JPH076694B2 - Water heater safety device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a safety device for a water heater, particularly to a safety device when a heat exchanger is damaged, and any position of the heat exchanger is damaged. In such a case, the heat-sensitive means promptly and reliably detects the abnormality of the heat exchanger, and the operation of the combustion device is stopped.

[Prior Art and its Problems] A water heater has a structure in which a heat exchanger is housed in a casing, and in a water heater including a combustion device such as a gas water heater, a gas burner is provided below the heat exchanger. It is arranged.

Therefore, the heat exchanger is in a state of being heated by the gas burner when the device is used, and it is extremely long-term (long years).
In use, the heating can damage the heat exchanger. In order to ensure this safety, a safety device that stops the combustion of the gas burner when the heat exchanger is damaged has been adopted. Conventionally, this safety device has the configuration shown in FIG. 9 and FIG. Has been adopted.

Usually, in this type of device, the back side thereof faces the device installation wall surface, so damage to the back side of the heat exchanger (1) poses a serious problem. Therefore, as shown in FIG. 9, the heat-sensitive means (11) is arranged above the heat shield plate (13) arranged on the back side in the casing (10) surrounding the heat exchanger (1), 10th
As shown in the figure, the output from the heat sensitive means (11) is input to the control unit (31) of the safety device, and the solenoid valve (32) is operated by the output from the control unit (31) to operate the gas burner (2 2) is cut off or the operation of the appliance is stopped.

In this one, when the gas burner (2) is burning,
When the heat exchanger (1) is damaged, a predetermined signal output is generated from the heat sensing means (11), and this output is input to the control section (31), and the output thereof causes the solenoid valve (32) to operate and the gas burner ( The combustion of 2) stops. This ensures the safety of the device. The control device (3) including the control unit (31) is configured such that the operation of the appliance is controlled by a signal input from the operation unit, and the solenoid valve is also controlled to open and close by this control signal. To be done.

However, in this conventional device, when the heat exchanger (1) is damaged, the heat sensitive means (1
It takes a relatively long time for 1) to detect this, and the safety device may not operate promptly.

First, since the heat shield plate (13) is made of a thin metal plate, the heat shield plate (13) is partially heated by partial damage of the heat exchanger (1). This is because a certain period of time is required until the heat-sensitive means (11) becomes heat-sensitive.

Further, as the conventional heat-sensitive means (11), a thermal fuse of a type that melts at a set temperature and interrupts an electric circuit is adopted, but this thermal fuse is covered with an insulating material. Since this coating insulating material exerts a heat insulating effect, it takes a certain period of time from when the heat shield plate (13) is heated to when the temperature fuse is heated to the set temperature. is there.

The present invention is particularly intended to solve the latter problem, and "provides a heat-sensitive means (11) between the heat exchanger (1) and the inner surface of the casing (10) that accommodates the heat-exchanger (1). The safety device for a water heater, which operates the drive part of the safety device by the output from the means (11) to stop the operation of the combustion device when a part of the heat exchanger (1) is damaged. In order to improve the sensitivity of the safety device when the heat exchanger (1) is damaged, it is a specific problem that the ambient temperature of the heat-sensitive means directly acts on the heat-sensitive means.

[Technical Means] The technical means of the present invention taken to solve the above-mentioned problem is that "the heat-sensitive means (11) is used as a light transmission line (F) made of a synthetic resin to directly expose it to a detected part, The light transmission line (F) has a composition that greatly reduces the light transmission at the set temperature or blocks light transmission, and the light transmission line (F) is inserted into the optical signal circuit (4) to operate the water heater. In accordance with the change in the output of the optical signal circuit (4), the drive unit of the safety device is operated to stop the operation of the combustion device. "

[Operation] The above technical means of the present invention operates as follows.

During operation of the water heater, when the heat exchanger (1) is normal, the ambient temperature of the light transmission line (F) does not rise to the set temperature, so the output of the optical signal circuit (4) is in a steady state,
The drive of the safety device does not work. That is, the combustion device continues combustion.

A water heater has been used for a long time, and should it be a heat exchanger (1)
When the torso part is thermally deteriorated and partially damaged,
Hot air leaks from the damaged portion and the temperature in the vicinity of the light transmission line (F) rises to reach the set temperature. Since the light transmission line (F) has a composition that greatly reduces or blocks light transmission at the set temperature, the light transmission line (F) greatly reduces or blocks light transmission at this point. Has been
The output of the optical signal circuit (4) changes, whereby the drive part of the safety device operates and the operation of the combustion device is stopped.
That is, the combustion is stopped.

Here, the light transmission line (F) is placed in the atmosphere of the detected portion, and the change in the ambient temperature directly affects the light transmission line (F). Further, since the light transmission line (F) is not energized, this is a heat exchanger or casing (1
0) Furthermore, there is no risk of leakage even when in direct contact with the heat shield plate (13).

[Effects] The present invention having the above-described configuration has the following unique effects.

When the heat exchanger (1) is damaged, the safety device is operated by directly detecting the temperature change of the installation part of the heat-sensitive means (11), so that the sensitivity of the safety device becomes more sensitive than the conventional one. Safety is improved.

Since the light transmission line (F) serving as the heat-sensitive means (11) is made of synthetic resin, even if it comes in contact with each component part made of metal of the instrument, no accident such as electric leakage occurs.

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 1 to 8.

* First Embodiment A water heater according to a first embodiment shown in FIGS. 1 to 3 is a gas combustion water heater of a push-combustion type, and is a type of water heater installed on an indoor wall surface. As shown in FIG. 1, a burner chamber (14) accommodating a gas burner (2) is arranged below the heat exchanger (1), and the burner chamber (14) has the same structure as that of the conventional example. The air supply fan (15) is attached to the bottom and the valve device (V) is connected in series, these are housed in the casing (10), and a gas circuit and a water supply circuit are introduced from the lower side of the casing (10) for heat treatment. An exhaust top (12) is capped above the exchanger (1).

As shown in Fig. 1, the heat shield plate (13) has a casing (1
The inner surface of (0) is installed so as to face substantially the entire back surface of the heat exchanger (1).

In this embodiment, a light transmission line (F) as the heat-sensitive means (11) is provided on the back surface of the heat shield plate (13), that is, on almost the entire surface of the surface facing the inner surface of the casing (10) as shown in FIG. They are arranged in a meandering manner, and both ends thereof are connected to one of the first connectors (41) for optical signal connection. This first connector (41) is, as shown in FIG. 3, the other second connector (44) connected to the light source section (42) and the light projecting section (43) provided in the circuit of the optical signal circuit (4). ) And these first
The optical signal circuit (4) in which the light source section (42), the light transmission line (F) and the light projecting section (43) are connected in series is configured by connecting the connector (41) and the second connector (44).

The light projecting section (43) faces the phototransistor (40), and the phototransistor (40) is inserted into the circuit of the relay (R), and the output contact (R ₁ ) of the phototransistor (40) is connected to the gas burner (2). Is inserted in series with the electric circuit of the solenoid valve (32) inserted in the circuit.

The light transmission line (F) has a composition in which the optical signal circuit is cut off by melting at a set temperature. When the light transmission line (F) is melted at the set temperature, the phototransistor (40) becomes non-conductive. The circuit of the solenoid valve (32) is cut off to stop the combustion of the gas burner (2). Therefore, in this embodiment, the light transmission line (F) functions as the heat-sensitive means (11) of the safety device, the combination of the phototransistor (40) and the relay (R) functions as the control unit (31), and The valve (32) will function as a drive unit.

Since the light transmission line (F) is attached to the heat shield plate (13), when a part of the heat exchanger (1) is damaged at a position facing the heat shield plate, The heat shield plate (13) is heated by the hot air from the damaged portion, and the conductive heat of the heat shield plate melts the light transmission line (F) to block the optical signal.

In particular, in this embodiment, the light transmission line (F) is attached and fixed to the heat shield plate (13) in a meandering manner over substantially the entire area, so that the heat exchanger (1) is not damaged. Even if the heat shield (13) partially rises to the set temperature by the hot air of
The light transmission line (F) will be melted and cut at a portion in contact with this portion. Therefore, the detection sensitivity is further improved. Also, hooks (16) (1) cut and raised from the heat shield (13)
Since the light transmission line (F) is locked by 6), this locking work is easy.

* Second Embodiment In this embodiment, as shown in FIGS. 4 and 5, the leaf spring locking metal fittings (5) (5) are projected from the water supply pipe (T) of the heat exchanger (1). ) Is used to hold the light transmission line (F), whereby the light transmission line (F) is arranged near the body of the heat exchanger (1). And the fifth
As shown in the figure, the arrangement position of the light transmission line (F) is set to an intermediate position between the water pipes (T) and (T).

In this case, when the body of the heat exchanger (1) is damaged, the hot air from the damaged part directly acts on the light transmission line (F), which further increases the detection sensitivity. When the light transmission line (F) is wound and locked in substantially the entire body of the heat exchanger (1), the detection range is expanded and damage occurs at any place of the heat exchanger (1). However, this can be detected.

* Third Embodiment In the third embodiment shown in FIGS. 6 to 8, the heat shield plate (13) is formed in a box, and the box is placed between the box and the surface of the heat exchanger (1). An empty room (6) is formed, and this empty room (6) is communicated with the air supply path in the casing (10) only at the opening (61),
A light transmission line (F) is arranged in the vicinity of this opening, and in this case also, the same function as in each of the above-described embodiments is performed.

In this embodiment, since the water heater is of a type in which the air for combustion is supplied by the air supply fan (15), the air in the casing (10) is sucked by the air supply fan (15) and the combustion chamber Since the air is supplied to the air supply fan (15), the opening (61) faces the air supply path of the air supply fan (15).
When a part of the heat exchanger (1) is damaged, the hot air discharged into the vacant chamber (6) is guided to the opening (61) by the suction action of the air supply fan (15) and arranged in the vicinity of this. The light transmission line (F) is melted and cut, and the same operation as in each of the above-described embodiments is performed.

When the box body is of a type that surrounds the entire heat exchanger, safety is further improved.

As a safety device for realizing safe operation, a thermocouple type, a system that uses a frame rod, and the output of the heat-sensitive means shuts off the power supply circuit to the water heater, which causes the solenoid valve (32). A method of closing the valve can also be adopted.
Further, the light transmission line (F) in the above-mentioned embodiment has a composition that melts at the set temperature, but the composition is such that the light transmission level is greatly lowered or the light transmission is blocked by the alteration or melting under the set temperature condition. May be

Further, in the above-mentioned embodiment, the light transmission line (F) is not coated at all, but it is possible to coat the light transmission line (F) simply as long as it does not hinder the heat transfer from the atmosphere.

[Brief description of drawings]

FIG. 1 is an explanatory view of a first embodiment of the present invention, FIG. 2 is a perspective view of the main part thereof, FIG. 3 is a circuit explanatory view of a safety device, and FIG.
FIG. 5 is an explanatory view of the second embodiment, FIGS. 6 to 8 are explanatory views of the third embodiment, and FIGS. 9 and 10 are explanatory views of a conventional example. In the figure, (1) ...... Heat exchanger (11) ...... Heat-sensitive means (10) ...... Casing (F) ...... Light transmission line (4) ...... Optical signal circuit

Claims (1)

[Claims] 1. A heat-sensitive means (11) is provided between a heat exchanger (1) and an inner surface of a casing (10) accommodating the heat-exchanger (1), and an output from the heat-sensitive means (11) serves to drive a safety device. In a safety device for a water heater, which is operated so as to stop the operation of a combustion device when a part of the heat exchanger (1) is damaged, the heat-sensitive means (11) is made of a synthetic resin light transmitting material. Line (F), the light transmission line (F) having a composition in which the light transmittance is greatly reduced or the light transmission is blocked at a set temperature, and the light transmission line (F) is inserted into the optical signal circuit (4). However, a safety device for a water heater, in which the drive unit of the safety device is activated by the change in the output of the optical signal circuit (4) during operation of the water heater to stop the operation of the combustion device.