JP3355031B2 - Water heater - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for opening a hydraulic automatic gas valve to supply a fuel gas to a gas burner when the amount of water supplied to a heat exchanger becomes a predetermined value or more, and for igniting by a spark from an ignition electrode. To a hot water supply device.

[0002]

2. Description of the Related Art This type of hot water supply apparatus is disclosed in
Japanese Patent Application Laid-Open No. 178562/1992 discloses a method in which a hydraulic automatic gas valve and a safety valve are opened in series when the displacement of a movable member that is displaced in accordance with the amount of water supplied to a heat exchanger is equal to or greater than a predetermined value. In the gas supply path. In this technology, when the amount of water supply increases, the safety valve is opened by using a water flow detection switch that is turned on after the hydraulic automatic gas valve is opened, and at the same time, a spark is generated in the ignition electrode to operate the gas burner, and When the amount of water supply decreases, the safety valve is closed using the above-mentioned water flow detection switch before the automatic water pressure gas valve closes, and the displacement of the movable member temporarily decreases due to fluctuations in water supply pressure and then increases. In this case, unburned gas is prevented from being released.

[0003]

In the above-mentioned prior art, when the water supply pressure is reduced to near the minimum usable water heater, the rising speed of the displacement of the movable member is reduced, and the water flow detection switch is turned on. This increases the time from the opening of the faucet to the ignition of the gas burner and the start of hot water, which increases the time required for the igniter to operate and for the safety valve to open. When the tapping is temporarily stopped due to a drop in the supply water pressure or the like during use or when tapping is performed again, there is a problem that the drop in tapping temperature increases and the time required for the tapping temperature to rise is slow.

An object of the present invention is to solve such a problem.

[0005]

SUMMARY OF THE INVENTION A hot water supply apparatus according to the present invention includes a movable member which is displaced in accordance with the amount of water supplied to a heat exchanger, and which is opened when the displacement of the movable member exceeds a predetermined value. A gas valve and a safety valve are provided in series in a gas supply path to a gas burner, and the fuel gas ejected from the gas burner is ignited by an igniter via an ignition electrode, and the displacement of the movable member increases. In this case, the igniter is actuated when the value becomes equal to or greater than a first value equal to or less than the predetermined value, and the safety valve is subsequently opened. When the displacement of the movable member decreases, the second value equal to or more than the predetermined value is used. The safety valve is closed when the value becomes equal to or less than the value.

[0006]

[Function] In the state where the water supply to the heat exchanger is not performed,
There is no displacement of the movable member and the safety valve and the automatic hydraulic gas valve are closed. When the water supply to the heat exchanger is started, the displacement of the movable member increases in accordance with the increase in the amount of water supply, first the igniter is activated, then the safety valve is opened, the automatic hydraulic gas valve is opened, and the gas burner is opened. The jetted fuel gas is ignited by a spark generated at the ignition electrode. Thereby, the water supply to the heat exchanger is heated and discharged. If the displacement of the movable member decreases due to a decrease in the amount of water supplied to the heat exchanger or a decrease in the water supply pressure, the safety valve is closed before the automatic hydraulic pressure gas valve is closed, and the supply of the fuel gas to the gas burner is stopped.

[0007]

FIG. 1 shows an embodiment in which the present invention is applied to an instantaneous stop-type gas instantaneous water heater. As shown in FIG. 1, this instantaneous water heater 10 is a heat exchanger 11 having a water supply pipe 12 and a tapping pipe 13 in an appliance body.
And a gas burner 42 for heating the water supply pipe 12. A water control valve section 20 is connected to the inlet side of the water supply pipe 12, and a gas control valve section 30 is connected to an inlet side of the gas supply path 16 that supplies gas to the gas burner 42. The housing is formed integrally.

The water control valve section 20 is provided with a diaphragm chamber 24 in a water supply passage therein.
A faucet diaphragm 22 is provided so as to open and close the faucet valve port 21 communicating with the primary pressure chamber 24a. The faucet diaphragm 22 is provided with a pilot valve port 22a at a central portion corresponding to the faucet valve port 21. The pilot valve port 22a penetrates the housing of the water control valve section 20 in a liquid-tight and slidable manner. The faucet pilot valve 23 attached to the tip of the spindle 23a is provided in a state where it is normally urged through a spring 23b to close the pilot valve port 22a. Faucet diaphragm 22
In addition to the pilot valve port 22a, a water supply port 22b is provided in addition to the pilot valve port 22a. When the pilot valve port 22a is closed by the faucet pilot valve 23, the water supply pressure from the water supply source via the water supply port 22b increases the water pressure of the faucet diaphragm 22. It joins the back side and keeps the faucet valve port 21 of the diaphragm chamber 24 closed to stop supplying water to the water heater. If the faucet pilot valve 23 is retracted and the pilot valve port 22a is opened, the faucet diaphragm 22 moves due to the water supply pressure, the faucet valve port 21 is opened, and the supply water flows into the primary pressure chamber 24a.

The diaphragm chamber 24 is partitioned into a primary pressure chamber 24a and a secondary pressure chamber 24b by a hydraulic diaphragm 25, and flows into the diaphragm chamber 24 from the faucet valve port 21 toward the primary pressure chamber 24a of the hydraulic diaphragm 25. A water pressure control valve 26 that adjusts the amount of water to be constant even if the water supply pressure fluctuates is supported by a spring 26a, and the flow rate of the water flowing through the water supply passage is adjusted by the water pressure control valve 26. ing. The water that has flowed into the primary pressure chamber 24a is distributed and mixed into the water supply pipe 12 and the tapping pipe 13 by a water amount adjusting and mixing valve 28 rotatably provided in the housing of the water control valve unit 20, and the water is adjusted and mixed. Mixing valve 28 to valve shaft 2
The hot water temperature is adjusted by rotating the hot water temperature adjusting lever 29 via 8a to change the distribution ratio and the amount of water to the water supply pipe 12 and the hot water pipe 13. A hot water switch 48 for detecting rotation of the valve shaft 28a is provided near the hot water temperature adjusting lever 29.

The secondary pressure chamber 24b side of the diaphragm chamber 24 communicates with a venturi pipe section 14 provided in the water supply pipe 12 via a bypass pipe 15, and the amount of water passing through the water supply pipe 12 to the heat exchanger 11. , The pressure in the secondary pressure chamber 24b becomes lower than that in the primary pressure chamber 24a.
5 and the water pressure control valve 26 move to the left in FIG. 1, the water pressure automatic gas valve 32 provided in the gas flow path of the gas control valve portion 30 is opened as described later, and the first and second water pressure control valves 26 are opened.
The water flow detection switches 44 and 45 are turned on. Reference numeral 27 denotes a drain plug for draining water from both chambers of the diaphragm chamber 24, and reference numeral 17 denotes a strainer.

The gas control valve section 30 provided in the gas supply path 16 of the gas burner 42 has a gas automatic flow valve 32 which opens and closes a valve port 32a in conjunction with the movement of the hydraulic diaphragm 25 in a gas flow path inside the gas control valve section 30; A gas governor 40 whose degree of opening is automatically adjusted according to the gas pressure supplied to the gas flow path;
An electromagnetic safety valve 31 provided near the gas inlet of the gas control valve unit 30 to prevent the outflow of unburned gas at the time of misfire, and an instrument plug 34 provided at a valve port 34a for opening and closing a gas flow path. Is provided.

When the water is not flowing through the water control valve portion 20, the water pressure automatic gas valve 32 is closed by being pressed by the valve port 32a by the spring 32b, and the gas control valve portion 30 and the water control valve portion 20 are closed. The diaphragm chamber 24 is provided via a valve shaft (movable member) 33 which slidably penetrates the housing in a liquid-tight manner.
Connected to a hydraulic diaphragm 25 in the inside. In the vicinity of the valve shaft 33, the first and second valves provided on a part of the valve shaft 33 are provided.
First and second water flow detection switches 44 and 45 which are operated by the switch operation pieces 33a and 33b, respectively, are provided. If water flows into the water control valve unit 20 and the valve shaft 33 moves, the first water flow detection switch 44 is first turned on before the hydraulic automatic gas valve 32 is opened, and the first water flow detection switch 44 is opened after the hydraulic automatic gas valve 32 is opened. The second water flow detection switch 45 is turned on.

This will be described with reference to FIG.
When the amount of water supplied to 1 increases from 0, the lift amount of the valve shaft 33 increases as shown by a solid line U, but at the position of the lift amount H at which the hydraulic automatic gas valve 32 starts to open, the spring 32
The valve is temporarily stopped due to the valve closing pressure by b. As the amount of water supply increases, the first water flow detection switch 44 sets the lift amount H smaller than H.
The switch is turned on at the position 1u, the second water flow detection switch 45 is turned on at the position of the lift amount H2u exceeding H, and the lift amount is saturated when the amount of supplied water increases. When the amount of water supplied to the heat exchanger 11 decreases, the lift amount of the valve shaft 33 decreases as indicated by a broken line D, and the second water flow detection switch 45 switches to H2u.
Lift amount H2 lower by response difference ΔH2 but higher than H
The switch is turned off at the position d, and the first water flow detection switch 44 is set to H
It turns off at the position of the lift amount H1d lower than 1u by the response difference ΔH1.

The valve body 31c of the electromagnetic safety valve 31 normally has a valve port 31a closed by a spring. Valve element 31
c is opened by opening the valve port 31a by being pushed by the valve shaft 39 as will be described later. In this state, the valve body 31c is kept open by energizing the electromagnet 31b. Pressed to close it.

A motor 35 driven by a dry battery is provided as a drive source for opening and closing the appliance stopper 34, the safety valve 31, and the faucet pilot valve 23 of the water control valve unit 20. The camshaft 36 meshed with the motor shaft via a reduction gear (not shown) has first to third cams 36a,
36b and 36c are provided. When the cam shaft 36 is rotated by the motor 35, the first cam 36a moves the spindle 23a forward and backward through the motor interlock lever 38a and the faucet opening / closing lever 38b, and opens and closes the pilot valve port 22a by the faucet pilot valve 23. To open and close the faucet valve port 21 of the water control valve section 20.

When the motor 35 rotates the camshaft 36 by a predetermined angle, the second cam 36b starts pushing the valve shaft 34b of the instrument plug 34 to open the instrument plug 34, and shortly before the camshaft 36 makes one rotation. The valve shaft 34b is retracted to close the instrument plug 34. The third cam 36c is intended to temporarily advance the valve shaft 39 of the safety valve 31 by the rotation of the motor 35, and to open the valve body 31c to the attraction position of the electromagnet 31b.

Further, these cams 36a, 36b, 36
c, two cam switches 46a and 46b for detecting whether the motor 35 has rotated to a predetermined angle or not.
(Micro switch). An operation panel (not shown) provided on the front surface of the instrument body is provided with a push button 37 of a feather touch type, and a push button 3 is provided on the back side thereof.
A start switch 49 which is turned on / off by pressing 7 is provided.

Immediately above the gas burner 42, a thermocouple 55 for confirming the operation of the gas burner 42, a frame rod 56, and an ignition electrode 57 for igniting the gas burner 42 are provided. A common dry battery (for example, 3 volts) is used as a power supply for operating the motor 35, the safety valve 31, an electronic control device 50 described below, a thermocouple circuit 51, a frame guard circuit 52, an igniter 53, and the like.

As shown in FIG. 1, the instant water heater of this embodiment is controlled by an electronic control unit 50 composed of a microcomputer. The electronic control unit 50 controls the operation of the entire instantaneous water heater, a central processing unit (CPU), a read only memory (ROM), a readable and writable memory (RAM), and exchanges data between the CPU and the outside. A thermocouple circuit 51 for confirming the combustion state of the gas burner 42 by a thermocouple 55, a frame guard circuit 52 for confirming that the gas burner 42 has generated a combustion flame 42a by a frame rod 56, and a gas burner by an ignition electrode 57. Igniter 53 and safety valve 3 igniting 42
1 is connected to the valve drive circuit. Although illustration is omitted to avoid complication, the motor 3
5. Water flow detection switches 44 and 45, cam switch 46
a, 46b, hot water switch 48 and start switch 4
9 is also connected to the electronic control unit 50. The ROM stores a control program for controlling the operation of the instantaneous water heater, and the RAM stores the tapping temperature, various detected values, and the like.

Next, the operation of the above embodiment will be described with reference to FIGS. First, when the start switch 49 is turned on by the user pressing the push button 37, the motor 35 starts operating. Camshaft 36 provided with cams 36a to 36c
Is at the 0 degree position in the operation stop position (corresponding to the operation stop state of the water heater), but when the motor 35 rotates to 80 degrees, the first cam switch 46a is turned on, and the electronic control unit 50 detects this. Then, the motor 35 is temporarily stopped. During this time, firstly, the first cam 36a is
8a, the spindle 23a is retracted via the faucet opening / closing lever 38b, and the faucet valve port 21 is opened. As a result, water is distributed and supplied to the water supply pipe 12 and the tapping pipe 13 via the primary pressure chamber 24a of the diaphragm chamber 24 and the water amount adjusting / mixing valve 28. When the amount of water supplied to the water supply pipe 12 and passing through the venturi pipe section 14 becomes equal to or more than a predetermined value, the secondary pressure chamber 2
4b, the hydraulic diaphragm 25 is moved to the position shown in FIG.
Move to the left at. By this movement, the valve shaft 33 is displaced. First, the first switch actuating piece 33
The first water flow detection switch 44 is turned on via a, and then pushed by the valve shaft 33, and the automatic hydraulic pressure gas valve 32 starts to open. The operations performed before the camshaft 36 is rotated by 80 degrees and stopped is as shown in FIG. 2, and the time required for this operation is, for example, 0.2 to 0.3 seconds.

Even if the motor 35 stops, the valve shaft 33 continues to be displaced to the left and the automatic hydraulic gas valve 32 continues to open. FIG.
The position at which the first water flow detection switch 44 is turned on is delayed if the water supply pressure to the water heater decreases, but as long as the water supply pressure is within the range of the water supply pressure at which the water heater can be operated,
There will be no delay from the stop time. When both the first water flow detection switch 44 and the first cam switch 46a are turned on, the electronic control unit 50 detects this and performs a pre-check of the operation of the frame guard circuit 52 and the frame rod 56. This is performed by operating the frame guard circuit 52 for a predetermined time t1 (for example, 0.1 second) and checking whether or not to output a detection signal of the combustion flame 42a of the gas burner 42, as shown in FIG. At this point in time before the ignition operation, since the combustion flame 32a does not exist, the flame guard circuit 52 outputs the detection signal of the combustion flame because:
This is a case where an abnormality such as a failure of the frame guard circuit 52 or a failure such as an embers in the gas combustion equipment has occurred. In such a case, the electronic control unit 50 immediately stops the operation of the water heater.

If no abnormality is found by the pre-check for a predetermined time, the electronic control unit 50 restarts the operation of the motor 35 as shown in FIG.
After 2 (for example, 0.1 seconds), the igniter 53 is operated to generate a spark on the ignition electrode 57. The time difference t2 is to prevent the peak currents due to the start of the operation of the motor 35 and the start of the operation of the igniter 53 from overlapping, and to extend the life of the power supply battery. As described above, the displacement of the valve shaft 33 continues to increase during this time, and the second water flow detection switch 45 is normally turned on via the second switch operating piece 33b around the end of the pre-check for a predetermined time. However, the timing when the second water flow detection switch 45 is turned on is delayed if the water supply pressure to the water heater decreases, and is considerably delayed (for example, about one second) near the minimum water pressure at which the water heater can operate.

The third cam 36 rotated by the motor 35
c is the valve shaft 3 after the igniter 53 starts operating.
9, the valve body 31c of the safety valve 31 is pressed to open the valve port 31.
a is opened, and the second cam switch 46b is turned on at a position where it is almost fully opened. The electronic control unit 50 detects this and applies a predetermined current to the electromagnet 31b to hold the safety valve 31 in the open state. Thereafter, the pressing of the valve body 31c by the third cam 36c via the valve shaft 39 is released. You. The motor 35 continues to rotate further, and the second cam 36b
The first cam switch 46a is turned off when it reaches a predetermined angle (305 degrees in the present embodiment) at which the instrument plug 34 is opened by pressing b, and the electronic control unit 50 stops the motor 35 upon detecting this off. I do. In this state, safety valve 3
1. Since the automatic hydraulic gas valve 32 and the instrument plug 34 are opened, the fuel gas is ejected from the gas burner 42 through the gas nozzle 41 at the tip of the gas supply path 16 and ignited by the spark generated at the ignition electrode 57. Motor 3 described above
5 is, for example, 0.6 to
0.8 seconds.

Next, the electronic control unit 50 detects that the first cam switch 46a is off, activates the frame guard circuit 52, and detects the combustion flame 42a of the gas burner 42 by the frame rod 56. When the combustion flame 42a is detected, the electronic control unit 50 stops the operation of the igniter 53. As a result, the hot water supply device is activated, and the hot water supplied from the faucet valve opening 21 is heated by the heat exchanger 11 and discharged from the hot water supply pipe 13. The operation time of the frame guard circuit 52 for detecting the combustion flame 42a is, for example, 2 seconds. If no combustion flame is detected during this time, the electronic control unit 50 stops the operation of the hot water supply device.

The hot water supply device in the above-described operating state is stopped by pressing the start switch 49 again. When the start switch 49 is pressed again, the electronic control unit 50 stops the safety valve holding current, closes the safety valve 31, and
When the rotation of the camshaft 36 reaches the operation stop position (360 degrees), the second cam switch 46b is turned off, and the electronic control unit 50 stops the motor 35. During this time, the faucet pilot valve 23 which has been pulled up via the motor interlock lever 38a and the faucet opening / closing lever 38b is moved by the spring 23b to the pilot valve port 22.
a and the faucet valve port 2 by the faucet diaphragm 22.
1 is closed to stop supplying water to the water heater, whereby the first and second water flow detection switches 44 and 45 are turned off, the automatic hydraulic pressure gas valve 32 is closed, and the appliance plug 34 is also closed. Thereby, the water heater returns to the initial stop state in the description of the operation. The time from when the start switch 49 is pressed again until the hot water supply device returns to the stop state is, for example, about 0.1 second.

The above operation will be described with reference to the chart of the lift amount of the valve shaft 33 with respect to the time shown in FIG.
7 and the start switch 49 is turned on to start the water heater, the motor 35 starts to operate, and when the faucet valve opening 21 is opened, water supply to the heat exchanger 11 is started, and the lift amount of the valve shaft 33 is increased. Begins to increase over time. As described above, the lift amount of the valve shaft 33 is temporarily stopped when it reaches the position H at which the hydraulic automatic gas valve 32 starts to be opened. However, at the time point T1 when the lift amount H1 (H1u in FIG. 4) becomes lower, the first lift amount is set. The water flow detection switch 44 is turned on. Thereby, the condition that the igniter 53 operates after a predetermined time (the above-described t1 + t2) after the first cam switch 46a is turned on after a predetermined time after the activation (when the cam shaft 36 reaches the position of 80 degrees). . The operation of the motor 35 is resumed and the igniter 53
Is activated, the safety valve 31 is opened, the camshaft 36 reaches the position of 305 degrees, and the instrument plug 34 is opened.
The fuel gas ejected from the fuel cell 2 is ignited and hot water is started. That is, in this embodiment, tapping is started substantially after a predetermined time from the start. At time T2 when the lift amount of the valve shaft 33 exceeds H and reaches H2 (H2u in FIG. 4), the second water flow detection switch 45 is turned on, but this does not affect the start time of tapping of the water heater.

As shown in FIG. 3A, a position H2 (FIG. 4) where the lift amount of the valve shaft 33 is temporarily reduced due to a change in the water supply pressure during tapping and the second water flow detection switch 45 is turned off.
H2d), the electronic control unit 50 stops the safety valve holding current, closes the safety valve 31, and
5, the motor 35 is stopped when the rotation angle of the camshaft 36 exceeds the operation stop position (360 degrees) and reaches 80 degrees and the first cam switch 46a is turned on. . During this time, the faucet valve port 21 is closed and the water supply is stopped, as in the case where the start switch 49 is pressed again to stop the operation.
4 and 45 are turned off, the automatic hydraulic gas valve 32 is closed, and the instrument plug 34 is also closed. However, since the cam shaft 36 is rotated to the position of 80 degrees, the faucet valve port 21 is opened again to supply water. Is made. Actually, when the first water flow detection switch 44 drops below the point where the first water flow detection switch 44 is turned off due to a decrease in the water supply pressure, the water supply pressure rises again, and the first water flow detection switch 44 is turned on to ignite. Water flow detection switch 44
When the water supply pressure rises again in a state where the water pressure does not turn off (the first water flow detection switch 44 remains on), the ignition is performed when the second water flow detection switch 45 is turned on. Then, the pre-check by the frame guard circuit 52 described above is performed, the igniter 53 is continuously operated, the safety valve 31 and the instrument plug 34 are opened, and the lift amount of the valve shaft 33 exceeds H, and the hydraulic automatic gas valve 32 is opened. Then, the gas burner 42 is immediately ignited.

When the water pressure from the water source drops,
The rising speed of the lift amount of the valve shaft 33 shown in FIG.
The slopes of the ascending characteristics decrease, and the times T1 and T2 at which the first and second water flow detection switches 44 and 45 are turned on are both delayed. When the water supply pressure from the water supply source is reduced to near the minimum usable water heater, the lift amount H2 at which the second water flow detection switch 45 is turned on approaches the saturation position of the characteristic curve, so the delay of the time point T2 is delayed. Is larger than the delay at time T1. For this reason, the safety valve is opened by using a water flow detection switch (corresponding to the second water flow detection switch 45 of the present embodiment) which is turned on after the automatic water pressure gas valve is opened, and at the same time, a spark is generated in the ignition electrode, and the gas burner is opened. In the prior art for operating the water heater, the time from the start to the start of hot water supply becomes longer, and especially when the water supply pressure from the water supply source is reduced to near the minimum available for the hot water supply device, this time is greatly increased. For this reason, the drop of hot water temperature at the time of intermittent use becomes large, and the time until hot water temperature rises is delayed. On the other hand, in this embodiment, as described above, the time point T2 does not affect the hot water supply start timing, and the camshaft 36 reaches the position at 80 degrees at the time point T1 within the range of the water supply pressure at which the hot water supply device can operate. Since there is no delay from the timing, even if the water supply pressure decreases as described above, the time from the start to the start of hot water supply does not become long. Therefore, the drop of the hot water temperature during intermittent use is reduced, and the hot water temperature rises faster.

In the case where the tapping pressure is lowered during tapping and tapping is temporarily stopped, the prior art having only a water flow detection switch corresponding to the second water flow detection switch 45 of the present embodiment has a valve shaft. Since the operation of opening the safety valve and igniting the gas burner is not performed until the lift amount of the valve 33 exceeds the position corresponding to H2, even if the water supply pressure recovers, the time until the tapping restarts becomes longer as described above. If the pressure of the water supply from the water supply drops close to the minimum limit at which the device can be used, this time increase will be significant. For this reason, the drop of the hot water temperature due to such a temporary stop becomes large. On the other hand, in the present embodiment, if the lift amount of the valve shaft 33 recovers to the position H at which the hydraulic automatic gas valve 32 opens, the ignition of the gas burner 42 is stopped within a predetermined time after the first water flow detection switch 44 is turned on. Therefore, even if the water supply pressure drops as described above, the time from the temporary stop of tapping to the restart of tapping does not become long. Therefore, the drop of the tapping temperature due to such a temporary stop is reduced.

The present invention is not limited to the hot water supply device of the main stop type as in the above embodiment, but can be applied to a hot water supply device of a front stop type. In this case, the faucet valve port 21, the faucet diaphragm 22 and the operating members thereof may be removed, and a hot water tap may be provided at the tip of the tapping tube 13 instead. The effect of reducing the drop in tapping temperature due to the temporary stoppage of tapping water due to fluctuations and the like is obtained.

[0031]

According to the present invention, the igniter can be operated before the hydraulic automatic gas valve is opened, and subsequently, the safety valve and the hydraulic automatic gas valve are opened to ignite the fuel gas ejected from the gas burner. Even when the feed pressure decreases and the moving member rises at a lower speed, tapping of the hot water is started immediately after the automatic hydraulic gas valve is opened. Therefore, even in such a case, the time from when the tap is opened to when tapping is started is shortened, and the drop in tapping temperature when tapping is temporarily stopped due to intermittent use or drop in water supply pressure is reduced. Can be. In addition, when the displacement of the movable member is reduced due to a change in the water supply pressure, etc., the safety valve is closed before the hydraulic automatic gas valve is closed. No combustion gas is released.

[Brief description of the drawings]

FIG. 1 is a diagram showing an overall configuration of an embodiment of a hot water supply apparatus according to the present invention.

FIG. 2 is a time chart showing the operation of each part of the embodiment shown in FIG.

FIG. 3 is an explanatory diagram of the operation of the embodiment shown in FIG. 1;

FIG. 4 is a diagram showing characteristics of a valve shaft lift amount with respect to a water supply amount to a heat exchanger.

[Explanation of symbols]

11 heat exchanger, 16 gas supply path, 31 safety valve, 3
2: Automatic water pressure gas valve, 33: movable member (valve shaft), 42:
Gas burner, 53: igniter, 57: ignition electrode.

Claims (1)

(57) [Claims] 1. A movable member that is displaced in accordance with the amount of water supplied to a heat exchanger, and a water pressure automatic gas valve that is provided in a gas supply path to a gas burner and that opens when the displacement of the movable member exceeds a predetermined value. And a safety valve provided in series with the hydraulic automatic gas valve, and an igniter for igniting fuel gas ejected from the gas burner via an ignition electrode, when the displacement of the movable member increases. The igniter is actuated when the value becomes equal to or more than the first value equal to or less than the predetermined value, and the safety valve 31 is subsequently opened. When the displacement of the movable member decreases, the second value equal to or more than the predetermined value is used. A hot water supply device comprising closing the safety valve when the following occurs.