Hot water storage type water heater

Abstract

To provide a hot water storage type water heater which can suppress a large undershoot of a can body temperature.SOLUTION: A hot water storage type water heater comprises a can body 10 for storing hot water, a combustion burner 13 for heating the can body, can body temperature detection means 21 for measuring a temperature of the can body, a first combustion mode for turning on the combustion burner 13 when a detection value of the can body temperature detection means 21 is lower than a first temperature t1, and turning off the combustion burner 13 when the detection value is equal to or higher than a second temperature t2 higher than the first temperature t1, a second combustion mode for repeating control for forcibly turning on the combustion burner 13 after the lapse of a prescribed off-time T0, and turning off the combustion burner 13 when the temperature is equal to or higher than a second temperature t2, a first timer D1 for counting a combustion time after the combustion burner 13 is turned on and up until the combustion burner is turned off, and a control part 80 for controlling the combustion of the combustion burner. When a time of the first timer D1 is equal to or longer than the first time t1, the control part 80 switches a combustion mode to the second combustion mode, and when a required finish condition is satisfied, the control part returns the combustion mode to the first combustion mode.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a storage type hot water supply device. [Background technology]

[0002] Conventionally, in this type of device, a heat-retaining operation has been performed in which the hot water in the hot water storage section is heated to an extinguishing temperature higher than a set temperature by burning a burner and exchanging heat with the combustion gas, and when the hot water temperature in the hot water storage section reaches the extinguishing temperature, the combustion of the combustion burner is stopped, and when the hot water temperature in the hot water storage section falls below an ignition temperature lower than the set temperature, the combustion burner is burned again, the hot water in the hot water storage section is heated to the extinguishing temperature, and the combustion of the combustion burner is stopped (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5431135 Summary of the Invention [Problem to be solved by the invention]

[0004] In this conventional device, a can body thermistor was installed slightly above the center of the side of the can body, and combustion began when the temperature of the hot water inside the can body measured by this can body thermistor (hereinafter referred to as the can body temperature) fell below a predetermined ignition temperature. Therefore, immediately after a large amount of hot water in the can was used, the same amount of water was supplied to the can as was used, causing the can temperature to drop suddenly. Even if the can temperature dropped below the ignition temperature and was reignited, the can temperature did not rise immediately and the temperature continued to drop, resulting in a significant undershoot from the set temperature, leaving room for improvement.

[0005] In particular, in a hot water supply device of a storage type having a small capacity of the tank body, undershoot of the tank body temperature occurs significantly.

[0006] The present invention has been made in consideration of the above background, and has an object to provide a storage type hot water supply device that can suppress a significant undershoot of the boiler body temperature. [Means for solving the problem]

[0007] The present invention has been made to achieve the above-mentioned object, and as claimed in claim 1, the invention comprises a can body for storing hot water, a combustion burner for heating the can body, a can body temperature detection means for measuring the temperature of the can body, a water inlet provided in the can body, a hot water outlet provided in the can body, a first combustion mode for turning on the combustion burner when the detection value of the can body temperature detection means is less than a first temperature and turning off the combustion burner when the detection value is equal to or greater than a second temperature higher than the first temperature, a second combustion mode for forcibly turning on the combustion burner after a predetermined off time and turning off the combustion burner when the temperature is equal to or greater than the second temperature, a first timer for measuring the combustion time from when the combustion burner is turned on to when it is turned off in the first combustion mode, and a control unit for controlling the combustion of the combustion burner, wherein the control unit switches to the second combustion mode when the time of the first timer is equal to or greater than a first time in the first combustion mode, and returns to the first combustion mode when a specified termination condition is satisfied.

[0008] In claim 2, the invention is characterized in that it further includes a second timer that measures the combustion time from when the combustion burner is turned on in the second combustion mode, and the specified termination condition is when the time of the second timer in the second combustion mode elapses a second time that is shorter than the first time, and the detection value of the can body temperature detection means is equal to or higher than the second temperature.

[0009] In a third aspect of the present invention, the control unit turns off the combustion burner when the detection value of the can body temperature detection means is equal to or higher than a third temperature that is higher than the second temperature. Effect of the Invention

[0010] According to the present invention, a storage type hot water supply device can be provided that can suppress a significant undershoot of the boiler body temperature. [Brief description of the drawings]

[0011] [Figure 1] 1 is a schematic diagram of a storage type hot water supply device according to a first embodiment of the present invention; [Diagram 2] Block diagram of a storage type hot water supply device according to a first embodiment of the present invention. [Diagram 3] Flowchart diagram of the storage type hot water supply device according to the first embodiment of the present invention. [Figure 4] FIG. 1 is a diagram for explaining the relationship between the temperature of the boiler body and the combustion burner of the storage type hot water heater according to the first embodiment of the present invention. [Diagram 5] FIG. 1 is a diagram for explaining the relationship between the temperature of the tank body and the combustion burner of a conventional hot water supply device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] A first embodiment of the present invention will be described with reference to FIGS.

[0013] Reference numeral 1 denotes a storage type hot water supply device not equipped with a mixing valve, which stores a certain amount of hot water inside and has a combustion burner 13 which receives a supply of combustion air from a combustion fan 14 to burn a fuel (kerosene or gas), a heat exchanger 20 which recovers heat from the combustion gas generated by the combustion of the combustion burner 13 and heats the hot water, an exhaust chamber 17 which is installed above the heat exchanger 20 and collects the combustion gas after passing through the heat exchanger 20, and an exhaust pipe 18 which discharges the combustion gas after passing through the exhaust chamber 17 outside the appliance.

[0014] The heat exchanger 20 is composed of a cylindrical can body 10 which stores a certain amount of hot water inside, a combustion chamber 15 formed inside the lower part of the can body 10 where combustion takes place with the combustion burner 13, and a number of smoke tubes 16 which connect the combustion chamber 15 to the exhaust chamber 17 and allow the combustion gas generated by the combustion of the combustion burner 13 to pass through.

[0015] Reference numeral 21 denotes a can body temperature detection means, such as a thermistor, which is attached to approximately the center of the top and bottom of the can body 10 and detects the temperature of the hot water. A water supply port 22 is provided on the side surface of the lower part of the can body 10, and a water supply pipe 11 is connected to the water supply port 22, and a pressure reducing valve 12 is provided midway in the water supply pipe 11.

[0016] Furthermore, a hot water outlet 23 is provided on the side surface of the can body 10 for discharging the hot water stored in the can body 10 at the top of the can body 10, and the hot water outlet 23 is provided with a hot water tap 35 at its end and a hot water pipe 34 branching off midway and equipped with a pressure relief valve 38. Reference numeral 80 denotes a control unit consisting of a microcomputer that controls the combustion of the combustion burner 13, and is connected to be able to communicate with a remote control 90 installed outside the appliance.

[0017] The control unit 80 is connected to a can body temperature detection means 21 such as a can body thermistor on the input side, and to a combustion burner 13 and a combustion fan 14 on the output side. The remote control 90 is also provided with an operation switch 91 .

[0018] The control unit 80 is capable of executing a first combustion mode in which the combustion burner 13 is turned on when the detection value of the can body temperature detection means 21 is less than a first temperature t1, and turned off the combustion burner 13 when the detection value is equal to or greater than a second temperature t2 higher than the first temperature t1, and a second combustion mode in which the combustion burner 13 is forcibly turned on after a predetermined off time T0 (e.g., 5 seconds), and the combustion burner 13 is turned off when the temperature is equal to or greater than the second temperature t2, repeating this control. The control unit 80 also has a first timer D1 that measures the combustion time from when the combustion burner 13 is turned on to when it is turned off in the first combustion mode, and a second timer D2 that measures the combustion time from when the combustion burner 13 is turned on in the second combustion mode.

[0019] The control unit 80 switches to the second combustion mode when the time of the first timer D1 in the first combustion mode is equal to or greater than the first time T1 (e.g., 60 seconds), and returns to the first combustion mode when a specified end condition is satisfied. Here, the specified termination condition is when the time of the second timer D2 in the second combustion mode elapses a second time T2 (e.g., 30 seconds) that is shorter than the first time T1, and the detection value of the can body temperature detection means 21 is equal to or higher than the second temperature t2. In addition, the control unit 80 is capable of executing a forced extinguishing mode in which the combustion burner 13 is turned off to prevent overheating when the detection value of the can body temperature detection means 21 reaches or exceeds a third temperature t3 (e.g., 45°C), which is a forced extinguishing temperature higher than the second temperature t2.

[0020] Next, the operation of the first embodiment of the present invention will be described.

[0021] First, when the operation switch 91 provided on the remote control 90 is turned on, the control unit 80 compares the detection value of the can body temperature detection means 21 with a first temperature t1 (e.g., 30°C), which is an ignition temperature lower than the set temperature t0 (e.g., 35°C) set by the temperature setting means 92, and when the detection value of the can body temperature detection means 21 is lower than the first temperature t1, it turns on the combustion burner 13 to start combustion. Then, the temperature of the hot water in the boiler body 10 increases due to the combustion of the combustion burner 13.

[0022] In addition, the detection value of the can body temperature detection means 21 is compared with a second temperature t2 (e.g., 40°C), which is an extinguishing temperature equal to or higher than the set temperature t0, and when the detection value of the can body temperature detection means 21 is higher than the second temperature t2, the combustion burner 13 is turned off to stop combustion. Then, the temperature inside the can body 10 gradually drops.

[0023] The details will be explained based on FIG. First, the control unit 80 starts operation in the first combustion mode described below. That is, if the detection value of the can body temperature detection means 21 is less than the first temperature t1, which is the ignition temperature (step S1), combustion in the combustion burner 13 is started (step S2), and if the detection value is equal to or greater than the first temperature t1, which is the ignition temperature, the system waits until the temperature falls below the first temperature t1. Then, when the combustion burner 13 starts combustion (step S2), the first timer D1 is started (step S3). If the detection value of the boiler body temperature detection means 21 is equal to or higher than the second temperature t2, which is the extinguishing temperature (step S4), the combustion burner 13 is extinguished (step S5). When the time counted by the first timer D1, which measures the time from the start of ignition to extinguishing, is less than the first time T1, the process proceeds to step S1 and the first combustion mode is continued. If the first time T1 is reached or exceeded, the combustion mode is switched to the second combustion mode (step S6).

[0024] Next, the second combustion mode will be described. In the second combustion mode, in step S7, the combustion burner 13 is extinguished immediately before (extinguishing in step S5 and in step S14 described later), and after a predetermined off time T0 (e.g., 5 seconds) has elapsed, combustion of the combustion burner 13 is resumed in step S8. Then, when the combustion of the combustion burner 13 is resumed (step S8), the second timer D2 is started (step S9).

[0025] Then, when the time elapsed by the second timer D2 exceeds the second time T2 (step S11) and the detection value of the can body temperature detection means 21 is less than the second temperature t2 (step S12), the process transitions to step S13 and waits until the detection value of the can body temperature detection means 21 becomes equal to or greater than the second temperature t2 (step S13). Then, when the detection value of the can body temperature detection means 21 becomes equal to or higher than the second temperature t2, it takes a time of equal to or higher than the second time T2 to reach the second temperature t2, so in order to continue the second combustion mode, the combustion burner 13 is temporarily extinguished (step S14), and the second combustion mode is continued from step S7.

[0026] If the time elapsed by the second timer D2 exceeds the second time T2 (step S11) and the detection value of the can body temperature detection means 21 is equal to or higher than the second temperature t2 (step S12), the condition for terminating the second combustion mode is met, the combustion burner 13 is turned off (step S15), and the process transitions to step S1 and returns to the first combustion mode.

[0027] If the time elapsed by the second timer D2 is less than the second time T2 and the detection value of the can body temperature detection means 21 becomes equal to or higher than the third temperature t3, which is the forced extinguishing temperature (step S10), the combustion burner 13 is turned off (step S16), the time during which re-ignition is not possible is extended from the normal time to allow the appliance to cool, and further, the post-purge time in which the combustion fan 14 is operated for a certain period of time to exhaust unburned gas from the combustion chamber 15 is extended from the normal time (step S17), and operation is terminated.

[0028] In the conventional technology, as shown in FIG. 5, combustion began when the temperature of the hot water in the can body 10 measured by the can body temperature detection means 21 fell below the first temperature t1, which is the ignition temperature. However, if a large amount of hot water in the can body 10 was used, the temperature inside the can body 10 dropped rapidly because the same amount of hot water was supplied to the can body 10 as was used during the pouring process. When the can body temperature fell below the first temperature t1, which is the ignition temperature, the water was re-ignited to heat the hot water in the can body 10, but the can body temperature did not rise immediately and the temperature continued to fall, resulting in a significant undershoot from the second temperature t2, leaving room for improvement.

[0029] In the present invention, when the elapsed time from the start of combustion of the combustion burner 13 to its extinguishing is equal to or longer than a first time T1 in the first combustion mode, the combustion burner 13 is forcibly turned on after a predetermined off time T0, and the combustion burner 13 is switched to a second combustion mode in which the control of turning it off at or above a second temperature t2 is repeated. When the time of the second timer D2 in the second combustion mode elapses a second time T2 that is shorter than the first time T1 and the detection value of the can body temperature detection means 21 is equal to or higher than the second temperature t2, the second combustion mode is terminated and the first combustion mode is returned to.

[0030] As a result, when the combustion burner 13 has a long combustion time from the start of combustion to its extinguishing, which is longer than the first time T1, it is determined that a large amount of molten metal has been discharged, and combustion is resumed before an undershoot occurs. This prevents a significant undershoot in the boiler body temperature, and as a result, a stable molten metal temperature can be obtained. In particular, even in a small storage type hot water supply device, if the elapsed time from the start of combustion of the combustion burner 13 to its extinguishing is equal to or longer than the first time T1, combustion is forcibly started again even immediately after a large amount of hot water in the boiler body 10 has been used, so that no significant undershoot occurs and a stable hot water outlet temperature can be obtained. Even if a low-output combustion burner 13 whose output cannot be adjusted is installed, combustion is resumed before the boiler body temperature drops, so no large undershoot occurs and a stable tapping temperature can be obtained.

[0031] The other configurations used in the present embodiment are presented as examples, and are not intended to limit the scope of the invention, and may be embodied in various other forms, and various omissions, substitutions, and modifications may be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, and are included in the invention and its equivalents described in the claims. [Explanation of symbols]

[0032] 1: Storage type hot water supply device 10:Can body 13: Combustion burner 21: Can body temperature detection means (can body thermistor) 22: Water supply port 23:Hot water outlet 80: Control section D1: First timer D2: Second timer T0: Off T1: First Hour T2: Second Hour t1: 1st temperature t2: 2nd temperature t3: 3rd temperature

Claims

1. A tank body for storing hot water; A combustion burner for heating the can body; A can body temperature detection means for measuring the temperature of the can body; A water supply port provided on the can body; A hot water outlet provided on the boiler body; a first combustion mode in which the combustion burner is turned on when the detection value of the can body temperature detection means is less than a first temperature, and the combustion burner is turned off when the detection value is equal to or greater than a second temperature higher than the first temperature; a second combustion mode in which the combustion burner is forcibly turned on after a predetermined off time, and the combustion burner is turned off when the temperature is equal to or higher than the second temperature; a first timer that measures a combustion time from when the combustion burner is turned on to when it is turned off in the first combustion mode; A control unit that controls combustion of the combustion burner; Equipped with The control unit is When the time of the first timer is equal to or greater than a first time in the first combustion mode, the combustion mode is switched to the second combustion mode, and when a specified end condition is satisfied, the combustion mode is returned to the first combustion mode. A storage type hot water supply device characterized by the above.

2. A second timer is further provided to measure a combustion time from when the combustion burner is turned on in the second combustion mode, The termination conditions of the above provision are: In the second combustion mode, the time of the second timer has passed a second time shorter than the first time, and the detection value of the can body temperature detection means is equal to or higher than the second temperature.

2. The storage type hot water supply device according to claim 1 .

3. The control unit is When the detected value of the can body temperature detecting means is equal to or higher than a third temperature which is higher than the second temperature, the combustion burner is turned off.

3. The storage type hot water supply device according to claim 2.

Images