Water heater

Abstract

To suppress erosion of pipes constituting a hot water outlet passage.SOLUTION: A water heater 1 comprises a bypass pipe 30 that short-circuits a water inlet passage 10 and a hot water outlet passage 20. The bypass pipe 30 comprises a bypass pipe body 31, and a flow rate regulation pipe 32 that connects the bypass pipe body 31 and the hot water outlet passage 20 and regulates a water flow rate. The flow rate regulation pipe 32 comprises a small-diameter part 33 that has a smaller diameter than the bypass pipe body 31, and a large-diameter part 34 that is connected to the downstream side of the small-diameter part 33 and has a larger diameter than the small-diameter part 33.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to water heaters. [Background technology]

[0002] A water heater described in Japanese Patent No. 3990845 (Patent Document 1 below) is known. The water heater described in Patent Document 1 includes a heat exchanger that heats water supplied from a water supply line and sends it to a hot water outlet line, and a bypass line that bypasses the heat exchanger and connects the water supply line and the hot water outlet line. In this water heater, the flow rate of the bypass line is not controlled by a proportional valve or the like, and the bypass ratio, which is the ratio of the water supplied to the heat exchanger to the water flowing through the bypass line, is constant.

[0003] In a water heater with a constant bypass ratio as described above, an orifice that determines the bypass ratio is provided in the bypass passage. The orifice is a portion of the bypass passage that has a smaller diameter than the rest of the bypass passage. Specifically, the bypass ratio is determined by appropriately setting the diameter of the orifice. The orifice is located, for example, at the end of the bypass passage on the outlet passage side (downstream side). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 3990845 Summary of the Invention [Problem to be solved by the invention]

[0005] When an orifice is provided at the downstream end of the bypass passage as described above, the water increases in flow velocity as it passes through the orifice and then flows into the tap passage without losing its momentum, which can cause erosion of the wall of the tap passage facing the bypass passage. [Means for solving the problem]

[0006] The water heater of the present disclosure is a water heater equipped with a bypass pipe that short-circuits a water inlet passage and a hot water outlet passage, the bypass pipe comprising a bypass pipe main body and a flow rate regulating pipe that connects the bypass pipe main body to the hot water outlet passage and regulates the water flow rate, the flow rate regulating pipe comprising a small diameter section that is smaller in diameter than the bypass pipe main body, and a large diameter section that is connected downstream of the small diameter section and has a diameter larger than the small diameter section. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to suppress erosion of the piping that constitutes the melt discharge passage. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram illustrating a water heater according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view showing the connection between the outlet channel and the bypass pipe. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Description of the embodiments of the present disclosure] First, embodiments of the present disclosure will be listed and described.

[0010] (1) The water heater of the present disclosure is a water heater equipped with a bypass pipe that short-circuits a water inlet passage and a hot water outlet passage, the bypass pipe comprising a bypass pipe body and a flow rate regulating pipe that connects the bypass pipe body and the hot water outlet passage and regulates the water flow rate, the flow rate regulating pipe comprising a small diameter section that is smaller in diameter than the bypass pipe body, and a large diameter section that is connected downstream of the small diameter section and has a larger diameter than the small diameter section.

[0011] With this configuration, the bypass ratio can be controlled by the small diameter section, while the flow velocity can be reduced in the large diameter section downstream of the small diameter section. As a result, when the water flows from the bypass pipe into the melt discharge passage, the force with which the water collides with the pipes that make up the melt discharge passage can be weakened, and erosion of the pipes that make up the melt discharge passage can be suppressed.

[0012] (2) In the water heater described in (1), it is preferable that the large diameter portion is longer than the small diameter portion in the direction of water flow.

[0013] With this configuration, the effect of reducing the flow velocity in the large diameter portion can be further enhanced, and erosion of the piping that constitutes the melt discharge passage can be further suppressed.

[0014] (3) In the water heater described in (1) or (2), it is preferable that the flow rate regulating pipe further comprises a reduced diameter section arranged at the upstream end of the flow rate regulating pipe, the diameter of the reduced diameter section gradually decreases from the upstream side to the downstream side, and the downstream end of the reduced diameter section is connected to the upstream end of the small diameter section.

[0015] This configuration can suppress the occurrence of cavitation in the small diameter portion, thereby suppressing damage to the flow rate regulating pipe and the pipes that form the melt discharge path due to cavitation occurring in the small diameter portion.

[0016] [Details of the embodiments of the present disclosure] Embodiments of the present disclosure will be described with reference to Figures 1 and 2. The present disclosure is not limited to these examples, but is defined by the scope of the claims, and is intended to include all modifications within the meaning and scope of the claims.

[0017] [Overall structure of the hot water heater] The water heater 1 of this embodiment has a hot water supply function of heating supplied tap water and supplying hot water to the outside. As shown in FIG. 1, the water heater 1 is configured with a water inlet passage 10, a hot water outlet passage 20, a bypass pipe 30, a heat exchanger 40, a burner 50, a controller 60, etc. The water inlet passage 10 is a path for supplying tap water. The hot water outlet passage 20 is a path for supplying hot water to the outside. The bypass pipe 30 directly connects the water inlet passage 10 and the hot water outlet passage 20 so as to bypass the heat exchanger 40. The water inlet passage 10 has a branching portion 10A where the bypass pipe 30 branches off. The hot water outlet passage 20 has a junction portion 20A where the bypass pipe 30 joins. The controller 60 controls combustion by the burner 50, etc.

[0018] In the water heater 1, the bypass ratio, which is the ratio of the water supplied from the water inlet passage 10 to the heat exchanger 40 side to the water flowing from the water inlet passage 10 through the bypass pipe 30 to the hot water outlet passage 20, is constant. This bypass ratio is set by the dimensions of the bypass pipe 30 and a flow rate regulation unit 32 provided in the bypass pipe 30.

[0019] Provided upstream of branch point 10A of inlet water passage 10 are inlet water temperature sensor 11, which detects the inlet water temperature, water governor 12, which limits the maximum inlet water flow rate, and flow rate sensor 13, which detects the inlet water flow rate. Also, provided upstream of junction 20A of hot water outlet passage 20 is inner body temperature sensor 21, which detects the hot water temperature at the outlet side of heat exchanger 40. Provided downstream of junction 20A of hot water outlet passage 20 is outlet hot water temperature sensor 22, which detects the temperature of the hot water at the outlet after it has been mixed with water from bypass pipe 30.

[0020] A gas supply path 70 for supplying gas is connected to the burner 50. The gas supply path 70 is provided with, for example, a main solenoid valve 71 and a base solenoid valve 72 for opening and closing the flow path, and a proportional valve 73 for adjusting the amount of gas supplied.

[0021] The controller 60 is composed of a microcomputer or the like equipped with a CPU, ROM, RAM, I / O, etc. The inlet water temperature sensor 11, flow rate sensor 13, inner body temperature sensor 21, and outlet hot water temperature sensor 22 are connected to the input side of the controller 60. The main solenoid valve 71, master solenoid valve 72, and proportional valve 73 are connected to the output side of the controller 60. The controller 60 is also connected to a remote control 61. The remote control 61 is equipped with an operation unit for setting the set temperature, which is the target value for the temperature of the hot water coming out of the hot water outlet path 20, a display unit for displaying the set temperature, etc.

[0022] The controller 60 adjusts the amount of gas supplied to the burner 50 based on, for example, the water temperature detected by the above-mentioned multiple water temperature sensors 11, 21, 22, the water flow rate detected by the flow rate sensor 13, the set temperature set by the remote control 61, etc., and performs control to bring the temperature of the hot water coming out of the hot water outlet path 20 closer to the set temperature.

[0023] 2 is a cross-sectional view showing the vicinity of the connection portion (junction portion 20A in FIG. 1) between the hot water outlet passage 20 and the bypass pipe 30, and shows a cross section generally along the direction of water flow. In FIG. 2, the first pipe 23 extends vertically in the figure and constitutes part of the hot water outlet passage 20. An insertion hole 23A is formed in the first pipe 23, through which the downstream end of the bypass pipe 30 is inserted. The hole edge of the insertion hole 23A serves as a first connection portion 23B that is connected to the bypass pipe 30. The portion of the first pipe 23 that faces the downstream end of the bypass pipe 30 serves as an opposing wall portion 23C. The opposing wall portion 23C is a portion that receives water flowing in from the bypass pipe 30.

[0024] [Bypass pipe] 2, the bypass pipe 30 includes a bypass pipe main body 31 and a flow rate regulating pipe 32 that connects the bypass pipe main body 31 and the melt discharge passage 20 (first pipe 23). A second connection portion 31A that is connected to the flow rate regulating pipe 32 is provided at the downstream end of the bypass pipe main body 31. The bypass pipe main body 31 has a straight portion 31B that continues to the upstream side of the second connection portion 31A. The straight portion 31B extends, for example, in a direction (left-right direction in the figure) that is substantially perpendicular to the direction in which the first pipe 23 extends (up-down direction in the figure). The bypass pipe main body 31 may be provided with a bent portion 31C having a bent shape on the upstream side of the straight portion 31B.

[0025] [Flow rate regulation pipe] The flow rate regulating pipe 32 has a cylindrical shape as a whole. The flow rate regulating pipe 32 is made of, for example, metal. More specifically, the flow rate regulating pipe 32 in this embodiment is made of brass. The flow rate regulating pipe 32 is disposed at the downstream end of the bypass pipe 30. The flow rate regulating pipe 32 is connected to the downstream end of the bypass pipe main body 31.

[0026] In this embodiment, the flow rate regulating pipe 32 is disposed at the downstream end of the bypass pipe 30, which facilitates the work of connecting the pipes together. For example, unlike this embodiment, if the flow rate regulating pipe were disposed midway along the bypass pipe, two connections would be required between the flow rate regulating pipe and the bypass pipe main body and one connection between the bypass pipe main body and the hot water outlet passage. However, according to this embodiment, there is only one connection between the flow rate regulating pipe 32 and the bypass pipe main body 31 and one connection between the flow rate regulating pipe 32 and the hot water outlet passage 20 (first pipe 23). This reduces the number of pipe connections by one compared to when the flow rate regulating pipe is disposed midway along the bypass pipe. Furthermore, while the bypass pipe 30 is typically disposed inside the water heater 1 while bending to avoid other components, in this embodiment, the flow rate regulating pipe 32 is disposed at the downstream end of the bypass pipe 30, which makes it easier to ensure the space required to connect the flow rate regulating pipe 32 to other pipes (the bypass pipe main body 31 or the first pipe 23).

[0027] Hereinafter, the direction in which the flow rate regulating pipe 32 extends is defined as the axial direction, and the direction perpendicular to the axial direction is defined as the radial direction. Furthermore, the radially outer side refers to the direction away from the center of the flow rate regulating pipe 32 in the radial direction, and the radially inner side refers to the direction approaching the center of the flow rate regulating pipe 32 in the radial direction. In Figure 2, the axial direction is the left-right direction in the figure.

[0028] The flow rate regulating pipe 32 includes a first end 32A, a second end 32B, and a main body 32C disposed between the first end 32A and the second end 32B. The first end 32A is the end on the downstream side (the melt discharge passage 20 side) of the flow rate regulating pipe 32. The second end 32B is the end on the upstream side (the bypass pipe main body 31 side) of the flow rate regulating pipe 32. The outer peripheral surface of the main body 32C is disposed radially outward compared to the outer peripheral surfaces of the first end 32A and the second end 32B. In other words, the outer diameter of the main body 32C is larger than the outer diameters of the first end 32A and the second end 32B. The first end 32A is inserted into the insertion hole 23A of the first pipe 23. The outer peripheral surface of the first end 32A and the stepped portion between the first end 32A and the main body 32C are connected to the first connection part 23B of the first pipe 23 by, for example, brazing. The second end 32B is housed inside the second connecting portion 31A of the bypass pipe main body 31. The outer peripheral surface of the second end 32B and the step portion between the second end 32B and the main body portion 32C are connected to the inner peripheral surface and end face of the second connecting portion 31A, respectively, by, for example, brazing.

[0029] The flow rate regulating pipe 32 is a member for regulating the flow rate of water flowing into the hot water outlet passage 20 via the bypass pipe 30, and has an inner diameter smaller than the inner diameter D1 of the bypass pipe main body 31. The flow rate regulating pipe 32 includes a small diameter section 33 and a large diameter section 34 connected to the downstream side of the small diameter section 33. The inner diameter D2 of the small diameter section 33 and the inner diameter D3 of the large diameter section 34 are smaller than the inner diameter D1 of the bypass pipe main body 31. The inner diameter D3 of the large diameter section 34 is larger than the inner diameter D2 of the small diameter section 33. The small diameter section 33 and the large diameter section 34 are integrally formed. The large diameter section 34 includes the downstream end of the flow rate regulating pipe 32.

[0030] By providing the small diameter portion 33 and reducing the cross-sectional area of the flow rate regulating pipe 32 perpendicular to the direction of water flow (the thick arrow in FIG. 2, the left-right direction in the figure), it is possible to control the amount of water flowing through the bypass pipe 30. The bypass ratio can be determined mainly by the small diameter portion 33.

[0031] By providing the large diameter portion 34 downstream of the small diameter portion 33 and having an inner diameter D3 larger than that of the small diameter portion 33, it is possible to reduce the flow velocity of the water when it flows from the flow rate regulating pipe 32 into the hot water outlet passage 20. Therefore, the force with which the water collides with the opposing wall portion 23C of the first pipe 23 is weakened, and erosion of the first pipe 23 can be suppressed.

[0032] Furthermore, in this embodiment, the large diameter portion 34 is longer than the small diameter portion 33 in the direction in which water flows inside the flow rate regulating pipe 32. Specifically, the length of the large diameter portion 34 in the direction in which water flows is about 5 to 6 times the length of the small diameter portion 33 in the direction in which water flows. This makes it possible to further reduce the flow velocity of water in the large diameter portion 34. Therefore, erosion of the first piping 23 can be further suppressed.

[0033] The flow rate regulating pipe 32 may include a reduced diameter section 35 provided upstream of the small diameter section 33. The reduced diameter section 35 is provided to include the upstream end of the flow rate regulating pipe 32. The inner circumferential surface of the reduced diameter section 35 is inclined with respect to the direction of water flow. The reduced diameter section 35 is configured so that the inner diameter gradually decreases from the upstream end of the flow rate regulating pipe 32 toward the downstream side. The inner circumferential surface of the reduced diameter section 35 is smoothly connected to the inner circumferential surface of the small diameter section 33. The inner diameter of the reduced diameter section 35 at the downstream end is the same as the inner diameter D2 of the small diameter section 33. The reduced diameter section 35 is shorter than the small diameter section 33 in the direction of water flow.

[0034] In this way, by providing the reduced diameter section 35 and gradually reducing the inner diameter from the upstream end of the flow rate regulating pipe 32 to the small diameter section 33, it is possible to alleviate the water pressure difference when water flows from the bypass pipe main body 31 into the flow rate regulating pipe 32 and to suppress the occurrence of cavitation in the small diameter section 33. This makes it possible to suppress damage to the flow rate regulating pipe 32 and the first piping 23 due to cavitation occurring in the small diameter section 33.

[0035] In the flow rate regulating pipe 32, the small diameter section 33 and the large diameter section 34 may be connected via an expanded diameter section 36. The inner circumferential surface of the expanded diameter section 36 is inclined with respect to the direction of water flow. The expanded diameter section 36 is configured so that the inner diameter gradually increases from the upstream side (the small diameter section 33 side) to the downstream side (the large diameter section 34 side). The inner circumferential surface of the expanded diameter section 36 is smoothly connected to the inner circumferential surface of the small diameter section 33. The inner diameter of the expanded diameter section 36 at the upstream end is the same as the inner diameter D2 of the small diameter section 33. The inner circumferential surface of the expanded diameter section 36 is smoothly connected to the inner circumferential surface of the large diameter section 34. The inner diameter of the expanded diameter section 36 at the downstream end is the same as the inner diameter D3 of the large diameter section 34. The expanded diameter section 36 is shorter than the small diameter section 33 in the direction of water flow. By providing the expanded diameter section 36, the occurrence of cavitation in the large diameter section 34 can be suppressed. Therefore, damage to the flow rate regulating pipe 32 and the first pipe 23 due to cavitation occurring in the large diameter portion 34 can be suppressed.

[0036] [Effects of the embodiment] As described above, the water heater 1 of the embodiment is a water heater 1 equipped with a bypass pipe 30 that short-circuits the water inlet passage 10 and the water outlet passage 20, and the bypass pipe 30 comprises a bypass pipe main body 31 and a flow rate regulating pipe 32 that connects the bypass pipe main body 31 and the water outlet passage 20 and regulates the water flow rate, and the flow rate regulating pipe 32 comprises a small diameter section 33 that is smaller in diameter than the bypass pipe main body 31, and a large diameter section 34 that is connected downstream of the small diameter section 33 and has a diameter larger than that of the small diameter section 33.

[0037] With this configuration, the bypass ratio can be controlled by the small diameter section 33, while the flow velocity can be reduced in the large diameter section 34 downstream of the small diameter section 33. As a result, when the water flows from the bypass pipe 30 into the hot water outlet passage 20, the force with which the water collides with the piping (first piping 23) that constitutes the hot water outlet passage 20 can be weakened, and erosion of the piping that constitutes the hot water outlet passage 20 can be suppressed.

[0038] In this embodiment, the large diameter portion 34 is provided longer than the small diameter portion 33 in the direction in which water flows.

[0039] With this configuration, the effect of reducing the flow velocity in the large diameter portion 34 can be further enhanced, and erosion of the piping that constitutes the melt discharge passage 20 can be further suppressed.

[0040] In the embodiment, the flow rate regulating pipe 32 further includes a reduced diameter section 35 arranged at the upstream end of the flow rate regulating pipe 32, and the diameter of the reduced diameter section 35 gradually decreases from the upstream side to the downstream side, and the downstream end of the reduced diameter section 35 is connected to the upstream end of the small diameter section 33.

[0041] This configuration can suppress the occurrence of cavitation in the small diameter portion 33. Therefore, damage to the flow rate regulating pipe 32 and the pipes that make up the melt discharge path 20 due to cavitation occurring in the small diameter portion 33 can be suppressed.

[0042] <Other embodiments> (1) The outer shape of the flow rate regulating pipe may be modified as appropriate within the scope of achieving the object of the present disclosure. For example, the shape and connection method of the connection portion between the flow rate regulating pipe and the outlet channel, and the connection portion between the flow rate regulating pipe and the bypass pipe main body may be different from those in the above embodiment.

[0043] (2) In the above embodiment, the flow rate regulating pipe 32 has the enlarged diameter portion 36, but the flow rate regulating pipe does not have to have an enlarged diameter portion. [Explanation of symbols]

[0044] 1: Water heater 10: Inlet water channel 10A: Branching section 11: Inlet water temperature sensor 12: Water governor 13: Flow rate sensor 20: Hot water outlet passage 20A: Confluence 21: Inner body temperature sensor 22: Hot water outlet temperature sensor 23: First pipe 23A: Insertion hole 23B: First connection portion 23C: Opposing wall portion 30: Bypass pipe 31: Bypass pipe body 31A: Second connecting portion 31B: Straight portion 31C: Bent portion 32: Flow rate regulation tube 32A: First end 32B: Second end 32C: Main body 33: Small diameter section 34: Large diameter section 35: Reduced diameter section 36: Expanded diameter section 40: Heat exchanger 50: Burner 60: Controller 61: Remote control 70: Gas supply line 71: Main solenoid valve 72: Main solenoid valve 73: Proportional valve D1: Inner diameter of bypass pipe body 31 D2: inner diameter of the small diameter portion 33 D3: Inner diameter of the large diameter portion 34

Claims

1. A water heater equipped with a bypass pipe that short-circuits the water inlet and water outlet, the bypass pipe includes a bypass pipe body and a flow rate regulating pipe that connects the bypass pipe body and the hot water outlet passage and regulates the flow rate of water; The water heater, wherein the flow rate regulating pipe comprises a small diameter section having a diameter smaller than that of the bypass pipe main body, and a large diameter section connected to the downstream side of the small diameter section and having a diameter larger than that of the small diameter section.

2. The water heater according to claim 1 , wherein the large diameter portion is longer than the small diameter portion in the direction of water flow.

3. the flow rate regulating pipe further includes a reduced diameter portion disposed at an upstream end of the flow rate regulating pipe, The diameter of the reduced diameter portion gradually decreases from the upstream side to the downstream side, The water heater according to claim 1 or 2, wherein a downstream end of the reduced diameter portion is continuous with an upstream end of the small diameter portion.

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