JP5589681B2 - Combustion device - Google Patents

Description

  The present invention relates to a combustion apparatus that can be suitably used as, for example, a component of a gas hot water supply apparatus, and more particularly to a combustion apparatus configured to be able to cope with a change in the type of fuel.

  In a combustion apparatus that supplies combustion air to a burner using a fan, it is desirable to make the air-fuel ratio constant and to improve the combustibility. Therefore, conventionally, there is means for controlling the fuel supply pressure to the burner using a pressure regulating valve of a type called a pressure equalizing valve (see, for example, Patent Documents 1 and 2). The pressure regulating valve uses the discharge pressure of the fan as a signal pressure and controls the fuel supply pressure to the burner to a pressure corresponding to the signal pressure. According to such a configuration, for example, when the supply amount of combustion air from the fan to the burner is large and the discharge pressure of the fan is high, the fuel supply amount to the burner correspondingly increases, and the air-fuel ratio is constant. Can be achieved.

  However, in the prior art, as described below, when the type of fuel is changed, a problem may occur and there is room for improvement.

  That is, in the combustion apparatus, the amount of heat generated by the fuel may change, for example, when the fuel is changed from 12A gas to 13A gas. In such a case, it is desirable to set the air-fuel ratio corresponding to the calorific value of the fuel after the change. However, conventionally, it is difficult to appropriately deal with such a situation, and the combustibility deteriorates. There was a fear. More specifically, conventionally, when the fuel type is changed, the amount of combustion air supplied to the burner is changed by changing the rotational speed of the fan in accordance with the changed fuel type. There is a means to adjust. However, even if such a means is adopted as it is in a combustion apparatus equipped with the pressure regulating valve, an appropriate air-fuel ratio suitable for the fuel after the type change cannot be obtained. When the fan speed is changed in response to the change in the fuel type, the fan discharge pressure (signal pressure) changes, and the fuel supply pressure and fuel supply amount change accordingly. The air-fuel ratio before the fuel change is only maintained, and an air-fuel ratio suitable for the fuel after the change cannot be obtained.

JP 2007-107865 A JP-A-60-26220

  The present invention has been conceived under the circumstances described above. In a combustion apparatus that controls the fuel supply pressure to a burner by using the discharge pressure of a fan that supplies combustion air as a signal pressure. An object of the present invention is to provide a combustion apparatus that can obtain an air-fuel ratio appropriately corresponding to the fuel even when the type of fuel is changed.

  In order to solve the above problems, the present invention takes the following technical means.

Combustion apparatus provided by the present invention, a fan for supplying combustion air to the burner, provided in the middle of the fuel supply route to the burner, and secondary flow from the primary side flow passage of the fuel supply passage A main pressure adjusting valve for changing the flow rate of fuel to the road, and an auxiliary pressure adjusting valve for controlling the pressure of the secondary side flow path with the discharge pressure of the fan as a signal pressure The auxiliary pressure regulating valve is connected to the primary side flow path and the secondary side flow path through first and third flow paths, respectively, and the first The pressure of the fuel flowing through the second flow path branchingly connected to the flow path is applied to the main pressure regulating valve, and the auxiliary pressure regulating valve increases as the signal pressure increases. To reduce the flow rate of fuel flowing from the road to the third flow path. As a result of the increase in the flow rate of fuel in the second flow path, the main pressure adjustment valve is configured to increase the flow volume of fuel from the primary flow path to the secondary flow path. In addition, as the third flow path, the upstream side and the downstream side of which one end side communicates with the first and second control target areas as the relative upstream side area and the downstream side area in the secondary side flow path. A third flow path on the side, and when the type of fuel supplied to the burner is determined, and when it is determined that this fuel is of a type having a larger calorific value, the first and The first control target region is selected from among the second control target regions, and fuel is supplied from the auxiliary pressure regulating valve to the first control target region via the third flow path on the upstream side. The fuel is of a type with a smaller predetermined calorific value If it is determined, select the second control region, to supply the fuel from the auxiliary pressure-regulating valve through a third flow path of the downstream side with respect to the second control region It is further characterized by further comprising control means capable of performing operation control.

According to such a configuration, the following effects can be obtained.
That is, in the above-described configuration, the fuel supply pressure and supply amount to the burner differ depending on which of the first and second control target regions is the control target region. This is because the fuel supply pressure becomes lower in the fuel supply passage as it goes downstream, and when the region close to the burner on the downstream side of the combustion supply passage is set to a predetermined pressure, the supply pressure to the burner is the predetermined pressure. However, if the area far from the burner on the upstream side of the fuel supply passage is set to a predetermined pressure, the fuel is supplied to the burner with a relatively large pressure drop. Will be done. Therefore, the air-fuel ratio differs depending on which of the first and second control target regions is to be controlled. The control means is preferable for appropriately burning the actual fuel in order to determine the fuel type and to select one of the first and second control target regions according to the fuel type. It becomes possible to set the air-fuel ratio. As a result , even if the type of fuel is changed, the air-fuel ratio can be set to match the changed fuel, and the combustibility can be improved.

Furthermore, according to the above-described configuration, the present invention is intended to suppress the increase in the overall size while the overall number of parts is increased as compared with the case where the fuel gas pressure is adjusted using only one pressure regulating valve. It is possible to appropriately obtain the effect to be performed. That is, the auxiliary pressure regulating valve plays a role as a device for controlling the main pressure regulating valve, but the auxiliary pressure regulating valve can be formed in a considerably small size. On the other hand, the main pressure regulating valve is provided in the middle of the fuel supply path and controls the fuel supplied to the burner. As for the regulating valve, it is possible to suppress the enlargement as much as possible by reducing the stroke of the movable part, which is an advantage in reducing the overall size.

  Other features and advantages of the present invention will become more apparent from the following description of embodiments of the present invention with reference to the accompanying drawings.

It is sectional drawing which shows an example of a combustion apparatus typically. It is sectional drawing which shows the auxiliary | assistant pressure control valve used for the combustion apparatus shown in FIG. It is a flowchart which shows an example of the operation processing procedure of the control part with which the combustion apparatus shown in FIG. 1 was equipped. It is sectional drawing which shows typically an example of the combustion apparatus to which this invention was applied. It is a flowchart which shows an example of the operation processing procedure of the control part with which the combustion apparatus shown in FIG. 4 was equipped.

  Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings.

A combustion apparatus C1 shown in FIG. 1 is configured as a gas hot water supply apparatus provided with a heat exchanger 19 for heating hot water, and gas jet nozzles from a gas burner 2, a fan 3 and a gas pipe 40 arranged in the can 1 A fuel supply path 4 formed in series to the head 41, an on-off valve Vc, a main pressure adjusting valve Va, an auxiliary pressure adjusting valve Vb, a control unit 8, and a switching valve 82 are provided. The main pressure regulator valve Va and the auxiliary pressure-regulating valve Vb is by this Ragakyo work, serves the function of controlling the fuel supply pressure to a predetermined pressure as described below.

  The fan 3 is a sirocco fan, for example, and sends combustion air into the can 1. First and second signal pressure detectors 31 and 32 for detecting the discharge pressure of the fan 3 as two types of signal pressures Ps1 and Ps2 are provided in or near the discharge port of the fan 3. Yes. However, details of these configurations will be described later. The gas ejection nozzle head 41 is located at the end of the fuel supply path 4 and ejects fuel gas from the nozzle 41a. The jetted fuel gas is supplied to the gas burner 2 and burned while being mixed with combustion air. From the combustion gas generated by this combustion, heat is recovered by the heat exchanger 19, and hot water flowing through the heat exchanger 19 is heated. The combustion gas after heat recovery is discharged from the exhaust port 11 as exhaust gas.

  The fuel supply path 4 has a configuration in which an on-off valve Vc and a main pressure adjustment valve Va are connected to a gas pipe 40 that supplies fuel gas. In the drawing, the main pressure regulating valve Va and the gas ejection nozzle head 41 are connected via the gas pipe 40a, but they can also be directly connected. The on-off valve Vc is for turning on / off the fuel gas supply, and is provided with a mechanism for reciprocating the valve main body 51 using a solenoid 50, as in the known art.

  The main pressure adjustment valve Va is connected to the downstream side of the on-off valve Vc. The basic configuration of the main pressure regulating valve Va is the same as that of the conventional traditional pressure regulating valve, and opens and closes the pressure regulating hole 42 at the boundary between the primary flow path 4a and the secondary flow path 4b of the fuel gas. A valve main body 60, a diaphragm D1 that supports the valve main body 60, and a return spring 62. The diaphragm D <b> 1 receives the secondary pressure P <b> 2 of the fuel gas and a later-described control pressure Pd supplied to the pressure receiving chamber 63.

  The auxiliary pressure adjusting valve Vb does not directly control the pressure in the fuel supply path 4, but controls the main pressure adjusting valve Va. In FIG. 1, for convenience of explanation, the main pressure adjustment valve Va and the auxiliary pressure adjustment valve Vb are shown not to have a large difference. However, the auxiliary pressure regulating valve Vb in this embodiment is actually considerably smaller in size than the main pressure regulating valve Va (for example, the dimensions of the width and height in the vertical and horizontal directions are 1 / th that of the main pressure regulating valve Va. A small size suppressed to a size of about 4 to 1/7).

  As clearly shown in FIG. 2, the auxiliary pressure regulating valve Vb includes a casing 70, which is divided into a pressure receiving chamber 75a and a secondary pressure chamber 75b by a diaphragm D2, and first and second springs S1, S2. A cylindrical pressure adjusting hole forming part 72 having a pressure adjusting hole 71 and a valve main body part 73 are provided. The valve main body 73 is a portion of the diaphragm D2 that faces the pressure adjusting hole 71. When the diaphragm D2 moves downward in FIG. 2 and approaches the pressure adjusting hole 71, the amount of fuel gas that passes through the pressure adjusting hole 71 Decrease.

A first flow path 74 a is connected to the pressure regulation hole forming portion 72. As shown in FIG. 1, the first flow path 74 a has an orifice 49 and supplies the primary pressure P <b> 1 of the fuel supply path 4 to the pressure regulation hole forming portion 72. A second flow path 74b is connected to the first flow path 74a, and a control pressure Pd, which is a pressure in the second flow path 74b, acts on the pressure receiving chamber 63 of the main pressure regulating valve Va. .
This control pressure Pd corresponds to the valve opening degree of the auxiliary pressure regulating valve Vb. That is, if the distance between the valve body 73 and the pressure adjusting hole 71 is large, the fuel gas in the first flow path 74a flows more into the secondary pressure chamber 75b, and the flow rate in the second flow path 74b decreases . The control pressure Pd becomes low. On the other hand, the control pressure Pd increases as the distance decreases. The secondary pressure chamber 75b communicates with the secondary channel 4b of the fuel supply channel 4 via the third channel 74c. Therefore, the pressure in the secondary pressure chamber 75b is equal to the secondary pressure P2 in the secondary channel 4b.

  One of the two types of signal pressures Ps1 and Ps2 detected by the first and second signal pressure detectors 31 and 32 is selectively supplied to the pressure receiving chamber 75a via the fourth channel 74d. Is done. This selection operation is performed under the control of the control unit 8 using the switching valve 82. The first signal pressure detection unit 31 is located upstream of the second signal pressure detection unit 32 in the air discharge direction. Based on such a difference in arrangement, the values of the signal pressures Ps1, Ps2 are different. In the present embodiment, a resistance plate 39 is provided on the downstream side of the first and second signal pressure detections 31 and 32. The resistance plate 39 is useful for increasing the signal pressures Ps1 and Ps2 and increasing the secondary pressure P2. In the upstream region of the resistance plate 39, the pressure is higher as it approaches the resistance plate 39. Therefore, in this embodiment, there is a relationship of Ps2> Ps1. However, unlike the present embodiment, when the resistance plate 39 is not provided, the relationship of Ps1> Ps2 is established, contrary to the above.

In the main pressure adjustment valve Va and the auxiliary pressure adjustment valve Vb, the secondary pressure P2 is controlled by the following operation. That is, for example, when the signal pressure Ps1 is supplied to the pressure receiving chamber 75a of the auxiliary pressure regulating valve Vb, the diaphragm D2 is pushed by the signal pressure Ps1 and moves in a direction to close the pressure adjusting hole 71. In this case, the sum of the pressing force of the signal pressure Ps1 on the diaphragm D2 and the pressing force of the first spring S1 is balanced with the sum of the pressing force of the secondary pressure P2 on the diaphragm D2 and the pressing force of the second spring S2. Diaphragm D2 moves to the position. As described above, the control pressure Pd depends on the position of the diaphragm D2. Main pressure adjustment valve V
At a, the control pressure Pd causes the diaphragm D1 to move in the direction of increasing the valve opening. In this case, the secondary pressure P2 moves to a position that balances with the signal pressure Ps1 supplied to the auxiliary pressure regulating valve Vb. Will be. In this way, the secondary pressure P2 can be controlled to a pressure (for example, the same pressure) corresponding to the signal pressure Ps1. Of course, when the signal pressure Ps2 is used instead of the signal pressure Ps1, the secondary pressure P2 becomes a pressure corresponding to the signal pressure Ps2.

  The control unit 8 is an example of the control means referred to in the present invention, and is configured using a microcomputer or the like. This control part 8 performs operation control of each part of the combustion apparatus C1, and various data processing. As one of such processes, the type of fuel gas supplied to the burner 2 is determined, and one of the signal pressures Ps1 and Ps2 is selected according to the determination result, and the selected signal pressure is determined. Control for supplying the pressure receiving chamber 75a is executed. This control is performed using the switching valve 82. The method of determining the type of fuel gas has been conventionally known (for example, JP 2003-194330 A, JP 58-214713 A, JP 56-162319 A, and Japanese Patent Publication No. 06-37971 In the present embodiment, such a known method can be used. For example, a method of comparing the output number when the burner 2 is actually driven and the target combustion number at that time and determining the type of fuel gas based on the difference is used. it can. As will be described later, the combustion apparatus C1 of the present embodiment is configured to be able to cope with any of the cases where the fuel gas is “12A” or “13A”. The fuel gases “12A” and “13A” have a relationship in which “13A” has a higher calorific value than “12A”.

  Next, the operation of the above-described combustion apparatus C1 will be described. In addition, an example of an operation processing procedure by the control unit 8 will be described with reference to the flowchart of FIG.

  First, the control unit 8 performs, for example, a setting corresponding to the fuel gas “13A” as an initial setting (S1). In the setting corresponding to the fuel gas “13A”, Ps1 on the low pressure side is selected from the signal pressures Ps1 and Ps2 and supplied to the pressure receiving chamber 75a. The rotational speed of the fan 3 is also a speed set in advance corresponding to “13A”.

  During the drive combustion of the burner 2, the control unit 8 always or almost always determines the type of fuel gas (S2). As a result, when the fuel gas is “13A”, the initial setting state described above is continued (S3: YES, S5 (S1)). Therefore, the secondary pressure P2 of the fuel supply path 4 becomes a value corresponding to the signal pressure Ps1, and is a lower value than the case of fuel gas “12A” described later. As a result, the air-fuel ratio becomes slightly large, and the combustibility of the fuel gas “13A” having a larger calorific value can be made good.

  Next, when the fuel gas is changed from “13A” to “12A” and the control unit 8 determines that, the setting content corresponding to “12A” is switched (S3: NO, S4). This switching is performed by operating the switching valve 82, whereby the signal pressure Ps2 is supplied to the pressure receiving chamber 75a instead of the signal pressure Ps1. The rotation speed control of the fan 3 is also switched to the content preset for “12A”. When such switching is performed, the secondary pressure P2 corresponds to the signal pressure Ps2, and is higher than the previous “13A”. For this reason, the air-fuel ratio becomes slightly small, and the combustibility of the fuel gas “12A” having a small calorific value can be made good. Thus, in this combustion apparatus C1, it is possible to set the air / fuel ratio suitable for the fuel gas regardless of whether the fuel gas is “13A” or “12A”.

FIG. 4 shows an embodiment of a combustion apparatus according to the present invention. In the figure, the same or similar elements as those of the above embodiment are denoted by the same reference numerals as those of the above embodiment, and the duplicate description is omitted.

  In the combustion apparatus C2 shown in FIG. 4, only one signal pressure detection unit 33 is provided, and one type of signal pressure Ps detected by the signal pressure detection unit 33 is a pressure receiving chamber 75a of the auxiliary pressure regulating valve Vb. It is comprised so that it may be supplied to. However, the secondary side flow path 4b of the fuel supply path 4 is provided with first and second control target areas A1 and A2 as pressure control target areas.

  More specifically, the first control target area A1 is an upstream area of the secondary flow path 4b, and the second control target area A2 is a downstream area. The secondary pressure chamber 75b of the auxiliary pressure regulating valve Vb is connected to the ports 68a and 68b opened in the first and second control target areas A1 and A2 via the third flow paths 74c and 74c ′. Yes. A switching valve 83 is provided in the third flow paths 74c and 74c ′, and one of the first and second control target areas A1 and A2 is selectively selected by the switching operation of the switching valve 83. It is possible to communicate with the secondary pressure chamber 75b. The operation of the switching valve 83 is controlled by the control unit 8. The control unit 8 discriminates the type of the fuel gas as in the above embodiment, and selects one of the first and second control target areas A1 and A2 according to the discriminated type of fuel. Control is performed on the selected region as a pressure control target.

  Next, the operation of the combustion device C2 will be described. In addition, an example of an operation processing procedure of the control unit 8 will be described with reference to a flowchart shown in FIG.

  First, similarly to the above-described embodiment, the control unit 8 performs a setting corresponding to, for example, the fuel gas “13A” as an initial setting (S1 ′). In the initial setting in the present embodiment, the rotation speed of the fan 3 is set to a speed corresponding to “13A”, and the first control target area among the first and second control target areas A1 and A2. A1 is selected and set in a state of communicating with the secondary pressure chamber 75b.

  During the drive combustion of the burner 2, the control unit 8 always or almost always discriminates the type of fuel gas (S2) as in the above embodiment, and when the fuel gas is "13A" The initial setting state is continued (S3: YES, S6 (S1 ′)). In this case, the secondary pressure P in the first control target region A1 is controlled to a value corresponding to the signal pressure Ps (for example, the same pressure as the signal pressure Ps). On the other hand, the first control target area A1 is located on the upstream side of the secondary side flow path 4b, but the fuel pressure decreases in the secondary side flow path 4b as it goes downstream. Therefore, the pressure P2 ″ in the gas ejection nozzle head 41 located considerably downstream of the first control target area A1 is precisely lower than the secondary pressure P2, and will be described later as a fuel gas “12A”. It becomes a lower value than the case of. As a result, the air-fuel ratio becomes slightly large and the combustibility of the fuel gas “13A” having a large calorific value is good.

Next, when the fuel gas is changed from “13A” to “12A” and the control unit 8 determines that, the setting content corresponding to “12A” is switched (S3: NO, S4 ′). This switching is performed by operating the switching valve 82 in addition to changing the content of the rotational speed control of the fan 3, thereby replacing the first control target area A 1 with the second control target area A 2. Communicates with the secondary pressure chamber 75b. Under such a setting, the secondary pressure P2 ′ in the second control target area A2 becomes a pressure corresponding to the signal pressure Ps. Since the second control target area A2 is located downstream of the first control target area A1, the amount of pressure drop from the second control target area A2 to the gas ejection nozzle head 41 is as follows. Few. Therefore, the pressure P2 ″ in the gas ejection nozzle head 41 is higher than in the case of “13A”. As a result, the air-fuel ratio becomes slightly small, and the combustibility of the fuel gas “12A” with a small calorific value is good. Thus, also in this combustion apparatus C2, the fuel gas is "13A", "12A
In any case, the air-fuel ratio suitable for the fuel gas can be set to ensure good combustion performance.

  The present invention is not limited to the contents of the above-described embodiment. The specific configuration of each part of the combustion apparatus according to the present invention can be variously changed in design.

In the present invention, it is configured so as to correspond to two types of fuel, but it can be further developed to be configured so as to be compatible with three or more types of fuel. For example, a third control target area may be provided in addition to the first and second control target areas . Even such a configuration is included in the technical scope of the present invention . The type of fuel is not limited to the fuel gases “12A” and “13A”.

  The combustion apparatus according to the present invention may be configured as a combustion apparatus such as a fan heater, a stove, or an incineration combustion apparatus, for example, instead of a hot water apparatus such as a hot water supply apparatus provided with a heat exchanger.

C1, C2 Combustors A1, A2 First and second control target areas Va main pressure regulating valve (pressure regulating valve)
Vb Auxiliary pressure regulating valve (pressure regulating valve)
Ps, Ps1, Ps2 Signal pressure P2, P2 ′ Secondary pressure 2 Burner 3 Fan 4 Fuel supply path 8 Control unit (control means)
31, 32 1st and 2nd signal pressure detection part 33 Signal pressure detection part

Claims (1)

A fan for supplying combustion air to the burner;
A main pressure regulating valve provided in the middle of the fuel supply path to the burner and for changing the flow rate of fuel from the primary flow path to the secondary flow path of the fuel supply path;
An auxiliary pressure regulating valve for setting the discharge pressure of the fan as a signal pressure and controlling the pressure of the secondary flow path;
A combustion device comprising:
The auxiliary pressure regulating valve is connected to the primary flow path and the secondary flow path via first and third flow paths, and is branched to the first flow path. The pressure of the fuel flowing through the second flow path is provided so as to act on the main pressure adjusting valve, and the auxiliary pressure adjusting valve increases from the first flow path to the third flow path as the signal pressure increases. As a result of increasing the flow rate of the fuel in the second flow path by operating to reduce the flow rate of the fuel flowing through the main pressure control valve, the main pressure regulating valve is moved from the primary flow path to the secondary flow path. It is configured to increase the flow rate of fuel,
The third flow path includes an upstream side and a downstream side in which one end side communicates with the first and second control target areas as the relative upstream area and the downstream area in the secondary flow path. A third flow path is provided,
When the type of fuel supplied to the burner is determined and it is determined that the fuel is of a type having a larger calorific value, the first and second control target regions out of the first control target region A control target region is selected, and fuel is supplied from the auxiliary pressure regulating valve to the first control target region via the third flow path on the upstream side. If it is determined that the second control target region is selected, the auxiliary pressure regulating valve is selected via the third flow path on the downstream side with respect to the second control target region. A combustion apparatus further comprising control means capable of performing operation control for supplying fuel from the fuel .

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