JP2007147096A - Electric water heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric water heater capable of stopping a heater before hot water in a hot water storage tank is boiled up by keeping a circulation pump in an ON state, even when the heater continues its operation due to deposition in a relay that switches power distribution to the heater. <P>SOLUTION: When a boil-up completion thermistor 10 detects 104°C, after the boil-up terminal thermistor 10 detects 107°C, and the circulation pump 9 is switched to the ON state, the circulation pump 9 is switched to an OFF state until the boil-up completion thermistor 10 detects 107°C again, and this processing is repeated. When a high power source-side protective device 12 detects a hot water temperature of 100°C or more, an AC power source 13 flowing in a high power source-side circuit is cut off, and power distribution to a heater 6 or a heater 7 is stopped. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electric water heater that stores hot water in a hot water storage tank in a laminated form.

Conventionally, hot water storage type electric water heaters circulate water near the bottom of a hot water storage tank to the upper part of the hot water storage tank above the heater. The boiling procedure will be described in detail. First, when the temperature detection means provided at the top of the hot water storage tank detects that the temperature reaches a predetermined temperature B (usually around 90 ° C.), the circulating pump is operated, When the detecting means detects a predetermined temperature A (usually around 85 ° C.), the operation of the circulation pump is stopped. And the boiling operation is completed by repeating this.
JP 2001-065987 A

  By the way, although not described in Patent Document 1, the above-described hot water storage type electric water heater is usually provided with a protector assuming that the temperature detecting means has failed. The protector is provided in a flange portion for fixing the heater to the hot water storage tank, and can shut off the energization to the heater when the protector detects a certain high temperature (for example, 100 ° C.). In particular, this is utilized when the relay for switching the current to the heater becomes uncontrollable due to welding or the like.

  However, in the hot water storage tank, hot water is stored in a laminated state, and the temperature of the layer increases toward the upper side of the hot water tank and conversely decreases toward the lower side. Therefore, when the protector detects 100 ° C. The hot water layer at the top of the hot water storage tank reaches about 120 ° C. When the hot water reaches such a temperature, there is a risk of boiling, and when the user opens a hot water tap such as a curan, hot water at a set temperature or higher may be discharged.

  In order to solve the above-mentioned conventional problems, the electric water heater of the present invention is provided with a boiling pipe connecting the bottom part of the hot water storage tank and the top part, and the water at the bottom part of the hot water storage tank to the top part provided in the middle of the boiling pipe. Circulation pump that circulates, heater that is installed at the top of the hot water tank to heat the hot water in the hot water storage tank, boiling completion thermistor that is installed at the top of the hot water storage tank, and circulating pump according to the temperature detected by the boiling completion thermistor Control means for turning the heater ON or OFF, and power shut-off means for shutting off energization of the heater when the vicinity of the heater of the hot water storage tank reaches the safety set temperature, and the control means is less than the safety set temperature. The circulating pump is switched from the OFF state to the ON state when an abnormal set temperature that is high is detected.

  According to this, even if the relay that switches the current to the heater is welded and the current continues to flow to the heater, the circulation pump is turned on, so the vicinity of the heater reaches the set temperature for safety and the power supply The power supply to the circuit including the heater is cut off by the shut-off means to cut off the power supply to the heater, and the heating by the heater can be stopped before the hot water in the hot water storage tank boils.

  The electric water heater of the present invention switches the circulation pump from the OFF state to the ON state when the set temperature for abnormality is detected, so that the relay for switching the energization to the heater is welded and the heater continues to operate. By turning on the circulation pump, the heater can be stopped before the hot water in the hot water storage tank boils.

  1st invention is provided in the boiling piping which connects the bottom part of a hot water storage tank, and a top part, the circulation pump which is provided in the middle of a boiling piping and circulates the water of a hot water storage tank bottom part to a top part, and provided in the upper part of a hot water storage tank A heater for heating the hot water in the hot water storage tank, a boiling completion thermistor provided at the top of the hot water storage tank, and a control means for turning the circulation pump on or off according to the detected temperature of the boiling completion thermistor, And a power shut-off means for shutting off the heater when the vicinity of the heater in the hot water storage tank reaches the safety set temperature, and the control means is for normal use in which the temperature detected by the boiling completion thermistor is lower than the safety set temperature. Electric hot water that switches the circulation pump from the OFF state to the ON state when the set temperature is detected and when the abnormal set temperature that is higher than the safety set temperature is detected It is.

  According to this, even if the relay for switching the current to the heater is welded and the heater continues to operate, the heater can be stopped before the hot water in the hot water tank boils by turning on the circulation pump. .

  Further, in the second invention, in particular, in the first invention, after the boiling completion thermistor detects the abnormal set temperature and the circulation pump is turned on, the boiling complete thermistor is higher than the safety set temperature. In addition, the control means switches the circulation pump from the ON state to the OFF state when the abnormality canceling set temperature lower than the abnormality setting temperature is detected.

  According to this, before the circulation pump continues to operate and the stacked state in the hot water storage tank is destroyed, the circulation pump is turned off, and the time until the power shutoff means cuts off the power supply to the heater can be shortened.

  In addition, the third aspect of the invention relates to the second aspect of the invention, in particular, in the second aspect of the invention, when the predetermined time has elapsed since the boiling completion thermistor first detected the abnormal set temperature during the boiling operation, If the energization is not cut off, after a predetermined time, the control means switches the circulation pump from the OFF state to the ON state when the boiling completion thermistor detects the second abnormality setting temperature higher than the abnormality setting temperature. It is intended to switch.

  According to this, even when the stacked state in the hot water storage tank collapses, a high temperature hot water layer can be formed in the upper part of the hot water storage tank, so the time until the power shutoff means shuts off the power to the heater is shortened. it can.

  In addition, the fourth aspect of the invention sets the abnormality set temperature and the abnormality release set temperature in the range of 100 ° C. or more and 120 ° C. or less. According to this, the heater can be stopped before the hot water in the hot water storage tank boils.

In addition, the fifth invention,
A boiling pipe that connects the bottom and top of a hot water storage tank that stores hot water in a stack, a circulation pump that is provided in the middle of the boiling pipe to circulate water at the bottom of the hot water tank to the top, and an upper part of the hot water tank The heater that heats the hot water in the hot water storage tank, the boiling completion thermistor installed at the top of the hot water storage tank, and the circulating pump In an electric water heater having a control means for turning off the heater and stopping the energization of the heater, if the heater is energized after it is determined that the boiling operation of the hot water storage tank has been completed, the control means is turned off. The circulating pump in the state is switched to the ON state.

According to this, even if the relay for switching the current to the heater is welded and the heater continues to operate, the heater can be stopped before the hot water in the hot water tank boils by turning on the circulation pump. .

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a diagram illustrating a configuration of an electric water heater according to the first embodiment. The electric water heater in FIG. 1 includes a hot water storage tank 1, and tap water supplied from a water supply pipe 2 is depressurized by a pressure reducing valve 3 and then supplied from the lower part of the hot water storage tank 1. Further, the water supply pipe 2 is connected to a hot water supply mixing valve 4, and the hot water mixing valve 4 mixes the hot water drawn from the top of the hot water storage tank 1 and the tap water supplied from the water supply pipe 2 at an appropriate temperature. The mixed water is discharged from a hot water tap 5 such as a curan. Each time hot water is discharged from the hot water tap 5, tap water for the amount of hot water drawn from the top of the hot water storage tank 1 is supplied from the water supply pipe 2.

  The low temperature water in the hot water storage tank 1 is heated by energizing the heaters 6 and 7 provided in the upper part of the hot water storage tank 1. Normally, the heaters 6 and 7 are energized to perform the boiling operation during the midnight time when the power rate is set at a low price.

  Hot water at different temperatures is distributed in the hot water storage tank 1 in layers, and hot water layers are distributed from the bottom to the top. Therefore, the circulating pump 9 provided in the middle of the boiling pipe 8 connecting the bottom and the top of the hot water tank 1 is turned on, and the hot water in the low temperature layer distributed below the hot water tank 1 is placed above the hot water tank 1. After being circulated, heating by the heaters 6 and 7 is performed.

  When the boiling completion thermistor 10 provided at the top of the hot water storage tank 1 detects 67 ° C., the heaters 6 and 7 are energized and the circulation pump 9 is turned on. At this time, the low temperature hot water layer in the lower part of the hot water storage tank 1 flows into the top through the boiling pipe 8, and the high temperature hot water layer in the upper part of the hot water storage tank 1 moves downward. When the boiling completion thermistor 10 detects 65 ° C., the circulating pump 9 is turned off, and the low temperature hot water layer flowing into the top is heated by the heaters 6 and 7. This operation is repeated until the entire hot water in the hot water storage tank 1 reaches 65 ° C.

  Next, when the detected temperature of the boiling completion thermistor 10 reaches 88 ° C. (corresponding to the set temperature for normal use described in the claims), the heaters 6 and 7 are energized and the laminated pump 9 is turned on, When the detected temperature of the raising completion thermistor 10 reaches 85 ° C., the laminated pump 9 is turned off. This operation is continued until the boiling completion thermistor 10 detects 89 ° C. for 60 seconds continuously. If the boiling completion thermistor 10 detects 89 ° C. continuously for 60 seconds, the energization to the heaters 6 and 7 is stopped, and the stacking pump 9 is turned off to complete the boiling operation. As a result, the entire hot water in the hot water storage tank 1 becomes 89 to 90 ° C.

  The top of the hot water storage tank 1 is provided with a low power supply side protector 11 and a high power supply side protector 12 (corresponding to the power shutoff means described in the claims) in the vicinity of the heaters 6 and 7 of the hot water storage tank 1. ing. The low power supply side protector 11 is installed in preparation for an operation failure or failure of the boiling completion thermistor 10, and when the low power supply side protector 11 detects 97 ° C., the energization to the heaters 6 and 7 is stopped. Like to do. Further, the high power side protector 12 is provided in a flange portion for fixing and installing the heaters 6 and 7 to the hot water storage tank 1, and is provided in case of malfunction or failure of the boiling completion thermistor 10 and the low power side protector 11. When the high-power side protector 12 is attached and detects 100 ° C. (corresponding to the set temperature for protection described in the claims), it supplies power to the control circuit to which the heaters 6 and 7 are connected. Try to block. As a result, it is possible to avoid the occurrence of airing or the like.

  FIG. 2 shows a control circuit diagram in which the heaters 6 and 7 are connected. The heaters 6 and 7, the high power supply side protector 12, the AC power supply 13, and the relays 14 and 15 form a high power supply side circuit. The DC power supply 16, the control unit 17, and the low power supply side protector 11 form a low power supply circuit, and the high power supply circuit and the low power supply circuit are connected by relays 14 and 15.

  When the low-power side protector 11 detects 97 ° C., the relays 14 and 15 are controlled by the controller 17 and the energization of the heaters 6 and 7 is stopped. When the high power side protector 12 detects 100 ° C., the high power side protector 12 shuts off the AC power source 13 flowing through the high power side circuit.

  By the way, when the relays 14 and 15 are welded and the energization of the heater 6 or the heater 7 becomes uncontrollable, the boiling operation is completed even if the boiling thermistor 10 detects 89 ° C. continuously for 60 seconds. After that, the heater 6 or the heater 7 is energized. And even if the hot water temperature layer distributed in the top part of the hot water storage tank 1 reaches 97 ° C. and the low power supply side protector 11 detects 97 ° C., the energization to the heater 6 or the heater 7 can be controlled. The hot water temperature layer continues to rise further.

  At this time, the high-power side protector 12 is unlikely to detect 100 ° C. This is because the hot water in the hot water storage tank 1 is formed at different temperatures, and the hot water layer that exceeds 100 ° C. is lighter in specific gravity than the low temperature hot water layer and is formed on the top of the hot water storage tank 1.

  Therefore, if the boiling completion thermistor 10 detects 107 ° C. (corresponding to the set temperature for abnormality described in the claims), the low temperature hot water layer distributed at the bottom of the hot water storage tank 1 when the circulation pump 9 is turned on. Flows into the top of the hot water storage tank 1 and the 107 ° C temperature layer temporarily distributed on the top of the hot water storage tank 1 is pushed downward, and the high power side protector 12 detects the hot water temperature above 100 ° C. Will be able to. As a result, the power supply side protector 12 cuts off the AC power supply 13 flowing through the high power supply side circuit, and the energization to the heater 6 or the heater 7 is cut off.

  When the boiling completion thermistor 10 detects 107 ° C., the circulation pump 9 is turned on, so that the high power side protector 12 can detect a hot water temperature of 100 ° C. or higher. When the amount of hot water forming the layer is small and the layer width is relatively thin, the low temperature hot water layer distributed at the bottom of the hot water storage tank 1 may flow into the top and the 107 ° C. temperature layer may disappear. In this case, the ON state of the circulation pump 9 is continued and the hot water temperature layer formed in the hot water storage tank 1 is destroyed, so that the boiling completion thermistor 10 detects 107 ° C. again and supplies the heater 6 or the heater 7 to the heater. It will take more time to stop energization.

  Therefore, after the boiling completion thermistor 10 detects 107 ° C. and turns the circulation pump 9 ON, if the boiling completion thermistor 10 detects 104 ° C., the boiling completion thermistor 10 again detects 107 ° C. The circulation pump 9 is turned off. By repeating this process, the hot water temperature layer formed in the hot water storage tank 1 can be prevented from collapsing, and in particular, the layer width can be increased while preventing the hot water layer formed in the top of the hot water storage tank 1 from collapsing. Therefore, the time until the high-power side protector 12 detects a hot water temperature of 100 ° C. or higher can be shortened.

  The same effect can be obtained even when the boiling thermistor 10 detects 107 ° C. and turns the circulation pump 9 on, and then turns the circulation pump 9 off after a predetermined time.

(Embodiment 2)
In the first embodiment, the boiling completion thermistor 10 repeats the ON state and the OFF state of the circulation pump 9 according to the detected temperature, thereby preventing collapse of the hot water layer formed at the top of the hot water storage tank 1. The layer width can be increased. However, the processing shown in FIG. 3 may be performed in order to accelerate the time until the high power side protector 12 detects a hot water temperature of 100 ° C. or higher.

  In FIG. 3, the vertical axis represents temperature, the horizontal axis represents time, the temperature detected by the boiling completion thermistor 10 during the boiling operation is indicated by a solid line, and the temperature detected by the high power side protector 12 is indicated by a dotted line. Further, t1 indicates the time when the boiling completion thermistor 10 first detects 107 ° C. during the boiling operation, and t2 indicates the time after a predetermined time has elapsed from t1.

  In FIG. 3, when the high-power side protector 12 does not detect 100 ° C. until t2 elapses from t1, the temperature detected by the boiling completion thermistor 10 is 110 ° C. (second abnormality setting according to claim) The circulation pump 9 is not turned on until the temperature corresponds to the temperature. Then, when the boiling completion thermistor 10 detects 107 ° C., the circulation pump 9 is turned off.

  As a result, the temperature detected by the high-power side protector 12 rises in conjunction with the temperature of the temperature layer at the top of the hot water storage tank 1 rising, and if the high-power side protector 12 detects 100 ° C. The AC power supply 13 flowing through the high power supply side circuit is cut off, and the energization of the heater 6 or the heater 7 is cut off.

  In this embodiment, the temperature layer distributed in the top of the hot water storage tank 1 is controlled so as not to exceed 110 ° C. However, when the temperature layer exceeds 120 ° C., the hot water boils and boiles from the relief valve 18. Since not only water is discharged but also boiling water may be unexpectedly discharged from the hot water tap 5, the temperature layer distributed over the top of the hot water storage tank 1 is 120 ° C. or less. Must be controlled.

  As described above, even if the relay for switching energization to the heater is welded and the heater continues to operate, the heater can be stopped before the hot water in the hot water tank boils by turning on the circulation pump. Therefore, it can be applied to an electric water heater having a hot water storage tank.

Configuration diagram of electric water heater of this embodiment Control circuit diagram of the present embodiment Hot water temperature transition diagram in the hot water storage tank of this embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hot water storage tank 2 Water supply pipe 3 Pressure reducing valve 4 Hot-water supply mixing valve 5 Hot-water tap 6, 7 Heater 8 Boiling piping 9 Circulation pump 10 Boiling completion thermistor 11 Low power supply side protector 12 High power supply side protector 13 AC power supply 14, 15 Relay 16 DC power supply 17 Control unit 18 Relief valve

Claims (5)

A boiling pipe connecting the bottom and top of a hot water storage tank for storing hot water in a stack; a circulation pump provided in the middle of the boiling pipe for circulating water at the bottom of the hot water storage tank to the top; and A heater provided at the top for heating hot water in the hot water storage tank, a boiling completion thermistor provided at the top of the hot water storage tank, and the circulation pump being turned on or off according to the detected temperature of the boiling completion thermistor In the electric water heater, comprising: a control means for setting a state; and a power shut-off means for shutting off the energization to the heater when the vicinity of the heater of the hot water storage tank reaches a set temperature for safety. When the normal setting temperature detected by the completion temperature increase thermistor is lower than the set temperature for safety, and the set temperature for abnormality that is higher than the set temperature for safety are detected. If issued, electric water heater, characterized in that switching the circulation pump from the OFF state to the ON state. After the boiling completion thermistor detects the abnormal setting temperature and the circulation pump is turned on, the boiling completion thermistor sets the abnormality canceling setting temperature higher than the safety setting temperature and lower than the abnormality setting temperature. 2. The electric water heater according to claim 1, wherein when detected, the control means switches the circulation pump from the ON state to the OFF state. If the power shut-off means does not cut off the power supply to the heater after a predetermined time has elapsed since the first set temperature for abnormality was detected during the boiling operation by the boiling completion thermistor for the first time, the control means 3. The electric water heater according to claim 2, wherein when the boiling completion thermistor detects a second abnormality set temperature higher than the abnormality set temperature, the circulation pump is switched from the OFF state to the ON state. The electric water heater according to claim 3, wherein the abnormality setting temperature and the abnormality canceling setting temperature are set in a range of 100 ° C to 120 ° C. A boiling pipe connecting the bottom and top of a hot water storage tank for storing hot water in a stack; a circulation pump provided in the middle of the boiling pipe for circulating water at the bottom of the hot water storage tank to the top; and A heater for heating hot water in the hot water storage tank provided at the top, a boiling completion thermistor provided at the top of the hot water storage tank, and the boiling operation of the hot water storage tank are completed by the temperature detected by the boiling completion thermistor And an electric water heater comprising a control means for turning off the circulation pump and stopping energization of the heater when it is determined that the heater has been heated to the heater after determining that the boiling operation of the hot water storage tank has been completed. An electric water heater according to claim 1, wherein when energization has been performed, the control means switches the circulation pump that has been turned off to an on state.

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