JP2020008178A - Hot water server - Google Patents

Abstract

To solve a problem in a hot water server in which flow rate flowing through a heat exchanger is detected, a gas burner is ignited when the flow rate reaches a predetermined ignition flow rate, and the gas burner is automatically turned off when the flow rate becomes lower than a predetermined fire extinguishing flow rate, that in such hot water server, although a sufficiently large value is set as the predetermined ignition flow rate relatively to the predetermined fire extinguishing flow rate so that any chattering does not occur upon turning on/off the gas burner even if feed water pressure fluctuates, a problem occurs that the gas burner is not ignited unless the flow rate reaches the ignition flow rate upon starting charge of hot water under a case where a large value is set as the ignition flow rate.SOLUTION: Fluctuations in feed water pressure are detected, and when the fluctuations in feed water pressure are small, correction is made to bring the ignition flow rate closer to the fire extinguishing flow rate.SELECTED DRAWING: Figure 4

Description

  The present invention includes a flow rate sensor for detecting the amount of hot water, an ignition flow rate at which the gas burner ignites by increasing a flow rate detected by the flow rate sensor when the gas burner is extinguished, and a fire extinguishing method in which the gas burner is extinguished by reducing the flow rate The present invention relates to a hot water supply device set to a flow rate different from the flow rate.

  At the end of the hot water supply pipe that supplies hot water from the hot water supply device, a hot water outlet such as a curan is provided. When the hot water outlet such as the curan is closed and the flow from the hot water supply to the hot water is zero, the gas burner in the hot water supply is in a fire extinguishing state. As described above, the tap is opened at the tapping portion from the state where the flow rate is zero, the flow rate increases, and when the flow rate reaches the preset ignition flow rate, the gas burner is ignited and the cold water from the water pipe is heated. It becomes hot water and is supplied to the hot water outlet.

  Conversely, from the state where hot water is supplied to the tapping section with the gas burner ignited, when the tapping section is closed and the flow rate is reduced, the gas burner is turned off when the flow rate decreases to a preset extinguishing flow rate. Fire extinguished.

  If the ignition flow rate and the fire extinguishing flow rate are set to the same flow rate value, when hot water is supplied in a state where the flow rate is close to the flow rate value, the flow rate fluctuates due to the fluctuation of the pressure of the cold water in the water pipe. Then, the gas burner is in a chattering state in which point fire extinguishing is repeated even though the opening amount in the hot water supply unit is not changed. In order to avoid such a chattering state, there is known an apparatus in which the ignition flow rate is set to a value larger than the fire extinguishing flow rate to set a hysteresis between the ignition flow rate and the fire extinguishing flow rate (for example, see Patent Document 1). ).

JP-A-6-50604 (paragraph 0003)

  In the conventional hot water supply device, when the hysteresis is set, the pressure is set on the assumption that the analog pressure supplied from the water pipe is constant. However, there are cases where a large number of water supply pipes for supplying cold water to other hot water supply apparatuses are connected to the water supply pipe for supplying cold water to the hot water supply apparatus, and when the other hot water supply apparatuses operate, the water supply pipes are supplied. The pressure of the cold water drops. In addition, there are a plurality of other hot water supply devices that operate, and when the number of the hot water supply devices that operate changes, the water pressure of the cold water supplied from the water supply pipe also changes with the change. As described above, the ignition flow rate is set to a relatively larger flow rate than the fire extinguishing flow rate in consideration of the fluctuation of the water pressure of the chilled water supplied from the water supply pipe.

  However, when the ignition flow rate is far away from the fire extinguishing flow rate, the opening amount of the tapping part is gradually opened, and even if the flow rate is increased, it does not easily reach the ignition flow rate, and a considerable amount of cold water flows out of the tapping part. A problem that hot water is not discharged until the temperature rises.

  In view of the above problems, an object of the present invention is to provide a hot water supply apparatus that can start a hot water supply by igniting a gas burner as quickly as possible.

  A hot water supply apparatus according to the present invention for solving the above-described problems is a hot water supply apparatus that heats cold water supplied from a water pipe by a gas burner and taps the hot water as hot water. When the flow rate detected by the flow rate sensor reaches zero and the flow rate detected by the flow rate sensor reaches the ignition flow rate, the gas burner is ignited to heat the cold water, and the flow rate detected by the flow rate sensor from the combustion state of the gas burner decreases. And, when reaching the fire extinguishing flow rate, the gas burner is configured to extinguish the fire, the ignition flow rate is set to a value larger than this fire extinguishing flow rate, and in a hot water supply device that sets a hysteresis between the ignition flow rate and the fire extinguishing flow rate, Detecting the water pressure of the chilled water supplied from the water pipe, and when a fluctuation value of the detected water pressure of the chilled water is smaller than a predetermined value, Fire flow and performs a correction close to the fire extinguishing flow.

  By providing the above pressure sensor, the pressure of the chilled water supplied from the water pipe is detected, and when the pressure of the chilled water is stable, the ignition flow rate is brought close to the extinguishing flow rate, from opening to the ignition of the gas burner. Time was shortened.

  It should be noted that the correction of the ignition flow rate needs to be performed at the start of the next hot water supply. Therefore, the correction of the ignition flow rate is performed after the flow rate detected by the flow rate sensor falls below the fire extinguishing flow rate and the gas burner is extinguished.

  By the way, when the pressure fluctuation of the chilled water is small and the pressure fluctuation of the chilled water becomes large after the correction for bringing the ignition flow rate close to the extinguishing flow rate, it is necessary to return the ignition flow rate to the original flow rate. Therefore, when the fluctuation value of the water pressure of the cold water increases, the correction is made so that the ignition flow is separated from the fire extinguishing flow.

  It is desirable that the above-described correction to the ignition flow rate be continued even when hot water supply is started again after a power failure or the like. Therefore, the value of the ignition flow rate is stored in a nonvolatile memory, and the value of the ignition flow rate stored in the nonvolatile memory is read out when the power is turned on.

  As is apparent from the above description, the present invention sets the ignition flow rate to a value larger than the fire extinguishing flow rate and sets the pressure fluctuation value of the chilled water supplied from the water pipe when the hysteresis is set between the two. Is small and stable, a correction is made to reduce the hysteresis. As a result, the time from the start of hot water supply to the ignition of the gas burner is shortened, and the usability can be improved.

The figure which shows the structure of one Embodiment of this invention. The figure which shows the relationship between the amount of tapping of the tapping part and the flow rate Flow chart showing hot water control Flow chart for correcting ignition flow rate

  Referring to FIG. 1, reference numeral 1 denotes a hot water supply device, which includes a heat exchanger 2 therein. Cold water from the water pipe 3 is guided to the heat exchanger and is heated by the gas burner 11 so that the cold water becomes hot water and is supplied from the hot water supply pipe 21 to the hot water supply unit 4 such as a curan. Between the water pipe 3 and the heat exchanger 2, a flow sensor 22 for detecting the flow rate of the cold water flowing through the heat exchanger 2 and a pressure sensor 23 for detecting the water pressure of the cold water are provided.

  Referring to FIG. 2, the amount of plugging in hot water supply unit 4 and the flow rate flowing out of hot water supply unit 4, that is, the flow rate detected by flow rate sensor 22, are in direct proportion as shown by straight line L1. When the flow rate increases from zero to the ignition flow rate F1 along the straight line L1, the gas burner 11 is ignited. When the flow rate further increases, the heating power of the gas burner 11 is adjusted by feedback control using a temperature sensor (not shown) that detects a hot water supply temperature. When the opening amount in the hot water supply unit 4 is reduced and the flow rate is reduced, the gas burner 11 continues combustion even when the flow rate falls below the ignition flow rate F1. When the flow rate falls below the fire extinguishing flow rate E1, the gas burner 11 is extinguished there.

  When the water pressure of the chilled water supplied from the water pipe 3 decreases, the relationship between the opening amount and the flow rate in the hot water supply unit 4 changes from the straight line L1 to the straight line L2. Then, the opening amount corresponding to the ignition flow rate changes from ignition 1 to ignition 2 of F2. Similarly, the opening amount corresponding to the fire extinguishing flow rate changes from fire extinguishing 1 to fire extinguishing 2. As described above, the ignition flow rate is set to a value larger than the fire extinguishing flow rate so that the opening amount of the ignition flow rate exceeds the opening amount of the fire extinguishing flow rate even if the water pressure of the cold water changes. However, when the water pressure of the cold water is stable without fluctuating, there is no problem even if the ignition flow rate approaches the fire extinguishing flow rate.

  Referring to FIG. 3, the control shown in this figure is almost the same as the conventional control. First, detection by the pressure sensor 23 is started (S11). Thereafter, the flow waits until the flow rate detected by the flow rate sensor 22 exceeds the ignition flow rate, and if it exceeds, the gas burner 11 is ignited (S12, S13). Then, the gas burner 11 continues to detect whether or not the flow rate drops to or below the fire extinguishing flow rate during combustion (S14), and extinguishes the gas burner 11 if the flow rate falls below the fire extinguishing flow rate (S15).

  A feature of the present invention is to correct the ignition flow rate. Referring to FIG. 4, a pressure fluctuation value V is calculated from the pressure of the cold water detected by the pressure sensor 23 (S21). The calculation of the pressure fluctuation value V is not limited to a specific calculation method, and an appropriate calculation method may be adopted according to the purpose.

  If the pressure fluctuation value V calculated in step S21 is smaller than a preset reference pressure fluctuation value V1, that is, if the pressure fluctuation is small, the ignition flow rate is reduced to approach the fire extinguishing flow rate (S23). Conversely, if the calculated pressure fluctuation value V is larger than the reference pressure fluctuation value V1, the ignition flow is reset to a preset initial position (S25). Then, the ignition flow rate value determined in S23 or S25 is stored in the EEPROM which is a nonvolatile memory (S24). As described above, the pressure fluctuation value is always corrected. However, after the gas burner 11 is extinguished in S15 shown in FIG. 3, when the flow rate increases again and the gas burner 11 is ignited, the nonvolatile memory ( The determination in S12 is performed using the ignition flow rate value stored in the EEPROM.

  As described above, the ignition flow rate is corrected when the gas burner 11 is extinguished and then reignited. Even when the gas burner 11 extinguishes due to, for example, a power failure, the corrected ignition flow rate is stored in the nonvolatile memory. Therefore, when determining the ignition flow rate in S12, the ignition flow rate value stored in the nonvolatile memory as described above is used.

  By the way, in the above-described embodiment, the pressure sensor 23 in a narrow sense is used to detect the water pressure of the cold water, but any means that can detect the water pressure of the cold water may be used.

  The present invention is not limited to the above-described embodiment, and various changes may be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Hot-water supply apparatus 2 Heat exchanger 3 Water pipe 4 Hot-water supply part 11 Gas burner 22 Flow rate sensor 23 Pressure sensor

Claims (4)

  A hot water supply device for heating cold water supplied from a water pipe by a gas burner and tapping the hot water as hot water.The hot water supply device includes a flow rate sensor for detecting a hot water quantity, and the flow rate sensor detects when the hot water quantity is zero and the gas burner is extinguished. When the flow rate reaches the ignition flow rate, the gas burner is ignited to heat the cold water, and the flow rate detected by the flow rate sensor decreases from the combustion state of the gas burner, and extinguishes the gas burner when it reaches the fire extinguishing flow rate. The ignition flow rate is set to a value larger than the fire extinguishing flow rate, and in a water heater that sets hysteresis between the ignition flow rate and the fire extinguishing flow rate, the pressure of the chilled water supplied from the water pipe is detected, When the detected fluctuation value of the water pressure of the cold water is smaller than a predetermined value, it is preferable that the ignition flow is corrected to approach the fire extinguishing flow. Hot water supply apparatus according to symptoms.   The hot water supply apparatus according to claim 1, wherein the correction of the ignition flow rate is performed after a flow rate detected by the flow rate sensor is lower than a fire extinguishing flow rate and the gas burner is extinguished.   The hot water supply apparatus according to claim 2, wherein when the fluctuation value of the water pressure of the cold water increases, the ignition flow rate is corrected in a direction away from the fire extinguishing flow rate.   4. The method according to claim 1, wherein the value of the ignition flow rate is stored in a nonvolatile memory, and the value of the ignition flow rate stored in the nonvolatile memory is read out when the power is turned on. A hot water supply device according to item 1.

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