JPH07151326A - Combustion device - Google Patents

Abstract

PURPOSE:To accurately detect an amount of air supplied from a combustion fan to a burner. CONSTITUTION:A suction air pressure detecting port 8 is arranged in a surrounding region of an air suction port 7 of a combustion fan 2. A reference pressure detecting port 12 is installed within an equipment case 1. spaced apart from the suction air pressure detecting port 8. A pressure P1 at the suction air detected pressure port 8 and a pressure P0 at the reference pressure detecting port 12 are fed to a pressure sensor 11. An amount of displacement of a diaphragm 22 displaced in response to a differential pressure between P1 and P0 is detected by a magnetic sensor and then a differential pressure detected signal of the magnetic sensor is added to a control part 31 as an air supplying flow rate detecting signal. The control part 31 performs a control over an amount of fed air in response to an amount of combustion based on the supplied air flow rate sensing signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion apparatus equipped with combustion air supply amount detecting means.

[0002]

2. Description of the Related Art FIG. 16 shows a schematic configuration of a water heater generally known as a combustion device. In the figure, 1 is an appliance case, 2 is a combustion fan as an air supply unit, 3 is a burner, 4 is a hot water heat exchanger, and 5 is an appliance case 1.
The air intakes provided in each are shown. In this type of water heater, a water supply pipe (not shown) is connected to the hot water heat exchanger 4
The water supplied to is heated by the combustion heat of the burner 3 to produce hot water, and this hot water is guided from the outlet side of the hot water heat exchanger 4 to a desired hot water supply location through a hot water supply pipe (not shown).

The combustion operation of the water heater is controlled by a control device, and the control device receives information on the incoming water temperature, the incoming water amount, and the outgoing hot water temperature, and controls the burning amount so that the incoming water temperature becomes a set temperature. In addition, the supply amount of combustion air is controlled so as to match the combustion amount.

In order to control the supply amount of this combustion air,
In this type of water heater, a wind speed sensor 6 is provided at the outlet of the combustion fan 2, and the combustion fan 2 is
The amount of air supplied from the burner 3 to the burner 3 is detected, and the rotational speed of the combustion fan 2 is controlled based on the detected value, or a damper (not shown) provided in the air passage such as the outlet of the combustion fan 2 is used. The amount of air (combustion air amount) corresponding to the amount of combustion is controlled by controlling the opening / closing amount of (1).

[0005]

However, in the area on the outlet side of the combustion fan 2, the direction of the air flow and the flow velocity vary greatly depending on the location of the cross section of the air passage. Since the direction and flow velocity of the combustion fan 2 fluctuate with time, the amount of air supplied from the combustion fan 2 to the burner 3 cannot be accurately detected, which causes a problem that the control accuracy of the combustion air amount decreases.

In order to avoid such variations in wind speed detection by the wind speed sensor 6, the air supply amount may be detected based on the power consumption (work load) of the combustion fan 2 without using the wind speed sensor 6. Although it is possible, this method indirectly detects the air supply amount by the fan power consumption, so it is still difficult to accurately obtain the air supply amount, and the air supply amount corresponding to the combustion amount is finely adjusted. There was a problem that it could not be controlled.

The present invention has been made to solve the above conventional problems, and an object thereof is to provide a supply air amount detecting means capable of accurately detecting the supply air amount supplied from a combustion fan to a burner. An object of the present invention is to provide a combustion device provided with the device.

[0008]

In order to achieve the above object, the present invention is constructed as follows. That is, the present invention is directed to a burner provided in an instrument case, an air supply unit for supplying combustion air to the burner, and an air supply amount detection unit for detecting an air supply amount supplied from the air supply unit to the burner. In the combustion device for controlling the combustion air amount according to the combustion amount based on the air supply amount detection information of the air supply amount detection means, the air supply amount detection means is provided on the side of the intake port of the air supply means. The intake pressure detection port provided in the surrounding area, the reference pressure detection port provided at a position distant from the air supply means, and the pressures of the intake pressure detection port and the reference pressure detection port are introduced to supply the differential pressure. And a differential pressure flow rate detection means for detecting and outputting as an air flow rate detection signal.

Further, a donut-shaped intake pressure introducing unit is mounted around the intake port side of the air supply means, a continuous slit opening is provided over the entire circumference of the donut-shaped inner peripheral surface, and the slit opening is inhaled. That the pressure detecting port is used, that the pressure introducing passage extending from the intake pressure detecting port to the differential pressure flow rate detecting means is provided with an intake pressure detecting buffer part having a buffer volume for pressure fluctuation, The ratio V / S between the buffer volume V of the section and the opening area S of the intake pressure detection port is larger than 500 mm (V
/ S> 500 mm) is also a characteristic configuration of the present invention, and the control pressure detection port is an air flow connecting the air intake port provided in the instrument case and the intake port of the air supply means. Is it provided in a position inside the equipment case that is off the road,
Alternatively, it is also a characteristic configuration of the present invention that the control pressure measuring port is provided in the atmosphere outside the instrument case.

[0010]

In the present invention having the above-described structure, during the combustion operation of the combustion apparatus, the combustion air is supplied from the air supply means to the burner. The pressure introduced from the intake pressure detection port provided in the area,
The pressure introduced from the reference pressure detection port is compared, and the differential pressure is detected and output as a supply air flow rate detection signal. By analyzing the supply air flow rate detection signal, the supply air amount is accurately obtained, and the supply air amount according to the combustion amount is controlled based on the supply air flow rate detection signal.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows the configuration of the essential parts of a first embodiment of a combustion apparatus according to the present invention. Similarly to the conventional example, the combustion apparatus of the present embodiment is also shown by taking the water heater as an example. The same parts as those of the conventional example are designated by the same reference numerals, and the duplicate description will be omitted. In FIG. 1, the burner 3 and the hot water supply heat exchanger 4 are omitted in order to avoid complication of the drawing.

In this embodiment, an intake pressure detection port 8 is provided on the side peripheral surface of the intake port 7 of the combustion fan 2 which functions as an air supply means.
The pressure at the intake port 7 of the combustion fan 2 is introduced from the intake pressure detection port 8 through a pressure introduction passage 10 to a pressure introduction port of a pressure sensor 11 as a differential pressure flow rate detecting means.

A control pressure detecting port 12 is provided in the instrument case 1 for detecting the pressure in the instrument case as a reference control pressure. In order to prevent the influence of the flow velocity, the reference pressure detection port 12 is an air flow passage through which the air taken in from the air intake port 5 of the instrument case 1 flows to the intake port 7 of the combustion fan 2, that is, the air intake port 5 Is provided at a position deviating from the shortest straight path connecting the intake port 7 and the intake port 7. The pressure in the instrument case 1 introduced from the reference pressure detection port 12 is guided to the pressure sensor 11 via the pressure introduction passage 13.

The structure of the pressure sensor 11 is shown in FIG. In the figure, the inside of the housing 21 is divided by a diaphragm 22 into a first sensor chamber 23 and a second sensor chamber 24. The diaphragm 22 has an appropriate rigidity and is made of stainless SUS304 in order to reduce the weight, and is formed into a disk shape having a thickness of 20 μm and a diameter of 60 mm. Then, a plate piece of a magnetic material is fixedly arranged at a substantially central portion of the diaphragm 22 to form a magnetic body region 20. A sensor housing space 26 is formed on the wall surface side of the second sensor chamber 24 facing the magnetic body region 20, and a magnetic sensor 27 such as a Hall element is provided in the sensor housing space 26 with respect to the magnetic body region 20. They are arranged to face each other with a predetermined gap 28 in between. Further, a reference pressure introducing port 30 communicating with the second sensor chamber 24 is formed in the sensor housing space 26, the pressure introducing passage 13 is connected to the reference pressure introducing port 30, and the first sensor chamber 23. To the pressure detection inlet 29 communicating with the pressure introduction passage.
10 are connected.

The magnetic detection signal of the magnetic sensor 27 is applied to the control unit 31, which controls the magnetic sensor 27.
Of the combustion fan 2 and the outlet of the combustion fan 2 in order to detect the supply air amount supplied to the burner 3 from the combustion fan 2 by analyzing the magnetic detection signal of The amount of air supply is controlled by changing the opening / closing amount of a damper provided in the vehicle.

This embodiment is constructed as described above,
Next, the operation will be described. During the combustion operation of the water heater,
The combustion fan 2 is rotated, and the air introduced from the intake port 7 is supplied to the burner 3. At this time, the pressure at the intake pressure detection port 8 changes depending on the air flow rate at the intake port 7. When the air flow velocity at the intake port 7 is U ₁ , the pressure at the intake pressure detection port 8 is P ₁ , the air density is ρ, and the pressure (total pressure) at the reference pressure detection port 12 is P ₀ , the following equation holds. .

P ₀ = P ₁ + (1/2) ρU ₁ ² (1)

By rearranging the equation (1), the equation (2) is obtained.

U ₁ = {2 (P ₀ −P ₁ ) / ρ} ^1/2 (2)

[0020] Here, [rho is is constant, detecting a differential pressure of air velocity U ₁ of the air inlet 7 and the pressure P ₀ of the control pressure detection pressure port 12 and the pressure P ₁ in the intake test pressure port 8 Required by. Since the passage area of the intake port 7 is set at the design stage, the supply amount can be obtained by multiplying the known passage area of the intake port 7 by the air flow velocity U ₁ . This principle is in this embodiment the differential pressure of the P ₀ and P ₁ detected by the pressure sensor 11, obtains the supply amount by analyzing the signal the pressure detection signal by the control unit 31.

The pressure P ₁ of the intake pressure detecting port 8 is introduced into the first sensor chamber 23 via the pressure introducing passage 10, and the pressure P ₀ of the reference pressure detecting port 12 is introduced into the first sensor chamber 23 via the pressure introducing passage 13. Two sensor chambers 24 are introduced respectively. The diaphragm 22 is freely deformed according to the pressure difference between the pressures P ₀ and P ₁ , and the magnetic material region 20
And the distance 28 between the magnetic sensors 27 changes. The magnetic sensor 27 magnetically detects a change in the distance from the magnetic body region 20, and outputs a differential pressure detection signal corresponding to the distance as a supply air flow rate detection signal. That is, as the distance between the magnetic sensor 27 and the magnetic body region 20 becomes narrower, the magnetic sensor 27 detects stronger magnetism, and as a result, the output level of the detection signal from the magnetic sensor 27 becomes higher, and the distance between the magnetic body region 20 and the magnetic body region 20 increases. Becomes larger, the detection output of the magnetic sensor becomes smaller.

The magnitude of the detection signal of the magnetic sensor 27 is proportional to the amount of deformation of the diaphragm 22, that is, the magnitude of the pressure difference between P ₀ and P ₁ , and the magnitude of the output of the magnetic sensor 27 determines the intake air detection. The differential pressure between the pressure port 8 and the reference pressure detection port 12 can be accurately obtained.

In this embodiment, the pressure sensor 11 detects the differential pressure (P ₀ -P ₁ ) between the pressure P ₁ at the intake pressure detection port 8 and the pressure P ₀ at the control pressure detection port 12, and this differential pressure is detected. Since it is configured to detect the supply air amount of the combustion fan 2, the influence of the variation in the direction and speed of the air flow is smaller than in the case where the wind speed sensor 6 is provided in the air passage as in the conventional example. As a result, it is possible to more accurately obtain the supply air amount, and thus it is possible to improve the control accuracy of the supply air amount according to the combustion amount.

FIG. 3 shows a second embodiment of the present invention. This embodiment differs from the first embodiment in that
A donut-shaped intake pressure introducing unit 14 is attached to the side peripheral surface of the intake port 7 of the combustion fan 2, and a continuous slit opening 15 is formed as shown in FIG. 4 over the entire circumference of the donut-shaped inner peripheral surface. The slit opening 15 is used as the intake pressure detection port 8, and the other structure is the same as that of the first embodiment.

In this embodiment, since the slit openings 15 are formed over the entire circumference of the donut-shaped inner peripheral surface,
Compared with the case where the detected pressure P ₁ of the intake port 7 is detected at a local position, it is possible to suppress variations in the detected pressure and detect a more averaged detected pressure P _1, which is better than the first embodiment. The accuracy of pressure detection at the intake port 7 can be improved.

FIG. 5 shows a third embodiment of the present invention. In this embodiment, an intake pressure detection buffer 16 is provided in the middle of a pressure introduction passage 10 that guides the pressure P ₁ of the intake port 7 detected by the intake pressure introduction unit 14 from the intake pressure introduction unit 14 to the pressure sensor 11.
Other than that, the configuration is the same as that of the second embodiment. The intake pressure detection buffer section 16 is provided with a buffer volume V for buffering the pressure fluctuation of the pressure P ₁ detected at the slit opening 15 and its fluctuation. In this embodiment,
When the area of the slit opening 15 of the intake pressure introducing unit 14 is S, the ratio V / S between the buffer volume V and the opening area S of the slit is set to be larger than 500 mm (V / S> 500 mm).

6 to 12 show the slit opening 15 depending on the size of the slit width of the slit opening 15 and the size of V / S.
3 is a graph obtained by an experiment in which a change in behavior of the detected pressure is detected.
The horizontal axis of this graph represents the air flow rate, and the vertical axis represents the pressure P ₁ detected by the slit opening 15 and the reference pressure detection port 12
The differential pressure with respect to the pressure P ₀ detected at 1. is shown, and the air flow rate and the differential pressure are measured using a Pitot tube. When measuring the differential pressure for this air flow rate, the slit opening 15
To investigate the variation of the locational manometric of, A shifted the angular position by 90 °, B, the pressure P ₁ in the intake test pressure port 8 measured at three points and C, between P ₀ and P ₁ It is a graph showing the relationship between the differential pressure and the flow rate.

The graph shown in FIG. 6 shows the case where the slit width of the slit opening 15 is 1 mm, FIG. 7 shows the case where the slit width is 2.5 mm, and FIG. 8 shows the case where the slit width is 3.7 mm. These graphs of FIGS. 6 to 8 are V / S.
Both values are calculated under the condition of 20 mm. As can be seen from the graphs of FIGS. 6 to 8, it is understood that as the slit width of the slit opening 15 increases, the spatial variation in the measurement positions of A, B, and C decreases.

FIG. 9 is a graph of measurement data when the slit width of the slit opening 15 is 3.7 mm and the V / S value is 87 mm, as in the case of FIG. As is clear from the comparison between FIG. 8 and FIG. 9, it can be seen that by increasing the magnitude of V / S, the local measurement variation among the measurement positions A, B, C is reduced.

10 to 12 show that the value of V / S is at each measurement position A,
It is data obtained by further detailed experiments on the influence on the variation between B and C. In the experiments of FIGS. 10 to 12, the slit widths of the slit openings 15 are both set to 1 mm, and the value of V / S is varied. Fig. 10 is a graph when V / S is 74 mm, Fig. 11 is a graph when V / S value is 320 mm, and Fig. 12 is when V / S value is 554 mm. Each graph is shown. By comparing the graphs of FIGS. 10 to 12, it can be seen that the larger the value of V / S, the smaller the measurement variation among the measurement positions A, B, and C. When the relationship between the V / S value and the variation among the measurement positions A, B, and C was further tested, the V / S value was 50
It was proved that the measurement data with small variation between the pressure detection positions can be obtained by setting it to 0 mm or more.

FIG. 13 shows a fourth embodiment of the present invention. In this embodiment, the intake pressure detection buffer 16 is formed on the output side of the detection pressure of the intake pressure introducing unit 14 having a donut shape,
The intake pressure detection buffer section 16 is formed integrally with the intake pressure introducing unit 14, and the other structure is the same as that of the third embodiment. In this embodiment as well, as in the third embodiment, the ratio V / S of the slit opening area S of the slit opening 15 and the buffer volume V of the intake pressure sensing buffer 16 is set to 500 mm or more.

Also in the fourth embodiment, by providing the intake pressure detecting / buffering section 16, it is possible to suppress the variation variation of the detected pressure of the intake port 7 detected by the slit opening 15, so that the third embodiment can be realized. As in the example, it is possible to accurately detect the air supply amount.

The present invention is not limited to the above-mentioned embodiments, and various embodiments can be adopted. For example, in each of the above-described embodiments, the control pressure detection port 12 is provided in the instrument case 1, but the control pressure detection port 12 is used in the instrument case 1.
It may be provided in the air atmosphere outside.

Further, the pressure sensor 11 for detecting the differential pressure between the pressure P ₁ detected at the intake pressure detection port 8 and the pressure P ₀ detected at the reference pressure pressure detection port 12 is, for example, another one shown in FIGS. 14 and 15. It can be configured. The pressure sensor of FIG. 14 has a first sensor chamber 23
And the second sensor chamber 24 are each provided with a pressure detection inlet 29 and a reference pressure inlet 30 in the lateral direction. Further, FIG. 15 shows that the second sensor chamber 24 is filled with silicon or the like. It is filled with material. Note that this filling material is used in the first sensor chamber.
23 may be filled, or both sensor chambers 23 and 24 may be filled together.

Further, although the diaphragm 22 is formed of a stainless plate in the above embodiment, the diaphragm 22 may be any member made of a material having elasticity and resilience so that it is not deformed by its own weight and is made of metal other than stainless steel. It is also possible to use a synthetic resin having elasticity, a composite material thereof, or the like, or it is possible to use a flexible material such as rubber. In particular, when the diaphragm is formed by using a magnetic material such as nickel, the entire surface of the diaphragm 22 becomes a magnetic body region, and in this case, it was used in this example to form the magnetic body region. The magnetic piece can be omitted.

Further, in the above embodiment, the diaphragm is displaced by the pressure difference between the intake pressure detection port 8 and the reference pressure detection port 12.
The deflection amount of 22 was detected by the magnetic sensor 27, but the differential pressure deflection amount of this diaphragm may be detected by a capacitance type differential pressure sensor as a change in capacitance, and it may be detected by using another sensor. May be.

Further, in the above embodiment, as the combustion device,
Although the water heater has been described as an example, the present invention is also applied to other types of combustion devices such as a bath kettle that uses gas or oil as a fuel, and a heater.

[0038]

According to the present invention, the intake pressure detecting port is provided in the region around the intake port of the air supplying means, the reference pressure detecting port is provided at a position apart from the air supplying means, and the differential pressure flow rate detecting means is provided. Since the differential pressure between the intake pressure detection port and the reference pressure detection port is detected and the differential pressure is detected and output as a supply air flow rate detection signal, the outlet of the combustion fan as in the conventional example is used. It is possible to reduce the influence of variations in air flow direction and flow velocity that occur when the air supply amount is detected by installing a wind speed sensor, etc., and it is possible to detect the air supply amount more accurately than in the conventional example. .

In addition, a donut-shaped intake pressure introducing unit is attached to the intake port of the air supply means, and a slit opening of the intake pressure detection port is provided over the entire circumference of this donut-shaped inner peripheral surface. In addition, it is possible to further suppress the variation in the pressure detected at the intake port, and it is possible to more accurately detect the supply air amount.

Further, in a structure in which an intake pressure detecting buffer section having a buffer volume for suppressing pressure fluctuation is provided in the pressure introducing passage extending from the intake pressure detecting port to the differential pressure flow rate detecting means, the intake pressure detecting port Since the variation in the detected pressure fluctuation can be buffered and eliminated and the uniformed pressure detected at the intake port with no variation can be guided to the differential pressure flow rate detection means, the accuracy of the supply amount can be further improved, and in particular, By setting the ratio V / S of the buffer volume V of the intake pressure detecting / buffering portion and the opening area S of the intake pressure detecting port to be larger than 500 mm, the buffering / eliminating effect of the variation in the fluctuation of the detected pressure is remarkably enhanced. As a result, the accuracy of detection of the air supply amount is dramatically improved, and fine and suitable control of the air supply amount according to the combustion amount becomes possible.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a main part configuration showing a first embodiment of the present invention.

FIG. 2 is a structural explanatory view of a pressure sensor used as a differential pressure flow rate detection means.

FIG. 3 is an explanatory diagram of a main part configuration showing a second embodiment of the present invention.

4 is an explanatory view of an intake pressure introducing unit used in the device of FIG.

FIG. 5 is an explanatory diagram of a main part configuration showing a third embodiment of the present invention.

FIG. 6 is a graph showing a variation state of differential pressure data between respective pressure measurement positions when the opening slit width of the intake pressure introducing unit in the embodiment is set to 1 mm.

[Fig. 7] The opening slit width of the intake pressure introducing unit is 2.5 mm.
7 is a graph showing a variation state of the differential pressure data between the respective measurement positions at the time.

[Fig. 8] The slit opening width of the intake pressure introducing unit is 3.7 mm.
7 is a graph showing a variation state of the differential pressure data between the respective measurement positions at the time.

[Fig. 9] The slit opening width of the intake pressure introducing unit is 3.7 mm.
FIG. 9 is a graph showing a variation state of the differential pressure data between respective pressure measurement positions when the ratio of the buffer volume V of the intake pressure detecting and buffering section to the slit opening area S is increased from 20 mm in FIG. 8 to 87 mm.

FIG. 10 is a graph showing a variation state of differential pressure data between respective measurement positions when the slit opening width of the intake pressure introducing unit is 1 mm and V / S is 74 mm.

FIG. 11 is a graph showing a variation state of differential pressure data between respective measurement positions when the value of V / S is 320 mm.

FIG. 12 is a graph showing a variation state of differential pressure data between measurement positions with a V / S value set to 554 mm.

FIG. 13 is an explanatory diagram of a main part configuration showing a fourth embodiment of the present invention.

FIG. 14 is an explanatory diagram showing another configuration example of the pressure sensor used as the differential pressure flow rate detection means.

FIG. 15 is an explanatory diagram of still another configuration example of the pressure sensor.

FIG. 16 is an explanatory diagram of a general water heater as a combustion device.

[Explanation of symbols]

 1 Instrument case 2 Combustion fan 5 Air intake 7 Intake port 8 Intake pressure detecting port 11 Pressure sensor 12 Control pressure detecting port 14 Intake pressure introducing unit 15 Slit opening 16 Intake pressure detecting buffer section

Claims (6)

[Claims] 1. A burner provided in an instrument case, an air supply unit for supplying combustion air to the burner, and an air supply amount detection unit for detecting an air supply amount supplied from the air supply unit to the burner. In the combustion device for controlling the amount of combustion air according to the combustion amount based on the air supply amount detection information of the air supply amount detection means, the air supply amount detection means is a side periphery of an intake port of the air supply means. The intake pressure detection port provided in the area, the reference pressure detection port provided at a position distant from the air supply means, and the pressures of the intake pressure detection port and the reference pressure detection port are respectively introduced to supply the differential pressure. A combustion apparatus, comprising: a differential pressure flow rate detection means for detecting and outputting as a flow rate detection signal. 2. A donut-shaped intake pressure introducing unit is mounted around the intake port side of the air supply means, and a continuous slit opening is provided over the entire circumference of this donut-shaped inner peripheral surface. The combustion device according to claim 1, wherein the combustion device is a pressure port. 3. The combustion according to claim 1, wherein an intake pressure detection buffer section having a buffer volume for pressure fluctuation is provided in the pressure introduction passage extending from the intake pressure detection port to the differential pressure flow rate detection means. apparatus. 4. The ratio V / S between the buffer volume V of the intake pressure detecting buffer and the opening area S of the intake pressure detecting port is larger than 500 mm (V / S).
> 500 mm). 5. The control pressure measuring port is provided at a position inside the instrument case, which is out of an air flow passage connecting the air intake port provided in the instrument case and the intake port of the air supply means. The combustion device according to any one of 1. 6. The combustion apparatus according to claim 1, wherein the reference pressure detection port is provided in an air atmosphere outside the instrument case.