JPH094921A - Hot water supplier - Google Patents

Abstract

PURPOSE: To inhibit a trouble where an abnormal instrument operation followed by remaining fire is repeated, and ensure durability of a long term use of a hot water interruption valve by employing a manual return-type remaining-fire safety device which is returned to an initial state only by a manual operation. CONSTITUTION: A heat exchanger 24 is provided on a water supply circuit 27, the heat exchanger being heated with a gas burner 23. Stagnant water in the heat exchanger 24 is detected by a high temperature detector 41 of a remaining fire safety device 4, and when the temperature of the stagnant water becomes an abnormarily high temperature, a gas supply valve 33 for supplying gas to the gas burner 23 is forcedly closed. At this time, the remaining-fire safety device 4 is constructed as a manual return type where it is returned to an initial state only by a manual operation. A hot water supply interruption valve 29 is provided on a water supply passage 27 located downstream the heat exchanger 24, which is closed when supply water in the water supply circuit 27 becomes abnormally high temperature. Hereby, inhibiting inconvenience where abnormal instrument operation followed by remaining fire is repeated, and making the hot water interruption valve 29 usable over a long period of time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water heater, and more particularly to a water heater of a type having a function of avoiding the continuation of a so-called afterglow state in which the gas burner does not extinguish even when the hot water supply is stopped.

[0002]

2. Description of the Related Art In a general water heater, a water flow detector (for example, a water flow switch or the like), a heat exchanger, and a tap water tap are sequentially provided in this order from the upstream side in the water passage circuit. A gas valve is provided in the gas circuit to the gas burner which heats the heat exchanger. When the water flow detector detects water flow in the water flow circuit that occurs when the hot water tap is opened, the gas valve is kept open and the gas burner is ignited, whereby the hot water supply operation starts.

On the other hand, in this kind of water heater, when the water flow detector malfunctions, the water flow detection signal of the water flow detector may not disappear even though the hot water tap is closed. There is a disadvantage that the so-called afterglow state in which the combustion of the gas burner continues without closing the gas valve. Therefore,
In the above water heater, an afterglow safety device such as a bimetal switch that detects the temperature when the accumulated water in the heat exchanger reaches an abnormally high temperature and shuts off the power supply for driving the gas valve is provided with an afterglow safety device. When the accumulated water in the heat exchanger is in an abnormally high temperature due to the occurrence, the gas valve is forcibly closed to maintain the gas burner in a fire extinguishing state, thereby ensuring a safe state. Further, a hot water cutoff valve that is closed when the inside of the water flow circuit becomes abnormally hot is arranged in the water flow circuit on the downstream side of the heat exchanger.
Even if the tap water tap is opened under the condition that the hot water caused by the afterglow remains in the heat exchanger, the risk of the hot water flowing out from the tap is prevented. It should be noted that the hot water shutoff valve is a heat sensitive member that deforms when the water inside the valve is in an abnormally high temperature state (for example, a coil made of shape memory alloy or shape memory resin).
Is incorporated, and the valve is driven to close in conjunction with the deformation operation of the heat-sensitive member.

However, in the above-mentioned water heater, even after the afterglow is generated and the gas burner is forcibly extinguished, if the temperature of the accumulated water in the heat exchanger decreases due to the subsequent natural heat dissipation, the afterglow safety formed of bimetal or the like. Since the apparatus automatically returns to the initial state, when the hot water tap is reopened, the gas burner burns and the hot water supply operation is started. Therefore, in such a case, an afterfire will be generated again, which causes a problem that abnormal instrument operation is repeated. In addition, when the afterglow safety device automatically returns to the initial state and repeated embers occur repeatedly, the hot water shutoff valve is activated and the hot water cutoff valve operates more frequently without noticing this. There is also a disadvantage that a heat-sensitive material such as a shape memory alloy that gives a closing valve driving force to the shutoff valve easily becomes fatigued, and long-term use of the hot water shutoff valve cannot be ensured.

The present invention has been made in view of the above point, and "The heat exchanger provided in the water flow circuit and heated by the gas burner and the temperature of the accumulated water in the heat exchanger are detected and detected. Afterglow safety device that forcibly closes the gas valve for supplying gas to the gas burner when the temperature becomes abnormally high, and water flow provided in the water flow circuit downstream of the heat exchanger and in the water flow circuit In a water heater equipped with a hot water shutoff valve that closes when the temperature rises to an abnormally high temperature ” The task is to make it usable.

[0006]

[Technical Means] A technical means of the present invention for solving the above-mentioned problem is to "adopt a manual recovery type afterglow safety device that does not recover to an initial state unless it is manually operated".

[0007]

According to the above technical means, when the afterglow occurs and the gas valve is maintained in the forced closing state, even if the accumulated water in the water passage circuit of the heat exchanger naturally lowers in temperature, it can be manually operated. The afterglow safety device will not return to the initial state unless it is done. That is, the gas valve is maintained in the closed state until the above-mentioned afterglow safety device is manually restored after repairing the failure point causing the afterglow. Therefore, even if the tap hole is opened in such a state, the gas burner will not burn.

[0008]

[Effect] The present invention has the following unique effects. After the afterglow safety device is activated, the gas burner will not return to a combustible state unless it is manually returned manually.Therefore, there is no room for an afterglow to occur even if the hot water tap is opened under such conditions. It is possible to avoid the inconvenience of repeated abnormal instrument operation accompanied by fire.

Further, since the operation of the appliance accompanied by the afterglow is not repeated, the operation frequency of the hot water cutoff valve due to the accidental opening of the hot water tap is reduced, and the shape memory alloy that gives the valve closing driving force to the hot water cutoff valve. The heat-sensitive material such as is less likely to fatigue, and the hot water cutoff valve can withstand long-term use.

[0010]

Next, an embodiment of the present invention will be described.
As shown in Fig. 1, there is a heat exchange device inside the water heater body (1).
(2), a control device (5), etc. are arranged, and the heat exchange device (2) includes a can body (21) supplied with air from an air supply fan (22) and a gas burner provided inside thereof. (23) and a heat exchanger (24) above it, and an exhaust pipe (25) is connected to the upper end of the can body (21).

A water flow circuit (27) including the heat exchanger (24)
A water flow detector (26) such as a water flow switch or a flow meter is provided near the upstream end of the heat exchanger (24), and a hot water outlet temperature sensor (28) and a hot water cutoff valve (29) are provided downstream of the heat exchanger (24). ) And taps (3) are provided in this order. As shown in FIG. 3, the hot water shut-off valve (29) has a valve body (29) between a heat sensitive coil (291) made of a shape memory alloy and a valve opening spring (290).
2) has a structure in which The heat sensitive coil (291) is kept in a contracted state at 90 ° or less, and in this state, the valve body (29) is urged by the urging force of the valve closing spring (290).
2) is kept open. Further, when the heat sensitive coil (291) comes into contact with the hot water having a temperature equal to or higher than the set temperature, the heat sensitive coil (291) is extended and the valve body (292) is closed.

Further, the water flow circuit (2
A high temperature detector (41) which outputs an abnormality detection signal when a temperature higher than a set temperature (90 ° C. in this embodiment) is detected is additionally provided in 7). The output of 41) is applied to the set input terminal of the flip-flop (42). A reset switch (43) is connected to the reset terminal of the flip-flop (42), and the output of the flip-flop (42) is connected to the L active terminal of the AND circuit (44) and the remote controller (6) described later. Is being applied to. And
In this embodiment, the high temperature detector (41), the flip-flop (42), the reset switch (43) and the AND circuit (44) correspond to the afterglow safety device (4) described in the section of technical means. are doing.

Next, in the gas circuit (31) to the gas burner (23), a proportional valve (32) and a main valve (33) corresponding to the gas valve described in the technical means section are inserted. , Each of these valves (32) (3
3) and the above-mentioned air supply fan (22) are controlled by a control device (5) incorporating a microcomputer.
Further, the output of the water flow detector (26) and the hot water temperature sensor (28) provided in the water flow circuit (27) is applied to the control device (5), and further, to the control device (5). Is connected to the remote control (6). Then, the remote control (6) has an operation switch (6
1), temperature setter (62), temperature indicator (63) and afterglow alarm (6
4) is provided, and a light emitting diode, a buzzer or the like can be adopted as the afterglow alarm (64).

The control program having the contents shown in the flow chart of FIG. 2 is stored in the microcomputer incorporated in the control device (5), and the operation of the water heater of the present embodiment will be described below with reference to FIG. To do. In the initial state, the flip-flop (42) outputs the L signal, which is applied to the L active terminal of the AND circuit (44). Therefore, in such an initial state, the main valve (33) is controlled to open and close only by the signal from the control device (5).

When it is confirmed in step (70) that the operation switch (61) is turned on, in step (71) it is monitored that the hot water tap (3) is opened. And tap tap
When (3) is opened and the water flow detector (26) outputs a water flow detection signal, the main valve (33) is opened and the air supply fan (22) is driven in step (72). Next, in step (73), an ignition device (not shown) is operated to burn the gas burner (23),
Further, the proportional valve (32) is used to control the combustion amount of the gas burner (23) so that hot water of the temperature set by the temperature setter (62) is boiled.
The opening degree of is adjusted (step (74)), whereby the hot water supply operation is started. When the hot water tap (3) is closed during this hot water supply and the water flow detection signal from the water flow detector (26) disappears (step (75)), the main valve (33) is closed at step (76). The air supply fan (22) is stopped, thereby ending the hot water supply operation.

However, if an abnormal condition occurs in which the water flow signal of the water flow detector (26) does not disappear despite the fact that the hot water tap (3) is closed during the hot water supply, the heat exchanger (24) stays in the heat exchanger (24). The temperature of the water rises above the temperature set by the temperature setter (62). Therefore, in such a case, the proportional valve is controlled by the hot water temperature control function of the controller (5) based on the output of the hot water temperature sensor (28).
Even if (32) is throttled to the minimum opening, the gas burner (23) does not completely extinguish the fire and an afterglow occurs. Then, when the accumulated water in the heat exchanger (24) rises in temperature to 90 ° C., the high temperature detector (41) outputs an abnormal signal, which causes the flip-flop (42) to go high.
A signal is output, the output of the AND circuit (44) changes to the L state, and the main valve (33) is forcedly closed. This allows the gas burner (2
3) is maintained in a fire extinguishing state and a safe state is secured. or,
The output of the flip-flop (42) is applied to the remote controller (6) to activate the afterglow alarm (64) provided in the remote controller (6), thereby notifying that an afterglow has occurred.
In addition, when the hot water tap (3) is opened and the high temperature water flows down to the hot water cutoff valve (29) with the abnormally high temperature water staying in the heat exchanger (24), With heat sensitive coil (29
1) is extended and the valve body (292) is closed. Therefore, it is possible to prevent the hot water from flowing out from the hot water tap (3).

Next, when the temperature of the accumulated water in the heat exchanger (24) drops to less than 90 ° C. due to natural heat dissipation, the abnormal signal from the high temperature detector (41) disappears. However, even if the signal of the high temperature detector (41) disappears, the output of the flip-flop (42) does not return to the L state, and the original valve (33) is maintained in the closed state. Therefore, in this state, even if the hot water tap (3) is opened again, the gas burner (23) does not burn, and there is no room for producing an afterfire when the reopened hot water tap (3) is closed.

On the other hand, the afterfire alarm (6
When 4) is activated and the occurrence of an afterfire is reported, the appliance user requests a repair company to repair the faulty part. And
Reset switch (43) when repair of defective part is completed
When is operated, the flip-flop (42) returns to the initial state, thereby returning to the initial state in which hot water can be supplied.

[Brief description of drawings]

FIG. 1 is a sectional view of a water heater according to an embodiment of the present invention.

FIG. 2 is a flowchart for hot water supply control.

FIG. 3 is a sectional view of a main part of the hot water cutoff valve (29).

[Explanation of symbols]

 (1) ・ ・ ・ Hot water heater body (2) ・ ・ ・ Heat exchanger (4) ・ ・ ・ Afterglow safety device (5) ・ ・ ・ Control device (29) ・ ・ ・ Hot water shutoff valve

Front page continuation (72) Inventor, Yoshiki Takeuchi, 2-26, Fukuzumi-cho, Nakagawa-ku, Nagoya-shi Rinnai Co., Ltd.

Claims (2)

[Claims] 1. A heat exchanger provided in a water flow circuit and heated by a gas burner, and for supplying gas to the gas burner when the temperature of accumulated water in the heat exchanger is detected and becomes abnormally high. Afterglow safety device that forcibly closes the gas valve and hot water cutoff that is provided in the water flow circuit downstream of the heat exchanger and that closes when the water flow in the water flow circuit reaches an abnormally high temperature A water heater equipped with a valve that employs a manual reset type afterglow safety device that does not return to its initial state unless it is manually operated. 2. An afterglow alarm provided by an output of an afterglow safety device for forcibly closing a gas valve is provided.
Water heater.