JP5256854B2 - Water heater - Google Patents

Description

  The present invention relates to a hot water supply apparatus having a bath circulation function.

  In the conventional hot water supply apparatus, the rotation speed is made constant by performing feedback control on the rotation speed of the bath circulation pump in the bath circulation circuit. (For example, see Patent Document 1)

JP 2006-300388 A

  A conventional hot water circulation pump of a hot water supply apparatus uses a DC pump and applies feedback control to the rotational speed. The rotational speed of the DC pump varies greatly depending on the rotational load. When the return pipe is in the absence of water, the rotational load is reduced, so the control sensitivity is increased and the feedback control system becomes unstable. If the control parameters are tuned to match this, the rise time of the rotational speed becomes longer in the operation when the control sensitivity is low, that is, when the return pipe having a large rotational load is in a water-containing state. Then, there was a problem that it took time to circulate hot water in the return pipe and draw hot water in the bathtub.

  The present invention has been made in view of the above, and switches the control parameter of the bath circulation pump according to the remaining water state of the bath return pipe, shortens the rise time of the rotation speed of the bath circulation pump, and The purpose is to obtain an easy-to-use hot water supply device that shortens the time to draw in the water.

The hot water supply apparatus of the present invention detects a bath circulation circuit that takes out hot water from a bathtub and returns it to the bathtub, a bath pump that is provided in the bath circulation circuit and that is driven by DC power that circulates hot water in the bathtub, and detects the number of rotations of the bath pump. Rotational speed detection means, residual water state detection means for detecting changes in the residual water state in the bath circulation circuit, and feedback control that provides a speed command signal to the bath pump based on the rotational speed of the bath pump and a predetermined target rotational speed And a change in the number of rotations of the bath pump per unit time by the feedback control unit when a water-existing state is detected, compared to a case where no water state is detected by the remaining water state detecting unit. Control parameter switching means for switching control parameters.

  According to the bath circulation device of the present invention, the control parameter of the bath circulation pump is switched according to the remaining water state of the bath return pipe, the rise time of the rotation speed of the bath circulation pump is shortened, and the time for drawing in the bath water is shortened. It is possible to obtain a hot water supply device that is easy to use.

Embodiment 1 FIG.
FIG. 1 is a configuration diagram of a hot water storage type water heater that is a hot water supply apparatus according to Embodiment 1 of the present invention, FIG. 2 is a control flowchart of a bath circulation pump according to Embodiment 1 of the present invention, and FIG. 3 is an embodiment of the present invention. It is a figure which shows the rotation speed rising state of the bath circulating pump by the form 1. Hereinafter, the details of this configuration will be described with reference to the drawings.

  In the hot water storage type water heater 1 of FIG. 1, the hot water storage tank 7 stores hot water or hot water, and a heating circulation circuit 22 is connected to a heat pump unit 21 that is a heating means. In the heat circulation circuit 22, a circulation pump (not shown) is provided in the heat pump unit 21, and water is led from the lower part of the hot water storage tank 7, heat exchange with the outside air is performed by the heat pump, The hot water is boiled and returned to the upper part of the hot water storage tank 7.

  On the other hand, the hot water supply pipe 23 has one end connected to the upper part of the hot water storage tank 7 and the other end connected to the hot water supply port of the hot water hot water mixing valve 17 and the general hot water hot water mixing valve 18 to bathe hot water stored in the hot water storage tank 7. This is a pipe for supplying the hot water mixing valve 17 and the general hot water mixing valve 18. The water supply pipe 19 is connected to a water source such as a water pipe, and the pressure reducing valve 13 is attached to the water supply pipe 19 to reduce the water source water pressure, and one end of the water supply pipe 19 is connected to the water supply port of the hot water supply mixing valve 17 and the general hot water supply mixing valve 18. The water source is connected to supply water, and the other end is connected to the lower part of the hot water storage tank 7 to supply water into the hot water storage tank 7. To the hot water supply mixing valve 17, there is connected a hot water supply pipe 5 for sending the mixed hot water from the hot water supply mixing valve 17 to the bath circulation circuit 4. A bath water supply solenoid valve 16 that supplies and stops the mixed hot water, a bath hot water flow rate sensor 32 that detects the flow rate of the mixed hot water, and a bath for correcting temperature of the bath hot water mixing valve 17 are provided in the bath hot water supply pipe 5. An outgoing temperature sensor 25 is provided and connected to the bath circuit 4. A hot water supply pipe 23 in the vicinity of the upper part of the hot water storage tank 7 is provided with a relief valve 34 for releasing hot water in the hot water storage tank 7 that has undergone volume expansion during boiling. The general hot water supply mixing valve 18 is connected to a general hot water supply pipe 20 for sending the mixed hot water from the general hot water supply mixing valve 18 to a kitchen faucet or the like.

  Connected to the upper and lower portions of the hot water storage tank 7 is a tank circulation circuit 6 for returning the hot water stored in the hot water storage tank 7 to the hot water storage tank 7. The tank circulation circuit 6 includes a heat exchanger 14 for exchanging heat between hot water stored in the hot water storage tank 7 and bath water in the bathtub 2, and a bath circulation heat source pump 15 for circulating hot water in the hot water storage tank 7 to the tank circulation circuit 6. It is configured.

  A bathtub adapter 3 is attached to the bathtub 2, and a bath circulation circuit 4 is connected through the bathtub adapter 3. This bath circulation circuit 4 is connected to a heat exchanger 14, a bath circulation pump 12 for circulating hot water in the bathtub 2, and a bathtub adapter 3 and a heat exchanger 14, and draws hot water in the bathtub 2 into the hot water storage hot water heater 1 during circulation. It comprises a return pipe 8 and a return pipe 9 which is connected to the heat exchanger 14 and the bathtub adapter 3 and supplies hot water from the return pipe to the bathtub 2 during circulation. Further, a flow switch 11 is interposed in the bath circuit 4 as water flow detection means to detect the presence or absence of the water flow of the bathtub water, and a water level sensor 10 is interposed to detect the water level of the bathtub 2.

  The bath circulation pump 12 is a DC pump, and has a function of outputting the rotation speed of the bath circulation pump 12 as a rotation speed signal and a function of changing the rotation speed in accordance with the applied speed command signal.

  The control unit 35 of the hot water storage type hot water heater 1 is controlled based on the rotation speed detection means 354 that reads the rotation speed from the rotation speed signal of the bath circulation pump 12, the predetermined target rotation speed, and the rotation speed detected by the rotation speed detection means 354. The control parameters of the feedback control means 351 for calculating the pump speed command signal using the parameters, the pipe residual water state detection means 353 for detecting the change in the residual water presence / absence state in the bath circulation circuit 4, and the feedback control means 351 are switched. Control parameter switching means 352 is provided. In the control unit 35, the pipe residual water state detection unit 353 detects the pipe residual water state of the bath circuit 4, and the control parameter switching unit 352 switches the control parameter of the feedback control unit 351 in accordance with the pipe residual water state. The rotary circulation pump 12 has a large number of revolutions depending on the rotational load, and the control sensitivity is increased when the bath return pipe 8 is in the absence of water. Therefore, the control parameter without pipe water is set to a small feedback gain according to the large control sensitivity to stabilize the control system, and the control parameter with pipe water is rotated by increasing the feedback gain according to the small control sensitivity. Set so that the rise time is faster.

  Next, the control parameter switching operation of the bath circulation pump 12 when the hot water storage hot water heater 1 having the above-described configuration is filled will be described. When hot water filling is set by a remote controller (not shown) connected to the hot water storage type hot water heater 1, a predetermined amount of hot water is supplied to the bathtub 2 as priming water, and the bath circulation circuit 4 is filled with hot water. Next, as the bathtub water drawing operation, the bath circulation pump 12 is operated to circulate the hot water in the bath circulation circuit 4 and to draw the hot water in the bathtub 2 to the bath circulation circuit 4. After the bath circulation pump 12 is operated for a time sufficient to draw hot water in the bathtub 2, the presence or absence of water flow by the flow switch 11 is detected by the pipe residual water state detection means 353 to determine the presence or absence of the bathtub water. When it is determined that there is no hot water in the bathtub 2, the hot water set amount and the hot water set amount set by the remote controller are supplied to the bathtub 2, and when the set hot water amount is reached, the water level is detected by the water level sensor 10 and the control unit 35. The hot water filling operation is completed. If there is hot water in the bathtub 2, the hot water temperature and the water level of the bathtub 2 are observed, and after chasing to the set temperature, hot water is supplied to the bathtub 2 up to the set hot water level.

  Hereinafter, for explanation, the threshold rotation speed of the bottom circulation pump that determines that the bottom return pipe 8 of the bottom circulation circuit 4 is in a water-free state is defined as P. The threshold rotational speed P is a predetermined rotational speed above the target rotational speed.

  Next, the operation of the bath circulation pump 12 according to the present invention will be described with reference to the flowchart shown in FIG. When bath water is drawn during the hot water filling, the controller 35 starts the operation of the bath circulation pump 12 (step S1), sets the target rotational speed of the bath water drawing operation (step S2), The control parameter by the feedback control means 351 is set to the one without pipe water by the control parameter switching means 352 (step S3).

  Next, the rotational speed of the bottom circulation pump 12 is detected by the rotational speed detection means 354, and it is determined whether the rotational speed is equal to or less than a preset threshold rotational speed P (step S5). If the rotation speed of the bath circulation pump 12 is less than or equal to the threshold rotation speed P, the process proceeds to step S6. If the rotation speed of the bath circulation pump 12 exceeds the threshold rotation speed P, the bath circulation circuit 4 changes to a state without pipe water. Alternatively, it is determined that there is no water (step S8), and the control parameter switching unit 352 sets the control parameter used in the feedback control unit 351 to a state without piping water (step S9). Here, as a reason for determining the presence or absence of the pipe residual water in the bath circulation circuit 4, if the pipe residual water state does not change, the feedback control means 351 causes the rotation speed of the bath circulation pump 12 to be near or below the target rotation speed. Although it is controlled, when the remaining water state of the piping of the bath circulation circuit 4 is changed from being present to being absent, the rotational speed is rapidly increased due to a rapid decrease in the rotational load. Therefore, it can be determined that the pipe water is not in a state where there is no pipe water when the rotational speed of the circulating pump 12 exceeds the threshold rotational speed P set above the target rotational speed.

  In step S6, the flow switch 11 is continuously turned on for a predetermined time (in this case, set to 3 seconds), that is, whether the presence of water flow is detected is determined by the pipe residual water state detecting means 353 and turned on continuously for a predetermined time. If so, the circulation circuit 4 determines that the pipe water is present (step S6), and the control parameter switching means 352 sets the control parameter used by the feedback control means 351 to the pipe water present state (step S7). In step S5, if the flow switch 11 does not satisfy the condition of continuous ON for a predetermined time, it is determined that the remaining water state of the piping circuit 4 has not changed without water, and the control parameter switching means 352 controls the control parameter. The process goes to step S10 without changing.

  In step S10, the feedback control means 351 sets the rotation speed of the bath circulation pump 12 to the target rotation based on the set control parameter of the bath circulation pump 12 and the rotation speed of the bath circulation pump 12 detected by the rotation speed detection means 354. The speed command signal is changed so as to match the number (feedback control). Since the control sensitivity of the water circulation pump 12 in the state with pipe water is low, the rotation speed is unlikely to increase even when the speed command signal changes. The signal can be changed greatly. By appropriately switching the control parameters in this way, as shown in FIG. 3, it is shorter when the control parameters are switched with respect to the passage of time after detecting the presence of water (the horizontal axis in FIG. 3). The target rotational speed can be reached in time, and the rise time of the rotational speed can be shortened. If the rotation speed rise time of the bath circulation pump 12 is shortened, the rise time of the circulation flow rate in the bath circulation circuit 4 is also shortened, so that the time for drawing in the bath water can be shortened. The bathtub water drawing operation is used not only for hot water filling, but also for other bathing functions, and is performed to confirm the presence or absence of the bathtub water before operation when reheating or hot water. If the time for drawing in the bath water is shortened, these various operation times can be shortened, and the usability of the hot water storage type hot water heater 1 is improved.

  In step S11, it is determined whether or not there is an instruction to stop the bath circulating pump 12, and if the detection of the presence or absence of bath water ends after a predetermined bath water drawing-in time, the stop command is issued, so the process proceeds to step S12, and the control unit 35 Stops the circulation pump 12. If there is no stop command, the process returns to step S4.

  In the first embodiment described above, the change in the pipe residual water state of the bath circulation circuit 4 is detected by the rotation speed of the bath circulation pump 12 and the threshold rotation speed P. However, it is also possible to detect the change in the presence or absence of water flow by the water flow detection means. It can be realized. For example, the flow switch 11 is used as the water flow detection means, and the control unit 35 monitors the output signal from the flow switch 11 and detects a change from ON (with hot water flow) to OFF (no hot water flow). The circulation circuit 4 determines that the pipe water is not present. Furthermore, it is possible to detect the residual water state of the pipe from the combination of the rotational speed of the bath circulation pump 12 and the speed command signal. The circulation pump 12 has a higher rotational speed in the absence of piping water with a small rotational load than in a piping water presence state with a large rotational load even with the same speed command signal. Therefore, the characteristics of the voltage-rotation speed rotation speed are examined in advance by using, as the speed command signal, the circulation pump 12 whose speed is proportional to the control voltage. For example, if the rotation speed of the circulation pump 12 when the control voltage is 4V is 2000 rpm in the state with pipe water, and 6000 rpm without the pipe water, if the rotation speed is 4000 rpm or less when the control voltage is 4V, Otherwise, it is detected that there is no piping water. As described above, the situation of the residual pipe water is judged, and the control parameter of the bath circulation pump 12 is switched in accordance with the residual pipe water state. The pull-in time can be shortened.

  As described above, according to the present invention, the target rotation can be achieved in a shorter time by switching the control parameter of the feedback control means 351 that controls the bath circulation pump 12 according to the remaining water state in the bath circulation circuit 4. The number can be reached. Further, if the rotation speed rise time of the bath circulation pump 12 is shortened, the rise time of the circulation flow rate in the bath circulation circuit 4 is also shortened, so that the time for drawing in the bath water can be shortened. The bathtub water drawing operation is used not only for hot water filling, but also for other bathing functions, and is performed to confirm the presence or absence of the bathtub water before operation when reheating or hot water. If the time for drawing in the bath water is shortened, these various operation times can be shortened, and the usability of the hot water storage type hot water heater 1 is improved.

It is a block diagram of the hot water supply apparatus which shows Embodiment 1 of this invention. It is a control flowchart of the bath circulating pump in Embodiment 1 of this invention. It is a figure which shows the rotation speed rising state of the bath circulation pump by Embodiment 1 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hot water storage type water heater 2 Bathtub 3 Bathtub adapter 4 Bath circulation circuit 5 Bath hot water supply path 6 Tank circulation circuit 7 Hot water storage tank 8 Bath return piping 9 Bath going piping 10 Water level sensor 11 Flow switch 12 Bath circulating pump 13 Pressure reducing valve 14 Heat exchanger DESCRIPTION OF SYMBOLS 15 Flowing heat source pump 16 Flowing hot water solenoid valve 17 Flowing hot water mixing valve 18 General hot water mixing valve 19 Water supply piping 20 General hot water supply path 21 Heat pump unit 22 Heating circulation circuit 23 Hot water supply piping 25 Bathing temperature sensor 32 Flow for hot water supply Sensor 34 Relief valve 35 Control unit 351 Feedback control means 352 Control parameter switching means 353 Pipe residual water state detection means 354 Rotation speed detection means

Claims (4)

A bath circulation circuit for taking out hot water from the bathtub and returning it to the bathtub;
A bath pump that is provided in the bath circulation circuit and that is driven by direct current power that circulates hot water in the bathtub;
A rotational speed detection means for detecting the rotational speed of the bath pump;
A residual water state detection means for detecting a change in the residual water state in the bath circuit,
Feedback control means for providing a speed command signal to the bath pump based on the rotational speed of the bath pump and a predetermined target rotational speed;
Control parameter so that the change in the number of rotations of the bath pump per unit time by the feedback control unit when the water remaining state is detected is larger than when the remaining water state is detected by the remaining water state detecting unit. Control parameter switching means for switching between,
A hot water supply apparatus comprising: The remaining water state detecting means detects that no water is in the bath circulation circuit when the rotation speed of the bath pump exceeds a predetermined rotation speed higher than a target rotation speed. The hot water supply device according to claim 1, wherein detection is performed by a provided water flow detection means. The hot water supply apparatus according to claim 2, wherein the remaining water state detecting means detects a change in the remaining water state in the bath circulation circuit by the water flow detecting means. The said residual water state detection means detects the residual water state in the said bottom circulation circuit by the rotation speed detected by the said rotation speed detection means with respect to the said speed command signal of the said bath pump. Water heater.

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