Pump, and electric water heater system

Abstract

To provide a pump that is easy to maintain, and an electric water heater system.SOLUTION: A pump 10 comprises: a water side impeller 13; a hot water side impeller 14; a hot water side flow passage 12A in which a hot water side inflow port 12B and a hot water side outlet 12C for hot water H are formed while the water side impeller 13 and the hot water side impeller 14 are separately arranged; a water side flow passage 11A in which a water side inflow port 11B and a water side outlet 11C for water W are formed; a rotating shaft 16 for rotating the water side impeller 13 and the hot water side impeller 14; and a motor 15 for rotating the rotating shaft 16. The hot water side flow passage 12A and the water side flow passage 11A are arranged in a line along the rotating shaft 16. The motor 15 is arranged at an end of the hot water side flow passage 12A and the water side flow passage 11A arranged in the line.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to pumps and electric water heater systems. [Background technology]

[0002] Patent Document 1 discloses a configuration of a water heater in which impellers provided in a branch water supply passage and a branch hot water outlet passage are rotated by a single motor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Utility Model Application Publication No. 56-65309 Summary of the Invention [Problem to be solved by the invention]

[0004] In the configuration of Patent Document 1, the branch water supply passage and the branch hot water outlet passage are arranged on either side of the motor, which raises concerns that maintenance such as removing the motor may become difficult.

[0005] The present disclosure has been made in consideration of the above-described conventional situation, and an object of the present disclosure is to provide a pump and an electric water heater system that are easy to maintain. [Means for solving the problem]

[0006] The pump of the first disclosure comprises a plurality of impellers, a plurality of fluid flow paths each having a fluid inlet and outlet, each of the impellers being arranged separately, a rotary shaft for rotating each of the impellers, and a motor for rotating the rotary shaft, wherein the plurality of fluid flow paths are aligned in a row along the rotary shaft, and the motor is arranged at the end of the aligned fluid flow paths.

[0007] The electric water heater system of the second disclosure includes the pump of the first disclosure and an electric water heater, and further includes a plurality of cases each having one fluid flow path formed therein, the plurality of cases being a water-side case provided midway through the flow path through which water flows and a hot water-side case provided midway through the flow path through which hot water flows, the inlet of the hot water-side case being connected to an upstream hot water supply path connected to the secondary side of a heating unit that heats water, the outlet of the hot water-side case being connected to a downstream hot water supply path connected to a discharge unit, the inlet of the water-side case being connected to an upstream water supply path connected to the primary side of the heating unit, and the outlet of the water-side case being connected to a downstream water path connected to the discharge unit. The electric water heater has the heating unit. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic diagram showing the configuration of an electric water heater system according to a first embodiment. [Figure 2] 1 is a side cross-sectional view showing a pump according to a first embodiment. [Figure 3] FIG. 2 is a perspective view showing a cold water side impeller and a hot water side impeller. [Figure 4] 10 is a flowchart showing an example of control in a control unit. [Figure 5] 10 is a flowchart illustrating an example of power supply start control in a control unit. [Figure 6] FIG. 10 is a side cross-sectional view showing a pump according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] First, embodiments of the present disclosure will be listed and described. Any combination of the following embodiments without causing any contradiction is also included in the embodiments for carrying out the invention.

[0010] The pump of the first disclosure comprises: [1] A water cooler includes a plurality of impellers, a plurality of fluid flow paths each having a fluid inlet and an outlet, a rotary shaft for rotating each of the impellers, and a motor for rotating the rotary shaft, the plurality of fluid flow paths being aligned in a line along the rotary shaft, and the motor being positioned at an end of the aligned fluid flow paths. With this configuration, the motor is positioned at the end of the aligned hot water flow path and cold water flow path, making it easy to perform maintenance such as removing the motor.

[0011] [2] The pump described in [1] above further includes a plurality of cases, each of which has one fluid flow path formed therein. This configuration allows for more advanced maintenance, such as separating the hot water side case from the cold water side case.

[0012] [3] In the pump according to any one of [1] to [2] above, one of the cases is a water-side case located in the flow path through which water flows, and the motor is adjacent to the water-side case. With this configuration, when the motor heats up due to the supply of current, the water flowing through the water-side case can be expected to cool the motor.

[0013] [4] In the pump according to any one of [1] to [3] above, the motor has a motor body, a control unit that controls the motor body, and a waterproof housing that houses the control unit. With this configuration, the housing can protect the motor body and the control unit from water damage.

[0014] [5] In the pump described in [4] above, when starting power supply to the motor body, the control unit executes power supply start control to gradually increase the magnitude of the current supplied to the motor body. With this configuration, for example, in a configuration in which an impeller is provided with a torque limiter, it is possible to start rotation of the impeller while preventing the torque limiter from cutting off the transmission of rotational force from the rotating shaft to the impeller.

[0015] [6] In the pump according to any one of [1] to [5] above, each of the impellers is connected to the rotating shaft via a torque limiter. With this configuration, when the rotational resistance of at least one of the impellers increases, the torque limiter can prevent the rotational resistance from interfering with the rotation of the rotating shaft.

[0016] [7] The pump according to any one of [1] to [6] above, further comprising a seal member disposed between the adjacently arranged cases, in contact with the outer peripheral surface of the rotary shaft over the entire circumferential direction, to prevent the fluid from flowing between the cases. This configuration reduces the pressure difference between the two sides of the seal member, thereby requiring only a relatively small amount of compression of the seal member and minimizing the frictional force of the seal member against the rotary shaft.

[0017] [8] In the pump described in [2] above and any of [3] to [7] that directly or indirectly cite [2] above, the multiple cases are a cold water case provided in the flow path through which water flows and a hot water case provided in the flow path through which hot water flows, the inlet of the hot water case is connected to an upstream hot water supply passage connected to the secondary side of a heating section that heats water, the outlet of the hot water case is connected to a downstream hot water supply passage connected to a discharge section, the inlet of the cold water case is connected to an upstream water supply passage connected to the primary side of the heating section, and the outlet of the cold water case is connected to a downstream water supply passage connected to the discharge section. With this configuration, the pump can be attached to the primary side of the discharge section, making it easier to attach and detach the discharge section and the pump, and ultimately easier to perform maintenance.

[0018] [9] In the pump according to any one of [1] to [8] above, the motor has a magnet that rotates together with the rotating shaft and a holder that holds the magnet and connects it to the rotating shaft, and among the multiple impellers, some of the impellers are integrally mounted on the holder, and the remaining impellers are connected to the rotating shaft. With this configuration, even if the rotating shaft breaks, the torque of the motor can be transmitted to the impellers that are integrally mounted on the holder, thereby avoiding a situation in which the supply of fluid is completely cut off.

[0019] The electric water heater system of the second disclosure is [8] and an electric water heater having the heating unit. According to this configuration, the primary side of the pump is connected to the flow path that discharges hot and cold water from the electric water heater, so it is possible to retrofit the pump to an existing electric water heater, making it easy to handle as a system.

[0020] <Embodiment 1> Hereinafter, a first embodiment of an electric water heater system 100 and a pump 10 of the present disclosure will be described with reference to FIGS. 1 to 5. FIG.

[0021] As shown in FIG. 1, the electric water heater system 100 is used by being connected to a discharge unit 70 provided in, for example, a washbasin (not shown). The electric water heater system 100 includes an electric water heater 50 and a pump 10. The electric water heater system 100 heats at least a portion of water W, which is a fluid that flows into the electric water heater 50, to hot water H, and then uses the pump 10 to increase the flow of the hot water H or cold water W, which is a fluid that flows out of the electric water heater 50, and then transports the hot water H or cold water W to the discharge unit 70. For example, when a hot and cold water mixing valve 70A provided in the discharge unit 70 is opened to start discharging at least one of the hot water H and cold water W from a discharge port 70D, the pump 10 starts operating upon detecting the flow of hot water H in a hot water supply pipe 70B, which is a hot water supply path downstream of the discharge unit 70, or the flow of water in a water supply pipe 70C, which is a water supply path downstream of the discharge unit 70, and thereby amplifies the flow of the hot water H or cold water W toward the discharge unit 70.

[0022] [Electric water heater configuration] As shown in FIG. 1, the electric water heater 50 has a tank 51 serving as a heating unit, a water pipe 52 serving as an upstream water supply line, and a hot water pipe 53 serving as an upstream hot water supply line. The tank 51 is configured as a hollow container body and stores the water W that flows in. A known heater (not shown) that generates heat when electricity is applied is provided inside the tank 51. For example, a sheath heater or the like is used as the heater. The water W that flows in is heated in the tank 51. An inlet 54 for allowing the water W to flow in from the water pipe 52 is formed near the bottom of the tank 51, and an outlet 55 for allowing the hot water H boiled in the tank 51 to flow out is formed near the ceiling. In other words, the water pipe 52 is connected to the primary side of the tank 51.

[0023] Water W flows into water pipe 52 via inlet 56. Pressure reducing valve 57 is provided midway along water pipe 52. Pressure reducing valve 57 functions to reduce the water pressure of water W flowing in from inlet 56 to a predetermined level or lower. Specifically, pressure reducing valve 57 adjusts the water pressure in water pipe 52 and hot water pipe 53 to a predetermined level that is lower than the water pressure upstream of inlet 56. Water W that flows into water pipe 52 flows out of electric water heater 50 as is, or flows into tank 51 via inlet 54.

[0024] The hot water pipe 53 is connected to the outlet 55 of the tank 51 and extends to the outside of the electric water heater 50. Hot water H boiled in the tank 51 flows into the hot water pipe 53. The hot water H that flows into the hot water pipe 53 flows out of the electric water heater 50.

[0025] [Pump configuration] As shown in Figure 2, the pump 10 includes multiple cases, namely a water side case 11 and a hot water side case 12, multiple fluid flow paths, namely a water side flow path 11A and a hot water side flow path 12A, multiple impellers, namely a water side impeller 13 and a hot water side impeller 14, multiple torque limiters 17, a motor 15, and a rotating shaft 16.

[0026] The water side case 11 is disposed midway through the flow path through which water W flows. The water side case 11 is made of, for example, synthetic resin. The water side flow path 11A is the flow path through which water W passes, and is formed inside the water side case 11. The water side flow path 11A has a water side inlet 11B which is an inlet, and a water side outlet 11C which is an outlet. The water side inlet 11B is formed at one end of the water side flow path 11A. Water W flows into the water side flow path 11A through the water side inlet 11B. The water side outlet 11C is formed at the other end of the water side flow path 11A. The water W that flows into the water side flow path 11A flows out through the water side outlet 11C.

[0027] Water side inlet 11B and water side outlet 11C are formed in water side case 11. Water pipe 52 is connected to water side inlet 11B. For example, water side inlet 11B and water pipe 52 are connected using a known quick fastener (not shown) while sealing with an O-ring (not shown). Water side outlet 11C is connected to water supply pipe 70C, which is connected to discharge portion 70. For example, water side outlet 11C and water supply pipe 70C are connected using a known quick fastener (not shown) while sealing with an O-ring (not shown).

[0028] A water-side flow sensor 11E is provided in the water-side flow path 11A near the water-side outlet 11C. For example, the water-side flow sensor 11E is configured to output a water flow signal F1, which is a voltage signal corresponding to the degree of flow of water W from the water-side flow path 11A toward the water supply pipe 70C. For example, the water flow signal F1 increases in magnitude as the degree of flow of water W increases, and decreases in magnitude as the degree of flow of water W decreases. For example, when the water-side flow sensor 11E does not detect the flow of water W, or when water W flows into the water-side flow path 11A from the water-side outlet 11C, it outputs a water flow signal F1 with a magnitude corresponding to a state in which water W is not flowing (for example, 0 V).

[0029] The hot water side case 12 is arranged midway through the flow path through which the hot water H flows. The hot water side case 12 is made of, for example, synthetic resin. The hot water side flow path 12A is a flow path through which the hot water H passes, and is formed inside the hot water side case 12. The hot water side flow path 12A has a hot water side inlet 12B which is an inlet, and a hot water side outlet 12C which is an outlet. The hot water side inlet 12B is formed at one end of the hot water side flow path 12A. The hot water H flows into the hot water side flow path 12A through the hot water side inlet 12B. The hot water side outlet 12C is formed at the other end of the hot water side flow path 12A. The hot water H that flows into the hot water side flow path 12A flows out through the hot water side outlet 12C.

[0030] The hot water side inlet 12B and the hot water side outlet 12C are formed in the hot water side case 12. A hot water pipe 53, which is connected to the secondary side (downstream side) of the tank 51, is connected to the hot water side inlet 12B. For example, the hot water side inlet 12B and the hot water pipe 53 are connected using a known quick fastener (not shown) while sealing with an O-ring (not shown). A hot water supply pipe 70B, which is connected to the discharge part 70, is connected to the hot water side outlet 12C. For example, the hot water side outlet 12C and the hot water supply pipe 70B are connected using a known quick fastener (not shown) while sealing with an O-ring (not shown).

[0031] A hot water side flow sensor 12E is provided near the hot water side outlet 12C in the hot water side flow path 12A. For example, the hot water side flow sensor 12E is configured to output a hot water flow signal F2, which is a voltage signal corresponding to the degree of flow of hot water H from the hot water side flow path 12A toward the hot water supply pipe 70B. For example, the hot water flow signal F2 increases in magnitude as the degree of flow of hot water H increases, and decreases in magnitude as the degree of flow of hot water H decreases. For example, when the hot water side flow sensor 12E does not detect the flow of hot water H, or when hot water H flows from the hot water supply pipe 70B toward the hot water side flow path 12A, it outputs a hot water flow signal F2 with a magnitude (e.g., 0 V) ​​corresponding to a state in which hot water H is not flowing.

[0032] A closure member 20 is attached to the hot water side case 12 so as to cover the hot water side flow path 12A. A circular hot water side seal member 21 is sandwiched between the hot water side case 12 and the closure member 20. The hot water side seal member 21 seals the gap between the hot water side case 12 and the closure member 20 so that the hot water side flow path 12A does not communicate with the outside space.

[0033] The water side case 11 and the hot water side case 12 are arranged adjacent to each other in a row. A communication passage 11D is formed through the adjacent walls of the water side case 11 and the hot water side case 12, connecting the water side flow path 11A and the hot water side flow path 12A. A first seal member 18, which is an annular seal member, is arranged coaxially with the communication passage 11D. The first seal member 18 is arranged between the water side case 11 and the hot water side case 12, which are arranged side by side. A rotating shaft 16, described below, is inserted through the communication passage 11D. The first seal member 18 contacts the outer peripheral surface of the rotating shaft 16 inserted through the communication passage 11D and the inner peripheral surface of the communication passage 11D. In this way, the first seal member 18 prevents hot water H and cold water W from flowing between the water side case 11 and the hot water side case 12. The inner diameter of the first seal member 18 is slightly smaller than the outer diameter of the rotary shaft 16, and is set to, for example, 10 mm or less.

[0034] An annular second seal member 19 is disposed between the adjacent walls of the water side case 11 and the hot water side case 12. The second seal member 19 is disposed to surround the communicating passage 11D while being spaced apart from the communicating passage 11D. The second seal member 19 contacts the wall surfaces of the adjacent walls of the water side case 11 and the hot water side case 12.

[0035] As shown in FIG. 3, water side impeller 13 and hot water side impeller 14 are circular and hollow. An inlet 13A is formed at one axial end of water side impeller 13. The other end of water side impeller 13 is covered by a closing wall 13D. A discharge port 13C is formed on the outer circumferential surface of the other end of water side impeller 13, and is partitioned circumferentially by a plurality of blades 13B extending radially from the axis. When water side impeller 13 is viewed from the inlet 13A side, each blade 13B extends radially and is curved to bulge counterclockwise. Water side impeller 13 is disposed in water side flow path 11A of water side case 11, with inlet 13A facing water side inlet 11B and discharge port 13C facing water side outlet 11C (see FIG. 2).

[0036] An inlet 14A is formed at one axial end of the hot water side impeller 14. The other axial end of the hot water side impeller 14 is covered by a closing wall 14D. A discharge port 14C is formed on the outer peripheral surface of the other axial end of the hot water side impeller 14, and is partitioned circumferentially by multiple blades 14B extending radially from the axis. When the hot water side impeller 14 is viewed from the inlet 14A side, each blade 14B extends radially and is curved so as to bulge clockwise. The hot water side impeller 14 is disposed in the hot water side flow path 12A of the hot water side case 12, with the inlet 14A facing the hot water side inlet 12B and the discharge port 14C facing the hot water side outlet 12C (see FIG. 2). That is, the cold water side impeller 13 and the hot water side impeller 14 are disposed separately in the cold water side flow path 11A and the hot water side flow path 12A. In other words, the water side case 11 and the hot water side case 12 house the water side impeller 13 and the hot water side impeller 14 separately.

[0037] The water side impeller 13 and the hot water side impeller 14 are configured to be mirror symmetrical (see Figure 3). The water side impeller 13 arranged in the water side flow path 11A and the hot water side impeller 14 arranged in the hot water side flow path 12A are arranged coaxially with their inlets 13A, 14A facing each other (see Figure 2).

[0038] The torque limiter 17 may be of a known type, such as a magnet type or a friction type. The torque limiter 17 is, for example, cylindrical. As shown in FIG. 2 , one torque limiter 17 is connected to each of the water side impeller 13 and the hot water side impeller 14. Specifically, one torque limiter 17 is coaxial with the water side impeller 13 and connected to the closure wall 13D. The other torque limiter 17 is coaxial with the hot water side impeller 14 and connected to the closure wall 14D. The two torque limiters 17 are arranged on opposite sides of the water side impeller 13 and the hot water side impeller 14.

[0039] The motor 15 has a motor body 15A, a cover 15B that serves as a storage section, and a control section 15C. The motor body 15A may be, for example, a known DC motor. The motor body 15A stores a rotor 15D. The rotor 15D rotates due to a magnetic field generated by passing a current through the motor body 15A. The cover 15B is made of, for example, synthetic resin and is disposed so as to cover the motor body 15A. The cover 15B is waterproofed. The motor body 15A covered by the cover 15B does not allow water to enter from the outside.

[0040] The control unit 15C is configured, for example, by mounting a CPU and memory on a circuit board. The control unit 15C is housed in the cover 15B together with the motor main body 15A. This prevents water from entering and adhering to the control unit 15C from the outside.

[0041] The control unit 15C has a function of controlling the operation of the motor main body 15A. For example, the control unit 15C controls the operation of the motor main body 15A by PWM (Pulse Width Modulation) control. Specifically, the control unit 15C changes the duty (the ratio of the on time to the period) of the PWM signal to change the rotation speed (rpm) of the rotor 15D.

[0042] The control unit 15C is configured to receive a water flow signal F1 from the cold water flow sensor 11E and a hot water flow signal F2 from the hot water flow sensor 12E. For example, when the hot and cold water mixing valve 70A of the discharge unit 70 is opened, the discharge of at least one of hot water H and cold water W begins due to the water pressure adjusted to a predetermined level by the pressure reducing valve 57 of the electric water heater 50. When the water W is discharged, a water flow signal F1 corresponding to the degree of flow is output to the control unit 15C. When the hot water H is discharged, a hot water flow signal F2 corresponding to the degree of flow is output to the control unit 15C. When at least one of the water flow signal F1 and the hot water flow signal F2 exceeds a flow threshold, the control unit 15C starts supplying current to the motor main body 15A and starts rotating the rotor 15D.

[0043] Here, the flow threshold is stored, for example, in a memory possessed by the control unit 15C and is set to a value greater than 0 V, for example, a value less than 50% of the maximum value that the water flow signal F1 and the hot water flow signal F2 can assume. When the hot and cold water mixing valve 70A of the discharge unit 70 is closed, the water flow signal F1 from the water-side flow sensor 11E and the hot water flow signal F2 from the hot water-side flow sensor 12E become smaller than the flow threshold. Then, the control unit 15C stops supplying current to the motor main body 15A.

[0044] For example, if the water pipe 52 is incorrectly connected to the water outlet 11C, or the hot water pipe 53 is incorrectly connected to the hot water outlet 12C, and hot water H flows through the hot water flow path 12A, or if the water W flows through the water outlet 11A, the hot water flow sensor 12E outputs a hot water flow signal F2 with a magnitude (e.g., 0 V) ​​corresponding to a state in which hot water H is not flowing, and the water flow sensor 11E outputs a water flow signal F1 with a magnitude (e.g., 0 V) ​​corresponding to a state in which water W is not flowing. In other words, the water flow sensors 11E and 12E have the function of preventing the pump 10 from operating if the pump 10 is connected to the electric water heater 50 in the wrong orientation, thereby preventing operation in the event of incorrect assembly. Also, a configuration may be provided in which a check valve is provided in either the water inlet 11B or the water outlet 11C and either the hot water inlet 12B or the hot water outlet 12C. This allows the discharge of hot water H and cold water W to be suppressed in the event of incorrect assembly, allowing the installer to understand that the assembly has been incorrect.

[0045] As shown in Figure 2, motor 15 is located at the end of cold water side flow path 11A and hot water side flow path 12A, which are aligned in a row. In other words, motor 15 is located at the end of cold water side case 11 and hot water side case 12, which are aligned in a row. Specifically, motor 15 is attached to water side case 11 so as to cover cold water side flow path 11A. A circular water side seal member 22 is sandwiched between water side case 11 and motor 15. Water side seal member 22 seals the gap between water side case 11 and motor 15 so as to prevent communication between cold water side flow path 11A and the outside space.

[0046] The rotating shaft 16 is made of, for example, metal and is formed to extend long in one direction. One end of the rotating shaft 16 penetrates the rotor 15D of the motor 15, and the other end protrudes from the motor 15. When current is supplied to the motor main body 15A, the rotating shaft 16 rotates integrally with the rotor 15D. In other words, the motor 15 rotates the rotating shaft 16 via the rotor 15D. The outer diameter of the rotating shaft 16 is set to, for example, 10 mm or less.

[0047] The rotating shaft 16 is disposed so as to penetrate the cold water side flow path 11A of the cold water side case 11 and the hot water side flow path 12A of the hot water side case 12. Specifically, the rotating shaft 16 is inserted through the communicating passage 11D and is disposed so as to penetrate two torque limiters 17, the cold water side impeller 13, and the hot water side impeller 14. The cold water side flow path 11A and the hot water side flow path 12A can be said to be aligned in a line along the rotating shaft 16. In other words, the cold water side case 11 and the hot water side case 12 can be said to be aligned in a line along the rotating shaft 16. The inner peripheral edge of the first seal member 18 contacts the entire outer peripheral surface of the rotating shaft 16 in the communicating passage 11D. Generally, the greater the pressure difference between one side and the other side of the seal member (for example, one side is the cold water side flow path and the other side is the atmosphere), the greater the amount of compression of the seal member must be to improve the watertight effect of the seal member. However, in this embodiment, the water pressure of the cold water W in the cold water side flow path 11A and the water pressure of the hot water H in the hot water side flow path 12A are substantially the same. Therefore, the amount of squeezing of the first seal member 18 is relatively small. This makes it possible to reduce the frictional force of the first seal member 18 between the rotating shaft 16 and the motor 15, and ultimately reduces the load on the motor 15.

[0048] Rotating shaft 16 is connected to each torque limiter 17, but is not connected to water side impeller 13 or hot water side impeller 14. In other words, water side impeller 13 and hot water side impeller 14 are connected to rotating shaft 16 via torque limiters 17. When rotating shaft 16 rotates together with rotor 15D, the rotational force of rotating shaft 16 is transmitted to water side impeller 13 and hot water side impeller 14 via each torque limiter 17. In this way, when rotating shaft 16 rotates together with rotor 15D, each torque limiter 17, water side impeller 13, and hot water side impeller 14 also rotate together with rotating shaft 16.

[0049] For example, when only water W is being discharged from the discharge portion 70, current is supplied to the motor main body 15A based on the water flow signal F1, causing the rotor 15D and the rotating shaft 16 to rotate, and the cold water side impeller 13 and the hot water side impeller 14 to rotate accordingly. Because the hot water side impeller 14 rotates even when hot water H is not being discharged from the discharge portion 70, the rotational resistance force generated in the hot water side impeller 14 is greater than when hot water H is being discharged. Here, the rotational resistance force refers to a force that acts to impede the rotation of the rotating shaft 16. When this rotational resistance force exceeds a predetermined magnitude, the torque limiter 17 connected to the hot water side impeller 14 cuts off the transmission of rotational force from the rotating shaft 16 to the hot water side impeller 14. This prevents the rotational resistance force generated in the hot water side impeller 14 from interfering with the rotation of the rotating shaft 16 caused by the motor main body 15A.

[0050] Furthermore, when only hot water H is being discharged from discharge portion 70, current is supplied to motor main body 15A based on hot water flow signal F2, causing rotor 15D and rotating shaft 16 to rotate, and thus cold water side impeller 13 and hot water side impeller 14 to rotate. Because water side impeller 13 rotates even when water W is not being discharged from discharge portion 70, the rotational resistance force generated in water side impeller 13 is greater than when water W is being discharged. When this rotational resistance force exceeds a predetermined magnitude, torque limiter 17 connected to water side impeller 13 cuts off the transmission of rotational force from rotating shaft 16 to water side impeller 13. This prevents the rotational resistance force generated in water side impeller 13 from interfering with the rotation of motor main body 15A.

[0051] For example, when the hot and cold water mixing valve 70A of the discharge portion 70 is fully open, the rotational resistance force generated in the cold water side impeller 13 (hot water side impeller 14) is smallest. This rotational resistance force gradually increases as the opening of the hot and cold water mixing valve 70A decreases, and reaches a maximum when the hot and cold water mixing valve 70A is closed. For example, if the opening of the hot and cold water mixing valve 70A is fully open (defined as 100%), the torque limiter 17 is set so that when the rotational resistance force becomes greater than the rotational resistance force generated in the cold water side impeller 13 (hot water side impeller 14) when the opening is 30% (i.e., when the opening is smaller than 30%), the torque limiter 17 will cut off the transmission of rotational force from the rotating shaft 16 to the cold water side impeller 13 (hot water side impeller 14).

[0052] [An example of controlling the motor body by the control unit] Next, an example of the control of the motor main body 15A by the control unit 15C will be described with reference to FIGS. 4 and 5. For example, the control unit 15C is configured to repeatedly execute the control shown in FIGS. 4 and 5. First, in step S1, the control unit 15C determines whether at least one of the hot water H and the cold water W is flowing. Specifically, the control unit 15C determines whether either the water flow signal F1 from the cold water flow sensor 11E or the hot water flow signal F2 from the hot water flow sensor 12E is equal to or greater than the flow threshold. If the control unit 15C determines in step S1 that neither the hot water H nor the cold water W is flowing (i.e., the water flow signal F1 and the hot water flow signal F2 are less than the flow threshold) (No in step S1), the control unit 15C proceeds to step S2, where the magnitude of the current value supplied to the motor main body 15A is set to 0 (A). Then, the control unit 15C proceeds to step S3, where the current fixation flag is set to 0, the process shown in FIG. 4 is terminated, and the process shown in FIG. 4 is repeated again. For example, the current fixation flag is configured as part of the RAM in the control unit 15C.

[0053] In step S1, when the control unit 15C determines that at least one of the hot water H and the cold water W is flowing (Yes in step S1, and at least one of the water flow signal F1 and the hot water flow signal F2 is equal to or greater than the flow threshold), the process proceeds to step S4. In step S4, the control unit 15C determines whether the current fixed flag is 0. In step S4, when the control unit 15C determines that the current fixed flag is not 0 (No in step S4, and the current fixed flag is 1), the process shown in FIG. 4 is terminated, and the process shown in FIG. 4 is repeated again.

[0054] If the control unit 15C determines in step S4 that the current fixation flag is 0 (Yes in step S4), the process proceeds to step S5. In step S5, the control unit 15C executes power supply start control. The power supply start control is control for gradually increasing the magnitude of the current supplied to the motor main body 15A when starting power supply to the motor main body 15A. The power supply start control will be described with reference to FIG. 5. First, in step S51, the control unit 15C determines whether the magnitude of the current supplied to the motor main body 15A exceeds a current threshold. For example, the current threshold is stored in a memory included in the control unit 15C. In step S51, if the control unit 15C determines that the magnitude of the current supplied to the motor main body 15A is equal to or less than the current threshold (No in step S51), the process proceeds to step S52. In step S52, the control unit 15C increases the magnitude of the current supplied to the motor main body 15A by a predetermined amount and executes S51 again. For example, in step S52, the control unit 15C performs control to increase the duty by a predetermined rate.

[0055] In this way, control unit 15C repeatedly executes steps S51 and S52 until the current threshold is exceeded, thereby gradually increasing the value of the current supplied to motor main body 15A in stages. This allows the rotation speed to be gradually increased so that a current greater than the current threshold is not suddenly applied to motor main body 15A, causing a sudden change in the rotation speed of rotating shaft 16, and allows cold water side impeller 13 and hot water side impeller 14 to start rotating without torque limiter 17 cutting off the transmission of rotational force to these impellers.

[0056] In step S51, if control unit 15C determines that the magnitude of the current supplied to motor main body 15A exceeds the current threshold (Yes in step S51), the process proceeds to step S53. In step S53, control unit 15C fixes and maintains the magnitude of the current supplied to motor main body 15A at the current current value (i.e., a current value that is slightly above the current threshold).

[0057] Then, when the process proceeds to step S6 (see Fig. 4), the control unit 15C sets the current fixed flag to 1, terminates the process shown in Fig. 4, and repeats the process shown in Fig. 4. The current fixed flag is a flag indicating that the magnitude of the current value supplied to the motor main body 15A has exceeded the current threshold value, and it is no longer necessary to gradually increase the current value in stages.

[0058] According to the embodiment configured as above, the following effects are achieved.

[0059] Pump 10 of the present disclosure comprises water-side impeller 13 and hot water side impeller 14, hot water side flow path 12A in which water-side impeller 13 and hot water side impeller 14 are arranged separately and which has hot water side inlet 12B and hot water side outlet 12C for hot water H, and water-side flow path 11A which has cold water side inlet 11B and cold water side outlet 11C for cold water W, a rotating shaft 16 that rotates water-side impeller 13 and hot water side impeller 14, and a motor 15 that rotates rotating shaft 16, hot water side flow path 12A and cold water side flow path 11A are aligned along rotating shaft 16, and motor 15 is positioned at the end of the aligned hot water side flow path 12A and cold water side flow path 11A. With this configuration, motor 15 is positioned at the end of the aligned hot water side flow path 12A and cold water side flow path 11A, making maintenance such as removing motor 15 easy to perform.

[0060] The pump 10 of the present disclosure further includes a hot water side case 12 in which a hot water side flow path 12A is formed, and a cold water side case 11 in which a cold water side flow path 11A is formed. This configuration makes it possible to perform more advanced maintenance, such as separating the hot water side case 12 and the cold water side case 11.

[0061] In the pump 10 of the present disclosure, one of the hot water side case 12 and the cold water side case 11 is the cold water side case 11 arranged in the middle of the flow path through which the water W flows, and the motor 15 is adjacent to the cold water side case 11. With this configuration, when the motor 15 heats up due to the supply of current, the water W flowing through the cold water side case 11 can be expected to cool the motor 15.

[0062] In pump 10 of the present disclosure, motor 15 includes motor body 15A, control unit 15C that controls motor body 15A, and waterproof cover 15B that houses control unit 15C. With this configuration, cover 15B can protect motor body 15A and control unit 15C from water damage.

[0063] In pump 10 of the present disclosure, when starting power supply to motor body 15A, control unit 15C executes power supply start control to gradually increase the magnitude of the current supplied to motor body 15A. With this configuration, it is possible to start rotation of cold water side impeller 13 and hot water side impeller 14 without torque limiter 17 interrupting the transmission of rotational force to cold water side impeller 13 and hot water side impeller 14.

[0064] In pump 10 of the present disclosure, water side impeller 13 and hot water side impeller 14 are connected to rotating shaft 16 via torque limiter 17. With this configuration, if the rotational resistance of at least one of water side impeller 13 and hot water side impeller 14 increases, torque limiter 17 can prevent the rotational resistance from interfering with the rotation of rotating shaft 16.

[0065] The pump 10 of the present disclosure is provided with a first seal member 18 that is disposed between the hot water side case 12 and the cold water side case 11 that are arranged side by side, and that contacts the outer peripheral surface of the rotating shaft 16 over the entire circumferential direction, preventing hot water H and cold water W from flowing between the hot water side case 12 and the cold water side case 11. With this configuration, the pressure difference between one side and the other side (hot water H and cold water W) of the first seal member 18 can be reduced, and as a result, the amount of compression of the first seal member 18 can be kept relatively small, making it possible to keep the frictional force of the first seal member 18 against the rotating shaft 16 small.

[0066] In pump 10 of the present disclosure, hot water side case 12 and cold water side case 11 are provided in the flow path through which water W flows, and hot water side case 12 is provided in the flow path through which hot water H flows. Hot water side inlet 12B of hot water side case 12 is connected to hot water pipe 53 connected to the secondary side of tank 51 that heats water W. Hot water side outlet 12C of hot water side case 12 is connected to hot water supply pipe 70B connected to discharge section 70. Water side inlet 11B of water side case 11 is connected to water pipe 52 connected to the primary side of tank 51. Water side outlet 11C of water side case 11 is connected to water supply pipe 70C connected to discharge section 70. This configuration allows pump 10 to be attached to the primary side of discharge section 70, facilitating attachment and detachment of discharge section 70 and pump 10, thereby facilitating maintenance.

[0067] The electric water heater system 100 of the present disclosure includes a pump 10 and an electric water heater 50 having a tank 51. With this configuration, the primary side of the pump 10 is connected to a flow path that discharges hot water H and cold water W from the electric water heater 50, so it is possible to retrofit the pump 10 to an existing electric water heater 50, making it easy to handle as a system.

[0068] <Embodiment 2> Pump 110 provided in electric water heater system 200 according to embodiment 2 differs from embodiment 1 in that rotor 15D has magnet 15E and holder 15F, that cold water side impeller 113 is integral with the holder, that a torque limiter is not provided, and the configuration of hot water side impeller 114. In the following explanation, the same components as those in embodiment 1 are designated by the same reference numerals, and duplicate explanations will be omitted.

[0069] 6, rotor 15D of motor 15 has magnet 15E and holder 15F. For example, magnet 15E is formed in a cylindrical shape, with south poles and north poles alternately arranged in the circumferential direction. Magnet 15E is arranged coaxially with rotation shaft 16.

[0070] Holder 15F is made of, for example, synthetic resin. Holder 15F is formed in a cylindrical shape. A recess 15J is formed on the outer peripheral surface of holder 15F, recessed radially inward. Magnet 15E is fitted into recess 15J. In other words, holder 15F holds magnet 15E by fitting magnet 15E into recess 15J.

[0071] A connecting portion 15G is provided at one axial end of the holder 15F, protruding and extending toward the water-side flow path 11A. The connecting portion 15G is formed in a cylindrical shape. The connecting portion 15G is disposed coaxially with the holder 15F.

[0072] The protruding end of connecting portion 15G is connected to closing wall 13D of water side impeller 113. The configuration of water side impeller 113 is the same as water side impeller 13 in embodiment 1, except that it is connected to the protruding end of connecting portion 15G. Holder 15F, connecting portion 15G, and water side impeller 113 are arranged coaxially. Holder 15F, connecting portion 15G, and water side impeller 113 are integrally molded as a single component.

[0073] Holder 15F, connecting portion 15G, and water-side impeller 113, which are single components, are integrally molded so as to be coaxial with one end of rotating shaft 16. For example, the outer peripheral surface of one end of rotating shaft 16 is formed with a radially concave or convex uneven shape (not shown), and one end of rotating shaft 16 with this uneven shape is placed in a mold that molds holder 15F, connecting portion 15G, and water-side impeller 113 to mold holder 15F, connecting portion 15G, and water-side impeller 113. This allows the synthetic resin to adhere to the outer surface of the concave and convex shape of rotating shaft 16, preventing connecting portion 15G and water-side impeller 113 from spinning freely relative to rotating shaft 16.

[0074] The hot water side impeller 114 is directly connected to the rotating shaft 16. Specifically, the other end of the rotating shaft 16 has a smaller diameter than the one end, forming a so-called stepped shape. The hot water side impeller 114 has a cylindrical portion 114E extending from the closing wall 14D toward the inlet 14A. The other end of the rotating shaft 16 is inserted into the cylindrical portion 114E of the hot water side impeller 114. The diameter of the other end of the rotating shaft 16 and the inner diameter of the cylindrical portion 114E are the same. The inner peripheral surface of the cylindrical portion 114E is in close contact with the outer peripheral surface of the other end of the rotating shaft 16 to prevent idling. A groove 16A is formed at the other end of the rotating shaft 16 at a position protruding from the hot water side impeller 114. A fastener 16B (for example, a known C-ring or E-ring) is fitted into the groove 16A. This prevents the hot water side impeller 114 from falling off from the other end of the rotary shaft 16. Rotational force is transmitted directly to the hot water side impeller 114 from the rotary shaft 16.

[0075] For example, when only water W is being discharged from discharge portion 70, current is supplied to motor main body 15A based on water flow signal F1, and rotor 15D, rotating shaft 16, cold water side impeller 113, and hot water side impeller 114 rotate. Because hot water side impeller 114 rotates even though hot water H is not being discharged from discharge portion 70, a rotational resistance force is generated in hot water side impeller 114. This rotational resistance force is a force that resists the rotational force applied to rotating shaft 16 from motor main body 15A. The rotational resistance force generated in hot water side impeller 114 and the rotational force generated in motor main body 15A act to twist rotating shaft 16.

[0076] At this time, the synthetic resin forming holder 15F, connecting portion 15G, and water-side impeller 113 is molded in close contact with the uneven surface formed on the outer circumferential surface of one end of rotating shaft 16, thereby generating frictional force between the outer circumferential surface of one end of rotating shaft 16 and holder 15F, connecting portion 15G, and water-side impeller 113. As a result, one end of rotating shaft 16 is reinforced by holder 15F, connecting portion 15G, and water-side impeller 113, as if its diameter were increased. Therefore, when the rotational resistance force caused by hot water side impeller 114 and the rotational force generated in motor main body 15A act on rotating shaft 16, they act mainly to twist the protruding portion of rotating shaft 16 that is not covered by holder 15F, connecting portion 15G, and water-side impeller 113 (hereinafter simply referred to as the protruding portion).

[0077] When only hot water H is being discharged from discharge portion 70, current is supplied to motor main body 15A based on hot water flow signal F2, and rotor 15D rotates along with rotating shaft 16, water-side impeller 113, and hot water side impeller 114. Because water-side impeller 113 rotates even though water W is not being discharged from discharge portion 70, a rotational resistance force is generated in water-side impeller 113. This rotational resistance force is a force that resists the rotational force applied to rotating shaft 16 from motor main body 15A. Water-side impeller 113 and hot water side impeller 114 always rotate together with rotating shaft 16.

[0078] The rotational resistance force generated in water-side impeller 113 and the rotational force generated in motor main body 15A act mainly to twist holder 15F, connecting portion 15G, and one end of rotary shaft 16.

[0079] If rotating shaft 16 were to break at a portion (protruding portion) between water side impeller 113 and hot water side impeller 114, the rotational force generated in motor main body 15A would not be transmitted to hot water side impeller 114. Because water side impeller 113 is formed integrally with holder 15F of rotor 15D, the rotational force generated in motor main body 15A is transmitted to water side impeller 113.

[0080] If a break occurs between water side impeller 113 and connecting portion 15G, the rotational force generated in motor main body 15A will not be transmitted to water side impeller 113. In this case, the rotational force generated in motor main body 15A will be transmitted to hot water side impeller 114 via rotating shaft 16.

[0081] Motor 15 has magnet 15E that rotates together with rotating shaft 16, and holder 15F that holds magnet 15E and connects it to rotating shaft 16. Of water side impeller 113 and hot water side impeller 114, water side impeller 113, which is one of the impellers, is integrally provided with holder 15F, and hot water side impeller 114, which is the remaining impeller, is connected to rotating shaft 16. With this configuration, even if rotating shaft 16 were to break, the rotational force of motor 15 can be transmitted to water side impeller 113, which is integrally provided with holder 15F, thereby avoiding a situation in which hot and cold water cannot be supplied at all.

[0082] The present disclosure is not limited to the first and second embodiments described above and illustrated in the drawings, and the following embodiments, for example, are also included within the technical scope of the pump and electric water heater system of the present disclosure.

[0083] (1) Unlike the first embodiment, the configuration may include one case, or may include three or more cases. (2) Unlike the first embodiment, the pump of the present disclosure may be installed in a toilet. In this case, the pump will consist of only one motor and water-side case. (3) Unlike embodiment 1, the connections between the water side inlet and the water pipe, the water side outlet and the water supply pipe, the hot water side inlet and the hot water pipe, and the hot water side outlet and the hot water supply pipe may be made by connecting pipe threads using gaskets or sealing tape. (4) In the case of a design that dispenses only cold water or only hot water, the inlet and outlet of the case that is not being used may be closed with a closing plug or the like, and the pipeline and supply pipe may be connected to the case that is being used. Also, the pump may be connected only to either the hot water or the cold water, whichever has the lower water pressure. (5) Unlike embodiment 1, a known water hammer reduction mechanism for reducing water hammer may be provided between the discharge portion and the pump (between the water side outlet and the water supply pipe, or between the hot water side outlet and the hot water supply pipe). (6) Unlike the first embodiment, two discharge portions may be provided, two water supply pipes may be connected to the cold water outlet, and two hot water supply pipes may be connected to the hot water outlet. (7) Unlike the first embodiment, the water side impeller and the hot water side impeller may have the same shape. That is, the blades of the water side impeller and the hot water side impeller may be curved in the same direction. In this case, the water side impeller and the hot water side impeller are arranged coaxially in the same orientation. (8) Unlike the first embodiment, a check valve may be provided at the cold water outlet and the hot water outlet. This configuration prevents hot water (cold water) from flowing from the high water pressure side to the low water pressure side of the hot and cold water mixing valve at the discharge section. In particular, preventing water from flowing into the hot water side prevents the temperature of the boiled water from dropping. (9) When hot or cold water starts to be discharged from the discharge port, water flows into the case, causing the impeller to rotate. At this time, the rotating shaft also rotates via the torque limiter, causing the motor body to generate electricity. By detecting the current generated by the motor body in this way, the supply of current to the motor body may be started. (10) The threshold value at which the torque limiter cuts off the transmission of rotational force from the rotating shaft to the water side impeller (hot water side impeller) may be set to the magnitude of the rotational resistance force generated in the water side impeller (hot water side impeller) when the hot water / cold water mixing valve is opened to less than 30% of its full opening. (11) A thermal fuse may be provided to prevent overheating due to an overcurrent flowing through the motor body. (12) In a site where the water supply pressure is relatively low, the pump may be connected upstream of the electric water heater so that water flows into the pump. Alternatively, the pump may be connected between the water supply line and the water outlet without passing through the electric water heater. (13) Unlike the first embodiment, a pressure sensor or the like may be used to detect changes in flow pressure, and current may be supplied to the motor body based on the changes in flow pressure. (14) Unlike the first embodiment, the cold water side impeller and the hot water side impeller may be connected to the rotating shaft without providing a torque limiter. For example, when the hot water / water mixing valve is closed, the rotational resistance generated in the cold water side impeller and the hot water side impeller prevents the motor from operating. When the hot water / water mixing valve is opened, the rotational resistance generated in the cold water side impeller and the hot water side impeller decreases, allowing the motor to start operating. For example, when the hot water / water mixing valve is closed, the motor is overloaded, and the current value supplied to the motor increases. In contrast, when the hot water / water mixing valve is open, the overload state of the motor is resolved, and the current value supplied to the motor decreases. For example, if this current value exceeds the upper current threshold, it may be determined that the motor is not operating and the rotating shaft is not rotating. If this current value is equal to or less than the upper current threshold, it may be determined that the motor is not operating and the rotating shaft is rotating. (15) Unlike the first embodiment, the cold water flow sensor and the hot water flow sensor may be provided in the cold water supply pipe and the hot water supply pipe. (16) The motor may be located adjacent to the hot water side case. (17) Unlike the first embodiment, the hot water side flow path and the cold water side flow path may be formed side by side in a single case. In other words, the hot water side case and the cold water side case may be molded as a single unit. (18) Unlike embodiment 2, the hot water side impeller may be integrally provided with the holder, and the cold water side impeller may be connected to the rotating shaft. Alternatively, the hot water side impeller and the cold water side impeller may be integrally provided with the holder. In this case, the hot water impeller and the cold water side impeller may be connected by a cylindrical connecting member. Alternatively, three or more impellers may be provided. In this case, two of the three impellers, or one of the three impellers, may be integrally provided with the holder, and the remaining impeller may be connected to the rotating shaft. (19) Unlike embodiment 2, the other end of the rotating shaft may be formed into a D-cut shape or serrated, and the inner peripheral shape of the cylindrical part of the hot water side impeller may be formed to match the outer shape of the other end of the rotating shaft. This makes it possible to reliably prevent the hot water side impeller from rotating freely relative to the rotating shaft.

[0084] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive, and the scope of the present disclosure is not limited to the embodiments disclosed herein. [Explanation of symbols]

[0085] 10,110...pump, 11...water side case (case), 11A...water side flow path (fluid flow path), 11B...water side inlet (inlet of water side case), 11C...water side outlet (outlet of water side case), 12...hot water side case (case), 12A...hot water side flow path (fluid flow path), 12B...hot water side inlet (inlet of hot water side case), 12C...hot water side outlet (outlet of hot water side case), 13,113...water side impeller (impeller), 14,114...hot water side impeller (impeller), 15...motor, 15A...motor Motor body, 15B... cover (storage section), 15C... control section, 15E... magnet, 15F... holder, 16... rotating shaft, 17... torque limiter, 18... first seal member (seal member), 50... electric water heater, 51... tank (heating section), 52... water pipe (upstream water supply passage), 53... hot water pipe (upstream hot water supply passage), 70... discharge section, 70B... hot water supply pipe (downstream hot water supply passage), 70C... water supply pipe (downstream water supply passage), 100, 200... electric water heater system, H... hot water (fluid), W... water (fluid)

Claims

1. A plurality of impellers; a plurality of fluid flow paths each having a fluid inlet and a fluid outlet, the plurality of fluid flow paths being disposed separately from each other; a rotating shaft that rotates each of the impellers; a motor that rotates the rotary shaft; It is equipped with The plurality of fluid flow paths are aligned in a line along the rotation axis, The motor is disposed at an end of the aligned fluid flow paths.

2. The pump of claim 1 , further comprising a plurality of cases, each of which defines one of the fluid flow paths.

3. One of the plurality of cases is This is a water-side case placed in the middle of the water flow path, The pump of claim 2 , wherein the motor is adjacent to the water side case.

4. 4. The pump according to claim 1, wherein the motor includes a motor body, a control unit that controls the motor body, and a waterproof housing that houses the control unit.

5. The pump according to claim 4 , wherein the control unit executes power supply start control to gradually increase the magnitude of the current supplied to the motor body when starting power supply to the motor body.

6. The pump according to claim 1 , wherein each of the impellers is coupled to the rotary shaft via a torque limiter.

7. 3. The pump according to claim 2, further comprising a seal member disposed between the adjacent cases, the seal member contacting the outer peripheral surface of the rotary shaft over the entire circumferential direction and preventing the fluid from flowing between the cases.

8. The plurality of cases are a water-side case provided in the middle of a flow path through which water flows and a hot water-side case provided in the middle of a flow path through which hot water flows, The inlet of the hot water side case is connected to an upstream hot water supply passage connected to a secondary side of a heating section that heats water, The outlet of the hot water side case is connected to a downstream hot water supply passage connected to a discharge portion, The inlet of the water side case is connected to an upstream water supply channel connected to the primary side of the heating unit, The pump according to claim 2 , wherein the outlet of the water-side case is connected to a downstream water supply passage connected to the discharge portion.

9. The motor a magnet that rotates together with the rotation shaft; a holder that holds the magnet and connects it to the rotating shaft; and 2. The pump according to claim 1, wherein some of the plurality of impellers are integrally provided with the holder, and the remaining impellers are connected to the rotary shaft.

10. A pump according to claim 8; an electric water heater having the heating unit; Electric water heating system.

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