JP2829715B2 - Gas burner equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a boiler,
The present invention relates to a three-position control type gas burner device used for a water heater and the like, which stops the amount of combustion in a gas burner and controls the combustion amount to three positions of low combustion and high combustion.

[0002]

2. Description of the Related Art When controlling the amount of combustion in a gas burner in three positions of stop, low combustion, and high combustion, CO harmful to the human body is required.
In order to suppress the generation of (carbon monoxide) and the like, it is necessary to control the air-fuel ratio at the time of low combustion and high combustion (that is, the ratio of air and fuel supplied to the burner) to a predetermined value.

[0003] The "low" and "high" when referring to the low combustion and the high combustion, and also the low opening and the high opening described later, are relatively low in one side and relatively low in the other. Means high.

FIGS. 5 to 7 show a conventional example of a gas burner device for performing the above-described three-position control and air-fuel ratio control.

In the gas burner apparatus shown in FIG. 5, a fuel valve 12 for controlling the flow rate of fuel flowing through the fuel (ie, gas) supply line to the gas burner 2 is provided. An air valve 18 is provided for controlling the air flow therethrough, and both valves 12 and 18
Are linked by a link mechanism 22, and by using one motor 20 through this link mechanism 22, the opening degrees of both valves 12 and 18 are changed in two stages while maintaining a fixed relation to each other, thereby achieving low combustion and high combustion. It is configured to switch between combustion and combustion and to maintain the air-fuel ratio at that time at a predetermined value. The stop of the combustion is performed by closing the fuel cutoff valves 6 and 8 and stopping the blower 14.

The fuel supply line is provided with two fuel shutoff valves 6 and 8 for shutting off the fuel 4 and a normally open gate valve 10. Thus, the fuel cutoff valves 6, 8
Is doubled and the gate valve 10 is provided to comply with safety standards (the same applies to other conventional examples and embodiments of the present invention). Air 16 is supplied from a blower 14.

In the gas burner apparatus shown in FIG. 6, an air supply line is provided with an air valve 18 whose opening is controlled by a motor 20, and a fuel supply line is provided with a fuel cutoff valve 8a which takes three positions of closed, half open and full open. When switching between low combustion and high combustion, first, the opening degree of the air valve 18 is controlled by the motor 20, and a signal S is given from the motor 20 side to the fuel cutoff valve 8a side, so that a predetermined opening of the air valve 18 is performed. The opening degree of the fuel cutoff valve 8a is switched on the basis of the degree, thereby maintaining the air-fuel ratio at the time of low combustion and at the time of high combustion at a predetermined value.

In the gas burner apparatus shown in FIG. 7, an air supply line is provided with an air valve 18 whose opening is controlled by a motor 20, and a fuel supply line is provided with a low flow rate fuel cutoff valve 8b and a high flow rate fuel cutoff valve. The valve 8c is provided in parallel with each other, and when switching between low combustion and high combustion, first, the opening degree of the air valve 18 is controlled by the motor 20 and a signal S is supplied from the motor 20 to the fuel cutoff valves 8b and 8c. Then, at a predetermined opening of the air valve 18, which of the two fuel cutoff valves 8 b and 8 c is to be opened is selectively switched. It is configured to keep the fuel ratio at a predetermined value.

[0009]

The gas burner apparatus shown in FIG. 5 has the following problems.

The opening degree of the fuel valve 12 and the air valve 18 is determined by the radius of the lever constituting the link mechanism 22. Both valves 12 and 18 are connected to one link mechanism 22, and one of the valves is adjusted. When the link mechanism 22 is moved to change the opening degree of the other valve, it is difficult to adjust the opening degree of both valves 12 and 18 to adjust the air-fuel ratio.

[0011] Both the fuel valve 12 and the air valve 18 are
The fuel valve 12, the air valve 18, and the piping for them must be placed in a large restriction because they must be arranged close to each other so that they can be connected to the link mechanism 22.

The gas burner device shown in FIG. 6 has the following problems.

The need for a special fuel shutoff valve 8a that takes three positions increases the cost.

Although the opening degree of the fuel cutoff valve 8a at the time of half-opening can be adjusted temporarily, it cannot be adjusted continuously and smoothly like the air valve 18, so that the opening degree adjustment, that is, the air-fuel ratio adjustment can be performed. difficult.

It is difficult to easily interlock the opening degree of the air valve 18 and the state of the fuel cutoff valve 8a. This is because the normal fuel cutoff valve 8a does not have an interlock switch, and cannot return a signal indicating the state of the fuel cutoff valve 8a from the fuel cutoff valve 8a side to the motor 20 side. If the interlock is not established, if the state of the fuel cut-off valve 8a is not in accordance with the command, it cannot be detected, so that the air-fuel ratio control is erroneously performed. There is no particular case where an interlock switch cannot be attached to the fuel cutoff valve 8a, but this increases the cost.

Since the operating speed of the air valve 18 is different from that of the fuel cutoff valve 8a, when switching from low combustion to high combustion or vice versa, the air-fuel ratio temporarily becomes abnormal during the switching, causing CO generation and the like. Cause. This will be described in detail with reference to FIGS.

As shown in FIG. 8, when a high combustion command is received, first, the opening of the air valve 18 starts to increase, and when it reaches a predetermined opening P, the fuel cutoff valve 8a from the motor 20 side. The switching signal is output to the side, and the fuel cutoff valve 8a is fully opened. When the low combustion command is received, first, the opening of the air valve 18 starts to decrease, and when it reaches a predetermined opening P, the motor 2
A switching signal is issued from the 0 side to the fuel cutoff valve 8a side, and the fuel cutoff valve 8a is opened halfway. Therefore, during the switching of the combustion amount, there always exists an air-rich region A where the air is excessive and a gas-rich region G where the fuel (gas) is excessive.

FIG. 9 shows the change in the air-fuel ratio at the time of the above switching. CO generation limit lines L1 and L2, blower 14 performance limit line L3, and air valve 18 throttle limit line L
The area surrounded by 4 is the air-fuel ratio allowable area B. When the air-fuel ratio becomes larger than the CO generation limit line L1, a large amount of CO is generated and blowout occurs in the gas burner 2. When the air-fuel ratio becomes smaller than the CO generation limit line L2,
A large amount of CO is generated, and oscillating combustion occurs in the gas burner 2. In consideration of these factors, the air-fuel ratio is usually set to, for example, around 1.2 at the time of low combustion and at the time of high combustion.

However, in the apparatus shown in FIG. 6, as shown in FIG. 8, the air becomes rich until the fuel cut-off valve 8a starts to open, and the air-fuel ratio deviates from the allowable range B to a larger value. After the opening is completed, the gas becomes rich and the air-fuel ratio deviates from the allowable range B to a smaller value, and in each case, a large amount of CO is generated.

The gas burner apparatus shown in FIG. 7 also has the following problems similarly to the apparatus shown in FIG.

Since the fuel cutoff valve 8b for low flow rate and the fuel cutoff valve 8c for high flow rate are required, the cost is increased.

It is necessary to adjust the fuel flow rate by changing the size of the fuel cutoff valves 8b and 8c or providing appropriate orifices in accordance with the amount of combustion.
It is difficult to adjust the fuel flow, that is, the air-fuel ratio.

The normal fuel cutoff valves 8b and 8c are not provided with an interlock switch, so that signals indicating their states cannot be returned from the fuel cutoff valves 8b and 8c to the motor 20 side. It is difficult to easily interlock the opening degree of the valve 18 and the operating state of the fuel cutoff valves 8b and 8c.

Air valve 18 and fuel cutoff valves 8b and 8c
Since the operating speed is different between and, when switching from low combustion to high combustion or vice versa, the air-fuel ratio temporarily becomes abnormal during the switching, causing CO generation and the like.

Therefore, the present invention is inexpensive, easy to adjust the air-fuel ratio, is not subject to restrictions on the arrangement of valves and pipes, and is safe by interlocking the fuel valve and the air valve. A main object of the present invention is to provide a gas burner device improved so that an air-fuel ratio abnormality does not occur during switching of the combustion amount.

[0026]

In order to achieve the above object, a gas burner apparatus according to the present invention comprises a fuel valve for controlling a flow rate of fuel flowing through a fuel supply line to a gas burner and a fuel shutoff for shutting off fuel flowing therethrough. A valve is provided, an air supply line to the gas burner is provided with an air valve for controlling an air flow therethrough, and the fuel valve and the air valve are provided with:
A fuel valve motor and an air valve motor for controlling them to a low opening and a high opening, respectively, and a plurality of switches for detecting a low opening state, a high opening state, and other opening states of each valve, respectively. A circuit for controlling the fuel valve motor, the air valve motor, and the fuel cutoff valve by using a signal from the switch.When switching from low combustion to high combustion, the air valve precedes the fuel valve. When switching from high combustion to low combustion, the valve control function that operates the fuel valve in the closing direction ahead of the air valve, and the correlation between the opening of the fuel valve and the air valve is constant. A control circuit having an interlock function for closing the fuel cutoff valve when the state of the relationship has continued for a predetermined time or more.

[0027]

FIG. 1 is a schematic view showing an example of a gas burner device according to the present invention. Parts that are the same as or correspond to those of the conventional example in FIGS. 5 to 7 are denoted by the same reference numerals, and differences from the conventional example will be mainly described below.

In this embodiment, a fuel valve 12 for controlling the flow rate of fuel flowing therethrough and fuel cutoff valves 6 and 8 for shutting off the fuel 4 flowing therethrough are provided in a supply line of the fuel 4 to the gas burner 2. . The reason why the fuel cutoff valve is doubled is to comply with safety standards as described above, and is not essential to the present invention. Gate valve 10
Is provided for the same reason, and is not essential to the present invention.

The fuel valve 12 has a fuel valve motor for controlling it to a low opening and a high opening, and a plurality of valves for detecting the low opening state, the high opening state, and other states of the valve 12, respectively. A fuel valve motor device 30 having a switch is connected.

The supply line of the air 16 to the gas burner 2 is provided with an air valve 18 for controlling the flow rate of the air flowing therethrough.

The air valve 18 has an air valve motor for controlling the valve 18 to have a low opening and a high opening, and a plurality of valves for detecting the low opening state, the high opening state, and other states of the valve 18, respectively. An air valve motor device 40 having a switch is connected.

Further, it is connected to a fuel valve motor device 30, an air valve motor device 40, and fuel cutoff valves 6 and 8,
A control circuit 50 for controlling them is provided.

The control circuit 50 controls the air valve 1 when the combustion amount in the gas burner 2 is switched from low combustion to high combustion.
A valve control function of operating the fuel valve 12 in the opening direction prior to the fuel valve 12 and operating the fuel valve 12 in the closing direction prior to the air valve 18 when switching from high combustion to low combustion;
2 and the opening degree of the air valve 18 deviate from the predetermined relation for a predetermined time or more, the fuel cutoff valve 6
And an interlock function for closing 8.

The fixed relationship between the opening of the fuel valve 12 and the opening of the air valve 18 is, for example, substantially the same opening. The reason why the fuel shutoff valves 6 and 8 are closed when they last for a certain time or more is
Temporary (e.g., within a few seconds) inconsistencies in the opening during switching are often possible, and are not very problematic and are tolerated.

The control circuit 50 has a stop,
A command signal for commanding low combustion and high combustion is provided.

A specific example of the fuel valve motor device 30, the air valve motor device 40 and the control circuit 50 will be described later in detail with reference to FIG.

FIG. 2 shows an example of a change in the opening of the air valve 18 and the fuel valve 12 in the gas burner device. When a high combustion command is received, first, the opening of the air valve 18 starts to increase,
Then, with a delay of a predetermined delay time t1, the opening of the fuel valve 12 starts to increase. When the low combustion command is received, first, the opening of the fuel valve 12 starts to decrease, and then a predetermined delay time t
With a delay of two, the opening of the air valve 18 starts to decrease. The delay times t1 and t2 may be determined so that the air-fuel ratio does not go out of the allowable range B in FIG. Usually, t1
= T2, but t1 ≠ t2 if necessary. Therefore, during the switching of the combustion amount, there are regions A1 and A2 that are somewhat air-rich.

The change in the air-fuel ratio at the time of the above switching is as shown in FIG. FIG. 9 shows the allowable range B of the air-fuel ratio.
Is the same as In this embodiment, when switching from low combustion to high combustion or when switching from high combustion to low combustion, the air dominance control with a little more air is performed as described above, so that the air-fuel ratio is always within the allowable range B. Can fit.

The advantage of this air superiority control will be described. As described above, the air-fuel ratio is usually set to around 1.2 at both low combustion and high combustion, and as can be seen from FIG. Is larger on the side that is larger than the side that is smaller. That is, as soon as the air flow is insufficient, CO2
Although it exceeds the generation limit line L2, even if the air flow rate increases somewhat, it does not immediately exceed the CO generation limit line L1. From this, it is understood that the air-fuel ratio can always be easily kept within the allowable range B by performing the air superiority control.

As described above, in this embodiment, the air superiority control is performed, so that the air-fuel ratio abnormality does not occur during the switching of the combustion amount, and it is safe. That is, a large amount of CO is not generated from the gas burner 2, the combustion is stable in the gas burner 2, and no oscillating combustion or blowout occurs.

Further, an interlock is provided between the fuel valve motor device 30 and the air valve motor device 40,
Since the mutual relationship between the opening degrees of the fuel valve 12 and the air valve 18 is monitored, the failure of either the fuel valve 12 or the air valve 18 can be detected and the fuel cutoff valves 6 and 8 can be closed. It is safe.

Further, since the fuel shutoff valve is expensive, the combination of the fuel valve 12 and the fuel valve motor device 30 as in this embodiment is a three-position type fuel shutoff as in the conventional example of FIG. The cost is lower than when using the valve 8a or using two fuel cutoff valves 8b and 8c as in the conventional example of FIG.

Further, the fuel valve 12 and the air valve 18 are controlled by the fuel valve motor device 30 and the air valve motor device 40.
The opening of each can be easily adjusted,
As shown in FIG. 5, the link mechanism 22 is used.
The adjustment of the air-fuel ratio is easier than in the case of using a three-position type fuel cutoff valve 8a as in the conventional example of FIG. 1 or using two fuel cutoff valves 8b and 8c as in the conventional example of FIG. be able to.

Further, since the fuel valve 12 and the air valve 18 are controlled by the fuel valve motor device 30 and the air valve motor device 40, respectively, unlike the conventional example shown in FIG.
2. There are no restrictions on the arrangement of the air valves 18 and the piping for them.

FIG. 4 is a circuit diagram showing a specific example of the fuel valve motor device 30, the air valve motor device 40, and the control circuit 50 in the device of FIG.

The fuel valve motor device 30 is, for example,
This is similar to the control motor device disclosed in JP-A-45557, which is connected to the fuel valve 12 and controls the opening thereof, and is connected to the shaft of the fuel valve motor 31. A plurality of cam switches 32 to 35 for detecting the opening of the fuel valve 12;
6 is provided. 36a and 36b are contacts of the relay 36.

The positions at which the cam switches 32 to 35 are switched can be arbitrarily adjusted. In this embodiment, the positions are set as follows. That is, the cam switch 33 switches to the a side at a predetermined high opening (for example, 100% opening). The cam switch 34 switches to the side a at a predetermined low opening (for example, 30% opening). The cam switch 32 switches to the b-side when the opening is slightly smaller than the high opening (for example, the opening is 95%). The time from when the fuel valve 12 starts to close until the cam switch 32 switches to the side b corresponds to the delay time t2 in FIG. The cam switch 35 switches to the a side at a predetermined opening between the low opening and the high opening.

The air valve motor device 40 is also, for example,
This is similar to the control motor device disclosed in JP-A-45557, which is connected to the air valve 18 and controls the opening thereof, and is connected to the shaft of the air valve motor 41. A plurality of cam switches 42 to 45 for detecting the opening degree of the air valve 18;
6 is provided. 46a and 46b are contacts of the relay 46.

The positions at which the cam switches 42 to 45 are switched can be arbitrarily adjusted. In this embodiment, the positions are set as follows. That is, the cam switch 43 switches to the a side at a predetermined high opening (for example, 100% opening). The cam switch 44 switches to the a side at a predetermined low opening (for example, 30% opening). The cam switch 42 switches to the side a when the opening is slightly larger than the low opening (for example, the opening is 50%). The time from when the air valve 18 starts to open until the cam switch 42 switches to the a side corresponds to the delay time t1 in FIG. The cam switch 45 switches to the a side at a predetermined opening between the low opening and the high opening. The opening at which the cam switch 45 switches to the a side and the opening at which the cam switch 35 switches to the a side are set to the same opening in this example, for example, 65%.

The terminals 52 and 54 are connected to a power source (for example, A
C200V). The contact 56 is a contact for turning the circuit on and off. The contact 58 is a contact for switching between low combustion and high combustion, and is turned off when performing low combustion and turned on when performing high combustion by a signal from the outside.

To explain an operation example, when switching from low combustion to high combustion, the contact 58 is turned on. In response, first, the relay 46 in the air valve motor device 40 is turned on, the contact 46a is turned on, current flows in the opening direction circuit of the air valve motor 41, and the air valve motor 41 starts rotating in the opening direction. , The opening of the air valve 18 starts to increase. Air valve 18
Is slightly increased, the cam switch 42 is switched to the "a" side, and accordingly, a voltage is applied to the relay 36 in the fuel valve motor device 30 to turn on the relay 36, and the contact 36
a is turned on, a current flows in the opening direction circuit of the fuel valve motor 31, and the fuel valve motor 31 starts rotating in the opening direction.
2 starts to increase. This is the above-described air superiority control.

When the opening of the air valve 18 and the fuel valve 12 reaches a predetermined high opening, the cam switches 43 and 33 are set to a
The air valve motor 41 and the fuel valve motor 31 stop there.

While the openings of the air valve 18 and the fuel valve 12 are being increased, the cam switch 45 is first switched to the a side, and the cam switch 35 is immediately switched to the a side. This is normal. However, air valve 1
If there is an abnormality in the opening of either the fuel switch 8 or the fuel valve 12, one of the cam switch 45 and the cam switch 35 will be on the a side and the other will be on the b side, and current will flow through the timer 60 to start the timer 60. The timer 60 is set to, for example, 2 seconds. When the opening abnormality continues for 2 seconds or more, the timer 60 is turned on, the contact 60a is turned on, the relay 62 is operated, and the contact 62b is turned off. No voltage is applied to the fuel cutoff valves 6 and 8, and both fuel cutoff valves 6 and 8 are shut off. This is the interlock described above.

When switching from high to low combustion, contact 58 is turned off and relays 36 and 46 are correspondingly turned off.
Is turned off, and the contacts 36b and 46b are turned on. In response, first, a current flows in the closing direction circuit of the fuel valve motor 31, the fuel valve motor 31 starts rotating in the closing direction, and the opening of the fuel valve 12 starts to decrease. When the opening of the fuel valve 12 slightly decreases, the cam switch 32 switches to the b side,
In response, a current flows in the closing direction circuit of the air valve motor 41, and the air valve motor 41 starts rotating in the closing direction.
8 begins to decrease. This is also the air superiority control described above.

When the opening of the fuel valve 12 and the air valve 18 reaches a predetermined low opening, the cam switches 34 and 44 are set to a
Side, whereby the fuel valve motor 31 and the air valve motor 41 are each stopped.

As described above, switching of the combustion amount in the gas burner 2, air superiority control at that time, and interlocking are performed.

[0057]

Since the present invention is configured as described above, it has the following effects.

In place of the expensive fuel cutoff valve, a combination of a less expensive fuel valve and a fuel valve motor is used, so that the cost is lower than that of the conventional fuel cutoff valve system.

Since the respective opening degrees of the fuel valve and the air valve can be easily adjusted by the fuel valve motor and the air valve motor, the air-fuel ratio can be easily adjusted.

Since the fuel valve and the air valve are controlled by the respective fuel valve motor and air valve motor, there is no restriction on the arrangement of the fuel valve, the air valve and the piping for them.

Since an interlock is established between the fuel valve motor side and the air valve motor side, and the interrelationship between the opening degrees of the fuel valve and the air valve is monitored, either the fuel valve or the air valve fails. However, it is safe because the fuel cutoff valve can be detected and the fuel cutoff valve can be closed.

Since the air superiority control is performed, the air-fuel ratio abnormality does not occur during the switching of the combustion amount, so that it is safe.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of a gas burner device according to the present invention.

FIG. 2 is a schematic diagram showing an example of a change in the opening degree of an air valve and a fuel valve in the apparatus of FIG.

FIG. 3 is a schematic diagram showing an example of a change in a combustion range and an air-fuel ratio in the device of FIG. 1;

FIG. 4 is a circuit diagram showing a specific example of a fuel valve motor device, an air valve motor device, and a control circuit in the device of FIG.

FIG. 5 is a schematic view showing an example of a conventional gas burner device.

FIG. 6 is a schematic view showing another example of a conventional gas burner device.

FIG. 7 is a schematic view showing still another example of the conventional gas burner device.

FIG. 8 is a schematic diagram showing an example of a change in the opening degree of an air valve and a fuel cutoff valve in the apparatus of FIG. 6;

FIG. 9 is a schematic diagram showing an example of changes in a combustion range and an air-fuel ratio in the apparatus of FIG.

[Explanation of symbols]

 Reference Signs List 2 gas burner 4 fuel 6, 8 fuel cutoff valve 12 fuel valve 16 air 18 air valve 30 fuel valve motor device 31 fuel valve motor 32 to 35 cam switch 40 air valve motor device 41 air valve motor 42 to 45 cam switch 50 control circuit

Claims (1)

(57) [Claims] In a three-position control type gas burner device for controlling the amount of combustion in a gas burner to three positions of low combustion and high combustion, a fuel valve for controlling a flow rate of fuel flowing through a fuel supply line to the gas burner. And a fuel cutoff valve for shutting off fuel flowing therethrough, and an air valve for controlling the flow rate of air flowing therethrough in an air supply line to the gas burner. The fuel valve and the air valve have low opening and high opening. The fuel valve motor and the air valve motor that respectively control the opening degree, and a plurality of switches that respectively detect a low opening state, a high opening state, and other opening states of each valve are connected, and further, A circuit that controls the fuel valve motor, air valve motor, and fuel cutoff valve using the signal from this switch. A valve control function that operates the valve in the opening direction ahead of the fuel valve, and when switching from high combustion to low combustion, operates the fuel valve in the closing direction ahead of the air valve, and the opening of the fuel valve and air valve A control circuit having an interlock function for closing a fuel cutoff valve when a state in which the mutual relationship deviates from the predetermined relationship continues for a predetermined time or more.