JP4034229B2 - Return nozzle type gun burner - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a return nozzle type gun burner used as a burner for a water heater or the like.
[0002]
[Prior art]
Conventionally, in this type of fuel, as disclosed in, for example, Patent Document 1, fuel oil pressurized by an electromagnetic pump is supplied from a fuel oil supply passage to a spray nozzle, and sprayed and burned here. At this time, by controlling the return amount returned through the return flow path by driving the oil proportional valve, the stepless combustion amount control according to the heat requirement amount is performed.
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 3-20516
[Problems to be solved by the invention]
By the way, the viscosity of the fuel oil flowing in the fuel oil supply path varies depending on the temperature. For example, if the oil temperature becomes high, the viscosity of the fuel oil decreases, and if the oil temperature becomes low, the viscosity of the fuel oil increases. As a result, the amount of spray from the fuel spray nozzle fluctuates due to the variation in the viscosity of the fuel oil, and when the burner is cold, more fuel oil is sprayed than the heat demand amount, and combustion is performed with a combustion amount larger than the heat demand amount. There was a problem of doing it.
[0005]
[Means for Solving the Problems]
Accordingly, in order to solve this problem, the present invention provides a fuel oil supply path including an electromagnetic pump that supplies fuel oil to the spray nozzle, a fuel oil supply path upstream of the spray nozzle and the electromagnetic pump. A return flow path that communicates with each other, an oil proportional valve that controls a combustion amount by controlling a return amount of fuel flowing in the return flow path, and a control unit that controls the oil proportional valve to start combustion at a required heat amount In a return nozzle type gun burner provided with a cooling state determining unit for determining the degree of cooling of the burner before starting combustion, and an output of the oil proportional valve corresponding to the heat demand according to the state determined by the cold state determining unit When the burner is determined to be in the cold state by the output correction unit that corrects the oil in the oil amount decreasing direction and the cold state determination unit, the oil proportional valve is controlled to the output corrected by the output correction unit and burned Start And a cold start control unit gently raise to the output corresponding to the heat demand is provided, wherein the output correction unit, the heat demand If there is less than a predetermined amount, and so not output correction of oil proportional valve It was supposed to be.
[0006]
As a result, normally, the control means controls the oil proportional valve output corresponding to the heat demand to start combustion, and when the cold state discriminating unit determines that the burner is in the cold state, output correction is performed. The oil proportional valve output is corrected in the oil quantity decreasing direction by the control unit, and the cold start control unit controls the oil proportional valve to start the combustion with this corrected output, and the output of the oil proportional valve changes to the output corresponding to the heat demand. By gradually rising and burning, even if the burner starts to burn in a cold state, it absorbs the deviation of the spray amount due to the viscosity change caused by the temperature change of the fuel oil until the burner warms up, and heat demand Combustion can be performed with a combustion amount substantially equal to the amount. Further, when the required heat amount is small, the amount of misalignment of the spray amount accompanying the change in viscosity due to the temperature change of the fuel oil is small, and unnecessary output correction of the oil proportional valve can be prevented.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of the present invention will be described with reference to the drawings.
A fuel oil return type spray nozzle 1 includes a distributor (not shown) having a return hole inside, and returns a part of the supplied fuel oil and swirls and burns the remaining fuel oil.
[0016]
A fuel oil supply path 2 connects the spray nozzle 1 and a fuel oil supply source (not shown) such as a fuel tank, and includes an electromagnetic pump 3 that pumps the fuel oil at a constant pressure.
[0017]
Reference numeral 4 denotes a return flow path that connects the return hole of the spray nozzle 1 and the fuel oil supply path 2 upstream of the electromagnetic pump 3, and is composed of an electromagnetic coil, a valve element, a spring, and the like (all not shown). The oil proportional valve 5 is provided, and the amount of opening from the current value supplied to the electromagnetic coil of the oil proportional valve 5 is varied to control the return amount, thereby determining the spray amount from the spray nozzle 1. Is a combustion fan for supplying combustion air.
[0018]
7 is an oil temperature sensor comprising a thermistor provided on the downstream side of the oil proportional valve 5 in the return flow path 4 and detects the temperature of the fuel oil flowing through the return flow path 4.
[0019]
Reference numeral 8 denotes a hot water supply passage through which hot water at a set temperature can be discharged from the hot water tap 9 at the end, and is provided with a heat exchanger 10 that receives the combustion heat of the spray nozzle 1 and is heated.
[0020]
Reference numeral 11 denotes a remote controller provided in the vicinity of the hot-water tap 9 and controlling an operation unit for performing various controls of the water heater. The remote controller 11 includes a temperature setting means 12, an operation switch 13, and the like that can appropriately set a desired hot water temperature.
[0021]
Reference numeral 14 denotes a hot water temperature sensor composed of a thermistor provided in the middle of the hot water supply passage 7 downstream of the heat exchanger 10, which always detects the actual hot water temperature, and 15 detects the hot water temperature upstream of the heat exchanger 10. This is a feed water temperature sensor composed of a thermistor. Reference numeral 16 denotes a flow rate sensor for detecting the flow rate flowing through the hot water supply passage 7.
[0022]
Reference numeral 17 denotes a control means having a microcomputer. The oil temperature sensor 7, the temperature setting means 12, the tapping temperature sensor 14, the feed water temperature sensor 15, and the flow rate sensor 16 are connected to the input side, and the output side is also connected. Is connected to the electromagnetic pump 3, the oil proportional valve 5, and the combustion fan 6. Then, the control means 17 calculates the required heat amount from the deviation between the set temperature of the temperature setting means 12 and the feed water temperature detected by the feed water temperature sensor 15 and the flow rate detected by the flow sensor 16, and corresponds to the required heat quantity. The opening degree of the oil proportional valve 5 is determined and controlled.
[0023]
Reference numeral 18 denotes a cold state determination unit programmed and provided as a function of the control means 17 for determining the degree of cooling of the burner before the start of combustion. In this embodiment, when the temperature detected by the oil temperature sensor 7 in the return flow path 4 is 10 ° C. or less, the burner is determined to be in a cold state, and a value that reflects the cooling condition of the burner is detected. It is possible to easily determine how much the burner is cold.
[0024]
An output correction unit 19 programmed and provided as a function of the control unit 17 reduces the oil amount of the output of the oil proportional valve 5 corresponding to the heat demand according to the state determined by the cold state determination unit 18. It corrects in the direction. In this embodiment, the output of the oil proportional valve 5 corresponding to the heat demand is set to 100%, and the correction output is reduced by 6% to 94%. For this correction amount, an appropriate value may be obtained in advance from the relationship between the fuel temperature and the spray amount. The output correction unit 19 corrects the output of the oil proportional valve 5 only when the required heat amount is equal to or greater than a predetermined amount. When the required heat amount is small, that is, when the spray amount is small, the fuel oil is in a cold state. Since the influence of the increase in the spray amount due to the fuel is small, the correction is not performed when the required heat amount is less than the predetermined amount.
[0025]
Reference numeral 20 denotes a cold start control unit programmed and provided as a function of the control unit 17. When the cold state determination unit 18 determines that the burner is in a cold state, the oil proportional valve 5 is connected to the output correction unit. The combustion is controlled by controlling the output corrected at 19 and gradually increased to an output corresponding to the required heat amount. In this embodiment, as shown in FIG. 2, the output is gradually increased by 1% every 30 seconds from the output of 94% of the required heat quantity corrected by the output correction unit 19, and the temperature of the burner is increased. As the viscosity of the fuel oil decreases, the output of the oil proportional valve 5 is brought close to the heat requirement amount so that the fuel oil is sprayed in accordance with the heat requirement amount. The method for gradually increasing the output is not limited to the method of this embodiment.
[0026]
Next, the operation of this embodiment will be described based on the flowchart shown in FIG.
First, when the control means 17 detects that the hot water tap 9 is opened and a heat request is generated (step 1, hereinafter abbreviated as S1), the cold state determination unit 18 determines whether the burner is in a cold state (S2). ). When the burner is in a cold state and the required heat amount is greater than or equal to a predetermined amount (S3), the output correcting unit 19 corrects the output of the oil proportional valve 5 so as to decrease below the required heat amount (S4).
[0027]
Then, the cold start control unit 20 controls the oil proportional valve 5 to the correction output corrected by the output correction unit 19 and starts combustion (S5). Thereafter, the output of the oil proportional valve 5 is gradually increased to the heat demand output (S6), and after reaching the heat demand output (S7), the heat demand at that time until the control means 17 disappears. The output of the oil proportional valve 5 is controlled so as to reach a quantity, and combustion is stopped (S9) when the heat demand disappears (S8).
[0028]
When the burner is determined not to be in the cold state in S2, or if the burner is in the cold state in S3 but the required heat amount is less than the predetermined amount, the control means 17 determines the heat request. Combustion is started at the output of the oil proportional valve 5 corresponding to the amount (S10).
[0029]
In this way, if it is determined that the burner is in a cold state, the burner is warmed because combustion is performed by controlling the output of the oil proportional valve 5 with a corrected output that is less than the output corresponding to the heat demand. In the meantime, it can be burned with a combustion amount almost corresponding to the heat demand, and the performance of the equipment can be fully exhibited.
[0030]
Here, FIG. 4 is a graph of the spray amount from the spray nozzle 1 from the start of combustion according to the present invention and the conventional spray amount, and as can be seen from the graph, conventionally, the burner starts combustion in a cold state. Then, until the burner warms up, excess fuel oil is sprayed with respect to the heat demand, and the hot water supply temperature overshoots, but the present invention (new system) warms the burner. Since the amount of fuel oil close to the required heat amount is sprayed in the meantime, the hot water supply temperature does not overshoot and the performance of the device can be fully exhibited.
[0031]
In addition, this invention is not limited to said one Embodiment, It can change in the range which does not change the summary of invention, For example, this return nozzle type gun burner is used for a heater instead of a water heater. Is also good.
[0032]
The cold state determination unit 18 only needs to be able to determine whether the burner is in a cold state before the start of combustion. For example, an oil temperature sensor is provided in the fuel supply path 2 between the spray nozzle 1 and the electromagnetic pump 3, You may make it discriminate | determine the cold state of a burner by the output of this oil temperature sensor.
[0033]
Further, the cold state determination unit 18 may count the time from the combustion stop, and may determine that the burner is in the cold state when the time from the combustion stop becomes a predetermined time or more. It is also possible to change the predetermined time according to the outside air temperature or the like, and it is possible to easily determine the degree of cooling of the burner. At this time, the cold state determination unit 18 performs combustion for a time longer than the time when the burner becomes high temperature, starts counting for a predetermined time from the time when this combustion is stopped, and this time the burner becomes high temperature. When the combustion time is less than the time, since the count from the previous time is continued, it is possible to reliably determine the degree of cooling of the burner.
[0034]
Further, the output correction unit 19 sets a fixed correction amount, but the correction is not limited to this, and the correction is performed according to the temperature of the burner determined by the cold state determination unit 18, for example, according to the temperature detected by the oil temperature sensor 7. The amount may be changed.
[0035]
【The invention's effect】
As described above, according to the present invention, when the control means normally controls the oil proportional valve output to the oil proportional valve output corresponding to the heat demand, combustion starts, and the cold state determination unit determines that the burner is in the cold state. When it is determined, the oil proportional valve output is corrected by the output correction unit in the direction of decreasing the oil amount, the cold start control unit controls the oil proportional valve to this correction output and starts combustion, and the output of the oil proportional valve is heated. By gradually rising to the output corresponding to the required amount and burning, the amount of spray that accompanies the change in viscosity due to the temperature change of the fuel oil is maintained even after the burner starts to burn in the cold state until the burner warms up. By absorbing the deviation, the combustion can be performed with the combustion amount substantially corresponding to the heat demand.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a water heater according to an embodiment of the present invention.
FIG. 2 is a diagram for explaining the operation of the cold start control unit of the same embodiment;
FIG. 3 is a flowchart for explaining the operation of the same embodiment.
FIG. 4 is a diagram for comparing and explaining the spray amount of the same embodiment and a conventional one.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Spray nozzle 2 Fuel oil supply path 3 Electromagnetic pump 4 Return flow path 5 Oil proportional valve 7 Oil temperature sensor 17 Control means 18 Cold state discrimination | determination part 19 Output correction part 20 Cold start control part

Claims (1)

A fuel supply path having an electromagnetic pump for supplying fuel to the spray nozzle, a return flow path communicating with the spray nozzle and a fuel supply path upstream of the electromagnetic pump, and a return of the fuel flowing in the return flow path In a return nozzle type gun burner comprising an oil proportional valve for controlling the combustion amount by quantity control and a control means for controlling the oil proportional valve to start combustion at a heat demand amount, the degree of cooling of the burner before starting combustion A cold state discriminating unit for judging the output, an output correcting unit for correcting the output of the oil proportional valve corresponding to the heat demand amount in the oil amount decreasing direction according to the state discriminated by the cold state discriminating unit, and the cold state discriminating unit When it is determined that the burner is in a cold state, the oil proportional valve is controlled to the output corrected by the output correction unit, combustion is started, and the cold soot is gradually increased to the output corresponding to the heat demand. Provided the over preparative controller, the output correction unit, if the heat demand is less than the predetermined amount, the return nozzle type Ganbana characterized in that so as not to perform output correction of oil proportional valve.

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