JPH0875144A - Gas burner - Google Patents

Abstract

PURPOSE: To provide gas combustion equipment which controls the amount of input of a fuel gas definitely irrespective of a nozzle back pressure and thereby eliminates the need for nozzle replacement and which is available in an optimum combustion state. CONSTITUTION: A water supply pipeline 1 and a hot water outlet pipeline 2 are installed to a heat exchanger 2. A positive-displacement pump VP is installed to a gas supply pipeline 9 which feeds gas to a gas burner which heats the heat exchanger 3 where the positive-displacement pump and a gas fan to the gas burner 4 are controlled with a controller 10. The types of gas to be fed to the gas burner 4 enters the controller 10 by mounting a pilot gas connector 12 or executing a pilot gas discriminant processing where proper combustion control is carried out in conformity with the types of gas without nozzle replacement. This construction makes it possible to provide hot water in conformity with a predetermined temperature in a stabilized manner.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a forced combustion type gas combustion apparatus having a blower fan, and more particularly, an improvement of a fuel control valve provided in a fuel supply system to a gas burner for increasing or decreasing the supply amount of fuel gas. It is about.

[0002]

2. Description of the Related Art Conventionally, a gas combustion device of this type has been used for gas appliances such as a gas water heater. A schematic configuration of an example of this will be described with reference to FIG. The gas water heater shown in FIG. 12 has a heat exchanger 53 in which a water supply pipe 51 and a hot water discharge pipe 52 are piped, a gas burner 54 for heating water flowing through the heat exchanger 53, and a combustion in the gas burner 54. And a blower fan 55 for supplying air for use.

The water supply pipe 51 is provided with a water flow switch 56 for detecting the flow of water, the hot water supply pipe 52 is provided with a hot water tap 57 for turning the hot water on and off, and a hot water discharge thermistor 58 for detecting the hot water temperature, and a gas burner. The fuel supply system (supply gas pipe 59) to 54 is provided with an original solenoid valve SV that shuts off the supply of fuel gas and a proportional control valve PV that adjusts the flow rate of gas, and these are connected to a burner controller 60. . A nozzle 66 that guides the supplied gas into the gas burner 54 is attached to the tip of the gas supply pipe 59. Further, the burner controller 6 is operated by the remote controller 61.
It is possible to instruct 0 to set the hot water temperature. Further, the gas species connector 62 provided in the burner controller 60 is directly related to the present application.

FIG. 13 is a control block diagram of this gas water heater. The above-mentioned water flow switch 56, hot water thermistor (hot water temperature detection unit) 58, remote controller (hot water temperature setting unit)
The signal of 61 is sent to a burner controller (combustion control unit) 60, and a command signal from this burner controller 60 causes the drive circuit 63 of the original solenoid valve SV, the drive circuit 64 of the proportional control valve PV, or the motor M of the blower fan 55. Drive circuit 65 is controlled. In addition, this burner controller 6
0 gas type connector (gas type setting unit) 62
Indicates to the burner controller 60 the type of fuel gas supplied to the gas burner 54 through the gas supply pipe 59. This is because the required gas input amount and gas / air ratio differ depending on the type of fuel gas.

Next, the outline of combustion control in the gas water heater having the above-mentioned schematic structure and control block will be described with reference to the flow chart of FIG. When the water flow switch 56 issues an ON signal, combustion control is started, and first in step (hereinafter referred to as "S") 51, a slow ignition process of the gas burner 54 is performed. Next, in step S52, the hot water discharge thermistor 58 detects the hot water discharge temperature. Then, in S53, the required input amount of fuel gas is calculated. This calculation is performed based on the hot water temperature detected in S52 by PID calculation so that the temperature becomes the set temperature of the remote controller 61. The output of the blower fan 55 for giving the optimum gas / air ratio to the input amount is also calculated. At this time, the type of fuel gas indicated by the gas type connector 62 is also taken into consideration. In S54, the proportional control valve PV is controlled via the drive circuit 64 based on the calculated value in S53. S55
In the same manner, similarly, the motor M of the blower fan 55 is controlled via the drive circuit 65 based on the calculated value in S53.

Then, in S56, the water flow switch 56
It is determined whether or not is turned off. Water flow switch 56
Is not turned off, that is, when it is determined that the water continues to flow (S56: No), the process returns to S52 and the operation for detecting the outlet heated water temperature is further continued. Water flow switch 56 with S56
Is determined to be off (S56: Yes),
Proceeding to S57, the combustion of the gas burner 54 is stopped. Thus, the combustion control ends. This gas water heater is characterized by being compatible with various fuel gases by replacing the gas type connector 62.

[0007]

However, the conventional gas combustion equipment described above has the following problems. That is, in the gas water heater of FIG. 12, the type of fuel gas is dealt with by replacing the gas type connector 62, and the burner controller 60 considers the calorific value of the gas type and the ideal air-fuel ratio and sets the set hot water temperature. The gas input amount and the blown air amount for obtaining the above are determined, and the proportional control valve PV and the motor M are controlled.

However, it may be difficult to obtain a stable combustion state in a wide temperature range from hot water to hot water depending on the kind of gas only by these controls. For example, when the back pressure of the nozzle 66 is low, it is difficult to obtain a desired gas input amount only by adjusting the opening degree of the proportional control valve PV, and combustion of the gas burner 54 becomes extremely unstable. Specifically, there are problems such as easy extinction of flame, generation of combustion noise, and generation of carbon monoxide gas due to incomplete combustion. Therefore, in practice, the nozzle 66 in addition to the gas type connector 62 needs to be replaced according to the type of fuel gas used.

The present invention has been made to solve the above problems, and an object thereof is to provide a positive displacement pump capable of reliably controlling the input amount of fuel gas regardless of the nozzle back pressure. It is an object of the present invention to provide a gas combustion device which does not require nozzle replacement as an adjustment by using and is responsive and can be used in an optimum combustion state by PID control or feedforward / feedback control.

[0010]

In order to achieve this object, a gas combustion apparatus (1) of the present invention comprises a gas burner for burning a fuel gas, a gas supply path for supplying the fuel gas to the gas burner, and an air for the gas burner. In a gas combustion device having a blower for supplying, a positive displacement fuel pump provided in the gas supply path for adjusting the supply amount of the fuel gas to the gas burner, and the fuel gas to the gas burner according to the type of the fuel gas Control unit that determines the supply amount of the air and the air blowing amount, a pump drive circuit that drives the positive displacement fuel pump based on the determined value of the control unit, and the air blower based on the determined value of the control unit. And a fan drive circuit for driving the.

Further, the gas combustion device (2) of the present invention comprises a heat exchanger for transmitting the heat generated by the gas burner to the internal water,
A water supply pipe for supplying water to the heat exchanger, a hot water discharge pipe for sending hot water from the heat exchanger, a hot water discharge temperature detecting means provided in the hot water discharge pipe to detect a hot water temperature, and a set temperature in the hot water discharge pipe is set. A temperature setting means, and the control means controls the amount of fuel gas supplied to the gas burner and the amount of air blown so that the hot water temperature detected by the hot water temperature detection means becomes the temperature set by the temperature setting means. The configuration (1) is characterized in that it is determined.

Further, the gas combustion device (3) of the present invention has a gas type instructing means for instructing the type of the fuel gas, and the control means responds to the gas type instructed by the gas type instructing means. The configuration of (2) is characterized in that the amount of fuel gas supplied to the gas burner and the amount of air blown are determined. Further, the gas combustion device (4) of the present invention comprises a flow rate detecting means provided in the water supply pipe for detecting a flow rate of water, and a water supply temperature detecting means provided in the water supply pipe for detecting a water temperature,
The type of the fuel gas supplied to the gas burner is determined from the flow rate detected by the flow rate detection means, the feed water temperature detected by the feed water temperature detection means, the hot water temperature detected by the hot water temperature detection means, and the supply amount of the fuel gas. A gas type discriminating means for discriminating, wherein the control means determines a supply amount of the fuel gas to the gas burner and an air blowing amount according to the gas type discriminated by the gas type discriminating means. The feature (2) is adopted.

[0013]

According to the gas combustion device (1) of the present invention having such a configuration, the control means controls the amount of fuel gas supplied to the gas burner according to the type of fuel gas supplied from the gas supply path to the gas burner. Determine the amount of air blown. Then, based on the determined value, the pump drive circuit drives the positive displacement fuel pump to accurately adjust the supply amount of the fuel gas, and the fan drive circuit drives the blower device to adjust the blown air amount. Thus, proper combustion in the gas burner is achieved.

Further, according to the gas combustion apparatus (2) of the present invention, the control means determines, based on the detected hot water temperature of the hot water temperature detecting means, the kind of the fuel gas supplied from the gas supply path to the gas burner. The amount of fuel gas supplied to the gas burner and the amount of air blown to the gas burner are determined so that the hot water outlet temperature becomes the temperature set by the temperature setting means. Then, based on the determined value, the pump drive circuit drives the positive displacement fuel pump to accurately adjust the supply amount of the fuel gas, and the fan drive circuit drives the blower device to adjust the blown air amount. Thus, the tap water at the set temperature can be obtained.

Further, in the gas combustion device (3) of the present invention,
The gas type instructing unit instructs the control unit as to the type of the fuel gas supplied to the gas burner, and the combustion is controlled like the gas combustion device (2) according to the instructed gas type. Also,
In the gas combustion device (4) of the present invention, first, the positive displacement fuel pump and the blower are driven under predetermined conditions, and at that time, the flow rate of the water supply pipe detected by the flow rate detection means and the water supply temperature detection means are detected. Based on the supplied water temperature, the hot water temperature detected by the hot water temperature detection means, and the supply amount of the fuel gas, the gas type determination means determines the type of fuel gas. Then, the control means controls combustion according to the determined gas type.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Some embodiments in which the present invention is embodied as a gas water heater will be described in detail below with reference to the drawings.
FIG. 1 shows the configuration of a gas water heater according to the first embodiment of the present invention. This gas water heater has a heat exchanger 3 in which a water supply pipe 1 and a hot water discharge pipe 2 are piped, a gas burner 4 for heating water flowing through the heat exchanger 3, and an air for combustion in the gas burner 4. Blower fan 5 for supplying and gas burner 4
And a supply gas pipe 9 for supplying the fuel gas to the.

Further, the water supply pipe 1 is provided with a water flow switch 6 for detecting the flow of water, the hot water discharge pipe 2 is provided with a hot water tap 7 for turning on / off the hot water, and a hot water discharge thermistor 8 for detecting the hot water temperature, and a gas burner. 4, a fuel supply system (supply gas pipe 9) is provided with an original solenoid valve SV for interrupting the supply of fuel gas and a positive displacement pump VP for adjusting the flow rate of gas, which are connected to a burner controller 10. . And
At the tip of the gas supply pipe 9, the supplied gas is supplied with the gas burner 4
A nozzle 16 for guiding the inside is attached. Further, the remote controller 11 can instruct the burner controller 10 to set the hot water outlet temperature. The burner controller 10 is equipped with a gas type connector 12 that indicates the type of fuel gas.

The positive displacement pump VP will be described. In this gas water heater, a positive displacement pump VP is used as a flow rate adjusting means for supplying the fuel gas to the gas burner 4. The positive displacement pump VP has an advantage that the gas supply can be reliably adjusted to a desired flow rate by controlling the rotation speed regardless of the back pressure. There are various types of positive displacement pumps such as an oval gear pump, a roots pump, and a rotary vane pump, and any of them can be used.

First, the outline of the oval gear pump will be described with reference to FIG. The oval gear pump includes an outer casing 41 and two oval gears 44 and 45 rotatably provided inside the casing 41. The rotary shafts 42 and 43 of the oval gears 44 and 45 are fixedly provided in the casing 41 in parallel with each other. The oval gears 44, 45 are gears having an elliptical cross section and having teeth cut on the peripheral surface, and are in contact with the inner surface of the casing 41 at the vertices. The oval gears 44 and 45 are always in mesh with each other at one central position and rotate in opposite directions as indicated by the arrow. When either of the oval gears 44 and 45 is vertical in the figure, the vertices at both ends contact the inner surface of the casing 41. Therefore, at this time, on the right side of FIG.
A sealed space 46 is formed between the casing 41 and the left side of (c).

When the oval gears 44 and 45 are rotated,
The fluid (here, fuel gas) applied to the IN side is drawn between the casing 41 and the oval gear 44 or 45 (on the left side in FIG. 4B), and is enclosed in the closed space 46 (FIG. 4 ( Left side of c)). If you continue to rotate,
As seen on the right side of (b), it is delivered from the closed space 46 to the OUT side. A total of four enclosed spaces 46 carry fluid during one revolution of the oval gear 44 or 45. Therefore, the flow rate p (m ³ / min) of the fluid passing through the oval gear pump
Is expressed as p = 4vs (m ³ / min) (1) when the volume of the closed space 46 is v (m ³ ) and the number of revolutions is s (revolutions / min), and is almost the same for back pressure. Not affected.

Next, an outline of the roots pump is shown in FIG.
The roots pump of FIG. 5 is obtained by replacing the oval gears 44, 45 of the oval gear pump of FIG. 4 with gourd-shaped rotors 47, 48, and operates similarly to the oval gear pump. The equation (1) for obtaining the flow rate p is similarly established. Next, an outline of the rotary vane pump is shown in FIG. The rotary vane pump of FIG. 6 has an outer housing 49, an inner rotor 50, and two vanes 51, 51 slidably provided on the rotor 50. A closed space 52 is formed by the inner surface of the housing 49, the outer surface of the rotor 50, and the two vanes 51, 51. When the rotor 50 is rotated, the vanes 51, 51 also rotate. Therefore, the closed space 52 also moves and the fluid is transported from the IN side to the OUT side. Since two vanes 51 are provided in the structure shown in FIG. 6, four closed spaces 5 are formed during one rotation of the rotor 50.
2 acts, and therefore the equation (1) holds.

FIG. 2 is a block diagram showing the control system of this gas water heater. The above-mentioned water flow switch 6, hot water thermistor (hot water temperature detection unit) 8, remote controller (hot water temperature setting unit)
The signal of 11 is sent to the burner controller (combustion control unit) 10, and the command signal from this burner controller 10 causes the drive circuit 13 of the original solenoid valve SV, the drive circuit 14 of the motor M1 of the positive displacement pump VP, or the blower fan 5 to operate. The drive circuit 15 of the motor M2 is controlled. The burner controller 10 has a remote controller 11 depending on the type of fuel gas.
There is a built-in program that calculates the gas input and the air flow to obtain the temperature set in.

The gas type connector (gas type setting unit) 12 provided in the burner controller 10 indicates to the burner controller 10 the type of fuel gas supplied to the gas burner 4 through the gas supply pipe 9. . This is because the required gas input amount and gas / air ratio differ depending on the type of fuel gas. Normally, when installing the gas water heater, the gas type connector 12 is set according to the type of gas supplied to the location.

Next, the outline of the combustion control in the gas water heater having the above-mentioned configuration and control block will be described with reference to the flowchart of FIG. When the hot water tap 7 is opened, the water flow switch 6 gives an ON signal and combustion control is started. First, in S1, a slow ignition process of the gas burner 4 is performed. Next, in S2, the hot water discharge thermistor 8 detects the hot water discharge temperature. Then, in S3, the required input amount of fuel gas is calculated. This calculation is performed by PID calculation based on the hot water temperature detected in S2 so that the temperature becomes the set temperature of the remote controller 11. That is, it is feedback control. The output of the blower fan 5 for giving the optimum gas / air ratio to the input amount is also calculated. At this time, the type of fuel gas indicated by the gas type connector 12 is also taken into consideration. This calculation is performed by the controller 10.

In S4, the motor M1 of the positive displacement pump VP is controlled via the drive circuit 14 based on the calculated value in S3. This is for inputting an appropriate flow rate of fuel gas. In S5, similarly, the motor M2 of the blower fan 5 is controlled via the drive circuit 15 based on the calculated value in S3. This is for supplying an appropriate flow rate of air. Then, in S6, it is determined whether or not the water flow switch 6 is turned off. If it is determined that the water flow switch 6 is not turned off, that is, if the water continues to flow (S6: No), the hot water tap 7 is not closed, so the process returns to S2 and the operation following the hot water outlet temperature detection is further continued. . When it is determined in S6 that the water flow switch 6 is off (S6: Yes),
Since the hot water tap 7 is closed, the routine proceeds to S7, where the combustion of the gas burner 4 is stopped and overheating is prevented. Thus, the combustion control ends.

The gas water heater having the above structure and operation has the following features. First, as the fuel gas supply amount adjusting means, a positive displacement pump VP is used instead of a general proportional valve.
Are using. According to the positive displacement pump VP, the input amount of the fuel gas can be accurately controlled by the rotation speed of the motor M1 based on the command of the controller 10, regardless of the back pressure of the nozzle 16. Therefore, the change of the fuel gas type can be dealt with only by replacing the gas type connector 12 in the controller 10, and the nozzle 16 need not be replaced. Since the controller 10 performs feedback control based on the hot water temperature detected by the hot water thermistor 8, the remote controller 1
It is possible to obtain hot water with the temperature set in 1.

Next, the gas water heater according to the second embodiment will be described. FIG. 7 shows the configuration of the gas water heater according to the second embodiment of the present invention. This gas water heater heats the heat exchanger 3 in which the water supply pipe 1 and the hot water discharge pipe 2 are piped, and the water flowing through the heat exchanger 3 in substantially the same manner as that of the first embodiment shown in FIG. A gas burner 4 for supplying the gas, a blower fan 5 for supplying combustion air to the gas burner 4, and a gas supply pipe 9 for supplying a fuel gas to the gas burner 4.

In addition to the hot-water tap 7 for turning the hot water on and off, the hot-water tap 2 has a hot water thermistor 8 for detecting the hot water temperature.
Further, the fuel supply system (supply gas pipe 9) to the gas burner 4 is provided with an original solenoid valve SV that cuts off the supply of the fuel gas and a positive displacement pump VP that adjusts the flow rate of the gas. It is connected to the. The positive displacement pump VP is the same as that of the first embodiment shown in FIGS. 4 to 6. A nozzle 16 for guiding the supplied gas into the gas burner 4 is attached to the tip of the gas supply pipe 9. Further, the remote controller 11 can instruct the burner controller 10 to set the hot water outlet temperature. On the other hand, the water supply pipe 1 is provided with a water amount sensor 17 for detecting the flow rate of water in place of the water flow switch 6, and the water supply pipe 1 is also provided with an inlet water thermistor 18 for detecting the inlet temperature. It differs from that of the first embodiment. Also,
It is not necessary to attach the gas type connector 12.

FIG. 8 is a block diagram showing the control system of this gas water heater. The control system of this gas water heater mainly includes a burner controller 10 having a control unit 21, a gas type determination storage unit 20, and an input determination unit 19.
The control unit 21 performs various calculations and commands described later. The gas type determination storage unit 20 determines and stores the type of fuel gas, and is a RAM for storing the gas type.
Alternatively, it has an EEPROM. The input determination unit 19 determines the gas input amount in order to determine the gas type in the gas type determination storage unit 20.

The above-mentioned water amount sensor (incoming water amount detecting portion) 17,
Hot water thermistor (hot water temperature detection unit) 8, water entering thermistor (water temperature detecting unit) 18, remote control (hot water temperature setting unit)
The signal of 11 is sent to the control unit 21, and the drive circuit 13 of the original solenoid valve SV, the drive circuit 14 of the motor M1 of the positive displacement pump VP, or the motor M2 of the blower fan 5 is driven by a command signal from the control unit 21. The circuit 15 is controlled. The control unit 21 includes a remote controller 11 according to the type of fuel gas.
There is a built-in program that calculates the gas input and the air flow to obtain the temperature set in.

The signals from the water quantity sensor 17, the hot water thermistor 8 and the water entering thermistor 18 are input to the input judging section 19.
Also sent to. The input determination unit 19 determines the input amount of fuel gas in a gas type determination process described later. The determination result is sent to the gas type determination storage unit 20. The gas type determination storage unit 20 determines the type of fuel gas supplied to the gas burner 4 based on the pump drive signal from the control unit 21 and the input amount, and instructs the control unit 21. This is because the required gas input amount and gas / air ratio differ depending on the type of fuel gas.

Next, an outline of combustion control in the gas water heater having the above configuration and control block is shown in FIGS. 9 and 1.
This will be described with reference to the flowchart of 0. The basic flow of combustion control is shown in FIG. When the hot water tap 7 is opened and the water amount sensor 17 detects a water amount that is equal to or larger than a predetermined ignitable water amount, combustion control is started. First, in S11, it is determined whether or not to determine the gas type. This gas water heater does not have the gas type connector 12 unlike the one in the first embodiment, so that it is necessary to discriminate by the burner controller 10 in principle. Specifically, the determination is made based on whether or not it is the first hot water supply after the power outlet of the gas water heater is turned on.

If it is judged that the gas type is to be discriminated, that is, if it is the first hot water supply after the insertion of the outlet (S1
1: Yes), the gas type determination process is performed in S12. The details will be described later. In S13, the gas type determined in S12 is displayed. This is so that it can be confirmed that the determination by the burner controller 10 is correct. The display is performed using the display of the remote controller 11. S
When it is determined that the gas type is not determined in 11, that is, when it is not the first hot water supply after the plug is turned on (S1
1: No), the slow ignition process of the gas burner 4 is performed in S14. This is because there is no need to make a new determination because the gas type has already been determined at the time of the previous hot water supply and the results have been saved. After the processing of S13 or S14, the process proceeds to S15. In S15, the water flow rate sensor 17 detects the incoming water flow rate, the incoming water thermistor 18 detects the incoming water temperature, and the outgoing hot water thermistor 8 detects the outgoing hot water temperature.

Then, in S16, the required input amount of fuel gas is calculated. This calculation is performed based on the incoming water flow rate, the incoming water temperature, and the outgoing hot water temperature detected in S15 by using both feedforward control and feedback control so that the outgoing hot water temperature becomes the set temperature of the remote controller 11.
The output of the blower fan 5 for giving the optimum gas / air ratio to the input amount is also calculated. Then S1
The type of fuel gas determined in 2 is also considered. This calculation is performed by the control unit 20 of the controller 10.

In the calculation here, first, the required input is calculated from the incoming water temperature, the hot water outlet temperature, and the set temperature, and the rotational speed of the positive displacement pump VP and the rotational speed of the blower fan 5 corresponding to the required input are calculated. , Based on a function stored in advance. An example of this function is shown in the graph of FIG. In the graph of FIG. 11, the rotational speed PA of the positive displacement pump VP and the rotational speed FA of the blower fan 5 in the case of 13A city gas, the rotational speed PL of the positive displacement pump VP and the rotational speed FL of the blower fan 5 in the case of LP gas. , And are shown for each required input. The required inputs are shown here as a percentage of the maximum possible input. A table may be used instead of using the function. The two types of 13A city gas and LP gas are shown here because they account for about 90% of the total, and most of these two are sufficient. When considering gases other than these, prepare a function or table for those gases.

In S17, the motor M of the positive displacement pump VP is driven through the drive circuit 14 based on the calculated value in S16.
Control 1 This is for inputting an appropriate flow rate of fuel gas. In S18, similarly, the motor M2 of the blower fan 5 is controlled via the drive circuit 15 based on the calculated value in S16. This is for supplying an appropriate flow rate of air. Then, in S19, it is determined whether or not the detection value of the water amount sensor 17 is less than or equal to a predetermined combustion stop water amount. When it is determined that the amount of water is not less than the combustion stop water, that is, it is determined that the water continues to flow (S19: No), the hot water tap 7 is still open. Continue further. If it is determined in S19 that the combustion stop water amount is equal to or less than (S19: Ye
s), since the hot water tap 7 is closed, the routine proceeds to S20, where the combustion of the gas burner 4 is stopped and overheating is prevented. Thus, the combustion control ends.

Next, the gas type discriminating process performed in S12 will be described with reference to the flowchart of FIG. In this process, first, the rotational speeds N _P and N _F of the positive displacement pump VP and the blower fan 5 are set (S21).
What is set here is the number of revolutions at the time of test combustion for gas type discrimination. Normally, when the gas type is 13A city gas, the number of revolutions is set to generate an output of 16875 kcal / h (an output called No. 9 output). This is because the output of No. 9 is an intermediate output in the usage state of the gas combustion equipment and does not cause excessive heat generation even when the LP gas having a large heat generation amount is supplied. In S22, combustion is started under that condition. Then, in S23, the water amount sensor 1
7. The water inflow amount Q ₀ , the water inflow temperature t ₀ , and the hot water outflow temperature t ₁ are detected by the water inflow thermistor 18 and the hot water thermistor 8.

At S24, based on the detected value at S23,
Estimate the input I ₀ . Input is the amount of heat given to water in the heat exchanger 3 per unit time (kcal /
h) is divided by the heat efficiency of the heat exchanger. This estimation is performed by I ₀ = (t ₁ −t ₀ ) · Q ₀ /0.8 (2). Here, 0.8 of the denominator on the right side is the heat exchanger 3
This is a coefficient that takes into account the heat transfer efficiency at.

In S25, the gas type is determined based on the input I ₀ calculated in S24. Specifically, I ₀
If (kcal / h) is within the range of 16875 × 0.9 <I ₀ <16875 × 1.1 (3), it is as set in S21.
It can be determined that the gas type is 13A city gas. Further, when 28303 × 0.9 <I ₀ <28303 × 1.1 (4), the gas type can be determined to be LP gas. This is because the theoretical value of the input when the LP gas is supplied with respect to the set conditions in S21 is 28303 kcal / h. As described above, the two types of 13A city gas and LP gas account for about 90% of the total, so this is usually sufficient for determining the gas type, but when considering other gases, The same judgment is made based on the theoretical value of gas. When the determined gas type is stored in S26, the process proceeds to S13 in FIG.

[0040] I _0/1687 in this case (3)
5, or (4) deviation from 1 of I _0/28303, the values in the equation, it is possible to correct the rotational speed of the motor M2 of S18 in FIG. 9. Specifically, if these values are, for example, 1.02, the number of revolutions is 1.02 with respect to that obtained from the graph or table of FIG.
Try to double. This is because the calorific value of the supply gas is not necessarily constant depending on the area even if the same LP gas is used, and the gas appliance side such as the gas burner 4 is ± 10.
This is because the tolerance of% is allowed. This is used to correct the fan rotation speed based on actual input estimation to further improve the control of combustion air fuel consumption. In addition,
The coefficient for this correction may be a stepwise value of about 5 to 7 steps from 0.9 to 1.1.

The gas water heater according to the second embodiment has the following features. First, as in the case of the first embodiment, by adopting the positive displacement pump VP as the fuel gas supply amount adjusting means, it is possible to cope with the change of the type of fuel gas without the need to replace the nozzle 16. Furthermore, since it was decided to perform test combustion for gas type discrimination and to discriminate the gas type from the results,
There is no need to replace the gas seed connector 12. By performing input estimation when determining the gas type, it becomes possible to control the fan rotation speed by correcting the actual gas heat generation amount and the error within the tolerance on the gas appliance side that differ slightly from region to region, and the air-fuel ratio control The accuracy can be further improved.

As described above in detail, in the gas water heater according to the first embodiment, the positive displacement pump VP is used as the fuel gas supply amount adjusting means instead of the general proportional valve. By controlling the number of nozzles 16
It is possible to control the input amount of fuel gas regardless of the back pressure.
Therefore, it is possible to deal with the change of the type of the fuel gas only by replacing the gas type connector 12 without replacing the nozzle 16. Further, since the controller 10 performs feedback control based on the hot water temperature detected by the hot water thermistor 8, it is possible to obtain hot water of the temperature set by the remote controller 11.

Further, in the gas water heater according to the second embodiment, since the gas type discrimination process is performed, it is not necessary to replace the gas type connector 12. Further, since the input estimation is performed for the gas type discrimination processing, it is possible to perform more precise control by correcting the actual calorific value of the supply gas and the tolerance of the gas appliance. The above embodiments do not limit the present invention at all, and needless to say, various modifications and improvements can be made without departing from the scope of the present invention.

[0044]

As is apparent from the above description, the gas combustion apparatus of the present invention is adjusted by using the positive displacement pump which can surely control the input amount of the fuel gas regardless of the nozzle back pressure. Therefore, the nozzle can be used in a good combustion state without changing the nozzle, depending on the type of fuel gas. Further, since the gas combustion device of the present invention determines the gas type by input estimation, it automatically corresponds to the type of fuel gas, and the actual gas calorific value and the tolerance of the gas appliance are corrected for combustion. It is possible to control the hot water temperature with higher accuracy.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a gas water heater according to a first embodiment.

FIG. 2 is a schematic block diagram showing the configuration of the gas water heater shown in FIG.

FIG. 3 is a flowchart of hot water supply control in this gas water heater.

FIG. 4 is a diagram illustrating a schematic configuration of an oval gear pump.

FIG. 5 is a diagram illustrating a schematic configuration of a roots pump.

FIG. 6 is a diagram illustrating a schematic configuration of a rotary vane pump.

FIG. 7 is a schematic configuration diagram of a gas water heater according to a second embodiment.

FIG. 8 is a schematic block diagram showing the configuration of the gas water heater shown in FIG.

FIG. 9 is a flowchart of hot water supply control in this gas water heater.

FIG. 10 is a flowchart of gas type determination processing.

FIG. 11 is a graph showing the relationship between the rotational speed of the positive displacement pump and the blower fan and the required input.

FIG. 12 is a schematic configuration diagram of a conventional gas water heater.

FIG. 13 is a schematic block diagram showing the configuration of the gas water heater shown in FIG.

FIG. 14 is a flowchart of hot water supply control in this gas water heater.

[Explanation of symbols]

 1 Water supply pipe 2 Hot water pipe 3 Heat exchanger 4 Gas burner 5 Blower fan 6 Water flow switch 8 Hot water discharge thermistor 9 Gas supply pipe 10 Controller 11 Remote control 12 Gas type connector 14 Pump drive circuit 15 Fan drive circuit 17 Water sensor 18 Water input thermistor VP Volumetric type pump

Claims (4)

[Claims] 1. A gas combustion apparatus having a gas burner for burning a fuel gas, a gas supply path for supplying the fuel gas to the gas burner, and an air blower for supplying air to the gas burner, wherein the gas burner is provided in the gas supply path. A positive displacement fuel pump that adjusts the supply amount of the fuel gas, a control unit that determines the supply amount of the fuel gas to the gas burner and the air blowing amount according to the type of the fuel gas, and the determination of the control unit A gas combustion device comprising: a pump drive circuit that drives the positive displacement fuel pump based on a value; and a fan drive circuit that drives the blower based on a determined value of the control means. 2. A heat exchanger for transmitting heat generated in the gas burner to internal water, a water supply pipe for supplying water to the heat exchanger, a hot water discharge pipe for sending hot water from the heat exchanger, and a hot water supply pipe provided for the hot water discharge pipe. A hot water temperature detecting means for detecting a hot water temperature and a temperature setting means for setting a set temperature in the hot water pipe, wherein the control means sets the hot water temperature detected by the hot water temperature detecting means by the temperature setting means. The gas combustion device according to claim 1, wherein the supply amount of the fuel gas and the air blowing amount to the gas burner are determined so as to reach the temperature. 3. A gas type instructing unit for instructing the type of the fuel gas, wherein the control unit supplies the amount of the fuel gas to the gas burner according to the gas type instructed by the gas type instructing unit. The gas combustion device according to claim 2, wherein the amount of air blown is determined. 4. A flow rate detecting means provided in the water supply pipe for detecting a flow rate of water, a water supply temperature detecting means provided in the water supply pipe for detecting a water temperature, a flow rate detected by the flow rate detecting means and the water supply temperature. A hot water temperature detected by a detection means, a hot water temperature detected by the hot water temperature detection means, and a supply amount of the fuel gas; and a gas type determination means for determining the type of the fuel gas supplied to the gas burner, The gas combustion apparatus according to claim 2, wherein the control unit determines the supply amount of the fuel gas to the gas burner and the air blowing amount according to the gas type determined by the gas type determination unit. .