JP2021156538A - Water heater - Google Patents

Abstract

To provide a water heater capable of keeping adhesion to a valve seat in a closing state of a check valve of a break-off valve unit.SOLUTION: A break-off valve unit 2 includes a flow channel 95 in an upper lateral direction portion 51 of a third casing 5. The flow channel 95 is branched to a flow channel 97 at a branch portion 951. A break-off check valve is disposed in the flow channel 97. A check valve unit 20 is disposed in the upper lateral direction portion 51. The check valve unit 20 includes an annular supporting portion 263, and three installation portions 262. Three installation portions 262 are extended in a shaft center direction from an inner wall portion of the check valve unit 20 and support the annular supporting portion 263 on a shaft center of a first member 21. The annular supporting portion 263 supports a first check valve 70. The annular supporting portion 263 and three installation portions 262 are located on the upstream side of the flow channel 97, and supported by the inner wall portion of the upper lateral direction portion 51. Thus the first check valve 70 can be made to approach a first valve seat 515 located on the upstream side of the flow channel 97.SELECTED DRAWING: Figure 6

Description

The present invention relates to a water heater.

Conventionally, in a water heater, an edge cut valve unit is provided in a pipeline connecting a hot water supply circuit and a circulation heating circuit. The edge cut valve unit prevents backflow of hot water from the circulation heating circuit side to the hot water supply circuit side. The edge cut valve unit includes a main flow path and a casing provided with a branch path branching from the main flow path. Two check valves are provided in the main flow path in the casing so as to urge the upstream side and the downstream side of the position of branching to the branch path from the downstream side in a direction of blocking. The branch path is provided with an edge cutting valve that opens the branch path when the pressure on the circulation heating circuit side increases. As a result, when the pressure on the circulation heating circuit side increases relatively and hot water enters the edge-cutting valve unit beyond the check valve on the downstream side, the entered hot water flows through the branch path and is external from the edge-cutting valve. Is discharged to.

As an example of the edge cut valve unit, a control valve unit in which an on-off valve, two check valves, and an air release valve are assembled in a common cylindrical casing is known (see, for example, Patent Document 1). In this control valve unit, two check valves are assembled linearly and coaxially on a cylindrical body to form a unit, which is inserted and fixed in the main flow path in the casing.

Japanese Unexamined Patent Publication No. 2018-91396

However, in the above control valve unit, since the body is supported by the casing only on the downstream side of the branch path in the main flow path, the support position of the check valve on the upstream side and the valve seat provided in the main flow path are provided. Since the distance to the check valve becomes long, the check valve has to make the advance / retreat stroke longer. For this reason, the water flow pressure from the hot water supply circuit is applied to the check valve on the upstream side, and when moving to the downstream side, the shaft of the check valve may be shaken, and the adhesion with the valve seat in the closed state may be weakened. there were.

An object of the present invention is to provide a water heater capable of maintaining close contact with a valve seat in a closed state of a check valve of an edge cut valve unit.

The water heater according to claim 1 is a water heater in which a check valve unit for preventing a check valve unit for preventing backflow of hot water from the circulation heating circuit side to the hot water supply circuit side is provided in a pipeline connecting the hot water supply circuit and the circulation heating circuit. The check valve unit is branched from a main flow path that extends linearly from the upstream opening in the direction in which hot water flows toward the downstream opening and a branch portion provided in the main flow path, and is constantly opened in the valve opening direction by spring force. The main flow path and the branch path are provided with a branch path provided with a check valve which is urged by the hot water supply circuit and is urged in the valve closing direction against the spring force by receiving the back pressure from the hot water supply circuit. A casing provided with a first valve seat on the peripheral edge of the upstream opening, a cylindrical cylindrical portion provided on the casing in which the main flow path is formed inside, and the first valve seat are separated from each other to circulate. A first check valve that prevents backflow of hot water from the heating circuit side and a second check valve that is located downstream of the first check valve and prevents backflow of hot water from the circulation heating circuit side. The check valve is inserted into the main flow path from the downstream opening so that the first check valve faces the first valve seat and can be contacted and separated, and is arranged in the cylindrical portion. The check valve unit includes a valve unit, the check valve unit includes a first member and a second member arranged on the downstream side of the first member, and the first member is formed in a cylindrical shape on the upstream side. The first support portion provided in the A plurality of erection portions supported on the axis of one member, a second valve seat provided on the downstream side of the first support portion and in contact with and detached from the second check valve, the first support portion and the said A second support portion provided on the body portion between the second valve seats and provided with a communication port for communicating the branch path and the first member, the second member supporting the second check valve. In the check valve unit, the second valve seat is located closer to the second support portion than the branch passage, and the plurality of erection portions are located closer to the first valve seat than the branch passage. It is characterized in that it is arranged in the main flow path so as to be located on the side, and the second valve seat and the plurality of erection portions are supported by the inner wall portion of the cylindrical portion.

The first member of the water heater according to claim 2 includes an annular connecting portion that connects with the plurality of erection portions, and the connecting portion is in a state where the check valve unit is arranged in the cylindrical portion. The cylindrical portion may be in close contact with the inner wall portion on the upstream side of the branch path.

The inner wall portion of the cylindrical portion of the water heater according to claim 3 is fitted with a fitting portion provided in the check valve unit, and the check valve unit rotates in the circumferential direction with respect to the casing. A fitted portion may be provided to regulate the above.

The cylindrical portion of the water heater according to claim 4 has a cylindrical small-diameter portion in which the first member is arranged inside and a cylindrical portion that is provided on the downstream side of the small-diameter portion and has a larger diameter than the small-diameter portion. The large-diameter portion and the cylindrical medium-diameter portion provided between the small-diameter portion and the large-diameter portion are provided, and inside the cylindrical portion, between the large-diameter portion and the medium-diameter portion. A step portion that reduces the diameter inward in the radial direction is provided, and the fitting portion protrudes outward in the radial direction from the outer peripheral portion of the first member and is parallel to the axial direction of the first member. The fitted portion is provided in the middle diameter portion, extends from the step portion in the middle diameter portion in parallel with the axial direction of the casing, and fits with the fitting portion. The second member is a notch or groove to be fitted, and the second member is formed along the inner wall portion of the large-diameter portion in a state of being arranged in the cylindrical portion, and the downstream end portion thereof is the medium-diameter portion. An O-ring is arranged on the downstream side of the tubular portion, and a cylindrical positioning member is inserted into the peripheral edge of the downstream opening of the casing. The O-ring is fixed and sandwiched between the downstream end of the cylindrical portion and the positioning member from the upstream side and the downstream side along the inner wall portion of the downstream opening. May be good.

According to the water heater of claim 1, since the erection portion is located on the upstream side of the branch path, the distance between the first support portion and the first valve seat is shortened. As a result, the advance / retreat stroke of the first check valve is shortened, so that the axis deviation of the first check valve in the cylindrical portion can be prevented. Therefore, the water heater can maintain the close contact with the first valve seat in the closed state of the first check valve in the edge cut valve unit.

According to the water heater of claim 2, since the first support portion is supported from the entire circumference by the inner wall portion on the upstream side of the cylindrical portion via the plurality of erection portions and the connecting portions, the shaft of the first check valve The deviation can be further prevented.

According to the water heater of claim 3, since the check valve unit can be prevented from rotating in the cylindrical portion of the casing, the state in which the communication passage of the first member and the branch path overlap can be maintained, and the first member can be maintained. The state of communication between the inside and the branch road can be guaranteed. As a result, the water heater can improve the discharge performance of the backflow water in the branch path when the backflow of hot water occurs.

According to the water heater of claim 4, the fitting portion provided on the outer peripheral portion of the first member extends to the downstream end portion of the first member, so that the downstream end portion of the first member has a circular shape. Since a part of the portion has a shape protruding outward in the radial direction, the shape is not a perfect circle. Therefore, in the present application, the fitting portion is covered from the downstream side by the second member located on the downstream side of the first member, and the O-ring is sandwiched between the second member and the positioning member. Therefore, the sealing property by the O-ring can be guaranteed.

It is a perspective view of the water heater 1. It is an internal block diagram of a water heater 1. It is a perspective view of the edge cutting valve unit 2. FIG. 3 is a cross-sectional view taken along the line II in the direction of arrow shown in FIG. FIG. 3 is a cross-sectional view taken along the line II-II shown in FIG. It is a partially enlarged view of the upper part of the edge cut valve unit 2 shown in FIG. It is an exploded perspective view of the 3rd casing 5, the check valve unit 20, and the lid member 57.

Hereinafter, embodiments of the present invention will be described. Unless otherwise specified, the structure of the device described below is not intended to be limited thereto, but is merely an example of explanation. The drawings are used to illustrate the technical features that can be adopted by the present invention.

The configuration of the water heater 1 will be briefly described with reference to FIGS. 1 and 2. As shown in FIG. 1, the water heater 1 includes a housing 1A and a lid 1B. The bottom of the housing 1A is provided with a water supply connection port 37, a hot water supply connection port 36, a gas connection port 38, and a drainage port 39 shown in FIG. When the lid 1B is removed from the front surface of the housing 1A, the inside of the housing 1A is exposed. As shown in FIG. 2, a hot water supply circuit 11, a circulation heating circuit 12, a hot water supply pipe 206, an edge cut valve unit 2, and the like are provided inside the housing 1A. Note that FIG. 2 is an easy-to-understand illustration of the arrangement of each configuration in the housing 1A, and the orientation of each pipe is partially different from the actual orientation of the piping.

The hot water supply circuit 11 includes an inflow pipe 101, a hot water supply burner 102, a primary heat exchanger 103, a secondary heat exchanger 104, a hot water outlet pipe 105, a branch pipe 106, and the like. The hot water supply burner 102, the primary heat exchanger 103, and the secondary heat exchanger 104 are provided in the combustion chamber 8. The water flowing in from the water supply connection port 37 flows through the inflow pipe 101, and then flows in the order of the secondary heat exchanger 104 and the primary heat exchanger 103. The primary heat exchanger 103 recovers the sensible heat in the combustion exhaust from the hot water supply burner 102, and the secondary heat exchanger 104 recovers the latent heat in the combustion exhaust from the hot water supply burner 102 to heat the water flow. The hot water outlet pipe 105 is connected between the outlet of the primary heat exchanger 103 and the connection port 35 (see FIG. 3) of the edge cut valve unit 2, which will be described later. The hot water heated in the primary heat exchanger 103 and the secondary heat exchanger 104 flows through the hot water outlet pipe 105 and is supplied to the outside from the hot water supply connection port 36 via the edge cut valve unit 2 (see arrow B shown in FIG. 3). ). The branch pipe 106 branches on the upstream side of the inflow pipe 101 and is connected to the connection port 67 (see FIG. 3) of the inflow pipe 633 described later in the edge cut valve unit 2.

The circulation heating circuit 12 includes a bath return pipe 201, a bath going pipe 202, a bath burner 203, a bath primary heat exchanger 204, a bath secondary heat exchanger 205, a hot water supply pipe 206, a pump 207, and the like. The bath burner 203, the bath primary heat exchanger 204, and the bath secondary heat exchanger 205 are provided in the combustion chamber 8. The bath return pipe 201 is connected between the downstream end of the pipe 13 extending from the bathtub 9 and the inlet of the bath secondary heat exchanger 205. The pump 207 is provided in the middle of the bath return pipe 201. The bath primary heat exchanger 204 mainly recovers the sensible heat in the combustion exhaust from the bath burner 203, and the bath secondary heat exchanger 205 mainly recovers the latent heat in the combustion exhaust from the bath burner 203. Heat the water flow. The bath going pipe 202 is connected between the outlet of the bath primary heat exchanger 204 and the upstream end of the pipe 14 extending from the bathtub 9. By driving the pump 207, the hot water in the bathtub 9 flows in the order of the pipe 13, the bath return pipe 201, the bath secondary heat exchanger 205, the bath primary heat exchanger 204, the bath going pipe 202, and the pipe 14, and circulates with the bathtub 9. It circulates between the heating circuits 12.

The hot water supply pipe 206 is provided between the hot water supply circuit 11 and the circulation heating circuit 12, and supplies hot water from the hot water supply circuit 11 to the circulation heating circuit 12. The upstream end of the hot water supply pipe 206 is connected to a connection port 58, which will be described later, of the edge cutting valve unit 2. The downstream end of the hot water supply pipe 206 is connected to the upstream side of the pump 207 of the bath return pipe 201. The edge cut valve unit 2 is provided in the hot water supply pipe 206. The edge cut valve unit 2 prevents the backflow of hot water from the circulation heating circuit 12 side to the hot water supply circuit 11 side.

The gas flows into the gas pipe 7 from the gas connection port 38 and is supplied to the hot water supply burner 102 and the bath burner 203 in the combustion chamber 8, respectively. Overflow water and drain water are discharged from the drain port 39. The overflow water is hot water that has flowed back into the edge cut valve unit 2 from the circulation heating circuit 12 via the hot water supply pipe 206, flows through the overflow pipe 110 described later, and is discharged to the outside from the drain port 39. The drain water is generated by the secondary heat exchanger 104 and the bath secondary heat exchanger 205.

The structure of the edge cut valve unit 2 will be described with reference to FIGS. 3 to 6. As shown in FIGS. 3 and 4, the check valve unit 2 includes a second casing 4, a third casing 5, and a fourth casing 6 connected to the first casing 3 (casing 3 to 6 when collectively referred to hereinafter). A check valve unit 20, a third check valve 72, and an edge-cutting valve 73 are provided. Casings 3 to 6 are made of resin. That is, the edge cut valve unit 2 is composed of a second casing 4, a third casing 5, and a fourth casing 6, and the first casing 3 connected to the second casing 4 is downstream of the hot water outlet pipe 105 of the hot water supply circuit 11. It constitutes a part of the side (see FIG. 2).

The first casing 3 is formed in a substantially T shape tilted clockwise by approximately 90 ° when viewed from the right side, and includes a lateral portion 31 (see FIG. 3) and a vertical portion 32. The lateral portion 31 is formed in a substantially cylindrical shape extending in the front-rear direction, and the rear end portion is closed. A connection port 35 is provided at the front end of the lateral portion 31. The connection port 35 opens toward the front. A flow path 91 is provided inside the lateral portion 31. The flow path 91 extends rearward from the connection port 35. The downstream end of the hot water pipe 105 (see FIG. 2) is connected to the connection port 35.

The vertical portion 32 is formed in a substantially cylindrical shape extending in the vertical direction. The substantially intermediate portion in the vertical direction of the vertical portion 32 is connected to the rear portion of the left surface of the lateral portion 31. A hot water supply connection port 36 is provided at the lower end of the vertical portion 32. The hot water supply connection port 36 opens downward. The hot water supply connection port 36 is provided at the bottom of the water heater 1. A pipe (not shown) connected to the faucet is connected to the hot water supply connection port 36. A flow path 92 (see FIG. 4) is provided inside the vertical portion 32. The flow path 92 extends upward from the hot water supply connection port 36. The flow path 92 communicates with the rear end portion of the flow path 91 of the lateral direction portion 31 at a substantially intermediate portion in the vertical direction.

The second casing 4 is formed in a substantially T-shape when viewed from the right side, and includes a vertical direction portion 41 and a horizontal direction portion 42. The vertical portion 41 is formed in a substantially cylindrical shape extending in the vertical direction. The lower end of the vertical portion 41 is fixed to the upper end of the vertical portion 32 of the first casing 3 with two screws 301. A flow path 93 (see FIG. 4) is provided inside the vertical portion 41. The flow path 93 extends in the vertical direction. A metal filter 44 is provided at the upper end of the flow path 93. The lateral portion 42 is formed in a substantially cylindrical shape extending in the front-rear direction. The upper end portion of the vertical portion 41 is connected to the lower portion of the substantially intermediate portion in the longitudinal direction of the lateral portion 42. A flow path 94 is provided inside the lateral portion 42. The flow path 94 extends in the front-rear direction. The rear end of the flow path 94 communicates with the upper end of the flow path 93. A solenoid valve 45 is provided at the rear end of the lateral portion 42. The solenoid valve 45 opens and closes the flow path 94 by exciting or not exciting the electromagnet 451. A water amount sensor 46 is provided on the front end side of the flow path 94. The water amount sensor 46 measures the amount of hot water flowing through the flow path 94.

The third casing 5 includes an upper lateral portion 51, a lower lateral portion 52, a vertical portion 53, and a connecting portion 54. The upper lateral portion 51 has a substantially cylindrical shape extending in the front-rear direction, and is provided coaxially with the lateral portion 42 of the second casing 4. A flow path 95 (see FIG. 4) is provided inside the upper lateral portion 51. The flow path 95 extends in the front-rear direction.

The upper lateral portion 51 includes a small diameter portion 511, a medium diameter portion 512, and a large diameter portion 513 in this order from the rear to the front. The small diameter portion 511 forms a portion from the rear end portion of the upper lateral direction portion 51 to a substantially intermediate portion in the longitudinal direction. A branch portion 951 is provided at the lower portion on the front end side of the inner wall surface of the small diameter portion 511 (see FIG. 4). The branch portion 951 branches from the flow path 95 to the flow path 97 of the vertical direction portion 53, which will be described later. An opening 60 (see FIGS. 6 and 7) through which hot water flows from the second casing 4 is provided at the rear end of the small diameter portion 511. A first valve seat 515 (see FIGS. 4 and 6) is provided on the peripheral edge of the opening 60. The first valve seat 515 is formed in a substantially annular shape through which the central portion penetrates. The valve body 701 (see FIG. 6) of the first check valve 70, which will be described later, comes into contact with the front surface of the first valve seat 515. The rear end portion of the small diameter portion 511 is fixed to the front end portion of the lateral portion 42 of the second casing 4 with two screws 302.

The large diameter portion 513 forms a front end side portion of the upper lateral direction portion 51, and is larger than the diameter of the small diameter portion 511. An opening 59 is provided at the front end of the large diameter portion 513 (see FIG. 7). A pair of fixing cylinders 517 are provided on both the left and right sides of the opening 59. Each of the pair of fixing cylinders 517 extends in the front-rear direction and is formed in a substantially cylindrical shape. Each of the pair of fixing cylinders 517 is provided with a fixing hole 518 extending rearward from the front end. The lid member 57 is fastened to the pair of fixing holes 518 with two screws 303 in a state where the check valve unit 20 described later is inserted into the opening 59 from the front to the inside.

The medium diameter portion 512 forms a portion between the small diameter portion 511 and the large diameter portion 513. The medium diameter portion 512 has a larger diameter than the small diameter portion 511 and has a smaller diameter than the large diameter portion 513. A communication hole 952 is provided in the lower part of the inner wall surface of the medium diameter portion 512. The flow path 95 communicates with the upper end portion of the communication passage 541 of the connecting portion 54, which will be described later, via the communication hole 952. Inside the upper lateral portion 51, a step portion 519 is provided between the medium diameter portion 512 and the large diameter portion 513 (see FIG. 7). The step portion 519 has a diameter reduced inward in the radial direction and faces the front. A fitting groove 516 is provided on the front end side of the left portion of the inner wall surface of the medium diameter portion 512. The fitting groove 516 extends linearly from the front end of the medium diameter portion 512 toward the rear. The front end of the fitting groove 516 penetrates forward at the step portion 519.

The lower lateral portion 52 is arranged below the upper lateral portion 51 (see FIGS. 3 and 4). The lower lateral portion 52 is formed in a substantially cylindrical shape extending parallel to the upper lateral portion 51 and in the front-rear direction. A flow path 96 is provided inside the lower lateral portion 52. The flow path 96 extends in the front-rear direction. The lower lateral portion 52 includes a small diameter portion 521 and a large diameter portion 522 in this order from the rear to the front. The small diameter portion 521 is arranged below the medium diameter portion 512 of the upper lateral direction portion 51 and has substantially the same shape as the medium diameter portion 512. The large-diameter portion 522 is arranged below the large-diameter portion 513 of the upper lateral portion 51, and is larger than the diameter of the small-diameter portion 521. A connection port 58 is provided at the front end of the large diameter portion 522. The connection port 58 opens toward the front. The upstream end of the hot water supply pipe 206 (see FIG. 2) extending from the circulation heating circuit 12 side is connected to the connection port 58. A communication hole 961 (see FIG. 4) is provided in the upper part of the inner wall surface of the small diameter portion 521. The flow path 96 communicates with the lower end of the communication passage 541 of the connecting portion 54, which will be described later, via the communication hole 961.

The connecting portion 54 is provided between the upper lateral direction portion 51 and the lower lateral direction portion 52, and connects the upper lateral direction portion 51 and the lower lateral direction portion 52 to each other. The connecting portion 54 is provided with a communication passage 541 (see FIG. 4) extending in the vertical direction. The upper end portion of the communication passage 541 communicates with the flow path 95 through a communication hole 952 provided in the inner wall portion of the middle diameter portion 512 of the upper lateral direction portion 51. The lower end of the communication passage 541 communicates with the flow path 96 through the communication hole 961 provided in the inner wall portion of the small diameter portion 521 of the lower lateral portion 52.

The vertical portion 53 extends downward from the lower front portion of the small diameter portion 511 of the upper lateral portion 51, and is formed in a substantially cylindrical shape. A flow path 97 is provided inside the vertical portion 53. The flow path 97 extends in the vertical direction. The upper end portion of the flow path 97 communicates with the flow path 95 via a branch portion 951 provided on the inner wall portion of the small diameter portion 511. A communication hole 971 is provided at a position of the inner wall portion of the vertical portion 53 and facing the rear end portion of the lower lateral portion 52. The flow path 97 communicates with the flow path 96 through the communication hole 971.

The fourth casing 6 includes a vertical portion 61, a valve accommodating portion 62, and a lid portion 63. The vertical portion 61 has a substantially cylindrical shape extending in the vertical direction. A flow path 98 is provided inside the vertical portion 61. The flow path 98 extends in the vertical direction. A flow path 99 (see FIGS. 4 and 5) is provided at the lower end of the vertical portion 61. The flow path 99 extends to the right from the lower end of the flow path 98. The upper end of the vertical portion 61 is fixed to the lower end of the vertical portion 53 of the third casing 5 and the lower portion of the lower lateral portion 52 with two screws 304. The flow path 98 communicates with the flow path 97 of the vertical portion 53 of the third casing 5.

The valve accommodating portion 62 is integrally provided at the lower part of the right side surface of the vertical portion 61 (see FIG. 4). The valve accommodating portion 62 is formed in a substantially rectangular shape tilted clockwise on the right side surface and in a box shape with the right side surface open. A communication hole 621 is provided on the left wall surface inside the valve accommodating portion 62. The inside of the valve accommodating portion 62 communicates with the right end portion of the flow path 99 through the communication hole 621. A drainage pipe 632 (see FIG. 3) is provided so as to project forward on the front side of the valve accommodating portion 62 and on the side surface facing diagonally downward. The inside of the drain pipe 632 communicates with the inside of the valve accommodating portion 62. A connection port 66 is provided at the front end of the drain pipe 632. The connection port 66 opens toward the front. The upstream end of the overflow pipe 110 (see FIG. 2) is connected to the connection port 66. The downstream end of the overflow pipe 110 is connected to a drain port 39 (see FIG. 2) at the bottom of the housing 1A.

The lid portion 63 is formed in a substantially rectangular shape tilted clockwise by approximately 45 ° when viewed from the right side surface, and is fixed by four screws 305 so as to close the opening right side surface of the valve housing portion 62. A circular recess 631 is provided at a substantially central portion of the lid 63. The recessed portion 631 is formed by recessing the left surface of the lid portion 63 toward the right. An inflow pipe 633 is provided on the right surface of the lid portion 63 so as to be bent forward. The inside of the inflow pipe 633 communicates with the inside of the recess 631. A connection port 67 is provided at the front end of the inflow pipe 633. The connection port 67 opens toward the front. A downstream end of a branch pipe 106 (see FIG. 2) extending from the hot water supply circuit 11 is connected to the connection port 67.

The structure of the check valve unit 20 will be described with reference to FIGS. 6 and 7. As shown in FIG. 6, the check valve unit 20 is inserted into the flow path 95 from the opening 59 of the upper lateral portion 51 of the third casing 5 and arranged. As shown in FIG. 7, the check valve unit 20 includes a first member 21 and a second member 22 in this order from the rear.

The structure of the first member 21 will be described. The first member 21 is formed in a substantially cylindrical shape extending in the front-rear direction. The first member 21 includes a front body portion 24, a rear body portion 25, and a valve support portion 26 in this order from the front side. The front body portion 24 is formed in a substantially cylindrical shape. A protrusion 242 is provided on the front end side of the left side portion of the outer peripheral surface of the front body portion 24. The protrusion 242 protrudes to the left and extends linearly from the front end of the front body portion 24 toward the rear. A second valve seat 241 is provided at the rear end of the front body portion 24. The second valve seat 241 is formed in a substantially annular shape through which the central portion penetrates. The valve body 711 of the second check valve 71, which will be described later, comes into contact with the front surface of the second valve seat 241 from the front. A communication port 243 having a substantially rectangular shape on the bottom surface is provided on the rear side of the lower portion of the front body portion 24. A slit 245 is provided on the front side of the lower portion of the front body portion 24. The slit 245 extends rearward from the front end portion of the front side body portion 24 and communicates with the communication port 243. A protruding portion 275, which will be described later, provided in the second member 22 is inserted into the slit 245 from the front and fitted. A claw portion 246 is provided at the right end portion of the pair of end portions facing each other forming the slit 245. The claw portion 246 projects obliquely upward with respect to the inside of the front body portion 24. The rear body portion 25 extends coaxially rearward from the rear end portion of the front body portion 24 and is formed in a substantially cylindrical shape. A communication port 251 having a substantially rectangular shape on the bottom surface is provided on the lower side of the rear body portion 25. A groove 29 having a semicircular cross section is provided along the outer circumference of the boundary portion between the front side body portion 24 and the rear side body portion 25. A resin O-ring 81 having an annular shape in front view is mounted on the groove 29.

The valve support portion 26 is provided at the rear end portion of the rear side body portion 25. The valve support portion 26 includes a connecting portion 261 and three erection portions 262 (two in FIG. 6 and only one in FIG. 7), and an annular support portion 263. The connecting portion 261 is formed in an annular shape. The three erection portions 262 extend in a beam shape from three positions at the inner edge portion of the connecting portion 261 at equal intervals in the circumferential direction toward the central axis. The annular support portion 263 is arranged at the axial center of the connecting portion 261. The annular support portion 263 extends in the front-rear direction and is formed in a substantially cylindrical shape having a diameter shorter than that of the connecting portion 261. One ends of each of the three erection portions 262 are connected to the outer peripheral portion of the annular support portion 263. Therefore, the annular support portion 263 is supported by the three erection portions 262 at the axial center of the connecting portion 261.

The valve shaft 702 of the first check valve 70 is inserted in the front-rear direction inside the annular support portion 263. A valve body 701 is provided at the rear end of the valve shaft 702. The valve body 701 is formed in a substantially columnar shape having a diameter larger than that of the valve shaft 702. The valve body 701 is stably and movably supported in the front-rear direction by the annular support portion 263 via the valve shaft 702. As a result, the valve body 701 is arranged so as to be in contact with and detachable from the first valve seat 515 provided at the rear end portion of the upper lateral portion 51 of the third casing 5. A cylindrical spring 705 is mounted on the outside of the valve shaft 702. The front end of the spring 705 abuts on the rear surface of the three erections 262, and the rear end of the spring 705 abuts on the front surface of the valve body 701. As a result, the valve body 701 is constantly urged in the direction (rearward) in contact with the first valve seat 515 by the spring force of the spring 705. Therefore, the first check valve 70 shuts off the hot water flowing back through the flow path 95 from the front to the rear by the spring force of the spring 705.

The structure of the second member 22 will be described. The second member 22 is arranged on the front side (downstream side) of the first member 21. The second member 22 includes a valve support portion 27. Similar to the valve support portion 26 of the first member 21, the valve support portion 27 includes a connecting portion 271, three erection portions 272 (only two are shown in FIG. 6), an annular support portion 273, and a tubular portion 274. Be prepared. The connecting portion 271 is formed in an annular shape. The three erection portions 272 extend in a beam shape from three positions at the inner edge portion of the connecting portion 271 at equal intervals in the circumferential direction toward the central axis. The annular support portion 273 is arranged at the axial center of the connecting portion 271. The annular support portion 273 extends in the front-rear direction and is formed in a substantially cylindrical shape having a diameter shorter than that of the connecting portion 271, and is connected to one end of each of the three erection portions 272 at the outer peripheral portion thereof. Therefore, the annular support portion 273 is supported by the three erection portions 272 at the axial center of the connecting portion 271.

The valve shaft 712 of the second check valve 71 is inserted in the front-rear direction inside the annular support portion 273. A valve body 711 is provided at the rear end of the valve shaft 712. The valve body 711 is formed in a substantially columnar shape having a diameter longer than that of the valve shaft 712. The valve body 711 is stably and movably supported in the front-rear direction by the annular support portion 273 via the valve shaft 712. Therefore, the valve body 711 is arranged so as to be in contact with and detachable from the second valve seat 241 of the first member 21. A cylindrical spring 715 is mounted on the outside of the valve shaft 712. The front end of the spring 715 abuts on the rear surface of the three erections 272, and the rear end of the spring 715 abuts on the front surface of the valve body 711. As a result, the valve body 711 is constantly urged in the direction (rearward) in contact with the second valve seat 241 by the spring force of the spring 715. The tubular portion 274 projects forward from the outer peripheral portion of the front surface of the connecting portion 271 and is formed in a substantially annular shape in front view. The front end faces of the tubular portion 274 face forward. A protruding portion 275 is provided at the lower part of the outer peripheral surface of the connecting portion 271. The projecting portion 275 projects downward.

The structure of the lid member 57 will be described. The lid member 57 has a substantially disk shape formed in a substantially circular shape when viewed from the front. Fixing holes 571 penetrating in the front-rear direction are provided at both left and right ends of the lid member 57, respectively. A substantially cylindrical tubular portion 572 that projects rearward is provided on the rear surface of the lid member 57. The tubular portion 572 includes a large diameter portion 573 and a small diameter portion 574 (see FIG. 6). The large-diameter portion 573 is provided on the front side of the tubular portion 572, and the small-diameter portion 574 is provided on the rear side of the tubular portion 57 2. A step portion 575 (see FIG. 6) is provided between the large diameter portion 573 and the small diameter portion 574. The step portion 575 faces rearward. A resin O-ring 82 is attached to the outside of the small diameter portion 574. The O-ring 82 comes into contact with the step portion 575.

A method of attaching the check valve unit 20 to the upper lateral portion 51 of the third casing 5 will be described with reference to FIGS. 6 and 7. As shown in FIG. 7, first, the second member 22 is inserted and combined inside the front body portion 24 of the first member 21. At this time, the protruding portion 275 provided in the second member 22 is inserted into the slit 245 provided in the lower part of the front body portion 24 of the first member 21. The protruding portion 275 is fitted to the slit 245, and the claw portion 246 is locked to the protruding portion 275. As a result, it is possible to prevent the second member 22 from rotating inside the front body portion 24 of the first member 21. The valve body 711 of the second check valve 71 projecting from the rear end side of the second member 22 comes into contact with the second valve seat 241 provided inside the first member 21 from the front. In this way, the check valve unit 20 is completed.

Next, the check valve unit 20 is inserted from the opening 59 into the inside of the upper lateral portion 51. At this time, the protruding portion 242 provided on the outer peripheral surface of the first member 21 is inserted from the front end of the fitting groove 516 provided in the inner step portion 519 of the upper lateral direction portion 51 and pushed backward. The protrusion 242 fits with the fitting groove 516. The first member 21 is arranged in the upper lateral portion 51. In the upper lateral portion 51, the valve support portion 26 of the first member 21 is arranged on the inner wall surface on the upstream side of the flow path 97. The valve body 701 of the first check valve 70 comes into contact with the first valve seat 515 provided at the rear end of the upper lateral portion 51 (see FIG. 6). As a result, the check valve unit 20 is arranged in the upper lateral portion 51.

Finally, the lid member 57 is fixed to the opening 59 of the upper lateral portion 51. At this time, the tubular portion 572 of the lid member 57 is inserted from the opening 59 into the inside of the upper lateral portion 51. In the upper lateral portion 51, the O-ring 82 is sandwiched between the stepped portion 575 of the tubular portion 572 and the front end surface of the tubular portion 274 of the second member 22. The outer peripheral portion of the rear surface of the lid member 57 is brought into contact with the rear end surface of the large diameter portion 513 of the upper lateral direction portion 51, and a pair of fixing holes 571 provided in the lid member 57 are provided on the front end side of the large diameter portion 513. Position it in the pair of fixing holes 514, and fasten the two screws 303 to fix it. As a result, the lid member 57 is fixed so as to close the opening 59 of the upper lateral portion 51, and the attachment of the check valve unit 20 to the upper lateral portion 51 is completed.

As shown in FIG. 6, in a state where the check valve unit 20 is arranged in the upper lateral direction portion 51, the communication port 251 of the rear side body portion 25 of the first member 21 is on the flow path 97 side located below. Directed to. As a result, the communication port 251 and the flow path 97 overlap each other, so that the inside of the first member 21 and the flow path 97 communicate with each other. Further, the communication port 243 of the front side body portion 24 of the first member 21 is directed to the communication passage 541 of the connecting portion 54 located below. As a result, the communication port 243 and the communication passage 541 overlap, so that the inside of the first member 21 and the communication passage 541 communicate with each other.

As shown in FIG. 4, the third check valve 72 is provided in the flow path 96 inside the small diameter portion 521 of the lower lateral portion 52 of the third casing 5. Although not described in detail, the third check valve 72 has the same structure as the first check valve 70 and the second check valve 71. The third check valve 72 uses a spring force to shut off the hot water flowing back from the flow path 96 toward the flow path 97 of the longitudinal portion 53 and the hot water flowing back from the flow path 96 toward the communication passage 541, respectively.

The edge cutting valve 73 is a well-known diaphragm valve, and includes a diaphragm film 731 and a spring 732. The spring 732 is arranged inside the flow path 99 provided at the lower end of the vertical portion 61 of the fourth casing 6. The diaphragm film 731 is housed inside the valve accommodating portion 62, and is arranged toward the left surface of the recessed portion 631 of the lid portion 63. The edge cutting valve 73 is always urged in the valve opening direction by the spring force of the spring 732. When water flows into the recess 631 from the branch pipe 106 extending from the hot water supply circuit 11 via the inflow pipe 633 (see FIG. 3) (see arrow D shown in FIG. 3), back pressure is applied to the diaphragm film 731. It takes. The diaphragm film 731 receives the back pressure of water and pushes down the spring 732. Therefore, the edge cutting valve 73 is urged and closed in the valve closing direction against the spring force of the spring 732.

The flow of hot water in the edge cut valve unit 2 will be described with reference to FIGS. 3 to 5. First, a case where hot water supplied from the hot water supply circuit 11 is supplied to the circulation heating circuit 12 will be described. The control unit (not shown) of the water heater 1 excites the electromagnet 451 of the second casing 4 and opens the solenoid valve 45. The hot water flowing from the hot water supply circuit 11 through the hot water outlet pipe 105 flows into the flow path 91 of the first casing 3 from the connection port 35 (see arrow A shown in FIG. 3), and flows along the flow paths 92 and 93 (FIG. 3). See arrow F shown in 4). Since the solenoid valve 45 is open, hot water passes through the filter 44 and flows into the flow path 94 of the second casing 4. The hot water flows forward through the flow path 94, flows into the flow path 95 of the third casing 5, and passes through the first check valve 70. The hot water flows forward in the flow path 95, and a part of the hot water branches at the branch portion 951 and flows downward in the flow path 97 in the vertical direction portion 53. The remaining hot water flows forward in the flow path 95. The hot water flowing forward through the flow path 95 passes through the second check valve 71 and flows into the communication passage 541 of the connecting portion 54 through the communication hole 952. Hot water flows downward through the passage 541.

The hot water that has flowed downward through the flow path 97 flows through the flow paths 98 and 99 of the vertical portion 61 of the fourth casing 6 and flows into the inside of the valve accommodating portion 62. As described above, since the edge cut valve 73 receives the back pressure of water from the hot water supply circuit 11 and is urged in the valve closing direction against the spring force, the flow path toward the drain pipe 632 is the edge cut valve 73. Is blocked by. Therefore, the hot water flowing downward through the flow path 97 flows into the flow path 96 of the lower lateral portion 52 through the communication hole 971. Hot water flows forward through the flow path 96 and passes through the third check valve 72 (see arrow C shown in FIG. 3). In this way, hot water is supplied from the connection port 58 to the circulation heating circuit 12 side via the hot water supply pipe 206 (see FIG. 2).

Next, a case where hot water flows backward from the circulation heating circuit 12 side toward the hot water supply circuit 11 side will be described. For example, when the pressure on the circulation heating circuit 12 side is higher than the pressure on the hot water supply circuit 11 side to some extent, the spring force in the edge cutting valve 73 overcomes the back pressure on the hot water supply circuit 11 side. Therefore, the edge cut valve 73 is opened by the spring force. When the pressure on the circulation heating circuit 12 side increases, the hot water in the circulation heating circuit 12 may flow into the flow path 96 from the connection port 58 via the hot water supply pipe 206 and flow back toward the rear. Since the flow path 96 is provided with the third check valve 72, the hot water flowing back through the flow path 96 is shut off by the third check valve 72.

Even if the hot water flowing back through the flow path 96 exceeds the third check valve 72, the flow path 97 in the vertical direction portion 53 of the third casing 5 and the flow path in the vertical direction portion 61 of the fourth casing 6. Both 98 extend in the vertical direction. Therefore, the edge cut valve unit 2 can drop hot water that has passed through the third check valve 72 along the flow paths 97 and 98. Hot water that has fallen along the flow paths 97 and 98 flows to the right in the flow path 99. As described above, since the edge cut valve 73 is open, the hot water flowing through the flow path 99 passes through the edge cut valve 73 and is discharged as overflow water from the drain pipe 632 (see arrow E shown in FIG. 3). The overflow water is discharged to the outside from the drain port 39 via the overflow pipe 110 (see FIG. 2).

Then, when the pressure difference between the circulation heating circuit 12 side and the hot water supply circuit 11 side becomes larger, the hot water flowing back through the flow path 96 vigorously exceeds the third check valve 72, and the flow path 97 maintains the momentum. , 98 may invade. Therefore, in the third casing 5 of the edge cut valve unit 2, a height difference is formed between the flow path 95 and the flow path 96 via the flow path 97 and the communication passage 541. Therefore, even if the pressure on the circulation heating circuit 12 side increases and the hot water exceeds the third check valve 72 in the flow path 96, the momentum weakens until the pressure flows up in the flow path 97 and the communication passage 541, respectively. Be done. The hot water that has flowed into the flow path 97 through the third check valve 72 falls along the flow paths 97 and 98 without reaching the flow path 95 of the upper lateral portion 51. On the other hand, the hot water that has flowed into the communication passage 541 beyond the third check valve 72 is shut off by the second check valve 71 even if it reaches the flow path 95. Therefore, the edge cut valve unit 2 can surely prevent the hot water flowing back from the circulation heating circuit 12 side from entering the hot water supply circuit 11 side.

With reference to FIGS. 6 and 7, the support structures of the first check valve 70 and the second check valve 71 by the check valve unit 20 and their effects will be described. As shown in FIG. 6, in the upper lateral direction portion 51, the valve support portion 26 of the first member 21 of the check valve unit 20 is located on the upstream side of the flow path 97. As a result, the first check valve 70 supported by the valve support portion 26 can be brought closer to the first valve seat 515 side in the upper lateral portion 51. As a result, the edge cut valve unit 2 can shorten the advancing / retreating stroke of the valve body 701 of the first check valve 70, so that the axis deviation of the first check valve 70 in the upper lateral direction portion 51 can be prevented. Further, the annular connecting portion 261 of the valve supporting portion 26 is in close contact with the inner wall portion on the upstream side of the flow path 97 inside the cylindrical upper lateral direction portion 51. As described above, the connecting portion 261 supports the annular support portion 263 via the three erection portions 262. As a result, the annular support portion 263 is supported from the entire circumference by the inner wall portion on the upstream side of the upper lateral direction portion 51 via the connecting portion 261 and the three erection portions 262. Therefore, the edge cut valve unit 2 can more effectively prevent the axis deviation of the first check valve 70 in the upper lateral portion 51.

Further, the protrusion 242 provided on the left side of the outer peripheral surface of the first member 21 fits into the fitting groove 516 provided on the left side of the inner wall surface of the upper lateral direction portion 51. This makes it possible to prevent the check valve unit 20 from rotating in the circumferential direction within the upper lateral portion 51. Therefore, the edge cut valve unit 2 can maintain the state in which the communication port 251 of the first member 21 and the flow path 97 overlap each other, so that the communication state between the inside of the first member 21 and the flow path 97 can be ensured. Therefore, the water heater 1 can improve the discharge performance of the backflow water in the flow path 97 when the backflow of hot water occurs.

Further, since the protrusion 242 extends to the downstream end of the front body 24 of the first member 21, a part of the circular portion of the downstream end of the first member 21 protrudes outward in the radial direction. It becomes a shape. For this reason, the downstream end of the first member 21 does not have a perfect circular shape. Therefore, in the present embodiment, the protrusion 242 is covered from the downstream side by the second member 22. Further, the O-ring 82 is sandwiched between the downstream end of the second member 22 and the stepped portion 575 of the tubular portion 572 of the lid member 57. As a result, the edge cut valve unit 2 can ensure the sealing property by the O-ring 82.

In the above description, the hot water supply pipe 206 is an example of the "pipeline" of the present invention. The flow path 95 is an example of the "main flow path" of the present invention. The opening 60 is an example of the “upstream opening” of the present invention, and the opening 59 is an example of the “downstream opening” of the present invention. The flow path 97 is an example of the “branch path” of the present invention. The third casing 5 is an example of the "casing" of the present invention. The upper lateral portion 51 is an example of the "cylindrical portion" of the present invention. The annular support portion 263 is an example of the "first support portion" of the present invention. The rear body portion 25 is an example of the “body portion” of the present invention. The annular support portion 273 is an example of the "second support portion" of the present invention. The protrusion 242 is an example of the "fitting portion" of the present invention, and the fitting groove 516 is an example of the "fitted portion" of the present invention. The tubular portion 572 of the lid member 57 is an example of the "positioning member" of the present invention.

As described above, the water heater 1 of the above embodiment includes the edge cutting valve unit 2 in the hot water supply pipe 206 connecting the hot water supply circuit 11 and the circulation heating circuit 12. The edge cut valve unit 2 prevents the backflow of hot water from the circulation heating circuit 12 side to the hot water supply circuit 11 side. The edge cut valve unit 2 includes a third casing 5 and a check valve unit 20. The third casing 5 includes a flow path 95, a flow path 97, and a first valve seat 515. The flow path 95 extends linearly from the opening 60 on the upstream side in the direction in which hot water flows toward the opening 59. The flow path 97 is branched from a branch portion 951 provided in the flow path 95. The edge cutting valve 73 is provided in the flow path 97. The edge cutting valve 73 is constantly urged in the valve opening direction by a spring force, receives back pressure from the hot water supply circuit 11, and is urged in the valve closing direction against the spring force. A first valve seat 515 is provided on the peripheral edge of the opening 60. The third casing 5 includes a cylindrical upper lateral portion 51. The flow path 95 is formed in the upper lateral portion 51. The check valve unit 20 supports the first check valve 70 and the second check valve 71. The first check valve 70 is brought into contact with and separated from the first valve seat 515 to prevent backflow of hot water from the circulation heating circuit 12 side. The second check valve 71 is arranged on the downstream side of the first check valve 70 to prevent backflow of hot water from the circulation heating circuit 12 side. The check valve unit 20 is inserted into the flow path 95 from the opening 59 so that the first check valve 70 faces the first valve seat 515 and can be brought into contact with and detached from the first valve seat 515, and is arranged in the upper lateral portion 51. Will be done.

The check valve unit 20 includes a first member 21 and a second member 22. The second member 22 is arranged on the downstream side of the first member 21. The first member 21 is formed in a cylindrical shape. The first member 21 includes an annular support portion 263, three erection portions 262, a second valve seat 241 and a communication port 251. The annular support portion 263 is provided on the upstream side of the first member 21 and supports the first check valve 70. The three erection portions 262 extend in the axial direction from three locations separated from each other in the circumferential direction on the inner wall portion of the first member 21, and support the annular support portion 263 on the axial center of the first member 21. The second valve seat 241 is provided on the downstream side of the annular support portion 263 and is in contact with and separated from the second check valve 71. The communication port 251 is provided in the rear body portion 25 between the annular support portion 263 and the second valve seat 241 to communicate the flow path 97 with the first member 21. The second member 22 supports the annular support portion 273.

In the check valve unit 20, the second valve seat 241 is located closer to the annular support portion 263 than the flow path 97, and the three erection portions 262 are located closer to the first valve seat 515 than the flow path 97. The second valve seat 241 and the three erection portions 262 are supported by the inner wall portion of the upper lateral portion 51.

Since the three erection portions 262 are located on the upstream side of the flow path 97, the distance between the annular support portion 263 and the first valve seat 515 is shortened. As a result, the advance / retreat stroke of the first check valve 70 is shortened, so that the axis deviation of the first check valve 70 can be prevented. Therefore, the water heater 1 can maintain the close contact with the first valve seat 515 in the closed state of the first check valve 70 in the edge cut valve unit 2.

The present invention is not limited to the above embodiment, and various modifications can be made. In the edge cutting valve unit 2, the flow path 95 and the flow path 96 are provided in parallel in the vertical direction, but may be provided in parallel, for example, in parallel in the horizontal direction (horizontal direction).

The edge cut valve unit 2 includes four casings 3 to 6 and is configured to be fixed to each other with screws 301 to 305, but the number of casings and the fixing method can be freely changed. Further, the opening directions of the connection port 35, the hot water supply connection port 36, the connection port 58, the drain pipe 632, and the inflow pipe 633 are not limited to the above-described embodiment, and can be freely changed.

The flow path 97 of the edge cut valve unit 2 is provided along the vertical direction, but as long as it extends downward, it may be slanted in whole or partially, or it may be bent.

In the first member 21 of the check valve unit 20, the number of erection portions 262 that support the annular support portion 263 is three, but the number of erection portions 262 can be freely changed, preferably three or more.

In the valve support portion 26, the connecting portion 261 may be omitted. In that case, the outer end portions of the plurality of erection portions 262 may be brought into contact with the inner wall portions of the upper lateral direction portion 51.

Regarding the method of attaching the check valve unit 20 to the upper lateral portion 51, in the above embodiment, the first member 21 and the second member 22 are first combined and then inserted and arranged in the upper lateral portion 51. However, the first member 21 may be inserted into the upper lateral portion 51 first, and then the second member 22 may be inserted into the upper lateral portion 51 for arrangement.

1 Water heater 2 Edge cut valve unit 5 3rd casing 11 Hot water supply circuit 12 Circulation heating circuit 20 Check valve unit 21 1st member 22 2nd member 25 Rear body 51 Upper lateral part 57 Lid member 59 Opening 60 Opening 70 1st check valve 71 2nd check valve 73 Edge cut valve 82 O-ring 95,97 Flow path 206 Hot water supply pipe 241 2nd valve seat 242 Protrusion part 261 Connecting part 262 Elevation part 263 Circular support part 274 Cylindrical part 511 Small diameter part 512 Medium diameter part 513 Large diameter part 515 First valve seat 516 Fitting groove 519 Step part 572 Cylindrical part

Claims (4)

In a water heater provided with an edge-cutting valve unit for preventing backflow of hot water from the circulation heating circuit side to the hot water supply circuit side in a pipeline connecting the hot water supply circuit and the circulation heating circuit.
The edge cut valve unit is
A main flow path that extends linearly from the upstream opening in the direction of hot water flow to the downstream opening,
It is branched from the branch portion provided in the main flow path, is always urged in the valve opening direction by a spring force, and is urged in the valve closing direction against the spring force by receiving the back pressure from the hot water supply circuit. A branch road with a margin valve and
A casing provided with the main flow path and the branch path, and a first valve seat provided at the peripheral edge of the upstream opening.
A cylindrical cylindrical portion provided in the casing and having the main flow path formed inside, and a cylindrical portion.
A first check valve that is in contact with and separated from the first valve seat to prevent backflow of hot water from the circulation heating circuit side, and a first check valve that is arranged downstream of the first check valve and from the circulation heating circuit side. It supports a second check valve that prevents backflow of hot water, and is inserted into the main flow path from the downstream opening so that the first check valve faces the first valve seat and can be contacted and separated. It is provided with a check valve unit which is arranged in the cylindrical portion.
The check valve unit includes a first member and a second member arranged on the downstream side of the first member.
The first member is formed in a cylindrical shape.
A first support portion provided on the upstream side and supporting the first check valve,
A plurality of erection portions extending in the axial direction from positions separated from each other in the circumferential direction on the inner wall portion of the first member and supporting the first support portion on the axial center of the first member.
A second valve seat provided on the downstream side of the first support portion and in contact with and separated from the second check valve.
It is provided on the body portion between the first support portion and the second valve seat, and is provided with a communication port for communicating the branch path and the first member.
The second member includes a second support portion that supports the second check valve.
In the check valve unit, the second valve seat is located closer to the second support portion than the branch passage, and the plurality of erection portions are located closer to the first valve seat side than the branch passage. A water heater characterized in that the second valve seat and the plurality of erection portions are supported by an inner wall portion of the cylindrical portion. The first member includes an annular connecting portion that connects with the plurality of erection portions.
The hot water supply according to claim 1, wherein the connecting portion is in close contact with an inner wall portion on the upstream side of the branch path in the cylindrical portion in a state where the check valve unit is arranged in the cylindrical portion. vessel. The inner wall portion of the cylindrical portion is fitted with a fitting portion provided on the check valve unit to restrict the check valve unit from rotating in the circumferential direction with respect to the casing. The water heater according to claim 1 or 2, wherein the portion is provided. The cylindrical part is
A cylindrical small-diameter portion in which the first member is arranged inside,
A cylindrical large-diameter portion provided on the downstream side of the small-diameter portion and having a larger diameter than the small-diameter portion,
A cylindrical medium-diameter portion provided between the small-diameter portion and the large-diameter portion is provided.
Inside the cylindrical portion, between the large diameter portion and the medium diameter portion, a step portion whose diameter is reduced inward in the radial direction is provided.
The fitting portion is a protrusion that protrudes radially outward from the outer peripheral portion of the first member and extends parallel to the axial direction of the first member.
The fitted portion is a notch or groove provided in the middle diameter portion, extending from the step portion in the middle diameter portion in parallel with the axial direction of the casing, and fitting with the fitting portion. hand,
The second member is formed along the inner wall portion of the large-diameter portion in a state of being arranged in the cylindrical portion, and the downstream end portion thereof extends to the downstream side of the medium-diameter portion. Prepare,
An O-ring is arranged on the downstream side of the tubular portion.
A cylindrical positioning member is inserted and fixed to the peripheral edge of the downstream opening of the casing.
The O-ring is
3. The third aspect of the present invention is that the tubular portion is sandwiched between the downstream end portion and the positioning member from the upstream side and the downstream side along the inner wall portion of the downstream side opening. The water heater described in.

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