger. In the primary heat exchanger, the water passing there and the combustion gas are heat-exchanged to heat the water by sensible heat. In the secondary heat exchanger, the water passing through the heat exchanger and the combustion gas are heat-exchanged to heat the water using latent heat. Therefore, according to this water heater, not only the sensible heat of the combustion gas but also its latent heat can be recovered and water can be heated with high efficiency.

  In a combustion apparatus equipped with such a latent heat recovery function, drain water (condensed water) containing strongly acidic acidic components and the like is generated in the secondary heat exchanger as the latent heat is recovered. Then it is necessary to discharge to the outside. Therefore, in general, this drain water is neutralized in a neutralization tank and then drained into sewage or the like.

  In addition, if all the drain water is neutralized in the neutralization tank, the neutralization tank becomes large, so some drain water is diluted with water and supplied to the bathtub together with warm water. (Patent Document 1).

  Also, in order to drain the drain water neutralized in the neutralization tank into sewage, etc., it is necessary to install a separate drain water discharge pipe between the water heater and the sewage. . For this reason, there is a water heater in which drain water subjected to neutralization treatment is discharged into a bathtub through a reheating circuit, and a drain water discharge pipe is not required (Patent Document 2).

Japanese Patent Laid-Open No. 06-272965 JP 2003-42566 A

  However, the drain water generated in the secondary heat exchanger contains nitrate nitrogen. Nitrate nitrogen is a harmful substance to the human body and the environment, such as being reported to cause health problems such as hemoglobinemia, and it is desired to drain it after removing it. In particular, when the drain water is subjected to some treatment and then sent into the bathtub to be used as bathtub water, it is extremely desirable to remove nitrate nitrogen.

  On the other hand, the conventional condensing water heater only neutralizes the strongly acidic drain water, and does not consider nitrate nitrogen.

  The present invention has been made in view of such technical problems, and an object of the present invention is to provide nitric acid contained in drain water in a high thermal efficiency water heater utilizing sensible heat and latent heat of combustion gas. An object of the present invention is to provide a water heater denitrifier and a water heater that can be drained as safer water or can be safely reused as bathtub water by removing reactive nitrogen and the like.

  In order to achieve such an object, a denitrification device for hot water supply according to claim 1 of the present invention is a denitrification device for hot water supply for denitrifying drain water generated in a hot water supply device, An ion exchange resin part for removing impurities in the drain water, a solution supply part for supplying a solution for restoring the ion exchange ability of the ion exchange resin part, and the solution from the solution supply part to the ion exchange resin part An on-off valve provided in a solution supply pipe for supplying the ion exchange capacity detector, and an ion exchange capacity detection section for detecting a decrease in ion exchange capacity of the ion exchange resin section, the ion exchange capacity detection section of the ion exchange resin section When a decrease in ion exchange capacity is detected, the on-off valve is opened to supply the solution from the solution supply unit to the ion exchange resin unit.

  In the denitrification apparatus for hot water heaters according to claim 1, since the ion exchange resin portion for removing impurities in the drain water generated in the water heater is provided, nitrate nitrogen contained in the drain water generated in the water heater Drain water can be discharged after removing harmful substances such as nitrogen and nitrite nitrogen. As an ion exchange material for removing nitrate nitrogen, nitrite nitrogen and the like, anion exchange resins, particularly Cl (chlorine) type anion exchange resins and OH type anion exchange resins are preferable.

  Further, the denitrification device for a hot water heater includes a solution supply unit that supplies a solution for restoring the ion exchange ability of the ion exchange resin unit, and a solution for supplying the solution from the solution supply unit to the ion exchange resin unit Since it has an on-off valve provided in the supply pipe and an ion exchange capacity detection unit that detects a decrease in ion exchange capacity of the ion exchange resin part, the ion exchange capacity detection part detects a decrease in ion exchange capacity of the ion exchange resin part. In this case, the on-off valve can be opened to automatically supply the solution from the solution supply unit to the ion exchange resin unit, and the ion exchange ability of the ion exchange resin unit can be maintained over a long period of time. It is possible to save the trouble of replenishing the exchange resin part with the solution.

  Furthermore, the embodiment of claim 2 of the present invention is the denitrification apparatus for hot water supply apparatus of claim 1, further comprising a neutralization tank for neutralizing the drain water from which impurities have been removed by the ion exchange resin part. . According to this embodiment, since the strongly acidic drain water can be neutralized in the neutralization tank, the drain water can be further rendered harmless.

  Furthermore, an embodiment of claim 3 of the present invention is characterized in that, in the denitrification apparatus for hot water supply apparatus of claim 1, the ion exchange resin part is constituted by an OH type anion exchange resin. According to such an embodiment, since the pH of the drain water that has been treated after passing through the ion exchange resin is close to neutrality, the neutralization tank for neutralizing the drain water is unnecessary, or the capacity is small. A neutralization tank can be used.

  According to a fourth aspect of the present invention, there is provided a water heater according to a fourth aspect of the present invention, wherein a primary heat exchanger disposed upstream of the combustion gas, a secondary heat exchanger disposed downstream of the combustion gas, and the secondary heat exchanger A drain receiver for collecting the drain water generated in the drain, an ion exchange resin part for removing impurities in the drain water collected by the drain receiver, and a solution for restoring the ion exchange capacity of the ion exchange resin part are supplied. An ion exchange capacity for detecting a decrease in the ion exchange capacity of the ion exchange resin section, and an on-off valve provided in a solution supply pipe for supplying the solution from the solution supply section to the ion exchange resin section. A detection unit, and when the ion exchange capacity detection unit detects a decrease in ion exchange capacity of the ion exchange resin unit, the on-off valve is opened to supply the solution from the solution supply unit to the ion exchange resin unit. It is characterized in that was.

  The water heater according to claim 4 includes an ion exchange resin portion that removes impurities from the drain water generated in the water heater, so that nitrate nitrogen or nitrite contained in the drain water generated in the water heater is provided. Harmful substances such as nitrogen can be removed, and drain water can be discharged safely. Also in this water heater, as an ion exchange material for removing nitrate nitrogen, nitrite nitrogen, etc., anion exchange resins, particularly Cl (chlorine) type anion exchange resins and OH type anion exchange resins are used. preferable.

  Further, the water heater is provided in a solution supply unit that supplies a solution for restoring the ion exchange capacity of the ion exchange resin unit, and a solution supply pipe for supplying the solution from the solution supply unit to the ion exchange resin unit. Open / close valve and an ion exchange capacity detection unit that detects a decrease in ion exchange capacity of the ion exchange resin part, so when the ion exchange capacity detection of the ion exchange resin part is detected by the ion exchange capacity detection part The solution can be automatically supplied from the solution supply part to the ion exchange resin part by opening the on-off valve, and the ion exchange ability of the ion exchange resin part can be maintained over a long period of time. The trouble of replenishing the solution can be saved.

  The embodiment of claim 5 is characterized in that, in the hot water supply apparatus of claim 4, a pipe for discharging the treated drain water into the bathtub is provided. According to such an embodiment, since the treated drain water can be discharged to the bathtub, piping work for draining the treated drain water into sewage or the like is not necessary, and the labor and construction at the time of installing the water heater Cost can be reduced.

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

  FIG. 1 is a schematic view showing a structure of a hot water heater for bath use (hereinafter referred to as a bath hot water heater) 10 according to the present invention. A hot water denitrifier 12, a hot water supply unit 13, and a memorial heating unit 14 are provided in the can 11 of the bath water heater 10. Although not shown, an air supply fan for supplying combustion air is provided below the hot water supply unit 13 and the reheating heater 14, and an exhaust port is opened on the upper surface of the can body 11.

  The hot water supply unit 13 includes a hot water burner 15, a primary heat exchanger 16 (main heat exchanger), and a secondary heat exchanger 17 (auxiliary heat exchanger). The gas is combusted at 15 to heat the water flowing through the secondary heat exchanger 17 and the primary heat exchanger 16. The primary heat exchanger 16 is positioned on the upstream side (downward) of the flow path of the combustion gas combusted by the hot water supply burner 15, and the secondary heat exchanger 17 is positioned on the downstream side (upward) of the flow path of the combustion gas. is doing.

  Thus, when the gas is burned by the hot water supply burner 15 while air is sent by the air supply fan, the combustion gas rises and passes through the primary heat exchanger 16 and the water and heat flowing through the primary heat exchanger 16. Exchange. The heat exchange here is heat exchange with the sensible heat of the combustion gas. The combustion gas heats water, while the temperature of the combustion gas itself decreases.

  The combustion gas that has passed through the primary heat exchanger 16 further passes through the secondary heat exchanger 17 and exchanges heat with water flowing through the secondary heat exchanger 17. Since the temperature of the combustion gas passing through the secondary heat exchanger 17 is lowered when passing through the primary heat exchanger 16, the secondary heat exchanger 17 exchanges heat with the latent heat of the combustion gas. Done. The combustion gas heats the water flowing through the secondary heat exchanger 17, while the temperature of the combustion gas itself further decreases, and the combustion gas whose temperature has decreased is discharged from the exhaust port to the outside.

  The water intake pipe 51 connected to the city water supply etc. is connected to the secondary heat exchanger 17, and the secondary heat exchanger 17 and the primary heat exchanger 16 are connected to each other by a connection pipe 52 to supply hot water such as a bathroom currant or shower. A hot water outlet pipe 54 connected to the terminal 53 is connected to the primary heat exchanger 16. As a result, the water inlet pipe 51, the secondary heat exchanger 17, the connecting pipe 52, the primary heat exchanger 16 and the hot water outlet pipe 54 are connected in series to form a main hot water supply path.

  Therefore, when the hot water supply terminal 53 is opened, water is supplied from the water inlet pipe 51. When the flow of water is detected and the hot water supply burner 15 is burned, the hot water outlet pipe 54 is heated by the secondary heat exchanger 17, and further Hot water heated by the primary heat exchanger 16 is supplied, and this hot water is discharged from the hot water supply terminal 53.

  A tracking forward pipe 57 and a tracking return pipe 58 are connected to the bus adapter 56 of the bathtub 55, and a tracking circuit is configured by the tracking forward pipe 57 and the tracking return pipe 58. The remedy heating unit 14 includes a remedy heat exchanger 59 and a remedy burner 60 disposed below the remedy heat exchanger 59. The ends of the tracking forward pipe 57 and the tracking return pipe 58 opposite to the bus adapter 56 are connected to a tracking heat exchanger 59. Accordingly, when the circulation pump 61 provided in the return return pipe 58 is operated and hot water in the bathtub 55 is circulated in the reheating circuit, the hot water in the bathtub 55 circulates in the reheating circuit and heat for renewal. Heated by the exchanger 59, the hot water temperature in the bathtub 55 is raised.

  In addition, a three-way valve 62 is provided in the middle of the hot water outlet pipe 54, and the three-way valve 62 and a follow-up pipe 57 of the reheating circuit are connected by a drop pipe 63. Therefore, when the three-way valve 62 is closed on the hot water supply terminal 53 side and switched so that the hot water supply unit 13 side and the drop pipe 63 side communicate with each other, the hot water heated in the hot water supply unit 13 falls from the tap pipe 54 to the drop pipe 63. The hot water that has flowed into the dropping pipe 63 passes through the remedy-outward pipe 57, is dropped into the bathtub 55 from the bus adapter 56, and hot water filling is performed.

  The bath water heater 10 is controlled in operation by a controller 24 configured by a microcomputer, a memory, an electronic circuit, and the like. In particular, the controller controls combustion of the hot water supply burner 15 during hot water supply while monitoring the values of various sensors not shown, and controls the circulation pump 61 and the additional burner 60 during reheating. A remote controller 29 is connected to the controller 24 so that the bath water heater 10 installed outdoors can be operated from the indoor side. The remote controller 29 is provided with an operation switch, a chase switch, a display unit 28 and the like.

  In the hot water heater 10 having high heat efficiency as described above, a part of the combustion gas is condensed in the secondary heat exchanger 17 by releasing latent heat, so that the condensed combustion is formed on the surface of the secondary heat exchanger 17. Strong acid drain water by gas adheres. Since the drain water adhering to the secondary heat exchanger 17 falls down from the secondary heat exchanger 17, the secondary heat exchanger 17 has a gap between the primary heat exchanger 16 and the secondary heat exchanger 17. A drain receiver 18 is provided for receiving the drain water falling.

  Since the drain receiver 18 is inclined, the drain water falling on the drain receiver 18 flows on the upper surface of the drain receiver 18 and is collected on one side. The drain water collected on one side of the drain receiver 18 is discharged to the drain water discharge pipe 19 and sent to the ion exchange resin portion 20 through the drain water discharge pipe 19.

  The ion exchange resin part 20 is a container in which drain water can be passed and filled with an anion exchange resin for removing nitrate nitrogen. For example, as an anion resin for removing nitrate nitrogen and the like, a Cl (chlorine) type anion exchange resin and an OH type anion exchange resin are preferable. If such an ion exchange resin part 20 is used, harmful substances (ions) such as nitrate nitrogen and nitrite nitrogen contained in drain water passing through the ion exchange resin part 20 can be adsorbed and removed. The drain water from which nitrate nitrogen or the like has been removed by the ion exchange resin portion 20 is sent to the neutralization tank 22 through the drain water discharge pipe 21.

  The neutralizing tank 22 has a neutralizing agent such as calcium carbonate, a filter, and the like inside, and neutralizes the drain water so that the pH of the drain water passing through the neutralizing tank 22 becomes almost neutral.

  The discharge port of the neutralization tank 22 is connected to an appropriate portion of the tracking forward pipe 57 by a drain discharge pipe 30. Therefore, the treated drain water from which nitrate nitrogen or the like has been removed by the ion exchange resin portion 20 and neutralized by the neutralization tank 22 is discharged to the tracking pipe 57, and is traced when the bath water is recharged. It is discharged from the tube 57 into the bathtub 55.

  Thus, by draining the treated drain water into the bathtub 55, there is no need to pipe a drain drain pipe for draining the drain water into the sewage or the like from the bath water heater 10 to the sewage. The piping work at the time of installation of 10 can be simplified. Moreover, since the drain water discharged to the bathtub 55 is neutralized so as to be neutral in the neutralization tank 22 by removing harmful substances such as nitrate nitrogen by the ion exchange resin portion 20, the human body ( The effect on the bather) and the environment can be reduced to a level with almost no problem.

  Next, regeneration of the ion exchange resin will be described. Since the ion exchange capacity of the ion exchange resin gradually decreases with use, the ion exchange resin part 20 is provided with an ion exchange capacity detection part 23 for detecting a decrease in the ion exchange capacity of the ion exchange resin. As the ion exchange capacity detection unit 23, for example, two electrodes are installed inside the ion exchange resin unit 20, the electrical conductivity of drain water between the electrodes is monitored, and the electrical conductivity is equal to or higher than a predetermined value (threshold). In this case, the determination function configured in the controller 24 determines that the ion exchange resin needs to be regenerated. The regeneration time of the ion exchange resin may be determined by the denitrification ability of the ion exchange resin. For example, the drain water electricity when the nitrate nitrogen concentration of the drain water after treatment cannot be denitrified to 10 ppm or less, which is the tap water quality standard. The conductivity may be set as a threshold value.

  A chloride solution supply unit 25 is provided in the vicinity of the ion exchange resin unit 20, and the chloride solution supply unit 25 regenerates the ion exchange resin in the ion exchange resin unit 20 to recover the ion exchange ability. Of chloride solution. The chloride solution supply unit 25 and the ion exchange resin unit 20 are connected by a solution supply pipe 26, and an open / close valve 27 is provided in the solution supply pipe 26.

  The controller 24 reads the detection value of the ion exchange capacity detector 23 and monitors the ion exchange capacity of the ion exchange resin. When the ion exchange resin needs to be regenerated, the controller 24 follows the flowchart shown in FIG. In addition, a warning is displayed on the display unit 28 of the remote controller 29, and the on-off valve 27 is opened to supply chloride from the chloride solution supply unit 25 to the ion exchange resin unit 20.

  That is, when monitoring of ion exchange capacity is started (step S1), the electrical conductivity of drain water after treatment is measured by the ion exchange capacity detector 23 (step S2). When the electrical conductivity of the drain water after treatment is measured by the ion exchange capacity detector 23, the measured value of the electrical conductivity is compared with a predetermined value (threshold value) (step S3). And if the measured electrical conductivity is smaller than a predetermined value, monitoring of ion exchange capacity will be complete | finished as it is (step S6).

  In step S3, if the measured electrical conductivity is equal to or higher than a predetermined value, it is determined that the ion exchange capacity of the ion exchange resin has decreased, and the controller 24 displays “ion exchange resin” on the display unit 28 of the remote control 29. "Regeneration warning display" is performed (step S4), then the on-off valve 27 is opened (step S5), and the chloride solution is automatically supplied from the chloride solution supply unit 25 to the ion exchange resin unit 20, and the ion exchange resin unit 20 The ion exchange resin inside is regenerated. Thereafter, the monitoring of the ion exchange capacity is terminated (step S6).

  The monitoring of the ion exchange capacity of the ion exchange resin shown in FIG. 2 may be always executed by repeating the operation of FIG. 2, but may be executed at regular intervals.

  Further, when the chloride solution in the chloride solution supply unit 25 is low, a warning is displayed on the display unit 28 of the remote controller 29 or a buzzer is sounded to inform the user of the chloride solution. Encourage replenishment. The chloride solution supply unit 25 may be installed outside the bath water heater 10 (can 11) as a separate component from the bath water heater 10. By installing the chloride solution supply unit 25 outside, the chloride solution can be easily replenished.

  Here, an example is shown. FIG. 3 shows the amount of water flow (liter) when drain water is passed through the Cl-type anion exchange resin, and the content of inorganic nitrogen (mg N / min) contained in the drain water after treatment after passing through the ion exchange resin portion 20. It is a figure which shows the relationship with liter). For this measurement, 50 mL of “Amberlite IRA400J (CL type)” (manufactured by Organo Corporation) as a Cl type anion exchange resin packed in a column having a diameter of 24 mm and a length of 100 mm was used. Then, drain water having an inorganic nitrogen concentration of 16.2 mg N / L was passed through the ion exchange resin at a flow rate of 70 mL / min.

  As can be seen from FIG. 3, the inorganic nitrogen concentration of the drain water after passing through the Cl-type anion exchange resin is about 0 mgN / L at the beginning, but the inorganic nitrogen concentration from the time when the water flow reached 25 liters. Is increasing rapidly, and it is time to replace the ion exchange resin. On the other hand, the pH of the drain water after passing through the Cl-type anion exchange resin is maintained at a value of about 3 or less.

  Also, when an OH type anion exchange resin is used as the ion exchange resin, the change in the inorganic nitrogen concentration shows the same tendency as the Cl type anion exchange resin, but the drain that has passed through the OH type anion exchange resin. The pH of water becomes a value closer to neutrality. For example, 100 mL of drain water having a pH of 2.7 was added to 30 g of Cl-type anion exchange resin, and the mixture was stirred for 1 minute and then allowed to stand to measure the pH. As a result, the pH of the drain water was 2.7. It was. On the other hand, after adding 100 mL of drain water having a pH of 2.7 to 30 g of OH type anion exchange resin and stirring for 1 minute, this was left to stand and measured for pH. As a result, the pH of the drain water was 8. It became 1.

  Thus, when the OH type anion exchange resin is used as the ion exchange resin, the pH of the drain water after the treatment becomes close to neutral. Therefore, when the OH type anion exchange resin is used in the ion exchange resin part 20, It is possible to eliminate the neutralization tank 22 or use the neutralization tank 22 with a small capacity.

FIG. 1 is a schematic diagram showing a configuration of a bath water heater according to the present invention. FIG. 2 is a flowchart showing an operation for automatically supplying a solution for recovering the ion exchange resin to the ion exchange resin portion. FIG. 3 shows the amount of water flow (liter) when drain water is passed through the Cl-type anion exchange resin, and the content of inorganic nitrogen (mg N / min) contained in the treated drain water after passing through the ion exchange resin portion. It is a figure which shows the relationship with liter).

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Bath water heater 12 Hot water denitrifier 15 Hot water burner 16 Primary heat exchanger 17 Secondary heat exchanger 18 Drain receiver 19 Drain water discharge pipe 20 Ion exchange resin part 21 Drain water discharge pipe 22 Neutralization tank 23 Ion exchange capacity detection unit 24 Controller 25 Chloride solution supply unit 26 Solution supply pipe 27 On-off valve 28 Display unit 29 Remote control 30 Drain discharge pipe

Claims (5)

A denitrification device for a water heater for denitrifying drain water generated in a water heater,
An ion exchange resin part for removing impurities in the drain water, a solution supply part for supplying a solution for restoring the ion exchange ability of the ion exchange resin part, and the solution from the solution supply part to the ion exchange resin part An on-off valve provided in a solution supply pipe for supplying the ion exchange resin, and an ion exchange capacity detection unit that detects a decrease in ion exchange capacity of the ion exchange resin part. A denitrification device for a hot water supply apparatus that opens the on-off valve to supply the solution from the solution supply unit to the ion exchange resin unit when a decrease in ion exchange capacity is detected.   The denitrification apparatus for hot water heaters of Claim 1 provided with the neutralization tank which neutralizes the drain water from which the impurity was removed by the said ion exchange resin part.   The denitrification device for a hot water heater according to claim 1, wherein the ion exchange resin portion is made of an OH type anion exchange resin. A primary heat exchanger disposed upstream of the combustion gas;
A secondary heat exchanger disposed downstream of the combustion gas;
A drain receiver for collecting drain water generated in the secondary heat exchanger;
An ion exchange resin part for removing impurities in the drain water collected by the drain receiver;
A solution supply unit for supplying a solution for restoring the ion exchange capacity of the ion exchange resin unit;
An on-off valve provided in a solution supply pipe for supplying the solution from the solution supply unit to the ion exchange resin unit;
An ion exchange capacity detection unit for detecting a decrease in ion exchange capacity of the ion exchange resin part,
A water heater that opens the on-off valve to supply the solution from the solution supply unit to the ion exchange resin unit when the ion exchange capability detection unit detects a decrease in ion exchange capability of the ion exchange resin unit.   The hot water supply device according to claim 4, comprising a pipeline for discharging the treated drain water into the bathtub.

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