JP4636325B2 - Heating device - Google Patents

Description

  The present invention relates to a heating device that heats a liquid by exchanging heat with combustion gas generated in a combustion burner, and more particularly to a device provided with a plurality of heat exchanging means.

  Conventionally, there is a heating device as disclosed in Patent Document 1 below. The heating device disclosed in Patent Document 1 below employs a so-called latent heat recovery type heating mode, and has a configuration in which a plurality of heat exchangers are arranged in a passage through which combustion gas passes.

  Conventionally, as disclosed in the following Patent Document 2, the pipe is formed in the middle of a flow path configured by connecting the pipe to the heat exchanger by bending the pipe into a substantially “U” shape. Some have a trap structure. In the heating device having such a configuration, in order to prevent the liquid remaining in the interior from freezing when the liquid flow is stopped, a liquid draining means is provided in the trap structure or the like so that the liquid can be discharged when the liquid flow is stopped. Many have been configured.

JP-A-11-148642 JP 2000-18709 A

  As for the heating apparatus adopting the heating mode called the latent heat recovery type disclosed in Patent Document 1, the liquid freezes when the liquid flow is stopped, as in the heating apparatus disclosed in Patent Document 2. In order to prevent this, there is a configuration provided with drainage means. In such a configuration, if the draining operation is performed to drain the liquid remaining in the primary heat exchanger, the secondary heat exchanger, etc. by operating the draining means, it is possible to eliminate problems caused by freezing of the liquid. It is assumed that there is.

  However, in the latent heat recovery type heating device, the heat exchange system configured by connecting the primary heat exchanger and the secondary heat exchanger tends to be long or complicated. Therefore, even if a draining means is provided and the draining operation is performed as in the prior art, all of the liquid remaining in the primary heat exchanger and the secondary heat exchanger is not always removed during the draining operation. However, there is a high possibility that a part of the liquid gradually gathers in a low place over time after completing the draining operation. Therefore, in the prior art latent heat recovery type heating device, when the drainage operation is completed when most of the liquid is removed, the hot water still remaining in the heat exchange system is collected without being discharged into the staying part. , May freeze.

  Here, many of the conventional heating devices are provided with detection means for detecting the liquid flow in the heat exchange system, and the combustion burner is operated on condition that the liquid flow is detected by the detection means. ing. Therefore, if freezing occurs in the state where the liquid remains in the retention portion as described above, even if the liquid is supplied via the heat exchange system for hot water supply or the like, the liquid cannot reach the detection means, and the combustion burner May not work properly.

  Further, in the case of a configuration like the heating device disclosed in Patent Document 2, there is a bypass flow path connecting the upstream side and the downstream side of the trap structure part, so that the frozen trap structure part is bypassed. Liquid flows. For this reason, in the state where the liquid flows through the bypass flow path, the combustion burner will operate if a detection means for detecting the liquid flow is provided on the downstream side in the liquid flow direction. However, in this case, since the liquid does not reach the heat exchanger and may be empty, there is a problem that when the combustion burner is operated, a so-called emptying state occurs.

  Therefore, in the present invention, when the flow of liquid in the heat exchange system stops, the liquid remaining in the heat exchange system stays in the staying part, and even if it freezes, the liquid spreads to the heat exchange means, and the combustion burner An object is to provide a heating device that can operate normally.

  Accordingly, the invention according to claim 1 provided to solve the above-described problem has a combustion burner and a combustion gas passage through which combustion gas generated in the combustion burner flows, and is provided in the middle of the combustion gas passage. Includes a primary heat exchange means capable of heating a liquid by heat exchange with the combustion gas, and a combustion gas disposed downstream of the primary heat exchange means in the flow direction of the combustion gas and having passed through the primary heat exchange means. A secondary heat exchange means for heating the liquid by heat exchange, and a heat exchange system configured by pipe connection of the primary heat exchange means and the secondary heat exchange means, the heat exchange system includes The liquid remaining in the heat exchange system is assumed to stay with the stop of the liquid flow, and the liquid flow direction upstream and downstream with respect to the stay at a position higher than the stay By side, primary heat exchange means Is a heating device, characterized in that the bypass flow passage which can be supplied is provided a liquid secondary heat exchange means.

  In the heating device of the present invention, when the flow of the liquid stops in the heat exchange system, the liquid stays in the staying portion, but even if the staying liquid freezes and the liquid cannot pass through the staying portion, the bypass flow path The liquid flows through the heat exchange system. Therefore, in the heating device of the present invention, once the liquid flow in the heat exchange system is stopped, even if the liquid freezes and the liquid cannot pass through the staying portion, if the liquid is supplied to the heat exchange system again, the bypass flow A liquid flow is generated through the passage, and the combustion burner is operated. Therefore, in the heating device of the present invention, even if the liquid freezes in the staying portion, the malfunction of the combustion burner due to this does not occur.

  In the heating device of the present invention, when the liquid flows through the bypass channel, the liquid flows into the primary heat exchange means or the secondary heat exchange means. For this reason, in the heating device of the present invention, even if the staying part becomes in a state where liquid cannot pass through due to freezing of the liquid, the primary heat exchange means and the secondary heat exchange means do not enter a so-called empty state.

  The invention according to claim 2 provided on the basis of the same knowledge has a combustion burner and a combustion gas passage through which combustion gas generated in the combustion burner flows, and is provided in the middle of the combustion gas passage. Is a primary heat exchange means capable of heating the liquid by heat exchange with the combustion gas, and heat with the combustion gas which is disposed downstream of the primary heat exchange means in the flow direction of the combustion gas and which has passed through the primary heat exchange means. Secondary heat exchange means for heating the liquid by exchange is provided, and the heat exchange system is configured by connecting the primary heat exchange means and the secondary heat exchange means by piping. Supplies the liquid to the primary heat exchange means or the secondary heat exchange means by bypassing the staying part in the middle of the primary heat exchange means and the secondary heat exchange means, and in the state where liquid passage in the staying part is blocked With a possible bypass flow path A heating device for a.

  In the heating device of the present invention, even when the liquid cannot pass through the staying part due to freezing of the liquid or the like, the liquid can flow around the staying part via the bypass channel. For this reason, in the heating device of the present invention, even when the liquid freezes while the liquid flow is stopped in the heat exchange system and the liquid cannot pass through the staying part, the liquid is supplied again to the heat exchange system. Liquid flows through the bypass channel. Therefore, in the heating device of the present invention, even if the liquid staying in the staying portion is frozen, the combustion burner can be operated by supplying the liquid again to the heat exchange system. Therefore, according to the present invention, it is possible to provide a heating device in which the combustion burner can perform a combustion operation regardless of whether or not the liquid is frozen in the staying portion.

  In addition, the heating device of the present invention is configured such that the liquid is distributed to the primary heat exchange means and the secondary heat exchange means even when the liquid is frozen in the staying portion. Therefore, according to the present invention, it is possible to prevent the primary heat exchanging means and the secondary heat exchanging means from being in a so-called empty state even when the staying portion cannot pass through the liquid.

  Here, in the heating device according to claim 1 or 2, in order to ensure that the above-described effects can be reliably exhibited, when the liquid flow (liquid supply) in the heat exchange system is stopped, it remains in the heating passage. It is desirable to adopt a configuration that prevents the liquid to flow into the bypass flow path as much as possible. That is, if the liquid remaining in the heat exchange system enters and stays in the bypass flow path, liquid passing through the bypass flow path cannot be secured, and the above-described malfunction of the combustion burner may not be eliminated.

  Therefore, based on such knowledge, the heating device according to claim 1 or 2 preferably has a configuration in which the bypass channel is inclined toward the downstream side or the upstream side in the liquid flow direction (claim 3). .

  In the heating device of the present invention, since the bypass channel is inclined toward the downstream side or the upstream side in the liquid flow direction, even if the liquid enters the bypass channel, the liquid follows the inclination. It flows into the heat exchange system and does not remain in the bypass channel. Therefore, even if the liquid remains in the heat exchange system and the liquid freezes, the heating device of the present invention generates a liquid flow in the heat exchange system by supplying the liquid again to the heat exchange system, and the combustion burner Combustion operation can be started. Therefore, according to the present invention, even if the liquid freezes in the staying portion, it is possible to provide a heating device in which the combustion burner can immediately start operation if the liquid is supplied to the heat exchange system.

  Further, the invention according to claim 4, which is provided based on the same knowledge as that of the invention according to claim 3, is configured such that the bypass channel has an upward slope from the upstream side to the downstream side in the liquid flow direction. The heating device according to claim 1, wherein the heating device is provided.

  According to such a configuration, it is possible to minimize the intrusion of the liquid into the bypass channel and the freezing of the liquid in the bypass channel. Therefore, according to the present invention, it is possible to provide a heating device in which the combustion burner can immediately start operation when liquid is supplied to the heat exchange system.

  Moreover, as for the heating apparatus in any one of the said Claims 1-4, it is desirable for the flow path resistance of a bypass flow path to be larger than the flow path resistance of a retention part (Claim 5).

  In the case of the above-described configuration, the liquid remaining in the heat exchange system flows preferentially into the staying portion and is difficult to flow into the bypass flow path. For this reason, in the heating device of the present invention, even if the liquid remaining in the heat exchange system freezes, it is unlikely that the bypass channel freezes. Therefore, in the heating device of the present invention, even if the liquid remaining in the heat exchange system freezes, the liquid flows through the bypass channel, and the combustion burner can start the combustion operation. Therefore, according to the present invention, even if the liquid remaining in the heat exchange system freezes, it is possible to provide a heating device that can immediately start the combustion burner by supplying the liquid to the heat exchange system again.

  According to a sixth aspect of the present invention, the combustion burner operates on the condition that a liquid having a predetermined operating flow rate or more flows in the heat exchange system, and the bypass channel passes the liquid having the operating flow rate or higher. It is possible, It is a heating apparatus in any one of Claims 1-5 characterized by the above-mentioned.

  According to such a configuration, even when the staying portion is in a state where liquid cannot be passed at all, by supplying the liquid to the heat exchange system, the liquid flows through the bypass flow path, and the combustion burner can start the combustion operation. A heating device can be provided.

  Here, in the heating device according to any one of claims 1 to 6, when the primary heat exchange means includes a heat receiving pipe through which a liquid flows, the bypass flow path is connected to the primary heat exchange means. The liquid flow direction upstream side and the heat receiving pipe may be bypassed (claim 7).

  Even in the case of such a configuration, even if the liquid remaining in the heat exchange system stays in the retention part and freezes, similarly to the heating device according to claims 1 to 7, the heat exchange system then enters the heat exchange system. By supplying liquid, it is possible to provide a heating device in which the combustion burner can start operation immediately.

  According to the present invention, when the flow of the liquid in the heat exchange system is stopped, even if the liquid remaining in the heat exchange system is frozen, the liquid spreads to the heat exchange means, and the combustion burner can operate normally. Equipment can be provided.

  Subsequently, a heating apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings. In FIG. 1, 1 is a heating apparatus of this embodiment. The heating device 1 is a so-called latent heat recovery type combustion device, and includes a combustion section 2 that burns fuel inside a can body 6 and a combustion gas passage 3 through which combustion gas generated by combustion flows. Yes. A primary heat exchanger 4 is disposed in the middle of the combustion gas flow path 3, and a secondary heat exchanger 5 is disposed downstream of the primary heat exchanger 4 in the combustion gas flow path 3. The combustion unit 2 includes a combustion burner 10 configured by arranging a plurality of combustion tubes 8, an ignition device 9, and a blower 11 for supplying air necessary for combustion to the combustion burner 10. Yes.

  The primary heat exchanger 4 is arranged on the upstream side (combustion burner 10 side) in the combustion gas flow direction in the combustion gas flow path 3, and functions mainly as a sensible heat recovery means for recovering the sensible heat of the combustion gas. It is. The primary heat exchanger 4 is configured by a so-called fin-and-tube heat exchanger. The primary heat exchanger 4 is substantially entirely made of copper and, as shown in FIG. 1 and FIG. 2A, is received so as to cross a large number of fins 4b arranged in parallel inside the cylindrical case 4a. A plurality of heat tubes 4c are attached. The primary heat exchanger 4 has a bent flow path formed by connecting a plurality of heat receiving tubes 4c with bend tubes 4d.

  The primary heat exchanger 4 includes a water inlet 15 and a water outlet 16 communicating with the heat receiving pipe 4c. The water inlet 15 is located on the lower side when the primary heat exchanger 4 is incorporated in the heating device 1. The water inlet 15 is connected to a water outlet 27 of the secondary heat exchanger 5 to be described later via a connection channel 18. Therefore, hot water that has been heat-exchanged in the secondary heat exchanger 5 flows into the primary heat exchanger 4.

  A hot water supply pipe 41 for supplying hot water to the hot water tap 48 is connected to the water outlet 16 of the primary heat exchanger 4. A flow rate sensor 45 (flow rate detection means) for detecting the flow rate of hot water is provided in the middle of the hot water supply pipe 41. The heating device 1 is configured such that the combustion burner 10 starts the combustion operation on condition that the detected flow rate exceeds a predetermined flow rate (minimum operating flow rate W).

  A hot water supply / water supply bypass pipe 43 is connected to the hot water supply pipe 41. The hot water supply / water supply bypass pipe 43 is a pipe branched from the water supply pipe 40 for supplying hot water from an external water supply source, and a bypass flow rate adjusting valve 47 is provided in the middle. The bypass flow rate adjustment valve 47 is feedback-controlled based on the temperature of hot water sent to a load terminal or the like.

  The secondary heat exchanger 5 is a so-called multi-tube type heat in which a large number of heat receiving tubes 24 are brazed and connected between headers 23 and 25 arranged in parallel to both ends of a hollow box-shaped case member 22. It is an exchanger. The secondary heat exchanger 5 has a water inlet 26 and a water outlet 27 on the header 23 side.

  The water inlet 26 is connected to a water supply pipe 40 for supplying hot water from an external water supply source. Further, the water outlet 27 is connected to the water inlet 15 of the primary heat exchanger 4 via the connection flow path 18. In the header 23, the space on the water inlet 26 side and the space on the water outlet 27 side are independent. Therefore, the hot water flowing in from the water inlet 26 flows through the heat receiving pipe 24, crosses the case member 22, and flows into the header 25.

  The hot water that has flowed into the header 25 flows in the header 25 with its flow direction reversed, flows into the header 23 side, flows into the space on the water outlet 27 side of the header 23, and is discharged from the water outlet 27. The secondary heat exchanger 5 collects most of the latent heat of the combustion gas by exchanging heat by flowing hot water as described above.

  The heating device 1 of the present embodiment includes a heat exchange system 30 that heats hot water in the primary heat exchanger 4 and the secondary heat exchanger 5 described above. The heat exchange system 30 is configured such that the primary heat exchanger 4 and the secondary heat exchanger 5 are connected by a connection flow path 18.

  The connection flow path 18 is a flow path that connects the water inlet 15 of the primary heat exchanger 4 and the water outlet 27 of the secondary heat exchanger 5. As shown by hatching in FIG. 1, the connection flow path 18 has a trap structure portion 31 (retention portion) in the middle. The trap structure 31 has a structure that rises from the side of the secondary heat exchanger 5 to below the primary heat exchanger 4 and then rises to the water inlet 15 of the primary heat exchanger 4. In addition, the trap structure 31 is located at a position lower than other parts constituting the heat exchange system 30 in the assembled state to the heating device 1. Therefore, when running water in the heat exchange system 30 stops, the hot water remaining in the heat exchange system 30 collects and stays in the trap structure 31.

  In the trap structure 31, the thickness of the pipe constituting the trap structure 31 is thicker than the thickness of the heat receiving pipe 4 c of the primary heat exchanger 4 and the heat receiving pipe 24 of the secondary heat exchanger 5. Therefore, the trap structure 31 has high strength, and even if the staying hot water is frozen, the pipe is not easily cracked.

  Moreover, the capacity | capacitance of the trap structure part 31 is the secondary heat after draining the hot water which accumulates in the trap structure part 31 through the discharge flow path 32 after performing the draining operation | movement mentioned later after the stop of the flowing water in the heat exchange system 30. It is set larger than the amount of hot water expected to come out of the exchanger 5 or the like. In the present embodiment, the capacity of the trap structure 31 is adjusted to be about 20 to 30 [ml].

  Moreover, as for the piping which comprises the connection flow path 18 connected to the trap structure part 31, the part which falls from the secondary heat exchanger 5 side is bent in substantially "<" shape as shown in FIG.2 (b), The pipes constituting the trap structure 31 are substantially orthogonal to the piping. Therefore, even if hot water flows into the bypass flow path 35, the hot water flows down smoothly when there is no water flow in the bypass flow path 35. Further, the pipe connecting the trap structure 31 and the primary heat exchanger 4 is also bent in a substantially “<” shape and is substantially orthogonal to the pipe constituting the trap structure 31. Therefore, the hot water that bypasses the bypass flow path 35 smoothly flows into the primary heat exchanger 4 side.

  As shown in FIG. 2, the pipes constituting the trap structure 31 are arranged so that substantially the whole is along the outer peripheral surface 6 a of the can body 6 located below the primary heat exchanger 4. Therefore, when the combustion burner 10 performs a combustion operation, the piping constituting the trap structure 31 is substantially entirely heated by receiving heat transfer from the can body 6.

  A discharge flow path 32 is connected to the trap structure 31. The discharge flow path 32 is a flow path for discharging hot water remaining when water flow is stopped in the connection flow path 18, and the trap structure portion is opened by opening a discharge valve 33 provided in the middle of the discharge flow path 32. The hot water accumulated in 31 can be discharged.

  The connection flow path 18 has a bypass flow path 35 that bypasses the upstream side and the downstream side in the hot water flow direction with respect to the trap structure 31. Further, the bypass channel 35 is located above the trap structure 31. Therefore, the bypass flow path 35 has a structure that allows water to bypass the trap structure 31 in a state where hot water flows in the trap structure 31 and the flow of hot water in the trap structure 31 is blocked. It has become.

  As shown in FIG. 1, the bypass channel 35 has a connection portion C <b> 1 between the end of the downstream side of the hot water flowing from the secondary heat exchanger 5 side and the connection channel 18 in the upstream of the hot water flow direction. It connects so that it may be located above the connection part C2 of the edge part of a side and the connection flow path 18. FIG. That is, the bypass flow path 35 is in a state in which an upward gradient is given from the downstream side in the flow direction of the hot water flowing through the connection flow path 18 toward the upstream side. Therefore, even if hot water is dripped from the secondary heat exchanger 5 side to the trap structure 31 side via the connection flow path 18, the hot water does not enter the bypass flow path 35.

  The opening diameter d1 of the bypass channel 35 is set to a size that allows hot water having a flow rate equal to or higher than the above-described minimum operating flow rate W to pass. Further, the opening diameter d1 of the bypass flow path 35 is smaller than the opening diameter d2 of the connection flow path 18. More specifically, the opening diameter d1 of the bypass channel 35 is in a range of about 1/3 to 2/3 of the opening diameter d2 of the connection channel 18. In the present embodiment, the opening diameter d1 is about ½ of the opening diameter d2. Therefore, the bypass channel 35 has a larger channel resistance than the trap structure 31. Therefore, in the heating device 1 of the present embodiment, the hot water flowing into the connection flow path 18 preferentially flows to the trap structure 31 side, and the hot water does not easily flow to the bypass flow path 35 side.

  Then, operation | movement of the heating apparatus 1 of this embodiment is demonstrated. In the heating device 1 of the present embodiment, when the hot water tap 48 is opened, hot water is supplied from the external water source to the secondary heat exchanger 5 through the water supply pipe 40. Along with this, hot water sequentially flows through the heat exchange system 30 constituted by the primary heat exchanger 4, the secondary heat exchanger 5, and the connection flow path 18 and the hot water supply pipe 41 connected thereto. More specifically, when hot water flows in from the water inlet 26 of the secondary heat exchanger 5, hot water flows into each heat receiving pipe 24 arranged between the headers 23, 25, and the secondary heat exchanger 5 from the water outlet 27. Go outside. Hot water discharged from the water outlet 27 passes through the connection flow path 18 and flows into the heat receiving pipe 4 c from the water inlet 15 of the primary heat exchanger 4. Hot water flowing through the heat receiving pipe 4 c is taken out of the primary heat exchanger 4 from the water outlet 16 and supplied to the hot water tap 48 through the hot water supply pipe 41.

  As described above, after the hot water tap 48 is opened, if the flow rate sensor 45 detects a flow of hot water exceeding a predetermined amount in the hot water supply pipe 41, a combustion operation is started in the combustion burner 10. When the combustion burner 10 starts a combustion operation, the high-temperature combustion gas generated along with this flows through the combustion gas flow path 3 upward.

  The combustion gas flowing through the combustion gas passage 3 exchanges heat with hot water flowing through the heat receiving pipe 4c when passing through the primary heat exchanger 4, and most of the sensible heat is recovered. The combustion gas that has passed through the primary heat exchanger 4 flows into the case member 22 of the secondary heat exchanger 5 that is disposed in the combustion gas flow path 3 on the downstream side in the flow direction of the combustion gas, that is, on the upper side. The combustion gas that has flowed into the case member 22 exchanges heat with hot water flowing in each heat receiving pipe 24. Thereby, in addition to the sensible heat remaining in the combustion gas, most of the latent heat of the combustion gas is recovered. The combustion gas is discharged outside the heating device 1 after the latent heat is recovered in the secondary heat exchanger 5.

  On the other hand, when the hot-water tap 48 is closed, the above-described hot water flow stops. Accordingly, in addition to the water supply pipe 40, the hot water supply pipe 41, and the hot water supply / water supply bypass pipe 43, the heat exchange system 30 in which the primary heat exchanger 4 and the secondary heat exchanger 5 are connected by the connection flow path 18 is also provided. Hot water will remain.

  Here, when the temperature is high or when the hot water tap 48 is assumed to be opened again within a short period of time after the hot water tap 48 is closed, hot water remains in the heat exchange system 30 or the like. If so, this is unlikely to cause freezing. However, when the possibility that the temperature of the hot water is frozen is low to some extent or when the hot water tap 48 is kept closed for a long time after the hot water tap 48 is closed, the heat exchange system 30. The hot water remaining in the water may freeze, and the primary heat exchanger 4 and the secondary heat exchanger 5 may be damaged. Therefore, when such a situation is assumed, the heating device 1 opens the discharge valve 33 of the discharge flow path 32 connected to the trap structure 31 to thereby form the primary heat exchanger 4 and the secondary heat exchanger. 5 is configured such that a water draining operation for discharging hot water remaining in 5 can be performed to prevent freezing.

  As described above, the heating device 1 is configured to be capable of discharging hot water remaining in the connection flow path 18 by performing a water draining operation. However, due to the structural reasons of the primary heat exchanger 4 and the secondary heat exchanger 5 employed in the heating device 1, hot water remaining in the heat exchange system 30 or the like cannot be completely removed at the time of draining operation. , May remain. Therefore, in the heating device 1, the hot water remaining in the primary heat exchanger 4 and the secondary heat exchanger 5 gathers in the trap structure 31 and accumulates after the discharge valve 33 is closed with the completion of the water draining operation. May end up.

  As described above, when hot water accumulates in the trap structure 31 and freezes, the hot water tap 48 is opened again, and even if hot water flows into the connection flow path 18 from the secondary heat exchanger 5 side, It cannot pass through the trap structure 31. That is, when the hot water is frozen in the trap structure 31, the water flow in the trap structure 31 is blocked. Therefore, when the hot water tap 48 is opened while the hot water is frozen in the trap structure 31, the hot water that has flowed into the connection channel 18 bypasses the trap structure 31 and is primarily heated via the bypass channel 35. It flows into the exchanger 4 side.

  As described above, the opening diameter d1 of the bypass channel 35 is set to a size that allows hot water having a minimum operating flow rate W to pass through. Therefore, even if the trap structure portion 31 is not allowed to pass through due to freezing of hot water, hot water with a minimum operating flow rate W or more passes through the bypass channel 35 by opening the hot water tap 48. Hot water flows into the primary heat exchanger 4 and the hot water supply pipe 41, and the combustion burner 10 can resume the combustion operation.

  When the combustion operation is started in the combustion burner 10 as described above, the heat energy generated thereby is transmitted to the pipe of the trap structure portion 31 arranged at a position adjacent to the can body 6. Thereby, the hot and cold water frozen in the trap structure 31 gradually melts, and the hot water flows into the trap structure 31.

  As described above, in the heating device 1 of the present embodiment, the trap structure 31 is provided in the middle of the connection flow path 18, and the secondary heat exchanger 5 that constitutes the heat exchange system 30 during the water draining operation. The hot water remaining without being removed from the trap structure 31 is collected in the trap structure 31. Since the pipes constituting the trap structure 31 do not need to consider heat transfer characteristics like the heat receiving pipes 4c and 24 constituting the primary heat exchanger 4 and the secondary heat exchanger 5, these heat receiving pipes 4c, It is thicker than 24 and high in strength. Therefore, even if hot water accumulates in the trap structure 31 and freezes after the draining operation, the heating device 1 does not cause damage to the heat exchange system 30.

  Moreover, since the heating apparatus 1 has a configuration in which the bypass flow path 35 is provided above the trap structure 31, hot water remaining in the trap structure 31 after the draining operation is frozen, and the trap structure Even in a state where hot water cannot pass through 31, hot water supplied via the connection flow path 18 can be sent to the primary heat exchanger 4 side via the bypass flow path 35. The bypass passage 35 is configured to allow hot water to flow at a flow rate equal to or higher than the minimum operation flow rate W, which is an operation condition of the combustion burner 10. Therefore, in the heating device 1, even when the trap structure 31 is in a frozen state, the combustion burner 10 can immediately start the combustion operation by opening the hot water tap 48. That is, in the heating device 1, the water flow failure due to the freezing of the trap structure 31 and the operation failure of the combustion burner 10 due to this do not occur.

  In the heating apparatus 1, the bypass channel 35 is located at a position where the connection portion C1 on the downstream side in the flowing direction of hot water is higher than the connection portion C2 on the upstream side in the flowing direction of hot water. That is, the bypass flow path 35 is a flow path with an upward slope from the upstream side to the downstream side in the hot water flow direction. Therefore, according to the above-described configuration, hot water flowing from the secondary heat exchanger 5 side hardly enters the bypass flow path 35. Therefore, the heating device 1 is less likely to cause problems such as hot water remaining in the bypass channel 35 or freezing of the bypass channel 35.

  In the above embodiment, since there is a high possibility that hot water remains in the secondary heat exchanger 5 during the draining operation, the hot water flow direction downstream side of the bypass passage 35 (secondary heat exchanger 5 side). The connecting portion C1 is inclined so as to be higher than the connecting portion C2 on the upstream side (secondary heat exchanger 5 side) in the hot water flow direction, but the present invention is not limited to this. . More specifically, for example, when it is assumed that there is a high possibility that hot water remains on the primary heat exchanger 4 side during the water draining operation, the inclination of the bypass flow path 35 is reversed and the connection portion C1 side is You may make it become lower than the connection part C2 side. In order to prevent hot water from entering or remaining in the bypass channel 35, it is desirable to incline the bypass channel 35, but the bypass channel 35 may be configured not to incline.

  The opening diameter d1 of the bypass channel 35 is desirably smaller than the opening diameter d2 of the trap structure 31 as described above, but the present invention is not limited to this. The opening diameter d1 may be equal to the opening diameter d2 or larger than the opening diameter d2.

  Further, the bypass flow path 35 has a passage resistance larger than that of the trap structure portion 31 by making the opening diameter d1 of the pipe smaller than the opening diameter d2 of the trap structure portion 31. It is not limited, For example, you may make it the structure which diameter-reduced only the one side or both ends of the connection parts C1 and C2.

  In the heating device 1, even when the hot water is frozen in the trap structure 31, the hot water flows through the bypass channel 35, and the liquid reaches the primary heat exchanger 4. For this reason, in the heating device 1, the primary heat exchanger 4 is not in a so-called empty state even when the trap structure 31 is in a state in which liquid passage is impossible.

  In the said embodiment, piping which comprises the trap structure part 31 is distribute | arranged so that the outer peripheral surface 6a of the can body 6 may be followed, and it becomes the structure heated by the heat transfer from the can body 6. FIG. Therefore, even when the trap structure 31 is frozen, the heating device 1 causes the hot water to flow through the bypass channel 35 and the combustion burner 10 starts to operate. The frozen state of the trap structure 31 is released due to the influence of heat. Therefore, even if the trap structure 31 is frozen, the heating apparatus 1 returns to a normal water flow state in which hot water passes through the trap structure 31 soon after the operation of the combustion burner 10 starts.

  In the above embodiment, the trap structure 31 has a substantially “U” shape as shown in FIG. 1 and the like. However, the present invention is not limited to this, and a substantially “S” shape or the like. Any suitable shape can be obtained. That is, the trap structure 31 may have a shape that retains the hot water remaining in the heat exchange system 30 when the flow of the hot water in the heat exchange system 30 stops.

  Moreover, although the heating apparatus 1 of the said embodiment was the structure which provided the trap structure part 31 in the middle of the connection flow path 18 which comprises the heat exchange system | strain 30, this invention is not limited to this, For example, it is good also as a structure which does not provide the trap structure part 31 like the heating apparatus 50 shown in FIG. In the case of such a configuration, when water draining operation is performed after water flow in the heat exchange system 30 is stopped, the heat receiving pipe 4c constituting the primary heat exchanger 4 is positioned below as shown by hatching in FIG. In the heat receiving pipe 4c, the hot water that has not been removed from the heat exchanging system 30 during the water draining operation stays. That is, in the heating device 50, hot water stays in a portion (retaining portion 51) indicated by hatching in FIG. 3 in the same manner as the trap structure portion 31 described above.

  When it is set as the structure which does not provide the trap structure part 31 like the heating apparatus 50, if it is set as the structure which provided the bypass flow path 35 above the heat receiving pipe 4c which comprises the retention part 51, as shown in FIG. The same operational effects as those of the heating device 1 described above can be exhibited. More specifically, in the heating device 50, a portion of the connection flow path 18 on the upstream side in the hot water flow direction from the staying portion 51, and the heat receiving tube 4 c positioned above the heat receiving tube 4 c constituting the staying portion 51. May be connected by the bypass channel 35 and communicated with each other. In such a configuration, even if hot water remaining on the bottom side of the primary heat exchanger 4 is frozen after the water draining operation, the hot water supplied by opening the hot water tap 48 again is primary through the bypass channel 35. It can pass through the heat exchanger 4. Therefore, even if it is configured as the heating device 50, the hot water supply operation is immediately resumed even when the hot water staying in the staying part 51 is frozen after the water draining operation as in the heating device 1. be able to.

  Moreover, even if the hot water is frozen in the retention part 51 comprised by the one part heat receiving pipe 4c which comprises the primary heat exchanger 4, the heating apparatus 50 provides the bypass flow path 35 to the remaining heat receiving pipe 4c. It is set as the structure into which hot water flows through. Here, since the heat receiving pipe 4c constituting the staying portion 51 is frozen by remaining hot water, when the combustion burner 10 is actuated and exposed to high-temperature combustion gas, the hot water immediately frozen is exposed. Because it melts, it does not go into the sky Further, the remaining heat receiving pipe 4c does not become empty because hot water supplied through the bypass passage 35 flows when the combustion burner 10 is operated. Accordingly, even in the case of the configuration of the heating device 50, even if the combustion burner is operated in a state where the hot water is frozen in the staying portion 51, it will not be in an empty state.

  When the staying part 51 is formed in a part of the primary heat exchanger 4 as in the heating device 50, when a large amount of hot water flows into the heat receiving pipe 4c constituting the staying part 51 to cause freezing, the heat receiving pipe 4c May be damaged. However, in the heating device 50, the entire heat receiving pipe 4 c arranged so as to cross the bottom side of the primary heat exchanger 4 functions as the staying portion 51, so that the volume of the staying portion 51 is relatively large. Therefore, even when it is configured as the heating device 50, the primary heat exchanger 4 is not easily damaged due to freezing of hot water collected in the staying part 51 after the draining operation.

  The heating devices 1 and 50 described above are for heating hot water supplied to the hot water tap 48, respectively, but the present invention is not limited to this. For example, hot water for dropping into a bath, a heating terminal, etc. It is good also as a structure which heats the hot water and heat medium supplied with respect to this load terminal.

  The heating devices 1 and 50 described above are so-called one-can-one-water heating devices that heat hot water used for a single heat load (hot water supply). However, the present invention is not limited to this, for example, a heating system for heating hot water for hot water supply having a configuration similar to the above-described configuration, and a heating system for heating hot water for dropping into a bath May be applied to a so-called single-can two-water heating device or the like arranged in a single can body.

  Each of the heating devices 1 and 50 described above has a configuration in which the combustion burner 10 is disposed below the primary heat exchanger 4 and the secondary heat exchanger 5, but the present invention is not limited to this. The so-called reverse combustion type combustion mode in which a combustion burner 10 is disposed above the primary heat exchanger 4 and the secondary heat exchanger 5 to form a flame from the upper side to the lower side may be adopted. .

  Further, when the above-described reverse combustion type combustion mode is adopted, the upper and lower positional relationship between the primary heat exchanger 4 and the secondary heat exchanger 5 with respect to the heating devices 1 and 50 from the viewpoint of heat energy recovery efficiency. It is desirable to replace That is, when the reverse combustion type combustion mode is adopted, the combustion gas flows from the upper side to the lower side. Therefore, in order to optimize the heat exchange efficiency, the primary heat exchanger 4 is moved upward (the direction of the combustion gas flow). It is desirable that the secondary heat exchanger 5 be arranged on the lower side (downstream in the flow direction of the combustion gas).

  When the positional relationship between the primary heat exchanger 4 and the secondary heat exchanger 5 is exchanged as described above, as in the heating device 1, the secondary heat exchanger 5 is disposed below the connection flow path 18. By providing the trap structure 31 that falls to the position on the lower side, and by providing a bypass flow path 35 above this, even if the hot water staying in the trap structure 31 after freezing operation is frozen, A heating device that can immediately resume hot water supply operation can be provided.

  Moreover, when it is set as the structure which distribute | arranged the primary heat exchanger 4 above the secondary heat exchanger 5 as mentioned above, the secondary arrange | positioned below in the middle of the connection flow path 18 like the heating apparatus 50. Of the heat receiving pipe 24 of the heat exchanger 5, a bypass pipe 35 is provided that bypasses the heat receiving pipe 24 that is located above a portion (a staying portion) that is arranged in a portion where the hot water is expected to stay after the drain operation. Even with this configuration, it is possible to eliminate the malfunction of the combustion burner 10 due to freezing of hot water remaining in the staying portion after the water draining operation.

  In the said embodiment, although the fin and tube type heat exchanger was employ | adopted as the primary heat exchanger 4, and the example which employ | adopted the multi-tube type heat exchanger as the secondary heat exchanger 5 was illustrated, the said structure Is merely an embodiment of the present invention, and may be configured to include other types of heat exchangers, such as a so-called plate fin type heat exchanger.

It is an operation | movement principle figure which shows the heating apparatus which is one Embodiment of this invention. (A) It is a top view which shows the structure of the primary heat exchanger and trap structure part which are employ | adopted in the heating apparatus shown in FIG. 1, (b) is an A direction arrow directional view of (a), (c) is ( FIG. 4A is a view in the direction of arrow B in FIG. 4A, and FIG. It is an operation principle figure which shows the modification of the heating apparatus shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,50 Heating apparatus 3 Combustion gas flow path 4 Primary heat exchanger 4c Heat receiving pipe 5 Secondary heat exchanger 10 Combustion burner 24 Heat receiving pipe 30 Heat exchange system 31 Trap structure part (stagnation part)
35 Bypass channel 45 Flow rate sensor (Flow rate detection means)
51 Staying part

Claims (7)

A combustion burner and a combustion gas passage through which combustion gas generated in the combustion burner flows;
In the middle of the combustion gas flow path, a primary heat exchange means capable of heating the liquid by heat exchange with the combustion gas, and a primary heat exchange means disposed downstream of the primary heat exchange means in the flow direction of the combustion gas. Secondary heat exchange means for heating the liquid by heat exchange with the combustion gas that has passed through, and a heat exchange system configured by connecting the primary heat exchange means and the secondary heat exchange means by piping. ,
In the heat exchange system, the liquid remaining in the heat exchange system is assumed to stay with the stop of the liquid flow,
A bypass flow path is provided that bypasses the upstream and downstream sides in the liquid flow direction with respect to the staying portion at a position higher than the staying portion, and can supply liquid to the primary heat exchange means or the secondary heat exchange means. A heating device characterized by that. A combustion burner and a combustion gas passage through which combustion gas generated in the combustion burner flows;
In the middle of the combustion gas flow path, a primary heat exchange means capable of heating the liquid by heat exchange with the combustion gas, and a primary heat exchange means disposed downstream of the primary heat exchange means in the flow direction of the combustion gas. Secondary heat exchange means for heating the liquid by heat exchange with the combustion gas that has passed through,
A heat exchange system is configured by connecting the primary heat exchange means and the secondary heat exchange means by piping,
The heat exchange system includes a staying part in the middle of the primary heat exchanging means and the secondary heat exchanging means, and bypassing the staying part in a state where liquid passage in the staying part is blocked, the primary heat exchanging means or the secondary heat exchanging means And a bypass channel capable of supplying a liquid to the heating device.   The heating apparatus according to claim 1, wherein the bypass channel is inclined toward the downstream side or the upstream side in the liquid flow direction.   The heating apparatus according to claim 1 or 2, wherein the bypass channel is provided with an upward gradient from the upstream side toward the downstream side in the liquid flow direction.   The heating apparatus according to claim 1, wherein a flow path resistance of the bypass flow path is larger than a flow path resistance of the staying portion. The combustion burner operates on the condition that liquid of a predetermined operating flow rate or more flows in the heat exchange system,
The heating device according to any one of claims 1 to 5, wherein the bypass channel is capable of passing a liquid having a flow rate equal to or higher than the operating flow rate. The primary heat exchange means includes a heat receiving pipe through which a liquid flows,
The heating apparatus according to any one of claims 1 to 6, wherein the bypass flow path bypasses the upstream side in the liquid flow direction and the heat receiving pipe with respect to the primary heat exchange means.

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