JP2008145083A - Bypass mixing type hot water supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hot water supply device including a bypass passage 3 connecting both upper and lower passage parts of a heat exchanger 2 of a water flow passage 1, a hot water temperature sensor 10 in the vicinity of an outlet of the heat exchanger 2, a flow rate sensor 15 for detecting the flow rate of hot water supplied, and a hot water and water mixer 4 for mixing cold water from the bypass passage 3 and hot water from the heat exchanger, inhibiting the heat exchanger 2 from being heated by the gas burner 5 for a long time when the water flow passge 1 is clogged in determining clogging of the water flow passage in the case where a difference between a post-ignition temperature detected by the hot water sensor 10 and a pre-ignition temeprature detected by the hot water sensor 10 before ignition is below a reference temperature difference. <P>SOLUTION: The standby time is shortened with an increase in detected flow rate of the flow rate sensor 15, and also it is set above the time required for hot water heated to an elevated temperature by the heat exchanger 2 to reach the disposition part of the hot water sensor 10. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a so-called bypass mixing type hot water heater in which hot water heated and heated by a heat exchanger is mixed with cold water to take out hot water at a hot water supply set temperature, and a water passage passing through the heat exchanger is clogged. It is related with the water heater provided with the function to detect.

FIG. 1 is a schematic view of a water circuit and a gas circuit in the bypass mixing type water heater.
The water passage (1) is connected to the faucet (14) via the heat exchanger (2) from the place where the incoming water temperature sensor (18) and the flow rate sensor (15) are arranged, and the heat exchanger (2) The upstream part and the downstream part are connected by a bypass (3). In addition, the mixing ratio (13) of the bypass channel (3) and the water flow channel (1) is set with the mixing ratio of hot water heated by the heat exchanger (2) and cold water from the bypass channel (3). A hot and cold water mixer (4) is provided. A hot water temperature sensor (10) is disposed near the outlet of the heat exchanger (2) in the water passage (1), and a mixed water temperature sensor (11) is disposed downstream of the hot water mixer (4). It is installed.

In addition, the gas circuit (50) to the gas burner (5) for heating the heat exchanger (2) is provided with a gas proportional valve (51) and ignites this in the vicinity of the gas burner (5). An ignition electrode (52) is provided for this purpose.
In this case, when the hot water supply temperature is set with a temperature setter (not shown) and the faucet (14) is opened, the flow rate sensor (15) detects a flow rate higher than the burner ignition flow rate (usually 2.7 L / min). Then, sparks for ignition start from the ignition electrode (52) to the gas burner (5). On the other hand, based on the detected flow rate of the flow rate sensor (15), the feed water temperature detected by the incoming water temperature sensor (18), and the set hot water temperature (hereinafter referred to as “hot water set temperature”), The required amount of combustion of the gas burner (5) required to generate the gas in the water heater is calculated. Then, the opening degree of the gas proportional valve (51) is set according to the required combustion amount. As a result, the water flow through the heat exchanger (2) is heated and heated by the combustion exhaust of the gas burner (5), and the detected temperature of the mixed water temperature sensor (11) approaches the hot water supply set temperature. The mixing ratio of hot water from (2) and cold water from the bypass (3) is set by the hot water mixer (4).
In this device, a part of the water supplied to the water passage (1) is branched to the bypass passage (3), and the remaining water is distributed to the heat exchanger (2) side.

Therefore, since the bypass passage (3) is not provided, the entire water flow is different from that flowing through the heat exchanger (2), and the combustion exhaust of the gas burner (5) is not easily cooled below the dew point by the heat exchanger (2). Thus, there is an advantage that the generation of drain in the heat exchanger (2) portion can be suppressed.
In this, the heated zone (1a) sandwiched between the branch point (12) and the junction (13) of the bypass channel (3) in the water channel (1) freezes in the cold winter season, Further, when clogged due to accumulation of dust or the like, the clogging is detected and combustion of the gas burner (5) can be prohibited.

Specifically, the temperature detected by the hot water temperature sensor (10) before ignition of the gas burner (5) is stored as the pre-ignition temperature. The temperature detected by the hot water temperature sensor (10) is stored as the post-ignition temperature when the standby time (about 10 seconds) has elapsed after the ignition of the gas burner (5), and there is a difference between the pre-ignition temperature and the post-ignition temperature. If not, it is determined that the heated area (1a) is clogged. If it is determined that the heated area (1a) is clogged, the gas burner (5) is extinguished to ensure a safe state.
Japanese Patent Laid-Open No. 11-173670

  In the above conventional apparatus, the standby time until the temperature is detected by the hot water temperature sensor (10) after the gas burner (5) is ignited is uniformly set to about 10 seconds. The waiting time is necessary for the hot water heated by the heat exchanger (2) to reach the location of the hot water temperature sensor (10) at the time of the minimum hot water supply for burning the gas burner (5) with the minimum combustion amount. Thus, clogging of the heated area (1a) passing through the heat exchanger (2) can be detected regardless of the opening of the faucet (14), that is, the amount of hot water supply.

  However, in the above-mentioned conventional one, when supplying a large amount of hot water with the opening of the faucet (14) increased, the hot water heated by the heat exchanger (2) is quickly transferred to the arrangement portion of the hot water temperature sensor (10). In spite of the arrival, the temperature detection by the hot water temperature sensor (10) is not performed unless a long standby time uniformly set in accordance with the minimum hot water supply has elapsed. For this reason, when a large amount of hot water is supplied, there is a time difference between the time required for the hot water heated by the heat exchanger (2) to reach the portion where the hot water temperature sensor (10) is disposed and the waiting time.

Therefore, when the heated area (1a) passing through the heat exchanger (2) is clogged during hot water supply with a large opening of the faucet (14), compared to the case where the waiting time is set in accordance with the hot water supply. The heat exchanger (2) is heated by the gas burner (5) for a long time by the time difference, and an excessive heat load is applied to the heat exchanger (2).
Contrary to the conventional one, when the standby time is set to a short time in accordance with the hot water supply, the hot water heated by the heat exchanger (2) is heated by the hot water temperature sensor (10) at the minimum hot water supply. Since the temperature detection by the hot water temperature sensor (10) is executed before reaching the arrangement portion, it is impossible to determine whether the heated circuit (1a) is clogged.

The present invention has been made in view of such points.
`` A water passage (1) in which a heat exchanger (2) heated by a gas burner (5) and a hot water temperature sensor (10) are arranged in this order from the upstream side,
A bypass passage (3) connecting the upstream portion of the heat exchanger (2) and the downstream portion of the hot water temperature sensor (10) in the water passage (1),
A flow rate sensor (15) for detecting a flow rate upstream of the branch point (12) of the bypass channel (3) or downstream of the junction (13) in the water flow channel (1);
A hot water mixer (4) that adjusts cold water supplied from the bypass passage (3) and hot water from the heat exchanger (2) to a hot water at a hot water set temperature by mixing the water at a predetermined ratio. A vessel,
When the flow sensor (15) detects a preset burner ignition flow rate, the gas burner (5) is ignited,
The difference between the post-ignition temperature detected by the hot water temperature sensor (10) after a predetermined waiting time after the ignition and the pre-ignition temperature detected by the hot water temperature sensor (10) before the ignition is a reference temperature. In the case where the difference is less than or equal to the difference, in the water heater that determines that the heated area (1a) sandwiched between the junction (12) and the junction (13) of the water passage (1) is,
When the heated area (1a) passing through the heat exchanger (2) is clogged during mass water supply, the gas exchanger (5) prevents the heat exchanger (2) from being heated for a long time. An object of the present invention is to prevent inconvenience that an excessive thermal load is applied to the heat exchanger (2).

[Invention of Claim 1]
The solution means of the invention according to claim 1 for solving the above-mentioned problem is as follows:
“The waiting time is shortened as the flow rate detected by the flow rate sensor (15) increases, and hot water heated by the heat exchanger (2) is transferred to the hot water temperature sensor (10). It is set more than the time required to reach the station.
The above solution works as follows.
The detected flow rate of the flow rate sensor (15) increases with an increase in the amount of hot water supply, and the heated area (1a) passing through the heat exchanger (2) as the detected flow rate of the flow rate sensor (15) increases. The flow rate increases.
The reason why the flow rate in the heated area (1a) increases as the flow rate detected by the flow rate sensor (15) increases is as follows.
The hot water mixer (4) only sets the mixing ratio of cold water from the bypass (3) and hot water from the heat exchanger (2), so the flow rate detected by the flow sensor (15) (total flow rate of hot water supply) This is because the flow rates of the heated zone (1a) and the bypass passage (3) both increase at the same rate as the increase rate.

  Now, as the flow rate of the heated area (1a) passing through the heat exchanger (2) increases with an increase in the detected flow rate of the flow sensor (15), the heat exchanger (2) The heated hot water reaches the location of the hot water temperature sensor (10) (located between the heat exchanger (2) and the junction (13) of the bypass passage (3)). The required time is shortened. In this case, according to the above solution, since the detected flow rate of the flow rate sensor (15) is increased, the hot water heated by the heat exchanger (2) is heated by the arrangement portion of the hot water temperature sensor (10). The waiting time set longer than the time required to reach the time is shortened.

Therefore, when the heated area (1a) that passes through the heat exchanger (2) is clogged when supplying a large amount of hot water, the heat exchanger is compared to the conventional one described above, in which the standby time is set longer in accordance with the minimum hot water supply. The time during which (2) is heated by the gas burner (5) is shortened. Thereby, there is no inconvenience that an excessive heat load is applied to the heat exchanger (2).
When the heated area (1a) passing through the heat exchanger (2) is not clogged during hot water supply, the hot water heated by the heat exchanger (2) is placed in the hot water temperature sensor (10). The hot water temperature sensor (10) detects the temperature of the hot water after the elapse of the standby time set longer than the time required to reach the section. This confirms that the heated area (1a) passing through the heat exchanger (2) is not clogged. On the other hand, when supplying a small amount of hot water, the flow rate detected by the flow sensor (15) is small, so the waiting time is set to a long time, and the temperature of hot water heated by the heat exchanger (2) is set to the temperature of the hot water temperature sensor (10 ) Is detected. Thereby, it can be judged whether the said to-be-heated area (1a) is clogged at the time of small amount hot water supply.

The present invention has the following specific effects.
As described above, when the heated area (1a) passing through the heat exchanger (2) in the water passage (1) is clogged during hot water supply, the waiting time is set longer in accordance with the minimum hot water supply. Compared to the conventional one described above, the time for heating the heat exchanger (2) is shortened. Thereby, there is no inconvenience that an excessive heat load is applied to the heat exchanger (2).

The best mode for carrying out the present invention will be described below with reference to the accompanying drawings.
The water circuit and gas circuit of the water heater according to the embodiment of the present invention are configured in the same manner as that of FIG. Therefore, regarding the configuration of the water circuit and the gas circuit, the contents described in the “Background Art” are incorporated.

  FIG. 3 is a front view of a remote controller (6) connected to the water heater in FIG. 1 by a communication cable (not shown), and the remote controller (6) is disposed on a wall surface of a kitchen, a bathroom, or the like. The remote control (6) includes an operation button (61), a temperature setting button (64) including a temperature raising button (62) and a temperature lowering button (63), and a hot water supply set temperature set by the temperature setting button (64). A display screen (65) for displaying the operation state and the like is provided.

Next, the operation of the water heater according to the embodiment of the present invention will be described with reference to the flowchart of FIG.
The opening of the faucet (14) is monitored in step (ST1). Specifically, it is monitored whether or not the detected flow rate Q0 by the flow rate sensor (15) is 2.7 L / min or more, which is the minimum operating flow rate. Here, the minimum operating flow rate means a flow rate larger than the flow rate at which hot water having a temperature exceeding the hot water supply set temperature is supplied to the faucet (14) even if the gas burner (5) is burned at the minimum combustion amount.

  Next, in step (ST2), the detected temperature T0 of the hot water temperature sensor (10) is stored as the pre-ignition temperature TA, and then in step (ST3), the timer C incorporated in the control device (not shown) is set to “0”. At the same time, the slow ignition control is executed. Here, the slow ignition control is proportional to the gas so that the gas supply amount W to the gas burner (5) becomes a slow ignition gas amount W1 suitable for smooth ignition of the gas burner (5), as shown in FIG. In this control, the opening of the valve (51) is set, and in this state, an ignition spark is continuously emitted from the ignition electrode (52) to the flame outlet of the gas burner (5). This slow ignition control is continued for 1 second, and the gas burner (5) starts to burn.

  Next, in step (ST4), based on the detected flow rate Q0 of the flow rate sensor (15), the incoming water temperature sensor (18), and the hot water supply set temperature set by the temperature setting button (64) of the remote control (6), A necessary combustion amount for supplying the hot water at the hot water supply set temperature to the faucet (14) is calculated, and a gas having a combustion gas amount W2 corresponding to the necessary combustion amount is supplied to the gas burner (5).

Next, the standby time A is set according to the detected flow rate Q0 of the flow rate sensor (15). Specifically, if the detected flow rate Q0 is less than 5 L / min, the standby time A is set to 10 seconds in steps (ST5) and (ST6). In this state, the combustion gas amount W2 of the gas burner (5) is set to a level indicated by an imaginary line in FIG. On the other hand, if the detected flow rate Q0 is 5 L / min or more and less than 7 L / min, the standby time A is set to 7 seconds (see steps (ST7) and (ST8)), and the detected flow rate Q0 is 7 L / min or more. In step (ST9), the standby time A is set to 5 seconds. When the standby time A is 5 seconds, the combustion gas amount W2 of the gas burner (5) is set to a level indicated by a solid line in FIG. 2, for example. In this embodiment, the standby time A is set to the same time as the time required for the hot water heated by the heat exchanger (2) to reach the hot water temperature sensor (10). Has been. However, the standby time A may be set longer than the “time required to reach”.
Thus, the hot water heated by the heat exchanger (2) according to the detected flow rate Q0 of the flow sensor (15) is necessary for reaching the hot water temperature sensor (10) installation part. The waiting time A equal to or longer than the time is set.

  Next, execute step (ST10), and wait for the timer C (see step (ST3)) set to “0” when the gas burner (5) is ignited to exceed the set standby time A, and then In step (ST11), the detected temperature T0 of the hot water temperature sensor (10) is stored as the post-ignition temperature TB.

  Next, when it is confirmed in step (ST12) that “post-ignition temperature TB−pre-ignition temperature TA” is 5 ° C. or less which is a reference temperature difference, the hot water heated by the heat exchanger (2) is heated. However, even if the standby time A elapses, it is determined that the hot water temperature sensor (10) is not reached. In such a case, it is determined that the heated zone (1a) is clogged between the branch point (12) of the bypass passage (3) and the junction (13) in the water passage (1). In step (ST13), the gas burner (5) is extinguished, and an error message such as “Clogged water passage” is displayed on the display screen (65) of the remote controller (6).

  On the other hand, when it is confirmed in step (ST12) that “post-ignition temperature TB−pre-ignition temperature TA” exceeds 5 ° C., the hot water heated in the heat exchanger (2) portion becomes the standby time A. It is determined that the hot water temperature sensor (10) has been disposed within, and in such a case, it is determined that the heated area (1a) is not clogged. In step (ST14), it is monitored whether the faucet (14) is closed and the detected flow rate Q0 of the flow rate sensor (15) is less than 2.7 L / min. The detected flow rate Q0 is 2.7 L / min. In the above case, heat exchange is performed by the hot water mixer (4) so that the detected temperature of the mixed water temperature sensor (11) approaches the hot water supply set temperature (the temperature set by the temperature setting button (64) of the remote control (6)). The mixing ratio of hot water from the vessel (2) and cold water from the bypass (3) is set (see step (ST15)). If the hot water temperature detected by the incoming water temperature sensor (18) and the hot water set temperature set by the temperature setting button (64) of the remote control (6) are constant, the amount of hot water change (opening of the faucet (14)) As the required combustion amount of the gas burner (5) increases or decreases with the change), the gas supply amount W also increases or decreases, but the mixing ratio of hot water and cold water by the hot water mixer (4) does not change. Accordingly, when the detected flow rate Q0 of the flow rate sensor (15) increases or decreases with the change in the hot water supply amount, the flow rate of the heated area (1a) passing through the heat exchanger (2) also increases or decreases in the same manner.

On the other hand, when it is confirmed in step (ST14) that the faucet (14) is closed and the detected flow rate Q0 of the flow rate sensor (15) is less than 2.7 L / min, in step (ST16), the gas burner (5) Extinguish the fire.
In this case, when supplying a large amount of hot water with the opening of the faucet (14) increased, the detected flow rate Q0 of the flow rate sensor (15) also increases, and the hot water heated by the heat exchanger (2) becomes hot water temperature sensor ( The time required to reach the disposition part 10) is shortened. In this case, according to the present embodiment, the standby time A is shortened as the detected flow rate Q0 is increased by steps (ST5) to (ST9) in FIG. Therefore, if the heated area (1a) passing through the heat exchanger (2) is clogged during hot water supply with a large opening of the faucet (14), the standby time A is set longer than the minimum hot water supply. Compared to the conventional one, the time for which the heat exchanger (2) is heated by the gas burner (5) is shortened. Thereby, there is no inconvenience that an excessive heat load is applied to the heat exchanger (2).

  Also, when the detected flow rate Q0 of the flow rate sensor (15) is 7 L / min or more, for example, after ignition with the slow ignition gas amount W1, the gas burner (5) burns with the combustion gas amount W2 larger than the slow ignition gas amount W1 To do. Therefore, the heat generated when the heated zone (1a) is clogged only while the gas burner (5) burns with the slow ignition gas amount W1 as compared with the case where ignition is performed with the combustion gas amount W2 greater than the slow ignition gas amount W1. Overheating of the exchanger (2) can be suppressed. Therefore, the heat load applied to the heat exchanger (2) can be further reduced.

[Others]
1. In the above embodiment, the standby time A is increased stepwise as the detected flow rate Q0 of the flow sensor (15) increases. However, the standby time A is increased continuously as the detected flow rate Q0 increases. Also good.
2. In the above embodiment, the flow sensor (15) is disposed upstream of the branch point (12) of the water passage (1) and the bypass passage (3), but the water passage (1) and the bypass passage (3) A flow sensor (15) may be disposed downstream of the junction (13).
3. In the above embodiment, the hot and cold water mixer (4) is disposed at the junction (13) of the water passage (1) and the bypass (3). On the other hand, a control valve that sets the distribution ratio of the water supplied to the heat exchanger (2) and the bypass passage (3) at the branch point (12) of the water passage (1) and the bypass passage (3) is mixed with hot water. It may be arranged in place of the vessel (4). In this case, the detection temperature of the mixed water temperature sensor (11) is set by the temperature setting button (64) by setting the distribution ratio of the supply water to the heat exchanger (2) and the bypass (3) with the control valve. Control to match the set hot water temperature. In this case, the “control valve” corresponds to a “hot water mixer” which is the above-mentioned specific matter of the invention.

Schematic of a water circuit and a gas circuit of a bypass mixing type water heater that is the subject of the present invention Graph showing the change over time of the combustion amount of the gas burner (5) Front view of remote control (6) The flowchart explaining the hot_water | molten_metal supply operation | movement of the bypass mixing type water heater which concerns on embodiment of this invention.

Explanation of symbols

(1) ・ ・ ・ Waterway
(2) ・ ・ ・ Heat exchanger
(3) ... Bypass
(4) ・ ・ ・ Hot water mixer
(5) ・ ・ ・ Gas burner
(10) ... Hot water temperature sensor
(12) ・ ・ ・ Branching point
(13) ... Confluence
(15) ... Flow sensor

Claims (1)

A water passage (1) in which a heat exchanger (2) and a hot water temperature sensor (10) heated by a gas burner (5) are arranged in this order from the upstream side;
A bypass passage (3) connecting the upstream portion of the heat exchanger (2) and the downstream portion of the hot water temperature sensor (10) in the water passage (1),
A flow rate sensor (15) for detecting a flow rate upstream of the branch point (12) of the bypass channel (3) or downstream of the junction (13) in the water flow channel (1);
A hot water mixer (4) that adjusts cold water supplied from the bypass passage (3) and hot water from the heat exchanger (2) to a hot water at a hot water set temperature by mixing the water at a predetermined ratio. A vessel,
When the flow sensor (15) detects a preset burner ignition flow rate, the gas burner (5) is ignited,
The difference between the post-ignition temperature detected by the hot water temperature sensor (10) after a predetermined waiting time after the ignition and the pre-ignition temperature detected by the hot water temperature sensor (10) before the ignition is a reference temperature. In the case of the difference or less, in the water heater, it is determined that the heated area (1a) sandwiched between the junction (12) and the junction (13) of the water passage (1) is clogged.
The waiting time is shortened as the detected flow rate of the flow rate sensor (15) is increased, and hot water heated by the heat exchanger (2) is disposed in the hot water temperature sensor (10). Bypass mixing type water heater set more than the time required to reach the section.

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