JPH0127338B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a so-called open-type combustion appliance such as an instantaneous water heater that releases combustion exhaust indoors, and more specifically, when a burner burns, the combustion heat is gradually stored, and A device for preventing long-term continuous use, which is provided with a heat storage member that gradually radiates heat when the burner is extinguished, and a cutoff mechanism that cuts off fuel supply to the burner when the temperature of the heat storage member rises to a first set value. Regarding open type combustion appliances.

In the open type combustion appliance with the device for preventing long-term continuous use configured as described above, when the temperature of the heat storage member rises to the first set value due to continuous use for a long time, the shut-off mechanism is activated and combustion is automatically stopped. Therefore, continuous use for an unreasonable long period of time can be prevented, and incomplete combustion due to a decrease in indoor oxygen concentration can be prevented.In addition, in a usage pattern where short use is repeated intermittently,
During intermittent use, when the indoor oxygen concentration is restored by natural ventilation when not in use, the temperature of the heat storage member decreases due to heat radiation when not in use, and after reuse the temperature of the heat storage member rises to the first set value. The period can be extended by the amount that the indoor oxygen concentration recovers due to natural ventilation when the room is not in use. It has the advantage that it can be used conveniently without any inconvenience.

However, for example, when the heat storage member is heated by the combustion gas in the combustion chamber, or the heat storage member is heated by the combustion chamber wall, as in the conventional case, the combustion gas and the combustion chamber wall are heated. The temperature is determined by the outside temperature (device ambient temperature) and the load conditions (in the case of a water heater, the water supply temperature and water supply amount to the heat exchanger).
Regardless of the disturbance factors, if you want to ensure that the desired safety effect is achieved, it is recommended to automatically stop combustion (cut off the fuel supply) as early as possible. It had to be designed and manufactured, and although it adopted an automatic combustion stop method using a heat storage member, it had the disadvantage that it was inconvenient to use.

The present invention has an object to overcome such conventional drawbacks.

The characteristic structure of the open type combustion appliance with a long-term continuous use prevention device according to the present invention, which was taken to achieve the above object, is that a heat conductive member is arranged so that a part thereof is inserted into the combustion flame of the burner. The end of the burner is connected to the heat storage member so that the combustion heat of the burner is transmitted to the heat storage member via the heat conduction member. It is as follows.

In other words, one end of the heat conductive member that transfers burner combustion heat to the heat storage member is directly heated by the combustion flame of the burner, where there is almost no temperature change due to disturbance factors such as outside temperature, and the heat is transferred to the heat storage member. Since the burner combustion heat is stored, the relationship between the usage time and the temperature of the heat storage member can be determined regardless of disturbance factors such as outside temperature.
It can be kept almost constant. Furthermore, since the heat storage member is not directly heated by the combustion flame of the burner, but is heated via the heat conduction member, it is possible to prevent malfunctions and damage to the heat storage member and the shutoff mechanism due to overheating.

Therefore, the present invention can guarantee safety for long-term continuous use as expected, and also improves the usage example compared to conventional devices since it is not necessary to perform combustion prevention early. Furthermore, it has been possible to achieve effects such as superior durability.

Embodiments of the present invention will be described below based on the drawings.

As shown in Fig. 1, a thermocouple 2 (an example of a thermoelectric member) heated by the combustion flame a of a pilot burner 1; ), pilot burner 1 and main burner 3 for heating heat exchanger A.
A combustion safety circuit 6 is provided, which includes an electromagnetic safety valve 5 which is interposed in the fuel gas supply path 4 to the thermocouple 2 and is held in an open state by an electromotive force greater than a certain level of the thermocouple 2. Therefore, in an open-type instantaneous water heater that is configured to automatically stop combustion by extinguishing the pilot burner 1, a long-term continuous use prevention device configured as follows is provided.

As shown in Fig. 3 A and B, the long-term continuous use prevention device is installed during combustion in the main burner 3 (B in the figure).
A heat storage member 7 made of metal (such as brass) that gradually stores the combustion heat (indicated by C in the figure) and gradually radiates the heat when the main burner 3 is extinguished (indicated by C in the figure); and a cutoff mechanism 8 that cuts off the supply of fuel gas to both burners 1 and 3 when the temperature rises to a first set value (t ₀ ),
In addition, the heat capacity of the heat storage member 7 and the first set value (t ₀ ) are determined after the start of use in continuous use from a state where the temperature of the heat storage member 7 is at a predetermined initial temperature.
The temperature of the heat storage member 7 is set so that the temperature of the heat storage member 7 reaches the first set value (t ₀ ) when the time T required for the indoor oxygen concentration to decrease to a certain allowable lower limit value due to its use (combustion) has elapsed. be. In other words, the fuel supply is cut off and combustion is automatically stopped before the indoor oxygen concentration drops to a value that induces incomplete combustion due to continuous use over a long period of time.

Incidentally, the cutoff mechanism 8 is configured such that after the fuel supply cutoff operation, the first
The fuel supply is cut off until the temperature of the heat storage member 7, which has reached the set value (t ₀ ), falls to the second set value (t′ ₀ ) (not shown), which is lower than the first set value (t ₀ ). It is assumed that the state is maintained, and by this,
Immediately after combustion (fuel supply) is automatically stopped, reuse is prevented when the oxygen concentration in the room has not recovered.

In the above configuration, in the case of intermittent use in which short periods of use of 1 to 2 minutes, or several minutes at most, are repeated intermittently, and in the case of intermittent use where the indoor oxygen concentration is restored by natural ventilation during non-use, the The temperature of the heat storage member 7 decreases due to heat dissipation at , and the time until the temperature of the heat storage member 7 rises to the first set value (t ₀ ) after reuse is gradually extended by the recovery of the indoor oxygen concentration when not in use. Therefore, an inappropriate automatic combustion stop, that is, an automatic combustion stop when the indoor oxygen concentration is sufficiently high is prevented. That is, such intermittent use can be carried out without any inconvenience.

As shown in FIG. 1 and FIG. 2 A and B, the cutoff mechanism shuts off the thermocouple 2 by
A switch 9 closes the safety valve 5 by grounding the positive side of the switch 9, and a switch 9 that closes the safety valve 5 by grounding the positive side of the switch ₉ . The movable contact 9A at 9 is extended so as to come into contact with the fixed contact 9C against the biasing force of the spring 9B, and thereafter, until the temperature of the heat storage member 7 falls to the second set value (t' ₀ ). By providing a coiled shape memory alloy 10 that maintains a stretched state, and closing the safety valve 5 of the combustion safety circuit 6, both burners 1 and 3
It is configured to cut off the fuel gas supply to.

Then, the heat storage member 7 is connected to the other end of the heat conduction member 11, which is arranged so that one end thereof is inserted into the combustion flame b (hereinafter referred to as the main combustion flame) of the main burner 3, Also, heat conductive member 11
one end of the main combustion flame b in the main combustion flame b
By heating the main burner 3 directly, the combustion heat of the main burner 3 is stored in the heat storage member 7 via the heat conduction member 11. A portion 11A of the heat conductive member 11 inserted into the main combustion flame b is made of a corrosion-resistant material such as stainless steel, and the other portion 11B is made of a corrosion-resistant material such as stainless steel.
is made of copper, stainless steel, etc.
It is covered with a heat insulating cover 12 for preventing heat radiation.

In other words, the above configuration effectively prevents the relationship between the usage time and the temperature of the heat storage member 7 from changing due to disturbance factors such as the outside air temperature (device ambient temperature), the water supply temperature to the heat exchanger A, and the water supply amount. As a result, the usage time due to heat storage in the heat storage member 7 can be accurately measured.

The present invention may be implemented as listed below.

As shown in FIG.
0, an elastic member 13 filled with wax that expands when heated is provided.

As shown in FIGS. 5A and 5B, the shutoff mechanism 8 includes a needle valve body 15 that opens and closes the fuel gas supply path 14 to the pilot burner 1, a spring 16 that biases this in the opening direction, and and a coiled shape memory alloy 17 that expands when the temperature of the heat storage member 7 rises to a first set value (t ₀ ) and closes the needle valve body 15 against the urging force of the spring 16. When the temperature of the heat storage member 7 rises to the first set value (t ₀ ), the pilot burner 1 is extinguished and the safety valve 5 of the combustion safety circuit 6 is closed. , 3 should be cut off.

The shutoff mechanism 8 is configured to close a dedicated fuel valve separate from the safety valve 5 of the combustion safety circuit 6.

[Brief explanation of drawings]

Figures 1 to 3 show examples, Figure 1 is a schematic configuration diagram, Figure 2 A and B are side views of the main parts in each operating state, and Figure 3 A and B are used and unused. This is a time chart showing the temperature change of the heat storage member due to the change in temperature of the heat storage member. FIGS. 4A and 4B and FIGS. 5A and 5B are side views of the main parts in each operating state, respectively, showing another embodiment. 3...Burner, 7...Heat storage member, 8...Shutoff mechanism, 11...Heat conduction member, 4...Fuel supply path, 1
... Pilot burner, 2 ... Thermoelectric member, 5 ...
…safety valve.

Claims (1)

[Scope of Claims] 1. A heat storage member 7 that gradually stores the combustion heat during combustion of the burner 3 and gradually radiates heat when the burner 3 is extinguished, and the temperature of the heat storage member 7 is set to a first set value (t ₀ In an open type combustion appliance equipped with a device for preventing long-term continuous use, which is equipped with a cutoff mechanism 8 that cuts off the fuel supply to the burner 3 when the temperature rises to The other end of the heat conduction member 11 arranged in the above position is connected to the heat storage member 7, so that the combustion heat of the burner 3 is transmitted to the heat storage member 7 via the heat conduction member 11. An open combustion appliance with a device to prevent continuous use for long periods of time. 2 After the cutoff mechanism 8 operates, the fuel supply cutoff state is maintained until the temperature of the heat storage member 7 falls to a second set value (t' ₀ ) lower than the first set value (t ₀ ). An open-type combustion appliance with a long-term continuous use prevention device according to claim 1, which retains the following: 3 The above-mentioned shutoff mechanism 8 is interposed in the fuel supply path 4 to the burner 3, and is held open with an electromotive force of a certain level or more of the thermoelectromotive member 2 heated by the combustion flame of the pilot burner 1. The open type combustion appliance with a long-term continuous use prevention device according to claim 1 or 2, wherein the fuel supply is cut off by closing the safety valve 5. 4. Open type combustion with a device for preventing long-term continuous use according to any one of claims 1 to 3, wherein the portion of the heat conductive member 11 inserted into the combustion flame is made of a corrosion-resistant material. utensils.