JP5741824B2 - Water leak detection system - Google Patents

Description

  The present invention relates to a leak detection that detects a leak that may occur due to damage to an internal partition that separates the two liquids in a heat exchanger that exchanges heat between the liquid on the heat source side and the liquid on the heating target side. In particular, the present invention relates to a technology that can avoid the possibility of erroneous determination due to a malfunction on the water leakage detection system side.

  Conventionally, in Japanese Patent Application Laid-Open No. 2004-133620, the present applicant has disclosed a hot water supply apparatus or cogeneration system that uses the heat medium in the primary side circulation circuit as a heat source and heat exchange heats the heat medium in the secondary side circulation circuit with a heat exchanger. In a system (hereinafter referred to as “cogeneration system”), a heat exchanger breakage detection device for detecting the occurrence (for example, perforation) of the internal partition wall of the heat exchanger is proposed. In this case, when the damage occurs in the heat exchanger, the heat medium in the primary side circulation circuit having a high internal pressure leaks into the secondary side circulation circuit, and enters the expansion tank interposed in the secondary side circulation circuit. Inflow and overflow of the expansion tank, a storage container that temporarily stores the overflowed heat medium is installed, and the heat exchanger is damaged based on the output from the liquid level sensor that detects the liquid level in the storage container. Is detected. More specifically, the storage container is provided with a discharge path that can be discharged at a high flow rate when the temporary storage amount of the heat medium is equal to or higher than a predetermined high water level, while a predetermined small amount is provided at a low water level near the bottom. A suppression discharge path that allows only discharge at each flow rate is provided. When the heat exchanger breaks down, the temporary storage amount above the low water level is continued for a predetermined time without catching up with the discharge through the suppression discharge channel. When the continuation of the temporary storage amount is detected by the liquid level sensor, it is determined that the heat exchanger is broken.

JP 2005-241119 A

  However, if it is attempted to detect the occurrence of water leakage through the heat exchanger from the primary side to the secondary side by applying the principle of the heat exchanger breakage detection device described above, an erroneous determination is caused due to the occurrence of a failure in the detection mechanism. May occur. That is, in the heat exchanger breakage detection device, since a small opening portion or a constriction portion is provided as the suppression discharge path so that a predetermined small flow rate can be passed, the suppression discharge path has some sort of If clogging or the like occurs due to the cause and the discharge becomes impossible, the state of the temporary storage amount above the low water level level will continue even if the heat exchanger is not damaged. As a result, there is a possibility that it may be erroneously determined that the heat exchanger is broken although the heat exchanger is not broken.

  The present invention has been made in view of such circumstances, and the object of the present invention is to accurately detect the occurrence of water leakage due to damage to the heat exchanger without erroneous determination even if the above-mentioned clogging or the like occurs. Another object is to provide a water leakage detection system that can detect water leakage.

In order to achieve the above object, in the present invention, a heat medium in both circuits between a primary circuit in which the internal pressure is high and a secondary circuit in which an expansion tank is interposed and the internal pressure is low is provided. Applied to a system equipped with a heat exchanger that exchanges liquid-liquid heat, a leak detector that temporarily stores the heat medium that has overflowed from the expansion tank, and detection of occurrence of a set residence state of the heat medium in the leak detector Thus, the following specific matters are provided for a water leakage detection system including a water leakage detection processing unit that determines that water leakage has occurred between both circuits via the heat exchanger. That is, example Preparations and liquid level sensing means for sensing the liquid level in the expansion tank, and a leakage determination correction means for correcting the processing of the determination result of the leakage occurrence based on the liquid level detection by the liquid level detector In addition, as the water leakage determination correction means, even when the occurrence of the set residence state of the heat medium is detected in the water leakage detection unit when the liquid level detected by the liquid level detection means is equal to or lower than a set liquid level, It is determined that a passage blockage has occurred in the water leakage detection unit or a downstream discharge path from the water leakage detection unit, and a notification process related to the occurrence of the error is performed. (Claim 1).

  In the case of the present invention, even if the set retention state of the heat medium occurs in the water leakage detection unit and the situation where it is determined that water leakage has occurred, the liquid level situation on the expansion tank side by the liquid level detection means ( If the detected liquid level is lower than the set liquid level at which overflow cannot occur, for example, correction processing is performed on the determination result of the occurrence of water leakage, that is, the determination of the occurrence of water leakage is canceled or the occurrence of water leakage occurs. Therefore, it is possible to reliably avoid the occurrence of erroneous determination in the water leakage detection process, and to avoid unnecessary maintenance work based on the erroneous determination. Is possible.

In addition, since the a configuration in which the leakage passage blocking the discharge passage downstream from the detection unit or a leak detection unit is determined to have occurred, executing the notification process according to the error of that effect, leakage In addition to being able to reliably avoid the occurrence of misjudgment in the detection process, whether or not the occurrence of the set retention state of the heat medium in the water leakage detection unit is caused by leakage of the heat exchanger, It is possible to reliably distinguish whether it is caused by passage blockage (clogging) in the water leakage detection section or in the downstream discharge passage. In addition, when a passage blockage occurs, this can be accurately notified to the user or a maintenance worker, and subsequent maintenance can be greatly facilitated.

  As described above, according to the water leakage detection system of the present invention, even if the set retention state of the heat medium occurs in the water leakage detection unit and it is determined that water leakage has occurred, Based on the liquid level situation (detected liquid level) on the expansion tank side by the position detecting means, it is possible to correct the determination result that water leakage has occurred. As a result, it is possible to reliably avoid occurrence of erroneous determination in the water leakage detection process, and to avoid forced maintenance work based on the erroneous determination.

In addition , whether the occurrence of the set residence state of the heat medium in the water leakage detection unit is caused by the leakage of the heat exchanger, or a blockage of the passage in the water leakage detection unit or in the downstream discharge path has occurred. It is possible to reliably distinguish whether it is a cause or a cause. In addition, when a passage blockage occurs, the user or maintenance worker can be accurately notified of this, and the subsequent maintenance can be greatly facilitated.

It is a mimetic diagram showing an example of a cogeneration system to which a water leak detection system concerning an embodiment of the present invention is applied. 2A is an enlarged cross-sectional explanatory view of the storage container of the water leakage detection system of FIG. 1, and FIG. 2B is a partially enlarged view of FIG. 3 (a) is a partial perspective view of FIG. 2 (b), and FIG. 3 (b) is a view corresponding to FIG. 2 (b) showing another aspect that can be substituted for the configuration of FIG. 2 (b). It is a block diagram of the control composition concerning water leak detection in a controller. It is a control flowchart concerning water leak detection.

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

  FIG. 1 shows a cogeneration system to which a water leakage detection system R according to an embodiment of the present invention is applied. The cogeneration system includes a power generation system E, a hot water supply / heating system W, and a controller C that controls the operation of each of the systems E, W, R. The exhaust heat generated with the above is used as a heat source in the hot water supply / heating system W. First, an outline of the configuration of the cogeneration system will be described.

  The power generation system E circulates between the gas engine 11 in which the power generation operation is performed by the drive and the heat exchanger 31 for exhaust heat recovery using the engine coolant in the gas engine 11 as a heat source heat medium. A circulation circuit 12 is provided, and a circulation pump 13 and an expansion tank 14 are interposed in the first circulation circuit 12. When the power generation operation is performed by driving the gas engine 11, the electric power generated by the power generation operation is supplied to the electrical equipment, while the engine cooling water heated by the drive is first circulated to the heat exchanger 31. Circulating and supplied through the circuit 12, the heat exchanger 31 heats the circulating hot water in the second circulation circuit 32 on the hot water supply / heating system W side by liquid-liquid heat exchange using the engine cooling water as a heat source. Thereby, exhaust heat recovery of the gas engine 11 is performed.

  The expansion tank 14 is provided with two water level electrodes 141 and 142 for low water level and high water level as a liquid level detecting means, and for overflowing when the liquid level rises above a predetermined liquid level. An overflow pipe 15 is connected. When the heat medium in the first circulation circuit 12 is reduced to a predetermined amount or less, the heat medium is automatically replenished under the control of the controller C. That is, when it is detected by the signal output from the water level electrode 141 that the liquid level in the expansion tank 14 is lower than the low water level, the supply path 16 for supplying the heat medium is controlled to open the heat medium (for example, engine cooling water). The anti-freezing liquid) is replenished, and when it is detected by the signal output from the water level electrode 142 that the liquid level has recovered to a high water level (set liquid level), the replenishment is stopped. The downstream end of the overflow pipe 15 is extended to a later-described storage container 51 of the water leak detection system R so that the overflowed heat medium flows into the storage container 51.

  The hot water supply / heating system W is composed of a combination of a hot water storage hot water supply device that uses the exhaust heat of the power generation system E as a heat source and a hot water heating device that uses the heat of the hot water stored on the hot water supply device side as a heat source. Yes. As a configuration on the side of the hot water supply device, the engine cooling water is taken out in the liquid-liquid heat exchange type heat exchanger 31 by taking out the hot water in the hot water storage tank 2 from the bottom 21 by the operation of the sealed hot water storage tank 2 and the circulation pump 30. From the second circulation circuit 32 for storing heat as hot water in the hot water storage tank 2 by recovering the exhaust heat of the heat and returning it to the top portion 22, the water supply circuit 33 for supplying tap water from the outside, and the hot water storage tank 2. And a hot water supply circuit 36 for supplying hot water to the hot water tap 35 using hot water after auxiliary heating from the auxiliary heat source 34. In addition, the auxiliary heat source machine 34 is comprised, for example by the instantaneous type water heater.

  The water supply circuit 33 has an upstream end connected to an external water pipe or the like, and a downstream end connected to the vicinity of the bottom of the hot water storage tank 2 via a check valve to supply water to the hot water storage tank 2 or through a branch water supply path 37. It is possible to supply water to the hot water supply circuit 36 side. When the hot water tap 35 is opened and hot water is supplied from the hot water supply circuit 36, the hot water from the hot water storage tank 2 or the hot water after auxiliary heating from the auxiliary heat source unit 34 is mixed with the water supplied from the branch water supply channel 37. The temperature of the valve 38 is adjusted by mixing at a predetermined mixing ratio, and then the hot-water tap 35 is supplied with hot water. The controller C performs various operation controls such as operating the auxiliary heat source unit 34 in accordance with the hot water storage temperature in the hot water storage tank 2 in the above operation and controlling the temperature by mixing control by the mixing valve 38. Yes.

  Further, as a configuration on the side of the hot water heater, for example, a third circulation circuit 41 that circulates and supplies a heat medium (for example, an antifreeze such as ethylene glycol) of a heating heat source to an external heating terminal 40 such as floor heating is provided. ing. The third circulation circuit 41 is provided with a liquid-liquid heat exchange type heat exchanger 42, a circulation pump 43, and an expansion tank 44. In the heat exchanger 42, hot water heat-exchanged and heated by the heat exchanger 31 of the second circulation circuit 32 or hot water auxiliary-heated by the auxiliary heat source device 34 on the downstream side of the heat exchanger 31 is circulated and supplied as a heat source. The heating medium is heated by heat exchange by the hot water on the hot water storage type hot water supply apparatus side (see the arrow of the one-dot chain line in FIG. 1). When the heating request from the heating terminal 40 is output to the controller C, the circulation pump 43 is operated, and the heat medium is circulated and supplied between the heat exchanger 42 and the heating terminal 40. The heat medium heated at is supplied to the heating terminal 40 and radiated, and the heat medium cooled by the heat radiation is returned to the heat exchanger 42 and reheated.

  The expansion tank 44 has the same configuration as the expansion tank 14 of the power generation system E. That is, in the expansion tank 44, two water level electrodes 441 and 442 for low water level and high water level are installed as liquid level detection means, while overflowing when the liquid level rises above a predetermined liquid level. The overflow pipe 45 is connected. When the heat medium in the third circulation circuit 41 is reduced to a predetermined amount or less, the heat medium is automatically replenished under the control of the controller C. When it is detected by the signal output from the water level electrode 441 that the liquid level in the expansion tank 44 has fallen below the low water level, the supply medium 46 is controlled to open the supply path 46 for supplying the heat medium, and the water level electrode 442 is supplied. If it is detected that the liquid level has recovered to a high water level (set liquid level) by the signal output from, the replenishment is stopped. The downstream end of the overflow pipe 45 is extended to the storage container 51 of the water leakage detection system R so that the overflowed heat medium flows into the storage container 51.

  The water leakage detection system R includes a storage container 51 that temporarily stores a heat medium that overflows in the expansion tanks 14 and / or 44 and is introduced by the overflow pipes 15 and 45, and a heat medium that is temporarily stored in the storage container 51. The water leakage electrode 52 comprised of the liquid level electrode for detecting the liquid level of the liquid and the discharge part 53 for discharging the heat medium temporarily stored in the storage container 51 in two discharge forms. As shown in FIGS. 2A, 2B, and 3A, the discharge unit 53 includes a cylindrical main body 531 that vertically penetrates the bottom wall 511 of the storage container 51. Are opened to the upper and lower sides of the open discharge passage 532 set to have a relatively large inner diameter, and restrained to open to the side of the cylindrical main body 531 at a position slightly above the bottom wall 511 and communicate with the open discharge passage 532. A discharge path 533 is formed.

  The cylindrical main body 531 is disposed so as to protrude upward from the bottom wall 511 so that the upper end opening 532a of the open discharge path 532 is positioned at a predetermined upper limit liquid level HL. The water flow cross-sectional area of the open discharge path 532 is a value that allows passage of the heat medium having a larger flow rate than that of the suppression discharge path 533, and the temporarily stored heat medium passes from the overflow pipes 15 and 45. Even if it is introduced rapidly and in a large amount and exceeds the upper limit liquid level HL, it is set to a value that allows the heat medium in the temporarily stored state to pass at a large flow rate so that it can be discharged early. In addition, the opening position of the suppression discharge path 533 may be the upper surface (bottom surface) position of the bottom wall 511, but in order to prevent clogging by precipitating dust that may be contained in the heat medium, the bottom wall It is set to open upward from the lower limit liquid level LL slightly above the upper surface of 511.

  The opening cross-sectional area of the suppression discharge path 533 is the lower end position of the leakage electrode 52 introduced from the overflow pipes 15 and 45 if the heat storage medium has a temporary storage amount smaller than the extent caused by the heat exchanger breakage. Even if a detection signal is output from the leakage electrode 52 beyond the leakage detection liquid level RL, the flow rate is such that it can be discharged at an early stage (earlier than the elapsed time value based on the leakage detection timer described later) (for example, 50 to 200 mL). / Min) so that the heat medium can be discharged. That is, the heat medium introduced from the overflow pipes 15 and 45 to the storage container 51 is not caused by the heat exchanger breakage, and for example, condensed water may be generated on the inner surfaces of the overflow pipes 15 and 45. In addition, if the amount is a slight amount due to excessive replenishment due to a delay in the stoppage of replenishment from the replenishment passages 16 and 46 to the expansion tanks 14 and 44, water leakage is detected by discharging the heat medium at an early stage. Is not determined. The water leakage detection unit is configured by the storage container 51 having such a discharge unit 53. And the situation of the amount of temporary storage of the heat medium in this water leak detection part is grasped | ascertained by the water leak electrode 52, and the occurrence of the heat exchanger breakage of the heat exchangers 31 and / or 42 (for example, perforation of the internal partition wall) It is possible to determine that the resulting water leakage has occurred. That is, as a result of the overflow of the expansion tanks 14 and 44 due to breakage of the heat exchanger, the heat medium that is temporarily stored in the storage container 51 is not exhausted from the suppression discharge path 533 and is set to a predetermined setting. If it reaches the staying state (set staying state) that the liquid level is maintained higher than the water leakage detection liquid level RL for more than the time, it is possible to detect that water leakage due to the heat exchanger breakage has occurred. is there.

  Here, in the state where the hot-water tap 35 is closed and the hot-water supply operation by the hot-water supply circuit 36 is stopped, the inside of the second circulation circuit 32 is dominated by the supply water pressure, so that it is opened by the expansion tanks 14 and 44. The internal pressure in the second circulation circuit 32 is higher than the internal pressure in the first or third circulation circuit 12, 41. For this reason, if the heat exchanger breaks in the heat exchangers 31 and 42, the hot water in the second circulation circuit 32 having a high internal pressure continuously leaks into the first or third circulation circuits 12 and 41. become. When water leakage occurs, the liquid level in the expansion tanks 14 and 44 rises and overflows, and the overflowing heat medium or the like is introduced into the storage container 51 through the overflow pipes 15 and 45. Therefore, by detecting the occurrence of such water leakage at an early stage, the occurrence of a problem that hot water in the second circulation circuit 32 is mixed with the heat medium in the first or third circulation circuit 12, 41 as much as possible. It becomes possible to keep it small, or to grasp the occurrence of breakage of the heat exchanger at an early stage and perform maintenance.

  As shown in FIG. 4, the controller C includes a water leakage detection processing unit 6, and the water leakage detection processing unit 6 includes a water leakage detection processing unit 61 and a water leakage determination correction unit 62 as a water leakage determination correction unit. The water leakage detection processing unit 61 and the water leakage determination correction unit 62 are configured to detect water leakage based on signal outputs from the water leakage electrode 52 in the storage container 51 and the water level electrodes 142 and 442 for the expansion tanks 14 and 44, particularly for high water levels. Performing a determination of detection to perform a notification process for the remote controller 63 as a notification means, or detecting a water leak by detecting a false water leak caused by clogging in the suppression discharge path 533 instead of the occurrence of water leak Detection correction processing is performed.

  Hereinafter, the processing by the water leakage detection processing means 6 will be described with reference to FIG. First, it is determined whether or not the leakage electrode 52 continues to be ON for a predetermined set time (step S1). Specifically, if an ON signal is output from the water leakage electrode 52, a water leakage detection timer using an electronic clock is started, and if the ON signal continues until the set time elapses, the ON state continues (the set residence state is maintained). It is determined that there is a possibility of water leakage (YES in step S1). Next, it is determined whether or not the ON signal is output from the water level electrodes 142 and 442 of the expansion tanks 14 and 44 (step S2). If an ON signal is output from either of the water level electrodes 142 and 442 (YES in step S2), the liquid level of the heat medium in the expansion tank 14 or 44 rises and overflows. Since the ON state continues, the determination that water leakage has occurred due to heat exchanger breakage (heat exchanger perforation) is confirmed, and notification processing for the remote control 63 serving as notification means is performed (step S3).

  On the other hand, if no ON signal is output from either of the water level electrodes 142 and 442 in step S2 (NO in step S2), it is determined that a discharge abnormality has occurred (the leakage detection unit is clogged), and the leakage electrode 52 is in the ON state. However, even if it continues for a set time, the determination that there is a possibility of occurrence of water leakage is canceled so that the determination that water leakage has occurred is not performed. A notification process or the like is performed (step S4). That is, since the temporary storage amount higher than the water leakage detection liquid level RL at which the water leakage electrode 52 is turned on continues even though the expansion tanks 14 and 44 do not overflow, it includes the suppression discharge path 533. This is because the discharge path is clogged, and it is determined that the heat exchanger is not broken.

  According to the above leakage detection processing, even if the temporary storage amount in the storage container 51 continues to be higher than the leakage detection liquid level RL at which the leakage electrode 52 is turned on, the situation on the expansion tanks 14 and 44 side is maintained. By checking the output status of the water level electrodes 142 and 442 (whether or not an overflow has occurred), whether or not the status of the temporary storage amount is a leak due to a heat exchanger breakage, It is possible to reliably distinguish whether it is caused by clogging of the suppression discharge path 533 or the like. Accordingly, it is possible to reliably avoid the occurrence of erroneous determination in the water leakage detection process, and it is possible to avoid being forced to perform useless maintenance work based on the erroneous determination. In addition, when clogging occurs (passage blockage), it can be accurately notified to the user or maintenance worker, and the subsequent maintenance can be greatly facilitated.

<Other embodiments>
In addition, this invention is not limited to the said embodiment, Other various embodiment is included. That is, instead of the suppression discharge path 533 of the discharge unit 53 in the above embodiment, a discharge unit 53a as shown in FIG. 3B may be applied. This discharge part 53a forms the constriction part in the middle of the discharge path, and comprises the suppression discharge path 533a by this constriction part. The suppression discharge path 533a is also throttled so as to have a flow rate similar to that of the suppression discharge path 533 of the embodiment.

  In addition, the application target of the present invention only needs to have at least the following configuration. That is, a liquid-liquid heat exchange type heat exchanger is provided, and when a heat exchanger breakage such as a hole in the internal partition wall occurs, the heat medium leaks from the high internal pressure side to the low side, and the leaked water flows into the side. The present invention can be applied if the heat medium overflowing from the expansion tank interposed in this circuit is introduced into the storage tank 51 of the water leakage detection system R.

6 Water leakage detection processing means 14, 44 Expansion tank 15, 45 Overflow pipe 31, 42 Heat exchanger 51 Storage container (water leakage detection part)
52 Leakage electrode 53 Discharge part (leakage detection part)
61 Water leakage detection processing unit 62 Water leakage determination correction unit (water leakage determination correction means)
63 Remote control (notification means)
142,442 Water level electrode (liquid level detection means)

Claims (1)

A heat exchanger is provided for liquid-liquid heat exchange of the heat medium in both circuits between the primary circuit where the internal pressure is high and the secondary circuit where the expansion tank is interposed and the internal pressure is low. Applied to the system, a leakage detector that temporarily stores the heat medium overflowed from the expansion tank, and both circuits via the heat exchanger by detecting the occurrence of a set residence state of the heat medium in the leakage detector A water leakage detection system comprising a water leakage detection processing means for determining that there is water leakage between
A liquid level detecting means for detecting the liquid level in the expansion tank;
A water leakage determination correcting means for correcting the determination result of the occurrence of water leakage based on the liquid level detection by the liquid level detecting means;
With
The leakage determination correction means, can the sensing liquid level by the liquid level detecting means is equal to or less than the set hydraulic position, even when detecting the occurrence of setting the residence state of the water leakage detecting portion by the heat medium, the determination of the water leakage occurred without, determined from the previous SL in water leakage detecting unit or a water leakage detection unit and the passage blocking the discharge passage on the downstream side is generated, it is configured to perform the notification process according to the error of that effect The
Water leakage detection system, characterized in that.

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